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Sample records for lead target irradiated

  1. Influence of Different Moderator Materials on Characteristics of Neutron Fluxes Generated under Irradiation of Lead Target with Proton Beams

    CERN Document Server

    Sosnin, A N; Polanski, A; Petrochenkov, S A; Golovatyuk, V M; Krivopustov, M I; Bamblevski, V P; Westmeier, W; Odoj, R; Brandt, R; Robotham, H; Hashemi-Nezhad, S R; Zamani-Valassiadou, M

    2002-01-01

    Neutron fields generated in extended heavy (Z\\geq 82) targets under irradiation with proton beams at energies in the range of 1 GeV are investigated. Influence of different moderators on the spectra and multiplicities of neutrons escaping the surface of the assembly consisting of a lead target (\\varnothing 8 cm\\times 20 cm or \\varnothing 8cm\\times 50 cm) screened by variable thickness of polyethylene or graphite, respectively, was compared in the present work. It is shown that the effectiveness of graphite as a material used in such assemblies to moderate spallation neutrons down to thermal energies is significantly lower than that of paraffin.

  2. Post-irradiation analysis of an ISOLDE lead-bismuth target: Stable and long-lived noble gas nuclides

    Science.gov (United States)

    Leya, I.; Grimberg, A.; David, J.-C.; Schumann, D.; Neuhausen, J.; Zanini, L.; Noah, E.

    2016-07-01

    We measured the isotopic concentrations of long-lived and stable He, Ne, Ar, Kr, and Xe isotopes in a sample from a lead-bismuth eutectic target irradiated with 1.0 and 1.4 GeV protons. Our data indicate for most noble gases nearly complete release with retention fractions in the range of percent or less. Higher retention fractions result from the decay of long-lived radioactive progenitors from groups 1, 2, or 7 of the periodic table. From the data we can calculate a retention fraction for 3H of 2-3%. For alkaline metals we find retention fractions of about 10%, 30%, and 50% for Na, Rb, and Cs, respectively. For the alkaline earth metal Ba we found complete retention. Finally, the measured Kr and Xe concentrations indicate that there was some release of the halogens Br and I during and/or after the irradiation.

  3. Spatial distribution of neutrons in paraffin moderator surrounding a lead target irradiated with protons at intermediate energies

    CERN Document Server

    Adam, J; Bradnova, V

    2002-01-01

    The distribution of neutrons emitted during the irradiation with 0.65, 1.0 and 1.5 GeV protons from a lead target (O / = 8 cm, l = 20 cm) and moderated by a surrounding paraffin moderator of 6 cm thick was studied with a radiochemical sensor along the beam axis on top of the moderator. Small sup 1 sup 3 sup 9 La-sensors of approximately 1 g were used to measure essentially the thermal neutron fluence at different depths near the surface: i.e., on top of the moderator, in 10 mm deep holes and in 20 mm deep holes. The reaction sup 1 sup 3 sup 9 La(n, gamma) sup 1 sup 4 sup 0 La (tau sub 1 sub / sub 2 = 40.27 h) was studied using standard procedures of gamma spectroscopy and data analysis. The neutron induced activity of sup 1 sup 4 sup 0 La increases strongly with the depth of the hole inside the moderator, its activity distribution along the beam direction on top of the moderator has its maximum about 10 cm downstream the entrance of the protons into the lead and the induced activity increases about linearity ...

  4. Spallation Neutron Spectrum on a Massive Lead/Paraffin Target Irradiated with 1 GeV Protons

    CERN Document Server

    Adam, J; Barashenkov, V S; Brandt, R; Golovatiouk, V M; Kalinnikov, V G; Katovsky, K; Krivopustov, M I; Kumar, V; Kumawat, H; Odoj, R; Pronskikh, V S; Solnyshkin, A A; Stegailov, V I; Tsoupko-Sitnikov, V M; Westmeier, W

    2004-01-01

    The spectra of gamma-ray emitted by decaying residual nuclei, produced by spallation neutrons with (n, xn), (n,xnyp), (n,p), (n,gamma) reactions in activation threshold detectors - namely, ^{209}Bi, ^{197}Au, ^{59}Co, ^{115}In, ^{232}Th, were measured in the Laboratory of Nuclear Problems (LNP), JINR, Dubna, Russia. Spallation neutrons were generated by bombarding a 20 cm long cylindrical lead target, 8 cm in diameter, surrounded by a 6 cm thick layer of paraffin moderator, with a 1 GeV proton beam from the Nuclotron accelerator. Reaction rates and spallation neutron spectrum were measured and compared with CASCADE code calculations.

  5. Radiochemical determination of {sup 129}I and {sup 36}Cl in MEGAPIE, a proton irradiated lead-bismuth eutectic spallation target

    Energy Technology Data Exchange (ETDEWEB)

    Hammer-Rotzler, Bernadette; Tuerler, Andreas [Paul Scherrer Institut (PSI), Villigen (Switzerland); Bern Univ. (Switzerland); Neuhausen, Joerg; Boutellier, Viktor; Wohlmuther, Michael; Schumann, Dorothea [Paul Scherrer Institut (PSI), Villigen (Switzerland); Vockenhuber, Christof [ETH Zurich (Switzerland). Lab. of Ion Beam Physics

    2015-07-01

    The concentrations of the long-lived nuclear reaction products {sup 129}I and {sup 36}Cl have been measured in samples from the MEGAPIE liquid metal spallation target. Samples from the bulk target material (lead-bismuth eutectic, LBE), from the interface of the metal free surface with the cover gas, from LBE/steel interfaces and from noble metal absorber foils installed in the cover gas system were analysed using Accelerator Mass Spectrometry at the Laboratory of Ion beam Physics at ETH Zuerich. The major part of {sup 129}I and {sup 36}Cl was found accumulated on the interfaces, particularly at the interface of LBE and the steel walls of the target container, while bulk LBE samples contain only a minor fraction of these nuclides. Both nuclides were also detected on the absorber foils to a certain extent (<< 1% of the total amount). The latter number is negligible concerning the radio-hazard of the irradiated target material; however it indicates a certain affinity of the absorber foils for halogens, thus proving the principle of using noble metal foils for catching these volatile radionuclides. The total amounts of {sup 129}I and {sup 36}Cl in the target were estimated from the analytical data by averaging within the different groups of samples and summing up these averages over the total target. This estimation could account for about half of the amount of {sup 129}I and {sup 36}Cl predicted to be produced using nuclear physics modelling codes for both nuclides. The significance of the results and the associated uncertainties are discussed.

  6. Volatile elements production rates in a 1.4 Gev proton-irradiated molten lead-bismuth target

    CERN Document Server

    Zanini, L; Everaerts, P; Fallot, M; Franberg, H; Gröschel, F; Jost, C; Kirchner, T; Kojima, Y; Köster, U; Lebenhaft, J; Manfrina, E; Pitcher, E J; Ravn, H L; Tall, Y; Wagner, W; Wohlmuther, M

    2005-01-01

    Production rates of volatile elements following spallation reaction of 1.4 GeV protons on a liquid Pb/Bi target have been measured. The experiment was performed at the ISOLDE facility at CERN. These data are of interest for the developments of targets for accelerator driven systems such as MEGAPIE. Additional data have been taken on a liquid Pb target. Calculations were performed using the FLUKA and MCNPX Monte Carlo codes coupled with the evolution codes ORIHET3 and FISPACT using different options for the intra-nuclear cascades and evaporation models. Preliminary results from the data analysis show good comparison with calculations for Hg and for noble gases. For other elements such as I it is apparent that only a fraction of the produced isotopes is released. The agreement with the experimental data varies depending on the model combination used. The best results are obtained using MCNPX with the INCL4/ABLA models and with FLUKA. Discrepancies are found for some isotopes produced by fission using the MCNPX ...

  7. Target irradiation experiments. [Hydra accelerator

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Target irradiation experiments have been carried out on the Hydra accelerator, operating at powers between 0.15 and 0.3 TW. As listed in Table I, four types of spherical shell targets have been studied: 3 mm diameter, 200 ..mu..m and 50 ..mu..m wall thickness Au targets; 3 mm diameter, 300 ..mu..m wall thickness plastic targets; and 0.85 mm diameter, 10 ..mu..m wall thickness Ni targets. When compared to a practical range for 700 keV electrons, the ratio of shell thickness to electron range varied between 0.03 for the Ni targets to 1.5 for the thick walled Au targets. Multiple exposure optical holography was utilized to determine ablator velocity, and a one-dimensional hydrodynamical materials code CHARTD was utilized to model target response and infer beam deposition. Energy deposition varied from 1 TW/gm for thick Au targets up to 8 TW/gm for thin Ni targets, and pusher velocities ranged between 0.5 and 3.5 cm/..mu..sec. Neutron production from D/sub 2/ and DT filled Ni exploding pusher targets was measured using Ag and Li activation counters and gated scintillator photomultiplier time of flight detectors.

  8. Uranium briquettes for irradiation target

    Energy Technology Data Exchange (ETDEWEB)

    Saliba-Silva, Adonis Marcelo; Garcia, Rafael Henrique Lazzari; Martins, Ilson Carlos; Carvalho, Elita Fontenele Urano de; Durazzo, Michelangelo, E-mail: saliba@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Direct irradiation on targets inside nuclear research or multiple purpose reactors is a common route to produce {sup 99}Mo-{sup 99m}Tc radioisotopes. Nevertheless, since the imposed limits to use LEU uranium to prevent nuclear armament production, the amount of uranium loaded in target meats has physically increased and new processes have been proposed for production. Routes using metallic uranium thin film and UAl{sub x} dispersion have been used for this purpose. Both routes have their own issues, either by bringing difficulties to disassemble the aluminum case inside hot cells or by generating great amount of alkaline radioactive liquid rejects. A potential route might be the dispersion of powders of LEU metallic uranium and nickel, which are pressed as a blend inside a die and followed by pulse electroplating of nickel. The electroplating provides more strength to the briquettes and creates a barrier for gas evolution during neutronic disintegration of {sup 235}U. A target briquette platted with nickel encapsulated in an aluminum case to be irradiated may be an alternative possibility to replace other proposed targets. This work uses pulse Ni-electroplating over iron powder briquette to simulate the covering of uranium by nickel. The following parameters were applied 10 times for each sample: 900Hz, -0.84A/square centimeters with duty cycle of 0.1 in Watts Bath. It also presented the optical microscopy analysis of plated microstructure section. (author)

  9. Target engagement in lead generation.

    Science.gov (United States)

    Durham, Timothy B; Blanco, Maria-Jesus

    2015-03-01

    The pharmaceutical industry is currently facing multiple challenges, in particular the low number of new drug approvals in spite of the high level of R&D investment. In order to improve target selection and assess properly the clinical hypothesis, it is important to start building an integrated drug discovery approach during Lead Generation. This should include special emphasis on evaluating target engagement in the target tissue and linking preclinical to clinical readouts. In this review, we would like to illustrate several strategies and technologies for assessing target engagement and the value of its application to medicinal chemistry efforts.

  10. Investigation of Space and Energy Distributions of Neutrons Generated in Lead Target and Uranium Blanket of the Electronuclear System "Energy plus Transmutation" under Irradiation with Protons at 1.5 GeV

    CERN Document Server

    Zhuk, I V; Krivopustov, M I; Sosnin, A N; Chultem, D; Vestmaer, V; Tumendelger, T; Zaveryukha, O S; Pavlyuk, A B

    2002-01-01

    The work contains the results of space-energy distributions of neutrons in U/Pb assembly, consisting of extended lead target and the model of natural uranium blanket irradiated with relativistic protons at 1.5 GeV. The research is carried out in the framework of a series of experiments using the model of subcritical heterogeneous electronuclear system at the Laboratory of High Energies, JINR, Dubna ("Investigation of Physical Aspects of Electronuclear Method of Energy Production and Transmutation of Radioactive Waste Using Beams from JINR Synchrophasotron/Nuclotron" - project "Energy plus Transmutation"). The results of measurements and calculations of ^{235}U, ^{238}U and ^{232}Th fission rate distributions as well as threshold spectral indexes {\\bar\\sigma_f^{^{232}Th}}/{\\bar\\sigma_f^{^{235}U}} and {\\bar\\sigma_f^{^{238}U}}/{\\bar\\sigma_f^{^{235}U}} along the radius of the target and model uranium blanket are presented. The results of measurements and calculations of ^{234}U, ^{236}U and ^{237}Np fission rate ...

  11. Irradiation of target volumes with concave outlines

    Energy Technology Data Exchange (ETDEWEB)

    De Neve, W.; Fortan, L.; Derycke, S.; Van Duyse, B.; DE Wagter, C. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde

    1995-12-01

    A heuristic planning procedure allowing to obtain a 3-dimensional conformal dose distribution for target volumes with concavities has been investigated. The procedure divides the planning problem into a number of sub-problems each solvable by known methods. By patching together the solutions to the sub-problems, a solution with a predictable dosimetric outcome can be obtained. The procedure can be applied to most 3-dimensional systems. The procedure is described and its applications to the irradiation of neoplasms are discussed. (A.S.).

  12. Thermal Convection on an Irradiated Target

    Science.gov (United States)

    Mehmedagic, Igbal; Thangam, Siva

    2016-11-01

    The present work involves the computational modeling of metallic targets subject to steady and high intensity heat flux. The ablation and associated fluid dynamics when metallic surfaces are exposed to high intensity laser fluence at normal atmospheric conditions is modelled. The incident energy from the laser is partly absorbed and partly reflected by the surface during ablation and subsequent vaporization of the melt. Computational findings based on effective representation and prediction of the heat transfer, melting and vaporization of the targeting material as well as plume formation and expansion are presented and discussed in the context of various ablation mechanisms, variable thermo-physical and optical properties, plume expansion and surface geometry. The energy distribution during the process between the bulk and vapor phase strongly depends on optical and thermodynamic properties of the irradiated material, radiation wavelength, and laser intensity. The relevance of the findings to various manufacturing processes as well as for the development of protective shields is discussed. Funded in part by U. S. Army ARDEC, Picatinny Arsenal, NJ.

  13. Final Report on MEGAPIE Target Irradiation and Post-Irradiation Examination

    Energy Technology Data Exchange (ETDEWEB)

    Yong, Dai [Paul Scherrer-Institut (Switzerland)

    2015-06-30

    Megawatt pilot experiment (MEGAPIE) was successfully performed in 2006. One of the important goals of MEGAPIE is to understand the behaviour of structural materials of the target components exposed to high fluxes of high-energy protons and spallation neutrons in flowing LBE (liquid lead-bismuth eutectic) environment by conducting post-irradiation examination (PIE). The PIE includes four major parts: non-destructive test, radiochemical analysis of production and distribution of radionuclides produced by spallation reaction in LBE, analysis of LBE corrosion effects on structural materials, T91 and SS 316L steels, and mechanical testing of the T91 and SS 316L steels irradiated in the lower part of the target. The non-destructive test (NDT) including visual inspection and ultrasonic measurement was performed in the proton beam window area of the T91 calotte of the LBE container, the most intensively irradiated part of the MEGAPIE target. The visual inspection showed no visible failure and the ultrasonic measurement demonstrated no detectable change in thickness in the beam window area. Gamma mapping was also performed in the proton beam window area of the AlMg3 safety-container. The gamma mapping results were used to evaluate the accumulated proton fluence distribution profile, the input data for determining irradiation parameters. Radiochemical analysis of radionuclides produced by spallation reaction in LBE is to improve the understanding of the production and distribution of radionuclides in the target. The results demonstrate that the radionuclides of noble metals, 207Bi, 194Hg/Au are rather homogeneously distributed within the target, while radionuclides of electropositive elements are found to be deposited on the steel-LBE interface. The corrosion effect of LBE on the structural components under intensive irradiation was investigated by metallography. The results show that no evident corrosion damages. However, unexpected deep

  14. Measurements of gas and volatile element production rates from an irradiated molten lead and lead-bismuth spallation target with proton beams of 1 and 1.4 GeV; Mesures de taux de production d'elements gazeux et volatiles lors de reactions induites par des protons de 1 et 1,4 GeV sur des cibles epaisses de plomb et plomb-bismuth liquides

    Energy Technology Data Exchange (ETDEWEB)

    Tall, Y

    2008-03-15

    The integrated project EUROTRANS (European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System) of the 6. EURATOM Framework Programme aims to demonstrate the transmutation of radioactive waste in ADS (Accelerator Driven Sub-critical system). It will carry out a first advanced design of an experimental facility to demonstrate the technical feasibility of transmutation, and will produce a conceptual design of an industrial facility dedicated to transmutation. An ADS consists of three fundamental elements: the accelerator of protons, the sub-critical core and the spallation target. SUBATECH (physique Sub-Atomique et des Technologies associees) laboratory is involved to the study of the chosen liquid lead-bismuth as a spallation ADS target. The irradiation of liquid lead-bismuth target with energetic proton beam generates in addition to neutrons, volatile and radioactive residues. In order to determine experimentally the production rates of gas and volatile elements following a spallation reaction in a lead-bismuth target, the experiment IS419 was performed at the ISOLDE facility at CERN (Centre Europeen de la Recherche Nucleaire). This experiment constitutes the frame of the thesis whose main objective is to assess and study the production and release rates of many gas and volatile element from the irradiated lead-bismuth target with an energetic proton beam. The obtained data are compared to Monte Carlo simulation code (MCNPX) results in order to test the intranuclear cascade model of Bertini and of Cugnon, and the evaporation options of Dresner and Schmidt. (author)

  15. The BLAIRR Irradiation Facility Hybrid Spallation Target Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Simos N.; Hanson A.; Brown, D.; Elbakhshawn, M.

    2016-04-11

    BLAIRR STUDY STATUS OVERVIEW Beamline Complex Evaluation/Assessment and Adaptation to the Goals Facility Radiological Constraints ? Large scale analyses of conventional facility and integrated shield (concrete, soil)Target Optimization and Design: Beam-target interaction optimization Hadronic interaction and energy deposition limitations Single phase and Hybrid target concepts Irradiation Damage Thermo-mechanical considerations Spallation neutron fluence optimization for (a) fast neutron irradiation damage (b) moderator/reflector studies, (c) NTOF potential and optimization (d) mono-energetic neutron beam

  16. Specific Activity and Impurities in Irradiated Natural Nickel Target

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this paper, the specific activity of the 63Ni which is produced by irradiating natural nickel in a nuclear reactor is calculated. And in the 1 g irradiated natural nickel target, the species of the key impurity nuclides were analyzed,

  17. Erosion of Copper Target Irradiated by Ion Beam

    CERN Document Server

    Polosatkin, S V; Grishnyaev, E S; Konstantinov, S G; Shoshin, A A

    2012-01-01

    Erosion of copper target irradiated by deuterium ion beam with ultimate fluence is studied. The target originally destined for neutron generation represents bulk copper substrate covered by 3-\\mum titanium layer. The target was irradiated by deuterium ion beam generated in Bayard-Alpert type ion source with energy of ions 17.5 keV/nuclear. Maximal fluence in the center of the target achieves 2.5x10^23atoms/cm^2. Measurements of the profile of irradiated target and estimation of fluence shows that physical sputtering is a dominating process that determines the target erosion Most interesting feature is growth of \\mum-size tadpole-shaped structures, localized in the cracks of the surface. RFA analysis of these structures showed extremely large (up to 60%at.) carbon content.

  18. Thin lead sheets as tissue compensators for larger field irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, K.P.; Baxter, D.H.; Ray, P.

    1980-04-01

    This paper describes the use of a thin lead sheet as a tissue compensating filter when a large field that includes the supraclavicular and mediastinal regions is irradiated. The typical midplane depths between supraclavicular and mediastinal regions may vary between 6 to 12 cm. Flattening of the beam entry surface is necessary for dose uniformity; this is achieved with a thin lead sheet compensating filter on the shadow tray of a 4 MV Unit. The shadow tray also contains lead shielding blocks for lung, cervical spinal cord, and larynx. The advantages of using thin lead sheets include easy maneuverability of shaping and sizing for irregular fields, and the small dimensions that are needed. Dose uniformity is verified by measuring optical densities from the film that is taken with the actual tray containing this compensating filter. This compensating filter may be extended to many situations where there are marked dose variations between different locations within the same large radiation field. The electron contamination produced by the scattering medium being placed in the beam is less for lead than for aluminum and wax. This contamination is also insignificant when the scatterer is more than 20 cm. away from the patient's skin surface when Cobalt-60 and 4 MV units are used.

  19. Post-Irradiation Examination of Array Targets - Part I

    Energy Technology Data Exchange (ETDEWEB)

    Icenhour, A.S.

    2004-01-23

    During FY 2001, two arrays, each containing seven neptunium-loaded targets, were irradiated at the Advanced Test Reactor in Idaho to examine the influence of multi-target self-shielding on {sup 236}Pu content and to evaluate fission product release data. One array consisted of seven targets that contained 10 vol% NpO{sub 2} pellets, while the other array consisted of seven targets that contained 20 vol % NpO{sub 2} pellets. The arrays were located in the same irradiation facility but were axially separated to minimize the influence of one array on the other. Each target also contained a dosimeter package, which consisted of a small NpO{sub 2} wire that was inside a vanadium container. After completion of irradiation and shipment back to the Oak Ridge National Laboratory, nine of the targets (four from the 10 vol% array and five from the 20 vol% array) were punctured for pressure measurement and measurement of {sup 85}Kr. These nine targets and the associated dosimeters were then chemically processed to measure the residual neptunium, total plutonium production, {sup 238}Pu production, and {sup 236}Pu concentration at discharge. The amount and isotopic composition of fission products were also measured. This report provides the results of the processing and analysis of the nine targets.

  20. Target volume definition and target conformal irradiation technique for breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Kiricuta, I.C.; Gotz, U.; Schwab, F.; Fehn, M.; Neumann, H.H. [St. Vincenz-Hospital, Limburg (Germany). Inst. of Radiation Oncology

    2000-07-01

    The aim of this study was to present the target volume and irradiation technique in the most complex situation where the breast or chest wall and the locoregional lymphatics (mammarial internal lymph nodes, axillary and supraclavicular lymph nodes) have to be irradiated. The study comprised 125 breast cancer patients treated with curative intent after primary surgery in the last two years at our institute. In 62 cases the target volume included the breast or chest wall and the locoregional lymphatics, which were treated using our irradiation technique. The target conformal irradiation technique is a multiple non-opposed beams one isocenter technique developed to protect the heart and lungs. This technique, consisting of several rotation beams modulated with wedge filters and individual lung absorbers as well as additional fixed beams, was used in our study to apply a homogeneous dose of 46 to 56 Gy to the target volume; the irradiation technique was optimized by means of dose-volume histograms. After pre-localization, the patients underwent computerized tomographic scanning, with sections at 1.0 cm intervals. Contouring of target volume and organs at risk was carried out with a MULTIDATA workstation for regions of interest (mammarial internal and/or axillary and/or supraclavicular lymphatics and the breast or chest wall) as well as the organs at risk, such as heart and lung parenchyma. Planning target volume coverage was examined by three-dimensional isodose visualization for all CT axial sections for each patient. To determine the incidence of acute or late side effects on the lung parenchyma, conventional chest x-rays and CT studies were carried out at 1 month, 3 months and 6 months after completion of radiotherapy. Dose-volume histogram analysis revealed that this irradiation technique permits the application of a homogeneous dose to the target volume, conforming to the ICRU norms. The maximum dose applied to the ipsilateral lung parenchyma was less than 50

  1. Mitochondrial-targeted human catalase affords neuroprotection from proton irradiation.

    Science.gov (United States)

    Liao, Alicia C; Craver, Brianna M; Tseng, Bertrand P; Tran, Katherine K; Parihar, Vipan K; Acharya, Munjal M; Limoli, Charles L

    2013-07-01

    Significant past work has linked radiation exposure of the CNS to elevated levels of oxidative stress and inflammation. These secondary reactive processes are both dynamic and persistent and are believed to compromise the functionality of the CNS, in part, by disrupting endogenous neurogenesis in the hippocampus. While evidence has shown neurogenesis to be sensitive to irradiation and redox state, the mechanistic basis underlying these effects is incompletely understood. To clarify the role of reactive oxygen species (ROS) in mediating radiation-induced changes in neurogenesis we have analyzed transgenic mice that overexpress human catalase localized to the mitochondria. With this model, we investigated the consequences of low dose and clinically relevant proton irradiation on neurogenesis, and how that process is modified in response to genetic disruption of mitochondrial ROS levels. In unirradiated animals, basal neurogenesis was improved significantly by reductions in mitochondrial ROS. In animals subjected to proton exposure, hippocampal progenitor cell proliferation was attenuated significantly by overexpression of human catalase in the mitochondria. Furthermore, expression of the MCAT transgene significantly improved neurogenesis in WT animals after low-dose proton exposure (0.5 Gy), with similar trends observed at higher dose (2 Gy). Our report documents for the first time the impact of proton irradiation on hippocampal neurogenesis, and the neuroprotective properties of reducing mitochondrial ROS through the targeted overexpression of catalase. © 2013 by Radiation Research Society

  2. The development of uranium foil farication technology utilizing twin roll method for Mo-99 irradiation target

    CERN Document Server

    Kim, C K; Park, H D

    2002-01-01

    MDS Nordion in Canada, occupying about 75% of global supply of Mo-99 isotope, has provided the irradiation target of Mo-99 using the rod-type UAl sub x alloys with HEU(High Enrichment Uranium). ANL (Argonne National Laboratory) through co-operation with BATAN in Indonesia, leading RERTR (Reduced Enrichment for Research and Test Reactors) program substantially for nuclear non-proliferation, has designed and fabricated the annular cylinder of uranium targets, and successfully performed irradiation test, in order to develop the fabrication technology of fission Mo-99 using LEU(Low Enrichment Uranium). As the uranium foils could be fabricated in laboratory scale, not in commercialized scale by hot rolling method due to significant problems in foil quality, productivity and economic efficiency, attention has shifted to the development of new technology. Under these circumstances, the invention of uranium foil fabrication technology utilizing twin-roll casting method in KAERI is found to be able to fabricate LEU or...

  3. Target and structural materials under dual-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Camus, E.; Wanderka, N.; Wollenberger, H. [Hahn-Meitner-Institut Berlin GmbH (Germany)

    1995-11-01

    The European Spallation Source (ESS) is planned to have a beam power of 5 MW (3.75 mA of 1.334 GeV protons). This is by a factor 30 higher than the available most powerful spallation source ISIS at Rutherford-Appleton Lab. (RAL) in Great-Britain. This causes a damage rate of approx. 10 dpa (displacements per atom) per month in target materials (W or Ta) or structural materials. The problem of radiation damage by high energy protons in different alloys has been recently reviewed. At HMI, simulation irradiation using heavy ions and helium or hydrogen ions at the dual-beam facility are being out. Here, we report on some preliminary results obtained on tantalum as target material and on ferritic/martensitic steels (HT9 type steels or comparable steels), which are proposed to be used as structural materials. Goal of these investigations is to correlate the results with those obtained at spallation irradiated specimens and to investigate the unexplored field of simultaneous production of damage, helium and hydrogen at high levels. (author) 4 figs., 1 tab., 9 refs.

  4. Particle therapy of moving targets-the strategies for tumour motion monitoring and moving targets irradiation.

    Science.gov (United States)

    Kubiak, Tomasz

    2016-10-01

    Particle therapy of moving targets is still a great challenge. The motion of organs situated in the thorax and abdomen strongly affects the precision of proton and carbon ion radiotherapy. The motion is responsible for not only the dislocation of the tumour but also the alterations in the internal density along the beam path, which influence the range of particle beams. Furthermore, in case of pencil beam scanning, there is an interference between the target movement and dynamic beam delivery. This review presents the strategies for tumour motion monitoring and moving target irradiation in the context of hadron therapy. Methods enabling the direct determination of tumour position (fluoroscopic imaging of implanted radio-opaque fiducial markers, electromagnetic detection of inserted transponders and ultrasonic tumour localization systems) are presented. Attention is also drawn to the techniques which use external surrogate motion for an indirect estimation of target displacement during irradiation. The role of respiratory-correlated CT [four-dimensional CT (4DCT)] in the determination of motion pattern prior to the particle treatment is also considered. An essential part of the article is the review of the main approaches to moving target irradiation in hadron therapy: gating, rescanning (repainting), gated rescanning and tumour tracking. The advantages, drawbacks and development trends of these methods are discussed. The new accelerators, called "cyclinacs", are presented, because their application to particle therapy will allow making a breakthrough in the 4D spot scanning treatment of moving organs.

  5. Crystallographic changes in lead zirconate titanate due to neutron irradiation

    Directory of Open Access Journals (Sweden)

    Alexandra Henriques

    2014-11-01

    Full Text Available Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method is used to quantify the type and extent of structural changes in PbZr0.5Ti0.5O3 after exposure to a 1 MeV equivalent neutron fluence of 1.7 × 1015 neutrons/cm2. The results show a measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the effects of radiation on crystallographic structure may be investigated.

  6. Materials characterization of irradiated spectralon from the NIF target chamber

    Science.gov (United States)

    Chow, Robert; Frieders, Gene; Jensen, Wayne; Pearson, Mark; Datte, Phil

    2015-08-01

    The Near Backscatter Imager (NBI) participates in nearly every kind of experiment conducted at NIF and measures backscatter, the result of the interaction between incident laser light and plasma waves at a target. Large Spectralon plates, on the order of a hundreds of mm per side, are used as Lambertian scatter components for the NBI diagnostics. The plates were deployed in 2009 and replaced in April of 2014. All NBI assemblies suffered reflectivity degradation, and some of these changes were spatially localized defects observed after irradiation to a cumulative combined neutron and Υ dose of 0.038 Gy. The growth of a defect was correlated to the combined cumulative neutron and Υ radiation dose from NIF fusion shots. Spectralon plates that were irradiated to cumulative combined neutron and Υ dose of 0.74 Gy were characterized for materials and mechanical changes with the following techniques: RBS, FTIR, XPS, SEM, EDX and tensile tests. These tests indicate that the bulk Spectralon did not measurably degrade but there are discolorations that affect the reflectivity. Surface analysis indicates that the surface CF2 species re-forms to make various organic and CFx species.

  7. Selection of flowing liquid lead target structural materials for accelerator driven transmutation applications

    Science.gov (United States)

    Park, John J.; Buksa, John J.

    1995-09-01

    The beam entry window and container for a liquid lead spallation target will be exposed to high fluxes of protons and neutrons that are both higher in magnitude and energy than have been experienced in proton accelerators and fission reactors, as well as in a corrosive environment. The structural material of the target should have a good compatibility with liquid lead, a sufficient mechanical strength at elevated temperatures, a good performance under an intense irradiation environment, and a low neutron absorption cross section; these factors have been used to rank the applicability of a wide range of materials for structural containment. Nb-1Zr has been selected for use as the structural container for the LANL ABC/ATW molten lead target. Corrosion and mass transfer behavior for various candidate structural materials in liquid lead are reviewed, together with the beneficial effects of inhibitors and various coatings to protect substrate against liquid lead corrosion. Mechanical properties of some candidate materials at elevated temperatures and the property changes resulting from 800 MeV proton irradiation are also reviewed.

  8. Post-irradiation analysis of the tantalum container of an ISOLDE LBE target

    CERN Document Server

    Noah, E; Bruetsch, R; Catherall, R; Gavillet, D; Krbanjevic, J; Linder, H P; Martin, M; Neuhausen, J; Schumann, D; Stora, T; Zanini, L

    2012-01-01

    CERN-ISOLDE operates a range of oxides, carbides, refractory metal foils and liquid metal targets for the production of radioactive ion beams. Following irradiation with a pulsed beam of 1 GeV and 1.4 GeV protons at temperatures reaching 600 degrees C, the tantalum container of a liquid lead bismuth eutectic (LBE) target was examined. A thin layer of Pb/Bi was observed on the inner surface of the container. A sample of the surface prepared using the focused ion beam technique was investigated using SEM and EDX. Results show a higher concentration of bismuth at the interface with tantalum and micron-sized cracks in the tantalum filled with LBE. Implications of these results for the lifetime of the target container which has been known to fail under pulsed beam operation are discussed. (C) 2011 Elsevier B.V. All rights reserved.

  9. Physics of Double Pulse Irradiation of Targets For Proton Acceleration

    Science.gov (United States)

    Kerr, S.; Mo, M.; Masud, R.; Manzoor, L.; Tiedje, H.; Tsui, Y.; Fedosejevs, R.; Link, A.; Patel, P.; McLean, H.; Hazi, A.; Chen, H.; Ceurvorst, L.; Norreys, P.

    2016-10-01

    Experiments have been carried out on double-pulse irradiation of um-scale foil targets with varying preplasma conditions. Our experiment at the Titan Laser facility utilized two 700 fs, 1054 nm pulses, separated by 1 to 5 ps with a total energy of 100 J, and with 5-20% of the total energy contained within the first pulse. The proton spectra were measured with radiochromic film stacks and magnetic spectrometers. The prepulse energy was on the order of 10 mJ, which appears to have a moderating effect on the double pulse enhancement of proton beam. We have performed LSP PIC simulations to understand the double pulse enhancement mechanism, as well as the role of preplasma in modifying the interaction. A 1D parameter study was done to isolate various aspects of the interaction, while 2D simulations provide more detailed physical insight and a better comparison with experimental data. Work by the Univ. of Alberta was supported by the Natural Sciences and Engineering Research Council of Canada. Work by LLNL was performed under the auspices of U.S. DOE under contract DE-AC52-07NA27344.

  10. Suppressor T cells - a sensitive target of lead toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Hambach, A.; Stiller-Winkler, R.; Oberbarnscheidt, J.; Ewers, J.

    1983-01-01

    Studies were performed to investigate the effect of chronic low level lead exposure on the regulatory functions of T cells in the humoral immune response to sheep red blood cells (SRBC) in mice. Female mice were exposed to lead (as lead acetate) in the diet at 545 (group 1) and 2180 ppm (group 2) for 10 weeks. Lead exposure resulting in blood lead levels (PbB) of about 50 ..mu..g/100 g (group 1) produced a substantial increase of the number of IgG antibodies secreting spleen cells on days 3 and 4 after challenge. At the higher exposure level (group 2; PbB 60-80 ..mu..g/100 g) a suppression of the number of IgG plaque forming cells was observed. The IgM response was much smaller than the IgG response. Although differences between the group means were small, the results indicate that there also is an enhancement of the IgM response in the lower dosage group on days 3 and 4. In a second experiment the effect of in vivo lead exposure on antigenic competition was examined. Lead substantially reduced the effect of antigenic competition. Results of both experiments suggest that suppressor T cells rather than helper T cells may represent the primary target for lead. Throughout this study serum complement C3 levels were determined. Complement C3 levels tended to be reduced in the lead exposed groups before as well as after inocculation with SRBC. (orig.*.

  11. Suppressor T cells - a sensitive target of lead toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Hambach, A.; Stiller-Winkler, R.; Oberbarnscheidt, J.; Ewers, U.

    1983-01-01

    Studies were performed to investigate the effect of chronic low level lead exposure on the regulatory functions of T cells in the humoral immune response to sheep red blood cells (SRBC) in mice. Female mice were exposed to lead (as lead acetate) in the diet at 545 (group 1) and 2180 ppm (group 2) for 10 weeks. Lead exposure resulting in blood lead levels (PbB) of about 50 ..mu..g/100 g (group 1) produced a substantial increase of the number of IgG antibodies secreting spleen cells on days 3 and 4 after challenge. At the higher exposure level (group 2; PbB 60-80 ..mu..m/100 g) a suppression of the number of IgG plawue forming cells was observed. The IgM response was much smaller than the IgG response. Although differences between the group means were small, the results indicate that there also is an enhancement of the IgM response in the lower dosage group on days 3 and 4. In a second experiment the effect of in vivo lead exposure on antigenic competition was examined. Lead substantially reduced the effect of antigenic competition. Results of both experiments suggest that suppressor T cells rather than helper T cells may represent the primary target for lead. Throughout this study serum complement C3 levels were determined. Complement C3 levels tended to be reduced in the lead exposed groups before as well as after inocculation with SRBC.

  12. Adsorption of Lead Ions from Aqueous Solutions Using Gamma Irradiated Minerals

    Directory of Open Access Journals (Sweden)

    Julián Cruz-Olivares

    2016-01-01

    Full Text Available For the first time, an irradiated mineral was used as a novel modified adsorbent for lead removal of aqueous solutions. The effects of gamma radiation doses and temperature on the lead adsorption capacity of an unknown mineral were evaluated. The results show that, in the chemisorption process, the highest adsorption capacity (9.91 mg/g and the maximum percentage of lead removal (99.1% were reached at 40°C when using an irradiated mineral at 150 kGy. The improvement on the lead adsorption speed was the most important feature of the irradiated mineral. The experimental results were successfully correlated with the pseudo second-order kinetic model. For all results, the average absolute relative deviations (AARD were less than 13.20%, and the correlation factor (r2 was higher than 0.998. Moreover, the average values of the thermodynamic parameters (ΔG0=-10612 J/mol, ΔH0=-12360 J/mol, and ΔS0=171 J/mol K suggest the feasibility of the proposed process, in terms of the endothermic and irreversible chemisorption results; moreover, ion exchange was evaluated through the EDS results. The X-ray diffraction analysis showed that the unknown irradiated mineral is mainly composed of quartz (SiO2, calcite (CaCO3, and calcium magnesium silicate (Ca0.15Mg0.85 Mg (SiO6.

  13. Investigation of heat release in the targets during irradiation by ion beams

    CERN Document Server

    Dalkarov, O D; Rusetskii, A S

    2015-01-01

    The DD-reaction is investigated and the heat emission off the targets during their irradiation with ion beams is studied at the HELIS ion accelerator at LPI. The heat emission is observed to be significantly higher in the case of irradiation of the Ti/TiO2:Dx-targets by a D+ beam, as compared to the H+ and Ne+ beams. Furthermore, it depends on the concentration of deuterium in the target and current density of the deuteron beam.

  14. Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

    Energy Technology Data Exchange (ETDEWEB)

    Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J. [Paris-11 Univ., 91- Orsay (France). Inst. de Physique Nucleaire; Enqvist, T.; Armbruster, P.; Ricciardi, M.V.; Schmidt, K.H. [GSI, Planckstrasse 1, Darmstadt (Germany); Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91 - Gif sur Yvette (France); Benlliure, J.; Casajeros, E.; Pereira, J. [University of Santiago de Compostella (Spain); Czajkowski, S. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, CNRS-IN2P3, 33 - Gradignan (France)

    2001-07-01

    The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

  15. IDMap: facilitating the detection of potential leads with therapeutic targets.

    Science.gov (United States)

    Ha, Soyang; Seo, Young-Ju; Kwon, Min-Seok; Chang, Byung-Ha; Han, Cheol-Kyu; Yoon, Jeong-Hyeok

    2008-06-01

    Pharmaceutical industry has been striving to reduce the costs of drug development and increase productivity. Among the many different attempts, drug repositioning (retargeting existing drugs) comes into the spotlight because of its financial efficiency. We introduce IDMap which predicts novel relationships between targets and chemicals and thus is capable of repositioning the marketed drugs by using text mining and chemical structure information. Also capable of mapping commercial chemicals to possible drug targets and vice versa, IDMap creates convenient environments for identifying the potential lead and its targets, especially in the field of drug repositioning. IDMap executable and its user manual including color images are freely available to non-commercial users at http://www.equispharm.com/idmap

  16. Use of Lead (II) Sulfide Nanoparticles as Stabilizer for PMMA Exposed to Gamma Irradiation

    OpenAIRE

    Garcia,Olga Pinheiro; Albuquerque,Marília Cordeiro Carneiro de; Aquino, Kátia Aparecida da Silva; Araujo,Patricia Lopes Barros; Araujo,Elmo Silvano de

    2015-01-01

    Lead (II) sulfide (PbS) were synthesized by sonochemical method and crystals with cubic structure exhibit aggregated nanoparticles with size in the range of 50-100 nm. Commercial Poly(methyl methacrylate) (PMMA) containing the PbS nanoparticles (PbS-NP) exposed to gamma irradiation were investigated and both the viscosity-average molar mass (Mv) and degradation index (DI) values were measured. Ours results showed decreases in molar mass when the systems were gamma irradiated, i. e., random sc...

  17. Radiation-Induced Centers in Lead Silicate Glasses Irradiated by Stationary and Pulsed Electron Beams

    Science.gov (United States)

    Zhidkov, I. S.; Zatsepin, A. F.; Konev, S. F.; Cholakh, S. O.

    2015-08-01

    Radiation-induced centers formed in heavy flint glasses irradiated by electron beams are investigated by the methods of optical and EPR spectroscopy. It is revealed that stable and short-living optical absorption centers of close natures are formed under irradiation by fast electrons. A correlation is established between the stable optical absorption bands and the EPR signals interpreted as signals of the (Pb2+)/h+ hole centers. The shortliving color centers are formed due to short-term distortion of the O-Pb bonds, and the stable centers are formed due to the spatial separation, thermalization, and subsequent stabilization of excited electrons and holes in tails of the localized states. Irradiation by electron beams leads to a change in the spectral characteristics of the fundamental absorption edge and, in particular, of the Urbach energy that determines the degree of structural disorder.

  18. Determination of the accuracy for targeted irradiations of cellular substructures at SNAKE

    Energy Technology Data Exchange (ETDEWEB)

    Siebenwirth, C. [Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Greubel, C. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Drexler, S.E. [Department of Radiation Oncology, Ludwig-Maximilians-Universität München, Munich (Germany); Girst, S.; Reindl, J. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Walsh, D.W.M. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Department of Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Munich (Germany); Dollinger, G. [Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg (Germany); Friedl, A.A. [Department of Radiation Oncology, Ludwig-Maximilians-Universität München, Munich (Germany); and others

    2015-04-01

    In the last 10 years the ion microbeam SNAKE, installed at the Munich 14 MV tandem accelerator, has been successfully used for radiobiological experiments by utilizing pattern irradiation without targeting single cells. Now for targeted irradiation of cellular substructures a precise irradiation device was added to the live cell irradiation setup at SNAKE. It combines a sub-micrometer single ion irradiation facility with a high resolution optical fluorescence microscope. Most systematic errors can be reduced or avoided by using the same light path in the microscope for beam spot verification as well as for and target recognition. In addition online observation of the induced cellular responses is possible. The optical microscope and the beam delivering system are controlled by an in-house developed software which integrates the open-source image analysis software, CellProfiler, for semi-automatic target recognition. In this work the targeting accuracy was determined by irradiation of a cross pattern with 55 MeV carbon ions on nucleoli in U2OS and HeLa cells stably expressing a GFP-tagged repair protein MDC1. For target recognition, nuclei were stained with Draq5 and nucleoli were stained with Syto80 or Syto83. The damage response was determined by live-cell imaging of MDC1-GFP accumulation directly after irradiation. No systematic displacement and a random distribution of about 0.7 μm (SD) in x-direction and 0.8 μm (SD) in y-direction were observed. An independent analysis after immunofluorescence staining of the DNA damage marker yH2AX yielded similar results. With this performance a target with a size similar to that of nucleoli (i.e. a diameter of about 3 μm) is hit with a probability of more than 80%, which enables the investigation of the radiation response of cellular subcompartments after targeted ion irradiation in the future.

  19. Modeling of fast phase transitions dynamics in metal target irradiated by pico- and femtosecond pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Mazhukin, V.I. [Institute of Mathematical Modeling, Russian Academy of Sciences, Miusskaya sq. 4A, 125047 Moscow (Russian Federation); Lobok, M.G. [Institute of Mathematical Modeling, Russian Academy of Sciences, Miusskaya sq. 4A, 125047 Moscow (Russian Federation)], E-mail: immras@orc.ru; Chichkov, B. [Laser Zentrum Hannover e.V. Holleritallee 8, 30419 Hannover (Germany)], E-mail: b.chichkov@lhz.de

    2009-03-01

    We investigate laser pulse influence on aluminum target in irradiance range 10{sup 9} to 10{sup 16} W/cm{sup 2}, pulse duration between 10{sup -8} and 10{sup -15} s, Gaussian time profile with wavelength of 0.8 {mu}m. For all computations energy density was 10 J/cm{sup 2}. Plasma in the evaporated material is generated at the energy density above 10 J/cm{sup 2}as the modeling showed. Long and short laser pulses distinguish by the mechanisms of energy transformation. For short laser pulses there is volumetric energy absorption, together with rapid phase transitions it lead to overheating in solid and liquid states, overheated solid temperature rises up to (6-8)T{sub m}. Under influence of the energy saved in overheated solid, duration of the phase transitions becomes nanosecond, which is several orders of magnitude longer than laser pulse.

  20. Lead-bismuth eutectic recrystallization studies for the Megapie target

    Energy Technology Data Exchange (ETDEWEB)

    Zucchini, A. [ENEA, FIS/MET, Centro Ricerche ' E.Clementel' , via Don Fiammelli 2, 40128 Bologna (Italy); Agostini, P. [ENEA, FIS/ING, Centro Ricerche Brasimone, 40032 Camugnano, Bologna (Italy); Baicchi, E. [ENEA, FIS/ING, Centro Ricerche Brasimone, 40032 Camugnano (Bologna) (Italy)]. E-mail: elio.baicchi@brasimone.enea.it

    2005-02-01

    The expansion behaviour after freezing of the lead-bismuth eutectic (LBE) with 44.5% lead and 55.5% bismuth is described according to the reported theory. The issue of the vessel structural integrity after LBE recrystallization was dealt with by experimental and numerical studies performed in the frame of the Megapie (Megawatt Pilot Experiment) project. We have identified the important elements which, in the case of LBE solidification inside the Megapie target, play a role in the reduction of the possible vessel over-stressing; among them, the LBE yield strength has been tested under significant experimental conditions. The resulting suggestions can also be related to the design and to the freezing procedures for other LBE technology facilities.

  1. 90° Neutron emission from high energy protons and lead ions on a thin lead target

    Science.gov (United States)

    Agosteo, S.; Birattari, C.; Foglio Para, A.; Mitaroff, A.; Silari, M.; Ulrici, L.

    2002-01-01

    The neutron emission from a relatively thin lead target bombarded by beams of high energy protons/pions and lead ions was measured at CERN in one of the secondary beam lines of the Super Proton Synchrotron for radiation protection and shielding calculations. Measurements were performed with three different beams: 208Pb 82+ lead ions at 40 GeV/ c per nucleon and 158 GeV/ c per nucleon, and 40 GeV/ c mixed protons/pions. The neutron yield and spectral fluence per incident ion on target were measured at 90° with respect to beam direction. Monte-Carlo simulations with the FLUKA code were performed for the case of protons and pions and the results found in good agreement with the experimental data. A comparison between simulations and experiment for protons, pions and lead ions have shown that—for such high energy heavy ion beams—a reasonable estimate can be carried out by scaling the result of a Monte-Carlo calculation for protons by the projectile mass number to the power of 0.80-0.84.

  2. Heavy-Ion Irradiation of Thulium(III) Oxide Targets Prepared by Polymer-Assisted Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, Tashi; Ashby, Paul D.; Gates, Jacklyn M.; Stavsetra, Liv; Gregorich, Kenneth E.; Nitsche, Heino

    2008-09-15

    Thulium(III) oxide (Tm{sub 2}O{sub 3}) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method's feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 {micro}g/cm{sup 2}) and were irradiated with an {sup 40}Ar beam at laboratory frame energy of {approx}210 MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1 nm for a {approx}250 nm ({approx}220 {micro}g/cm{sup 2}) Tm{sub 2}O{sub 3} target, and an RMS roughness of 2.0 nm after irradiation was measured by atomic force microscopy (AFM). Scanning electron microscopy of the irradiated target reveals no significant differences in surface homogeneity when compared to imaging prior to irradiation. Target flaking was not observed from monitoring Rutherford scattered particles as a function of time.

  3. 77 FR 16796 - Lead Requirements for Lead-Based Paint Activities in Target Housing and Child-Occupied Facilities...

    Science.gov (United States)

    2012-03-22

    ... AGENCY 40 CFR Part 745 Lead Requirements for Lead-Based Paint Activities in Target Housing and Child... requirements, training program accreditation requirements, and work practice standards for lead-based paint... the Arkansas lead-based paint program and passed a new statute establishing a State lead-based paint...

  4. Nonequilibrium self-organization in alloys under irradiation leading to the formation of nano composites

    CERN Document Server

    Enrique, R A; Averback, R S; Bellon, P

    2003-01-01

    Alloys under irradiation are continuously driven away from equilibrium: Every time an external particle interacts with the atoms in the solid, a perturbation very localized in space and time is produced. Under this external forcing, phase and microstructural evolution depends ultimately on the dynamical interaction between the external perturbation and the internal recovery kinetics of the alloy. We consider the nonequilibrium steady state of an immiscible binary alloy subject to mixing by heavy-ion irradiation. It has been found that the range of the forced atomic relocations taking place during collision cascades plays an important role on the final microstructure: when this range is large enough, it can lead to the spontaneous formation of compositional patterns at the nanometer scale. These results were rationalized in the framework of a continuum model solved by deriving a nonequilibrium thermodynamic potential. Here we derive the nonequilibrium structure factor by including the role of fluctuations. In ...

  5. Polonium problem in lead-bismuth flow target

    Energy Technology Data Exchange (ETDEWEB)

    Pankratov, D.V.; Yefimov, E.I.; Bugreev, M.I. [State Scientific Centre of Russian Federation-Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1996-06-01

    Alpha-active polonium nuclides Po198 - Po210 are formed in a lead-bismuth target as results of reactions Bi{sup 209}(n,{gamma})Bi{sup 210} {yields} Po{sup 210}, Bi{sup 209}(p,xn)Po{sup 210} {yields} Po{sup 210 {minus} x} (x = 1-12), Pb{sup 208}({alpha},xn) {yields} Po{sup 210 {minus} x + 2} (x = 2-14). The most important nuclides are Po-210 (T{sub {1/2}}=138.4 day), Po-209 (T{sub {1/2}}=102 years) and Po-208 (T{sub {1/2}}=2.9 years). Polonium activity of the circuit for SINQ - conditions is about 15,000 Ci after 1-year operation. Polonium radiation hazard is connected with its output from the coolant and formation of aerosol and surface alpha-activity after the circuit break-down for repair works or in accidents. One of the important issues of polonium removal system creation is containing and storing polonium removed. Its storage in solidified alkaline is not expedient because of secondary neutron formation as a result of ({alpha},n) - reaction on oxygen and sodium nucleus. The estimations carried out demonstrated that by polonium concentration {approx} 100 Ci/l neutron current on the container surface can reach {approx} 10{sup 4}n/(cm{sup 2}s). Concentration and storage of polonium in solidified lead-bisumth seems the most convenient. The calculations demonstrated that in a 100 l container 50,000 Ci of polonium can be stored (as much as 3 times more than 1-year polonium product in SINQ-conditions) under temperature in the container less than melting point of lead bismuth (the wall temperature is about 100{degrees}C).

  6. Measurement of Volatile Radionuclides Production and Release Yields followed by a Post-Irradiation Analysis of a Pb/Bi Filled Ta Target at ISOLDE

    Science.gov (United States)

    Zanini, L.; Köster, U.; David, J. C.; Tall, Y.; Andersson, M.; Berg, K.; Cormon, S.; Fallot, M.; Foucher, Y.; Frånberg, H.; Gröschel, F.; Guertin, A.; Kirchner, T.; Leray, S.; Manfrin, E.; Noah, E.; Ravn, H.; Stora, T.; Thiollière, N.; Wohlmuther, M.

    2014-05-01

    A crucial requirement in the development of liquid-metal spallation neutron target is knowledge of the composition and amount of volatile radionuclides that are released from the target during operation. It is also important to know the total amount produced, which could be released if there was an accident. One type is the lead-bismuth eutectic (LBE) target where different radionuclides can be produced following interaction with a high-energy proton beam, notably noble gases (Ar, Kr, Xe isotopes) and other relative volatile isotopes such as Hg and At. The results of an irradiation experiment performed at ISOLDE on a LBE target are compared with predictions from the MCNPX code using the latest developments on the Liège Intranuclear Cascade model (INCL4.6) and the CEM03 model. The calculations are able to reproduce the mass distribution of the radioisotopes produced, including the At production, where there is a significant contribution from secondary reactions. Subsequently, a post-irradiation examination of the irradiated target was performed. Investigations of both the tantalum target structure, in particular the beam window, and the lead-bismuth eutectic were performed using several experimental techniques. No sign of severe irradiation damage, previously observed in other ISOLDE targets, was found.

  7. Accumulation of color centers in lithium fluoride crystals under irradiation with swift lead projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Benhacine, H. [LRPCSI, University of 20 Août 1955 Skikda, Route El-Hadaeik, 21000 Skikda (Algeria); Département de physique Université Constantine 1, Route Ain El-Bey 25000 (Algeria); Sorokin, M.V., E-mail: m40@lab2.ru [National Research Centre ‘Kurchatov Institute’, Kurchatov Square 1, 123182 Moscow (Russian Federation); Schwartz, K. [GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Meftah, A. [LRPCSI, University of 20 Août 1955 Skikda, Route El-Hadaeik, 21000 Skikda (Algeria)

    2015-09-15

    Lithium fluoride crystals were irradiated with lead ions of different energies, having the electronic energy loss of 10–20 keV/nm. Accumulation of F centers with fluence was studied by absorption UV–VIS spectroscopy. It was found that the average F-center concentration is mainly determined by the average absorbed energy density with a weak decrease above 10{sup 23} eV/cm{sup 3}. A defect accumulation model, taking into account the recombination processes, is proposed for a seamless description of the F-center concentration fluence dependences for various projectiles and energy losses.

  8. Structural investigations of bismuth lead borosilicate glasses under the influence of gamma irradiation through ultrasonic studies

    Science.gov (United States)

    Bootjomchai, Cherdsak; Laopaiboon, Jintana; Laopaiboon, Raewat

    2012-04-01

    The ultrasonic velocity measurements for different compositions of irradiated bismuth lead borosilicate glasses xBi2O3-(50-x)PbO-20B2O3-30SiO2 (x=2, 4, 6, 8, and 10 mol.%) were performed at room temperature using pulse-echo technique. Densities of glass samples were measured by Archimedes' principle using n-hexane as the immersion liquid. The results from the studies show that ultrasonic velocity, elastic moduli, Poisson's ratio, microhardness, and the Debye temperature increase with increasing bismuth oxide content and increasing gamma-radiation dose (3-12 Gy).

  9. Shock dynamics induced by double-spot laser irradiation of layered targets

    Directory of Open Access Journals (Sweden)

    Aliverdiev Abutrab A.

    2015-06-01

    Full Text Available We studied the interaction of a double-spot laser beam with targets using the Prague Asterix Laser System (PALS iodine laser working at 0.44 μm wavelength and intensity of about 1015 W/cm2. Shock breakout signals were recorder using time-resolved self-emission from target rear side of irradiated targets. We compared the behavior of pure Al targets and of targets with a foam layer on the laser side. Results have been simulated using hydrodynamic numerical codes.

  10. Systems and methods for processing irradiation targets through a nuclear reactor

    Science.gov (United States)

    Dayal, Yogeshwar; Saito, Earl F.; Berger, John F.; Brittingham, Martin W.; Morales, Stephen K.; Hare, Jeffrey M.

    2016-05-03

    Apparatuses and methods produce radioisotopes in instrumentation tubes of operating commercial nuclear reactors. Irradiation targets may be inserted and removed from instrumentation tubes during operation and converted to radioisotopes otherwise unavailable during operation of commercial nuclear reactors. Example apparatuses may continuously insert, remove, and store irradiation targets to be converted to useable radioisotopes or other desired materials at several different origin and termination points accessible outside an access barrier such as a containment building, drywell wall, or other access restriction preventing access to instrumentation tubes during operation of the nuclear plant.

  11. Wollastonite based-Chemically Bonded Phosphate Ceramics with lead oxide contents under gamma irradiation

    Science.gov (United States)

    Colorado, H. A.; Pleitt, J.; Hiel, C.; Yang, J. M.; Hahn, H. T.; Castano, C. H.

    2012-06-01

    The shielding properties to gamma rays as well as the effect of lead concentration incorporated into Chemically Bonded Phosphate Ceramics (CBPCs) composites are presented. The Wollastonite-based CBPC was fabricated by mixing a patented aqueous phosphoric acid formulation with Wollastonite powder. CBPC has been proved to be good structural material, with excellent thermal resistant properties, and research already showed their potential for radiation shielding applications. Wollastonite-based CBPC is a composite material itself with several crystalline and amorphous phases. Irradiation experiments were conducted on different Wollastonite-based CBPCs with lead oxide. Radiation shielding potential, attenuation coefficients in a broad range of energies pertinent to engineering applications and density experiments showing the effect of the PbO additions (to improve gamma shielding capabilities) are also presented. Microstructure was identified by using scanning electron microscopy and X-ray diffraction.

  12. Vacuum heating of solid target irradiated by femtosecond laser pulses

    Institute of Scientific and Technical Information of China (English)

    DONG; Quanli(董全力); ZHANG; Jie(张杰)

    2003-01-01

    The interaction of femtosecond laser pulses with solid targets was studied through experiments and particle-in-cell (PIC) simulations. It is proved that the vacuum heating and the inverse bremsstralung process are the main mechanisms of the laser pulse absorption under such conditions. The distribution of hot electrons and that of X-ray are found to have double-temperature structure, which is confirmed by PIC simulations. While the lower temperature is attributed to the resonant absorption, the higher one, however, is caused by the laser-induced electric field in the target normal direction. The time-integrated spectra ofthe reflected laser pulse shows that the mechanism of electron acceleration is determined by the plasma density profile.

  13. Separation of Plutonium from Irradiated Fuels and Targets

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Leonard W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Holliday, Kiel S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Murray, Alice [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Thompson, Major [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Thorp, Donald T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Yarbro, Stephen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Venetz, Theodore J. [Hanford Site, Benton County, WA (United States)

    2015-09-30

    Spent nuclear fuel from power production reactors contains moderate amounts of transuranium (TRU) actinides and fission products in addition to the still slightly enriched uranium. Originally, nuclear technology was developed to chemically separate and recover fissionable plutonium from irradiated nuclear fuel for military purposes. Military plutonium separations had essentially ceased by the mid-1990s. Reprocessing, however, can serve multiple purposes, and the relative importance has changed over time. In the 1960’s the vision of the introduction of plutonium-fueled fast-neutron breeder reactors drove the civilian separation of plutonium. More recently, reprocessing has been regarded as a means to facilitate the disposal of high-level nuclear waste, and thus requires development of radically different technical approaches. In the last decade or so, the principal reason for reprocessing has shifted to spent power reactor fuel being reprocessed (1) so that unused uranium and plutonium being recycled reduce the volume, gaining some 25% to 30% more energy from the original uranium in the process and thus contributing to energy security and (2) to reduce the volume and radioactivity of the waste by recovering all long-lived actinides and fission products followed by recycling them in fast reactors where they are transmuted to short-lived fission products; this reduces the volume to about 20%, reduces the long-term radioactivity level in the high-level waste, and complicates the possibility of the plutonium being diverted from civil use – thereby increasing the proliferation resistance of the fuel cycle. In general, reprocessing schemes can be divided into two large categories: aqueous/hydrometallurgical systems, and pyrochemical/pyrometallurgical systems. Worldwide processing schemes are dominated by the aqueous (hydrometallurgical) systems. This document provides a historical review of both categories of reprocessing.

  14. The morphology of the artery of heart and aorta after combined irradiation and cadmium and lead salts treatment

    Directory of Open Access Journals (Sweden)

    Ostrovskaya S.S.

    2007-01-01

    Full Text Available The purpose of the work was to study the morphology of the heart and aorta in combined action of irradiation with cadmium and lead. 60 Vistar line male rats divided into 6 groups were used. Rats of the 1,2, and 3 groups were treated by a total single gamma-irradiation in the dose 0,5 Gr. 3 months after irradiation they were treated with 1/10 LD50 in 1 ml 0,9% NaC1 chloride cadmium (1,4 groups and lead acetate (2,5 groups intraperitoneally during 10 with following 15-day regeneration period. Rats of the 3 and 6 groups irradiated and non-irradiated (the last group was a control one were treated 1 ml 0,9% of NaC1. In 10 and 15 days the heart and portion of the aorta at the level of valves were dissected for histologic examination. Combined action of irradiation, salts of cadmium and lead causes the increase of vessel index in heart arteries, thickening of aorta walls in rats that suggest that sclerosis of arteries develops. In cadmium intoxication this process accelerates predominantly in the vessels of a small caliber, while in lead intoxication – in large vessels. In both cases this process has reversible character. Combined action of irradiation and lead, irradiation and cadmium induces progressed development of sclerosis of arteries. We conclude that accelerated development of sclerosis of arteries and the aorta is one of the manifestation of potentiating effect of a combined influence of irradiation and heavy metals.

  15. Production of medical isotopes from a thorium target irradiated by light charged particles up to 70 MeV

    Science.gov (United States)

    Duchemin, C.; Guertin, A.; Haddad, F.; Michel, N.; Métivier, V.

    2015-02-01

    The irradiation of a thorium target by light charged particles (protons and deuterons) leads to the production of several isotopes of medical interest. Direct nuclear reaction allows the production of Protactinium-230 which decays to Uranium-230 the mother nucleus of Thorium-226, a promising isotope for alpha radionuclide therapy. The fission of Thorium-232 produces fragments of interest like Molybdenum-99, Iodine-131 and Cadmium-115g. We focus our study on the production of these isotopes, performing new cross section measurements and calculating production yields. Our new sets of data are compared with the literature and the last version of the TALYS code.

  16. Production of medical isotopes from a thorium target irradiated by light charged particles up to 70 MeV.

    Science.gov (United States)

    Duchemin, C; Guertin, A; Haddad, F; Michel, N; Métivier, V

    2015-02-07

    The irradiation of a thorium target by light charged particles (protons and deuterons) leads to the production of several isotopes of medical interest. Direct nuclear reaction allows the production of Protactinium-230 which decays to Uranium-230 the mother nucleus of Thorium-226, a promising isotope for alpha radionuclide therapy. The fission of Thorium-232 produces fragments of interest like Molybdenum-99, Iodine-131 and Cadmium-115g. We focus our study on the production of these isotopes, performing new cross section measurements and calculating production yields. Our new sets of data are compared with the literature and the last version of the TALYS code.

  17. Lithium target for accelerator based BNCT neutron source: Influence by the proton irradiation on lithium

    Science.gov (United States)

    Fujii, R.; Imahori, Y.; Nakakmura, M.; Takada, M.; Kamada, S.; Hamano, T.; Hoshi, M.; Sato, H.; Itami, J.; Abe, Y.; Fuse, M.

    2012-12-01

    The neutron source for Boron Neutron Capture Therapy (BNCT) is in the transition stage from nuclear reactor to accelerator based neutron source. Generation of low energy neutron can be achieved by 7Li (p, n) 7Be reaction using accelerator based neutron source. Development of small-scale and safe neutron source is within reach. The melting point of lithium that is used for the target is low, and durability is questioned for an extended use at a high current proton beam. In order to test its durability, we have irradiated lithium with proton beam at the same level as the actual current density, and found no deterioration after 3 hours of continuous irradiation. As a result, it is suggested that lithium target can withstand proton irradiation at high current, confirming suitability as accelerator based neutron source for BNCT.

  18. Study of intense pulse irradiation effects on silicon targets considered as ground matter for optical detectors; Etude des effets d`irradiations pulsees intenses sur des cibles de silicium considere en tant que materiau de base pour detecteurs optiques

    Energy Technology Data Exchange (ETDEWEB)

    Muller, O.

    1994-12-01

    This study aim was centered on morphological and structural alterations induced by laser irradiation on silicon targets considered as ground matter for optical detectors. First we recalled the main high light intensity effects on the condensed matter. Then we presented the experimental aspects. The experimental studies were achieved on two sample types: SiO{sub 2}/Si and Si. Two topics were studied: the defect chronology according to wavelength and pulse length, and the crystalline quality as well as the structure defects of irradiated zones by Raman spectroscopy. Finally, irradiation of Si targets by intense pulsed beams may lead to material fusion. This phenomenon is particularly easy when the material is absorbent, when the pulse is short and when the material is superficially oxidized. (MML). 204 refs., 93 figs., 21 tabs., 1 appendix.

  19. Validation of a new design of tellurium dioide-irradiated target

    Energy Technology Data Exchange (ETDEWEB)

    Fllaoui, Aziz; Ghamad, Younes; Zoubir, Brahim; Ayaz, Zinel Abidine; El Morabiti, Aissam; Amayoud, Hafid [Centre National de l' Energie des Sciences et des Techniques Nucleaires, Rabat (Morocco); Chakir, El Mahjoub [Nuclear Physics Department, University Ibn Toufail, Kenitra (Morocco)

    2016-10-15

    Production of iodine-131 by neutron activation of tellurium in tellurium dioxide (TeO{sub 2}) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gas welding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ≤ 10 - 4 mbr.L/s, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to 600 .deg. C with the appearance of deformations on lids beyond 450 .deg. C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from 4 hours of irradiation at a power level of 0.5 MW up to 35 hours (7 h/d for 5 days a week) at 1.5 MW. The results show that the irradiated targets are

  20. Validation of a New Design of Tellurium Dioxide-Irradiated Target

    Directory of Open Access Journals (Sweden)

    Aziz Fllaoui

    2016-10-01

    Full Text Available Production of iodine-131 by neutron activation of tellurium in tellurium dioxide (TeO2 material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gas welding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ≤ 10−4 mbr.L/s, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics. To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to 600°C with the appearance of deformations on lids beyond 450°C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes—convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from 4 hours of irradiation at a power level of 0.5 MW up to 35 hours (7 h/d for 5 days a week at 1.5 MW. The results show that the irradiated targets are

  1. Use of lead (II) sulfide nanoparticles as stabilizer for PMMA exposed to gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Olga Pinheiro; Albuquerque, Marilia Cordeiro Carneiro de; Aquino, Katia Aparecida da Silva; Araujo, Elmo Silvano de, E-mail: aquino@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Araujo, Patricia Lopes Barros de [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil)

    2015-03-15

    Lead (II) sulfide (PbS) were synthesized by sonochemical method and crystals with cubic structure exhibit aggregated nanoparticles with size in the range of 50-100 nm. Commercial Poly(methyl methacrylate) (PMMA) containing the PbS nanoparticles (PbS-NP) exposed to gamma irradiation were investigated and both the viscosity-average molar mass (Mv ) and degradation index (DI) values were measured. Ours results showed decreases in molar mass when the systems were gamma irradiated, i. e., random scission effects that take place in the main chain. On the other hand, DI results showed that the addition of PbS-NP at 0.3 wt% into the PMMA matrix decreased 100% the number of main chain scissions. Results about the free radical scavenger action of the PbS-NP were obtained by use of 2,2-diphenyl-1-(2,4,6-trinitrophenyl)-hydrazyl radical (DPPH) and are discussed in this study. Analysis of infrared spectra, refraction index, mechanical, and thermal properties showed influence of the PbS-NP in the physical behavior of PMMA. (author)

  2. Neutron irradiation effects on domain wall mobility and reversibility in lead zirconate titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Joseph T. [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, Texas 78758 (United States); Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Brennecka, Geoff L.; Ihlefeld, Jon F. [Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Ferreira, Paulo [Materials Science and Engineering Program, University of Texas at Austin, Austin, Texas 78751 (United States); Small, Leo [Electronic, Optic and Nano Materials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Duquette, David [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Apblett, Christopher [Advanced Power Sources R and D Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Landsberger, Sheldon [Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, Texas 78758 (United States)

    2013-03-28

    The effects of neutron-induced damage on the ferroelectric properties of thin film lead zirconate titanate (PZT) were investigated. Two sets of PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} films of varying initial quality were irradiated in a research nuclear reactor up to a maximum 1 MeV equivalent neutron fluence of (5.16 {+-} 0.03) Multiplication-Sign 10{sup 15} cm{sup -2}. Changes in domain wall mobility and reversibility were characterized by polarization-electric field measurements, Rayleigh analysis, and analysis of first order reversal curves (FORC). With increasing fluence, extrinsic contributions to the small-signal permittivity diminished. Additionally, redistribution of irreversible hysterons towards higher coercive fields was observed accompanied by the formation of a secondary hysteron peak following exposure to high fluence levels. The changes are attributed to the radiation-induced formation of defect dipoles and other charged defects, which serve as effective domain wall pinning sites. Differences in damage accumulation rates with initial film quality were observed between the film sets suggesting a dominance of pre-irradiation microstructure on changes in macroscopic switching behavior.

  3. Gamma irradiation induced in situ synthesis of lead sulfide nanoparticles in poly(vinyl alcohol) hydrogel

    Science.gov (United States)

    Kuljanin-Jakovljević, Jadranka Ž.; Radosavljević, Aleksandra N.; Spasojević, Jelena P.; Carević, Milica V.; Mitrić, Miodrag N.; Kačarević-Popović, Zorica M.

    2017-01-01

    In this study, the nanocomposites based on semiconductor lead sulfide (PbS) nanoparticles and poly(vinyl alcohol) (PVA) were investigated. The gamma irradiation induced in situ incorporation of PbS nanoparticles in crosslinked polymer network i.e. PVA hydrogel was performed. PVA hydrogel was previously obtained also under the influence of gamma irradiation. UV-Vis absorption and X-ray diffraction measurements were employed to investigate optical and structural properties of PbS nanoparticles, respectively, and obtained results indicates the presence of nanoparticles with approximately 6 nm in diameter and face centered cubic rock-salt crystal structure. The porous morphology was confirmed by scanning electron microscopy. Swelling data revealed that investigated hydrogels (PVA and PbS-PVA nanocomposite) shows non-Fickian diffusion, indicating that both diffusion and polymer relaxation processes controlled the fluid transport. The values of diffusion coefficients have an order of magnitude 10-9 cm2/s (typical values for water diffusion in polymers) and the best fit with the experimental results showed the Etters approximation. Comparing the thermal properties of PbS-PVA xerogel nanocomposite with PVA xerogel it was observed that incorporation of PbS nanoparticles in crosslinked PVA matrix just slightly enhanced the thermal stability of nanocomposite.

  4. Characterization of advanced polymethylmethacrylate (PMMA) targets for TNSA laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L., E-mail: Lorenzo.Torrisi@unime.it [Department of Physics and Earth Science, Messina University, V.le F.S. d’Alcontres 31, 98166 S. Agata, Messina (Italy); Cutroneo, M.; Semian, V. [Nuclear Physics Institute, ASCR, 250 68 Rez (Czech Republic); Ceccio, G. [Department of Physics and Earth Science, Messina University, V.le F.S. d’Alcontres 31, 98166 S. Agata, Messina (Italy)

    2015-10-01

    Highlights: • The manuscript presents the procedure to prepare thin advanced targets based on PMMA polymer in order to obtain high ion acceleration in laser-generated plasma. • The manuscript is original for the procedures of polymer preparation and preliminary techniques used. - Abstract: Characterization of advanced micrometric foils suitable for TNSA regime were performed using optical spectroscopy, microscopy and Nd:YAG low laser intensity. Micrometric acrylic beads were produced in polymethylmethacrylate foils through complex physical and technical procedures in order to enhance the absorption coefficient in the IR region. Moreover, Au nanoparticles were embedded in the polymer in order to induce surface plasmon resonance absorption and plasma electron density enhancement. The suitably prepared polymers were investigated at low laser intensity to have evidence of their capability to absorb IR wavelength radiations and promote enhancement of the plasma temperature and density. Results indicate that the high transparence of PMMA foils can be strongly reduced by the presences of the micrometric acrylic beads and that the obtainable laser-generated plasma improves the ion acceleration when high beads density and high Au nanoparticles concentrations are employed.

  5. Post Irradiation Examination Results of the NT-02 Graphite Fins NUMI Target

    Energy Technology Data Exchange (ETDEWEB)

    Ammigan, K. [Fermilab; Hurh, P. [Fermilab; Sidorov, V. [Fermilab; Zwaska, R. [Fermilab; Asner, D. M. [PNL, Richland; Casella, Casella,A.M [PNL, Richland; Edwards, D. J. [PNL, Richland; Schemer-Kohrn, A. L. [PNL, Richland; Senor, D. J. [PNL, Richland

    2017-02-10

    The NT-02 neutrino target in the NuMI beamline at Fermilab is a 95 cm long target made up of segmented graphite fins. It is the longest running NuMI target, which operated with a 120 GeV proton beam with maximum power of 340 kW, and saw an integrated total proton on target of 6.1 1020. Over the last half of its life, gradual degradation of neutrino yield was observed until the target was replaced. The probable causes for the target performance degradation are attributed to radiation damage, possibly including cracking caused by reduction in thermal shock resistance, as well as potential localized oxidation in the heated region of the target. Understanding the long-termstructural response of target materials exposed to proton irradiation is critical as future proton accelerator sources are becoming increasingly more powerful. As a result, an autopsy of the target was carried out to facilitate post-irradiation examination of selected graphite fins. Advanced microstructural imaging and surface elemental analysis techniques were used to characterize the condition of the fins in an effort to identify degradation mechanisms, and the relevant findings are presented in this paper.

  6. Targeting metalloproteins by fragment-based lead discovery.

    Science.gov (United States)

    Johnson, Sherida; Barile, Elisa; Farina, Biancamaria; Purves, Angela; Wei, Jun; Chen, Li-Hsing; Shiryaev, Sergey; Zhang, Ziming; Rodionova, Irina; Agrawal, Arpita; Cohen, Seth M; Osterman, Andrei; Strongin, Alex; Pellecchia, Maurizio

    2011-08-01

    It has been estimated that nearly one-third of functional proteins contain a metal ion. These constitute a wide variety of possible drug targets including metalloproteinases, dehydrogenases, oxidoreductases, hydrolases, deacetylases, or many others in which the metal ion is either of catalytic or of structural nature. Despite the predominant role of a metal ion in so many classes of drug targets, current high-throughput screening techniques do not usually produce viable hits against these proteins, likely due to the lack of proper metal-binding pharmacophores in the current screening libraries. Herein, we describe a novel fragment-based drug discovery approach using a metal-targeting fragment library that is based on a variety of distinct classes of metal-binding groups designed to reliably anchor the fragments at the target's metal ions. We show that the approach can effectively identify novel, potent and selective agents that can be readily developed into metalloprotein-targeted therapeutics.

  7. Proton driven acceleration by intense laser pulses irradiating thin hydrogenated targets

    Science.gov (United States)

    Torrisi, L.; Cutroneo, M.; Cavallaro, S.; Giuffrida, L.; Andò, L.; Cirrone, P.; Bertuccio, G.; Puglisi, D.; Calcagno, L.; Verona, C.; Picciotto, A.; Krasa, J.; Margarone, D.; Velyhan, A.; Laska, L.; Krousky, E.; Pfeiffer, M.; Skala, J.; Ullschmied, J.; Wolowski, J.; Badziak, J.; Rosinski, M.; Ryc, L.; Szydlowski, A.

    2013-05-01

    The Asterix iodine laser of the PALS laboratory in Prague, operating at 1315 nm fundamental frequency, 300 ps pulse duration, 600 J maximum pulse energy and 1016 W/cm2 intensity, is employed to irradiate thin hydrogenated targets placed in high vacuum. Different metallic and polymeric targets allow to generate multi-energetic and multi-specie ion beams showing peculiar properties. The plasma obtained by the laser irradiation is monitored, in terms of properties of the emitted charge particles, by using time-of-flight techniques and Thomson parabola spectrometer (TPS). A particular attention is given to the proton beam production in terms of the maximum energy, emission yield and angular distribution as a function of the laser energy, focal position (FP), target thickness and composition.

  8. Investigation on Soft X-Ray Lasers with a Picosecond-Laser-Irradiated Gas Puff Target

    Energy Technology Data Exchange (ETDEWEB)

    Fiedorowiez, H; Bartnik, A; Jarocki, R; Rakowski, R; Dunn, J; Smith, R F; Hunter, J; Hilsen, J; Shlyaptsev, V N

    2002-10-09

    We present results of experimental studies on transient gain soft x-ray lasers with a picosecond-laser-irradiated gas puff target. The target in a form of an elongated gas sheet is formed by pulsed injection of gas through a slit nozzle using a high-pressure electromagnetic valve developed and characterized at the Institute of Optoelectronics. The x-ray laser experiments were performed at the Lawrence Livermore National Laboratory using the tabletop Compact Multipulse Terawatt (COMET) laser to irradiate argon, krypton or xenon gas puff targets. Soft x-ray lasing in neon-like argon on the 3p-3s transition at 46.9 nm and the 3d-3p transition at 45.1 nm have been demonstrated, however, no amplification for nickel-like krypton or xenon was observed. Results of the experiments are presented and discussed.

  9. Post-Irradiation Examination of 237Np Targets for 238Pu Production

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Robert Noel [ORNL; Baldwin, Charles A [ORNL; Hobbs, Randy W [ORNL; Schmidlin, Joshua E [ORNL

    2015-01-01

    Oak Ridge National Laboratory is recovering the US 238Pu production capability and the first step in the process has been to evaluate the performance of a 237Np target cermet pellet encased in an aluminum clad. The process proceeded in 3 steps; the first step was to irradiate capsules of single pellets composed of NpO2 and aluminum power to examine their shrinkage and gas release. These pellets were formed by compressing sintered NpO2 and aluminum powder in a die at high pressure followed by sintering in a vacuum furnace. Three temperatures were chosen for sintering the solution precipitated NpO2 power used for pellet fabrication. The second step was to irradiate partial targets composed of 8 pellets in a semi-prototypical arrangement at the two best performing sintering temperatures to determine which temperature gave a pellet that performed the best under the actual planned irradiation conditions. The third step was to irradiate ~50 pellets in an actual target configuration at design irradiation conditions to assess pellet shrinkage and gas release, target heat transfer, and dimensional stability. The higher sintering temperature appeared to offer the best performance after one cycle of irradiation by having the least shrinkage, thus keeping the heat transfer gap between the pellets and clad small minimizing the pellet operating temperature. The final result of the testing was a target that can meet the initial production goals, satisfy the reactor safety requirements, and can be fabricated in production quantities. The current focus of the program is to verify that the target can be remotely dissembled, the pellets dissolved, and the 238Pu recovered. Tests are being conducted to examine these concerns and to compare results to code predictions. Once the performance of the full length targets has been quantified, the pellet 237Np loading will be revisited to determine if it can be

  10. The “curved lead pathway” method to enable a single lead to reach any two intracranial targets

    Science.gov (United States)

    Ding, Chen-Yu; Yu, Liang-Hong; Lin, Yuan-Xiang; Chen, Fan; Lin, Zhang-Ya; Kang, De-Zhi

    2017-01-01

    Deep brain stimulation is an effective way to treat movement disorders, and a powerful research tool for exploring brain functions. This report proposes a “curved lead pathway” method for lead implantation, such that a single lead can reach in sequence to any two intracranial targets. A new type of stereotaxic system for implanting a curved lead to the brain of human/primates was designed, the auxiliary device needed for this method to be used in rat/mouse was fabricated and verified in rat, and the Excel algorithm used for automatically calculating the necessary parameters was implemented. This “curved lead pathway” method of lead implantation may complement the current method, make lead implantation for multiple targets more convenient, and expand the experimental techniques of brain function research.

  11. Studies on neutron production in the interaction of 7.4 GeV protons with extended lead target

    CERN Document Server

    Hashemi-Nezhad, S R; Ochs, M; Wan, J S; Schmidt, T; Langrock, E J; Vater, P; Adam, J; Bamblevskij, V P; Bradnova, V; Gelovani, L K; Kalinnikov, V K; Krivopustov, M I; Kulakov, B A; Sosnin, A N; Perelygin, V P; Pronskikh, V S; Stegailov, V I; Tsoupko-Sitnikov, V M; Modolo, G; Odoj, R; Phlippen, P W; Adloff, J C; Debeauvais, M; Zamani-Valassiadou, M; Dwivedi, K K; Wilson, B

    1999-01-01

    A cylindrical lead target of diameter 8 cm and length 20 cm was irradiated with 7.4 GeV protons along the axis of the cylinder. The lead target was surrounded with a paraffin layer of thickness 6 cm to moderate the neutrons produced in p + Pb reactions. The spatial distribution of the slow and fast neutrons on different surfaces of the moderator were determined using LR 115 2B detectors (through sup 1 sup 0 B(n,alpha) sup 7 Li reactions) and CR39 detectors (through proton recoils) respectively. Such results can be valuable in the studies and design of Accelerator Driven Subcritical Nuclear Reactors and Nuclear Waste Incinerators.

  12. Blood vessel damage correlated with irradiance for in vivo vascular targeted photodynamic therapy

    Science.gov (United States)

    Zhang, Jinde; Tan, Zou; Niu, Xiangyu; Lin, Linsheng; Lin, Huiyun; Li, Buhong

    2016-10-01

    Vascular targeted photodynamic therapy (V-PDT) has been widely utilized for the prevention or treatment of vascular-related diseases, including age-related macular degeneration, port-wine stains and prostate cancer. In order to quantitative assessment the blood vessel damage during V-PDT, nude mice were implanted with Titanium dorsal skin window chambers for in vivo V-PDT studies. For treatments, various irradiances including 50, 75, 100 and 200 mW/cm2 provided by a 532 nm semiconductor laser were performed with the same total light dose of 30 J/cm2 after the mice were intravenously injection of Rose Bengal for 25 mg/Kg body weight. Laser speckle imaging and microscope were used to monitor blood flow dynamics and vessel constriction during and after V-PDT, respectively. The V-PDT induced vessel damages between different groups were compared. The results show that significant difference in blood vessel damage was found between the lower irradiances (50, 75 and 100 mW/cm2) and higher irradiance (200 mW/cm2), and the blood vessel damage induced by V-PDT is positively correlated with irradiance. This study implies that the optimization of irradiance is required for enhancing V-PDT therapeutic efficiency.

  13. Factors leading to inflation targeting : The impact of adoption

    NARCIS (Netherlands)

    Samarina, Anna; Sturm, Jan-Egbert

    2013-01-01

    This paper examines how the analysis of inflation targeting (IT) adoption is affected by allowing for a structural change after adoption, using panel probit models for 60 countries over the period 1985-2008. Our findings suggest that there is a structural change after IT adoption. Including the post

  14. Factors leading to inflation targeting - the impact of adoption

    NARCIS (Netherlands)

    Samarina, Anna; Sturm, Jan-Egbert

    2013-01-01

    This paper examines how the analysis of inflation targeting (IT) adoption is affected by the choice of the analyzed period. We test whether country characteristics influence the decision to apply IT differently before and after its adoption, using panel probit models for 60 countries over the period

  15. Factors leading to inflation targeting - the impact of adoption

    NARCIS (Netherlands)

    Samarina, Anna; Sturm, Jan-Egbert

    2013-01-01

    This paper examines how the analysis of inflation targeting (IT) adoption is affected by the choice of the analyzed period. We test whether country characteristics influence the decision to apply IT differently before and after its adoption, using panel probit models for 60 countries over the period

  16. Factors leading to inflation targeting : The impact of adoption

    NARCIS (Netherlands)

    Samarina, Anna; Sturm, Jan-Egbert

    2013-01-01

    This paper examines how the analysis of inflation targeting (IT) adoption is affected by allowing for a structural change after adoption, using panel probit models for 60 countries over the period 1985-2008. Our findings suggest that there is a structural change after IT adoption. Including the

  17. Interactions of 160 GeV/Nucleon $^{207}$Pb Nuclei in Emulsion Chambers with Copper and Lead Targets

    CERN Multimedia

    2002-01-01

    % EMU13 \\\\ \\\\ Nuclear emulsions will be used as targets and trackers to investigate the interactions of $^{207}$Pb nuclei in emulsion, copper and lead targets; specifically (i) the pseudorapidity distributions of charged particles including analysis of particle fluctuations in pseudorapidity and azimuthal angle distributions, (ii) the transverse momentum distribution of $\\alpha$ fragments from the projectile nucleus. \\\\ \\\\Several emulsion chambers with different geometry and targets will be exposed to the $^{207}$Pb beam. Each chamber will be irradiated with the beam of low density $^{207}$Pb ions (several hundred per cm$^2$). Interactions with small impact parameter, characterized by high multiplicity and disruption of the projectile nucleus will be found with high efficiency. Measurements in the emulsion will include the number and emission angles of charged particles produced and the emission angles of $\\alpha$ fragments from the projectile nucleus.

  18. Targeted deletion of kidney glucose-6 phosphatase leads to nephropathy

    NARCIS (Netherlands)

    Clar, Julie; Gri, Blandine; Calderaro, Julien; Birling, Marie-Christine; Herault, Yann; Smit, G. Peter A.; Mithieux, Gilles; Rajas, Fabienne

    2014-01-01

    Renal failure is a major complication that arises with aging in glycogen storage disease type 1a and type 1b patients. In the kidneys, glucose-6 phosphatase catalytic subunit (encoded by G6pc) deficiency leads to the accumulation of glycogen, an effect resulting in marked nephromegaly and

  19. Comparison on the production of radionuclides in 1.4 GeV proton irradiated LBE targets of different thickness

    CERN Document Server

    Maiti, Moumita; Mendonça, Tania M; Stora, Thierry; Lahiri, Susanta

    2014-01-01

    This is the first report on the inventory of radionuclides produced in 1.4 GeV proton induced reaction on Lead-Bismuth Eutectic (LBE) targets. LBE targets of 6 mm diameter and 1 to 8 mm lengths were irradiated with 1.4 GeV protons. The radionuclides ranging from Be-7 (53.12 days) to Po-207 (5.8 h) were identified in the samples with the help of time resolved gamma-ray spectroscopy. However, there is no signature of formation of At radioisotopes, which can be produced by the interaction of secondary particles, typical for thick targets.

  20. Thin-film preparation by back-surface irradiation pulsed laser deposition using metal powder targets

    Science.gov (United States)

    Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Yamauchi, Makiko; Suda, Yoshiaki

    2017-01-01

    Several kinds of functional thin films were deposited using a new thin-film preparation method named the back-surface irradiation pulsed laser deposition (BIPLD) method. In this BIPLD method, powder targets were used as the film source placed on a transparent target holder, and then a visible-wavelength pulsed laser was irradiated from the holder side to the substrate. Using this new method, titanium oxide and boron nitride thin films were deposited on the silicon substrate. Surface scanning electron microscopy (SEM) images suggest that all of the thin films were deposited on the substrate with some large droplets irrespective of the kind of target used. The deposition rate of the films prepared by using this method was calculated from film thickness and deposition time to be much lower than that of the films prepared by conventional PLD. X-ray diffraction (XRD) measurement results suggest that rutile and anatase TiO2 crystal peaks were formed for the films prepared using the TiO2 rutile powder target. Crystal peaks of hexagonal boron nitride were observed for the films prepared using the boron nitride powder target. The crystallinity of the prepared films was changed by annealing after deposition.

  1. Remotely Operated Equipment for Post Irradiation Examination of the SNS Target Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, Adam J [ORNL; Graves, Van B [ORNL; Dayton, Michael J [ORNL; Riemer, Bernie [ORNL

    2011-01-01

    The Spallation Neutron Source produces neutrons by accelerating protons into flowing mercury contained inside a stainless steel target vessel. During facility operation the target vessel is degraded by a combination of high-energy neutrons, the proton beam, and cavitation-induced corrosion. The degradation is primarily concentrated at the nose of the target vessel, where the proton beam passes through. Currently, the Spallation Neutron Source has replaced three target vessels and is operating the fourth. To minimize the operational costs of manufacturing and disposing of target vessels, efforts are underway to increase the operational lifetimes of the target vessels by conducting post irradiation examinations of spent vessels. This examination involves remotely removing multiple coupons from the nose of the target vessel using a single piece of equipment, called the Nose Sampling Cutter, installed inside the Spallation Neutron Source s hot cell. The Cutter produces circular coupons approximately 2 inches in diameter using a carbide-tipped hole saw. The nose of the target vessel consists of four layers of material, and the Nose Sampling Cutter is capable of cutting through the layers in a single stroke. This remote operation has been successfully completed twice. In addition to the Nose Sampling Cutter, a large reciprocation saw capable of removing a sizable section of the nose of the target vessel has been constructed and tested, but never implemented. To support this large reciprocation saw other equipment has also been designed. The details of the Nose Sampling Cutter, reciprocation saw, and associated equipment are discussed.

  2. Numerical study of the irradiation uniformity of a directly driven inertial confinement fusion target

    Science.gov (United States)

    Temporal, M.; Canaud, B.; Laffite, S.; Le Garrec, B. J.; Murakami, M.

    2010-11-01

    In the Inertial Confinement Fusion the uniformity of the irradiation still represents a crucial issue. In this context a spherical capsule directly driven by laser beams have been assessed numerically [1]. Two schemes characterized by 32 and 48 directions of irradiation [2] with associated a single laser beam or a bundle of laser beams [3] characterized by a super-Gaussian intensity profile are considered. Beam imperfections as power imbalance and pointing errors have been taken into account. It is found that the focal spot that minimizes the rms deviation depends on the beam imperfections [4]. The numerical calculations show that the uniformity of the irradiation evolves in time. The results calculated considering the illumination of a spherical target will be compared with those obtained when the irradiation is taken into account. [1] M. Temporal, B. Canaud. Eur. Phys. J. D 55 139 (2009). [2] M. Murakami, N. Sarukura, H. Azechi, M. Temporal, A.J. Schmitt, in press to Phys. Plasmas (July issue, 2010). [3] M. Temporal, B. Canaud, B. J. Le Garrec, Phys. Plasmas 17 022701 (2010). [4] M. Temporal, B. Canaud, S. Laffite, B.J. Le Garrec, M. Murakami. Phys. Plasmas 17 064504 (2010).

  3. Compaction and sintering of nickel powder used encapsulation of irradiation targets

    Energy Technology Data Exchange (ETDEWEB)

    Miyano, Rosana S.L.; Guimaraes, Raquel R.F.L.; Rossi, Jesualdo L., E-mail: rosatac@gmail.com, E-mail: raquel.lucchesi@icloud.com, E-mail: jelrossi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais; Wendhausen, Paulo A.P.; Evangelista, Leandro L., E-mail: paulo.wendhausen@ufsc.br, E-mail: leandro.materiais@gmail.com [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Laboratorio de Materiais

    2015-07-01

    The objective of this study was to develop an alternative way to produce targets for irradiation containing uranium, for the pair of {sup 99}Mo production {sup 99m}Tc radionuclide. These targets were obtained by powder metallurgy, the compact serving as means for encapsulation a uranium cylinder to be irradiated. The targets were compacted in an axial hydraulic press applying different pressures up to 800 MPa. The sintering temperature was 600 °C in hydrogen atmosphere and it was used two sintering cycles, one for 4 h and the for 4 h plus 8 h time. The nickel powder was of high purity, that in order to provide the sealing of the fissile content within the compacted. The bulk density of compacted was evaluated by the method geometric. The porosity was measured by mercury porosimetry technique. The microstructure was investigated by optical microscopy. The results obtained with sintering powders involving confirm the feasibility of achieving a casing for uranium targets. (author)

  4. Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

    Energy Technology Data Exchange (ETDEWEB)

    Constanzo, Julie; Paquette, Benoit; Charest, Gabriel [Center for Radiotherapy Research, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Québec J1H 5N4 (Canada); Masson-Côté, Laurence; Guillot, Mathieu, E-mail: mathieu.guillot@usherbrooke.ca [Department of Radiation Oncology, Centre Hospitalier Universitaire de Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada and Center for Radiotherapy Research, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Québec J1H 5N4 (Canada)

    2015-05-15

    Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brain were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.

  5. Reduced cost design of liquid lithium target for international fusion material irradiation facility (IFMIF)

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hiroo; Ida, Mizuho; Sugimoto, Masayoshi; Takeuchi, Hiroshi [Department of Fussion Engineering Research, Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Yutani, Toshiaki [Toshiba Corp., Tokyo (Japan)

    2001-01-01

    The International Fusion Materials Irradiation Facility (IFMIF) is being jointly planned to provide an accelerator-based D-Li neutron source to produce intense high energy neutrons (2 MW/m{sup 2}) up to 200 dpa and a sufficient irradiation volume (500 cm{sup 3}) for testing the candidate materials and components up to about a full lifetime of their anticipated use in ITER and DEMO. To realize such a condition, 40 MeV deuteron beam with a current of 250 mA is injected into high speed liquid lithium flow with a speed of 20 m/s. Following Conceptual Design Activity (1995-1998), a design study with focus on cost reduction without changing its original mission has been done in 1999. The following major changes to the CAD target design have been considered in the study and included in the new design: i) number of the Li target has been changed from 2 to 1, ii) spare of impurity traps of the Li loop was removed although the spare will be stored in a laboratory for quick exchange, iii) building volume was reduced via design changes in lithium loop length. This paper describes the reduced cost design of the lithium target system and recent status of Key Element Technology activities. (author)

  6. Shielding behavior of V{sub 2}O{sub 5} doped lead borate glasses towards gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ghoneim, N.A.; ElBatal, H.A. [Glass Research Department, National Research Center, Dokki, Cairo (Egypt); Abdelghany, A.M., E-mail: a.m_abdelghany@yahoo.com [Spectroscopy Department, National Research Center, Dokki, Cairo (Egypt); Ali, I.S. [High Institute for Optics Technology, Dokki, Cairo (Egypt)

    2011-06-16

    Highlights: > Base lead borate glass together with samples of the same composition doped with varying V{sub 2}O{sub 5} contents were prepared. > UV-visible and infrared spectroscopy were measured before and after successive gamma irradiation. > Glass samples are observed to absorb strongly in the UV. > Infrared absorption spectra indicate the presence of both triangular and tetrahedral borate groups besides the sharing of lead ions in network forming and network modifying sites. - Abstract: Undoped lead borate glass of the composition PbO 70%-B{sub 2}O{sub 3} 30% together with samples of the same composition and doped with varying V{sub 2}O{sub 5} contents were prepared. UV-visible absorption spectra were measured out in the range 200-1500 nm before and after successive gamma irradiation. Infrared absorption measurements within the range 4000-400 cm{sup -1} were carried out for the undoped and V{sub 2}O{sub 5} doped samples before gamma irradiation and after being irradiated with a dose of 6 Mrad. All the glass samples are observed to absorb strongly in the UV region due to the combined contributions of absorption due to trace iron impurities and that from the divalent lead Pb{sup 2+} ions. The V{sub 2}O{sub 5}-doped glasses reveal extra visible absorption bands which are attributed to the existence of V{sup 3+} ions in measurable content but not neglecting the other valence states of vanadium ions (V{sup 4+}, V{sup 5+}). Infrared absorption spectra indicate the presence of both triangular and tetrahedral borate groups besides the sharing of lead ions in network forming and network modifying sites.

  7. Mono-energetic ions emission by nanosecond laser solid target irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Muoio, A., E-mail: Annamaria.Muoio@lns.infn.it [Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Messina, Viale F.S. D’Alcontres 31, 98166 Messina (Italy); Tudisco, S. [Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Altana, C. [Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via S. Sofia 64, 95123 Catania (Italy); Lanzalone, G. [Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Università degli Studi di Enna “Kore”, Via delle Olimpiadi, 94100 Enna (Italy); Mascali, D.; Cirrone, G.A.P.; Schillaci, F. [Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud, Via S. Sofia 62, 95123 Catania (Italy); Trifirò, A. [Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Messina, Viale F.S. D’Alcontres 31, 98166 Messina (Italy); Sezione INFN, Catania (Italy)

    2016-09-01

    An experimental campaign aiming to investigate the acceleration mechanisms through laser–matter interaction in nanosecond domain has been carried out at the LENS (Laser Energy for Nuclear Science) laboratory of INFN-LNS, Catania. Pure Al targets were irradiated by 6 ns laser pulses at different pumping energies, up to 2 J. Advanced diagnostics tools were used to characterize the plasma plume and ion production. We show the preliminary results of this experimental campaign, and especially the ones showing the production of multicharged ions having very narrow energy spreads.

  8. -Irradiation effect on the acoustical properties of zinc lead borate glasses

    Science.gov (United States)

    Sharma, G.; Singh, K.; Manupriya; Klare, H. S.; Rajendran, V.; Gayathri Devi, A. V.; Narang, S. B.

    2005-11-01

    The effect of -irradiation on the acoustical properties of xZnO.2xPbO.(1-3x)B2O3 glasses has been studied. Ultrasonic velocity and attenuation measurements have been made before and after -irradiation at room temperature in the frequency range 2.25-10 MHz. From the measured density and ultrasonic velocity data, the elastic moduli, Poisson's ratio and other parameters have been obtained. Changes in the acoustical properties are explained in terms of radiation-induced structural defects and the influence of PbO/ZnO in the glass network structure.

  9. Nanostructured targets irradiation by ns-laser for nuclear astrophysics applications: first results

    Science.gov (United States)

    Muoio, A.; Altana, C.; Frassetto, M.; Lanzalone, G.; Malferrari, L.; Mascali, D.; Odorici, F.; Tudisco, S.

    2017-03-01

    The studies discussed in this work are related to a scientific program that aims to reproduce astrophysical-plasmas in laboratory in order to better understand the nuclear processes involved in the stellar burning. An experimental campaign aiming to investigate the effects of innovative nanostructured targets based on Ni, Fe and Co nanowires on laser energy absorption in the ns time domain has been carried out at the LENS (Laser Energy for Nuclear Science) laboratory of INFN-LNS, Catania. Nanowires structures are tuned to increase the light absorption in the visible and infrared range due possibly to plasmonic excitation driven by the incoming photons. Different diagnostics techniques permit to monitor the plasma and to determine its reproducibility. Targets were then irradiated by Nd:YAG 2J, 6 ns infrared laser (λ = 1064 nm) at different pumping energies. Some preliminary results will be illustrated.

  10. Generation of soft x-ray radiation by laser irradiation of a gas puff xenon target

    Energy Technology Data Exchange (ETDEWEB)

    Fiedorowicz, H.; Bartnik, A.; Szczurek, M. [Military Univ. of Technology, Warsaw (Poland). Inst. of Optoelectronics] [and others

    1995-12-31

    Plasmas produced from laser-irradiated gas puff xenon targets, created by pulsed injection of xenon with high-pressure solenoid valve, offer the possibility of realizing a debrisless x-ray point source for the x-ray lithography applications. In this paper the authors present results of the experimental investigations on the x-ray generation from a gas puff xenon target irradiated with nanosecond high-power laser pulses produced using two different laser facilities: a Nd:glass laser operating at 1.06 {micro}m, which generated 10--15 J pulses in 1 ns FWHM, and Nd:glass slab laser, producing pulses of 10 ns duration with energy reaching 12 J for a 0.53 {micro}m wavelength or 20 J for 1.05 {micro}m. To study the x-ray emission different x-ray diagnostic methods have been used. X-ray spectra were registered using a flat CsAP crystal spectrograph with an x-ray film or a curved KAP crystal spectrograph with a convex curvature to an x-ray CCD readout detector. X-ray images have been taken using pinhole cameras with an x-ray film or a CCD array. X-ray yield was measured with the use of semiconductor detectors (silicon photodiodes or diamond photoconductors).

  11. Experiments and analysis of gold disk targets irradiated by smoothing beams of Xingguang II facilities with 350 nm wavelength

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-II) laser facilities with 350 nm wavelength, 0.6 ns pulse width and 20-80 Joules energies. Laser absorption, light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser absorption and scattered light were about 90% and 10%, respectively, under focusing irradiation, but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of focusing irradiation, the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity, X-ray conversion increased. This is highly advantageous to the inertial confinement fusion. However, X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irradiation was basically the same.

  12. Experiments and analysis of gold disk targets irradiated by smoothing beams of Xingguang II facilities with 350 nm wavelength

    Institute of Scientific and Technical Information of China (English)

    JIANG; ShaoEn

    2007-01-01

    Gold disk targets were irradiated using focusing and beam smoothing methods on Xingguang (XG-II) laser facilities with 350 nm wavelength, 0.6 ns pulse width and 20-80 Joules energies. Laser absorption, light scattering and X-ray conversion were experimentally investigated. The experimental results showed that laser absorption and scattered light were about 90% and 10%, respectively, under focusing irradiation, but the laser absorption increased 5%-10% and the scattered light about 1% under the condition of beam smoothing. Compared with the case of focusing irradiation, the laser absorption was effectively improved and the scattered light remarkably dropped under uniform irradiation; then due to the decrease in laser intensity, X-ray conversion increased. This is highly advantageous to the inertial confinement fusion. However, X-ray conversion mechanism basically did not change and X-ray conversion efficiency under beam smoothing and focusing irradiation was basically the same.……

  13. 90 deg.Neutron emission from high energy protons and lead ions on a thin lead target

    CERN Document Server

    Agosteo, S; Foglio-Para, A; Mitaroff, W A; Silari, Marco; Ulrici, L

    2002-01-01

    The neutron emission from a relatively thin lead target bombarded by beams of high energy protons/pions and lead ions was measured at CERN in one of the secondary beam lines of the Super Proton Synchrotron for radiation protection and shielding calculations. Measurements were performed with three different beams: sup 2 sup 0 sup 8 Pb sup 8 sup 2 sup + lead ions at 40 GeV/c per nucleon and 158 GeV/c per nucleon, and 40 GeV/c mixed protons/pions. The neutron yield and spectral fluence per incident ion on target were measured at 90 deg.with respect to beam direction. Monte-Carlo simulations with the FLUKA code were performed for the case of protons and pions and the results found in good agreement with the experimental data. A comparison between simulations and experiment for protons, pions and lead ions have shown that--for such high energy heavy ion beams--a reasonable estimate can be carried out by scaling the result of a Monte-Carlo calculation for protons by the projectile mass number to the power of 0.80-0...

  14. Chlorin e6 Conjugated Interleukin-6 Receptor Aptamers Selectively Kill Target Cells Upon Irradiation

    Directory of Open Access Journals (Sweden)

    Sven Kruspe

    2014-01-01

    Full Text Available Photodynamic therapy (PDT uses the therapeutic properties of light in combination with certain chemicals, called photosensitizers, to successfully treat brain, breast, prostate, and skin cancers. To improve PDT, current research focuses on the development of photosensitizers to specifically target cancer cells. In the past few years, aptamers have been developed to directly deliver cargo molecules into target cells. We conjugated the photosensitizer chlorin e6 (ce6 with a human interleukin-6 receptor (IL-6R binding RNA aptamer, AIR-3A yielding AIR-3A-ce6 for application in high efficient PDT. AIR-3A-ce6 was rapidly and specifically internalized by IL-6R presenting (IL-6R+ cells. Upon light irradiation, targeted cells were selectively killed, while free ce6 did not show any toxic effect. Cells lacking the IL-6R were also not affected by AIR-3A-ce6. With this approach, we improved the target specificity of ce6-mediated PDT. In the future, other tumor-specific aptamers might be used to selectively localize photosensitizers into cells of interest and improve the efficacy and specificity of PDT in cancer and other diseases.

  15. Enhanced electron-positron pair production by ultra intense laser irradiating a compound target

    Science.gov (United States)

    Liu, Jian-Xun; Ma, Yan-Yun; Yu, Tong-Pu; Zhao, Jun; Yang, Xiao-Hu; Gan, Long-Fei; Zhang, Guo-Bo; Zhao, Yuan; Zhang, Shi-Jie; Liu, Jin-Jin; Zhuo, Hong-Bin; Shao, Fu-Qiu; Kawata, Shigeo

    2016-12-01

    High-energy-density electron-positron pairs play an increasingly important role in many potential applications. Here, we propose a scheme for enhanced positron production by an ultra intense laser irradiating a gas-Al compound target via the multi-photon Breit-Wheeler (BW) process. The laser pulse first ionizes the gas and interacts with a near-critical-density plasma, forming an electron bubble behind the laser pulse. A great deal of electrons are trapped and accelerated in the bubble, while the laser front hole-bores the Al target and deforms its front surface. A part of the laser wave is thus reflected by the inner curved target surface and collides with the accelerated electron bunch. Finally, a large number of γ photons are emitted in the forward direction via the Compton back-scattering process and the BW process is initiated. Dense electron-positron pairs are produced with a maximum density of 6.02× {{10}27} m-3. Simulation results show that the positron generation is greatly enhanced in the compound target, where the positron yield is two orders of magnitude greater than that in only the solid slab case. The influences of the laser intensity, gas density and length on the positron beam quality are also discussed, which demonstrates the feasibility of the scheme in practice.

  16. {gamma}-irradiation effect on the acoustical properties of zinc lead borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, G.; Singh, K.; Manupriya; Klare, H.S. [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Rajendran, V.; Gayathri Devi, A.V. [Department of Physics, Mepco Schlenk Engineering College, Mepco Engineering College (P.O.) 626005, Virudhunagar, Tamil Nadu (India); Narang, S.B. [Department of Electronics and Technology, Guru Nanak Dev University, Amritsar 143005 (India)

    2005-11-01

    The effect of {gamma}-irradiation on the acoustical properties of xZnO.2xPbO.(1-3x)B{sub 2}O{sub 3} glasses has been studied. Ultrasonic velocity and attenuation measurements have been made before and after {gamma}-irradiation at room temperature in the frequency range 2.25-10 MHz. From the measured density and ultrasonic velocity data, the elastic moduli, Poisson's ratio and other parameters have been obtained. Changes in the acoustical properties are explained in terms of radiation-induced structural defects and the influence of PbO/ZnO in the glass network structure. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Development of a PVD-based manufacturing process of monolithic LEU irradiation targets for {sup 99}Mo production

    Energy Technology Data Exchange (ETDEWEB)

    Hollmer, Tobias

    2015-08-03

    {sup 99}Mo is the most important radioisotope in nuclear medicine. It is produced by fission of uranium in irradiation targets. The usage of cylindrical monolithic targets can ensure a safe supply of {sup 99}Mo and at the same reduce the amount of highly radioactive waste generated during production. To manufacture these targets, a novel PVD-based technique was developed. Both the feasibility and the high efficiency of this process were demonstrated in a prototype apparatus.

  18. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady

  19. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady

  20. Non-targeted effects of photon and particle irradiation and the interaction with the immune system

    Directory of Open Access Journals (Sweden)

    Thomas Ernst Schmid

    2012-07-01

    Full Text Available Ionizing irradiation is an important clinical approach to treat solid tumors. Modern radiation technologies aim to selectively kill tumor cells and protect the surrounding normal tissue. The standard paradigm for radiation effects in cellular systems involves damage of the DNA including DNA double strand breaks, which are considered as most effective in destroying tumor cells. Due to their enhanced physical and radiobiological properties, high linear energy transfer (LET radiation qualities are of special interest in tumor therapy. Future radiation therapy strategies aim to utilize carbon ions to effectively treat highly aggressive tumors. More recently, evidence is emerging for non-DNA targeted effects of radiation, including mutations, chromosomal aberrations and changes in gene expression, which can occur in cells that were not directly exposed to radiation. Radiation oncologists are only gradually beginning to appreciate the clinical relevance of radiation-induced bystander effects, genomic instability and abscopal effects. Since these effects are sensed by the immune system, a combination of immunotherapy and irradiation presents a new therapeutic opportunity in the future.

  1. Systems and methods for managing shared-path instrumentation and irradiation targets in a nuclear reactor

    Science.gov (United States)

    Heinold, Mark R.; Berger, John F.; Loper, Milton H.; Runkle, Gary A.

    2015-12-29

    Systems and methods permit discriminate access to nuclear reactors. Systems provide penetration pathways to irradiation target loading and offloading systems, instrumentation systems, and other external systems at desired times, while limiting such access during undesired times. Systems use selection mechanisms that can be strategically positioned for space sharing to connect only desired systems to a reactor. Selection mechanisms include distinct paths, forks, diverters, turntables, and other types of selectors. Management methods with such systems permits use of the nuclear reactor and penetration pathways between different systems and functions, simultaneously and at only distinct desired times. Existing TIP drives and other known instrumentation and plant systems are useable with access management systems and methods, which can be used in any nuclear plant with access restrictions.

  2. Proton radiography of magnetic field produced by ultra-intense laser irradiating capacity-coil target

    CERN Document Server

    Wang, W W; Chen, J; Cai, H B; He, S K; Zhou, W M; Shan, L Q; Lu, F; Wu, Y C; Hong, W; Liu, D X; Bi, B; Zhang, F; Xue, F B; Li, B Y; Zhang, B; He, Y L; He, W; Jiao, J L; Dong, K G; Zhang, F Q; Deng, Z G; Zhang, Z M; Cui, B; Han, D; Zhou, K N; Wang, X D; Zhao, Z Q; Cao, L F; Zhang, B H; He, X T; Gu, Y Q

    2014-01-01

    Ultra-intense ultra-short laser is firstly used to irradiate the capacity-coil target to generate magnetic field. The spatial structure and temporal evolution of huge magnetic fields were studied with time-gated proton radiography method. A magnetic flux density of 40T was measured by comparing the proton deflection and particle track simulations. Although the laser pulse duration is only 30fs, the generated magnetic field can last for over 100 picoseconds. The energy conversion efficiency from laser to magnetic field can reach as high as ~20%. The results indicate that tens of tesla (T) magnetic field could be produced in many ultra intense laser facilities around the world, and higher magnetic field could be produced by picosecond lasers.

  3. Estrogen enhanced cell-cell signalling in breast cancer cells exposed to targeted irradiation

    Directory of Open Access Journals (Sweden)

    Held Kathryn D

    2008-06-01

    Full Text Available Abstract Background Radiation-induced bystander responses, where cells respond to their neighbours being irradiated are being extensively studied. Although evidence shows that bystander responses can be induced in many types of cells, it is not known whether there is a radiation-induced bystander effect in breast cancer cells, where the radiosensitivity may be dependent on the role of the cellular estrogen receptor (ER. This study investigated radiation-induced bystander responses in estrogen receptor-positive MCF-7 and estrogen receptor-negative MDA-MB-231 breast cancer cells. Methods The influence of estrogen and anti-estrogen treatments on the bystander response was determined by individually irradiating a fraction of cells within the population with a precise number of helium-3 using a charged particle microbeam. Damage was scored as chromosomal damage measured as micronucleus formation. Results A bystander response measured as increased yield of micronucleated cells was triggered in both MCF-7 and MDA-MB-231 cells. The contribution of the bystander response to total cell damage in MCF-7 cells was higher than that in MDA-MB-231 cells although the radiosensitivity of MDA-MB-231 was higher than MCF-7. Treatment of cells with 17β-estradiol (E2 increased the radiosensitivity and the bystander response in MCF-7 cells, and the effect was diminished by anti-estrogen tamoxifen (TAM. E2 also increased the level of intracellular reactive oxygen species (ROS in MCF-7 cells in the absence of radiation. In contrast, E2 and TAM had no influence on the bystander response and ROS levels in MDA-MB-231 cells. Moreover, the treatment of MCF-7 cells with antioxidants eliminated both the E2-induced ROS increase and E2-enhanced bystander response triggered by the microbeam irradiation, which indicates that ROS are involved in the E2-enhanced bystander micronuclei formation after microbeam irradiation. Conclusion The observation of bystander responses in breast

  4. Temperature effect of irradiated target surface on distribution of nanoparticles formed by implantation

    CERN Document Server

    Stepanov, A L; Popok, V N

    2001-01-01

    The composition layers, containing the metal nanoparticles, synthesized thorough implantation of the Ag sup + ions with the energy of 60 keV and the dose of 3 x 10 sup 1 sup 6 ion/cm sup 2 into the sodium-calcium silicate glass by the ion current of 3 mu A/cm sup 2 and the sublayer temperature of 35 deg C are studied. The obtained implantation results are analyzed in dependence on the temperature effects, developing for the glass samples of various thickness. The data on the silver distribution, the metal nanoparticles formation and growth by depth are obtained from the optical reflection spectra. It is demonstrated that minor changes in the surface temperature of the irradiated glass sublayer lead to noticeable diversities in the regularities of the nanoparticles formation in the sample volume

  5. Characterization of lead-bismuth eutectic target material for accelerator driven transmuters

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Yousry E-mail: gohar@anl.gov

    2003-05-15

    Lead-bismuth eutectic (LBE) is under consideration as a target material with high-energy protons for generating neutrons to drive actinide and fission product transmuters. A characterization has been performed to study the performance of this target material as a function of the main variables and the design selections. The characterization includes the neutron yield, the spatial energy deposition, the neutron spectrum, the beam window performance, and the target buffer requirements. The characterization has also considered high-energy deuteron particles to study the impact on the target neutronic performance. The obtained results quantify the LBE target material performance with proton or deuteron particles as a function of the target variables and selections.

  6. A new approach to the long-term reconstruction of the solar irradiance leads to large historical solar forcing

    Science.gov (United States)

    Shapiro, A. I.; Schmutz, W.; Rozanov, E.; Schoell, M.; Haberreiter, M.; Shapiro, A. V.; Nyeki, S.

    2011-05-01

    Context. The variable Sun is the most likely candidate for the natural forcing of past climate changes on time scales of 50 to 1000 years. Evidence for this understanding is that the terrestrial climate correlates positively with the solar activity. During the past 10 000 years, the Sun has experienced the substantial variations in activity and there have been numerous attempts to reconstruct solar irradiance. While there is general agreement on how solar forcing varied during the last several hundred years - all reconstructions are proportional to the solar activity - there is scientific controversy on the magnitude of solar forcing. Aims: We present a reconstruction of the total and spectral solar irradiance covering 130 nm-10 μm from 1610 to the present with an annual resolution and for the Holocene with a 22-year resolution. Methods: We assume that the minimum state of the quiet Sun in time corresponds to the observed quietest area on the present Sun. Then we use available long-term proxies of the solar activity, which are 10Be isotope concentrations in ice cores and 22-year smoothed neutron monitor data, to interpolate between the present quiet Sun and the minimum state of the quiet Sun. This determines the long-term trend in the solar variability, which is then superposed with the 11-year activity cycle calculated from the sunspot number. The time-dependent solar spectral irradiance from about 7000 BC to the present is then derived using a state-of-the-art radiation code. Results: We derive a total and spectral solar irradiance that was substantially lower during the Maunder minimum than the one observed today. The difference is remarkably larger than other estimations published in the recent literature. The magnitude of the solar UV variability, which indirectly affects the climate, is also found to exceed previous estimates.We discuss in detail the assumptions that lead us to this conclusion. Appendix is only available in electronic form at http://www.aanda.org

  7. Lead

    Science.gov (United States)

    ... found? Who is at risk? What are the health effects of lead? Get educational material about lead Get certified as a Lead Abatement Worker, or other abatement discipline Lead in drinking water Lead air pollution Test your child Check and maintain your home ...

  8. Synthesis of specific nanoparticles for targeting tumor angiogenesis using electron-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Deshayes, Stephanie, E-mail: stephanie.deshayes@u-bordeaux2.f [Universite de Bordeaux, UMR CNRS 5084, CNAB, Chimie Bio-Organique, 33076 Bordeaux (France); Ecole Polytechnique, CEA, UMR CNRS 7642, Laboratoire des Solides Irradies, 91128 Palaiseau (France); Maurizot, Victor [Universite de Bordeaux, UMR CNRS 5084, CNAB, Chimie Bio-Organique, 33076 Bordeaux (France); Clochard, Marie-Claude; Berthelot, Thomas; Baudin, Cecile [Ecole Polytechnique, CEA, UMR CNRS 7642, Laboratoire des Solides Irradies, 91128 Palaiseau (France); Deleris, Gerard [Universite de Bordeaux, UMR CNRS 5084, CNAB, Chimie Bio-Organique, 33076 Bordeaux (France)

    2010-03-15

    Angiogenesis plays a critical role in both growth and metastasis of tumors. Vascular endothelial growth factor (VEGF) is an endogenous mediator of tumor angiogenesis. Blocking associations of the VEGF with its corresponding receptors (KDR) have become critical for anti-tumor therapy. A cyclo-peptide (CBO-P11), derived from VEGF, able to inhibit the interaction between the growth factor and its receptor, was synthesized in our laboratory to provide a target for angiogenesis. We have prepared biocompatible poly(vinylidene fluoride) (PVDF) nanoparticles in order to obtain long blood circulating systems. Electron-beam (EB) irradiation was used to activate the PVDF nanoparticles. From electron paramagnetic resonance (EPR) measurements, we studied the radical stability in order to optimize the radio-grafting of acrylic acid (AA). Further functionalization of PVDF-g-PAA nanoparticles with the cyclo-peptide via a spacer arm was also possible by performing coupling reactions. High resolution magic angle spinning nuclear magnetic resonance (HRMAS NMR) and MALDI mass spectrometry allowed us to follow each chemical step of this peptide immobilization. We designed a new nanodevice suggesting a great potential for targeting angiogenesis. 7727-21-1

  9. Enhanced X-ray emission from laser-produced gold plasma by double pulses irradiation of nano-porous targets

    Science.gov (United States)

    Fazeli, R.

    2017-02-01

    Enhancement of the soft X-ray emission including free-free, free-bound and bound-bound emissions from Au nano-porous targets irradiated by single and double laser pulses is studied through numerical simulations. Laser pulses of duration 2 ns are used in calculations considering different prepulse intensities and a fixed intensity of 1013 Wcm-2 for the main pulse. The effects of prepulse intensity and time separation between laser pulses are studied for targets of different porosities. Results show that the X-ray yield can be enhanced significantly by a nano-porous target having optimum initial density. Such enhancement can be more improved when double laser pulses with appropriate delay time and intensities irradiate nano-porous targets. It is shown that the enhancement will be reduced when the prepulse intensity is greater than a specific value.

  10. Determination of firing distance. Lead analysis on the target by atomic absorption spectroscopy (AAS).

    Science.gov (United States)

    Gagliano-Candela, Roberto; Colucci, Anna P; Napoli, Salvatore

    2008-03-01

    This paper reports a method for the determination of the firing distance. Atomic absorption spectroscopy (AAS) was used to determine the lead (Pb) pattern around bullet holes produced by shots on test targets from the gun. Test shots were made with a Colt 38 Special at 5, 10, 20, 25, 30, 35, 40, 45, 50, 60, 80, and 100 cm target distance. The target was created with sheets of Whatman no. 1 paper on a polystyrene support. The target was subdivided into three carefully cut out rings (1, 2, and 3; with external diameters of 1.4 cm; 5 cm; 10.2 cm, respectively). Each sample was analyzed with graphite furnace AAS. Lead values analysis performed for each ring yielded a linear relation between the firing distance (cm) and the logarithm of lead amounts (microg/cm(2)) in definite target areas (areas 2 + 3): [ln dPb(2+3) = a(0) + a(1)l]; where dPb(2+3) = lead microg/cm(2) of area 2 + 3; a(0) and a(1) are experimentally calculated; l = distance in cm.

  11. An automated flow system incorporating in-line acid dissolution of bismuth metal from a cyclotron irradiated target assembly for use in the isolation of astatine-211

    Energy Technology Data Exchange (ETDEWEB)

    O’Hara, Matthew J.; Krzysko, Anthony J.; Niver, Cynthia M.; Morrison, Samuel S.; Owsley, Stanley L.; Hamlin, Donald K.; Dorman, Eric F.; Scott Wilbur, D.

    2017-04-01

    Astatine-211 (211At) is a promising cyclotron-produced radionuclide being investigated for use in targeted alpha therapy of blood borne and metastatic cancers, as well as treatment of tumor remnants after surgical resections. The isolation of trace quantities of 211At, produced within several grams of a Bi metal cyclotron target, involves a complex, multi-step procedure: (1) Bi metal dissolution in strong HNO3, (2) distillation of the HNO3 to yield Bi salts containing 211At, (3) dissolution of the salts in strong HCl, (4) solvent extraction of 211At from bismuth salts with diisopropyl ether (DIPE), and (5) back-extraction of 211At from DIPE into NaOH, leading to a purified 211At product. Step (1) has been addressed first to begin the process of automating the onerous 211At isolation process. A computer-controlled Bi target dissolution system has been designed. The system performs in-line dissolution of Bi metal from the target assembly using an enclosed target dissolution block, routing the resulting solubilized 211At/Bi mixture to the subsequent process step. The primary parameters involved in Bi metal solubilization (HNO3 concentration and influent flow rate) were optimized prior to evaluation of the system performance on replicate cyclotron irradiated targets. The results indicate that the system performs reproducibly, having nearly quantitative release of 211At from irradiated targets, with cumulative 211At recoveries that follow a sigmoidal function. The predictable nature of the 211At release profile allows the user to tune the system to meet target processing requirements.

  12. Measurements of X-ray doses and spectra produced by picosecond laser-irradiated solid targets.

    Science.gov (United States)

    Yang, Bo; Qiu, Rui; Yu, Minghai; Jiao, Jinlong; Lu, Wei; Yan, Yonghong; Zhang, Bo; Zhang, Zhimeng; Zhou, Weimin; Li, Junli; Zhang, Hui

    2017-02-09

    Experiments have shown that high-intensity laser interaction with a solid target can generate significant X-ray doses. This study was conducted to determine the X-ray doses and spectra produced for picosecond laser-irradiated solid targets. The photon doses and X-ray spectra in the laser forward and side directions were measured using an XG III ps 300 TW laser system. For laser intensities of 7×10(18)-4×10(19)W/cm(2), the maximum photon dose was 16.8 mSv at 50cm with a laser energy of ~153J on a 1-mm Ta target. The photon dose in the forward direction increased more significantly with increasing laser intensity than that in the side direction. For photon energies >300keV, the X-ray spectrum can be fit with an effective temperature distribution of the exponential form, dN/dE = k× exp(-E/Tx). The X-ray temperature Tx increased with the laser intensity in the forward direction with values of 0.46-0.75MeV. Tx was less strongly correlated with the laser intensity in the side direction with values of 0.29-0.32MeV. The escaping electron spectrum was also measured. The measured electron temperature was correlated with the electron temperature predicted by the ponderomotive law. The observations in this experiment were also investigated numerically. A good agreement was observed between the experimental and simulation results.

  13. Results of the six-and-a-half day electron-accelerator irradiation of enriched Mo-100 targets for the production of Mo-99

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Jonah, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, V. [Argonne National Lab. (ANL), Argonne, IL (United States); Tkac, P. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Virgo, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, G. F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-10-01

    A six-and-a-half day irradiation of enriched Mo-100 target disks was performed by Argonne’s electron linac. This report describes the irradiation conditions and the means used to process the targets for shipment to NorthStar Medical Isotopes, LLC, for feed to their RadioGenixTM technetium generator.

  14. Analyses of the plasma generated by laser irradiation on sputtered target for determination of the thickness used for plasma generation

    Energy Technology Data Exchange (ETDEWEB)

    Kumaki, Masafumi, E-mail: masafumi.kumaki@riken.jp [Cooperative Major in Nuclear Energy, Waseda University, Shinjuku, Tokyo (Japan); RIKEN, Wako, Saitama (Japan); Ikeda, Shunsuke; Sekine, Megumi; Munemoto, Naoya [RIKEN, Wako, Saitama (Japan); Department of Energy Sciences, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Fuwa, Yasuhiro [RIKEN, Wako, Saitama (Japan); Department of Physics and Astronomy, Kyoto University, Uji, Kyoto (Japan); Cinquegrani, David [American Nuclear Society, University of Michigan, Ann Arbor, Michigan 48109 (United States); Kanesue, Takeshi; Okamura, Masahiro [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Washio, Masakazu [Cooperative Major in Nuclear Energy, Waseda University, Shinjuku, Tokyo (Japan)

    2014-02-15

    In Brookhaven National Laboratory, laser ion source has been developed to provide heavy ion beams by using plasma generation with 1064 nm Nd:YAG laser irradiation onto solid targets. The laser energy is transferred to the target material and creates a crater on the surface. However, only the partial material can be turned into plasma state and the other portion is considered to be just vaporized. Since heat propagation in the target material requires more than typical laser irradiation period, which is typically several ns, only the certain depth of the layers may contribute to form the plasma. As a result, the depth is more than 500 nm because the base material Al ions were detected. On the other hand, the result of comparing each carbon thickness case suggests that the surface carbon layer is not contributed to generate plasma.

  15. Demonstration of a neonlike argon soft-x-ray laser with a picosecond-laser-irradiated gas puff target.

    Science.gov (United States)

    Fiedorowicz, H; Bartnik, A; Dunn, J; Smith, R F; Hunter, J; Nilsen, J; Osterheld, A L; Shlyaptsev, V N

    2001-09-15

    We demonstrate a neonlike argon-ion x-ray laser, using a short-pulse laser-irradiated gas puff target. The gas puff target was formed by pulsed injection of gas from a high-pressure solenoid valve through a nozzle in the form of a narrow slit and irradiated with a combination of long, 600-ps and short, 6-ps high-power laser pulses with a total of 10 J of energy in a traveling-wave excitation scheme. Lasing was observed on the 3p (1)S(0)?3s (1)P(1) transition at 46.9 nm and the 3d (1)P(1)?3p (1)P(1) transition at 45.1 nm. A gain of 11 cm(-1) was measured on these transitions for targets up to 0.9 cm long.

  16. Performance of target irradiation in a high-power laser with a continuous phase plate and spectral dispersion.

    Science.gov (United States)

    Jiang, Xiujuan; Li, Jinghui; Wu, Rong; Zhu, Zhengtao; Zhou, Shenlei; Lin, Zunqi

    2013-11-01

    We report on the performance of target irradiation at the SG-II high-power laser facility with a continuous phase plate (CPP) and the technique of smoothing by spectral dispersion (SSD). Simulative and experimental results are presented, where the irradiation uniformity and energy concentration of the target spots are analyzed. The results show that the designed CPP can focus the spot energy into the desired region and shape a profile with steep edge and flat top, but the actual performance of the fabricated CPP needs some improvements. It is also proved that the CPP is insensitive to the long-scale wavefront distortion in the incident beam. The one-dimensional SSD configuration evidently works in smoothing the fine-scale intensity modulation inside the target spot.

  17. Molecular desorption of stainless steel vacuum chambers irradiated with 42 MeV/u lead ions

    CERN Document Server

    Mahner, E; Laurent, Jean Michel; Madsen, N

    2003-01-01

    In preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2 MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow discharges, nonevaporable getter coating) are reported in terms of the molecular desorption yields for H/sub 2 /, CH/sub 4/, CO, Ar, and CO/sub 2/. (16 refs).

  18. A mechanistic study of gold nanoparticle radiosensitisation using targeted microbeam irradiation

    Science.gov (United States)

    Ghita, Mihaela; McMahon, Stephen J.; Taggart, Laura E.; Butterworth, Karl T.; Schettino, Giuseppe; Prise, Kevin M.

    2017-01-01

    Gold nanoparticles (GNPs) have been demonstrated as effective radiosensitizing agents in a range of preclinical models using broad field sources of various energies. This study aimed to distinguish between these mechanisms by applying subcellular targeting using a soft X-ray microbeam in combination with GNPs. DNA damage and repair kinetics were determined following nuclear and cytoplasmic irradiation using a soft X-ray (carbon K-shell, 278 eV) microbeam in MDA-MB-231 breast cancer and AG01522 fibroblast cells with and without GNPs. To investigate the mechanism of the GNP induced radiosensitization, GNP-induced mitochondrial depolarisation was quantified by TMRE staining, and levels of DNA damage were compared in cells with depolarised and functional mitochondria. Differential effects were observed following radiation exposure between the two cell lines. These findings were validated 24 hours after removal of GNPs by flow cytometry analysis of mitochondrial depolarisation. This study provides further evidence that GNP radiosensitisation is mediated by mitochondrial function and it is the first report applying a soft X-ray microbeam to study the radiobiological effects of GNPs to enable the separation of physical and biological effects. PMID:28300190

  19. SU-D-304-02: Magnetically Focused Proton Irradiation of Small Field Targets

    Energy Technology Data Exchange (ETDEWEB)

    McAuley, GA; Slater, JM [Loma Linda University, Loma Linda, CA (United States); Slater, JD; Wroe, AJ [Loma Linda University Medical Center, Loma Linda, CA (United States)

    2015-06-15

    Purpose: To investigate the use of magnetic focusing for small field proton irradiations. It is hypothesized that magnetic focusing will provide significant dose distribution benefits over standard collimated beams for fields less than 10 mm diameter. Methods: Magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into hollow cylinders were designed and manufactured. Two focusing magnets were placed on a positioning track on our Gantry 1 treatment table. Proton beams with energies of 127 and 157 MeV, 15 and 30 mm modulation, and 8 mm initial diameters were delivered to a water tank using single-stage scattering. Depth dose distributions were measured using a PTW PR60020 diode detector and transverse profiles were measured with Gafchromic EBT3 film. Monte Carlo simulations were also performed - both for comparison with experimental data and to further explore the potential of magnetic focusing in silica. For example, beam spot areas (based on the 90% dose contour) were matched at Bragg depth between simulated 100 MeV collimated beams and simulated beams focused by two 400 T/m gradient magnets. Results: Preliminary experimental results show 23% higher peak to entrance dose ratios and flatter spread out Bragg peak plateaus for 8 mm focused beams compared with uncollimated beams. Monte Carlo simulations showed 21% larger peak to entrance ratios and a ∼9 fold more efficient dose to target delivery compared to spot-sized matched collimated beams. Our latest results will be presented. Conclusion: Our results suggest that rare earth focusing magnet assemblies could reduce skin dose and beam number while delivering dose to nominally spherical radiosurgery targets over a much shorter time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however expanded treatment sites can be also envisaged.

  20. Spallation yield of neutrons produced in thick lead target bombarded with 250 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Ma, F., E-mail: mf@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhanga, X.Y.; Ju, Y.Q.; Zhang, H.B.; Ge, H.L.; Wang, J.G. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, B. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Y.Y.; Xu, X.W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Luo, P.; Yang, L.; Zhang, Y.B.; Li, J.Y.; Xu, J.K. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liang, T.J. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S.L. [University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Y.W.; Gu, L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2015-01-01

    The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally. The neutron production was measured with the water-bath gold method. The thermal neutron distributions in the water were determined according to the measured activities of Au foils. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data. It was found out that the Au foils with cadmium cover significantly changed the spacial distribution of the thermal neutron field. The corrected neutron yield was deduced to be 2.23±0.19 n/proton by considering the influence of the Cd cover on the thermal neutron flux.

  1. Spallation yield of neutrons produced in thick lead target bombarded with 250 MeV protons

    Science.gov (United States)

    Chen, L.; Ma, F.; Zhanga, X. Y.; Ju, Y. Q.; Zhang, H. B.; Ge, H. L.; Wang, J. G.; Zhou, B.; Li, Y. Y.; Xu, X. W.; Luo, P.; Yang, L.; Zhang, Y. B.; Li, J. Y.; Xu, J. K.; Liang, T. J.; Wang, S. L.; Yang, Y. W.; Gu, L.

    2015-01-01

    The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally. The neutron production was measured with the water-bath gold method. The thermal neutron distributions in the water were determined according to the measured activities of Au foils. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data. It was found out that the Au foils with cadmium cover significantly changed the spacial distribution of the thermal neutron field. The corrected neutron yield was deduced to be 2.23 ± 0.19 n/proton by considering the influence of the Cd cover on the thermal neutron flux.

  2. First results of the irradiation program of inert matrices, targets and fuels for minor actinides transmutation in fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bonnerot, Jean-Marc; Ferroud-Plattet, Marie-Pierre; Lamontagne, Jerome [CEA Cadarache, Nuclear Energy Direction, Saint-Paul les Durance Cedex, 13108 (France); Warin, Dominique [CEA Valrho, Nuclear Energy Direction, DRCP, Bagnols-sur-Ceze Cedex, 30207 (France); Gosmain, Lionel [CEA Saclay, Nuclear Energy Direction, DMN, Gif sur Yvette, 91190 (France)

    2008-07-01

    A comprehensive irradiation program was started in France in 1992 to demonstrate the technical feasibility of the transmutation of minor actinides in current and future nuclear reactors, by means of inert support targets or dedicated fuels. The first step of the program (MATINA program) consisted in the irradiation of various inert materials intended as support matrix for transmutation targets, in the fast reactor Phenix, to select the best candidates. These inert materials included as well oxide and nitride ceramics - MgO, MgAl{sub 2}O{sub 4}, Al{sub 2}O{sub 3}, Y{sub 3}Al{sub 5}O{sub 12} and TiN - as refractory metals - W, Nb, Cr and V- and were irradiated under fast neutron flux at temperatures ranged between 650 and 1040 deg. C. The results show that in comparison to MgO, MgAl{sub 2}O{sub 4} and Al{sub 2}O{sub 3} inert matrices irradiated alone, the composite pellets containing UO{sub 2} particles, showed very different behaviors under irradiation. The swelling of MgO pellets is enhanced in the presence of fissile material whereas it is lowered for the Al{sub 2}O{sub 3}-UO{sub 2} pellets. MgAl{sub 2}O{sub 4}-UO{sub 2} pellets remained stable. The second step of the program aimed at testing the behavior of inert support targets containing americium. A new experiment ECRIX H involving composite pellets with an MgO matrix and AmO{sub 2-x} particles was performed in Phenix and completed in 2006. A rather low elongation of the pellet stack was observed and no significant diameter deformation of cladding was detected after irradiation. The analysis of the filling gas of the pin after puncturing, revealed that respectively 28% and 5% of the He and Xe+Kr created under irradiation were released in the expanding volume of the pin. ECRIX H, which is the first experiment on Am base target in Phenix, will undoubtedly represent a very important step in the general design approach about inert matrix support targets once the complete results should be available by the end of

  3. Facile synthesis of lead iodide nanostructures by microwave irradiation technique and their structural, morphological, photoluminescence and dielectric studies

    Science.gov (United States)

    Shkir, Mohd.; Yahia, I. S.; AlFaify, S.; Abutalib, M. M.; Muhammad, Shabbir

    2016-04-01

    Lead iodide (PbI2) nanostructures have been synthesized by co-precipitation, hydrothermal and rapidly by microwave irradiation techniques. SEM analysis indicated the formation of well aligned nanocrystals and nanorods of average diameter between 100 nm and 400 nm. The powder X-ray diffraction and FT-Raman spectroscopic analysis confirms the formation of a 2H-PbI2 polytypic predominantly. These studies also show that there is no extra phase due to impurity in the synthesized nanostructures. The optical energy band gap of nanostructures prepared by co-precipitation, hydrothermal and microwave irradiation techniques were found to be 2.283, 2.493, 2.542 eV and 2.331. 2.350, 2.375 eV calculated from UV-Vis absorption and diffuse reflectance data, respectively, which shows a clear blue shift in the wavelength due to confinement effect. Photoluminescence spectrum was recorded at different excitation wavelengths and shows clear blue shift in the emission peak which is due to the recombination of free excitons with band to band type transition and also may be due to confinement effect. Further the dielectric studies have been performed and a good enhancement in the dielectric constant has been observed due to small size of the fabricated nanostructures in comparison to bulk material.

  4. Self-overcoming of the boiling condition by pressure increment in a water target irradiated by proton beam

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Bong Hwan, E-mail: burnn@kirams.re.kr [Korea Institute of Radiological and Medical Sciences (KIRMAS), 75 Nowon-Gil, Nowon-Gu, Seoul 139-706 (Korea, Republic of); Kang, Joonsun; Jung, In Su; Ram, Han Ga; Park, Yeun Soo [Korea Institute of Radiological and Medical Sciences (KIRMAS), 75 Nowon-Gil, Nowon-Gu, Seoul 139-706 (Korea, Republic of); Cho, Hyung Hee [Department of Mechanical Engineering, Yonsei University, 134 Sinchon-Dong, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of)

    2013-11-11

    An experiment was conducted to examine and visualize the boiling phenomena inside a water target by irradiating it with a proton beam from MC-50 cyclotron. The boiling phenomena were recorded with a CMOS camera. While an increase of the fraction of the water vapor volume is generally considered to be normal when water is boiled by a proton beam, our experiment showed the opposite result. The volume expansion of the liquid water exceeded the compressibility of the initial air volume. A grid structure in front of the entrance window foil held the target volume constant. Therefore, the phenomena inside the target underwent an isochoric process, and the pressure inside the target was increased rapidly beyond the pressure at the boiling point. Consequently, there was no more bulk boiling in the Bragg-peak region in the target water. Our results show that the boiling of the water can be controlled by controlling the equilibrium pressure of the water target.

  5. Deuteron irradiation of W and WO3 for production of high specific activity (186)Re: Challenges associated with thick target preparation.

    Science.gov (United States)

    Balkin, Ethan R; Gagnon, Katherine; Strong, Kevin T; Smith, Bennett E; Dorman, Eric F; Emery, Robert C; Pauzauskie, Peter J; Fassbender, Michael E; Cutler, Cathy S; Ketring, Alan R; Jurisson, Silvia S; Wilbur, D Scott

    2016-09-01

    This investigation evaluated target fabrication and beam parameters for scale-up production of high specific activity (186)Re using deuteron irradiation of enriched (186)W via the (186)W(d,2n)(186)Re reaction. Thick W and WO3 targets were prepared, characterized and evaluated in deuteron irradiations. Full-thickness targets, as determined using SRIM, were prepared by uniaxially pressing powdered natural abundance W and WO3, or 96.86% enriched (186)W, into Al target supports. Alternatively, thick targets were prepared by pressing (186)W between two layers of graphite powder or by placing pre-sintered (1105°C, 12h) natural abundance WO3 pellets into an Al target support. Assessments of structural integrity were made on each target prepared. Prior to irradiation, material composition analyses were conducted using SEM, XRD, and Raman spectroscopy. Within a minimum of 24h post irradiation, gamma-ray spectroscopy was performed on all targets to assess production yields and radionuclidic byproducts. Problems were encountered with the structural integrity of some pressed W and WO3 pellets before and during irradiation, and target material characterization results could be correlated with the structural integrity of the pressed target pellets. Under the conditions studied, the findings suggest that all WO3 targets prepared and studied were unacceptable. By contrast, (186)W metal was found to be a viable target material for (186)Re production. Thick targets prepared with powdered (186)W pressed between layers of graphite provided a particularly robust target configuration.

  6. Oxygen-Content-Controllable Graphene Oxide from Electron-Beam-Irradiated Graphite: Synthesis, Characterization, and Removal of Aqueous Lead [Pb(II)].

    Science.gov (United States)

    Bai, Jing; Sun, Huimin; Yin, Xiaojie; Yin, Xianqiang; Wang, Shengsen; Creamer, Anne Elise; Xu, Lijun; Qin, Zhi; He, Feng; Gao, Bin

    2016-09-28

    A high-energy electron beam was applied to irradiate graphite for the preparation of graphene oxide (GO) with a controllable oxygen content. The obtained GO sheets were analyzed with various characterization tools. The results revealed that the oxygen-containing groups of GO increased with increasing irradiation dosages. Hence, oxygen-content-controllable synthesis of GO can be realized by changing the irradiation dosages. The GO sheets with different irradiation dosages were then used to adsorb aqueous Pb(II). The effects of contact time, pH, initial lead ion concentration, and ionic strength on Pb(II) sorption onto different GO sheets were examined. The sorption process was found to be very fast (completed within 20 min) at pH 5.0. Except ionic strength, which showed no/little effect on lead sorption, the other factors affected the sorption of aqueous Pb(II) onto GO. The maximum Pb(II) sorption capacities of GO increased with irradiation dosages, confirming that electron-beam irradiation was an effective way to increase the oxygen content of GO. These results suggested that irradiated GO with a controllable oxygen content is a promising nanomaterial for environmental cleanup, particularly for the treatment of cationic metal ions, such as Pb(II).

  7. Growth of ZnO nanostructures by femtosecond laser irradiation of polycrystalline targets

    Science.gov (United States)

    Escalante, G.; Ryu, Y. K.; de la Cruz, A. Ruíz; Puerto, D.; Solís, J.; Fernández, P.

    2015-11-01

    The formation of LIPSS upon irradiation with ultrashort laser pulses on the surface of polycrystalline ZnO samples and the potential use of irradiated areas as growth patterns for the production of highly ordered nanostructures upon redeposition have been studied. For this purpose, we have performed different sets of irradiation experiments including static irradiation experiments at low and high repetition rates, as well as scanned beam experiments at high repetition rate, this later in order to generate relatively large template regions for nanostructure growth by redeposition. In all cases, LIPSS formation has been achieved in the ZnO polycrystalline surface. Under appropriate irradiation conditions, the material is redeposited rendering a high density of nanostructures with high aspect ratios and good crystal quality. Given the special luminescent properties and applications of ZnO, particular attention has been paid to the luminescence properties after irradiation and after post-irradiation thermal treatments. The observed evolution has been correlated with evolution of point defects in the treated surfaces. Thermal treatments cause significant changes in both the topography and the cathodoluminescent emission, such as the development of laminar structures, the emergence of nucleation centers and the recovery of ultraviolet emission previously quenched as a consequence of irradiation. Interestingly, LIPSS remain after the luminescent recovery by thermal annealing, opening the possibility to control both luminescence properties and grain size while maintaining an ordered structure with a high effective surface area.

  8. Measurement of prompt gamma profiles in inhomogeneous targets with a knife-edge slit camera during proton irradiation

    Science.gov (United States)

    Priegnitz, M.; Helmbrecht, S.; Janssens, G.; Perali, I.; Smeets, J.; Vander Stappen, F.; Sterpin, E.; Fiedler, F.

    2015-06-01

    Proton and ion beam therapies become increasingly relevant in radiation therapy. To fully exploit the potential of this irradiation technique and to achieve maximum target volume conformality, the verification of particle ranges is highly desirable. Many research activities focus on the measurement of the spatial distributions of prompt gamma rays emitted during irradiation. A passively collimating knife-edge slit camera is a promising option to perform such measurements. In former publications, the feasibility of accurate detection of proton range shifts in homogeneous targets could be shown with such a camera. We present slit camera measurements of prompt gamma depth profiles in inhomogeneous targets. From real treatment plans and their underlying CTs, representative beam paths are selected and assembled as one-dimensional inhomogeneous targets built from tissue equivalent materials. These phantoms have been irradiated with monoenergetic proton pencil beams. The accuracy of range deviation estimation as well as the detectability of range shifts is investigated in different scenarios. In most cases, range deviations can be detected within less than 2 mm. In close vicinity to low-density regions, range detection is challenging. In particular, a minimum beam penetration depth of 7 mm beyond a cavity is required for reliable detection of a cavity filling with the present setup. Dedicated data post-processing methods may be capable of overcoming this limitation.

  9. Measurement of prompt gamma profiles in inhomogeneous targets with a knife-edge slit camera during proton irradiation.

    Science.gov (United States)

    Priegnitz, M; Helmbrecht, S; Janssens, G; Perali, I; Smeets, J; Vander Stappen, F; Sterpin, E; Fiedler, F

    2015-06-21

    Proton and ion beam therapies become increasingly relevant in radiation therapy. To fully exploit the potential of this irradiation technique and to achieve maximum target volume conformality, the verification of particle ranges is highly desirable. Many research activities focus on the measurement of the spatial distributions of prompt gamma rays emitted during irradiation. A passively collimating knife-edge slit camera is a promising option to perform such measurements. In former publications, the feasibility of accurate detection of proton range shifts in homogeneous targets could be shown with such a camera. We present slit camera measurements of prompt gamma depth profiles in inhomogeneous targets. From real treatment plans and their underlying CTs, representative beam paths are selected and assembled as one-dimensional inhomogeneous targets built from tissue equivalent materials. These phantoms have been irradiated with monoenergetic proton pencil beams. The accuracy of range deviation estimation as well as the detectability of range shifts is investigated in different scenarios. In most cases, range deviations can be detected within less than 2 mm. In close vicinity to low-density regions, range detection is challenging. In particular, a minimum beam penetration depth of 7 mm beyond a cavity is required for reliable detection of a cavity filling with the present setup. Dedicated data post-processing methods may be capable of overcoming this limitation.

  10. Momentum measurement by the Multiple Coulomb Scattering method in the OPERA lead emulsion target

    CERN Document Server

    Agafonova, N.; Altinok, O.; Anokhina, A.; Aoki, S.; Ariga, A.; Ariga, T.; Autiero, D.; Badertscher, A.; Bagulya, A.; Ben Dhahbi, A.; Bertolin, A.; Besnier, M.; Bozza, C.; Brugiere, T.; Brugnera, R.; Brunet, F.; Brunetti, G.; Buontempo, S.; Cazes, A.; Chaussard, L.; Chernyavskiy, M.; Chiarella, V.; Chukanov, A.; D'Ambrosio, N.; Dal Corso, F.; De Lellis, G.; del Amo Sanchez, P.; Declais, Y.; De Serio, M.; Di Capua, F.; Di Crescenzo, A.; Di Ferdinando, D.; Di Marco, N.; Dmitrievski, S.; Dracos, M.; Duchesneau, D.; Dusini, S.; Dzhatdoev, T.; Ebert, J.; Egorov, O.; Enikeev, R.; Ereditato, A.; Esposito, L.S.; Favier, J.; Ferber, T.; Fini, R.A.; Frekers, D.; Fukuda, T.; Garfagnini, A.; Giacomelli, G.; Giorgini, M.; Gollnitz, C.; Goldberg, J.; Golubkov, D.; Goncharova, L.; Gornushkin, Y.; Grella, G.; Grianti, F.; Guler, A.M.; Gustavino, C.; Hagner, C.; Hamada, K.; Hara, T.; Hierholzer, M.; Hollnagel, A.; Hoshino, K.; Ieva, M.; Ishida, H.; Jakovcic, K.; Jollet, C.; Juget, F.; Kamiscioglu, M.; Kazuyama, K.; Kim, S.H.; Kimura, M.; Kitagawa, N.; Klicek, B.; Knuesel, J.; Kodama, K.; Komatsu, M.; Kose, U.; Kreslo, I.; Kubota, H.; Lazzaro, C.; Lenkeit, J.; Lippi, I.; Ljubicic, A.; Longhin, A.; Loverre, P.; Lutter, G.; Malgin, A.; Mandrioli, G.; Manai, K.; Marteau, J.; Matsuo, T.; Matveev, V.; Mauri, N.; Medinaceli, E.; Meisel, F.; Meregaglia, A.; Migliozzi, P.; Mikado, S.; Miyamoto, S.; Monacelli, P.; Morishima, K.; Moser, U.; Muciaccia, M.T.; Naganawa, N.; Naka, T.; Nakamura, M.; Nakano, T.; Naumov, D.; Nikitina, V.; Niwa, K.; Nonoyama, Y.; Ogawa, S.; Okateva, N.; Olshevskiy, A.; Paniccia, M.; Paoloni, A.; Park, B.D.; Park, I.G.; Pastore, A.; Patrizii, L.; Pennacchio, E.; Pessard, H.; Pretzl, K.; Pilipenko, V.; Pistillo, C.; Polukhina, N.; Pozzato, M.; Pupilli, F.; Rescigno, R.; Roganova, T.; Rokujo, H.; Romano, G.; Rosa, G.; Rostovtseva, I.; Rubbia, A.; Russo, A.; Ryasny, V.; Ryazhskaya, O.; Sato, O.; Sato, Y.; Schembri, A.; Schmidt-Parzefall, W.; Schroeder, H.; Scotto Lavina, L.; Sheshukov, A.; Shibuya, H.; Shoziyoev, G.; Simone, S.; Sioli, M.; Sirignano, C.; Sirri, G.; Song, J.S.; Spinetti, M.; Stanco, L.; Starkov, N.; Stipcevic, M.; Strauss, T.; Strolin, P.; Takahashi, S.; Tenti, M.; Terranova, F.; Tezuka, I.; Tioukov, V.; Tolun, P.; Trabelsi, A.; Tran, T.; Tufanli, S.; Vilain, P.; Vladimirov, M.; Votano, L.; Vuilleumier, J.L.; Wilquet, G.; Wonsak, B.; Yakushev, V.; Yoon, C.S.; Yoshioka, T.; Yoshida, J.; Zaitsev, Y.; Zemskova, S.; Zghiche, A.; Zimmermann, R.

    2012-01-01

    A new method of momentum measurement of charged particles through Multiple Coulomb Scattering (MCS) in the OPERA lead emulsion target is presented. It is based on precise measurements of track angular deviations performed thanks to the very high resolution of nuclear emulsions. The algorithm has been tested with Monte Carlo (MC) pions. The results are found to describe within the expected uncertainties the data obtained from test beams. We also report a comparison of muon momenta evaluated through MCS in the OPERA lead emulsion target with those determined by the electronic detectors for neutrino charged current interaction events. The two independent measurements agree within the experimental uncertainties, and the results validate the algorithm developed for the emulsion detector of OPERA.

  11. Proton emission from thin hydrogenated targets irradiated by laser pulses at 1016 W/cm2a)

    Science.gov (United States)

    Torrisi, L.; Giuffrida, L.; Cutroneo, M.; Cirrone, P.; Picciotto, A.; Krasa, J.; Margarone, D.; Velyhan, A.; Laska, L.; Ullschmied, J.; Wolowski, J.; Badziak, J.; Rosinski, M.

    2012-02-01

    The iodine laser at PALS Laboratory in Prague, operating at 1315 nm fundamental harmonics and at 300 ps FWHM pulse length, is employed to irradiate thin hydrogenated targets placed in vacuum at intensities on the order of 1016 W/cm2. The laser-generated plasma is investigated in terms of proton and ion emission in the forward and backward directions. The time-of-flight technique, using ion collectors and semiconductor detectors, is used to measure the ion currents and the corresponding velocities and energies. Thomson parabola spectrometer is employed to separate the contribution of the ion emission from single laser shots. A particular attention is given to the proton production in terms of the maximum energy, emission yield, and angular distribution as a function of the laser energy, focal position, target thickness, and composition. Metallic and polymeric targets allow to generate protons with large energy range and different yield, depending on the laser, target composition, and target geometry properties.

  12. Large-angle scattering of multi-GeV muons on thin Lead targets

    CERN Document Server

    Longhin, A; Pupilli, F

    2015-01-01

    The probability of large-angle scattering for multi-GeV muons in thin ($t/X_0 \\sim 10^{-1}$) lead targets is studied. The new estimates presented here are based both on simulation programs (GEANT4 libraries) and theoretical calculations. In order to validate the results provided by simulation, a comparison is drawn with experimental data from the literature. This study is particularly relevant when applied to muons originating from $\

  13. Present and future contraception: does discovery of targets lead to new contraceptives?

    Science.gov (United States)

    Jensen, Jeffrey T

    2015-01-01

    Although many highly effective methods of reversible contraception are available, high rates of unintended pregnancy and abortion provide evidence that current methods do not meet the needs of all couples. In recent years, a number of highly specific targets have been identified in key pathways that regulate the development of male and female gametes. Support for development of novel approaches has moved from industry to governmental and foundation funders. Continued public funding will be needed to move promising leads into clinical trials.

  14. Enhancement of laser to X-ray conversion by counter-propagating laser beams irradiating thin gold targets

    Science.gov (United States)

    Zhao, Y.; Ge, Z. Y.; Ma, Y. Y.; Yang, X. H.; Xu, B. B.; Ramis, R.

    2017-03-01

    X-ray emission from laser irradiating solid target is an important X-ray source for various potential applications. Counter-propagating (C-P) laser beams configuration is proposed to enhance the laser to X-ray conversion efficiency (CE) from laser irradiating solid targets. One-dimensional radiation hydrodynamics simulations show that the total X-ray CE for the C-P lasers case is as high as 65%, which has a 13% improvement compared with the single laser case. The improvement is mainly caused by the enlarged radiation region, and the enhancement of X-ray emission is from soft X-ray. Detailed energy term distributions and influences of the foil thickness on the X-ray CEs for both cases are presented. It is found that the enhancement of radiation is attributed to lower thermal and kinetic energy of the C-P lasers scheme.

  15. Quantitative resistance can lead to evolutionary changes in traits not targeted by the resistance QTLs

    Science.gov (United States)

    Van den Berg, Femke; Lannou, Christian; Gilligan, Christopher A; van de Bosch, Frank

    2014-01-01

    This paper addresses the general concern in plant pathology that the introduction of quantitative resistance in the landscape can lead to increased pathogenicity. Hereto, we study the hypothetical case of a quantitative trait loci (QTL) acting on pathogen spore production per unit lesion area. To regain its original fitness, the pathogen can break the QTL, restoring its spore production capacity leading to an increased spore production per lesion. Or alternatively, it can increase its lesion size, also leading to an increased spore production per lesion. A data analysis shows that spore production per lesion (affected by the resistance QTL) and lesion size (not targeted by the QTL) are positively correlated traits, suggesting that a change in magnitude of a trait not targeted by the QTL (lesion size) might indirectly affect the targeted trait (spore production per lesion). Secondly, we model the effect of pathogen adaptation towards increased lesion size and analyse its consequences for spore production per lesion. The model calculations show that when the pathogen is unable to overcome the resistance associated QTL, it may compensate for its reduced fitness by indirect selection for increased pathogenicity on both the resistant and susceptible cultivar, but whereby the QTLs remain effective. PMID:24665339

  16. Quantitative resistance can lead to evolutionary changes in traits not targeted by the resistance QTLs.

    Science.gov (United States)

    Van den Berg, Femke; Lannou, Christian; Gilligan, Christopher A; van de Bosch, Frank

    2014-03-01

    This paper addresses the general concern in plant pathology that the introduction of quantitative resistance in the landscape can lead to increased pathogenicity. Hereto, we study the hypothetical case of a quantitative trait loci (QTL) acting on pathogen spore production per unit lesion area. To regain its original fitness, the pathogen can break the QTL, restoring its spore production capacity leading to an increased spore production per lesion. Or alternatively, it can increase its lesion size, also leading to an increased spore production per lesion. A data analysis shows that spore production per lesion (affected by the resistance QTL) and lesion size (not targeted by the QTL) are positively correlated traits, suggesting that a change in magnitude of a trait not targeted by the QTL (lesion size) might indirectly affect the targeted trait (spore production per lesion). Secondly, we model the effect of pathogen adaptation towards increased lesion size and analyse its consequences for spore production per lesion. The model calculations show that when the pathogen is unable to overcome the resistance associated QTL, it may compensate for its reduced fitness by indirect selection for increased pathogenicity on both the resistant and susceptible cultivar, but whereby the QTLs remain effective.

  17. Lead

    Science.gov (United States)

    ... Chapter 6 Chapter 7 Chapter 8 Chapter 9 Appendix I Appendix II Tables Figures State Programs Alabama Alaska Arizona ... Tool Kit Resources Healthy Homes and Lead Poisoning Prevention Training Center (HHLPPTC) Training Tracks File Formats Help: ...

  18. The scattering fields for a spherical target irradiated by a plane electromagnetic wave in an arbitrary direction

    Institute of Scientific and Technical Information of China (English)

    Li Ying-Le; Huang Ji-Ying

    2006-01-01

    The relation between corresponding trigonometric functions in two rotating coordinate systems is presented. The transformation formula for a vector in the two rotating spherical coordinate systems is obtained. The scattering fields for a spherical target irradiated by a plane electromagnetic wave in an arbitrary direction are derived. These fields in a particular case retrogress to those available in the literature. The obtained results have great potential in practical applications.

  19. Possible version of the compression degradation of the thermonuclear indirect-irradiation targets at the national ignition facility and a reason for the failure of ignition

    Science.gov (United States)

    Rozanov, V. B.; Vergunova, G. A.

    2017-01-01

    The main parameters of compression of a target and tendencies at change in the irradiation conditions are determined by analyzing the published results of experiments at the megajoule National Ignition Facility (NIF) on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry. A possible version of the "failure of ignition" of an indirect-irradiation target under the NIF conditions is attributed to radiation transfer. The application of onedimensional model to analyze the National Ignition Campaign (NIC) experiments allows identifying conditions corresponding to the future ignition regime and distinguishing them from conditions under which ignition does not occur.

  20. Possible version of the compression degradation of the thermonuclear indirect-irradiation targets at the national ignition facility and a reason for the failure of ignition

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, V. B., E-mail: rozanov@sci.lebedev.ru; Vergunova, G. A., E-mail: verg@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-01-15

    The main parameters of compression of a target and tendencies at change in the irradiation conditions are determined by analyzing the published results of experiments at the megajoule National Ignition Facility (NIF) on the compression of capsules in indirect-irradiation targets by means of the one-dimensional RADIAN program in the spherical geometry. A possible version of the “failure of ignition” of an indirect-irradiation target under the NIF conditions is attributed to radiation transfer. The application of onedimensional model to analyze the National Ignition Campaign (NIC) experiments allows identifying conditions corresponding to the future ignition regime and distinguishing them from conditions under which ignition does not occur.

  1. Parallel computation safety analysis irradiation targets fission product molybdenum in neutronic aspect using the successive over-relaxation algorithm

    Science.gov (United States)

    Susmikanti, Mike; Dewayatna, Winter; Sulistyo, Yos

    2014-09-01

    One of the research activities in support of commercial radioisotope production program is a safety research on target FPM (Fission Product Molybdenum) irradiation. FPM targets form a tube made of stainless steel which contains nuclear-grade high-enrichment uranium. The FPM irradiation tube is intended to obtain fission products. Fission materials such as Mo99 used widely the form of kits in the medical world. The neutronics problem is solved using first-order perturbation theory derived from the diffusion equation for four groups. In contrast, Mo isotopes have longer half-lives, about 3 days (66 hours), so the delivery of radioisotopes to consumer centers and storage is possible though still limited. The production of this isotope potentially gives significant economic value. The criticality and flux in multigroup diffusion model was calculated for various irradiation positions and uranium contents. This model involves complex computation, with large and sparse matrix system. Several parallel algorithms have been developed for the sparse and large matrix solution. In this paper, a successive over-relaxation (SOR) algorithm was implemented for the calculation of reactivity coefficients which can be done in parallel. Previous works performed reactivity calculations serially with Gauss-Seidel iteratives. The parallel method can be used to solve multigroup diffusion equation system and calculate the criticality and reactivity coefficients. In this research a computer code was developed to exploit parallel processing to perform reactivity calculations which were to be used in safety analysis. The parallel processing in the multicore computer system allows the calculation to be performed more quickly. This code was applied for the safety limits calculation of irradiated FPM targets containing highly enriched uranium. The results of calculations neutron show that for uranium contents of 1.7676 g and 6.1866 g (× 106 cm-1) in a tube, their delta reactivities are the still

  2. Ovarian cancer stem cells: Can targeted therapy lead to improved progression-free survival?

    Institute of Scientific and Technical Information of China (English)

    Christen; L; Walters; Haygood; Rebecca; C; Arend; J; Michael; Straughn; Donald; J; Buchsbaum

    2014-01-01

    Despite significant effort and research funds, epithelial ovarian cancer remains a very deadly disease. There are no effective screening methods that discover early stage disease; the majority of patients are diagnosed with advanced disease. Treatment modalities consist primarily of radical debulking surgery followed by taxane and platinum-based chemotherapy. Newer therapies including limited targeted agents and intraperitoneal delivery of chemotherapeutic drugs have improved disease-free intervals, but failed to yield longlasting cures in most patients. Chemotherapeutic resistance, particularly in the recurrent setting, plagues the disease. Targeting the pathways and mechanisms behind the development of chemoresistance in ovarian cancer could lead to significant improvement in patient outcomes. In many malignancies, including blood and other solid tumors, there is a subgroup of tumor cells, separate from the bulk population, called cancer stem cells(CSCs). These CSCs are thought to be the cause of metastasis, recurrence and resistance. However, todate, ovarian CSCs have been difficult to identify, isolate, and target. It is felt by many investigators that finding a putative ovarian CSC and a chemotherapeutic agent to target it could be the key to a cure for this deadly disease. This review will focus on recent advances in this arena and discuss some of the controversies surrounding the concept.

  3. First protein drug target's appraisal of lead-likeness descriptors to unfold the intervening chemical space.

    Science.gov (United States)

    Athar, Mohd; Lone, Mohsin Y; Jha, Prakash C

    2017-03-01

    Despite the advances in combinatorial chemistry, high throughput and virtual screening experiments, plethora of clinical studies disquiet due to lead and drug-likeness attritions. For mitigation, the knowledge of physicochemical properties are really useful for guiding and selection of compounds from libraries dictated by certain rule of thumbs. However, robust bio-technological and instrumental innovations have created exponential increase in novel compounds and databases which compelled rethinking of the evaluation procedures. Known descriptive molecular property filters proposed by Lipinski, Verber and Hann are not efficient enough to encompass long array of compounds. Moreover, these filters do not take into account the specificity of biological target. In this pursuit, we have tried to appraise eight molecular properties for two major classes of biological targets viz membrane proteins and ion channels binding ligands. These molecular properties were utilized to search for the specific attributes that can be identified as an intervening space for dictating the biological activity.

  4. Neutron production from 158 GeV/c per nucleon lead ions on thin copper and lead targets in the angular range 30-135 degree

    CERN Document Server

    Silari, Marco; Birattari, C; Foglio-Para, A; Gini, L; Mitaroff, Angela; Ulrici, L

    2002-01-01

    The neutron emission from 5, 10 and 20 mm thick lead and 10 and 20 mm thick copper targets bombarded by a lead ion beam with momentum of 158 GeV/c per nucleon were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident ion on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135 degree with respect to beam direction. Monte Carlo simulations with the FLUKA code were performed to establish a guess spectrum for the unfolding of the experimental data. The results have shown that, lacking Monte Carlo radiation transport codes dealing with ions with masses larger than 1 amu, a reasonable prediction can be carried out by scaling the result of a Monte Carlo calculation for protons by the projectile mass number to the power of 0.85-0.95 for a lead target and 0.88-1.03 for a copper target.

  5. Thorium silicate compound as a solid-state target for production of isomeric thorium-229 nuclei by electron beam irradiation

    Science.gov (United States)

    Borisyuk, P. V.; Vasilyev, O. S.; Lebedinskii, Y. Y.; Krasavin, A. V.; Tkalya, E. V.; Troyan, V. I.; Habibulina, R. F.; Chubunova, E. V.; Yakovlev, V. P.

    2016-09-01

    In this paper, we discuss an idea of the experiment for excitation of the isomeric transition in thorium-229 nuclei by irradiating with electron beam targets with necessary physical characteristics. The chemical composition and bandgap of ThSi10O22 were determined by X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. It was found that the energy gap is equal to 7.7 eV and does not change when the target is exposed to a medium energy electron beam for a long time. This indicates that the compound possesses high electron-beam resistance. A quantitative estimation of the output function of isomeric thorium-229 nuclei generated by interaction of nuclei with the secondary electron flow formed by irradiating the solid-state ThSi10O22-based target is given. The estimation shows that ThSi10O22 is a promising thorium-containing target for investigating excitation of the nuclear low-lying isomeric transition in the thorium-229 isotope using medium-energy electrons.

  6. Investigations of ultrafast charge dynamics in laser-irradiated targets by a self probing technique employing laser driven protons

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, H. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Kar, S., E-mail: s.kar@qub.ac.uk [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Cantono, G. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Department of Physics “E. Fermi”, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Research Unit Adriano Gozzini, via G. Moruzzi 1, Pisa 56124 (Italy); Nersisyan, G. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Brauckmann, S. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany); Doria, D.; Gwynne, D. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Macchi, A. [Department of Physics “E. Fermi”, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Research Unit Adriano Gozzini, via G. Moruzzi 1, Pisa 56124 (Italy); Naughton, K. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Willi, O. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany); Lewis, C.L.S.; Borghesi, M. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom)

    2016-09-01

    The divergent and broadband proton beams produced by the target normal sheath acceleration mechanism provide the unique opportunity to probe, in a point-projection imaging scheme, the dynamics of the transient electric and magnetic fields produced during laser-plasma interactions. Commonly such experimental setup entails two intense laser beams, where the interaction produced by one beam is probed with the protons produced by the second. We present here experimental studies of the ultra-fast charge dynamics along a wire connected to laser irradiated target carried out by employing a ‘self’ proton probing arrangement – i.e. by connecting the wire to the target generating the probe protons. The experimental data shows that an electromagnetic pulse carrying a significant amount of charge is launched along the wire, which travels as a unified pulse of 10s of ps duration with a velocity close to speed of light. The experimental capabilities and the analysis procedure of this specific type of proton probing technique are discussed. - Highlights: • Prompt charging of laser irradiated target generates ultra-short EM pulses. • Its ultrafast propagation along a wire was studied by self-proton probing technique. • Self-proton probing technique is the proton probing with one laser pulse. • Pulse temporal profile and speed along the wire were measured with high resolution.

  7. Thorium silicate compound as a solid-state target for production of isomeric thorium-229 nuclei by electron beam irradiation

    Directory of Open Access Journals (Sweden)

    P. V. Borisyuk

    2016-09-01

    Full Text Available In this paper, we discuss an idea of the experiment for excitation of the isomeric transition in thorium-229 nuclei by irradiating with electron beam targets with necessary physical characteristics. The chemical composition and bandgap of ThSi10O22 were determined by X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. It was found that the energy gap is equal to 7.7 eV and does not change when the target is exposed to a medium energy electron beam for a long time. This indicates that the compound possesses high electron-beam resistance. A quantitative estimation of the output function of isomeric thorium-229 nuclei generated by interaction of nuclei with the secondary electron flow formed by irradiating the solid-state ThSi10O22-based target is given. The estimation shows that ThSi10O22 is a promising thorium-containing target for investigating excitation of the nuclear low-lying isomeric transition in the thorium-229 isotope using medium-energy electrons.

  8. 40 CFR 745.226 - Certification of individuals and firms engaged in lead-based paint activities: target housing and...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Certification of individuals and firms engaged in lead-based paint activities: target housing and child-occupied facilities. 745.226 Section 745... § 745.226 Certification of individuals and firms engaged in lead-based paint activities: target housing...

  9. Cardiac resynchronization therapy: Dire need for targeted left ventricular lead placement and optimal device programming

    Institute of Scientific and Technical Information of China (English)

    Sokratis; Pastromas; Antonis; S; Manolis

    2014-01-01

    Cardiac resynchronization therapy(CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class Ⅱ, Ⅲ and ambulatory Ⅳ, reduced left ventricular(LV) function, and a widened QRS complex. CRT has been shown to improve symptoms, LV function, hospitalization rates, and survival. In order to maximize the benefit from CRT and reduce the number of non-responders, consideration should be given to target the optimal site for LV lead implantation away from myocardial scar and close to the latest LV site activation; and also to appropriately program the device paying particular attention to optimal atrioventricular and interventricular intervals. We herein review current data related to both optimal LV lead placement and device programming and their effects on CRT clinical outcomes.

  10. Interaction between x-irradiated plateau-phase bone marrow stromal cell lines and co-cultivated factor-dependent cell lines leading to leukemogenesis in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Naparstek, E.; Anklesaria, P.; FitzGerald, T.J.; Sakakeeny, M.A.; Greenberger, J.S.

    1987-03-01

    Plateau-phase mouse clonal bone marrow stromal cell lines D2XRII and C3H cl 11 produce decreasing levels of M-CSF (CSF-1), a specific macrophage progenitor cell humoral regulator, following X-irradiation in vitro. The decrease did not go below 40% of control levels, even after irradiation doses of 50,000 rad (500 Gy). In contrast, a distinct humoral regulator stimulating growth of GM-CSF/IL-3 factor-dependent (FD) hematopoietic progenitor cell lines was detected following radiation to doses above 2000 rad. This humoral factor was not detectable in conditioned medium from irradiated cells, weakly detected using factor-dependent target cell populations in agar overlay, and was prominently detected by liquid co-cultivation of factor-dependent cells with irradiated stromal cell cultures. Subclonal lines of FD cells, derived after co-cultivation revealed karyotypic abnormalities and induced myeloblastic tumors in syngeneic mice. Five-eight weeks co-cultivation was required for induction of factor independence and malignancy and was associated with dense cell to cell contact between FD cells and stromal cells demonstrated by light and electron microscopy. Increases in hematopoietic to stromal cell surface area, total number of adherent cells per flask, total non-adherent cell colonies per flask, and cumulative non-adherent cell production were observed after irradiation. The present data may prove very relevant to an understanding of the cell to cell interactions during X-irradiation-induced leukemia.

  11. OptForce: an optimization procedure for identifying all genetic manipulations leading to targeted overproductions.

    Directory of Open Access Journals (Sweden)

    Sridhar Ranganathan

    2010-04-01

    Full Text Available Computational procedures for predicting metabolic interventions leading to the overproduction of biochemicals in microbial strains are widely in use. However, these methods rely on surrogate biological objectives (e.g., maximize growth rate or minimize metabolic adjustments and do not make use of flux measurements often available for the wild-type strain. In this work, we introduce the OptForce procedure that identifies all possible engineering interventions by classifying reactions in the metabolic model depending upon whether their flux values must increase, decrease or become equal to zero to meet a pre-specified overproduction target. We hierarchically apply this classification rule for pairs, triples, quadruples, etc. of reactions. This leads to the identification of a sufficient and non-redundant set of fluxes that must change (i.e., MUST set to meet a pre-specified overproduction target. Starting with this set we subsequently extract a minimal set of fluxes that must actively be forced through genetic manipulations (i.e., FORCE set to ensure that all fluxes in the network are consistent with the overproduction objective. We demonstrate our OptForce framework for succinate production in Escherichia coli using the most recent in silico E. coli model, iAF1260. The method not only recapitulates existing engineering strategies but also reveals non-intuitive ones that boost succinate production by performing coordinated changes on pathways distant from the last steps of succinate synthesis.

  12. Development of a Charged Particle Microbeam for Targeted and Single Particle Subcellular Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C.

    2004-03-12

    The development of a charged particle microbeam for single particle, subcellular irradiations at the Massachusetts Institute of Technology Laboratory for Accelerator Beam Applications (MIT LABA) was initiated under this NEER aeard. The Microbeam apparatus makes use of a pre-existing electrostatic accelerator with a horizontal beam tube.

  13. Comparison of Irradiation and Wolbachia Based Approaches for Sterile-Male Strategies Targeting Aedes albopictus.

    Science.gov (United States)

    Atyame, Célestine M; Labbé, Pierrick; Lebon, Cyrille; Weill, Mylène; Moretti, Riccardo; Marini, Francesca; Gouagna, Louis Clément; Calvitti, Maurizio; Tortosa, Pablo

    2016-01-01

    The global expansion of Aedes albopictus together with the absence of vaccines for most of the arboviruses transmitted by this mosquito has stimulated the development of sterile-male strategies aiming at controlling disease transmission through the suppression of natural vector populations. In this context, two environmentally friendly control strategies, namely the Sterile Insect Technique (SIT) and the Wolbachia-based Incompatible Insect Technique (IIT) are currently being developed in several laboratories worldwide. So far however, there is a lack of comparative assessment of these strategies under the same controlled conditions. Here, we compared the mating capacities, i.e. insemination capacity, sterilization capacity and mating competitiveness of irradiated (35 Gy) and incompatible Ae. albopictus males at different ages and ratios under laboratory controlled conditions. Our data show that there was no significant difference in insemination capacity of irradiated and incompatible males, both male types showing lower capacities than untreated males at 1 day but recovering full capacity within 5 days following emergence. Regarding mating competitiveness trials, a global observed trend is that incompatible males tend to induce a lower hatching rate than irradiated males in cage controlled confrontations. More specifically, incompatible males were found more competitive than irradiated males in 5:1 ratio regardless of age, while irradiated males were only found more competitive than incompatible males in the 1:1 ratio at 10 days old. Overall, under the tested conditions, IIT seemed to be slightly more effective than SIT. However, considering that a single strategy will likely not be adapted to all environments, our data stimulates the need for comparative assessments of distinct strategies in up-scaled conditions in order to identify the most suitable and safe sterilizing technology to be implemented in a specific environmental setting and to identify the

  14. The study of neutron spectra in water bath from Pb target irradiated by 250MeV/u protons

    CERN Document Server

    Li, Yanyan; Ju, Yongqin; Ma, Fei; Zhang, Hongbin; Chen, Liang; Ge, Honglin; Luo, Peng; Zhou, Bin; Zhang, Yanbin; Li, Jianyang; Xu, Junkui; Wang, Songlin; Yang, Yongwei; Yang, Lei

    2014-01-01

    The spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with Cd cover. According to the measured activities of the foils, the neutron flux at different resonance energy were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code.

  15. Computational study of the generation of crystal defects in a bcc metal target irradiated by short laser pulses

    Science.gov (United States)

    Lin, Zhibin; Johnson, Robert A.; Zhigilei, Leonid V.

    2008-06-01

    The generation of crystal defects in a Cr target irradiated by a short, 200 fs, laser pulse is investigated in computer simulations performed with a computational model that combines the classical molecular dynamics method with a continuum description of the laser excitation of conduction band electrons, electron-phonon coupling, and electron heat conduction. Interatomic interactions are described by the embedded atom method (EAM) potential with a parametrization designed for Cr. The potential is tested by comparing the properties of the EAM Cr material with experimental data and predictions of density functional theory calculations. The simulations are performed at laser fluences close to the threshold for surface melting. Fast temperature variation and strong thermoelastic stresses produced by the laser pulse are causing surface melting and epitaxial resolidification, transient appearance of a high density of stacking faults along the {110} planes, and generation of a large number of point defects (vacancies and self-interstitials). The stacking faults appear as a result of internal shifts in the crystal undergoing a rapid uniaxial expansion in the direction normal to the irradiated surface. The stacking faults are unstable and disappear shortly after the laser-induced tensile stress wave leaves the surface region of the target. Thermally activated generation of vacancy-interstitial pairs during the initial temperature spike and quick escape of highly mobile self-interstitials to the melting front or the free surface of the target, along with the formation of vacancies at the solid-liquid interface during the fast resolidification process, result in a high density of vacancies, on the order of 10-3 per lattice site, created in the surface region of the target. The strong supersaturation of vacancies can be related to the incubation effect in multipulse laser ablation/damage and should play an important role in mixing/alloying of multicomponent or composite

  16. Target hazard quotient evaluation of cadmium and lead in fish from Caspian Sea.

    Science.gov (United States)

    Basim, Yalda; Khoshnood, Zahra

    2016-02-01

    Heavy metals are being increasingly released into the natural waters from geological and anthropogenic sources. The distributions of several heavy metals such as cadmium (Cd) and lead (Pb) were investigated in muscle and liver of three different fish species seasonally collected from Caspian Sea (autumn 2011-summer 2012). The concentrations of all metals were lower in flesh than those recorded in liver due to their physiological roles. The target hazard quotient (THQ) index for fish was calculated. Estimation of THQ calculations for the contaminated fish consumption was calculated to evaluate the effect of pollution on health. Total metal THQ values of Pb and Cd for adults were 0.05 and 0.04 in Anzali and Noshahr, respectively, and for children were 0.08 and 0.05 in Anzali and Noshahr, respectively.

  17. Fragile X and autism: Intertwined at the molecular level leading to targeted treatments.

    Science.gov (United States)

    Hagerman, Randi; Hoem, Gry; Hagerman, Paul

    2010-09-21

    Fragile X syndrome (FXS) is caused by an expanded CGG repeat (> 200 repeats) in the 5' untranslated portion of the fragile mental retardation 1 gene (FMR1), leading to deficiency or absence of the FMR1 protein (FMRP). FMRP is an RNA carrier protein that controls the translation of several other genes that regulate synaptic development and plasticity. Autism occurs in approximately 30% of FXS cases, and pervasive developmental disorder, not otherwise specified (PDD-NOS) occurs in an additional 30% of cases. Premutation repeat expansions (55 to 200 CGG repeats) may also give rise to autism spectrum disorders (ASD), including both autism and PDD-NOS, through a different molecular mechanism that involves a direct toxic effect of the expanded CGG repeat FMR1 mRNA. RNA toxicity can also lead to aging effects including tremor, ataxia and cognitive decline, termed fragile X-associated tremor ataxia syndrome (FXTAS), in premutation carriers in late life. In studies of mice bearing premutation expansions, there is evidence of early postnatal neuronal cell toxicity, presenting as reduced cell longevity, decreased dendritic arborization and altered synaptic morphology. There is also evidence of mitochondrial dysfunction in premutation carriers. Many of the problems with cellular dysregulation in both premutation and full mutation neurons also parallel the cellular abnormalities that have been documented in autism without fragile X mutations. Research regarding dysregulation of neurotransmitter systems in FXS, including the metabotropic glutamate receptor (mGluR)1/5 pathway and γ aminobutyric acid (GABA)A pathways, have led to new targeted treatments for FXS. Preliminary evidence suggests that these new targeted treatments will also be beneficial in non-fragile X forms of autism.

  18. Fragile X and autism: Intertwined at the molecular level leading to targeted treatments

    Directory of Open Access Journals (Sweden)

    Hagerman Randi

    2010-09-01

    Full Text Available Abstract Fragile X syndrome (FXS is caused by an expanded CGG repeat (> 200 repeats in the 5' untranslated portion of the fragile mental retardation 1 gene (FMR1, leading to deficiency or absence of the FMR1 protein (FMRP. FMRP is an RNA carrier protein that controls the translation of several other genes that regulate synaptic development and plasticity. Autism occurs in approximately 30% of FXS cases, and pervasive developmental disorder, not otherwise specified (PDD-NOS occurs in an additional 30% of cases. Premutation repeat expansions (55 to 200 CGG repeats may also give rise to autism spectrum disorders (ASD, including both autism and PDD-NOS, through a different molecular mechanism that involves a direct toxic effect of the expanded CGG repeat FMR1 mRNA. RNA toxicity can also lead to aging effects including tremor, ataxia and cognitive decline, termed fragile X-associated tremor ataxia syndrome (FXTAS, in premutation carriers in late life. In studies of mice bearing premutation expansions, there is evidence of early postnatal neuronal cell toxicity, presenting as reduced cell longevity, decreased dendritic arborization and altered synaptic morphology. There is also evidence of mitochondrial dysfunction in premutation carriers. Many of the problems with cellular dysregulation in both premutation and full mutation neurons also parallel the cellular abnormalities that have been documented in autism without fragile X mutations. Research regarding dysregulation of neurotransmitter systems in FXS, including the metabotropic glutamate receptor (mGluR1/5 pathway and γ aminobutyric acid (GABAA pathways, have led to new targeted treatments for FXS. Preliminary evidence suggests that these new targeted treatments will also be beneficial in non-fragile X forms of autism.

  19. Parallel computation safety analysis irradiation targets fission product molybdenum in neutronic aspect using the successive over-relaxation algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Susmikanti, Mike, E-mail: mike@batan.go.id [Center for Development of Nuclear Informatics, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia); Dewayatna, Winter, E-mail: winter@batan.go.id [Center for Nuclear Fuel Technology, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia); Sulistyo, Yos, E-mail: soj@batan.go.id [Center for Nuclear Equipment and Engineering, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia)

    2014-09-30

    One of the research activities in support of commercial radioisotope production program is a safety research on target FPM (Fission Product Molybdenum) irradiation. FPM targets form a tube made of stainless steel which contains nuclear-grade high-enrichment uranium. The FPM irradiation tube is intended to obtain fission products. Fission materials such as Mo{sup 99} used widely the form of kits in the medical world. The neutronics problem is solved using first-order perturbation theory derived from the diffusion equation for four groups. In contrast, Mo isotopes have longer half-lives, about 3 days (66 hours), so the delivery of radioisotopes to consumer centers and storage is possible though still limited. The production of this isotope potentially gives significant economic value. The criticality and flux in multigroup diffusion model was calculated for various irradiation positions and uranium contents. This model involves complex computation, with large and sparse matrix system. Several parallel algorithms have been developed for the sparse and large matrix solution. In this paper, a successive over-relaxation (SOR) algorithm was implemented for the calculation of reactivity coefficients which can be done in parallel. Previous works performed reactivity calculations serially with Gauss-Seidel iteratives. The parallel method can be used to solve multigroup diffusion equation system and calculate the criticality and reactivity coefficients. In this research a computer code was developed to exploit parallel processing to perform reactivity calculations which were to be used in safety analysis. The parallel processing in the multicore computer system allows the calculation to be performed more quickly. This code was applied for the safety limits calculation of irradiated FPM targets containing highly enriched uranium. The results of calculations neutron show that for uranium contents of 1.7676 g and 6.1866 g (× 10{sup 6} cm{sup −1}) in a tube, their delta

  20. Efficient and stable proton acceleration by irradiating a two-layer target with a linearly polarized laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. Y.; Yan, X. Q.; Chen, J. E.; He, X. T. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China) and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China); Ma, W. J.; Bin, J. H.; Schreiber, J.; Tajima, T.; Habs, D. [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Am Coulombwall 1, 85748 Garching (Germany) and Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany)

    2013-01-15

    We report an efficient and stable scheme to generate {approx}200 MeV proton bunch by irradiating a two-layer targets (near-critical density layer+solid density layer with heavy ions and protons) with a linearly polarized Gaussian pulse at intensity of 6.0 Multiplication-Sign 10{sup 20} W/cm{sup 2}. Due to self-focusing of laser and directly accelerated electrons in the near-critical density layer, the proton energy is enhanced by a factor of 3 compared to single-layer solid targets. The energy spread of proton is also remarkably reduced. Such scheme is attractive for applications relevant to tumor therapy.

  1. Optimal Dosing for Targeted Therapies in Oncology: Drug Development Cases Leading by Example.

    Science.gov (United States)

    Sachs, Jeffrey R; Mayawala, Kapil; Gadamsetty, Satvik; Kang, Soonmo Peter; de Alwis, Dinesh P

    2016-03-15

    One of the key objectives of oncology first-in-human trials has often been to establish the maximum tolerated dose (MTD). However, targeted therapies might not exhibit dose-limiting toxicities (DLT) at doses significantly higher than sufficiently active doses, and there is frequently a limited ability to objectively quantify adverse events. Thus, while MTD-based determination of recommended phase II dose may have yielded appropriate dosing for some cytotoxics, targeted therapeutics (including monoclonal antibodies and/or immunotherapies) sometimes need alternative or complementary strategies to help identify dose ranges for a randomized dose-ranging study. One complementary strategy is to define a biologically efficacious dose (BED) using an "effect marker." An effect marker could be a target engagement, pharmacodynamic, or disease progression marker (change in tumor size for solid tumors or bone marrow blast count for some hematologic tumors). Although the concept of BED has been discussed extensively, we review specific examples in which the approach influenced oncology clinical development. Data extracted from the literature and the examples support improving dose selection strategies to benefit patients, providers, and the biopharmaceutical industry. Although the examples illustrate key contributions of effect markers in dose selection, no one-size-fits-all approach to dosing can be justified. Higher-than-optimal dosing can increase toxicity in later trials (and in clinical use), which can have a negative impact on efficacy (via lower adherence or direct sequelae of toxicities). Proper dose selection in oncology should follow a multifactorial decision process leading to a randomized, dose-ranging study instead of a single phase II dose. ©2015 American Association for Cancer Research.

  2. Building a pipeline to discover and validate novel therapeutic targets and lead compounds for Alzheimer's disease.

    Science.gov (United States)

    Bennett, David A; Yu, Lei; De Jager, Philip L

    2014-04-15

    Cognitive decline, Alzheimer's disease (AD) and other causes are major public health problems worldwide. With changing demographics, the number of persons with dementia will increase rapidly. The treatment and prevention of AD and other dementias, therefore, is an urgent unmet need. There have been considerable advances in understanding the biology of many age-related disorders that cause dementia. Gains in understanding AD have led to the development of ante-mortem biomarkers of traditional neuropathology and the conduct of several phase III interventions in the amyloid-β cascade early in the disease process. Many other intervention strategies are in various stages of development. However, efforts to date have met with limited success. A recent National Institute on Aging Research Summit led to a number of requests for applications. One was to establish multi-disciplinary teams of investigators who use systems biology approaches and stem cell technology to identify a new generation of AD targets. We were recently awarded one of three such grants to build a pipeline that integrates epidemiology, systems biology, and stem cell technology to discover and validate novel therapeutic targets and lead compounds for AD treatment and prevention. Here we describe the two cohorts that provide the data and biospecimens being exploited for our pipeline and describe the available unique datasets. Second, we present evidence in support of a chronic disease model of AD that informs our choice of phenotypes as the target outcome. Third, we provide an overview of our approach. Finally, we present the details of our planned drug discovery pipeline. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Proton emission from thin hydrogenated targets irradiated by laser pulses at 10{sup 16} W/cm{sup 2}

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L. [INFN-LNS Via S. Sofia 44, 95123 Catania (Italy); Dip.to di Fisica, Universita di Messina, V.le F.S. D' Alcontres 31, 98166 S. Agata, Messina (Italy); Giuffrida, L.; Cirrone, P. [INFN-LNS Via S. Sofia 44, 95123 Catania (Italy); Cutroneo, M. [Dip.to di Fisica, Universita di Messina, V.le F.S. D' Alcontres 31, 98166 S. Agata, Messina (Italy); Picciotto, A. [Fondazione Bruno Kessler-IRST, Via Sommarive 18, 38050 Povo, Trento (Italy); Krasa, J.; Margarone, D.; Velyhan, A.; Laska, L.; Ullschmied, J. [Institute of Physics, ASCR, v.v.i., 182 21 Prague 8 (Czech Republic); Wolowski, J.; Badziak, J.; Rosinski, M. [Institute of Plasma Physics and Laser Microfusion, IPPLM, 23 Hery Str. 01-497 Warsaw (Poland)

    2012-02-15

    The iodine laser at PALS Laboratory in Prague, operating at 1315 nm fundamental harmonics and at 300 ps FWHM pulse length, is employed to irradiate thin hydrogenated targets placed in vacuum at intensities on the order of 10{sup 16} W/cm{sup 2}. The laser-generated plasma is investigated in terms of proton and ion emission in the forward and backward directions. The time-of-flight technique, using ion collectors and semiconductor detectors, is used to measure the ion currents and the corresponding velocities and energies. Thomson parabola spectrometer is employed to separate the contribution of the ion emission from single laser shots. A particular attention is given to the proton production in terms of the maximum energy, emission yield, and angular distribution as a function of the laser energy, focal position, target thickness, and composition. Metallic and polymeric targets allow to generate protons with large energy range and different yield, depending on the laser, target composition, and target geometry properties.

  4. Proton emission from thin hydrogenated targets irradiated by laser pulses at 10(16) W∕cm2.

    Science.gov (United States)

    Torrisi, L; Giuffrida, L; Cutroneo, M; Cirrone, P; Picciotto, A; Krasa, J; Margarone, D; Velyhan, A; Laska, L; Ullschmied, J; Wolowski, J; Badziak, J; Rosinski, M

    2012-02-01

    The iodine laser at PALS Laboratory in Prague, operating at 1315 nm fundamental harmonics and at 300 ps FWHM pulse length, is employed to irradiate thin hydrogenated targets placed in vacuum at intensities on the order of 10(16) W∕cm(2). The laser-generated plasma is investigated in terms of proton and ion emission in the forward and backward directions. The time-of-flight technique, using ion collectors and semiconductor detectors, is used to measure the ion currents and the corresponding velocities and energies. Thomson parabola spectrometer is employed to separate the contribution of the ion emission from single laser shots. A particular attention is given to the proton production in terms of the maximum energy, emission yield, and angular distribution as a function of the laser energy, focal position, target thickness, and composition. Metallic and polymeric targets allow to generate protons with large energy range and different yield, depending on the laser, target composition, and target geometry properties.

  5. Technical Note: Immunohistochemical evaluation of mouse brain irradiation targeting accuracy with 3D-printed immobilization device

    Energy Technology Data Exchange (ETDEWEB)

    Zarghami, Niloufar, E-mail: nzargham@uwo.ca; Jensen, Michael D. [Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Talluri, Srikanth; Dick, Frederick A. [Department of Biochemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9 (Canada); Foster, Paula J. [Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario N6A 5K8 (Canada); Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Chambers, Ann F. [Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Oncology, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9 (Canada); Wong, Eugene [Department of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Medical Biophysics, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); Department of Oncology, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada); London Regional Cancer Program, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario N6A 5W9 (Canada)

    2015-11-15

    Purpose: Small animal immobilization devices facilitate positioning of animals for reproducible imaging and accurate focal radiation therapy. In this study, the authors demonstrate the use of three-dimensional (3D) printing technology to fabricate a custom-designed mouse head restraint. The authors evaluate the accuracy of this device for the purpose of mouse brain irradiation. Methods: A mouse head holder was designed for a microCT couch using CAD software and printed in an acrylic based material. Ten mice received half-brain radiation while positioned in the 3D-printed head holder. Animal placement was achieved using on-board image guidance and computerized asymmetric collimators. To evaluate the precision of beam localization for half-brain irradiation, mice were sacrificed approximately 30 min after treatment and brain sections were stained for γ-H2AX, a marker for DNA breaks. The distance and angle of the γ-H2AX radiation beam border to longitudinal fissure were measured on histological samples. Animals were monitored for any possible trauma from the device. Results: Visualization of the radiation beam on ex vivo brain sections with γ-H2AX immunohistochemical staining showed a sharp radiation field within the tissue. Measurements showed a mean irradiation targeting error of 0.14 ± 0.09 mm (standard deviation). Rotation between the beam axis and mouse head was 1.2° ± 1.0° (standard deviation). The immobilization device was easily adjusted to accommodate different sizes of mice. No signs of trauma to the mice were observed from the use of tooth block and ear bars. Conclusions: The authors designed and built a novel 3D-printed mouse head holder with many desired features for accurate and reproducible radiation targeting. The 3D printing technology was found to be practical and economical for producing a small animal imaging and radiation restraint device and allows for customization for study specific needs.

  6. Direct flow separation strategy, to isolate no-carrier-added {sup 90}Nb from irradiated Mo or Zr targets

    Energy Technology Data Exchange (ETDEWEB)

    Radchenko, Valery; Roesch, Frank [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Filosofov, Dmitry V.; Dadakhanov, Jakhongir [Joint Institute of Nuclear Research, Dubna (Russian Federation). Dzhelepov Laboratory of Nuclear Problems; Karaivanov, Dimitar V. [Joint Institute of Nuclear Research, Dubna (Russian Federation). Dzhelepov Laboratory of Nuclear Problems; Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. for Nuclear Research and Nuclear Energy; Marinova, Atanaska [Joint Institute of Nuclear Research, Dubna (Russian Federation). Dzhelepov Laboratory of Nuclear Problems; Sofia Univ. (Bulgaria). Faculty of Chemistry and Pharmacy; Baimukhanova, Ayagoz [Joint Institute of Nuclear Research, Dubna (Russian Federation). Dzhelepov Laboratory of Nuclear Problems; Institute of Nuclear Physics of the Republic of Kazakhstan, Almaty (Kazakhstan)

    2016-11-01

    {sup 90}Nb has an intermediate half-life of 14.6 h, a high positron branching of 53% and optimal β{sup +} emission energy of only E{sub mean} 0.35 MeV per decay. These favorable characteristics suggest it may be a potential candidate for application in immuno-PET. Our recent aim was to conduct studies on distribution coefficients for Zr{sup IV} and Nb{sup V} in mixtures of HCl/H{sub 2}O{sub 2} and HCl/oxalic acid for anion exchange resin (AG 1 x 8) and UTEVA resin to develop a ''direct flow'' separation strategy for {sup 90}Nb. The direct flow concept refers to a separation accomplished using a single eluent on multiple columns, effectively streamlining the separation process and increasing the time efficiency. Finally, we also demonstrated that this separation strategy is applicable to the production of the positron emitter {sup 90}Nb via the irradiation of molybdenum targets and isolation of {sup 90}Nb from the irradiated molybdenum target.

  7. Tritium breeding mock-up experiments containing lithium titanate ceramic pebbles and lead irradiated with DT neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Jakhar, Shrichand; Abhangi, M.; Tiwari, S. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Makwana, R. [Department of Physics, MS University, Vadodara (India); Chaudhari, V.; Swami, H.L.; Danani, C.; Rao, C.V.S.; Basu, T.K. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Mandal, D.; Bhade, Sonali; Kolekar, R.V.; Reddy, P.J. [Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Bhattacharyay, R.; Chaudhuri, P. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2015-06-15

    Highlights: • Breeding benchmark experiment on LLCB TBM in ITER was performed. • Nuclear responses measured are TPR and reaction rate of {sup 115}In(n, n′){sup 115m}In reaction. • Measured responses are compared with calculations by MCNP and FENDL 2.1 library. • TPR measurements agree with calculations in the estimated error bar. • Measured {sup 115}In(n, n′){sup 115m}In reaction rates are underestimated by the calculations. - Abstract: Experiments were conducted with breeding blanket mock-up consisting of two layers of breeder material lithium titanate pebbles and three layers of pure lead as neutron multiplier. The radial dimensions of breeder, neutron multiplier and structural material layers are similar to the current design of the Indian Lead–Lithium cooled Ceramic Breeder (LLCB) blanket. The mock-up assembly was irradiated with 14 MeV neutrons from DT neutron generator. The local tritium production rates (TPR) from {sup 6}Li and {sup 7}Li in breeder layers were measured with the help of two different compositions of Li isotopes (60.69% {sup 6}Li and 7.54% {sup 6}Li) in Li{sub 2}CO{sub 3}. Tritium production in the multiplication layers were also measured with above mentioned two types of pellets to compare the experimental tritium production with calculations. TPR from {sup 6}Li at one location in the breeder layer was also measured by direct online measurement of tritons from {sup 6}Li(n, t){sup 4}He reaction using silicon surface barrier detector and {sup 6}Li to triton converter. Additional verification of neutron spectra (E{sub n} > 0.35 MeV) in the mock-up zones were obtained by measuring {sup 115}In(n, n′){sup 115m}In reaction rate and comparing it with calculated values in all five layers of mock-up. All the measured nuclear responses were compared with transport calculations using code MCNP with FENDL2.1 and FENDL3.0 cross-section libraries. The average C/E ratio for tritium production in enriched Li{sub 2}CO{sub 3} pellets was 1

  8. Target irradiation induced bystander effects between stem-like and non stem-like cancer cells.

    Science.gov (United States)

    Liu, Yu; Kobayashi, Alisa; Maeda, Takeshi; Fu, Qibin; Oikawa, Masakazu; Yang, Gen; Konishi, Teruaki; Uchihori, Yukio; Hei, Tom K; Wang, Yugang

    2015-03-01

    Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in human HT1080 fibrosarcoma cell line were sorted and labeled, then the two cell subtypes were mixed together and chosen separately to be irradiated via a proton microbeam. The radiation-induced bystander effect (RIBE) between the CSCs and NSCCs was measured by imaging 53BP1 foci, a widely used indicator for DNA double strand break (DSB). CSCs were found to be less active than NSCCs in both the generation and the response of bystander signals. Moreover, the nitric oxide (NO) scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two cell subtypes in NO signal response. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute to a further understanding of the out-of-field effect in cancer radiotherapy. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Results of four one-day electron-accelerator irradiations of enriched Mo-100 targets for the production of Mo-99

    Energy Technology Data Exchange (ETDEWEB)

    Chemerisov, S. [Argonne National Lab. (ANL), Argonne, IL (United States); Bailey, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Heltemes, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Jonah, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Makarashvili, V. [Argonne National Lab. (ANL), Argonne, IL (United States); Tkac, P. [Argonne National Lab. (ANL), Argonne, IL (United States); Rotsch, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Virgo, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, G. F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-10-01

    A series of four one-day irradiations was conducted with 100Mo-enriched disk targets. After irradiation, the enriched disks were removed from the target and dissolved. The resulting solution was processed using a NorthStar RadioGenix™ 99mTc generator either at Argonne National Laboratory or at the NorthStar Medical Radioisotopes facility. Runs on the RadioGenix system produced inconsistent analytical results for 99mTc in the Tc/Mo solution. These inconsistencies were attributed to the impurities in the solution or improper column packing. During the irradiations, the performance of the optic transitional radiation (OTR) and infrared cameras was tested in high radiation field. The OTR cameras survived all irradiations, while the IR cameras failed every time. The addition of X-ray and neutron shielding improved camera survivability and decreased the number of upsets.

  10. Distribution characteristic of scattering field for an ellipsoidal target irradiated by an electromagnetic wave from an arbitrary direction

    Institute of Scientific and Technical Information of China (English)

    Li Ying-Le; Huang Ji-Ying; Wang Ming-Jun; Zhang Jia-Tian

    2008-01-01

    It is of great importance for enginsering applications to obtain the expression of scattering field for an ellipsoidal target irradiated by an electromagnetic wave from an arbitrary direction.Literature relevant to this problem is seldom found.In this paper,the scattering field for an ellipsoidal target is presented by utilizing the scale transformation of electromagnetic field and the rotation of coordinate system,with an electromagnetic wave projecting on the target from an arbitrary direction.The obtained result is in good agreement with the solution available from the literature if we consider the scale factors to be unity.Taking a conducting ellipsoidal target for sample,we perform the partial simulations of the ellipsoidat model and a plant leaf model by choosing different scale factors.The obtained results show that the distribution characteristic of scattering field is sensitively affected by the polarization of the incident wave and varies not much with the incident wave angle but changes with the observation point.At some points the scattering energy arrives at its maximum.

  11. Inter- and Intrafraction Target Motion in Highly Focused Single Vocal Cord Irradiation of T1a Larynx Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kwa, Stefan L.S., E-mail: s.kwa@erasmusmc.nl; Al-Mamgani, Abrahim; Osman, Sarah O.S.; Gangsaas, Anne; Levendag, Peter C.; Heijmen, Ben J.M.

    2015-09-01

    Purpose: The purpose of this study was to verify clinical target volume–planning target volume (CTV-PTV) margins in single vocal cord irradiation (SVCI) of T1a larynx tumors and characterize inter- and intrafraction target motion. Methods and Materials: For 42 patients, a single vocal cord was irradiated using intensity modulated radiation therapy at a total dose of 58.1 Gy (16 fractions × 3.63 Gy). A daily cone beam computed tomography (CBCT) scan was performed to online correct the setup of the thyroid cartilage after patient positioning with in-room lasers (interfraction motion correction). To monitor intrafraction motion, CBCT scans were also acquired just after patient repositioning and after dose delivery. A mixed online-offline setup correction protocol (“O2 protocol”) was designed to compensate for both inter- and intrafraction motion. Results: Observed interfraction, systematic (Σ), and random (σ) setup errors in left-right (LR), craniocaudal (CC), and anteroposterior (AP) directions were 0.9, 2.0, and 1.1 mm and 1.0, 1.6, and 1.0 mm, respectively. After correction of these errors, the following intrafraction movements derived from the CBCT acquired after dose delivery were: Σ = 0.4, 1.3, and 0.7 mm, and σ = 0.8, 1.4, and 0.8 mm. More than half of the patients showed a systematic non-zero intrafraction shift in target position, (ie, the mean intrafraction displacement over the treatment fractions was statistically significantly different from zero; P<.05). With the applied CTV-PTV margins (for most patients 3, 5, and 3 mm in LR, CC, and AP directions, respectively), the minimum CTV dose, estimated from the target displacements observed in the last CBCT, was at least 94% of the prescribed dose for all patients and more than 98% for most patients (37 of 42). The proposed O2 protocol could effectively reduce the systematic intrafraction errors observed after dose delivery to almost zero (Σ = 0.1, 0.2, 0.2 mm). Conclusions: With

  12. Estimations of neutron yield from beryllium target irradiated by SPring-8 hard synchrotron radiation

    CERN Document Server

    Gryaznykh, D A; Plokhoi, V V

    2000-01-01

    The possibility of creating a neutron source based on ''SPring-8'' synchrotron radiation interaction with beryllium targets is discussed. The possible neutron yield is estimated to be of order 10 sup 1 sup 2 s sup - sup 1 .

  13. A method to achieve rapid localised deep heating in a laser irradiated solid density target

    CERN Document Server

    Schmitz, Holger

    2016-01-01

    Rapid heating of small buried regions by laser generated fast electrons may be useful for applications such as XUV radiation sources or as drivers for shock experiments. In non-structured targets the heating profile possesses a global maximum near the front surface. This paper presents a new target design that uses resistive guiding to concentrate the fast electron current density at a finite depth inside the target. The choice of geometry uses principles of non-imaging optics. A global temperature maximum at depths up to 50{\\mu}m into the target is achieved. Although theoretical calculations suggest that small source sizes should perform better than large ones, simulations show that a large angular spread at high intensities results in significant losses of the fast electrons to the sides. A systematic parameter scan suggests an optimal laser intensity. A ratio of 1.6 is demonstrated between the maximum ion temperature and the ion temperature at the front surface.

  14. Strong soft X-ray emission from a double-stream gas puff target irradiated with a nanosecond Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Fiedorowicz, H.; Bartnik, A.; Rakowski, R.; Szczurek, M. [Military Univ. of Technology, Warsaw (Poland). Inst. of Optoelectronics; Daido, H.; Suzuki, M.; Yamagami, S.; Choi, I.W.; Tang, H.J. [Osaka Univ., Suita (Japan). Inst. of Laser Engineering

    2001-07-01

    Soft X-ray emission from a new double-stream gas puff target irradiated with a nanosecond, high-power Nd:YAG laser pulse has been studied. The target was formed by pulsed injection of gas into a hollow gas stream made from helium by using a double-nozzle setup. Strong X-ray emissions near 10 nm from the double-stream krypton/helium, near 11 nm from the xenon/helium, and at 13 nm from the oxygen/helium targets were observed. The emission from the double-stream gas puff target was several times higher as compared to the ordinary gas puff targets, and comparable to the emission from the solid targets irradiated in the same conditions. (orig.)

  15. Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets

    Energy Technology Data Exchange (ETDEWEB)

    Neumayer, P.; Gumberidze, A.; Hochhaus, D. C. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, 60438 Frankfurt am Main (Germany); Aurand, B.; Stoehlker, T. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Costa Fraga, R. A.; Kalinin, A. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Ecker, B. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Kaluza, M. C. [Helmholtz Institute Jena, 07743 Jena (Germany); IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Kuehl, T. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Polz, J. [IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Reuschl, R. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Winters, D.; Winters, N.; Yin, Z. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany)

    2012-12-15

    We report on an experiment irradiating individual argon droplets of 20 {mu}m diameter with laser pulses of several Joule energy at intensities of 10{sup 19} W/cm{sup 2}. K-shell emission spectroscopy was employed to determine the hot electron energy fraction and the time-integrated charge-state distribution. Spectral fitting indicates that bulk temperatures up to 160 eV are reached. Modelling of the hot-electron relaxation and generation of K-shell emission with collisional hot-electron stopping only is incompatible with the experimental results, and the data suggest an additional ultra-fast (sub-ps) heating contribution. For example, including resistive heating in the modelling yields a much better agreement with the observed final bulk temperature and qualitatively reproduces the observed charge state distribution.

  16. Target irradiation induced bystander effects between stem-like and non stem-like cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yu [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Kobayashi, Alisa [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Maeda, Takeshi [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Fu, Qibin [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Oikawa, Masakazu [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Yang, Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Konishi, Teruaki, E-mail: tkonishi@nirs.go.jp [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Uchihori, Yukio [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); and others

    2015-03-15

    Highlights: • Existence of radiation induced bystander effects (RIBE) between cancer stem-like cells (CSCs) and non stem-like cancer cells (NSCCs) in human fibrosarcoma HT1080 cells. • Existence of significant difference in generation and response of bystander signals between CSCs and NSCCs. • CSCs are significantly less sensitive to NO scavenger than that of NSCCs in terms of DNA double strand breaks induced by RIBE. - Abstract: Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in human HT1080 fibrosarcoma cell line were sorted and labeled, then the two cell subtypes were mixed together and chosen separately to be irradiated via a proton microbeam. The radiation-induced bystander effect (RIBE) between the CSCs and NSCCs was measured by imaging 53BP1 foci, a widely used indicator for DNA double strand break (DSB). CSCs were found to be less active than NSCCs in both the generation and the response of bystander signals. Moreover, the nitric oxide (NO) scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two cell subtypes in NO signal response. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute to a further understanding of the out-of-field effect in cancer radiotherapy.

  17. Targeted inactivation of GPR26 leads to hyperphagia and adiposity by activating AMPK in the hypothalamus.

    Directory of Open Access Journals (Sweden)

    Daohong Chen

    Full Text Available G-protein coupled receptor 26 (GPR26 is a brain-specific orphan GPCR with high expression in the brain region that controls satiety. Depletion of GPR26 has been shown to increase fat storage in C. elegans, whereas GPR26 deficiency in the hypothalamus is associated with high genetic susceptibility to the onset of obesity in mice. However, the metabolic function of GPR26 in mammals remains elusive. Herein, we investigated a role of GPR26 in regulating energy homeostasis by generating mice with targeted deletion of the GPR26 gene. We show that GPR26 deficiency causes hyperphagia and hypometabolism, leading to early onset of diet-induced obesity. Accordingly, GPR26 deficiency also caused metabolic complications commonly associated with obesity, including glucose intolerance, hyperinsulinemia, and dyslipidemia. Moreover, consistent with hyperphagia in GPR26 null mice, GPR26 deficiency significantly increased hypothalamic activity of AMPK, a key signaling event that stimulates appetite. In further support of a regulatory role of GPR26 in satiety, GPR26 knockout mice also demonstrate hypersensitivity to treatment of rimonabant, an endocannabinoid receptor-1 antagonist commonly used to treat obesity by suppressing appetite in humans. Together, these findings identified a key role of GPR26 as a central regulator of energy homeostasis though modulation of hypothalamic AMPK activation.

  18. IdealKnock: A framework for efficiently identifying knockout strategies leading to targeted overproduction.

    Science.gov (United States)

    Gu, Deqing; Zhang, Cheng; Zhou, Shengguo; Wei, Liujing; Hua, Qiang

    2016-04-01

    In recent years, computer aided redesigning methods based on genome-scale metabolic network models (GEMs) have played important roles in metabolic engineering studies; however, most of these methods are hindered by intractable computing times. In particular, methods that predict knockout strategies leading to overproduction of desired biochemical are generally unable to do high level prediction because the computational time will increase exponentially. In this study, we propose a new framework named IdealKnock, which is able to efficiently evaluate potentials of the production for different biochemical in a system by merely knocking out pathways. In addition, it is also capable of searching knockout strategies when combined with the OptKnock or OptGene framework. Furthermore, unlike other methods, IdealKnock suggests a series of mutants with targeted overproduction, which enables researchers to select the one of greatest interest for experimental validation. By testing the overproduction of a large number of native metabolites, IdealKnock showed its advantage in successfully breaking through the limitation of maximum knockout number in reasonable time and suggesting knockout strategies with better performance than other methods. In addition, gene-reaction relationship is well considered in the proposed framework.

  19. A study of the neutron irradiation effects on the susceptibility to embrittlement of A316L and T91 steels in lead-bismuth eutectic

    Energy Technology Data Exchange (ETDEWEB)

    Sapundjiev, D. [TCH, SCK-CEN, Boeretang 200, Mol, B-2400 (Belgium)]. E-mail: danislav.sapundjiev@sckcen.be; Al Mazouzi, A. [TCH, SCK-CEN, Boeretang 200, Mol, B-2400 (Belgium); Van Dyck, S. [TCH, SCK-CEN, Boeretang 200, Mol, B-2400 (Belgium)

    2006-09-15

    The effects of neutron irradiation on the susceptibility to liquid metal embrittlement of two primary selected materials for MYRRHA project an accelerator driven system (ADS), was investigated by means of slow strain rate tests (SSRT). The latter were carried out at 200 deg. C in nitrogen and in liquid Pb-Bi at a strain rate of 5 x 10{sup -6} s{sup -1}. The small tensile specimens were irradiated at the BR-2 reactor in the MISTRAL irradiation rig at 200 deg. C for 3 reactor cycles to reach a dose of about 1.50 dpa. The SSR tests were carried out under poor and under dissolved oxygen conditions ({approx}1.5 x 10{sup -12} wt% dissolved oxygen) which at this temperature will favour formation of iron and chromium oxides. Although both materials differ in structure (fcc for A316L against bcc for T91), their flow behaviour in contact with liquid lead bismuth eutectic before and after irradiation is very similar. Under these testing conditions none of them was found susceptible to liquid metal embrittlement (LME)

  20. Target size analysis by radiation inactivation: a large capacity tube rack for irradiation in a Gammacell 220.

    Science.gov (United States)

    Beauregard, G; Giroux, S; Potier, M

    1983-07-15

    Target size analysis by radiation inactivation is now a well-established method to study structure-function relationships in biologically active macromolecules without prior purification or even solubilization. Recently, it was reported that a relatively low-dose-rate but commonly available gamma source such as the Gammacell 220 (Atomic Energy of Canada, Ltd.) can be used to carry out radiation inactivation experiments providing it is appropriately calibrated with enzymes of known radiation sensitivities (G. Beauregard and M. Potier (1982) Anal. Biochem. 122, 379-384). In this report, a tube rack designed to fit into the irradiation chamber of the Gammacell 220 which allows five experiments (at 30 tubes per experiment) to be carried out simultaneously with both standard and unknown samples is described. The dose rates delivered at different positions in the rack were determined by irradiating rat liver cytosolic neuraminidase, an enzyme of known radiation sensitivity. A better than 2.7% agreement was obtained between experimental dose rate and computed values from isodose curves previously published by other authors (O. A. Curzio and H. O. Quaranta (1982) Int. J. Appl. Radiat. Isot. 33, 1-3).

  1. Secondary neutron production from thick Pb target by light particle irradiation

    CERN Document Server

    Adloff, J C; Debeauvais, M; Fernández, F; Krivopustov, M; Kulakov, B A; Sosnin, A; Zamani, M

    1999-01-01

    Neutron multiplicities from spallation neutron sources were measured by Solid State Nuclear Track Detectors. Light particles as protons, deuterons and alphas in the GeV range were used on Pb targets. For neutron thermalization the targets were covered by 6 cm paraffin moderator. Neutron multiplicity distributions were studied inside and on the moderator surface. Comparison of SSNTDs results were made for thermal-epithermal neutrons with sup 1 sup 3 sup 9 La activation method as well as with Dubna DCM/CEM code. Discussion including previous sup 1 sup 2 C results are given.

  2. Production of isotopes and isomers with irradiation of Z = 47–50 targets by 23-MeV bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, S. A., E-mail: karamian@nrmail.jinr.ru [Joint Institute for Nuclear Research (Russian Federation); Carroll, J. J. [US Army Research Laboratory (United States); Aksenov, N. V.; Albin, Yu. A.; Belov, A. G.; Bozhikov, G. A.; Dmitriev, S. N.; Starodub, G. Ya. [Joint Institute for Nuclear Research (Russian Federation)

    2015-09-15

    The irradiations of Ag to Sn targets by bremsstrahlung generated with 23-MeV electron beams are performed at the MT-25 microtron. Gamma spectra of the induced activities have been measured and the yields of all detected radionuclides and isomers are carefully measured and analyzed. A regular dependence of yields versus changed reaction threshold is confirmed. Many isomers are detected and the suppression of the production probability is observed with growing product spin. Special peculiarities for the isomer-to-ground state ratios were deduced for the {sup 106m}Ag, {sup 108m}Ag, {sup 113m}In, {sup 115m}In, and {sup 123m}Sn isomers. The production of such nuclides as {sup 108m}Ag, {sup 115m}In, {sup 117g}In, and {sup 113m}Cd is of interest for applications, especially when economic methods are available.

  3. FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Megan E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bowers, Delbert L. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO42- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

  4. Suprathermal electron production in laser-irradiated Cu targets characterized by combined methods of x-ray imaging and spectroscopy

    Science.gov (United States)

    Renner, O.; Šmíd, M.; Batani, D.; Antonelli, L.

    2016-07-01

    In a series of experiments performed with laser-irradiated planar targets at the PALS laser facility, the generation of suprathermal electrons has been studied at conditions relevant for the development of a shock ignition approach to inertial confinement fusion. A simultaneous application of high-collection-efficiency K-shell imaging with high resolution x-ray spectroscopy offers a novel approach to hot electron diagnosis at non-coated or moderately coated, medium-atomic-number targets, where the contribution of suprathermal-electron-generated, frequency-shifted Kα emission from highly ionized atoms cannot be neglected. Based on experimental data provided by these combined techniques and their interpretation via collisional-radiative atomic codes and Monte Carlo modeling of hot electron energy deposition in heated Cu targets, the fraction of the energy converted to hot electrons at laser intensities  ≈1016 W cm-2 was measured to be at the level of 0.1-0.8%. The higher values of conversion efficiency found for frequency tripled radiation support a theoretical conjecture of enhanced laser energy absorption by a resonance mechanism and its transport to a flow of fast electrons.

  5. Prediction of production of 22Na in a gas-cell target irradiated by protons using Monte Carlo tracking

    Science.gov (United States)

    Eslami, M.; Kakavand, T.; Mirzaii, M.; Rajabifar, S.

    2015-01-01

    The 22Ne(p,n)22Na is an optimal reaction for the cyclotron production of 22Na. This work tends to monitor the proton induced production of 22Na in a gas-cell target, containing natural and enriched neon gas, using Monte Carlo method. The excitation functions of reactions are calculated by both TALYS-1.6 and ALICE/ASH codes and then the optimum energy range of projectile for the high yield production is selected. A free gaseous environment of neon at a particular pressure and temperature is prearranged and the proton beam is transported within it using Monte Carlo codes MCNPX and SRIM. The beam monitoring performed by each of these codes indicates that the gas-cell has to be designed as conical frustum to reach desired interactions. The MCNPX is also employed to calculate the energy distribution of proton in the designed target and estimation of the residual nuclei during irradiation. The production yield of 22Na in 22Ne(p,n)22Na and natNe(p,x)22Na reactions are estimated and it shows a good agreement with the experimental results. The results demonstrate that Monte Carlo makes available a beneficial manner to design and optimize the gas targets as well as calibration of detectors, which can be used for the radionuclide production purposes.

  6. In-target electron thermalization by the Weibel instability during intense irradiation of a thin aluminum foil

    Science.gov (United States)

    Fuchs, J.; Ruyer, C.; Albertazzi, B.; Lancia, L.; Dervieux, V.; Antici, P.; Bocker, J.; Chen, S. N.; Nakatsutsumi, M.; Romagnani, L.; Shepherd, R.; Swantusch, M.; Borghesi, M.; Willi, O.; Pepin, H.; Grech, M.; Riconda, C.; Gremillet, L.

    2015-11-01

    Proton-radiography of the electromagnetic fields developing after irradiation of a 3 μm-thick Al foil by a high-intensity laser (5 ×1019 W.cm-2, 700fs, 8 μm focal spot) was performed at the Titan facility. The obtained radiographs evidence filamentary structures which develop inside the dense target, 300 μ m away from the focal spot, a few picoseconds after the laser drive. We will demonstrate that the radiographs' structures are due to magnetic fields triggered by the so-called Weibel instability, inside the dense target. For this purpose, large scale particle-in-cell simulations of hot electrons thermalization in a dense, cold and collisional target have been performed. They demonstrate the ability of the laser-heated electrons to sustain a strong temperature anisotropy during their relaxation in the thin foil. This hot electron anisotropy results in a Weibel instability, thus triggering magnetic fluctuations of spectrum consistent with the experiment over 10 picoseconds.

  7. Mechanism of pain relief by low-power infrared irradiation: ATP is an IR-target molecule in nociceptive neurons.

    Science.gov (United States)

    Yachnev, Igor L; Plakhova, Vera B; Podzorova, Svetlana A; Shelykh, Tatiana N; Rogachevsky, Ilya V; Krylov, Boris V

    2012-01-01

    Effects of infrared (IR) radiation generated by a low-power CO2-laser on the membrane of cultured dissociated nociceptive neurons of newborn rat spinal ganglia were investigated using the whole-cell patch-clamp method. Low-power IR radiation diminished the voltage sensitivity of activation gating machinery of slow sodium channels (Na(v)1.8). Ouabain known to block both transducer and pumping functions of Na+,K+-ATPase eliminated IR irradiation effects. The molecular mechanism of interaction of CO2-laser radiation with sensory membrane was proposed. The primary event of this interaction is the process of energy absorption by ATP molecules. The transfer of vibrational energy from Na+,K+- ATPase-bound and vibrationally excited ATP molecules to Na+,K+-ATPase activates this enzyme and converts it into a signal transducer. This effect leads to a decrease in the voltage sensitivity of Na(v)1.8 channels. The effect of IR-radiation was elucidated by the combined application of a very sensitive patch-clamp method and an optical facility with a controlled CO2-laser. As a result, the mechanism of interaction of non-thermal low-power IR radiation with the nociceptive neuron membrane is suggested.

  8. Target irradiation facility and targetry development at 160 MeV proton beam of Moscow linac

    CERN Document Server

    Zhuikov, B L; Konyakhin, N A; Vincent, J

    1999-01-01

    A facility has been built and successfully operated with the 160 MeV proton beam of Moscow Meson factory LINAC, Institute for Nuclear Research (INR) of Russian Academy of Science, Troitsk. The facility was created for various isotope production goals as well as for fundamental nuclear investigations at high intensity beam (100 mu A and more). An important part of the facility targetry system is a high-intensity beam monitoring collimator device. Measurements of the temperature distribution between collimator sectors, cooling water flow and temperature, and the beam current, provide an opportunity to compute beam losses and beam position. The target holder design allows easy insertion by manipulator and simultaneous bombardment of several different targets of various types and forms, and variation of proton energy on each target over a wide range below 160 MeV. The main target utilized for commercial sup 8 sup 2 Sr isotope production is metallic rubidium in a stainless-steel container. A regular wet chemistry ...

  9. Waste Treatment of Acidic Solutions from the Dissolution of Irradiated LEU Targets for 99-Mo Production

    Energy Technology Data Exchange (ETDEWEB)

    Bakel, Allen J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Conner, Cliff [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-10-01

    One of the missions of the Reduced Enrichment for Research and Test Reactors (RERTR) program (and now the National Nuclear Security Administrations Material Management and Minimization program) is to facilitate the use of low enriched uranium (LEU) targets for 99Mo production. The conversion from highly enriched uranium (HEU) to LEU targets will require five to six times more uranium to produce an equivalent amount of 99Mo. The work discussed here addresses the technical challenges encountered in the treatment of uranyl nitrate hexahydrate (UNH)/nitric acid solutions remaining after the dissolution of LEU targets. Specifically, the focus of this work is the calcination of the uranium waste from 99Mo production using LEU foil targets and the Modified Cintichem Process. Work with our calciner system showed that high furnace temperature, a large vent tube, and a mechanical shield are beneficial for calciner operation. One- and two-step direct calcination processes were evaluated. The high-temperature one-step process led to contamination of the calciner system. The two-step direct calcination process operated stably and resulted in a relatively large amount of material in the calciner cup. Chemically assisted calcination using peroxide was rejected for further work due to the difficulty in handling the products. Chemically assisted calcination using formic acid was rejected due to unstable operation. Chemically assisted calcination using oxalic acid was recommended, although a better understanding of its chemistry is needed. Overall, this work showed that the two-step direct calcination and the in-cup oxalic acid processes are the best approaches for the treatment of the UNH/nitric acid waste solutions remaining from dissolution of LEU targets for 99Mo production.

  10. Conversion of Molybdenum-99 production process to low enriched uranium: Neutronic and thermal hydraulic analyses of HEU and LEU target plates for irradiation in Pakistan Research Reactor-1

    Science.gov (United States)

    Mushtaq, Ahmad; Iqbal, Masood; Bokhari, Ishtiaq Hussain; Mahmood, Tayyab; Muhammad, Atta

    2012-09-01

    Technetium-99m, the daughter product of Molybdenum-99 is the most widely needed radionuclide for diagnostic studies in Pakistan. Molybdenum-99 Production Facility has been established at PINSTECH. Highly enriched uranium (93% 235U) U/Al alloy targets have been irradiated in Pakistan Research Reactor-1 (PARR-1) for the generation of fission Mo-99, while basic dissolution technique is used for separation of Mo-99 from target matrix activity. In line with the international objective of minimizing and eventually eliminating the use of HEU in civil commerce, national and international efforts have been underway to shift the production of medical isotopes from HEU to LEU (LEU; uranium is needed. LEU aluminum uranium dispersion target has been developed, which may replace existing HEU aluminum/uranium alloy targets for production of 99Mo using basic dissolution technique. Neutronic and thermal hydraulic calculations were performed for safe irradiation of targets in the core of PARR-1.

  11. Targeted bone marrow irradiation in the conditioning of high-risk leukaemia prior to stem cell transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Reske, S.N.; Buchmann, I.; Seitz, U.; Glatting, G.; Neumaier, B.; Kotzerke, J.; Buck, A. [Ulm Univ. (Germany). Abt. Nuklearmedizin; Bunjes, D.; Doehner, H. [Abteilung Innere Medizin III, Haematologie und Onkologie, Universitaetsklinikum Ulm (Germany); Martin, H.; Bergmann, L. [Klinik fuer Haematologie und Onkologie, Johann-Wolfgang-Goethe Universitaet Frankfurt (Germany)

    2001-07-01

    Disease recurrence following stem cell transplantation (SCT) remains a major problem. Despite the sensitivity of leukaemias to chemotherapy and irradiation, conventional conditioning before SCT is limited by significant organ toxicity. Targeted irradiation of bone marrow and spleen by radioimmunotherapy may provide considerable dose escalation, with limited toxicity to non-target organs. In this study, 27 patients with high-risk or relapsing leukaemia were treated with rhenium-188-labelled CD66a,b,c,e radioimmunoconjugates ({sup 188}Re-mAb) specific for normal bone marrow in addition to conventional conditioning with high-dose chemotherapy and 12 Gy total body irradiation prior to SCT. A mean activity of 10.2{+-}2.1 (range 6.9-15.8) GBq {sup 188}Re-mAb was administered intravenously. Acute side-effects were assessed according to the CTC classification and patient outcome was determined. Mean radiation doses (Gy; range in parentheses) to relevant organs and whole body were as follows: 13.1 (6.5-22) to bone marrow, 11.6 (1.7-31.1) to spleen, 5.0 (2.0-11.7) to liver, 7.0 (2.3-11.6) to kidneys, 0.7 (0.3-1.3) to lungs and 1.4 (0.8-2.1) to the whole body. Stem cells engrafted in all patients within 9-18 days post SCT. Acute organ toxicity of grade II or less was observed. During follow-up for 25.4{+-}5.3 (range 18-34) months, 4/27 (15%) patients died from relapse, and 9/27 (33%) from transplantation-related complications. Fourteen patients (52%) are still alive and in ongoing complete clinical remission. Radioimmunotherapy with the bone marrow-seeking {sup 188}Re-labelled CD66 mAb can double the dose to bone marrow and spleen without undue extramedullary acute organ toxicity, when given in addition to high-dose chemotherapy and 12 Gy TBI before allogeneic SCT. This intensified conditioning regimen may reduce the relapse rate of high-risk leukaemia. (orig.)

  12. Evaluation of the cross-sections of threshold reactions leading to the production of long-lived radionuclides during irradiation of steels by thermonuclear spectrum neutrons

    CERN Document Server

    Blokhin, A I; Manokhin, V N; Mikhajlyukova, M V; Nasyrova, S M; Skripova, M V

    2001-01-01

    The present paper analyses and evaluates the cross-sections of threshold reactions leading to the production of long-lived radionuclides during the irradiation, by thermonuclear spectrum neutrons, of steels containing V, Ti, Cr, Fe and Ni. On the basis of empirical systematics. a new evaluation of the (n,2n), (n,p), (n,np), (n,alpha) and (n,n alpha) excitation functions is made for all isotopes of V, Ti, Cr, Fe and Ni and for intermediate isotopes produced in the chain from irradiated isotopes up to production of the long-lived radionuclides sup 3 sup 9 Ar, sup 4 sup 2 Ar, sup 4 sup 1 Ca, sup 5 sup 3 Mn, sup 6 sup 0 Fe, sup 6 sup 0 Co, sup 5 sup 9 Ni and sup 6 sup 3 Ni. A comparison is made with the experimental and other evaluated data.

  13. A quantitative and comparative study of radionuclidic and chemical impurities in water samples irradiated in a niobium target with Havar vs. niobium-sputtered Havar as entrance foils

    Energy Technology Data Exchange (ETDEWEB)

    Avila-Rodriguez, Miguel A. [Edmonton PET Centre, Cross Cancer Institute, Alberta Cancer Board, 11560 University Avenue, Edmonton, AB, T6G 1Z2 (Canada)], E-mail: Miguel.Avila-Rodriguez@utu.fi; Wilson, John S.; McQuarrie, Steve A. [Edmonton PET Centre, Cross Cancer Institute, Alberta Cancer Board, 11560 University Avenue, Edmonton, AB, T6G 1Z2 (Canada)

    2008-12-15

    Enriched and natural abundance water samples were irradiated in a niobium (Nb) chamber target with Havar and Nb-sputtered Havar foils. Irradiations were performed with 17.5 MeV protons at currents from 35 to 100 {mu}A lasting for 1-2.5 h. Radionuclidic and chemical (cationic) impurities were determined via gamma spectroscopy and ICP-MS, respectively. Anionic impurities were evaluated by ion chromatography. Impurities in water samples irradiated with the Havar-Nb foils were much lower than the samples irradiated with an unmodified Havar foil. No significant differences were observed in the impurity levels between samples of H{sub 2}{sup 18}O-enriched and natural abundance water. Radionuclidic impurities were observed to decrease after 3-4 irradiations on a fresh Havar entrance foil, and reached a constant value for subsequent irradiations with the same integrated current. For targets covered with Havar foil, radionuclidic impurities were found to be proportional to the beam-integrated current regardless of the beam power and, unexpectedly, dependant of the beam power when using a Havar-Nb foil.

  14. A quantitative and comparative study of radionuclidic and chemical impurities in water samples irradiated in a niobium target with Havar vs. niobium-sputtered Havar as entrance foils.

    Science.gov (United States)

    Avila-Rodriguez, Miguel A; Wilson, John S; McQuarrie, Steve A

    2008-12-01

    Enriched and natural abundance water samples were irradiated in a niobium (Nb) chamber target with Havar and Nb-sputtered Havar foils. Irradiations were performed with 17.5MeV protons at currents from 35 to 100microA lasting for 1-2.5h. Radionuclidic and chemical (cationic) impurities were determined via gamma spectroscopy and ICP-MS, respectively. Anionic impurities were evaluated by ion chromatography. Impurities in water samples irradiated with the Havar-Nb foils were much lower than the samples irradiated with an unmodified Havar foil. No significant differences were observed in the impurity levels between samples of H(2)(18)O-enriched and natural abundance water. Radionuclidic impurities were observed to decrease after 3-4 irradiations on a fresh Havar entrance foil, and reached a constant value for subsequent irradiations with the same integrated current. For targets covered with Havar foil, radionuclidic impurities were found to be proportional to the beam-integrated current regardless of the beam power and, unexpectedly, dependant of the beam power when using a Havar-Nb foil.

  15. Prediction of production of {sup 22}Na in a gas-cell target irradiated by protons using Monte Carlo tracking

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, M., E-mail: mohammad.eslami25@yahoo.com [Department of Physics, Faculty of Science, University of Zanjan, Zengan (Zanjan) (Iran, Islamic Republic of); Kakavand, T. [Department of Physics, Faculty of Science, University of Zanjan, Zengan (Zanjan) (Iran, Islamic Republic of); Department of Physics, Faculty of Science, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of); Mirzaii, M.; Rajabifar, S. [Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, AEOI, Karaj (Iran, Islamic Republic of)

    2015-01-01

    Highlights: • Angular distribution of the proton beam in a gaseous environment. • Particle energy distribution profile and proton flux within gas-cell target with MCNPX. • Detection of the residual nuclei during the nuclear reactions. • Estimation of production yield for {sup 22,nat}Ne(p,x){sup 22}Na reactions. - Abstract: The {sup 22}Ne(p,n){sup 22}Na is an optimal reaction for the cyclotron production of {sup 22}Na. This work tends to monitor the proton induced production of {sup 22}Na in a gas-cell target, containing natural and enriched neon gas, using Monte Carlo method. The excitation functions of reactions are calculated by both TALYS-1.6 and ALICE/ASH codes and then the optimum energy range of projectile for the high yield production is selected. A free gaseous environment of neon at a particular pressure and temperature is prearranged and the proton beam is transported within it using Monte Carlo codes MCNPX and SRIM. The beam monitoring performed by each of these codes indicates that the gas-cell has to be designed as conical frustum to reach desired interactions. The MCNPX is also employed to calculate the energy distribution of proton in the designed target and estimation of the residual nuclei during irradiation. The production yield of {sup 22}Na in {sup 22}Ne(p,n){sup 22}Na and {sup nat}Ne(p,x){sup 22}Na reactions are estimated and it shows a good agreement with the experimental results. The results demonstrate that Monte Carlo makes available a beneficial manner to design and optimize the gas targets as well as calibration of detectors, which can be used for the radionuclide production purposes.

  16. Scattered light diagnostics of overdense plasma cavity in solid targets irradiated by an ultraintense laser pulse.

    Science.gov (United States)

    Andreev, A A; Zhidkov, A G; Uesaka, M; Kinoshita, K; Platonov, K Yu

    2002-09-01

    The light scattered backward from a target illuminated by ultraintense laser pulses carries important information about the nonlinear laser-plasma interaction. We analyze the usefulness of this information by plasma corona analysis with the help of an analytical model we developed, and particle-in-cell simulation. The spectrum of scattered light is shown to be shifted, to be broadened, and to be modulated, in comparison with the initial laser spectrum, and the spectral shift is an indicator of laser pulse contrast ratio.

  17. Production of krypton and xenon isotopes in thick stony and iron targets isotropically irradiated with 1600 MeV protons

    CERN Document Server

    Gilabert, E; Lavielle, B; Leya, I; Michel, R; Neumann, S

    2002-01-01

    Two spherical targets made of gabbro with a radius of 25 cm and of steel with a radius of 10 cm were irradiated isotropically with 1600 MeV protons at the SATURNE synchrotron at Laboratoire National Saturne (LNS)/CEN Saclay, in order to simulate the production of nuclides in meteorites induced by galactic cosmic-ray protons in space. These experiments supply depth-dependent production rate data for a wide range of radioactive and stable isotopes in up to 28 target elements. In this paper, we report results for /sup 78/Kr, /sup 80-86/Kr isotopes in Rb, Sr, Y and Zr and for /sup 124/Xe, /sup 126/Xe, /sup 128-132/Xe, /sup 134/Xe, /sup 136/Xe isotopes in Ba and La. Krypton and xenon concentrations have been measured at different depths in the spheres by using conventional mass spectrometry. Based on Monte-Carlo techniques, theoretical production rates are calculated by folding depth-dependent spectra of primary and secondary protons and secondary neutrons with the excitation functions of the relevant nuclear reac...

  18. A role for fragment-based drug design in developing novel lead compounds for central nervous system targets

    Directory of Open Access Journals (Sweden)

    Michael J. Wasko

    2015-09-01

    Full Text Available Hundreds of millions of U.S. dollars are invested in the research and development of a single drug. Lead compound development is an area ripe for new design strategies. Therapeutic lead candidates have been traditionally found using high-throughput in vitro pharmacologic screening, a costly method for assaying thousands of compounds. This approach has recently been augmented by virtual screening, which employs computer models of the target protein to narrow the search for possible leads. A variant of virtual screening is fragment-based drug design, an emerging in silico lead discovery method that introduces low molecular weight fragments, rather than intact compounds, into the binding pocket of the receptor model. These fragments serve as starting points for growing the lead candidate. Current efforts in virtual fragment-based drug design within central nervous system (CNS targets are reviewed, as is a recent rule-based optimization strategy in which new molecules are generated within a 3D receptor binding pocket using the fragment as a scaffold. This process places special emphasis on creating synthesizable molecules but also exposes computational questions worth addressing. Fragment-based methods provide a viable, relatively low-cost alternative for therapeutic lead discovery and optimization that can be applied to CNS targets to augment current design strategies.

  19. HDR monotherapy for prostate cancer: A simulation study to determine the effect of catheter displacement on target coverage and normal tissue irradiation

    NARCIS (Netherlands)

    I.-K.K. Kolkman-Deurloo (Inger-Karina); M.A. Roos (Martin); S. Aluwini (Shafak)

    2011-01-01

    textabstractPurpose: The aim of this study was to systematically analyse the effect of catheter displacements both on target coverage and normal tissue irradiation in fractionated high dose rate (HDR) prostate brachytherapy, using a simulation study, and to define tolerances for catheter displacemen

  20. A new approach to long-term reconstruction of the solar irradiance leads to large historical solar forcing

    CERN Document Server

    Shapiro, A I; Rozanov, E; Schoell, M; Haberreiter, M; Shapiro, A V; Nyeki, S

    2011-01-01

    The variable Sun is the most likely candidate for natural forcing of past climate change on time scales of 50 to 1000 years. Evidence for this understanding is that the terrestrial climate correlates positively with solar activity. During the past 10,000 years, the Sun has experienced substantial variations in activity and there have been numerous attempts to reconstruct solar irradiance. While there is general agreement on how solar forcing varied during the last several hundred years --- all reconstructions are proportional to the solar activity --- there is scientific controversy on the magnitude of solar forcing. We present a reconstruction of the Total and Spectral Solar Irradiance covering 130 nm--10 $\\mu$m from 1610 to the present with annual resolution and for the Holocene with 22-year resolution. We assume that the minimum state of the quiet Sun in time corresponds to the observed quietest area on the present Sun. Then we use available long-term proxies of the solar activity, which are $^{10}$Be isot...

  1. Adipose tissue: another target organ for lead accumulation? A study on Sardinian children (Italy).

    Science.gov (United States)

    Vallascas, Elisabetta; De Micco, Alessandro; Deiana, Fabrizio; Banni, Sebastiano; Sanna, Emanuele

    2013-01-01

    This study analyzes the relationship between lead levels and adipose tissue in Sardinian children. As an environmental pollutant, lead occurs in two different chemical forms: inorganic and organic lead; organic lead is present in the environment mainly as lead-alkyls (tetramethyl and tetraethyl lead). The lead-alkyls are characterized by their liposolubility; because of this characteristic, the behavior of organic Pb in the organism is similar to that of persistent organic pollutants (POPs). In fact, the high liposolubility of POPs, synthetic chemical substances highly resistant to biodegradation in both the environment and the human body, gives them a preferential tendency to accumulate in adipose tissue. The study sample consisted of 759 children between 11 and 15 years resident in various municipalities of Sardinia. Hair lead levels (PbH) were used as the biomarker of exposure, while several anthropometric indexes were adopted to evaluate the adipose tissue: weight, body mass index, waist circumference, waist to hip circumference ratio, and sum of skinfolds (Σskf). The results of the multivariate ridge regression analysis, controlling for sex and age, show a significant positive relationship between logPbH and logΣskf but not the other adiposity indicators. This results suggests that organic lead tends to accumulate in adipose tissue, although it would be appropriate to measure lead levels in the adipose tissue itself in order to verify the results. Hence this tissue could be considered a possible new biological matrix for the evaluation of environmental lead exposure. Copyright © 2013 Wiley Periodicals, Inc.

  2. Neutronics, steady-state, and transient analyses for the Poland MARIA reactor for irradiation testing of LEU lead test fuel assemblies from CERCA : ANL independent verification results.

    Energy Technology Data Exchange (ETDEWEB)

    Garner, P. L.; Hanan, N. A. (Nuclear Engineering Division)

    2011-06-07

    The MARIA reactor at the Institute of Atomic Energy (IAE) in Swierk (30 km SE of Warsaw) in the Republic of Poland is considering conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel assemblies (FA). The FA design in MARIA is rather unique; a suitable LEU FA has never been designed or tested. IAE has contracted with CERCA (the fuel supply portion of AREVA in France) to supply 2 lead test assemblies (LTA). The LTAs will be irradiated in MARIA to burnup level of at least 40% for both LTAs and to 60% for one LTA. IAE may decide to purchase additional LEU FAs for a full core conversion after the test irradiation. The Reactor Safety Committee within IAE and the National Atomic Energy Agency in Poland (PAA) must approve the LTA irradiation process. The approval will be based, in part, on IAE submitting revisions to portions of the Safety Analysis Report (SAR) which are affected by the insertion of the LTAs. (A similar process will be required for the full core conversion to LEU fuel.) The analysis required was established during working meetings between Argonne National Laboratory (ANL) and IAE staff during August 2006, subsequent email correspondence, and subsequent staff visits. The analysis needs to consider the current high-enriched uranium (HEU) core and 4 core configurations containing 1 and 2 LEU LTAs in various core positions. Calculations have been performed at ANL in support of the LTA irradiation. These calculations are summarized in this report and include criticality, burn-up, neutronics parameters, steady-state thermal hydraulics, and postulated transients. These calculations have been performed at the request of the IAE staff, who are performing similar calculations to be used in their SAR amendment submittal to the PAA. The ANL analysis has been performed independently from that being performed by IAE and should only be used as one step in the verification process.

  3. Dual-action Hybrid Compounds - A New Dawn in the Discovery of Multi-target Drugs: Lead Generation Approaches.

    Science.gov (United States)

    Abdolmalekia, Azizeh; Ghasemi, Jahan B

    2016-09-27

    Finding high quality beginning compounds is a critical job at the start of the lead generation stage for multi-target drug discovery (MTDD). Designing hybrid compounds as a selective multi-target chemical entity is a challenge, opportunity, and new idea to better act against specific multiple targets. One hybrid molecule is formed by two (or more) pharmacophore group's participation. So, these new compounds often exhibit two or more activities going about as multi-target drugs (mt-drugs) and may have superior safety or efficacy. Application of integrating a range of information and sophisticated new in silico, bioinformatics, structural biology, pharmacogenomics methods may be useful to discover/design, and synthesis of the new hybrid molecules. In this regard, many rational and screening approaches have followed by medicinal chemists for the lead generation in MTDD. Here, we review some popular lead generation approaches that have been used for designing multiple ligands (DMLs). This paper focuses on dual- acting chemical entities that incorporate a part of two drugs or bioactive compounds to compose hybrid molecules. Also, it presents some of key concepts and limitations/strengths of lead generation methods by comparing combination framework method with screening approaches. Besides, a number of examples to represent applications of hybrid molecules in the drug discovery are included.

  4. Cooperative effect of roscovitine and irradiation targets angiogenesis and induces vascular destabilization in human breast carcinoma.

    Science.gov (United States)

    Maggiorella, L; Aubel, C; Haton, C; Milliat, F; Connault, E; Opolon, P; Deutsch, E; Bourhis, J

    2009-02-01

    Angiogenesis is considered as an essential process for tumour development and invasion. Previously, we demonstrated that cyclin-dependent kinase inhibition by roscovitine induces a radiosensitization and a synergistic antitumoral effect in human carcinoma but its effect on the microenvironment and tumour angiogenesis remains unknown. Here, we investigated the effect of the combination roscovitine and ionizing radiation (IR) on normal cells in vitro and on tumour angiogenesis in MDA-MB 231 tumour xenografts. We observed that the combination roscovitine and IR induced a marked reduction of angiogenic hot spot and microvascular density in comparison with IR or roscovitine treatments alone. The Ang-2/Tie-2 ratio was increased in presence of reduced vascular endothelial growth factor level suggesting vessel destabilization. In vitro, no radiosensitization effect of roscovitine was found in endothelial, fibroblast, and keratinocyte cells. IR potentiated the antiproliferative effect of roscovitine without inducing apoptosis in endothelial cells. Roscovitine decreased IR-stimulated vascular endothelial growth factor secretion of MDA-MB 231 and endothelial cells. A reduction in the endothelial cells invasion and the capillary-like tube formation in Matrigel were observed following the combination roscovitine and IR. This combined treatment targets angiogenesis resulting in microvessel destabilization without inducing normal cell toxicity.

  5. Improved targeting of JAK2 leads to increased therapeutic efficacy in myeloproliferative neoplasms

    OpenAIRE

    2014-01-01

    Genetic deletion of JAK2 in vivo shows that MPN cells remain fully dependent on JAK2 signaling for survival.Dual JAK2 targeting with JAK and HSP90 inhibitors offers increased efficacy in murine models and primary samples.

  6. Experimental and theoretical study of the yields of residual product nuclei produced in thin targets irradiated by 100-2600 MeV protons

    CERN Document Server

    Titarenko, Y E; Karpikhin, E I

    2003-01-01

    The objective of the project is measurements and computer simulations of independent and cumulative yields of residual product nuclei in thin targets relevant as target materials and structure materials for hybrid accelerator-driven systems coupled to high-energy proton accelerators. The yields of residual product nuclei are of great importance when estimating such basic radiation-technology characteristics of hybrid facility targets as the total target activity, target 'poisoning', buildup of long-lived nuclides that, in turn, are to be transmuted, product nuclide (Po) alpha-activity, content of low-pressure evaporated nuclides (Hg), content of chemically-active nuclides that spoil drastically the corrosion resistance of the facility structure materials, etc. In view of the above, radioactive product nuclide yields from targets and structure materials were determined by an experiment using the ITEP U-10 proton accelerator in 51 irradiation runs for different thin targets: sup 1 sup 8 sup 2 sup , sup 1 sup 8 ...

  7. Genomes2Drugs: identifies target proteins and lead drugs from proteome data.

    LENUS (Irish Health Repository)

    Toomey, David

    2009-01-01

    BACKGROUND: Genome sequencing and bioinformatics have provided the full hypothetical proteome of many pathogenic organisms. Advances in microarray and mass spectrometry have also yielded large output datasets of possible target proteins\\/genes. However, the challenge remains to identify new targets for drug discovery from this wealth of information. Further analysis includes bioinformatics and\\/or molecular biology tools to validate the findings. This is time consuming and expensive, and could fail to yield novel drugs if protein purification and crystallography is impossible. To pre-empt this, a researcher may want to rapidly filter the output datasets for proteins that show good homology to proteins that have already been structurally characterised or proteins that are already targets for known drugs. Critically, those researchers developing novel antibiotics need to select out the proteins that show close homology to any human proteins, as future inhibitors are likely to cross-react with the host protein, causing off-target toxicity effects later in clinical trials. METHODOLOGY\\/PRINCIPAL FINDINGS: To solve many of these issues, we have developed a free online resource called Genomes2Drugs which ranks sequences to identify proteins that are (i) homologous to previously crystallized proteins or (ii) targets of known drugs, but are (iii) not homologous to human proteins. When tested using the Plasmodium falciparum malarial genome the program correctly enriched the ranked list of proteins with known drug target proteins. CONCLUSIONS\\/SIGNIFICANCE: Genomes2Drugs rapidly identifies proteins that are likely to succeed in drug discovery pipelines. This free online resource helps in the identification of potential drug targets. Importantly, the program further highlights proteins that are likely to be inhibited by FDA-approved drugs. These drugs can then be rapidly moved into Phase IV clinical studies under \\'change-of-application\\' patents.

  8. Genomes2Drugs: identifies target proteins and lead drugs from proteome data.

    Directory of Open Access Journals (Sweden)

    David Toomey

    Full Text Available BACKGROUND: Genome sequencing and bioinformatics have provided the full hypothetical proteome of many pathogenic organisms. Advances in microarray and mass spectrometry have also yielded large output datasets of possible target proteins/genes. However, the challenge remains to identify new targets for drug discovery from this wealth of information. Further analysis includes bioinformatics and/or molecular biology tools to validate the findings. This is time consuming and expensive, and could fail to yield novel drugs if protein purification and crystallography is impossible. To pre-empt this, a researcher may want to rapidly filter the output datasets for proteins that show good homology to proteins that have already been structurally characterised or proteins that are already targets for known drugs. Critically, those researchers developing novel antibiotics need to select out the proteins that show close homology to any human proteins, as future inhibitors are likely to cross-react with the host protein, causing off-target toxicity effects later in clinical trials. METHODOLOGY/PRINCIPAL FINDINGS: To solve many of these issues, we have developed a free online resource called Genomes2Drugs which ranks sequences to identify proteins that are (i homologous to previously crystallized proteins or (ii targets of known drugs, but are (iii not homologous to human proteins. When tested using the Plasmodium falciparum malarial genome the program correctly enriched the ranked list of proteins with known drug target proteins. CONCLUSIONS/SIGNIFICANCE: Genomes2Drugs rapidly identifies proteins that are likely to succeed in drug discovery pipelines. This free online resource helps in the identification of potential drug targets. Importantly, the program further highlights proteins that are likely to be inhibited by FDA-approved drugs. These drugs can then be rapidly moved into Phase IV clinical studies under 'change-of-application' patents.

  9. Quantitative resistance can lead to evolutionary changes in traits not targeted by the resistance QTLs.

    OpenAIRE

    van den Berg, F.; Lannou, C.; Gilligan, CA; Bosch, F.

    2014-01-01

    This paper addresses the general concern in plant pathology that the introduction of quantitative resistance in the landscape can lead to increased pathogenicity. Hereto, we study the hypothetical case of a quantitative trait loci (QTL) acting on pathogen spore production per unit lesion area. To regain its original fitness, the pathogen can break the QTL, restoring its spore production capacity leading to an increased spore production per lesion. Or alternatively, it can increase its lesion ...

  10. Mapping patterns of nodal metastases in esophageal carcinoma: rethinking the clinical target volume for supraclavicular nodal irradiation

    Science.gov (United States)

    Luo, Yijun; Liu, Yuhui; Wang, Xiaoli; Zhang, Bin; Yu, Jinming; Wang, Chengang; Huang, Yong

    2016-01-01

    Background To map detail distribution of metastatic supraclavicular (SCV) lymph nodes (LN) in esophageal cancer (EC) patients and determine the precise radiation therapy clinical target volume (CTV). Methods A total of 101 thoracic esophageal carcinoma patients after surgery experienced SCV LN metastasis were retrospectively examined. The SCV region is further divided into four subgroups. Using hand drawings registration, nodes were mapped to a template computed tomogram to provide a visual impression of nodal frequencies and anatomic distribution. Results In all, 158 nodes were considered to be clinical metastatic in the SCV region in the 101 patients, 74 on the left and 84 on the right. Seven of 158 (4.4%) positive LN were located in group I, 78 of 158 (49.37%) were located in group II, 72 of 158 nodes (45.6%) were located in group III, 1 of 158 (0.63%) located in group IV. Conclusions According to our results, the SCV group II and group III are considered to be the high risk regions of esophageal squamous cell carcinoma (ESCC) LN metastasis, which were defined as elective nodal irradiation (ENI) areas. PMID:28066592

  11. Study of neutron spectra in a water bath from a Pb target irradiated by 250 MeV protons

    Science.gov (United States)

    Li, Yan-Yan; Zhang, Xue-Ying; Ju, Yong-Qin; Ma, Fei; Zhang, Hong-Bin; Chen, Liang; Ge, Hong-Lin; Wan, Bo; Luo, Peng; Zhou, Bin; Zhang, Yan-Bin; Li, Jian-Yang; Xu, Jun-Kui; Wang, Song-Lin; Yang, Yong-Wei; Yang, Lei

    2015-04-01

    Spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with a cadmium (Cd) cover. According to the measured activities of the foils, the neutron flux at different resonance energies were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code. The comparison showed that the simulation could give a good prediction for the neutron spectra above 50 eV, while the finite thickness of the foils greatly effected the experimental data in low energy. It was also found that the resonance detectors themselves had great impact on the simulated energy spectra. Supported by National Natural Science Foundation and Strategic Priority Research Program of the Chinese Academy of Sciences (11305229, 11105186, 91226107, 91026009, XDA03030300)

  12. Coupling of morphology to surface transport in ion-beam-irradiated surfaces: normal incidence and rotating targets

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Garcia, Javier [Grupo Interdisciplinar de Sistemas Complejos (GISC) and School of Mathematical Sciences and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4 (Ireland); Cuerno, Rodolfo [Departamento de Matematicas and GISC, Universidad Carlos III de Madrid, Avenida de la Universidad 30, E-28911 Leganes (Spain); Castro, Mario [GISC and Grupo de Dinamica No Lineal (DNL), Escuela Tecnica Superior de IngenierIa (ICAI), Universidad Pontificia Comillas de Madrid, E-28015 Madrid (Spain)], E-mail: javiermunozgarcia@gmail.com, E-mail: cuerno@math.uc3m.es, E-mail: mariocastro73@gmail.com

    2009-06-03

    Continuum models have proved their applicability to describe nanopatterns produced by ion-beam sputtering of amorphous or amorphizable targets at low and medium energies. Here we pursue the recently introduced 'hydrodynamic approach' in the cases of bombardment at normal incidence, or of oblique incidence onto rotating targets, known to lead to self-organized arrangements of nanodots. Our approach stresses the dynamical roles of material (defect) transport at the target surface and of local redeposition. By applying results previously derived for arbitrary angles of incidence, we derive effective evolution equations for these geometries of incidence, which are then numerically studied. Moreover, we show that within our model these equations are identical (albeit with different coefficients) in both cases, provided surface tension is isotropic in the target. We thus account for the common dynamics for both types of incidence conditions, namely formation of dots with short-range order and long-wavelength disorder, and an intermediate coarsening of dot features that improves the local order of the patterns. We provide for the first time approximate analytical predictions for the dependence of stationary dot features (amplitude and wavelength) on phenomenological parameters, that improve upon previous linear estimates. Finally, our theoretical results are discussed in terms of experimental data.

  13. Differential Regulation of Ferritin Subunits and Iron Transport Proteins: An Effect of Targeted Hepatic X-Irradiation

    Directory of Open Access Journals (Sweden)

    Naila Naz

    2013-01-01

    Full Text Available The current study aimed to investigate radiation-induced regulation of iron proteins including ferritin subunits in rats. Rat livers were selectively irradiated in vivo at 25 Gy. This dose can be used to model radiation effects to the liver without inducing overt radiation-induced liver disease. Sham-irradiated rats served as controls. Isolated hepatocytes were irradiated at 8 Gy. Ferritin light polypeptide (FTL was detectable in the serum of sham-irradiated rats with an increase after irradiation. Liver irradiation increased hepatic protein expression of both ferritin subunits. A rather early increase (3 h was observed for hepatic TfR1 and Fpn-1 followed by a decrease at 12 h. The increase in TfR2 persisted over the observed time. Parallel to the elevation of AST levels, a significant increase (24 h in hepatic iron content was measured. Complete blood count analysis showed a significant decrease in leukocyte number with an early increase in neutrophil granulocytes and a decrease in lymphocytes. In vitro, a significant increase in ferritin subunits at mRNA level was detected after irradiation which was further induced with a combination treatment of irradiation and acute phase cytokine. Irradiation can directly alter the expression of ferritin subunits and this response can be strongly influenced by radiation-induced proinflammatory cytokines. FTL can be used as a serum marker for early phase radiation-induced liver damage.

  14. Ultra high frequency-electromagnetic field irradiation during pregnancy leads to an increase in erythrocytes micronuclei incidence in rat offspring.

    Science.gov (United States)

    Ferreira, Amâncio Romanelli; Knakievicz, Tanise; Pasquali, Matheus Augusto de Bittencourt; Gelain, Daniel Pens; Dal-Pizzol, Felipe; Fernández, Claudio Enrique Rodriguez; de Salles, Alvaro Augusto de Almeida; Ferreira, Henrique Bunselmeyer; Moreira, José Cláudio Fonseca

    2006-12-03

    Mobile telephones and their base stations are an important ultra high frequency-electromagnetic field (UHF-EMF) source and their utilization is increasing all over the world. Epidemiological studies suggested that low energy UHF-EMF emitted from a cellular telephone may cause biological effects, such as DNA damage and changes on oxidative metabolism. An in vivo mammalian cytogenetic test, the micronucleus (MN) assay, was used to investigate the occurrence of chromosomal damage in erythrocytes from rat offspring exposed to a non-thermal UHF-EMF from a cellular phone during their embryogenesis; the irradiated group showed a significant increase in MN occurrence. In order to investigate if UHF-EMF could also alter oxidative parameters in the peripheral blood and in the liver - an important hematopoietic tissue in rat embryos and newborns - we also measured the activity of antioxidant enzymes, quantified total sulfhydryl content, protein carbonyl groups, thiobarbituric acid-reactive species and total non-enzymatic antioxidant defense. No significant differences were found in any oxidative parameter of offspring blood and liver. The average number of pups in each litter has also not been significantly altered. Our results suggest that, under our experimental conditions, UHF-EMF is able to induce a genotoxic response in hematopoietic tissue during the embryogenesis through an unknown mechanism.

  15. How genetic testing can lead to targeted management of XIAP deficiency-related inflammatory bowel disease

    DEFF Research Database (Denmark)

    Nielsen, Ole Haagen; LaCasse, Eric Charles

    2017-01-01

    X-linked lymphoproliferative disease type 2 (XLP-2, OMIM 300635) is a primary immunodeficiency caused by the loss of X chromosome-linked inhibitor of apoptosis (XIAP), the X-linked inhibitor of apoptosis gene at Xq25. XLP-2 individuals are susceptible to several specific and potentially fatal inf......, and expedite specific targeted therapy.Genet Med advance online publication 14 July 2016Genetics in Medicine (2016); doi:10.1038/gim.2016.82....

  16. Evaluating the 1996 EU food aid reform: Did it really lead to better targeting?

    OpenAIRE

    2009-01-01

    The paper analyses the 1996 EU food aid reform and addresses the question of its impact on improving EU food aid allocation in terms of reaching those countries which are most vulnerable to food insecurity. Using a two-stage regression model the analysis finds that EU food aid in kind is increasingly targeted towards developing countries affected by food insecurity. Most importantly, characteristics such as low calorie supply and balance-of-payments difficulties gained in importance in EU foo...

  17. Current therapeutic leads for the treatment of melanoma: targeted immunotherapy in the post-genomic era.

    Science.gov (United States)

    Papanastasiou, Anastasios D; Sirinian, Chaido; Kalofonos, Haralabos P; Repanti, Maria

    2014-01-01

    Metastatic melanoma has a poor prognosis and until today most therapeutic approaches are ineffective. Advances in molecular pathology and genome analysis technologies have led to the identification of genetic events and immune regulatory checkpoints that provide novel targets for pharmaceutical intervention in melanoma. Development of selective mitogen-activated kinase (MAPK) pathway inhibitors was the first major achievement coming from genetic studies that identified a constitutively active MAP kinase pathway and BRAF activating mutations in melanoma. At the same time, the manipulation of immune system checkpoints through monoclonal antibodies changed clinical practice and led to further improvement of patient outcomes. In an effort to further develop melanoma targeted therapies that depend on the genetic profile of a given patient, high-throughput genome wide approaches (next-generation sequencing [NGS], gene arrays, etc) have been employed for the characterization of genetic alterations in the patient's tumor. In the near future, the combined information from the genetic and immune background of an individual will provide the basis for a personalized, highly targeted approach in the treatment of melanoma.

  18. Dual-targeting anti-angiogenic cyclic peptides as potential drug leads for cancer therapy

    Science.gov (United States)

    Chan, Lai Yue; Craik, David J.; Daly, Norelle L.

    2016-01-01

    Peptide analogues derived from bioactive hormones such as somatostatin or certain growth factors have great potential as angiogenesis inhibitors for cancer applications. In an attempt to combat emerging drug resistance many FDA-approved anti-angiogenesis therapies are co-administered with cytotoxic drugs as a combination therapy to target multiple signaling pathways of cancers. However, cancer therapies often encounter limiting factors such as high toxicities and side effects. Here, we combined two anti-angiogenic epitopes that act on different pathways of angiogenesis into a single non-toxic cyclic peptide framework, namely MCoTI-II (Momordica cochinchinensis trypsin inhibitor-II), and subsequently assessed the anti-angiogenic activity of the novel compound. We hypothesized that the combination of these two epitopes would elicit a synergistic effect by targeting different angiogenesis pathways and result in improved potency, compared to that of a single epitope. This novel approach has resulted in the development of a potent, non-toxic, stable and cyclic analogue with nanomolar potency inhibition in in vitro endothelial cell migration and in vivo chorioallantoic membrane angiogenesis assays. This is the first report to use the MCoTI-II framework to develop a 2-in-1 anti-angiogenic peptide, which has the potential to be used as a form of combination therapy for targeting a wide range of cancers. PMID:27734947

  19. Dual-targeting anti-angiogenic cyclic peptides as potential drug leads for cancer therapy.

    Science.gov (United States)

    Chan, Lai Yue; Craik, David J; Daly, Norelle L

    2016-10-13

    Peptide analogues derived from bioactive hormones such as somatostatin or certain growth factors have great potential as angiogenesis inhibitors for cancer applications. In an attempt to combat emerging drug resistance many FDA-approved anti-angiogenesis therapies are co-administered with cytotoxic drugs as a combination therapy to target multiple signaling pathways of cancers. However, cancer therapies often encounter limiting factors such as high toxicities and side effects. Here, we combined two anti-angiogenic epitopes that act on different pathways of angiogenesis into a single non-toxic cyclic peptide framework, namely MCoTI-II (Momordica cochinchinensis trypsin inhibitor-II), and subsequently assessed the anti-angiogenic activity of the novel compound. We hypothesized that the combination of these two epitopes would elicit a synergistic effect by targeting different angiogenesis pathways and result in improved potency, compared to that of a single epitope. This novel approach has resulted in the development of a potent, non-toxic, stable and cyclic analogue with nanomolar potency inhibition in in vitro endothelial cell migration and in vivo chorioallantoic membrane angiogenesis assays. This is the first report to use the MCoTI-II framework to develop a 2-in-1 anti-angiogenic peptide, which has the potential to be used as a form of combination therapy for targeting a wide range of cancers.

  20. Molecular desorption of stainless steel vacuum chambers irradiated with 4.2  MeV/u lead ions

    Directory of Open Access Journals (Sweden)

    E. Mahner

    2003-01-01

    Full Text Available In preparation for the heavy ion program of the Large Hadron Collider at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring. These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2  MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow discharges, nonevaporable getter coating are reported in terms of the molecular desorption yields for H_{2}, CH_{4}, CO, Ar, and CO_{2}. Unexpected large values of molecular yields per incident ion up to 2×10^{4} molecules/ion have been observed. The reduction of the ion-induced desorption yield due to continuous bombardment with lead ions (beam cleaning has been investigated for five different stainless steel vacuum chambers. The implications of these results for the vacuum system of the future Low Energy Ion Ring and possible remedies to reduce the vacuum degradation are discussed.

  1. Non-targeted transcriptomic effects upon thyroid irradiation: similarity between in-field and out-of-field responses varies with tissue type.

    Science.gov (United States)

    Langen, Britta; Rudqvist, Nils; Spetz, Johan; Swanpalmer, John; Helou, Khalil; Forssell-Aronsson, Eva

    2016-10-25

    Non-targeted effects can induce responses in tissues that have not been exposed to ionizing radiation. Despite their relevance for risk assessment, few studies have investigated these effects in vivo. In particular, these effects have not been studied in context with thyroid exposure, which can occur e.g. during irradiation of head and neck tumors. To determine the similarity between in-field and out-of-field responses in normal tissue, we used a partial body irradiation setup with female mice where the thyroid region, the thorax and abdomen, or all three regions were irradiated. After 24 h, transcriptional regulation in the kidney cortex, kidney medulla, liver, lungs, spleen, and thyroid was analyzed using microarray technology. Thyroid irradiation resulted in transcriptional regulation in the kidney medulla and liver that resembled regulation upon direct exposure of these tissues regarding both strength of response and associated biological function. The kidney cortex showed fewer similarities between the setups, while the lungs and spleen showed little similarity between in-field and out-of-field responses. Interestingly, effects were generally not found to be additive. Future studies are needed to identify the molecular mechanisms that mediate these systemic effects, so that they may be used as targets to minimize detrimental side effects in radiotherapy.

  2. Peripheral Attentional Targets under Covert Attention Lead to Paradoxically Enhanced Alpha Desynchronization in Neurofibromatosis Type 1.

    Science.gov (United States)

    Silva, Gilberto; Ribeiro, Maria J; Costa, Gabriel N; Violante, Inês; Ramos, Fabiana; Saraiva, Jorge; Castelo-Branco, Miguel

    2016-01-01

    The limited capacity of the human brain to process the full extent of visual information reaching the visual cortex requires the recruitment of mechanisms of information selection through attention. Neurofibromatosis type-1 (NF1) is a neurodevelopmental disease often exhibiting attentional deficits and learning disabilities, and is considered to model similar impairments common in other neurodevelopmental disorders such as autism. In a previous study, we found that patients with NF1 are more prone to miss targets under overt attention conditions. This finding was interpreted as a result of increased occipito-parietal alpha oscillations. In the present study, we used electroencephalography (EEG) to study alpha power modulations and the performance of patients with NF1 in a covert attention task. Covert attention was required in order to perceive changes (target offset) of a peripherally presented stimulus. Interestingly, alpha oscillations were found to undergo greater desynchronization under this task in the NF1 group compared with control subjects. A similar pattern of desynchronization was found for beta frequencies while no changes in gamma oscillations could be identified. These results are consistent with the notion that different attentional states and task demands generate different patterns of abnormal modulation of alpha oscillatory processes in NF1. Under covert attention conditions and while target offset was reported with relatively high accuracy (over 90% correct responses), excessive desynchronization was found. These findings suggest an abnormal modulation of oscillatory activity and attentional processes in NF1. Given the known role of alpha in modulating attention, we suggest that alpha patterns can show both abnormal increases and decreases that are task and performance dependent, in a way that enhanced alpha desynchronization may reflect a compensatory mechanism to keep performance at normal levels. These results suggest that dysregulation of

  3. Peripheral Attentional Targets under Covert Attention Lead to Paradoxically Enhanced Alpha Desynchronization in Neurofibromatosis Type 1.

    Directory of Open Access Journals (Sweden)

    Gilberto Silva

    Full Text Available The limited capacity of the human brain to process the full extent of visual information reaching the visual cortex requires the recruitment of mechanisms of information selection through attention. Neurofibromatosis type-1 (NF1 is a neurodevelopmental disease often exhibiting attentional deficits and learning disabilities, and is considered to model similar impairments common in other neurodevelopmental disorders such as autism. In a previous study, we found that patients with NF1 are more prone to miss targets under overt attention conditions. This finding was interpreted as a result of increased occipito-parietal alpha oscillations. In the present study, we used electroencephalography (EEG to study alpha power modulations and the performance of patients with NF1 in a covert attention task. Covert attention was required in order to perceive changes (target offset of a peripherally presented stimulus. Interestingly, alpha oscillations were found to undergo greater desynchronization under this task in the NF1 group compared with control subjects. A similar pattern of desynchronization was found for beta frequencies while no changes in gamma oscillations could be identified. These results are consistent with the notion that different attentional states and task demands generate different patterns of abnormal modulation of alpha oscillatory processes in NF1. Under covert attention conditions and while target offset was reported with relatively high accuracy (over 90% correct responses, excessive desynchronization was found. These findings suggest an abnormal modulation of oscillatory activity and attentional processes in NF1. Given the known role of alpha in modulating attention, we suggest that alpha patterns can show both abnormal increases and decreases that are task and performance dependent, in a way that enhanced alpha desynchronization may reflect a compensatory mechanism to keep performance at normal levels. These results suggest that

  4. Targeting insulin-like growth factor 1 leads to amelioration of inflammatory demyelinating disease.

    Directory of Open Access Journals (Sweden)

    Matthew F Cusick

    Full Text Available In patients with multiple sclerosis (MS and in mice with experimental autoimmune encephalomyelitis (EAE, proliferating autoreactive T cells play an important role in the pathogenesis of the disease. Due to the importance of these myelin-specific T cells, these cells have been therapeutic targets in a variety of treatments. Previously we found that Lenaldekar (LDK, a novel small molecule, could inhibit exacerbations in a preclinical model of MS when given at the start of an EAE exacerbation. In those studies, we found that LDK could inhibit human T cell recall responses and murine myelin responses in vitro. In these new studies, we found that LDK could inhibit myelin specific T cell responses through the insulin-like growth factor-1 receptor (IGF-1R pathway. Alteration of this pathway led to marked reduction in T cell proliferation and expansion. Blocking this pathway could account for the observed decreases in clinical signs and inflammatory demyelinating disease, which was accompanied by axonal preservation. Our data indicate that IGF-1R could be a potential target for new therapies for the treatment of autoimmune diseases where autoreactive T cell expansion is a requisite for disease.

  5. Measurement of Gas and Volatile Elements Production Cross Section in a Molten Lead-Bismuth Target

    CERN Multimedia

    2002-01-01

    MEGAPIE is a project for a 1 MW liquid PbBi spallation source, to be built at the SINQ facility at the Paul Scherrer Institut, which will be an important step in the roadmap towards the demonstration of the ADS concept and high power molten metal targets in general. In the design and construction of such a challenging project it is extremely important to evaluate the amount and type of gas and volatile elements which will be produced, for a reliable and safe operation of the experiment. Both stable (H, $^{4}$He and other noble gases) and radioactive isotopes are of interest. Currently, different design options are under consideration to deal with the gas produced during operation. \\\\ For a correct estimation of the production cross sections, a measurement with a liquid PbBi target and a proton beam of energy close to the one of MEGAPIE (575 MeV) is necessary. We would like to use the ISOLDE facility, which offers the unique opportunity via its mass spectrometric analysis of the elements present in the gas pha...

  6. Improved targeting of JAK2 leads to increased therapeutic efficacy in myeloproliferative neoplasms

    Science.gov (United States)

    Bhagwat, Neha; Koppikar, Priya; Keller, Matthew; Marubayashi, Sachie; Shank, Kaitlyn; Rampal, Raajit; Qi, Jun; Kleppe, Maria; Patel, Hardik J.; Shah, Smit K.; Taldone, Tony; Bradner, James E.; Chiosis, Gabriela

    2014-01-01

    The discovery of JAK2/MPL mutations in patients with myeloproliferative neoplasms (MPN) led to clinical development of Janus kinase (JAK) inhibitors for treatment of MPN. These inhibitors improve constitutional symptoms and splenomegaly but do not significantly reduce mutant allele burden in patients. We recently showed that chronic exposure to JAK inhibitors results in inhibitor persistence via JAK2 transactivation and persistent JAK–signal transducer and activator of transcription signaling. We performed genetic and pharmacologic studies to determine whether improved JAK2 inhibition would show increased efficacy in MPN models and primary samples. Jak2 deletion in vivo led to profound reduction in disease burden not seen with JAK inhibitors, and deletion of Jak2 following chronic ruxolitinib therapy markedly reduced mutant allele burden. This demonstrates that JAK2 remains an essential target in MPN cells that survive in the setting of chronic JAK inhibition. Combination therapy with the heat shock protein 90 (HSP90) inhibitor PU-H71 and ruxolitinib reduced total and phospho-JAK2 and achieved more potent inhibition of downstream signaling than ruxolitinib monotherapy. Combination treatment improved blood counts, spleen weights, and reduced bone marrow fibrosis compared with ruxolitinib alone. These data suggest alternate approaches that increase JAK2 targeting, including combination JAK/HSP90 inhibitor therapy, are warranted in the clinical setting. PMID:24470592

  7. Left ventricular pacing lead positioning in the target vein of the coronary sinus: description of a challenging case.

    Science.gov (United States)

    Frattini, Folco; Rordorf, Roberto; Angoli, Luigi; Pentimalli, Francesco; Vicentini, Alessandro; Petracci, Barbara; Magrini, Giulia; Landolina, Maurizio

    2008-04-01

    The optimal left ventricular pacing location for cardiac resynchronization therapy should be individualized according to the site of maximal mechanical delay. However, the presence of vein stenosis or kinking in coronary sinus (CS) anatomy could hamper lead implantation in the target vessel. We describe the case of a patient with dilated cardiomyopathy and a dual-chamber pacemaker referred for upgrading to a biventricular device owing to New York Heart Association III heart failure symptoms. Tissue Doppler analysis before implantation showed that the area of maximum activation delay was located in the posterolateral region of the left ventricle. Insertion of the lead into a posterolateral vein of the CS by means of the standard over-the-wire approach was unsuccessful due to the presence of a stenosis at the ostium of the vein. Lead placement in an anterior vein of the CS was unsatisfactory owing to a poor local delay from QRS onset. After balloon vein angioplasty, the pacing lead passed through the stenotic tract at the ostium of the target vein and was successfully positioned in the posterolateral region. Three months after pacemaker implantation, echocardiography showed an important reduction in the indexes of both inter- and intraventricular asynchrony and a significant left ventricular reverse remodeling.

  8. Fragile X and autism : intertwined at the molecular level leading to targeted treatments

    OpenAIRE

    Hoem, Gry

    2012-01-01

    Fragile X syndrome (FXS) is caused by an expanded CGG repeat (>200 repeats) in the 5’ un-translated portion of the fragile mental retardation 1 gene (FMR1) leading to deficiency or absence of the FMR1 protein (FMRP). FMRP is an RNA carrier protein that controls the translation of a number of other genes that regulate synaptic development and plasticity. Autism occurs in approximately 30% of FXS cases, and Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS) occurs in an additio...

  9. UV irradiation-induced apoptosis leads to activation of a 36-kDa myelin basic protein kinase in HL-60 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lu, M.L.; Sato, Mitsuhiro; Cao, Boliang; Richie, J.P. [Harvard Medical School, Boston, MA (United States)

    1996-08-20

    UV irradiation induces apoptosis (or programmed cell death) in HL-60 promyelocytic leukemia cells within 3 h. UV-induced apoptosis is accompanied by activation of a 36-kDa myelin basic protein kinase (p36 MBP kinase). This kinase is also activated by okadaic acid and retinoic acid-induced apoptosis. Irrespective of the inducing agent, p36 MBP kinase activation is restricted to the subpopulation of cells actually undergoing apoptosis. Activation of p36 MBP kinase occurs in enucleated cytoplasts, indicating no requirements for a nucleus or fragmented DNA in signaling. We also demonstrate the activation of p36 kinase in tumor necrosis factor-{alpha}-and serum starvation-induced cell death using the human prostatic tumor cell line LNCap and NIH 3T3 fibroblasts, respectively. We postulate that p36 MBP kinase is a common component in diverse signaling pathways leading to apoptosis. 40 refs., 5 figs.

  10. Molecular desorption of stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Laurent, Jean Michel; Madsen, N

    2003-01-01

    In preparation for the heavy ion program of the Large Hadron Collider (LHC) at CERN, accumulation and cooling tests with lead ion beams have been performed in the Low Energy Antiproton Ring (LEAR). These tests have revealed that due to the unexpected large outgassing of the vacuum system, the dynamic pressure of the ring could not be maintained low enough to reach the required beam intensities. To determine the actions necessary to lower the dynamic pressure rise, an experimental program has been initiated for measuring the molecular desorption yields of stainless steel vacuum chambers by the impact of 4.2 MeV/u lead ions with the charge states +27 and +53. The test chambers were exposed either at grazing or at perpendicular incidence. Different surface treatments (glow-discharges, non-evaporable getter coating) are reported in terms of the molecular desorption yields for H2, CH4, CO, Ar and CO2. Unexpected large values of molecular yields per incident ion up to 2 104 molecules/ion have been observed. The red...

  11. Oxidative stress mediated Ca(2+) release manifests endoplasmic reticulum stress leading to unfolded protein response in UV-B irradiated human skin cells.

    Science.gov (United States)

    Farrukh, Mufti R; Nissar, Ul A; Afnan, Quadri; Rafiq, Rather A; Sharma, Love; Amin, Shajrul; Kaiser, Peerzada; Sharma, Parduman R; Tasduq, Sheikh A

    2014-07-01

    Exposure of skin to ultraviolet (UV) radiation, an environmental stressor induces number of adverse biological effects (photodamage), including cancer. The damage induced by UV-irradiation in skin cells is initiated by the photochemical generation of reactive oxygen species (ROS) and induction of endoplasmic reticulum (ER) stress and consequent activation of unfolded protein response (UPR). To decipher cellular and molecular events responsible for UV-B mediated ER stress and UPR activation in skin cells. The study was performed on human skin fibroblast (Hs68) and keratinocyte (HaCaT) cells exposed to UV-B radiations in lab conditions. Different parameters of UVB induced cellular and molecular changes were analyzed using Western-blotting, microscopic studies and flow cytometry. Our results depicted that UV-B induces an immediate ROS generation that resulted in emptying of ER Ca(2+) stores inducing ER stress and activation of PERK-peIF2α-CHOP pathway. Quenching ROS generation by anti-oxidants prevented Ca(2+) release and subsequent induction of ER stress and UPR activation. UV-B irradiation induced PERK dependent G2/M phase cell cycle arrest in Hs68 and G1/S phase cell cycle arrest in HaCaT. Also our study reflects that UV-B exposure leads to loss of mitochondrial membrane potential, activation of apoptotic cascade as evident by AnnexinV/PI staining, decreased expression of Bcl-2 and increased cleavage of PARP-1 protein. UV-B induced Ca(2+) deficit within ER lumen was mediated by immediate ROS generation. Insufficient Ca(2+) concentration within ER lumen developed ER stress leading to UPR activation. These changes were reversed by use of anti-oxidants which quench ROS. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  12. Targeting acetylcholinesterase: identification of chemical leads by high throughput screening, structure determination and molecular modeling.

    Directory of Open Access Journals (Sweden)

    Lotta Berg

    Full Text Available Acetylcholinesterase (AChE is an essential enzyme that terminates cholinergic transmission by rapid hydrolysis of the neurotransmitter acetylcholine. Compounds inhibiting this enzyme can be used (inter alia to treat cholinergic deficiencies (e.g. in Alzheimer's disease, but may also act as dangerous toxins (e.g. nerve agents such as sarin. Treatment of nerve agent poisoning involves use of antidotes, small molecules capable of reactivating AChE. We have screened a collection of organic molecules to assess their ability to inhibit the enzymatic activity of AChE, aiming to find lead compounds for further optimization leading to drugs with increased efficacy and/or decreased side effects. 124 inhibitors were discovered, with considerable chemical diversity regarding size, polarity, flexibility and charge distribution. An extensive structure determination campaign resulted in a set of crystal structures of protein-ligand complexes. Overall, the ligands have substantial interactions with the peripheral anionic site of AChE, and the majority form additional interactions with the catalytic site (CAS. Reproduction of the bioactive conformation of six of the ligands using molecular docking simulations required modification of the default parameter settings of the docking software. The results show that docking-assisted structure-based design of AChE inhibitors is challenging and requires crystallographic support to obtain reliable results, at least with currently available software. The complex formed between C5685 and Mus musculus AChE (C5685•mAChE is a representative structure for the general binding mode of the determined structures. The CAS binding part of C5685 could not be structurally determined due to a disordered electron density map and the developed docking protocol was used to predict the binding modes of this part of the molecule. We believe that chemical modifications of our discovered inhibitors, biochemical and biophysical

  13. Neonicotinoids target distinct nicotinic acetylcholine receptors and neurons, leading to differential risks to bumblebees

    Science.gov (United States)

    Moffat, Christopher; Buckland, Stephen T.; Samson, Andrew J.; McArthur, Robin; Chamosa Pino, Victor; Bollan, Karen A.; Huang, Jeffrey T.-J.; Connolly, Christopher N.

    2016-04-01

    There is growing concern over the risk to bee populations from neonicotinoid insecticides and the long-term consequences of reduced numbers of insect pollinators to essential ecosystem services and food security. Our knowledge of the risk of neonicotinoids to bees is based on studies of imidacloprid and thiamethoxam and these findings are extrapolated to clothianidin based on its higher potency at nicotinic acetylcholine receptors. This study addresses the specificity and consequences of all three neonicotinoids to determine their relative risk to bumblebees at field-relevant levels (2.5 ppb). We find compound-specific effects at all levels (individual cells, bees and whole colonies in semi-field conditions). Imidacloprid and clothianidin display distinct, overlapping, abilities to stimulate Kenyon cells, indicating the potential to differentially influence bumblebee behavior. Bee immobility was induced only by imidacloprid, and an increased vulnerability to clothianidin toxicity only occurred following chronic exposure to clothianidin or thiamethoxam. At the whole colony level, only thiamethoxam altered the sex ratio (more males present) and only clothianidin increased queen production. Finally, both imidacloprid and thiamethoxam caused deficits in colony strength, while no detrimental effects of clothianidin were observed. Given these findings, neonicotinoid risk needs to be considered independently for each compound and target species.

  14. Optimized hydrophobic interactions and hydrogen bonding at the target-ligand interface leads the pathways of drug-designing.

    Directory of Open Access Journals (Sweden)

    Rohan Patil

    Full Text Available BACKGROUND: Weak intermolecular interactions such as hydrogen bonding and hydrophobic interactions are key players in stabilizing energetically-favored ligands, in an open conformational environment of protein structures. However, it is still poorly understood how the binding parameters associated with these interactions facilitate a drug-lead to recognize a specific target and improve drugs efficacy. To understand this, comprehensive analysis of hydrophobic interactions, hydrogen bonding and binding affinity have been analyzed at the interface of c-Src and c-Abl kinases and 4-amino substituted 1H-pyrazolo [3, 4-d] pyrimidine compounds. METHODOLOGY: In-silico docking studies were performed, using Discovery Studio software modules LigandFit, CDOCKER and ZDOCK, to investigate the role of ligand binding affinity at the hydrophobic pocket of c-Src and c-Abl kinase. Hydrophobic and hydrogen bonding interactions of docked molecules were compared using LigPlot program. Furthermore, 3D-QSAR and MFA calculations were scrutinized to quantify the role of weak interactions in binding affinity and drug efficacy. CONCLUSIONS: The in-silico method has enabled us to reveal that a multi-targeted small molecule binds with low affinity to its respective targets. But its binding affinity can be altered by integrating the conformationally favored functional groups at the active site of the ligand-target interface. Docking studies of 4-amino-substituted molecules at the bioactive cascade of the c-Src and c-Abl have concluded that 3D structural folding at the protein-ligand groove is also a hallmark for molecular recognition of multi-targeted compounds and for predicting their biological activity. The results presented here demonstrate that hydrogen bonding and optimized hydrophobic interactions both stabilize the ligands at the target site, and help alter binding affinity and drug efficacy.

  15. The Pattern of Failure after Re-Irradiation of Recurrent Squamous Cell Head and Neck Cancer: Implications for Defining the Targets

    Science.gov (United States)

    Popovtzer, Aron; Gluck, Iris; Chepeha, Douglas B; Teknos, Theodoros N; Moyer, Jeffrey S; Prince, Mark E; Bradford, Carol R; Eisbruch, Avraham

    2009-01-01

    Purpose Re-irradiation (re-RT) of recurrent head and neck cancer (HNC) may achieve long term disease control in some patients, at the expense of high rates of late sequelae. Limiting the re-RT targets to the recurrent gross tumor volume (rGTV) would reduce the volumes of re-irradiated tissues, however, its effect on tumor recurrence pattern is unknown. Methods Retrospective review of 66 patients who underwent curative-intent re-RT for non-resectable recurrent or second primary mucosal squamous cell HNC. Treatment was delivered with 3-dimensional conformal (3D) RT or intensity modulated RT (IMRT). The targets in all patients consisted of the rGTVs with tight (0.5 cm) margins, with no intent to treat prophylactically lymph nodes or sub-clinical disease in the vicinity of the rGTVs. The sites of local-regional failures (LRFs) were determined using imaging at the time of failure, and were compared to the rGTVs. Results Median re-RT dose was 68 Gy. 47 patients (71%) received concomitant chemotherapy and 31 (47%) received hyperfractionated, accelerated RT. At a median follow up 42 month, 16 (23%) are alive and free of disease. Fifty patients (77%) had a third recurrence or persistent disease, including 47 LRFs. All LRFs occurred within the rGTVs except for two (4%) (95% C.I. 0; 11 %). Nineteen patients (29%) had grade ≥3 late complications, mostly dysphagia (12 patients). Conclusion Almost all LRFs occurred within the re-irradiated rGTVs despite avoiding prophylactic RT of tissue at risk of subclinical disease. These results support confining the re-RT targets to the rGTVs to reduce re-irradiated tissue volumes. PMID:19135312

  16. Spider-venom peptides that target voltage-gated sodium channels: pharmacological tools and potential therapeutic leads.

    Science.gov (United States)

    Klint, Julie K; Senff, Sebastian; Rupasinghe, Darshani B; Er, Sing Yan; Herzig, Volker; Nicholson, Graham M; King, Glenn F

    2012-09-15

    Voltage-gated sodium (Na(V)) channels play a central role in the propagation of action potentials in excitable cells in both humans and insects. Many venomous animals have therefore evolved toxins that modulate the activity of Na(V) channels in order to subdue their prey and deter predators. Spider venoms in particular are rich in Na(V) channel modulators, with one-third of all known ion channel toxins from spider venoms acting on Na(V) channels. Here we review the landscape of spider-venom peptides that have so far been described to target vertebrate or invertebrate Na(V) channels. These peptides fall into 12 distinct families based on their primary structure and cysteine scaffold. Some of these peptides have become useful pharmacological tools, while others have potential as therapeutic leads because they target specific Na(V) channel subtypes that are considered to be important analgesic targets. Spider venoms are conservatively predicted to contain more than 10 million bioactive peptides and so far only 0.01% of this diversity been characterised. Thus, it is likely that future research will reveal additional structural classes of spider-venom peptides that target Na(V) channels.

  17. Identification and Functional Analysis of MicroRNAs and Their Targets in Platanus acerifolia under Lead (Pb Stress

    Directory of Open Access Journals (Sweden)

    Yuanlong Wang

    2015-03-01

    Full Text Available MicroRNAs (miRNAs play important regulatory roles in development and stress responses in plants. Lead (Pb is a non-essential element that is highly toxic to living organisms. Platanus acerifolia is grown as a street tree in cities throughout temperate regions for its importance in improving the urban ecological environment. MiRNAs that respond to abiotic stresses have been identified in plants; however, until now, the influence of Pb stress on P. acerifolia miRNAs has not been reported. To identify miRNAs and predict their target genes under Pb stress, two small RNA and two degradome libraries were constructed from Pb-treated and Pb-free leaves of P. acerifolia seedlings. After sequencing, 55 known miRNAs and 129 novel miRNAs were obtained, and 104 target genes for the miRNAs were identified by degradome sequencing. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to predict the functions of the targets. The expressions of eight differentially expressed miRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR. This is the first report about P. acerifolia miRNAs and their target genes under Pb stress. This study has provided data for further research into molecular mechanisms involved in resistance of P. acerifolia to Pb stress.

  18. The Effect of Beam Intensity on Temperature Distribution in ADS Windowless Lead-Bismuth Eutectic Spallation Target

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2014-01-01

    Full Text Available The spallation target is the component coupling the accelerator and the reactor and is regarded as the “heart” of the accelerator driven system (ADS. Heavy liquid metal lead-bismuth eutectic (LBE is served as core coolant and spallation material to carry away heat deposition of spallation reaction and produce high flux neutron. So it is very important to study the heat transfer process in the target. In this paper, the steady-state flow pattern has been numerically obtained and taken as the input for the nuclear physics calculation, and then the distribution of the extreme large power density of the heat load is imported back to the computational fluid dynamics as the source term in the energy equation. Through the coupling, the transient and steady-state temperature distribution in the windowless spallation target is obtained and analyzed based on the flow process and heat transfer. Comparison of the temperature distribution with the different beam intensity shows that its shape is the same as broken wing of the butterfly. Nevertheless, the maximum temperature as well as the temperature gradient is different. The results play an important role and can be applied to the further design and optimization of the ADS windowless spallation target.

  19. Identification and Functional Analysis of MicroRNAs and Their Targets in Platanus acerifolia under Lead (Pb) Stress

    Science.gov (United States)

    Wang, Yuanlong; Zhao, Zhenli; Deng, Minjie; Liu, Rongning; Niu, Suyan; Fan, Guoqiang

    2015-01-01

    MicroRNAs (miRNAs) play important regulatory roles in development and stress responses in plants. Lead (Pb) is a non-essential element that is highly toxic to living organisms. Platanus acerifolia is grown as a street tree in cities throughout temperate regions for its importance in improving the urban ecological environment. MiRNAs that respond to abiotic stresses have been identified in plants; however, until now, the influence of Pb stress on P. acerifolia miRNAs has not been reported. To identify miRNAs and predict their target genes under Pb stress, two small RNA and two degradome libraries were constructed from Pb-treated and Pb-free leaves of P. acerifolia seedlings. After sequencing, 55 known miRNAs and 129 novel miRNAs were obtained, and 104 target genes for the miRNAs were identified by degradome sequencing. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to predict the functions of the targets. The expressions of eight differentially expressed miRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). This is the first report about P. acerifolia miRNAs and their target genes under Pb stress. This study has provided data for further research into molecular mechanisms involved in resistance of P. acerifolia to Pb stress. PMID:25830479

  20. Novel Approaches for Concurrent Irradiation in Locally Advanced Cervical Cancer: Platinum Combinations, Non-Platinum-Containing Regimens, and Molecular Targeted Agents

    Directory of Open Access Journals (Sweden)

    Giannis Mountzios

    2013-01-01

    Full Text Available Despite the available prevention and early detection strategies, squamous-cell carcinoma of the uterine cervix is still diagnosed as locally advanced disease in a considerable proportion of patients. As a potent sensitizer of cancer cells, cisplatin has been the “traditional partner” of external beam irradiation in this setting for more than two decades. Induction chemotherapy strategies followed by concurrent chemoradiation or surgery and preoperative concurrent chemoradiation have been recently implemented in clinical trials in an effort to optimize local control and to minimize the risk of distant metastases. In this context, cisplatin has been combined with a number of other potential radiosensitizers, including 5-fluorouracil, capecitabine, and gemcitabine. In patients resistant or intolerant to platinum compounds, numerous non-platinum-containing regimens have been developed, implementing various antimetabolites, taxanes, antineoplastic antibiotics, and topoisomerase II inhibitors. More recently, molecular agents targeting critical pathways in cervical malignant transformation are being assessed in early clinical trials in combination with external-beam irradiation. In the current work, we review the evolving role of cisplatin and other platinum compounds, either alone or in combination regimens, in the context of other potent radiosensitizers. The emerging role of molecular targeted agents, as candidate partners of external beam irradiation, is also discussed.

  1. Assembly and Irradiation Modeling of Residual Stresses in Low-Enriched Uranium Foil-Based Annular Targets for Molybdenum-99 Production

    Directory of Open Access Journals (Sweden)

    Srisharan G. Govindarajan

    2013-01-01

    Full Text Available This paper considers a composite cylindrical structure, with low-enriched uranium (LEU foil enclosed between two aluminum 6061-T6 cylinders. A recess is cut all around the outer circumference of the inner tube to accommodate the LEU foil of open-cross section. To obtain perfect contact at the interfaces of the foil and the tubes, an internal pressure is applied to the inner tube, thereby plastically and elastically deforming it. The residual stresses resulting from the assembly process are used along with a thermal stress model to predict the stress margins in the cladding during irradiation. The whole process was simulated as a steady-state two-dimensional problem using the commercial finite element code Abaqus FEA. The irradiation behavior of the annular target has been presented, and the effect of the assembly residual stresses has been discussed.

  2. Co-targeting Deoxyribonucleic Acid–Dependent Protein Kinase and Poly(Adenosine Diphosphate-Ribose) Polymerase-1 Promotes Accelerated Senescence of Irradiated Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Azad, Arun, E-mail: arun.azad@bccancer.bc.ca [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Department of Pathology, St. Vincent' s Hospital, University of Melbourne, Parkville, Victoria (Australia); Bukczynska, Patricia; Jackson, Susan [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Haput, Ygal; Cullinane, Carleen [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria (Australia); McArthur, Grant A.; Solomon, Benjamin [Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Division of Cancer Medicine, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Department of Medicine, St. Vincent' s Hospital, University of Melbourne, Parkville, Victoria (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria (Australia)

    2014-02-01

    Purpose: To examine the effects of combined blockade of DNA-dependent protein kinase (DNA-PK) and poly(adenosine diphosphate-ribose) polymerase-1 (PARP-1) on accelerated senescence in irradiated H460 and A549 non-small cell lung cancer cells. Methods and Materials: The effects of KU5788 and AG014699 (inhibitors of DNA-PK and PARP-1, respectively) on clonogenic survival, DNA double-strand breaks (DSBs), apoptosis, mitotic catastrophe, and accelerated senescence in irradiated cells were examined in vitro. For in vivo experiments, H460 xenografts established in athymic nude mice were treated with BEZ235 (a DNA-PK, ATM, and phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor) and AG014699 to determine effects on proliferation, DNA DSBs, and accelerated senescence after radiation. Results: Compared with either inhibitor alone, combination treatment with KU57788 and AG014699 reduced postradiation clonogenic survival and significantly increased persistence of Gamma-H2AX (γH2AX) foci in irradiated H460 and A549 cells. Notably, these effects coincided with the induction of accelerated senescence in irradiated cells as reflected by positive β-galactosidase staining, G2-M cell-cycle arrest, enlarged and flattened cellular morphology, increased p21 expression, and senescence-associated cytokine secretion. In irradiated H460 xenografts, concurrent therapy with BEZ235 and AG014699 resulted in sustained Gamma-H2AX (γH2AX) staining and prominent β-galactosidase activity. Conclusion: Combined DNA-PK and PARP-1 blockade increased tumor cell radiosensitivity and enhanced the prosenescent properties of ionizing radiation in vitro and in vivo. These data provide a rationale for further preclinical and clinical testing of this therapeutic combination.

  3. Experimental new automatic tools for robotic stereotactic neurosurgery: towards "no hands" procedure of leads implantation into a brain target.

    Science.gov (United States)

    Mazzone, P; Arena, P; Cantelli, L; Spampinato, G; Sposato, S; Cozzolino, S; Demarinis, P; Muscato, G

    2016-07-01

    The use of robotics in neurosurgery and, particularly, in stereotactic neurosurgery, is becoming more and more adopted because of the great advantages that it offers. Robotic manipulators easily allow to achieve great precision, reliability, and rapidity in the positioning of surgical instruments or devices in the brain. The aim of this work was to experimentally verify a fully automatic "no hands" surgical procedure. The integration of neuroimaging to data for planning the surgery, followed by application of new specific surgical tools, permitted the realization of a fully automated robotic implantation of leads in brain targets. An anthropomorphic commercial manipulator was utilized. In a preliminary phase, a software to plan surgery was developed, and the surgical tools were tested first during a simulation and then on a skull mock-up. In such a way, several tools were developed and tested, and the basis for an innovative surgical procedure arose. The final experimentation was carried out on anesthetized "large white" pigs. The determination of stereotactic parameters for the correct planning to reach the intended target was performed with the same technique currently employed in human stereotactic neurosurgery, and the robotic system revealed to be reliable and precise in reaching the target. The results of this work strengthen the possibility that a neurosurgeon may be substituted by a machine, and may represent the beginning of a new approach in the current clinical practice. Moreover, this possibility may have a great impact not only on stereotactic functional procedures but also on the entire domain of neurosurgery.

  4. Investigations on femtosecond-pulse-driven soft X-ray lasers using a gas puff target irradiated with a Ti:sapphire laser

    Energy Technology Data Exchange (ETDEWEB)

    Fiedorowicz, H.; Bartnik, A.; Szczurek, M. [Military Univ. of Technology, Warsaw (Poland). Inst. of Optoelectronics; Mocek, T.; Shin, H.J.; Cha, Y.H.; Lee, D.G.; Hong, K.H.; Nam, C.H. [Military Univ. of Technology, Warsaw (Poland). Inst. of Optoelectronics; Korea Advanced Inst. of Science and Technology, Taejon (Korea). Dept. of Physics

    2001-07-01

    Experimental investigations on soft X-ray lasers based on optical field ionization of gases with an ultrashort-pulse terawatt laser system are presented. The X-ray laser active medium was created using an elongated gas puff target formed by pulsed injection of a small amount of gas from a high-pressure electromagnetic valve through a nozzle in the form of a slit. The target was irradiated with a laser pulses from a 20-fs. 50-mJ Ti:Sapphire (Ti:S) laser system. Both recombination and collisional soft X-ray laser scheme have been studied. Soft X-ray spectra from nitrogen, oxygen, and xenon targets are presented and discussed. (orig.)

  5. Short-term uvb-irradiation leads to putative limbal stem cell damage and niche cell-mediated upregulation of macrophage recruiting cytokines

    Directory of Open Access Journals (Sweden)

    Maria Notara

    2015-11-01

    Full Text Available Ultraviolet light B (UVB-irradiation is linked to various ocular pathologies such as limbal stem cell defects in pterygium. Despite the large circumstantial evidence linking UVB irradiation and limbal epithelial stem cell damage, the precise molecular responses of limbal stem cells to UVB irradiation are unclear. Here the effect of UVB irradiation on the putative stem cell phenotype, limbal niche cells and the subsequent effects on corneal (lymphangiogenic privilege were investigated. Primary human limbal epithelial stem cells and fibroblasts were irradiated with 0.02 J/cm2 of UVB, a low dose corresponding to 3 min of solar irradiation. UVB irradiation caused significant reduction of limbal epithelial and limbal fibroblast proliferation for 24 h, but apoptosis of limbal epithelial stem cells only. Moreover, UVB induced stem-like character loss of limbal epithelial cells, as their colony forming efficiency and putative stem cell marker expression significantly decreased. Interestingly, limbal epithelial cells co-cultured with UVB-irradiated limbal fibroblasts also exhibited loss of stem cell character and decrease of colony forming efficiency. Conditioned media from limbal epithelial cells inhibited lymphatic endothelial cell proliferation and tube network complexity; however this effect diminished following UVB irradiation. In contrast, pro-inflammatory and macrophage-recruiting cytokines such as TNFα, IFNγ and MCP1 were significantly upregulated following cell irradiation of limbal fibroblasts. These data demonstrate the key role of the limbal stem cell niche in response to UVB and subsequent (lymphangiogenic and inflammatory events. These data suggest that the known pro(lymphangiogenic effect of UVB irradiation in pterygium is not linked to a direct up-regulation of pro-angiogenic cytokines, but rather to indirect macrophage-recruiting cytokines being upregulated after UVB irradiation.

  6. Using environmental public health tracking to identify community targets for public health actions in childhood lead poisoning in Wisconsin.

    Science.gov (United States)

    Berney, Dawn; Camponeschi, Jenny; Coons, Marjorie; Creswell, Paul D; Schirmer, Joe; Walsh, Reghan

    2015-01-01

    In an effort to improve the ability of local public health departments to target resources to the highest need regions, the Wisconsin Environmental Public Health Tracking (WI EPHT) Program worked to enhance its public portal to benefit the Wisconsin Childhood Lead Poisoning Prevention Program (WCLPPP) and other programs. The WI EPHT Program conducted this enhancement in collaboration with WCLPPP. The WI EPHT enhanced public portal is the next phase of Wisconsin's ongoing efforts in environmental public health tracking. As part of this process, this new mapping application includes mapping capacity that provides information on childhood lead testing and results at county and census tract levels in Wisconsin. The WI EPHT Program will update its public portal to have the capability to map data at a subcounty level (ie, census tract or zip code) for some data topics when such data are available. This tool is available to local public health departments and other public health organizations throughout Wisconsin as a resource to identify communities most affected by the Centers for Disease Control and Prevention's new guidelines with regard to childhood lead poisoning. The collaboration between WI EPHT and WCLPPP on updating and enhancing the portal exemplifies the power of environmental health data to inform a more accurate understanding of public health problems.

  7. Study of 232Th(n, γ) and 232Th(n,f) reaction rates in a graphite moderated spallation neutron field produced by 1.6 GeV deuterons on lead target

    Science.gov (United States)

    Asquith, N. L.; Hashemi-Nezhad, S. R.; Westmeier, W.; Zhuk, I.; Tyutyunnikov, S.; Adam, J.

    2015-02-01

    The Gamma-3 assembly of the Joint Institute for Nuclear Research (JINR), Dubna, Russia is designed to emulate the neutron spectrum of a thermal Accelerator Driven System (ADS). It consists of a lead spallation target surrounded by reactor grade graphite. The target was irradiated with 1.6 GeV deuterons from the Nuclotron accelerator and the neutron capture and fission rate of 232Th in several locations within the assembly were experimentally measured. 232Th is a proposed fuel for envisaged Accelerator Driven Systems and these two reactions are fundamental to the performance and feasibility of 232Th in an ADS. The irradiation of the Gamma-3 assembly was also simulated using MCNPX 2.7 with the INCL4 intra-nuclear cascade and ABLA fission/evaporation models. Good agreement between the experimentally measured and calculated reaction rates was found. This serves as a good validation for the computational models and cross section data used to simulate neutron production and transport of spallation neutrons within a thermal ADS.

  8. INTERACTION OF LASER RADIATION WITH MATTER AND OTHER LASER APPLICATIONS: Changes in the emission properties of metal targets during pulse-periodic laser irradiation

    Science.gov (United States)

    Konov, Vitalii I.; Pimenov, S. M.; Prokhorov, A. M.; Chapliev, N. I.

    1988-02-01

    A scanning electron microscope was used with a pulse-periodic CO2 laser to discover the laws governing the correlation of the modified microrelief of metal surfaces, subjected to the action of multiple laser pulses, with the emission of charged particles and the luminescence of the irradiated zone. It was established that the influence of sorption and laser-induced desorption on the emission signals may be manifested differently depending on the regime of current generation in the "target-vacuum chamber" circuit.

  9. Comparison of the (p,xn) cross sections from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured absolute cross sections for (p,xn) reactions (x ranges from 0 to 8) from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons at the Brookhaven AGS Linac injector. Chemical yields were determined by using /sup 239/Np and /sup 233/Pa as tracers. Yield patterns obtained in this work can be compared to the experimental results and theoretical calculations from earlier work, and they are consistent within the framework of intranuclear cascade followed by neutron evaporation and fission competition.

  10. The technology of indirectly irradiated targets for inertial fusion researches at the Russian Federal nuclear center - VNIIEF

    Energy Technology Data Exchange (ETDEWEB)

    Andramanova, Y.V.; Veselov, A.V.; Zhidkov, N.V.; Ivanin, I.A.; Ignatev, Y.V.; Izgorodin, V.M.; Kirillov, G.A.; Komleva, G.A.; Makarov, M.Y.; Medvedev, E.F.; Morovov, A.P.; Nikolaev, G.P.; Pinegin, A.V.; Romaev, V.N.; Solomatina, E.Y.; Tacenko, M.V.; Tenyaev, B.N.; Cherkesova, I.N.; Yukhimchuk, A.A. [Russian Federal Nuclear Center, All-Russian Scientific Research Institute of Experimental Physics, RFNC-VNIIEF, Sarov (Russian Federation)

    2000-07-01

    The results of targets technology development for indirectly drive implosion experiments on the laser facility ISKRA-5, and also the constructions of targets developed at VNIIEF during last 4 years are represented. Moreover, a development of not destroying control methods for target parameters is written. (authors)

  11. Project and implantation of automation in irradiation systems for solid, liquid and gaseous targets in cyclotrons aiming the production of radioisotopes

    CERN Document Server

    Araujo, S G D

    2001-01-01

    Nowadays, two cyclotron are being operated at IPEN-CNEN/SP: one model CV-28, capable of accelerating p, d sup 3 He sub 4 and alpha, with energies of 24, 14, 36 and 28 MeV, respectively, and beam currents up to 30 mu A; the other one, model Cyclone 30, accelerates protons with energy of 30 MeV and currents up to 350 mu A. Both have the objective of irradiating targets both for radioisotopes production for use in nuclear medicine, such as sup 6 sup 7 Ga, sup 2 sup 0 sup 1 Tl, sup 1 sup 2 sup 3 I, sup 1 sup 8 F and general research. The development of irradiating systems completely automatic was the objective of this work, always aiming to reduce the radiation exposition dose to the workers and to increase the reliability of use of these systems, because very high activities are expected in these processes. In the automation, a Programmable Logical Controller (PCL) was used connected to a feedback net, to manage all the variables involved in the irradiation processes. The program of the PCL was developed using S...

  12. Methods for chemical recovery of non-carrier-added radioactive tin from irradiated intermetallic Ti-Sb targets

    Science.gov (United States)

    Lapshina, Elena V [Troitsk, RU; Zhuikov, Boris L [Troitsk, RU; Srivastava, Suresh C [Setauket, NY; Ermolaev, Stanislav V [Obninsk, RU; Togaeva, Natalia R [Obninsk, RU

    2012-01-17

    The invention provides a method of chemical recovery of no-carrier-added radioactive tin (NCA radiotin) from intermetallide TiSb irradiated with accelerated charged particles. An irradiated sample of TiSb can be dissolved in acidic solutions. Antimony can be removed from the solution by extraction with dibutyl ether. Titanium in the form of peroxide can be separated from tin using chromatography on strong anion-exchange resin. In another embodiment NCA radiotin can be separated from iodide solution containing titanium by extraction with benzene, toluene or chloroform. NCA radiotin can be finally purified from the remaining antimony and other impurities using chromatography on silica gel. NCA tin-117m can be obtained from this process. NCA tin-117m can be used for labeling organic compounds and biological objects to be applied in medicine for imaging and therapy of various diseases.

  13. Century-Long Monitoring of Solar Irradiance and Earth's Albedo Using a Stable Scattering Target in Space

    CERN Document Server

    Judge, Philip G

    2015-01-01

    An inert sphere of a few meters diameter, placed in a special stable geosynchronous orbit in perpetuo, can be used for a variety of scientific experiments. Ground-based observations of such a sphere, "GeoSphere", can resolve very difficult problems in measuring the long-term solar irradiance. GeoSphere measurements will also help us understand the evolution of Earth's albedo and climate over at least the next century.

  14. High-brightness laser plasma soft X-ray source using a double-stream gas puff target irradiated with the Prague Asterix Laser System (PALS)

    Energy Technology Data Exchange (ETDEWEB)

    Fiedorowicz, H.; Bartnik, A.; Juha, L.; Jungwirth, K.; Kralikova, B.; Krasa, J.; Kubat, P.; Pfeifer, M.; Pina, L.; Prchal, P.; Rohlena, K.; Skala, J.; Ullschmied, J.; Horvath, M.; Wawer, J

    2004-01-14

    High brightness laser plasma soft X-ray source based on a recently developed double-stream gas puff target irradiated with 0.5 ns laser pulses with energies up to 700 J from the Prague Asterix Laser System (PALS) is presented. The gas puff target was created by pulsed injection of xenon into a hollow stream of helium using an electromagnetic valve system with the double-nozzle setup. Soft X-ray emission was measured using the transmission grating spectrograph coupled to a CCD camera and the calibrated silicon photodiodes. The absolute soft X-ray production was determined to be 160 J for 540 J of laser energy, giving the soft X-ray conversion efficiency of about 30%. The source has been used in initial experiments on soft X-ray ablation of organic polymers and elemental solids.

  15. Performance evaluation and post-irradiation examination of a novel LWR fuel composed of U0.17ZrH1.6 fuel pellets bonded to Zircaloy-2 cladding by lead bismuth eutectic

    Science.gov (United States)

    Balooch, Mehdi; Olander, Donald R.; Terrani, Kurt A.; Hosemann, Peter; Casella, Andrew M.; Senor, David J.; Buck, Edgar C.

    2017-04-01

    A novel light water reactor fuel has been designed and fabricated at the University of California, Berkeley; irradiated at the Massachusetts Institute of Technology Reactor; and examined within the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory. This fuel consists of U0.17ZrH1.6 fuel pellets core-drilled from TRIGA reactor fuel elements that are clad in Zircaloy-2 and bonded with lead-bismuth eutectic. The performance evaluation and post irradiation examination of this fuel are presented here.

  16. Measurement of carbon deposit at to irradiate a target; Medicion del deposito de carbon al irradiar un blanco

    Energy Technology Data Exchange (ETDEWEB)

    Rosales M, P.; Aguilera R, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    Backscattering data obtained when bombarding a thin target of {sup 12} C deposited on a thick substrate of Ta are analyzed, with a ion beam of {sup 12} C for high fluences and different energy between 9.85 and 13 MeV. A variation in the thickness of the target is observed and is found its correlation with the fluence in the target. (Author)

  17. An analytic solution for calculating the beam intensity profiles useful to irradiate target volumes with bi-concave outlines

    Energy Technology Data Exchange (ETDEWEB)

    De Neve, W.; Derycke, S.; De Wagter, C. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde

    1995-12-01

    A heuristic planing procedure allowing to obtain a 3-dimensional conformal dose distribution in radiotherapy for target volumes with a bi-concave or multi-concave shape has been developed. The described method is tested on a phantom simulating a pelvic target, described by Brahme.

  18. Measurements of neutron spectrum from stopping-length target irradiated by several tens-MeV/u particles

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro; Takada, Hiroshi; Nakashima, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tanaka, Susumu; Shin, Kazuo; Ono, Shinji

    1997-03-01

    Using a Time-of-Flight technique, we have measured neutron spectra from stopping-length targets bombarded with 68-MeV protons and 100-MeV {alpha}-particles. The measured spectra were used to validate the results calculated by the Quantum Molecular Dynamics (QMD) plus Statistical Decay Model (SDM). The results of QMD plus SDM code agreed fairly well with the experimental data for the light target. On the other hand, the QMD plus SDM gives a larger value than the experimental for the heavy target. (author)

  19. Role of Hypoxia-inducible factor-1 and its target genes in human lung adenocarcinoma cells after photon- versus carbon ion irradiation; Expression HIF-1-abhaengiger Gene in humanen Lungenadenokarzinom (A549)-Zellen und deren Regulation nach Photonen- und Schwerionenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Bill, Verena Maria

    2013-11-26

    Exposed to hypoxia tumor cells are notably resistant to photon irradiation. The hypoxiainducible transcription factor 1α (HIF-1α) seems to play a fundamental role in this resistance, while its role after heavy-ion beam remains unknown. The intention of this study was to determine how A549-cells (non-small-cell lung carcinoma) react in different oxygenation states after irradiation with photons or heavy ions, particularly in regards to their expression of HIF-1 target genes. Resistance of hypoxic A549 cells after photon irradiation was documented by cellular and clonogenic survival. In contrast, cellular survival after heavy-ion irradiation in hypoxic cells was not elevated to normoxic cells. Among the oxygen dependent regulation of HIF-1 target genes, gene expression analyses showed an increased expression of GLUT-1, LDH-A, PDK-1 and VEGF after photon irradiation but not after heavy-ion irradiation after 48 hours in normoxic cells. As expected, CDKN1A as inhibitor of cell cycle progression showed higher expression after both radiation forms; interestingly CDKN1A was also in an oxygen dependent manner lightly upregulated. In western blot analyses we demonstrated a significant increase of HIF-1 and GLUT-1 caused by hypoxia, but only a tendency of increased protein level in hypoxia after photon irradiation and no changes after heavy-ion irradiation. Significantly higher protein level of secreted VEGF-A could be measured 72 hours after photon irradiation in normoxic cells by ELISA analyses. Controversially discussed, I could not detect an association between HIF-1 and SCF or Trx-1 in A549-cells in this study. Whereas Trx-1-expression was neither influenced by changed oxygen partial pressure nor irradiation, I could show increased SCF mRNA by quantitative Real Time-PCR and secreted protein level by ELISA after photon irradiation independent of oxygen state. In summary, this study showed that HIF-1 and its target genes (GLUT-1, LDHA; PDK, VEGF) and also SCF was

  20. Joint Experiments on X-ray/Particle Emission from Plasmas Produced by Laser Irradiating Nano Structured Targets

    Science.gov (United States)

    Hegazy, H.; Allam, S. H.; Chaurasia, S.; Dhareshwar, L.; El-Sherbini, Th. M.; Kunze, H.-J.; Mank, G.; McDaniel, D. H.; Rosinski, M.; Ryc, L.; Stewart, B.; Wolowski, J.; Abd El-Ghany, H.; Abd El-Latif, G.; Abd El-Rahim, F. M.; Bedrane, Z.; Diab, F.; Farrag, A.; Hedwig, R.; Helal, A.; Pardede, M.; Refaie, A.; Sharkawy, H.; El-khatim, A., Sir

    2008-04-01

    The 1st Joint (Host Laboratory) Experiment on laser plasma involving more than twenty scientists from eight countries has been carried out at the Laser and New Materials Laboratory, Faculty of Science, Cairo University, Egypt. It was co-ordinated by the International Atomic Energy Agency (IAEA) and supported through the IAEA and the ICTP (International Centre for Theoretical Physics, Trieste). The main experimental programme was aimed at characterising the possible enhancement of x-ray and particle emission from plasmas produced by laser incidence on nano-structured targets. Laser beams at 1.064 μm of 250 mJ and 532 nm of 165 mJ focused at the target surface using a nanosecond laser type Quantel were used in the present study. In the present experiments nano-copper structures evaporated onto copper bulk disks and nano-gold structures evaporated onto gold ones were used. The thickness of the nano-materials on their bulk material was 1 μm. An ion collector and x-ray semiconductor diode were used to study the ion and x-ray emission, respectively. Both were positioned at the same port at 90° with respect to the target surface and at 90 cm from the surface in the case of the ion collector and 55 cm in the case of the x-ray detector. These experiments were performed at vacuum pressures of (5—8)×10-6 mbar. Comparison of both studies in the case of nano structured targets and bulk targets were performed at different laser fluencies (1×109-1×1012 W/cm2) on the target. A 20% increase of the X-ray emission for nano gold with respect to bulk gold was observed, however, the x-ray emission in the of nano copper and copper was the same.

  1. A TPD and AR based comparison of accelerator neutron irradiation fields between (7)Li and W targets for BNCT.

    Science.gov (United States)

    Tanaka, Kenichi; Endo, Satoru; Yonai, Shunsuke; Baba, Mamoru; Hoshi, Masaharu

    2014-06-01

    The characteristics of moderator assembly dimension was investigated for the usage of (7)Li(p,n) neutrons by 2.3-2.8MeV protons and W(p,n) neutrons by 50MeV protons. The indexes were the treatable protocol depth (TPD) and advantage depth (AD). Consequently, a configuration for W target with the Fe filter, Fluental moderator, Pb reflector showed the TPD of 5.8cm and AD of 9.3cm. Comparable indexes were found for the Li target in a geometry with the MgF2 moderator and Teflon reflector.

  2. The role of repair in the survival of mammalian cells from heavy ion irradiation - Approximation to the ideal case of target theory

    Science.gov (United States)

    Lett, J. T.; Cox, A. B.; Story, M. D.

    1989-01-01

    Experiments are discussed in which the cell-cycle dependency of the repair deficiency of the S/S variant of the L5178Y murine leukemic lymphoblast was examined by treatment with the heavy ions, Ne-20, Si-28, Ar-40, Fe-56, and Nb-93. Evidence from those studies provide support for the notion that as the linear energy transfer of the incident radiation increases the ability of the S/S cell to repair radiation damage decreases until it is eliminated around 500 keV/micron. In the region of the latter linear energy transfer value, the behavior of the S/S cell approximates the ideal case of target theory where post-irradiation metabolism does not influence cell survival.

  3. Experimental benchmark for an improved simulation of absolute soft-x-ray emission from polystyrene targets irradiated with the Nike laser.

    Science.gov (United States)

    Weaver, J L; Busquet, M; Colombant, D G; Mostovych, A N; Feldman, U; Klapisch, M; Seely, J F; Brown, C; Holland, G

    2005-02-04

    Absolutely calibrated, time-resolved spectral intensity measurements of soft-x-ray emission (hnu approximately 0.1-1.0 keV) from laser-irradiated polystyrene targets are compared to radiation-hydrodynamic simulations that include our new postprocessor, Virtual Spectro. This new capability allows a unified, detailed treatment of atomic physics and radiative transfer in nonlocal thermodynamic equilibrium conditions for simple spectra from low-Z materials as well as complex spectra from high-Z materials. The excellent agreement (within a factor of approximately 1.5) demonstrates the powerful predictive capability of the codes for the complex conditions in the ablating plasma. A comparison to data with high spectral resolution (E/deltaE approximately 1000) emphasizes the importance of including radiation coupling in the quantitative simulation of emission spectra.

  4. Protection of normal brain cells from γ-irradiation-induced apoptosis by a mitochondria-targeted triphenyl-phosphonium-nitroxide: a possible utility in glioblastoma therapy.

    Science.gov (United States)

    Huang, Zhentai; Jiang, Jianfei; Belikova, Natalia A; Stoyanovsky, Detcho A; Kagan, Valerian E; Mintz, Arlan H

    2010-10-01

    Glioblastoma multiforme is the most frequent and aggressive primary brain tumor. A strong rationale to identify innovative approaches to treat these tumors is required since treatment failures result in local recurrences and median survivals range from 9 to 12 months. Glioma cells are reported to have less mitochondrial content compared to adjacent normal brain cells. Based on this difference, we suggest a new strategy, utilizing protection of normal brain cells by mitochondria-targeted electron scavengers and antioxidants-nitroxides-thus allowing for the escalation of the radiation doses. In this paper, we report that a conjugate of nitroxide with a hydrophobic cation, triphenyl-phosphonium (TPEY-Tempo), significantly protected brain endothelial cells from γ-irradiation-induced apoptosis while radiosensitizing brain tumor cells. Thus, TPEY-Tempo may be a promising adjunct in the treatment of glioblastoma with the potential to not only prolong survival but also to maintain quality of life and reduce treatment toxicity.

  5. Niobium sputtered Havar foils for the high-power production of reactive [18F]fluoride by proton irradiation of [18O]H2O targets.

    Science.gov (United States)

    Wilson, J S; Avila-Rodriguez, M A; Johnson, R R; Zyuzin, A; McQuarrie, S A

    2008-05-01

    Niobium sputtered Havar entrance foils were used for the production of reactive [(18)F]fluoride by proton irradiation of [(18)O]H(2)O targets under pressurized conditions. The synthesis yield in the routine production of 2-[(18)F]fluoro-2-deoxy-glucose (FDG) was used as an indicative parameter of the reactivity of (18)F. The yield of FDG obtained with (18)F produced in a target with Havar foil was used as a baseline. No statistically significant difference was found in the saturated yields of (18)F when using Havar or Havar-Nb sputtered entrance foils. However, the amount of long-lived radionuclidic impurities decreased more than 10-fold using the Havar-Nb entrance foil. The average decay corrected synthesis yield of FDG, evaluated over a period of more than 2 years, was found to be approximately 5% higher when using a Havar-Nb entrance foil and a marked improvement on the FDG yield consistency was noted. In addition, the frequency of target rebuilding was greatly diminished when using the Nb sputtered entrance foil.

  6. TARGET:?

    National Research Council Canada - National Science Library

    James M Acton

    2014-01-01

      By 2003. as military planners had become worried that the country's long-range conventional weapons, such as cruise missiles, might be too slow to reach hypothetical distant targets that needed to be struck urgently...

  7. Investigation of irradiation effects on highly integrated leading-edge electronic components of diagnostics and control systems for LHD deuterium operation

    Science.gov (United States)

    Ogawa, K.; Nishitani, T.; Isobe, M.; Murata, I.; Hatano, Y.; Matsuyama, S.; Nakanishi, H.; Mukai, K.; Sato, M.; Yokota, M.; Kobuchi, T.; Nishimura, T.; Osakabe, M.

    2017-08-01

    High-temperature and high-density plasmas are achieved by means of real-time control, fast diagnostic, and high-power heating systems. Those systems are precisely controlled via highly integrated electronic components, but can be seriously affected by radiation damage. Therefore, the effects of irradiation on currently used electronic components should be investigated for the control and measurement of Large Helical Device (LHD) deuterium plasmas. For the precise estimation of the radiation field in the LHD torus hall, the MCNP6 code is used with the cross-section library ENDF B-VI. The geometry is modeled on the computer-aided design. The dose on silicon, which is a major ingredient of electronic components, over nine years of LHD deuterium operation shows that the gamma-ray contribution is dominant. Neutron irradiation tests were performed in the OKTAVIAN at Osaka University and the Fast Neutron Laboratory at Tohoku University. Gamma-ray irradiation tests were performed at the Nagoya University Cobalt-60 irradiation facility. We found that there are ethernet connection failures of programmable logic controller (PLC) modules due to neutron irradiation with a neutron flux of 3  ×  106 cm-2 s-1. This neutron flux is equivalent to that expected at basement level in the LHD torus hall without a neutron shield. Most modules of the PLC are broken around a gamma-ray dose of 100 Gy. This is comparable with the dose in the LHD torus hall over nine years. If we consider the dose only, these components may survive more than nine years. For the safety of the LHD operation, the electronic components in the torus hall have been rearranged.

  8. Experimental Study on Fast Electrons Transport in Ultra-intense Laser Irradiated Solid Targets by Transition Radiation

    Science.gov (United States)

    Zhijian, Zheng; Guangcan, Wang; Yuqiu, Gu

    2008-11-01

    The experiment was performed with SILEX laser facility(Ti-saphhire) at LFRC in China. The SILEX parameter: wavelength 0.8μm, duration 35fs, output power 280TW, contrast 5*105, The focal spot φ10μm(F/1.7), intensity on target surface 1*10^19W/cm^2(F/3). The main diagnostic equipments are the electron spectrometer, OMA spectrometer, optical streak camera. Some experimental results are given: The spectrum of optical emission from rear surface is rather narrow around some particular frequencies(1φ, 2φ, 3φ), We ascribe and confirm that the spike-like spectral line that is coherent transition radiation; The coherent light is also seen on time-integrated image with ring-patter due to Weibel instability of the fast electron transport; Obtained experimental cure of target thickness vs OTR image intensity is relative to mean free path of fast electron; The measuring optical transition radiation(OTR) duration of 171ps much longer than 1ps duration of fast electron transport target, the possible explanation is that the OTR duration to be determined magnetic diffusion time.

  9. Safety evaluation report related to the Department of Energy`s proposal for the irradiation of lead test assemblies containing tritium-producing burnable absorber rods in commercial light-water reactors. Project Number 697

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    The NRC staff has reviewed a report, submitted by DOE to determine whether the use of a commercial light-water reactor (CLWR) to irradiate a limited number of tritium-producing burnable absorber rods (TPBARs) in lead test assemblies (LTAs) raises generic issues involving an unreviewed safety question. The staff has prepared this safety evaluation to address the acceptability of these LTAs in accordance with the provision of 10 CFR 50.59 without NRC licensing action. As summarized in Section 10 of this safety evaluation, the staff has identified issues that require NRC review. The staff has also identified a number of areas in which an individual licensee undertaking irradiation of TPBAR LTAs will have to supplement the information in the DOE report before the staff can determine whether the proposed irradiation is acceptable at a particular facility. The staff concludes that a licensee undertaking irradiation of TPBAR LTAs in a CLWR will have to submit an application for amendment to its facility operating license before inserting the LTAs into the reactor.

  10. The generation of purinome-targeted libraries as a means to diversify ATP-mimetic chemical classes for lead finding.

    Science.gov (United States)

    Felder, Eduard R; Badari, Alessandra; Disingrini, Teresa; Mantegani, Sergio; Orrenius, Christian; Avanzi, Nilla; Isacchi, Antonella; Salom, Barbara

    2012-02-01

    The generation of novel chemotypes in support of our oncology research projects expanded in recent years from a canonical design of kinase-targeted compound libraries to a broader interpretation of purinome-targeted libraries (PTL) addressing the specificity of cancer relevant targets such as kinases and ATPases. Successful screening of structurally diverse ATP-binding targets requires compound libraries covering multiple design elements, which may include phosphate surrogate moieties in ATPase inhibitors or far reaching lipophilic residues stabilizing inactive kinase conformations. Here, we exemplify the design and preparation of drug-like combinatorial libraries and report significantly enhanced screening performance on purinomic targets. We compared overall hit rates of PTL with a simultaneously tested unbiased collection of 200,000 compounds and found consistent superiority of the targeted libraries in all cases. We also analyzed the performance of the largest targeted libraries in comparison with each other and often found striking differences in how a specific target responds to various chemotypes and to whole collections.

  11. 225Ac and 223Ra production via 800 MeV proton irradiation of natural thorium targets.

    Science.gov (United States)

    Weidner, J W; Mashnik, S G; John, K D; Ballard, B; Birnbaum, E R; Bitteker, L J; Couture, A; Fassbender, M E; Goff, G S; Gritzo, R; Hemez, F M; Runde, W; Ullmann, J L; Wolfsberg, L E; Nortier, F M

    2012-11-01

    Cross sections for the formation of (225,227)Ac, (223,225)Ra, and (227)Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of (223,225)Ra, (227)Ac and (227)Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of (225)Ac and (223)Ra is a viable production method.

  12. Separation of no-carrier-added Cu-64 from a proton irradiated Ni-64 enriched nickel target

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Jacobsen, U.; Jørgensen, J.C.

    2002-01-01

    are then absorbed on an anion exchange column. Co and Ni are removed from the column by eluting with 72% ethanol-0.3mol/l HCl. Finally, the Cu-64 is eluted with water. For separating Ni from Co isotopes and recovering the Ni-64 target, the eluate of 72% ethanol-0.3 mol/l HCl is evaporated to dryness, the residue...... a cyclotron. The decontamination of Co in Cu fraction is higher than 99% and recoveries of Cu-64 and Ni-64 are higher than 95%. (C) 2002 Elsevier Science Ltd. All rights reserved....

  13. Hot surface ionic line emission and cold K-inner shell emission from petawatt-laser irradiated Cu foil targets

    Energy Technology Data Exchange (ETDEWEB)

    Theobald, W; Akli, K; Clarke, R; Delettrez, J A; Freeman, R R; Glenzer, S; Green, J; Gregori, G; Heathcote, R; Izumi, N; King, J A; Koch, J A; Kuba, J; Lancaster, K; MacKinnon, A J; Key, M; Mileham, C; Myatt, J; Neely, D; Norreys, P A; Park, H; Pasely, J; Patel, P; Regan, S P; Sawada, H; Shepherd, R; Snavely, R; Stephens, R B; Stoeckl, C; Storm, M; Zhang, B; Sangster, T C

    2005-12-13

    A hot, T{sub e} {approx} 2- to 3-keV surface plasma was observed in the interaction of a 0.7-ps petawatt laser beam with solid copper-foil targets at intensities >10{sup 20} W/cm{sup 2}. Copper K-shell spectra were measured in the range of 8 to 9 keV using a single-photon-counting x-ray CCD camera. In addition to K{sub {alpha}} and K{sub {beta}} inner-shell lines, the emission contained the Cu He{sub {alpha}} and Ly{sub {alpha}} lines, allowing the temperature to be inferred. These lines have not been observed previously with ultrafast laser pulses. For intensities less than 3 x 10{sup 18} W/cm{sup 2}, only the K{sub {alpha}} and K{sub {beta}} inner-shell emissions are detected. Measurements of the absolute K{sub {alpha}} yield as a function of the laser intensity are in agreement with a model that includes refluxing and confinement of the suprathermal electrons in the target volume.

  14. Direct detection of delayed high energy electrons from the 181Ta target irradiated by a moderate intensity femtosecond laser pulse

    Science.gov (United States)

    Savel’ev, A.; Chefonov, O.; Ovchinnikov, A.; Agranat, M.; Spohr, K. M.

    2017-03-01

    We depict an experimental study of delayed fast, negatively charged particles from femtosecond laser-plasma interaction at an intensity of I ∼ 1017 W cm‑2. Plates of 2 mm thickness made of 181Ta (∼100% abundance) and natural W were used as targets. We distinguished certain delayed events due to detection of negative H‑, C‑ and O‑ ions. However, most events which were delayed by 0.5–5 μs with respect to the instantaneous plasma formation caused by the laser pulses, were identified as electrons with energies of 3–7 keV. A comparative analysis between the tantalum and tungsten spectra was undertaken. This revealed a close similarity between the measured spectrum for tantalum and the predicted spectrum for electrons arising from to the internal conversion decay of the 6.237 keV nuclear isomeric state in 181Ta.

  15. Molybdenum-99 production from reactor irradiation of molybdenum targets: a viable strategy for enhanced availability of technetium-99m.

    Science.gov (United States)

    Pillai, M R A; Knapp, F F Russ

    2012-08-01

    Fission-produced 99Mo (F 99Mo) is traditionally used for fabrication of 99Mo/99mTc alumina-based column generators. In this paper, several emerging strategies are discussed which are being pursued or have been suggested to overcome the continuing shortages of F 99Mo. In addition to the hopeful eventual success of these proposed new 99Mo and 99mTc production technologies, an additional attractive strategy is the alternative production and use of low specific activity (LSA) 99Mo. This strategy avoids fission and is accomplished by direct activation of molybdenum targets in nuclear reactors, which would preclude sole continued reliance on F 99Mo. The principal focus of this paper is a detailed discussion on the advantages and strategies for enhanced production of LSA 99Mo using an international network of research reactors. Several effective strategies are discussed to obtain 99mTc from LSA 99Mo as well as more efficient use of the alumina-based generator system. The delayed time period between 99Mo production and traditional 99Mo/99mTc alumina column generator manufacture and distribution to user sites results in the loss of more than 50% of 99Mo activity. Another strategy is a paradigm shift in the use of 99Mo by recovering clinical-grade 99mTc from 99Mo solution as an alternative to use of 99Mo/99mTc column generators, thereby avoiding substantial decreased availability of 99Mo from radioactive decay. Implementation of the suggested strategies would be expected to increase availability of 99mTc to the clinical user community by several fold. Additional important advantages for the use of LSA 99Mo include eliminating the need for fission product waste management and precluding proliferation concerns by phasing out the need for high (HEU)- and low (LEU)-enriched uranium targets required for F 99Mo production.

  16. Combinatorial Screening Identifies Novel Promiscuous Matrix Metalloproteinase Activities that Lead to Inhibition of the Therapeutic Target IL-13

    NARCIS (Netherlands)

    Urbach, Carole; Gordon, Nathaniel C; Strickland, Ian; Lowne, David; Joberty-Candotti, Cathy; May, Richard; Herath, Athula; Hijnen, DirkJan; Thijs, Judith L; Bruijnzeel-Koomen, Carla A; Minter, Ralph R; Hollfelder, Florian; Jermutus, Lutz

    2015-01-01

    The practical realization of disease modulation by catalytic degradation of a therapeutic target protein suffers from the difficulty to identify candidate proteases, or to engineer their specificity. We identified 23 measurable, specific, and new protease activities using combinatorial screening of

  17. Gills are an initial target of zinc oxide nanoparticles in oysters Crassostrea gigas, leading to mitochondrial disruption and oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Trevisan, Rafael; Delapedra, Gabriel; Mello, Danielle F.; Arl, Miriam [Department of Biochemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Schmidt, Éder C. [Department of Cell Biology, Embryology and Genetic, Federal University of Santa Catarina, 88049-900 Florianópolis, SC (Brazil); Meder, Fabian; Monopoli, Marco [Centre for Bionano Interactions, University College Dublin, Dublin (Ireland); Cargnin-Ferreira, Eduardo [Federal Institute of Santa Catarina, Campus Garopaba, Laboratory of Histological Markers, 88495-000 Garopaba, SC (Brazil); Bouzon, Zenilda L. [Department of Cell Biology, Embryology and Genetic, Federal University of Santa Catarina, 88049-900 Florianópolis, SC (Brazil); Fisher, Andrew S. [School of Geography, Earth and Environmental Sciences, University of Plymouth, PL4 8AA Plymouth (United Kingdom); Sheehan, David [Department of Biochemistry, University College Cork, Cork (Ireland); Dafre, Alcir L., E-mail: alcir.dafre@ufsc.br [Department of Biochemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil)

    2014-08-15

    hemocyte count). At 24 h post exposure, decreased (−29%) glutathione reductase (GR) activity was observed in gills, but other biochemical responses were observed only after 48 h of exposure: lower GR activity (−28%) and levels of protein thiols (−21%), increased index of lipid peroxidation (+49%) and GPx activity (+26%). In accordance with ultrastructural changes and zinc load, digestive gland showed delayed biochemical responses. Except for a decreased GR activity (−47%) at 48 h post exposure, the biochemical alterations seen in gills were not present in digestive gland. The results indicate that gills are able to incorporate zinc prior (24 h) to digestive gland (48 h), leading to earlier mitochondrial disruption and oxidative stress. Our data suggest that gills are the initial target of ZnONP and that mitochondria are organelles particularly susceptible to ZnONP in C. gigas.

  18. Production Cycle for Large Scale Fission Mo-99 Separation by the Processing of Irradiated LEU Uranium Silicide Fuel Element Targets

    Directory of Open Access Journals (Sweden)

    Abdel-Hadi Ali Sameh

    2013-01-01

    Full Text Available Uranium silicide fuels proved over decades their exceptional qualification for the operation of higher flux material testing reactors with LEU elements. The application of such fuels as target materials, particularly for the large scale fission Mo-99 producers, offers an efficient and economical solution for the related facilities. The realization of such aim demands the introduction of a suitable dissolution process for the applied U3Si2 compound. Excellent results are achieved by the oxidizing dissolution of the fuel meat in hydrofluoric acid at room temperature. The resulting solution is directly behind added to an over stoichiometric amount of potassium hydroxide solution. Uranium and the bulk of fission products are precipitated together with the transuranium compounds. The filtrate contains the molybdenum and the soluble fission product species. It is further treated similar to the in-full scale proven process. The generated off gas stream is handled also as experienced before after passing through KOH washing solution. The generated alkaline fluoride containing waste solution is noncorrosive. Nevertheless fluoride can be selectively bonded as in soluble CaF2 by addition of a mixture of solid calcium hydroxide calcium carbonate to the sand cement mixture used for waste solidification. The generated elevated amounts of LEU remnants can be recycled and retargeted. The related technology permits the minimization of the generated fuel waste, saving environment, and improving processing economy.

  19. Accelerating and guiding of C6 + by an intense laser irradiating on a foil target with a tapered channel

    Science.gov (United States)

    Lv, Chong; Wan, Feng; Hou, Ya-Juan; Hong, Xue-Ren; Jia, Mo-Ran; Sang, Hai-Bo; Xie, Bai-Song

    2017-08-01

    A novel scheme with a tapered channel attached to an ultra-thin carbon foil is proposed to accelerate and guide carbon ions via breakout afterburner mechanism. Also, the problems involved are investigated by using two-dimensional particle-in-cell simulations. It is demonstrated that the tapered channel can efficiently accelerate and guide carbon ions and result in a much better quality beam with an order of magnitude higher in density and 22% larger in cut-off energy than that without the tapered channel. The enhanced reasons are analyzed in detail, which are mainly attributed to the guidance of the longitudinal electric field and the focus of the transverse electric field, as well as the convergence effect of the tapered channel. All of them are certified to guide greatly carbon ions to move along the longitudinal direction. Besides, during the simulation time, the ion beam with a tapered channel can remain eight times smaller in divergence angle than that without the tapered channel. Such a target may be beneficial to many applications such as ion fast ignition in inertial fusion, high-energy physics, and proton therapy.

  20. Production yield of produced radioisotopes from 100 MeV proton beam on lead target for shielding analysis of large accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Jung, Nam Suk; Bae, O Ryun; Lee, Hee Seock [Div. of Advanced Nuclear Engineering, POSTECH, Pohang (Korea, Republic of)

    2014-11-15

    In this work, the production yield of major shielding material, a lead, was investigated using 100 MeV protons of KOMAC accelerator facility. For the analysis of the experimental data, the activity has been calculated using the FLUKA Monte Carlo code and analytical methods. The cross section data and the stopping power in the irradiated assembly were calculated by TALYS and SRIM codes in the analytical method, respectively. Consequently, the experimental production yield of produced radioisotopes was compared with the data that are based on Monte Carlo calculations and analytical studies. In this research, the {sup nat}Pb(p, x) reaction was studied using experimental measurements, Monte Carlo simulations and analytical methods. Rereading to the experimental measurements, we demonstrate that both Monte Carlo simulation and analytical methods could be useful tools for the estimation of production yield of this reaction.

  1. Design, Characterization, and Lead Selection of Therapeutic miRNAs Targeting Huntingtin for Development of Gene Therapy for Huntington's Disease.

    Science.gov (United States)

    Miniarikova, Jana; Zanella, Ilaria; Huseinovic, Angelina; van der Zon, Tom; Hanemaaijer, Evelyn; Martier, Raygene; Koornneef, Annemart; Southwell, Amber L; Hayden, Michael R; van Deventer, Sander J; Petry, Harald; Konstantinova, Pavlina

    2016-03-22

    Huntington's disease (HD) is a neurodegenerative disorder caused by accumulation of CAG expansions in the huntingtin (HTT) gene. Hence, decreasing the expression of mutated HTT (mtHTT) is the most upstream approach for treatment of HD. We have developed HTT gene-silencing approaches based on expression cassette-optimized artificial miRNAs (miHTTs). In the first approach, total silencing of wild-type and mtHTT was achieved by targeting exon 1. In the second approach, allele-specific silencing was induced by targeting the heterozygous single-nucleotide polymorphism (SNP) rs362331 in exon 50 or rs362307 in exon 67 linked to mtHTT. The miHTT expression cassette was optimized by embedding anti-HTT target sequences in ten pri-miRNA scaffolds and their HTT knockdown efficacy, allele selectivity, passenger strand activity, and processing patterns were analyzed in vitro. Furthermore, three scaffolds expressing miH12 targeting exon 1 were incorporated in an adeno-associated viral serotype 5 (AAV5) vector and their HTT knock-down efficiency and pre-miHTT processing were compared in the humanized transgenic Hu128/21 HD mouse model. Our data demonstrate strong allele-selective silencing of mtHTT by miSNP50 targeting rs362331 and total HTT silencing by miH12 both in vitro and in vivo. Ultimately, we show that HTT knock-down efficiency and guide strand processing can be enhanced by using different cellular pri-miRNA scaffolds.

  2. Pulsed irradiation improves target selectivity of infrared laser-evoked gene operator for single-cell gene induction in the nematode C. elegans.

    Directory of Open Access Journals (Sweden)

    Motoshi Suzuki

    Full Text Available Methods for turning on/off gene expression at the experimenter's discretion would be useful for various biological studies. Recently, we reported on a novel microscope system utilizing an infrared laser-evoked gene operator (IR-LEGO designed for inducing heat shock response efficiently in targeted single cells in living organisms without cell damage, thereby driving expression of a transgene under the control of a heat shock promoter. Although the original IR-LEGO can be successfully used for gene induction, several limitations hinder its wider application. Here, using the nematode Caenorhabditis elegans (C. elegans as a subject, we have made improvements in IR-LEGO. For better spatial control of heating, a pulsed irradiation method using an optical chopper was introduced. As a result, single cells of C. elegans embryos as early as the 2-cell stage and single neurons in ganglia can be induced to express genes selectively. In addition, the introduction of site-specific recombination systems to IR-LEGO enables the induction of gene expression controlled by constitutive and cell type-specific promoters. The strategies adopted here will be useful for future applications of IR-LEGO to other organisms.

  3. Identification of Novel Drug Targets and Lead Compounds for Advanced Prostate Cancer through Genomic and Cheminformatic Analyses

    Science.gov (United States)

    2015-08-01

    Med Res Rev 2013;33:1081–118. [18] Guo W, Burris TP, Zhang YH, Huang BL, Mason J, Copeland KC, et al. Genomic sequence of the DAX1 gene: an orphan...191] Maran RR, Thomas A, Roth M, Sheng Z, Esterly N, Pinson D, et al. Farnesoid X receptor deficiency in mice leads to increased intestinal epithelial

  4. Downregulation of chloroplast-targeted beta-amylase leads to a starch-excess phenotype in leaves

    DEFF Research Database (Denmark)

    Scheidig, A.; Fröhlich, A.; Schulze, S.;

    2002-01-01

    A functional screen in Escherichia coli was established to identify potato genes coding for proteins involved in transitory starch degradation. One clone isolated had a sequence very similar to a recently described chloroplast-targeted 5-amylase of Arabidopsis. Expression of the gene in E. coli...... showed that the protein product was a functional beta-amylase that could degrade both starch granules and solubilized amylopectin, while import experiments demonstrated that the beta-amylase was imported and processed into pea chloroplasts. To study the function of the protein in transitory starch...

  5. Return of target material ions leads to a reduced hysteresis in reactive high power impulse magnetron sputtering: Model

    Science.gov (United States)

    Kadlec, Stanislav; Čapek, Jiří

    2017-05-01

    A tendency to disappearing hysteresis in reactive High Power Impulse Magnetron Sputtering (HiPIMS) has been reported previously without full physical explanation. An analytical model of reactive pulsed sputtering including HiPIMS is presented. The model combines a Berg-type model of reactive sputtering with the global HiPIMS model of Christie-Vlček. Both time and area averaging is used to describe the macroscopic steady state, especially the reactive gas balance in the reactor. The most important effect in the presented model is covering of reacted parts of target by the returning ionized metal, effectively lowering the target coverage by reaction product at a given partial pressure. The return probability of ionized sputtered metal has been selected as a parameter to quantify the degree of HiPIMS effects. The model explains the reasons for reduced hysteresis in HiPIMS. The critical pumping speed was up to a factor of 7 lower in reactive HiPIMS compared to the mid-frequency magnetron sputtering. The model predicts reduced hysteresis in HiPIMS due to less negative slope of metal flux to substrates and of reactive gas sorption as functions of reactive gas partial pressure. Higher deposition rate of reactive HiPIMS compared to standard reactive sputtering is predicted for some parameter combinations. Comparison of the model with experiment exhibits good qualitative and quantitative agreement for three material combinations, namely, Ti-O2, Al-O2, and Ti-N2.

  6. Mechanistic validation of a clinical lead stapled peptide that reactivates p53 by dual HDM2 and HDMX targeting.

    Science.gov (United States)

    Wachter, F; Morgan, A M; Godes, M; Mourtada, R; Bird, G H; Walensky, L D

    2016-10-10

    Hydrocarbon-stapled peptides that display key residues of the p53 transactivation domain have emerged as bona fide clinical candidates for reactivating the tumor suppression function of p53 in cancer by dual targeting of the negative regulators HDM2 and HDMX. A recent study questioned the mechanistic specificity of such stapled peptides based on interrogating their capacity to disrupt p53/HDM2 and p53/HDMX complexes in living cells using a new recombinase enhanced bimolecular luciferase complementation platform (ReBiL). Here, we directly evaluate the cellular uptake, intracellular targeting selectivity and p53-dependent cytotoxicity of the clinical prototype ATSP-7041. We find that under standard serum-containing tissue culture conditions, ATSP-7041 achieves intracellular access without membrane disruption, dose-dependently dissociates both p53/HDM2 and p53/HDMX complexes but not an unrelated protein complex in long-term ReBiL experiments, and is selectively cytotoxic to cancer cells bearing wild-type p53 by inducing a surge in p53 protein level. These studies underscore the importance of a thorough stepwise approach, including consideration of the time-dependence of cellular uptake and intracellular distribution, in evaluating and advancing stapled peptides for clinical translation.Oncogene advance online publication, 10 October 2016; doi:10.1038/onc.2016.361.

  7. H-CRRETAWAC-OH, a Lead Structure for the Development of Radiotracer Targeting Integrin α5β1?

    Directory of Open Access Journals (Sweden)

    Roland Haubner

    2014-01-01

    Full Text Available Imaging of angiogenic processes is of great interest in preclinical research as well as in clinical settings. The most commonly addressed target structure for imaging angiogenesis is the integrin αvβ3. Here we describe the synthesis and evaluation of [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH, a radiolabelled peptide designed to selectively target the integrin α5β1. Conjugation of 4-nitrophenyl-(RS-2-[18F]fluoropropionate provided [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH in high radiochemical purity (>95% and a radiochemical yield of approx. 55%. In vitro evaluation showed α5β1 binding affinity in the nanomolar range, whereas affinity to αvβ3 and αIIbβ3 was >50 μM. Cell uptake studies using human melanoma M21 (αvβ3-positive and α5β1-negative, human melanoma M21-L (αvβ3-negative and α5β1-negative, and human prostate carcinoma DU145 (αvβ3-negative and α5β1-positive confirmed receptor-specific binding. The radiotracer was stable in human serum and showed low protein binding. Biodistribution studies showed tumour uptake ranging from 2.5 to 3.5% ID/g between 30 and 120 min post-injection. However, blocking studies and studies using mice bearing α5β1-negative M21 tumours did not confirm receptor-specific uptake of [18F]FProp-Cys*-Arg-Arg-Glu-Thr-Ala-Trp-Ala-Cys*-OH, although this radiopeptide revealed high affinity and substantial selectivity to α5β1 in vitro. Further experiments are needed to study the in vivo metabolism of this peptide and to develop improved radiopeptide candidates suitable for PET imaging of α5β1 expression in vivo.

  8. Small Molecules from Nature Targeting G-Protein Coupled Cannabinoid Receptors: Potential Leads for Drug Discovery and Development

    Directory of Open Access Journals (Sweden)

    Charu Sharma

    2015-01-01

    Full Text Available The cannabinoid molecules are derived from Cannabis sativa plant which acts on the cannabinoid receptors types 1 and 2 (CB1 and CB2 which have been explored as potential therapeutic targets for drug discovery and development. Currently, there are numerous cannabinoid based synthetic drugs used in clinical practice like the popular ones such as nabilone, dronabinol, and Δ9-tetrahydrocannabinol mediates its action through CB1/CB2 receptors. However, these synthetic based Cannabis derived compounds are known to exert adverse psychiatric effect and have also been exploited for drug abuse. This encourages us to find out an alternative and safe drug with the least psychiatric adverse effects. In recent years, many phytocannabinoids have been isolated from plants other than Cannabis. Several studies have shown that these phytocannabinoids show affinity, potency, selectivity, and efficacy towards cannabinoid receptors and inhibit endocannabinoid metabolizing enzymes, thus reducing hyperactivity of endocannabinoid systems. Also, these naturally derived molecules possess the least adverse effects opposed to the synthetically derived cannabinoids. Therefore, the plant based cannabinoid molecules proved to be promising and emerging therapeutic alternative. The present review provides an overview of therapeutic potential of ligands and plants modulating cannabinoid receptors that may be of interest to pharmaceutical industry in search of new and safer drug discovery and development for future therapeutics.

  9. In-situ small-angle x-ray scattering study of nanoparticles in the plasma plume induced by pulsed laser irradiation of metallic targets

    Energy Technology Data Exchange (ETDEWEB)

    Lavisse, L.; Jouvard, J.-M.; Girault, M.; Potin, V.; Andrzejewski, H.; Marco de Lucas, M. C.; Bourgeois, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Universite de Bourgogne, 9 Avenue A. Savary, BP 47870-21078 Dijon Cedex (France); Le Garrec, J.-L.; Carles, S.; Mitchell, J. B. A. [Institut de Physique de Rennes, UMR 6251 CNRS-Universite de Rennes 1, 35042 Rennes Cedex (France); Hallo, L. [CEA CESTA, 15 Avenue des Sablieres CS 60001, 33116 Le Barp Cedex (France); Perez, J. [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex (France); Decloux, J. [Kaluti System, Optique et Laser, Centre Scientifique d' Orsay, 91400 Orsay (France)

    2012-04-16

    Small angle x-ray scattering was used to probe in-situ the formation of nanoparticles in the plasma plume generated by pulsed laser irradiation of a titanium metal surface under atmospheric conditions. The size and morphology of the nanoparticles were characterized as function of laser irradiance. Two families of nanoparticles were identified with sizes on the order of 10 and 70 nm, respectively. These results were confirmed by ex-situ transmission electron microscopy experiments.

  10. Materials irradiation facilities at the high-power Swiss proton accelerator complex

    Science.gov (United States)

    Wagner, Werner; Dai, Yong; Glasbrenner, Heike; Aebersold, Hans-Ulrich

    2007-04-01

    Within the Swiss proton accelerator complex at the Paul-Scherrer-Institute (PSI), several irradiation facilities are operated for investigation of materials behavior under high-dose irradiation conditions as well as for neutron activation analysis and isotope production. In LiSoR (liquid solid reaction), a liquid metal loop connected to the 72 MeV proton accelerator Injector 1, steel samples are irradiated while being in contact with flowing lead-bismuth-eutectic (LBE) at elevated temperatures and under tensile stress. In the spallation neutron source SINQ, the STIP program (SINQ Target Irradiation Program) allows materials irradiation under realistic spallation conditions, i.e. in a mixed spectrum of 570 MeV protons and spallation neutrons. Hundreds of samples, mainly austenitic and ferritic-martensitic steels such as 316L, T91 or F82H, were irradiated to doses up to 20 dpa as part of STIP. These also included steel samples in contact with liquid Hg and liquid LBE. MEGAPIE (MEGAwatt PIlot Experiment), a liquid metal target employing LBE, operated in SINQ during the second half of 2006, can be taken as a materials irradiation facility on its own. Adjacent to the target position, SINQ houses a neutron irradiation rabbit system serving activation analysis and isotope production.

  11. Measurements of spallation neutrons from a thick lead target bombarded with 0.5 and 1.5 GeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro; Takada, Hiroshi; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1997-03-01

    Double differential neutron spectra from a thick lead target bombarded with 0.5 and 1.5 GeV protons have been measured with the time-of-flight technique. In order to obtain the neutron spectra without the effect of the flight time fluctuation by neutron scattering in the target, an unfolding technique has also been employed in the low energy region below 3 MeV. The measured data have been compared with the calculated results of NMTC/JAERI-MCNP-4A code system. It has been found that the code system gives about 50 % lower neutron yield than the experimental ones in the energy region between 20 and 80 MeV for both incident energies. The disagreements, however, have been improved well by taking account of the inmedium nucleon-nucleon scattering cross sections in the NMTC/JAERI code. (author)

  12. Target identification, lead optimization and antitumor evaluation of some new 1,2,4-triazines as c-Met kinase inhibitors.

    Science.gov (United States)

    El-Wakil, Marwa H; Ashour, Hayam M; Saudi, Manal N; Hassan, Ahmed M; Labouta, Ibrahim M

    2017-08-01

    In silico target fishing approach using PharmMapper server identified c-Met kinase as the selective target for our previously synthesized compound NCI 748494/1. This approach was validated by in vitro kinase assay which showed that NCI 748494/1 possessed promising inhibitory activity against c-Met kinase (IC50=31.70μM). Assessment of ADMET profiling, drug-likeness, drug score as well as docking simulation for the binding pose of that compound in the active site of c-Met kinase domain revealed that NCI 748494/1 could be considered as a promising drug lead. Based on target identification and validation, it was observed that there is structure similarity between NCI 748494/1 and the reported type II c-Met kinase inhibitor BMS-777607. Optimization of our lead NCI 748494/1 furnished newly synthesized 1,2,4-triazine derivatives based on well-established structure-activity relationships, whereas three compounds namely; 4d, 7a and 8c displayed excellent in vitro cytotoxicity against three c-Met addicted cancer cell lines; A549 (lung adenocarcinoma), HT-29 (colon cancer) and MKN-45 (gastric carcinoma); with IC50 values in the range 0.01-1.86µM. In vitro c-Met kinase assay showed 8c to possess the highest c-Met kinase inhibition profile (IC50=4.31µM). Docking of the active compounds in c-Met kinase active site revealed strong binding interactions comparable to the lead NCI 748494/1 and BMS-777607, suggesting that c-Met inhibition is very likely to be the mechanism of the antitumor effect of these derivatives. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Review and research analysis of computational target methods using BioRuby and in silico screening of herbal lead compounds against pancreatic cancer using R programming.

    Science.gov (United States)

    Jayadeepa, R M; Ray, Ankita; Naik, Dhaval; Sanyal, Debendra Nath; Shah, Disha

    2014-01-01

    Plants and their natural components sophisticated with the cornerstone of traditional conventional medicinal system throughout the globe for many years and extend to furnish mankind with latest remedies. Natural Products act as lead molecules for the synthesis of various potent drugs. In the current research a study is conducted on herbal small molecule and their potential binding chemical affinity to the effect or molecules of major diseases such as pancreatic cancer. Clinical studies demonstrate correlation between Cyclin- Dependent Kinase 4 (CDK4) and malignant progression of Pancreatic Cancer. Using Bioruby Gem's we were able to analyze better characteristics of the target protein. VegaZZ and NAMD were used to minimize the energy of the target protein. Therefore identification of effective, well- tolerated targets was analyzed. Further the target protein was subjected to docking with the anti cancer inhibitors which represents a rational chemo preventive strategy using AutoDock Vina. Later using the dock score top ranked phytochemicals were analyzed for Toxicity Analysis. Using the BioRuby gem we were able to measure the distance between the amino acid. Various R scripting libraries were used to hunt the best leads, as in this case the phytochemicals. Phytochemicals such as Wedelolactones and Catechin were analyzed computationally. This study has presented the various effects of naturally occurring anti pancreatic cancer compounds Catechin, Wedelolactones that inhibits Cyclin Dependent Kinase 4. The study results reveal that compounds use less binding energy to CDK4 and inhibit its activity. Future investigation of other various wet lab studies such as cell line studies will confirm results of these two herbal chemical formulations potential ones for treating Pancreatic Cancer.

  14. Pathways for the release of polonium from a lead-bismuth spallation target (thermochemical calculation); Verfluechtigungspfade des Poloniums aus einem Pb-Bi-Spallationstarget (Thermochemische Kalkulation)

    Energy Technology Data Exchange (ETDEWEB)

    Eichler, B.; Neuhausen, J

    2004-06-01

    An analysis of literature data for the thermochemical constants of polonium reveals considerable discrepancies in the relations of these data among each other as well as in their expected trends within the chalcogen group. This fact hinders a reliable assessment of possible reaction paths for the release of polonium from a liquid lead-bismuth spallation target. In this work an attempt is made to construct a coherent data set for the thermochemical properties of polonium and some of its compounds that are of particular importance with respect to the behaviour of polonium in a liquid Pb-Bi target. This data set is based on extrapolations using general trends throughout the periodic table and, in particular, within the chalcogen group. Consequently, no high accuracy should be attributed to the derived data set. However, the data set derived in this work is consistent with definitely known experimental data. Furthermore, it complies with the general trends of physicochemical properties within the chalcogen group. Finally, well known relations between thermochemical quantities are fulfilled by the data derived in this work. Thus, given the lack of accurate experimental data it can be regarded as best available data. Thermochemical constants of polonium hydride, lead polonide and polonium dioxide are derived based on extrapolative procedures. Furthermore, the possibility of formation of the gaseous intermetallic molecule BiPo, which has been omitted from discussion up to now, is investigated. From the derived thermochemical data the equilibrium constants of formation, release and dissociation reactions are calculated for different polonium containing species. Furthermore equilibrium constants are determined for the reaction of lead polonide and polonium dioxide with hydrogen, water vapour and the target components lead and bismuth. The most probable release pathways are discussed. From thermochemical evaluations polonium is expected to be released from liquid lead

  15. Continuous activation of Nrf2 and its target antioxidant enzymes leads to arsenite-induced malignant transformation of human bronchial epithelial cells.

    Science.gov (United States)

    Yang, Xu; Wang, Dapeng; Ma, Yuan; Xu, Xiguo; Zhu, Zhen; Wang, Xiaojuan; Deng, Hanyi; Li, Chunchun; Chen, Min; Tong, Jian; Yamanaka, Kenzo; An, Yan

    2015-12-01

    Long-term exposure to arsenite leads to human lung cancer, but the underlying mechanisms of carcinogenesis remain obscure. The transcription factor of nuclear factor-erythroid-2 p45-related factor (Nrf2)-mediated antioxidant response represents a critical cellular defense mechanism and protection against various diseases. Paradoxically, emerging data suggest that the constitutive activation of Nrf2 is associated with cancer development, progression and chemotherapy resistance. However, the role of Nrf2 in the occurrence of cancer induced by long-term arsenite exposure remains to be fully understood. By establishing transformed human bronchial epithelial (HBE) cells via chronic low-dose arsenite treatment, we showed that, in acquiring this malignant phenotype, continuous low level of ROS and sustained enhancement of Nrf2 and its target antioxidant enzyme levels were observed in the later-stage of arsenite-induced cell transformation. The downregulation of Keap1 level may be responsible for the over-activation of Nrf2 and its target enzymes. To validate these observations, Nrf2 was knocked down in arsenite-transformed HBE cells by SiRNA transfection, and the levels of Nrf2 and its target antioxidant enzymes, ROS, cell proliferation, migration, and colony formation were determined following these treatments. Results showed that blocked Nrf2 expression significantly reduced Nrf2 and its target antioxidant enzyme levels, restored ROS levels, and eventually suppressed cell proliferation, migration, and colony formation of the transformed cells. In summary, the results of the study strongly suggested that the continuous activation of Nrf2 and its target antioxidant enzymes led to the over-depletion of intracellular ROS levels, which contributed to arsenite-induced HBE cell transformation. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Proton-induced Polonium Production in Lead

    Science.gov (United States)

    Lorenz, T.; Dai, Y.; Schumann, D.; Türler, A.

    2014-05-01

    An appropriate experimental approach is described from which information can be obtained on the amounts of radiotoxic polonium isotopes 208-210Po produced in a lead spallation target during an irradiation period of 16 months from 2000 to 2001. Lead samples from a central position near the beam entry were dissolved and spontaneous deposition of polonium on silver discs was used to prepare thin layer samples for α-counting. The evaluated results show a good correlation to the gradient of the proton beam profile.

  17. Ion-stimulated gas desorption yields of coated (Au, Ag, Pd) stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Malabaila, M; Taborelli, M

    2005-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy Ion Accelerator (LINAC 3), has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting on different accelerator-type vacuum chambers. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, and palladium-coated 316LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analysed for chemical composition by X-ray Photoemission Spectroscopy (XPS). The large effective desorption yield of 2 x 10**4 molecules/ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble metal coating by up to 2 orders of magnitude. In addition, the effectiveness of beam scrubbing with heavy ions and the consequence of a subsequent venting on the desorption yields of a beam-scrubbed vacuum chamber are described. Practical consequences for the vacuum system of the future Low Energy Ion Ring (LEIR) are discussed.

  18. Radiochemical Determination of Polonium in Liquid Metal Spallation Targets

    Science.gov (United States)

    Hammer, B.; Schumann, D.; Neuhausen, J.; Wohlmuther, M.; Türler, A.

    2014-05-01

    The MEGAPIE target, consisting of 82 litres of lead-bismuth eutectic (LBE), was irradiated close to the megawatt range (0.8 MW) from August to December 2006 in the SINQ facility at PSI. After a cooling period of 5 years, a post-irradiation examination (PIE) program was started and samples were taken from different positions in the target. In this paper we focus on the measurement of α-emitting 208-210Po in the MEGAPIE target. The experimental results are compared with theoretical predictions obtained by FLUKA and MCNPX calculations.

  19. Generation of a quasi-monoenergetic high energy proton beam from a vacuum-sandwiched double layer target irradiated by an ultraintense laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Nam Kim, Kyung; Lee, Kitae, E-mail: klee@kaeri.re.kr; Hee Park, Seong; Young Lee, Ji; Uk Jeong, Young; Vinokurov, Nikolay [Center for Quantum-Beam-based Radiation Research, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Gi Kim, Yong [Department of Physics, Kongju National University, Kongju (Korea, Republic of)

    2014-04-15

    An acceleration mechanism to generate a high energy proton beam with a narrow energy spread in the laser-induced plasma acceleration of a proton beam is proposed; this mechanism employs two thin foils separated by a narrow vacuum gap. Instead of a thin sheath field at the plasma surfaces, it utilizes an electrostatic field formed in the bulk of the plasma. From a one-dimensional fluid analysis, it has been found that with an appropriate target thickness, protons on the front surface of the second layer can be fed into the plasma, in which the protons are accelerated by an electrostatic field built into the bulk of the plasma. This leads to a proton beam with higher energy and a narrower energy spread than those accelerated at the rear surface of the second layer. The acceleration mechanism is also verified by a two-dimensional particle-in-cell simulation. With a 27-fs long and 2×10{sup 19} W/cm{sup 2} intense laser pulse, a proton beam with an 18-MeV peak energy and a 35% energy spread is generated. The peak energy is higher than that from the rear surface of the second layer by a factor of 3.

  20. Irradiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Howe, L.M

    2000-07-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization.

  1. Regulation of food irradiation and detection of irradiated food

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, P.B. [Institute of Geological and Nuclear Sciences, Lower Hutt (New Zealand)

    1998-12-31

    The main international standards for irradiated foods are those produced by the Codex Alimentarius Commission. The international regulatory environment is now favourable towards irradiated foods. Most countries still regulate on a food-by-food, case-by-case basis. However in Asia there is movement towards a Harmonised Regulation for Irradiated Foods. The WHO believes that irradiated foods may be safely irradiated at any dose above 10 kGy. This may lead to the Codex maximum dose being raised or abandoned. If this occurs there are opportunities to produce shelf-stable foods in lightweight packaging that last for years at room temperature. Detection methods for irradiated foods are now available and may assist to reassure consumers that labelling regulations can be enforced. (author)

  2. Proton irradiation effects on beryllium - A macroscopic assessment

    Science.gov (United States)

    Simos, Nikolaos; Elbakhshwan, Mohamed; Zhong, Zhong; Camino, Fernando

    2016-10-01

    Beryllium, due to its excellent neutron multiplication and moderation properties, in conjunction with its good thermal properties, is under consideration for use as plasma facing material in fusion reactors and as a very effective neutron reflector in fission reactors. While it is characterized by unique combination of structural, chemical, atomic number, and neutron absorption cross section it suffers, however, from irradiation generated transmutation gases such as helium and tritium which exhibit low solubility leading to supersaturation of the Be matrix and tend to precipitate into bubbles that coalesce and induce swelling and embrittlement thus degrading the metal and limiting its lifetime. Utilization of beryllium as a pion production low-Z target in high power proton accelerators has been sought both for its low Z and good thermal properties in an effort to mitigate thermos-mechanical shock that is expected to be induced under the multi-MW power demand. To assess irradiation-induced changes in the thermal and mechanical properties of Beryllium, a study focusing on proton irradiation damage effects has been undertaken using 200 MeV protons from the Brookhaven National Laboratory Linac and followed by a multi-faceted post-irradiation analysis that included the thermal and volumetric stability of irradiated beryllium, the stress-strain behavior and its ductility loss as a function of proton fluence and the effects of proton irradiation on the microstructure using synchrotron X-ray diffraction. The mimicking of high temperature irradiation of Beryllium via high temperature annealing schemes has been conducted as part of the post-irradiation study. This paper focuses on the thermal stability and mechanical property changes of the proton irradiated beryllium and presents results of the macroscopic property changes of Beryllium deduced from thermal and mechanical tests.

  3. Lead Optimization of 2-Cyclohexyl-N-[(Z-(3-methoxyphenyl/3-hydroxyphenyl methylidene]hydrazinecarbothioamides for Targeting the HER-2 Overexpressed Breast Cancer Cell Line SKBr-3

    Directory of Open Access Journals (Sweden)

    Mashooq A. Bhat

    2015-10-01

    Full Text Available Lead derivatives of 2-cyclohexyl-N-[(Z-(3-methoxyphenyl/3-hydroxyphenyl methylidene]hydrazinecarbothioamides 1–18 were synthesized, characterized and evaluated in vitro against HER-2 overexpressed breast cancer cell line SKBr-3. All the compounds showed activity against HER-2 overexpressed SKBr-3 cells with IC50 = 17.44 ± 0.01 µM to 53.29 ± 0.33 µM. (2Z-2-(3-Hydroxybenzylidene-N-(3-methoxyphenylhydrazinecarbothioamide (12, IC50 = 17.44 ± 0.01 µM was found to be most potent compound of this series targeting HER-2 overexpressed breast cancer cells compared to the standard drug 5-fluorouracil (5-FU (IC50 = 38.58 ± 0.04 µM. Compound 12 inhibited the cellular proliferation via DNA degradation.

  4. Effect of neon plasma pre-irradiation on surface morphology and deuterium retention of tungsten

    NARCIS (Netherlands)

    Cheng, L.; De Temmerman, G.; van Emmichoven, P. A. Zeijlma; Ji, G.; Zhou, H. B.; Wang, B.; Yuan, Y.; Zhang, Y.; Lu, G. H.

    2015-01-01

    Neon and deuterium plasma irradiation of polycrystalline tungsten targets have been performed at high fluxes of ∼1024 ions m−2 s−1 to study the interaction of neon with tungsten and the influence of neon on deuterium retention. Tungsten exposure to neon plasma leads to the

  5. 高速气流中激光加热平板数值模拟与分析%Numerical simulation of plane target in airflow under laser irradiation

    Institute of Scientific and Technical Information of China (English)

    胡鹏; 陈发良

    2011-01-01

    A model of a plane target under laser irradiation is used to numerically simulate the temperature distribution in different speed airflow, using the thermal coupling method of gas and solid. The results show that there is a higher equilibrium temperature over the plane target when there is no laser irradiation, and the heat transfer coefficient between air and the plane tar-get increases with the airflow speed; with a maximum value occurring at the front edge of the target, it declines along the target length. When under laser irradiation in different cases, the temperature distribution in the plane is analyzed carefully, and the in-fluence of aerodynamic heating, forced convection cooling and laser heating is focused to compare their thermal competition,which shows that the temperature distributions in the target results from several thermal competition ultimately.%采用流固耦合方法,数值模拟了高速流场中激光作用下来流速度对平板温度分布的影响.结果表明:无激光辐照时,高速气流中平板有较高的气动生热平衡温度,且平板-气流之间的换热系数随来流速度增大而增大;在平板前沿换热系数增长最快,沿平板长度方向增速趋于平缓.分析了激光辐照时高速气流中激光加热平板的温度分布情况,考察了来流速度不同时,气动生热、散热和激光辐照对平板温度的影响,给出了激光辐照后的温升情况和温度分布,分析了在不同速度来流下,对流散热、摩擦生热和激光加热之间的竞争关系,结果表明,平板温度具体分布主要是加热过程竞争的结果.

  6. Efficient multi-keV x-ray generation from a high-Z target irradiated with a clean ultra-short laser pulse.

    Science.gov (United States)

    Zhang, Z; Nishikino, M; Nishimura, H; Kawachi, T; Pirozhkov, A S; Sagisaka, A; Orimo, S; Ogura, K; Yogo, A; Okano, Y; Ohshima, S; Fujioka, S; Kiriyama, H; Kondo, K; Shimomura, T; Kanazawa, S

    2011-02-28

    Kα line emissions from Mo and Ag plates were experimentally studied using clean, ultrahigh-intensity femtosecond laser pulses. The absolute yields of Kα x-rays at 17 keV from Mo and 22 keV from Ag were measured as a function of the laser pulse contrast ratio and irradiation intensity. Significantly enhanced Kα yields were obtained for both Mo and Ag by employing high contrast ratios and irradiances. Conversion efficiencies of 4.28×10⁻⁵/sr for Mo and 4.84×10⁻⁵/sr for Ag, the highest values obtained to date, were demonstrated with contrast ratios in the range 10⁻¹⁰ to 10⁻¹¹.

  7. Ecotoxicology: Lead

    Science.gov (United States)

    Scheuhammer, A.M.; Beyer, W.N.; Schmitt, C.J.; Jorgensen, Sven Erik; Fath, Brian D.

    2008-01-01

    Lead (Pb) is a naturally occurring metallic element; trace concentrations are found in all environmental media and in all living things. However, certain human activities, especially base metal mining and smelting; combustion of leaded gasoline; the use of Pb in hunting, target shooting, and recreational angling; the use of Pb-based paints; and the uncontrolled disposal of Pb-containing products such as old vehicle batteries and electronic devices have resulted in increased environmental levels of Pb, and have created risks for Pb exposure and toxicity in invertebrates, fish, and wildlife in some ecosystems.

  8. Ginger components as new leads for the design and development of novel multi-targeted anti-Alzheimer’s drugs: a computational investigation

    Directory of Open Access Journals (Sweden)

    Azam F

    2014-10-01

    Full Text Available Faizul Azam,1,2 Abdualrahman M Amer,1 Abdullah R Abulifa,1 Mustafa M Elzwawi1 1Faculty of Pharmacy, Misurata University, Misurata, Libya; 2Department of Pharmaceutical Chemistry, Nims Institute of Pharmacy, Nims University, Jaipur, Rajasthan, India Abstract: Ginger (Zingiber officinale, despite being a common dietary adjunct that contributes to the taste and flavor of foods, is well known to contain a number of potentially bioactive phytochemicals having valuable medicinal properties. Although recent studies have emphasized their benefits in Alzheimer’s disease, limited information is available on the possible mechanism by which it renders anti-Alzheimer activity. Therefore, the present study seeks to employ molecular docking studies to investigate the binding interactions between active ginger components and various anti-Alzheimer drug targets. Lamarckian genetic algorithm methodology was employed for docking of 12 ligands with 13 different target proteins using AutoDock 4.2 program. Docking protocol was validated by re-docking of all native co-crystallized ligands into their original binding cavities exhibiting a strong correlation coefficient value (r2=0.931 between experimentally reported and docking predicted activities. This value suggests that the approach could be a promising computational tool to aid optimization of lead compounds obtained from ginger. Analysis of binding energy, predicted inhibition constant, and hydrophobic/hydrophilic interactions of ligands with target receptors revealed acetylcholinesterase as most promising, while c-Jun N-terminal kinase was recognized as the least favorable anti-Alzheimer’s drug target. Common structural requirements include hydrogen bond donor/acceptor area, hydrophobic domain, carbon spacer, and distal hydrophobic domain flanked by hydrogen bond donor/acceptor moieties. In addition, drug-likeness score and molecular properties responsible for a good pharmacokinetic profile were calculated

  9. Food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Webb, T.

    1986-01-01

    The proposed use of gamma radiation from cobalt 60 and cesium 137 for food irradiation in the United Kingdom is discussed, with particular reference to the possible dangers and disadvantages to the safety and wholesomeness of the food.

  10. [Food irradiation].

    Science.gov (United States)

    Migdał, W

    1995-01-01

    A worldwide standard on food irradiation was adopted in 1983 by Codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Institute of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19MeV, 1 kW) and an industrial unit Elektronika (10MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permission for irradiation for: spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables.

  11. Materials considerations in accelerator targets

    Science.gov (United States)

    Peacock, H. B.; Iyer, N. C.; Louthan, M. R.

    1995-09-01

    Future nuclear materials production and/or the burn-up of long lived radioisotopes may be accomplished through the capture of spallation produced neutrons in accelerators. Aluminum clad-lead and/or lead alloys has been proposed as a spallation target. Aluminum was the cladding choice because of the low neutron absorption cross section, fast radioactivity decay, high thermal conductivity, and excellent fabricability. Metallic lead and lead oxide powders were considered for the target core with the fabrication options being casting or powder metallurgy (PM). Scoping tests to evaluate gravity casting, squeeze casting, and casting and swaging processes showed that, based on fabricability and heat transfer considerations, squeeze casting was the preferred option for manufacture of targets with initial core cladding contact. Thousands of aluminum clad aluminum-lithium alloy core targets and control rods for tritium production have been fabricated by coextrusion processes and successfully irradiated in the SRS reactors. Tritium retention in, and release from, the coextruded product was modeled from experimental and operational data. The model assumed that tritium atoms, formed by the 6Li(n,a)3He reaction, were produced in solid solution in the Al-Li alloy. Because of the low solubility of hydrogen isotopes in aluminum alloys, the irradiated Al-Li rapidly became supersaturated in tritium. Newly produced tritium atoms were trapped by lithium atoms to form a lithium tritide. The effective tritium pressure required for trap or tritide stability was the equilibrium decomposition pressure of tritium over a lithium tritide-aluminum mixture. The temperature dependence of tritium release was determined by the permeability of the cladding to tritium and the local equilibrium at the trap sites. The model can be used to calculate tritium release from aluminum clad, aluminum-lithium alloy targets during postulated accelerator operational and accident conditions. This paper describes

  12. Feasibility studies for quarkonium production at a fixed-target experiment using the LHC proton and lead beams (AFTER@LHC)

    CERN Document Server

    Massacrier, L; Fleuret, F; Hadjidakis, C; Kikola, D; Lansberg, J P; Shao, H -S

    2015-01-01

    Used in the fixed-target mode, the multi-TeV LHC proton and lead beams allow for studies of heavy-flavour hadroproduction with unprecedented precision at backward rapidities - far negative Feyman-x - using conventional detection techniques. At the nominal LHC energies, quarkonia can be studies in detail in p+p, p+d and p+A collisions at sqrt(s_NN) ~ 115 GeV as well as in Pb+p and Pb+A collisions at sqrt(s_NN) ~ 72 GeV with luminosities roughly equivalent to that of the collider mode, i.e. up to 20 fb-1 yr-1 in p+p and p+d collisions, up to 0.6 fb-1 yr-1 in p+A collisions and up to 10 nb-1 yr-1 in Pb+A collisions. In this paper, we assess the feasibility of such studies by performing fast simulations using the performance of a LHCb-like detector.

  13. Feasibility Studies for Quarkonium Production at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC

    Directory of Open Access Journals (Sweden)

    L. Massacrier

    2015-01-01

    Full Text Available Being used in the fixed-target mode, the multi-TeV LHC proton and lead beams allow for studies of heavy-flavour hadroproduction with unprecedented precision at backward rapidities, far negative Feynman-x, using conventional detection techniques. At the nominal LHC energies, quarkonia can be studied in detail in p+p, p+d, and p+A collisions at sNN≃115 GeV and in Pb + p and Pb + A collisions at sNN≃72 GeV with luminosities roughly equivalent to that of the collider mode that is up to 20 fb−1 yr−1 in p+p and p+d collisions, up to 0.6 fb−1 yr−1 in p+A collisions, and up to 10 nb−1 yr−1 in Pb + A collisions. In this paper, we assess the feasibility of such studies by performing fast simulations using the performance of a LHCb-like detector.

  14. Large-angle production of charged pions by 3 GeV/c - 12.9 GeV/c protons on beryllium, aluminium and lead targets

    CERN Document Server

    Catanesi, M.G.; Edgecock, R.; Ellis, Malcolm; Soler, F.J.P.; Gossling, C.; Bunyatov, S.; Krasnoperov, A.; Popov, B.; Serdiouk, V.; Tereschenko, V.; Di Capua, E.; Vidal-Sitjes, G.; Artamonov, A.; Giani, S.; Gilardoni, S.; Gorbunov, P.; Grant, A.; Grossheim, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Panman, J.; Papadopoulos, I.; Tcherniaev, E.; Tsukerman, I.; Veenhof, R.; Wiebusch, C.; Zucchelli, P.; Blondel, A.; Borghi, S.; Morone, M.C.; Prior, G.; Schroeter, R.; Meurer, C.; Gastaldi, U.; Mills, G.B.; Graulich, J.S.; Gregoire, G.; Bonesini, M.; Ferri, F.; Kirsanov, M.; Bagulya, A.; Grichine, V.; Polukhina, N.; Palladino, V.; Coney, L.; Schmitz, D.; Barr, G.; De Santo, A.; Bobisut, F.; Gibin, D.; Guglielmi, A.; Mezzetto, M.; Dumarchez, J.; Dore, U.; Orestano, D.; Pastore, F.; Tonazzo, A.; Tortora, L.; Booth, C.; Howlett, L.; Bogomilov, M.; Chizhov, M.; Kolev, D.; Tsenov, R.; Piperov, Stefan; Temnikov, P.; Apollonio, M.; Chimenti, P.; Giannini, G.; Burguet-Castell, J.; Cervera-Villanueva, A.; Gomez-Cadenas, J.J.; Martin-Albo, J.; Novella, P.; Sorel, M.; CERN. Geneva

    2008-01-01

    Measurements of the double-differential $\\pi^{\\pm}$ production cross-section in the range of momentum $100 \\MeVc \\leq p < 800 \\MeVc$ and angle $0.35 \\rad \\leq \\theta < 2.15 \\rad$ in proton--beryllium, proton--aluminium and proton--lead collisions are presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12.9 \\GeVc hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections at six incident proton beam momenta (3 \\GeVc, 5 \\GeVc, 8 \\GeVc, 8.9 \\GeVc (Be only), 12 \\GeVc and 12.9 \\GeVc (Al only)) and compared to previously available data.

  15. Large-angle production of charged pions by 3 GeV/c - 12.9 GeV/c protons on beryllium, aluminium and lead targets

    CERN Document Server

    Catanesi, M G; Edgecock, R; Ellis, Malcolm; Soler, F J P; Gössling, C; Bunyatov, S; Krasnoperov, A; Popov, B; Serdiouk, V; Tereschenko, V; Di Capua, E; Vidal-Sitjes, G; Artamonov, A; Giani, S; Gilardoni, S; Gorbunov, P; Grant, A; Grossheim, A; Ivanchenko, V; Kayis-Topaksu, A; Panman, J; Papadopoulos, I; Chernyaev, E; Tsukerman, I; Veenhof, R; Wiebusch, C; Zucchelli, P; Blondel, A; Borghi, S; Morone, M C; Prior, G; Schroeter, R; Meurer, C; Gastaldi, U; Mills, G B; Graulich, J S; Grégoire, G; Bonesini, M; Ferri, F; Kirsanov, M; Bagulya, A; Grichine, V; Polukhina, N; Palladino, V; Coney, L; Schmitz, D; Barr, G; De Santo, A; Bobisut, F; Gibin, D; Guglielmi, A; Mezzetto, M; Dumarchez, J; Dore, U; Orestano, D; Pastore, F; Tonazzo, A; Tortora, L; Booth, C; Howlett, L; Bogomilov, M; Chizhov, M; Kolev, D; Tsenov, R; Piperov, Stefan; Temnikov, P; Apollonio, M; Chimenti, P; Giannini, G; Burguet-Castell, J; Cervera-Villanueva, A; Gómez-Cadenas, J J; Martín-Albo, J; Novella, P; Sorel, M; CERN. Geneva

    2008-01-01

    Measurements of the double-differential $\\pi^{\\pm}$ production cross-section in the range of momentum $100 \\MeVc \\leq p < 800 \\MeVc$ and angle $0.35 \\rad \\leq \\theta < 2.15 \\rad$ in proton--beryllium, proton--aluminium and proton--lead collisions are presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 \\GeVc to 12.9 \\GeVc hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections at six incident proton beam momenta (3 \\GeVc, 5 \\GeVc, 8 \\GeVc, 8.9 \\GeVc (Be only), 12 \\GeVc and 12.9 \\GeVc (Al only)) and compared to previously available data.

  16. Targeting the unique methylation pattern of androgen receptor (AR) promoter in prostate stem/progenitor cells with 5-aza-2'-deoxycytidine (5-AZA) leads to suppressed prostate tumorigenesis.

    Science.gov (United States)

    Tian, Jing; Lee, Soo Ok; Liang, Liang; Luo, Jie; Huang, Chiung-Kuei; Li, Lei; Niu, Yuanjie; Chang, Chawnshang

    2012-11-16

    Androgen receptor (AR) expression surveys found that normal prostate/prostate cancer (PCa) stem/progenitor cells, but not embryonic or mesenchymal stem cells, expressed little AR with high methylation in the AR promoter. Mechanism dissection revealed that the differential methylation pattern in the AR promoter could be due to differential expression of methyltransferases and binding of methylation binding protein to the AR promoter region. The low expression of AR in normal prostate/PCa stem/progenitor cells was reversed after adding 5-aza-2'-deoxycytidine, a demethylating agent, which could then lead to decreased stemness and drive cells into a more differentiated status, suggesting that the methylation in the AR promoter of prostate stem/progenitor cells is critical not only in maintaining the stemness but also critical in protection of cells from differentiation. Furthermore, induced AR expression, via alteration of its methylation pattern, led to suppression of the self-renewal/proliferation of prostate stem/progenitor cells and PCa tumorigenesis in both in vitro assays and in vivo orthotopic xenografted mouse studies. Taken together, these data prove the unique methylation pattern of AR promoter in normal prostate/PCa stem/progenitor cells and the influence of AR on their renewal/proliferation and differentiation. Targeting PCa stem/progenitor cells with alteration of methylated AR promoter status might provide a new potential therapeutic approach to battle PCa because the PCa stem/progenitor cells have high tumorigenicity.

  17. Radioprotection of targeted and bystander cells by methylproamine.

    Science.gov (United States)

    Burdak-Rothkamm, Susanne; Smith, Andrea; Lobachevsky, Pavel; Martin, Roger; Prise, Kevin M

    2015-03-01

    Radioprotective agents are of interest for application in radiotherapy for cancer and in public health medicine in the context of accidental radiation exposure. Methylproamine is the lead compound of a class of radioprotectors which act as DNA binding anti-oxidants, enabling the repair of transient radiation-induced oxidative DNA lesions. This study tested methylproamine for the radioprotection of both directly targeted and bystander cells. T98G glioma cells were treated with 15 μM methylproamine and exposed to (137)Cs γ-ray/X-ray irradiation and He(2+) microbeam irradiation. Radioprotection of directly targeted cells and bystander cells was measured by clonogenic survival or γH2AX assay. Radioprotection of directly targeted T98G cells by methylproamine was observed for (137)Cs γ-rays and X-rays but not for He(2+) charged particle irradiation. The effect of methylproamine on the bystander cell population was tested for both X-ray irradiation and He(2+) ion microbeam irradiation. The X-ray bystander experiments were carried out by medium transfer from irradiated to non-irradiated cultures and three experimental designs were tested. Radioprotection was only observed when recipient cells were pretreated with the drug prior to exposure to the conditioned medium. In microbeam bystander experiments targeted and nontargeted cells were co-cultured with continuous methylproamine treatment during irradiation and postradiation incubation; radioprotection of bystander cells was observed. Methylproamine protected targeted cells from DNA damage caused by γ-ray or X-ray radiation but not He(2+) ion radiation. Protection of bystander cells was independent of the type of radiation which the donor population received.

  18. Influence of the reactive atmosphere on the formation of nanoparticles in the plasma plume induced by nanosecond pulsed laser irradiation of metallic targets at atmospheric pressure and high repetition rate

    Energy Technology Data Exchange (ETDEWEB)

    Girault, M. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Le Garrec, J.-L.; Mitchell, J.B.A. [Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 35042 Rennes Cedex (France); Jouvard, J.-M. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Carvou, E. [Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 35042 Rennes Cedex (France); Menneveux, J.; Yu, J. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Ouf, F.-X. [Institut de Radioprotection et de Sureté Nucléaire IRSN/PSN-RES/SCA/LPMA BP 68, 91192 Gif-Sur-Yvette (France); Carles, S. [Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 35042 Rennes Cedex (France); Potin, V.; Pillon, G.; Bourgeois, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Perez, J. [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex (France); Marco de Lucas, M.C., E-mail: delucas@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); and others

    2016-06-30

    Highlights: • NPs formed in a plasma-plume during laser irradiation of metals (Al, Ti, Ag) were studied. • In situ SAXS and ex situ TEM, XRD and Raman spectra were measured. • NPs size decreased when increasing the O{sub 2} fraction in a controlled O{sub 2}+N{sub 2} atmosphere. • The oxidation of metal NPs in the plasma restricts the increase of the size of the NPs. - Abstract: The influence of a reactive atmosphere on the formation of nanoparticles (NPs) in the plasma plume generated by nanosecond pulsed laser irradiation of metal targets (Ti, Al, Ag) was probed in situ using Small Angle X-ray Scattering (SAXS). Air and different O{sub 2}–N{sub 2} gas mixtures were used as reactive gas within atmospheric pressure. SAXS results showed the formation of NPs in the plasma-plume with a mean radius varying in the 2–5 nm range. A decrease of the NPs size with increasing the O{sub 2} percentage in the O{sub 2}–N{sub 2} gas mixture was also showed. Ex situ observations by transmission electron microscopy and structural characterizations by X-ray diffraction and Raman spectroscopy were also performed for powders collected in experiments done using air as ambient gas. The stability of the different metal oxides is discussed as being a key parameter influencing the formation of NPs in the plasma-plume.

  19. Transmembrane TNF-alpha reverse signaling leading to TGF-beta production is selectively activated by TNF targeting molecules: Therapeutic implications.

    Science.gov (United States)

    Szondy, Zsuzsa; Pallai, Anna

    2017-01-01

    Tumor necrosis factor (TNF)-α is a potent pro-inflammatory cytokine exerting pleiotropic effects on various cell types. It is synthesized in a precursor form called transmembrane TNF-α (mTNF-α) which, after being processed by metalloproteinases, is released in a soluble form to mediate its biological activities through Type 1 and 2 TNF receptors in TNF receptor expressing cells. In addition to acting in soluble form, TNF-α also acts in the transmembrane form both as a ligand by activating TNF receptors, as well as a receptor that transmits outside-to-inside (reverse) signals back into mTNF-α bearing cells. Since the discovery that TNF-α plays a determining role in the pathogenesis of several chronic inflammatory diseases, anti-TNF agents are increasingly being used in the treatment of a rapidly expanding number of rheumatic and systemic autoimmune diseases, such as rheumatoid arthritis, Crohn's disease, psoriasis, psoriatic arthritis, ankyloting spondylitis, Wegener granulomatosis and sarcoidosis. There are 5 TNF antagonists currently available: etanercept, a soluble TNF receptor construct; infliximab, a chimeric monoclonal antibody; adalimumab and golimumab, fully human antibodies; and certolizumab pegol, an Fab' fragment of a humanized anti-TNF-α antibody. Though each compound can efficiently neutralize TNF-α, increasing evidence suggests that they show different efficacy in the treatment of these diseases. These observations indicate that in addition to neutralizing TNF-α, other biological effects induced by TNF-α targeting molecules dictate the success of the therapy. Recently, we found that mTNF-α reverse signaling leads to transforming growth factor (TGF)-β production in macrophages and anti-TNF agents selectively trigger this pathway. In this review we will focus on the potential contribution of the activation of the mTNF-α signaling pathway to the success of the anti-TNF therapy.

  20. Investigation of beam window buckling with consideration of irradiation effects for conceptual ADS design

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, Takanori, E-mail: sugawara.takanori@jaea.go.j [Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai-mura, Naka-gun, Ibaraki, 319-1195 (Japan); Kikuchi, Kenji; Nishihara, Kenji; Oigawa, Hiroyuki [Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai-mura, Naka-gun, Ibaraki, 319-1195 (Japan)

    2010-03-15

    The investigation of the beam window, which is a key component in the conceptual design of an Accelerator Driven System, has been performed. In the past studies, it was found that buckling failure due to hydrostatic pressure in the liquid lead bismuth was critical failure mode for the beam window and detailed structural analyses were performed. These investigations, however, did not consider irradiation effects by neutrons and protons. In this study, investigations based on the latest knowledge for irradiation effects obtained in the spallation target irradiation program are presented. By using the experimental data, it was found that the buckling pressure increased about 80% by the irradiation (20 dpa). It was assumed that if the beam window had integrity in the unirradiated condition, the buckling failure would not be critical issue during the ADS operation.

  1. Influence of the reactive atmosphere on the formation of nanoparticles in the plasma plume induced by nanosecond pulsed laser irradiation of metallic targets at atmospheric pressure and high repetition rate

    Science.gov (United States)

    Girault, M.; Le Garrec, J.-L.; Mitchell, J. B. A.; Jouvard, J.-M.; Carvou, E.; Menneveux, J.; Yu, J.; Ouf, F.-X.; Carles, S.; Potin, V.; Pillon, G.; Bourgeois, S.; Perez, J.; Marco de Lucas, M. C.; Lavisse, L.

    2016-06-01

    The influence of a reactive atmosphere on the formation of nanoparticles (NPs) in the plasma plume generated by nanosecond pulsed laser irradiation of metal targets (Ti, Al, Ag) was probed in situ using Small Angle X-ray Scattering (SAXS). Air and different O2-N2 gas mixtures were used as reactive gas within atmospheric pressure. SAXS results showed the formation of NPs in the plasma-plume with a mean radius varying in the 2-5 nm range. A decrease of the NPs size with increasing the O2 percentage in the O2-N2 gas mixture was also showed. Ex situ observations by transmission electron microscopy and structural characterizations by X-ray diffraction and Raman spectroscopy were also performed for powders collected in experiments done using air as ambient gas. The stability of the different metal oxides is discussed as being a key parameter influencing the formation of NPs in the plasma-plume.

  2. Separation of no-carrier-added {sup 203}Pb, a surrogate radioisotope, from proton irradiated {sup nat}Tl{sub 2}CO{sub 3} target using calcium alginate hydrogel beads

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Kangkana; Sen, Kamalika [Univ. of Calcutta, Kolkata (India). Dept. of Chemistry; Lahiri, Susanta [Saha Institute of Nuclear Physics, Kolkata (India)

    2016-07-01

    {sup 203}Pb is a promising radioisotope in the field of medical science as an imaging surrogate of {sup 212}Pb. In the present investigation {sup 203}Pb was produced by proton irradiation of natural Tl{sub 2}CO{sub 3} target and was separated from the bulk Tl target using calcium alginate (CA) hydrogel beads with a high separation factor (3.8 x 10{sup 4} at 10{sup -3} M HNO{sub 3}). During the separation process {sup 203}Pb was encapsulated in CA beads and desorption of the radioisotope could only be achieved in 1M HNO{sub 3}. Possibility of Tl uptake was also checked in Fe doped CA (Fe-CA) beads after oxidation of Tl(I) to Tl(III) by sodium bismuthate. No significant uptake of Tl(III) was noticed in the Fe-CA beads. The matrix is therefore suitable for isolation of {sup 203}Pb from the target as well as its storage in the bead for therapeutic as well as diagnostic purpose.

  3. Niobium sputtered Havar foils for the high-power production of reactive [{sup 18}F]fluoride by proton irradiation of [{sup 18}O]H{sub 2}O targets

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, J.S. [Edmonton PET Centre, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, T6G 1Z2 (Canada)], E-mail: johnwils@cancerboard.ab.ca; Avila-Rodriguez, M.A. [Edmonton PET Centre, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, T6G 1Z2 (Canada); Johnson, R.R.; Zyuzin, A. [Advanced Cyclotron Systems Inc., 7851 Alderbridge Way, Richmond, BC, V6X 2A4 (Canada); McQuarrie, S.A. [Edmonton PET Centre, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, T6G 1Z2 (Canada)

    2008-05-15

    Niobium sputtered Havar entrance foils were used for the production of reactive [{sup 18}F]fluoride by proton irradiation of [{sup 18}O]H{sub 2}O targets under pressurized conditions. The synthesis yield in the routine production of 2-[{sup 18}F]fluoro-2-deoxy-glucose (FDG) was used as an indicative parameter of the reactivity of {sup 18}F. The yield of FDG obtained with {sup 18}F produced in a target with Havar foil was used as a baseline. No statistically significant difference was found in the saturated yields of {sup 18}F when using Havar or Havar-Nb sputtered entrance foils. However, the amount of long-lived radionuclidic impurities decreased more than 10-fold using the Havar-Nb entrance foil. The average decay corrected synthesis yield of FDG, evaluated over a period of more than 2 years, was found to be {approx}5% higher when using a Havar-Nb entrance foil and a marked improvement on the FDG yield consistency was noted. In addition, the frequency of target rebuilding was greatly diminished when using the Nb sputtered entrance foil.

  4. fs激光在靶背表面产生的质子束成丝%Filamented proton beams from the rear surface of target irradiated by fs laser

    Institute of Scientific and Technical Information of China (English)

    谷渝秋; 蔡达锋; 郑志坚; 温天舒; 淳于书泰; 陈家斌; 周维民; 焦春晔; 陈豪

    2004-01-01

    介绍了利用3TW/60fs钛宝石超短超强激光与20μm铜薄膜靶相互作用的实验.实验观测到质子束的角分布随激光功率密度有所变化.在较高的功率密度(~1×1018W/cm2)时,观测到环状的质子束分布,发散角较大.在较低的激光功率密度(~2×1017W/cm2)时,质子束发散角减小,质子束出现成丝现象.质子束的角分布实际上反映了从靶前输运到靶背的超热电子电流横向分布.在输运过程中,由于Weibel不稳定性会使超热电子电流出现空心化并最后破裂成丝.%Proton emission patterns from the rear surface of targets irradiated by 60fs laser pulse at different intensity have been studied. The filaments of protons emission from 20μm Cu target were observed in the shots with lower laser intensity (about 2×1017W/cm2). As the laser intensity increased up to about 1×1018W/cm2 for the same target thickness, the filaments of proton beam disappeared and a hollow proton beam emerged. The patterns of proton beams revealed the traverse distribution of hot electrons reached the rear surface of target after a long distance transportation from the front surface of target. In this process, Weibel instability will drive electron beam into hollow structure and break into filaments in the end.

  5. Irradiation damage studies of high power accelerator materials

    Energy Technology Data Exchange (ETDEWEB)

    Simos, N. [Brookhaven National Laboratory, Upton, NY 11973 (United States)], E-mail: simos@bnl.gov; Kirk, H.G.; Thieberger, P.; Ludewig, H.; Conor, J.O.; Mausner, L. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Trung, P.-T. [SUNY Stony Brook, Stony Brook, NY 11794 (United States); McDonald, K.T. [Princeton University, Princeton, NJ 08544 (United States); Yoshimura, K. [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Bennett, J.R.J. [Rutherford Appleton Laboratory, CCLRC, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

    2008-06-30

    High-performance production targets and other critical accelerator components intercepting intense, energetic proton beams are essential as the accelerator community envisions the next generation, multi-MW accelerators. Materials that have served the nuclear sector well may not be suitable to play such a role which demands that the material comprising the beam-intercepting element must, in addition to the long exposure which leads to accumulated irradiation damage, also endure short exposure that manifests itself as thermo-mechanical shock. The ability of materials to resist irradiation-induced degradation of its properties that control shock and fatigue is of primary interest. The need for such materials that extend beyond resistance to the neutron-driven irradiation damage of reactor components has led to an extensive search and experimentation with new alloys and composites. These new high-performance materials, which appear to possess the right combination of mechanical and physical properties, are explored through a multi-phased experimental study at Brookhaven National Laboratory (BNL). This study, which brings together the interest in accelerator targets of different facilities around the world, seeks to simulate conditions of both short and long exposure to proton beams to assess the survivability potential of these new alloys and composite materials. While thermo-mechanical shock effects have been studied in the early stages of this comprehensive effort, it is irradiation damage that is currently the focus of the study and results to-date are presented in this paper along with the status and objectives of on-going studies. Of special interest are results depicting damage reversal through post-irradiation annealing in some of the materials. High fluences of 200 and/or 117 MeV protons provided by the BNL Linac beam that serves the Isotope Production Facility were used to assess irradiation damage in these new composites and alloys.

  6. FY 2013 Summary Report: Post-Irradiation Examination of Zircaloy-4 Samples in Target Capsules and Initiation of Bending Fatigue Testing for Used Nuclear Fuel Vibration Integrity Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Richard H [ORNL; Yan, Yong [ORNL; Wang, Jy-An John [ORNL; Ott, Larry J [ORNL; Howard, Rob L [ORNL

    2013-10-01

    This report documents ongoing work performed at Oak Ridge National Laboratory (ORNL) for the Department of Energy, Office of Fuel Cycle Technology Used Fuel Disposition Campaign (UFDC), and satisfies the deliverable for milestone M2FT-13OR0805041, “Data Report on Hydrogen Doping and Irradiation in HFIR.” This work is conducted under WBS 1.02.08.05, Work Package FT-13OR080504 ST “Storage and Transportation-Experiments – ORNL.” The objectives of work packages that make up the S&T Experiments Control Account are to conduct the separate effects tests (SET) and small-scale tests that have been identified in the Used Nuclear Fuel Storage and Transportation Data Gap Prioritization (FCRD-USED-2012-000109). In FY 2013, the R&D focused on cladding and container issues and small-scale tests as identified in Sections A-2.9 and A-2.12 of the prioritization report.

  7. Status of Post Irradiation Examination of FCAB and FCAT Irradiation Capsules

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD)

    2016-09-29

    A series of irradiation programs are ongoing to address the need for determining the radiation tolerance of FeCrAl alloys. These irradiation programs, deemed the FCAT and FCAB irradiation programs, use the High Flux Isotope Reactor (HFIR) to irradiate second generation wrought FeCrAl alloys and early-generation powder-metallurgy (PM) oxide dispersion-strengthened (ODS) FeCrAl alloys. Irradiations have been or are being performed at temperatures of 200°C, 330°C, and 550°C from doses of 1.8 dpa up to 16 dpa. Preliminary post-irradiation examination (PIE) on low dose (<2 dpa) irradiation capsules of tensile specimens has been performed. Analysis of co-irradiated SiC thermometry have shown reasonable matching between the nominal irradiation temperatures and the target irradiation temperatures. Room temperature tensile tests have shown typical radiation-induced hardening and embrittlement at irradiations of 200°C and 330°C, but a propensity for softening when irradiated to 550°C for the wrought alloys. The PM-ODS FeCrAl specimens showed less hardening compared to the wrought alloys. Future PIE includes high temperature tensile tests on the low dose irradiation capsules as well as the determination of reference fracture toughness transition temperature, To, in alloys irradiated to 7 dpa and higher.

  8. Status of Post Irradiation Examination of FCAB and FCAT Irradiation Capsules

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD)

    2016-09-29

    A series of irradiation programs are ongoing to address the need for determining the radiation tolerance of FeCrAl alloys. These irradiation programs, deemed the FCAT and FCAB irradiation programs, use the High Flux Isotope Reactor (HFIR) to irradiate second generation wrought FeCrAl alloys and early generation powder-metallurgy (PM) oxide dispersion strengthened (ODS) FeCrAl alloys. Irradiations have been or are being performed at temperatures of 200°C, 330°C, and 550°C from doses of 1.8 dpa up to 16 dpa. Preliminary post-irradiation examination (PIE) on low dose (<2 dpa) irradiation capsules of tensile specimens has been performed. Analysis of co-irradiated SiC thermometry have shown reasonable matching between the nominal irradiation temperatures and the target irradiation temperatures. Room temperature tensile tests have shown typical radiation-induced hardening and embrittlement at irradiations of 200°C and 330°C but a propensity for softening when irradiated to 550°C for the wrought alloys. The PM-ODS FeCrAl specimens showed less hardening compared to the wrought alloys. Future PIE includes high temperature tensile tests on the low dose irradiation capsules as well as the determination of reference fracture toughness transition temperature, To, in alloys irradiated to 7 dpa and higher.

  9. Proton irradiation of simple gas mixtures: Influence of irradiation parameters

    Science.gov (United States)

    Sack, Norbert J.; Schuster, R.; Hofmann, A.

    1990-01-01

    In order to get information about the influence of irradiation parameters on radiolysis processes of astrophysical interest, methane gas targets were irradiated with 6.5 MeV protons at a pressure of 1 bar and room temperature. Yields of higher hydrocarbons like ethane or propane were found by analysis of irradiated gas samples using gas chromatography. The handling of the proton beam was of great experimental importance for determining the irradiation parameters. In a series of experiments current density of the proton beam and total absorbed energy were shown to have a large influence on the yields of produced hydrocarbons. Mechanistic interpretations of the results are given and conclusions are drawn with regard to the chemistry and the simulation of various astrophysical systems.

  10. Study of Rayleigh–Taylor growth in laser irradiated planar SiO{sub 2} targets at ignition-relevant conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hager, J. D.; Collins, T. J. B.; Knauer, J. P.; Meyerhofer, D. D.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Smalyuk, V. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2013-07-15

    Rayleigh–Taylor (RT) growth experiments were performed on the OMEGA laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] using planar SiO{sub 2} targets seeded with a single mode 60-μm wavelength perturbation driven at peak laser intensities up to 9 × 10{sup 14} W/cm{sup 2}. These are the first RT measurements in SiO{sub 2} at conditions relevant to direct-drive inertial confinement fusion ignition. The measured average modulation growth rates agree with the 2-D hydrodynamics code DRACO, providing an important step in the development of target ablators that are robust to RT growth and hot- electron preheat considerations when driven at the intensities required to achieve thermonuclear ignition.

  11. Synthesis of surface molecular imprinted TiO2/graphene photocatalyst and its highly efficient photocatalytic degradation of target pollutant under visible light irradiation

    Science.gov (United States)

    Lai, Cui; Wang, Man-Man; Zeng, Guang-Ming; Liu, Yun-Guo; Huang, Dan-Lian; Zhang, Chen; Wang, Rong-Zhong; Xu, Piao; Cheng, Min; Huang, Chao; Wu, Hai-Peng; Qin, Lei

    2016-12-01

    The molecular imprinted TiO2/graphene photocatalyst (MIP-TiO2/GR) was successfully prepared with bisphenol A (BPA) as the template molecule (target pollutant) and o-phenylenediamine (OPDA) as functional monomers by the surface molecular imprinting method. The combination between BPA and OPDA led to the formation of the precursor, and the subsequent polymerization of OPDA initiated by ultraviolet radiation can ensure the realization of MIP-TiO2/GR. The samples were characterized by SEM, EDS, XRD, BET, UV-vis DRS and Zeta potential. In addition, adsorption capacities, adsorption selectivity and visible light photocatalytic performances of MIP-TiO2/GR and non-imprinted TiO2/graphene (NIP-TiO2/GR) were evaluated. Moreover, the effects of pH and initial BPA concentration on removal efficiency of BPA were also investigated. The results showed that MIP-TiO2/GR exhibited better adsorption capacity and adsorption selectivity towards the template molecule compared to NIP-TiO2/GR due to the imprinted cavities on the surface of MIP-TiO2/GR. Moreover, the photocatalytic activity of MIP-TiO2/GR toward the target molecules was stronger than that of NIP-TiO2/GR as a result of large adsorption capacity to target molecules and narrow band gap energy on MIP-TiO2/GR. Therefore, modifying the photocatalyst by the surface molecular imprinting is a promising method to improve the molecule recognition and photocatalytic efficiency of photocatalyst for target pollutant.

  12. Phytosanitary irradiation - Development and application

    Science.gov (United States)

    Hallman, Guy J.; Loaharanu, Paisan

    2016-12-01

    Phytosanitary irradiation, the use of ionizing radiation to disinfest traded agricultural commodities of regulated pests, is a growing use of food irradiation that has great continued potential for increase in commercial application. In 2015 approximately 25,000 t of fresh fruits and vegetables were irradiated globally for phytosanitary purposes. Phytosanitary irradiation has resulted in a paradigm shift in phytosanitation in that the final burden of proof of efficacy of the treatment has shifted from no live pests upon inspection at a port of entry (as for all previous phytosanitary treatments) to total dependence on certification that the treatment for target pests is based on adequate science and is commercially conducted and protected from post-treatment infestation. In this regard phytosanitary irradiation is managed more like a hazard analysis and critical control point (HACCP) approach more consistent with food safety than phytosanitation. Thus, phytosanitary irradiation offers a more complete and rigorous methodology for safeguarding than other phytosanitary measures. The role of different organizations in achieving commercial application of phytosanitary irradiation is discussed as well as future issues and applications, including new generic doses.

  13. Gas production in the MEGAPIE spallation target

    Energy Technology Data Exchange (ETDEWEB)

    Thiolliere, N. [SUBATECH, EMN-IN2P3/CNRS-Universite, Nantes, F-44307 (France); Zanini, L. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); David, J. C. [CEA Saclay, Irfu/SPhN, 91191 Gif Sur Yvette (France); Eikenberg, J. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Guertin, A. [SUBATECH, EMN-IN2P3/CNRS-Universite, Nantes, F-44307 (France); Konobeyev, A. Y. [Institut fuer Reaktorsicherheit, FZK GmbH, 76021 Karlsruhe (Germany); Lemaire, S. [CEA Bruyeres-le-Chatel, DAM Ile de France, 91297 Arpajon Cedex (France); Panebianco, S. [CEA Saclay, Irfu/SPhN, 91191 Gif Sur Yvette (France)

    2011-07-01

    The Megawatt Pilot Experiment (MEGAPIE) project was started in 2000 to design, build and operate a liquid Lead-Bismuth Eutectic (LBE) spallation neutron target at the power level of 1 MW. The target was irradiated for four months in 2006 at the Paul Scherrer Inst. in Switzerland. Gas samples were extracted in various phases of operation and analyzed by {gamma} spectroscopy leading to the determination of the main radioactive isotopes released from the LBE. Comparison with calculations performed using several validated codes (MCNPX2.5.0/CINDER'90, FLUKA/ORIHET and SNT) yields the ratio between simulated in-target isotope production rates and experimental amount released at any given time. This work underlines the weak points of spallation models for some released isotopes. Also, results provide relevant information for safety and radioprotection in an Accelerator Driven System (ADS) and more particularly for the gas management in a spallation target dedicated to neutron production facilities. (authors)

  14. Vacuolar targeting of r-proteins in sugarcane leads to higher levels of purifiable commercially equivalent recombinant proteins in cane juice.

    Science.gov (United States)

    Palaniswamy, Harunipriya; Syamaladevi, Divya P; Mohan, Chakravarthi; Philip, Anna; Petchiyappan, Anushya; Narayanan, Subramonian

    2016-02-01

    Sugarcane is an ideal candidate for biofarming applications because of its large biomass, rapid growth rate, efficient carbon fixation pathway and a well-developed storage tissue system. Vacuoles occupy a large proportion of the storage parenchyma cells in the sugarcane stem, and the stored products can be harvested as juice by crushing the cane. Hence, for the production of any high-value protein, it could be targeted to the lytic vacuoles so as to extract and purify the protein of interest from the juice. There is no consensus vacuolar-targeting sequence so far to target any heterologous proteins to sugarcane vacuole. Hence, in this study, we identified an N-terminal 78-bp-long putative vacuolar-targeting sequence from the N-terminal domain of unknown function (DUF) in Triticum aestivum 6-SFT (sucrose: fructan 6-fructosyl transferase). In this study, we have generated sugarcane transgenics with gene coding for the green fluorescent protein (GFP) fused with the vacuolar-targeting determinants at the N-terminal driven by a strong constitutive promoter (Port ubi882) and demonstrated the targeting of GFP to the vacuoles. In addition, we have also generated transgenics with His-tagged β-glucuronidase (GUS) and aprotinin targeted to the lytic vacuole, and these two proteins were isolated and purified from the transgenic sugarcane and compared with commercially available protein samples. Our studies have demonstrated that the novel vacuolar-targeting determinant could localize recombinant proteins (r-proteins) to the vacuole in high concentrations and such targeted r-proteins can be purified from the juice with a few simple steps.

  15. Monte Carlo calculated microdosimetric spread for cell nucleus-sized targets exposed to brachytherapy 125I and 192Ir sources and 60Co cell irradiation.

    Science.gov (United States)

    Villegas, Fernanda; Tilly, Nina; Ahnesjö, Anders

    2013-09-07

    The stochastic nature of ionizing radiation interactions causes a microdosimetric spread in energy depositions for cell or cell nucleus-sized volumes. The magnitude of the spread may be a confounding factor in dose response analysis. The aim of this work is to give values for the microdosimetric spread for a range of doses imparted by (125)I and (192)Ir brachytherapy radionuclides, and for a (60)Co source. An upgraded version of the Monte Carlo code PENELOPE was used to obtain frequency distributions of specific energy for each of these radiation qualities and for four different cell nucleus-sized volumes. The results demonstrate that the magnitude of the microdosimetric spread increases when the target size decreases or when the energy of the radiation quality is reduced. Frequency distributions calculated according to the formalism of Kellerer and Chmelevsky using full convolution of the Monte Carlo calculated single track frequency distributions confirm that at doses exceeding 0.08 Gy for (125)I, 0.1 Gy for (192)Ir, and 0.2 Gy for (60)Co, the resulting distribution can be accurately approximated with a normal distribution. A parameterization of the width of the distribution as a function of dose and target volume of interest is presented as a convenient form for the use in response modelling or similar contexts.

  16. Total lymphoid irradiation in the Wistar rat: technique and dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hoogenhout, J.; Kazem, I.; de Jong, J.

    1983-01-01

    The technical and dosimetric aspects of total lymphoid irradiation (TLI) in the Wistar rat were evaluated as part of a set-up to develop a new model for tumor xenotransplantation. Information obtained from anatomical dissections, radionuclide imaging of the spleen, lymphography and chromolymphography was used to standardize the localization portals cut out in a lead plate. The two portals encompassed the lymphoid tissue above and below the diaphragm. A specially designed masonite phantom was used to measure the dose distribution in the simulated target volumes. Ionization chamber dosimetery, thermoluminescence dosimetry and film densitometry were used for measuring exposure and absorbed dose. Irradiation was performed with 250 kV X rays (HVL 3.1 mm Cu). The dose rate was regulated by adjusting the treatment distance. The dose inhomogeneity measured in the target volumes varied between 80-100%. The side scatter dose to non target tissues under the shielded area between the two portals ranged between 20-30%. The technique and dosimetry of total lymphoid irradiation in Wistar rats are now standardized and validated and pave the way for tumor xenotransplantation experiments.

  17. Mapping the genome of Plasmodium falciparum on the drug-like chemical space reveals novel anti-malarial targets and potential drug leads

    DEFF Research Database (Denmark)

    Jensen, Kasper; Plichta, Damian Rafal; Panagiotou, Gianni;

    2012-01-01

    The parasite Plasmodium falciparum is the main agent responsible for malaria. In this study, we exploited a recently published chemical library from GlaxoSmithKline (GSK) that had previously been confirmed to inhibit parasite growth of the wild type (3D7) and the multi-drug resistance (D2d) strains......, in order to uncover the weak links in the proteome of the parasite. We predicted 293 proteins of P. falciparum, including the six out of the seven verified targets for P. falciparum malaria treatment, as targets of 4645 GSK active compounds. Furthermore, we prioritized druggable targets, based on a number...... on integration of available chemical-protein and protein-protein interaction data. Our work suggests that a large number of the P. falciparum proteome is potentially druggable and could therefore serve as novel drug targets in the fight against malaria. At the same time, prioritized compounds from the GSK...

  18. Lack of dystrophin leads to the selective loss of superior cervical ganglion neurons projecting to muscular targets in genetically dystrophic mdx mice.

    Science.gov (United States)

    De Stefano, M Egle; Leone, Lucia; Lombardi, Loredana; Paggi, Paola

    2005-12-01

    Autonomic imbalance is a pathological aspect of Duchenne muscular dystrophy. Here, we show that the sympathetic superior cervical ganglion (SCG) of mdx mice, which lack dystrophin (Dp427), has 36% fewer neurons than that of wild-type animals. Cell loss occurs around P10 and affects those neurons innervating muscular targets (heart and iris), which, differently from the submandibular gland (non-muscular target), are precociously damaged by the lack of Dp427. In addition, although we reveal altered axonal defasciculation in the submandibular gland and reduced terminal sprouting in all SCG target organs, poor adrenergic innervation is observed only in the heart and iris. These alterations, detected as early as P5, when neuronal loss has not yet occurred, suggest that in mdx mice the absence of Dp427 directly impairs the axonal growth and terminal sprouting of sympathetic neurons. However, when these intrinsic alterations combine with structural and/or functional damages of muscular targets, neuronal death occurs.

  19. Targeted deletion of a high-affinity GATA-binding site in the GATA-1 promoter leads to selective loss of the eosinophil lineage in vivo

    National Research Council Canada - National Science Library

    Yu, Channing; Cantor, Alan B; Yang, Haidi; Browne, Carol; Wells, Richard A; Fujiwara, Yuko; Orkin, Stuart H

    2002-01-01

    .... Here we demonstrate that deletion of a high-affinity GATA-binding site in the GATA-1 promoter, an element presumed to mediate positive autoregulation of GATA-1 expression, leads to selective loss...

  20. Gas generation during waste treatment of acidic solutions from the dissolution of irradiated LEU targets for 99Mo production

    Energy Technology Data Exchange (ETDEWEB)

    Bakel, Allen J. [Argonne National Lab. (ANL), Argonne, IL (United States); Conner, Cliff [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-01-01

    The goal of the Reduced Enrichment for Research and Test Reactors Program is to limit the use of high-enriched uranium (HEU) in research and test reactors by substituting low-enriched uranium (LEU) wherever possible. The work reported here documents our work to develop the calcining technologies and processes that will be needed for 99Mo production using LEU foil targets and the Modified Cintichem Process. The primary concern with the conversion to LEU from HEU targets is that it would result in a five- to six-fold increase in the total uranium. This increase results in more liquid waste from the process. We have been working to minimize the increase in liquid waste and to minimize the impact of any change in liquid waste. Direct calcination of uranium-rich nitric acid solutions generates NO2 gas and UO3 solid. We have proposed two processes for treating the liquid waste from a Modified Cintichem Process with a LEU foil. One is an optimized direct calcination process that is similar to the process currently in use. The other is a uranyl oxalate precipitation process. The specific goal of the work reported here was to characterize and compare the chemical reactions that occur during these two processes. In particular, the amounts and compositions of the gaseous and solid products were of interest. A series of experiments was carried out to show the effects of temperature and the redox potential of the reaction atmosphere. The primary products of the direct calcination process were mixtures of U3O8 and UO3 solids and NO2 gas. The primary products of the oxalate precipitation process were mixtures of U3O8 and UO2 solid and CO2 gas. Higher temperature and a reducing atmosphere tended to favor quadrivalent over hexavalent uranium in the solid product. These data will help producers to decide between the two processes. In addition, the data can be used to design

  1. Au-Pt alloy nanoparticles obtained by nanosecond laser irradiation of gold and platinum bulk targets in an ethylene glycol solution

    Science.gov (United States)

    Moniri, Samira; Reza Hantehzadeh, Mohammad; Ghoranneviss, Mahmood; Asadi Asadabad, Mohsen

    2017-07-01

    Au-Pt alloy nanoparticles (NPs) of different compositions ( Au0Pt100 , Au30Pt70 , Au50Pt50 , Au70Pt30 , and Au100Pt0 were obtained using the nanosecond laser ablation of gold and platinum bulk targets in ethylene glycol, followed by mixing highly monodisperse Au and Pt nanocolloids, for the first time. UV-vis absorption spectra of NPs showed that by increasing the Au content in the Au-Pt NPs, the surface plasmon resonance (SPR) peak red-shifted, from 260 to 573nm in a nonlinear way. In addition, the mean crystalline size, crystal structure, d-spacing, and lattice parameters of NPs were estimated from the XRD spectra. Microscopy studies revealed the most NPs have a spherical or near-spherical shape, and the average sizes of Au0Pt100 , Au30Pt70 , Au50Pt50 , Au70Pt30 , and Au100Pt0 NPs were calculated to be 12.50, 14.15, 18.53, 19.29, and 26.38nm, respectively. Also, the chemical identity of the molecules adhering to the NPs surface was considered by Raman and FT-IR spectroscopy techniques. Among different synthesis methods, the demonstrated technique allows easy synthesis of alloy NPs in aqueous media at room temperature with no formation of by-products.

  2. Measurement of the High Energy Neutron Flux on the Surface of the Natural Uranium Target Assembly QUINTA Irradiated by Deuterons of 4 and 8 GeV Energy

    Science.gov (United States)

    Adam, J.; Baldin, A. A.; Chilap, V.; Furman, W.; Katovsky, K.; Khushvaktov, J.; Kumar, V.; Pronskikh, V.; Mar'in, I.; Solnyshkin, A.; Suchopar, M.; Tsupko-Sitnikov, V.; Tyutyunnikov, S.; Vrzalova, J.; Wagner, V.; Zavorka, L.

    Experiments with the natural uranium target assembly "QUINTA" exposed to 4 and 8 GeV deuteron beams of the Nuclotron accelerator at the Joint Institute for Nuclear Research (Dubna) are analyzed. The reaction rates of 27Al(n,y1)24Na, 27Al(n,y2)22Na and 27Al(n,y3)7Be reactions with effective threshold energies of 5, 27, and 119 MeV were measured at both 4 GeV and 8 GeV deuteron beam energies. The average neutron fluxes between the effective threshold energies and the effective ends of the neutron spectra (which are 800 or 1000 MeV for 4 or 8 GeV deuterons) were determined. The evidence for the intensity shift of the neutron spectra to higher neutron energies with the increase of the deuteron energy from 4 GeV to 8 GeV was found from the ratios of the average neutron fluxes. The reaction rates and the average neutron fluxes were calculated with the MCNPX 2.7 code.

  3. Modification of graphene by ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bukowska, Hanna; Akcoeltekin, Sevilay; El Kharrazi, Mourad; Schleberger, Marika [Universitaet Duisburg-Essen, Fakultaet fuer Physik, Duisburg (Germany); Osmani, Orkhan [Universitaet Duisburg-Essen, Fakultaet fuer Physik, Duisburg (Germany); Technische Universitaet Kaiserslautern, Fachbereich Physik, Gottlieb-Daimler-Strasse, Gebaeude 47, 67663 Kaiserslautern (Germany)

    2010-07-01

    Ion irradiation can be used to modify surfaces on the nanometer scale. We investigate graphene on different insulator (SrTiO{sub 3}, TiO{sub 2}, and Al{sub 2}O{sub 3}) and semiconductor (SiO{sub 2}) substrates. The bombardment of those target surfaces with swift heavy ions under grazing angle of incidence creates chains of nanodots on the substrate and folds graphene to typical origami-like structures. The shape of the folded graphene seems to depend on the length of the tracks. The length can be controlled by the angle of incidence. From the analysis of atomic force microscopy measurements, we classify the different types of modifications, with the aim to determine the relationship between chain length and origami shape. Further more we want to develop a theoretical understanding of the physical processes leading to the folding.

  4. Improving intra-fractional target position accuracy using a 3D surface surrogate for left breast irradiation using the respiratory-gated deep-inspiration breath-hold technique.

    Directory of Open Access Journals (Sweden)

    Yi Rong

    Full Text Available PURPOSE: To evaluate the use of 3D optical surface imaging as a surrogate for respiratory gated deep-inspiration breath-hold (DIBH for left breast irradiation. MATERIAL AND METHODS: Patients with left-sided breast cancer treated with lumpectomy or mastectomy were selected as candidates for DIBH treatment for their external beam radiation therapy. Treatment plans were created on both free breathing (FB and DIBH computed tomography (CT simulation scans to determine dosimetric benefits from DIBH. The Real-time Position Management (RPM system was used to acquire patient's breathing trace during DIBH CT acquisition and treatment delivery. The reference 3D surface models from FB and DIBH CT scans were generated and transferred to the "AlignRT" system for patient positioning and real-time treatment monitoring. MV Cine images were acquired during treatment for each beam as quality assurance for intra-fractional position verification. The chest wall excursions measured on these images were used to define the actual target position during treatment, and to investigate the accuracy and reproducibility of RPM and AlignRT. RESULTS: Reduction in heart dose can be achieved using DIBH for left breast/chest wall radiation. RPM was shown to have inferior correlation with the actual target position, as determined by the MV Cine imaging. Therefore, RPM alone may not be an adequate surrogate in defining the breath-hold level. Alternatively, the AlignRT surface imaging demonstrated a superior correlation with the actual target positioning during DIBH. Both the vertical and magnitude real-time deltas (RTDs reported by AlignRT can be used as the gating parameter, with a recommended threshold of ±3 mm and 5 mm, respectively. CONCLUSION: The RPM system alone may not be sufficient for the required level of accuracy in left-sided breast/CW DIBH treatments. The 3D surface imaging can be used to ensure patient setup and monitor inter- and intra- fractional motions

  5. Lead Poisoning

    Science.gov (United States)

    Lead is a metal that occurs naturally in the earth's crust. Lead can be found in all parts of our ... from human activities such as mining and manufacturing. Lead used to be in paint; older houses may ...

  6. Targeting human dendritic cells via DEC-205 using PLGA nanoparticles leads to enhanced cross-presentation of a melanoma-associated antigen

    Directory of Open Access Journals (Sweden)

    Saluja SS

    2014-11-01

    Full Text Available Sandeep S Saluja,1 Douglas J Hanlon,1 Fiona A Sharp,2 Enping Hong,2 David Khalil,1 Eve Robinson,1 Robert Tigelaar,1 Tarek M Fahmy,2,3 Richard L Edelson1 1Department of Dermatology, Yale University School of Medicine, 2Department of Biomedical Engineering, Yale University, 3Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA Abstract: Targeting antigen to dendritic cells (DCs is a powerful and novel strategy for vaccination. Priming or loading DCs with antigen controls whether subsequent immunity will develop and hence whether effective vaccination can be achieved. The goal of our present work was to increase the potency of DC-based antitumor vaccines by overcoming inherent limitations associated with antigen stability and cross-presentation. Nanoparticles prepared from the biodegradable polymer poly(lactic-co-glycolic acid have been extensively used in clinical settings for drug delivery and are currently the subject of intensive investigation as antigen delivery vehicles for vaccine applications. Here we describe a nanoparticulate delivery system with the ability to simultaneously carry a high density of protein-based antigen while displaying a DC targeting ligand on its surface. Utilizing a targeting motif specific for the DC-associated surface ligand DEC-205, we show that targeted nanoparticles encapsulating a MART-127–35 peptide are both internalized and cross-presented with significantly higher efficiency than isotype control-coated nanoparticles in human cells. In addition, the DEC-205-labeled nanoparticles rapidly escape from the DC endosomal compartment and do not colocalize with markers of early (EEA-1 or late endosome/lysosome (LAMP-1. This indicates that encapsulated antigens delivered by nanoparticles may have direct access to the class I cytoplasmic major histocompatibility complex loading machinery, overcoming the need for “classical” cross-presentation and facilitating heightened DC

  7. Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low-Nanomolar Multivalent Ligands.

    Science.gov (United States)

    Wang, Shuai; Dupin, Lucie; Noël, Mathieu; Carroux, Cindy J; Renaud, Louis; Géhin, Thomas; Meyer, Albert; Souteyrand, Eliane; Vasseur, Jean-Jacques; Vergoten, Gérard; Chevolot, Yann; Morvan, François; Vidal, Sébastien

    2016-08-01

    Anti-infectious strategies against pathogen infections can be achieved through antiadhesive strategies by using multivalent ligands of bacterial virulence factors. LecA and LecB are lectins of Pseudomonas aeruginosa implicated in biofilm formation. A series of 27 LecA-targeting glycoclusters have been synthesized. Nine aromatic galactose aglycons were investigated with three different linker arms that connect the central mannopyranoside core. A low-nanomolar (Kd =19 nm, microarray) ligand with a tyrosine-based linker arm could be identified in a structure-activity relationship study. Molecular modeling of the glycoclusters bound to the lectin tetramer was also used to rationalize the binding properties observed.

  8. Attenuation of Telomerase Activity by siRNA Targeted Telomerase RNA Leads to Apoptosis and Inhibition of Proliferation in Human Renal Carcinoma Cells

    Institute of Scientific and Technical Information of China (English)

    Rumin Wen; Junjie Liu; Wang Li; Wenfa Yang; Lijun Mao; Junnian Zheng

    2006-01-01

    OBJECTIVE Telomerase is an attractive molecular target for cancer therapy because the activation of telomerase is one of the key steps in cell immortalization and carcinogenesis. RNA interference using small-interfering RNA (siRNA) has been demonstrated to be an effective method for inhibiting the expression of a given gene in human cells. The aim of the present study was to investigate whether inhibition of telomerase activity by siRNA targeted against human telomerase RNA (hTR) can inhibit proliferation and induce apoptotic cell death in human renal carcinoma cells(HRCCs).METHODS The siRNA duplexes for hTR were synthesized and 786-O HRCCs were transfected with different concentrations of hTR-siRNA. The influence on the hTR mRNA level, telomerase activity, as well as the effect on cell proliferation and apoptosis was examined.RESULTS Anti-hTR siRNA treatment of HRCCs resulted in specific reduction of hTR mRNA and inhibition of telomerase activity. Additionally,significant inhibition of proliferation and induction of apoptosis were observed.CONCLUSION siRNA against the hTR gene can inhibit proliferation and induce apoptosis by blocking telomerase activity of HRCCs. Specific hTR inhibition by siRNA represents a promising new option for renal cancer treatment.

  9. Discovery of a biomarker and lead small molecules to target r(GGGGCC)-associated defects in c9FTD/ALS.

    Science.gov (United States)

    Su, Zhaoming; Zhang, Yongjie; Gendron, Tania F; Bauer, Peter O; Chew, Jeannie; Yang, Wang-Yong; Fostvedt, Erik; Jansen-West, Karen; Belzil, Veronique V; Desaro, Pamela; Johnston, Amelia; Overstreet, Karen; Oh, Seok-Yoon; Todd, Peter K; Berry, James D; Cudkowicz, Merit E; Boeve, Bradley F; Dickson, Dennis; Floeter, Mary Kay; Traynor, Bryan J; Morelli, Claudia; Ratti, Antonia; Silani, Vincenzo; Rademakers, Rosa; Brown, Robert H; Rothstein, Jeffrey D; Boylan, Kevin B; Petrucelli, Leonard; Disney, Matthew D

    2014-09-03

    A repeat expansion in C9ORF72 causes frontotemporal dementia and amyotrophic lateral sclerosis (c9FTD/ALS). RNA of the expanded repeat (r(GGGGCC)exp) forms nuclear foci or undergoes repeat-associated non-ATG (RAN) translation, producing "c9RAN proteins." Since neutralizing r(GGGGCC)exp could inhibit these potentially toxic events, we sought to identify small-molecule binders of r(GGGGCC)exp. Chemical and enzymatic probing of r(GGGGCC)8 indicate that it adopts a hairpin structure in equilibrium with a quadruplex structure. Using this model, bioactive small molecules targeting r(GGGGCC)exp were designed and found to significantly inhibit RAN translation and foci formation in cultured cells expressing r(GGGGCC)66 and neurons transdifferentiated from fibroblasts of repeat expansion carriers. Finally, we show that poly(GP) c9RAN proteins are specifically detected in c9ALS patient cerebrospinal fluid. Our findings highlight r(GGGGCC)exp-binding small molecules as a possible c9FTD/ALS therapeutic and suggest that c9RAN proteins could potentially serve as a pharmacodynamic biomarker to assess efficacy of therapies that target r(GGGGCC)exp.

  10. Studies on the separation of {sup 89}Sr(II) from irradiated yttria target using 4, 4{sup '}(5{sup '}) di-tert-butyl-cyclohexano-18-crown-6 (DtBuCH18C6) by solvent extraction technique

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Debasish; Vithya, Jayagopal; Kumar, Ramalingam; Venkata Subramani, Canchipuram Ramamoorthy; Vasudeva Rao, Polur Ranga [Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam (India). Chemistry Group

    2016-07-01

    The radioisotope {sup 89}Sr as {sup 89}SrCl{sub 2} is medically useful for bone pain palliation and is produced in fast reactors using the {sup 89}Y(n, p){sup 89}Sr reaction. A procedure for isolation of the radionuclide {sup 89}Sr by chemical processing of the irradiated Y{sub 2}O{sub 3} target has been standardised and trial runs have been carried out at the Fast Breeder Test Reactor (FBTR), Kalpakkam. The chemical processing of the irradiated Y{sub 2}O{sub 3} target involves (i) the removal of target Y(III) by TBP extraction and (ii) further purification of the separated {sup 89}Sr fraction by cationic exchange chromatography. However a selective isolation of {sup 89}Sr by the Sr-specific crown ether makes the above chemical processing faster and relatively simple. This work presents a study on the selective removal of Sr from the irradiated target dissolver solution using the Sr-specific crown ether 4,4{sup '}(5{sup '}) di-tert-butyl-cyclohexano-18-crown-6 (DtBuCH18C6) in octanol medium. The separation behaviour of the other impurities such as Ce(IV), Y(III), Tb(III), Eu(III), Zn(II), Mn(II) and Rb(I) present along with Sr(II) in the irradiated sample was also investigated. The method of separation by using the crown ether DtBuCH18C6 is proved to be a potential tool for the purification of {sup 89}Sr(II) source produced from yttria target in fast reactors.

  11. Lead Toxicity

    Science.gov (United States)

    ... including some imported jewelry. What are the health effects of lead? • More commonly, lower levels of lead in children over time may lead to reduced IQ, slow learning, Attention Deficit Hyperactivity Disorder (ADHD), or behavioral issues. • Lead also affects other ...

  12. Timed and targeted differential regulation of nitric oxide synthase (NOS) and anti-NOS genes by reward conditioning leading to long-term memory formation.

    Science.gov (United States)

    Korneev, Sergei A; Straub, Volko; Kemenes, Ildikó; Korneeva, Elena I; Ott, Swidbert R; Benjamin, Paul R; O'Shea, Michael

    2005-02-02

    In a number of neuronal models of learning, signaling by the neurotransmitter nitric oxide (NO), synthesized by the enzyme neuronal NO synthase (nNOS), is essential for the formation of long-term memory (LTM). Using the molluscan model system Lymnaea, we investigate here whether LTM formation is associated with specific changes in the activity of members of the NOS gene family: Lym-nNOS1, Lym-nNOS2, and the antisense RNA-producing pseudogene (anti-NOS). We show that expression of the Lym-nNOS1 gene is transiently upregulated in cerebral ganglia after conditioning. The activation of the gene is precisely timed and occurs at the end of a critical period during which NO is required for memory consolidation. Moreover, we demonstrate that this induction of the Lym-nNOS1 gene is targeted to an identified modulatory neuron called the cerebral giant cell (CGC). This neuron gates the conditioned feeding response and is an essential part of the neural network involved in LTM formation. We also show that the expression of the anti-NOS gene, which functions as a negative regulator of nNOS expression, is downregulated in the CGC by training at 4 h after conditioning, during the critical period of NO requirement. This appears to be the first report of the timed and targeted differential regulation of the activity of a group of related genes involved in the production of a neurotransmitter that is necessary for learning, measured in an identified neuron of known function. We also provide the first example of the behavioral regulation of a pseudogene.

  13. Targeting mixed lineage kinases in ER-positive breast cancer cells leads to G2/M cell cycle arrest and apoptosis.

    Science.gov (United States)

    Wang, Limin; Gallo, Kathleen A; Conrad, Susan E

    2013-08-01

    Estrogen receptor (ER)-positive tumors represent the most common type of breast cancer, and ER-targeted therapies such as antiestrogens and aromatase inhibitors have therefore been widely used in breast cancer treatment. While many patients have benefited from these therapies, both innate and acquired resistance continue to be causes of treatment failure. Novel targeted therapeutics that could be used alone or in combination with endocrine agents to treat resistant tumors or to prevent their development are therefore needed. In this report, we examined the effects of inhibiting mixed-lineage kinase (MLK) activity on ER-positive breast cancer cells and non-tumorigenic mammary epithelial cells. Inhibition of MLK activity with the pan-MLK inhibitor CEP-1347 blocked cell cycle progression in G2 and early M phase, and induced apoptosis in three ER-positive breast cancer cell lines, including one with acquired antiestrogen resistance. In contrast, it had no effect on the cell cycle or apoptosis in two non-tumorigenic mammary epithelial cell lines. CEP-1347 treatment did not decrease the level of active ERK or p38 in any of the cell lines tested. However, it resulted in decreased JNK and NF-κB activity in the breast cancer cell lines. A JNK inhibitor mimicked the effects of CEP-1347 in breast cancer cells, and overexpression of c-Jun rescued CEP-1347-induced Bax expression. These results indicate that proliferation and survival of ER-positive breast cancer cells are highly dependent on MLK activity, and suggest that MLK inhibitors may have therapeutic efficacy for ER-positive breast tumors, including ones that are resistant to current endocrine therapies.

  14. Device performance and lifetime of polymer:fullerene solar cells with UV-ozone-irradiated hole-collecting buffer layers.

    Science.gov (United States)

    Lee, Seungsoo; Nam, Sungho; Lee, Hyena; Kim, Hwajeong; Kim, Youngkyoo

    2011-11-18

    We report the influence of UV-ozone irradiation of the hole-collecting buffer layers on the performance and lifetime of polymer:fullerene solar cells. UV-ozone irradiation was targeted at the surface of the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layers by varying the irradiation time up to 600 s. The change of the surface characteristics in the PEDOT:PSS after UV-ozone irradiation was measured by employing optical absorption spectroscopy, photoelectron yield spectroscopy, and contact angle measurements, while Raman and X-ray photoelectron spectroscopy techniques were introduced for more microscopic analysis. Results showed that the UV-ozone irradiation changed the chemical structure/composition of the surface of the PEDOT:PSS layers leading to the gradual increase of ionization potential with irradiation time in the presence of up-and-down variations in the contact angle (polarity). This surface property change was attributed to the formation of oxidative components, as evidenced by XPS and Auger electron images, which affected the sheet resistance of the PEDOT:PSS layers. Interestingly, device performance was slightly improved by short irradiation (up to 10 s), whereas it was gradually decreased by further irradiation. The short-duration illumination test showed that the lifetime of solar cells with the UV-ozone irradiated PEDOT:PSS layer was improved due to the protective role of the oxidative components formed upon UV-ozone irradiation against the attack of sulfonic acid groups in the PEDOT:PSS layer to the active layer.

  15. Studies of Non-Targeted Effects of Ionising Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Oleg V Belyakov; Heli Mononen; Marjo Peraelae [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland)

    2006-07-01

    The discovery of ionising radiation induced non-targeted effects is important for understanding the dose-response mechanisms relevant to low dose irradiation in vivo. One important question is whether the non-targeted effects relates to a protective mechanism or whether, conversely, it amplifies the number of cells damaged by the isolated radiation tracks of low dose exposures leading to an increased risk of carcinogenesis. One theory supported by the experimental data obtained during this project is that the main functions of the non-targeted effects are to decrease the risk of transformation in a multicellular organism exposed to radiation. Differences in the gene expression profiles, temporal and spatial patterns of key proteins expressed in directly irradiated and bystander cells may determine how the cells ultimately respond to low doses of radiation. Such a mechanism of co-operative response would make the tissue system much more robust. (N.C.)

  16. Irradiation Induced Microstructure Evolution in Nanostructured Materials: A Review.

    Science.gov (United States)

    Liu, Wenbo; Ji, Yanzhou; Tan, Pengkang; Zang, Hang; He, Chaohui; Yun, Di; Zhang, Chi; Yang, Zhigang

    2016-02-06

    Nanostructured (NS) materials may have different irradiation resistance from their coarse-grained (CG) counterparts. In this review, we focus on the effect of grain boundaries (GBs)/interfaces on irradiation induced microstructure evolution and the irradiation tolerance of NS materials under irradiation. The features of void denuded zones (VDZs) and the unusual behavior of void formation near GBs/interfaces in metals due to the interactions between GBs/interfaces and irradiation-produced point defects are systematically reviewed. Some experimental results and calculation results show that NS materials have enhanced irradiation resistance, due to their extremely small grain sizes and large volume fractions of GBs/interfaces, which could absorb and annihilate the mobile defects produced during irradiation. However, there is also literature reporting reduced irradiation resistance or even amorphization of NS materials at a lower irradiation dose compared with their bulk counterparts, since the GBs are also characterized by excess energy (compared to that of single crystal materials) which could provide a shift in the total free energy that will lead to the amorphization process. The competition of these two effects leads to the different irradiation tolerance of NS materials. The irradiation-induced grain growth is dominated by irradiation temperature, dose, ion flux, character of GBs/interface and nanoprecipitates, although the decrease of grain sizes under irradiation is also observed in some experiments.

  17. A human polymorphism affects NEDD4L subcellular targeting by leading to two isoforms that contain or lack a C2 domain

    Directory of Open Access Journals (Sweden)

    Lalouel Jean-Marc

    2009-04-01

    Full Text Available Abstract Background Ubiquitination serves multiple cellular functions, including proteasomal degradation and the control of stability, function, and intracellular localization of a wide variety of proteins. NEDD4L is a member of the HECT class of E3 ubiquitin ligases. A defining feature of NEDD4L protein isoforms is the presence or absence of an amino-terminal C2 domain, a class of subcellular, calcium-dependent targeting domains. We previously identified a common variant in human NEDD4L that generates isoforms that contain or lack a C2 domain. Results To address the potential functional significance of the NEDD4L common variant on NEDD4L subcellular localization, NEDD4L isoforms that either contained or lacked a C2 domain were tagged with enhanced green fluorescent protein, transfected into Xenopus laevis kidney epithelial cells, and imaged by performing confocal microscopy on live cells. We report that the presence or absence of this C2 domain exerts differential effects on the subcellular distribution of NEDD4L, the ability of C2 containing and lacking NEDD4L isoforms to mobilize in response to a calcium stimulus, and the intracellular transport of subunits of the NEDD4L substrate, ENaC. Furthermore, the ability of the C2-containing isoform to influence β-ENaC mobilization from intracellular pools involves the NEDD4L active site for ubiquitination. We propose a model to account for the potential impact of this common genetic variant on protein function at the cellular level. Conclusion NEDD4L isoforms that contain or lack a C2 domain target different intracellular locations. Additionally, whereas the C2-containing NEDD4L isoform is capable of shuttling between the plasma membrane and intracellular compartments in response to calcium stimulus the C2-lacking isoform can not. The C2-containing isoform differentially affects the mobilization of ENaC subunits from intracellular pools and this trafficking step requires NEDD4L ubiquitin ligase

  18. HAMS: High-Affinity Mass Spectrometry Screening. A High-Throughput Screening Method for Identifying the Tightest-Binding Lead Compounds for Target Proteins with No False Positive Identifications

    Science.gov (United States)

    Imaduwage, Kasun P.; Go, Eden P.; Zhu, Zhikai; Desaire, Heather

    2016-09-01

    A major challenge in drug discovery is the identification of high affinity lead compounds that bind a particular target protein; these leads are typically identified by high throughput screens. Mass spectrometry has become a detection method of choice in drug screening assays because the target and the ligand need not be modified. Label-free assays are advantageous because they can be developed more rapidly than assays requiring labels, and they eliminate the risk of the label interfering with the binding event. However, in commonly used MS-based screening methods, detection of false positives is a major challenge. Here, we describe a detection strategy designed to eliminate false positives. In this approach, the protein and the ligands are incubated together, and the non-binders are separated for detection. Hits (protein binders) are not detectable by MS after incubation with the protein, but readily identifiable by MS when the target protein is not present in the incubation media. The assay was demonstrated using three different proteins and hundreds of non-inhibitors; no false positive hits were identified in any experiment. The assay can be tuned to select for ligands of a particular binding affinity by varying the quantity of protein used and the immobilization method. As examples, the method selectively detected inhibitors that have Ki values of 0.2 μM, 50 pM, and 700 pM. These findings demonstrate that the approach described here compares favorably with traditional MS-based screening methods.

  19. HAMS: High-Affinity Mass Spectrometry Screening. A High-Throughput Screening Method for Identifying the Tightest-Binding Lead Compounds for Target Proteins with No False Positive Identifications

    Science.gov (United States)

    Imaduwage, Kasun P.; Go, Eden P.; Zhu, Zhikai; Desaire, Heather

    2016-11-01

    A major challenge in drug discovery is the identification of high affinity lead compounds that bind a particular target protein; these leads are typically identified by high throughput screens. Mass spectrometry has become a detection method of choice in drug screening assays because the target and the ligand need not be modified. Label-free assays are advantageous because they can be developed more rapidly than assays requiring labels, and they eliminate the risk of the label interfering with the binding event. However, in commonly used MS-based screening methods, detection of false positives is a major challenge. Here, we describe a detection strategy designed to eliminate false positives. In this approach, the protein and the ligands are incubated together, and the non-binders are separated for detection. Hits (protein binders) are not detectable by MS after incubation with the protein, but readily identifiable by MS when the target protein is not present in the incubation media. The assay was demonstrated using three different proteins and hundreds of non-inhibitors; no false positive hits were identified in any experiment. The assay can be tuned to select for ligands of a particular binding affinity by varying the quantity of protein used and the immobilization method. As examples, the method selectively detected inhibitors that have Ki values of 0.2 μM, 50 pM, and 700 pM. These findings demonstrate that the approach described here compares favorably with traditional MS-based screening methods.

  20. Radiation-Induced Epigenetic Alterations after Low and High LET Irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Aypar, Umut; Morgan, William F.; Baulch, Janet E.

    2011-02-01

    Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding the delayed, non-targeted effects of radiation including radiationinduced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET x-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. MiRNA shown to be altered in expression level after x-ray irradiation are involved in chromatin remodeling and DNA methylation. Different and higher incidence of epigenetic changes were observed after exposure to low LET x-rays than high LET Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This study also shows that the irradiated cells acquire epigenetic changes even though they are chromosomally stable suggesting that epigenetic aberrations may arise in the cell without initiating RIGI.

  1. Oncogenic ras-driven cancer cell vesiculation leads to emission of double-stranded DNA capable of interacting with target cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Tae Hoon; Chennakrishnaiah, Shilpa [Montreal Children’s Hospital, Research Institute of McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Audemard, Eric [McGill University and Genome Quebec Innovation Centre, Montreal, Quebec (Canada); Montermini, Laura; Meehan, Brian [Montreal Children’s Hospital, Research Institute of McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Rak, Janusz, E-mail: janusz.rak@mcgill.ca [Montreal Children’s Hospital, Research Institute of McGill University Health Centre, McGill University, Montreal, Quebec (Canada)

    2014-08-22

    Highlights: • Oncogenic H-ras stimulates emission of extracellular vesicles containing double-stranded DNA. • Vesicle-associated extracellular DNA contains mutant N-ras sequences. • Vesicles mediate intercellular transfer of mutant H-ras DNA to normal fibroblasts where it remains for several weeks. • Fibroblasts exposed to vesicles containing H-ras DNA exhibit increased proliferation. - Abstract: Cell free DNA is often regarded as a source of genetic cancer biomarkers, but the related mechanisms of DNA release, composition and biological activity remain unclear. Here we show that rat epithelial cell transformation by the human H-ras oncogene leads to an increase in production of small, exosomal-like extracellular vesicles by viable cancer cells. These EVs contain chromatin-associated double-stranded DNA fragments covering the entire host genome, including full-length H-ras. Oncogenic N-ras and SV40LT sequences were also found in EVs emitted from spontaneous mouse brain tumor cells. Disruption of acidic sphingomyelinase and the p53/Rb pathway did not block emission of EV-related oncogenic DNA. Exposure of non-transformed RAT-1 cells to EVs containing mutant H-ras DNA led to the uptake and retention of this material for an extended (30 days) but transient period of time, and stimulated cell proliferation. Thus, our study suggests that H-ras-mediated transformation stimulates vesicular emission of this histone-bound oncogene, which may interact with non-transformed cells.

  2. Lead Poisoning

    Science.gov (United States)

    ... lead is of microscopic size, invisible to the naked eye. More often than not, children with elevated ... majority of the childhood lead poisoning cases we see today. Children and adults too can get seriously ...

  3. Stereotactic Irradiation of Lung Cancer

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To investigate the best stereotactic irradiation (STI) technique in treatment of small lung tumors, using dose-volume statistics. Methods: Dose-volume histogram (DVH) of the study phantom consisting of CT using the software of FOCUS-3D planning system. The beam was a 6MV X-ray from a Varian 2300C. The analysis data of Dose-volume statistics was from the technique used for: (1) 2- 12 arcs; (2) 20° - 45° separation angle of arcs; (3) 80° - 160° of gantry rotation. Then we studied the difference of DVH with various irradiation techniques and the influence of target positions and field size by calculated to the distribution of dose from 20%- 90% of the six targets in the lung with 3×3 cm2, 4′ 4 cm2 and 5′ 5 cm2 field size. Results: The volume irradiated pulmonary tissue was the smallest using a six non-coplanar 120° arcs with 30° separation between arcs in the hypothetical set up, the non-coplanar SRI was superiority than conventional one's. The six targets were chosen in the right lung, the volume was the largest in geometric center and was decreased in hilus, bottom, anterior chest wall, lateral wall and apex of the lung in such an order. The DVH had significant change with an increasing field size. Conclusion: the irradiation damage of normal pulmonary tissue was the lowest using the six non-coplanar 120° arcs with a 30° separation between arcs by <5×5 cm2 field and the position of target was not a restricting factor.

  4. Pinitol targets nuclear factor-kappaB activation pathway leading to inhibition of gene products associated with proliferation, apoptosis, invasion, and angiogenesis.

    Science.gov (United States)

    Sethi, Gautam; Ahn, Kwang Seok; Sung, Bokyung; Aggarwal, Bharat B

    2008-06-01

    Pinitol (3-O-methyl-chiroinositol), a component of traditional Ayurvedic medicine (talisapatra), has been shown to exhibit anti-inflammatory and antidiabetic activities through undefined mechanisms. Because the transcription factor nuclear factor-kappaB (NF-kappaB) has been linked with inflammatory diseases, including insulin resistance, we hypothesized that pinitol must mediate its effects through modulation of NF-kappaB activation pathway. We found that pinitol suppressed NF-kappaB activation induced by inflammatory stimuli and carcinogens. This suppression was not specific to cell type. Besides inducible, pinitol also abrogated constitutive NF-kappaB activation noted in most tumor cells. The suppression of NF-kappaB activation by pinitol occurred through inhibition of the activation of IkappaBalpha kinase, leading to sequential suppression of IkappaBalpha phosphorylation, IkappaBalpha degradation, p65 phosphorylation, p65 nuclear translocation, and NF-kappaB-dependent reporter gene expression. Pinitol also suppressed the NF-kappaB reporter activity induced by tumor necrosis factor receptor (TNFR)-1, TNFR-associated death domain, TNFR-associated factor-2, transforming growth factor-beta-activated kinase-1 (TAK-1)/TAK1-binding protein-1, and IkappaBalpha kinase but not that induced by p65. The inhibition of NF-kappaB activation thereby led to down-regulation of gene products involved in inflammation (cyclooxygenase-2), proliferation (cyclin D1 and c-myc), invasion (matrix metalloproteinase-9), angiogenesis (vascular endothelial growth factor), and cell survival (cIAP1, cIAP2, X-linked inhibitor apoptosis protein, Bcl-2, and Bcl-xL). Suppression of these gene products by pinitol enhanced the apoptosis induced by TNF and chemotherapeutic agents and suppressed TNF-induced cellular invasion. Our results show that pinitol inhibits the NF-kappaB activation pathway, which may explain its ability to suppress inflammatory cellular responses.

  5. Relational Leading

    DEFF Research Database (Denmark)

    2015-01-01

    This first chapter presents the exploratory and curious approach to leading as relational processes – an approach that pervades the entire book. We explore leading from a perspective that emphasises the unpredictable challenges and triviality of everyday life, which we consider an interesting......, relevant and realistic way to examine leading. The chapter brings up a number of concepts and contexts as formulated by researchers within the field, and in this way seeks to construct a first understanding of relational leading....

  6. Mechanism of untargeted mutagenesis in UV-irradiated yeast

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, C.W.; Christensen, R.B.

    1982-06-01

    The SOS error-prone repair hypothesis proposes that untargeted and targeted mutations in E. coli both result from the inhibition of polymerase functions that normally maintain fidelity, and that this is a necessary precondition for translesion synthesis. Using mating experiments with excision deficient strains of Bakers' yeast, Saccharomyces cerevisiae, we find that up to 40% of cycl-91 revertants induced by UV are untargeted, showing that a reduction in fidelity is also found in irradiated cells of this organism. We are, however, unable to detect the induction or activation of any diffusible factor capable of inhibiting fidelity, and therefore suggest that untargeted and targeted mutations are the consequence of largely different processes. We propose that these observations are best explained in terms of a limited fidelity model. Untargeted mutations are thought to result from the limited capacity of processes which normally maintain fidelity, which are active during replication on both irradiated and unirradiated templates. Even moderate UV fluences saturate this capacity, leading to competition for the limited resource. Targeted mutations are believed to result from the limited, though far from negligible, capacity of lesions like pyrimidine dimers to form Watson-Crick base pairs.

  7. Dosimetry Formalism and Implementation of a Homogenous Irradiation Protocol to Improve the Accuracy of Small Animal Whole-Body Irradiation Using a 137Cs Irradiator.

    Science.gov (United States)

    Brodin, N Patrik; Chen, Yong; Yaparpalvi, Ravindra; Guha, Chandan; Tomé, Wolfgang A

    2016-02-01

    Shielded Cs irradiators are routinely used in pre-clinical radiation research to perform in vitro or in vivo investigations. Without appropriate dosimetry and irradiation protocols in place, there can be large uncertainty in the delivered dose of radiation between irradiated subjects that could lead to inaccurate and possibly misleading results. Here, a dosimetric evaluation of the JL Shepard Mark I-68A Cs irradiator and an irradiation technique for whole-body irradiation of small animals that allows one to limit the between subject variation in delivered dose to ±3% are provided. Mathematical simulation techniques and Gafchromic EBT film were used to describe the region within the irradiation cavity with homogeneous dose distribution (100% ± 5%), the dosimetric impact of varying source-to-subject distance, and the variation in attenuation thickness due to turntable rotation. Furthermore, an irradiation protocol and dosimetry formalism that allows calculation of irradiation time for whole-body irradiation of small animals is proposed that is designed to ensure a more consistent dose delivery between irradiated subjects. To compare this protocol with the conventional irradiation protocol suggested by the vendor, high-resolution film dosimetry measurements evaluating the dose difference between irradiation subjects and the dose distribution throughout subjects was performed using phantoms resembling small animals. Based on these results, there can be considerable variation in the delivered dose of > ± 5% using the conventional irradiation protocol for whole-body irradiation doses below 5 Gy. Using the proposed irradiation protocol this variability can be reduced to within ±3% and the dosimetry formalism allows for more accurate calculation of the irradiation time in relation to the intended prescription dose.

  8. The ISOLDE target robots

    CERN Multimedia

    Maximilein Brice

    2002-01-01

    ISOLDE targets need to be changed frequently, around 80 times per year. The high radiation levels do not permit this to be done by human hands and the target changes are effected by 2 industrial robots (picture _01). On the left, in the distance, the front-end of the GPS (General Purpose Separator) is seen, while the HRS (High Resolution Separator) is at the right. Also seen are the doors to the irradiated-target storage.

  9. Irradiation history of meteoritic inclusions

    DEFF Research Database (Denmark)

    Wielandt, Daniel Kim Peel

    somewhat philosophical question. . . did our solar system form under special circumstances, and what are the implications for the occurrence of similar planetary systems and ultimately life around other stars? In this thesis, we present methods and measurements pertaining to the study of irradiation......K anomalies were formed during co-storage in the protoplanetary disc, providing constraints on the disc dynamics leading up to planet formation....

  10. Effect of neon plasma pre-irradiation on surface morphology and deuterium retention of tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, L., E-mail: L.Cheng@buaa.edu.cn [School of Physics & Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); De Temmerman, G.; Zeijlmans van Emmichoven, P.A. [FOM Institute DIFFER, Dutch Institute For Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregion Cluster, Nieuwegein (Netherlands); Ji, G. [Unité Matériaux et Transformations, UMR CNRS 8207, Université Lille 1, 59655 Villeneuve d’Ascq (France); Zhou, H.B. [School of Physics & Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Wang, B. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China); Yuan, Y., E-mail: yueyuan@buaa.edu.cn [School of Physics & Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhang, Y. [School of Physics & Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Lu, G.H., E-mail: LGH@buaa.edu.cn [School of Physics & Nuclear Energy Engineering, Beihang University, Beijing 100191 (China)

    2015-08-15

    Neon and deuterium plasma irradiation of polycrystalline tungsten targets have been performed at high fluxes of ∼10{sup 24} ions m{sup −2} s{sup −1} to study the interaction of neon with tungsten and the influence of neon on deuterium retention. Tungsten exposure to neon plasma leads to the formation of wavy nanostructures on the surface. Subsequent exposure to high-flux deuterium plasma leads to blister formation of micrometer size on top of the wavy structures. The total deuterium retention is decreased by neon pre-irradiation for all surface temperatures used in the present experiments. It is suggested that a barrier of trapped Ne is formed that interrupts the D transport and reduces D retention.

  11. Target materials for exotic ISOL beams

    CERN Document Server

    Gottberg, A

    2016-01-01

    The demand for intensity, purity, reliability and availability of short-lived isotopes far from stability is steadily high, and considerably exceeding the supply. In many cases the ISOL (Isotope Separation On-Line) method can provide beams of high intensity and purity. Limitations in terms of accessible chemical species and minimum half-life are driven mainly by chemical reactions and physical processes inside of the thick target. A wide range of materials are in use, ranging from thin metallic foils and liquids to refractory ceramics, while poly-phasic mixed uranium carbides have become the reference target material for most ISOL facilities world-wide. Target material research and development is often complex and especially important post-irradiation analyses are hindered by the high intrinsic radiotoxicity of these materials. However, recent achievements have proven that these investigations are possible if the effort of different facilities is combined, leading to the development of new material matrices t...

  12. Food irradiation makes progress

    Energy Technology Data Exchange (ETDEWEB)

    Kooij, J. van (Joint FAO/IAEA Div. of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, Vienna (Austria))

    1984-06-01

    In the past fifteen years, food irradiation processing policies and programmes have been developed both by a number of individual countries, and through projects supported by FAO, IAEA and WHO. These aim at achieving general acceptance and practical implementation of food irradiation through rigorous investigations of its wholesomeness, technological and economic feasibility, and efforts to achieve the unimpeded movement of irradiated foods in international trade. Food irradiation processing has many uses.

  13. Irradiation Damage in Ti-{sub 3}(Si, Al)C-{sub 2}: a TEM Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Le Flem, M.; Liu, X.; Doriot, S.; Cozzika, Th. [CEA Saclay, DEN, DMN, SRMA, F-91191 Gif Sur Yvette (France); Monnet, I. [Ctr Rech Ions Mat and Photon, CEA, IRAMIS, CIMAP, F-14076 Caen 5 (France)

    2010-07-01

    Ti{sub 3}SiC{sub 2}, belonging to MAX phases, is a potential candidate material, which could be incorporated in core components of future gas-cooled fast nuclear reactors (GFR). Despite extensive work on mechanical behavior, corrosion resistance, or electrical properties, data concerning the evolution of Ti{sub 3}SiC{sub 2} under irradiation are very limited. In this work, Ti{sub 3}(Si, Al)C{sub 2} was irradiated at room temperature with 92 MeV Xe ions to induce irradiation damage. The samples were investigated by transmission electron microscopy (TEM) through front view and cross-section observations, which allowed to follow microstructure changes from 0. 02 dpa up to 6. 67 dpa. Progressive atomic disorder versus dose was highlighted, leading to extinction of some diffraction spots (at 0. 15 dpa) and then diffuse patterns (at 3 dpa). The ABABACAC periodicity related to 3-1-2 MAX phases was lost but the image fringes of basal plans could still be identified and no amorphous ring occurred. This means that Ti{sub 3}(Si, Al)C{sub 2} was strongly affected by irradiation but did not turn to amorphous even at 6. 67 dpa. This important result was correlated to previous conclusions from X-ray diffraction and nano-indentation analysis and suggests the good behavior of Ti{sub 3}(Si, Al)C{sub 2} under irradiation in the target temperature range assigned to GFR. (authors)

  14. Mechanical properties of UV irradiated rat tail tendon (RTT) collagen.

    Science.gov (United States)

    Sionkowska, Alina; Wess, Tim

    2004-04-01

    The mechanical properties of RTT collagen tendon before and after UV irradiation have been investigated by mechanical testing (Instron). Air-dried tendon were submitted to treatment with UV irradiation (wavelength 254 nm) for different time intervals. The changes in such mechanical properties as breaking strength and percentage elongation have been investigated. The results have shown, that the mechanical properties of the tendon were greatly affected by time of UV irradiation. Ultimate tensile strength and ultimate percentage elongation decreased after UV irradiation of the tendon. Increasing UV irradiation leads to a decrease in Young's modulus of the tendon.

  15. Food irradiation in China

    Energy Technology Data Exchange (ETDEWEB)

    Wedekind, L.

    1986-08-01

    The paper concerns food irradiation in The People's Republic of China. Its use is envisaged to prolong storage times and to improve the quality of specific foodstuffs. Commercialisation in China, demonstration plants, seasonal shortages and losses, Shanghai irradiation centre, health and safety approval, prospects for wider applications and worldwide use of food irradiation, are all discussed.

  16. Lead Test

    Science.gov (United States)

    ... months, and at 3, 4, 5, and 6 years of age. A blood lead level test should be done only if the risk ... recommended if the person is symptomatic at any level below 70 mcg/dL. Because lead will pass through the blood to an unborn child, pregnant ...

  17. Irradiation effects of the zirconium oxidation and the uranium diffusion in zirconia; Effets d'irradiation sur l'oxydation du zirconium et la diffusion de l'uranium dans la zircone

    Energy Technology Data Exchange (ETDEWEB)

    Bererd, N

    2003-07-01

    The context of this study is the direct storage of spent fuel assemblies after operation in reactor. In order to obtain data on the capacities of the can as the uranium diffusion barrier, a fundamental study has been carried out for modelling the internal cladding surface under and without irradiation. The behaviour of zirconium in reactor conditions has at first been studied. A thin uranium target enriched with fissile isotope has been put on a zirconium sample, the set being irradiated by a thermal neutrons flux leading to the fission of the deposited uranium. The energetic history of the formed fission products has revealed two steps: 1)the zirconium oxidation and 2)the diffusion of uranium in the zirconia formed at 480 degrees C. A diffusion coefficient under irradiation has been measured. Its value is 10{sup -15} cm{sup 2}.s{sup -1}. In order to be able to reveal clearly the effect of the irradiation by the fission products on the zirconium oxidation, measurements of thermal oxidation and under {sup 129}Xe irradiation have been carried out. They have shown that the oxidation is strongly accelerated by the irradiation and that the temperature is negligible until 480 degrees C. On the other hand, the thermal diffusion of the uranium in zirconium and in zirconia has been studied by coupling ion implantation and Rutherford backscattering spectroscopy. This study shows that the uranium diffuses in zirconium and is trapped in zirconia in a UO{sub 3} shape. (O.M.)

  18. Lead Poisoning

    Science.gov (United States)

    ... Topics Environment & Health Healthy Living Pollution Reduce, Reuse, Recycle Science – How It Works The Natural World Games ... OTHERS: Lead has recently been found in some plastic mini-blinds and vertical blinds which were made ...

  19. Heavy-Ion Physics at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC): Feasibility Studies for Quarkonium and Drell-Yan Production

    Science.gov (United States)

    Trzeciak, B.; Da Silva, C.; Ferreiro, E. G.; Hadjidakis, C.; Kikola, D.; Lansberg, J. P.; Massacrier, L.; Seixas, J.; Uras, A.; Yang, Z.

    2017-09-01

    We outline the case for heavy-ion-physics studies using the multi-TeV lead LHC beams in the fixed-target mode. After a brief contextual reminder, we detail the possible contributions of AFTER@LHC to heavy-ion physics with a specific emphasis on quarkonia. We then present performance simulations for a selection of observables. These show that Υ (nS), J/ψ and ψ (2S) production in heavy-ion collisions can be studied in new energy and rapidity domains with the LHCb and ALICE detectors. We also discuss the relevance to analyse the Drell-Yan pair production in asymmetric nucleus-nucleus collisions to study the factorisation of the nuclear modification of partonic densities and of further quarkonium states to restore their status of golden probes of the quark-gluon plasma formation.

  20. Mutation of Glycosylation Sites in BST-2 Leads to Its Accumulation at Intracellular CD63-Positive Vesicles without Affecting Its Antiviral Activity against Multivesicular Body-Targeted HIV-1 and Hepatitis B Virus

    Directory of Open Access Journals (Sweden)

    Zhu Han

    2016-02-01

    Full Text Available BST-2/tetherin blocks the release of various enveloped viruses including HIV-1 with a “physical tethering” model. The detailed contribution of N-linked glycosylation to this model is controversial. Here, we confirmed that mutation of glycosylation sites exerted an effect of post-translational mis-trafficking, leading to an accumulation of BST-2 at intracellular CD63-positive vesicles. BST-2 with this phenotype potently inhibited the release of multivesicular body-targeted HIV-1 and hepatitis B virus, without affecting the co-localization of BST-2 with EEA1 and LAMP1. These results suggest that N-linked glycosylation of human BST-2 is dispensable for intracellular virion retention and imply that this recently discovered intracellular tethering function may be evolutionarily distinguished from the canonical antiviral function of BST-2 by tethering nascent virions at the cell surface.

  1. Ultrasonic Transducer Irradiation Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmer, Joe [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Keller, Paul [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chien, Hual-Te [Argonne National Lab. (ANL), Argonne, IL (United States); Kohse, Gordon [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Tittmann, Bernhard [Pennsylvania State Univ., University Park, PA (United States); Reinhardt, Brian [Pennsylvania State Univ., University Park, PA (United States); Rempe, Joy [Rempe and Associates, Idaho Falls, ID (United States)

    2015-02-01

    Ultrasonic technologies offer the potential for high-accuracy and -resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other ongoing efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. For this reason, the Pennsylvania State University (PSU) was awarded an ATR NSUF project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The goal of this research is to characterize and demonstrate magnetostrictive and piezoelectric transducer operation during irradiation, enabling the development of novel radiation-tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, one piezoelectric

  2. Grape seed extract targets mitochondrial electron transport chain complex III and induces oxidative and metabolic stress leading to cytoprotective autophagy and apoptotic death in human head and neck cancer cells.

    Science.gov (United States)

    Shrotriya, Sangeeta; Deep, Gagan; Lopert, Pamela; Patel, Manisha; Agarwal, Rajesh; Agarwal, Chapla

    2015-12-01

    Head and neck squamous cell carcinoma (HNSCC) is a major killer worldwide and innovative measures are urgently warranted to lower the morbidity and mortality caused by this malignancy. Aberrant redox and metabolic status in HNSCC cells offer a unique opportunity to specifically target cancer cells. Therefore, we investigated the efficacy of grape seed extract (GSE) to target the redox and bioenergetic alterations in HNSCC cells. GSE treatment decreased the mitochondrial electron transport chain complex III activity, increased the mitochondrial superoxide levels and depleted the levels of cellular antioxidant (glutathione), thus resulting in the loss of mitochondrial membrane potential in human HNSCC Detroit 562 and FaDu cells. Polyethylene glycol-SOD addition reversed the GSE-mediated apoptosis without restoring complex III activity. Along with redox changes, GSE inhibited the extracellular acidification rate (representing glycolysis) and oxygen consumption rate (indicating oxidative phosphorylation) leading to metabolic stress in HNSCC cells. Molecular studies revealed that GSE activated AMP-activated protein kinase (AMPK), and suppressed Akt/mTOR/4E-BP1/S6K signaling in both Detroit 562 and FaDu cells. Interestingly, GSE increased the autophagic load specifically in FaDu cells, and autophagy inhibition significantly augmented the apoptosis in these cells. Consistent with in vitro results, in vivo analyses also showed that GSE feeding in nude mice activated AMPK and induced-autophagy in FaDu xenograft tumor tissues. Overall, these findings are innovative as we for the first time showed that GSE targets ETC complex III and induces oxidative and metabolic stress, thereby, causing autophagy and apoptotic death in HNSCC cells. © 2014 Wiley Periodicals, Inc.

  3. Signalling pathways induced in cells exposed to medium from irradiated cells

    Energy Technology Data Exchange (ETDEWEB)

    Lyng, F.M.; Maguire, P. (Radiation and Environmental Science Centre, Focas Institute, Dublin Institute of Technology, Dublin (Ireland)); McClean, B.; Seymour, C.; Mothersill, C. (St Luke' s Hospital, Dublin (Ireland))

    2008-12-15

    In recent years, radiation induced bystander effects have been reported in cells which were not themselves irradiated but were either in the vicinity of irradiated cells or exposed to medium from irradiated cells. The effects have been clearly shown to occur both in vivo and in vitro. This work has led to a paradigm shift in radiobiology over the last 5 - 10 years. The target theory of radiation induced effects is now being challenged because of an increasing number of studies which demonstrate non(DNA)-targeted effects. These effects appear to be particularly important at low doses. Considerable evidence now exists relating to radiation-induced bystander effects but the mechanisms involved in the transduction of the signal are still unclear. Cell - cell communication through gap junctions and / or secretion of a cytotoxic factor into the medium are thought to be involved in the transduction of the bystander signal. Oxidative metabolism has been shown to be important in both mechanisms. Signalling pathways leading to apoptosis, such as calcium, MAP kinase, mitochondrial and reactive oxygen species (ROS) signalling are discussed. The importance of oxidative metabolism and calcium signalling in bystander responses are demonstrated. Further investigations of these signalling pathways may aid in the identification of novel therapeutic targets. (orig.)

  4. Dose measurement for systemic irradiation with a moving table specially designed for total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Oda, Makoto; Oida, Masatada; Nagumo, Junya; Fujita, Katsuhisa; Furuya, Teruo; Watanabe, Yoshiharu [Hokkaido Univ., Sapporo (Japan). Hospital

    2001-07-01

    Total body irradiation (TBI) is performed in combination with chemotherapy to kill malignant tumor cells in the body prior to bone marrow transplantation. This study reports the results of dose measurements required for clinical application of the moving table technique to TBI. Since irradiation is performed as the table moves, the authors gathered sufficient basic data for irradiation by measuring output dose, tissue peak dose ratio (TPR), and the relationship between dose rate and movement velocity. The output doses were varied according to dose rate, movement velocity, radiation field, and source-target distance (STD) under these conditions. The authors measured the relationship between the dose rate and the movement velocity with the irradiation field and STD set to fit clinical applications. TPR during irradiation while moving differs from TPR during stationary irradiation, and it was measured according to the method of irradiation. The effect of body thickness was easily corrected by changing the movement velocity during the measurements. The authors measured the dose with a thermoluminescent dosimeter (TLD) during clinical application and confirmed the accuracy of the measurements. TBI with the moving table, it makes possible to perform bilateral irradiation in both posterior-anterior and anterior-posterior directions with the patient in the supine position, to reduce treatment time, to shield the lung well with reproducibility of posture, and to treat with high accuracy. (K.H.)

  5. Ion-stimulated Gas Desorption Yields of Electropolished, Chemically Etched, and Coated (Au, Ag, Pd, TiZrV) Stainless Steel Vacuum Chambers and St707 Getter Strips Irradiated with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Malabaila, M; Taborelli, M

    2005-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy Ion Accelerator LINAC 3, has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting under grazing incidence on different accelerator-type vacuum chambers. Desorption yields for H2, CH4, CO, and CO2, which are of fundamental interest for future accelerator applications, are reported for different stainless steel surface treatments. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, palladium-, and getter-coated 316 LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analysed for chemical composition by X-ray Photoemission Spectroscopy (XPS). The large effective desorption yield of 2 x 104 molecules/Pb53+ ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble-metal coating by up to 2 orders of magnitude. In addition, pressure rise measurements, the effectiveness of beam scrubbing with le...

  6. Leading men

    DEFF Research Database (Denmark)

    Bekker-Nielsen, Tønnes

    2016-01-01

    Through a systematic comparison of c. 50 careers leading to the koinarchate or high priesthood of Asia, Bithynia, Galatia, Lycia, Macedonia and coastal Pontus, as described in funeral or honorary inscriptions of individual koinarchs, it is possible to identify common denominators but also...

  7. Lead grids

    CERN Multimedia

    1974-01-01

    One of the 150 lead grids used in the multiwire proportional chamber g-ray detector. The 0.75 mm diameter holes are spaced 1 mm centre to centre. The grids were made by chemical cutting techniques in the Godet Workshop of the SB Physics.

  8. Neutronic and thermal-hydraulic analysis of a device for irradiation of LEU UAl{sub x}-Al targets for {sup 99}Mo production in the IEA-R1 reactor; Analises neutronica e termo-hidraulica de um dispositivo para irradiacao de alvos tipo LEU de UAl{sub x}-Al para producao de {sup 99}MO no reator IEA-R1

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, Pedro Julio Batista de Oliveira

    2012-07-01

    Technetium-99m ({sup 99m}Tc), the product of radioactive decay of molybdenum-99 ( Mo), is one of the most widely used radioisotope in nuclear medicine, covering approximately 80% of all radiodiagnosis procedures in the world. Nowadays, Brazil requires an amount of about 450 Ci of {sup 99}Mo per week. Due to the crisis and the shortage of {sup 99}Mo supply chain that has been observed on the world since 2008, IPEN/CNEN-SP decided to develop a project to produce {sup 99}Mo through fission of uranium-235. The objective of this dissertation was the development of neutronic and thermal-hydraulic calculations to evaluate the operational safety of a device for {sup 99}Mo production to be irradiated in the IEA-Rl reactor core at 5 MW. In this device will be placed ten targets of UAl{sub x}-Al dispersion fuel with low enriched uranium (LEU) and density of 2.889 gU/cm{sup 3}. For the neutronic calculations were utilized the computer codes HAMMER-TECHNION and CITATION and the maximum temperatures reached in the targets were calculated with the code MTRCR-IEA-R1. The analysis demonstrated that the device irradiation will occur without adverse consequences to the operation of the reactor. The total amount of {sup 99}Mo was calculated with the program SCALE and considering that the time needed for the chemical processing and recovering of the {sup 99}Mo will be five days after the irradiation, we have that the {sup 99}Mo activity available for distribution will be 176 Ci for 3 days of irradiation, 236 Ci for 5 days of irradiation and 272 Ci for 7 days of targets irradiation. (author)'.

  9. Theory of laser ion acceleration from a foil target of nanometer thickness

    Science.gov (United States)

    Yan, X. Q.; Tajima, T.; Hegelich, M.; Yin, L.; Habs, D.

    2010-03-01

    A theory for ion acceleration by ultrashort laser pulses is presented to evaluate the maximum ion energy in the interaction of ultrahigh contrast (UHC) intense laser pulses with a nanometer-scale foil. In this regime, the ion energy may be directly related to the laser intensity and subsequent electron dynamics. This leads to a simple analytical expression for the ion energy gain under the laser irradiation of thin targets. Significantly higher energies for thin targets than for thicker targets are predicted. The theory is concretized with a view to compare with the results and their details of recent experiments.

  10. Production study of high specific activity NCA Re-186g by proton and deuteron cyclotron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bonardi, M.L., E-mail: mauro.bonardi@mi.infn.i [L.A.S.A., Radiochemistry Laboratory, Universita degli Studi di Milano, UNIMI and Istituto Nazionale di Fisica Nucleare, INFN, Via F.lli Cervi 201, I-20090 Segrate (Italy); Groppi, F.; Manenti, S.; Persico, E.; Gini, L. [L.A.S.A., Radiochemistry Laboratory, Universita degli Studi di Milano, UNIMI and Istituto Nazionale di Fisica Nucleare, INFN, Via F.lli Cervi 201, I-20090 Segrate (Italy)

    2010-09-15

    Very high specific activity (A{sub S}) {sup 186g}Re could be produced by either proton or deuteron cyclotron irradiation on highly enriched {sup 186}W target in no-carrier-added (NCA) form, leading to a A{sub S} very close to the theoretical carrier free (CF) value of 6.88 GBq {mu}g{sup -1}. Thick target yields (TTYs), obtained irradiating both thick metal W targets of natural isotopic composition and highly enriched pressed powdered {sup 186}W targets, were measured at different particles energies taking into account high accuracy and precision on both yield and beam energy. The measurement of radionuclidic purity of {sup 186g}Re obtained activating highly enriched {sup 186}W by both p and d beams were also carried out and accurately compared. The excitation function as thin-target yields (tty, i.e. proportional to the reaction cross-sections) and the integrated TTYs for all Re (A=181, 182, 183, 184, 186 and their metastable levels), W and Ta co-produced radionuclides will be presented elsewhere in deep details.

  11. Mechanical properties for irradiated face-centred cubic nanocrystalline metals

    Science.gov (United States)

    Xiao, X. Z.; Song, D. K.; Chu, H. J.; Xue, J. M.; Duan, H. L.

    2015-01-01

    In this paper, a self-consistent plasticity theory is proposed to model the mechanical behaviours of irradiated face-centred cubic nanocrystalline metals. At the grain level, a tensorial crystal model with both irradiation and grain size effects is applied for the grain interior (GI), whereas both grain boundary (GB) sliding with irradiation effect and GB diffusion are considered in modelling the behaviours of GBs. The elastic-viscoplastic self-consistent method with considering grain size distribution is developed to transit the microscopic behaviour of individual grains to the macroscopic properties of nanocrystals (NCs). The proposed theory is applied to model the mechanical properties of irradiated NC copper, and the feasibility and efficiency have been validated by comparing with experimental data. Numerical results show that: (i) irradiation-induced defects can lead to irradiation hardening in the GIs, but the hardening effect decreases with the grain size due to the increasing absorption of defects by GBs. Meanwhile, the absorbed defects would make the GBs softer than the unirradiated case. (ii) There exists a critical grain size for irradiated NC metals, which separates the grain size into the irradiation hardening dominant region (above the critical size) and irradiation softening dominant region (below the critical size). (iii) The distribution of grain size has a significant influence on the mechanical behaviours of both irradiated and unirradiated NCs. The proposed model can offer a valid theoretical foundation to study the irradiation effect on NC materials. PMID:27547091

  12. Dosimetric Analyses of Single Particle Microbeam in Cell Irradiation Experiment

    Institute of Scientific and Technical Information of China (English)

    XU YongJian; JIANG Jiang; CHEN Lianyun; ZHAN Furu; YU Zengliang

    2008-01-01

    Single particle microbeam (SPM) is uniquely capable of delivering precisely the predefined number of charged particles to determined individual cells or sub-cellular targets in situ. It has been recognized as a powerful technique for unveiling ionization irradiation mechanisms of organism. This article describes some investigations on the irradiation quality of SPM of major world laboratories by means of Monte Carlo method based on dosimetry and microdosimetry. Those parameters are helpful not only to improve SPM irradiating cell experiments but also to study the biological effects of cells irradiated by SPM.

  13. Who Leads China's Leading Universities?

    Science.gov (United States)

    Huang, Futao

    2017-01-01

    This study attempts to identify the major characteristics of two different groups of institutional leaders in China's leading universities. The study begins with a review of relevant literature and theory. Then, there is a brief introduction to the selection of party secretaries, deputy secretaries, presidents and vice presidents in leading…

  14. Modelling property changes in graphite irradiated at changing irradiation temperature

    CSIR Research Space (South Africa)

    Kok, S

    2011-01-01

    Full Text Available A new method is proposed to predict the irradiation induced property changes in nuclear; graphite, including the effect of a change in irradiation temperature. The currently used method; to account for changes in irradiation temperature, the scaled...

  15. Leading Cities

    DEFF Research Database (Denmark)

    Pogner, Karl-Heinz

    2017-01-01

    and technical engineering; Smart Cities) is very prominent in the traditional mass media discourse, in PR / PA of tech companies and traditional municipal administrations; whereas the second one (participation; Livable Cities) is mostly enacted in social media, (local) initiatives, movements, (virtual......) communities, new forms of urban governance in municipal administration and co-competitive city networks. Both forms seem to struggle for getting voice and power in the discourses, negotiations, struggles, and conflicts in Urban Governance about the question how to manage or lead (in) a city. Talking about...

  16. Irradiation Creep in Graphite

    Energy Technology Data Exchange (ETDEWEB)

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13

    An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

  17. Localized irradiations, Evaluation through ''comet assay''

    Energy Technology Data Exchange (ETDEWEB)

    Giorgio, M.D.; Taja, M.R.; Nasazzi, N.B. [Autoridad Regulatoria Nuclear (Argentina); Bustos, N.; Cavalieri, H.; Bolgiani, A.

    2000-05-01

    During the last 50 years various radiation accidents involving localized irradiations occurred, resulting mainly from improper handling of sealed sources Co{sup 60}, Cs{sup 137} or Ir{sup 192} at workplaces for industrial gammagraphy. Severe skin reaction may develop at the contact sites. Such inhomogeneous irradiations lead to a differential exposure of lymphocytes in lymphatic tissues or other organs that may recirculate into the peripheral blood producing a mixed irradiated and unirradiated population of lymphocytes. Applying the mathematical models ''Contaminated Poisson'' of Dolphin and Qdr method of Sasaki, a mean dose in the irradiated body area and its size can be estimated from unstable chromosome aberration scoring. This give an indication of the proportion of haemopoietic stem cell compartment involved in the overexposure. There are also different biophysical techniques that can give responses in biological dosimetry. The ''Comet Assay'' (single cell gel electrophoresis) is a sensitive and rapid method for DNA strand break detection in individual cells. The advantages of the technique include: collection of data at the level of individual cell; the need for small numbers of cells per sample; its sensitivity for detecting DNA damage and that virtually any eukaryote cell population is amenable to analysis. The objective of this work is to apply ''Comet Assay'' method to evaluate the effect of radiation on skin and subcutaneous tissues, differentiating irradiated from unirradiated body areas. It could provide a useful tool to estimate the extension and the dose in the irradiated region, contributing with the current techniques. In this first study, we evaluate the alkaline comet assay as a method for detection of DNA radiation induced damage in keratinocytes from primary culture obtained from full thickness skin biopsies of patients requiring grafts. Skin and, particularly, keratinocytes were

  18. Gene and miRNA expression profiles of mouse Lewis lung carcinoma LLC1 cells following single or fractionated dose irradiation.

    Science.gov (United States)

    Stankevicius, Vaidotas; Kuodyte, Karolina; Schveigert, Diana; Bulotiene, Danute; Paulauskas, Tomas; Daniunaite, Kristina; Suziedelis, Kestutis

    2017-06-01

    In clinical practice ionizing radiation (IR) is primarily applied to cancer treatment in the form of fractionated dose (FD) irradiation. Despite this fact, a substantially higher amount of current knowledge in the field of radiobiology comes from in vitro studies based on the cellular response to single dose (SD) irradiation. In addition, intrinsic and acquired resistance to IR remains an issue in clinical practice, leading to radiotherapy treatment failure. Numerous previous studies suggest that an improved understanding of the molecular processes involved in the radiation-induced DNA damage response to FD irradiation could improve the effectiveness of radiotherapy. Therefore, the present study examined the differential expression of genes and microRNA (miRNA) in murine Lewis lung cancer (LLC)1 cells exposed to SD or FD irradiation. The results of the present study indicated that the gene and miRNA expression profiles of LLC1 cells exposed to irradiation were dose delivery type-dependent. Data analysis also revealed that mRNAs may be regulated by miRNAs in a radiation-dependent manner, suggesting that these mRNAs and miRNAs are the potential targets in the cellular response to SD or FD irradiation. However, LLC1 tumors after FD irradiation exhibited no significant changes in the expression of selected genes and miRNAs observed in the irradiated cells in vitro, suggesting that experimental in vitro conditions, particularly the tumor microenvironment, should be considered in detail to promote the development of efficient radiotherapy approaches. Nevertheless, the present study highlights the primary signaling pathways involved in the response of murine cancer cells to irradiation. Data presented in the present study can be applied to improve the outcome and development of radiotherapy in preclinical animal model settings.

  19. 碳酚醛-铝板中二维X射线热击波数值模拟%2-D numerical simulation of thermal shock wave induced by X-ray irradiation in carbon fiber-reinforced phenolic aluminum target

    Institute of Scientific and Technical Information of China (English)

    黄霞; 汤文辉; 蒋邦海

    2011-01-01

    Using the plane-strain anisotropic rate-related elasto-plastic constitutive model and the ideal isotropic elasto-plastic constitutive model, the thermal shock wave propagation induced by X-ray irradiation in carbon fiber-reinforced phenolic-aluminum plate is simulated by finite element method.The results show that under the irradiation of X-ray of 1 keV, the penetration depth is small, the material surface is gasified, and the peak stress values are high; but under the irradiation of X-ray of 3keV, the penetration depth is much increased, the thermal shock wave takes a double-wave shape, and the delamination phenomenon is more significant.%文章利用平面应变正交各向异性材料率相关性的弹塑性本构模型和各向同性材料理想弹塑性本构模型,采用有限元方法编写程序,对X射线辐照碳酚醛-铝板时诱导的热击波进行数值模拟,讨论了热击波的传播规律.结果表明,在1 kev的X射线辐照下,X射线穿透极浅,材料表面发生气化现象,应力峰值较大;在3keV的X射线辐照下,X射线穿透较深,热击波呈现双波结构,材料的层裂更明显.

  20. ENHANCING FOOD SAFETY AND STABILITY THROUGH IRRADIATION: A REVIEW

    Directory of Open Access Journals (Sweden)

    Manzoor Ahmad Shah

    2014-04-01

    Full Text Available Food irradiation is one of the non thermal food processing methods. It is the process of exposing food materials to the controlled amounts of ionizing radiations such as gamma rays, X-rays and accelerated electrons, to improve microbiological safety and stability. Irradiation disrupts the biological processes that lead to decay of food quality. It is an effective tool to reduce food-borne pathogens, spoilage microorganisms and parasites; to extend shelf-life and for insect disinfection. The safety and consumption of irradiated foods have been extensively studied at national levels and in international cooperations and have concluded that foods irradiated under appropriate technologies are both safe and nutritionally adequate. Specific applications of food irradiation have been approved by national legislations of more than 55 countries worldwide. This review aims to discuss the applications of irradiation in food processing with the emphasis on food safety and stability.

  1. Pollen irradiation and possible gene transfer in Nicotiana species

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1985-01-01

    Progeny from crosses of Nicotiana langsdorffii with gamma irradiated pollen of Nicotiana alata ‘Crimson Bedder’ showed skewed segregation in the F2 favoring the maternal parent. This is probably not gene transfer in a strict sense, rather just an extreme case of reduced transmission of irradiated...... chromosomes, leading to massive overrepresentation of maternal genes. Gene transfer or mutational loss may explain some anomalous F1 plants. Segregation in the F2 progeny showed the presence of several genes from the irradiated pollen. Crosses of Nicotiana sylvestris, N. plumbaginifolia N. paniculata......, and Petunia parodii with irradiated pollen from N. alata and Petunia hybrida showed no evidence of gene transfer, nor did experiments with irradiated mentor pollen. This indicates that gene transfer with irradiated pollen between non-crossing species or between species giving sterile hybrids is probably...

  2. The IRMA gamma irradiation facility

    Energy Technology Data Exchange (ETDEWEB)

    Berger, L.; Raboin, M.; Corbiere, J. [IRSN, Fontenat-aux-roses (France)

    2011-07-01

    The IRMA cobalt-60 irradiation cell has been installed at the Saclay research centre (25 km from Paris) for 40 years. IRMA is a facility with a maximum authorized capacity of 1, 700 TBq (i.e. approx. 46, 000 Ci). It is a test facility intended primarily for research and development studies on how equipment and materials respond to dose or dose rate exposure. Cobalt-60 gamma photons are the reference in this field. Irradiation is panoramic and achieved using 4, independent, cylindrical sealed sources (11 mm in diameter and 452 mm in length). When not in use, the sources are stored in a lead cask with 0.30 m thick walls to allow safe access inside the cell (uncontaminated environment). With an internal volume of 24 m{sup 3}, it can accommodate a very wide variety of geometric configurations for exposure to gamma radiation. Available dose rates range from 5 {mu}Gy/h (which is the background radiation in the cell when the sources are enclosed in their lead cask) to 25 kGy/h (value obtained 10 cm from a source holder containing all four sources). The resulting doses can be used in experiments representing relatively extreme situations (reactor accidents, dose after x years for equipment in hot cells, reprocessing plants, and so on).The IRMA facility has performed several irradiation tests on new components for EPR and LWR. The IRMA facility is also adapted to check the performance of new biological shieldings and protections for reactors and reprocessing plants. In several other fields of nuclear applications, this facility is useful to characterize and calibrate radiation detectors for the nuclear, space, and military industries

  3. How to improve the irradiation conditions for the International Fusion Materials Irradiation Facility

    CERN Document Server

    Daum, E

    2000-01-01

    The accelerator-based intense D-Li neutron source International Fusion Materials Irradiation Facility (IFMIF) provides very suitable irradiation conditions for fusion materials development with the attractive option of accelerated irradiations. Investigations show that a neutron moderator made of tungsten and placed in the IFMIF test cell can further improve the irradiation conditions. The moderator softens the IFMIF neutron spectrum by enhancing the fraction of low energy neutrons. For displacement damage, the ratio of point defects to cascades is more DEMO relevant and for tritium production in Li-based breeding ceramic materials it leads to a preferred production via the sup 6 Li(n,t) sup 4 He channel as it occurs in a DEMO breeding blanket.

  4. Neutronic performances of the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, S.; Bringer, O.; Chabod, S.; Dupont, E.; Letourneau, A. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPhN), 91- Gif sur Yvette (France); Beauvais, P.; Lotrus, P.; Molinie, F.; Toussaint, J.Ch. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA), 91- Gif sur Yvette (France); Chartier, F. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Oriol, L. [CEA Cadarache, Dept. d' Etudes des Reacteurs (DEN/DER/SPEX), 13 - Saint Paul lez Durance (France)

    2008-07-01

    The MEGAPIE project is a key experiment on the road to Accelerator Driven Systems and it provides the scientific community with unique data on the behavior of a liquid lead-bismuth spallation target under realistic and long term irradiation conditions. The neutronic of such target is of course of prime importance when considering its final destination as an intense neutron source. This is the motivation to characterize the inside neutron flux of the target in operation. A complex detector, made of 8 'micro' fission-chambers, has been built and installed in the core of the target, few tens of centimeters from the proton/Pb-Bi interaction zone. This detector is designed to measure the absolute neutron flux inside the target, to give its spatial distribution and to correlate its temporal variations with the beam intensity. Moreover, integral information on the neutron energy distribution as a function of the position along the beam axis could be extracted, giving integral constraints on the neutron production models implemented in transport codes such as MCNPX. (authors)

  5. Neutronic performances of the MEGAPIE target

    CERN Document Server

    Panebianco, S; Bringer, O; Chabod, S; Chartier, F; Dupont, E; Letourneau, A; Lotrus, P; Oriol, L; Molinie, F; Toussaint, J Ch

    2007-01-01

    The MEGAPIE project is a key experiment on the road to Accelerator Driven Systems and it provides the scientific community with unique data on the behavior of a liquid lead-bismuth spallation target under realistic and long term irradiation conditions. The neutronic of such target is of course of prime importance when considering its final destination as an intense neutron source. This is the motivation to characterize the inside neutron flux of the target in operation. A complex detector, made of 8 micro fission-chambers, has been built and installed in the core of the target, few tens of centimeters from the proton/Pb-Bi interaction zone. This detector is designed to measure the absolute neutron flux inside the target, to give its spatial distribution and to correlate its temporal variations with the beam intensity. Moreover, integral information on the neutron energy distribution as a function of the position along the beam axis could be extracted, giving integral constraints on the neutron production mode...

  6. AGC-2 Irradiation Report

    Energy Technology Data Exchange (ETDEWEB)

    Rohrbaugh, David Thomas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Windes, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Swank, W. David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-06-01

    The Next Generation Nuclear Plant (NGNP) will be a helium-cooled, very high temperature reactor (VHTR) with a large graphite core. In past applications, graphite has been used effectively as a structural and moderator material in both research and commercial high temperature gas cooled reactor (HTGR) designs.[ , ] Nuclear graphite H 451, used previously in the United States for nuclear reactor graphite components, is no longer available. New nuclear graphites have been developed and are considered suitable candidates for the new NGNP reactor design. To support the design and licensing of NGNP core components within a commercial reactor, a complete properties database must be developed for these current grades of graphite. Quantitative data on in service material performance are required for the physical, mechanical, and thermal properties of each graphite grade with a specific emphasis on data related to the life limiting effects of irradiation creep on key physical properties of the NGNP candidate graphites. Based on experience with previous graphite core components, the phenomenon of irradiation induced creep within the graphite has been shown to be critical to the total useful lifetime of graphite components. Irradiation induced creep occurs under the simultaneous application of high temperatures, neutron irradiation, and applied stresses within the graphite components. Significant internal stresses within the graphite components can result from a second phenomenon—irradiation induced dimensional change. In this case, the graphite physically changes i.e., first shrinking and then expanding with increasing neutron dose. This disparity in material volume change can induce significant internal stresses within graphite components. Irradiation induced creep relaxes these large internal stresses, thus reducing the risk of crack formation and component failure. Obviously, higher irradiation creep levels tend to relieve more internal stress, thus allowing the

  7. Irradiation Defects in Silicon Crystal

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The application of irradiation in silicon crystal is introduced.The defects caused by irradiation are reviewed and some major ways of studying defects in irradiated silicon are summarized.Furthermore the problems in the investigation of irradiated silicon are discussed as well as its properties.

  8. Efficient targeting of protein antigen to the dendritic cell receptor DEC-205 in the steady state leads to antigen presentation on major histocompatibility complex class I products and peripheral CD8+ T cell tolerance.

    Science.gov (United States)

    Bonifaz, Laura; Bonnyay, David; Mahnke, Karsten; Rivera, Miguel; Nussenzweig, Michel C; Steinman, Ralph M

    2002-12-16

    To identify endocytic receptors that allow dendritic cells (DCs) to capture and present antigens on major histocompatibility complex (MHC) class I products in vivo, we evaluated DEC-205, which is abundant on DCs in lymphoid tissues. Ovalbumin (OVA) protein, when chemically coupled to monoclonal alphaDEC-205 antibody, was presented by CD11c+ lymph node DCs, but not by CD11c- cells, to OVA-specific, CD4+ and CD8+ T cells. Receptor-mediated presentation was at least 400 times more efficient than unconjugated OVA and, for MHC class I, the DCs had to express transporter of antigenic peptides (TAP) transporters. When alphaDEC-205:OVA was injected subcutaneously, OVA protein was identified over a 4-48 h period in DCs, primarily in the lymph nodes draining the injection site. In vivo, the OVA protein was selectively presented by DCs to TCR transgenic CD8+ cells, again at least 400 times more effectively than soluble OVA and in a TAP-dependent fashion. Targeting of alphaDEC-205:OVA to DCs in the steady state initially induced 4-7 cycles of T cell division, but the T cells were then deleted and the mice became specifically unresponsive to rechallenge with OVA in complete Freund's adjuvant. In contrast, simultaneous delivery of a DC maturation stimulus via CD40, together with alphaDEC-205:OVA, induced strong immunity. The CD8+ T cells responding in the presence of agonistic alphaCD40 antibody produced large amounts of interleukin 2 and interferon gamma, acquired cytolytic function in vivo, emigrated in large numbers to the lung, and responded vigorously to OVA rechallenge. Therefore, DEC-205 provides an efficient receptor-based mechanism for DCs to process proteins for MHC class I presentation in vivo, leading to tolerance in the steady state and immunity after DC maturation.

  9. Efficient Targeting of Protein Antigen to the Dendritic Cell Receptor DEC-205 in the Steady State Leads to Antigen Presentation on Major Histocompatibility Complex Class I Products and Peripheral CD8+ T Cell Tolerance

    Science.gov (United States)

    Bonifaz, Laura; Bonnyay, David; Mahnke, Karsten; Rivera, Miguel; Nussenzweig, Michel C.; Steinman, Ralph M.

    2002-01-01

    To identify endocytic receptors that allow dendritic cells (DCs) to capture and present antigens on major histocompatibility complex (MHC) class I products in vivo, we evaluated DEC-205, which is abundant on DCs in lymphoid tissues. Ovalbumin (OVA) protein, when chemically coupled to monoclonal αDEC-205 antibody, was presented by CD11c+ lymph node DCs, but not by CD11c− cells, to OVA-specific, CD4+ and CD8+ T cells. Receptor-mediated presentation was at least 400 times more efficient than unconjugated OVA and, for MHC class I, the DCs had to express transporter of antigenic peptides (TAP) transporters. When αDEC-205:OVA was injected subcutaneously, OVA protein was identified over a 4–48 h period in DCs, primarily in the lymph nodes draining the injection site. In vivo, the OVA protein was selectively presented by DCs to TCR transgenic CD8+ cells, again at least 400 times more effectively than soluble OVA and in a TAP-dependent fashion. Targeting of αDEC-205:OVA to DCs in the steady state initially induced 4–7 cycles of T cell division, but the T cells were then deleted and the mice became specifically unresponsive to rechallenge with OVA in complete Freund's adjuvant. In contrast, simultaneous delivery of a DC maturation stimulus via CD40, together with αDEC-205:OVA, induced strong immunity. The CD8+ T cells responding in the presence of agonistic αCD40 antibody produced large amounts of interleukin 2 and interferon γ, acquired cytolytic function in vivo, emigrated in large numbers to the lung, and responded vigorously to OVA rechallenge. Therefore, DEC-205 provides an efficient receptor-based mechanism for DCs to process proteins for MHC class I presentation in vivo, leading to tolerance in the steady state and immunity after DC maturation. PMID:12486105

  10. Food irradiation; Napromieniowanie zywnosci

    Energy Technology Data Exchange (ETDEWEB)

    Migdal, W. [Instytut Chemii i Techniki Jadrowej, Doswiadczalna Stacja Radiacyjnego Utrwalania Plodow Rolnych, Warsaw (Poland)

    1995-12-31

    A worldwide standard on food irradiation was adopted in 1983 by codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and The World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Inst. of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19 MeV, 1 kW) and industrial unit Electronika (10 MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permissions for irradiation for; spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables. (author) 14 refs, 3 tabs

  11. Total lymphoid irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

    1983-05-01

    Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen.

  12. Irradiation effects in hydrated zirconium molybdate

    Science.gov (United States)

    Fourdrin, C.; Esnouf, S.; Dauvois, V.; Renault, J.-P.; Venault, L.; Tabarant, M.; Durand, D.; Chenière, A.; Lamouroux-Lucas, C.; Cochin, F.

    2012-07-01

    Hydrated zirconium molybdate is a precipitate formed during the process of spent nuclear fuel dissolution. In order to study the radiation stability of this material, we performed gamma and electron irradiation in a dose range of 10-100 kGy. XRD patterns showed that the crystalline structure is not affected by irradiation. However, the yellow original sample exhibits a blue-grey color after exposure. The resulting samples were analyzed by means of EPR and diffuse reflectance spectroscopy. Two sites for trapped electrons were evidenced leading to a d1 configuration responsible for the observed coloration. Moreover, a third defect corresponding to a hole trapped on oxygen was observed after electron irradiation at low temperature.

  13. Integration of three-dimensional magnetic resonance spectrometry to the irradiation treatment plan for glioblastomas: definition of new target volumes; Integration de la spectrometrie par resonance magnetique tridimensionnelle au plan de traitement par irradiation des glioblastomes: definition de nouveaux volumes cibles

    Energy Technology Data Exchange (ETDEWEB)

    Ken, S.; Vieillevigne, L.; Cohen-Jonathan, E.M.; Laprie, A. [Departement de radiotherapie, institut Claudius-Regaud, 31 - Toulouse (France); Ken, S.; Franceries, X.; Lotterie, J.A.; Lubrano, V.; Catalaa, I.; Celsis, P.; Berry, I.; Laprie, A. [Inserm UMR 825 Imagerie cerebrale et handicaps neurologiques, 31 - Toulouse (France); Lotterie, J.A.; Lubrano, V.; Berry, I. [Departement de biophysique, centre hospitalier universitaire de Rangueil, 31 - Toulouse (France); Catalaa, I. [Departement de radiologie, centre hospitalier universitaire de Purpan, 31 - Toulouse (France)

    2010-10-15

    Based on a clinic trial, the authors report the definition of a new reliable and reproducible method to delimit and integrate targets to the treatment plan which are specific to magnetic resonance spectrometry imagery for the radiotherapy of glioblastomas, in order to perform a treatment by intensity-modulated conformational radiotherapy (IMRT). A weighted conventional MRI has been performed before radiotherapy. The importation of anatomic-metabolic images into the dose planning system comprises two steps: normalization on the whole volume of magnetic resonance spectrometry imagery, and segmentation of target volumes specific to spectrometry anomalies. This integration of target volumes is thus facilitated. Short communication

  14. CONCEPTUAL PAPER : Utilization of GPS Satellites for Precise Irradiation Measurement and Monitoring

    Indian Academy of Sciences (India)

    S. Vijayan

    2008-03-01

    Precise measurement of irradiance over the earth under various circumstances like solar flares, coronal mass ejections, over an 11-year solar cycle, etc. leads to better understanding of Sun–earth relationship. To continuously monitor the irradiance over earth-space regions several satellites at several positions are required. For that continuous and multiple satellite monitoring we can use GPS (Global Positioning System) satellites (like GLONASS, GALILEO, future satellites) installed with irradiance measuring and monitoring instruments. GPS satellite system consists of 24 constellations of satellites. Therefore usage of all the satellites leads to 24 measurements of irradiance at the top of the atmosphere (or 12 measurements of those satellites which are pointing towards the Sun) at an instant. Therefore in one day, numerous irradiance observations can be obtained for the whole globe, which will be very helpful for several applications like Albedo calculation, Earth Radiation Budget calculation, monitoring of near earth-space atmosphere, etc. Moreover, measuring irradiance both in ground (using ground instruments) and in space at the same instant of time over a same place, leads to numerous advantages. That is, for a single position we obtain irradiance at the top of the atmosphere, irradiance at ground and the difference in irradiance from over top of the atmosphere to the ground. Measurement of irradiance over the atmosphere and in ground at a precise location gives more fine details about the solar irradiance influence over the earth, path loss and interaction of irradiance with the atmosphere.

  15. On the role of secondary pions in spallation targets

    Energy Technology Data Exchange (ETDEWEB)

    Mancusi, Davide [Paris-Saclay Univ., Gif-sur-Yvette (France). Den-Service d' Etude des Reacteurs et de Mathematiques Appliquees (SERMA); Lo Meo, Sergio [ENEA, Research Centre ' ' Ezio Clementel' ' , Bologna (Italy); INFN, Bologna (Italy); Colonna, Nicola [INFN, Bari (Italy); Boudard, Alain; David, Jean-Christophe; Leray, Sylvie [Paris-Saclay Univ., Gif-sur-Yvette (France). IRFU, CEA; Cortes-Giraldo, Miguel Antonio; Lerendegui-Marco, Jorge [Sevilla Univ. (Spain). Facultad de Fisica; Cugnon, Joseph [Liege Univ. (Belgium). AGO Dept.; Massimi, Cristian [INFN, Bologna (Italy); Bologna Univ. (Italy). Physics and Astronomy Dept.; Vlachoudis, Vasilis [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2017-05-15

    We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the nTOF lead spallation target, irradiated with 20 GeV/c protons, neutral pions are involved in the production of ∝ 90% of the high-energy photons; charged pions participate in ∝ 40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets. (orig.)

  16. On the role of secondary pions in spallation targets

    CERN Document Server

    Mancusi, Davide; Colonna, Nicola; Boudard, Alain; Cortés-Giraldo, Miguel Antonio; Cugnon, Joseph; David, Jean-Christophe; Leray, Sylvie; Lerendegui-Marco, Jorge; Massimi, Cristian; Vlachoudis, Vasilis

    2016-01-01

    We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20-GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.

  17. Irradiation and food processing.

    Science.gov (United States)

    Sigurbjörnsson, B; Loaharanu, P

    1989-01-01

    After more than four decades of research and development, food irradiation has been demonstrated to be safe, effective and versatile as a process of food preservation, decontamination or disinfection. Its various applications cover: inhibition of sprouting of root crops; insect disinfestation of stored products, fresh and dried food; shelf-life extension of fresh fruits, vegetables, meat and fish; destruction of parasites and pathogenic micro-organisms in food of animal origin; decontamination of spices and food ingredients, etc. Such applications provide consumers with the increase in variety, volume and value of food. Although regulations on food irradiation in different countries are largely unharmonized, national authorities have shown increasing recognition and acceptance of this technology based on the Codex Standard for Irradiated Foods and its associated Code of Practice. Harmonization of national legislations represents an important prerequisite to international trade in irradiated food. Consumers at large are still not aware of the safety and benefits that food irradiation has to offer. Thus, national and international organizations, food industry, trade associations and consumer unions have important roles to play in introducing this technology based on its scientific values. Public acceptance of food irradiation may be slow at the beginning, but should increase at a faster rate in the foreseeable future when consumers are well informed of the safety and benefits of this technology in comparison with existing ones. Commercial applications of food irradiation has already started in 18 countries at present. The volume of food or ingredients treated on a commercial scale varies from country to country ranging from several tons of spices to hundreds of thousands of tons of grains per annum. With the increasing interest of national authorities and the food industry in applying the process, it is anticipated that some 25 countries will use some 55 commercial

  18. Irradiation Testing of Ultrasonic Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua; Tittmann, Bernhard; Reinhardt, Brian; Kohse, Gordon E.; Ramuhalli, Pradeep; Montgomery, Robert O.; Chien, Hual-Te; Villard, Jean-Francois; Palmer, Joe; Rempe, Joy

    2014-07-30

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. For this reason, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2 (E> 0.1 MeV). The goal of this research is to characterize magnetostrictive and piezoelectric transducer survivability during irradiation, enabling the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). As such, this test will be an instrumented lead test and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers.

  19. Current issues in human lead exposure and regulation of lead.

    Science.gov (United States)

    Davis, J M; Elias, R W; Grant, L D

    1993-01-01

    Concern about lead as a significant public health problem has increased as epidemiological and experimental evidence has mounted regarding adverse health effects at successively lower levels of lead exposure. This concern has led to downward revision of criteria for acceptable blood lead concentrations to the 10 micrograms/dL mark now designated by EPA as a target level for regulatory development and enforcement/clean-up purposes. Much progress has been made in reducing lead exposures during the past 10-15 years, with marked declines evident both in air lead and blood lead concentrations in parallel to the phase-down of lead in gasoline and notable decreases in food lead exposure due to elimination of lead soldered cans by U.S. food processors. With the lessening of exposure from these sources, the importance of other components of multimedia exposure pathways has grown and stimulated increasing regulatory attention and abatement efforts to reduce health risks associated with lead exposure from drinking water, from lead-based paint, and from household dust and soil contaminated by deteriorating paint, smelter emissions, or various other sources. Increasing attention is also being accorded to reduction of occupational lead exposures (including those related to lead abatement activities), with particular concern for protection of men and women during their reproductive years.

  20. RERTR-7 Irradiation Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    D. M. Perez; M. A. Lillo; G. S. Chang; G. A. Roth; N. E. Woolstenhulme; D. M. Wachs

    2011-12-01

    The Reduced Enrichment for Research and Test Reactor (RERTR) experiment RERTR-7A, was designed to test several modified fuel designs to target fission densities representative of a peak low enriched uranium (LEU) burnup in excess of 90% U-235 at peak experiment power sufficient to generate a peak surface heat flux of approximately 300 W/cm2. The RERTR-7B experiment was designed as a high power test of 'second generation' dispersion fuels at peak experiment power sufficient to generate a surface heat flux on the order of 230 W/cm2.1 The following report summarizes the life of the RERTR-7A and RERTR-7B experiments through end of irradiation, including as-run neutronic analyses, thermal analyses and hydraulic testing results.

  1. Effects of irradiation on Planococcus minor (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Ravuiwasa, Kaliova Tavou; Lu, Kuang-Hui; Shen, Tse-Chi; Hwang, Shaw-Yhi

    2009-10-01

    Irradiation has been recognized and endorsed as a potential phytosanitary measure that could be an alternative to current quarantine treatments. Dosages of 50, 100, 150, 200, and 250 Gy were used to irradiate three different life stages (eggs, immatures, and adults) of Planococcus minor (Maskell) (Hemiptera: Pseudococcidae), focusing on females due to its parthenogenesis ability, with an aim to find the most tolerant stage and the most optimal dose to control P. minor. Cobalt 60 was the source of irradiation used. Irradiation of 150-250 Gy has a significant effect on all life stages of P. minor, decreasing its survival rate, percentage of adult reproduction, oviposition, and fertility rate. The adult was the most tolerant life stage in both mortality and fertility rate. All the different irradiated target life stage groups oviposited eggs, but none of the F2 eggs hatched at the most optimal dosage of 150-250 Gy.

  2. Minimizing material damage using low temperature irradiation

    Science.gov (United States)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-08-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  3. Proton beam modification of lead white pigments

    Energy Technology Data Exchange (ETDEWEB)

    Beck, L., E-mail: lucile.beck@cea.fr [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, 91191 Gif-sur-Yvette (France); Centre de recherche et de restauration des musées de France (C2RMF), Palais du Louvre – Porte des Lions, 14 quai François Mitterrand, 75001 Paris (France); Gutiérrez, P.C. [Centre de recherche et de restauration des musées de France (C2RMF), Palais du Louvre – Porte des Lions, 14 quai François Mitterrand, 75001 Paris (France); Centro de Micro-Análisis de Materiales (CMAM), Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Miserque, F. [CEA, DEN, DPC/SCCME/LECA, 91191 Gif-sur-Yvette (France); Thomé, L. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), CNRS/IN2P3 et Université Paris-Sud, Bât. 108, 91405 Orsay (France)

    2013-07-15

    Pigments and paint materials are known to be sensitive to particle irradiation. Occasionally, the analysis of paintings by PIXE can induce a slight or dark stain depending on the experimental conditions (beam current, dose, particle energy). In order to understand this discoloration, we have irradiated various types of art white pigments – lead white (hydrocerussite and basic lead sulfate), gypsum, calcite, zinc oxide and titanium oxide – with an external 3 MeV proton micro-beam commonly used for PIXE experiments. We have observed various sensitivities depending on the pigment. No visible change occurs for calcite and titanium oxide, whereas lead white pigments are very sensitive. For the majority of the studied compounds, the discoloration is proportional to the beam current and charge. The damage induced by proton beam irradiation in lead white pigments was studied by micro-Raman and XPS spectroscopies. Structural modifications and dehydration were detected. Damage recovery was investigated by thermal treatment and UV-light irradiation. The discoloration disappeared after one week of UV illumination, showing that PIXE experiments could be safely undertaken for pigments and paintings.

  4. Down-Regulation of miR-129-5p and the let-7 Family in Neuroendocrine Tumors and Metastases Leads to Up-Regulation of Their Targets Egr1, G3bp1, Hmga2 and Bach1

    DEFF Research Database (Denmark)

    Dossing, Kristina B. V.; Binderup, Tina; Kaczkowski, Bogumil

    2014-01-01

    by miR-129-5p. let-7 overexpression inhibited growth of carcinoid cell lines, and let-7 inhibition increased protein content of the transcription factor BACH1 and its targets MMP1 and HMGA2, all known to promote bone metastases. Immunohistochemistry analysis revealed that let-7 targets are highly...

  5. The Birmingham Irradiation Facility

    Science.gov (United States)

    Dervan, P.; French, R.; Hodgson, P.; Marin-Reyes, H.; Wilson, J.

    2013-12-01

    At the end of 2012 the proton irradiation facility at the CERN PS [1] will shut down for two years. With this in mind, we have been developing a new ATLAS scanning facility at the University of Birmingham Medical Physics cyclotron. With proton beams of energy approximately 30 MeV, fluences corresponding to those of the upgraded Large Hadron Collider (HL-LHC) can be reached conveniently. The facility can be used to irradiate silicon sensors, optical components and mechanical structures (e.g. carbon fibre sandwiches) for the LHC upgrade programme. Irradiations of silicon sensors can be carried out in a temperature controlled cold box that can be scanned through the beam. The facility is described in detail along with the first tests carried out with mini (1×1 cm2) silicon sensors.

  6. The Birmingham Irradiation Facility

    CERN Document Server

    Dervan, P; Hodgson, P; Marin-Reyes, H; Wilson, J

    2013-01-01

    At the end of 2012 the proton irradiation facility at the CERN PS [1] will shut down for two years. With this in mind, we have been developing a new ATLAS scanning facility at the University of Birmingham Medical Physics cyclotron. With proton beams of energy approximately 30 MeV, fluences corresponding to those of the upgraded Large Hadron Collider (HL-LHC) can be reached conveniently. The facility can be used to irradiate silicon sensors, optical components and mechanical structures (e.g. carbon fibre sandwiches) for the LHC upgrade programme. Irradiations of silicon sensors can be carried out in a temperature controlled cold box that can be scanned through the beam. The facility is described in detail along with the first tests carried out with mini (1 x 1 cm^2 ) silicon sensors.

  7. Irradiation of food

    Energy Technology Data Exchange (ETDEWEB)

    MacGregor, J.; Stanbrook, I.; Shersby, M.

    1989-07-12

    The House of Commons was asked to support the Government's intention to allow the use of the irradiation of foodstuffs under conditions that will fully safeguard the interests of the consumer. The Government, it was stated, regards this process as a useful additional way to ensure food safety. The effect of the radiation in killing bacteria will enhance safety standards in poultry meat, in some shell-fish and in herbs and spices. The problem of informing the public when the food has been irradiated, especially as there is no test to detect the irradiation, was raised. The subject was debated for an hour and a half and is reported verbatim. The main point raised was over whether the method gave safer food as not all bacteria were killed in the process. The motion was carried. (U.K.).

  8. Propagation of Plasma Generated by Intense Pulsed Ion Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    WU Di; GONG Ye; LIU Jin-Yuan; WANG Xiao-Gang; LIU Yue; MA Teng-Cai

    2006-01-01

    @@ Taking the calculation results based on the established two-dimensional ablation model of the intense-pulsed-ion-beam (IPIB) irradiation process as initial conditions, we build a two-dimensional hydrodynamic ejection model of plasma produced by an IPIB-irradiated metal titanium target into ambient gas. We obtain the conclusions that shock waves generate when the background pressure is around 133 mTorr and also obtain the plume splitting phenomenon that has been observed in the experiments.

  9. Dearomatization of jet fuel on irradiated platinum-supported catalyst

    Science.gov (United States)

    Múčka, V.; Ostrihoňová, A.; Kopernický, I.; Mikula, O.

    The effect of ionizing radiation ( 60Co γ-rays) on Pt-supported catalyst used for the dearomatization of jet fuel with distillation in the range 395-534 K has been studied. Pre-irradiation of the catalyst with doses in the range 10 2-5 × 10 4 Gy leads to the partial catalyst activation. Irradiation of the catalyst enhances its resistance to catalyst poisons, particularly to sulphur-compounds, and this is probably the reason for its catalytic activity being ˜60-100% greater than that of un-irradiated catalyst. Optimum conditions for dearomatization on the irradiated catalyst were found and, by means of a rotary three-factorial experiment, it was shown that these lie at lower temperatures and lower pressures than those for un-irradiated catalyst.

  10. Biological effect of penetration controlled irradiation with ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi; Shimizu, Takashi; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Watanabe, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Yamashita, Takao

    1997-03-01

    To investigate the effect of local irradiation with ion beams on biological systems, technique for penetration controlled irradiation has been established. The range in a target was controlled by changing the distance from beam window in the atmosphere, and could be controlled linearly up to about 31 {mu}m in biological material. In addition, the effects of the penetration controlled irradiations with 1.5 MeV/u C and He ions were examined using tobacco pollen. The increased frequency of leaky pollen produced by ion beams suggests that the efficient pollen envelope damages would be induced at the range-end of ion beams. (author)

  11. Lithium increases proliferation of hippocampal neural stem/progenitor cells and rescues irradiation-induced cell cycle arrest in vitro.

    Science.gov (United States)

    Zanni, Giulia; Di Martino, Elena; Omelyanenko, Anna; Andäng, Michael; Delle, Ulla; Elmroth, Kecke; Blomgren, Klas

    2015-11-10

    Radiotherapy in children causes debilitating cognitive decline, partly linked to impaired neurogenesis. Irradiation targets primarily cancer cells but also endogenous neural stem/progenitor cells (NSPCs) leading to cell death or cell cycle arrest. Here we evaluated the effects of lithium on proliferation, cell cycle and DNA damage after irradiation of young NSPCs in vitro.NSPCs were treated with 1 or 3 mM LiCl and we investigated proliferation capacity (neurosphere volume and bromodeoxyuridine (BrdU) incorporation). Using flow cytometry, we analysed apoptosis (annexin V), cell cycle (propidium iodide) and DNA damage (γH2AX) after irradiation (3.5 Gy) of lithium-treated NSPCs.Lithium increased BrdU incorporation and, dose-dependently, the number of cells in replicative phase as well as neurosphere growth. Irradiation induced cell cycle arrest in G1 and G2/M phases. Treatment with 3 mM LiCl was sufficient to increase NSPCs in S phase, boost neurosphere growth and reduce DNA damage. Lithium did not affect the levels of apoptosis, suggesting that it does not rescue NSPCs committed to apoptosis due to accumulated DNA damage.Lithium is a very promising candidate for protection of the juvenile brain from radiotherapy and for its potential to thereby improve the quality of life for those children who survive their cancer.

  12. Swelling and optical properties of Si{sub 3}N{sub 4} films irradiated in the electronic regime

    Energy Technology Data Exchange (ETDEWEB)

    Canut, B. [Institut des Nanotechnologies de Lyon, Universite de Lyon, Universite Claude Bernard Lyon 1, CNRS, UMR 5270, Domaine Scientifique de la Doua, F-69622 Villeurbanne (France)], E-mail: bruno.canut@insa-lyon.fr; Ayari, A. [Centre de Recherche en Nanofabrication et Nanocaracterisation, Universite de Sherbrooke (Canada); Dupuis, J.; Lemiti, M.; Fave, A. [Institut des Nanotechnologies de Lyon, Universite de Lyon, Universite Claude Bernard Lyon 1, CNRS, UMR 5270, Domaine Scientifique de la Doua, F-69622 Villeurbanne (France); Ramos, S. [Laboratoire de Physique de la Matiere Condensee et Nanostructures, Universite de Lyon, Universite Claude Bernard Lyon 1, CNRS, UMR 5586, Domaine Scientifique de la Doua, F-69622 Villeurbanne (France)

    2009-03-15

    Silicon nitride layers of 140 nm thickness were deposited on silicon wafers by low pressure chemical vapour deposition (LPCVD) and irradiated at GANIL with Pb ions of 110 MeV up to a maximum fluence of 4 x 10{sup 13} cm{sup -2}. As shown in a previous work these irradiation conditions, characterized by a predominant electronic slowing-down (S{sub e} = 19.3 keV nm{sup -1}), lead to damage creation and formation of etchable tracks in Si{sub 3}N{sub 4}. In the present study we investigated other radiation-induced effects like out of plane swelling and refractive index decrease. From profilometry, step heights as large as 50 nm were measured for samples irradiated at the highest fluences (>10{sup 13} cm{sup -2}). From optical spectroscopy, the minimum reflectivity of the target is shifted towards the high wavelengths at increasing fluences. These results evidence a concomitant decrease of density and refractive index in irradiated Si{sub 3}N{sub 4}. Additional measurements, performed by ellipsometry, are in full agreement with this interpretation.

  13. Protein oxidation and aggregation in UVA-irradiated Escherichia coli cells as signs of accelerated cellular senescence.

    Science.gov (United States)

    Bosshard, Franziska; Riedel, Kathrin; Schneider, Thomas; Geiser, Carina; Bucheli, Margarete; Egli, Thomas

    2010-11-01

    Solar disinfection (SODIS) is a simple drinking water treatment method that improves microbiological water quality where other means are unavailable. It makes use of the deleterious effect of solar irradiation on pathogenic microbes and viruses. A positive impact on health has been documented in several epidemiological studies. However, the molecular mechanisms damaging cells during this simple treatment are not yet fully understood. Here we show that protein damage is crucial in the process of inactivation by sunlight. Protein damages in UVA-irradiated Escherichia coli cells have been evaluated by an immunoblot method for carbonylated proteins and an aggregation assay based on semi-quantitative proteomics. A wide spectrum of structural and enzymatic proteins within the cell is affected by carbonylation and aggregation. Vital cellular functions like the transcription and translation apparatus, transport systems, amino acid synthesis and degradation, respiration, ATP synthesis, glycolysis, the TCA cycle, chaperone functions and catalase are targeted by UVA irradiation. The protein damage pattern caused by SODIS strongly resembles the pattern caused by reactive oxygen stress. Hence, sunlight probably accelerates cellular senescence and leads to the inactivation and finally death of UVA-irradiated cells.

  14. TH-C-12A-11: Target Correlation of a 3D Surface Surrogate for Left Breast Irradiation Using the Respiratory-Gated Deep-Inspiration Breath-Hold Technique

    Energy Technology Data Exchange (ETDEWEB)

    Rong, Y; Walston, S [A Quick, Ohio State University, Columbus, OH (United States)

    2014-06-15

    Purpose: To evaluate the use of 3D optical surface imaging as a new surrogate for respiratory motion gated deep-inspiration breath-hold (DIBH) technique for left breast cancer patients. Methods: Patients with left-sided breast cancer after lumpectomy or mastectomy were selected as candidates for DIBH technique for their external beam radiation therapy. Treatment plans were created on both free breathing (FB) and DIBH CTs to determine whether DIBH was beneficial in reducing heart doses. The Real-time Position Management (RPM) system was used to acquire patient's breathing trace during DIBH CT acquisition and treatment delivery. The reference 3D surface models from FB and DIBH CTs were generated and transferred to the “AlignRT” system for patient positioning and real-time treatment monitoring. MV Cine images were acquired for each beam as quality assurance for intra-fractional position verification. The chest wall excursions measured on these images were used to define the actual target position during treatment, and to investigate the accuracy and reproducibility of RPM and AlignRT. Results: Reduction in heart dose can be achieved for left-sided breast patients using DIBH. Results showed that RPM has poor correlation with target position, as determined by the MV Cine imaging. This indicates that RPM may not be an adequate surrogate in defining the breath-hold level when used alone. Alternatively, the AlignRT surface imaging demonstrated a better correlation with the actual CW excursion during DIBH. Both the vertical and magnitude real-time deltas (RTDs) reported by AlignRT can be used as the gating parameter, with a recommend threshold of ±3 mm and 5 mm, respectively. Conclusion: 3D optical surface imaging serves as a superior target surrogate for the left breast treatment when compared to RPM. Working together with the realtime MV Cine imaging, they ensure accurate patient setup and dose delivery, while minimizing the imaging dose to patients.

  15. Solar Irradiance Variability

    CERN Document Server

    Solanki, Sami K

    2012-01-01

    The Sun has long been considered a constant star, to the extent that its total irradiance was termed the solar constant. It required radiometers in space to detect the small variations in solar irradiance on timescales of the solar rotation and the solar cycle. A part of the difficulty is that there are no other constant natural daytime sources to which the Sun's brightness can be compared. The discovery of solar irradiance variability rekindled a long-running discussion on how strongly the Sun affects our climate. A non-negligible influence is suggested by correlation studies between solar variability and climate indicators. The mechanism for solar irradiance variations that fits the observations best is that magnetic features at the solar surface, i.e. sunspots, faculae and the magnetic network, are responsible for almost all variations (although on short timescales convection and p-mode oscillations also contribute). In spite of significant progress important questions are still open. Thus there is a debat...

  16. NSUF Irradiated Materials Library

    Energy Technology Data Exchange (ETDEWEB)

    Cole, James Irvin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The Nuclear Science User Facilities has been in the process of establishing an innovative Irradiated Materials Library concept for maximizing the value of previous and on-going materials and nuclear fuels irradiation test campaigns, including utilization of real-world components retrieved from current and decommissioned reactors. When the ATR national scientific user facility was established in 2007 one of the goals of the program was to establish a library of irradiated samples for users to access and conduct research through competitively reviewed proposal process. As part of the initial effort, staff at the user facility identified legacy materials from previous programs that are still being stored in laboratories and hot-cell facilities at the INL. In addition other materials of interest were identified that are being stored outside the INL that the current owners have volunteered to enter into the library. Finally, over the course of the last several years, the ATR NSUF has irradiated more than 3500 specimens as part of NSUF competitively awarded research projects. The Logistics of managing this large inventory of highly radioactive poses unique challenges. This document will describe materials in the library, outline the policy for accessing these materials and put forth a strategy for making new additions to the library as well as establishing guidelines for minimum pedigree needed to be included in the library to limit the amount of material stored indefinitely without identified value.

  17. Cellular Response to Irradiation

    Institute of Scientific and Technical Information of China (English)

    LIU Bo; YAN Shi-Wei

    2011-01-01

    To explore the nonlinear activities of the cellular signaling system composed of one transcriptional arm and one protein-interaction arm, we use an irradiation-response module to study the dynamics of stochastic interactions.It is shown that the oscillatory behavior could be described in a unified way when the radiation-derived signal and noise are incorporated.

  18. Wholesomeness of irradiated food

    Energy Technology Data Exchange (ETDEWEB)

    Raica, Nicholas; McDowell, Marion E.; Darby, William J.

    1963-01-15

    The wholesomeness of irradiated foods was evaluated in mice, rats, dogs, and monkeys over a 2-year period, or 4 generations. Data are presented on the effects of a diet containing radiation-processed foods on growth, reproduction, hematology, histopathology, carcinogenicity, and life span. (86 references) (C.H.)

  19. Irradiation-induced grain growth and defect evolution in nanocrystalline zirconia with doped grain boundaries.

    Science.gov (United States)

    Dey, Sanchita; Mardinly, John; Wang, Yongqiang; Valdez, James A; Holesinger, Terry G; Uberuaga, Blas P; Ditto, Jeff J; Drazin, John W; Castro, Ricardo H R

    2016-06-22

    Grain boundaries are effective sinks for radiation-induced defects, ultimately impacting the radiation tolerance of nanocrystalline materials (dense materials with nanosized grains) against net defect accumulation. However, irradiation-induced grain growth leads to grain boundary area decrease, shortening potential benefits of nanostructures. A possible approach to mitigate this is the introduction of dopants to target a decrease in grain boundary mobility or a reduction in grain boundary energy to eliminate driving forces for grain growth (using similar strategies as to control thermal growth). Here we tested this concept in nanocrystalline zirconia doped with lanthanum. Although the dopant is observed to segregate to the grain boundaries, causing grain boundary energy decrease and promoting dragging forces for thermally activated boundary movement, irradiation induced grain growth could not be avoided under heavy ion irradiation, suggesting a different growth mechanism as compared to thermal growth. Furthermore, it is apparent that reducing the grain boundary energy reduced the effectiveness of the grain boundary as sinks, and the number of defects in the doped material is higher than in undoped (La-free) YSZ.

  20. Development of annular targets for {sup 99}MO production.

    Energy Technology Data Exchange (ETDEWEB)

    Conner, C.; Lewandowski, E. F.; Snelgrove, J. L.; Liberatore, M. W.; Walker, D. E.; Wiencek, T. C.; McGann, D. J.; Hofman, G. L.; Vandegrift, G. F.

    1999-09-30

    The new annular target performed well during irradiation. The target is inexpensive and provides good heat transfer during irradiation. Based on these and previous tests, we conclude that targets with zirconium tubes and either nickel-plated or zinc-plated foils work well. We proved that we could use aluminum target tubes, which are much cheaper and easier to work with than the zirconium tubes. In aluminum target tubes nickel-plated fission-recoil barriers work well and prevent bonding of the foil to the new target tubes during irradiation. Also, zinc-plated and aluminum-foil barriers appear promising in anodized aluminum tubes. Additional tests are anticipated to address such issues as fission-recoil barrier thickness and uranium foil composition. Overall, however, the target was successful and will provide an inexpensive, efficient way to irradiate LEU metal foil for the production of {sup 99}Mo.

  1. Numerical simulation on attenuation of stress wave in copper target irradiated by intense laser%强激光诱导的应力波在靶板中衰减特性数值模拟

    Institute of Scientific and Technical Information of China (English)

    张兴权; 左立生; 余晓流; 戚晓利; 黄志来; 王彪; 段仕伟

    2014-01-01

    利用ABAQUS数值模拟软件对脉宽为ns量级的强激光诱导的应力波在铜靶中传播特性进行了模拟研究。建立了适合于高压高应变率下一维平面应力波在铜靶中传播的有限元分析模型,模拟了两种不同激光冲击波峰值压力诱导的应力波在铜靶中衰减的特性。结果显示,峰值压力为0.35 GPa和3.5 GPa下驱动的应力波在铜靶中的传播速度分别为4600 m/s,4000 m/s。峰值压力为3.5 GPa冲击波在靶体内诱导的应力波出现了弹性波和塑性波的双波结构。应力波峰值的衰减规律呈指数形式衰减。模拟计算的结果与理论和实验结果较为一致。%The code Abaqus/Explicit was employed to simulate on propagation of stress wave in a copper foil target, which was induced by intense laser with ns level width. A model was developed to simulate one dimensional planar stress wave propagation and attenuation, and its simulated model consisted of two kinds of elements: finite elements and infinite elements. Fine finite elements were used in laser shocked zone, and coarse infinite elements were used in surrounding zone as no reflecting boundaries. The strain rate effects and ultrahigh pressure effects on material yield stress were also considered. Series of simulations were performed using two different peak values, 0.35 GPa and 3.5 GPa, which were exerted on the target surface by shock wave. The two-step stress wave profile was obtained in copper target under the pressure of 3.5 GPa. The numerical results suggest that shock velocity is 4 600 m/s under the pressure of 0.35 GPa, and 4 000 m/s under the pressure of 3.5 GPa. The value of peak stress attenuates with the propagated distance in form of an exponential function. Some numerical results are in good agreement with the experimental results.

  2. ICRP Publication 84 of the ICRP. Pregnancy and medical irradiation; ICRP publication 84 de la CIPR. Grossesse et irradiation medicale

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    In this volume, the ICRP answers questions relative to medical irradiation of pregnant women, that without responses could lead to unappropriated behaviours. It gives the circumstances for a women to be irradiated, the radiation doses delivered by the radiological procedures for a diagnosis and for a therapy. The risks for the fetus and the woman are tackled, their part in the general risks of the pregnancy and the information to give to the future mother. (N.C.)

  3. Post irradiation test report of irradiated DUPIC simulated fuel

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Myung Seung; Jung, I. H.; Moon, J. S. and others

    2001-12-01

    The post-irradiation examination of irradiated DUPIC (Direct Use of Spent PWR Fuel in CANDU Reactors) simulated fuel in HANARO was performed at IMEF (Irradiated Material Examination Facility) in KAERI during 6 months from October 1999 to March 2000. The objectives of this post-irradiation test are i) the integrity of the capsule to be used for DUPIC fuel, ii) ensuring the irradiation requirements of DUPIC fuel at HANARO, iii) performance verification in-core behavior at HANARO of DUPIC simulated fuel, iv) establishing and improvement the data base for DUPIC fuel performance verification codes, and v) establishing the irradiation procedure in HANARO for DUPIC fuel. The post-irradiation examination performed are {gamma}-scanning, profilometry, density, hardness, observation the microstructure and fission product distribution by optical microscope and electron probe microanalyser (EPMA)

  4. Tritium release from neutron irradiated beryllium pebbles

    Energy Technology Data Exchange (ETDEWEB)

    Scaffidi-Argentina, F.; Werle, H. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Neutronenphysik und Reactortechnik

    1998-01-01

    One of the most important open issues related to beryllium for fusion applications refers to the kinetics of the tritium release as a function of neutron fluence and temperature. The EXOTIC-7 as well as the `Beryllium` experiments carried out in the HFR reactor in Petten are considered as the most detailed and significant tests for investigating the beryllium response under neutron irradiation. This paper reviews the present status of beryllium post-irradiation examinations performed at the Forschungszentrum Karlsruhe with samples from the above mentioned irradiation experiments, trying to elucidate the tritium release controlling processes. In agreement with previous studies it has been found that release starts at about 500-550degC and achieves a maximum at about 700-750degC. The observed release at about 500-550degC is probably due to tritium escaping from chemical traps, while the maximum release at about 700-750degC is due to tritium escaping from physical traps. The consequences of a direct contact between beryllium and ceramics during irradiation, causing tritium implanting in a surface layer of beryllium up to a depth of about 40 mm and leading to an additional inventory which is usually several times larger than the neutron-produced one, are also presented and the effects on the tritium release are discussed. (author)

  5. Radioprotection of targeted and bystander cells by methylproamine

    Energy Technology Data Exchange (ETDEWEB)

    Burdak-Rothkamm, Susanne [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom); Oxford University Hospitals, Cellular Pathology, Oxford (United Kingdom); Smith, Andrea; Lobachevsky, Pavel; Martin, Roger [Peter MacCallum Cancer Centre, Molecular Radiation Biology Laboratory, Melbourne (Australia); University of Melbourne, The Sir Peter MacCallum Department of Oncology, Melbourne (Australia); Prise, Kevin M. [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom)

    2014-09-23

    Radioprotective agents are of interest for application in radiotherapy for cancer and in public health medicine in the context of accidental radiation exposure. Methylproamine is the lead compound of a class of radioprotectors which act as DNA binding anti-oxidants, enabling the repair of transient radiation-induced oxidative DNA lesions. This study tested methylproamine for the radioprotection of both directly targeted and bystander cells. T98G glioma cells were treated with 15 μM methylproamine and exposed to {sup 137}Cs γ-ray/X-ray irradiation and He{sup 2+} microbeam irradiation. Radioprotection of directly targeted cells and bystander cells was measured by clonogenic survival or γH2AX assay. Radioprotection of directly targeted T98G cells by methylproamine was observed for {sup 137}Cs γ-rays and X-rays but not for He{sup 2+} charged particle irradiation. The effect of methylproamine on the bystander cell population was tested for both X-ray irradiation and He{sup 2+} ion microbeam irradiation. The X-ray bystander experiments were carried out by medium transfer from irradiated to non-irradiated cultures and three experimental designs were tested. Radioprotection was only observed when recipient cells were pretreated with the drug prior to exposure to the conditioned medium. In microbeam bystander experiments targeted and nontargeted cells were co-cultured with continuous methylproamine treatment during irradiation and postradiation incubation; radioprotection of bystander cells was observed. Methylproamine protected targeted cells from DNA damage caused by γ-ray or X-ray radiation but not He{sup 2+} ion radiation. Protection of bystander cells was independent of the type of radiation which the donor population received. (orig.) [German] Radioprotektive Agenzien sind sowohl in der Strahlentherapie von Krebserkrankungen als auch im Strahlenschutz im Zusammenhang mit akzidenteller Exposition von Bedeutung. Methylproamine ist die Leitsubstanz einer Klasse von

  6. Radiation target analysis of RNA.

    Science.gov (United States)

    Benstein, S L; Kempner, E

    1996-06-25

    Ribozymes are polynucleotide molecules with intrinsic catalytic activity, capable of cleaving nucleic acid substrates. Large RNA molecules were synthesized containing a hammerhead ribozyme moiety of 52 nucleotides linked to an inactive leader sequence, for total lengths of either 262 or 1226 nucleotides. Frozen RNAs were irradiated with high energy electrons. Surviving ribozyme activity was determined using the ability of the irradiated ribozymes to cleave a labeled substrate. The amount of intact RNA remaining was determined from the same irradiated samples by scanning the RNA band following denaturing gel electrophoresis. Radiation target analyses of these data revealed a structural target size of 80 kDa and a ribozyme activity target size of 15 kDa for the smaller ribozyme, and 319 kDa and 16 kDa, respectively, for the larger ribozyme. The disparity in target size for activity versus structure indicates that, in contrast to proteins, there is no spread of radiation damage far from the primary site of ionization in RNA molecules. The smaller target size for activity indicates that only primary ionizations occurring in the specific active region are effective. This is similar to the case for oligosaccharides. We concluded that the presence of the ribose sugar in the polymer chain restricts radiation damage to a small region and prevents major energy transfer throughout the molecule. Radiation target analysis should be a useful technique for evaluating local RNA:RNA and RNA:protein interactions in vitro.

  7. The radiation defect accumulation in scintillative crystals of caesium halides under intense electron beam irradiation

    CERN Document Server

    Galiy, P V

    1999-01-01

    The characteristics of defect accumulation and radiolysis at CsI crystals under mean energies of electron irradiation at wide dose rates and ranges of doses have been investigated by such methods: thermostimulated exoelectron emission (TSEE), Auger electron spectroscopy (AES) and optical absorption spectroscopy (OAS). The limit dose rates and absorbed doses of electron irradiation that lead to defects accumulation at room temperature in crystals volume and also surface stoichiometry violation have been evaluated. The doses of electron irradiation that lead to CsI radiolysis, with caesium coagulation in metallic phase have been determined. Some quasi periodic connection of such process with irradiation dose was observed.

  8. Systematic Study of the PbWO4 Crystal Short Term Instalibity Under Irradiation

    CERN Document Server

    Annenkov, Alexander; Chipaux, Rémi; Drobychev, Gleb; Fedorov, Andrey; Géléoc, Marie; Golubev, Nikolai; Korzhik, Mikhail; Lecoq, Paul; Ligun, A B; Missevitch, Oleg; Pavlenko, V B; Peigneux, Jean-Pierre; Singovsky, Alexander

    1997-01-01

    The effect of the irradiation on the lead tungstate ( PWO) scintillator properties has been studied at different irradiation facilities. Lead tungstate crystals grown with the tuning of oxides content in the melt to the stoichiometry of pure sheelite or sheelite-like type crystals and doped with heterovalent, trivalent and pentavalent impurities have been studied in order to optimize their resistance to irradiation. A combination of a selective cleaning of raw materials, a tuning of the melt from crystallization to crystallisation, and a destruction or compensation of the point structure defects has been used to minimize the short-term instability of PWO parameters under irradiation.

  9. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying

    Science.gov (United States)

    Semaltianos, N. G.; Chassagnon, R.; Moutarlier, V.; Blondeau-Patissier, V.; Assoul, M.; Monteil, G.

    2017-04-01

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  10. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying.

    Science.gov (United States)

    Semaltianos, N G; Chassagnon, R; Moutarlier, V; Blondeau-Patissier, V; Assoul, M; Monteil, G

    2017-04-18

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  11. Moving Target Defense

    CERN Document Server

    Jajodia, Sushil; Swarup, Vipin; Wang, Cliff; Wang, X Sean

    2011-01-01

    Moving Target Defense: Creating Asymmetric Uncertainty for Cyber Threats was developed by a group of leading researchers. It describes the fundamental challenges facing the research community and identifies new promising solution paths. Moving Target Defense which is motivated by the asymmetric costs borne by cyber defenders takes an advantage afforded to attackers and reverses it to advantage defenders. Moving Target Defense is enabled by technical trends in recent years, including virtualization and workload migration on commodity systems, widespread and redundant network connectivity, instr

  12. Neutronic performance of the MEGAPIE spallation target under high power proton beam

    Energy Technology Data Exchange (ETDEWEB)

    Michel-Sendis, F. [CEA - Saclay, Irfu/Service de Physique Nucleaire, F91191 Gif-sur-Yvette (France); Chabod, S. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, 38000 Grenoble (France); Letourneau, A. [CEA - Saclay, Irfu/Service de Physique Nucleaire, F91191 Gif-sur-Yvette (France); Panebianco, S., E-mail: stefano.panebianco@cea.f [CEA - Saclay, Irfu/Service de Physique Nucleaire, F91191 Gif-sur-Yvette (France); Zanini, L. [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2010-07-01

    The MEGAPIE project, aiming at the construction and operation of a megawatt liquid lead-bismuth spallation target, constitutes the first step in demonstrating the feasibility of liquid heavy metal target technologies as spallation neutron sources. In particular, MEGAPIE is meant to assess the coupling of a high power proton beam with a window-concept heavy liquid metal target. The experiment has been set at the Paul Scherrer Institute (PSI) in Switzerland and, after a 4-month long irradiation, has provided unique data for a better understanding of the behavior of such a target under realistic irradiation conditions. A complex neutron detector has been developed to provide an on-line measurement of the neutron fluency inside the target and close to the proton beam. The detector is based on micrometric fission chambers and activation foils. These two complementary detection techniques have provided a characterization of the neutron flux inside the target for different positions along its axis. Measurements and simulation results presented in this paper aim to provide important recommendations for future accelerator driven systems (ADS) and neutron source developments.

  13. Irradiated cocoa beans

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, R.; Tesh, J.M.

    1982-11-01

    Groups of 40 male and 40 female CD rats were fed powdered rodent diet containing 25% (w/w) of either non-irradiated, irradiated or fumigated cocoa beans. The diets were supplemented with certain essential dietary constituents designed to satisfy normal nutritional requirements. An additional 40 male and 40 female rats received basal rodent diet alone (ground) and acted as an untreated control. After 70 days of treatment, 15 male and 15 female rats from each group were used to assess reproductive function of the F/sub 0/ animals and growth and development of the F/sub 1/ offspring up to weaning; the remaining animals were killed after 91 days of treatment.

  14. Irradiated brown dwarfs

    CERN Document Server

    Casewell, S L; Lawrie, K A; Maxted, P F L; Dobbie, P D; Napiwotzki, R

    2014-01-01

    We have observed the post common envelope binary WD0137-349 in the near infrared $J$, $H$ and $K$ bands and have determined that the photometry varies on the system period (116 min). The amplitude of the variability increases with increasing wavelength, indicating that the brown dwarf in the system is likely being irradiated by its 16500 K white dwarf companion. The effect of the (primarily) UV irradiation on the brown dwarf atmosphere is unknown, but it is possible that stratospheric hazes are formed. It is also possible that the brown dwarf (an L-T transition object) itself is variable due to patchy cloud cover. Both these scenarios are discussed, and suggestions for further study are made.

  15. Target materials for exotic ISOL beams

    Science.gov (United States)

    Gottberg, A.

    2016-06-01

    The demand for intensity, purity, reliability and availability of short-lived isotopes far from stability is steadily high, and considerably exceeding the supply. In many cases the ISOL (Isotope Separation On-Line) method can provide beams of high intensity and purity. Limitations in terms of accessible chemical species and minimum half-life are driven mainly by chemical reactions and physical processes inside of the thick target. A wide range of materials are in use, ranging from thin metallic foils and liquids to refractory ceramics, while poly-phasic mixed uranium carbides have become the reference target material for most ISOL facilities world-wide. Target material research and development is often complex and especially important post-irradiation analyses are hindered by the high intrinsic radiotoxicity of these materials. However, recent achievements have proven that these investigations are possible if the effort of different facilities is combined, leading to the development of new material matrices that can supply new beams of unprecedented intensity and beam current stability.

  16. Increased efficacy of photodynamic therapy via sequential targeting

    Science.gov (United States)

    Kessel, David; Aggarwal, Neha; Sloane, Bonnie F.

    2014-03-01

    Photokilling depends on the generation of death signals after photosensitized cells are irradiated. A variety of intracellular organelles can be targeted for photodamage, often with a high degree of specificity. We have discovered that a low level of photodamage directed against lysosomes can sensitize both a murine hepatoma cell line (in 2D culture) and an inflammatory breast cancer line of human origin (in a 3D model) to subsequent photodamage directed at mitochondria. Additional studies were carried out with hepatoma cells to explore possible mechanisms. The phototoxic effect of the `sequential targeting' approach was associated with an increased apoptotic response. The low level of lysosomal photodamage did not lead to any detectable migration of Fe++ from lysosomes to mitochondria or increased reactive oxygen species (ROS) formation after subsequent mitochondrial photodamage. Instead, there appears to be a signal generated that can amplify the pro-apoptotic effect of subsequent mitochondrial photodamage.

  17. Down-Regulation of miR-129-5p and the let-7 Family in Neuroendocrine Tumors and Metastases Leads to Up-Regulation of Their Targets Egr1, G3bp1, Hmga2 and Bach1

    Directory of Open Access Journals (Sweden)

    Kristina B. V. Døssing

    2014-12-01

    Full Text Available Expression of miRNAs in Neuroendocrine Neoplasms (NEN is poorly characterized. We therefore wanted to examine the miRNA expression in Neuroendocrine Tumors (NETs, and identify their targets and importance in NET carcinogenesis. miRNA expression in six NEN primary tumors, six NEN metastases and four normal intestinal tissues was characterized using miRNA arrays, and validated by in-situ hybridization and qPCR. Among the down-regulated miRNAs miR-129-5p and the let-7f/let-7 family, were selected for further characterization. Transfection of miR-129-5p inhibited growth of a pulmonary and an intestinal carcinoid cell line. Analysis of mRNA expression changes identified EGR1 and G3BP1 as miR-129-5p targets. They were validated by luciferase assay and western blotting, and found robustly expressed in NETs by immunohistochemistry. Knockdown of EGR1 and G3BP1 mimicked the growth inhibition induced by miR-129-5p. let-7 overexpression inhibited growth of carcinoid cell lines, and let-7 inhibition increased protein content of the transcription factor BACH1 and its targets MMP1 and HMGA2, all known to promote bone metastases. Immunohistochemistry analysis revealed that let-7 targets are highly expressed in NETs and metastases. We found down-regulation of miR-129-5p and the let-7 family, and identified new neuroendocrine specific targets for these miRNAs, which contributes to the growth and metastatic potential of these tumors.

  18. Project Plan Remote Target Fabrication Refurbishment Project

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Gary L [ORNL; Taylor, Robin D [ORNL

    2009-08-01

    In early FY2009, the DOE Office of Science - Nuclear Physics Program reinstated a program for continued production of {sup 252}Cf and other transcurium isotopes at the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). The FY2009 major elements of the workscope are as follows: (1) Recovery and processing of seven transuranium element targets undergoing irradiation at the High Flux Isotope Reactor (HFIR) at ORNL; (2) Development of a plan to manufacture new targets for irradiation beginning in early- to mid-FY10 to supply irradiated targets for processing Campaign 75 (TRU75); and (3) Refurbishment of the target manufacturing equipment to allow new target manufacture in early FY10 The {sup 252}Cf product from processing Campaign 74 (recently processed and currently shipping to customers) is expected to supply the domestic demands for a period of approximately two years. Therefore it is essential that new targets be introduced for irradiation by the second quarter of FY10 (HFIR cycle 427) to maintain supply of {sup 252}Cf; the average irradiation period is {approx}10 HFIR cycles, requiring about 1.5 calendar years. The strategy for continued production of {sup 252}Cf depends upon repairing and refurbishing the existing pellet and target fabrication equipment for one additional target production campaign. This equipment dates from the mid-1960s to the late 1980s, and during the last target fabrication campaign in 2005- 2006, a number of component failures and operations difficulties were encountered. It is expected that following the target fabrication and acceptance testing of the targets that will supply material for processing Campaign 75 a comprehensive upgrade and replacement of the remote hot-cell equipment will be required prior to subsequent campaigns. Such a major refit could start in early FY 2011 and would take about 2 years to complete. Scope and cost estimates for the repairs described herein were developed, and

  19. On-line dosimetry for photodynamic therapy: part I--incident irradiance versus space irradiance for human skin

    Science.gov (United States)

    Radasky, Christine J.; Crean, David H.; Doiron, Daniel R.

    1996-04-01

    One of the key components of photodynamic therapy dosimetry studies is the actual light dose delivered to the tissue at a targeted, therapeutic depth. The light dose delivered to the tissue is dependent upon the incident irradiance at the initial point of light application as well as the tissue optical properties. Since the parameters defining the light and therapeutic dose may vary between subjects and treatment sites as well as during treatment, it is advantageous to monitor the dosimetry during photodynamic therapy. The objective of this work is to develop methodologies and systems to enable on-line dosimetry. This initial study examines the relationship between incident irradiance and space irradiance for cutaneous areas in various humans. Space irradiance levels (mW/cm2) were measured on the skin surface of 30 subjects using isotropic fiber optic probes (0.8 mm) and were compared to incident irradiance levels. Space irradiance values were obtained from various anatomical locations on each subject during surface illumination (664 plus or minus 7 nm) using an incident irradiance of 100 mW/cm2. The results demonstrate ratios of space irradiance: incident irradiance from 1.49 to 2.35 for all cutaneous areas. Abnormal skin features, such as scars, birthmarks, moles, freckles, etc., on the arm demonstrated ratios ranging from 1.58 to 1.84. Variances observed within and between subjects demonstrate the need for accurate dosimetry monitoring during therapy. A larger study is planned to fully characterize space irradiance variations in normal skin as well as cutaneous lesions in additional subjects.

  20. Understanding the Irradiation Behavior of Zirconium Carbide

    Energy Technology Data Exchange (ETDEWEB)

    Motta, Arthur [Pennsylvania State Univ., University Park, PA (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Szlufarska, Izabela [Univ. of Wisconsin, Madison, WI (United States)

    2013-10-11

    -induced microstructures mapped spatially and temporally, microstructural evolution during post-irradiation annealing, and atomistic modeling of defect formation and transport energetics will provide new, critical understanding about property changes in ZrC. The behavior of materials under irradiation is determined by the balance between damage production, defect clustering, and lattice response. In order to predict those effects at high temperatures so targeted testing can be expanded and extrapolated beyond the known database, it is necessary to determine the defect energetics and mobilities as these control damage accumulation and annealing. In particular, low-temperature irradiations are invaluable for determining the regions of defect mobility. Computer simulation techniques are particularly useful for identifying basic defect properties, especially if closely coupled with a well-constructed and complete experimental database. The close coupling of calculation and experiment in this project will provide mutual benchmarking and allow us to glean a deeper understanding of the irradiation response of ZrC, which can then be applied to the prediction of its behavior in reactor conditions.

  1. Development of new target concepts for proton beams at CERN/ISOLDE

    CERN Document Server

    Delonca, Melanie; Montavon, Ghislain; Peyraut, Francois

    More and more, the power of primary beam sent onto targets increases until reaching several kiloWatts of magnitude, inducing new problematic and challenges. Consequently, the need of new target design arises and leads to new conceptual design proposal. Amongst them, a concept of Lead Bismuth Eutectic (LBE) loop target making use of an heat exchanger (HEX) and a pump has been proposed during the European project EURISOL Design Study. This concept proposed an improvement in terms of release efficiency of short-lived species by transforming the irradiated liquid into droplets shape. This thesis presents the development of this target design proposal. A prototype target has been developed and will be tested under proton beam at ISOLDE at Cern, Geneva. Several analytical tools for the study of this kind of targets are proposed, taking into account different design parameters. These tools can be applied for other high power target concept and allow an easy dimensioning of this kind of targets. As well, an innovativ...

  2. A high irradiance solar furnace for solar cell characterization and nanomaterial synthesis

    Science.gov (United States)

    Babai, Dotan; Feuermann, Daniel; Gordon, Jeffrey M.

    2010-08-01

    A high irradiance solar furnace geared toward elucidating the distinctive physics of concentrator photovoltaics and driving high-temperature reactors for the generation of novel nanostructures is described, with a target irradiance up to 12 W/mm2. The opto-mechanical design permits real-sun flash illumination at a millisecond time scale so that solar cells can be characterized with only insubstantial increases in cell temperature even at irradiance levels of thousands of suns.

  3. Identification of irradiated refrigerated poultry with the DNA comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Villavicencio, A.L.C.H. E-mail: villavic@net.ipen.br; Araujo, M.M.; Marin-Huachaca, N.S.; Mancini-Filho, J. E-mail: jmancini@usp.br; Delincee, H. E-mail: henry.delincee@bfe.uni-karlsruhe.de

    2004-10-01

    Food irradiation could make a significant contribution to the reduction of food-borne diseases caused by harmful bacteria such as Salmonella and parasites. In fact these organisms cause an increasing number of diseases and eventually deaths all over the world, also in industrialized countries. Radiation processing has the advantage that in addition to eliminating pathogens, thereby enhancing food safety, it also extends shelf life through destruction of spoilage organisms. The DNA molecule because of its big size is an easy target for ionizing radiation, therefore, changes in DNA offer potential to be used as a detection method for the irradiation treatment. In our study, poultry has been irradiated and changes in DNA analyzed by the Comet Assay. Samples were packed in plastic bags and irradiated. Doses were 0, 1.5, 3.0 and 4.5 kGy. Immediately after irradiation the samples were returned to the refrigerator (4 deg. C). Samples were analyzed 1 and 10 days after irradiation. This method proved to be an inexpensive and rapid screening technique for qualitative detection of irradiation treatment.

  4. Identification of irradiated refrigerated poultry with the DNA comet assay

    Science.gov (United States)

    Villavicencio, A. L. C. H.; Araújo, M. M.; Marin-Huachaca, N. S.; Mancini-Filho, J.; Delincée, H.

    2004-09-01

    Food irradiation could make a significant contribution to the reduction of food-borne diseases caused by harmful bacteria such as Salmonella and parasites. In fact these organisms cause an increasing number of diseases and eventually deaths all over the world, also in industrialized countries. Radiation processing has the advantage that in addition to eliminating pathogens, thereby enhancing food safety, it also extends shelf life through destruction of spoilage organisms. The DNA molecule because of its big size is an easy target for ionizing radiation, therefore, changes in DNA offer potential to be used as a detection method for the irradiation treatment. In our study, poultry has been irradiated and changes in DNA analyzed by the Comet Assay. Samples were packed in plastic bags and irradiated. Doses were 0, 1.5, 3.0 and 4.5kGy. Immediately after irradiation the samples were returned to the refrigerator (4°C). Samples were analyzed 1 and 10 days after irradiation. This method proved to be an inexpensive and rapid screening technique for qualitative detection of irradiation treatment.

  5. Research Advances: DNA Computing Targets West Nile Virus, Other Deadly Diseases, and Tic-Tac-Toe; Marijuana Component May Offer Hope for Alzheimer's Disease Treatment; New Wound Dressing May Lead to Maggot Therapy--Without the Maggots

    Science.gov (United States)

    King, Angela G.

    2007-01-01

    This article presents three reports of research advances. The first report describes a deoxyribonucleic acid (DNA)-based computer that could lead to faster, more accurate tests for diagnosing West Nile Virus and bird flu. Representing the first "medium-scale integrated molecular circuit," it is the most powerful computing device of its type to…

  6. Establishment of technical prerequisites for cell irradiation experiments with laser-accelerated electrons.

    Science.gov (United States)

    Beyreuther, E; Enghardt, W; Kaluza, M; Karsch, L; Laschinsky, L; Lessmann, E; Nicolai, M; Pawelke, J; Richter, C; Sauerbrey, R; Schlenvoigt, H P; Baumann, M

    2010-04-01

    In recent years, laser-based acceleration of charged particles has rapidly progressed and medical applications, e.g., in radiotherapy, might become feasible in the coming decade. Requirements are monoenergetic particle beams with long-term stable and reproducible properties as well as sufficient particle intensities and a controlled delivery of prescribed doses at the treatment site. Although conventional and laser-based particle accelerators will administer the same dose to the patient, their different time structures could result in different radiobiological properties. Therefore, the biological response to the ultrashort pulse durations and the resulting high peak dose rates of these particle beams have to be investigated. The technical prerequisites, i.e., a suitable cell irradiation setup and the precise dosimetric characterization of a laser-based particle accelerator, have to be realized in order to prepare systematic cell irradiation experiments. The Jena titanium:sapphire laser system (JETI) was customized in preparation for cell irradiation experiments with laser-accelerated electrons. The delivered electron beam was optimized with regard to its spectrum, diameter, dose rate, and dose homogeneity. A custom-designed beam and dose monitoring system, consisting of a Roos ionization chamber, a Faraday cup, and EBT-1 dosimetry films, enables real-time monitoring of irradiation experiments and precise determination of the dose delivered to the cells. Finally, as proof-of-principle experiment cell samples were irradiated using this setup. Laser-accelerated electron beams, appropriate for in vitro radiobiological experiments, were generated with a laser shot frequency of 2.5 Hz and a pulse length of 80 fs. After laser acceleration in the helium gas jet, the electrons were filtered by a magnet, released from the vacuum target chamber, and propagated in air for a distance of 220 mm. Within this distance a lead collimator (aperture of 35 mm) was introduced, leading

  7. Updated Results of Ultrasonic Transducer Irradiation Test

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua; Palmer, Joe [Idaho National Laboratory, P.O. Box 1625, MS 4112, Idaho Falls, ID, 38415-3840 (United States); Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert [Pacific Northwest National Laboratory, 902 Battelle Blvd. Richland, WA, 99354 (United States); Chien, Hual-Te [Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL, 60439 (United States); Tittmann, Bernhard; Reinhardt, Brian [Pennsylvania State University, 212 Earth and Engr. Sciences Building, University Park, PA, 16802 (United States); Kohse, Gordon [Massachusetts Institute of Technology, 77 Massachusetts Ave. Cambridge, MA 02139 (United States); Rempe, Joy [Rempe and Associates, LLC, 360 Stillwater, Idaho Falls, ID 83404 (United States); Villard, J.F. [Commissariat a l' energie atomique et aux energies alternatives, Centre d' etudes de Cadarache, 13108 Saint-Paul-lez-Durance (France)

    2015-07-01

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10{sup 21} n/cm{sup 2}. A multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET-ASI) program also provided initial support for this effort. This irradiation, which started in February 2014, is an instrumented lead test and real-time transducer performance data are collected along with temperature and neutron and gamma flux data. The irradiation is ongoing and will continue to approximately mid-2015. To date, very encouraging results have been attained as several transducers continue to operate under irradiation. (authors)

  8. TMAP7 simulations of deuterium trapping in pre-irradiated tungsten exposed to high-flux plasma

    NARCIS (Netherlands)

    Wright, G. M.; Mayer, M.; Ertl, K.; de Saint-Aubinc, G.; Rapp, J.

    2011-01-01

    Tungsten targets are irradiated with 12.3 MeV W4+ ions to damage levels up to 2.0 displacements per atom. These irradiated targets are then exposed to high-flux deuterium plasmas with surface temperatures ranging from 360 to 950 K. Nuclear reaction analysis shows significant enhancement of retention

  9. Low-oxygen atmospheric treatment improves the performance of irradiation-sterilized male cactus moths used in SIT.

    Science.gov (United States)

    As part of Sterile Insect Technique (SIT) programs, irradiation can effectively induce sterility in insects by damaging genomic DNA. However, irradiation also induces other off-target side effects that reduce the quality and performance of sterilized males. Thus, treatments that reduce off-target ef...

  10. Transgenerational developmental effects and genomic instability after X-irradiation of preimplantation embryos: Studies on two mouse strains

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, P., E-mail: pjacquet@sckcen.be [Molecular and Cellular Biology, Institute for Environment, Health and Safety, SCK.CEN, Boeretang 200, B-2400 Mol (Belgium); Buset, J.; Neefs, M. [Molecular and Cellular Biology, Institute for Environment, Health and Safety, SCK.CEN, Boeretang 200, B-2400 Mol (Belgium); Vankerkom, J. [Division of Environmental Research, VITO, Boeretang 200, B-2400 Mol (Belgium); Benotmane, M.A.; Derradji, H. [Molecular and Cellular Biology, Institute for Environment, Health and Safety, SCK.CEN, Boeretang 200, B-2400 Mol (Belgium); Hildebrandt, G. [Department of Radiotherapy and Radiation Oncology, University of Leipzig, Stephanstrasse 9a, D-04103 Leipzig (Germany); Department of Radiotherapy, University of Rostock, Suedring 75, D-18059 Rostock (Germany); Baatout, S. [Molecular and Cellular Biology, Institute for Environment, Health and Safety, SCK.CEN, Boeretang 200, B-2400 Mol (Belgium)

    2010-05-01

    Recent results have shown that irradiation of a single cell, the zygote or 1-cell embryo of various mouse strains, could lead to congenital anomalies in the fetuses. In the Heiligenberger strain, a link between the radiation-induced congenital anomalies and the development of a genomic instability was also suggested. Moreover, further studies showed that in that strain, both congenital anomalies and genomic instability could be transmitted to the next generation. The aim of the experiments described in this paper was to investigate whether such non-targeted transgenerational effects could also be observed in two other radiosensitive mouse strains (CF1 and ICR), using lower radiation doses. Irradiation of the CF1 and ICR female zygotes with 0.2 or 0.4 Gy did not result in a decrease of their fertility after birth, when they had reached sexual maturity. Moreover, females of both strains that had been X-irradiated with 0.2 Gy exhibited higher rates of pregnancy, less resorptions and more living fetuses. Additionally, the mean weight of living fetuses in these groups had significantly increased. Exencephaly and dwarfism were observed in CF1 fetuses issued from control and X-irradiated females. In the control group of that strain, polydactyly and limb deformity were also found. The yields of abnormal fetuses did not differ significantly between the control and X-irradiated groups. Polydactyly, exencephaly and dwarfism were observed in fetuses issued from ICR control females. In addition to these anomalies, gastroschisis, curly tail and open eye were observed at low frequencies in ICR fetuses issued from X-irradiated females. Again, the frequencies of abnormal fetuses found in the different groups did not differ significantly. In both CF1 and ICR mouse strains, irradiation of female zygotes did not result in the development of a genomic instability in the next generation embryos. Overall, our results suggest that, at the moderate doses used, developmental defects

  11. ATF Neutron Irradiation Program Irradiation Vehicle Design Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Geringer, J. W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Cetiner, N. O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Petrie, Christian M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Smith, Kurt R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; McDuffee, J. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-03-01

    The Japan Atomic Energy Agency (JAEA) under the Civil Nuclear Energy Working Group (CNWG) is engaged in a cooperative research effort with the U.S. Department of Energy (DOE) to explore issues related to nuclear energy, including research on accident-tolerant fuels and materials for use in light water reactors. This work develops a draft technical plan for a neutron irradiation program on the candidate accident-tolerant fuel cladding materials and elements using the High Flux Isotope Reactor (HFIR). The research program requires the design of a detailed experiment, development of test vehicles, irradiation of test specimens, possible post irradiation examination and characterization of irradiated materials and the shipment of irradiated materials to Japan. This report discusses the conceptual design, the development and irradiation of the test vehicles.

  12. Pharmacokinetics and pharmacodynamics utilizing unbound target tissue exposure as part of a disposition-based rationale for lead optimization of benzoxaboroles in the treatment of Stage 2 Human African Trypanosomiasis.

    Science.gov (United States)

    Wring, Stephen; Gaukel, Eric; Nare, Bakela; Jacobs, Robert; Beaudet, Beth; Bowling, Tana; Mercer, Luke; Bacchi, Cyrus; Yarlett, Nigel; Randolph, Ryan; Parham, Robin; Rewerts, Cindy; Platner, Jacob; Don, Robert

    2014-01-01

    SUMMARY This review presents a progression strategy for the discovery of new anti-parasitic drugs that uses in vitro susceptibility, time-kill and reversibility measures to define the therapeutically relevant exposure required in target tissues of animal infection models. The strategy is exemplified by the discovery of SCYX-7158 as a potential oral treatment for stage 2 (CNS) Human African Trypanosomiasis (HAT). A critique of current treatments for stage 2 HAT is included to provide context for the challenges of achieving target tissue disposition and the need for establishing pharmacokinetic-pharmacodynamic (PK-PD) measures early in the discovery paradigm. The strategy comprises 3 stages. Initially, compounds demonstrating promising in vitro activity and selectivity for the target organism over mammalian cells are advanced to in vitro metabolic stability, barrier permeability and tissue binding assays to establish that they will likely achieve and maintain therapeutic concentrations during in-life efficacy studies. Secondly, in vitro time-kill and reversibility kinetics are employed to correlate exposure (based on unbound concentrations) with in vitro activity, and to identify pharmacodynamic measures that would best predict efficacy. Lastly, this information is used to design dosing regimens for pivotal pharmacokinetic-pharmacodyamic studies in animal infection models.

  13. Gemstone dedicated gamma irradiation development

    Energy Technology Data Exchange (ETDEWEB)

    Omi, Nelson M.; Rela, Paulo R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: nminoru@ipen.br; prela@ipen.br

    2007-07-01

    The gemstones gamma irradiation process to enhance the color is widely accepted for the jewelry industry. These gems are processed in conventional industrial gamma irradiation plant which are optimized for other purposes, using underwater irradiation devices with high rejection rate due to its poor dose uniformity. A new conception design, which states the working principles and manufacturing ways of the device, was developed in this work. The suggested device's design is based on the rotation of cylindrical baskets and their translation in circular paths inside and outside a cylindrical source rack as a planetary system. The device is meant to perform the irradiation in the bottom of the source storage pool, where the sources remain always shielded by the water layer. The irradiator matches the Category III IAEA classification. To verify the physical viability of the basic principle, tests with rotating cylindrical baskets were performed in the Multipurpose Irradiator constructed in the CTR, IPEN. Also, simulations using the CADGAMMA software, adapted to simulate underwater irradiations, were performed. With the definitive optimized irradiator, the irradiation quality will be enhanced with better dose control and the production costs will be significantly lower than market prices due to the intended treatment device's optimization. This work presents some optimization parameters and the expected performance of the irradiator. (author)

  14. The application of high dose food irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bruyn, I. De [Atomic Energy Corporation of South Africa LTD, Building 2000, P.O. Box 582, Pretoria 0001, (South Africa)

    1997-12-31

    During the 1950`s to end 1970`s the United States Army developed the basic methodology to produce shelf stable irradiated meat, seafood and poultry products. These products are normally packed without gravy, sauce or brine, as liquid is not required to sterilize the product as in the canning process. This leads to the distinctive `dried cooked` taste normally associated with roasts opposed to the casserole taste usually associated with tinned meats. The meats are cooked, chilled, portioned, vacuum packed and irradiated to the required minimum dose of 25 to 45 kGy (depending on the product) at a temperature of between -20 and -40 Centigrade to ensure absolute sterility even under tropical conditions. The product is packaged in a high quality four layer laminate pouch and will therefore not rust or burst even under adverse weather conditions. The product can be guaranteed for more than two years as long as the integrity of the packaging is maintained. (Author)

  15. Ion irradiation induced direct damage to DNA

    CERN Document Server

    Wang, Wei; Su, Wenhui

    2008-01-01

    Ion beams have been widely applied in a few biological research fields such as radioactive breeding, health protection, and tumor therapy. Up to now many interesting and impressive achievements in biology and agriculture have been made. Over the past several decades, scientists in biology, physics, and chemistry have pursued investigations focused on understanding the mechanisms of these radiobiological effects of ion beams. From the chemical point of view, these effects are due to the ion irradiation induced biomolecular damage, direct or indirect. In this review, we will present a chemical overview of the direct effects of ion irradiation upon DNA and its components, based on a review of literature combined with recent experimental results. It is suggested that, under ion bombardment, a DNA molecule undergoes a variety of processes, including radical formation, atomic displacement, intramolecular bond-scissions, emission of fragments, fragment recombination and molecular crosslink, which may lead to genetic...

  16. Irradiation Effect of γ Rays on Diamond-Like Carbon Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Diamond-like carbon films, prepared by RF glow discharge on glasssubstrates, were irradiated by γ rays. The as-deposited and irradiated films were characterized by Raman spectroscopy, electrical resistivity, and infrared transmittance. It is shown that the irradiation of the γ rays can lead to the breaking of SP3C-H and SP2C-H bonds, slight increasing of SP3C-C bonds, and induced hydrogen recombination with H2 molecules, subsequently diffusing to the surface of the films. When the γ rays irradiation dose reached 10×104 Gy, the numbers of SP3C-H bonds was decreased by about 50%, the resistivity of irradiated DLC films was increased, and the diamond-like character of the films became more obvious. The structure of DLC films was modified when irradiated by γ rays. The irradiation mechanisms are briefly discussed.

  17. Energy Penetration into Arrays of Aligned Nanowires Irradiated with Relativistic Intensities: Scaling to Terabar Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Bargsten, Clayton [Colorado State Univ., Fort Collins, CO (United States); Hollinger, Reed [Colorado State Univ., Fort Collins, CO (United States); Capeluto, Maria Gabriela [Univ. of Buenos Aires (Argentina); Kaymak, Vural [Heinrich Heine Univ., Dusseldorf (Germany); Pukhov, Alexander [Heinrich Heine Univ., Dusseldorf (Germany); Wang, Shoujun [Colorado State Univ., Fort Collins, CO (United States); Rockwood, Alex [Colorado State Univ., Fort Collins, CO (United States); Wang, Yong [Colorado State Univ., Fort Collins, CO (United States); Keiss, David [Colorado State Univ., Fort Collins, CO (United States); Tommasini, Riccardo [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); London, Richard [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, Jaebum [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Busquet, Michel [ARTEP Inc., Ellicott City, MD (United States); Klapisch, M [ARTEP Inc., Ellicott City, MD (United States); Shlyaptsev, Vyacheslav N. [Colorado State Univ., Fort Collins, CO (United States); Rocca, Jorge J. [Colorado State Univ., Fort Collins, CO (United States)

    2016-11-11

    Ultra-high-energy-density (UHED) matter, characterized by energy densities > 1 x 108 J cm-3 and pressures greater than a gigabar, is encountered in the center of stars and in inertial confinement fusion capsules driven by the world’s largest lasers. Similar conditions can be obtained with compact, ultra-high contrast, femtosecond lasers focused to relativistic intensities onto targets composed of aligned nanowire arrays. Here we report the measurement of the key physical process in determining the energy density deposited in high aspect ratio nanowire array plasmas: the energy penetration. By monitoring the x-ray emission from buried Co tracer segments in Ni nanowire arrays irradiated at an intensity of 4 x 1019 W cm-2, we demonstrate energy penetration depths of several μm, leading to UHED plasmas of that size. Relativistic 3D particle-in-cell-simulations, validated by these measurements, predict that irradiation of nanostructures at intensities of > 1 x 1022 W cm-2 will lead to a virtually unexplored extreme UHED plasma regime characterized by energy densities in excess of 8 x 1010 J cm-3, equivalent to a pressure of 0.35 Tbar.

  18. Energy penetration into arrays of aligned nanowires irradiated with relativistic intensities: Scaling to terabar pressures

    Science.gov (United States)

    Bargsten, Clayton; Hollinger, Reed; Capeluto, Maria Gabriela; Kaymak, Vural; Pukhov, Alexander; Wang, Shoujun; Rockwood, Alex; Wang, Yong; Keiss, David; Tommasini, Riccardo; London, Richard; Park, Jaebum; Busquet, Michel; Klapisch, Marcel; Shlyaptsev, Vyacheslav N.; Rocca, Jorge J.

    2017-01-01

    Ultrahigh-energy density (UHED) matter, characterized by energy densities >1 × 108 J cm−3 and pressures greater than a gigabar, is encountered in the center of stars and inertial confinement fusion capsules driven by the world’s largest lasers. Similar conditions can be obtained with compact, ultrahigh contrast, femtosecond lasers focused to relativistic intensities onto targets composed of aligned nanowire arrays. We report the measurement of the key physical process in determining the energy density deposited in high-aspect-ratio nanowire array plasmas: the energy penetration. By monitoring the x-ray emission from buried Co tracer segments in Ni nanowire arrays irradiated at an intensity of 4 × 1019 W cm−2, we demonstrate energy penetration depths of several micrometers, leading to UHED plasmas of that size. Relativistic three-dimensional particle-in-cell simulations, validated by these measurements, predict that irradiation of nanostructures at intensities of >1 × 1022 W cm−2 will lead to a virtually unexplored extreme UHED plasma regime characterized by energy densities in excess of 8 × 1010 J cm−3, equivalent to a pressure of 0.35 Tbar. PMID:28097218

  19. Energy penetration into arrays of aligned nanowires irradiated with relativistic intensities: Scaling to terabar pressures.

    Science.gov (United States)

    Bargsten, Clayton; Hollinger, Reed; Capeluto, Maria Gabriela; Kaymak, Vural; Pukhov, Alexander; Wang, Shoujun; Rockwood, Alex; Wang, Yong; Keiss, David; Tommasini, Riccardo; London, Richard; Park, Jaebum; Busquet, Michel; Klapisch, Marcel; Shlyaptsev, Vyacheslav N; Rocca, Jorge J

    2017-01-01

    Ultrahigh-energy density (UHED) matter, characterized by energy densities >1 × 10(8) J cm(-3) and pressures greater than a gigabar, is encountered in the center of stars and inertial confinement fusion capsules driven by the world's largest lasers. Similar conditions can be obtained with compact, ultrahigh contrast, femtosecond lasers focused to relativistic intensities onto targets composed of aligned nanowire arrays. We report the measurement of the key physical process in determining the energy density deposited in high-aspect-ratio nanowire array plasmas: the energy penetration. By monitoring the x-ray emission from buried Co tracer segments in Ni nanowire arrays irradiated at an intensity of 4 × 10(19) W cm(-2), we demonstrate energy penetration depths of several micrometers, leading to UHED plasmas of that size. Relativistic three-dimensional particle-in-cell simulations, validated by these measurements, predict that irradiation of nanostructures at intensities of >1 × 10(22) W cm(-2) will lead to a virtually unexplored extreme UHED plasma regime characterized by energy densities in excess of 8 × 10(10) J cm(-3), equivalent to a pressure of 0.35 Tbar.

  20. Energy Density in Aligned Nanowire Arrays Irradiated with Relativistic Intensities: Path to Terabar Pressure Plasmas

    Science.gov (United States)

    Rocca, J.; Bargsten, C.; Hollinger, R.; Shylaptsev, V.; Wang, S.; Rockwood, A.; Wang, Y.; Keiss, D.; Capeluto, M.; Kaymak, V.; Pukhov, A.; Tommasini, R.; London, R.; Park, J.

    2016-10-01

    Ultra-high-energy-density (UHED) plasmas, characterized by energy densities >1 x 108 J cm-3 and pressures greater than a gigabar are encountered in the center of stars and in inertial confinement fusion capsules driven by the world's largest lasers. Similar conditions can be obtained with compact, ultra-high contrast, femtosecond lasers focused to relativistic intensities onto aligned nanowire array targets. Here we report the measurement of the key physical process in determining the energy density deposited in high aspect ratio nanowire array plasmas: the energy penetration. By monitoring the x-ray emission from buried Co tracer segments in Ni nanowire arrays irradiated at an intensity of 4 x 1019 W cm-2, we demonstrate energy penetration depths of several μm, leading to UHED plasmas of that size. Relativistic 3D particle-in-cell-simulations validated by these measurements predict that irradiation of nanostructures at increased intensity will lead to a virtually unexplored extreme UHED plasma regime characterized by energy densities in excess of 8 x 1010 J cm-3, equivalent to a pressure of 0.35 Tbar. This work was supported by the Fusion Energy Program, Office of Science of the U.S Department of Energy, and by the Defense Threat Reduction Agency.