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Sample records for gamma-ray irradiated elastomer

  1. Detecting onset of chain scission and crosslinking of gamma-ray irradiated elastomer surfaces using frictional force microscopy

    CERN Document Server

    Banerjee, S; Gayathri, N; Ponraju, D; Dash, S; Tyagi, A K; Raj, B; Raj, Baldev

    2005-01-01

    We report here that atomic force microscope (AFM) in frictional force mode can be used to detect onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers: (1) Ethylene-propylene-diene monomer rubber (EPDM) and (2) Fluorocarbon rubber (FKM) upon gamma-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the gamma-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behavior of increase in its frictional property has been attributed to the onset of chain scission and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes obse...

  2. Operating experience with gamma ray irradiators

    International Nuclear Information System (INIS)

    The experience of Atomic Energy of Canada, Limited (AECL) with radioisotopes dates back to the mid-1940s when radium was marketed for medical purposes. Cobalt-60 came on the scene in 1949 and within a few years a thriving business in cancer teletherapy machines and research irradiators was developed. AECL's first full-scale cobalt-60 gamma ray sterilizer for medical products was installed in 1964. AECL now has over 50 plants and 30 million curies in service around the world. Sixteen years of design experience in cobalt-60 sources, radiation shielding, safety interlock systems, and source pass mechanisms have made gamma irradiators safe, reliable, and easy to operate. This proven technology is being applied in promising new fields such as sludge treatment and food preservation. Cesium-137 is expected to be extensively utilized as the gamma radiation source for these applications

  3. Gamma-ray spectroscopy on irradiated fuel rods

    International Nuclear Information System (INIS)

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  4. Gamma-ray spectroscopy on irradiated fuel rods

    Energy Technology Data Exchange (ETDEWEB)

    Terremoto, Luis Antonio Albiac [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear], e-mail: laaterre@ipen.br

    2009-07-01

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  5. Effect of gamma ray irradiation on sodium borate single crystals

    Science.gov (United States)

    Kalidasan, M.; Asokan, K.; Baskar, K.; Dhanasekaran, R.

    2015-12-01

    In this work, the effects of 5 kGy, 10 kGy and 20 kGy doses of gamma ray irradiation on sodium borate, Na2[B4O5(OH)4](H2O)8 single crystals have been studied. Initially these crystals were grown by solution growth technique and identified as monoclinic using X-ray diffraction analysis. X-ray rocking curves confirm the formation of crystalline defects due to gamma rays in sodium borate single crystals. The electron paramagnetic resonance spectra have been recorded to identify the radicals created due to gamma ray irradiation in sodium borate single crystals. The thermoluminescence glow curves due to the defects created by gamma rays in this crystal have been observed and their kinetic parameters were calculated using Chen's peak shape method. The optical absorption increases and photoluminescence spectral intensity decreases for 5 kGy and 20 kGy doses gamma ray irradiated crystals compared to pristine and 10 kGy dose irradiated one. The effect of various doses of gamma rays on vibrational modes of the sodium borate single crystals was studied using FT-Raman and ATR-FTIR spectral analysis. The dielectric permittivity, conductance and dielectric loss versus frequency graphs of these crystals have been analyzed to know the effect of gamma ray irradiation on these parameters.

  6. Effects of gamma ray irradiation on sensitivity of photochromic glasses

    International Nuclear Information System (INIS)

    Photochromic glasses exposed to certain amount of gamma rays in advance of heat treatment show much higher photosensitivity than non-irradiated glasses. It was clarified that the crystal size of AgCl formed in the glass during the heat treatment shifted smaller, and that the number of the crystals in unit volume increased with increasing gamma irradiation dose. Size and number density of the AgCl crystals in the sample glasses are observed by electron microscope and X-ray diffraction method. The effects of gamma ray irradiation are possibly explained that gamma ray produces nuclei, each of which grows into AgCl crystal during the subsequent heat treatment. Photoabsorption spectrum of each photochromic glass sample exposed to visible light was observed, and it shows that the wavelength of absorption peak depends on gamma ray irradiation dose. (auth.)

  7. Inactivation of citrus tristeza virus by gamma ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ieki, Hiroyuki; Yamaguchi, Akira

    1984-12-01

    The total exposure of gamma ray and the intensity of gamma ray per hour for the inactivation of citrus tristeza virus (CTV) and also the effect on citrus tissues are described. The budwoods of Morita navel orange infected with a severe seedling-yellow strain of CTV were irradiated with gamma ray from a /sup 60/Co source for 20 - 52 hours. The buds or small tissue pieces of the irradiated budwoods were subsequently grafted onto Mexcan lime. CTV was easily inactivated by the irradiation from 10 to 18 kR for from 20 to 52 hours. The higher the total exposure, the higher the rate of inactivation. The CTV in the budwoods was almost inactivated after the irradiation with 20 kR. When the total exposure to gamma ray on budwoods was the same, CTV was more efficiently inactivated by the irradiation for long period with low intensity of gamma ray per hour than that for short period with high intensity per hour. Gamma ray irradiation was effective to eliminate CTV from citrus tissues. (Mori, K.).

  8. Inactivation of citrus tristeza virus by gamma ray irradiation

    International Nuclear Information System (INIS)

    The total exposure of gamma ray and the intensity of gamma ray per hour for the inactivation of citrus tristeza virus (CTV) and also the effect on citrus tissues are described. The budwoods of Morita navel orange infected with a severe seedling-yellow strain of CTV were irradiated with gamma ray from a 60Co source for 20 -- 52 hours. The buds or small tissue pieces of the irradiated budwoods were subsequently grafted onto Mexcan lime. CTV was easily inactivated by the irradiation from 10 to 18 kR for from 20 to 52 hours. The higher the total exposure, the higher the rate of inactivation. The CTV in the budwoods was almost inactivated after the irradiation with 20 kR. When the total exposure to gamma ray on budwoods was the same, CTV was more efficiently inactivated by the irradiation for long period with low intensity of gamma ray per hour than that for short period with high intensity per hour. Gamma ray irradiation was effective to eliminate CTV from citrus tissues. (Mori, K.)

  9. Gamma ray irradiation to semi-purified diet

    International Nuclear Information System (INIS)

    Semi-purified diet containing 10% soybean oil was irradiated with gamma rays at levels of 0.6, 3 and 6 Mrad and was fed to chicks. Crude fat contents of the diets decreased and a considerable amount of peroxide was formed with high doses of irradiation. Feed consumption and feed efficiency of the highly irradiated diets were less than those of control. Metabolizable energy and digestibility of the diets, especially of fat, were decreased with the irradiation. The chicks fed with irradiated diets showed marked dilatation of the small intestine and the liver, and their erythrocytes were more fragile than those of control. The same phenomena were found with the chicks fed the diet containing the oil highly oxidized by autoxidation. Irradiation of the diet excluding oil showed little effect on the growth of chicks. It was considered that these phenomena were caused by the peroxide or other oxidation products of fat which were formed with gamma ray irradiation. (auth.)

  10. Influence of gamma ray irradiation on metakaolin based sodium geopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Lambertin, D., E-mail: david.lambertin@cea.fr [CEA, DEN, DTCD/SPDE/LP2C, F-30207 Bagnols-sur-Cze (France); Boher, C. [CEA, DEN, DTCD/SPDE/LP2C, F-30207 Bagnols-sur-Cze (France); Dannoux-Papin, A. [CEA, DEN, DTCD/SPDE/LCFI, F-30207 Bagnols-sur-Cze (France); Galliez, K.; Rooses, A.; Frizon, F. [CEA, DEN, DTCD/SPDE/LP2C, F-30207 Bagnols-sur-Cze (France)

    2013-11-15

    Effects of gamma irradiation on metakaolin based Na-geopolymer have been investigated by external irradiation. The experiments were carried out in a gamma irradiator with {sup 60}Co sources up to 1000 kGy. Various Na-geopolymer with three H{sub 2}O/Na{sub 2}O ratios have been studied in terms of hydrogen radiolytic yield. The results show that hydrogen production increases linearly with water content. Gamma irradiation effects on Na-geopolymer microstructure have been investigated with porosity measurements and X-ray pair distribution function analysis. A change of pore size distribution and a structural relaxation have been found after gamma ray irradiation.

  11. Influence of gamma ray irradiation on metakaolin based sodium geopolymer

    Science.gov (United States)

    Lambertin, D.; Boher, C.; Dannoux-Papin, A.; Galliez, K.; Rooses, A.; Frizon, F.

    2013-11-01

    Effects of gamma irradiation on metakaolin based Na-geopolymer have been investigated by external irradiation. The experiments were carried out in a gamma irradiator with 60Co sources up to 1000 kGy. Various Na-geopolymer with three H2O/Na2O ratios have been studied in terms of hydrogen radiolytic yield. The results show that hydrogen production increases linearly with water content. Gamma irradiation effects on Na-geopolymer microstructure have been investigated with porosity measurements and X-ray pair distribution function analysis. A change of pore size distribution and a structural relaxation have been found after gamma ray irradiation.

  12. Influence of gamma ray irradiation on metakaolin based sodium geopolymer

    International Nuclear Information System (INIS)

    Effects of gamma irradiation on metakaolin based Na-geopolymer have been investigated by external irradiation. The experiments were carried out in a gamma irradiator with 60Co sources up to 1000 kGy. Various Na-geopolymer with three H2O/Na2O ratios have been studied in terms of hydrogen radiolytic yield. The results show that hydrogen production increases linearly with water content. Gamma irradiation effects on Na-geopolymer microstructure have been investigated with porosity measurements and X-ray pair distribution function analysis. A change of pore size distribution and a structural relaxation have been found after gamma ray irradiation

  13. Synthesis of Au Nanorods by Using Gamma-ray Irradiation

    Science.gov (United States)

    Okamoto, Akihiko; Nagata, Koichiro; Taguchi, Noboru; Iwase, Akihiro; Hori, Fuminobu

    2012-11-01

    To synthesize Au nanorods without the use of seed crystals, we applied gamma-ray irradiation from 60Co radioactive source to reduce aqueous solution containing Au ions. The total dose was fixed to 6.0 kGy with various dose rates from 0.4 to 13.6 kGy/h. After the irradiation, two surface plasmon bands in the range around 530 nm and above 700 nm were observed in UV/vis spectra. We observed by a transmission electron microscopy (TEM) that rod-shaped Au nanoparticles with the length of 20-25 nm, and the width of about 7-15 nm were produced as well as a small amount of spherical particles. The size and the aspect ratio of the Au nanorods are well correlated with gamma-ray irradiation dose rate; with increasing the dose rate, their size decreases and the aspect ratio increases.

  14. Dosimetry for high dose rate gamma ray irradiation equipment

    International Nuclear Information System (INIS)

    The dose rate and distribution of the machine gamma ray in the title were studied at the opportunity of its move to Gamma-ray Facilities using a glass dosimeter calibrated. The machine, Gammator M M38-3 (Radiation Machinery Corp.), W 24 in. x D 24 in. x H 63 in., had a source of 88.8 TBq 137Cs to irradiate samples of 60Co gamma source. For measuring the dose rate and distribution, glass dosimeters were fixed on an acryl plate stand of 3 in. x 8 in. by arranging in 3 rows (x axis) x 7 columns (y axis), and the stand was irradiated by gamma ray for 1 min. Irradiation was performed with either rotating or resting condition of the sample turntable and each exposure dose was read out. From the dosimeters at the center of rotation, water absorbed dose D =8.465 Gy was obtained (Mar. 30, 2010). The dose distribution along y axis was found to have 2 peaks of 1.18 and 1.08 times higher than the center above. Fluctuation was high at measurement on the resting turntable. As above, the distribution was not homogeneous depending on the feature of the sample, and turntable should be rotated during irradiation. The machine was operable from April, 2010. (T.T.)

  15. Apoptosis and necrosis in testes irradiated with gamma rays

    International Nuclear Information System (INIS)

    The present study focused on sub-microscopical investigation of apoptotic and necrotic cells in the testes of dogs subjected to single local irradiation with gamma rays at three different doses, 1.5 Gy, 3 Gy and 4 Gy, on days 1, 15, 30, 45, 120 and 150 after irradiation. On day 1 after irradiation, no necrotic cells were observed in the testicular tissue. The first cells in which apoptosis was observed on days 15 and 30 after irradiation with the lower dose were spermatogonia, spermatocytes and round spermatids. These cells showed morphological changes typical of apoptosis. Their depletion was observed on day 45 after irradiation and they were found in the lumen of seminiferous tubuli. Some dead cells were eliminated from seminiferous tubuli by phagocytosis by means of Sertoli cells. After irradiation with higher doses of gamma rays some cells of seminiferous epithelium showed morphological signs of apoptosis while other manifested necrosis. Sertoli cells and Leydig cells were considerably resistant to radiation. However, after irradiation with the highest dose of 4 Gy sporadic cells showed signs of apoptosis. On day 120 after irradiation the testes contained no necrotic cells and by day 150 spermiogenesis was recovered. (authors)

  16. Gamma-ray irradiation head for panoramic irradiation, and gamma-ray generator comprising such an irradiation head

    International Nuclear Information System (INIS)

    This invention concerns a panoramic irradiation irradiation-head, the rays emitted covering a solid angle. For this the target used is axisymmetrical about the axis of the accelerated beam and accelerated electron deflectors are provided so that these electrons strike the axisymmetrical target. The emission of high energy gamma rays by means of a linear accelerator is obtained in the following manner: electrons are furnished by a thermo-emissive cathode at a field of 30 to 50 kV for example. These electrons are then accelerated in a UHF (a few thousand MHz) accelerator section by high powered pulses (a few megawatts) of several microseconds and strike the target which is generally a tungsten pellet. When an electron hits the target, sudden braking occurs and electromagnetic radiation is emitted. Furthermore, electrons of the beam bring about the ionization of certain atoms of the target and the migrations of the electrons on the various coats of the atoms bring about the emission of photons. The intensity of the radiation depends on the cathode heating voltage and the directivity of the radiation emitted depends on the energy of the gamma rays emitted

  17. Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation

    CERN Document Server

    Koike, K; Koike, C; Okada, M; Chihara, H

    2002-01-01

    Interstellar matter is known to be strongly irradiated by radiation and several types of cosmic ray particles. Simulated interstellar matter, such as forsterite $\\rm Mg_{2}SiO_{4}$, enstatite $\\rm MgSiO_{3}$ and magnesite $\\rm MgCO_{3}$ has been irradiated with the $\\rm ^{60}Co$ gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of Kyoto University Reactor (KUR-LTL. Maximum fast neutron dose is $10^{17}n_f{\\rm /cm^{2}}$). After irradiation, samples are stored in liquid nitrogen for several months to allow the decay of induced radioactivity. We measured the luminescence spectra of the gamma ray irradiated samples during warming to 370K using a spectrophotometer. For the forsterite and magnesite, the spectra exhibit a rather intense peak at about 645 -- 655 nm and 660 nm respectively, whereas luminescence scarcely appeared in olivine sample. The spectra of forsterite is very similar to the ERE of the Red Rectangle.

  18. Synergistic effects of neutron and gamma ray irradiation of a commercial CHMOS microcontroller

    International Nuclear Information System (INIS)

    This paper presents the experimental results of a combined irradiation environment of neutron and gamma rays on 80C196KC20, which is a 16-bit high performance member of the MCS96 microcontroller family. The electrical and functional tests were made in three irradiation environments: neutron, gamma rays, combined irradiation of neutron and gamma rays. The experimental results show that the neutron irradiation can affect the total ionizing dose behaviour. Compared with the single radiation environment, the microcontroller exhibits considerably more severe degradation in neutron and gamma ray synergistic irradiation. This phenomenon may cause a significant hardness assurance problem. (condensed matter: structure, thermal and mechanical properties)

  19. Electrons versus gamma rays. Alternative sources for irradiation processes

    International Nuclear Information System (INIS)

    Energetic electrons and gamma rays are used for a variety of commercial irradiation processes such as the modification of polymeric materials, the sterilization of medical devices, the preservation of foods and the treatment of municipal and industrial wastes. The chemical and biological effects of these radiations are similar, but the differences in their physical characteristics and economics may favour one over the other for a particular application. Electron accelerators with energies under 5 MeV producing intense, high-power beams are mainly used for curing coatings and thin plastic and rubber products, while gamma-ray sources emitting diffuse radiation with substantially greater penetration are used predominantly for medical products and some agricultural commodities. The increasing demand for large gamma-ray sources and the currently limited supplies are now stimulating the development of electron accelerators of 5 to 15 MeV with more penetration that can provide an alternative to gamma sources for the treatment of packages and bulk materials. High-power bremsstrahlung (X-ray) generators can also be considered for applications requiring still greater penetration. Where either electrons or photons can provide satisfactory dose distributions within the products, the productivity of accelerators and gamma sources can be compared on the basis of available power and utilization efficiency. For example, a 10 MeV, 20 kW machine would be equivalent to 2 MCi of 60Co, assuming 50% and 35% power utilization, respectively. The price of such an accelerator might be comparable to that of a 60Co source, while at twice this power level, the accelerator would be substantially less expensive than 60Co. Operating and maintenance costs for a 40 kW machine would also be less than the cost of gamma source replenishment in a 4 MCi facility. High-power accelerators are also justifiable for smaller facilities since their higher capital cost can be compensated for by a reduction in operating cost due to a shorter work schedule. (author)

  20. A commercial gamma-ray irradiation plant in Japan

    International Nuclear Information System (INIS)

    In 1973, a commercial gamma-ray irradiation plant was constructed in Takasaki, about 100 km north of Tokyo. The plant has been used for both production of irradiated commercial products and irradiation services. The irradiation services are being made available for sterilization of both medical appliances such as disposable medical syringes, catheters, surgical sutures, and sterilization of feed stuffs for animals. Treatment of plastic materials and colouring of both crystals and glass wares are also undertaken. This facility can accommodate 600 kCi of 60Co and has a monthly treating capacity of 12,000 packages ( a standard carton of 340 mm x 400 mm x 500 mm) at an irradiation dose of 1 Mrad/hr. A receiving port for packages is on the second floor and the outlet of the irradiated packages on the first floor, with three lines of connecting loop conveyors between them, and the irradiation compartment in the center section. The space arrangement of the facility is well designed and gravity can be utilized for the transportation of the packages. Polymer impregnated coral is put on the market for ornamental building material on an order contract basis. (author)

  1. Gamma-ray spectroscopy on irradiated MTR fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Terremoto, L.A.A. E-mail: laaterre@net.ipen.br; Zeituni, C.A.; Perrotta, J.A.; Silva, J.E.R. da

    2000-08-11

    The availability of burnup data is an important requirement in any systematic approach to the enhancement of safety, economics and performance of a nuclear research reactor. This work presents the theory and experimental techniques applied to determine, by means of nondestructive gamma-ray spectroscopy, the burnup of Material Testing Reactor (MTR) fuel elements irradiated in the IEA-R1 research reactor. Burnup measurements, based on analysis of spectra that result from collimation and detection of gamma-rays emitted in the decay of radioactive fission products, were performed at the reactor pool area. The measuring system consists of a high-purity germanium (HPGe) detector together with suitable fast electronics and an on-line microcomputer data acquisition module. In order to achieve absolute burnup values, the detection set (collimator tube+HPGe detector) was previously calibrated in efficiency. The obtained burnup values are compared with ones provided by reactor physics calculations, for three kinds of MTR fuel elements with different cooling times, initial enrichment grades and total number of fuel plates. Both values show good agreement within the experimental error limits.

  2. Gamma-ray spectroscopy on irradiated MTR fuel elements

    Science.gov (United States)

    Terremoto, L. A. A.; Zeituni, C. A.; Perrotta, J. A.; da Silva, J. E. R.

    2000-08-01

    The availability of burnup data is an important requirement in any systematic approach to the enhancement of safety, economics and performance of a nuclear research reactor. This work presents the theory and experimental techniques applied to determine, by means of nondestructive gamma-ray spectroscopy, the burnup of Material Testing Reactor (MTR) fuel elements irradiated in the IEA-R1 research reactor. Burnup measurements, based on analysis of spectra that result from collimation and detection of gamma-rays emitted in the decay of radioactive fission products, were performed at the reactor pool area. The measuring system consists of a high-purity germanium (HPGe) detector together with suitable fast electronics and an on-line microcomputer data acquisition module. In order to achieve absolute burnup values, the detection set (collimator tube+HPGe detector) was previously calibrated in efficiency. The obtained burnup values are compared with ones provided by reactor physics calculations, for three kinds of MTR fuel elements with different cooling times, initial enrichment grades and total number of fuel plates. Both values show good agreement within the experimental error limits.

  3. Gamma-ray spectroscopy on irradiated MTR fuel elements

    International Nuclear Information System (INIS)

    The availability of burnup data is an important requirement in any systematic approach to the enhancement of safety, economics and performance of a nuclear research reactor. This work presents the theory and experimental techniques applied to determine, by means of nondestructive gamma-ray spectroscopy, the burnup of Material Testing Reactor (MTR) fuel elements irradiated in the IEA-R1 research reactor. Burnup measurements, based on analysis of spectra that result from collimation and detection of gamma-rays emitted in the decay of radioactive fission products, were performed at the reactor pool area. The measuring system consists of a high-purity germanium (HPGe) detector together with suitable fast electronics and an on-line microcomputer data acquisition module. In order to achieve absolute burnup values, the detection set (collimator tube+HPGe detector) was previously calibrated in efficiency. The obtained burnup values are compared with ones provided by reactor physics calculations, for three kinds of MTR fuel elements with different cooling times, initial enrichment grades and total number of fuel plates. Both values show good agreement within the experimental error limits

  4. Bacteriostatic activity of various antibiotics after gamma-ray irradiation

    International Nuclear Information System (INIS)

    The purpose of the work described was to discover whether the antibiotics used in medicine can be sterilized by gamma rays; in this preliminary study, only the antimicrobic activity - the principal criterion for this type of medicament - was evaluated. Thirty-three products belonging to the various families of antibacterial and antifungic antibiotics were studied. The substances were irradiated in the dry state and in an aqueous solution, using a caesium-137 irradiator. The antibacterial and antifungic activity before and after irradiation was investigated by the method of diffusion in gelose. When irradiated in the dry state, 14 antibiotics preserve normal activity up to a dose of 10 Mrad; at doses between 5 and 10 Mrad, 15 other antibiotics are subject to a variable, but moderate, loss activity; and four register a slight loss of activity at a dose of 2.5 Mrad. In an aqueous solution all but two of the antibiotics suffer total loss of activity at a dose of 2.5 Mrad. As most commercial antibiotics are supplied in the dry state, gamma irradiation may be a useful sterilization process. However, preparations such as eye lotions, suspensions, ointments, etc. should be excepted

  5. Gamma-ray Irradiation Induces Useful Morphological Variation in Bermudagrass

    Directory of Open Access Journals (Sweden)

    Songul SEVER MUTLU

    2015-12-01

    Full Text Available Bermudagrass, Cynodon dactylon (L. Pers. is a widely used warm-season turfgrass species in warmer regions of the world. Gamma (ɣ irradiation has been used to generate useful variations in turfgrass breeding for various morphological traits. The objective of the present study was to measure and determine variations in morphology and turfgrass characteristics of a native drought resistant bermudagrass germplasm irradiated with 70, 90 or 110 Gy using a 60Co source. The stolons containing a single node were irradiated and immediately planted for regeneration in a greenhouse at the Akdeniz University, Antalya, Turkey. Selected mutants regenerated from the irradiated stolons were clonally propagated and transplanted into plastic pots for further observations of turfgrass characteristics.  Survival rates of stolons exposed to 70, 90 and 110 Gy were 76%, 43% and 17% respectively, 6 weeks after treatment. Dosages of 85 and 57 Gy were determined as LD50 and LD20 for the cuttings, respectively. The linear reduction of survival rate with increasing gamma-rays was highly correlated (r2=0.99. A total of four mutant lines (0.3 % of the irradiated plants showed a distinct dwarfed growth habit. Three of these lines were originated from 70 Gy and one from 110 Gy. These mutant lines exhibited more dwarf growth habit, higher shoot density, finer leaf texture than parental genotype. Mutant lines developed in this study can be used for the development of improved bermudagrass cultivars for landscaping and sports turf.

  6. Induced parthenocarpy with pollen irradiated with gamma rays

    International Nuclear Information System (INIS)

    The results of serial experiments carried out during 1971-1974 using different vegetable crops for the purpose of obtaining parthenocarpous fruits with pollen irradiated with gamma rays are summed. Different varieties of tomatoes, cucumbers and sugar melons are used. The pollen was irradiated on the day on which it was collected with 1 to 500 kR (1500-1000 R/min) with immediate pollination of the respective flowers. The pollination of the flower was conducted with or without castration and with or without isolation depending on the varieties and the conditions of cultivating the plants. The fruits thus obtained were normal in size and shape and contained degenerated seed (flakes) witout cavities. Degustations in all cases established a fuller and richer taste in comparison with the control fruits. Biochemical indices for the same tomatoes varieties (sugars, vitamin C, acidity, dry substance determined refractometrically) show that the quality of the experimental fruits is better than the control ones. (A.B.)

  7. Effects of Combined Irradiation of Neutrons and {gamma}-Rays on the Pink Mutation Frequencies in Tradescantia

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Lee, Young Keun; Kim, Jae Sung [KAERI, Daejeon (Korea, Republic of); Shin, Hae Shick [Chungnam National Univ., Daejeon (Korea, Republic of); Hyun, Soung Hee [Eulji Univ., Daejeon (Korea, Republic of)

    2000-06-15

    The effects of combined irradiation of neutrons and {gamma}-rays were analysed by means of Tradescantia Stamen Hair (TSH) assay. Potted plants were irradiated with 0{approx}2 Gy of {gamma}-rays. For the combined treatments, the plants were irradiated with neutrons from {sup 252}Cf 24 hours before or after {gamma}-irradiation. The slopes of dose-response curves were 5.98, 6.17 and 7.48, in {gamma}-rays, {gamma}-rays+neutrons, and neutrons+{gamma}-rays irradiated groups, respectively. The biological efficacy of radiations in the induction of pink mutations increased by 25% in neutrons+{gamma}-rays irradiated group, while it increased by 12% in {gamma}-rays+neutrons irradiated group. The combined irradiation with two kinds of radiations results in the different efficacy of radiation depending on the order of irradiations, which is of great importance in the related fields such as sterilization and radiotherapy.

  8. Computer-controlled gamma-ray scanner for irradiated reactor fuel

    International Nuclear Information System (INIS)

    Gamma-ray scanning of irradiated fuel is an important nondestructive technique used in the thermal fuels behavior program currently under way at the Idaho National Engineering Laboratory. This paper is concerned with the computer-controlled isotopic gamma-ray-scanning system developed for postirradiation examination of fuel and includes a brief discussion of some scan results obtained from fuel rods irradiated in the Power-Burst Facility to illustrate gamma-ray spectrometry for this application. Both burnup profiles and information concerning fission-product migration in irradiated fuel are routinely obtained with the computer-controlled system

  9. Effect of gamma-ray irradiation on starch in sweet popato roots

    International Nuclear Information System (INIS)

    Starch contents, as well as the size and molecular weight, in sweet potato roots decreased during steerage at 30 degrees C after gamma-ray irradiation, accompanying the increase of sucrose content. No change in the starch and sucrose contents was observed in unirradiated specimens. By microscopy damaged starch granules were observed only in gamma-ray irradiated root. The results suggested that starch was converted into sucrose unirradiated sweet potato roots by the enzymes responsible for starch-sugar interconversion of which the activities were enhanced by gamma-ray irradiation

  10. Assays of residual antibiotics after treatment of {gamma}-ray and UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji Hye; Nam, Ji Hyun; Lee, Dong Hun [Chungbuk National University, Cheongju (Korea, Republic of); Yu, Seung Ho; Lee, Myun Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-03-15

    The pollution of antibiotics is a major cause of spreading antibiotics resistant bacteria in the environment. Applications of ozonation, UV, and {gamma}-ray irradiations have been introduced to remove antibiotics in the effluents from wastewater treatment system. In this study, we compared the chemical (HPLC) and biological (antimicrobial susceptibility test, AMS) assays in measuring of the concentrations of residual antibiotics after {gamma}-ray and UV irradiation. Most samples were degraded by {gamma}-ray irradiation (1 {approx} 2 kGy). However, lincomycin and tetracycline were not degraded by UV irradiation. The concentration of residual antibiotics, that was treated with {gamma}-ray and UV irradiation, measuring by bioassay was similar to HPLC. The concentrations of {gamma}-ray irradiated cephradine measured by AMS test were 2 times higher than of HPLC assay, indicating AMS test is more sensitive than HPLC assay. These results indicate that {gamma}-ray irradiation technique is more useful than UV irradiation, and biological assay is more useful to detect the antibiotics and toxic intermediates in antibiotics degradation.

  11. Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

    International Nuclear Information System (INIS)

    Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author)

  12. Gamma-ray irradiation tests of CMOS sensors used in imaging techniques

    OpenAIRE

    Cappello Salvatore G.; Pace Calogero; Parlato Aldo; Rizzo Salvatore; Tomarchio Elio

    2014-01-01

    Technologically-enhanced electronic image sensors are used in various fields as diagnostic techniques in medicine or space applications. In the latter case the devices can be exposed to intense radiation fluxes over time which may impair the functioning of the same equipment. In this paper we report the results of gamma-ray irradiation tests on CMOS image sensors simulating the space radiation over a long time period. Gamma-ray irradiation tests were carrie...

  13. Application of nondestructive gamma-ray and neutron techniques for the safeguarding of irradiated fuel materials

    International Nuclear Information System (INIS)

    Nondestructive gamma-ray and neutron techniques were used to characterize the irradiation exposures of irradiated fuel assemblies. Techniques for the rapid measurement of the axial-activity profiles of fuel assemblies have been developed using ion chambers and Be(?,n) detectors. Detailed measurements using high-resolution gamma-ray spectrometry and passive neutron techniques were correlated with operator-declared values of cooling times and burnup

  14. Effect of gamma ray irradiation on the ferroelectric and piezoelectric properties of barium stannate titanate ceramics

    International Nuclear Information System (INIS)

    Tin doped barium titanate ceramics has been obtained by solid state reaction method followed by high energy ball milling. The effect of heavy dose gamma ray irradiation on the ferroelectric and piezoelectric properties of the synthesized barium stannate titanate ceramics has been observed. It has been found that on irradiation the ferroelectric property decreases with decreasing values of Pr and Ec. The piezoelectric properties including d33, electrostrictive strain and electromechanical coupling coefficient (Kp) also decrease following the same trend of Pr and Ec. Grain size decreases and grain patterns become irregular after irradiation as observed from SEM micrographs. The Thermoluminescence (TL) property of the barium stannate titanate ceramics has also been investigated and reported. - Highlights: Gamma ray irradiation effects have been reported. The ferroelectric property decreases due to gamma ray irradiation. Values of different piezoelectric constants decrease upon irradiation. TL glow curve shows thermoluminescence property of the ceramic system

  15. Gamma ray irradiated AgFeO2 nanoparticles with enhanced gas sensor properties

    International Nuclear Information System (INIS)

    AgFeO2 nanoparticles were synthesized via a facile hydrothermal method and irradiated by various doses of gamma ray. The products were characterized with X-ray powder diffraction, UVvis absorption spectrum and transmission electron microscope. The results revealed that the crystal structure, morphology and size of the samples remained unchanged after irradiation, while the intensity of UVVis spectra increased with irradiation dose increasing. In addition, gamma ray irradiation improved the performance of gas sensor based on the AgFeO2 nanoparticles including the optimum operating temperature and sensitivity, which might be ascribed to the generation of defects. - Graphical abstract: Gamma ray irradiation improved the performance of gas sensor based on the AgFeO2 nanoparticles including sensitivity and optimum operating temperature, which might be ascribed to the generation of defects. - Highlights: AgFeO2 nanoparticles were synthesized and irradiated with gamma ray. AgFeO2 nanoparticles were employed to fabricate gas sensors to detect ethanol. Gamma ray irradiation improved the sensitivity and optimum operating temperature

  16. Comparative effectiveness of gamma-rays and electron beams in food irradiation

    International Nuclear Information System (INIS)

    Ionizing radiations which can be used for the treatment of foods are gamma-rays from Co-60 and Cs-137, accelerated electrons from a machine at an energy of 10 MeV or lower and X-rays from a machine at an energy of 5 MeV or lower. The Joint FAO/IAEA/WHO Expert Committee on the Wholesomeness of Irradiated Food held in 1980 concluded that the foods irradiated at overall average doses up to 10 kGy with the radiation listed above are wholesome for human consumption. While most of the commercial food irradiations are conducted with gamma-rays from Co-60, accelerated electrons are increasingly utilized for treating foods. An important difference between gamma-rays and accelerated electrons is the penetration capacity in materials. The penetration capacity of gamma-rays is much higher than that of accelerated electrons. Another important difference is the dose rate. The dose rates of gamma-rays from commercial Co-60 sources are 1-100 Gy/min, while those of electron beams from electron accelerators are 103-106 Gy/s. Ideally a comparison of the effect of different types of ionizing radiation should be carried out at the same dose rate but this has been difficult due to the design of irradiators. It is very difficult to draw a definite conclusion on the difference in the effectiveness in food irradiation between gamma-rays and electron beams based on published data. This chapter deals with as many reports as possible on the comparative effectiveness of gamma-rays and electron beams and on the effect of dose rate on chemical reactions and living organisms, whether or not they demonstrate any dependency of the effect of irradiation on dose rate and type of radiation. (author)

  17. Morphological Changes of Polystyrene Sorbents after Gamma-Rays Irradiation.

    Czech Academy of Sciences Publication Activity Database

    Aleksieva, Krasimira; Sasso, A.; Je?bek, Karel

    Praha : ?esk spole?nost chemickho inenrstv, 2009 - (Halfar, R.), s. 234 ISBN 978-80-86059-51-8. [Konference chemickho a procesnho inenrstv CHISA 2009 /56./. Srn, umava (CZ), 19.10.2009-22.10.2009] Institutional research plan: CEZ:AV0Z40720504 Keywords : gamma-rays * porosity * crosslinking Subject RIV: CI - Industrial Chemistry, Chemical Engineering www.chisa.cz/2009

  18. Studies on the influences of. gamma. -ray irradiation upon food additives, (6). Radiolysis of monosodium glutamate due to. gamma. -ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, M. (Shimonoseki Univ. of Fisheries, Yamaguchi (Japan)); Gohya, Y.; Ishio, S.

    1981-08-01

    The effect of ..gamma..-ray irradiation on monosodium glutamate (MSG) in aqueous solution and in ''kamaboko'' was investigated to evaluate the rate of decomposition of MSG and to elucidate the safety of the decomposed products, under the concentration of 106.9 mmol/l aqueous solution and 1% content of MSG in ''kamaboko''. In aqueous solution, MSG was decomposed by ..gamma..-ray irradiation, and G value was estimated to be 1.24. The decomposition of MSG resulted from deamination reaction was estimated to be 40% of the total decomposition. Glutamic acid content decreased as the dose of ..gamma..-ray increased in MSG-enriched ''kamaboko'', while it increased as the dose of ..gamma..-ray increased in MSG-free ''kamaboko''. Glutamic acid was liberated from the protein in ''kamaboko'', therefore the apparent decomposition rate of MSG in ''kamaboko'' was regarded as lower than actual.

  19. The effect of gamma ray irradiation on PAN-based intermediate modulus carbon fibers

    International Nuclear Information System (INIS)

    Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were conducted on PAN-based intermediate modulus carbon fibers to investigate the structure and surface hydrophilicity of the carbon fibers before and after gamma irradiation. Two methods were used to determine Youngs modulus of the carbon fibers. The results show that gamma ray irradiation improved the degree of graphitization and introduced compressive stress into carbon fiber surface. Gamma ray also improved the carbon fiber surface hydrophilicity through increasing the value of O/C and enhancing the quantity of oxygen functional groups on carbon fibers. No distinct morphology change was observed after gamma ray irradiation. The Youngs modulus of the fibers increased with increasing irradiation dose

  20. Simulation and Characterization of Gamma Ray Production by Petawatt Lasers Irradiating High-Z Solid Targets

    Science.gov (United States)

    Henderson, Alexander; Liang, Edison; Yepes, Pablo; Chaguine, Petr; Riley, Nathan; Dyer, Gillis; Pennington, Scott

    2012-10-01

    On interaction with a solid target an ultra-intense short pulse high-energy laser, such as the Texas Petawatt Laser (TPW), accelerates a sub-pico-second burst of electrons into the target at high energies. These electrons then undergo bremsstrahlung, producing a beam of high-energy gamma rays. Even for mm thick gold targets, most of the bremsstrahling gamma rays escape, while many hot electrons do not. Here we attempt to characterize the angular distribution, energy spectrum and total yield of these gamma rays as produced by the TPW irradiating mm thick gold targets. GEANT4 Monte-Carlo simulation results are then fitted to the data and used to extrapolate the results beyond the limits of the measurements. We will also discuss potential applications of such intense gamma-ray beams.

  1. Effect of. gamma. -ray irradiation on colour and fluorescence of pearls

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Yasunori; Miyoshi, Tadaki.

    1988-02-01

    The colour of cultured pearls of P. fucata can be changed by ..gamma..-ray irradiation, which has been applied to pearl processing. The effect of ..gamma..-ray irradiation on the colour and fluorescence of pearls was investigated experimentally. The experimental results show that a colour change of pearls to bluish-grey is mainly responsible for a decrease in the reflection factor of the nuclei. Furthermore, a significant change in the fluorescence spectra has been observed for pearls and nuclei. These changes are considered to be caused by the degradation of conchiolin contained in the nacre. Fluorescence from pearls is not affected by the nuclei, but the colour of pearls is affected. Thus, the fluorescence method is suitable for investigating the effect of ..gamma..-ray irradiation on the nacre.

  2. The Cellular Differences between Acute and Chronic Neutron and Gamma-Ray Irradiation in Mice

    International Nuclear Information System (INIS)

    Data on the shortening of the life span in mice by radiation show that an acute dose of gamma-rays may be as much as four times as effective as an equal dose of the same radiation administered chronically. However, for neutrons, chronic and acute administrations are equally effective. An analysis of these effects shows that for gamma-rays a certain fraction of the radiation injury is reparable, and that the value of this fraction depends on the dose and the dose rate. With neutrons, none of the damage appears reparable. For acute irradiation, the RBE is about 2 for shortening of the life span, but for chronic, may be as high as 8. Chromosome aberrations have been scored in liver cells of mice when treated with both chronic and acute doses of both gamma-rays and thermal neutrons. In all cases the percentage of aberrent cells is proportional to the shortening of the life span produced by the treatment. Further, with neutrons, acute and chronic irradiation is equally effective in producing chromosome abberations. For gamma-rays, acute irradiation may produce as much as four times the chromosomal damage as does chronic irradiation. This shows that some chromosomes can heal themselves following small doses of gamma-rays, but there is no chromosome healing following any dose of neutrons. The RBE using chromosome aberrations as a criterion is the same as for life shortening. These results give a firm cellular basis for the known biological differences between gamma rays and neutrons, and in addition give strong support to the concept that natural and radiation-induced aging are caused by spontaneous and radiation-induced mutations, respectively, in the somatic cells of animals. (author)

  3. Mutation induction in Philippine bananas c.v. 'Lakatan' thru gamma ray irradiation

    International Nuclear Information System (INIS)

    Banana is the most important crop grown in the Philippines. Among the cultivars grown, 'Lakatan' is the most popular and commands a higher price in the local market. Despite high production, losses due to over ripening, bruising and short shelf life is one of the major constraints in a successful banana industry. The use of chemicals for delayed ripening however, remains an issue of concern due to economic and organic products advocacy. Thus, development and generation of new improved 'Lakatan' cultivar through gamma ray irradiation was carried out. Mutation was induced in 'Lakatan', a popular Philippine cultivar using gamma ray irradiation. Radio sensitivity was established at 50Gy. Morphological, cytological and molecular analysis done showed significant variations between the irradiated samples and the non-irradiated plants. In terms of morphological parameters, gamma ray irradiation affected leaf traits resulting to increased leaf width, leaf length, and number of leaves. Stem girth on the other hand was significantly reduced. Cytological observations showed that gamma irradiation increased the epidermal width, leaf thickness and size of stomates but reduced the number of stomates. For post harvest attributes, gamma irradiation prolonged the shelf life of banana fruits from 11 days to 14 days. Molecular analysis showed that some markers (RAPD and AFLP) were able to detect unique bands in samples irradiated with 50Gy while the SSR markers did not detect any band difference between the irradiated samples and the control. (author)

  4. Modifications in the Morphology of Poly(styrene-co-divinylbenzenes) Induced by Gamma-ray Irradiation.

    Czech Academy of Sciences Publication Activity Database

    Aleksieva, Krasimira; Sassi, A.; Je?bek, Karel

    2010-01-01

    Ro?. 70, ?. 6 (2010), s. 361-365. ISSN 1381-5148 Institutional research plan: CEZ:AV0Z40720504 Keywords : gamma-ray irradiation * specific surface area * polymer morphology Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.546, year: 2010

  5. Influence of irradiation of gamma-ray on the pulping and paper making, (2)

    International Nuclear Information System (INIS)

    In kraft pulping and neutral sulphite pulping of gamma-ray irradiated chips, the influence of irradiation on the defiberability of the yielded pulps were investigated. The results were summerized as follows: 1) In kraft pulping, the defiberability becomes inferior by the irradiation of 5 x 105R. 2) In neutral sulphite pulping, the defiberability seems to become somewhat better by the irradiation of 106R. And kapper number does not change within the area of the high pulp yield but it becomes smaller according to the decrease of the total pulping yield by the irradiation of 106R, in comparison with the case of no-irradiation. (author)

  6. Effect of gamma-ray irradiation on cord blood lymphocyte proliferation and NK cell activity

    International Nuclear Information System (INIS)

    Objective: To investigate the effects of gamma-ray irradiation on cord blood lymphocyte proliferation and NK cell activity. Methods: Freshly isolated mononuclear cells from human cord blood were irradiated with different doses (0.248-15.872 Gy) of gamma-rays. The lymphocyte proliferation and NK cell activity were measured using 3H-TdR incorporation assay and 3H-TdR release assay, respectively. Results: In dose range of 0.248-15.872 Gy, lymphocyte proliferation was inhibited and the inhibition rate was positively correlated with the irradiation dose(r=0.839, P<0.05). Lymphocyte proliferation was not found in dose range of 3.968-15.872 Gy. Irradiation doses from 0.248 to 1.984 Gy could enhance NK cell activity. The activity of NK cells was reserved after irradiated with 3.968 Gy. Within the dose range of 5.952-15.872 Gy, NK cell activity was significantly inhibited. Conclusion: Lymphocyte proliferation is inhibited and the activity of NK cell is reserved when irradiated with the dose of 3.968 Gy gamma-rays. So if the lymphocytes are irradiated with such a dose before donor lymphocytes infusion or mix-cord blood transplantation, the effect of graft versus host disease (GVHD) could be decreased whereas the effect of graft versus leukemia (GVL) reaction could be reserved simultaneously during adoptive cellular immunotherapy. (authors)

  7. Effects of gamma-ray irradiation on leaching of simulated 133Cs+ radionuclides from geopolymer wasteforms

    International Nuclear Information System (INIS)

    Highlights: • γ-ray irradiation caused more Cs+ leaching out from geopolymer wasteform. • Pore structure change induced by irradiation caused the increase of leachability. • Fly-ash-based geopolymer is a potential material for radionuclide immobilization. - Abstract: Leaching of simulated 133Cs+ radionuclides from geopolymer wasteforms was examined with regard to effects from gamma-ray irradiation. Specifically, the compressive strengths, microstructures, pore structures, and leaching resistance of geopolymer wasteforms before and after irradiation were characterized. The leaching experiments were performed by immersion of wasteforms in deionized water, ground water, and seawater. It was found that gamma rays did not produce significant morphological changes, except for changes in the pore size distribution. The cumulative leaching fraction of all the leachants from the irradiated samples increased relative to the non-radiated samples, particularly during long leaching periods (11–42 days). These results, and those from a mercury intrusion porosimeter analysis, can be attributed to irradiation-induced changes in pore structure. All the leaching indexes were greater than the minimum acceptable value of 6.0 set by the American Nuclear Society Standards committee, which indicated that the fly-ash geopolymers are suitable for radionuclide immobilization. However, the effects of gamma-ray irradiation on the immobilization of radionuclides cannot be ignored

  8. Studies of Gamma-Ray-Irradiated Human Immunoglobulin G

    International Nuclear Information System (INIS)

    Freeze-dried IgG with incomplete anti-Rh0(D) activity retained its reactivity after irradiation with a dose of 1.5 - 2.5 Mrad ?-rays. A portion of the irradiated protein was insoluble. Gel-filtration on Sephadex G-200 indicated the presence of aggregated IgG in addition to the non-aggregated form. Proteolytic experiments revealed an altered digestibility of the protein with papain after irradiation. (author)

  9. Effects of gamma-ray irradiation on cellulase secretion of Trichoderma reesei

    International Nuclear Information System (INIS)

    Trichoderma reesei was irradiated with gamma rays to investigate the effects of different dosages on cellulase production. Doses above 0.7 kGy induced cell lysis. Cell growth began to be obstructed at 2.0 kGy. As a result, the cells irradiated at 2.0 kGy secreted 1.8 times as much cellulase as the untreated cells

  10. Qualities of Patin Fishball Irradiated by Gamma Rays (60Co)

    International Nuclear Information System (INIS)

    An experiment on patin fishball quality using gamma irradiation (60Co) has been conducted. Samples were irradiated at 0, 1, 3 and 5 kGy and stored in refrigerator at temperature 10 oC for sixty days. Samples were analysed every fifteen days, except content of fat and protein that analysed only at the beginning and the end of storage. The purpose of this experiment is to know the quality changes of patin fishball irradiated during storage, by measuring of chemical (content of fat, protein, water, TVB value, pH value) and microbiology (TPC aerobic and anaerobic bacteria) changes. The results showed that irradiation did not affect macro nutrient contents (content of fat, protein and water) of patin fishball during storage but irradiation can affect TVB and pH values. Irradiation at 1 kGy can reduce one logarithmic cycle of total aerobic and anaerobic bacteria. The storage life of irradiated patin fishball treated at 1, 3 and 5 kGy could be extended up to 15, 30 and 60 days, respectively. Control samples the storage life could be extended less than 15 days. (author)

  11. Physico-chemical characterization of gamma rays irradiated crotamine

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Karina Corleto de; Spencer, Patrick Jack; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], e-mail: kcorleto@usp.br

    2009-07-01

    Ionizing radiation can change the molecular structure and affect the biological properties of biomolecules. It has been employed to attenuate animal toxins. Crotamine, a toxin from Crotalus durissus terrificus (Cdt), is a highly basic polypeptide (pI - 10.3), with myotoxic activity and molecular weight of 4882 Da. It is composed of 42 amino acids residues and reticulated by three disulfide bonds. This study aimed the characterization of irradiated crotamine using Circular Dichroism (CD), Fluorescence Spectroscopy and Differential Scanning Calorimetry (DSC) techniques. We used size exclusion and ion-exchange chromatography to purify it from Cdt crude venom. The pure crotamine was irradiated with 2.0 kGy from a {sup 60}Co source. Native and irradiated crotamine were analyzed in a fluorescence spectrophotometer (Hitachi F-4500), under excitation wavelength at 275 nm and the emission was scanned from 300 to 500 nm. The analysis of fluorescence quenching showed that the irradiated form displayed a lower quantum yield when compared to the native form. CD spectra, obtained from a Jasco, J-180 spectropolarimeter, of native and irradiated crotamine solutions, showed a discrete change between the samples, from apparently ordered conformation to a random coil. Finally, the thermodynamics analysis, realized in a calorimeter METTLER TOLEDO, DSC 822e, showed that irradiation promoted changes in the calorimetric profile. Our results indicate that irradiation leads to progressive changes in the structure of the toxin, which could explain the decrease in myotoxic activity. (author)

  12. Selection of variants with high levels of biotin from cultured green Lavandula vera cells irradiated with gamma rays

    International Nuclear Information System (INIS)

    Cultured green Lavandula vera cells were irradiated with various dosages of gamma rays which increased the variation in the amount of free biotin produced by the cell clones. Variant sublines containing much more free biotin than the original line were obtained by repeated selection. The effectiveness of gamma rays for the induction of the variant sublines is described

  13. Gamma-ray irradiation induced bulk photochromism in WO3-P2O5 glass

    Science.gov (United States)

    Shen, Wei; Baccaro, Stefania; Cemmi, Alessia; Xu, Xiaoqing; Chen, Guorong

    2015-11-01

    In the present work, photochromism of WO3-P2O5 glass under gamma-ray irradiation was reported. As-prepared glass samples with different WO3 content are all optically transparent in the visible wavelength range thanks to the addition of a small amount of oxidizing couple Sb2O3-NaNO3. The photochromic properties are identified by transmission spectra of the glasses before and after irradiation. The results show that the irradiation induced darkening results from the reduction of W6+ to W5+ or W4+. The existence of WO6 clusters in glasses of high WO3 content is proved by XPS, which is the main reason for the obvious photochromic effects. The WO3-P2O5 glass is a promising candidate in gamma-ray sensitive detector.

  14. Low temperature gamma-ray irradiation effects on polymer materials

    International Nuclear Information System (INIS)

    The gamma radiation induced degradation of glass fiber reinforced plastic (GFRP) and polymethylmethacrylate (PMMA) at 77K was examined by flexural test and gas analysis after irradiation and compared by the irradiation at room temperature. The decrease in flexural strength at break was much less at 77K than at RT. The evolution of CH4, CO and CO2 was also depressed at 77K. The temperature dependence of the degradation closely relates to the local molecular motion of matrix resin during irradiation. Polytetrafluoroethylene (PTFE) was also studied by irradiation at RT, 77K and 4K in terms of tensile elongation and molecular weight. The degradation was much less at 77K and 4K than at RT, and the same between 77K and 4K. (author)

  15. Gamma-ray irradiation tests of CMOS sensors used in imaging techniques

    Directory of Open Access Journals (Sweden)

    Cappello Salvatore G.

    2014-01-01

    Full Text Available Technologically-enhanced electronic image sensors are used in various fields as diagnostic techniques in medicine or space applications. In the latter case the devices can be exposed to intense radiation fluxes over time which may impair the functioning of the same equipment. In this paper we report the results of gamma-ray irradiation tests on CMOS image sensors simulating the space radiation over a long time period. Gamma-ray irradiation tests were carried out by means of IGS-3 gamma irradiation facility of Palermo University, based on 60Co sources with different activities. To reduce the dose rate and realize a narrow gamma-ray beam, a lead-collimation system was purposely built. It permits to have dose rate values less than 10 mGy/s and to irradiate CMOS Image Sensors during operation. The total ionizing dose to CMOS image sensors was monitored in-situ, during irradiation, up to 1000 Gy and images were acquired every 25 Gy. At the end of the tests, the sensors continued to operate despite a background noise and some pixels were completely saturated. These effects, however, involve isolated pixels and therefore, should not affect the image quality.

  16. Effects of gamma-ray irradiation on leaching of simulated 133Cs+ radionuclides from geopolymer wasteforms

    Science.gov (United States)

    Deng, Ning; An, Hao; Cui, Hao; Pan, Yang; Wang, Bing; Mao, Linqiang; Zhai, Jianping

    2015-04-01

    Leaching of simulated 133Cs+ radionuclides from geopolymer wasteforms was examined with regard to effects from gamma-ray irradiation. Specifically, the compressive strengths, microstructures, pore structures, and leaching resistance of geopolymer wasteforms before and after irradiation were characterized. The leaching experiments were performed by immersion of wasteforms in deionized water, ground water, and seawater. It was found that gamma rays did not produce significant morphological changes, except for changes in the pore size distribution. The cumulative leaching fraction of all the leachants from the irradiated samples increased relative to the non-radiated samples, particularly during long leaching periods (11-42 days). These results, and those from a mercury intrusion porosimeter analysis, can be attributed to irradiation-induced changes in pore structure. All the leaching indexes were greater than the minimum acceptable value of 6.0 set by the American Nuclear Society Standards committee, which indicated that the fly-ash geopolymers are suitable for radionuclide immobilization. However, the effects of gamma-ray irradiation on the immobilization of radionuclides cannot be ignored.

  17. Bio metrical studies on gonads of adult ceratitis capitata (wied) following irradiation with gamma rays

    International Nuclear Information System (INIS)

    Adults of ceratitis capitata (wied.) aged from 24 to 42 hours., were irradiated with 30 and 60 Gy gamma rays. At intervals of 1, 3, 6, 8, 10, 13, 15, 17 and 20 days after irradiation, anatomical and bio metrical studies were performed to detect the extent of gonads recovery. In males, reduction in the size of the tests was recorded from the first day after irradiation, reached its maximum on the fifteenth to seventeenth day, and increased again on the seventeenth and twenty days. No complete recovery of gonads could be expected in spite of this increase. In females, observed reduction in the size of the ovaries was recorded from the first till the fifteenth day after irradiation, followed by a slight increase on the seventeenth day and ended by another decrease on the twenty day. Also, reduction in the number of ovarioles as well as atrophied ovaries were observed. No recovery of female gonads was expected. In general females are sensitive to gamma rays than males and the dose of 30 Gy gamma rays is suitable for sterilizing 24 to 42 hours. old adults. The proper time for repeating the release of sterilizing adults for controlling programmes is every two weeks after irradiation. 2 fig

  18. Electrochemical and corrosion behavior of passive film on stainless steels after gamma-ray irradiation

    International Nuclear Information System (INIS)

    The nature and structure of passive film on AISI 304L and AISI 446 stainless steels, after bare metal anodic oxidation and after the subsequent galvanostatic reduction or gamma-ray irradiation of the oxide film formed, were investigated by XPS and Electrochemical Impedance Spectroscopy (EIS). Atomic Absorption Spectroscopic (AAS) analysis of irradiated solution was also undertaken. Results obtained from XPS measurement indicated that gamma-ray irradiation can have significant effects on the stability of passive film due to the release of iron and corresponding enrichment in chromium oxides. The EIS technique was used to elucidate the physical structure of passive film after irradiation and galvanostatic reduction. The passive film formed on AISI 304L and AISI 446 stainless steels have a compact structure. The galvanostatic treatment leads to a film composed of two layers, the external one showing a spongy-like structure, while the gamma-ray irradiation treatment leads to a thinner compact film exhibiting higher capacitive behavior compared to that of unirradiated samples

  19. Gamma-ray irradiation of a boreal forest ecosystem

    International Nuclear Information System (INIS)

    A long-term radiation ecology research project called Field Irradiator - Gamma (FIG) began at the Whiteshell Nuclear Research Establishment in 1968. The experimental area is in southeastern Manitoba and is located on the western edge of the Precambrian shield. The project studies the ecological effects continuous exposure to a gradient of gamma radiation has on a mixed boreal forest ecosystem. The gradient ranges from 1 to 460,000 times the natural background radiation level. This paper describes the forest, the gamma irradiator and its radiation field, and the research program

  20. Effect of Low Dose gamma-ray Irradiation on the Germination and Growth in Red Pepper (Capcicum annuum L.)

    International Nuclear Information System (INIS)

    This study was conducted to determine the effect of low dose gamma-ray irradiation in red pepper. The germination percentage, plant, the number of flower, chlorophyll contents, leaf length and width were observed from plants grown with red pepper seeds irradiated with various low dose of gamma-ray. The germination percentage of irradiation group treatmented gamma-ray was much higher than that of the control. Specially the germination percentage after sowing red pepper seeds on paper towel was higher than 1,000 and 2,000 rad irradiation group. The height of plants grown with red pepper seeds irradiated with gamma-ray was increased in 100, 200 and 400 rad irradiation group compared to that of the control. The height of plant from 2,400 rad irradiation group, however, was shorter than that of the control. Nutrient contents of leaves of plants grown with red pepper seeds irradiated with various dose of gamma-ray were significantly increased in 800 and 1,200 rad irradiation group. Electric conductivity (EC) of the water used for seed germination was lower irradiation group than control group. Therefore, there was the possibility to increase the germination and plant growth with gamma-ray of adequate low dose

  1. Glasses, Coatings, Glues and Gamma-ray Irradiation

    International Nuclear Information System (INIS)

    Most of the alignment systems for LHC experiments use optomechanical elements confirming a network of points that are monitored by laser beams. LHC experiments, working at the expected nominal luminosity, will induce an extremely high irradiation. basic components such as glasses, coatings and glues may change and their performance may degrade significantly. We have tested various components and identified some of them that can stand 10 years of LHC operation. (Author) 11 refs

  2. Glasses, Coatings, Glues and Gamma-ray Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Barcala, J.M.; Fernandez, M. G.; Ferrando, A.; Fuentes, J.; Josa, M. I.; Molinero, A.; Oller, J. C. [Ciemat. Madrid (Spain); Arce, P.; Calvo, E.; Figueroa, C. F.; Rodrigo, T.; Vila, I.; Virto, A. L. [Universidad de Cantabria. Santander (Spain); Beigveder, J. M.; Genova, I.; Perez, G.; Ruiz, J. A. [CIDA. Madrid (Spain)

    2001-07-01

    Most of the alignment systems for LHC experiments use optomechanical elements confirming a network of points that are monitored by laser beams. LHC experiments, working at the expected nominal luminosity, will induce an extremely high irradiation. basic components such as glasses, coatings and glues may change and their performance may degrade significantly. We have tested various components and identified some of them that can stand 10 years of LHC operation. (Author) 11 refs.

  3. Post irradiation changes of haematological parameters in mammals blood after high dose gamma rays

    International Nuclear Information System (INIS)

    In our experiment we monitored post irradiation changes of haematological parameters in rats after single total - body dose of gamma rays 15 Gy. Significant decrease was in the erythrocyte count at 6th day (P th day (P th day. In the white blood picture in all experimental groups was leukopenia (P < 0.001), which was characterized by neutrophilia (P < 0.001) and lymphopenia (P < 0.001). (authors)

  4. Study of uptake and endocytosis of gamma rays-irradiated crotoxin by mice peritoneal macrophages

    International Nuclear Information System (INIS)

    The purpose was to investigate the uptake and endocytosis of 2000 Gy 60Co irradiated crotoxin through mouse peritoneal macrophages, correlating with native one and another non related protein, the ovalbumin. Native (CTXN) or 2000 Gy 60 Co ?-rays (dose rate 540 Gy/hour) irradiated crotoxin (CTXI) or ovalbumin processed of same manner (OVAN - OVAI) were offered to mouse peritoneal macrophages and their uptake was evaluated by immunohistochemistry and quantitative in situ ELISA. The involvement of scavenger receptors (ScvR) was evaluated by using blockers drugs (Probuco-PBC or Dextran Sulfate - SD) or with nonspecific blocking using fetal calf serum (FBS). The morphology and viability of macrophages were preserved during the experiments. CTXI showed irradiation-induced aggregates and formation of oxidative changing were observed on this protein after gamma rays treatment. By immunohistochemistry we could observe heavy stained phagocytic vacuole on macrophages incubated with CTXI, as compared with CTXN. Quantitatively by in situ ELISA, the sema pattern was observed, displaying a 2-fold CTXI incorporation. In presence of PBC or SD we could find a significant decrease of CTXI uptake but not of CTXN. However the CTXN uptake was depressed by FBS, not observed with CTXI. OVA, after gamma rays treatment, underwent a high degradation suffering a potent incorporation and metabolism by macrophages, with a major uptake of OVAI in longer incubation (120 minutes). Gamma rays (60 Co) produced oxidative changes on CTX molecule, leading to a uptake by ScvR-mice peritoneal macrophages, suggesting that the relation antigen-presenting cells and gamma rays-modified proteins are responsible for the better immune response presented by irradiated antigens. (author)

  5. Shoot regeneration of callus culture from irradiated sheed of piper nigrum L by gamma rays

    International Nuclear Information System (INIS)

    Shoot regeneration was obtained from callus that induced by irradiated seed with 25 and 50 Gy of gamma-rays and then on M.S. medium containing NAA 1 ppm and 2-ip 0.5 ppm. Irradiated seed with a dose of 25 Gy produced normal root and failed to produce shoot, but rice callus. Irradiated seed with a dose of 50 Gy pruduce callus only. Shoot differentiation occured after the callus were cultured on M.S., medium containing 2-ip 1 ppm and Kinetin 2.5 ppm. (authors). 9 refs, 3 figs

  6. Protection of negative gravitaxis in Euglena gracilis Z against gamma-ray irradiation by Trolox C

    Energy Technology Data Exchange (ETDEWEB)

    Sakashita, Tetsuya; Doi, Masahiro; Yasuda, Hiroshi; Fuma, Shoichi [National Inst. of Radiological Sciences, Chiba (Japan). Research Center for Radiation Safety; Hader, D.P. [Biologie der Friedrich-Alexander Univ., Erlangen (Germany). Inst. fuer Botanik und Pharmazeutische Biologie

    2002-12-01

    The protective effects of Trolox on the inhibition of negative gravitaxis in Euglena gracilis exposed to 200 Gy {sup 60}Co gamma-rays were examined using different concentrations (1, 10 and 100 {mu}M). The orientation precision of the negative gravitaxis was quantified using the r-value. A significant decrease in the r-value was observed in gamma-irradiated samples (0.18+/-0.03) compared to those of non-irradiated samples (0.47+/-0.03). There were no significant changes in the r-value of cells exposed to 200 Gy gamma-rays by the addition of 1 or 10 {mu}M of Trolox. A significant increase (0.19) in the r-value of cells exposed to 200 Gy with 100 {mu}M Trolox was observed. The results indicates that Trolox at a concentration of 100 {mu}M protects negative gravitaxis against {sup 60}Co gamma-ray irradiation at a dose of 200 Gy. It also suggests that the negative gravitaxis of Euglena gracilis is affected by free radicals.(author)

  7. Protection of negative gravitaxis in Euglena gracilis Z against gamma-ray irradiation by Trolox C

    International Nuclear Information System (INIS)

    The protective effects of Trolox on the inhibition of negative gravitaxis in Euglena gracilis exposed to 200 Gy 60Co gamma-rays were examined using different concentrations (1, 10 and 100 ?M). The orientation precision of the negative gravitaxis was quantified using the r-value. A significant decrease in the r-value was observed in gamma-irradiated samples (0.18+/-0.03) compared to those of non-irradiated samples (0.47+/-0.03). There were no significant changes in the r-value of cells exposed to 200 Gy gamma-rays by the addition of 1 or 10 ?M of Trolox. A significant increase (0.19) in the r-value of cells exposed to 200 Gy with 100 ?M Trolox was observed. The results indicates that Trolox at a concentration of 100 ?M protects negative gravitaxis against 60Co gamma-ray irradiation at a dose of 200 Gy. It also suggests that the negative gravitaxis of Euglena gracilis is affected by free radicals.(author)

  8. Gamma ray spectra from targets irradiated by picosecond lasers

    Science.gov (United States)

    Seely, J. F.; Szabo, C. I.; Feldman, Uri; Chen, Hui; Hudson, L. T.; Henins, A.

    2011-09-01

    Photon spectra in the energy range 60 keV to 1 MeV were recorded from targets irradiated by the LLNL Titan and LLE EP picosecond lasers. The radiation consisted of K-shell radiation, bremsstrahlung radiation from MeV electrons, and preliminary evidence for 511 keV positron annihilation radiation. The spectra were recorded by two instruments, an energy-dispersive CCD detector with a CsI phosphor coating that operated in the single-hit per pixel mode and was absolutely calibrated using a Cs-137 662 keV source, and a wavelength-dispersive Cauchois type spectrometer employing a curved Ge(220) transmission crystal that operated in the first and second diffraction orders with high spectral resolution. The calibrated photon energy distributions from Au, Eu, and Al targets are compared to the energetic electron distributions emerging from the targets.

  9. Biophysical assessment of blood after whole body gamma rays irradiation

    International Nuclear Information System (INIS)

    this work studies the effect of whole body exposure to different doses of gamma radiation on some biophysical properties of blood. adult male rats weighing 200-250 gm were exposed to 1,2.5,3.5, 5,7 and 9 Gy single doses using Cs-137 source available at national center for radiation research and technology (NCRRT). blood samples were obtained from the left ventricle of the heart 24 hours after irradiation . the rheological properties of whole blood were measured immediately after dissection at 25 c using brookfield DV-lll cone plate rheometer and the following parameters were calculated: viscosity, yield stress, consistency, flow and aggregation indices. since erythrocytes constitute more than 95% of the particulate matter in blood, they govern the flow properties of blood

  10. Gamma-rays irradiation of greenwood cuttings cherry varieties

    International Nuclear Information System (INIS)

    Results are reported of irradiation of greenwood cuttings of the sweet cherry grafted varieties Napoleon, Drogans Gelbe and Ryzhdavishka Belvitsa, performed at 2500 R. The treated buds have been treated on rootstocks in a nursery and trees have been raised from the grafts in a planting. Different teratological alterations were observed in shoots of most trees developed from treated buds such as fasciations, bi-, tre-, and tetra-furcation as well as branchlets with a pseudodichotomical ramification. Several forms, having a very good fruit bearing and lower strength of growth than the initial varieties, were selected. A large number of slightly growing mutagenous forms were established of the Drogans Gelbe variety. Their fruits do not differ substantially from those of the initial varieties. (author)

  11. Dielectric properties of wood irradiated with gamma-rays

    International Nuclear Information System (INIS)

    Molecular structure changes in wood resulting from gamma irradiation are discussed from the result of measurements on dielectric properties, X-ray diffraction, infrared spectra and moisture regain. Up to about 3 x 106 rad no marked structure changes are detected. In the range 3 x 106 to 107 rad, the moisture-regain value decreases, but little change in the dielectric absorption is observed. In the range 107 to 108 rad, the moisture-regain value decreased, and this would suggest some alteration in the submicroscopic structure and the chemical structure from chain cleavage and carbonyl and carboxyl group formation. On the other hand, the dielectric absorption increases and this would indicate that the number of methylol group contributing to the reorientation increases in the crystalline region (increase of crystalline defects) as well as in the amorphous region contributing to water absorption. At dose levels greater than 108 rad, the moisture-regain value starts to rise again, whereas the dielectric absorption decreases rapidly. These would suggest that marked reduction of the crystalline region and oxidization of methylol group take place. Furthermore, the mechanism of an additional dielectric relaxation process occurred in low frequency range resulting from is discussed. (auth.)

  12. Gamma ray irradiation to roots of tea-plants and induced mutant system

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa (National Research Inst. of Vegetables, Ornamental Plants and Tea, Ano, Mie (Japan))

    1990-11-01

    In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.).

  13. Gamma ray irradiation to roots of tea-plants and induced mutant system

    International Nuclear Information System (INIS)

    In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.)

  14. Allogenic bone rods with freeze drying and gamma rays irradiation for treatment of fracture

    International Nuclear Information System (INIS)

    Opened reduction and internal fixation are the usual treatment of fracture, but both methods need a second operation for removal implants. The benefits of the bone rods are that they can avoid the removement of internal fixation and will be absorbed spontaneously. The bone rods are made of allogeneic compact bones with freeze-drying and gamma rays irradiation supplied by Shanxi Provincial Tissue Bank. The purpose of this study is to evaluate allograft reaction, the stability of the internal fixation, osteoinduction in the treatment of fracture using allogeneic bone rods with freeze drying and gamma rays irradiation. From May 1997 to May 1998, fourteen cases (male 12, female 2) of treatment were reviewed. The mean age was 37.3 (21-5 1). There were 3 medial malleolus fractures, 7 tibia and fibula fractures, 1 ulna and radius fracture, 1 lateral condyle of humerus fracture. The clinical results were satisfactory. Because the strength of the bone rods are weaker than that of screws, the bone rods are only indicated in the fixation of cancellous bones fracture and unloaded bone fracture. It can be used as a supplementary fixation of loaded bone. It is not indicated for fixation of comminuted fracture. More than two bone rods may be used in the fixation of fracture in order to get stability of the fracture and decrease stress between rods which will prevent the break of the bone rods. Allogeneic bone rods with freeze-drying and gamma rays irradiation can be used as implants of non-immunogenicity. There are no allograft reactions in all cases (including fever, leukocytosis, exudation or swelling in the wound). Although plenty of experimental studies have showed that freeze drying with gamma rays irradiation (below 50 KGy) would not destroy BMP of bone allograft, but there is no osteoinduction in our cases. The healing of a fracture and bridging external callus are similar as other operations. This new technique may have the following advantages compare with the screws: 1) there is no stress shielding, 2) no need for second operation for removing implants. Because there is no allograft reaction and lower price compared with other absorbable fixation material, we believe allogeneic bone rods with freeze drying and gamma rays irradiation are one of the excellent materials foic internal fixation

  15. Effect of cumulated dose on hydrogen emission from polyethylene irradiated under oxidative atmosphere using gamma rays and ion beams

    Science.gov (United States)

    Ferry, M.; Pellizzi, E.; Boughattas, I.; Fromentin, E.; Dauvois, V.; de Combarieu, G.; Coignet, P.; Cochin, F.; Ngono-Ravache, Y.; Balanzat, E.; Esnouf, S.

    2016-01-01

    This work reports the effect of very high doses, up to 10 MGy, on the H2 emission from high density polyethylene (HDPE) irradiated with gamma rays and ion beams, in the presence of oxygen. This was obtained through a two-step procedure. First, HDPE films were pre-aged, at different doses, using either gamma rays or ion beams. In the second step, the pre-aged samples were irradiated in closed glass ampoules for gas quantification, using the same beam type as for pre-ageing. The hydrogen emission rate decreases when dose increases for both gamma rays and ion beams. However, the decreasing rate appears higher under gamma rays than under ion beam irradiations and this is assigned to a lesser oxidation level under the latter. Herein, we show the effectiveness of the radiation-induced defects scavenging effect under oxidative atmosphere, under low and high excitation densities.

  16. Possibilities for creating high protein bean forms by irradiation with cesium 137 gamma-rays

    International Nuclear Information System (INIS)

    Six Columbia lines bean plants suitable for direct combine-harvesting are used to induced mutation variations. The seeds are irradiated presowing with gamma-rays (Cs-137) in two ways - only once with 120 Gy and six times 4 hours daily with 20 Gy. The applied irradiation resulted into increase variability in protein content of the seeds of M2 plants. Variations of diverse character are established, depending on the genotype varieties. Mutant forms of more than 29% protein content which are of interest to the plant breeding, are obtained. 12 refs., 3 tabs. (author)

  17. Deep hole traps created by gamma-ray irradiation of GaInP

    Energy Technology Data Exchange (ETDEWEB)

    Sung Wei-Jer; Liu Tong-Yuan; Yang Su-Lin; Huang Kai-Feng; Tseng Tseung-Yuen [National Chiao Tung Univ., Hsinchu, Taiwan (China); Chou, Fong-In; Wei, Yuan-Yaw [NSTDC of National Tsing Hua Univ., Hsinchu, Taiwan (China)

    2001-12-01

    Deep hole traps created by gamma-ray irradiation of Al/GaInP Schottky diodes grown by metal-organic chemical vapor deposition (MOCVD) were studied by using deep level transient spectroscopy (DLTS) technique. Two distinct deep hole traps, A and B, were observed in the irradiated GaInP samples. According to the analysis of trap concentration in various samples, the trap A is verified as a bulk defect located at 0.29 eV above the valance band. Meanwhile, the trap B is an interface state originated from the junctions of Al/Mg-doped GaInP contacts. (author)

  18. Deep hole traps created by gamma-ray irradiation of GaInP

    International Nuclear Information System (INIS)

    Deep hole traps created by gamma-ray irradiation of Al/GaInP Schottky diodes grown by metal-organic chemical vapor deposition (MOCVD) were studied by using deep level transient spectroscopy (DLTS) technique. Two distinct deep hole traps, A and B, were observed in the irradiated GaInP samples. According to the analysis of trap concentration in various samples, the trap A is verified as a bulk defect located at 0.29 eV above the valance band. Meanwhile, the trap B is an interface state originated from the junctions of Al/Mg-doped GaInP contacts. (author)

  19. Irradiation effect of transistor by Co-60 gamma rays and electron beams

    International Nuclear Information System (INIS)

    In order to evaluate radiation resistance of semiconductor devices which are used in radiation environments of artificial satellites and nuclear power plants, effects of radiation on the DC gain, leak current and switching time of typical transistor devices were investigated. Tested devices are PNP bi-polar transistor (2SB603), NPN bi-polar transistor (2SC764) and power MOS transistor (2SK458). Irradiation were carried out by Cobalt-60 gamma rays and electron beams of 1 and 2 MeV at exposure rates ranging from 102 to 106 R/h, and at temperature ranging from -40degC to 100degC. The following results were obtained. (1) 2SB603: Changes of the DC gain and leak current are larger in low exposure rate irradiations, and large exposure rate dependency is observed. The DC gain change is based on mainly increase of the base current. The exposure rate dependency is observed in the reverse saturation current and voltage, but in the switching time. (2) 2SC764: The exposure rate and temperature dependencies on irradiation effect are not clear, and the radiation resistance is over two orders higher than 2SB603 in the various properties. (3) 2SK458: The exposure rate and temperature dependencies on irradiation effect are small. (4) Irradiation effect on 2SB603 by electron beams is smaller than that by gamma-rays, and the exposure rate effect is observed. No difference between electron beams and gamma rays is observed for 2SC764 and 2SK458. (author)

  20. Effect of gamma-ray irradiation on the deoxygenation of salt-containing water using hydrazine

    International Nuclear Information System (INIS)

    In spent fuel pools at the Fukushima Daiichi nuclear power plant, hydrazine was added to salt-containing water in order to reduce dissolved oxygen. Hydrazine is known to reduce dissolved oxygen in high-temperature pure water, but its deoxygenation behavior in salt-containing water at ambient temperature in the presence of radiation is unknown. Deoxygenation using hydrazine in salt-containing water was thus investigated using a 60Co gamma-ray source and artificial seawater at room temperature. Water samples containing a small amount of hydrazine were irradiated at dose rates of 100 - 10,000 Gy/h. The concentration of dissolved oxygen in the water samples was measured before and after irradiation. Notably, a decrease in the dissolved oxygen was only observed after irradiation, and the dissolved oxygen concentration decreased with increasing dose rate and irradiation time. The rate of decrease in the amount of dissolved oxygen using hydrazine was slow in the presence of salts. Kinetic considerations suggested that the deoxygenation of the salt-containing water exposed to gamma-ray irradiation using hydrazine was suppressed by chloride ions. (author)

  1. Spatial charge in low density polyethylene irradiated with low dose gamma-ray

    International Nuclear Information System (INIS)

    The research on the effect that radiation exerts on polymer insulation materials is indispensable for the improvement of safety in nuclear power generation, future nuclear fusion power generation and the expansion of space utilization, and it is important also as the technique for examining the electrical properties of polymer insulation materials themselves. However, in the case of carrying out irradiation at relatively low dose, the example of the research on the initial state of deterioration is few. Therefore, in this study, through the measurements of thermal pulse current, residual voltage, thermal stimulation currents, radiation-induced electrical conduction and other experiment, the behavior of spatial charges in the low density polyethylene irradiated with low dose gamma-ray was investigated. Gamma ray was irradiated at room temperature in the atmosphere at the dose rate of 200 Gy/h. The samples and the experimental method and the results are reported. In the irradiated samples, at a relatively low electric field of 0.1 MV/cm, hetero spatial charges were formed near both electrodes. In the irradiation of 0.2 - 5 kGy, either many carriers are generated or the mobility of carriers increases, which is one of the causes of initial deterioration. (K.I.)

  2. Genetic variation of natural orchid phalaenopsis amabilis (L.) blume produce gamma ray irradiation

    International Nuclear Information System (INIS)

    New cultivars of Phalaenopsis amabilis (L.) Blume were obtained through gamma-rays Co-60 irradiation. The result showed phenotypic variation which justifies a molecular biology observation to investigate whether the variation was caused by the change on cultivar’s genotypic traits. A study to describe the genetic variability among individuals of the irradiated cultivars was then conducted using RAPD Technique. The materials used were cultivars obtained by 0, 15, 20, 25, 20+20 and 40 Gray irradiations. DNA genome of each plant was isolated and was amplified with 22 primers randomly. The PCR analysis was done with 1.5 % agarose. The DNA analysis used 8 selected primers out of 22. Polymorphism and molecular diversity were analyzed with Nei’s gene diversity method through GenAlex 6.1 program. The study showed that genetic diversity might be detected at the early growth stage of the gamma ray Co-60 irradiated cultivars using RAPD, and irradiation dose of 15 and 40 Gray gave high genetic diversity compared to control. (author)

  3. An aberration in gamma-ray enhanced reactivation of irradiated adenovirus in ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Ataxia telangiectasia (AT) is a rare human genetic disorder which includes a predisposition to lymphoreticular cancers and a hypersensitivity to conventional radiotherapy. Furthermore, AT cells in vitro exhibit a hypersensitivity to ionising radiation that appears to be correlated with an increased frequency of chromosomal aberrations, a resistance of de novo DNA synthesis to inhibition by radiation-induced DNA damage, a reduced mitotic delay and possible defects in DNA repair. A sensitive viral assay has been used to investigate the capacity of gamma-irradiated AT cells to support the replication of undamaged virus, as well as the extent to which the survival of radiation-damaged virus was affected by gamma-irradiation of these host cells prior to infection. The expression of such enhanced reactivation (ER) of both u.v.-irradiated and gamma-irradiated adenovirus type 2 (Ad2) was examined in a variety of normal and AT human fibroblast strains. For immediate infection of normal human fibroblasts, both a decrease in unirradiated virus expression and an increase in ER were observed with increasing gamma-ray dose to the cells. In contrast, AT fibroblasts were found to be deficient in gamma-ray ER of irradiated Ad2, and this defect appeared to be related to a marked relative radioresistance of unirradiated virus expression in AT compared to normal cells. (author)

  4. method of fabricating gamma ray irradiation source filled in a plastic tube

    International Nuclear Information System (INIS)

    Purpose: To fabricate gamma ray irradiation source with safety and effectively by filling target substances and spacers in a cylindrical covering material made of radiation resistant plastics and then mounting the tube into a radiation resistant irradiation capsule for radioactivation. Constitution: Each types of targets are previously filled together with fine wire spacers made of radiation resistant plastics in the covering material made of radiation resistant fine plastic tube, and the tube is filled within a radiation resistant plastic irradiation capsule. Then, by the irradiation of neutron rays, each of the targets can be activated. Various forms of targets can be used such as elemental metals, alloys and compounds depending on purposes of use and experiments. After the irradiation of the neutron rays, the polyethylene covering material and the nylon fine wire are not denatured by the radiation damages and the fabrication can be conducted with safety and effectively. (Seki, T.)

  5. Fractionated Irradiation of Mice with Fission Neutrons and Co60 Gamma Rays

    International Nuclear Information System (INIS)

    This paper deals with the comparative effects of fission neutrons and Co60 gamma-rays, delivered at low dose rates over a 13-week period, on survival in CF No. 1 female mice. Animals were exposed in the gamma-neutron chamber at Argonne's CP-5 research reactor. The dose rate was approximately 0.75 rad/min for the neutrons and 0.25 rad/min for the gamma-rays. Fractionation of the weekly neutron dose into one, three, or six doses did not appear to have a significant effect on the mean survival times of the irradiated mice. Thymic tumours were observed in at least 90% of the mice that died following these fractionated exposures to either neutrons or gamma-rays. The RBE (n/?) for these 13-week exposures at low dose rates appears to resemble the acute RBE (2.8) rather than the higher value (5 to 15) reported when mice are exposed for the length of their lives to small daily doses. (author)

  6. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    International Nuclear Information System (INIS)

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 1013 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

  7. Effect of gamma ray irradiation on deoxygenation by hydrazine in artificial seawater

    International Nuclear Information System (INIS)

    At the spent nuclear fuel pools in the Fukushima Daiichi Nuclear Power Plant, hydrazine has been added to reduce dissolved oxygen in the pool water containing salts. The reduction behavior of dissolved oxygen in seawater with hydrazine in the presence of radiation is unknown. The effect of gamma ray irradiation on deoxygenation by hydrazine in artificial seawater was investigated at room temperature. We placed the artificial seawater with a small amount of hydrazine under gamma ray irradiation at dose rates of 0.3-7.5 kGy/h. The concentration of dissolved oxygen in the solutions was measured before and after the irradiation. The concentration of dissolved oxygen hardly decreased in the absence of gamma radiation in a few hours, whereas it markedly decreased in the presence of gamma radiation. The concentration of dissolved oxygen decreased with irradiation time. At this moment, hydrazine concentration decreased more than twice the dissolved oxygen concentration. This shows that some gamma radiolysis products of hydrazine act as deoxidizers. The concentration of dissolved oxygen in artificial seawater could be decreased by the addition of a small amount of hydrazine in the presence of gamma radiation at room temperature. (author)

  8. Irradiation of hydrophobic coating materials by gamma rays and protons: space applications

    Science.gov (United States)

    Taylor, Edward W.; Pirich, Ronald G.; Weir, John D.; Leyble, Dennis; Chu, Steven; Taylor, Linda R.

    2010-09-01

    The responses of hydrophobic silicone-based coatings following irradiation by Co-60-gamma-rays are reported. The dimethylsilicone (DMS) resin coatings consisted of neat samples and samples incorporating semiconductor metal oxide (SMO) irradiated at photon energies of 1.17 and 1.33 MeV. Pre-and post-irradiation measurements indicated that at a total dose of ~ 185 krad(Si) there was no significant change to the coating static hydrophobic contact angles, surface molecular structure and biocide neutralization efficiency. The data was compared with previously irradiated and reported DMS/SMO coatings at a proton fluence of ~1.5 x 1012 p/cm2. Potential space applications for the radiation resistant coating self- cleaning properties are presented as well as a discussion of other environmental testing required to qualify the technology for transition to photonic space applications.

  9. Studies on the preparation and uses of Co-60 gamma-ray irradiated natural latex

    International Nuclear Information System (INIS)

    The properties are described of low-ammonia latex concentrates produced by gamma-ray irradiation (0.5 to 2.0 Mrad dose) in the presence of carbon tetrachloride or chloroform as sensitizer. Dipping trails with irradiated concentrates and irradiated field latex, for the preparation of condoms and medical gloves, gave products with high ultimate elongation, low modulus, and high permanent set. A change from straight dipping to coagulant dipping and a heat treatment after drying resulted in improved physical properties. A notable feature of products prepared from these materials is their purity, i.e., low content of rubber chemicals. An economic disadvantage, at the present time, is the high initial cost of the irradiation equipment

  10. Effect of cobalt-60 gamma-ray irradiation on beans (Phaseolus vulgaris L.) of huasteco variety

    International Nuclear Information System (INIS)

    Bean seeds, Huasteco variety, were irradiated at 10, 20, 30 and 40 kR in a cobalt-60 gamma-ray source. Non-irradiated seeds were used as control. Irradiated and non-irradiated seeds were planted under greenhouse conditions using a random design and a population of 200 plants per treatment for both first and second generations (M1 and M2). The characters studied were; germination, survival, morphological changes of leaves and stem, change in seed coat colour, flowering, height, stem diameter, number of internodes, number of pods and number of seeds per pod. General plant behaviour was also observed to detect changes on a genic or chromosomic level. (M.A.C.)

  11. Gamma-ray irradiation on polystyrene in the presence of crosslinking agents

    International Nuclear Information System (INIS)

    The radiation induced crosslinking of polystyrene is difficult because of its aromatic units, and the polymer degrades when irradiated in air. Therefore, the authors studied the effects of gamma-ray irradiation on polystyrene in the presence of polyfunctional monomers such as trimethyl propanetrimethacrylate (TMPTM), dimethyleneglycol bisallycarbonate (DEGBAC), etc. These monomers readily polymerize by irradiation with small dose. When polystyrene was mixed with 20% by weight of TMPTM, the toluene insoluble polymer obtained after the irradiation with a dose of 10 Mrad had a polystyrene TMPTM ratio of 1 and with a dose of 20 Mrad, the radio became 6. Since TMPTM alone polymerizes with a dose much smaller than these doses, it is likely that the chain breaking and recombination between polystyrene and poly TMPTM takes place. In the case of DEGBAC, the dose required for crosslinking of polystyrene was higher than that with TMPTM. The relationships between doses and radiochemical yields for gelation and degradation for various polyfunctional monomers are presented

  12. Influence of gamma-ray irradiation on Faraday effect of Cu-doped germano-silicate optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngwoong; Ju, Seongmin; Jeong, Seongmook; Jang, Myoung-Jin [Department of Physics and Photon Science, School of Information and Communications, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro, Buk-Gu, Gwangju 500-712 (Korea, Republic of); Kim, Jong-Yeol; Lee, Nam-Ho; Jung, Hyun-Kyu [Nuclear Convergence Technology Development Department, Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon (Korea, Republic of); Han, Won-Taek, E-mail: wthan@gist.ac.kr [Department of Physics and Photon Science, School of Information and Communications, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro, Buk-Gu, Gwangju 500-712 (Korea, Republic of)

    2015-02-01

    Influence of gamma-ray irradiation on the Faraday effect of the Cu-doped germano-silicate optical fiber was investigated. The Verdet constant of the gamma-ray irradiated optical fiber at 660 nm was measured to be 3.07 rad T{sup ?1} m{sup ?1}, 1.46 times larger than that of before the irradiation at total dose of 1200 Gy. Cu-related radiation-induced defect centers and Cu metal particles which were reduced from Cu{sup 2+} ions by the irradiation are thought to be responsible for the increase in the Verdet constant of the optical fiber.

  13. Generation of the fullerene oxide anion by the gamma ray irradiation to the organic matrix at low temperature

    International Nuclear Information System (INIS)

    The gamma ray irradiation was performed to the isomers of separated fullerene oxides dispersed in the low temperature organic matrix. The fullerene oxide anions generated during the irradiation are analyzed by a spectroscopic method. The relation between the structure of each isomer and the process of the isomer formation during the irradiation is studied. The near-infrared absorption spectra of the fullerene oxide isomers are found to be changed by the gamma ray irradiation at 77 K, which are dispersed in methyl tetrahydroxyfuran. The generation of the fullerene oxide anion was expected to be controlled by the electron affinity of the oxide isomers. (H. Katsuta)

  14. Influence of gamma-ray irradiation on Faraday effect of Cu-doped germano-silicate optical fiber

    International Nuclear Information System (INIS)

    Influence of gamma-ray irradiation on the Faraday effect of the Cu-doped germano-silicate optical fiber was investigated. The Verdet constant of the gamma-ray irradiated optical fiber at 660 nm was measured to be 3.07 rad T?1 m?1, 1.46 times larger than that of before the irradiation at total dose of 1200 Gy. Cu-related radiation-induced defect centers and Cu metal particles which were reduced from Cu2+ ions by the irradiation are thought to be responsible for the increase in the Verdet constant of the optical fiber

  15. Life shortening, tumor induction, and tissue dose for fission-neutron and gamma-ray irradiations

    International Nuclear Information System (INIS)

    The primary focus of this program is to obtain information on the late effects of whole body exposure to low doses of a high linear-energy-transfer (LET) and a low-LET ionizing radiation in experimental animals to provide guidance for the prediction of radiation hazards to man. The information obtained takes the form of dose-response curves for life shortening and for the induction of numerous specific types of tumors. The animals are irradiated with fission neutrons from the Janus reactor and with 60Co gamma rays, delivered as single, weekly, or duration-of-life exposures covering the range of doses and dose rates. 6 refs

  16. Ageing evaluation for low voltage cables with low dose rate gamma ray irradiation accelerated ageing tests

    Energy Technology Data Exchange (ETDEWEB)

    Tatsuoka, T.; Ibusuki, Y.; Furuhashi, Y.; Takamori, K.; Tezuka, H. [RD Center, Tokyo Electric Power Company (Japan); Hashimoto, A. [Nuclear Asset Management Department, Tokyo Electric Power Company (Japan)

    2011-07-01

    Low voltage cables are installed in nuclear power plants to supply electric power and signals. Long-term reliability of cables in nuclear power plants is expected from some experimental results reported in Institute of Electrical Engineering of Japan (IEEJ). Significant ageing of real cables has never been observed in nuclear power plants. However, some cables may get oxidation slowly under irradiation and thermal environments during normal operation. For lifetime extension of nuclear power plants, cable ageing evaluation has become very important. To optimize lifetime prediction method of cables and to understand cable ageing mechanism, ageing evaluation of low voltage cables, especially insulators, with gamma ray irradiation and thermal accelerated ageing tests were conducted. Two kinds of gamma ray irradiation and thermal accelerated ageing tests with low dose rate (around 3.5 Gy/h) and low temperature (room temperature and 80 C) and two kinds of thermal accelerated ageing tests at 80 C in different oxygen concentration (5 and 20 % O{sub 2}) were performed, respectively. The accelerated ageing tests conditions are relatively milder than those had conducted by many researchers for many years. The studies are focused on Flame Retardant Ethylene-propylene Rubber (FR-EPR) insulators and Cross-linked Polyethylene (C-PE) insulators. Insulators had almost no indication of ageing after several thousand hours of the accelerated ageing tests. (authors)

  17. Influence of gamma rays irradiation to chlorphyriphos insecticides residues in grapes (vitis vinifera L.)

    International Nuclear Information System (INIS)

    Simulation methods to determination of chlorphyriphos insecticides residue in grapes cause effect gamma rays, was done. Fruits of grapes soaked with chlorpyriphos insecticide solution high level concentrated (100 ppm; 200 ppm; and 300 ppm) for 3 (three minutes). The treatment of the sample was direct of extraction after soaks; extract after storage for one week after soak, and extract after soak after storage for one week after irradiation at 0.5 kGy; 1.0 kGy; and 1.5 kGy dose. Extraction methods using ethyl acetate solvent, and using sodium sulphate as to dryed water level in grapes, and then extractan was injected to chromatography gas use electron capture detector. The result indicated that occur of descent of chlorpyrifos residues from eachs soaked consequence at storage for one week was amount 7,55; 8,42; and 18,88% respectively, while of consequence irradiation of gamma ray at 0,5 kGy doses, will be descent of chlorpyrifos residues in amount 13,90; 19,16; and 52,79% respectively, and at 1,0 kGy doses irradiation will be descent in amount 34,45; 36,15 and 49,79%, respectively. (author)

  18. Ageing evaluation for low voltage cables with low dose rate gamma ray irradiation accelerated ageing tests

    International Nuclear Information System (INIS)

    Low voltage cables are installed in nuclear power plants to supply electric power and signals. Long-term reliability of cables in nuclear power plants is expected from some experimental results reported in Institute of Electrical Engineering of Japan (IEEJ). Significant ageing of real cables has never been observed in nuclear power plants. However, some cables may get oxidation slowly under irradiation and thermal environments during normal operation. For lifetime extension of nuclear power plants, cable ageing evaluation has become very important. To optimize lifetime prediction method of cables and to understand cable ageing mechanism, ageing evaluation of low voltage cables, especially insulators, with gamma ray irradiation and thermal accelerated ageing tests were conducted. Two kinds of gamma ray irradiation and thermal accelerated ageing tests with low dose rate (around 3.5 Gy/h) and low temperature (room temperature and 80 C) and two kinds of thermal accelerated ageing tests at 80 C in different oxygen concentration (5 and 20 % O2) were performed, respectively. The accelerated ageing tests conditions are relatively milder than those had conducted by many researchers for many years. The studies are focused on Flame Retardant Ethylene-propylene Rubber (FR-EPR) insulators and Cross-linked Polyethylene (C-PE) insulators. Insulators had almost no indication of ageing after several thousand hours of the accelerated ageing tests. (authors)

  19. Effects of gamma-ray irradiation on discharge characteristics of organic insulating materials

    International Nuclear Information System (INIS)

    Organic insulating materials have been widely used as insulators for electrical elements in various environmental conditions. These investigations are further enhanced due to the increasing of organic insulating materials being used in radiation environment of space and nuclear power facilities. This paper describes the effects of gamma-rays irradiation on the discharge characteristics of organic insulating materials. The samples of modified polyphenylene oxide, polybutylene, epoxy resin and polybutylene terephthalate which were irradiated in air up to 100 kGy and 1 MGy with a dose rate of 10 kGy/h using a 60Co gamma source. The experiment was carried out on the sample surface by applied a dc impulse voltage between a plate and needle electrode. The solution droplet was placed on the plate of sample in contact with the needle electrode. The total dose effects on the discharge quantity, contact angles and extending length of droplet have been studied. As the total doses are increased, the tendency of discharge quantity decreased with modified polyphenylene oxide, polybutylene and epoxy resin, on the other hand the discharge quantity increases with polybutylene terephthalate. The author found that the effects of gamma-rays irradiation on surface discharging quantity are due to radiation-induced degradation and cross-linking of organic insulating materials. (author)

  20. Evaluation of the effect of gamma-ray irradiation on starch by near-infrared spectroscopy

    International Nuclear Information System (INIS)

    In order to evaluate the effect of gamma-ray irradiation on starch, near-infrared absorption spectra of four groups of starch samples, control, 10, 20 and 30 kGy irradiated, were measured. By the preliminary analysis, it was revealed that 1 702 and 2 100 nm were effective in predicting the irradiation dose on starch. On the other hand, samples were divided into calibration and validation set. The multi-regression analysis of the calibration set was carried out with adopting 1702 or 2100nm as the first wavelength, and the resulting calibration curves were named calibration A and B. Using these calibration curves, the irradiation dose of the validation set was predicted. Although the accuracy of the prediction was poor, it seemed that the non-irradiated and the irradiated samples could be discriminated by an appropriate borderline. Therefore, a new irradiation index was defined as non-irradiated = 0 and irradiated = 1. In the same way as the case of four groups, calibration C and D, in addition, calibration E, which using 1702 nm only, were developed and the irradiation index of the validation set was predicted. Although there were a few samples that could not be accurately predicted with calibration C and D, there was only one wrong discrimination with calibration E and its prediction accuracy was 96.2%

  1. Dose rate variation of traveling source cage of a gamma-ray irradiation equipment

    International Nuclear Information System (INIS)

    Dose rate variation of traveling soure cage of a gamma-ray irradiation equipment is measured by using silicon semiconductor detector. The ratio α of average dose rate during the traveling to steady dose rate is evaluated at each sample position. In the neighborhood of the source the value of α varies considerably both with the distance R from the source center and the height H from the irradiation table, while at any H it shows alomst no change for R longer than 40 cm. From these evaluated values of α it is estimated that the error in exposure caused by the dose rate variation during the traveling of the source cage is more than 5% for the irradiation time within 300 sec. (author)

  2. Thermal, tensile and rheological properties of low density polyethylene (LDPE) processed irradiated by gamma-ray

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate structural changes of low density polyethylene (LDPE) modified by ionizing radiation (gamma rays). The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. The samples were prepare in hydraulic press in temperature 180 deg C after was irradiated with gamma source of 60Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h in inert atmosphere. The changes in molecular structure of LDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere. (author)

  3. Thermal, tensile and rheological properties of low density polyethylene (LDPE) processed irradiated by gamma-ray

    Energy Technology Data Exchange (ETDEWEB)

    Ferreto, Helio F.R.; Oliveira, Ana C.F. de; Parra, Duclerc F.; Lugao, Ademar B., E-mail: hferreto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The aim of this paper is to investigate structural changes of low density polyethylene (LDPE) modified by ionizing radiation (gamma rays). The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. The samples were prepare in hydraulic press in temperature 180 deg C after was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h in inert atmosphere. The changes in molecular structure of LDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere. (author)

  4. Behavioral changes in rats prenatally irradiated with low dose of gamma-rays

    International Nuclear Information System (INIS)

    In this work, the effects of prenatal gamma-irradiation on behavior in adult Sprague-Dawley rats were studied. Four months old female rats were irradiated with a dose of 1 Gy of gamma-rays on day 15 of gestation. The offspring of irradiated mothers (n=26) and that of control, non-irradiated mothers (n=36) of both sexes at the age of 3 month were tested in Morris's water maze and in open field test. All experimental groups showed a tendency to shortening the time needed to reach the platform in each trial in Morris water maze. Statistically significant difference between irradiated and control rats was detected only in males on 3rd experimental day. The ability to remember the position of the platform was not altered in irradiated animals after a 4 day pause. In open field test, statistically significant differences in comparison with controls were detected in number of squares entered and in crossings of the central square (P ≤ 0.05) in males. These findings suggest, when comparing with results of other authors, that irradiation effects on postnatal behavior in rats are extremely dependent on the time point of irradiation and that a correlation exist between the developmental stage of the individual brain structures at time of irradiation and the late behavioral effects. (authors)

  5. Mutation induction in chrysanthemum through in vitro acute and chronic irradiations with gamma rays

    International Nuclear Information System (INIS)

    In Vitro culture of chrysanthemum variety 'Reagan Dark Splendid' was established using explants from axillary buds and ray florets. Shoots produced in vitro culture from axillary buds were irradiated with acute gamma rays of 30 Gy. While multiple shoots produced from in vitro culture of ray florets were irradiated with chronic gamma rays of 112 and 140 Gy. The irradiated shoots were then multiplied two times by single-node cuttings from M1V1 to M1V3. Controls and irradiated shoots were rooted, transferred to soil in the greenhouse, and finally transplanted in the field. Observation and measurement were made at flowering time for height, number of nodes per plant and flower colour mutation frequency. Flower colour mutation frequency among the irradiated plants with 30, 112 and 140 Gy was 8.2, 9.3 and 15.3% respectively. Eleven variants were selected among the M1V3 plants from 30 Gy dose treatment. Selected variants had flower colour varying from red, red-purple and yellow-orange. Nine variants were selected among the M1V3 plants from 112 Gy dose treatment. Selected variants had flower colour varying from red, red-purple, purple and yellow-orange. Sixteen variants were selected from 140 Gy dose treatment. They had flower colour varying from red-purple, purple, orange-red, yellow-orange and yellow. These variants were multiplied through in vitro culture as well as by conventional cutting. They will be evaluated for their performance, stability and uniformity in the field, and for market value during the next planting season. (author)

  6. Effect of gamma rays on sex ratio, emergence and lifespan of cucurbits fruit fly dacus ciliatus (low) irradiated as pupae

    International Nuclear Information System (INIS)

    The result showed the pupae at the age 1 or 2 days old was very sensitive to all doses of gamma rays, the percentage of adults emerged was zero at the dose of 45 gray and highest and the gigh percentage of adults emergence was recorded when the pupae irradiated at five days ald and the mean percentage of emerged adults was approximated with that of the control group. This study also showed that there was an effect of gamma radiation on the average percentage of deformed at adult stage and it was about 1:1 (male: female). On the other hand, the mean lifespan of females and mice s adult were decreased as the dose of gamma rays increases and the pupae irradiated at youngest ages. The longest life span of females was recorded when the pipa irradiated at five days old with any of the gamma rays dose. (Author)

  7. Relationship between free volume and mechanical properties of polyurethane irradiated by gamma rays

    International Nuclear Information System (INIS)

    Polyurethane was irradiated at various gamma radiation doses up to 1,000 kGy at room temperature in nitrogen. Positron annihilation lifetime spectroscopy, tensile test and dynamic mechanical analysis were used to find the relationship between free volume and mechanical properties. An increase of the free volume fraction in soft segments (SS) and a decrease of the free volume fraction in hard segments (HS) during gamma radiation was observed and analyzed. The results showed that HS in polyurethane had the excellent resistance to gamma radiation, whereas SS had a tendency to degrade. The reason for the decrease of the strain at break and the ultimate tensile strength was analyzed, which showed the changes in the mechanical properties of polyurethane irradiated by gamma rays were mainly determined by the changes of free volume in SS. If the resistance properties of polyurethanes exposed to radiations need to be improved, SS should be paid more attention to. (author)

  8. Survival of embryo irradiated with gamma rays by embryo culture in Brassica pekinensis Rupr

    International Nuclear Information System (INIS)

    The effect of irradiation on the survival rates and embryonic development of Brassica pekinensis RUPR. (Varieties; Kashin, Kohai 65 nichi and kairyochitose) was investigated. The purpose of this study was to seek ways of increasing the survival rates of embryos such as B.oleracea obtained through embryo culture techniques after irradiation doses affecting seed fertility and germination, for the purpose of increasing mutation rates. Embryos at different developmental stages ranging from the globular to the early heart stages were irradiated with 20 KR of gamma rays at the daily rate 0L 20 KR or 10 KR (Fig.1 and Table 1). The embryos were excised from ovules 4 to 10 days after irradiation and cultured on White's medium. The shooting and rooting rates on the 34th day of culture were higher at the dose of 10 KR/day than 20 KR/day and were lower when the materials were irradiated at the young embryonic stage (Table 3). Varietal differences in the shooting and rooting rates were also observed. The irradiated embryos survived mainly in the state of callus. It was concluded that the embryo culture technique was successful when applied to irradiated embryos excised at the young embryonic stage and that the technique affected B.pekinensis less than B.oleracea

  9. Biochemical and pharmacological characterization of irradiated crotamine by gamma rays of 60Co

    International Nuclear Information System (INIS)

    The serum production in Brazil, the only effective treatment in cases of snakebites, uses horses that although large size, have reduced l lifespan compared with horses not immunized. Ionizing radiation has been shown as an excellent tool in reducing the toxicity of venoms and toxins isolated, and promote the achievement of better immunogens for serum production, and contributing to the welfare of serum-producing animals. It is known, however, that the effects of ionizing radiation on protein are characterized by various chemical modifications, such as fragmentation, cross-linking due to aggregation and oxidation products generated by water radiolysis. However, the action of gamma radiation on toxins is not yet fully understood structurally and pharmacologically, a fact that prevents the application of this methodology in the serum production process. So we proposed in this paper the characterization of crotamine, an important protein from the venom of Crotalus durissus terrificus species, irradiated with 60Co gamma rays. After isolating the toxin by chromatographic techniques and testing to prove the obtaining of pure crotamine, it was irradiated with gamma rays and subjected to structural analysis, Fluorescence and Circular Dichroism. Using high hydrostatic pressure tests were also conducted in order to verify that the conformational changes caused by radiation suffer modifications under high pressures. From the pharmacological point of view, muscle contraction tests were conducted with the objective of limiting the action of crotamine in smooth muscle as well as the change in the action of toxin caused structural changes to the front. Analysis of Circular Dichroism and Fluorescence showed changes in structural conformation of crotamine when subjected to gamma radiation and that such changes possibly occurring in the secondary and tertiary structure of the protein. The observed in pharmacological tests showed that the irradiated crotamine was less effective in lowering the vas deferens twitch in rats in comparison to native crotamine. In addition, the behavior of irradiated toxin in tonic contraction, modulated by noradrenaline, was different from that observed for the native toxin. (author)

  10. Chemical and Biological Studies on Cumin Fruits Irradiated by GAMMA Rays for Conservation

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the effect of different doses of gamma irradiation (0, 5, 10 and 15 KGy) and different storage periods (0, 3 and 6 months) in different package materials (cotton or polyethylene bags) on essential oil quality and chemical composition of cumin (Cuminum cyminum) fruits. On the other hand antimicrobial activity of treated cumin fruits essential oil and its extracts at 0, 5000, 10000, 20000 and 40000 ppm were investigated. Results showed that the highest essential oil % was obtained from fruits stored for 3 months in cotton bag without gamma irradiation. Concerning the effect of essential oil as antimicrobial agent, the highest antibacterial activity was obtained by essential oil isolated from irradiated polyethylene packed fruits at 5 KGy then stored for 3 months (Staphylococcus aureus) or irradiated polyethylene packed ones at 15 KGy without storage (Salmonella typhimurium). On the other hand, the highest antifungal activity against Aspergillus niger and Penicillium digitatum was obtained by essential oil isolated from unirradiated packed in polyethylene fruits then stored for 6 months. Non-stored packed in cotton bag fruits irradiated with gamma rays at 10 KGy produced essential oil with highest antiyeastal activity. Cumin fruits extract at 40000 ppm when combined with different treatments presented the highest antimicrobial activity (represents as inhibition zone) against all studied microbes except with P. digitatum. Cumin extract at 40000 ppm when extracted from irradiated packed fruits in polyethylene bags with gamma rays at 5 KGy without storage or with 6 months storage or irradiated at 15 KGy of packed fruits in cotton bag with storage for 3 months presented the highest significant inhibition zones against S. aureus. The same concentration of extracted cumin from uni radiated packed in cotton bag fruits and storage for 6 months presented the highest inhibition zone of S. typhimurium. Also, with the same concentration, extracted cumin from irradiated at 10 KGy of packed in cotton bag fruits without storage or in polyethylene and stored for 3 months presented the highest inhibition zones of A. niger. Cumin extract at 5000 ppm when extracted from irradiation at 10 KGy of packed in cotton bag fruits and stored for 3 months presented the highest values of P. digitatum. On the other hand, the superior concentration of cumin extract (40000 ppm) presented the highest antiyeastal effect when extracted from irradiated packed in polyethylene fruits at 10 KGy and stored for 6 months.

  11. A comparative experiments for tube agglutination test of pullorum antiserum with gamma ray Co60 irradiated salmonella pullorum

    International Nuclear Information System (INIS)

    An agglutinability between naturally infected positive chicken serum of pullorum disease and hyperimmunized rabbit antiserum was compared. And the following results were obtained and summarized. On the agglutinability, Salmonella pullorum antigen which irradiated gamma-ray was better than another both formalized and heated antigen. Time of judgemented as positive titer in the tube agglutination test to the naturally infected positive chicken serum was it most suitable for 12 hours at 37C. Agglutination titer of positive immune chicken serum against gamma-ray irradiate Salmonella pullorum were as 320 approximately 640x. (author).

  12. Gamma-Ray Irradiation Experiments of Collimator Key Components for the 3GeV-RCS of J-PARC

    CERN Document Server

    Kinsho, Michikazu; Masukawa, Fumihiro; Ogiwara, Norio; Takeda, Osamu; Yamamoto, Kazami

    2005-01-01

    The turbo molecular pump and the stepping motor which can be operated exposed to high radiation has been under development at JAERI for use in the 3GeV-RCS of the J-PARC. In order to determine the extent of radiation damage to those instruments, gamma-ray irradiation testing was performed at JAERI. It was succeed that the turbo molecular pump and stepping motor could operate properly when given an absorption dose more than 15 MGy in a gamma-ray irradiation environment.

  13. Mechanical properties of molded specimen from polypropylene film irradiated with gamma rays in acetylene gas atmosphere

    International Nuclear Information System (INIS)

    Bulky materials reclaimed from waste plastics are not adequate to use as structual materials since mechanical properties of them are relatively low. In the present work polypropylene (PP) films, which are a potential main component of waste plastics in near future, were irradiated with gamma rays in acetylene gas atmosphere and then were injection molded to PP test specimens to measure its mechanical properties. The flexural strength and modulus of elasticity in bending have been found to increase with irradiation dose. Those values reach the maximum at the irradiation dose of 40-80 kGy. In the case of the gas pressure of 199 kPa and the irradiation of 57 kGy, the observed strength and modulus of elasticity of the PP specimen are 59 MPa and 2,050 MPa, respectively, which are 1.5 times and 1.7 times as large as those of unirradiated PP. The tensile properties of the PP Specimen also are improved by 1.4 times of unirradiated PP. The acetylene gas pressure has little influence to improve the properties in a range above 100 kPa. The injection molding after the irradiation is considered to be effective to improve the mechanical properties of the PP specimen since the heating and mixing of irradiated films enhance the cross-links of acetylene to PP structures and the network formation. (author)

  14. Effects of gamma Rays Irradiation on resistance of Pseudomonas aeruginosa in various condition

    International Nuclear Information System (INIS)

    The investigation of gamma tays 60Co irradiation effect on resistance of bacteri P.aeruginosa has been done.The objective of the research was to know the D10 value of bacteria P.aeruginosa. By using of distilled water,talc and peanut powder as carrier in dry,wet,O2 and N2 condition the bacteria of P.aeruginosa were irradiated on gamma rays of 60Co with dose of O to 2.5 kGy,and with dose rate of 5 and 10 kGy/h.After irradiation the bacteria of P. aeruginosa were cultured in media of the Tryptone Soya Agar and incubatedat temperature of 322oC for 3 days. The survival colonies were calculated,and the data were used to make the curve and to determine the D10 value. The results of the experiments showed that D10 value of irradiated bacteria of P.aeruginosain the disitilled water,talc and peanut powder as carrier were not high significant.Nevertheless the D10 value of the irradiated at dose rate 10kGy/h show more higher tendency than at dose rate 5kGy/h. The D10 value of irradiated bacteria in the N2 condition was higher,if compared with in the O2 condition

  15. EFFECT OF GAMMA RAY IRRADIATION ON INTERLAMINAR SHEAR STRENGTH OF GLASS FIBER REINFORCED PLASTICS AT 77 K

    International Nuclear Information System (INIS)

    It is known that an organic material is damaged by gamma ray irradiation, and the strength after irradiation has dependence on the gamma ray dose. These issues are important not only to make global understanding of electric insulating performance of glass fiber reinforced plastics (GFRP) under irradiation condition but also to develop new insulation materials. This paper presents the dependence of fracture mode and interlaminar shear strength (ILSS) on the material and the gamma ray irradiation effect on the fracture mode and the ILSS. 6 mm radius loading nose and supports were used to prompt ILS fracture for a short beam test. A 2.5 mm thick small specimen machined out of a 13 mm thick G-10CR GFRP plate (sliced specimen) showed lower ILSS and translaminar shear (TLS) fracture, although the same size specimen prepared from a 2.5 mm G-10CR GFRP plate (non-sliced specimen) showed ILS fracture and the higher ILSS. Both type of specimens showed the degradation of ILSS after gamma ray irradiation. The fracture mode of the non-sliced specimen changed from ILS to TLS fracture and no bending fracture was observed. The resistance to shear deformation of glass cloth/epoxy laminate structure would be damaged by the irradiation

  16. biotechnological studies on the irradiated potato (solanum tuberosum) with gamma rays

    International Nuclear Information System (INIS)

    Bacterial wilt or brown rot disease caused by Ralstonia solanacearum causes extensive annual losses of different crops especially potato crop. It is considered as one of the limiting factors for potato production and exportation in Egypt. Therefore, the main purposes of this study were to investigate the effect of gamma rays on two potato cultivars (Diamant and Spunta). And, to obtain new genotypes of potato resistant to bacterial wilt disease. This study was carried out in the field and Biotechnology laboratory of the Plant Res. Dept., Nuclear Res. Center, Inshas, Egypt and Genetics Dept., Faculty of Agricultural., Cairo Univ., during 2008-2011. In the field experiment, dry tubers of potato cultivars were irradiated by different doses of gamma rays (20, 30 and 40 Gy) to study the effect of gamma rays on the vegetative and yield traits. The results showed that there are no significant differences between cultivars for all studied traits except a number of tubers per plant trait. Also, there are only highly significant and significant differences between treatments for weight of tubers per plant and number of tubers per plant traits, respectively. However, there are only significant differences between the interactions of cultivars and treatments for plant height and weight of tubers per plant traits. Six genotypes were selected from M1V2 generation depending on high yield for RAPD analysis to determine their genetic variability from its parents at molecular level using 11 primers. The results of RAPD analysis showed that 11 primers generated 56 distinct bands of which 31 (55.4%) were considered as polymorphic. The similarity indices of six genotypes of potato and its parents ranged from 70 to 91%. The highest genetic similarity 91% was found between D20 genotype and its parent D0 (Diamant control). On the other hand, the lowest genetic similarity 70% was found between S30, S40 genotypes and its parent S0 (Spunta control). In the artificial infection experiment under in vitro condition, the irradiated and non-irradiated plantlets of potato were cultured on medium inoculated with local virulent isolate of R. solanacearum. The results showed that all in vitro plantlets of the treatments in Diamant and Spunta cultivars were susceptible except S20 treatment was resistant to the infection with R. solanacearum. Protein analysis showed that S20 genotype (resistant mutant) displayed 2 negative unique bands that may be responsible for resistance to R. solanacearum.

  17. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.

    2011-09-22

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Polymeric materials become damaged by exposure over time to ionizing radiation. Despite the limited lifetime, polymers have unique engineering material properties and polymers continue to be used in tritium handling systems. In tritium handling systems, polymers are employed mainly in joining applications such as valve sealing surfaces (eg. Stem tips, valve packing, and O-rings). Because of the continued need to employ polymers in tritium systems, over the past several years, programs at the Savannah River National Laboratory have been studying the effect of tritium on various polymers of interest. In these studies, samples of materials of interest to the SRS Tritium Facilities (ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, Teflon{reg_sign}), Vespel{reg_sign} polyimide, and the elastomer ethylene propylene diene monomer (EPDM)) have been exposed in closed containers to tritium gas initially at 1 atmosphere pressure. These studies have demonstrated the degradation of properties when exposed to tritium gas. Also, the radiolytic production of significant amounts of hydrogen has been observed for UHMW-PE and EPDM. The study documented in this report exposes two similar formulations of EPDM elastomer to gamma irradiation in a closed container backfilled with deuterium. Deuterium is chemically identical to protium and tritium, but allows the identification of protium that is radiolytically produced from the samples. The goal of this program is to compare and contrast the response of EPDM exposure to two different types of ionizing radiation in a similar chemical environment.

  18. Technical data on electron beam and gamma ray irradiation facilities. Electron accelerator and 60Co irradiation facility

    International Nuclear Information System (INIS)

    Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), have an electron beam facility employing an industrial-scale electron accelerator with the maximum acceleration voltage of 2 MV, and world-class cobalt 60 gamma ray irradiation facilities consisting of 3 buildings and 8 irradiation rooms which cover 6 decade of dose rate range. These facilities are in operation as a world Center of Excellence, widely for users inside and outside of JAEA to perform research and testing or collaborative work on multipurpose such as material developments, environmental technology, and biotechnology. The present report describes characteristics of irradiation field, auxiliary utilities in irradiation rooms, and basic data for irradiation and dose evaluation of a sample. (author)

  19. Effects of gamma-ray and high energy carbon ion irradiation on swimming velocity of Euglena gracilis

    Science.gov (United States)

    Sakashita, T.; Doi, M.; Yasuda, H.; Fuma, S.; Hder, D.-P.

    The effects of gamma-ray and high energy carbon ion irradiation on the swimming velocity of the photosynthetic flagellate Euglena gracilis strain Z were studied, focusing on a dose-effect relationship. Cells were exposed to 60Co gamma-rays at 6 doses of 10, 15, 20, 40, 100 and 200 Gy for water, and also to 290 MeV/amu carbon ions from the Heavy Ion Medical Accelerator in Chiba at 7 doses (5, 10, 15, 20, 50, 100 and 200 Gy for water). The swimming velocity was measured by a biomonitoring system, called ECOTOX. The swimming velocities of Euglena gracilis cells were significantly decreased by >40 Gy gamma-rays and >5 Gy carbon ions, respectively. The 50% effective doses for inhibition, 344 Gy (gamma-rays) and 131 Gy (290 MeV/amu carbon ions), were estimated from the best fit to data of the logistic model. The relative biological effectiveness (2.60.4) was calculated by the ratio of 50% effective doses. The inhibition of the swimming velocity of the cells irradiated with gamma-rays was still present after 3 days, while recovery of the swimming velocity was shown in the cells exposed to 290 MeV/amu carbon ions. It is suggested that ionizing radiation inhibits ATP production and/or increases frictional drag on beating of the flagellum, thus decreasing swimming velocity.

  20. Stability of polyvinylpolypyrrolidone against gamma-ray irradiation in HNO3 media

    International Nuclear Information System (INIS)

    Polyvinylpolypyrrolidone (PVPP) is a resin with adsorption selectivity for U(VI) in HNO3 media. The stability of this resin has been examined against gamma-ray irradiation using HNO3 solutions of various concentrations. Samples of PVPP immersed in HNO3 solutions up to 6 moldm-3 (=M) were irradiated by a 60Co source at 3.6 kGyh-1 to reach 0.90 MGy at room temperature under ambient atmosphere. As a result, no clear decrease in the capacity for U(VI) when added in 3 M HNO3 was observed for any samples, or rather the capacity was found to increase by approximately 50 % for PVPP irradiated in 6 M HNO3. It was indicated from some spectroscopic analyses of the irradiated samples that the irradiation causes the cleavage of the pyrrolidone ring of PVPP. This occurs by the addition of an oxygen atom originating from HNO3, followed by the formation of straight-chain groups with multiple coordinative atoms by the successive addition of oxygen, finally leading to the generation of a primary-amine-type weakly-basic anion exchange resin. The increase in the U(VI) capacity would be due to the formation of the straight-chain groups. However, such structural changes were not observed by heating at 323 K in up to 6 M HNO3 for 20 days. Thus, it was shown that PVPP is a heat-resistant resin. (author)

  1. Gamma rays irradiation process on a restored painting from the XVII century

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, Marcia M. [MRIZZO Laboratorio de Conservacao e Restauracao de Bens Culturais Ltda., Sao Paulo, SP (Brazil)], e-mail: mrizzo@mrizzo.com.br; Machado, Luci D.B.; Rela, Paulo R.; Kodama, Yasko [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], e-mail: prela@ipen.br, e-mail: lmachado@ipen.br, e-mail: ykodama@ipen.br

    2009-07-01

    The aim of this work is to emphasize the importance of a previous study of the materials composition and behavior of any art work which will be treated by gamma radiation, as well as to use complementary procedures to prevent recontamination after the treatment, since this is a non residual method. As an example the object of study is a Peruvian painting from the 17th century, which has been restored, contaminated by mould, treated by gamma rays, put in a hermetic acrylic box and showed microorganisms growth after six years. A new treatment was performed using the same process and a complementary method using cloistering with anoxia atmosphere to prevent recontamination. Before the first irradiation the influence of irradiation process on the original painting and on the materials used in the restoration process were investigated. These data were extremely important in the decision of the use gamma irradiation again on the same art work. The results obtained allowed concluding that the irradiation with the recommended dose of 6.0 kGy (at the first time) was not sufficient to kill all the fungi specimens in the art work. On the other hand the irradiation with the dose of 6.0 kGy (at the first time) and 9.0 kGy (at the second time), according to the literature, would not damage the restored painting. (author)

  2. Gamma rays irradiation process on a restored painting from the XVII century

    International Nuclear Information System (INIS)

    The aim of this work is to emphasize the importance of a previous study of the materials composition and behavior of any art work which will be treated by gamma radiation, as well as to use complementary procedures to prevent recontamination after the treatment, since this is a non residual method. As an example the object of study is a Peruvian painting from the 17th century, which has been restored, contaminated by mould, treated by gamma rays, put in a hermetic acrylic box and showed microorganisms growth after six years. A new treatment was performed using the same process and a complementary method using cloistering with anoxia atmosphere to prevent recontamination. Before the first irradiation the influence of irradiation process on the original painting and on the materials used in the restoration process were investigated. These data were extremely important in the decision of the use gamma irradiation again on the same art work. The results obtained allowed concluding that the irradiation with the recommended dose of 6.0 kGy (at the first time) was not sufficient to kill all the fungi specimens in the art work. On the other hand the irradiation with the dose of 6.0 kGy (at the first time) and 9.0 kGy (at the second time), according to the literature, would not damage the restored painting. (author)

  3. Radiation degradation of microchemical chips and capillary tubes by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Analytical equipment, which consists of a microchemical chip and a desktop-sized thermal lens microscope (DT-TLM), is being developed to analyze solutions in PUREX reprocessing of spent nuclear fuels. Radiation degradation by gamma-rays of the microchemical chip and capillary tubes used in this equipment were studied. The decreased thermal lens signal of a colored microchemical chip made of Pyrex (Corning no.7740) glass by the irradiation can be corrected by using empirical correlations of the light transmittance. The usable dose of the EXLON PFA capillary tube was less than 30 kGy. The microchemical chip made of Pyrex(Corning no.7740) glass and the EXLON PFA capillary tubes can be applied to the analyses of high radioactivity samples since the sample quantity required for analysis is very small. Radiation degradation of the microchemical chip made of synthetic quartz (SUPRASIL-P) and the VICTREX PEEK capillary tubes was not observed for the dose studied here. (author)

  4. Evaluation of some selected vaccines and other biological products irradiated by gamma rays, electron beams and X-rays

    International Nuclear Information System (INIS)

    Molecular sizing potency results are presented for irradiated samples of one lot of Haemophilus b conjugate vaccine, pneumococcal polysaccharide type 6B and typhoid vi polysaccharide vaccine. The samples were irradiated (25 kGy) by gamma rays, electron beams and X-rays. IgG and IgM antibody response in mice test results (ELISA) are given for the Hib conjugate vaccine irradiated at 0 deg. C or frozen in liquid nitrogen

  5. Evaluation of some selected vaccines and other biological products irradiated by gamma rays, electron beams and X-rays

    Energy Technology Data Exchange (ETDEWEB)

    May, J.C. E-mail: may@cber.fda.gov; Rey, L.; Lee, C.-J

    2002-03-01

    Molecular sizing potency results are presented for irradiated samples of one lot of Haemophilus b conjugate vaccine, pneumococcal polysaccharide type 6B and typhoid vi polysaccharide vaccine. The samples were irradiated (25 kGy) by gamma rays, electron beams and X-rays. IgG and IgM antibody response in mice test results (ELISA) are given for the Hib conjugate vaccine irradiated at 0 deg. C or frozen in liquid nitrogen.

  6. Long-term effects in mice irradiated with low-dose gamma rays at juvenile period

    International Nuclear Information System (INIS)

    The present study was aimed to obtain dose-response relationships for the excess mortality from all causes and carcinogenesis after irradiation at juvenile period with gamma rays from 137Cs. B6C3F1 female mice were irradiated at 0 or 7 days of age with doses ranging from 0.19 to 5.7 Gy, and all the mice were allowed to live out their entire life span under a specific pathogenfree condition. The excess mortality in mice irradiated with 0.19 Gy at 0 day of age was estimated to be 8.8%. Mice of 7 days of age seemed to be more sensitive to induction of lethal diseases, as the excess mortality reached 22.3% after irradiation with 0.19 Gy. Dose-response relationship for the excess mortality was well described by an equation EM(D)=1- exp(-aD), where EM(D) represents excess mortality in a group irradiated with dose D. Incidences of liver tumors, pituitary tumors, ovarian tumors and lung tumors were significantly higher than control group in mice irradiated with doses lower than 1 Gy at 0 day of age. Shape of dose-response curves for these tumors was convex upward. Dose-response relationships were analyzed using a model which includes tumorigenic activity of radiation, sterilization of potentially tumorigenic cells and competing risks. Analysis of the experimental data showed that tumorigenic activity was proportional to dose for induction of these tumors. Relative risks at 1 Gy were estimated to be 2.52, 2.79, 16.5 and 3.17 for induction of liver tumors, pituitary tumors, ovarian tumors and lung tumors, respectively. This result implies that mice of the neonatal period are highly susceptible to induction of these tumors. On the other hand, shape of dose-response curve for incidence of bone tumors was concave upward. Dose-response relationship for induction of bone tumors was fitted by a model that tumorigenic activity of gamma rays is proportional to square of dose. (author)

  7. Life shortening and carcinogenesis in mice irradiated at the perinatal period with gamma rays

    International Nuclear Information System (INIS)

    This study elucidates the life-span radiation effects in mice irradiated at the perinatal period in comparison to mice irradiated at the young adult period. B6C3F1 female mice were irradiated at 17 days of prenatal age, at 0 days of postnatal age, or as young adults at 15 weeks of age with 190, 380, or 570 rads of 137Cs gamma rays. Mice irradiated at the late fetal period showed dose-dependent life shortening of somewhat lesser magnitude than that seen after neonatal or young adult irradiation. Mice exposed at the late fetal period were highly susceptible to induction of pituitary tumors for which the latent period was the longest of all induced neoplasms. Incidence of lung tumors in mice irradiated at the late fetal period with 190 and 380 rads was higher than in controls. Malignant lymphomas of the lymphocytic type developed in excess, after a short latent period, in mice irradiated fetally with the highest dose; susceptibility of prenatally exposed mice was lower than that of early postnatally exposed mice. Liver tumors developed more frequently in mice irradiated in utero than in controls; susceptibility to induction of this type of neoplasm was highest at the neonatal period. In general, carcinogenic response of mice exposed at the late fetal period resembled that of neonatally exposed mice but was quite different from that of young adult mice. Mice exposed as young adults have no, or low, susceptibility to induction of pituitary, lung, and liver tumors; and a higher susceptibility to induction of myeloid leukemias and Harderian gland tumors. 19 refs., 4 figs., 3 tabs

  8. Immune response against bothropstoxin-I irradiated with {sup 60}Co gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, J.A.; Spencer, P.J.; Higa, O.Z.; Casare, M.S.; Campos, L.A.; Nascimento, N. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Biologia Molecular]. E-mail: janabap@gmail.com; Andrade Junior, H.F de [Sao Paulo Univ., SP (Brazil). Inst. de Medicina Tropical de Sao Paulo. Lab. de Protozoologia]. E-mail: hfandrad@usp.br

    2005-07-01

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with gamma rays, yielding toxoids with good immunogenicity. Ionizing radiation has proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-I, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were investigated by SDS-PAGE and mass spectrometry. Aiming to compare the toxicity between native and irradiated forms of the toxin, an in vitro cytotoxicity assay, using CHO cells, was performed. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin, characterized by higher molecular weight forms of the protein (aggregates and oligomers). When analyzed by mass spectrometry, the irradiated bothropstoxin appeared in several oxidized forms. The cytotoxicity assay showed that the modified toxin was 5 folds less toxic than its native counterpart. Irradiated toxins were immunogenic and the antibodies elicited by them were able to recognize the native toxin in ELISA. These results indicate that irradiation of toxic proteins can promote significant modifications in their structures, but still retain many of the original immunological properties. (author)

  9. EPR investigation of the gamma-ray-irradiated natural and tanned collagen

    International Nuclear Information System (INIS)

    Free radicals produced in natural and tanned collagen by gamma-ray irradiation within 1-15 kGy absorbed dose ranges were investigated by EPR spectroscopy. Tanned collagen was prepared using formaldehyde as well as aluminum basic salts [Al(OH)SO4] tanning processes. Both natural and formaldehyde-tanned irradiated collagen show the same kind of EPR spectrum consisting of a single broad, slightly asymmetric line. Irradiated collagen tanned by aluminum basic salts process displayed a complex EPR spectrum consisting of a superposition of broad and narrow lines. A computer simulation of this spectrum allowed to evidence the presence of seven different kinds of paramagnetic centers, including those observed in the irradiated natural collagen. Corresponding Spin Hamiltonian parameters (g-factor, hyperfine splitting constant) as well as relative concentrations of these centers were calculated. Experimentally determined relative concentrations display a positive correlation with the absorbed dose described by a linear-type dependence. After three weeks of storage at room temperature, the concentration of some centers diminished by about 50%. The possible nature of these centers is discussed in connection with the local structure of the tanned collagen

  10. EPR investigation of the gamma-ray irradiated natural and tanned collagen.

    Science.gov (United States)

    Duliu, O G; Epuras, M; Trandafir, V

    2001-06-01

    Free radicals produced in natural and tanned collagen by gamma-ray irradiation within 1-15 kGy absorbed dose ranges were investigated by EPR spectroscopy. Tanned collagen was prepared using formaldehyde as well as aluminum basic salts [Al(OH)SO4] tanning processes. Both natural and formaldehyde-tanned irradiated collagen show the same kind of EPR spectrum consisting of a single broad, slightly asymmetric line. Irradiated collagen tanned by aluminum basic salts process displayed a complex EPR spectrum consisting of a superposition of broad and narrow lines. A computer simulation of this spectrum allowed to evidence the presence of seven different kinds of paramagnetic centers, including those observed in the irradiated natural collagen. Corresponding Spin Hamiltonian parameters (g-factor, hyperfine splitting constant) as well as relative concentrations of these centers were calculated. Experimentally determined relative concentrations display a positive correlation with the absorbed dose described by a linear-type dependence. After three weeks of storage at room temperature, the concentration of some centers diminished by about 50%. The possible nature of these centers is discussed in connection with the local structure of the tanned collagen. PMID:11300401

  11. EPR investigation of the gamma-ray-irradiated natural and tanned collagen

    Energy Technology Data Exchange (ETDEWEB)

    Duliu, O.G. E-mail: odlu@scut.fizica.unibuc.ro; Epuras, M.; Trandafir, V

    2001-06-01

    Free radicals produced in natural and tanned collagen by gamma-ray irradiation within 1-15 kGy absorbed dose ranges were investigated by EPR spectroscopy. Tanned collagen was prepared using formaldehyde as well as aluminum basic salts [Al(OH)SO{sub 4}] tanning processes. Both natural and formaldehyde-tanned irradiated collagen show the same kind of EPR spectrum consisting of a single broad, slightly asymmetric line. Irradiated collagen tanned by aluminum basic salts process displayed a complex EPR spectrum consisting of a superposition of broad and narrow lines. A computer simulation of this spectrum allowed to evidence the presence of seven different kinds of paramagnetic centers, including those observed in the irradiated natural collagen. Corresponding Spin Hamiltonian parameters (g-factor, hyperfine splitting constant) as well as relative concentrations of these centers were calculated. Experimentally determined relative concentrations display a positive correlation with the absorbed dose described by a linear-type dependence. After three weeks of storage at room temperature, the concentration of some centers diminished by about 50%. The possible nature of these centers is discussed in connection with the local structure of the tanned collagen.

  12. Methodology of in vitro gamma rays irradiations from Lonicera species; mutant description and biochemical characterization

    International Nuclear Information System (INIS)

    Microcuttings from five species of honeysuckle were irradiated in Petri dishes at the time of subculturing. The criterion of bud survival was defined as the percentage of buds providing shoots longer than 10 mm, after four months of post-irradiation culture. Cultivar survival was investigated after irradiation with a range of gamma rays from 10 to 60 Gy. A methodology of mutants isolation was developed to increase the chance for a mutation induced in one cell to give rise to a mutated sector in the regenerated plant. Among 200 regenerated plants from irradiation tests on Lonicera nitida 'Magrn', nine phenotypically obvious mutants were observed. They differ in leaf morphology, growth habit and vigour, and for chlorophyllian deficiencies. No difference between the control and the mutants was found in peroxidase, malate deshydrogenase (MDH) and glutamate oxaloacetate tranferase (GOT) zymograms. Only one very slender mutant has been characterized by the lack of a 52 kD band on the banding pattern of denaturated soluble proteins. (author)

  13. Rhizobium sp. effects, irradiated with ultraviolet and gamma rays, on nodulation of P. vulgaris (L.) bean

    International Nuclear Information System (INIS)

    Indigenous isolates of Rhizobium sp. from the root nodules of bean were selected. There of these isolates and a R. leguminosarum biovar phaseoli (SEMIA 4064) strain, used as a reference, were irradiated with ultraviolet (UV) light and gamma-Rays (?-R). The relations between survival and fluence of UV, and survival and absorbed dose of ?-R were linear for the strain of reference. The D37 values, for this rhizobial strain were 43 j.m-2 for the UV-treatment, and 32 Gy for the ?-rays treatment. Through a greenhouse experiment the irradiated isolates were inoculated on bean seedlings (P. vulgaris L, Variety IPA-8), in an attempt to evaluate sensitivity of the host-plants and possible effects on their nodulation. Significant differences were observed only for root dry matter yield. For all the other evaluated parameters variance was of such magnitude that it was not possible to detect significance of the effects. The isolates tested showed difference in responses to nodulation, due to the effects of irradiations. The host plant (IPA-8) seemed to be sensitive to the possible modifications in the irradiated isolates. (author). 10 refs, 6 figs, 1 tab

  14. Magnetic separation of amino acids by gold/iron-oxide composite nanoparticles synthesized by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Amounts of amino acids adsorbed onto the Au/?-Fe2O3 composite nanoparticles synthesized by gamma-ray irradiation were measured using magnetic separation technique. Cystine and methionine, which are sulfur-containing amino acids, connected to Au by a Au-S bond could be selectively picked up by a magnet

  15. Diversity analysis of mangosteen (Garcinia mangostana irradiated by gamma-ray based on morphological and anatomical characteristics

    Directory of Open Access Journals (Sweden)

    MUH RAHMAD SUHARTANTO

    2010-01-01

    Full Text Available Widiastuti A, Sobir, Suhartanto MR. 2010. Diversity analysis of mangosteen (Garcinia mangostana L. irradiated by gamma-ray based on morphological and anatomical characteristics. Nusantara Bioscience 2: 23-33. The aim of this research was to increase genetic variability of mangosteen (Garcinia mangostana L. irradiated by gamma rays dosage of 0 Gy, 20 Gy, 25 Gy, 30 Gy,35 Gy and 40 Gy. Plant materials used were seeds collected from Cegal Sub-village, Karacak Village, Leuwiliang Sub-district, Bogor District, West Java. Data was generated from morphological and anatomical characteristics. The result indicated that increasing of gamma ray dosage had inhibited ability of seed to growth, which needed longer time and decreased seed viability. Morphologically, it also decreased plant heigh, stem diameter, leaf seizure, and amount of leaf. Anatomically, stomatal density had positive correlation with plant height by correlation was 90% and 74%. Gamma rays irradiation successfully increase morphological variability until 30%. Seed creavage after irradiation increased variability and survival rate of mangosteen.

  16. The destructive degradation of some organic textile dye compounds using gamma ray irradiation

    International Nuclear Information System (INIS)

    The destructive degradation of 8 coloured reactive and direct dye compounds currently used in the textile industry has been investigated. These dyes are: Levafix Blue ERA (LB), Levafix Brilliant Red E4BA (LBR), Levafix Brilliant Yellow EGA (LBY), Drimarene Scarlet F3G (DS), Drimarene Brilliant Green X3G (DBG), Fast Yellow RL (FY), Fast Violet 2RL (FV) and Fast Orange 3R (FO). The process of degradation of the respective dye has been followed spectrophotometrically at the characteristic lmax. The variation of the colour intensity of aerated aqueous solution of the investigated dyes has been measured as a function of gamma irradiation dose. In all cases, the amplitude of the absorption bands of the dye compound was found to decrease with the increase of the gamma dose. Irradiation was carried out for actual waste and distilled water. By comparing the heights of the absorption maxima in both the visible and ultraviolet ranges, it was found that complete decolouration is attained at lower doses than that needed for the process of degradation of the dye. The kinetics of the degradation process has been traced and the kinetic constant, k1, was calculated and found to be concentration dependent indicating a first order reaction in all cases. The radiation-chemical yield (G-value) as a measure of the efficiency of gamma ray to degrade the respective dye was calculated for all dye compounds and it was found that the G-value in all cases increases exponentially for low radiation doses and changes linearly for high radiation doses. Also the K* value (the efficiency coefficient of dye radiolysis) was calculated and compared for the different dye compounds e.g. for FO, FY and FV dyes, the K* values were found to range from 5.5x109 to 1.92x10-7 molL-1'cm-1. In addition to the study of a single dye compound in solution, mixtures of different dyes (3 dyes) were also subjected to g-ray irradiation simulating more closely actual waste effluents. Also the effect of some other chemicals used in the textile industry such as H2O2 and NaOCI on the degradation process was investigated. The specific bimolecular rate constants of the reaction of dyes with the hydroxyl radical (OH) were determined by studying the effect of ethanol concentration on G-value using competition kinetics. The effect of pH, NaOCI and H2O2 on the degradation process was studied. In addition to the main objective of the use of gamma rays to achieve the destruction of the dye compounds, the eco-toxicity of the dyes and their irradiation products was assessed using some invertebrate animals (snails) for the three FO, FY and FV dyes. The FV dye and its degradation products were found to be toxic (results of hemocyte count, hemagglutination titter, total protein content and accumulation levels) and should be completely degraded and removed from the wastewater streams using high irradiation doses. Also, and for the purpose of comparison, the sorption of the FV, FY and FO dyes on conventional sorbents such as charcoal was tested, gamma ray irradiation, as compared with conventional sorption techniques, was found to be very rapid and the removal of organic pollutants from wastewaters can be achieved nearly instantaneously. It appears that, for the complete destruction and full removal of organic pollutants from waste effluents, the sequential adsorption using chemical techniques followed by gamma irradiation treatment may prove to be more effective and advantageous. (author)

  17. Determination of optimum dose of gamma rays for regeneration of irradiated rice callus. Screening for salt tolerance

    International Nuclear Information System (INIS)

    Determination of optimum dose of gamma rays for regeneration of irradiated rice callus. Screening for salt tolerance. Callus were gamma irradiated with acute doses between 10 and 60 Gy, with fractionated doses at 2 x 10 Gy, 2 x 20 Gy and 2 x 30 Gy of one-hour intervals for recovery. Immediately after irradiation, callus were placed on differentation medium supplemented with 37.5% sea water. The highest shoots regeneration (55.3%) was obtained after 20 Gy treatment. The lowest shoots regeneration (24%) was obtained after 60 Gy. Fertility of plants was not parallel with total shoots formation. Plants obtained from irradiated callus with fractioned doses had high fertility. Fractioned dose of 2 x 30 Gy produced plants with 74% fertility. Acute dose at 60 Gy produced sterile plants. Based on the quotient 'number of shoots or fertilities per number of irradiated units', the calculated value for the 10 Gy irradiation was put at 1.00. The relative effectivity of gamma-rays for shoots formation at 0, 10, 20, 30, 40, 50, 60, 2 x 10, 2, 20, 2 x 30 Gy was 0.61, 1.00, 1.01, 0.70, 0.63, 0.49, 0.44, 0.73, 0.70 and 0.46, respectively. The relative effectivity of gamma-rays for fertility at 0, 10, 20, 30, 40, 50, 60, 2 x 10, 2 x 20, and 2 x 30 Gy was 0.40, 1.00, 0.75, 0.59, 0.40, 0, 1.43, 1.45 and 1.35 respectively. Considering to the highest relative effectivity of gamma-rays for shoots formation and plant fertilities, it was concluded that optimum dose of gamma-rays to induce salt tolerance was fractioned dose of 2 x 10 Gy. (author). 10 refs.; 1 figs

  18. Study of irradiated bothropstoxin-1 with {sup 60}Co gamma rays: immune system behavior

    Energy Technology Data Exchange (ETDEWEB)

    Caproni, P.; Baptista, J.A.; Almeida, T.L. de; Nascimento, N. [Nuclear and Energy Research Institute (IPEN/CNEN-SP), SP (Brazil). Biotechnology Center; Passos, L.A.C. [State University of Campinas (UNICAMP), SP (Brazil). Lab. of Genetics and Embryo Cryopreservation

    2009-07-01

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response. (author)

  19. Study of irradiated bothropstoxin-1 with60Co gamma rays: immune system behavior

    Scientific Electronic Library Online (English)

    P, Caproni; JA, Baptista; TL de, Almeida; LAC, Passos; N, Nascimento.

    Full Text Available Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modifi [...] ed antigens with lower toxicity and preserved or improved immunogenicity can be very useful. Ionizing radiation has already been proven to be a powerful tool to attenuate snake venom toxicity without affecting, and even increasing, their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we investigated the immunological behavior of bothropstoxin-1, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were analyzed by SDS-PAGE. Isogenic mice were immunized with either the native or the irradiated toxin. The circulating antibodies were isotyped and titrated by ELISA. According to our data, irradiation promoted structural modifications in the toxin characterized by higher molecular weight forms of proteins (aggregates and oligomers). The results also indicated that irradiated toxins were immunogenic and antibodies elicited by them were able to recognize the native toxin in ELISA. These findings suggest that irradiation of toxic proteins can promote significant modifications in their structures; however they still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that irradiated proteins induce higher titers of IgG2a and IgG2b, suggesting that Th1 cells are predominantly involved in the immune response.

  20. Effects of acid/alkaline pretreatment and gamma-ray irradiation on extracellular polymeric substances from sewage sludge

    International Nuclear Information System (INIS)

    In order to investigate the mechanism of extracellular polymeric substances (EPS) influencing sludge characteristics, variations of extractable EPS from municipal sewage sludge by acid/alkaline pretreatment and gamma-ray irradiation were studied. The changes in constituents of EPS were analyzed by UV–vis spectra and SEM images. The effects of alkaline pretreatment and gamma-ray irradiation on the functional groups in EPS were investigated by Fourier transform infrared (FTIR) spectrometer. Results showed that the extractable EPS increased clearly with increasing irradiation dose from 0 to 15 kGy. UV–vis spectra indicated that a new absorption band from 240 nm to 300 nm existed in all irradiated samples, apart from acid condition. The results of FTIR spectroscopic analysis indicated that, irradiation influenced major functional groups in EPS, such as protein and polysaccharide, and these effects were clearer under alkaline condition. SEM images provided that after alkaline hydrolysis, gamma-ray irradiation was more effective in resulting in the sludge flocs and cells broken, compared with acid pretreatment (pH 2.50). - Highlights: • Effects of acid/alkaline pretreatment and gamma irradiation on EPS were examined. • Gamma irradiation and alkaline treatment generated remarkable synergistic effects. • The combined application could promote sludge disintegration and solubilization

  1. Behavior of the dynamic magnetic susceptibility in ybco bula ceramics irradiated with gamma rays

    International Nuclear Information System (INIS)

    Using measurements of the ac susceptibility, the behavior with the irradiation dose of YBa2Cu3O7- bulk ceramics synthesized by the classic reaction method in solid state, was studied. A Co60 gamma chamber model MPX-G-25M and a Cs137 source were employed as gamma ray sources. The behavior of the beginning temperature of the normal - superconducting state transition with the exposition dose show, independently of the incident gamma energy, a monotonous growth until reaching a threshold dose, after which, observe a fall, more abrupt in the case of the Co60. This behavior can be explained using the model that postulates the ability of the gamma radiation, in certain dose intervals, to stimulate the structural reordering in the oxygen sublattice. When the irradiation process takes place in the Co60 gamma chamber, the behavior of the superconducting volume fraction of the sample characterizes by the initial sharp fall with the dose, followed with an attenuation of the decrement. In the case of Cs137 irradiation, the behavior of the superconducting volume fraction is similar to the behavior of the Ton with the dose

  2. Investigation of effects of gamma ray irradiation on pyrolysis properties of glove-box panel materials

    International Nuclear Information System (INIS)

    The glove box (GB) is a device with some plastic components and is used for the containment of radioactive materials. In a MOX fuel fabrication facility, MOX is also handled in the GB. Since the plastic panel, which has the largest area in the GB, is used over a long period, it is exposed to a high dose of MOX continuously. In this study, to confirm whether the containment capability of GB can be maintained even under external thermal stress, the effects of gamma ray irradiation with 60Co on the pyrolysis properties of the common panel materials were investigated by TG-DTA. As a result, polymethylmethacrylate showed a large peak of the mass loss rate at about 260 degrees under the nonirradiation and air condition, but it separated into lower and higher temperature sides above 25 kGy. This effect was not observed up to 10 kGy for polymethylmethacrylate and up to 880 kGy for polycarbonate. By comparison with the estimated total dose of the GB panel irradiated in the operation period, it was found that the irradiation from MOX does not significantly affect the pyrolysis properties of the GB panel in the actual facility. (author)

  3. Meiotic chromosome behaviours in M1 generation of bread wheat irradiated by gamma-rays

    International Nuclear Information System (INIS)

    Growing plants of bread wheat (Triticum aestivum L. 2 n=6x=42, AABBDD) were subjected to acute or chronic irradiation by gamma-rays from 60Co and meiotic chromosome behaviours of PMCS in M1 generation were cytologically compared. Both acute and chronic irradiations produced different types of chromosomal aberrations at the meiotic stages. Among them, translocation type was the most frequent, followed by univalent type. A mixed type, i. e. translocation accompanying one or more univalents was often detected. Even normal type which lacked translocation and univalent included laggards and briclges without exception. Other meiotic abnormalities such as deletion, iso-chromosome and micronuclei were observed frequently in both treatments. Dose dependency of translocation frequency was not recognized in this experiment. In chronic irradiation, different chromosome numbers and meiotic behaviours were found not only among florets of a spike but also among anthers of a floret. A number of plants with aneuploid-like grass types occurred at a high frequency in M1, especially with low exposure

  4. Mutation Breeding of various spray chrysanthemum cultivars by gamma-ray irradiation

    International Nuclear Information System (INIS)

    This study was carried out to analyze mutation rate and spectrum of chrysanthemum by gamma-ray irradiation. Five flower types, 16 cultivars including 'Geumsu', 'Hwiparam', 'Ilwol', 'Magic', 'Moonlight', 'Noblewine', 'Pinky', 'Progy', 'Sangtte', 'Waterfog', 'Whitneypangpang', 'Yelloweye', 'Yellowpangpang', 'Yesmiso', 'Yesmorning', and 'Yestogether' were irradiated as 30, 50, and 70 Gy dose during 24 hours. As a result, mutation rate was identified as the highest in single type among five flower types, but there was a little difference according to cultivars. Mutation rate was increased in proportion to irradiation dose in anemone, pompon, and spider type cultivars, but there wasn't clear in single and semi-double type cultivars. Mutation spectrum was identified as the highest in the cultivar 'Noblewine'. The most sensitive cultivars to radiation were revealed as 'Noblewine' and 'Yesmorning' and the least were Moonlight', 'Waterfog', and 'Yellowpangpang'. Consequently, there was much difference in radio-sensitivity according to cultivars of chrysanthemum and flower type was correlated a little with mutation rate

  5. Study of stability of humic acids from soil and peat irradiated by gamma rays

    International Nuclear Information System (INIS)

    Humic acids samples (one deriving from a sedimentary soil and other from a peat), in aqueous media, were irradiated with gamma rays, in doses of 10, 50 and 100 kGy, in order to understand their chemical behavior after the irradiation. The material, before and after irradiation, was analyzed by Elemental Analysis, Functional Groups (carboxylic acids and phenols), UV/Vis Spectroscopy (E4/E6 ratio), IR spectroscopy, CO2 content and Gel permeation Chromatography (GPC) ). The Elemental Analysis showed the humic acid derived from a peat had a most percentage quantity of Carbon and Hydrogen than the material from a sedimentary soil. From the UV/Vis Spectroscopy, it was observed a decrease of E4/E6 ratio with an increase of the applied dose. The data from GPC are in agreement with this. The results showed that the molecular weight of the material increased by exposing it to a larger radiolitical dose. The peat material was less affected by the gamma radiation than the soil material. The carboxylic groups were responsible by radiochemical behavior of the material. (author)

  6. A high-capacity gamma-ray spectrometer facility in the NIST irradiation laboratory

    International Nuclear Information System (INIS)

    As the demand for greater throughput and shorter turnaround times for analytical work is increasing, instrumental neutron activation analysis (INAA) has come under pressure to substantially improve its performance in these areas. Of course, such improvements are expected without any loss of quality in other performance parameters, such as precision and accuracy. The National Institute of Standards and Technology (NIST) is responding to the aforementioned demands with increased utilization of short-lived ultrashort-lived nuclides and high-rate counting techniques in INAA. Part of this effort involves, in the course of the renovation of the NIST research reactor irradiation laboratories, the establishment of a newly designed gamma-ray spectrometry facility with three high-rate, high-resolution germanium detectors. The three detectors allow simultaneous counting of three samples and/or standards irradiated at the same time. The detector systems have been evaluated in a preliminary setup and are now being relocated in close proximity of the irradiation terminals to achieve short sample transfer times

  7. Evaluation of myotoxic activity of Bothropstoxin-1 irradiated with {sup 60}Co gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Mirco, Jessica; Baptista, Janaina A.; Caproni, Priscila; Yoshito, Daniele; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)], e-mail: jessica.mirco@yahoo.com.br, e-mail: janabap@gmail.com, e-mail: pricaproni@hotmail.com, e-mail: daniyoshito@uol.com.br, e-mail: nnascime@ipen.br

    2009-07-01

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules and has been proven to be a powerful tool to attenuate snake venoms toxicity without affecting their immunogenic properties. Snake venoms and their isolated toxins showed structural modifications after gamma radiation process, in aqueous solution, mainly by water radiolysis sub products. Free radical scavengers, such as NaNO{sub 3} and t-butanol, present selective effects on specific radical from water radiolysis. The NaNO{sub 3} has affinity by aqueous electron, while the t-butanol has affinity by hydroxyl radical. At the present work, we have investigated the myotoxic activity of Bothropstoxin-1 (BTHX-1), a K49 phospholipase, present in Bothrops jararacussu crude venom, before and after irradiation process, with or without scavenger substances presence. BTHX-1 was irradiated with 2 kGy of {sup 60}Co gamma rays, in aqueous solution and in the presence of oxygen. BALB/c mice were inoculated with either native or irradiated toxin, with or without scavenger substances. After 3 hours, blood samples were collected and the myotoxic activity was evaluated by LDH (lactate dehydrogenase) release. The muscular tissue damage was directly related to the LDH amounts released. Irradiated Bothropstoxin-1, with or without NaNO{sub 3} substance, caused less damage than their native counterpart. But irradiated toxin, in the presence of t-butanol, was so myotoxic as the native BTHX-1. These results indicate that irradiation of toxic proteins can promote significant modifications on their structures, but still retaining many of the original biological properties of their native counterparts. Additionally, some scavengers substances can change these gamma radiation effects. (author)

  8. Evaluation of myotoxic activity of Bothropstoxin-1 irradiated with 60Co gamma rays

    International Nuclear Information System (INIS)

    Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules and has been proven to be a powerful tool to attenuate snake venoms toxicity without affecting their immunogenic properties. Snake venoms and their isolated toxins showed structural modifications after gamma radiation process, in aqueous solution, mainly by water radiolysis sub products. Free radical scavengers, such as NaNO3 and t-butanol, present selective effects on specific radical from water radiolysis. The NaNO3 has affinity by aqueous electron, while the t-butanol has affinity by hydroxyl radical. At the present work, we have investigated the myotoxic activity of Bothropstoxin-1 (BTHX-1), a K49 phospholipase, present in Bothrops jararacussu crude venom, before and after irradiation process, with or without scavenger substances presence. BTHX-1 was irradiated with 2 kGy of 60Co gamma rays, in aqueous solution and in the presence of oxygen. BALB/c mice were inoculated with either native or irradiated toxin, with or without scavenger substances. After 3 hours, blood samples were collected and the myotoxic activity was evaluated by LDH (lactate dehydrogenase) release. The muscular tissue damage was directly related to the LDH amounts released. Irradiated Bothropstoxin-1, with or without NaNO3 substance, caused less damage than their native counterpart. But irradiated toxin, in the presence of t-butanol, was so myotoxic as the native BTHX-1. These results indicate that irradiation of toxic proteins can promote significant modifications on their structures, but still retaining many of the original biological properties of their native counterparts. Additionally, some scavengers substances can change these gamma radiation effects. (author)

  9. Study on the gamma-ray irradiation behavior of mesoporous silica adsorbents functionalized with phosphine oxide and phosphonic acid ligands

    International Nuclear Information System (INIS)

    The resistance of mesoporous silica adsorbents bearing phosphine oxide (SBA-P(O)Pr2) and phosphonic acid (SBA-P(O)(OH)2) to gamma-ray irradiation (in air and 2 mol/ L HNO3 solution) was systematically evaluated. The change in the composition, structure and (U(VI)) adsorption ability of the adsorbents was examined. Both the organophosphorus ligands functionalized adsorbents exhibited remarkable durability under gamma-ray irradiation up to a total dose of 5 x 105 Gy. The mesoporous silica framework and the two classes of organophosphorus ligands were well-reserved without irradiation damage. Moreover, after irradiation, the adsorbents still maintained an effective adsorption of U(VI) in high acidic or pH range solutions. (author)

  10. Dose Distribution Calculation Using MCNPX Code in the Gamma-ray Irradiation Cell

    International Nuclear Information System (INIS)

    60Co-gamma irradiators have long been used for foods sterilization, plant mutation and development of radio-protective agents, radio-sensitizers and other purposes. The Applied Radiological Science Research Institute of Cheju National University has a multipurpose gamma irradiation facility loaded with a MDS Nordin standard 60Co source (C188), of which the initial activity was 400 TBq (10,800 Ci) on February 19, 2004. This panoramic gamma irradiator is designed to irradiate in all directions various samples such as plants, cultured cells and mice to administer given radiation doses. In order to give accurate doses to irradiation samples, appropriate methods of evaluating, both by calculation and measurement, the radiation doses delivered to the samples should be set up. Computational models have been developed to evaluate the radiation dose distributions inside the irradiation chamber and the radiation doses delivered to typical biolological samples which are frequently irradiated in the facility. The computational models are based on using the MCNPX code. The horizontal and vertical dose distributions has been calculated inside the irradiation chamber and compared the calculated results with measured data obtained with radiation dosimeters to verify the computational models. The radiation dosimeters employed are a Famer's type ion chamber and MOSFET dosimeters. Radiation doses were calculated by computational models, which were delivered to cultured cell samples contained in test tubes and to a mouse fixed in a irradiation cage, and compared the calculated results with the measured data. The computation models are also tested to see if they can accurately simulate the case where a thick lead shield is placed between the source and detector. Three tally options of the MCNPX code, F4, F5 and F6, are alternately used to see which option produces optimum results. The computation models are also used to calculate gamma ray energy spectra of a BGO scintillator at several points of the irradiation chamber. It is found that the calculated horizontal dose distribution agrees with the measured data within 5% deviation. The calculated vertical dose distribution generally agrees well with the measured data, but there exist large discrepancies between the calculated and measured data at some points. It is found that these discrepancies have originated from the MOSFET dosimeters used rather than from the computation models. The computed results show a smooth pattern of the dose distribution while the measured data show a very irregular pattern which seems very unnatural. It is deemed that the some of the dosimeters have been inaccurately calibrated. The calculated doses behind a thick lead shield agree with the data measured with ion chamber within 4% deviation. The calculated absorbed doses delivered to the biological samples agrees with the measured data within 5% deviation. The effect of different tally options dose not show a consistent pattern. In some points one tally option agrees better with the measured data while in other points another tally option agrees better. The gamma ray energy spectra for a BGO scintillator calculated with the MCNPX computation model show the full energy peaks more prominent as the detector is closer to the source. The heights of full energy peaks become lower behind the lead shield due to the interference of the scattered gammas

  11. Analysis of cell kinetics after gamma ray irradiation using anti-BrdU monoclonal antibody

    International Nuclear Information System (INIS)

    The cell cycle was analyzed using anti-BrdU monoclonal antibody, and changes in cell kinetics after gamma ray irradiation as evaluated by this BrdU-PI double staining were compared with those evaluated by the DNA histogram method based on PI staining. The effect of irradiation on the cell kinetics has been studied according primarily to the number of G2 blocked cells. By the present BrdU method, rapid transition of the G1-S phase was observed within 2 hours of irradiation, and then G1 block was observed. Cells in the S phase progressed to the G2 + M cells returned to the G1 phase after 18 or more hours. These initial G1 blocked cells induced by irradiation were confirmed for the fist time by the present BrdU-PI double staining. By the conventional method based on the DNA histogram, accurate determination of S cell fraction was difficult due to overlapping of the DNA contents of G1 cells and early S cells and those of late S cells and G2 cells. On the other hand, BrdU-PI double staining allowed direct differentiation of G1, S, and G2 + M cells, especially between G1-S and S-G2 + M cells. The analysis of cell kinetics using BrdU is advantageous over the conventional autoradiographic methods in that it allowed more rapid assay with very high sensitivity. In addition, BrdU is alrady used clinically as an enhancement agent in radiation therapy for cancer. The present method is considered to be indispensable for evaluation of the percentage of S cells in the tumor tissue and analysis of cell kinetics after irradiation and chemotherapy against cancer. (author)

  12. Dose calculation method with 60-cobalt gamma rays in total body irradiation

    CERN Document Server

    Scaff, L A M

    2001-01-01

    Physical factors associated to total body irradiation using sup 6 sup 0 Co gamma rays beams, were studied in order to develop a calculation method of the dose distribution that could be reproduced in any radiotherapy center with good precision. The method is based on considering total body irradiation as a large and irregular field with heterogeneities. To calculate doses, or doses rates, of each area of interest (head, thorax, thigh, etc.), scattered radiation is determined. It was observed that if dismagnified fields were considered to calculate the scattered radiation, the resulting values could be applied on a projection to the real size to obtain the values for dose rate calculations. In a parallel work it was determined the variation of the dose rate in the air, for the distance of treatment, and for points out of the central axis. This confirm that the use of the inverse square law is not valid. An attenuation curve for a broad beam was also determined in order to allow the use of absorbers. In this wo...

  13. Studying the Dosimetric Properties of GAMMA Rays Irradiated Chlorophyll Polyvinyl Alcohol

    International Nuclear Information System (INIS)

    Polyvinyl alcohol/chitosan/chlorophyll (PVA/Chit/Chl) films with about 2 mm thickness were prepared using gamma irradiation technique. The chlorophyll samples were extracted from fresh spinach leaves and PVA/Chit/Chl films were irradiated with gamma rays to study radiation-induced radicals as a dosimetric material using electron spin resonance (ESR), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The ESR dose response and spectrophotometric analysis showed that chitosan decrease the response. The chlorophyll spectrum was characterized by dosimetric signal of spectroscopic splitting factor g = 2.0058. This signal is ascribed to the charge transfer complex of the molecular oxygen and the chlorophyll aggregate with strong pi-pi-interactions (aromatic interactions). The dose response was studied in the range from 1 to 500 kGy. Radical formation efficiency (G value) was obtained to be 0.15 0.03. The dose conversion factors for chlorophyll in water and air were calculated to be 0.971 D water and 1.080 D air

  14. ESR study of free radicals in UHMW-PE fiber irradiated by gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yanning [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, PO Box 800-204, Shanghai 201800 (China); College of Chemistry, Jilin Normal University, Jilin 136000 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Wang Mouhua [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, PO Box 800-204, Shanghai 201800 (China); Tang Zhongfeng [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, PO Box 800-204, Shanghai 201800 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Wu Guozhong, E-mail: wuguozhong@sinap.ac.c [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, PO Box 800-204, Shanghai 201800 (China)

    2010-04-15

    ESR spectra of the trapped radicals in an ultra-high molecular weight polyethylene (UHMW-PE) fiber irradiated by gamma rays showed well-resolved hyperfine splitting at room temperature since the c-axis of the crystallites is aligned with the fiber direction and the radicals are trapped in crystallites. The alkyl radical (-CH{sub 2}-{sup c}entre dotCH-CH{sub 2}-) was the major product after irradiation in vacuum and in air at room temperature. Some of the alkyl radicals converted to allyl radicals (-CH{sub 2}-{sup c}entre dotCH-CH=CH-) and polyenyl radicals (-CH{sub 2}-{sup c}entre dotCH-(CH=CH){sub n}-CH{sub 2}-) during storage in vacuum. Upon storage in air atmosphere, the alkyl radicals decayed by reaction with oxygen. Of particular interest is the very slow decay rate of the alkyl radical trapped in UHMW-PE fiber, the half-life is 26 days in vacuum, and 13 days in air at room temperature, which is about 1/30 and 1/100 of that reported for high density polyethylene (HDPE), respectively. The extremely long lifetime of the alkyl radical is supposed to be caused by the large size of crystallites in UHMW-PE fiber. The rate of radical decay was accelerated by annealing at elevated temperature.

  15. Perna perna (LINNAEUS, 1758) mussels irradiated by {sup 60}CO gamma rays cytotoxicity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Martini, Gisela A.; Pusceddu, Fabio H.; Rogero, Sizue O.; Rogero, Jose Roberto, E-mail: gisela.martini@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The aim of the present work was the study of ionizing radiation effects on aquatic biota regarding the location of nuclear facilities nearby coastal areas assuming the risk of leaks and nuclear accidents. Bivalve mollusks have been widely used in the monitoring of aquatic environment studies mainly for their sessile habit and pollutants bioconcentration ability. So marine mussel Perna perna (Bivalvia: Mytilidae) was used as organism test in this study. The study of radioactive toxicity was performed by cytotoxicity test exposing the organisms to 11Gy gamma radiation dose. After radiation the neutral red retention assay evaluated the lysosomal membrane integrity in the mussel hemocytes. 50% lethal dose assay (LD50) of gamma radiation on Perna perna mussels was carried out by exposure the organisms to {sup 60}Co gamma rays at doses ranging from 0 to 3000 Gy. The result of gamma radiation LD50 for these mussels was 1068 Gy and the neutral red retention time of irradiated organisms was about 47% lower than the control, non irradiated organisms. With the obtained results is expected to contribute in the study to identify the range of ionizing radiation doses which can cause toxic effects in marine invertebrates. (author)

  16. Perna perna (LINNAEUS, 1758) mussels irradiated by 60CO gamma rays cytotoxicity evaluation

    International Nuclear Information System (INIS)

    The aim of the present work was the study of ionizing radiation effects on aquatic biota regarding the location of nuclear facilities nearby coastal areas assuming the risk of leaks and nuclear accidents. Bivalve mollusks have been widely used in the monitoring of aquatic environment studies mainly for their sessile habit and pollutants bioconcentration ability. So marine mussel Perna perna (Bivalvia: Mytilidae) was used as organism test in this study. The study of radioactive toxicity was performed by cytotoxicity test exposing the organisms to 11Gy gamma radiation dose. After radiation the neutral red retention assay evaluated the lysosomal membrane integrity in the mussel hemocytes. 50% lethal dose assay (LD50) of gamma radiation on Perna perna mussels was carried out by exposure the organisms to 60Co gamma rays at doses ranging from 0 to 3000 Gy. The result of gamma radiation LD50 for these mussels was 1068 Gy and the neutral red retention time of irradiated organisms was about 47% lower than the control, non irradiated organisms. With the obtained results is expected to contribute in the study to identify the range of ionizing radiation doses which can cause toxic effects in marine invertebrates. (author)

  17. Manufacturing of a wood-plastic combination by irradiation of gamma-rays

    International Nuclear Information System (INIS)

    The studies on the wood-plastic combination (WPC) were carried out by gamma-ray irradiation. After impregnation of dry woods (Chamaecy Paris Obtusa ENDL., Cryptomeria japonica D.DON, Fagus renata BLUME., Acer mono MAXIM. and Shorea) with methyl methacrylate, emulsion of methyl methacrylate or unsaturated polyester (selfextinguishing type), the monomer in wood was polymerized by the irradiation. The percent of polymerization various monomers decreased remarkably in the presence of oxygen. WPC obtained were studied on the swelling, thermal and mechanical characteristics. The percent of welling in water of WPC impregnated with methyl methacrylate emulsion is less than that of WPC impregnated with methyl methacrylate (pure). WPC-polyester was shown to be non-inflammable. The pyrolysis gas of the WPC-methyl methcrylate and WPC-polyester is investigated, using a pyrolysis gas chromatography instrument. At the pyrolysis temperature of 3000C the decomposition gas prove to be mainly originated from the polymer in the WPC. The bending and compression strength of the WPC increased together with the weight of polymer in the wood. (auth.)

  18. Filler for gamma ray-irradiated EPR and ultralow frequency dielectric characteristics

    International Nuclear Information System (INIS)

    For the purpose of diagnosing the radiation deterioration of the electric cables and wires for nuclear power stations, the authors have studied on the ultralow frequency dielectric characteristics of the EPR in which hard clay was mixed as the filler. As the results, it was found that the distribution parameter was nearly constant independent of the amount of the filler, and the change of the relative dielectric constant increased monotonously with the amount of the filler. In order to explain the complicated change of the mean relaxation time due to the amount of filler, the authors examined it by using the interface polarization model for the region of the mixing of small amount and the equivalent two-layer interface model for the region of the mixing of large amount. Subsequently, the dielectric characteristics of the gamma ray-irradiated samples were examined, and those are reported in this paper. The samples irradiated with a Co-60 source, the ultralow frequency dielectric characteristics, the results of heat treatment, the analysis using the interface polarization model with an ellipsoid of revolution and so on are described. (K.I.)

  19. Electrical insulating performances of SiC materials under gamma-ray irradiation

    International Nuclear Information System (INIS)

    For evaluation of electrical insulating performances of SiC materials in radiation and high temperature environments, electrical conductivities of single crystal and sintered SiC materials were measured under gamma-ray irradiations at temperatures of up to ∼450degC. The radiation induced conductivities (RICs) evaluated for single crystal SiC plates were 2.8 x 10-8 – 1.3 x 10-7 S/m under the irradiations of 2.3 Gy/s at room temperature. The RICs in the sintered SiC plates were almost below measurable level due to their high inherent conductivities. The magnitudes of the RICs did not increase significantly with temperature. Extrapolation from the present data indicates that the maximum magnitude of RIC in SiC materials would be the order of 10-4 S/m for a dose rate of several kGy/s at a first wall of a fusion reactor. The magnitude is adequately lower than the allowable electrical conductivities in the SiC flow channel inserts (FCIs) for the dual-cooled lithium lead (DCLL) blanket design. (author)

  20. Immobilization of Simulated Transuranic Liquid Waste on Epoxy Acrylate Polymer by Gamma Ray Irradiation Method

    International Nuclear Information System (INIS)

    Immobilization of transuranic (TRU) liquid waste of spent solvent from the reprocessing of Light Water Reactor (LWR) spent fuel was done using epoxy acrylate polymer. Epoxy acrylate was mixed with tripropylene glycol diacrylate with a ratio of 4/1 by weight, and added with simulated TRU waste. The variations of waste concentrations in the mixture were 0, 10, 20, 30 and 40 weight %. Samples were irradiated in glass tubes of 14 mm diameter and 125 mm long by gamma ray from a Co-60 source of 70.6 kCi with dose of 7.5, 10.0 and 12.k kGy respectively, at a dose rate of 5 kGy/hour. These immobilization products were tested for their leaching rate in Soxhlet apparatus at 100oC for 6 hours and their compression strength by Paul Weber compressive strength apparaturs. The higher the radiation dose, the higher the compression strength and leaching rate. The higher the waste loading, the higher the compression strength and the leaching rate. Epoxy arcylate immobilization products with 20-40 weight % waste made under irradiation doses of 7.5 and 10.0 kGy can be considered for radiation durability testing. (author). 6 refs., 3 tabs., 2 figs

  1. EPR study of the formation of radicals in PP with antioxidants irradiated with gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P. [Instituto Venezolano de Investigaciones Cientificas, Centro de Fisica, Carretera Panamericana Km. 11, Caracas 1020-A (Venezuela)], E-mail: silva@ivic.ve; Albano, C. [Instituto Venezolano de Investigaciones Cientificas, Centro de Quimica, Universidad Central de Venezuela, Facultad de Ingenieria (Venezuela); Perera, R. [Departamento de Mecanica, Universidad Simon Bolivar (Venezuela)

    2007-12-15

    The behavior of different compounds of polypropylene (PP) with stabilizers such as buthyl-hydroxy-toluene (BHT), Chimassorb 944 (Hals) (CHIM), and a copolymer of styrene-butadiene-styrene (SBS) was studied using electron paramagnetic resonance (EPR). A characteristic spectra for pure PP irradiated in air was obtained for all the samples just after being irradiated [M. Dole, The Radiation Chemistry of Macromolecules, Vol. 2, Academic Press, 1973]. A change in the lineshape of the spectra from a pure PP's EPR signal to that of nitroxyl radical as a function of time was observed. The total free radical concentration (TFRC) decayed until approximately 800 h in the PP-HALS and until around 2000 h in all other cases, when the TFRC began to increase in all the cases, except in that of PP-BHT. In this last case, the EPR signal was not detectable after 4000 h. The BHT and the SBS diluted the free radical concentrations, being them smaller when they are present. The behavior observed in all the samples is consistent with the formation of nitroxyl radicals by gamma rays.

  2. Effects of follicle stimulationg hormone on {gamma}-ray irradiated immature mouse ovarian follicles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Lee, Chang Joo; Lee, Young Keun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Song, Kang Won; Yoon, Yong Dal [Hanyang Univ., Seoul (Korea, Republic of)

    1998-06-01

    To assess the radioprotective effects of Follicle Stimulating Hormone (FSH) on ovarian follicles, 3 week-old female mice were irradiated with 8.33 Gy of {gamma}-ray (group R) and followed by 5 IU ip-injection of FSH (group RF). For control groups, 5 IU of saline (group C) or 5 IU of FSH (group F) was ip-injected. Ovaries were collected 0h, 6h, 12h, 1d, 2d, 4d, and 8d after irradiation or saline/FSH injection, and followed by fixation in neutral buffered formalin for routine histochemistry. Immunohistochemistry was used to assess the status of follicles and DNA fragmentation was analyzed by agarose gel electrophoresis for total DNA. Staining specific for apoptotic follicles showed high intensity at 6h and 12h in group R and RF. On the other hand, staining specific for proliferating follicles showed noticeably high intensity at 8d in group R and RF. DNA fragmentation of 185bp increased with time in all experimental groups. Especially 370bp appeared at 6h in group R, then disappeared after 1d. In case of group RF, it appeared at 12h and disappeared after 1d. From the above results, the irradiated antral follicles become completely disappeared from 4d to 8d, and then new follicles started to grow again at 8d. FSH had delaying or suppressing effects on follicular atresia after irradiation. In addition, it became clear that radiation-induced follicular atresia was mediated by granulosa cell apoptosis.

  3. Obtainment of a drug delivery system from PVAL irradiated by gamma rays

    International Nuclear Information System (INIS)

    The poly(vinyl alcohol) (PVAL) is a polymer used as biomaterial. In this work the PVAL was irradiated by gamma rays from 60Co source with doses up to 200 kGy. The PVAL was used to prepare hydrogels that may be used as a drug delivery system in ocular implant, for pair PVAL/dihidroxypropoximethyl guanine, where the last one is used for treatment of people with retinite caused by cytomegalovirus. The dose effect was studied on various properties of PVAL: the molecular weight by viscosity, the crosslink degree (Gcross-link= 8,5) calculated from gel dose (Dg = 7,8 kGy), the average molecular weight between crosslinks, crosslinking density, tensile strength at break and the degree of crystallinity by differential scanning calorimetry. Formation and thermal decay radical were studied by electronic paramagnetic resonance. It was used the technique of superposition and subtraction of spectra obtained at various temperatures (77 K, 125 K, 170 K, 230 K and 280 K). The radicals formed were identified on irradiated PVAL on vacuum and air at 77K with 20 kGy. The thermal decay showed that air caused polymer oxidation, even after end the irradiation, because the ·OH, RO· and ROO · radicals were formed. The dose effect on molecular structure of PVAL was studied by transmission spectroscopy on infrared region and nuclear magnetic resonance of proton. The PVAL structural alteration was not observed up to 200kGy, although crosslink occurred on PVAL. The PVAL hydrogel formation occurred at doses upper 70 kGy and drug controlled released occurred with zero order kinetic on PVAL hydrogel irradiated with 80 kGy. (author)

  4. Study on gamma-ray irradiation effects on corrosion resistance of canister material under the simulated disposal conditions

    International Nuclear Information System (INIS)

    The effects of gamma-ray irradiation on corrosion resistance have been studied about austenitic stainless steel as one of the candidate alloys for high-level radioactive waste canisters. The double U-bend specimens were used for the purpose of stress corrosion cracking (SCC) test on Type 304 ss and Type 309S ss. Sensitized Type 304 ss and Type 309S ss specimens were encapsuled respectively in capsules with a cubic granite and simulated groundwater. Test specimens were also encapsuled in a capsule with only humid bentonite in order to simulate the disposal environments. Capsules were irradiated with 137Cs source at WASTEF and with spent fuel in JMTR. The results showed that sensitized Type 304 ss have susceptibilities to SCC and sensitized 309S ss have not susceptibilities in the simulated disposal condition. On the other hand, no specimen was susceptible to SCC in deionized water even with gamma-ray irradiation. (author)

  5. Neutron and gamma ray irradiation effects on interlaminar shear strength of insulation materials with cyanate ester-epoxy blended resin

    International Nuclear Information System (INIS)

    A large scale fusion device like ITER requires high performance electric insulation materials against gamma ray and neutron irradiation, since fusion neutrons will reach superconducting magnets and activate them. Cyanate ester resin has been studied as a strong candidate for a new insulation material for fusion devices, and it has been clarified that the blended resin with epoxy has a potential to survive a design period in the radiation environment. This paper describes the results of molecular structure analysis of the blended resin, heat flux measurements by differential scanning calorimetry and the gamma ray and the fission neutron irradiation effects on interlaminar shear strength (ILSS) at 77 K. The gamma ray irradiation of 10 MGy did not change the ILSS significantly, but the neutron fluence of 1.0 x 1022 n/m2 (>0.1 MeV) with over 400 MGy degraded the ILSS. It suggests that cyanurate (triagine ring) will have a resistance against irradiation but oxazolidinon will lose the resistance after heavy irradiation.

  6. Effect of {gamma}-ray irradiation of the cell growth and the change of pigment contents of Phaeodactylum tricornutum

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Takaharu; Kubodera, Akiko [Science Univ. of Tokyo (Japan). Faculty of Pharmaceutical Science; Kikuchi, Masako; Kawakami, Yasushi

    1997-03-01

    The effects of gamma-ray irradiation to a marine pennate diatom Phaeodactylum tricornutum were investigated. The diatom is rich in carotenoid pigments, fucoxanthin and {beta}-carotene which are known to have antioxidative activity in vitro. The cell growth and the pigment contents were measured under various irradiation conditions. In every run, the algae grew 20 to 30-fold in 5 days after irradiation of up to 193 Gy, which was acutely fatal to animal body or cells. The cell growth and the pigment contents showed little differences between irradiated samples and its control when they were exposed to gamma-ray of up to 100 Gy for 12 min. But 60 min irradiation gave inhibitory effects on the cell growth and the fucoxanthin content decreased when 1.0 Gy dose was given. Conversely, low doses ranging from 0.2 Gy to 0.5 Gy did simulate the cell growth compared to its control though the doses over 0.5 Gy showed inhibitory effects. In contrast to the cell growth, both the amounts and contents of {beta}-carotene or fucoxanthin, however, considerably decreased under these low doses. Fucoxanthin decreased while {beta}-carotene increased compared to the control when the algae was exposed to gamma-ray for 60 min with over 1.0 Gy. There was no significant correlation between the doses and {beta}-carotene content below 1.0 Gy. (author)

  7. Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

    International Nuclear Information System (INIS)

    An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D10) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

  8. Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Miyahara, Michiko; Miyahara, Makoto [National Inst. of Health Sciences, Tokyo (Japan)

    2002-10-01

    An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D{sub 10}) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

  9. Peroxidation of blood plasma lipids after various regimes of external irradiation of rats by 60Co gamma-rays

    International Nuclear Information System (INIS)

    Peroxidation products of lipids in blood plasma of laboratory rats are studied after one-time, fractional and long-term external irradiation of the rats by 60Co gamma-rays. It was found, that different modes of a total external irradiation of rats lead to prominent features of dynamics and dose dependences of radio gene changes of the content of peroxidation products of lipids in blood plasma. It was shown that fractional irradiation is less effective for an organism, whereas long-term irradiation causes essentially big radiation induced changes than one-time action of radiation.

  10. Peptide structure modifications. Effect of radical species generated by controlled gamma ray irradiation approach

    International Nuclear Information System (INIS)

    The present work aimed at evaluating the radiolysis effect upon a set of peptides, most of them involved in physiological functions. To generate reactive radical species, a Co60 source (up to 15 kGy) was used for controlled gamma irradiation of some peptide solutions including derivatives attaching the stable free radical Toac (2,2,6,6-tetramethypiperidine-1-oxyl-4-amino-4-carboxylic acid). Regardless of the peptide sequence, a nonlinear and progressive degradation of a total of nine peptides was detected. The results were interpreted in the light of the half-life dose (D1/2) parameter which represents the dose necessary for 50% peptide structure degradation. The vasoactive angiotensin II (AngII)'s analogue Ang-(1-7) showed greater stability towards gamma ray radiation than bradykinin (BK), Toac0-BK, Pro4-BK (D1/2 around 4 and 2 kGy, respectively) which decreased to about 0.5-1.0 kGy in the case of acetyl-?-melanocyte-stimulating hormone (Ac-?-MSH) and substance P (SP). In terms of peptide structural modifications, the data acquired from different analytical methods suggested a Phe to Tyr (or its ortho and/or meta isomers) transformation as a consequence of the hydroxyl moiety insertion. Noteworthy, this effect seemed to be position-dependent as only Phe located at or near the C-terminal portion seemed to display this transformation. In contrast, Met is comparatively more easily oxidized, thus allowing to conclude that gamma irradiation may induce a complex position and/or sequence-dependent effect on peptides. As previously applied for BK, some irradiated peptides were submitted to their by-products purification, indeed a complementary target of the present approach for development of uncommon analogues for further structure-function investigation. (author)

  11. Induction of drought tolerance in tomato using 60Co gamma ray irradiation

    International Nuclear Information System (INIS)

    Drought is one of the environmental limitations that affects, on a higher degree, the production of different crops including tomato. A tomato breeding program was started to develop varieties suitable for growing under low water input conditions, which is not only important for saving this valuable liquid but also for diversifying food production in drought-affected areas. Two Cuban tomato varieties (INCA 9-1 and Amalia) were irradiated by 60Co gamma rays at doses of 300 and 500 Gy. In M2 generation, plants were cultivated in two zones of the country (Holguin and Havana province) in the months of lower precipitation (December-March). Irrigation was made three times at transplanting stage. Plants were grown in the short rainy season to keep suitable conditions for a promising genotype selection. During the following six generations selection was made for genotypes of high-yield, large fruit, high yield, disease resistance and fruit quality. In M6 generation, evaluation was conducted under water stress conditions for 60 plants of each of the best mutant lines, four of them from INCA 9-1 variety and three from Amalia variety.The mutant lines M15, M17 and M19 have been further evaluated in different areas of the country and they have shown very good behavior

  12. Stability Test For Sorghum Mutant Lines Derived From Induced Mutations with Gamma-Ray Irradiation

    Directory of Open Access Journals (Sweden)

    S. Human

    2011-12-01

    Full Text Available Sorghum breeding program had been conducted at the Center for the Application of Isotopes and Radiation Technology, BATAN. Plant genetic variability was increased through induced mutations using gamma-ray irradiation. Through selection process in successive generations, some promising mutant lines had been identified to have good agronomic characteristics with high grain yield. These breeding lines were tested in multi location trials and information of the genotypic stability was obtained to meet the requirements for officially varietal release by the Ministry of Agriculture. A total of 11 sorghum lines and varieties consisting of 8 mutant lines derived from induced mutations (B-100, B-95, B-92, B-83, B-76, B-75, B-69 and Zh-30 and 3 control varieties (Durra, UPCA-S1 and Mandau were included in the experiment. All materials were grown in 10 agro-ecologically different locations namely Gunungkidul, Bantul, Citayam, Garut, Lampung, Bogor, Anyer, Karawaci, Cianjur and Subang. In each location, the local adaptability test was conducted by randomized block design with 3 replications. Data of grain yield was used for evaluating genotypic stability using AMMI approach. Results revealed that sorghum mutation breeding had generated 3 mutant lines (B-100, B-76 and Zh-30 exhibiting grain yield significantly higher than the control varieties. These mutant lines were genetically stable in all locations so that they would be recommended for official release as new sorghum varieties to the Ministry of Agriculture

  13. Fillers for gamma ray-irradiated EPR and ultralow frequency dielectric characteristics

    International Nuclear Information System (INIS)

    Aiming at the diagnosis of the radiation deterioration of electric power cables and wires by utilizing residual voltage, the relation of the amount of gamma ray irradiation with residual voltage has been examined for the EPR of practical mixing proportion by the authors. Moreover, as the characteristics or physical quantities used for judging the deterioration, the dielectric characteristics in ultralow frequency region and insulation resistance were taken up, and the method of analytically determine them from the results of measuring residual voltage was proposed. When the results obtained by this analytical method were compared with the results of leak current and discharge current, good agreement was obtained. However, since many kinds of fillers are added to these samples with practical mixing proportion in large quantities, it was unable to examine in detail the physical mechanism of depolarization which becomes the cause of generating residual voltage. This time, the discharge current was measured for the samples of EPR filled with only one kind of filler, hard clay, and the modeling of depolarization mecanism was attempted. The results are reported. (K.I.)

  14. A {gamma}-ray irradiation route to fabricate monodisperse zinc sulfide hollow spheres using silica as templates

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Yongbin [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi Wenfang [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)]. E-mail: wfshi@ustc.edu.cn; Gong Ming [Lab of Mechanical and Material Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yu Fei [Lab of Mechanical and Material Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Chen Tiantian [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2005-12-15

    The monodisperse submicrometer zinc sulfide (ZnS) hollow spheres were synthesized by {gamma}-ray irradiation at room temperature, using monodisperse silica spheres as the templates. In order to obtain ZnS hollow spheres, the ZnS-coated SiO{sub 2} core-shell particles were prepared through {gamma}-ray irradiation deposition in an aqueous containing zinc acetate and sulfide, released through the hydrolysis of thioacetamide, followed by dissolving the SiO{sub 2} cores using hydrofluoric acid. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-vis spectroscopy were used to characterize these nanoparticles, indicating the formation of core-shell colloidal spheres, as well as hollow spheres.

  15. Radiolytic degradation of hexabromocyclododecane in waste water from thermal insulation-treatment factory with gamma ray irradiation

    International Nuclear Information System (INIS)

    Radiolytic, and radiolytic/biological decompositions of hexabromocyclododecane (HBCD) in primary and ultimate waste waters from a thermal insulation-treatment process and a factory of polyester process are studied with gamma ray irradiation. Concentrations and degradation ratios of HBCD, and Br- concentrations are determined before and after gamma ray irradiation. Also, total organic carbon (TOC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) are determined to evaluate the decomposition of total organic compounds. As a result, about 72.5% of HBCD in ultimate waste water were decomposed with dose of 100 kGy. Furthermore, about 98% of HBCD, nearly all organic compounds were removed after the combination of radiolytic/biological treatments. (author)

  16. Effect of gamma-ray irradiation in vitro on the inhibition activity of hen's egg white ovomucoid

    International Nuclear Information System (INIS)

    The ovomucoid radiosensitivity is investigated under certain condition (irradiation dose, protein concentration, storage time after irradiation) and it is compared with that of ovomucoid substrate - trypsine. A chromatographically homogeneous ovomucoid preparation was used. The protein concentration of the solutions was determined on a UV-spectrophotometer UNICAM SP 180. The irradiation was performed with a 60Co-gamma-ray source at a dose rate, amounting to 6,6 and 225,2 rads per second, the temperature of the solutions before and during the irradiation and up to the post-irradiation assays were controlled at 00 C. Conclusion has been drawn out that just as other proteins, even though more slightly, the ovomucoid is sensitive to the indirect action of the ionizing, and to high gamma-ray doses in particular. The effect of irradiation depends on the protein concentration in the solution and on the post-irradiation storage time. In addition to the other reasons, such as an increase in the permeability of the cellular membrane and possibly the biosynthesis of the peptidehydrolases in the cell, adaptively intensified, the radioactivity of the natural proteinase inhibitors is the cause for the manifestation of the ''stimulating'' effect of the radioactive irradiation on the activity of proteases when irradiated in vivo. (K.M.)

  17. An atomic force microscopic study of the surfaces of polyethylene and polycarbonate films irradiated with gamma rays

    International Nuclear Information System (INIS)

    The changes in the surface topology of polyethylene and polycarbonate films irradiated with gamma rays up to 500 kGy doses have been investigated with Atomic Force Microscopy. The cumulative effect of irradiation has been followed by analyzing exactly the same region of the surfaces after every irradiation step. This has been achieved by applying an addressing operation on the surfaces of virgin polymers. The increase in surface roughness showed a sudden increase up to100 kGy dose and remained almost unchanged thereafter. The radiation-induced topological changes are found to correlate with the chemical effects of these rays. (author)

  18. Measuring of hands irradiation by gamma-ray and positron of personnel of the departments of nuclear medicine by TL dosimetry

    International Nuclear Information System (INIS)

    The authors carried out measurement of hands irradiation by gamma-ray and positron of personnel of the departments of nuclear medicine by TL dosimetry. It was found that the estimated radiation doses are underestimated.

  19. Comparison of gamma ray and electron beam irradiation on extraction yield, morphological and antioxidant properties of polysaccharides from tamarind seed

    Science.gov (United States)

    Choi, Jong-il; Kim, Jae-Kyung; Srinivasan, Periasamy; Kim, Jae-Hun; Park, Hyun-Jin; Byun, Myung-Woo; Lee, Ju-Woon

    2009-07-01

    Tamarind ( Tamarindus indica L) seed polysaccharide (TSP) is of great important due to its various biological activities. The present investigation was carried out to compare extraction yield, morphological characteristics, average molecular weights and antioxidant activities of TSP from gamma- and electron beam (EB)-irradiated tamarind kernel powder. The tamarind kernel powder was irradiated with 0, 5 and 10 kGy by gamma ray (GR) and electron beam, respectively. The extraction yield of TSP was increased significantly by EB and GR irradiation, but there was no significant difference between irradiation types. Morphological studies by scanning electron microscope showed that TSP from GR-irradiated tamarind seed had a fibrous structure, different from that of EB irradiated with a particle structures. The average molecular weight of TSP was decreased by the irradiation, and EB treatment degraded more severely than GR. Superoxide radical scavenging ability and total antioxidant capacity of EB-treated TSP showed higher than those of GR-treated TSP.

  20. Comparison of gamma ray and electron beam irradiation on extraction yield, morphological and antioxidant properties of polysaccharides from tamarind seed

    International Nuclear Information System (INIS)

    Tamarind (Tamarindus indica L) seed polysaccharide (TSP) is of great important due to its various biological activities. The present investigation was carried out to compare extraction yield, morphological characteristics, average molecular weights and antioxidant activities of TSP from gamma- and electron beam (EB)-irradiated tamarind kernel powder. The tamarind kernel powder was irradiated with 0, 5 and 10 kGy by gamma ray (GR) and electron beam, respectively. The extraction yield of TSP was increased significantly by EB and GR irradiation, but there was no significant difference between irradiation types. Morphological studies by scanning electron microscope showed that TSP from GR-irradiated tamarind seed had a fibrous structure, different from that of EB irradiated with a particle structures. The average molecular weight of TSP was decreased by the irradiation, and EB treatment degraded more severely than GR. Superoxide radical scavenging ability and total antioxidant capacity of EB-treated TSP showed higher than those of GR-treated TSP.

  1. Comparison of gamma ray and electron beam irradiation on extraction yield, morphological and antioxidant properties of polysaccharides from tamarind seed

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong-il [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Kim, Jae-Kyung [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Graduate school of Food and Biotechnology, Korea University, Seoul 146-701 (Korea, Republic of); Srinivasan, Periasamy; Kim, Jae-Hun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Park, Hyun-Jin [Graduate school of Food and Biotechnology, Korea University, Seoul 146-701 (Korea, Republic of); Byun, Myung-Woo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Lee, Ju-Woon [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of)], E-mail: sjwlee@kaeri.re.kr

    2009-07-15

    Tamarind (Tamarindus indica L) seed polysaccharide (TSP) is of great important due to its various biological activities. The present investigation was carried out to compare extraction yield, morphological characteristics, average molecular weights and antioxidant activities of TSP from gamma- and electron beam (EB)-irradiated tamarind kernel powder. The tamarind kernel powder was irradiated with 0, 5 and 10 kGy by gamma ray (GR) and electron beam, respectively. The extraction yield of TSP was increased significantly by EB and GR irradiation, but there was no significant difference between irradiation types. Morphological studies by scanning electron microscope showed that TSP from GR-irradiated tamarind seed had a fibrous structure, different from that of EB irradiated with a particle structures. The average molecular weight of TSP was decreased by the irradiation, and EB treatment degraded more severely than GR. Superoxide radical scavenging ability and total antioxidant capacity of EB-treated TSP showed higher than those of GR-treated TSP.

  2. Quality of gamma ray-irradiated iceberg lettuce and treatments to minimize irradiation-induced disorders

    Science.gov (United States)

    Irradiation of Iceberg lettuce was recently approved by the FDA to enhance microbial safety and to extend shelf-life at doses up to 4 kGy. However, the radiation tolerance of whole head lettuce is unclear. The present study was conducted to investigate the effects of irradiation on the quality of he...

  3. Simulation of gamma-ray irradiation of lettuce leaves in a 137Cs irradiator using MCNP

    International Nuclear Information System (INIS)

    Ionizing radiation effectively reduces the number of common microbial pathogens in fresh produce. However, the efficacy of the process for pathogens internalized into produce tissue is unknown. The objective of this study was to understand gamma irradiation of lettuce leaf structure exposed in a 137Cs irradiator using MCNP. The simulated 137Cs irradiator is a self-shielded device, and its geometry and sources are described in the MCNP input file. When the irradiation chamber is filled with water, lower doses are found at the center of the irradiation volume and the dose uniformity ratio (maximum dose/minimum dose) is 1.76. For randomly oriented rectangular lettuce leaf segments in the irradiation chamber, the dose uniformity ratio is 1.25. It shows that dose uniformity in the Cs irradiator is strongly dependent of the density of the sample. To understand dose distribution inside the leaf, we divided a lettuce leaf into a low density (flat) region (0.72 g/cm3) and high density (rib) region (0.86 g/cm3). Calculated doses to the rib are 61% higher than doses to the flat region of the leaf. This indicates that internalized microorganisms can be inactivated more easily than organisms on the surface. This study shows that irradiation can effectively reduce viable microorganism internalized in lettuce. (author)

  4. Effects of gamma-ray irradiation on optical properties of ZnO-PbO-B2O3 glasses

    DEFF Research Database (Denmark)

    Sharma, G.; Thind, K.S.; Manupriya, -; Klare, H.S.; Narang, S.B.; Gerward, Leif; Dangwal, V.K.

    2006-01-01

    Effects of gamma-ray irradiation on some optical properties of xZnO(.)2xPbO(.)(1-3x)B2O3 glasses have been studied in the wavelength range 300-800 nm. Decrease in transmittance indicates the formation of color-center defects. Values for the energy-band gap, the width of the energy tail above the mobility gap and the cut-off wavelength have been measured before and after irradiation. Changes in the optical properties are explained in terms of radiation-induced structural defects and the compositi...

  5. Production of acetic acid from ethanol solution by acetobactor acetigenum and effect of gamma-ray irradiation on the bacteria

    International Nuclear Information System (INIS)

    A preliminary study on fermentation of acetic acid by S. cerevisiae and A. acetigenum was carried out to obtain information to develop the effective utilization technology of agricultural liquid wastes. Aqueous solutions of glucose and/or ethanol were used as a model of agricultural liquid waste. The effect of gamma-ray irradiation on A. acetigenum for enhancement of the fermentation was also examined. In this study, irradiated A. acetigenum had activity to produce acetic acid even after loss the activity to grow. (author)

  6. Experimental validation of the new nanodosimetry-based cell survival model for mixed neutron and gamma-ray irradiation

    International Nuclear Information System (INIS)

    The new nanodosimetry-based linear-quadratic (LQ) formula has been reviewed for mixed-LET irradiation. V-79 Chinese hamster cells have been irradiated with a mixed-LET field of fission neutrons and gamma rays at University of Maryland Training Reactor (MUTR). The results show that the experimental survival curve agrees well with that predicted by the new nanodosimetry-based LQ model. The experimental study described in this note, therefore, serves as a validation for the new model to be used for mixed-LET radiotherapies, e.g. 252Cf brachytherapy

  7. Array-type sensor to determine corrosive conditions in high temperature water under gamma rays irradiation

    International Nuclear Information System (INIS)

    One of the problems to determine electrochemical corrosion potential (ECP) in high temperature water under irradiation is to apply long-lived and reliable reference electrodes. In order to avoid troubles due to the reference electrode, a new concept to determine ECP without the reference electrode has been proposed. Several metal plates are applied as working electrodes and at the same time as the reference electrodes. Potential of the metal plates with stable oxide films on their surfaces show stable values in high temperature water. As a result of the combination of their potential values, ECP of each metal can be determined without any specific reference electrode. Array-type sensors consisting of several metal plates, e.g., Fe, Ni, Cr, Zr, Pt, Pd, Re, Ir, with well developed oxide films on their surface were prepared for ECP measurement in high temperature water under neutron/gamma ray irradiations. In order to confirm the feasibility of this concept, responses of the redox potentials of the pure metals to changes in the simulated BWR reactor water conditions were measured and the ECP was determined by the differences in potentials between a couple of metal plates. Major conclusions of the study are as follows: 1) The redox potentials of the Fe, Pt, Zr, Ir, Pd, and Re electrodes showed the different dependences on the changes in O2 and H2O2 concentrations. The redox potentials of the electrodes increased as the oxidant concentrations increased except for Zr electrode. The potential of the Zr electrode was kept the very low potential at the wide range of O2 and H2O2 concentrations differed form the other electrodes. 2) It was estimated that the redox potential of highly soluble metal may be increased, while that of low soluble metal may be decreased by an oxide film. The stable oxide film would cause the stable potential response of the electrode with oxide film. 3) The relationship between the oxidant concentrations and the redox potentials of the electrodes were determined by the theoretical calculations of the anodic and cathodic current densities to determine the ECP using the basic concept of the array-type sensor. 4) The feasibility of the concept for a new array-type sensor to determine the ECP was confirmed by the comparison between the ECP obtained by the array-type sensor and the measured ECP. To improve the sensor, more basic data and the optimization of the electrodes are required.

  8. The effects of prenatal irradiation with a low doses of gamma-rays on spatial memory in adult rats

    International Nuclear Information System (INIS)

    Pregnant females of Wistar-strain rats were irradiated (sham-irradiated) with a dose of 1 Gy of gamma-rays on the 16th day of pregnancy. The progeny of both irradiated and control animals was tested in Morris' water maze for spatial memory at age of 4 months. The time needed to find the hidden platform and the swimming-track were recorded using a computer aided video-tracking method. The test was repeated after 24 hours (short-time memory) and after one week (long-time memory). In short-time memory test the irradiated females needed in comparison with controls a statistically significantly longer time and a longer swimming track to find the platform. No significant differences were found in male. In long-term memory test no significant differences in both parameters followed were found in either of sexes. The results suggest, that irradiation with a low dose of gamma-rays during the period of the embryonic development of the brain can negatively influence the short-term spatial memory, but has no effect on long-time memory in rats. (authors)

  9. Radiosensitivity of apricot budsticks exposed to acute gamma rays and nursery observations on the second vegetative generation from irradiated buds

    International Nuclear Information System (INIS)

    Varietal improvement is essential if a new impetus is to be given to the French apricot crop. We have accordingly started a mutation breeding programme by bud irradiation. Because of the scarcity of bibliographical data, the first step was to study the budwood radiosensitivity of the apricot cultivars used as starting material. Budsticks of various cultivars were exposed to increasing doses of acute gamma rays. The physiological effects induced by irradiation were evaluated from bud survival and growth. These results allowed us, in the first instance, to fix the optimal dose range for dormant buds irradiated at 6 to 7 Gy/mm. Observations in the nursery on scions from the second vegetative generation (V2) already showed the limits of bud irradiation. Further observations in the orchard are need to estimate the value of this method for apricot breeding

  10. Effects of oxygen and moisture content on the radiation damage in barley seeds irradiated with fast neutrons and gamma rays

    International Nuclear Information System (INIS)

    In gamma-irradiated barley seeds the effect of moisture content seems to modify the oxygen effect. If gamma-irradiated seeds (4% H2O content) are soaked in oxygen-free water before being transferred to oxygenated water, the oxygen-sensitive centres decay. The decay rate is a function of temperature and is shown to be most likely due to how fast the target molecules are hydrated. When low moisture content seeds were irradiated with fast neutrons in the SNIF, a moisture content effect was also obtained. However, contrary to what was found with gamma-irradiated seeds, no effect of oxygen was obtained. This excludes the possibility that gamma-contamination caused the moisture content effect. A model explaining the difference between the effect of neutrons and gamma-rays, respectively, is discussed. (author). 13 refs, 1 fig., 2 tabs

  11. Evaluation of induced radioactivity in 10 MeV-electron irradiated spices, (1); [gamma]-ray measurement

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Shibata, Setsuko; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

    1994-02-01

    Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by [gamma]-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H[sub 50] according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from [sup 40]K contained in the samples. (author).

  12. Effect of electron and gamma-ray irradiation on the chemical composition and atomic distribution of copper- and iron-based alloy

    International Nuclear Information System (INIS)

    This paper reports that the oxygen, hydrogen, carbon, nitrogen, and sulfur contents of steels and alloys can vary as a result of irradiation by electrons and gamma rays at comparatively low temperatures. As this takes place, the materials can be either saturated with these elements, or these elements can be removed from the irradiated materials, depending on the irradiation medium. Transformations are initiated as a result of radiation-stimulated oxygenation of copper-iron, iron-manganese, and iron-nickel alloys irradiated by gamma rays

  13. Formation of CO2 gas and OH groups in CR-39 plastics due to gamma-ray and ions irradiation

    International Nuclear Information System (INIS)

    FT-IR spectral studies have been made for CR-39 detectors irradiated by gamma-rays, protons and carbon ions. An absorption peak for CO2 appeared and grew with the fluence. The peak height was found to decrease gradually by storing in air. Absorbance of the OH group produced by ion bombardment was observed separately from that of adsorbed water using an FT-IR system on the beam line. The concentration of OH group would govern the rate of penetration of chemical agents along the track

  14. Two CdZnTe Detector-Equipped Gamma-ray Spectrometers for Attribute Measurements on Irradiated Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hartwell, John Kelvin; Winston, Philip Lon; Marts, Donna Jeanne; Moore-McAteer, Lisa Dawn; Taylor, Steven Cheney

    2003-04-01

    Some United States Department of Energy-owned spent fuel elements from foreign research reactors (FRRs) are presently being shipped from the reactor location to the US for storage at the Idaho National Engineering and Environmental Laboratory (INEEL). Two cadmium zinc telluride detector-based gamma-ray spectrometers have been developed to confirm the irradiation status of these fuels. One spectrometer is configured to operate underwater in the spent fuel pool of the shipping location, while the other is configured to interrogate elements on receipt in the dry transfer cell at the INEELs Interim Fuel Storage Facility (IFSF). Both units have been operationally tested at the INEEL.

  15. Dwarf Rice Mutant Derived from 0.2 kGy Gamma Rays Irradiated Seeds of Atomita 4 Variety

    International Nuclear Information System (INIS)

    Dwarf rice mutant was obtained when Atomita 4 seeds were irradiated by 0.2 kGy gamma rays. The results of segregation analyses in F2 populations and F3 lines derived from reciprocal crosses of mutant and Atomita 4 suggested that the dwarf was controlled by a single recessive gene. This gene was not located on rice cytoplasmic genome but on nuclear genome. The gene for dwarf obtained in this study tentatively could be assumed as a new finding until the allelic relationships with other dwarf genes are verified. (author)

  16. Modifications of heterosis in hybrids between two inbred lines of maize (Zea Mays L.) irradiated with gamma rays

    International Nuclear Information System (INIS)

    A study of the effect of gamma radiation (3700 R) on heterosis in maize was carried out. Seeds of two inbred lines were irradiated with 3700R and crossed. Hybrid seeds obtained from these crossings were sown in the field according to a balanced lattice square design, 4 x 4 with 10 repetitions, and various quantitative characters were scored and analyzed. It is concluded that gamma-rays may modify combining ability o these inbred lines, accompanied by change in plant height, car number, ear length, weight of 100 kernels and husked car weight of the hybrids. (Author)

  17. Positron and Gamma-Ray Creation using the Texas Petawatt Laser Irradiating Gold Targets

    Science.gov (United States)

    Liang, Edison; Taylor, Devin; Clarke, Taylor; Henderson, Alexander; Chaguine, Petr; Wang, Xin; Dyer, Gilliss; Serratto, Kristina; Riley, Nathan; Donovan, Michael; Ditmire, Todd

    2012-10-01

    We report preliminary results of the positron and gamma-ray creation experiment performed at the Texas Petawatt Laser (TPW) during the summer of 2012. Of the shots using gold targets, preliminary results suggest that positrons were detected in many of the shots. TPW was operating at around 100 J and 0.5 -- 0.8 PW during this experiment, and 25% of the shots achieved peak intensity exceeding 10^21W.cm-2. We will report the measured positron spectra, positron angular distribution and positron to hot electron ratio, inferred positron yield and in-situ positron density. The positron energy data will be compared to simultaneous TNSA proton energy data to model sheath acceleration mechanisms. We also measured the bremsstrahlung gamma-ray spectra and angular distributions from the gold targets, using a combination of dosimeters, filter stack spectrometers and forward Compton spectrometer. Target activation data will also be reported.

  18. The influence of gamma rays irradiation on chlorophyll mutation and genetic variability of agronomic characters in soybean plant

    International Nuclear Information System (INIS)

    Seeds of soybean mutant line No. 13/PsJ with 12% moisture content were irradiated by 0,10;0,20;0.30 and 0.40 kGy of gamma rays treatment. Number of irradiated seed for each treatment was 1500 seeds. Irradiated of seeds were planted in the 4m X 5m plot size with 0,20m x 0,40m spacing and two seed each hole and were planted as M-1 plants in the wet season of 1996/1997 at PAIR field experiment in Pasar Jumat, Jakarta. The experiment was designed Randomized Block Design with three replication Plans of M-1 generation were harvested individuality and were planted as known M2 plants in the next generation in dry season of 1997 at PAIR field experiment. Seven days planting the chlorophyll mutation of plants were recorded by Frydenberg method and the genetic variability of plant height, number of fertile pods and nodes were calculated by Singh and Chaudhary formula. Results of the experiment showed that chlorophyll mutation and genetic variability of plant height and number of fertile pods could be improved be 0.10 and 0,20 kGy of gamma rays treatment. (authors)

  19. Magnetic composite nanoparticle of Au/?-Fe2O3 synthesized by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Magnetic composite nanoparticle of Au/?-Fe2O3 was synthesized in an aqueous phase using gamma-ray. Connection between gold and ?-Fe2O3 was confirmed by the magnetic separation technique. TEM observation shows that 5-nm gold particles were dispersed on 20-nm ?-Fe2O3 particles. The nanoparticles adsorbed a water-soluble mercaptan, glutathione, and was manipulated by an external magnetic field. (author)

  20. Gamma-ray irradiation and post-irradiation at room and elevated temperature response of pMOS dosimeters with thick gate oxides

    Directory of Open Access Journals (Sweden)

    Pejovi? Mom?ilo M.

    2011-01-01

    Full Text Available Gamma-ray irradiation and post-irradiation response at room and elevated temperature have been studied for radiation sensitive pMOS transistors with gate oxide thickness of 100 and 400 nm, respectively. Their response was followed based on the changes in the threshold voltage shift which was estimated on the basis of transfer characteristics in saturation. The presence of radiation-induced fixed oxide traps and switching traps - which lead to a change in the threshold voltage - was estimated from the sub-threshold I-V curves, using the midgap technique. It was shown that fixed oxide traps have a dominant influence on the change in the threshold voltage shift during gamma-ray irradiation and annealing.

  1. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Ferreto, H. F. R., E-mail: hferreto@ipen.br, E-mail: ana-feitoza@yahoo.com.br; Oliveira, A. C. F., E-mail: hferreto@ipen.br, E-mail: ana-feitoza@yahoo.com.br; Parra, D. F., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br; Lugo, A. B., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br [Center of Chemistry and Environment, Institute of Energy and Nuclear Research - IPEN (Brazil); Gaia, R., E-mail: renan-gaia7@hotmail.com [Faculdades Oswaldo Cruz (Brazil)

    2014-05-15

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

  2. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    Science.gov (United States)

    Ferreto, H. F. R.; Oliveira, A. C. F.; Gaia, R.; Parra, D. F.; Lugo, A. B.

    2014-05-01

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of 60Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

  3. Tuning the grade of graphene: Gamma ray irradiation of free-standing graphene oxide films in gaseous phase

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: Gaseous gamma ray irradiation on graphene oxide. Impact of the radicals formation on the surface functionalization. Evaluation of morphological and crystallinity changes across the material. New route to the formation of pre-assembled graphene oxide 3D architectures. - Abstract: A direct approach to functionalize and reduce pre-shaped graphene oxide 3D architectures is demonstrated by gamma ray irradiation in gaseous phase under analytical grade air, N2 or H2. The formation of radicals upon gamma ray irradiation is shown to lead to surface functionalization of the graphene oxide sheets. The reduction degree of graphene oxide, which can be controlled through varying the ?-ray total dose irradiation, leads to the synthesis of highly crystalline and near defect-free graphene based materials. The crystalline structure of the graphene oxide and ?-ray reduced graphene oxide was investigated by x-ray diffraction and Raman spectroscopy. The results reveal no noticeable changes in the size of sp2 graphitic structures for the range of tested gases and total exposure doses suggesting that the irradiation in gaseous phase does not damage the graphene crystalline domains. As confirmed by X-ray photoemission spectroscopy, the C/O ratio of ?-ray reduced graphene oxide is increasing from 2.37 for graphene oxide to 6.25 upon irradiation in hydrogen gas. The removal of oxygen atoms with this reduction process in hydrogen results in a sharp 400 times increase of the electrical conductivity of ?-ray reduced graphene oxide from 0.05 S cm?1 to as high as 23 S cm?1. A significant increase of the contact angle of the ?-ray reduced graphene oxide bucky-papers and weakened oxygen rich groups characteristic peaks across the Fourier transform infrared spectra further illustrate the efficacy of the ?-ray reduction process. A mechanism correlating the interaction between hydrogen radicals formed upon ?-ray irradiation of hydrogen gas and the oxygen rich groups on the surface of the graphene oxide bucky-papers is proposed, in order to contribute to the synthesis of reduced graphene materials through solution-free chemistry routes

  4. Tuning the grade of graphene: Gamma ray irradiation of free-standing graphene oxide films in gaseous phase

    Energy Technology Data Exchange (ETDEWEB)

    Dume, Ludovic F., E-mail: ludovic.dumee@deakin.edu.au [Institute for Frontier Materials, Deakin University, Pigdons Road, Waurn Ponds 3216 (Australia); Feng, Chunfang; He, Li; Allioux, Francois-Marie; Yi, Zhifeng; Gao, Weimin [Institute for Frontier Materials, Deakin University, Pigdons Road, Waurn Ponds 3216 (Australia); Banos, Connie; Davies, Justin B. [Australian Nuclear Science and Technology Organisation, Illawarra Road, Lucas Heights 2234 (Australia); Kong, Lingxue, E-mail: lingxue.kong@deakin.edu.au [Institute for Frontier Materials, Deakin University, Pigdons Road, Waurn Ponds 3216 (Australia)

    2014-12-15

    Graphical abstract: - Highlights: Gaseous gamma ray irradiation on graphene oxide. Impact of the radicals formation on the surface functionalization. Evaluation of morphological and crystallinity changes across the material. New route to the formation of pre-assembled graphene oxide 3D architectures. - Abstract: A direct approach to functionalize and reduce pre-shaped graphene oxide 3D architectures is demonstrated by gamma ray irradiation in gaseous phase under analytical grade air, N{sub 2} or H{sub 2}. The formation of radicals upon gamma ray irradiation is shown to lead to surface functionalization of the graphene oxide sheets. The reduction degree of graphene oxide, which can be controlled through varying the ?-ray total dose irradiation, leads to the synthesis of highly crystalline and near defect-free graphene based materials. The crystalline structure of the graphene oxide and ?-ray reduced graphene oxide was investigated by x-ray diffraction and Raman spectroscopy. The results reveal no noticeable changes in the size of sp2 graphitic structures for the range of tested gases and total exposure doses suggesting that the irradiation in gaseous phase does not damage the graphene crystalline domains. As confirmed by X-ray photoemission spectroscopy, the C/O ratio of ?-ray reduced graphene oxide is increasing from 2.37 for graphene oxide to 6.25 upon irradiation in hydrogen gas. The removal of oxygen atoms with this reduction process in hydrogen results in a sharp 400 times increase of the electrical conductivity of ?-ray reduced graphene oxide from 0.05 S cm{sup ?1} to as high as 23 S cm{sup ?1}. A significant increase of the contact angle of the ?-ray reduced graphene oxide bucky-papers and weakened oxygen rich groups characteristic peaks across the Fourier transform infrared spectra further illustrate the efficacy of the ?-ray reduction process. A mechanism correlating the interaction between hydrogen radicals formed upon ?-ray irradiation of hydrogen gas and the oxygen rich groups on the surface of the graphene oxide bucky-papers is proposed, in order to contribute to the synthesis of reduced graphene materials through solution-free chemistry routes.

  5. Monte Carlo simulation of prompt gamma-ray spectra from depleted uranium under D-T neutron irradiation and electron recoil spectra in a liquid scintillator detector

    CERN Document Server

    Qin, Jianguo; Liu, Rong; Zhu, Tonghua; Zhang, Xinwei; Ye, Bangjiao

    2015-01-01

    To overcome the problem of inefficient computing time and unreliable results in MCNP5 calculation, a two-step method is adopted to calculate the energy deposition of prompt gamma-rays in detectors for depleted uranium spherical shells under D-T neutrons irradiation. In the first step, the gamma-ray spectrum for energy below 7 MeV is calculated by MCNP5 code; secondly, the electron recoil spectrum in a BC501A liquid scintillator detector is simulated based on EGSnrc Monte Carlo Code with the gamma-ray spectrum from the first step as input. The comparison of calculated results with experimental ones shows that the simulations agree well with experiment in the energy region 0.4-3 MeV for the prompt gamma-ray spectrum and below 4 MeVee for the electron recoil spectrum. The reliability of the two-step method in this work is validated.

  6. Effects of gamma-ray irradiation and crevice-like shape on the corrosion of type 316L stainless steel in high-temperature water

    International Nuclear Information System (INIS)

    The irradiation effect to high-temperature water in nuclear power plant has been regarded as one of important issues for preventing corrosion and stress corrosion cracking of plant materials. However, the effects of surface reaction and configurations of material on irradiated high-temperature water chemistry have been studied little because of the difficulty of measuring the environment. In this work, we have done a series of corrosion tests of Type 316L stainless steel in high-temperature water in order to estimate the effects of gamma-ray irradiation and crevice-like shape on the water chemistry. Test specimens immersed in high-temperature water of 288degC were gamma-ray irradiated for 500 hours. The absorbed dose rate of gamma-ray irradiation was estimated to be 30 kGy h-1. The dimensions of the disk-like specimens were 16 mm in diameter by 0.5 mm in thickness. The surfaces of the specimens were mechanically finished with no.800 emery paper. Sets of two specimens attached closely in order to simulate a crevice-like environment were also immersed. The surfaces of the specimens were analyzed using SEM, TEM, and laser Raman spectrometer. The results of surface analyses indicated that gamma-ray irradiation enhanced the precipitation of iron oxide on the surface and the thickness of inner oxide layer became thicker by gamma-ray irradiation. Gamma-ray irradiation also changed the morphology of oxide on the surface faced to the crevice-like environment. (author)

  7. Kinetics of the current response in TlBr detectors under a high dose rate of {gamma}-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gazizov, I. M., E-mail: gazizov@isotop.dubna.ru [OAO Institute of Physical-Technical Problems (Russian Federation); Zaletin, V. M. [Dubna University (Russian Federation); Kukushkin, V. M. [OAO Institute of Physical-Technical Problems (Russian Federation); Kuznetsov, M. S.; Lisitsky, I. S. [OAO GIREDMET (Russian Federation)

    2012-03-15

    The kinetics of the photocurrent response in doped and undoped TlBr samples subjected to irradiation with {gamma}-ray photons from a {sup 137}Cs source with the dose rate 0.033 to 3.84 Gy/min are studied. The crystals were grown by the directional crystallization of the melt method using the Bridgman-Stockbarger technique. The Pb impurity mass fraction introduced into the doped TlBr crystals was 1-10 ppm and amounted to 150 ppm for the Ca impurity. The crystals were grown in a vacuum, in bromine vapors, in a hydrogen atmosphere, and in air. Decay of the photocurrent is observed for extrinsic semiconductor crystals doped with bivalent cations (irrespective of the growth atmosphere), and also for crystals grown in hydrogen and crystals grown in an excess of thallium. The time constant of photocurrent decay {tau} amounted to 30-1400 s and was proportional to resistivity. It is shown that the current response can be related to photolysis in the TlBr crystals during irradiation with {gamma}-ray photons. The energy of hole traps responsible for a slow increase in the photo-current has been estimated and found to be equal to 0.6-0.85 eV.

  8. Comparative study on hematopoietic damage of mice caused by high-dose of gamma-ray irradiation

    International Nuclear Information System (INIS)

    Objective: To study the effect of high-dose of gamma-ray irradiation on hematopoiesis injury and recovery of IRM-2 and C57BL/6 J mouse. Methods: The experiment was designed to study the effects of radiation (4 Gy) on spleen index, CFU-S and DNA damage on the 9 th day of IRM-2 and ICR mice and the effects of radiation (6 Gy) on WBC change and its absolute value on the 45 th days of IRM-2 and C57BL/6 J mice. Results: The IRM-2 mouse spleen index, CFU-S and DNA were higher than ICR mouse on the 9 th days, and there were significant difference in CFU-S and DNA (P<0.01). The IRM-2 mouse WBC, RMC, HGB and HCT were higher than C57BL/6 J mouse on the 45 th days, and there were significant difference (P<0.01). Conclusion: IRM-2 mouse hematopoiesis resumes quicker than C57BL/6 J and ICR do after high-dose of gamma-ray irradiation. (authors)

  9. Dominant lethal mutation induced by continuous irradiation of 60Co gamma rays in mice

    International Nuclear Information System (INIS)

    Female and male mice were exposed to 60Co gamma rays for 10 days, the accumulative doses were 0.396-2.024 and 0.462-2.552 Gy respectively. The number of dominant lethal mutations was calculated as follows: PRE = CL - (ED + LD + VIA). The results showed that Preimplantation Loss (PRE) ranged from 1.222 to 3.714 for female mice and 0.0345 to 2.2308 for male mice. In both cases a linear dose-effect relationship was observed. The PRE of oocytes is 1.66 times higher than that of spermatids

  10. Investigations on the degradation, of visible laser diodes under, gamma-ray irradiation

    International Nuclear Information System (INIS)

    The possible use of semiconductor optoelectronic devices (laser diodes, light emitting diodes, photodetectors) as component parts of remote sensing and diagnostics systems, for different robotic setups in nuclear equipment or for optical fiber-based communication led to the intensive investigations of these components as they operate in radiation environment. We report our research on the evaluation of the gamma-ray induced degradation of several semiconductor laser diodes, emitting at three visible wavelengths, in order to make a preliminary assessment for their possible use in fusion installations

  11. Mutation induction by gamma-rays and carbon ion beam irradiation in banana (Musa spp.): a study with an emphasis on the response to Black sigatoka disease

    International Nuclear Information System (INIS)

    Gamma-rays and carbon ion beam irradiation methods were applied to study critical doses, genetic variability and the response to Black sigatoka disease. 'Cavendish Enano', 'Williams', 'Orito' and 'FHIA-01' cultivars of banana were studied. Both gamma-rays and carbon ion beam irradiation methods had different biological effects when banana explants were exposed to them. In both methods, increased dose caused increased mortality. 'FHIA-01' tolerated high doses of gamma-rays but was susceptible to high doses of carbon ion beam irradiation. The results suggest that the response in 'FHIA-01' can be explored using other dose intervals between 150 and 300 Gy. Weight and height were also reduced drastically when high doses of gamma-rays and carbon ion beams were applied. The LD50 of cultivars 'FHIA-01' and 'Orito' revealed high sensitivity to both gamma-rays and carbon ion beams. DNA deletion in 'FHIA-01' occurred by using gamma-rays at doses of 200 and 300 Gy, suggesting that 'FHIA-01' is definitely a promising cultivar with a high sensitivity response to gamma-ray exposure, and that there is a high chance of improving its fruit quality by mutation induction. Sigmoid drooping leaf, a putative mutation of 'FHIA-01', was generated. This mutation is heritable as mother plant and sucker showed the same characteristics. Future research could be conducted on the relationship of leaf shape to fruit quality and production. Hexaploid cells were detected by flow cytometry (five plants in 'Cavendish Enano' and one in 'Williams'), signifying that chromosome duplication can be induced by carbon ion beams. Variation in the leaves such as being abnormal, double, long, rudimentary, spindled and yellow spotted leaf was visible, suggesting that long-term chronic irradiation (gamma-rays) directly affects active cell division at the meristem level, resulting in severe damage or even death of the meristems. During the juglone toxin experiment on gamma-ray-irradiated plants, 20 plants were selected from the 'Orito' lot, eight in 'Williams' and five in 'Cavendish Enano'. In the carbon ion beam experiments, six plants of 'Williams' and two of 'Cavendish Enano' were selected as possible candidates with a better response to Black sigatoka disease. In addition, following irradiation with a carbon ion beam, a fast growing plant was observed and selected as earliness is an important characteristic for shortening the crop life cycle. Finally, field experiments throughout the whole plant cycle are needed to evaluate mutated traits for fruit quality, yield and post-harvest characteristics for a final selection. (author)

  12. Swelling behavior of ?-ray irradiated elastomers in boiling spray solution

    International Nuclear Information System (INIS)

    Elastomers swelled significantly by water sorption during a simulated LOCA test, and this phenomenon could cause the deterioration of their mechanical and electrical properties. Many factors like as radiation, heat, the composition of spray solution, types of elastomers and their formulation, related to the phenomenon. A relationship between swelling properties of the formulation-known various elastomers and the pre-aging conditions such as radiation dose and thermal aging period was studied by measuring their swelling behaviors in boiling spray solution (water and chemical solution). All eight elastomers tested showed remarkable swelling with an increase of radiation dose when they irradiated in air. A swelling in boiling water was about twice of in chemical solution. Some types of Neoprene and Hypalons had an optimum swelling dose where they showed the maxima. Over this dose, the swelling ratio decreased with dose. When irradiated under vacuum, its swelling ratio became significantly lower than that of exposed in air. This attributed the swelling phenomena closely related to radiation oxidation degradation. (author)

  13. Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy

    International Nuclear Information System (INIS)

    The environment requires polymers that can be degraded by the action of microorganisms. In this work was studied the biodegradation of polyurethane samples derived from vegetable oil (castor oil), which were irradiated with gamma rays 25 kGy and 100 kGy compared with the same polyurethane without being irradiated. Biodegradation of polyurethane was carried out in culture medium containing the fungus Aspergillus niger by 146 days and the result was evaluated using the technique of thermogravimetric analysis, where there was a change of behavior of the curves TGA / DTG occurred indicating that chemical modifications of molecules present in the structure of the polymer chain, thus confirming that the material has undergone the action of microorganisms. (author)

  14. Temperature effects of gamma-rays irradiation on radiation resistance of organic insulator for super conducting magnet in fusion reactor

    International Nuclear Information System (INIS)

    If glass fiber reinforced plastic (GFRP) is used as insulator material for super conducting magnets in a fusion reactor, then the radiation resistance of GFRP in cryogenic environments must be evaluated. The irradiation temperature dependence of radiation degradation of GFRP (Bisphenol-A epoxy resin) was examined. GFRP was exposed to gamma rays at 77K and room temperature. The changes in mechanical properties and the gas evolution were investigated. The flexural strength at break decreased to half of the initial value with 25 MGy at 77K. The evolution of CO and CO2 was much less at 77K than at room temperature. The radiation degradation showed a large dependence on irradiation temperature

  15. Correlation between release of deuterium and annihilation of irradiation defects produced by gamma-ray in Li{sub 2}TiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Kensuke, E-mail: r0233019@ipc.shizuoka.ac.jp [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Kobayashi, Makoto; Fujishima, Tetsuo; Uchimura, Hiromichi; Miura, Ryo [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan); Fujii, Toshiyuki; Yamana, Hajimu [Research Reactor Institute, Kyoto University, Kumatori (Japan); Oya, Yasuhisa; Okuno, Kenji [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka (Japan)

    2013-10-15

    The dependence of irradiation defect density on hydrogen isotope release behaviors in Li{sub 2}TiO{sub 3} was studied. Li{sub 2}TiO{sub 3} was exposed to gaseous deuterium and, thereafter, gamma-ray irradiation was performed with various gamma-ray doses to change the density of irradiation defects. The deuterium release behavior was measured by TDS. The density of the defects and the state of O-D bonds in the sample were elucidated by ESR and FT-IR, respectively. Most of deuterium was adsorbed on the surface or trapped by intrinsic defects after deuterium gas exposure. However, O-D bonds were increased as the gamma-ray dose was increased. In addition, the irradiation defects like E-center, O{sup ?}-center and O{sub 2}{sup ?}-center were observed in gamma-ray irradiated samples. This indicated that the density of irradiation defect control the deuterium stable trapping by oxygen. These facts conclude that tritium release temperature will be shifted toward higher temperature as the operation time increased and irradiation defects are accumulated.

  16. Induction of mutant resistant to alternaria blotch of apple by gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Toji [Hokuriku National Agricultural Experiment Station, Joetsu, Niigata (Japan); Ito, Yuji [National Inst. of Agrobiological Resources, Tsukuba, Ibaraki (Japan); Masuda, Tetsuo [National Institute of Fruit Tree Science, Morioka, Iwate (Japan)

    2000-07-01

    Apple cultivars resistant to Alternaria blotch disease have been produced by cross-breeding, but it is difficult to produce resistance by crossing without changing the properties of cultivar because the gene composition of the cultivar tree is almost heterozygous. This study aimed to investigate the resistant mutation in Alternaria blotch susceptible and semiresistant cultivars. The resistance to Alternaria blotch pathogen or AM toxin is classified into the following three groups: 1) highly sensitive group including Indo, Redgold and Starking delicious, 2) semi-resistant group including Fuji, Orin and Golden delicious and 3) resistant group including Gala and Tsugaru. After gamma ray exposure of 80 Gy (at 5 Gy/hour), AM-toxin insensitive clones were selected in the VM{sub 6} generation. These selected mutants could be rooted and habituated under field conditions. The degree of disease resistance was assessed by AM toxin treatment and Alternaria blotch fungi spore inoculation test. The leaves of these mutants were changed to variegated at high temperature, suggesting that some mutation related to chloroplast might have occurred. Alternaria blotch resistant strains could be produced by exposing to {gamma}ray and selecting with AM toxin in shoot-tip culture system, but the functional effects of the AM toxin in Alternaria blotch and also the mechanism in the mutant lines were still unclear. (M.N.)

  17. On-Line High Dose-Rate Gamma Ray Irradiation Test of the CCD/CMOS Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In this paper, test results of gamma ray irradiation to CCD/CMOS cameras are described. From the CAMS (containment atmospheric monitoring system) data of Fukushima Dai-ichi nuclear power plant station, we found out that the gamma ray dose-rate when the hydrogen explosion occurred in nuclear reactors 1{approx}3 is about 160 Gy/h. If assumed that the emergency response robot for the management of severe accident of the nuclear power plant has been sent into the reactor area to grasp the inside situation of reactor building and to take precautionary measures against releasing radioactive materials, the CCD/CMOS cameras, which are loaded with the robot, serve as eye of the emergency response robot. In the case of the Japanese Quince robot system, which was sent to carry out investigating the unit 2 reactor building refueling floor situation, 7 CCD/CMOS cameras are used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. In the preceding assumptions, a major problem which arises when dealing with CCD/CMOS cameras in the severe accident situations of the nuclear power plant is the presence of high dose-rate gamma irradiation fields. In the case of the DBA (design basis accident) situations of the nuclear power plant, in order to use a CCD/CMOS camera as an ad-hoc monitoring unit in the vicinity of high radioactivity structures and components of the nuclear reactor area, a robust survivability of this camera in such intense gamma-radiation fields therefore should be verified. The CCD/CMOS cameras of various types were gamma irradiated at a dose rate of about 150 Gy/h till these cameras failed. A high dose-rate gamma ray radiation induced speckles in the camera image were heavily observed. In this paper we describe the evolution of their basic characteristics with high dose rate gamma irradiation and shortly explain the observed phenomena

  18. On-Line High Dose-Rate Gamma Ray Irradiation Test of the CCD/CMOS Cameras

    International Nuclear Information System (INIS)

    In this paper, test results of gamma ray irradiation to CCD/CMOS cameras are described. From the CAMS (containment atmospheric monitoring system) data of Fukushima Dai-ichi nuclear power plant station, we found out that the gamma ray dose-rate when the hydrogen explosion occurred in nuclear reactors 1?3 is about 160 Gy/h. If assumed that the emergency response robot for the management of severe accident of the nuclear power plant has been sent into the reactor area to grasp the inside situation of reactor building and to take precautionary measures against releasing radioactive materials, the CCD/CMOS cameras, which are loaded with the robot, serve as eye of the emergency response robot. In the case of the Japanese Quince robot system, which was sent to carry out investigating the unit 2 reactor building refueling floor situation, 7 CCD/CMOS cameras are used. 2 CCD cameras of Quince robot are used for the forward and backward monitoring of the surroundings during navigation. And 2 CCD (or CMOS) cameras are used for monitoring the status of front-end and back-end motion mechanics such as flippers and crawlers. A CCD camera with wide field of view optics is used for monitoring the status of the communication (VDSL) cable reel. And another 2 CCD cameras are assigned for reading the indication value of the radiation dosimeter and the instrument. In the preceding assumptions, a major problem which arises when dealing with CCD/CMOS cameras in the severe accident situations of the nuclear power plant is the presence of high dose-rate gamma irradiation fields. In the case of the DBA (design basis accident) situations of the nuclear power plant, in order to use a CCD/CMOS camera as an ad-hoc monitoring unit in the vicinity of high radioactivity structures and components of the nuclear reactor area, a robust survivability of this camera in such intense gamma-radiation fields therefore should be verified. The CCD/CMOS cameras of various types were gamma irradiated at a dose rate of about 150 Gy/h till these cameras failed. A high dose-rate gamma ray radiation induced speckles in the camera image were heavily observed. In this paper we describe the evolution of their basic characteristics with high dose rate gamma irradiation and shortly explain the observed phenomena

  19. Radio protective effects of calcium channel blockers (deltiazem) on survival of saccharomyces cerevisiae cells irradiated with different doses of gamma rays

    International Nuclear Information System (INIS)

    Results revealed that the necessary dose of gamma rays that leads to 10% of survived cellular population (D10 value) was about 256 Gy. This irradiation dose was used then in all irradiation experiments on culture of S. Cerevisiae cells in which different concentrations of Deltiazem (55, 110, 165 mg/Kg medium) were added before and after irradiation. Results showed that Deltiazem enhances survival percentage of irradiated S. Cerevisiae cultures in a concentration dependent manner. (author)

  20. Effect of gamma-ray irradiation on growth of calli derived from mature embryos or seeds in barley

    International Nuclear Information System (INIS)

    Radiosensitivity of barley varieties as expressed by callus growth was examined after exposure of seeds to gamma-rays and transfer of mature embryos detached from seeds or whole seeds onto medium for the initiation and growth of callus. Marked differences in the value of D50 about 7-fold at maximum were observed among the varieties employed (Figs. 1 a and b). Particularly all the naked varieties used showed much lower values of D50s than the covered ones (Table 1). These results correspond to the level of radiosensitivity expressed by seedling growth after seed irradiation (Figs. 2, 3). A major gene (rs) on chromosome I which has recently been found to control the latter radiosensitivity seemed to exert its effect on the radiosensitivity measured by the callus growth. When calli initiated from seeds were irradiated three days after inoculation on agar medium, the value of D50 for callus growth decreased markedly from 44 kR in seed irradiation to 5 kR in callus irradiation for the covered variety, while the change in the value of D50 was slight, changing from 7 to 3 kR for the naked variety. The difference in the value of D50 was not large, but still significant (Figs. 4 a, 4 b). The relationship between the value of D50 for seedling growth in the case of seed and seedling irradiation and that of D50 for callus growth after callus irradiation varied considerably with the varieties. (author)

  1. Effect Of Gamma Ray Irradiation On Streptococcus Agalactiae Growth For Vaccine Agent Of Mastitis Disease In Dairy Cattle

    International Nuclear Information System (INIS)

    A study has been conducted to determine the effect of gamma ray irradiation to attenuate infectivity of S. agalactiae as dominant bacteria causing mastitis in dairy cattle. The aim of the study is obtaining optimum irradiation dosage to provide radio vaccine for mastitis. S. agalactiae isolate bacteria of which has reach the mid log-phase was cultured and divided into 6 treatment groups of irradiation doses, i.e. 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Following irradiation, bacteria were then cultured in BHI agar media for colony counting to determine the LD50, resulting 7.5x108; 5.0x107; 7.0x106; 9.5x105; 1.5x104; and 3.5x103 cell/ml, respectively. Result of this study shows the higher irradiation doses the lower number of bacteria per ml, and LD50, which found to be under 0.2 kGy of irradiation dose

  2. Reoxygenation and recovery phenomena after potentially lethal damage of tumor cells EMT6 following thermal and epithermal neutron irradiation. Comparison with those after gamma-ray irradiation

    International Nuclear Information System (INIS)

    A lot of hypoxic cells exist usually in solid tumor. The humor cells, which need commonly oxygen for breeding, are killed selectively by irradiation, but almost all of the hypoxic cells survive. Fraction of hypoxic cell in the solid tumor after the irradiation increases relatively. The fraction of the survived hypoxic cell, however, decreases with time. Radiation sensitivity of the solid tumor increases again as a whole, Recovery phenomena after the potentially lethal damage (PLD) are recognized in normal culture cells, also. The reoxygenation in the tumor cells is considered as a relatively large recovery phenomena after the PLD. Tumor cells EMT6, which have chronically a large hypoxic fraction, are irradiated for investigating of the reoxygenation and the recovery phenomena by thermal, epithermal neutron and Co-60 gamma-ray in the heavy water neutron irradiation facility of Kyoto University Research Reactor (KUR). Absorbed doses of Balb/c female mice injected the EMT6 tumor cells are 15 Gy for thermal neutron, 27 Gy for epithermal neutron, and 15 Gy for gamma-ray, respectively. Surviving fraction and hypoxic fraction of the EMT6 tumor cells after the irradiation are determined by colony formation ratio. LET dependency of the recovery phenomena, however, is not recognized in the experiments. Reoxygenation phenomena caused by thermal and epithermal neutron irradiation have a tendency of more rapid than that by gamma-irradiation. (M. Suetake)

  3. The methodology study of time accelerated irradiation of elastomers

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Masayuki [Advanced Research Institute for Science and Engineering, Waseda University 3-4-1 Ookubo, Shinjuku-Ku, Tokyo 169-8555 (Japan)]. E-mail: masayuki@kurenai.waseda.jp

    2005-07-01

    The article studied the methods how to shorten the irradiation time by increasing dose rate without changing the relationship between dose versus properties of degraded samples. The samples used were nine kinds of EPDM which have different compounding formula. The different dose of Co-{gamma} ray was exposed to the samples. The maximum dose was 2MGy. The reference condition to be compared with two short time test conditions is irradiation of 0.33kGy/h at room temperature. Two methods shown below were studied as the time-accelerate irradiation conditions.(1)Irradiation of 4.2kGy/h in 0.5MPa oxygen at room temperature. (2)Irradiation of 5.0kGy/h in air at 70{sup o}C. After irradiation the mechanical properties of samples were measured at room temperature. The changes in 100% modulus suggest that irradiation in 0.5MPa oxygen increases slightly scission reaction and irradiation at 70{sup o}C increases slightly crosslinking, compared with the results obtained under low dose rate irradiation (the reference condition). The deviation was mostly in +/-0.25 for 100% modulus and was +/-0.5 for ultimate elongation throughout the all doses, where the value obtained at the reference condition referred to as 1.0. Thus, it was found out that two methods mentioned above are available as time accelerated irradiation conditions.

  4. Selection and characterization of tomato plants for osmotic stress tolerance derived from a gamma ray irradiation

    International Nuclear Information System (INIS)

    The present study has been performed to select the osmotic tolerant lines using polyethylene glycol (PEG 6000)through an in vitro and in vivo mutagensis with a gamma-ray. During the screening, we selected three mutant lines that seemed to confer elevated osmotic tolerance in high concentrations of PEG 6000. Fruits of these mutants (Os-HK101, Os-HK102 and Os-HK103) were those of the wild type. Also the chlorophyll contents were few decreased more in the three mutant lines than the WT plants. Our results suggest that the Os-HK101 is characterized as osmotic stress tolerance considering the sugar concentration and lycopine content. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in sugar or functional chemicals from the selected osmotic resistant lines

  5. The response of mouse jejunal crypt cells to Cs-137 gamma rays and Cf-252 neutron irradiation

    International Nuclear Information System (INIS)

    Male CD2F1/HAP mice were exposed to similar doses from Cs-137 and Cf-252 linear source arrays using a ferris wheel irradiator. The Cs-137 ?-ray dose rate was 87.2 cGy/hr as determined by TLD dosimetry. A paired ionization chamber measurement technique was utilized to evaluate the Cf-252 dose rate; i.e. 14.4 cGy/hr neutron and 6.5 cGy/hr gamma rays (n/? ratio = 2.22). Jejunal crypt scoring criteria followed those established by Withers and Elkind. These experiments show that RBE in small bowel was high using microcolony assay. Analysis of crypt survival curves yielded a RBE for Cf-252 neutrons of approximately 6.0 for small bowel in agreement with data reported by Withers and Elkind. (Auth.)

  6. Fabrication and characterization of monodisperse zinc sulfide hollow spheres by gamma-ray irradiation using PSMA spheres as templates

    Science.gov (United States)

    Zhao, Yongbin; Chen, Tiantian; Zou, Jianhua; Shi, Wenfang

    2005-03-01

    The submicrometer monodisperse zinc sulfide (ZnS) hollow spheres were synthesized by gamma-ray irradiation at room temperature, using monodisperse poly (styrene-methyl methacrylate-acrylic acid) (PSMA) latex spheres as the templates. X-ray diffraction (XRD) spectroscopy, transmission electron microscopy, thermogravimetric analysis, and UV-vis spectroscopy were used to characterize these nanoparticles, indicating the formation of core-shell colloidal spheres, as well as hollow spheres. The TEM study for the ZnS-coated PSMA core-shell particles has revealed the uniform coating of ZnS on the PSMA core surface as a thin layer. The obtained ZnS hollow spheres are uniform having a diameter range of 365-375 nm, and wall thickness range of 25-35 nm.

  7. Assessment of differences between X and gamma rays in order to validate a new generation of irradiators for insect sterilization

    Energy Technology Data Exchange (ETDEWEB)

    Mastrangelo, Thiago; Walder, Julio M.M., E-mail: piaui@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil); Parker, Andrew G.; Jessup, Andrew; Orozco-Davila, Dina; Islam, Amirul; Dammalage, Thilakasiri, E-mail: A.Jessup@iaea.or [Joint FAO/IAEA-UN A-2444, Seibersdorf (Austria). Insect Pest Control Subprogramme; Pereira, Rui, E-mail: R.Cardoso-Pereira@iaea.or [Joint FAO/IAEA-UN, Vienna (Austria). Insect Pest Control Subprogramme

    2009-07-01

    Recent fears of terrorism provoked an increase in delays and denials of transboundary shipments of radioisotopes. This represents a serious constraint to sterile insect technique (SIT) programs around the world as they rely on the use of ionizing energy from radioisotopes for insect sterilization. In order to validate a novel Xray irradiator, a series of studies on Ceratitis capitata (Wiedemann) and Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) were carried out, comparing the relative biological effectiveness (RBE) between X-rays and traditional gamma radiation from {sup 60}Co. Male C. capitata pupae and pupae of both sexes of A. fraterculus, both 24 to 48 h before adult emergence, were irradiated with doses ranging from 15 to 120 Gy and 10 to 70 Gy respectively. Estimated mean doses of 91.2 Gy of X and 124.9 Gy of gamma radiation induced 99% sterility in C. capitata males. Irradiated A. fraterculus were 99% sterile at about 40-60 Gy for both radiation treatments. Standard quality control parameters were not significantly affected by the two types of radiation. There were no significant differences between X and gamma radiation regarding mating indices. The RBE did not differ significantly between the tested X and gamma radiation, and X-rays are as biologically effective for SIT purposes as gamma rays are. This work confirms the suitability of this new generation of X-ray irradiators for pest control programs in UN Member States. (author)

  8. Effects of gamma-rays irradiation in seed of mungbean (vigna radiata (L.) wilczek) composition of media on shoot regeneration of explants from node of cotyledon

    International Nuclear Information System (INIS)

    Study the effects of gamma-rays irradiation and composition and media on shoot regeneration of explants from node of cotyledon of mungbean. Wallet variety have been conducted. The explants derived of irradiated seeds of 10-20 Gy of gamma rays were planted in the 0.7% agar solution. One day after planting in the agar media the embryo axis of germinate seed were removed and the node of cotyledon were cultured in the regeneration media as examples. The results shown that shoot regeneration was influenced by media composition and the doses of gamma rays irradiation in seed. In the MURASHIGE and SKOOG medium which contain of BAP or 2-iP or Kinetin with 3 ppm concentrate respectively the explants could produced 100% of shoots. However, the highest. number of produced shoot (3 shoots) was showed in the medium which contained of BAP. The medium with I ppm concentrate od BAP could produced 100% shoot regeneration and the maximum number of shoots (4 shoots) per explant was showed in with 5 ppm. concentrate of BAP. The effectivity off BAP for shoot regeneration by enrichment of 12 ppm Ag2SO4 in the media. Irradiation of 10-20 Gy gamma rays on seeds of mungbean walet variety could improved shoot regeneration of explants from node cotyledon. (author)

  9. Radioprotection by dipyridamole. Effects on lipid peroxidation in mouse liver after whole-body X-ray and 60Co gamma-ray irradiation

    International Nuclear Information System (INIS)

    To investigate the mechanism of the radioprotective effect of dipyridamole, the lipid peroxide content in mouse liver irradiated by X-ray and 60Co gamma-ray were measured both before and after injection of dipyridamole. The lipid peroxide content was significantly increased in a time-related manner after whole-body irradiation, and the increase depended on the dose of irradiation. There was no significant difference on biological effects between X-ray and 60Co gamma-ray. Dipyridamole given before irradiation significantly inhibited the lipid peroxide increase by whole-body irradiation. The results suggest that inhibition of lipid-peroxidation is a possible factor in the radioprotective effect of dipyridamole. (author)

  10. Culture competency and regeneration capacity of rice (oryza sativa) embryogenic callus after irradiation with 60Co gamma rays

    International Nuclear Information System (INIS)

    The aims of this investigation are to prove the applying of a combination consequence, in vitro somatic embryogenesis induction and irradiation. Three main point were focused. callus formation from irradiated mature embryos, effect of gamma radiation on the growth of embryogenic and the interaction between gamma rays effects and embryogenic calli sizes on regeneration rate. Callus size was classified in this study in three groups. The first white color (> 1.0 mm), less than normal size. The second (1-2 mm ) just reached the normal size, yellowish green color, from which fully regenerated plants were mainly derived and usually produced multiple shoots. The third group was more than normal (5 mm ) in size, yellow green to light green in color, these larger Calli did not regenerate but became rhizogenic and necrotic. The relationship between the larger callus size and plant regeneration ability could be due to that the large calluses are old, with lesser cellular activity. The highest callus induction rate from irradiated mature embryos was found at 20-40 Gy, also higher than non-irradiated embryos. Higher doses of gamma irradiation on callus induction effected a poor response, mature embryos exposited to 60 Gy and non-irradiated callus achieved the lowest callus induction. Callus forming roots ( % rhizogenic callus) was not significantly differed by increased radiation dosage. An increase in callus fresh and dry weight was materialized by an increase in dose from 20-40 Gy than non-irradiated by a decrease in callus and dry weight at 60 Gy. When embryogenic callus grew, green spots began to differentiate and green shoots started to develop respectively

  11. New rice variety, DT38 selected successfully by gamma rays irradiation

    International Nuclear Information System (INIS)

    Mutation breeding has been applied successfully for crop breeding in the world generally and in Vietnam particularly. In many cases, mutagenesis treatment seems to be more efficient than other traditional methods because of this method can create changing only one or two characters but the remains are intact. Under supporting from IAEA/VIE/5/014 and Vietnam Atomic Energy Commission, we carried out scientific research project 'Improvement of Khangdan 18 by induced mutagenesis treatment on dry seed with gamma rays'. The main objective of the project is through mutagenesis treatment to maintain promising characters at the same time to repair some disadvantage characters of the original rice variety, Khangdan 18. New mutant rice variety DT38 has been released, which is prominent to Khangdan 18 such as: higher grain yield, non lodging, good resistance to some main pests and diseases. DT38 has been producing in some provinces in the north and center of Vietnam. The average yielding of DT38 is higher than that of the origin Khangdan 18 about 10%, event in some locations is 15%. October 2007, DT38 has been officially certified as a new mutant variety by the Ministry of Agriculture and Rural Development, Vietnam. Up to now, DT38 displaying in agricultural variety structure in 8 provinces as Hanam, Hatay, Bacninh, Thaibinh, Vinhphuc, Hungyen, Haiduong, Nghean. (author)

  12. Induction of mutant resistant to alternaria blotch of apple by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Apple cultivars resistant to Alternaria blotch disease have been produced by cross-breeding, but it is difficult to produce resistance by crossing without changing the properties of cultivar because the gene composition of the cultivar tree is almost heterozygous. This study aimed to investigate the resistant mutation in Alternaria blotch susceptible and semiresistant cultivars. The resistance to Alternaria blotch pathogen or AM toxin is classified into the following three groups: 1) highly sensitive group including Indo, Redgold and Starking delicious, 2) semi-resistant group including Fuji, Orin and Golden delicious and 3) resistant group including Gala and Tsugaru. After gamma ray exposure of 80 Gy (at 5 Gy/hour), AM-toxin insensitive clones were selected in the VM6 generation. These selected mutants could be rooted and habituated under field conditions. The degree of disease resistance was assessed by AM toxin treatment and Alternaria blotch fungi spore inoculation test. The leaves of these mutants were changed to variegated at high temperature, suggesting that some mutation related to chloroplast might have occurred. Alternaria blotch resistant strains could be produced by exposing to γray and selecting with AM toxin in shoot-tip culture system, but the functional effects of the AM toxin in Alternaria blotch and also the mechanism in the mutant lines were still unclear. (M.N.)

  13. Modification of morphological traits of common beans through gamma-ray irradiation: analysis of three consecutive generations

    International Nuclear Information System (INIS)

    The objective of this investigation were to study the effects of different levels of gamma-rays on some morphological characteristics of a nearly-white seed coat color bean (Phaseolus vulgaris L.) cultivar, and to determine the radiation level which would generate the greatest genetic variability. Breeder seeds of EMGOPA 201 - Ouro cv, a beige seed coat color cultivar, were submitted to gamma-ray irradiation (60 Co). Treatments consisted of eight levels of radiation: 0,10, 15, 20, 25, 30, 35 and 40 Krad. The experimental design was a randomized complete block with four replications. In the field, plots consisted of 100 seeds. The following data were collected: percent germination, plant height, final stand, plant yield and yield components, number of chlorotic and albino mutants, leaf mutants, growth habit alterations, earliness, seed coat brightness, halo color, seed size and format. Among traits greatest variations were observed seed morphology. Seed coat color varied from completely white to a dark-brownish color. Halo color was also modified from yellow (normal) to pink. Brightness of seeds varied from opaque to bright. Seed varied from squared to rounded, and from very small to large. treatments with 20 and 25 Krad generated the greatest variability for several morphological traits from the M1 to M3 generations, a dosage equivalent to the LD50 observed in the M1 generation. Traits such as percent germination, plant height and some yield components were highly and negatively affected by increasing levels of radiation. Modification of yield components as well as many unusual characteristics with late onset were observed in advanced generations, suggesting that late selection would also be useful. (author)

  14. GAS EVOLUTION FROM INSULATING MATERIALS FOR SUPERCONDUCTING COIL OF ITER BY GAMMA RAY IRRADIATION AT LIQUID NITROGEN TEMPERATURE

    International Nuclear Information System (INIS)

    A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM)

  15. Gas Evolution from Insulating Materials for Superconducting Coil of Iter by Gamma Ray Irradiation at Liquid Nitrogen Temperature

    Science.gov (United States)

    Idesaki, A.; Koizumi, N.; Sugimoto, M.; Morishita, N.; Ohshima, T.; Okuno, K.

    2008-03-01

    A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM).

  16. Gamma-ray irradiation effects of poly(ethylene-2, 6-naphthalate) and poly(ethylene-terephthalate)

    International Nuclear Information System (INIS)

    The irradiation effects and radiation resistances of poly(ethylene-2, 6-naphthalate) (PEN) and poly(ethylene-terephthalate)(PET) were investigated by the analyses of evolved gases, crosslinking and chain scission, and physical properties of thermal behavior and tensile strength after irradiation by gamma-rays under vacuum and in oxygen atmosphere. The evolved gases in both PEN and PET were mainly CO2 and small amounts of H2, CH4, and CO. The G-values of CO2 were 0.004 for PEN and 0.07 for PET by irradiation under vacuum, and were 0.26 for PEN and 0.17 for PET in oxygen. In the case of irradiation without oxidation, the crosslinking proceeded mainly for PEN, but the chain scission was the main reaction for PET. In the case of oxidative irradiation, the chain scission proceeded and no cross-linking was observed for both PEN and PET. The change of mechanical properties of PEN film irradiated under vacuum was very small by comparing with PET. The radiation resistances of PEN and PET were evaluated to be 12 MGy for PEN and 2 MGy for PET in non-oxidative conditions, and were 4.5 MGy for PEN and 1.4 MGy for PET in oxidation conditions by the measurements of tensile testing. The reason of high radiation resistance of PEN was thought that PEN molecules have a large resonance energy of napthalene in the polymer chain, and have higher probability of crosslinking comparing with PET molecules due to the molecular conformation such as crystalline structure. (author)

  17. Modification of surface properties of silica-alumina by irradiation with gamma-rays

    International Nuclear Information System (INIS)

    Coprecipitated silica-alumina gel was prepared to contain 11.8 mol.% alumina. The gel was calcined at 523, 673, 823, 973 and 1173 K. The calcination products were irradiated by ?-rays (15-75 Mrad). Nitrogen adsorption at 77 K, water vapour adsorption at 303 K, pyridine chemisorption at 423 K were measured for non-irradiated and ? irradiated silica-alumina samples. The dehydration of isopropanol was measured at 553 K and at a carrier gas flow rate = 25 ml/min. ''gamma-Irradiation (30-75 Mrad) caused appreciable changes in textural properties of silica-alumina. The extents of these changes depend on the irradiation dose and on the pre-calcination temperature. Irradiation with ?-rays decreased the surface acid density and consequently the activity of the irradiated sample towards acid catalyzed reactions decreased. (author)

  18. Individual variability in the yield of chromosomal aberrations after low dose gamma-ray irradiation

    International Nuclear Information System (INIS)

    Full text: Factors such as DNA repair, chromatin structure, cell cycle control and apoptosis can modify the response of mammalian cells to ionising radiation. Consequently, genetic differences underlying these phenomena may affect individual susceptibility to ionising radiation. In the present study interindividual differences in dose response of chromosomal aberrations at low doses of gamma-rays were examined. Peripheral lymphocytes from ten healthy males were isolated from a sample of whole blood. Doses of 0, 0.1, 0.25, 0.5, 0.75 and 1.0 Gy at a dose rate of 0.8 Gy/min were given using a 60Co source. The cells were incubated at +370C for 48 hours, the last 4 hours in the presence of 0.2 μg/ml Colcemid. The cells were treated with hypotonic solution (0.075 M KCl) and fixed in methanol - acetic acid (3:1). A cocktail of biotin-labelled whole-chromosome probes for chromosomes 1, 2 and 4 and a digoxigenin-labelled pan-centromeric probe were used. Detection and amplification of the chromosome cocktail and the centromere probe were performed simultaneously by three layers of antibodies: 1) avidin-FITC and anti-digoxigenin, 2) biotin-labelled anti-avidin and AMCA anti-mouse, 3) avidin-FITC and AMCA anti-rat. Translocations, dicentrics, acentics, insertions and painted ring chromosomes were scored. The observed frequencies of painted translocations and dicentrics were converted into genomic frequencies by the formula established by Lucas et al., and using the lengths of chromosomes 1, 2 and 4 given by Morton. The results will be described in detail and the individual variability will be discussed. (author)

  19. measurement of absorbed dose in mix-dp phantom irradiated by x and gamma rays

    International Nuclear Information System (INIS)

    It has been done of x-rays dan gamma rays absorbed dose measurement of mix-dp phantom of 70 kVp.90kvp and 110 kvp x rays kxo-12 medical exposure and cobalt-60 gamma (50 ci) by UD-170A BeO-TLD. Ionization chamber 12 cc NIRS-R2 as reference dosemeter, which was calibrated on primer dosemeter. In X-rays energy used, it was done of absorbed dose measurement on Mix-Dp phantom surface and depth (d= 10cm) beam field area 10 x 10 cm, focus distance (FSD), s=80 cm dose measurement of 90 kvp X-rays on Mix-Dp phantom surface, depth and scattering (d=15 cm) beam field area 12 x 12 cm, focus distance (FSD),s=79 cm and measurement of absorbed dose Co-60 gamma: 5 R, 10R, 20 R, 30R, 40R and 50R by dose rate 0.434 R/min. It was shown that in clinical, effective energy range of X-rays relative lower than dose range Co-60 gamma. BeO-TLD characteristic on energy dependence is low based on TI sensitivity 1.3 for energy below 100 keV. Relation between absorbed dose and TL response to 90 kVp X-rays shown that rperm=0.990, r ber=0.995 and r sact=0.962. In measurement of Co-60 gamma absorbed dose by BeO-TLD shown TI sensitivity decrease 0.900. The result still needed corrections to achieve optimum measurement of absorbed dose X-rays and gamma by UD-170A BeO-TLD, which were performed optimum fading time and anealling temperature

  20. Detection of DNA damage in cultured cells induced by the potentiating effects of low-dose gamma-ray irradiation by nick translation

    International Nuclear Information System (INIS)

    When mouse L-5178Y cells were irradiated either at room temperature or during low temperature treatment, irradiation effects could be detected by nick translation if cells were incubated at 37oC. The doses of gamma-ray capable of producing detectable nicks were found to be 0.5-1.0 Gy for gamma-ray irradiation at room temperature or 0.1-2.0 Gy for that at low temperature , which is considerably lower than the conventional limits of detection. A damage to DNA was induced by maintaining L-5178Y cells at 0oc for several hours then incubating at 37oC. The delay in repair of low temperature-induced damage was demonstrated in the irradiated cells during the low temperature treatment. (author). 17 refs., 4 figs

  1. Change in microflora of sewage sludge by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Total bacteria of activated dewatered sludge cake of Takasaki city which amounted to 2 x 109 per gram diminished rapidly with the radiation dose, but slowly after 0.5 Mrad, and 103 per gram survived even after 10 Mrad irradiation. However, coliforms which amounted to 8 x 107 per gram were inactivated below 0.5 Mrad irradiation. The predominant bacteria in non-irradiated sludge were Pseudomonas cepacia and it mainly survived up to 2 Mrad, but Bacillus were predominant at 0.5 to 0.7 Mrad irradiation. The main residual flora from 2 to 5 Mrad was composed of Pseudomonas soranacearum, P. cepacia and P. delafieldii, and the main residual flora in more than 5 Mrad irradiated sludge was P. flava. These typical strains of Pseudomonas in phosphate buffer were radiation sensitive, and their D10 values were from 0.005 to 0.021 Mrad under aerobic irradiation conditions. (author)

  2. Effect of gamma-ray irradiation on the unloaded animal model

    Science.gov (United States)

    Choi, Jong-Il; Yoon, Min-Chul; Sung, Nak-Yoon; Kim, Jae-Hun; Jong Lee, Yun; Lee, Ki-Soo; Choi, In-Ho; Nam, Gung Uk; Lee, Ju-Woon

    During the space flight, human beings encountered the extreme conditions such as the cosmic ray irradiation and microgravity. There have been developed the animal models to simulate the microgravity condition in laboratory, but no study was carried out to investigate the combined effect of microgravity and exposure to irradiation. In this study, it was examined the effect of gamma irradiation on the suspension model. Rats were divided into four groups, Group I was loaded and not exposed to gamma irradiation, Group 2 was unloaded and not exposed, Group 3 was loaded and exposed to gamma irradiation at the dose of 50 mSV, and Group 4 was unloaded and exposed to gamma irradiation at the same dose. It was measured body, muscles and tissues weights and the biological analysis and the hematological response in blood samples were conducted. Anti-gravity tissue weight was only changed between loading and un-loading condition. However, there was no difference between irradiation exposed and not exposed unloaded groups. To know the difference of protein expression in anti-gravity tissues, 2 dimensional electrophoresis was performed. It has been found that the expression levels of several proteins were different by unloading condition and by irradiation exposed condition, respectively. These results provided the information on the combined effect of irradiation and microgravity to simulate space flight, and could be useful to search the candidate material for the countermeasure against space environment.

  3. Low temperature gamma ray irradiation effects on polymer materials (4)-gas analysis of GFRP and CFRP

    International Nuclear Information System (INIS)

    Gas analysis was carried out at RT after gamma-irradiation at room temperature and 77K for glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) having the same epoxy resin matrix. Gas yield from CFRP was less than that from GFRP at RT, but comparable at 77 K. The yields of CO and CO2 showed a large dependence on the irradiation temperature, i.e. they were much less at 77 K. Radiation resistance of GFRP and CFRP towards 77 K irradiation is expected to be higher than that towards RT irradiation. (author)

  4. Irradiation with low-dose gamma ray enhances tolerance to heat stress in Arabidopsis seedlings.

    Science.gov (United States)

    Zhang, Liang; Zheng, Fengxia; Qi, Wencai; Wang, Tianqi; Ma, Lingyu; Qiu, Zongbo; Li, Jingyuan

    2016-06-01

    Gamma irradiation at low doses can stimulate the tolerance to environmental stress in plants. However, the knowledge regarding the mechanisms underlying the enhanced tolerance induced by low-dose gamma irradiation is far from fully understood. In this study, to investigate the physiological and molecular mechanisms of heat stress alleviated by low-dose gamma irradiation, the Arabidopsis seeds were exposed to a range of doses before subjected to heat treatment. Our results showed that 50-Gy gamma irradiation maximally promoted seedling growth in response to heat stress. The production rate of superoxide radical and contents of hydrogen peroxide and malondialdehyde in the seedlings irradiated with 50-Gy dose under heat stress were significantly lower than those of controls. The activities of antioxidant enzymes, glutathione (GSH) content and proline level in the gamma-irradiated seedlings were significantly increased compared with the controls. Furthermore, transcriptional expression analysis of selected genes revealed that some components related to heat tolerance were stimulated by low-dose gamma irradiation under heat shock. Our results suggest that low-dose gamma irradiation can modulate the physiological responses as well as gene expression related to heat tolerance, thus alleviating the stress damage in Arabidopsis seedlings. PMID:26945467

  5. Gamma-ray spectrometric measurements of fission rate ratios between fresh and burnt fuel following irradiation in a zero-power reactor

    International Nuclear Information System (INIS)

    The gamma-ray activity from short-lived fission products has been measured in fresh and burnt UO2 fuel samples after irradiation in a zero-power reactor. For the first time, short-lived gamma-ray activity from fresh and burnt fuel has been compared and fresh-to-burnt fuel fission rate ratios have been derived. For the measurements, well characterized fresh and burnt fuel samples, with burn-ups up to 46 GWd/t, were irradiated in the zero-power research reactor PROTEUS. Fission rate ratios were derived based on the counting of high-energy gamma-rays above 2200 keV, in order to discriminate against the high intrinsic activity of the burnt fuel. This paper presents the measured fresh-to-burnt fuel fission rate ratios based on the 142La (2542 keV), 89Rb (2570 keV), 138Cs (2640 keV) and 95Y (3576 keV) high-energy gamma-ray lines. Comparisons are made with the results of Monte Carlo modeling of the experimental configuration, carried out using the MCNPX code. The measured fission rate ratios have 1? uncertainties of 1.73.4%. The comparisons with calculated predictions show an agreement within 13?, although there appears to be a slight bias (?3%).

  6. [Induced radioactivity in irradiated foods by X ray or gamma ray].

    Science.gov (United States)

    Miyahara, Makoto

    2007-01-01

    In the course of the archival studies on safety of irradiated foods by the US Army, experimental records conducted by Glass & Smith, and Kruger & Wilson were investigated, based on our experimental experience. Food irradiation by Co-60 or 4 approximately 24MeV X ray can induce small amount of radioactivity in the foods. The principal mechanisms of the nuclear reactions are (gamma, n). The resulting nuclear products found in irradiated target solutions were Ba-135m, Pb-204m, Hg-199m, Ag-107m,Ag-109m, Cd-111m,Cd-113m, Sn-117m, Sn-119m, Sr-87m, Nb-93m, In113m, In-115m, Te-123m, Te-125m, Lu-178m Hf-160m by the (gamma, n) reaction. The total radio-activities in beef, bacon, shrimp, chicken, and green beans were counted at 60 days after irradiation by Cs-137, Co-60, and fuel element. The activities more than background were found in irradiated bacon and beef by Co-60. and activities were found in most foods when foods were irradiated by high energy X ray and the fuel element. The results were understood as the neutron activation by (gamma, n) or (n, gamma) reaction. Therefore, high energy X ray and spent fuel element were not used for food irradiation. As the results of this study Co-60 has been used with small amount of induced radioactivity in food. PMID:18220055

  7. Identification of gamma ray irradiated wheat by electron spin resonance, DNA comet assay and germination test

    International Nuclear Information System (INIS)

    In several countries, there has been an increase in the use of radiation for food processing thus improving the quality and sanitary conditions, inhibiting pathogenic microorganisms, delaying the natural aging process and so extending product lifetime. The need to develop analytical methods to detect these irradiated products is also increasing. The goal of this research was to identify wheat irradiated using three different techniques: Electron spin resonance, DNA comet assay and germination test, for comparison. Wheat variety IAC 289 and husked wheat variety IAC 355 was from Instituto Agronomico de Campinas. Grains were irradiated with a gamma 60Co source (Gammacell 220 GC) in the Centro de Energia Nuclear na Agricultura and in the Instituto de Pesquisas Energeticas e Nucleares. Dose rate used were 1.6 kGy/h and 5.8 kGy/h. Applied doses were 0.0 kGy ; 0.10 kGy ; 0.25 kGy ; 0.50 kGy ; 0.75 kGy ; 1.0 kGy and 2.0 kGy. After irradiation, grains were analyzed over a 6 month period. It is possible to use E8R to identify irradiated husked wheat until 3 weeks after the date of irradiation. Comet assay was a qualitative test that we used to identify irradiated wheat at least 6 months after storage. The germination test make possible the identification and the better criteria was the shoot length. (author)

  8. Effects of gamma-ray irradiation on a cyanate ester/epoxy resin

    International Nuclear Information System (INIS)

    Effects of ?-ray irradiation on a cyanate ester/epoxy resin composed of dicyanate ester of bisphenol A (DCBA) and diglycidyl ether of bisphenol A (DGEBA) were investigated by changes in physicochemical and mechanical properties after the ?-ray irradiation with dose of 100 MGy as maximum at around 40 C under vacuum. After the irradiation, gases of hydrogen, carbon monoxide and carbon dioxide were evolved, glass transition temperature decreased, and flexural strength also decreased. It was concluded that ether linkages bonded to cyanurate, isocyanurate and oxazolidinone structures are mainly decomposed by the irradiation. After 100 MGy irradiation, the flexural strength of DCBA/DGEBA was maintained more than 170 MPa which is 90% of initial value of 195 MPa. Flexural modulus and density slightly increased to the values of 3.9 GPa and 1.211 g/cm3 from initial values of 3.4 GPa and 1.199 g/cm3, respectively. - Highlights: A cyanate ester/epoxy resin was irradiated by ?-rays with dose of 100 MGy in vacuum. Viscoelastic property, structural change and gas evolution were investigated. Ether linkages in the network structure were mainly decomposed by the irradiation. The flexural strength of resin was maintained >170 MPa which is 90% of initial value

  9. Effectiveness of gamma-ray chronic irradiation on in vitro mutagenesis in crops

    International Nuclear Information System (INIS)

    Effects of chronic or acute irradiations were compared using in vitro culture on inducing the mutation in model crops. In chrysanthemum, combined method with irradiation and in vitro culture can solve the problem of chimera formation in induced mutants, and provided 10 times greater mutation frequency than usual plant irradiation. The chronic culture method showed the widest color spectrum, whereas, the acute culture indicated a relatively low mutation rate and a very limited flower color spectrum in chrysanthemum. Flower color mutation of the regenerators could be induced more from petals and buds than from leaves. These facts are supposed that the gene loci fully expressed on floral organs may be unstable for mutation by mutagenesis or culture. It may be likely to control a direction of desired mutation on using explants with specific gene loci activated. In sugarcane, the chronic culture method extended quantitative characteristics of regenerated clonal lines toward not only the negative but positive direction. On the other hand, the acute culture method showed lower quantitative mutation as the irradiation dose rose. In chronic irradiation, regenerated mutant lines in sugarcane indicate generally little decrease in chromosome number and wider variations with relatively less damage. In acute irradiation, regenerated mutant lines show remarkable decrease of chromosome numbers in sugarcane mutant lines as the irradiation dose rose. There is close positive correlation between chromosome number and biomass of each mutant line. The chromosome number estimation is a proper indicator to monitor damage of adopted irradiation methods. Possible reason why the chronic culture methods indicate higher frequency and wider spectrum on mutation is demonstrated. . Problems solved and prospect of chronic irradiation and in vitro techniques are discussed. (Author)

  10. SAXS investigations of structural changes after gamma ray irradiation of potato starch and starch suspensions

    International Nuclear Information System (INIS)

    The products obtained after gamma irradiation with doses 9.1, 18.2, 36.3, 54.5 kGy of native starch and water suspensions of starch were investigated using small-angle X-ray scattering (SAXS). Relations between changes in the scattering curves (diminution of the intensity of the reflection related to distance d?100 A and elevation of scattering curves) connected with destruction of long-range ordering in starch granules, and the conditions of the irradiation process were observed. Iradiation influences the long-range ordering more intensively in cases of native starch as compared with water suspensions of starch irradiated. (orig.)

  11. Low temperature gamma ray irradiation effects on polymer materials (4)-gas analysis of GFRP and CFRP

    Science.gov (United States)

    Kudoh, H.; Kasai, N.; Sasuga, T.; Seguchi, T.

    1996-11-01

    Gas analysis was carried out at RT after gamma-irradiation at room temperature and 77K for glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) having the same epoxy resin matrix. Gas yield from CFRP was less than that from GFRP at RT, but comparable at 77 K. The yields of CO and CO 2 showed a large dependence on the irradiation temperature, i.e. they were much less at 77 K. Radiation resistance of GFRP and CFRP towards 77 K irrdiation is expected to be higher than that towards RT irradiation.

  12. Effects of whole body irradiation of 60Co-gamma ray on vivo primary migration of mesenteric lymph node lymphocytes in mice

    International Nuclear Information System (INIS)

    Using a cell labeling technique with 51Cr, the changes in the in vivo primary migration of mesenteric lymph node (MLN) lymphocytes were investigated in mice after whole body irradiation with 60Co-gamma rays. The results showed that after 0.5 to 4 Gy whole body irradiations with 60Co-gamma rays, there are some marked changes in the primary migration of murine MLN lymphocytes in normal syngeneic recipients. In recipients, an increased content of 51Cr in liver was observed after a 4 Gy irradiation of the donor, but no significant change in the 51Cr content was found in spleen at any dose, and the contents of 51Cr in MLN at 0.5 Gy, in lungs at 1 Gy and in small intestine at 1 Gy were significantly decreased

  13. Dose Response and Optical Properties of Dyed Poly Vinyl Alcohol-Trichloroacetic Acid Polymeric Blends Irradiated with Gamma-Rays

    Directory of Open Access Journals (Sweden)

    Susilawati

    2009-01-01

    Full Text Available Problem statement: The effects of gamma irradiation on optical properties of cresol-red dyed Poly Vinyl Alcohol (PVA blended with Trichloroacetic Acid (TCA for possible use in dosimetry and measurement of radiation dose in gamma rays have been studied using both Raman spectroscopy and UV-Visible spectrophotometer method. Approach: The dosimeters are composed of Poly Vinyl Alcohol (PVA, Trichloroacetic Acid (TCA at various concentrations are 20, 25, 30 and 35%, and acid-base indicator cresol-red dyed. Results: The dosimeters were irradiated to doses up 12 kGy using 60Co gamma ray source at a constant dose rate. The polymeric films undergo color change from purple to yellow due to radiation-induced acid formation. The molecular vibrational spectra were measured using Raman spectroscopy, resulting in a decrease of the Raman intensity inelastic scattering of C-Cl molecular stretching from TCA with increasing dose. The absorption spectra were measured using UV-visible spectrophotometer in the wavelength range 350-700 nm, resulting in a decrease of the absorbance at 575 nm band peak with increasing dose. The dose sensitivity D0 increases with increasing TCA concentration for both scattering and absorption methods. The optical absorption studies show that the direct and indirect optical energy band gaps and optical activation energies are dependent on dose and TCA concentration. Conclusion: The shift in the optical band gap Eg values towards lower energy with radiation dose leads to a shift of the optical activation energy DeltaE value towards the lower energy region with increasing dose. The optical band gap (Eg and the absorption edge decrease with increasing dose attributed to the structural disorder of polymer blends due to dehydrochlorination of trichloroacetic acid with increasing dose. The energy width of the tail of localized state in the forbidden band gap was evaluated using the Urbach-edges method. It was found that the activation energy (DeltaE is less dependent of radiation dose but strongly dependent on concentration of blends.

  14. Behavior of Random Hole Optical Fibers under Gamma Ray Irradiation and Its Potential Use in Radiation Sensing Applications

    Directory of Open Access Journals (Sweden)

    Anbo Wang

    2007-05-01

    Full Text Available Effects of radiation on sensing and data transmission components are of greatinterest in many applications including homeland security, nuclear power generation, andmilitary. A new type of microstructured optical fiber (MOF called the random hole opticalfiber (RHOF has been recently developed. The RHOFs can be made in many differentforms by varying the core size and the size and extent of porosity in the cladding region.The fibers used in this study possessed an outer diameter of 110 μm and a core ofapproximately 20 μm. The fiber structure contains thousands of air holes surrounding thecore with sizes ranging from less than 100 nm to a few μm. We present the first study ofthe behavior of RHOF under gamma irradiation. We also propose, for the first time to ourknowledge, an ionizing radiation sensor system based on scintillation light from ascintillator phosphor embedded within a holey optical fiber structure. The RHOF radiationresponse was compared to normal single mode and multimode commercial fibers(germanium doped core, pure silica cladding and to those of radiation resistant fibers (puresilica core with fluorine doped cladding fibers. The comparison was done by measuringradiation-induced absorption (RIA in all fiber samples at the 1550 nm wavelength window(1545 ± 25 nm. The study was carried out under a high-intensity gamma ray field from a 60Co source (with an exposure rate of 4x104 rad/hr at an Oak Ridge National Laboratory gamma ray irradiation facility. Linear behavior, at dose values less than 106 rad, was observed in all fiber samples except in the pure silica core fluorine doped cladding fiber which showed RIA saturation at 0.01 dB. RHOF samples demonstrated low RIA (0.02 and 0.005 dB compared to standard germanium doped core pure silica cladding (SMF and MMF fibers. Results also showed the possibility of post-fabrication treatment to improve the radiation resistance of the RHOF fibers.

  15. Study on the changes in phyicochemical properties of seafood cooking drips by gamma ray irradiation

    International Nuclear Information System (INIS)

    Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T.thynnus, were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips

  16. Study on the changes in phyicochemical properties of seafood cooking drips by gamma ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong Il; Kim, Yeon Joo; Kim, Jae Hun; Yoon, Yo Han; Song, Beom Seok; Lee, Ju Woon [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Chun, Byung Soo; Ahn, Dong Hyun [Pukyong National University, Busan (Korea, Republic of); Lee, Ju Yeoun [Chonbuk National University, Jeonju (Korea, Republic of)

    2010-03-15

    Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T.thynnus, were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips.

  17. Gamma ray-assisted irradiation of few-layer graphene films: a Raman spectroscopy study

    International Nuclear Information System (INIS)

    This paper represents results of a Raman spectroscopy study of gamma-irradiated few-layer graphene thin films at three different doses: 25, 50 and 110 kGy. Graphene thin films were deposited by the vacuum filtration method and then transferred onto glass substrate. Raman spectroscopy and atomic force microscopy analysis have shown that the average in-plane crystallite size La of graphene thin films varies slightly when an irradiation dose is applied. Raman spectroscopy revealed that gamma irradiation of graphene thin films resulted in slight p-doping of the graphene thin film surface. It was found that during gamma irradiation at a dose of 110 kGy, the graphene sheets merged. As a result, the number of incorporated defects in the graphene structure was reduced (the ID/IG ratio decreased with the increase in the applied dose). (paper)

  18. Structure alteration and immunological properties of 60Co-gamma-rays irradiated bothropstoxin-I

    International Nuclear Information System (INIS)

    In this work, the authors investigated the immunological behavior of bothropstoxin-I (BTHX-1), before and after irradiation process, and also the influence of scavengers substances on protein alterations induced by free radical production. Structural modifications were investigated by SDS-PAGE in reducing or non-reducing conditions. In vitro cytotoxicity assay was performed to test average toxic activities of BTHX-I. BALB/c Isogenic mice were immunized with irradiated or non-irradiated (native) forms of BTHX-I and antibody titers and isotypes were determined by ELISA method. Expression of murine cytokines was analyzed by using expression data obtained by quantitative real-time PCR (qPCR) assays. The results indicate that irradiation of proteins leads to significant structural modifications, and also changes the cytokines profile during immunization process, regarding a suitable approach to new immunogenic production. (author)

  19. Characterization of Amylopectin irradiated by gamma rays using viscosity and radius gyration technique

    International Nuclear Information System (INIS)

    Food irradiation is one of the most applicable methods that have been used in food industry especially to preserve food. Besides preservation of food, irradiation can also reduce microorganism, inhibit budding and others. However, this method can be misused by some irresponsible organization or person such as irradiate the food over the dose limit value. Therefore, the detection method is important to detect any misused in irradiation method. The objective of this research is to identify any changes in the structure of amylopectin by using radius gyration technique. Besides that, the viscosity of the sample is also determined by using Rheometer. The last objective of this research is to find a relationship between radius gyration and irradiation dose can be determined. Amylopectin and cassava powder were the sample in this research. The samples were irradiated in the gamma-cell at 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, and 10.0 kGy doses. 0 kGy were the controlled sample. The sample were made into gel to analysed using Rheometer and Small Angle X-ray Scattering (SAXS). The viscosity of the sample were analysed by using Rheometer while the radius gyration of the sample were analysed by using SAXS. Hence, the result of this experiment is, the viscosity of amylopectin reduces as the doses increases. But, at 10 kGy, the viscosity of the cassava starch was increased significantly. For the SAXS analysis, it is shows that the graph for amylopectin were fluctuates. While, for cassava starch the radius gyration increases with doses. Hence, the rheometer technique is suitable to be develop as a detection method in food irradiation. Further research should be done to improve the detection technique in food irradiation. (author)

  20. Gamma ray irradiated goat milk: comparative sensorial analysis with pasteurized goat milk

    International Nuclear Information System (INIS)

    Goat milk consumption has increased in the last years, due to its better digestibility and for constituting a good alternative to cow milk for intolerant people. Brazil has over 10 millions goats, mainly in the Northeast area. Considering that it is very important to increase the shelf-life for this product, this work was done to test the gamma-radiation as a preservation method, evaluating acceptability by sensorial analysis compared with pasteurized milk. The goat milk was bought in the Animal Production Department/ESALQ/USP, Piracicaba, and irradiated with 3,5 kGy in the Food Irradiation Laboratory/CENA/USP, using a cobalt-60 irradiator, type Gammabeam-650, from Nordion, Canada. After irradiation, the samples were maintained under refrigeration at 5 deg C and submitted to sensorial analysis at 1st, 7th and 15th days by 30 untrained tasters. The results indicated, by Tukey test, a significant preference for the pasteurized milk in comparison to the irradiated one, because a hard caprine flavor was developed by the irradiation. (author)

  1. Structure alteration and immunological properties of {sup 60}Co gamma rays irradiated bothropstoxin-I

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Janaina A.; Yonamine, Camila Myiagui; Caproni, Priscila; Casare, Murilo; Spencer, Patrick Jack; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: janabap@gmail.com; Andrade Junior, Heitor Franco de; Vieira, Daniel Perez; Galisteo Junior, Andres Jimenez [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Instituto de Medicina Tropical de Sao Paulo, SP (Brazil). Lab. de Protozoologia

    2007-07-01

    About 20000 ophidic accidents are registered every year in Brazil. Serum therapy with equine antisera is the only efficient treatment. The venoms employed for immunization are fairly toxic and some venoms present low immunogenicity. Thus, the obtention of modified antigens with lower toxicity and preserved or improved immunogenicity would be useful. These toxins, when submitted to gamma radiation, in aqueous solution, present structural modifications. This occurs due to reactions with the radiolysis products of water. Some scavenger substances, such as NaNO{sub 3} and t-butanol, remove selectively the water radiolysis products. Ionizing radiation has proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, the immune mechanisms involved in recognition, processing and presentation of irradiated antigens are yet unclear. In the present work, we investigated the immunological behavior of bothropstoxin-I (Bthx-1), before and after irradiation, in the presence of selective scavengers. Isogenic mice were immunized with either the native or the irradiated toxin, either with or without scavengers. After three immunizations, serum samples were collected and the antibody titers and isotypes were determined by Enzyme Linked Immuno Sorbent Assay. The antigenic characterization of native and irradiated bothropstoxin-I was performed by Western blot. The detection of expression of murine cytokines (IFN-{gamma} and IL-10) was analyzed by RT-PCR (Reverse Transcriptase-Polymerase Chain Reaction). According to our data, irradiation process has promoted structural modifications in the toxin, characterized by higher molecular weight forms of the protein (aggregates and oligomers). Our data also indicate that irradiated toxins, alone or in the presence of NaNO{sub 3}, an aqueous electron scavenger, were immunogenic and the antibodies elicited by them were able to recognize the native toxin. On the other hand, when the toxin was irradiated in presence of t-butanol, a discrete reduction in antibodies levels was observed, suggesting a role of hydroxyl radicals in the modulation of immune response. Irradiated bothropstoxin-1 elicited antibodies responsive to both toxins forms, as demonstrated by Western blot. The cytokines profiles indicated that IFN-{gamma} mRNA presence appeared to be higher for mice immunized with irradiated toxin, while IL-10 mRNA presence was predominant with the antigen in its native form. These results indicate that irradiation of proteins leads to significant structural modifications, and also to a modulation of the immunological response. (author)

  2. Stage differences in developmental disorders in ICR mouse embryos irradiated with gamma-rays

    International Nuclear Information System (INIS)

    This study was designed to determine precisely the radiosensitive period in the development of ICR mouse embryos during which external malformations and growth retardation tend to occur. Female and male mice were placed together for only three hours to allow fairly precise identification of the time of conception. The pregnant mice were divided into 31 groups, which were irradiated in turn with 1.5 Gy gamma radiation at 6-hour intervals during the period of organogenesis. They were then observed on day 18 of gestation. Items recorded were intrauterine death, external malformations, sex ratio and fetal body weight. Death of the embryo/fetus, especially death in the early period of organogenesis, was most frequent in mice irradiated between days 6.75 and 8.25 of gestation, but there was no statistically significant difference in the frequency of early- and late-period deaths between irradiated and control groups. The types and frequencies of external malformations observed differed according to the exposure period. The most highly sensitive period for each malformation lasted no more than 12 hours. Reduction of fetal body weight was a good indicator of radiation effects, and was observed mostly in the groups irradiated between days 9.75 and 11.00 of gestation. The sex ratio was not affected by the period in which irradiation was performed. (author)

  3. Studies of agregates produced during venom irradiation of Crotalus durissus terrificus with gamma ray

    International Nuclear Information System (INIS)

    Literature data show that 2.0 kGy dose of gamma radiation, generated by 60 Co source, reduces the toxic activity of Crotalus durissus terrificus venon, without altering its immunogenic capacity. When crotoxin, main toxin from crotalic venom, was irradiated with the same dose, toxicity was laos reduced and the immunogenicity was maintained. This fact was attributed to aggregates(compounds with high molecular weight generated during irradiation), that showed no toxicity but were able to induce the antibodies formation against native venom. Crotalus durissus terrificus venom was irradied with 2.0, 3.0, 5.0 and 10.0 kGy doses and submitted to molecular exclusion chromatography, in order to find an efficient dose that produces large amounts of non toxic but still immunogeneic aggregates. After being isolated, the products of irradiation were evaluated for the amount produced, molecular ateration, and toxic and immunogenic activities. The results from different doses irradiated venom were compared with native one, and 2.0 kGg dose was confirmed to be most efficient in the association of toxicity attenuation with maintenance of immunogenicity of the crotalic venom, while other doses, in spite of being efficient in the toxicity attenuation, they were not able to keep the immunogenicity property. So, the dose of 2.0 kGy could be used to immunize animals in order to improve anticrotalic sera production. (author). 14 refs., 6 figs., 4 tabs

  4. Biochemical changes associated with gamma rays irradiation of Phaseolus mungo seeds in roots during juvenile differentiation

    International Nuclear Information System (INIS)

    Seeds of Phaseolus mungo L. cv. Pusa Vaishakhi were irradiated with 5 uc - Cs137 source for 10 minutes and 60 minutes. Control seeds along with irradiated seeds were germinated in distilled water at room temperature (300C) upto 96 hours. Root elongation, dry weights of root and root branches were increased by radiation treatment. Roots were analyzed for ascorbic acid (AA), ascorbigen (ASG), ascorbic acid utilization (AAU), catalase, peroxidase and ascorbic acid free radical peroxidase (AA-FR-peroxidase) activities at 24 hourly interval upto 96 hors of germination. AA content decreased, while ASG content increased under the influence of radiation. Activities of oxidative enzymes were enhanced by radiation treatment. Possible relationship between biochemical changes and stimulation of root growth due to irradiation is discussed. (author)

  5. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    Science.gov (United States)

    Chen, C. Y.; Fu, M. J.; Tsai, C. Y.; Lin, F. H.; Chen, K. Y.

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe3O4 was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered.

  6. Development and characterization of biodegradable polymer blends - PHBV/PCL irradiated with gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Rosario, F. [Faculdade de Tecnologia da Zona Leste (FATEC-ZL), Sao Paulo, SP (Brazil). Centro Paulo Souza; Casarin, S.A.; Agnelli, J.A.M. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Souza Junior, O.F. de [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica

    2010-07-01

    This paper presents the results of a study that aimed to develop PHBV biodegradable polymer blends, in a major concentration with PCL, irradiate the pure polymers and blends in two doses of gamma radiation and to analyze the changes in chemical and mechanical properties. The blends used in this study were from natural biodegradable copolymer poly (hydroxybutyrate-valerate) (PHBV) and synthetic biodegradable polymer poly (caprolactone) (PCL 2201) with low molar mass (2,000 g/mol). Several samples were prepared in a co-rotating twin-screw extruder and afterwards, the tensile specimens were injected for the irradiation treatment with 50 kGy to 100 kGy doses and for the mechanical tests. The characterization of the samples before and after the irradiation treatments was performed through scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and mechanical tensile tests. (author)

  7. The effect of gamma-rays on the hemoglobin of whole-body irradiated mice

    Science.gov (United States)

    Ashry, H. A.; Selim, N. S.; El-Behay, A. Z.

    1994-07-01

    Changes in the UV-visible absorption spectrum of mouse hemoglobin as a result of whole body irradiation were studied. White albino adult mice were exposed to a Cs-137 ?-source at a dose rate of 47.5 Gy/h to different absorbed dose values ranging from 1 to 8 Gy. Blood specimens were taken 24 h after irradiation. The UV-visible absorption spectra of hemoglobin of irradiated and control mice were measured in the wavelength range from 200 to 700 nm. The obtained results showed significant changes in the bands measured at 340 nm, in the Soret band measured at 410 nm, also, the ?- and ?-bands measured at 537 and 572 nm showed significant decrease in intensity with the absorbed dose increase. The absorbance measured at 630 nm showed no significant changes. The radiation effect on the animal hemoglobin was discussed on the basis of the obtained results.

  8. Effect of the irradiation on Salmonella enteretidis var. typhimurium with gamma rays from 60Co

    International Nuclear Information System (INIS)

    The use of ionizinf radiation to the destruction of microrganisms responsible for food deterioration, and productive of feeding toxinfections constitute their usefulness for actually peaceful goals of nuclear energy. The feeding toxinfections are, among us, produced in their most part by Salmonella enteritidis var. typhimurim. One hundred nineteen samples of milk containing about 150.000 bacteria per ml, by means doses ranging from 100 to 1.100 gy, two samples of surviving bacteria were again irradiated by doses up to 2.5000 Gy. The bacteria not previously irradiated were throughly killed by means of doses of 1.100 Gy. Salmonella enteritidis var. typhimurium was inactivated by means of 1.200 and 1.900 Gy doses. It was concluded that 60-Cobalt gamma radiation minimal lethal dose to Salmonella enteritidis var. typhimurium is 1.200 Gy; the re-irradiation to the survivors prompts the forthcoming of more resistant germs. (author)

  9. Chemical and physical change of packaging materials for food by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Recently, foods are often exposed to radiation under packed states with various wrapping materials. In this study, the effects of ?-ray radiation were investigated on the additives in wrapping materials on the market. 10 - 50 kGy ? radiation was irradiated to samples under sealed condition in a glass-ware. Polyethylene bag and wrapping film, polypropylene wrapping film, cup and sheet, and polystyrene cup were used as samples. And the additives in these materials were analyzed by GC/MS to evaluate the radiation effects on them. The irradiation was found to induce rapid degradation of antioxidants, especially, Irgafos 168. Some fatty acid amides used as a lubricant and a plasticizer, DBP were also reduced, but not aliphatic hydrocarbons. However, all polystyrene products used in this study included no additives. The contents of styrene dimer and trimer in those wrapping materials were not changed by ?-irradiation. (M.N.)

  10. Development and characterization of biodegradable polymer blends - PHBV/PCL irradiated with gamma rays

    International Nuclear Information System (INIS)

    This paper presents the results of a study that aimed to develop PHBV biodegradable polymer blends, in a major concentration with PCL, irradiate the pure polymers and blends in two doses of gamma radiation and to analyze the changes in chemical and mechanical properties. The blends used in this study were from natural biodegradable copolymer poly (hydroxybutyrate-valerate) (PHBV) and synthetic biodegradable polymer poly (caprolactone) (PCL 2201) with low molar mass (2,000 g/mol). Several samples were prepared in a co-rotating twin-screw extruder and afterwards, the tensile specimens were injected for the irradiation treatment with 50 kGy to 100 kGy doses and for the mechanical tests. The characterization of the samples before and after the irradiation treatments was performed through scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and mechanical tensile tests. (author)

  11. Characterization of injected linear low density polyethylene (LLDPE) irradiated by gamma-ray

    International Nuclear Information System (INIS)

    The aim of this paper is to investigate of gamma irradiation effects on linear low density polyethylene (LLDPE) injected. Polymers processed by gamma radiation have new physical-chemical and mechanical properties. The ionizing radiation promotes chain scission and creates free radicals which can recombine, providing their annihilation, for crosslinking or branching. The polymer was irradiated with a source of 60Co at doses of 5, 10, 20, 50 or 100 kGy at about 5 kGy s-1 rate, at room temperature. The changes in molecular structure of LLDPE were evaluated using melt flow index, gel fraction, differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR) and thermogravimetry analysis (TG). The results showed that the properties depend on dose irradiation. (author)

  12. Physico chemical and microbiological changes in nopal (Opuntia spp.) irradiated with gamma rays of cobalt 60

    International Nuclear Information System (INIS)

    The objective of this work is to study the physico-chemical and microbiological changes which take place in the nopal (Opuntia spp.) after they have been irradiated and stored at environment and refrigeration temperatures in order to determine the level of irradiation dose more adequate for getting them an increase in the storage life, as well as to determine the physico-chemical changes attributed to the irradiation doses used, comparing the obtained results with those ones of non-irradiated nopal samples, which are considered as control samples. The radiation source used was a GAMMABEAM-651 PT, property of the Nuclear Sciences Institute of UNAM. The nopals studied are of the variety (Milpa Alta, Opuntia ficus) which were cut and packed in polyethylene bags with and without nitrogen. In order to find the adequate dose level it was used a lot of 200 samples which were treated in sets of 10. They were irradiated in doses of 0.5 to 10 kGy at a dose reason of 3.7 kGy/h. The adequate doses for getting an increase in the storage life, where there was not darkness were of 1.5 and 2.0 kGy, allowed doses in the NOM-033-SSA1-1993, it was not found any change in acceptability by flavour, but so in the titled activity values and sugars. The lowest loss of weight was found in the 1.5 kGy dose without nitrogen and the highest in the 2.0 kGy with nitrogen dose. Likewise was determined that with the irradiation treatment in the recommended doses it is diminished the microorganisms growth, obtaining an improvement in the general appearance of the nopals during their storage period. (Author)

  13. Myeloid leukemia in male RFM mice following irradiation with fission spectrum neutrons or gamma rays

    International Nuclear Information System (INIS)

    The induction of myeloid leukemia following fission neutron irradiation was examined over the 0-80 rad dose range. Over this dose range the dose response could be described by the linear regression equation: y = 0.94 + 0.18X. A comparison of these data with data obtained following gamma irradiation from this study and a previous study indicated that the relative biological effectiveness for myeloid leukemia induction was 2.8. These results appear to be compatible with those reported by other investigators

  14. Activity of lysosomal acid phosphatase in the perpheral blood lymphocytes of mice irradiated with gamma rays

    International Nuclear Information System (INIS)

    In the peripheral blood lymphocytes of Albino-Swiss mice after irradiation with 450 r an intracellular increase in the acid phophatase activity was determined with Barka and Anderson's cytochemical method. The increase in the enzyme activity was accompanied by the increase in the absolute count of enzyme-positive lymphocytes exhibiting high activity of the enzyme, i.e. containing more than five enzyme-positive lysosomal granules. The absolute count of cells of diffuse enzymatic reaction type did not increase after irradiation. (author)

  15. Investigation of some physical properties of polypropylene irradiated by gamma rays

    International Nuclear Information System (INIS)

    Pure polypropylene samples were exposed to different of gamma radiation up to 100 kGy in presence of oxygen or nitrogen. Some physical properties were investigated in relation to the radiation dose: melting point, crystallinity, apparent activation energy; tensile strength,; elongation. The data show that the crystallinity decreases at low doses. In addition, the melting point is shifted to lower temperature with increasing the irradiation dose. The apparent activation energy increases with increasing irradiation dose. The tensile strength increases for low doses up to maximum, and after this value it decreases increasing (Authors)

  16. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  17. Work hardening characteristics of gamma-ray irradiated Al-5356 alloy

    International Nuclear Information System (INIS)

    Effects of ?-irradiation and deformation temperatures on the hardening behavior of Al-5356 alloy have been investigated by means of stressstrain measurements. Wire samples irradiated with different doses (ranging from 500 to 2000 kGy) were strained at different deformation temperatures Tw (ranging from 303 to 523 K) and a constant strain rate of 1.510?3 s?1. The effect of ?-irradiation on the work-hardening parameters (WHP): yield stress ?y, fracture stress ?f, total strain ?T and work-hardening coefficient ?p of the given alloy was studied at the applied deformation temperature range. The obtained results showed that ?-irradiation exhibited an increase in the WHP of the given alloy while the increase in its deformation temperature showed a reverse effect. The mean activation energy of the deformation process was calculated using an Arrhenius-type relation, and was found to be ?80 kJ/mole, which is close to that of grain boundary diffusion in aluminum alloys

  18. Work hardening characteristics of gamma-ray irradiated Al-5356 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Saad, G. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Fayek, S.A. [Physics Department, National Center for Radiation Research and Technology, Nasr City, Cairo (Egypt); Fawzy, A. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Soliman, H.N., E-mail: dr_hany.nazmy@yahoo.com [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt); Nassr, E. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)

    2014-06-01

    Effects of ?-irradiation and deformation temperatures on the hardening behavior of Al-5356 alloy have been investigated by means of stressstrain measurements. Wire samples irradiated with different doses (ranging from 500 to 2000 kGy) were strained at different deformation temperatures T{sub w} (ranging from 303 to 523 K) and a constant strain rate of 1.510{sup ?3} s{sup ?1}. The effect of ?-irradiation on the work-hardening parameters (WHP): yield stress ?{sub y}, fracture stress ?{sub f}, total strain ?{sub T} and work-hardening coefficient ?{sub p} of the given alloy was studied at the applied deformation temperature range. The obtained results showed that ?-irradiation exhibited an increase in the WHP of the given alloy while the increase in its deformation temperature showed a reverse effect. The mean activation energy of the deformation process was calculated using an Arrhenius-type relation, and was found to be ?80 kJ/mole, which is close to that of grain boundary diffusion in aluminum alloys.

  19. Gamma ray irradiation induced degradation in ultra-thin silica layers

    International Nuclear Information System (INIS)

    In this paper, the influence of gamma irradiation on the electrical properties of Metal-Oxide-Semiconductor (MOS) with an ultra-thin silica layer N2O nitrided or not is investigated. Mainly electron trapping, defects generation and breakdown during electrical stress are studied. (author)

  20. Defect states in ZnSe single crystals irradiated with gamma rays

    International Nuclear Information System (INIS)

    Defect states in ZnSe single crystals induced by 60Co ?-ray irradiation have been investigated with deep-level transient spectroscopy (DLTS) and optical deep-level transient spectroscopy (ODLTS). 5-MeV-electron-irradiated crystals have also been examined for comparison. With DLTS measurements it is found that two electron traps at Ec - 0.27 eV and Ec - 0.49 eV are newly introduced, and the concentration of an electron trap at Ec - 0.30 eV, which exists in unirradiated ZnSe, is increased by ?-ray or electron irradiation. Two additional electron traps located at Ec - 0.15 eV and Ec - 0.79 eV are also observed, and are unique to the ?-ray and the 5-MeV-electron-irradiated material, respectively. In ODLTS spectra a newly introduced hole trap at Ev+0.71 eV and the increase in the concentration of a trap at Ev+0.19 eV are observed in the ZnSe irradiated with ? ray or 5 MeV electron. It is concluded that the electron trap at Ec-0.30 eV and the hole trap at Ev+0.71 eV are attributed to a Se and Zn vacancy-associated defect in the ZnSe single crystal, respectively. The hole trap at Ev +0.19 eV is tentatively identified as arising from an impurity Se vacancy complex

  1. Selection of mutants resistant to black spot disease by chronic irradiation of gamma-rays in Japanese pear 'Osanijisseiki'

    International Nuclear Information System (INIS)

    'Osanijisseiki', a self-compatible, spontaneous bud sport of the Japanese pear 'Nijisseiki' is an excellent cultivar with a smooth skin. However, this cultivar is susceptible to Japanese pear black spot disease caused by Alternaria alternata Japanese pear pathotype. To obtain resistant mutants from 'Osanijisseiki', nursery plants of 'Osanijisseiki' have been irradiated chronically with gamma-rays in the Gamma Field of the Institute of Radiation Breeding, NAR, MAFF, since 1986. Screening tests using AK toxin, a host-specific toxin produced by A. alternata Japanese pear pathotype, were performed form 1988 to 1993. Four branches of young trees planted at a distance of 40 m from the 60Co source were selected as being resistant mutants in 1991 (IRB 502-13T and IRB 502-14T) and 1993 (IRB 502-17T and IRB 502-18T). Sensitivity of the four resistant mutants to AK-toxin and susceptibility to the pathogen were compared with other of susceptible and resistant cultivars. The results showed that these four mutants possessed intermediate resistance. Furthermore, a mutant, IRB 502-13T, had the same characteristics as the original 'Osanijisseiki', except for the difference in toxin sensitivity. The characteristics of the other mutants, IRB 502 14-T, IRB 502-17T, and IRB 502-18T, care being examined. (author)

  2. Effect of dissolved oxygen on corrosion behavior of stainless steel in gamma ray irradiation environment

    International Nuclear Information System (INIS)

    Experimental data on corrosion behavior of stainless steel in actual BWR primary environment under irradiated field are lacking in literature, because the personnel access and maintenance for the experiment are difficult. The corrosion test loop, which had two test sections set inside and outside of the irradiation test room, was used to do the work successfully. The tests were performed by control of water quality in two typical BWR corrosion environments, namely normal water chemistry (NWC) and hydrogen water chemistry (HWC). Corrosion products released from the main loop construction material, type 316 stainless steel, and corrosion potentials of test coupons, type 304 stainless steel, were measured. And the corrosion oxide films formed on the coupons were characterized. The corrosion behaviors of the austenitic stainless steels were affected by the corrosion environment, which was determined by both of the water chemistry condition, NWC or HWC, and radiolysis of water

  3. Methodology for metrological specification of gamma ray sources produced by irradiation in nuclear reactors

    International Nuclear Information System (INIS)

    A procedure for calculation of self-shielded cross sections in samples with complex geometry by using analytical methods is presented in this paper. The purpose of this procedure is to prepare multigroup self-shielded cross sections for samples that are to be irradiated in thermal nuclear reactors. As an example of the application, the methodology of neutron flux determination in Fe sample, that is used as an x-ray source after irradiation in a thermal nuclear reactor is described. It was chosen to apply this methodology for heavy water reactor RB with high enriched oxide fuel, by using multigroup Monte Carlo KENO V.a code. The obtained results are compared to the results of 'numerical experiment' done by MCNP-4B referent Monte Carlo code with continuous-energy library (author)

  4. Effect of gamma-ray irradiation on some chemical and physical properties of buffalo milk

    International Nuclear Information System (INIS)

    Gamma irradiation of buffalo milk at low dose of 0.5 Mrad has no effect on the acidity and pH. The heat stability of milk was increased while the salt balance of milk and rennet coagulation time were decreased. Effect on α-lact-albumin was very little. A very rear increase was observed in case of phosphorus, citric acid, and Ca + Mg content of milk. (orig.)

  5. Repair of skin damage during fractionated irradiation with gamma rays and low-LET carbon ions

    International Nuclear Information System (INIS)

    In clinical use of carbon-ion beams, a deep-seated tumor is irradiated with a Spread-Out Bragg peak (SOBP) with a high-linear energy transfer (LET) feature, whereas surface skin is irradiated with an entrance plateau, the LET of which is lower than that of the peak. The repair kinetics of murine skin damage caused by an entrance plateau of carbon ions was compared with that caused by photons using a scheme of daily fractionated doses followed by a top-up dose. Right hind legs received local irradiations with either 20 keV/?m carbon ions or ? rays. The skin reaction of the irradiated legs was scored every other day up to Day 35 using a scoring scale that consisted of 10 steps, ranging from 0.5 to 5.0. An isoeffect dose to produce a skin reaction score of 3.0 was used to obtain a total dose and a top-up dose for each fractionation. Dependence on a preceding dose and on the time interval of a top-up dose was examined using ? rays. For fractionated ? rays, the total dose linearly increased while the top-up dose linearly decreased with an increase in the number of fractions. The magnitude of damage repair depended on the size of dose per fraction, and was larger for 5.2 Gy than 12.5 Gy. The total dose of carbon ions with 5.2 Gy per fraction did not change till 2 fractions, but abruptly increased at the 3rd fraction. Factors such as rapid repopulation, induced repair and cell cycle synchronization are possible explanations for the abrupt increase. As an abrupt increase/decrease of normal tissue damage could be caused by changing the number of fractions in carbon-ion radiotherapy, we conclude that, unlike photon therapy, skin damage should be carefully studied when the number of fractions is changed in new clinical trials. (author)

  6. Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via {gamma}-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chirachanchai, S.; Kumkrong, A. [The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok (Thailand); Ishida, Hatsuo [Department of Macromolecular Science, Case Western Reserve University, Cleveland, OH (United States)

    2000-03-01

    Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3{alpha}, 12{alpha} -dihydroxy-5{beta}-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by {gamma}-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

  7. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y.; Fu, M.J.; Tsai, C.Y. [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China); Lin, F.H. [Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (R.O.C.) (China); Chen, K.Y., E-mail: chenky@iner.gov.tw [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China)

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe{sub 3}O{sub 4} was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening.

  8. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    International Nuclear Information System (INIS)

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe3O4 was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening

  9. Chemical changes in the chloroform-paraffin system irradiated by 60Co gamma-rays, 1

    International Nuclear Information System (INIS)

    It has been reported that the chloroform-paraffin-dye system have excellent sensitivity for radiation as a solid chemical dosimeter or a phantom. However, the chemical changes in the irradiated system are not examined in detail. In the present study, the effect of paraffin on changes in the above system of a liquid state irradiated by 60Co ?-rays was examined by using various normal paraffin, and the other variable factors on the changes were done. When the chloroform solution and the solution containing 25 per cent of paraffin by volume with 5.0 x 15-5 mol/liter of Methyl Yellow as a dye were irradiated by 2000 R, G values for the formation of hydrogen chloride in the both solutions were 8.4 and 10.8, respectively, and were little affected by the kind of those, from C6 (hexane) to C36 (hexatria-contane). These results suggest that chlorine radical formed by radiolysis of chloroform may react with hydrogen atom from paraffin, thereby increasing the amount of hydrogen chloride. Presence of oxygen increased G value of the chloroform solution from 7.6 to 8.4, but did little that of the solution containing paraffin. (author)

  10. Gamma-ray irradiation characteristics of heat and radiation resistant image fiber

    International Nuclear Information System (INIS)

    A quartz image fiber to be employed in a visual inspection apparatus for core structures and equipments of FBR was examined on radiation resistance characteristics of 2 x 104 R/h, 50 h irradiation of ?-ray at 250 deg C of high temperature atmosphere. Examined quartz image fiber was made of SiO2 core contained in SiO2-F cladding, and three different specimens of A, B and C, the heat processing temperatures of which were standard, low and high, respectively. Ten meters of center part of the specimens bundled in circle were contained in a heating box and irradiated by ?-rays from a 60Co source, and radiation-induced transmission loss was measured by using 0.4 to 0.8 ?m of visible rays. As for the image fiber A, the induced loss increased by 104, 105 and 106 R of total radiation dose and the induced loss increase were 2, 6.5 and 8.5 dB per 10 m at 0.6 ?m, respectively. The induced loss increased remarkably in the wave length region less than 0.5 ?m. As for the effect of heat processing temperature, lower temperature specimen B showed higher loss, and higher temperature specimen C showed lower loss. With the color change of transmitted test pattern, structure defect and color center distribution were speculated in relation to heat processing temperature of the specimens, and the specimen C of higher processing temperature showed a satisfactory result. It was concluded that a suitable image fiber resistant to ?-ray irradiation could be fabricated by regulating a heat processing temperature. (Takagi, S.)

  11. Quality assessment of coffee beans with ESR and gamma-ray irradiation

    International Nuclear Information System (INIS)

    Peroxy radical formation in raw coffee beans of different qualities and origins from all over the world has been studied with electron spin resonance (ESR) analysis. The γ-ray equivalent absorbed dose (ED) which creates the same concentration of radicals is obtained by the additive γ-ray irradiation of the coffee beans. The ED and the cup quality is somewhat inversely related suggesting that the peroxidation of the unsaturated fatty acid is somewhat indicative of the degree of the aromatic decomposition and rancidity. (author)

  12. Gamma-ray irradiation effects on interlaminar tearing strength of epoxy-based FRP

    International Nuclear Information System (INIS)

    The degradation of interlaminar tearing strength induced by ?-ray irradiation in epoxy-based FRP has been investigated. A remarkable decrease in the tearing strength of FRP was observed for higher doses (above 5 MGy). Observation of the fracture surface revealed that a local fracture propagated along the interface between resin and fiber in the lower dose region, and it took place through the resin in the higher dose region. The fracture through the resin it attributed to the degradation of the resin matrix which is typically revealed as voids in the fracture surface. (orig.)

  13. ESR investigations on {gamma}-ray irradiated 3-methyl nylon 3

    Energy Technology Data Exchange (ETDEWEB)

    Catiker, Efkan [Abant Izzet Baysal University, Department of Chemistry, 14280 Bolu (Turkey); Guven, Olgun [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Ozarslan, Ozdemir [Abant Izzet Baysal University, Department of Chemistry, 14280 Bolu (Turkey); Chipara, Mircea [University of Texas Pan American, Department of Physics and Geology, 1201 W. University Drive, Edinburg, TX 78541-2999 (United States)], E-mail: mchipara@utpa.edu

    2008-06-15

    Electron spin resonance spectroscopy investigations on {gamma} irradiated 3-methyl nylon 3 (poly-3-methyl {beta}-alanine) are reported. The resonance spectra (recorded after the irradiation in nitrogen atmosphere has been stopped) have been attributed to the parallel and perpendicular components of a triplet line assigned to the delocalization of the uncoupled electron over an effective nuclear spin 1. It was suggested that this effective spin arises from the fast tunneling/rotation of a proton between two positions. The resonance spectra have been simulated with accuracy by using a simplified spin Hamiltonian and assuming Lorentzian-like resonance line shapes and axial asymmetry of the resonance line due to the trapping of free radicals in randomly oriented crystallites. The time evolution of free radicals in nitrogen atmosphere at room temperature has been analyzed. The decay kinetics of stable free radicals in 3-methyl nylon 3 (under inert atmosphere) has been investigated. It was shown that the radiation-induced radicals in inert atmosphere decay through a unimolecular reaction.

  14. Coloration of fluorophosphate glasses containing fluorescein molecules by heat treatment or gamma ray irradiation

    International Nuclear Information System (INIS)

    The 70SnF230P2O5 glasses containing 25-500 ppm of fluorescein exhibit change in color from light yellow to reddish orange (absorption maximum, ?=500 nm) when heated at 240degC for 120-180 min. The fluorophosphate glasses also change the color from light yellow to reddish brown (?=480 nm) when irradiated with 60Co ?-rays of 5x104 Gy. The P-F stretching mode observed in the Fourier transformed infrared (FT-IR) spectra showed an increase in peak intensity along with the coloration, suggesting a cleavage of the weak chemical bond between fluoride ions (F-) and fluorescein molecules. The coloration is ascribed to change of the molecular structure of fluorescein from non-crystalline to crystalline type. ESR spectra of ?-ray irradiated 70SnF230P2O5 glasses showed a poorly resolved doublet, which was ascribed to a hole-trapped PO3F- center produced by electron scattering: PO3F2- ? PO3F- + e-. (author)

  15. Mechanical Property Of Zeolite-PVA Composite Mixture Irradiated By Gamma Ray Of Co-60

    International Nuclear Information System (INIS)

    Experiment on preparation of zeolite-polyvinyl alcohol composite for absorbance materials have been done by curring using Gamma γ-ray of Co-60. Zeolite with the particles size of 60 mesh was mixed with polyvinyl alcohol (PVA) at the concentration of the mixture were 6,9, and 12% by weight, than they were poured into glass tube (length = 100 mm; diameter = 10 mm) and irradiated at the doses of 10, 20, 30 dan 40 kGy with the dose rate of 7,5 kGy/ hr. Parameters observed were density, compressive strength, and hardness. Experimental results showed that polyvinyl alcohol in the mixture was significant effect to density and compressive strength, where as the irradiation dose was highly significant effect to compressive strength. The effect interaction between dose and polyvinyl alcohol concentration factors had significant effect to density or compressive strength. Almost all samples have pencil hardness of 4 - 5 H, for composite containing 6 % PVA, has pencil hardness of 2 - 3 H

  16. Preparation of hydrogels for atopic dermatitis containing natural herbal extracts by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Atopic dermatitis (AD) is a familial and chronic inflammatory pruritic skin disease that affects a large number of children and adults in industrialized countries. It is known that one of the prominent features of AD and chronic pruritus is partially due to the histamine released from mast cell. In this work, hydrogel patches with natural herbal extracts were prepared by 'freezing and thawing', and a gamma irradiation. It showed eminent healing results as a consequence of long-term moisturizing effects and natural herbal extracts on atopic wounds. Besides its non-toxicity and human harmlessness, it can be easily attached to or detached from the skin without any trace and help patients to feel refreshment when attached. Based on this work, the hydrogel patches we made can be potentially used as an alternative remedy for not only pruritus in AD, but other dermatitis.

  17. Study of physico-chemical processes in yttrium-aluminium garnet under gamma-rays irradiation

    International Nuclear Information System (INIS)

    Ionizing radiation is shown not create any additional latice defects in yttrium-aluminium garnet (YAG) due to their high radiation stability. However, it generates different kinds of electron-hole centres that are stabilized on structural imperfections. In the temperature range 77-300 K three kinds of trapping centres in YAG irradiated by ?-rays have been identified by means of ESR and thermoluminescence technique, namely an electron centre of the first type with g=1.996, stable within the temeperature range 77-150 K, a hole centre of the second type (g=2.016) stable at 300 K. Localization of these centres in the garnet lattice is discussed and their participation in the luminescence processes considered. The influence of the crystallochemical nature of doped ions (Nd, Ce, Cr) on the stabilization of each of these electron-hole centres has also been studied. (author)

  18. Gamma-ray irradiation synthesis of silk fibroin-coated CdS quantum dots

    International Nuclear Information System (INIS)

    Silk fibroin coated CdS quantum dots (SF-CdS QDs) were successfully synthesized in an aqueous system at room temperature under 60Co ?-ray irradiation. The prepared QDs were characterized by transmission electron microscopy (TEM), energy dispersion spectrometry (EDS), Fourier transform infrared spectrometer(FT-IR), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis) and photoluminescence (PL) spectrometry. The synthesized QDs were about 5 nm in diameter with excellent water-solubility. The QDs showed strong visible yellow-green luminescence under UV excitation, at an emission peak of around 538 nm. This method could be conveniently extended to fabricate other nanoparticles coated with silk fibroin. (authors)

  19. Preparation of hydrogels for atopic dermatitis containing natural herbal extracts by gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Youn-Mook; An, Sung-Jun; Kim, Hae-Kyoung [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong Jeongeup-si Jellabuk-do, 580-185 (Korea, Republic of); Kim, Yun-Hye [AMOTECH Co., Ltd., Kimpo-City, Kyungki-do (Korea, Republic of); Youn, Min-Ho; Gwon, Hui-Jeong; Shin, Junhwa [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong Jeongeup-si Jellabuk-do, 580-185 (Korea, Republic of); Nho, Young-Chang [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong Jeongeup-si Jellabuk-do, 580-185 (Korea, Republic of)], E-mail: ycnho@kaeri.re.kr

    2009-07-15

    Atopic dermatitis (AD) is a familial and chronic inflammatory pruritic skin disease that affects a large number of children and adults in industrialized countries. It is known that one of the prominent features of AD and chronic pruritus is partially due to the histamine released from mast cell. In this work, hydrogel patches with natural herbal extracts were prepared by 'freezing and thawing', and a gamma irradiation. It showed eminent healing results as a consequence of long-term moisturizing effects and natural herbal extracts on atopic wounds. Besides its non-toxicity and human harmlessness, it can be easily attached to or detached from the skin without any trace and help patients to feel refreshment when attached. Based on this work, the hydrogel patches we made can be potentially used as an alternative remedy for not only pruritus in AD, but other dermatitis.

  20. Effects of 2.0 Gy of 60Co gamma rays irradiation on rat embryos

    International Nuclear Information System (INIS)

    Pregnant rats of Donryu strain were exposed to a whole-body 60Co ? ray irradiation of a single dose of 2.0 Gy (Dose rate: 0.5 Gy/min) on day 7, 8, 9, 10 or 11 of gestation (sperm day = day 0). The rats were sacrificed on day 18 and the offspring were examined for external and visceral malformations. Malformed embryos occurred between days 7 and 11 with the highest incidence occurring on day 9. Dose with 2.0 Gy increased the rate of resorption or death (52.1 %), in the survivors, caused congenital malformation in a majority of embryos (86.5 %) on day 8 of gestation. There is an increase in malformation (93.3 %) and growth retardation, but no increase in mortality (42.9 %) on day 9 of gestation. Relatively few anomalies resulted from irradiation on day 7 of gestation. The peak day for cardiovascular anomalies occurred on day 9 (88.3 % of all survival embryos) with high levels also occurring on day 8 (86.5 %). Cardiovascular anomalies consisted of VSD, hypoplasia of the pulmonary trunk, coarctation of the aorta, double aortic arch, right aortic arch, riding aorta, complete transposition of the aorta, persistent atrioventricular canal, vascular ring, aberrant right subclavian artery and others. Similar anomalies, but at a lower incidence, were produced by 60Co ? ray at dose levels of 2.0 Gy on day 10 or 11 of gestation. Cases of cleft lip and cleft palate or facial cleft were observed seventeen fetuses on day 9 of gestation (31 %). Exencephaly occurred in nine embryos treated on day 9 (16.1 %) and in one embryos treated on day 10. Tail defects appeared with treatment on day 9 with the latter predominating on day 11. The present study show that maximum resorption (52.1 %) was seen with treatment on day 8 whereas the highest rate of malformation (93.3 %) was observed with treatment on day 9. (J.P.N.)

  1. Control of drug releasing from biodegradable polymer drug delivery system by gamma-ray irradiation

    International Nuclear Information System (INIS)

    In order to introduce the drug to the target organ, we developed a gel to control the drug releasing velocity by response to change of temperature by means of ?-ray irradiation to gelatin-GMA modified dextran mixture aqueous solution. A certain level of molecular weight of drug is necessary. The response to the temperature (change of drug releasing velocity) was affected by the concentration of gelatin and the modification rate of GMA. The Higuchi equation was applied to the releasing of ?-galactosidase from gelatin-dextran gel and the releasing velocity was calculated. The releasing velocity decreased with increasing GMA modification rate at 37degC and 15degC. The releasing velocity of ?-galactosidase decreased with increasing the concentration of gelatin at 15degC, but the velocity increased with increasing the concentration at 37degC. These results indicated that the good drug releasing conditions are obtained by controlling the GMA modification rate and the concentration of gelatin. (S.Y.)

  2. Radio protective effects of calcium channel blockers (Deltiazem) on survival of Saccharomyces cerevisiae cells irradiated with different doses of gamma rays

    International Nuclear Information System (INIS)

    Investigations of radioprotective effects of Deltiazem (as one of the commonly used calcium channel blockers, which is used in the treatment of acute and chronic angina and spasmo angina, in addition to the treatment of different types of essential hypertension) has been carried on Saccharomyces Cerevisiae cells. Cells cultures of the most famous yeast Saccharomyces Cerevisiae (bakers yeast) were irradiated with different doses of gamma rays. Results revealed that the necessary dose of gamma rays that leads to 10% of survived cellular population (D10 value) was about 256 Gy. This irradiation dose was used then in all irradiation experiments on culture of S. Cerevisiae cells in which different concentrations of Deltiazem (55, 110, 165 mg/Kg medium) were added before and after irradiation in order to study the radio protective effect of Deltiazem. Results showed that Deltiazem enhances survival percentage of irradiated S. Cerevisiae cultures in a concentration dependent manner. This study confirmed our previous works, which had demonstrated that Deltiazem protects lethally and supralethally irradiated rats, and enhances survival of pre-irradiated Deltiazem treated animals.(author)

  3. Effects of hydrazine addition and N2 atmosphere on the corrosion of reactor vessel steels in diluted seawater under gamma-rays irradiation

    International Nuclear Information System (INIS)

    Seawater was injected into the reactor cores in the Fukushima Daiichi Nuclear Power Station. Corrosion of primary containment vessel (PCV) steel and reactor pressure vessel (RPV) steel is considered to progress until the molten fuel debris is removed. To evaluate durability of the PCV and RPV steels, corrosion tests were conducted in diluted seawater at 50C under gamma-rays irradiation of dose rates of 4.4 and 0.2 kGy/h. To evaluate the effect of hydrazine (N2H4) as an oxygen scavenger under gamma-rays irradiation, 10 and 100 mg/L N2H4 were added to the diluted seawater. Without addition of N2H4, weight loss in the PCV and RPV steels irradiated with the 0.2 kGy/h dose rate was comparable with those without irradiation and weight loss in the vessel steels irradiated with the 4.4 kGy/h dose rate was higher than those without irradiation. Under irradiation, weight loss in the PCV and RPV steels in diluted seawater containing N2H4 was comparable with that in diluted seawater without N2H4. When gas phase in the flask was replaced with N2, weight loss in the PCV and RPV steels, and O2 and H2O2 concentrations in the diluted seawater decreased. (author)

  4. Thermoluminescence of gamma rays irradiated LiF nanocubes doped with different elements

    International Nuclear Information System (INIS)

    Lithium fluoride (LiF) doped with proper activator is a highly sensitive phosphor, widely used as a dosimeter for ionizing radiations. This work reports on the thermoluminesence (TL) response of LiF nanocubes doped with different impurities. These nanocubes were synthesized by the co-precipitation method and characterized by different techniques. The dopants used in this study are Eu, Tb, Dy, Cu and Ag. The gamma radiation induced TL glow peaks are located in the temperature range 120–125 °C. These samples have different TL sensitivities, where Eu doped one is found to be the most TL sensitive. Further irradiations in the dose range from 10 Gy to 30 kGy were performed to LiF:Eu and the obtained result is explained using a proposed multilevel TL model. According to this model, Eu dopant (in Eu3+ ionic form) could induce shallow and deep electron traps in the host of LiF nanocubes. These traps differ in their response according to the doses. The optimum concentration of Eu ions in LiF host is found to be 0.2 mol%. It is also found that LiF nanocubes are thermally stable in the range of 30–400 °C with a single phase. This property along with the good sensitivity of Eu doped one makes this tissue equivalent nanomaterial a proper candidate for heavy dose measurement like swift heavy ions used in radiotherapy. - Highlights: • Nanocubes of pure and doped LiF were produced by the co-precipitation method. • They were doped with Eu, Tb, Dy, Cu and Ag and studied for their TL response. • The gamma radiation induced TL glow peaks are located in the range 120–125 °C. • The Eu doped one is found to be the most TL sensitive, followed by Tb. • The tissue equivalent LiF:Eu nanocubes might be useful for heavy dose measurement

  5. Late effects of protracted whole-body irradiation of beagles by cobalt-60 gamma rays

    International Nuclear Information System (INIS)

    So that a stronger basis for extrapolation of low-level radiation effects to man can be provided, existing data from small laboratory animals are being supplemented by studies in a longer lived animal, the dog. Beagle dogs are exposed to continuous cobalt-60 irradiation either throughout life or until predetermined total doses are accumulated. The radiation-specific excess-mortality rate and associated causes of death will be related to both dose rate and total dose. The ongoing studies also emphasize the pathogenesis of myelogenous leukemia. At dose rates of 3.75 to 26.25 rads/day, given continuously, responses were consistent, highly dose-rate dependent, and limited primarily to the hematopoietic system. At rates as low as 0.3 rad/day, the hematopoietic system is still the limiting factor for survival, but below 3.75 rads/day present evidence suggests that the responses are independent of dose rate. Longitudinal studies of peripheral blood and bone marrow detected four preclinical phases of myelogenous leukemia. These phases were characterized by standard hematologic end points, ultrastructural features, in vitro cloning assays, and the acute radiation sensitivity of stem cells. Results suggest that an induced error-prone repair mechanism is the basis for the onset of radiation-induced myelogenous leukemia. Interim data from dogs given terminated exposures suggest that the types of tumors and times to death are different from controls but the numbers of tumors are not yet greater than in controls. 26 refs., 12 figs., 5 tabs

  6. A New Green-Kerneled Glutinous Rice Mutant Variety, 'Nogwonchalbyeo' Developed by Gamma Ray Irradiation

    International Nuclear Information System (INIS)

    We bred a new green-kerneled glutinous rice variety that can be cultivated in the whole area of Korea, because only one native green-kerneled glutinous rice cultivar, 'Saengdongchalbyeo', has been cultivated in the southern coastal area due to its late heading. The seeds of 'Saengdongchalbyeo' were irradiated with 200 Gy of gamma ray in 1995. A promising mutant variety, 'Nogwonchalbyeo' ('Wonnong 17') was selected through line selection and regional yield trials. In particular, the new variety revealed at the earlier mid of August compared to that of 'Saengdongchalbyeo', the early of September, and it was considerably tolerant to a field lodging due to its shortened culm length. Also, 'Nogwonchalbyeo' had a higher ripened grain ratio and 1,000 grain weight compared to the original variety. The brown grain yield of the new variety was about 5.40 MT/ha, which was 11.3% higher than that of the original variety, in the regional yield trials at 3 different fields during 2000~2001. The brown and milled grains of the new rice variety contained 20 to 65% higher amount of total amino acids, respectively than that of the original and two checks. For chlorophyll -a, -b and total chlorophyll, the new variety showed nearly two-fold higher than the checks, and for the carotenoid, it had 5.3 - 7.6 times higher amount. These results showed that the new variety can be cultivated as a special green-kerneled glutinous rice with high functional compounds

  7. Low Dose Gamma Irradiation Potentiates Secondary Exposure to Gamma Rays or Protons in Thyroid Tissue Analogs

    Energy Technology Data Exchange (ETDEWEB)

    Green, Lora M

    2006-05-25

    We have utilized our unique bioreactor model to produce three-dimensional thyroid tissue analogs that we believe better represent the effects of radiation in vivo than two-dimensional cultures. Our thyroid model has been characterized at multiple levels, including: cell-cell exchanges (bystander), signal transduction, functional changes and modulation of gene expression. We have significant preliminary data on structural, functional, signal transduction and gene expression responses from acute exposures at high doses (50-1000 rads) of gamma, protons and iron (Green et al., 2001a; 2001b; 2002a; 2002b; 2005). More recently, we used our DOE funding (ending Feb 06) to characterize the pattern of radiation modulated gene expression in rat thyroid tissue analogs using low-dose/low-dose rate radiation, plus/minus acute challenge exposures. Findings from these studies show that the low-dose/low-dose rate priming exposures to radiation invoked changes in gene expression profiles that varied with dose and time. The thyrocytes transitioned to a primed state, so that when the tissue analogs were challenged with an acute exposure to radiation they had a muted response (or an increased resistance) to cytopathological changes relative to un-primed cells. We measured dramatic differences in the primed tissue analogs, showing that our original hypothesis was correct: that low dose gamma irradiation will potentiate the repair/adaptation response to a secondary exposure. Implications from these findings are that risk assessments based on classical in vitro tissue culture assays will overestimate risk, and that low dose rate priming results in a reduced response in gene expression to a secondary challenge exposure, which implies that a priming dose provides enhanced protection to thyroid cells grown as tissue analogs. If we can determine that the effects of radiation on our tissue analogs more closely resemble the effects of radiation in vivo, then we can better estimate the risks and modify assign limits to radiation worker and astronauts. Additionally, confirmation that tissue analogs represent a realistic in vivo response to radiation will allow scientists to perform tissue relevant experiments without the expense of using animals. Confirmation of the in vivo approximation of our model will strengthen our findings from the recent completion of our DOE funding which is the subject of the current proposal.

  8. Radiolysis of ZnSe(Te,O) scintillators at irradiation with nuclear particles and gamma-rays

    International Nuclear Information System (INIS)

    The stoichiometry and radiolytic products of ZnSe(Te,O) crystals before and after irradiation were investigated by instrumental X-ray radiometric and neutron activation analysis of the elemental composition. ZnSe single crystals as-grown, doped with Te, treated in oxygen or a reducing atmosphere and Zn vapours were studied for a comparison. Doping with Te, whose ionic radius is larger than in Se, resulted in the production of V(Se) or V(Zn) structure vacancies. Treatment in oxygen resulted in a partial substitution of Se by smaller O ions giving rise to interstitial Sei or Zni atoms. Treatment in Zn vapour produced extra Zni and V(Se). To generate different kinds of structure defect pairs, the samples were exposed to 60CO 1.25 MeV gamma quanta at doses of 5x105 to 2x109 R at 1000 R/s and temperatures of 80 and 350 K, and separately, to thermal and fast (> 3 MeV) neutron fluxes accompanied by gamma-radiation in a nuclear reactor at fluences of 1016 and 1017 cm-2 at 350 K, and also to 18 MeV protons at a fluence of 1015 cm-2 at 300 K. A comparison between the irradiation with thermal and fast neutrons, charged particles (protons and electrons) and uncharged particles (gamma rays, neutrons) can reveal the difference between the defect production mechanisms and modify the structure. All samples had an as-grown super-stoichiometry of Zn: about 49 % Se and 51 % Zn, while the theoretical stoichiometric ratio in ZnSe is 54.7 % Se and 45.53 % Zn. Such non-stoichiometry makes the surface layer less dense and Zn-enriched. Indeed, analyzing the matter removed from the sample surface, the compound of 70-90 % Zn and 10-30 % Se was determined for different samples. When doping with 0.5 % Te, the impurity was found to be distributed unevenly over the bulk, with two maxima roughly at 0.5 % and 0.25 %. At lower doping levels, Te was distributed evenly. During gamma irradiation, 50-60 % Zn and 40-50 % Se were emitted from the surface. The remaining part of the radiolytic product, removed from the surface mechanically after the irradiation, procedure also had a nearly stoichiometric composition. Moreover, the higher was the irradiation dose, the lower was the loss by radiolysis. When exposed to fast neutrons up to 1016 cm-2, Zn ions were mostly emitted, and at the total flux of 5.4x1016 cm-2, Zn and Se were emitted in the stoichiometric ratio and the scintillating properties deteriorated substantially. The same picture was observed in the layer removed from the irradiated surface. When thermal neutrons were used for irradiation, the behaviour was different and the degradation became significant at a higher fluence (1017 cm-2). Bombardment with high energy protons at a dose of 1015 cm-2 in a vacuum led to permission of super-stoichiometric Zn from the exposed surface and some improvement of the surface and scintillating properties. In conclusion, the non-stoichiometric ion emission and radiolysis of sub-surface layer are responsible for the degradation of the scintillator; a suitable proper radiation treatment, on the other hand, can improve the structure and the characteristics, which is a beneficial positive result of irradiation

  9. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)

    Energy Technology Data Exchange (ETDEWEB)

    Clark, E.

    2013-09-13

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10 ?C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.

  10. Grafting study of polysulfone polymeric membranes by gamma ray irradiation; Estudo da grafitizacao de membranas polimericas a base de polissulfona por irradiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Radiation-induced grafting of styrene poli sulfone films were investigated by simultaneous method in solution using gamma-ray from a radio nuclide {sup 60}Co source. The gamma-ray energy of high intensity induced breaking of chemical bonds leading to free radical formation. The radical start a conventional polymerization sequence comparable with that obtained with a chemical catalyst acting as initiator. The effects of grafting conditions such as irradiation total dose, dose rate and addition of cross linking agent, were studied by means of morphology analysis, thermal degradation and crystallinity. After the grafting reaction, the membranes were submitted to an exhaustive extraction with solvent to remove the polystyrene homopolymer formed. The degree of grafting (DOG) was analyzed by percentage of weight increase. As a result, the reaction always follows the same pattern: DOG increases rapidly initially whilst propagation is the main reaction, then more slowly as termination becomes more frequent. (author)

  11. Cathodic protection for nuclear waste packaging under gamma ray irradiation by using TiO2 coating combined with glass scintillators

    International Nuclear Information System (INIS)

    The photoelectrochemical behaviors of a TiO2 single crystal and TiO2 coating were studied, for the purposes of cathodic protection of stainless steels and Cu via the TiO2 coating combined with glass scintillators under gamma ray irradiation. It was confirmed that a TiO2 coating could protect 304 stainless steel cathodically from crevice corrosion under illumination. A logarithmic relationship between the photopotential of single crystal TiO2 (rutile) and light intensity was found, moreover, the photopotential was found to be least noble when wavelength equals 375 nm. Under illumination by gamma rays combined with the glass scintillators, the electrode potential of single crystal TiO2 was found to shift in the less noble direction by about 200 mV. Therefore, the technique of cathodic protection by TiO2 coating is considered to be applicable to protect the packaging metal from corrosion for a long time

  12. Gamma Ray Bursts

    International Nuclear Information System (INIS)

    I present the observational properties of gamma-ray burst and outline the current theoretical models of these phenomena. I review the main problems in the gamma-ray burst science and sketch the prospects for the future. (author)

  13. Induction, selection and isolation of auxin heterotrophic and auxin-resistant mutants from cultured crown gall cells irradiated with gamma rays

    International Nuclear Information System (INIS)

    Cultured crown gall cells were irradiated with gamma rays to induce mutation in indoleacetic acid biosynthesis. The irradiated cells were plated on a selection medium which contained auxin. Mutant cells adapted to selection media were characterized as auxin-heterotrophic and auxin-resistant cell lines. The auxin-heterotrophic mutants contained little auxin, whereas the auxin-resistant and -autotrophic mutants contained large amounts of auxin even when cultured with 0.3 ppm of 2,4-dichlorophenoxyacetic acid. Each mutant cell line contained as much octopine as its parental cells. The mutation rate was calculated as in the order of 10-8. (author)

  14. Gamma-ray methods

    International Nuclear Information System (INIS)

    Bulk analysis techniques using gamma radiation are described. The methods include gamma-ray induced reactions, selective gamma-ray scattering and methods which rely on natural radioactivity. The gamma-ray resonance scattering technique can be used for the determination of copper and nickel in bulk samples and drill cores. The application of gamma-gamma methods to iron ore analysis is outlined

  15. Gamma-ray astronomy

    OpenAIRE

    Pohl, Martin

    2001-01-01

    This paper summarizes recents results in gamma-ray astronomy, most of which were derived with data from ground-based gamma-ray detectors. Many of the contributions presented at this conference involve multiwavelength studies which combine ground-based gamma-ray measurements with optical data or space-based X-ray and gamma-ray measurements. Besides measurements of the diffuse emission from the Galaxy, observations of blazars, gamma-ray bursts, and supernova remnants this paper also covers theo...

  16. Effect of Irradiation of 60CO Gamma Rays on Growth of Garlic (Allium Sativum L) Plants Cv. Lumbu Hijau at Low Land Area

    International Nuclear Information System (INIS)

    Garlic originally come from the sub tropical area. In Indonesia, garlic is grown generally in high land area with an altitude between 1000 - 1600 m above sea level. Therefore, the area for growing and producing garlic is limited. Besides, genetic variation of garlic is very narrow since garlic belongs to vegetatively propagated crops. An effort for increasing genetic variation of garlic was done by exposing garlic cloves to gamma rays in order to obtain garlic mutant lines adapted to low land area. Garlic cloves were exposed to different doses of gamma rays 0 (untreated) 2, 4, 6, 8 and 10 Gy at the Centre for Research and Development of Isotope and Radiation Technology. Each dose consisted of 150 garlic cloves. Untreated and irradiated garlic cloves were grown at Bandar Buat Experimental Station (50 m above sea level), Padang, West Sumatera. The experiment was arranged in a randomized block design with three replication. The parameter observed were percentage of grown plants and survival harvested plants, plant height, leaf number, chlorophyll content, number of stomata, plant age, number of cloves per bulbs, fresh, dry weight and diameter of bulbs. The result indicated that the dose of gamma rays 6 Gy is an advantage dose for obtaining well adapted garlic mutant lines in the low land area. (author)

  17. Physico-chemical processes in Vertical-Double-Diffused Metal-Oxide-Semiconductor Field Effect Transistors induced by gamma-ray irradiation and post-irradiation annealing

    Directory of Open Access Journals (Sweden)

    Pejovi? Mili? M.

    2015-01-01

    Full Text Available The behavior of commercial power Vertical-Double-Diffused Metal Oxide Semiconductor Field Effect Transistors (VDMOSFETs during gamma-ray irradiation and subsequent annealing at room and elevated temperature was investigated. The densities of radiation-induced fixed traps and switching traps were determined from the sub-threshold I-V curves using the midgap technique. It was shown that the creation of fixed traps dominated during irradiation. The experimental results have also proved the existence of latent switching traps buildup process during annealing at an elevated temperature. This increase correlated with the decrease in fixed trap density. Physical and chemical processes responsible for the threshold voltage shift during irradiation have been analyzed on the basis of interactions between secondary electrons released by gamma photons with covalent bonds Sio - O and Sio - Sio. H-W model has been used for the explanation of processes leading to latent switching traps buildup at an elevated temperature and its passivation at late annealing times. [Projekat Ministarstva nauke Republike Srbije, br. 171007

  18. High gamma-rays irradiation tests of critical components for ITER (International Thermonuclear Experimental Reactor) in-vessel remote handling system

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi [Department of Fusion Engineering Research, Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Naka, Ibaraki (Japan)] [and others

    1999-02-01

    In ITER, the in-vessel remote handling is inevitably required to assemble and maintain the activated in-vessel components due to deuterium and tritium operation. Since the in-vessel remote handling system has to be operated under the intense of gamma ray irradiation, the components of the remote handling system are required to have radiation hardness so as to allow maintenance operation for a sufficient length of time under the ITER in-vessel environments. For this, the Japan, European and Russian Home Teams have extensively conducted gamma ray irradiation tests and quality improvements including optimization of material composition through ITER R and D program in order to develop radiation hard components which satisfy the doses from 10 MGy to 100 MGy at a dose rate of 1 x 10{sup 6} R/h (ITER R and D Task: T252). This report describes the latest status of radiation hard component development which has been conducted by the Japan Home Team in the ITER R and D program. The number of remote handling components tested is about seventy and these are categorized into robotics (Subtask 1), viewing system (Subtask 2) and common components (Subtask 3). The irradiation tests, including commercial base products for screening, modified products and newly developed products to improve the radiation hardness, were carried out using the gamma ray irradiation cells in Takasaki Establishment, JAERI. As a result, the development of the radiation hard components which can be tolerable for high temperature and gamma radiation has been well progressed, and many components, such as AC servo motor with ceramics insulated wire, optical periscope and CCD camera, have been newly developed. (author)

  19. High gamma-rays irradiation tests of critical components for ITER (International Thermonuclear Experimental Reactor) in-vessel remote handling system

    International Nuclear Information System (INIS)

    In ITER, the in-vessel remote handling is inevitably required to assemble and maintain the activated in-vessel components due to deuterium and tritium operation. Since the in-vessel remote handling system has to be operated under the intense of gamma ray irradiation, the components of the remote handling system are required to have radiation hardness so as to allow maintenance operation for a sufficient length of time under the ITER in-vessel environments. For this, the Japan, European and Russian Home Teams have extensively conducted gamma ray irradiation tests and quality improvements including optimization of material composition through ITER R and D program in order to develop radiation hard components which satisfy the doses from 10 MGy to 100 MGy at a dose rate of 1 x 106 R/h (ITER R and D Task: T252). This report describes the latest status of radiation hard component development which has been conducted by the Japan Home Team in the ITER R and D program. The number of remote handling components tested is about seventy and these are categorized into robotics (Subtask 1), viewing system (Subtask 2) and common components (Subtask 3). The irradiation tests, including commercial base products for screening, modified products and newly developed products to improve the radiation hardness, were carried out using the gamma ray irradiation cells in Takasaki Establishment, JAERI. As a result, the development of the radiation hard components which can be tolerable for high temperature and gamma radiation has been well progressed, and many components, such as AC servo motor with ceramics insulated wire, optical periscope and CCD camera, have been newly developed. (author)

  20. The effects of gamma-ray irradiation to strawberry (Fragaria x ananassa Duch.) calli on shoot regeneration, achene formation and morphological variations of regenerants

    International Nuclear Information System (INIS)

    Strawberry (Fragaria x ananassa 'Nyoho') calli, derived from anthers, were irradiated with gamma -ray at dosages from 100 to 1,600 Gy (10 Gy hr-1) and their effects on callus growth, plant regeneration, and somaclonal variation were analyzed. The growth of callus and percentage of plant regeneration from the callus were reduced slightly at dosages less than 200 Gy, moderately at 400 Gy, and markedly above 800 Gy. Fruit growth associated with seed fertility (>50 % ) was morphologically normal at less than 100 Gy, whereas achene formation was significantly inhibited above 200 Gy. The percentages of morphological variation in regenerants formed from the irradiated callus were:13.7 (no irradiation), 18.6 (100 Gy), 66.0 (200 Gy), 75.7 (400 Gy), and 97.0 (800 Gy). Furthermore, higher dosages yielded wider variations, e.g., thick and small leaf, light leaf color, white flesh, and long fruit. In some regenerants, more than one morphological aberrations developed, some of which were transmissible to daughter plants. These results revealed that the irradiating strawberry callus with gamma - ray resulted in a higher degree and wider spectrum of somaclonal variation than did simple callus culture. (author)

  1. Localized corrosion behavior of stainless steel in the diluted artificial sea-water contacted with zeolite under gamma-ray irradiation

    International Nuclear Information System (INIS)

    Regarding the long-term storage of spent Cs adsorption vessels containing zeolites in the Fukushima Daiichi nuclear power station, corrosion of the material of the spent Cs adsorption vessels is one of the important issues. We performed electrochemical tests of stainless steel (SUS316L) in the zeolites containing artificial seawater under gamma-ray irradiation. The spontaneous potential (ESP) and critical pitting potential (VC) of SUS316L were measured to understand the corrosion resistance of the stainless steel in this study. The rest potential of the stainless steel increased with time after gamma-ray irradiation. ESP, defined as the steady rest potential, increased with increasing dose rate; this increase in ESP was suppressed by the contact of SUS316L with the zeolites. The concentration of H2O2 in bulk water increased with increasing dose rate. This concentration increase was suppressed by the contact of SUS316L with the zeolites due to decomposition of H2O2. There was good relationship between ESP and the concentration of H2O2. The VC of SUS316L contacted with the zeolites decreased with increasing Cl- ion concentration and is slightly smaller than the VC in bulk water. The contact of SUS316L with the zeolites suppressed the increase in ESP under irradiation. The contact with the zeolites can reduce the probability of the localized corrosion of SUS316L. (author)

  2. Effect of gamma ray irradiation on the structural and electrical transport properties of PrFe{sub 1?x}Mn{sub x}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Sultan, Khalid, E-mail: ksbhat.phy@gmail.com; Ikram, M., E-mail: ksbhat.phy@gmail.com [Department of Physics, National Institute of Technology Hazratbal, Srinagar-190006, Jammu and Kashmir (India); Asokan, K. [Material Science Division, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India)

    2014-04-24

    The effect of gamma ray irradiation on the structural and transport properties of polycrystalline bulk samples of PrFe{sub 1?x}Mn{sub x}O{sub 3} (x = 0.0, 0.1, 0.5) were investigated. The samples were synthesized by solid state reaction method and exposed to {sup 60}Co gamma radiation to accumulated dose of 625 KGy. From the Raman study, the modes exhibit a blue shift with broadening of spectral features in the irradiated samples. The dielectric constant (??) was also studied as a function of frequency. The dielectric constant and ac conductivity increases with Mn doping but decrease on irradiation. Exposure to gamma radiation results in substantial modification in the physical properties of these compounds.

  3. Gamma ray astronomy

    International Nuclear Information System (INIS)

    The first certain detection of celestial high energy gamma rays came from a satellite experiment flown on the third Orbiting Solar Observatory (OSO-111). A Gamma ray spark chamber telescope with substantively greater sensitivity and angular resolution (a few degrees) flown on the second Small Astronomy Satellite (SAS-II) has now provided a better picture of the gamma ray sky, and particularly the galactic plane and pulsars. This paper will summarize the present picture of gamma ray astronomy as it has developed at this conference from measurements made with experiments carried out on balloons, those remaining on the ground, and ones flown on satellites. (orig.)

  4. Gamma-ray sources

    International Nuclear Information System (INIS)

    Results are presented from an analysis of the celestial gamma-ray fine-scale structure based on over half of the data which may ultimately be available from the COS-B satellite. A catalogue consisting of 25 gamma-ray sources measured at energies above 100 MeV is presented. (Auth.)

  5. Effect of dose-rate and age at irradiation on cancer development in Sprague-Dawley rats exposed to gamma rays

    International Nuclear Information System (INIS)

    The probability that rats develop tumors following a 3 Gy exposure to gamma rays from cobalt 60 was observed to depend on age at exposure and on dose rate. Dose rate reduction by a factor of 60 decreased the carcinogenic incidence (mainly carcinomas) by a factor of about 5. Lifetime excess of malignant neoplasia decreased by a factor of about 10 in 9 month-old rats as compared to animals irradiated in utero. The 3-month age group developed slightly fewer cancers than the group irradiated in utero, and tumor location was different. The higher incidence of tumors following in utero exposure was dependent to the high sensitivity of brain and gonads during organogenesis. (author)

  6. Biochemical and pharmacological characterization of irradiated crotamine by gamma rays of {sup 60}Co; Caracterizacao bioquimica e farmacologica da crotamina irradiada por raios gama de {sup 60}Co

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Karina Corleto

    2014-07-01

    The serum production in Brazil, the only effective treatment in cases of snakebites, uses horses that although large size, have reduced l lifespan compared with horses not immunized. Ionizing radiation has been shown as an excellent tool in reducing the toxicity of venoms and toxins isolated, and promote the achievement of better immunogens for serum production, and contributing to the welfare of serum-producing animals. It is known, however, that the effects of ionizing radiation on protein are characterized by various chemical modifications, such as fragmentation, cross-linking due to aggregation and oxidation products generated by water radiolysis. However, the action of gamma radiation on toxins is not yet fully understood structurally and pharmacologically, a fact that prevents the application of this methodology in the serum production process. So we proposed in this paper the characterization of crotamine, an important protein from the venom of Crotalus durissus terrificus species, irradiated with {sup 60}Co gamma rays. After isolating the toxin by chromatographic techniques and testing to prove the obtaining of pure crotamine, it was irradiated with gamma rays and subjected to structural analysis, Fluorescence and Circular Dichroism. Using high hydrostatic pressure tests were also conducted in order to verify that the conformational changes caused by radiation suffer modifications under high pressures. From the pharmacological point of view, muscle contraction tests were conducted with the objective of limiting the action of crotamine in smooth muscle as well as the change in the action of toxin caused structural changes to the front. Analysis of Circular Dichroism and Fluorescence showed changes in structural conformation of crotamine when subjected to gamma radiation and that such changes possibly occurring in the secondary and tertiary structure of the protein. The observed in pharmacological tests showed that the irradiated crotamine was less effective in lowering the vas deferens twitch in rats in comparison to native crotamine. In addition, the behavior of irradiated toxin in tonic contraction, modulated by noradrenaline, was different from that observed for the native toxin. (author)

  7. Comparison of base substitutions in response to nitrogen ion implantation and 60Co-gamma ray irradiation in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Xie Chuan-Xiao

    2004-01-01

    Full Text Available To identify the specificity of base substitutions, a novel experimental system was established based on rifampicin-resistant (Rif r mutant screening and sequencing of the defined region of the rpoB gene in E. coli. We focused on comparing mutational spectra of base substitutions induced by either low energy nitrogen ion beam implantation or 60Co-gamma rays. The most significant difference in the frequency of specific kinds of mutations induced by low energy nitrogen ion beam was that CG TA transitions were significantly increased from 32 to 46, AT TA transversions were doubled from 7 to 15 in 50 mutants, respectively. The preferential base substitutions induced by nitrogen ion beam implantation were CG TA transitions, AT GC transitions, AT TA transversions, which account for 92.13% (82/89 of the total. The mutations induced by 60Co-gamma rays were preferentially GC AT and AT GC transitions, which totaled 84.31% (43/51.

  8. Comparison of base substitutions in response to nitrogen ion implantation and 60Co-gamma ray irradiation in Escherichia coli

    Scientific Electronic Library Online (English)

    Xie, Chuan-Xiao; Xu, An; Wu, Li-Jun; Yao, Jian-Min; Yang, Jian-Bo; Yu, Zeng-Liang.

    Full Text Available To identify the specificity of base substitutions, a novel experimental system was established based on rifampicin-resistant (Rif r) mutant screening and sequencing of the defined region of the rpoB gene in E. coli. We focused on comparing mutational spectra of base substitutions induced by either l [...] ow energy nitrogen ion beam implantation or 60Co-gamma rays. The most significant difference in the frequency of specific kinds of mutations induced by low energy nitrogen ion beam was that CG TA transitions were significantly increased from 32 to 46, AT TA transversions were doubled from 7 to 15 in 50 mutants, respectively. The preferential base substitutions induced by nitrogen ion beam implantation were CG TA transitions, AT GC transitions, AT TA transversions, which account for 92.13% (82/89) of the total. The mutations induced by 60Co-gamma rays were preferentially GC AT and AT GC transitions, which totaled 84.31% (43/51).

  9. Time-resolved dose evaluation in an X- and gamma-ray irradiated silver-activated glass detector for three-dimensional imaging applications

    International Nuclear Information System (INIS)

    Ag-activated phosphate glass based on the radiophotoluminescence (RPL) phenomenon has been used as the most commonly known RPL material and as an accumulated-type passive detector. In this work, the transient-state evaluation of the dose distributions achieved by X- and gamma-ray irradiations within the Ag-activated phosphate glass was performed using a time-resolved technique for the first time. Specifically, the blue RPL intensity ascribed to the electron-trapped Ag0 centres as a function of the depth at the vicinity of the surface was investigated for different types of radiation and a wide range of energies. In addition, the dose distributions at each layer within the glass confirmed by the time-resolved measurement were compared with those reconstructed by a disk-type transparent glass detector based on the blue RPL with a diameter of 100 mm. - Highlights: The time-resolved dose evaluation of Ag-activated glass was performed. The RPL intensity as a function of the depth was investigated for X- and gamma-rays. The origin and mechanisms for the RPL enhancement in the near-surface layers were discussed

  10. The effects of 137Cs gamma-rays irradiation on upland cotton pollen and M1(F1M1)generation

    International Nuclear Information System (INIS)

    The radiation effects of upland cotton pollen irradiated by 137Cs gamma-rays were studied with Zhemian 9 and Zhe 102 as the research materials. The results are as follows: 1. There were significant negative correlation between radiation dosage and the vitality of upland cotton pollen with the correlation coefficient of -0.9545?-0.9785. The half-lethal dosage with pollen of Zhemian 9 and Zhe 102 was 5.50 Gy and 4.69 Gy, respectively. 2. The emergence and growth of seedlings of M1 and F1M1 generations from the pollen irradiated with dosage of more than 7.51 Gy were all significantly retarded. The induced-aberration effects varied with varieties. 3. All irradiation dosage inhibited yield and fiber qualities except 1.88 Gy. The inhibition effects of irradiation on yield components of M1 and F1M1 generations from irradiated pollen were greater than those on fiber qualities, especially on lint percentage and weight per boll. The protein content of cotton seed kernal of M1 and F1M1 generations increased with the rising of irradiation dosage, while the oil content decreased. 4. The radiosensitivity of F1M1 was higher than that of M1. It is suggested that the suitable dosage in cotton breeding should be less than 4.79 Gy

  11. Feasibility of applying gamma irradiation as disinfestation technique on date fruits in respect to nutritional value that is affected by disinfesting gamma ray doses

    International Nuclear Information System (INIS)

    Infested and non-infested dry date fruits (Phonex dactylifera), Abrimi variety (9.2% moisture), with Ephestia cautella Walker were irradiated for 0, 15, 20 and 40 Krad gamma ray doses emitted from Co-60 source with 1.36 x 10-rad/h. as a dose rate. Irradiated fruits were stored at room temperature, at 20-250C and 85-95% R.H., in packages to avoid reinfestation. A dose of 20 Krad is 100 percent effective in preventing the emergency of eggs, larva, and pupae in fruits as reflected by zero per cent emergency count for live adults. Also, this dose was found to be lethal for adult stage of the insect. On the other hand, 2 Krad dose does not produce significant changes in the nutritional qualities of fruits, as measured by chemical analytical means for carbohydrates, protein and amino acids, directly after irradiation as well as at 2, 4 and 6 months storage. The triangular tests show that irradiation treatments even with 4 Krad exerted no determinal effect upon the sensory qualities of stored irradiated date fruits. These results point out the feasibility of applying gamma irradiation, 20 Krad, as disinfestation technique against Ephestia cautella Walker in dry date fruits without exerting any effect on the nutritional value

  12. Comparison of electron beam and gamma ray irradiations effects on ruminal crude protein and amino acid degradation kinetics, and in vitro digestibility of cottonseed meal

    International Nuclear Information System (INIS)

    This study was conducted to compare effects of electron beam (EB) and gamma ray (GR) treatments at doses of 25, 50 and 75 kGy on ruminal degradation kinetics of crude protein (CP), amino acid (AA), and in vitro digestibility of cottonseed meal (CSM). Ionizing radiations of EB and GR had significant effects (P0.05). Irradiation processing caused decrement in AA degradation after 16 h of ruminal incubation (P<0.05). EB irradiation was more effective than GR irradiation in lessening the ruminal degradability of AA (P<0.05). EB and GR treatments at a dose of 75 kGy increased in vitro digestibility of CSM numerically. This study showed that EB could cause CP and AA bypass rumen as well as GR. Therefore, ionizing irradiation processing can be used as an efficient method in improving nutritional value of CSM. - Highlights: ? Irradiation was effective on reducing ruminal degradability of cottonseed meal. ? Ionizing radiations, especially electron beam, lessened ruminal degradability of amino acid substantially. ? Irradiation processing could be used as a safe and efficient method in improving nutritional value of cottonseed meal.

  13. Gamma-Ray Bursts

    OpenAIRE

    Rau, Arne

    2012-01-01

    Gamma-ray bursts are the witnesses of stellar explosions at cosmological distances and among the most energetic phenomena in the Universe. Here I present a study of the population of Gamma-ray bursts from three different observational aspects. (i) The prompt gamma-ray emission was investigated based on the event sample detected with the anti-coincidence shield of the spectrometer on-board the INTEGRAL satellite. (ii) The afterglow phase and the underlying host galaxies at optical and near-inf...

  14. Application of the radiochemical - and the direct gamma ray spectrometry method to the burnup determination of irradiated uranium oxide

    International Nuclear Information System (INIS)

    The burn up of natural U3O8 that occurs by the action of thermal neutrons was determined, using the radioisotopes 144Ce, 137Cs, 103Ru, 106Ru and 95Zr as monitors. The determination of the burn up was made using both destructive and non-destructive methods. In the non-destructive method, the technique of direct gamma-ray spectrometry was used and the radioisotopes mentioned were simultaneously counted in a Ge-Li detector. In the radiochemical method the same radioisotopes were isolated one from the other and from all other fission products before counting. The solvent extraction technique was used for the radiochemical separation of uranium, cerium, cesium and ruthenium. To separate zirconium and niobium, adsorption in silica-gel was used. The extraction agent employed to isolate cesium was dipycrilamine and for the separation of the other radioisotopes Di-(2-Ethyl Hexyl) Phosphoric acid (HDEHP) was used. (Author)

  15. Determination of absorbed dose in a patient irradiated by beams of x or gamma rays in radiotherapy procedures

    International Nuclear Information System (INIS)

    Several important changes in the underlying physical concepts of radiotherapy are discussed. Radiotherapy with external photon beams is now carried out to a very large extent with radiation of high energy. However, medium and low energy photons still have a place and give rise to problems to which special attention has to be drawn. This report will assume the use of high energy radiation (including 60Co gamma rays) unless otherwise stated. Isocentric techniques are now fairly common and the dosimetric procedures used with these techniques are somewhat different from those used with the more traditional techniques based on a fixed source-skin distance (SSD). The digital computer is widely and increasingly used as a means of calculating dose distributions and for other procedures discussed in this report

  16. Effects of gamma-ray irradiation on interface states and series-resistance characteristics of BiFeO{sub 3} MOS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, Senol, E-mail: senolkaya52@gmail.com [Physics Department, Abant Izzet Baysal University, 14280 Bolu (Turkey); Nuclear Radiation Detectors Research and Development Center, 14280 Bolu (Turkey); Aktag, Aliekber [Physics Department, Abant Izzet Baysal University, 14280 Bolu (Turkey); Nuclear Radiation Detectors Research and Development Center, 14280 Bolu (Turkey); Yilmaz, Ercan [Physics Department, Abant Izzet Baysal University, 14280 Bolu (Turkey); Nuclear Radiation Detectors Research and Development Center, 14280 Bolu (Turkey); Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

    2014-01-15

    The effects of radiation on the electrical-interface-state density (D{sub it}) and series resistance (R{sub s}) characteristics of BiFeO{sub 3} MOS capacitors were studied in this work. To study the response of MOS devices to gamma irradiation over a range of doses, MOS samples were irradiated using a Co-60 gamma-ray source from 0.5 to 16 grays at a dose rate of 0.0030 Gy/s. CV and G/?V measurements were recorded prior to and after irradiation at high (1 MHz) frequency. The effects of the radiation were determined from analysis of the CV and G/?V curves. A slightly decrease in the R{sub s} values with increasing irradiation dose was observed. The total interface-state density was found to decrease because of the reordering and restructuring of radiation-induced defects in the MOS capacitors. The experimental results indicate that the electrical R{sub s} and D{sub it} characteristics of BiFeO{sub 3} MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 10{sup 11} eV{sup ?1} cm{sup ?2}. However, the calculated D{sub it} values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range.

  17. Localization of the lactate dehydrogenase (LDH) and of the acid phosphatase (AP) in liver cells of embryos and chickens irradiated with gamma rays

    International Nuclear Information System (INIS)

    Using enzymatic histo- and cytochemical techniques, effects of acute 1000-rad gamma rays were studied with regard to changes occurring in the location and activity of the following embryonic or young chick hepatic enzymes: acid phosphatase (AP), indicative of lysosomes, and lactate dehydrogenase (LDH), involved in glycolytic metabolism. Exposures were given to 12-, 20-, or 21-day embryos and to 7-day-old chicks, and liver sections prepared 1, 24, or 72 days postradiation. Comparisons were made to unirradiated age-specific controls. Increases in AP and LDH activities were observed under all of the conditions tested, with extent of effect depending on both stage of development at exposure and time after exposure. Peak values were observed at 24 hours after irradiation of 12-day embryos. (A.B.)

  18. Morphogenetical studies on the M2- and M3-populations of wheat (Triticum aestivum ssp. vulgare L.) after seed irradiation with gamma rays

    International Nuclear Information System (INIS)

    This study deals with the irradiation induced variability in five quantitative traits of wheat. Various statistical parameters and genetic estimates were used herein to determine the magnitude of heritable and non-heritable components of variance in two successive generations (M2 and M3) after treating the seeds of a pure line of the Egyptian hexaploid wheat variety 'Giza 155' with different gamma ray doses. Results indicated a generalized reduction in the mean value of these characters observed in both generations as compared to the mother stock. However, great variability was obtained in both generations more apparent in M3 than M2. Phenotypical correlations, genotypical correlations, and heritability estimates of these characters exhibited high values. The results were represented and discussed. Conclusions were drawn and radiobiological concepts were used for better understanding of the basic feature of radiaton induced mutations. (orig.)

  19. Increase in aggressiveness of male mice after irradiation of paternal spermatozoa with 600 R of gamma-rays as dependent on fertility

    International Nuclear Information System (INIS)

    The agonistic behavior of unexperienced pairs of NMR1 male mice was determined by counting the bites received from and delivered to the opponent within 24 h. The first 10 minutes of agonistic encounters was recorded by video tape to analyze the frequency and duration of ten behavioral traits. Each pair consisted of two F1 males, one of which was derived from paternal spermatozoa irradiated with 600 R of gamma-rays, while the other stemmed from a sham-treated father. The 600-F1 males exhibited higher aggressiveness than their control F1 counterparts, in which the sterile and semisterile males showed a higher level of agonistic behavior and overall activity than the normally fertile F1 males of the same group. 600-F1 males released more urine drops than the control males. No significant differences between 600-F1 and control-F1 males or between fertile and sterile plus semisterile males were found for learning ability

  20. The role of spermatogonia in the recovery process from temporary sterility induced by gamma-ray irradiation in the teleost Oryzias latipes

    International Nuclear Information System (INIS)

    Adult males of the fish Oryzias latipes were irradiated with 0.5 or 1 kR of 137Cs-gamma-rays (100 R/min). From the viewpoint of the cell-population shift and cell differentiation, the radiation effects on the spermatogenesis in the testis were analyzed. Among the three types of spermatogonia, the first type, the spermatogonia As, were very resistant to radiation, judging from the survival of the cells, but the other types, the spermatogonia Ad and the spermatogonia B, were sensitive to radiation. The spermatogonia As began to proliferate after the degeneration and disappearance of the spermatogonia Ad following the iradiation. During the proliferation phase of the cells, some of the spermatogonia As were morphologically transformed into the spermatogonia Ad, which contributed to the repopulation of the spermatogenetic cells in the testis following the cell loss induced by radiation damage. (auth.)

  1. Time-resolved dose evaluation in an X- and gamma-ray irradiated silver-activated glass detector for three-dimensional imaging applications

    Science.gov (United States)

    Kurobori, T.; Itoi, H.; Yanagida, Y.; Chen, Y. Q.

    2015-09-01

    Ag-activated phosphate glass based on the radiophotoluminescence (RPL) phenomenon has been used as the most commonly known RPL material and as an accumulated-type passive detector. In this work, the transient-state evaluation of the dose distributions achieved by X- and gamma-ray irradiations within the Ag-activated phosphate glass was performed using a time-resolved technique for the first time. Specifically, the blue RPL intensity ascribed to the electron-trapped Ag0 centres as a function of the depth at the vicinity of the surface was investigated for different types of radiation and a wide range of energies. In addition, the dose distributions at each layer within the glass confirmed by the time-resolved measurement were compared with those reconstructed by a disk-type transparent glass detector based on the blue RPL with a diameter of 100 mm.

  2. Growth and sedimentation of fine particles produced in aqueous solutions of palladium sulfate and palladium sulfate-silver sulfate induced by gamma-ray irradiation

    International Nuclear Information System (INIS)

    It is known that palladium and palladium-silver fine particles were formed from deaerated aqueous solutions of palladium sulfate and palladium sulfate-silver sulfate induced by gamma-ray irradiation. Changes in particle size and with amount of particles in the solution with time during and after irradiation were studied using dynamic light scattering technique and UV spectrophotometer. The particles formed from palladium sulfate solution are found to be water-filled bulky particles of diameter of 200 nm, which grow by mutual coagulation even after irradiation was terminated. Average density depends on concentration of palladium ion in the solution and dose, and the lowest density was about 2 g/cm3 for particles of 200 nm obtained from 0.06 mM solution by 2.4 kGy irradiation. The average density of the particles obtained from palladium sulfate-silver sulfate solutions was smaller than those obtained for the corresponding palladium sulfate solutions. Supersonic agitation destroyed coagulated precipitates to form fine particles, but did not form clusters of a few atoms. (author)

  3. Elemental analysis of human placenta by neutron irradiation and gamma-ray spectrometry (standard, prompt and fast-neutron)

    International Nuclear Information System (INIS)

    Human placental tissue from 100 hospitalized deliveries were analysed for Ag, Al, As, Au, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, I, Hg, K, La, Mg, Mn, Mo, Na, Ni, Rb,S, Sb, Sc, Se, Sn, Sr, Ti, V, W and Zn using a combination of pre-chemical separation of sodium with hydrated antimony pentoxide and instrumental neutron activation analysis. Boron and Si values were determined using prompt gamma-ray and fast-neutron techniques respectively. Analysis of NBS-SRM Bovine Liver 1577 and a 'pooled standard' placental tissue for 33 elements showed a good agreement with most coefficients of variation less than or equal to 15%, and recoveries of 91-104%. Symmetrical distributions were obtained for all elemental placental values. Only Cd(-) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. The influence of cigarette smoking is considered a major factor in producing elevated cadmium levels in the placental tissue of smokers and passive smokers, and hence lower birth weights. (author)

  4. A study on film sensitivities influenced by the thickness of lead foils under irradiation of 192Ir gamma ray

    International Nuclear Information System (INIS)

    When the gamma ray of average energy 375KeV emitted by 192Ir is exposed to each film through lead foil with various thickness, the film sensitivity was varied with the thickness of lead foil and with film types. Different density and sensitivity ratios were appeared depending on time of exposure and the type of films. The effect of film sensitivity by the front lead foil showed rapid increase upto the thickness of more or less 0.03mm, and the thicker lead foil decreased more in the thickness of about 0.05 - 0.09 mm. The effect of film sensitivity by the back lead foil was increased upto around 0.03 - 0.08 mm thickness, the maximum sensitivity was obtained in the thickness of more than 0.03 - 0.08 mm without any change in the above effect. The sensitivity of front lead foil was higher than that of back lead foil in thin lead foil with about 0.127 mm thickness, but the sensitivity of back lead foil was higher than that of front lead foil when thickness became thicker. (author)

  5. Effects of gamma-ray and UV irradiation on the abnormal aggregation of proteins, and study of repair and protection mechanism

    International Nuclear Information System (INIS)

    Presented are following 7 Studies on the title subject. Abnormal Protein Aggregation and Amino Acid Racemization by Radiation and UV-ray, report the effects of artificial replacement of Asp76 in 70-88th residues of alphaA-crystallin (aA-cry) to L-alpha, L-beta, D-alpha and D-beta/aspartic acid on the properties of the peptide. The hydrophobicity, circular dichroism and insulin aggregation are greatly altered by the isomerization. Analysis of Radiation-induced Structural and Functional Changes around the Aspartic Acid Residues in a Protein, report an attempt to develop a method to prepare the protein with isomerized Asp residue at a specific site of aA-cry with protein ligation, which is unsuccessful. Radiation-induced Damage of Biomolecules and Its Protective Mechanism, report the effect of gamma-ray on linolenic acid and its modification by beta-carotene as carotenoids localize in the membrane lipid and participate in the radiation resistance of bacteria. The pigment is suggested to work protective against damages of biomolecules and to be under strict regulation for its intracellular level. Modeling of D-aspartic Acid Accumulation in a Protein and Its Mechanistic Regulation by the Degrading Enzyme of the Amino Acid, report the role of D-aspartyl endopeptidase, found by authors (DAEP) and dynamics of D-Asp containing protein in superoxide dismutase-deleted mice and in HepG2 cells exposed to H2O2. DAEP is suggested to be damaged by the oxidizing stress, which results in the accumulation of D-Asp containing protein possibly leading to acceleration of senescence. Dynamics and Working Mechanism of a Complicated and Huge Protein Complex, report the analysis of yeast 20S and 26S proteasome assembly using the diffusion, X-ray and small-angle neutron scattering. In Situ Observation and Analysis of Dynamics of Aggregation/Dissociation of Proteins, report that the subunit exchange between 1H- and 2H-double rings of each 7-aggregated ring of proteasome alpha7 subunit is measurable by small-angle neutron scattering alone. Comparison of Conformational Changes of Tryptophanase Induced by Ammonium Phosphate and Gamma-ray Irradiation, report that tryptophanase becomes active to D-tryptophan when exposed to the phosphate salt, but does not by 138-1106 Gy gamma ray despite a circular dichroism shift. (T.T.)

  6. Radionuclides release from re-irradiated fuel under high temperature and pressure conditions. Gamma-ray measurements of VEGA-5 test

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko; Kanazawa, Toru; Kiuchi, Toshio; Uetsuka, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program is being performed at JAERI to clarify mechanisms of radionuclides release from irradiated fuel during severe accidents and to improve source term predictability. The fifth VEGA-5 test was conducted in January 2002 to confirm the reproducibility of decrease in cesium release under elevated pressure that was observed in the VEGA-2 test and to investigate the release behavior of short-life radionuclides. The PWR fuel of 47 GWd/tU after about 8.2 years of cooling was re-irradiated at Nuclear Safety Research Reactor (NSRR) for 8 hours before the heat-up test. After that, the two pellets of 10.9 g without cladding were heated up to about 2,900 K at 1.0 MPa under the inert He condition. The experiment reconfirmed the decrease in cesium release rate under the elevated pressure. The release data on short-life radionuclides such as Ru-103, Ba-140 and Xe-133 that have never been observed in the previous VEGA tests without re-irradiation was obtained using the {gamma} ray measurement. (author)

  7. Gamma ray camera

    International Nuclear Information System (INIS)

    A gamma ray camera is disclosed for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array. 6 figs

  8. Gamma ray camera

    Science.gov (United States)

    Perez-Mendez, Victor (Berkeley, CA)

    1997-01-01

    A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

  9. Gamma ray optics

    International Nuclear Information System (INIS)

    Via refractive or diffractive scattering one can shape ? ray beams in terms of beam divergence, spot size and monochromaticity. These concepts might be particular important in combination with future highly brilliant gamma ray sources and might push the sensibility of planned experiments by several orders of magnitude. We will demonstrate the experimental feasibility of gamma ray monochromatization on a ppm level and the creation of a gamma ray beam with nanoradian divergence. The results are obtained using the inpile target position of the High Flux Reactor of the ILL Grenoble and the crystal spectrometer GAMS. Since the refractive index is believed to vanish to zero with 1/E2, the concept of refractive optics has never been considered for gamma rays. The combination of refractive optics with monochromator crystals is proposed to be a promising design. Using the crystal spectrometer GAMS, we have measured for the first time the refractive index at energies in the energy range of 180 - 2000 keV. The results indicate a deviation from simple 1/E2 extrapolation of X-ray results towards higher energies. A first interpretation of these new results will be presented. We will discuss the consequences of these results on the construction of refractive optics such as lenses or refracting prisms for gamma rays and their combination with single crystal monochromators.

  10. Gamma rays effect on cherry

    International Nuclear Information System (INIS)

    In irradiation treatment (1970-1973) of ripe cuttings of the Drogans Gelbe and Hedelfinger Riesenkirsche cherry varieties with gamma rays at the rates of 3.5 and 7 kR, 3 kR proved most effective dose. Of both varieties 16 slowly growing forms were obtained which were of interest to the clonal selection and hybridization of cherry. The results are considered as backing the formulated by Enken regularity in inducing mutations and regarding the observed morphological changes in experimental materials - a support of the report of other authors on the use of ionozing radiation applied to different fruit tree spp. (author)

  11. Comparative effect of gamma-rays and ultraviolet irradiation on sensitivities and mutation induction of escherichia coli

    International Nuclear Information System (INIS)

    Three strains of Escherichia coli, B1, B2 and B/r were irradiated with ?-rays and ultraviolet rays. E. coli B1 and B2 were isolated from E. coli B. They were inoculated on either Tryptone agar or Glucose-NH4 agar plates to observe the comparative sensitivities to the irradiations. UV irradiation was more effective for the inactivation of cells than ?-rays irradiation in all strains when compared at the same absorbed energy. The sensitivities to the irradiations were in the order of E. coli B1, B2 and B/r by both irradiations. Higher sensitivities were observed when inoculated on Glucose-NH4 agar plates than on Tryptone agar plates. Induction of mutation was also studied on lac-mutant and auxotroph. MacConkey agar plates were used to distinguish the lac-mutant from the wild type; the mutant showed whitish colonies compared to the reddish purple colonies by wild type. Auxotroph was distinguished from the wild type which formed colonies on Glucose-NH4 agar plate, while the auxotroph colonies were made after adding casamino acid onto Glucose-NH4 agar plates. Induction of lac-mutant and auxotroph by ?-irradiation was the most frequent in E. coli B/r when compared at the same survival fraction of 10-4. Induction of mutation occurred more frequently by ?-irradiation than by UV-irradiation, and more stable mutants were obtained by ?-irradiation. (J.P.N.)

  12. Gamma-ray irradiation effects on corrosion rates of stainless steel in boiling nitric acid containing ionic additives

    International Nuclear Information System (INIS)

    Irradiation effects of ?-rays on corrosion rates of type 304ULC stainless steel in 9 x 10-3 mol/m3 boiling nitric acid containing an ionic additive of multivalence elements of Ce(IV), Cr(VI) or Ru(III) were studied by measuring weight losses of specimens immersed under the 60Co ?-ray irradiation of 1 kC/(kgh) (4 MR/h). Tests without irradiation were carried out as well to obtain reference data. All the coexisting ionic species enhanced the corrosion in comparison with those in pure nitric acid, and the ?-ray irradiation moderated the enhancement. The valence analyses of these additives and redox potential measurements before and after the immersion batch under the irradiation suggested that the reduction of Ce(IV) and Cr(VI) induced by the irradiation have moderated the corrosion environment. (author)

  13. Study of uptake and endocytosis of gamma rays-irradiated crotoxin by mice peritoneal macrophages; Avaliacao do mecanismo de captacao e endocitose de crotoxina submetida a acao da radiacao, por macrofagos peritoneais de camundongos

    Energy Technology Data Exchange (ETDEWEB)

    Cardi, Bruno Andrade

    1999-07-01

    The purpose was to investigate the uptake and endocytosis of 2000 Gy {sup 60}Co irradiated crotoxin through mouse peritoneal macrophages, correlating with native one and another non related protein, the ovalbumin. Native (CTXN) or 2000 Gy {sup 60} Co {gamma}-rays (dose rate 540 Gy/hour) irradiated crotoxin (CTXI) or ovalbumin processed of same manner (OVAN - OVAI) were offered to mouse peritoneal macrophages and their uptake was evaluated by immunohistochemistry and quantitative in situ ELISA. The involvement of scavenger receptors (ScvR) was evaluated by using blockers drugs (Probuco-PBC or Dextran Sulfate - SD) or with nonspecific blocking using fetal calf serum (FBS). The morphology and viability of macrophages were preserved during the experiments. CTXI showed irradiation-induced aggregates and formation of oxidative changing were observed on this protein after gamma rays treatment. By immunohistochemistry we could observe heavy stained phagocytic vacuole on macrophages incubated with CTXI, as compared with CTXN. Quantitatively by in situ ELISA, the sema pattern was observed, displaying a 2-fold CTXI incorporation. In presence of PBC or SD we could find a significant decrease of CTXI uptake but not of CTXN. However the CTXN uptake was depressed by FBS, not observed with CTXI. OVA, after gamma rays treatment, underwent a high degradation suffering a potent incorporation and metabolism by macrophages, with a major uptake of OVAI in longer incubation (120 minutes). Gamma rays ({sup 60} Co) produced oxidative changes on CTX molecule, leading to a uptake by ScvR-mice peritoneal macrophages, suggesting that the relation antigen-presenting cells and gamma rays-modified proteins are responsible for the better immune response presented by irradiated antigens. (author)

  14. Change in erythrocyte number of rat's peripheral blood after combined irradiation with millimeter waves and gamma-rays

    International Nuclear Information System (INIS)

    Male random breed Wistar rats used in this experiment have been treated as follows: 6 Gy gamma irradiated; irradiated with 5.6 millimeter waves (MMW) and 7.1 MMW only; irradiated with 5.6 MMW and 7.1 MMW before gamma irradiation. The results show a similarity in dynamics of erythrocyte number for both frequencies used. The treatment with MMW leads to a well pronounced radioprotective effect on hemopoiesis, which is due to the stimulation of bone-marrow cells proliferation observed by other authors as well. 2 figs., 8 refs

  15. The effect of externally irradiated cobalt 60 gamma-rays on blood glutathione peroxidase activity of rabbits

    International Nuclear Information System (INIS)

    Cobalt 60 ?-rays were irradiated on male rabbits weight 2.4 to 2.6 kg at varying dose levels (50, 800, 1,500 rad on the whole body). 800 rad was irradiated on the portion of the liver, the whole body except the portion of the liver, the chest, the abdomen except the portion of the liver and on the head. The changes in blood Glutathion Peroxidase (PGO) activity were determined for one or two weeks spectrophotometrically to study the effect of irradiation. After the irradiation on the whole body, blood GPO activity showed the characteristic changes to each dose: i) after the irradiation of 50 rad (a small dose) on the whole body, the activity had a temporary rise attaining a maximum in 12 hours, and then restored to normal in 7 days: ii) with an irradiation of 800 rad (a medium dose), it showed a temporary drop immediately after the irradiation, recovery to the normal in 6 hours, and it turned to increase untill maximum was attained in 3 days, and restored to nearly normal in 14 days: iii) in the group having 1,500 rad (a large dose), GPO activity decreased immediately after the irradiation, and animals died in 1 to 3 days, without any increase of the activity: iv) after the irradiation of 800 rad on the portion of the liver, GPO activity didn't show a temporary drop compared with whole body irradiation of same dose, however same increasing pattern was shown as that of whole body irradiation: v) after the irradiation of 800 rad on the whole body except the portion of the liver, it showed a temporary drop immediately, but didn't show a increasing curve as that after the irradiation on the portion of the liver: vi) the irradiation of 800 rad on the chest and on the abdomen except the portion of the liver, showed the temporary drop immediately: vii) the irradiation of 800 rad on the head didn't change in blood GPO levels. (author)

  16. Effect of gamma-ray irradiation on the size and properties of CdS quantum dots in reverse micelles

    International Nuclear Information System (INIS)

    Cadmium sulfide quantum dots 1.35.6 nm in size have been synthesized in sodium bis(2-ethylhexy1)sulfosuccinate (AOT)waterisooctane micellar solutions with various [H2O]/[AOT] molar ratios (w=2.5, 5.0 or 10). Gamma irradiation method has been used to change the size and optical properties of quantum dots. It has been found that ?-irradiation reduces the size polydispersity of quantum dots in the micellar system and alters their fluorescent properties. Fluorescence intensity is enhanced after ?-irradiation. The average fluorescence lifetime of single quantum dots sized 5.20.4 nm increases from 5.14 to 6.39 ns after ?-irradiation at a dose of 7.9 kGy. To the best of our knowledge, this is the first report on fluorescence lifetime of single CdS quantum dots in micellar solution. - Highlights: Gamma irradiation method has been used successfully to change the size and optical properties of CdS quantum dots synthesized in micellar solutions. ?-Irradiation reduces the size polydispersity of quantum dots in the micellar system. Fluorescence intensity of CdS quantum dots is enhanced after ?-irradiation. Fluorescence lifetime of single CdS quantum dots increases after ?-irradiation

  17. Content of DNA and RNA in leucocytes of rats irradiated with nonlethal, sublethal and lethal gamma-ray doses

    International Nuclear Information System (INIS)

    The changes in the content of DNA and RNA in rat leucocytes were studied on days 1, 3 and 7 after 2, 4, 6 and 8 Gy gamma-irradiation. Measurement of DNA and RNA content showed that the decrease of nucleic acids after irradiation was caused by an abrupt fall of the content of DNA. The changes in the DNA concentration on days 1 and 3 after irradiation quantitatively depended on the radiation dose and may thus serve as indicator of the radiation damage. The rise in the DNA content in leucocytes of rats irradiated with nonlethal and sublethal doses is a good prognostic sign. The absence of increase in the DNA content in the leucocytes of rats irradiated with lethal doses signifies severe and irreversible damage

  18. Correlation between radiation-induced defects, and optical properties of pure fused silica-core optical fiber, under gamma-ray irradiation in air at 1273 K

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, B., E-mail: btsuchiya@meijo-u.ac.jp [Department of General Education, Faculty of Science and Technology, Meijo University (Japan); Kondo, S.; Tsurui, T. [Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577 (Japan); Toh, K. [Tokai Research Establishment, Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Nagata, S.; Shikama, T. [Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2011-10-01

    Radiation-induced effects on optical properties such as thermoluminescence and optical absorption of pure fused silica-core optical fibers were investigated in situ under gamma-ray irradiation at 0.16 mGy/s and 1273 K in air. The intensities of broad optical transmission peaks below 900 nm decreased due to appearances of non-bridging oxygen hole center (NBOHC), oxygen deficiency centers (ODCs), and optical leakage with increasing annealing time. The intensities of optical absorption and luminescence characteristics peaks at 1390 nm were enhanced by the increment of Si-OH concentration due to the reaction of water vapor or hydrogen with NBOHC, ODCs, and SiO{sub 2} glass network. In addition, high resolution-transmission electron microscopy (HR-TEM) showed that SiO{sub 2} crystals approximately 10 nm in diameter were formed in the clad and core of the irradiated optical fiber. The crystallization of the SiO{sub 2} glass network had greater influence on the optical transmission and luminescence properties.

  19. Correlation between radiation-induced defects, and optical properties of pure fused silica-core optical fiber, under gamma-ray irradiation in air at 1273 K

    International Nuclear Information System (INIS)

    Radiation-induced effects on optical properties such as thermoluminescence and optical absorption of pure fused silica-core optical fibers were investigated in situ under gamma-ray irradiation at 0.16 mGy/s and 1273 K in air. The intensities of broad optical transmission peaks below 900 nm decreased due to appearances of non-bridging oxygen hole center (NBOHC), oxygen deficiency centers (ODCs), and optical leakage with increasing annealing time. The intensities of optical absorption and luminescence characteristics peaks at 1390 nm were enhanced by the increment of Si-OH concentration due to the reaction of water vapor or hydrogen with NBOHC, ODCs, and SiO2 glass network. In addition, high resolution-transmission electron microscopy (HR-TEM) showed that SiO2 crystals approximately 10 nm in diameter were formed in the clad and core of the irradiated optical fiber. The crystallization of the SiO2 glass network had greater influence on the optical transmission and luminescence properties.

  20. The effect of pre-heating and pre-irradiation with gamma-rays on thermal annealing in-bis-[n-benzoil-n-(o) tolylhydroxylaminate] cooper (II)

    International Nuclear Information System (INIS)

    The main purpose of this work was to make a contribution on the study of the chemical effects of the (N,?) reaction on copper chelate. The influence of some factors such as pre-heating and pre-irradiation with gama-rays on the retention and thermal annealing of bis [N-benzoyl-N-(o)tolylhydroxylaminate] copper (II) was investigated. The complex was synthesized and later characterized by means of: determination of the melting-point, elemental analysis, infra-red and visible range absortion spectrophotometry. The compound was heated and also irradiated with gamma-rays in order to verify the effect of thermolysis on the retention. It seems that heat and gamma-radiaition can produce deffects which will lower the susceptibility of the compound to thermal annealling. On the basis on the model envolving electronic species some explanation of ours results were made and a mechanism was proposed for the retention and thermal annealing assuming the capture of free electrons and also the existence of holes. (author)

  1. Permeability Properties of Commercial Sealing Elastomers to Light Gases with and Without Irradiation

    International Nuclear Information System (INIS)

    Elastomers are commonly used as sealing materials for applications at moderate vacuum levels. Use of elastomeric seals in ITER processing systems without any other path barrier is unacceptable from tritium confinement aspects and with safety operation. Alternative sealing methods make part of intense R-and-D efforts for root fore-pumping systems in ITER. A large variety of elastomer materials are available in the market. Gas permeability performance of elastomers are known to depend on composition and other basic properties. Such differences can lead to orders of magnitude for He or H-isotopes permeabilities justifying a systematic experimental study for ranges of interest (0-1 bar, T oC). Radiation rapidly induces hardening and other property modifications, hence performance in radiation degrading environments of their sealing properties requires additional research. The screening of available commercial grades of diverse elastomeric membranes have been performed tested in the gas permeation cell rig developed in CIEMAT for out-of-irradiation qualification and compared with measurements done in a permeation cell coupling the Van de Graaff 2 MeV e- beam facility under ionizing radiation. Time lag measurement through membranes are obtained with and without irradiation. Evidenced differences in transport magnitudes are discussed in terms of composition and elastomer microstructure. Permeability values, gas pressure dependencies and transport domains are made explicit and discussed. (author)

  2. Degradation of transport critical current of Y123 and Bi(Pb)2223 HTSC ceramics under gamma-ray irradiation

    International Nuclear Information System (INIS)

    The relations of a transport critical current of high-temperature superconductors Bi(Pb)2223 and Y123 from fluence a gamma - quantum Co60 are investigated. It is established, that the reduction Jc for both materials happens in the same interval of dozes of irradiation. It can testify about unified mechanism of radiation damage in Bi(Pb)2223 and Y123 ceramics. The changes of relations of a critical current from an external magnetic field at irradiation a gamma - quantum show, that diamagnetic properties of both materials are less sensitive to irradiation, on a comparison with a critical current

  3. NewSUBARU polarized gamma-ray source

    International Nuclear Information System (INIS)

    Laser Compton scattering gamma-ray beam source was developed on BL01 of NewSUBARU synchrotron radiation facility. The gamma-ray beams were used for application experiments, a nuclear physics research, a nondestructive inspection of thick material, a magnet Compton scattering measurements, and nuclear transmutation research. Recently, new gamma-ray irradiation hutch was added to expand experimental area. Permission of radiation safety control for new hutch has been approved. In new hutch, gamma-ray photon energy of up to 76 MeV is available. Expected flux of quasi-monochromatic gamma-ray (16.7MeV, ?E/E?7.5%) is 6x105 ?/s using 10W Nd laser and 250 mA electron current. User application of this gamma-ray source will be started this fall. (author)

  4. Gamma ray calibration system

    International Nuclear Information System (INIS)

    This invention is in the field of gamma ray inspection devices for tubular products and the like employing an improved calibrating block which prevents the sensing system from being overloaded when no tubular product is present, and also provides the operator with a means for visually detecting the presence of wall thicknesses which are less than a required minimum. (author)

  5. Radiosensitizing effect of nitric oxide in tumor cells and experimental tumors irradiated with gamma rays and proton beams

    International Nuclear Information System (INIS)

    Nitric oxide (NO) has been reported to be a radiosensitizer of mammalian cells under hypoxic conditions. In a previous study, we demonstrated an enhancement in radiation response induced by NO in mouse tumor cells under aerobic conditions, with an increasing effect as a function of malignancy. The aim of the present study was to evaluate the effect of NO in tumor cells and in experimental tumors irradiated with ? rays and proton beams. Irradiations were performed with a 137Cs ? source and with proton beams generated by the TANDAR accelerator. Tumor cells were treated with the NO donor DETA-NO and the sensitizer enhancement ratio (SER) was calculated using the ? parameter of the survival curve fitted to the linear-quadratic model. Tumor cells irradiated with protons were radio sensitized by DETA-NO only in the more malignant cells irradiated with low LET protons (2.690.08 keV/?m). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with ? rays, a significantly greater effect was demonstrated in the malignant cells (MCF-7) as compared with the near normal cells (HBL-100). Moreover, a significant decrease in tumor growth was demonstrated in mice pre-treated with the NO donor spermine and irradiated with ? rays and low LET protons as compared with mice irradiated without pre-treatment with the NO donor. In conclusion, we demonstrated a differential effect of NO as a radiosensitizer of malignant cells, both with ? rays and low LET protons. This selectivity, coupled to the in vivo inhibition of tumor growth, is of great interest for the potential use of NO releasing agents in radiotherapy. (author)

  6. Effect of dose rate on inactivation of microorganisms in spices by electron-beams and gamma-rays irradiation

    Science.gov (United States)

    Ito, Hitoshi; Islam, Md. Shamsul

    1994-06-01

    Total aerobic bacteria in spices used in this study were determined to be 1 10 6 to 6 10 7 per gram. A study on the inactivation of microorganisms in spices showed that doses of 6-9kGy of EB (electron-beams) or ?-irradiation were required to reduce the total aerobic bacteria in many However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These difference of radiation sensitivities between EB and ?-rays was explained by dose rate effect on oxidation damage to microorganisms from the results of radiation sensitivities of Bacillus pumilus and B. megaterium spores at dry conditions. On the other hand, these high dose rate of EB irradiation suppressed the increase of peroxide values in spices at high dose irradiation up to 80 kGy. However, components of essential oils in spices were not changed even irradiated up to 50 kGy with EB and ?-rays.

  7. Influence of low-dose gamma-ray irradiation on mitosis and adaptive response of meristematic cells of pea rootlets

    International Nuclear Information System (INIS)

    Pea seeds (Pisum sativa) were exposed to gamma irradiation (60Co, dose 7 Gy) at different dose rates (from 0.3 cGy/h to 19.1 cGy/h). The beginning of irradiation coincided with the beginning of soaking. After the irradiation a fraction of the seeds was irradiated with 50 Gy (137Cs, dose rate 25 Gy/min) to examine the adaptive response. After 24 hours of soaking all the seeds were germinated at 25 deg C and rootlets were fixed. Mitotic index and the number of cells with chromosomal aberrations (CA) in first mitosis anaphases of the meristematic cells of rootlets were determined. After 7 cGy irradiation, judging by the above criteria, the radiation hormesis was identified at the dose rate 1.2 cGy/h. For 19.1 cGy/h damaging effect and decrease in the mitotic activity were observed. As the dose rate grows, the adaptive response is better expressed (by the analysis of CA). When the seeds are conserved at 13-14 % humidity, the CA level is higher and the adaptive response is better expressed compared to conserving at 10 % humidity. (author)

  8. Study on the properties of blend rubber prepared with grafted rubber and irradiated rubber by Gamma Rays

    International Nuclear Information System (INIS)

    The blend rubbers were prepared by mixing ?-rays irradiated and monomer grafted rubbers. The monomers, methyl methacrylate (MMA) and styrene were used separately to prepare grafted rubber by exposure to radiation. The physico-chemical properties of the blend rubbers were evaluated. The tensile strength and elongation at break of the blend rubbers decrease whereas modulus at 500% elongation, swelling ratio and permanent set increase with the increased proportion of grafted rubber in the blend. The tear strength of the blend between irradiated and styrene grafted rubbers increases with the increased proportion of grafted rubber but that of the blend of irradiated and MMA grafted rubbers remains almost constant. The blend rubber could be used for special type of application like rubber thread, tube, catheter etc

  9. Summary of preliminary studies on the effects of 60Co gamma-ray irradiation of fiber optic materials

    International Nuclear Information System (INIS)

    Absorption induced by irradiation was measured from 185 to 1500 nm, using a computer-controlled Cary 17I spectrophotometer. Results indicate that most conventional fiber core glasses develop significant absorption bands in the near uv, visible, and near infrared regions at low doses (less than 104 rad). In polystyrene, the radiation-induced absorption losses are less severe. Two types of high purity synthetic fused silica were affected least of all by irradiation. In these vitreous silicas the only significant absorption bands observed were in the ultraviolet. (21 figures)

  10. On-line bulk analysis of raw material in a cement plant using the neutron irradiation and capture gamma ray technique

    International Nuclear Information System (INIS)

    In collaboration with Ciments Lafarge, the Laboratoire central des ponts et chaussees (LCPC) has developed a technique, involving neutron irradiation, for on-line bulk analysis of raw material quality, along the input line to a cement plant, by determining the quantities of the following elements: calcium, silicon, aluminium and iron. A system was constructed and tested in a cement plant under actual service conditions. The system consists of a sampler placed on the on-stream line supplying the plant at a rate of 1000 t/h. An analysing hopper incorporating a neutron irradiation system, consisting of a 14 MeV neutron generator tube, and a gamma ray detection system, comprising a NaI(Tl) scintillator associated with a photomultiplier, are coupled to this sampler. The system is fed continuously with the raw material to be analysed. Gamma radiation spectra supplied by the detector are analysed on two distinct measurement channels. One of these channels processes the nuclear radiation generated by neutron capture phenomena, while the other channel processes the nuclear radiation resulting from neutron activation phenomena. The data collected under the operating conditions mentioned above (i.e. in real time) allows readings to be obtained every 2 min for silicon, calcium, aluminium and iron as a result of the processing method applied to gamma capture and activation spectra. A comparison was made between these measurements and the results of an analysis of the same piles, conducted simultaneously through a sampling tower delivering at an hourly rate a sample analysed in accord with the X ray fluorescence process. Comparison of the results obtained from both analysis methods highlights the advantages of the neutron irradiation process. (author). 4 figs, 2 tabs

  11. A New Mutant for Yellow Mosaic Virus Resistance in Mungbean (Vigna radiata (L.) Wilczek) Variety SML-668 by Recurrent Gamma-ray Irradiation

    International Nuclear Information System (INIS)

    The mungbean variety SML-668 is early, high-yielding and large-seeded but susceptible to yellow mosaic virus (YMV) disease. To develop YMV resistance in SML-668, a mutation breeding programme has been undertaken. Seeds of SML-668 were irradiated with 600Gy Gamma-rays and planted in the field. Three thousand plants in M1 generation were harvested separately and planted in M2. Ninety lines showed sterility and only 10 lines showed mutants for chlorophyll, small seed size, short pod length, dwarf plant type and profuse branching, but there was no YMV-resistant mutant. All the mutants along with normal plants of the segregating lines were harvested separately in M2. In M3 generation 2,500 normal lines were planted as single plant progenies and screened for YMV resistance and did not observe any YMV resistant mutant. Hence, the normal M3 lines were made into two separate bulks and one bulk was irradiated with 500Gy as a recurrent irradiation and another was sown as it is. In M3M1 generation, a mutant showing very minor leaf symptoms for YMV, and without any pod symptoms was isolated. Th mutant was purified by growing up to M3M6 generations. All the mutant plants showed very minor leaf symptoms but no symptoms in the pod. The pods and seeds were normal and also gave normal yield as compare to highly resistant check where two recessive genes controlling resistance is reported. The susceptible plants showed leaf and pod symptoms an showed severe yield losses. This mutant was used in crossing programme to study the genetics of YMV resistance. (author)

  12. Gamma rays from Galactic pulsars

    OpenAIRE

    Calore, Francesca; Di Mauro, Mattia; Donato, Fiorenza

    2014-01-01

    Gamma rays from young pulsars and milli-second pulsars are expected to contribute to the diffuse gamma-ray emission measured by the {\\it Fermi} Large Area Telescope (LAT) at high latitudes. We derive the contribution of the pulsars undetected counterpart by using information from radio to gamma rays and we show that they explain only a small fraction of the isotropic diffuse gamma-ray background.

  13. Influence of Melatonin on The Ultrastructure of Posterior Midgut of Male Ceratitis Capitata (Wied.) Irradiated With Gamma Rays

    International Nuclear Information System (INIS)

    The basic architecture and organization of the posterior midgut epithelial cells in male med flies, Ceratitis capitata (Diptera, Tephtitidae), have been inspected after being subjected to sterilizing dose of gamma radiation (90 Gy). Their midgut cells damages were monitored by means of electron microscope. The treated cells were swollen and have slight vacuolation and increase of vesicles. The ground cytoplasm contained large vacuoles of myelinoid bodies, slight irregularity of few RER, lipid droplets and multi vesicular bodies. Some mitochondria were polymorlyphic owing to swelling of membrane or fusion together to form various shapes. Midgut epithelial cells of insects pre-treated with melatonin prior to gamma irradiation showed approximately normal structures, and preservation could be observed. The combined treatment by irradiation and melatonin could be successfully used to reduce the adverse effects of irradiation and subsequently can be used in the integrated pest management to help in the success of the sterile insect technique against the insects as well as to minimize complications of irradiation on sensitive non-target organs. This has many applications during radiotherapy for patients with cancer

  14. Changes of hypoxia inducible factor-1 α in hepatoma cells irradiated by gamma ray and their mechanism

    International Nuclear Information System (INIS)

    This paper reports regulation of hypoxia inducible factor-1 α (HIF-1 α)in hepatoma cells by irradiation. Cobalt chloride (CoCl2), a chemical mimic agent for hypoxia research, was utilized to induce the stable expression of HIF-1 α in HepG2 cells. The HepG2 cells were irradiated to different doses to observe the changes of HIF-1 α. The level of intracellular reactive oxygen species (ROS) was assayed by fluorescent microscope and flow cytometry (FCM). The results showed that there were obvious changes in expression of HIF-1 α after HepG2 cells exposed to radiation, and the changes were positively related with the irradiation dose from 1 Gy to 5 Gy. Moreover, contents of incellular ROS were negatively correlated with above levels of HIF-1 α from 1 Gy to 3 Gy. The results indicate that irradiation may enhance hypoxic cells HIF-1 α, and the reduction of intracellular ROS can contribute to the regulation of ionizing radiation on HIF-1 α. (authors)

  15. Standard test method for determining the content of cesium-137 in irradiated nuclear fuels by high-resolution gamma-ray spectral analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the determination of the number of atoms of 137Cs in aqueous solutions of irradiated uranium and plutonium nuclear fuel. When combined with a method for determining the initial number of fissile atoms in the fuel, the results of this analysis allows atom percent fission (burn-up) to be calculated (1). The determination of atom percent fission, uranium and plutonium concentrations, and isotopic abundances are covered in Test Methods E 267 and E 321. 1.2 137Cs is not suitable as a fission monitor for samples that may have lost cesium during reactor operation. For example, a large temperature gradient enhances 137Cs migration from the fuel region to cooler regions such as the radial fuel-clad gap, or, to a lesser extent, towards the axial fuel end. 1.3 A nonuniform 137Cs distribution should alert the analyst to the potential loss of the fission product nuclide. The 137Cs distribution may be ascertained by an axial gamma-ray scan of the fuel element to be assayed. In a mixed-oxide fu...

  16. Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

    Energy Technology Data Exchange (ETDEWEB)

    Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-07-01

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of {sup 235}U by monitoring its delayed high energy ?-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of {sup 235}U in the oxide samples with this set-up is estimated to be 14 mg.

  17. Cloning and molecular analysis of GA2ox1 gene mutation generated by gamma-ray 60Co irradiation in mutagenized Tamxoan - TDB06 rice cultivar

    International Nuclear Information System (INIS)

    In the present study, we have used various rice cultivars such as Nipponbare, Tamxoan Hai Hau and mutagenized TDB06 which was obtained from Tamxoan Hai Hau calli irradiated by gamma-ray 60Co with the aim of cloning, sequencing and investigating the molecular mutants of GA2ox1 gene which regulates the height of rice cultivars. Interestingly, we have found that the nucleotide sequence of GA2ox1 gene of mutagenized TDB06 is slightly changed compare to that of original Tamxoan Hai Hau and Nipponbare. The GA2ox1 gene sequence differences of mutagenized TDB06 compared to Tamxoan Hai Hau and Nipponbare are 9 and 2 nucleotides, respectively. We have also shown that the amino acid sequence of GA2ox1 protein is also different among various cultivars in which amino acids corresponding to positions 137 (Alanine), 167 (Threonine), 222 (Valine), 227 (Histidin) of mutagenized TDB06 were replaced with other amino acids Valine, Alanine, Arginine and Lysin, respectively. Nucleotide sequences of GA2ox1 gene isolated from mutagenized TDB06 and Tamxoan Hai Hau cultivars have been registered in Genbank/NCBI with accession numbers EF164903 and EF164904. Based on these initial results, we continuously isolate genes related to dwarf character, construct vectors and do transformation. This strategy can significantly contribute to improve efficiency of rice breeding in Vietnam. (author)

  18. A three-dimensional imaging detector based on nano-scale silver-related defects in X- and gamma-ray-irradiated glasses

    Science.gov (United States)

    Kurobori, Toshio; Yanagida, Yuka; Chen, Yao Qiang

    2016-02-01

    Ag-activated phosphate glass, which is the most commonly known radiophotoluminescent (RPL) material, has the capability to operate not only dosimeters but also two- and three-dimensional (2D and 3D) dose imaging detectors in the same host. This passive detector is based on radiation-induced, optically active nano-scale defects. In this work, the transient-state optical properties of the blue and orange RPL were investigated using a time-resolved spectrum technique for 137Cs and 60Co gamma-ray-irradiated Ag-activated phosphate glass. Specifically, the blue RPL intensity with a decay time of 5 ns as a function of the depth at the vicinity of the surface was systematically examined to clarify an accurate dose distribution within the glass. Moreover, a feasibility study into the use of an RPL Ag-activated phosphate glass detector for fluorescent nuclear track imaging was demonstrated using a confocal fluorescence image microscope for the first time.

  19. Effects of gamma-ray irradiation on interspecific hybridization between Chamaecyparis obtusa S. et Z. and Chamaecyparis pisifera S. et Z

    International Nuclear Information System (INIS)

    C. obtusa S. et Z. is one of the most important forest trees in Japan, and possesses high wood quality. It adapts to dry or semi-dry planting sites, but when it is planted in humid and productive soil, physiological damage is often seen, and its woods are not resistant against termite harm. On the contrary, C. pisifera S. et Z. has high adaptability to humid and productive soil, and is resistant against termite harm. In order to improve the resistance of C. obtusa against diseases and insects, an attempt to obtain a hybrid between C. obtusa and C. pisifera has been made. However, it was found to be very difficult to obtain the hybrid because of low cross compatibility. Therefore, the radiosensitivity of reproductive organs and the induction of mutation in C. obtusa and C. pisifera, the cause of interspecific incompatibility between both species, and the possibility of breaking down the incompatibility were investigated. Also, the cytological screening of the hybrids between C. obtusa and C. pisifera was made. It was considered that the acute gamma-ray irradiation from 500 to 600 R on male flowers was optimum for the hybridization of the present purpose. All of the hybrids produced in this study were triploid. (Kako, I.)

  20. Influence of irradiation with {gamma}-ray photons on the photoluminescence of Cd{sub 0.9}Zn{sub 0.1}Te crystals preliminarily subjected to the intense radiation of a neodymium laser

    Energy Technology Data Exchange (ETDEWEB)

    Glinchuk, K. D. [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine); Medvid' , A. P.; Mychko, A. M. [Riga Technical University (Latvia); Naseka, Yu. M.; Prokhorovich, A. V.; Strilchuk, O. M., E-mail: strilchuk@isp.kiev.ua [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine)

    2013-04-15

    The effect of the preliminary treatment of Cd{sub 0.9}Zn{sub 0.1}Te crystals with high-power pulses of neodymium laser radiation (the power density is {<=}1.8 MW/cm{sup 2}, at a wavelength of 532 nm) on the low-temperature (5 K) photoluminescence induced by {gamma}-ray radiation (the dose was {Phi}{sub {gamma}} = 5 kGy) is studied. The luminescence bands are related to radiation-stimulated donor-acceptor pairs, which include shallow neutral donors and neutral cadmium vacancies stimulated by {gamma}-ray irradiation, the transition of free electrons to neutral cadmium vacancies formed by radiation, and the annihilation of excitons bound to the above vacancies. It is shown that, in the crystals preliminarily treated with laser radiation, the intensity of the {gamma}-ray-stimulated luminescence bands is significantly lower than in crystals not subjected to laser radiation. This fact is accounted for by a decrease in the concentration of cadmium vacancies generated by the {gamma}-ray radiation as a result of their annihilation during the course of their interaction with laser-stimulated defects, in particular, as a consequence of their recombination at laser-stimulated interstitial cadmium atoms.

  1. Thermoluminescence, thermoluminescence emission and optical absorption of CsI:Pb2+ crystals irradiated with gamma rays

    International Nuclear Information System (INIS)

    Thermoluminescence, thermoluminescence emission and optical absorption studies have been made in lead doped cesium iodide crystal. Unirradiated crystal gives rise to optical absorption bands at 275, 230, 225 and 213 nm which are identified as the A,B,C,D, bands respectively of the lead impurity. The bands formed on irradiation at 382 nm and 331 nm are attributed to the Pb+ and Pb centres formed on irradiation. The TL glow curves show a peak at 383 K and a shoulder at 423 K. The peak at 383 K has emission at 330, 450 and 550* nm while the shoulder at 423 K has emission at 550 nm only. These peaks are attributed to Pb+ and Pb 0. (author). 15 refs., 5 figs

  2. Thermoluminescence characteristics of Nd-doped SiO2 optical fibers irradiated with the 60Co gamma rays

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) properties (radiation sensitivity, dose response, signal fading) of Nd-doped SiO2 optical fibers irradiated with 1.25 MeV photons to 150 Gy were studied. The peak of the glow curve is around 190 C regardless of the dose. The dose response is linear up to 50 Gy. The radiation sensitivity is 219 nC mg?1 Gy?1. The fiber can be a potential candidate for photon radiotherapy dosimetry due to its high radiation sensitivity, linear dose response in a wide range, slow fading, and high spatial resolution due to the small size of the fiber. - Highlights: First study of Nd+3 doped optical fibers irradiated by 1250 keV gamma radiation. Linear response of optical fiber doped with neodymium. The peak intensity of TL response for 60 Gy is twice that of the 30 Gy. A potential candidate for photon radiotherapy dosimetry

  3. Effect of spermidine on the survival of saccharomyces cerevisiae cells irradiated with different doses of gamma rays

    International Nuclear Information System (INIS)

    Saccharomyces cerevisiae cells were used to test the radioprotective effect of added spermidine [H3N(CH2)3NH2(CH2)4NH3]3+ as one of the natural polyamines that are essential for cell life. Spermidine plays an important role in suppressing radiation damages at certain concentration (10-5M/L), either via scavenging free radicals or via reducing the frequency of radiation - induced mutations. Spermidine increased noticeably the D10 value at concentration of 10-5 M/L compared with the other two used concentrations of 10-6 and 10-4 M/L. Applying spermidine before irradiation was more effective than applying it after irradiation. (author)

  4. Resveratrol effects on life span and fertility of caenorhabditis elegans subject to 60Co gamma ray irradiation

    International Nuclear Information System (INIS)

    Caennorhabditis elegans was used as experimental model to investigate radiation effect of resveratrol on caenorhabditis elegans irradiated by 60Co ? ray. Treatment with resveratrol can increase average life span and spawning rate, improve the survival rate of eggs, and protect their mitochondrion function of caenorhabditis elegans exposure to 60Co ? ray. The results indicate that resveratrol has radiation protection effects, which might be related to its action on ROS decrease and mitochondrial defend. (authors)

  5. Identification of gamma ray irradiated and unirradiated foodstuffs by electron spin resonance (ESR) and thermoluminescence (TL) techniques

    International Nuclear Information System (INIS)

    In this study, the identification of irradiated food samples containing cellulose, bone and sugar was done by Electron Spin Resonance (ESR) technique. The change of ESR signal intensities using in this identification process with radiation dose and storage time was followed. The radiation induced ESR signal intensities of sugar, green tea, sage tea, lentil and shrimp samples increased with increasing dose. It was not observed any significant change on the ESR signal intensities of sugar samples with storage time at ambient temperature. But the radiation induced ESR signal intensities for the other samples decreased with time at ambient temperature. In this work, for red lentil samples, the changes of ESR spectral parameters of heat-induced free radical ESR signals with heating temperatures were also investigated. It has investigated also that whether a possible radiation treatment could be identified of red pepper samples sold in Turkish markets using Thermoluminescence method which have been adopted or proposed TS EN 1788:2007 Standard (Foodstuffs-Detection of Irradiated Food From Which Silicate Minerals Can be Isolated-Method by Thermoluminescence). Firstly, the glow curve of silicate minerals isolated from the red pepper samples has been recorded (TL1), and after a subsequent exposure of the already measured minerals to a defined radiation gamma dose (1kGy) has been recorded as a second glow curve (TL2). It has been concluded that the red pepper samples have not been irradiated evaluating the glow curve shapes and the TL glow ratios (TL1/TL2).

  6. Some aspects of the behavior at different ages of Ceratitis capitata (Wiedemann, 1824) (Diptera-Tephritidae) irradiated with gamma rays

    International Nuclear Information System (INIS)

    The present work was carried out in the laboratory of the Entomology Section of the Nuclear Energy for Agriculture Center (CENA) in Piracicaba, Sao Paulo state, Brazil, to determine the effects different gamma radiation doses on the reproductive potential of males and the flight behavior of Ceratitis capitata (Wied.). For all the treatments with gamma radiation a Cobalt-60 source type Gamma beam-650 was used, with activity of approximately 13,410 x 10B Bq. (4,967 Ci.), and the dose rate of 2.000 Gy per hour. The doses used were 80 Gy, 100 Gy and 120 Gy. The three doses employed affected more the longevity of males than the females and the number of spermatozoid found lower in the irradiated insects compared with the control, with no significant differences between doses. The insects irradiated with 80 Gy showed activity similar to the control population until four days after emergence: afterwards they were more active than the unirradiated. The gamma irradiation diminished the take-off ability of the insects. (author). 59 refs., 9 figs., 9 tabs

  7. Effect of condition of the water in cement paste for hydrogen gas generated by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Some low level radioactive wastes are required to be solidified with cementitious material in the package. The hydrogen gas is generated from cementitious material by the radiolysis. The irradiation experiment was made to estimate the amount of hydrogen gas generation from cement paste by classified water in cement paste into two kinds that were the free water and the chemically combined water. The G values of the hydrogen gas ranged from 0.06 to 0.12 in powdered sample and from 0.08 to 0.15 in solid sample. The free water in the cement paste was found to be the main source to generate hydrogen gas by the irradiation, and the chemically combined water in cement paste can be ignored in the hydrogen gas generation. The G value of free water in the cement paste was 0.35±0.15. As the hydrogen gas generated from cement paste is calculated, it is computable by the use of G value of free water in cement paste for the amount of free water. The amount of the hydrogen gas generation is smaller than the hydrogen gas calculated by using the G value of 0.45 and by the assumption that all water in the cement sample was decomposed by irradiation. (author)

  8. Approach to the resistance of exportation tebo worms when irradiated with gamma ray through a quarantine treatment

    International Nuclear Information System (INIS)

    The tebo worms or butterworms (Chilecomadia moorei) are widely used in Chile in fishing, and so are in the international markets although there are some countries, that use these species, to a less extent for preparing food reptiles. Some foreign countries requirements demand, from the exporters, to carry out quarantine treatments related to the sterilization by ionizing energy, however customers need to make sure about their products safety and that is why it is compulsory to establish limits in connection with worms' irradiation resistance. The irradiation effect on a worms sample using doses of 0.3; 0.45; 0.6 and 0.9 kGy was studied macroscopically, after 1 hour, and then 30, 60 and 90 days after the treatment. One of the equipment utilized had a Cobalt 60 source, where as the other one had Cesium 137 irradiators, with a dose rate of 42.7 Gy minute (min)-1 and 37.1 Gy min-1, respectively. The results concluded that tebo worms can resist more than 3 times the doses suggested by the meta countries without reducing the population drastically, nevertheless it is required to increase the number of worms to be analyzed in order to validate the findings. (author)

  9. Studies into the variability in the tryptophan content induced by irradiation with gamma rays for different wheat varieties

    International Nuclear Information System (INIS)

    Air dry seeds of three wheat varieties - Sadovo 1, Ludogorka and Altimir 67 were 10 and 15 krad irradiated. The crude protein and tryptophan content was determined in M2 plants and compared with non-irradiated control plants. It was established that the three varieties under study show different reaction to gamma radiation. The crude protein and tryptiphan content in the M2 plants of the Sadovo 1 and Altimir 67 varieties after 10 krad irradiation was negative compared to the average one. After 15 krad radiation the average crude protein and tryptiphan content in the Altimir 67 M2 plants was negligably different from the control ones. The M2 Altimir 67 plants average crude protein and tryptophan content after 15 krad radiation is higher than the control one e.g. it is not negative. With a view of selection the M2 plants of Sadovo 1 and Altimir 67 varieties prove more suitable taking into consideration the crude protein and tryptophan content changes. (authors)

  10. Changes in the microflora of Vienna sausages after irradiation with gamma-rays and storage at 10 deg C

    International Nuclear Information System (INIS)

    The species of microorganisms which can grow on commercial viennas on the storage at 10 deg C were Lactobacillus, Streptococcus and yeasts. When the viennas specially made which did not contain preservatives in it were used for this investigation, growth of microorganisms such as Lactobacillus, Streptococcus, Micrococcus, Bacillus and yeasts were predominant on the storage at 10 deg C, and Pseudomonas and molds some time propagated. When smoked-viennas specially made for the National Project were used for preservation, growth of microorganisms consisted mainly of the species of Lactobacillus, Micrococcus, Acinetobacter, Flavobacterium, Streptococcus, Serratia, Corynebacterium and yeasts. Irradiation of viennas at 300 and 500 krad reduced the aforementioned flora to the Lactobacillus, Streptococcus, Acinetobacter and yeasts. The number of microorganisms on the viennas packed with nitrogen gas was not increased for 3 to 7 days by means of 300 krad irradiation, and extended the storage-life 2 to 3 times. When irradiated with a dose of 500 krad, the number of microorganisms was not increased for 9 to 14 days on the storage at 10 deg C. (author)

  11. Gamma ray camera

    International Nuclear Information System (INIS)

    An Anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the Anger camera. The image intensifier tube has a negatively charged flat scintillator screen, a flat photocathode layer, and a grounded, flat output phosphor display screen, all of which have the same dimension to maintain unit image magnification; all components are contained within a grounded metallic tube, with a metallic, inwardly curved input window between the scintillator screen and a collimator. The display screen can be viewed by an array of photomultipliers or solid state detectors. There are two photocathodes and two phosphor screens to give a two stage intensification, the two stages being optically coupled by a light guide. (author)

  12. Gamma ray beam transmutation

    International Nuclear Information System (INIS)

    We have proposed a new approach to nuclear transmutation by a gamma ray beam of Compton scattered laser photon. We obtained 20 MeV gamma ray in this way to obtain transmutation rates with the giant resonance of 197Au and 129Iodine. The rate of the transmutation agreed with the theoretical calculation. Experiments on energy spectrum of positron, electron and neutron from targets were performed for the energy balance and design of the system scheme. The reaction rate was about 1.5?4% for appropriate photon energies and neutron production rate was up to 4% in the measurements. We had stored laser photon more than 5000 times in a small cavity which implied for a significant improvement of system efficiency. Using these technologies, we have designed an actual transmutation system for 129Iodine which has a 16 million year's activity. In my presentation, I will address the properties of this scheme, experiments results and transmutation system for iodine transmutation

  13. Thermoluminescence characteristics of Nd-doped SiO2 optical fibers irradiated with the (60)Co gamma rays.

    Science.gov (United States)

    Refaei, Azadeh; Wagiran, Husin; Saeed, M A; Hosssain, I

    2014-12-01

    Thermoluminescence (TL) properties (radiation sensitivity, dose response, signal fading) of Nd-doped SiO2 optical fibers irradiated with 1.25MeV photons to 1-50Gy were studied. The peak of the glow curve is around 190C regardless of the dose. The dose response is linear up to 50Gy. The radiation sensitivity is 219nCmg(-1)Gy(-1). The fiber can be a potential candidate for photon radiotherapy dosimetry due to its high radiation sensitivity, linear dose response in a wide range, slow fading, and high spatial resolution due to the small size of the fiber. PMID:25146569

  14. Study of the ionization of alkane-electron scavenger reactant mixtures irradiated by 60Co gamma rays

    International Nuclear Information System (INIS)

    This study deals with ionization of alkane-electron scavenger reactant mixtures, irradiated by 60Co γ-rays. It is shown that the extrapolated free-ion yields (extrapolated yield method) decrease with the reactant concentration. On the basis of ONSAGER model and theoretical treatment of MOZUMDER, the cross sections of epithermal electron attachment in hexane, cyclohexane, 2,2-dimethylbutane, cyclopentane, 2,2,4-trimethylpentane for CCl4, C7F14, C6H5Br, C6H5Cl, C6F14, (C6H5)2 are determined. A comparison between gas-phase and liquid-phase cross sections is established

  15. Mechanical properties and failure surfaces of gamma-ray irradiated systems based on thermoplastic 1,2 polybutadiene

    Science.gov (United States)

    Bhagawan, S. S.; Kuriakose, B.; De, S. K.

    The effect of 60Co gamma-radiation on the mechanical properties of clay filled and unfilled 1,2 polybutadiene (1,2 PBD) and 1,2 PBD-natural rubber (NR) blends has been investigated. In the case of blends the effects on blend ratio and filler have been studied with reference to absorbed radiation dose varying from 0.1 to 100 Mrad at room temperature. Radiation was found to transform the flexible samples to brittle and rigid materials especially at high dose levels. The stress-strain behaviour, tensile strength, elongation, tension set and crosslink density were found to be markedly affected at dose levels of 10 Mrad and above. On irradiation 1,2 PBD was found to undergo predominantly crosslinking while the blends exhibited both crosslinking and chain scission due to the presence of NR. The tensile fracture surfaces of the irradiated samples were examined by scanning electron microscope (SEM) in order to gain insight into the mechanism of failure.

  16. Gamma-ray irradiation hardness of arrayed silicon microhole-based radial pn junction solar cells

    International Nuclear Information System (INIS)

    The ?-ray irradiation hardness of arrayed silicon microhole-based radial pn junction (ASMRJ) solar cells (SCs) has been experimentally studied. It was found that the sidewall morphology of the microhole arrays had an important effect on the radiation hardness, so the 4m-pitch ASMRJ SCs with hole arrays' sidewalls both unpassivated and passivated were made and referred to as 4m-U-ASMRJ and -P-ASMRJ SCs, respectively. On increasing the radiation doses, in contrast with the monotonous and rapid degradation of short circuit current density and open circuit voltage for the planar SCs, these parameters for the 4m-U-ASMRJ SCs show a small increase in the initial stage of ?-ray irradiation and then a slow decline. Average conversion efficiency shows an initial slight ascent by 4.5%. Additionally, the average conversion efficiency for the 2m-U-ASMRJ SCs shows an initial slight ascent by 5.7%. When the radiation doses grow to 8נ106rad, the average conversion efficiency degradation rates for the 2m- and 4m-U-ASMRJ SCs are 14% and 15%, respectively, whereas it is 39% for the planar SCs. The radiation-gettering mechanism is suggested to explain the radiation-hardened properties of the U-ASMRJ SCs. (paper)

  17. Chemical changes in the chloroform-paraffin-dye system irradiated with 60Co gamma-rays, 2

    International Nuclear Information System (INIS)

    Studies have been carried out on the amount of hydrogen chloride formed by the radiolysis of chloroform in a solid paraffin-chloroform-Methyl Yellow system, and the color changes from yellow to red and absorption energy observed. The amount of hydrogen chloride formed and the intensity of the red color were determined with a pH meter, a spectrophotometer, and a color/ color-difference meter. It was found that the color-difference meter had the most excellent spectral response and sensitivity for measurement of the irradiated sample, and that the color-difference, ?E, obtained by reflectometry increased proportionally with the increase in the radiation dose throughout a region of 100 -- 5000 R. When a solid sample composed of 1.0 kg paraffin (m.p. 62 -- 640C), 0.74 kg chloroform and 3.4 x 10-3 mol Methyl Yellow was subjected to 1000 R irradiation at 200C, 2.5 x 1014 molecules of hydrogen chloride were formed in 1.0 g of the solid sample with the absorption energy of 5.9 x 1016 eV, 3.2 x 1016 eV of which contributed to chloroform as the absorption energy. (author)

  18. The Effect Of SEA On Long Tail Monkeys (Macaca Fascicularis) Lymphocyte Culture Gamma Ray-Irradiated In Vitro

    International Nuclear Information System (INIS)

    Staphylococus enteroxine (SEA) is one of toxins produced by the bacterium Staphylococus aureus. In the culture, SEA has proven as a potent stimulator of lymphocytes in man event at fg/ml concentrations. This research studied the effect of SEA compared to Phytohaemagglutinine (PHA) on the peripheral blood lymphocytes culture of the long-tail monkeys. About 5 ml blood was collected from 5 monkeys and irradiated using Gamma Cell-220 P3TIR with doses of 0 (control); 1.0; 2.0; 3.0 and 4.0 Gy. The blood samples were cultured in the appropriate growth medium based on standard procedure and added with 1.0 ml (0.5 mug/ml) SEA or 0.15 ml PHA. The cultures were then incubated for 96 hours and prepared the slides. The results showed that on the unirradiated peripheral blood lymphocytes of long-tail monkeys the mitotic indices obtained using PHA and SEA are relatively similar. On the irradiated lymphocytes with doses of 1-3 Gy, the mitotic indices using SEA are relatively higher than that of PHA. Dose responses of dicentric, ring and acentric fragment of both PHA and SEA are relatively the same

  19. Effect of pelvic irradiation of lactose absorption. [. gamma. rays or x rays were used in gynecologic malignancy therapy

    Energy Technology Data Exchange (ETDEWEB)

    Stryker, J.A.; Mortel, R.; Hepner, G.W.

    1978-01-01

    Twenty-four patients undergoing pelvic irradiation for gynecologic malignancies had /sup 14/C-lactose breath tests performed in the first and fifth weeks of their treatment. The /sup 14/C-lactose breath test was performed by administering 2 ..mu..Ci of /sup 14/C-lactose by mouth along with 50 g of lactose. Breath samples were collected in ethanolic hyamine 1, 2, and 3 hr later; the radioactivity of the trapped /sup 14/CO/sub 2/ was determined by liquid scintillation spectroscopy. In the first week of treatment the percentage of administered /sup 14/C excreted as /sup 14/CO/sub 2/ at 1, 2, and 3 hr was 1.7 +- 0.8% (mean +- SD), 4.5 +- 1.6%, and 5.8 +- 1.4%, respectively. In the fifth week of treatment the 1-hr, 2-hr, and 3-hr values were 1.2 +- 0.9%, 3.6 +- 2.0%, and 4.7 +- 1.9%, respectively. The difference between the first week and fifth week test results at 1, 2, and 3 hr was statistically significant (t = 2.64, p < 0.02), (t = 2.24, p < 0.05), (t = 2.95, p < 0.01). There was a negative correlation between the 1-hr /sup 14/C-lactose breath test results in the fifth week and the stool frequency at that time (r = -0.44, p < 0.05). Seven of 12 patients whose 1 hr /sup 14/C-lactose breath test results in the fifth week were below normal (<1.2%) had nausea at that time. The data suggest that in some patients, lactose malabsorption as a result of the effect of radiation on small intestinal function may be etiologically related to the symptoms of nausea and diarrhea which occur commonly in patients who are undergoing pelvic irradiation. In addition, the results suggest that lactose-containing foods should be restricted in some patients who are undergoing pelvic irradiation to prevent symptoms resulting from radiation-induced lactose intolerance.

  20. Formation of radical cations and dose response of alpha-terthiophene-cellulose triacetate films irradiated by electrons and gamma rays

    CERN Document Server

    Emmi, S S; Ceroni, P; D'Angelantonio, M; Lavalle, M; Fuochi, P G; Kovcs, A

    2002-01-01

    The radiation-induced UV-vis spectrum of alpha-terthiophene radical cation in solid is reported. The radical cation initiates an oligomerization in the CTA matrix producing permanently coloured conjugated polarons. The specific net absorbance at 465 nm is linearly related with dose up to 2x10 sup sup 6 sup sup G y, for electrons and gamma irradiation. The decrease of the UV typical absorption (355 nm) and of four IR bands of alpha-terthiophene is linear with dose, as well. Although sensitivity is influenced by dose rate, it turned out that a linear relationship holds between sensitivity and log dose rate, in the range from 2 to 10 sup sup 5 Gy, min. These findings suggest a potential application of the system for dosimetric purposes over a wide range of dose and dose rate.

  1. Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Soo; Lim, Youn Mook; Gwon, Hui Jeong; Choi, Bo Ram; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-12-15

    Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells.

  2. Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

    International Nuclear Information System (INIS)

    Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells

  3. Dependence of free ion yield on electrical field strength in some liquid alkanes irradiated by 60 Co gamma rays

    International Nuclear Information System (INIS)

    The dependence of the free ion yield, Gsub(fi), on electrical field strength was determined in four liquid alkanes: n-hexane, 2,2-dimethyl butane, 2,2,4-trimethylpentane and 2,2-dimethylpropane irradiated by 60Co ? rays at several temperatures. The sample purity effect on Gsub(fi) values has also been investigated. The Onsager theory applied to the experimental Gsub(fi) = f(E) curves allowed to estimate the distribution function F(r) of the initial separation distances r of ions in these alkanes. A modified exponential distribution seems to be the most suitable. The Jaffe theory to 2,2-dimethylpropane results permitted to determine the total ion yield value, Gsub(tot), for this liquid: Gsub(tot) = 4.3 +- 0.3

  4. Detecting onset of chain scission and crosslinking of ?-ray irradiated elastomer surfaces using frictional force microscopy

    Science.gov (United States)

    Banerjee, S.; Sinha, N. K.; Gayathri, N.; Ponraju, D.; Dash, S.; Tyagi, A. K.; Raj, Baldev

    2007-02-01

    We report here that atomic force microscopy (AFM) in frictional force mode can be used to detect the onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers, (1) ethylene-propylene-diene monomer rubber and (2) fluorocarbon rubber, upon ?-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the ?-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behaviour of increase in its frictional property has been attributed to the onset of chain scission, and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes observed in the overall frictional property as a function of the ?-ray dose rate for the two elastomers are presented in this paper.

  5. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    International Nuclear Information System (INIS)

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine

  6. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    Energy Technology Data Exchange (ETDEWEB)

    May, J.C. E-mail: may@cber.fda.gov; Rey, L. E-mail: louis.rey@bluewin.ch; Lee, C.-J.; Arciniega, Juan

    2004-10-01

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

  7. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    Science.gov (United States)

    May, J. C.; Rey, L.; Lee, Chi-Jen; Arciniega, Juan

    2004-09-01

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

  8. Thermoluminescence (TL) Analysis and Fading Studies of Naturally Occurring Salt Irradiated by 500 mGy Gamma Rays

    Science.gov (United States)

    Tiwari, Ramesh Chandra; Pau, Kham Suan

    2011-10-01

    The aim of the present study was to investigate the potential of the naturally occurring salt for the dosimetry purposes, using TL. The fine powder samples (20 mg) were irradiated by γ- rays from 500 mGy to 2500 mGy by using Theratron-780C Cobalt-60 source, however, this paper discusses about 500 mGy only. The TL glow curve peak parameters were studied by using Chen's peak shape equation. TL glow curves were compared with fitted curves using glow curve deconvolution (GCD) method by using Kitis expression. The kinetic parameter values (E, b and s) so calculated, are in good agreement with those available in literature. The calculated energy values were also verified by using various heating rate (VHR) method. χ2 test and figure of merit (FOM) calculation was done to accept the goodness of fit between the curves. Fading studies of the sample showed a good fitting between the curves. The analysis suggests that natural salt should be considered for dosimetry purposes.

  9. Poly(acrylic acid)/polyethylene glycol hygrogel prepared by using gamma-ray irradiation for mucosa adhesion

    Science.gov (United States)

    Nho, Young-Chang; Park, Jong-Seok; Shin, Jung-Woong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Gwon, Hui-Jeong; Khil, Myung-Seob; Lee, Deok-Won; Ahn, Sung-Jun

    2015-01-01

    A buccal delivery system provides a much milder environment for drug delivery compared to an oral delivery which presents a hostile environment for drugs, especially proteins and polypeptides, owing to acid hydrolysis. Local delivery in an oral cavity has particular applications in the treatment of toothaches, periodontal disease, and bacterial infections. Poly(acrylic acid) (PAA)-based hydrogels prepared using a chemical initiator have been attempted for a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, PAA and polyethylene glycol (PEG) were selected to prepare using a radiation process a bioadhesive hydrogel for adhesion to mucosal surfaces. PAA and PEG were dissolved in purified water to prepare a homogeneous PAA/PEG solution, and the solution was then irradiated using an electron beam at dose up to 70 kGy to make the hydrogels. Their physical properties, such as gel percent, swelling percent, and adhesive strength to mucosal surfaces, were investigated. In this experiment, various amounts of PEG were incorporated into the PAA to enhance the mucoadhesive property of the hydrogels. The effect of the molecular weight of PEG on the mucoadhesion was also examined.

  10. Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes

    International Nuclear Information System (INIS)

    Terrestrial gamma-ray flashes (TGFs) are very short bursts of high-energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mini-Calorimeter. We detect 8 TGFs with gamma-ray photons of energies above 20 MeV localized by the AGILE gamma-ray imager with an accuracy of ?5-10 deg. at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the subsatellite point than 400 km. Considering that our gamma rays reach the AGILE satellite at 540 km altitude with limited scattering or attenuation, our measurements provide the first precise direct localization of TGFs from space.

  11. Cellular response to low Gamma-ray doses

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares A, E.; Vega C, H.R.; Leon, L.C. de [Unidades Academicas de Estudios Nucleares, Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico)]. E-mail: emanz@cantera.reduaz.mx; Rebolledo D, O.; Radillo J, F. [Facultad de Ciencias Biologicas y Agropecuarias de la Universidad de Colima, Colima (Mexico)

    2002-07-01

    Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

  12. Cellular response to low Gamma-ray doses

    International Nuclear Information System (INIS)

    Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

  13. Age and sex dependence in tumorigenesis in mice by continuous low-dose-rate gamma-ray whole-body irradiation

    International Nuclear Information System (INIS)

    We investigated the dependency of sex and age in mice in the induction of neoplasms by gamma-rays from cesium-137 at a low dose rate of 0.375Gy/22h/day. Thymic lymphomas occurred significantly at the same incidence in both sexes, and more frequently when younger mice were exposed to radiation. Strain C57BL/6J mice were divided into 8 groups, which were whole-body irradiated with a total dose of 39Gy for 105 days each. The exposure was begun at 28 days of age (male:AM1, female:AF1), and then stepwise increasing the starting age by 105 days, i.e., from 133 days (AM2 and AF2), from 238 days (AM3 and AF3), and from 343 days (AM4 and AF4), respectively. Unirradiated mice served as control (UM and UF). The incidence of thymic lymphomas was about 60 % in AM1, AM2, AF1 and AF2, 40 % in AM3 and AF3 and 20 % in AF4 and AF4, demonstrating no sex dependency, but a distinct age dependency, for lymphomogenesis. It was proven that mice showed a tendency to become less susceptible to radiation induced thymic lymphoma with increasing age. Concomitantly, life-shortening also was caused, and the greater the degree of life-shortening was, the younger the mice were the start of exposure. Life-shortening was attributed to thymic lymphoma, and hemorrhage and infectious diseases due to the depletion of bone marrow cells. (author)

  14. Thermo-mechanical characteristics of UV-irradiated polyurethane elastomers extended with ?, ?-alkane diols

    International Nuclear Information System (INIS)

    A series of polyurethane elastomers were prepared by the reaction of poly ?-caprolactone and 4,4'-diphenylmethane diisocyanate. The prepolymer was extended using ?, ?-alkane diols as chain extenders having 2-10 methylene units in their structure. The synthesized samples were irradiated for 50, 100 and 200 h in an ultra violet (UV) exposure unit. Modifications in the chemical structure before and after irradiation were characterized using Fourier Transform Infrared spectroscopy. The thermal and mechanical properties were affected by the ultra violet irradiation time and the number of methylene units in the chain extenders. The experimental results indicated that the morphological structure changed during irradiation as a consequence of hard segment and soft segment degradation.

  15. Influence of the molecular modifications on the properties of EPDM elastomers under irradiation

    International Nuclear Information System (INIS)

    The degradation of the mechanical behaviour of EPDM elastomers used as cable insulation materials has been investigated by mechanical spectroscopy and tensile tests for different formulations: unvulcanised EPDM, vulcanised and stabilised elastomer with an antioxidant. In all cases, ?-irradiation of EPDM under oxygen leads to a reduction of the molecular mobility indicated by the shift of the glass transition relaxation temperature towards higher temperatures. Moreover, the molecular flow occurring above Tg is suppressed after irradiation for the unvulcanised EPDM providing evidence of cross-linking. The competition between cross-linking and chain scissions is shown by the decrease of the storage modulus above the crystallites melting temperature (?40 deg. C) at doses larger than 100 kGy. A strong increase of the Young modulus and reduction of the elongation at break of the non-vulcanised EPDM becoming more brittle are shown by stress/strain characterisations performed at 80 deg. C. At the opposite vulcanised EPDM exhibits higher elongation at break after crystallites melting. This evolution is interpreted by the competition between cross-linking and chain scissions, being hindered by the crystallites at room temperature. The intrinsic irradiation effects can be isolated after crystallite melting. The reduction of the molecular mobility can be explained by a chemi-crystallisation process assisted by chain scissions, leading to a more rigid phase upon irradiation

  16. Influence of the molecular modifications on the properties of EPDM elastomers under irradiation

    Science.gov (United States)

    Davenas, J.; Stevenson, I.; Celette, N.; Vigier, G.; David, L.

    2003-08-01

    The degradation of the mechanical behaviour of EPDM elastomers used as cable insulation materials has been investigated by mechanical spectroscopy and tensile tests for different formulations: unvulcanised EPDM, vulcanised and stabilised elastomer with an antioxidant. In all cases, ?-irradiation of EPDM under oxygen leads to a reduction of the molecular mobility indicated by the shift of the glass transition relaxation temperature towards higher temperatures. Moreover, the molecular flow occurring above Tg is suppressed after irradiation for the unvulcanised EPDM providing evidence of cross-linking. The competition between cross-linking and chain scissions is shown by the decrease of the storage modulus above the crystallites melting temperature (40 C) at doses larger than 100 kGy. A strong increase of the Young modulus and reduction of the elongation at break of the non-vulcanised EPDM becoming more brittle are shown by stress/strain characterisations performed at 80 C. At the opposite vulcanised EPDM exhibits higher elongation at break after crystallites melting. This evolution is interpreted by the competition between cross-linking and chain scissions, being hindered by the crystallites at room temperature. The intrinsic irradiation effects can be isolated after crystallite melting. The reduction of the molecular mobility can be explained by a chemi-crystallisation process assisted by chain scissions, leading to a more rigid phase upon irradiation.

  17. Role of the microstructure in the neutron and gamma-ray irradiation stability of solution-derived Ba0.5Sr0.5TiO3 thin films

    International Nuclear Information System (INIS)

    The influence of neutron and gamma-ray irradiation on the kilohertz- and microwave-range dielectric properties of polycrystalline Ba0.5Sr0.5TiO3 thin films was investigated. The solution-derived films were prepared on polycrystalline alumina substrates and their microstructures were controlled through the deposition procedure and the annealing temperature. The approximately 600 nm-thick films were either quite porous, consisting of fine, ?35 nm equiaxed grains, or dense, with predominantly columnar grains with an in-plane size of ?100 nm. Much thinner, ?170 nm-thick films with a dense columnar microstructure, and an approximately 70 nm in-plane grain size were also prepared. The irradiation doses were 1.1 1014 n cm?2 and 167 kGy for the neutrons and gamma rays, respectively. No microstructural changes were observed in the films. However, the film with the granular microstructure showed much reduced microwave dielectric properties after the neutron irradiation. The films with the columnar microstructure are less sensitive to both types of irradiation, with the thicker films showing decreased values of the extrinsic dielectric losses. The effect is discussed in terms of the influence of microstructural features, such as grain boundaries, pores and microcracks, as well as crystal-lattice defects on the irradiation-damage accumulation rate, concluding that the microstructure of the pristine films is decisive for the irradiation hardness of ferroelectric thin films used for microwave applications

  18. Gamma-Ray Burst Lines

    OpenAIRE

    Briggs, Michael S.

    1999-01-01

    The evidence for spectral features in gamma-ray bursts is summarized. As a guide for evaluating the evidence, the properties of gamma-ray detectors and the methods of analyzing gamma-ray spectra are reviewed. In the 1980's, observations indicated that absorption features below 100 keV were present in a large fraction of bright gamma-ray bursts. There were also reports of emission features around 400 keV. During the 1990's the situation has become much less clear. A small fra...

  19. Surface treatment of poly(ethylene terephthalate) by gamma-ray induced graft copolymerization of methyl acrylate and its toughening effect on poly(ethylene terephthalate)/elastomer blend

    International Nuclear Information System (INIS)

    To improve the compatibility between ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (E-MA-GMA) elastomer and poly(ethylene terephthalate) (PET), thereby enhance the toughening effect of E-MA-GMA on PET, γ-radiation-induced graft copolymerization technique was used to graft methyl acrylate (MA) monomer onto PET. The produced PET-g-PMA copolymer can be used as a self-compatibilizer in PET/E-MA-GMA blend since the copolymer contains the same segments, respectively, with PET and E-MA-GMA. The impact strength of PET/E-MA-GMA blend increased nearly by 30% in the presence of less than 0.1 wt% PET-g-PMA compared with that of the neat PET/elastomer blend, without loss of the tensile strength of the blends. This work proposed a potential application of radiation-induced grafting copolymerization technique on the in-situ compatibilization of PET/elastomer blends so as to improve the integral mechanical properties of PET based engineering plastic. - Highlights: • PMA was grafted onto PET resins by γ-ray radiation-induced copolymerization. • The obtained PET-g-PMA can improve the compatibility between PET and E-MA-GMA. • A small amount of PET-g-PMA can enhance the impact strength of PET/E-MA-GMA blend

  20. Reaction mechanisms in ? irradiated high surface silica-elastomer systems

    International Nuclear Information System (INIS)

    Complete text of publication follows. In this work the mechanism of the ?-ray induced vulcanization of the binary systems consisting of styrene butadiene rubber (SBR; 30% stryrene, 25% vinyl units) and high surface silica (160-1000 m2/g) are investigated by matrix EPR spectroscopy, ATR-FTIR and by measuring the crosslinking kinetics. The experiments have dealt with pristine silica, silica modified by radiation grafting of polybutadiene olygomers (SiO2/PB) and the SBR compounds containing 30-40% of pristine or modified silica. The irradiation under vacuum of the pristine silica gives rise to thermally unstable species which decay at very low temperature, below 180 K. When the SBR/silica compounds are irradiated, in addition to the SBR radicals, also SBR chain radicals is greatly enhanced when using silica coated with polybutadiene olygomers bearing high (25-45%) vinyl double bond content. The rationale of such observation is that the species generated within the bulk of the silica particles migrate to the surface where are scavenged by the vinyl double bonds of the absorbed chains. It is thus assessed that the direct radiolysis of silica plays an active role in the radiation vulcanization process by promoting the formation of silica-rubber chemical links which are of key importance in the reinforcement mechanism. The crosslinking kinetics were found to be coherent with the above observation showing that the crosslinks yield vs dose ratios increase in the order: pure SBR 2 2(PB).

  1. An Elementary Treatment of Gamma-Ray Heating and Gamma-Ray Dosage in Inhomogeneous Reactors

    International Nuclear Information System (INIS)

    An analysis is made of the heat produced by the absorption of gamma rays in a sample placed into a reactor. It is clearly shown that enormous local (space) variations in gamma flux exist in current reactors. An application to the Hanford reactors is treated in some detail. Although the estimates obtained may be good to but a factor of two, it is clearly shown that in most cases the major portion of the heating is due to (n, ?) reactions within the sample itself, and in some cases to the gamma rays generated in liners and cans, and not from the gamma rays generated in fission, nor from the moderator. Some implications of these results are discussed, among the most important being their application to radiation chemistry in reactors. Several mathematical results for absorption and generation of gamma rays in various bodies which should be useful in estimating dosage rates for samples irradiated in reactors are given (Appendix II). A method for making the calculations for an arbitrary absorption law are given (Appendix III). This method may be used with the true absorption law for gamma rays or even for the calculation of the absorption of the energy of particles possessing a range law of absorption, e.g., ?-rays or protons.

  2. Gamma ray induced chlorophyll mutations in linseed

    International Nuclear Information System (INIS)

    Different types of mutants were obtained in different varieties of linseed after exposure to gamma rays. An overall increase in mutation percentage with an increase in dose of irradiation was apparent. As compared to normal in all the mutants, days to flowering, days to maturity, number of non-bearing tillers per plant and number of leaves per cm. on the main tiller increased considerably, while plant height, number of capsules per plant and number of seeds per capsule were reduced drastically. (author)

  3. Airborne gamma-ray spectrometry

    DEFF Research Database (Denmark)

    Hovgaard, Jens

    A new method - Noise Adjusted Singular Value Decomposition, NASVD - for processing gamma-ray spectra has been developed as part of a Ph.D. project. By using this technique one is able to decompose a large set of data - for example from airborne gamma-ray surveys - into a few spectral components. By...

  4. High energy gamma ray astronomy

    Science.gov (United States)

    Fichtel, Carl E.

    1987-01-01

    High energy gamma ray astronomy has evolved with the space age. Nonexistent twenty-five years ago, there is now a general sketch of the gamma ray sky which should develop into a detailed picture with the results expected to be forthcoming over the next decade. The galactic plane is the dominant feature of the gamma ray sky, the longitude and latitude distribution being generally correlated with galactic structural features including the spiral arms. Two molecular clouds were already seen. Two of the three strongest gamma ray sources are pulsars. The highly variable X-ray source Cygnus X-3 was seen at one time, but not another in the 100 MeV region, and it was also observed at very high energies. Beyond the Milky Way Galaxy, there is seen a diffuse radiation, whose origin remains uncertain, as well as at least one quasar, 3C 273. Looking to the future, the satellite opportunities for high energy gamma ray astronomy in the near term are the GAMMA-I planned to be launched in late 1987 and the Gamma Ray Observatory, scheduled for launch in 1990. The Gamma Ray Observatory will carry a total of four instruments covering the entire energy range from 30,000 eV to 3 x 10 to the 10th eV with over an order of magnitude increase in sensitivity relative to previous satellite instruments.

  5. High energy gamma ray astronomy

    International Nuclear Information System (INIS)

    High energy gamma ray astronomy has evolved with the space age. Nonexistent twenty-five years ago, there is now a general sketch of the gamma ray sky which should develop into a detailed picture with the results expected to be forthcoming over the next decade. The galactic plane is the dominant feature of the gamma ray sky, the longitude and latitude distribution being generally correlated with galactic structural features including the spiral arms. Two molecular clouds were already seen. Two of the three strongest gamma ray sources are pulsars. The highly variable x ray source Cygnus X-3 was seen at one time, but not another in the 100 MeV region, and it was also observed at very high energies. Beyond the Milky Way Galaxy, there is seen a diffuse radiation, whose origin remains uncertain, as well as at least one quasar, 3C 273. Looking to the future, the satellite opportunities for high energy gamma ray astronomy in the near term are the GAMMA-I planned to be launched in late 1987 and the Gamma Ray Observatory, scheduled for launch in 1990. The Gamma Ray Observatory will carry a total of four instruments covering the entire energy range from 30,000 eV to 3 x 10 to the 10th eV with over an order of magnitude increase in sensitivity relative to previous satellite instruments

  6. Estimating. gamma. -rays dose using computer

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rawi, A.M.; Muslih, R.M.; Al-Harithy, R.S. (Baghdad Univ. (Iraq). Coll. of Education for Women)

    1990-01-01

    When gum arabic is exposed to {gamma}-rays, a change in its reflection and absorption ability for the different wave lengths is obtained. This change is used for estimating the absorbed {gamma}-rays directly. In the present work we are not concerned with the type of components that are chemically formed as emphasis will only be put on the physical changes. The physical state is taken as a potential chemical change since a molecular damage is accumulated as a result of the dose absorbed. The fortran IV data General (Nova 3) designed for estimating colour measurements was connected to a spectrophotometer that enables measuring the changes in both absorbing and reflecting or even diffusing of light through irradiated materials. (author).

  7. Applied gamma-ray spectrometry

    CERN Document Server

    Dams, R; Crouthamel, Carl E

    1970-01-01

    Applied Gamma-Ray Spectrometry covers real life application of the gamma-ray and the devices used in their experimental studies. This book is organized into 9 chapters, and starts with discussions of the various decay processes, the possible interaction mechanisms of gamma radiation with matter, and the intrinsic and extrinsic variables, which affect the observed gamma-ray and X-ray spectra. The subsequent chapters deal with the properties and fabrication of scintillation detectors, semiconductor detectors, and proportional gas counters. These chapters present some of the most widely utilized

  8. Cloaked Gamma Ray Bursts

    CERN Document Server

    Eichler, David

    2014-01-01

    It is suggested that many $\\gamma$-ray bursts (GRBs) are cloaked by an ultra-relativistic baryonic shell that has high optical depth when the photons are manufactured. Such a shell would not fully block photons reflected or emitted from its inner surface, because the radial velocity of the photons can be less than that of the shell. This avoids the standard problem associated with GRBs that the thermal component should be produced where the flow is still obscured by high optical depth. The radiation that escapes high optical depth obeys the Amati relation. Observational implications may include a) anomalously high ratios of afterglow to prompt emission, such as may have been the case in the recently discovered PTF 11agg, and b) ultrahigh-energy neutrino pulses that are non-coincident with detectable GRB. It is suggested that GRB 090510, a short, very hard GRB with very little afterglow, was an {\\it exposed} GRB, in contrast to those cloaked by baryonic shells. \\end{abstract}

  9. Surface characteristics of UV-irradiated polyurethane elastomers extended with ?, ?-alkane diols

    International Nuclear Information System (INIS)

    Polyurethane elastomers (PUEs) based on 4,4'-diphenylmethane diisocyanate (MDI), poly (?-caprolactone) (PCL) and extended with series of chain extender (CE) were synthesized via two step polymerization technique. The synthesized samples were irradiated for 50, 100 and 200 h in an UV exposure unit as such the spectral distribution of the light is good match for terrestrial solar radiation. The modifications in the chemical structures of the PU before and after irradiation were characterized using Fourier transform infrared (FT-IR) technique. The effect of irradiation time and chain extenders length on surface properties were studied and investigated. Photo-oxidation of PU surface leads to fast increase in surface free energy and its polar component. Simultaneously, the work of water adhesion to polymer increases significantly during UV-irradiation. The higher changes in surface properties, observed by water absorption (%), equilibrium degree of swelling, as well as monitored by ATR-FT-IR and contact angle measurement, were found for the PU samples extended with higher number of methylene unit and irradiation time

  10. Surface characteristics of UV-irradiated polyurethane elastomers extended with {alpha}, {omega}-alkane diols

    Energy Technology Data Exchange (ETDEWEB)

    Zia, Khalid Mahmood [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Bhatti, Ijaz Ahmad [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan)], E-mail: ijazchem@yahoo.com; Barikani, Mehdi [Iran Polymers and Petrochemicals Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of); Zuber, Mohammad [Department of Textile Chemistry, National Textile University Faisalabad (Pakistan); Islam-ud-Din [Department of Mathematics and Statistics, University of Agriculture, Faisalabad 38040 (Pakistan)

    2008-08-30

    Polyurethane elastomers (PUEs) based on 4,4'-diphenylmethane diisocyanate (MDI), poly ({epsilon}-caprolactone) (PCL) and extended with series of chain extender (CE) were synthesized via two step polymerization technique. The synthesized samples were irradiated for 50, 100 and 200 h in an UV exposure unit as such the spectral distribution of the light is good match for terrestrial solar radiation. The modifications in the chemical structures of the PU before and after irradiation were characterized using Fourier transform infrared (FT-IR) technique. The effect of irradiation time and chain extenders length on surface properties were studied and investigated. Photo-oxidation of PU surface leads to fast increase in surface free energy and its polar component. Simultaneously, the work of water adhesion to polymer increases significantly during UV-irradiation. The higher changes in surface properties, observed by water absorption (%), equilibrium degree of swelling, as well as monitored by ATR-FT-IR and contact angle measurement, were found for the PU samples extended with higher number of methylene unit and irradiation time.

  11. Gamma rays at airplane altitudes

    International Nuclear Information System (INIS)

    An examination of the gamma ray flux above 1 TeV in the atmosphere is needed to better understand the anomalous showers from point sources. Suggestions are made for future experiments on board airplanes

  12. Directional detector of gamma rays

    International Nuclear Information System (INIS)

    A directional detector of gamma rays comprises a strip of an electrical conductor of high atomic number backed with a strip of a second electrical conductor of low atomic number. These elements are enclosed within an electrical conductor that establishes an electrical ground, maintains a vacuum enclosure and screens out low-energy gamma rays. The detector exhibits a directional sensitivity marked by an increased output in the favored direction by a factor of ten over the output in the unfavored direction

  13. Gamma-ray spectrometer experiment

    Science.gov (United States)

    Arnold, J. R.; Peterson, L. E.; Metzger, A. E.; Trombka, J. I.

    1972-01-01

    The experiments in gamma-ray spectrometry to determine the geochemical composition of the lunar surface are reported. The theory is discussed of discrete energy lines of natural radioactivity, and the lines resulting from the bombardment of the lunar surface by high energy cosmic rays. The gamma-ray spectrometer used in lunar orbit and during transearth coast is described, and a preliminary analysis of the results is presented.

  14. Experimental investigations into the effects of irradiation with neutron and gamma rays on the immune system, as demonstrated at the model of immunity of Salmonella typhimurium on the mouse

    International Nuclear Information System (INIS)

    Mice were irradiated with neutron and gamma rays (with a dose of 200 rad respectively 300 rad). Either 24 hours before or after the irradiation the mice were vaccinated and revaccinated with a Salmonella typhimurium vaccine. By ELISA, IHA and BTZD-test specific antibodies against Salmonella typhimurium could be found. The 200 rad irradiated animals had a lower increase in the formation of antibodies compared with mice not irradiated, if the irradiation was applied before the immunisation. On the 300 rad irradiated animals a reduction of the formation of the antibodies could be observed, too. The antibody titres, however, were higher and an earlier increase of the number of the antibodies was found in comparison with the 200 rad irradiated animals. A second antigene application after 7 days and an irradiation after the first respectively the second immunisation gave no noticeable proof of immune suppression. In our tests it was found out, that for the definition of the antibody titres of the sera the ELISA and the IHA had been more sensitive than the BTZD-test. (orig./MG)

  15. Catalogue of gamma rays from radionuclides

    International Nuclear Information System (INIS)

    A catalogue of almost 11000 gamma rays is presented. The gamma rays are sorted by energy. In addition to the gamma-ray intensity per 100 decays of the parent, the decay half-life and associated gamma rays are given. All data are from a computer processing of a recent ENSDF file. (author)

  16. Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy; Biodegradacao de poliuretano derivado de oleo vegetal irradiado com raios gama 25 kGy e 100 kGy

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Antonia M. dos, E-mail: amsantos@rc.unesp.br [Universidade Estadual Paulista - Unesp, Rio Claro, SP (Brazil); Claro Neto, Salvador [Universidade de Sao Paulo - USP, Campus de Sao Carlos, SP (Brazil); Azevedo, Elaine C. de [Universidade Federal do Parana, Campus de Curitiba, PR (Brazil)

    2011-07-01

    The environment requires polymers that can be degraded by the action of microorganisms. In this work was studied the biodegradation of polyurethane samples derived from vegetable oil (castor oil), which were irradiated with gamma rays 25 kGy and 100 kGy compared with the same polyurethane without being irradiated. Biodegradation of polyurethane was carried out in culture medium containing the fungus Aspergillus niger by 146 days and the result was evaluated using the technique of thermogravimetric analysis, where there was a change of behavior of the curves TGA / DTG occurred indicating that chemical modifications of molecules present in the structure of the polymer chain, thus confirming that the material has undergone the action of microorganisms. (author)

  17. Microstructural study of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x}/Ag samples irradiated with {sup 60}Co {gamma} rays at high doses

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, R. [Programa de Postgrado en Fisica de Materiales, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Apartado Postal 2681, CP 22800, Ensenada, BC (Mexico); Galvan, D.H. [CECIMAC-UNAM, Apartado Postal 2681, CP 22800, Ensenada, BC (Mexico); Adem, E. [Instituto de Fisica-UNAM, Apartado Postal 20-364, CP 01000, Mexico DF (Mexico); Bartolo-Perez, P. [CINVESTAV-IPN Unidad Merida, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Maple, M.B. [Physics Department and Institute for Pure and Applied Physical Sciences, La Jolla, CA (United States)

    1998-06-01

    We have investigated the damage induced by irradiation in Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-x} silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy {gamma} irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (T{sub c}) and zero-resistance temperature (T{sub 0}). After irradiation, T{sub c} decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T{sub 0} between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, J{sub c} decreased because of the weak-link breakage induced by high doses of {gamma} rays. (author)

  18. Effects of electron- and/or gamma-irradiation upon the optical behavior of transparent MgAl{sub 2}O{sub 4} ceramics: Different color centers induced by electron-beam and {gamma}-ray

    Energy Technology Data Exchange (ETDEWEB)

    He Jie; Lin Libin E-mail: libinlin@hotmail.com; Lu Tiecheng; Wang Pen

    2002-05-01

    Samples of transparent MgAl{sub 2}O{sub 4} ceramics were irradiated by electron beams with energy of 1.7 MeV and fluence from 1x10{sup 13} to 6x10{sup 16} cm{sup -2} and {gamma}-ray with dose from 0.1 to 3500 kGy, respectively. After irradiation, the samples were annealed at different temperatures from 250 to 550 deg. C. Transmittance spectroscopy and positron annihilation technique has been used to examine the behavior and the nature of defects in the spinel produced by irradiation and annealing. The results of our study indicate that two absorption bands are produced after 10{sup 16} cm{sup -2} electron-irradiated sample and one absorption band is produced in {gamma}-irradiated ones. The absorption bands produced after electron-irradiation are destroyed by isochronal annealing. F centers aggregates during annealing. The F center absorption band centered at 273 nm shifts to 210 nm. After {gamma}-irradiation there are few displacement of O{sup 2-}, the voids exist in grain boundary split into monovacancies. Isochronal annealing destroys V type center absorption band in the sample. With increase of annealing temperature, cation vacancies aggregate.

  19. A neutron capture gamma-ray facility

    International Nuclear Information System (INIS)

    A neutron capture gamma-ray facility was constructed for prompt gamma-ray spectrometry, and its characteristics were measured. In the facility, a neutron beam is extracted from the H-6 horizontal experimental hole of Japan Research Reactor No.3, JAERI, and a target outside the reactor is irradiated by the beam. Thermal neutron flux at the target position was 8.0 x 107 n/cm2.s and the cadmium ratio (Au) was 21. Characteristics of a Ge gamma-ray spectrometer using a 7 in. diameter x 8 in. length guard NaI (Tl) detector were measured for 3 modes, single, Compton (escape) suppressed and pair, with neutron capture gamma-rays from nitrogen, chromium etc. Characteristics were: (1) in single spectrometer, full-energy peak efficiency 2.3 x 10-5 (1 MeV), 4.6 x 10-6 (5 MeV) and 1.25 x 10-6 (10 MeV); (2) in Compton (escape) suppressed spectrometer, Compton suppression factor 3.5 (1-2 MeV), 5.1 (3-5 MeV) and 5.5 (6-8 MeV), and escape suppression factor 2.57 +- 0.2 (single) and 8.34 +- 1.2 (double); (3) in pair spectrometer, detection efficiency 4.5 x 10-7 (3 MeV), 6.5 x 10-7 (4 MeV), 7.1 x 10-7 (5 MeV) and 7.3 x 10-7 (5.5-10 MeV). Lower detection limits in determination of boron, cadmium and gadolinium by Compton suppressed spectrometry of prompt gamma-rays were evaluated on the basis of the experimental data. The limits under the conditions of 2 g aqueous solution, standard error 10% and counting time 1000 s were 9.0 ?g for B, 12.3 ?g for Cd and 2.9 ?g for Gd. (author)

  20. Terrestrial gamma-ray flashes

    Energy Technology Data Exchange (ETDEWEB)

    Marisaldi, Martino, E-mail: marisaldi@iasfbo.inaf.it [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Fuschino, Fabio; Labanti, Claudio [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Tavani, Marco [INAF-IASF Roma, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Argan, Andrea [INAF, Viale del Parco Mellini 84, 00136 Roma (Italy); Del Monte, Ettore [INAF-IASF Roma, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Longo, Francesco; Barbiellini, Guido [Dipartimento di Fisica Universit di Trieste and INFN Trieste, via A. Valerio 2, I-34127 Trieste (Italy); Giuliani, Andrea [INAF-IASF Milano, Via Bassini 15, I-20133 Milano (Italy); Trois, Alessio [INAF Osservatorio Astronomico di Cagliari, loc. Poggio dei Pini, strada 54, I-09012 Capoterra (Italy); Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

    2013-08-21

    Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models.

  1. Terrestrial gamma-ray flashes

    International Nuclear Information System (INIS)

    Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models

  2. The Gamma-Ray Observatory

    Science.gov (United States)

    Kniffen, Donald A.

    1989-01-01

    The scientific goals and the design of the NASA Gamma-Ray Observatory (GRO), planned for launch in mid-1990, are described together with the experiments to be performed on the GRO mission and the instruments to be flown on the Observatory. GRO contains a complement of four instruments to span the spectrum from 0.03 to 20,000 MeV in energy, three of which are optimized to make gamma-ray observations using either the photoelectric effect, the Compton scatter, or the pair production processes; the fourth instrument is optimized for high-sensitivity observations of transient events and time-variable sources. The instruments are the Oriented Scintillation Spectrometer Experiment, the Compton Telescope, the Energetic Gamma-Ray Experiment Telescope, and the Burst and Transient Source Experiment.

  3. The Gamma-ray Sky with Fermi

    Science.gov (United States)

    Thompson, David

    2012-01-01

    Gamma rays reveal extreme, nonthermal conditions in the Universe. The Fermi Gamma-ray Space Telescope has been exploring the gamma-ray sky for more than four years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge gamma-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

  4. Gamma-ray Imaging Methods

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, K; Mihailescu, L; Nelson, K; Valentine, J; Wright, D

    2006-10-05

    In this document we discuss specific implementations for gamma-ray imaging instruments including the principle of operation and describe systems which have been built and demonstrated as well as systems currently under development. There are several fundamentally different technologies each with specific operational requirements and performance trade offs. We provide an overview of the different gamma-ray imaging techniques and briefly discuss challenges and limitations associated with each modality (in the appendix we give detailed descriptions of specific implementations for many of these technologies). In Section 3 we summarize the performance and operational aspects in tabular form as an aid for comparing technologies and mapping technologies to potential applications.

  5. Combination effect of gamma rays, EMS and the storage before irradiation on some characteristics of M1 and M2 plants of bread wheat triticum aestivum L.(Cv. ajeeba)

    International Nuclear Information System (INIS)

    Three samples of bread-wheat CV.Ajeeba stored under baghdad prevailing room conditions since 1988,1978 and 1983 wereirradiation with gamma rays (15 Krad).They were then treated with the chemical mutagen(EMS).Seeds were sown in the field during the cultivation seasons of 1983-1985.The effects of gamma radiation,EMS,the storage periods and their interaction on some developmental stages of M1 plants were statistically significant.However,no differences were observed among M2 plants.The greatest number of variants were found among M2 plants that had originated from seeds stored since 1968,irradiated and treated with EMS.(3 tabs., 18 refs.)

  6. TL detectors for gamma ray dose measurements in criticality accidents

    International Nuclear Information System (INIS)

    Determination of gamma ray dose in mixed neutron + gamma ray fields is still a demanding task. Dosemeters used for gamma ray dosimetry are usually in some extent sensitive to neutrons and their response variations depend on neutron energy i.e., on neutron spectra. Besides, it is necessary to take into account the energy dependence of dosemeter responses to gamma rays. In this work, several types of thermoluminescent detectors (TLD) placed in different holders used for gamma ray dose determination in the mixed fields were examined. Dosemeters were from three different institutions: Ruder Boskovic Inst. (RBI), Croatia, Jozef Stefan Inst. (JSI), Slovenia and Autoridad Regulatoria Nuclear (ARN), Argentina. All dosemeters were irradiated during the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002. Three accidental scenarios were reproduced and in each irradiation the dosemeters were exposed placed on the front of phantom and 'free in air'. Following types of TLDs were used: 7LiF (TLD-700), CaF2:Mn and Al2O3:Mg,Y - all from RBI; CaF2:Mn from JSI and 7LiF (TLD-700) from ARN. Reported doses were compared with the reference values as well as with the values obtained from the results of all participants. The results show satisfactory agreement with other dosimetry systems used in the Intercomparison. The influence of different types of holders and applied corrections of dosemeters' readings are discussed. (authors)

  7. Property of laser Compton scattering gamma-ray beam and application

    International Nuclear Information System (INIS)

    Laser Compton scattering gamma-ray beam source was developed on BL01 of NewSUBARU synchrotron radiation facility. The gamma-ray beams were used for application experiments, a nuclear physics research, a nondestructive inspection of thick material, a magnet Compton scattering measurements, and nuclear transmutation research. New gamma-ray irradiation hutch was started to use. Gamma-ray photon energy of up to 76 MeV is available. Expected flux of quasi-monochromatic gamma-ray (16.7 MeV, ΔE/E∼5%) is more than 106 γ/s using 35W Nd laser and 300 mA electron current. Recently, new electron energy value operation of NewSUBARU was tested. The electron energy of 0.55 GeV to 1.47 GeV were used for changing energy of quasi-monochromatic gamma-ray beam. (author)

  8. Short duration gamma ray bursts

    Indian Academy of Sciences (India)

    Patrick Das Gupta

    2004-10-01

    After a short review of gamma ray bursts (GRBs), we discuss the physical implications of strong statistical correlations seen among some of the parameters of short duration bursts ($T_{90}$ < 2 s). Finally, we conclude with a brief sketch of a new unified model for long and short GRBs.

  9. Novae in gamma-rays

    CERN Document Server

    Hernanz, M

    2013-01-01

    Classical novae produce radioactive nuclei which are emitters of gamma-rays in the MeV range. Some examples are the lines at 478 and 1275 keV (from 7Be and 22Na) and the positron-electron annihilation emission (511 keV line and a continuum below this energy, with a cut-off at 20-30 keV). The analysis of gamma-ray spectra and light curves is a potential unique and powerful tool both to trace the corresponding isotopes and to give insights on the properties of the expanding envelope determining its transparency. Another possible origin of gamma-rays is the acceleration of particles up to very high energies, so that either neutral pions or inverse Compton processes produce gamma-rays of energies larger than 100 MeV. MeV photons during nova explosions have not been detected yet, although several attempts have been made in the last decades; on the other hand, GeV photons from novae have been detected in some particular novae, in symbiotic binaries, where the companion is a red giant with a wind, instead of a main ...

  10. High energy gamma ray observations

    Science.gov (United States)

    Fichtel, Carl E.

    1992-01-01

    Since the trajectories of astrophysical charged particles are bent by magnetic fields and normally curl many times before their detection, their origin may not be inferred from their directions as is the case with photons. Fortunately, charged particles reveal their presence through interactions in many instances leading to high-energy gamma rays. Bremsstrahlung, Compton, synchrotron, and curvature radiation all generally have a monotonically decreasing energy spectra reflecting that of the parent particles, whereas nucleon-nucleon radiation has a maximum at about 70 MeV reflecting the nature of the interaction process. Gamma radiation has been seen coming from neutron stars in pulses with the same period as the radio pulsar. Solar gamma rays also have been seen, as have short bursts of gamma rays whose origin remain a mystery. Galactic diffuse gamma radiation reveals the distribution of cosmic rays in our Galaxy. Beyond our Galaxy, active galaxies are seen in gamma rays implying a huge energy in the form of cosmic rays to be present there. The Optically Violent Variable quasar 3C 279 is particularly astounding. During an active state 3C 279 was seen to be emitting approximately 10 exp 48 erg/s if its radiation is isotropic.

  11. Neutron interrogation system using high gamma ray signature to detect contraband special nuclear materials in cargo

    Science.gov (United States)

    Slaughter, Dennis R. (Oakland, CA); Pohl, Bertram A. (Berkeley, CA); Dougan, Arden D. (San Ramon, CA); Bernstein, Adam (Palo Alto, CA); Prussin, Stanley G. (Kensington, CA); Norman, Eric B. (Oakland, CA)

    2008-04-15

    A system for inspecting cargo for the presence of special nuclear material. The cargo is irradiated with neutrons. The neutrons produce fission products in the special nuclear material which generate gamma rays. The gamma rays are detecting indicating the presence of the special nuclear material.

  12. Gamma rays for Ephestia Kuehniella control

    International Nuclear Information System (INIS)

    Trials were undertaken to establish gamma irradiation action on the various developmental stages of Ephestia Kuehniella. It was found that its eggs perished 100% when irradiated with a dose of 6 krad. Mortality of young larvae irradiated with gamma ray dose of 4-22 krad accounted for 23.91-43.64% during the first 10 days, and for 53.9-95% after 50 days. Irradiation with 20-22 krad intensity resulted in 100% mortality 60 days post irradiation. In the case of adult larvae, 8.8-40.57% were killed 10 days post irradiation and 53.98-100% - after 50 days. Some larvae could survive for 90 days post 8-12 krad irradiation. A dose of 20 krad required 70 days to produce 100% mortality and 22 krad - 50 days. Pupae mortality ranged from 28.4 to 30.72%, depending on the dose but their moths lived only 2 days and could not be fertilized. The inference is that gamma irradiation may be used to control Ephestia Kuehniella

  13. Activation of wine bentonite with gamma rays

    International Nuclear Information System (INIS)

    The action of gamma rays on wine bentonite as well as influence of its adsorption and technologic qualities on the composition and stability of wines against protein darkening and precipitation has been studied. The experiments were carried out with wine bentonite produced in the firm Bentonite and irradiated with doses of 0.4, 0.6, 0.8 and 1.0 MR. White and red wines have been treated with irradiated bentonite under laboratory conditions at 1.0 g/dm3. All samples are treated at the same conditions. The flocculation rate of the sediment was determined visually. Samples have been taken 24 h later from the cleared wine layers. The following parameters have been determined: clarification, filtration rate, phenolic compounds, calcium, colour intensity, total extracted substances, etc. The volume of the sediment has been determined also. The control samples have been taken from the same unirradiated wines. The results showed better and faster clarification in on the third, the 20th and the 24th hours with using of gamma-irradiated at doses 0.8 and 1.0 MR. The sediment was the most compact and its volume - the smallest compared to the samples treated with bentonite irradiated with doses of 0.6 and 0.4 MR. This ensures a faster clarification and better filtration of treated wines. The bentonite activated with doses of 0.8 and 1.0 MR adsorbs the phenolic compounds and the complex protein-phenolic molecules better. In the same time it adsorbs less extracted substances compared to untreated bentonite and so preserves all organoleptic properties of wine. The irradiated bentonite adsorbs less the monomers of anthocyan compounds which ensures brighter natural colour of wine. The gamma-rays activation consolidates calcium in the crystal lattice of bentonite particles and in this way eliminates the formation of crystal precipitates

  14. The Gamma-ray Sky with Fermi

    CERN Document Server

    Thompson, D J

    2013-01-01

    Gamma rays reveal extreme, nonthermal conditions in the Universe. The Fermi Gamma-ray Space Telescope has been exploring the gamma-ray sky for more than four years, enabling a search for powerful transients like gamma-ray bursts, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as clusters of galaxies. Some results include a stringent limit on Lorentz invariance violation derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge gamma-ray structure in the direction of the center of our Galaxy, and strong constraints on some Weakly Interacting Massive Particle (WIMP) models for dark matter.

  15. Cosmic Rays: What Gamma Rays Can Say

    OpenAIRE

    Aloisio, Roberto

    2014-01-01

    We will review the main channels of gamma ray emission due to the acceleration and propagation of cosmic rays, discussing the cases of both galactic and extra-galactic cosmic rays and their connection with gamma rays observations.

  16. The Gamma-ray Universe through Fermi

    Science.gov (United States)

    Thompson, David J.

    2012-01-01

    Gamma rays, the most powerful form of light, reveal extreme conditions in the Universe. The Fermi Gamma-ray Space Telescope and its smaller cousin AGILE have been exploring the gamma-ray sky for several years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge ga.nuna-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

  17. Effects of 60Co gamma-ray local irradiation on rat liver on alkaline phosphatase, lactate dehydrogenase and catalase in the liver and serum

    International Nuclear Information System (INIS)

    Rats were given a single exposure of various doses (0, 5, 50, 500, and 5000 rads) to local irradiation of 60Co ?-ray on liver. Activities of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and catalase in the serum and liver were measured at various time intervals after irradiation. These results were summarized as follows; 1. ALP activity in the serum had no effect on irradiation up to 500 rads, but in the case of 5000 rads irradiation exhibited a marked loss from 4 days after irradiation. ALP activity in the liver to 5000 rads exposure on 7 days after irradiation increased, on the other hand in the serum decreased, and the patterns of ALP activities in the liver and serum to the irradiation doses were opposite. 2. LDH activity in the serum by exposure to 5, 500 and 5000 rads increased at 4 days after irradiation, but at 7 days significantly decreased. LDH activity in the liver to the irradiation doses on 7 days after irradiation did not markedly change, but in the serum it tended to be low in inverse proportion to the irradiation doses. 3. Catalase activity in the serum to 50 and 500 rads exposure increased at 4 days after irradiation and decreased at 7 days, but to 5000 rads exposure it decreased in the course of time. Catalase activity in the liver and serum on 7 days after irradiation were inversely proportional to irradiation doses. It is difficult that catalase activity makes a index of clinical irradiation effects, because catalase activity decrease under the various conditions, such as cancer, anemia, infection of bacterias and so on. Since activities of ALP and LDH increase in almost disease, decrease of ALP activity and decrease following temporary increase of LDH activity by irradiation may be able to become a clinical indicator on irradiation effects. (author)

  18. Gravitational microlensing of gamma-ray blazars

    DEFF Research Database (Denmark)

    F. Torres, Diego; E. Romero, Gustavo; F. Eiroa, Ernesto; Wambsganss, Joachim; Pessah, Martin Elias

    2003-01-01

    We present a detailed study of the effects of gravitational microlensing on compact and distant $\\gamma$-ray blazars. These objects have $\\gamma$-ray emitting regions which are small enough as to be affected by microlensing effects produced by stars lying in intermediate galaxies. We analyze the...... galactic latitude whose gamma-ray statistical properties are very similar to detected $\\gamma$-ray blazars) are indeed the result of gravitational lensing magnification of background undetected Active Galactic Nuclei (AGNs)....

  19. Portable compton gamma-ray detection system

    Science.gov (United States)

    Rowland, Mark S. (Alamo, CA); Oldaker, Mark E. (Pleasanton, CA)

    2008-03-04

    A Compton scattered gamma-ray detector system. The system comprises a gamma-ray spectrometer and an annular array of individual scintillators. The scintillators are positioned so that they are arrayed around the gamma-ray spectrometer. The annular array of individual scintillators includes a first scintillator. A radiation shield is positioned around the first scintillator. A multi-channel analyzer is operatively connected to the gamma-ray spectrometer and the annular array of individual scintillators.

  20. Interaction of hyperthermia with gamma rays in Allium cepa cells

    International Nuclear Information System (INIS)

    Hyperthermia treatments(40 and 50degC) applied prior to gamma ray irradiation (500 R) reduce the chromosomal damage caused by the latter significantly in Allium test. This protection has been ascribed to clastogenic adoptation and/or formation of heat shock proteins. (author). 13 refs., 2 tabs

  1. Specification of High Activity Gamma-Ray Sources.

    Science.gov (United States)

    International Commission on Radiation Units and Measurements, Washington, DC.

    The report is concerned with making recommendations for the specifications of gamma ray sources, which relate to the quantity of radioactive material and the radiation emitted. Primary consideration is given to sources in teletherapy and to a lesser extent those used in industrial radiography and in irradiation units used in industry and research.…

  2. Genetic enhancement of groundnut through gamma ray induced mutagenesis

    International Nuclear Information System (INIS)

    Induced mutagenesis along with recombination breeding played a vital role in the genetic improvement of groundnut (Arachis hypogaea L.) at Bhabha Atomic Research Centre, India. In continuation of ongoing mutation research since the 1960s, popular cv. TAG 24 was irradiated with gamma rays in order to further generate genetic variability. As expected, higher doses of gamma rays drastically affected the seedling traits in the M1 generation. In the M2, in all 71 true breeding macro mutants affecting plant height, leaf colour, leaf type, leaf size and leaf shape, flower colour, pod type, seed size and seed colour were isolated, characterized and maintained. (author)

  3. Gamma ray assisted fabrication of fluorescent oligographene nanoribbons

    International Nuclear Information System (INIS)

    Graphical abstract: Facile low cost method for production of oligographene nanoribbons is presented. Highlights: ? Gamma ray assisted fabrication of oligographene nanoribbons. ? Facile, large scale and low cost method of graphene nanoribbon fabrication. ? Produced nanoribbons are fluorescent in the blue region of visible spectrum. -- Abstract: In this paper, facile low cost method for production of oligographene nanoribbons is presented. Nanoribbons are produced by gamma ray assisted cutting of oligographene dispersed in cyclopentanone. Width and height of the smallest nanoribbons are 30 and 1 nm, respectively. Due to the presence of a small number of defects introduced by gamma irradiation, nanoribbons are photoluminescent in the UV and blue region of the visible spectrum.

  4. Gamma ray induced mutant of a mutant of chrysanthemum

    International Nuclear Information System (INIS)

    Rooted cuttings of small flowered chrysanthemum mutant Himani were irradiated with 1.5, 2.0 and 2.5 Krad of gamma rays. Reduction of survival, plant height, leaf and pollen grain size, various abnormalities in leaf and flower-heads, delay in flower bud initiation, colour showing and full bloom and increase in pollen grain sterility were recorded after exposure to gamma rays. TLC and UV spectrophotometric analysis showed quantitative differences in pigments in the control and its induced Canary Yellow mutant. (author)

  5. Organ doses of adults and children from environmental gamma rays

    International Nuclear Information System (INIS)

    Organ doses from environmental gamma-rays were calculated using Monte Carlo methods for infinite plane sources in the ground, semi-infinite volume sources in the air and volume source in the ground. The results of the simulations of the gamma-ray transport in the air over ground geometry were used as sources irradiating four different anthropomorphic phantoms representing different ages and sexes; in this way, the effect of body and organ size on organ doses could be examined. Dose conversion factors normalised to air kerma and to source intensity were obtained. (orig.)

  6. Gamma-ray signatures of classical novae

    CERN Document Server

    Hernanz, M; Jos, J

    2001-01-01

    The role of classical novae as potential gamma-ray emitters is reviewed, on the basis of theoretical models of the gamma-ray emission from different nova types. The interpretation of the up to now negative results of the gamma-ray observations of novae, as well as the prospects for detectability with future instruments (specially onboard INTEGRAL) are also discussed.

  7. Study of stability of humic acids from soil and peat irradiated by gamma rays; Estudo da estabilidade de acidos humicos extraidos de solo e turfa, frente a radiacao ionizante gama

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wilson Tadeu Lopes da

    1995-07-01

    Humic acids samples (one deriving from a sedimentary soil and other from a peat), in aqueous media, were irradiated with gamma rays, in doses of 10, 50 and 100 kGy, in order to understand their chemical behavior after the irradiation. The material, before and after irradiation, was analyzed by Elemental Analysis, Functional Groups (carboxylic acids and phenols), UV/Vis Spectroscopy (E{sub 4}/E{sub 6} ratio), IR spectroscopy, CO{sub 2} content and Gel permeation Chromatography (GPC) ). The Elemental Analysis showed the humic acid derived from a peat had a most percentage quantity of Carbon and Hydrogen than the material from a sedimentary soil. From the UV/Vis Spectroscopy, it was observed a decrease of E{sub 4}/E{sub 6} ratio with an increase of the applied dose. The data from GPC are in agreement with this. The results showed that the molecular weight of the material increased by exposing it to a larger radiolitical dose. The peat material was less affected by the gamma radiation than the soil material. The carboxylic groups were responsible by radiochemical behavior of the material. (author)

  8. Gamma Ray Spectroscopy with Scintillation Light in Liquid Xenon

    CERN Document Server

    Ni, K; Giboni, K L; Majewski, P; Yamashita, M

    2006-01-01

    Scintillation light from gamma ray irradiations in liquid xenon is detected by two Hamamatsu R9288 photomultiplier tubes (PMTs) immersed in the liquid. UV light reflector material, PTFE, is used to optimize the light collection efficiency. The detector gives a high light yield of 6 photoelectron per keV (pe/keV), which allows efficient detection of the 122 keV gamma-ray line from Co-57, with a good measured energy resolution at (8.8+/-0.6)% (sigma). The best achievable energy resolution from liquid xenon scintillation light is estimated to be around 6-8% (sigma) for gamma-ray with energy between 662 keV and 122 keV.

  9. Study of electronic transport in gamma ray exposed nanowires

    International Nuclear Information System (INIS)

    Graphical abstract: A sharp decline in the IV characteristics of Cu (and Cd) nanowires was experimentally observed after the gamma ray exposure of nanowires. Irradiation induced transformations in the granular properties and the resonance state of electronphonon coupling beyond a particular value of external field may be accountable for observed shape of IV characteristics in gamma ray exposed nanowires. - Highlights: Cu and Cd nanowires were synthesized by technique of electrodeposition in templates. The nanowires were exposed to different doses of gamma ray photons. A sharp decline in the current in IV characteristics (IVC) was observed. Structural deviation in terms of granular orientations was also analysed. The electronphonon coupling may be responsible for observed sharp decline in IVC. - Abstract: One dimensional nanostructures provide the most restricted and narrow channel for the transport of charge carriers and therefore 1D structures preserve their significance from the viewpoint of electronic devices. The net radiation effect on nanomaterials is expected to be more (due to their increased reactivity and lesser bulk volume) than their bulk counterparts. Radiation often modifies the structure and simultaneously the other physical properties of materials. In this manner, the irradiation phenomenon could be counted as a strong criterion to induce changes in the structural and electrical properties of nanowires. We have studied the effect of gamma rays on the electronic flow through Cu and Cd nanowires by plotting their IV characteristics (IVC). The IVC of gamma ray exposed nanowires was found to be a combination of the linear and nonlinear regions and a decreasing pattern in the electrical conductivity (calculated from the linear portion of IVC) was observed as we increased the dose of gamma rays

  10. A gamma ray burst model

    International Nuclear Information System (INIS)

    We present a model for gamma ray bursts based on the compression of neutron stars in close binary systems. Our general relativistic hydrodynamiccomputer simulations of close neutron star binaries have found that as the orbit shrinks the density of the neutron stars rises. This compressional effect has been estimated to produce thermal energies in the neutron stars of the order of magnitude 1052to 1053 ergs on a timescale of a few seconds.This is a possible source of energy for gamma-ray bursts. The hot neutron stars will emit neutrino pairs which will partially recombine to form an electron positron pair plasma. The pair plasma will recombine after expansion to produce photons which closely mimic the characteristics of gamma-raybursts

  11. Airborne gamma ray spectrometer surveying

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency (IAEA) in its role as collector and disseminator of information on nuclear techniques has long had an interest in gamma ray spectrometer methods and has published a number of Technical Reports on various aspects of the subject. At an Advisory Group Meeting held in Vienna in November 1986 to review appropriate activities the IAEA could take following the Chernobyl accident, it was recommended that preparation begin on a new Technical Report on airborne gamma ray spectrometer surveying, taking into account the use of the technique for environmental monitoring as well as for nuclear emergency response requirements. Shortly thereafter the IAEA became the lead organization in the Radioelement Geochemical Mapping section of the International Geological Correlation Programme/United Nations Educational, Scientific and Cultural Organization (UNESCO) Project on International Geochemical Mapping. These two factors led to the preparation of the present Technical Report. 18 figs, 4 tabs

  12. Compton suppression gamma ray spectrometry

    International Nuclear Information System (INIS)

    In the past decade there have been many studies to use Compton suppression methods in routine neutron activation analysis as well as in the traditional role of low level gamma ray counting of environmental samples. On a separate path there have been many new PC based software packages that have been developed to enhance photopeak fitting. Although the newer PC based algorithms have had significant improvements, they still suffer from being effectively used in weak gamma ray lines in natural samples or in neutron activated samples that have very high Compton backgrounds. We have completed a series of experiments to show the usefulness of Compton suppression. As well we have shown the pitfalls when using Compton suppression methods for high counting deadtimes as in the case of neutron activated samples. We have also investigated if counting statistics are the same both suppressed and normal modes. Results are presented in four separate experiments. (author)

  13. Cosmic Gamma-ray Background Radiation

    OpenAIRE

    Inoue, Yoshiyuki

    2014-01-01

    The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, or...

  14. Laser Compton back-scattering gamma-ray beamline on NewSUBARU

    International Nuclear Information System (INIS)

    A laser-Compton scattering system is a unique and useful gamma-ray-beam source. The laser-Compton scattering gamma ray generation was tested on a synchrotron radiation facility, 'NewSUBARU' at Lasti/UH. Cw Nd:YVO laser (wavelength: 1.064?m, maximum power: 5W) was used in the experiments. Maximum energies of scattered gamma ray are 17.6 and 39.1MeV at the operating electron energy of 1 and 1.5GeV, respectively. Generated gamma-ray was measured and used in the shielding tunnel of 45cm thickness concrete wall. A scintillation detector (NaI) and Ge detector were used to measure the gamma-ray spectrum and the yield. A measured gamma-ray yield of 5x103photons/s/mA/W is in agreement with calculation. A spatial distribution of gamma-ray and its dependence on a polarization of incident laser were measured using imaging plate (IP). Preliminary experiments of gamma-ray application were performed for a nuclear transmutation in the disposal of the radioactive nuclear waste and on a gamma-ray radiography for nondestructive testing of a thick subject. New radiation shielding for the gamma-ray beamline was designed for extracting the higher flux gamma-rays for application. Radiation leakage was calculated by EGS4 and MCNPX. The calculations of neutron transport are important for observation of fast neutron generated from a target sample irradiated by gamma-ray beam

  15. On Gamma-Ray Bursts

    OpenAIRE

    Ruffini, Remo; Bernardini, Maria Grazia; Bianco, Carlo Luciano; Caito, Letizia; Chardonnet, Pascal; Cherubini, Christian; Dainotti, Maria Giovanna; Fraschetti, Federico; Geralico, Andrea; Guida, Roberto; Patricelli, Barbara; Rotondo, Michael; Hernandez, Jorge Armando Rueda; Vereshchagin, Gregory; Xue, She-Sheng(ICRANet, P.zza della Repubblica 10, I-65122 Pescara, Italy)

    2008-01-01

    (Shortened) We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization aroun...

  16. Low-dose gamma-ray irradiation induces translocation of Nrf2 into nuclear in mouse macrophage RAW264.7 cells

    International Nuclear Information System (INIS)

    The transcription factor nuclear erythroid-derived 2-related factor 2 (Nrf2) regulates expression of genes encoding antioxidant proteins involved in cellular redox homeostasis, while ?-ray irradiation is known to induce reactive oxygen species in vivo. Although activation of Nrf2 by various stresses has been studied, it has not yet been determined whether ionizing irradiation induces activation of Nrf2. Therefore, we investigated activation of Nrf2 in response to ?-irradiation in mouse macrophage RAW264.7 cells. Irradiation of cells with ?-rays induced an increase of Nrf2 expression. Even 0.1 Gy of ?-irradiation induced a translocation of Nrf2 from cytoplasm to the nucleus, indicating the activation of Nrf2 by low-dose irradiation. Expression of heme oxygenase-1, which is regulated by Nrf2, was also increased at 24 h after irradiation with more than 0.1 Gy of ?-rays. Furthermore, the activation of Nrf2 was suppressed by U0126, which is an inhibitor of the extracellular signal regulated protein kinase 1/2 (ERK1/2) pathway, suggesting involvement of ERK1/2-dependent pathway in the irradiation-induced activation of Nrf2. Our results indicate that low-dose ?-irradiation induces activation of Nrf2 through ERK1/2-dependent pathways. (author)

  17. Thermo-mechanical characteristics of UV-irradiated polyurethane elastomers extended with {alpha}, {omega}-alkane diols

    Energy Technology Data Exchange (ETDEWEB)

    Zia, Khalid Mahmood [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan)], E-mail: ziakmpkpolym@yahoo.com; Bhatti, Ijaz Ahmad [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Barikani, Mehdi [Iran Polymers and Petrochemicals Institute, P.O Box 14965/115, Tehran (Iran, Islamic Republic of); Zuber, Mohammad [Department of Industrial Chemistry, G.C. University, Faisalabad (Pakistan); Sheikh, Munir Ahmad [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan)

    2009-05-15

    A series of polyurethane elastomers were prepared by the reaction of poly {epsilon}-caprolactone and 4,4'-diphenylmethane diisocyanate. The prepolymer was extended using {alpha}, {omega}-alkane diols as chain extenders having 2-10 methylene units in their structure. The synthesized samples were irradiated for 50, 100 and 200 h in an ultra violet (UV) exposure unit. Modifications in the chemical structure before and after irradiation were characterized using Fourier Transform Infrared spectroscopy. The thermal and mechanical properties were affected by the ultra violet irradiation time and the number of methylene units in the chain extenders. The experimental results indicated that the morphological structure changed during irradiation as a consequence of hard segment and soft segment degradation.

  18. DUAL Gamma-Ray Mission

    CERN Document Server

    Boggs, S; von Ballmoos, P; Takahashi, T; Gehrels, N; Tueller, J; Baring, M; Beacom, J; Diehl, R; Greiner, J; Grove, E; Hartmann, D; Hernanz, M; Jean, P; Johnson, N; Kanbach, G; Kippen, M; Kndlseder, J; Leising, M; Madejski, G; McConnell, M; Milne, P; Motohide, K; Nakazawa, K; Oberlack, U; Phlips, B; Ryan, J; Skinner, G; Starrfield, S; Tajima, H; Wulf, E; Zoglauer, A; Zych, A

    2010-01-01

    Gamma-ray astronomy presents an extraordinary scientific potential for the study of the most powerful sources and the most violent events in the Universe. In order to take full advantage of this potential, the next generation of instrumentation for this domain will have to achieve an improvement in sensitivity over present technologies of at least an order of magnitude. The DUAL mission concept takes up this challenge in two complementary ways: a very long observation of the entire sky, combined with a large collection area for simultaneous observations of Type Ia SNe. While the Wide-Field Compton Telescope (WCT) accumulates data from the full gamma-ray sky (0.1-10 MeV) over the entire mission lifetime, the Laue-Lens Telescope (LLT) focuses on 56Co emission from SNe Ia (0.8-0.9 MeV), collecting gamma-rays from its large area crystal lens onto the WCT. Two separated spacecraft flying in formation will maintain the DUAL payloads at the lens' focal distance.

  19. CAMAC gamma ray scanning system

    International Nuclear Information System (INIS)

    A flexible gamma-ray scanning system, based on a LeCroy 3500 multichannel analyzer and CAMAC modules, is described. The system is designed for making simultaneous passive and active scans of objects of interest to nuclear safeguards. The scanner is a stepping-motor-driven carriage; the detectors, a bismuth-germanate scintillator and a high-purity germanium detector. A total of sixteen peaks in the two detector-produced spectra can be integrated simultaneously, and any scan can be viewed during data acquisition. For active scanning, the 2615-keV gamma-ray line from a 232U source and the 4439-keV gamma-ray line from 9Be(α,n)12C were selected. The system can be easily reconfigured to accommodate up to seven detectors because it is based on CAMAC modules and FORTRAN. The system is designed for field use and is easily transported. Examples of passive and active scans are presented

  20. Direct irradiation of LaMn?Si? and LaMn?Ge? compounds with thermal neutrons to produce ??La(??Ce) probe nuclei for PAC Spectroscopy: analysis of possible interferences from ??Mn and ????Ge gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Bosch-Santos, Brianna; Cabrera-Pasca, Gabriel A.; Carbonari, Artur W.; Saiki, Mitiko; Saxena, Rajendra N., E-mail: brianna@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    In this paper we describe a method to introduce radioactive ??La nuclei with a half-life of ~40 h, into samples of intermetallic compounds LaMn?X? (X=Si,Ge) to carry out Perturbed gamma-gamma angular correlation (PAC) spectroscopy measurements using ??La (??Ce) as probe nuclei. While there are several methods to introduce this probe nucleus in a variety of samples, an alternate method is described which produces ??La (??Ce) probe in LaMn?Ge? and LaMn?Si? compounds by directly irradiating for a short time with thermal neutrons in the IEA-R1 nuclear reactor at IPEN/CNEN-SP. This method could be used because La is a component of the samples. Natural La contains (99.9%) as ?La isotope which, when irradiated with neutrons produces ??La, the parent radioisotope of ??Ce used for PAC measurements. However, other elements present in the compounds are also activated during neutron irradiation to produce gamma emitting radioisotopes in particular ??Mn and ????Ge. In order to verify if these would interfere in the PAC measurements, we have measured the gamma spectrum of these isotopes in the samples at different time intervals after the end of irradiation using a high resolution HPGe spectrometer PAC spectra at room temperature were measured for both LaMn?Si? and LaMn?Ge? compounds using ??La (??Ce) as probe nuclei and showed that interference from other gamma-rays is negligible if PAC measurements started 24 hs after the end of irradiation of the sample. (author)

  1. High dose gamma-ray standard

    International Nuclear Information System (INIS)

    The high gamma-ray doses produced in a gamma irradiator are used, mainly, for radiation processing, i.e. sterilization of medical products, processing of food, modifications of polymers, irradiation of electronic devices, a.s.o. The used absorbed doses are depending on the application and are covering the range between 10 Gy and 100 MGy. The regulations in our country require that the response of the dosimetry systems, used for the irradiation of food and medical products, be calibrated and traceable to the national standards. In order to be sure that the products receive the desired absorbed dose, appropriate dosimetric measurements must be performed, including the calibration of the dosemeters and their traceability to the national standards. The high dose gamma-ray measurements are predominantly based on the use of reference radiochemical dosemeters. Among them the ferrous sulfate can be used as reference dosemeter for low doses (up to 400 Gy) but due to its characteristics it deserves to be considered a standard dosemeter and to be used for transferring the conventional absorbed dose to other chemical dosemeters used for absorbed doses up to 100 MGy. The study of the ferrous sulfate dosemeter consisted in preparing many batches of solution by different operators in quality assurance conditions and in determining for all batches the linearity, the relative intrinsic error, the repeatability and the reproducibility. The principal results are the following: the linear regression coefficient - 0.999, the relative intrinsic error - max.6%, the repeatability (for P*=95%) - max.3%, the reproducibility (P*=95%) - max.5%

  2. Co-expression of antioxidant enzymes with expression of p53, DNA repair, and heat shock protein genes in the gamma ray-irradiated hermaphroditic fish Kryptolebias marmoratus larvae

    International Nuclear Information System (INIS)

    Highlights: Novel identification of DNA repair-related genes in fish. Investigation of whole expression profiling of DNA repair genes upon gamma radiation. Analysis of effects of gamma radiation on antioxidant system and cell stress proteins. Usefulness of verification of pathway-based profiling for mechanistic understanding. -- Abstract: To investigate effects of gamma ray irradiation in the hermaphroditic fish, Kryptolebias marmoratus larvae, we checked expression of p53, DNA repair, and heat shock protein genes with several antioxidant enzyme activities by quantitative real-time RT-PCR and biochemical methods in response to different doses of gamma radiation. As a result, the level of gamma radiation-induced DNA damage was initiated after 4 Gy of radiation, and biochemical and molecular damage became substantial from 8 Gy. In particular, several DNA repair mechanism-related genes were significantly modulated in the 6 Gy gamma radiation-exposed fish larvae, suggesting that upregulation of such DNA repair genes was closely associated with cell survival after gamma irradiation. The mRNA expression of p53 and most hsps was also significantly upregulated at high doses of gamma radiation related to cellular damage. This finding indicates that gamma radiation can induce oxidative stress with associated antioxidant enzyme activities, and linked to modulation of the expression of DNA repair-related genes as one of the defense mechanisms against radiation damage. This study provides a better understanding of the molecular mode of action of defense mechanisms upon gamma radiation in fish larvae

  3. Co-expression of antioxidant enzymes with expression of p53, DNA repair, and heat shock protein genes in the gamma ray-irradiated hermaphroditic fish Kryptolebias marmoratus larvae

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, Jae-Sung [Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Bo-Mi; Kim, Ryeo-Ok [Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Seo, Jung Soo [Pathology Team, National Fisheries Research and Development Institute, Busan 619-902 (Korea, Republic of); Kim, Il-Chan [Division of Life Sciences, Korea Polar Research Institute, Korea Institute of Ocean Science and Technology, Incheon 406-840 (Korea, Republic of); Lee, Young-Mi, E-mail: ymlee70@smu.ac.kr [Department of Green Life Science, College of Convergence, Sangmyung University, Seoul 110-743 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@hanyang.ac.kr [Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2013-09-15

    Highlights: Novel identification of DNA repair-related genes in fish. Investigation of whole expression profiling of DNA repair genes upon gamma radiation. Analysis of effects of gamma radiation on antioxidant system and cell stress proteins. Usefulness of verification of pathway-based profiling for mechanistic understanding. -- Abstract: To investigate effects of gamma ray irradiation in the hermaphroditic fish, Kryptolebias marmoratus larvae, we checked expression of p53, DNA repair, and heat shock protein genes with several antioxidant enzyme activities by quantitative real-time RT-PCR and biochemical methods in response to different doses of gamma radiation. As a result, the level of gamma radiation-induced DNA damage was initiated after 4 Gy of radiation, and biochemical and molecular damage became substantial from 8 Gy. In particular, several DNA repair mechanism-related genes were significantly modulated in the 6 Gy gamma radiation-exposed fish larvae, suggesting that upregulation of such DNA repair genes was closely associated with cell survival after gamma irradiation. The mRNA expression of p53 and most hsps was also significantly upregulated at high doses of gamma radiation related to cellular damage. This finding indicates that gamma radiation can induce oxidative stress with associated antioxidant enzyme activities, and linked to modulation of the expression of DNA repair-related genes as one of the defense mechanisms against radiation damage. This study provides a better understanding of the molecular mode of action of defense mechanisms upon gamma radiation in fish larvae.

  4. Studies on the sensitivity of guinea pigs and golden hamsters irradiated with different doses of gamma rays to infections with R and S forms of Pseudomonas pseudomallei

    International Nuclear Information System (INIS)

    Whole-body gamma irradiation was carried out on guinea pigs of both sexes with 2 Gy (sublethal dose), 2 Gy fractionated (4 x 0.5 Gy a day) and 0.5 Gy, and on golden hamsters with 6 Gy (sublethal dose) and 0.5 Gy. The animals were injected i.p. 24 h after irradiation with bacterial suspensions of P. pseudomallei R7 and R15. The results showed a great increase of sensitivity to infection in the animals irradiated with sublethal dose, both as regards the R and S forms. Susceptibility rose appreciably also in guinea pigs irradiated fractionally with a dose of 2 Gy and to a relatively lower degree upon irradiation with 0.5 Gy. For the golden hamsters the sensitivity toward both investigated strains was extremely high and it remained unchanged upon irradiation with 6 Gy and 0.5 Gy. The data obtained provided grounds for the existence of a certain correlation between the different radioresistance of guinea pigs and golden hamsters and the changes established in their sensitivity to infections with R and S forms of Ps. pseudomallei after whole-body gamma irradiation

  5. Repeated 0.5 Gy gamma-ray irradiation attenuates autoimmune disease in MRL-lpr/lpr mice with up-regulation of regulatory T cells

    International Nuclear Information System (INIS)

    Complete text of publication follows. MRL-lpr/lpr mice present a single gene mutation on the Fas (CD95) gene that leads to reduced signaling for apoptosis. With aging, these mice spontaneously develop autoimmune disease and are used as a model of systemic lupus erythematosus. We previously reported attenuation of autoimmune disease in MRL-lpr/lpr mice by repeated γ-ray irradiation (0.5 Gy each time). In this study, we investigated the mechanisms of this attenuation focusing the highly activated CD3+CD4-CD8-B220+ T cells, which are characteristically involved in autoimmune pathology in these mice. We measured the weight of the spleen and the population of CD3+CD4-CD8-B220+ T cells. Splenomegaly and increase in percentage of CD3+CD4-CD8-B220+ T cells, which occur with aging in non-irradiated mice, were suppressed in irradiated mice. To investigate the function of CD3+CD4-CD8-B220+ T cells, we isolated these cells from splenocytes by magnetic cell sorting. Isolated CD3+CD4-CD8-B220+ T cells were more resistant to irradiation-induced cell death than isolated CD4+ T cells. Although high proliferation rate and IL-6 production were observed in isolated CD3+CD4-CD8-B220+ T cells, the proliferation rate and IL-6 production were lower in the cells isolated from the irradiated mice. Moreover, the production of autoantibodies (anti-collagen antibody and anti-single strand DNA antibody) was also lowered by irradiation. These results indicate that activation of CD3+CD4-CD8-B220+ T cells and progression of pathology would be suppressed by repeated 0.5 Gy γ-ray irradiation. To uncover the mechanism of the immune suppression, we analyzed population of regulatory T cells (CD4+CD25+Foxp3+), which suppress activated T cells and excessive autoimmune responses. Intriguingly, significant increase of the percentage of regulatory T cells was observed in irradiated mice. In conclusion, we found that repeated 0.5 Gy γ-ray irradiation suppresses proliferation rate of CD3+CD4-CD8-B220+ T cells and productions of IL-6 and autoantibodies, and up-regulates regulatory T cells. These results indicate that up-regulation of regulatory T cells would involve in these therapeutic effects induced by irradiation. The up-regulation of regulatory T cells induced by irradiation could be a novel and important observation in low-dose irradiation-mediated therapeutic effects.

  6. Gamma-ray irradiation effect on corrosion rates of stainless steel, Ti and Ti-5Ta in boiling 9N nitric acid

    International Nuclear Information System (INIS)

    Irradiation effect of ?-rays on corrosion rates of stainless steel (type 304L), titanium and a titanium-tantalum alloy (Ti-5Ta) in 9N boiling nitric acid was investigated by measuring weight losses of specimens leached under a 60Co ?-ray environment of 1 kC kg-1/h (4 MR/h). Tests without irradiation were as well performed to obtain reference data. Plots of the weight loss normalized to specimen's surface area against total leaching time exhibited linear relations when the first leaching batch is neglected. The corrosion rates calculated from the gradients indicated slight, though significant, irradiation effects, an enhancement in stainless steel while suppressions in Ti and Ti-5Ta. Corrosion modes were found to be insensitive to the irradiation. (orig.)

  7. Leakage of potassium from red blood cells following gamma ray irradiation in the presence of dipyridamole, trolox, human plasma or mannitol

    International Nuclear Information System (INIS)

    Transfusion-associated graft-versus-host disease (TA-GVHD) is a fatal complication of blood transfusion resulting from the contamination of blood products by leukocytes. In order to prevent this disease, gamma or X-ray irradiation of blood components, which can inactivate leukocytes, is currently used. However, the minimal doses needed to destroy lymphocytes promote the leakage of potassium from red blood cells (RBCs), which can induce other side effects, such as hyperpotassemia and cardiac arrest. The reactive oxygen species (ROS) generated by the irradiation of aqueous solutions may accelerate the leakage through oxidation of the RBC membrane. Here we studied the effect of dipyridamole, Trolox, human plasma or mannitol on the leakage of potassium from RBCs following irradiation. RBC preparations (hematocrit; 30%) containing antioxidants were irradiated at 30 Gy and stored at 4 deg C for 7 d. The leakage of potassium from the RBCs caused by the irradiation was significantly suppressed by dipyridamole (more than 50 ?M), Trolox (more than 5 mM) or human plasma (50%). Mannitol (80 mM) is used to inhibit hemolysis as a constituent of MAP solution, which is a solution used for the storage of RBC products in Japan. Here it was clarified that the leakage of potassium from not only irradiated but also non-irradiated RBCs was unexpectedly promoted by mannitol. The amount of mannitol in MAP solution may have to be reconsidered. The osmotic pressure of the RBC preparation increased in a manner dependent on the concentration of mannitol. The elevated osmotic pressure may promote the leakage. In conclusion, although antioxidants have the potential to suppress the leakage of potassium ascribed to the irradiation, the extent of the supression (10-20%) by dipyridamole (DPM), Trolox or human plasma seems insufficient for the clinical use of these agents as an additive for MAP solution. (author)

  8. Fillers influence on mechanical properties of elastomers during their ageing by irradiation; Influence des charges sur les proprietes mecaniques des elastomeres lors de leur vieillissement par irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Planes, E.; Chazeau, L.; Vigier, G. [Institut National des Sciences Appliquees (INSA), MATEIS, UMR CNRS 5510, 69 - Villeurbanne (France); Planes, E. [NEXANS Research Center, 69 - Lyon (France); Stevenson, I. [Laboratoire des Materiaux Polymeres et Biomateriaux (IMP/LMPB) UMR CNRS 5627, UCBL, 69 - Villeurbanne (France)

    2008-07-01

    This paper presents the study of ageing under irradiation of filled elastomers, particularly aluminium tri-hydrate ATH or nano-scopic silica filled EPDM. The materials have been physico-chemically, micro-structurally and mechanically characterised at various levels of ageing: here only results for physical and mechanical properties (at small (DMA) and large deformations) have been presented. From these analyses, the competition between crosslinking and chains scissions during irradiation was highlighted. Moreover, a strong influence of fillers on mechanical properties during ageing was observed. (authors)

  9. Gamma ray irradiated goat milk: comparative sensorial analysis with pasteurized goat milk; Leite de cabra irradiado com raios gama: analise sensorial comparativa com o leite de cabra pasteurizado

    Energy Technology Data Exchange (ETDEWEB)

    Gurgel, Maria Sylvia de C.C. do Amaral; Domarco, Rachel E.; Spoto, Marta H.F. [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Irradiacao de Alimentos

    2002-07-01

    Goat milk consumption has increased in the last years, due to its better digestibility and for constituting a good alternative to cow milk for intolerant people. Brazil has over 10 millions goats, mainly in the Northeast area. Considering that it is very important to increase the shelf-life for this product, this work was done to test the gamma-radiation as a preservation method, evaluating acceptability by sensorial analysis compared with pasteurized milk. The goat milk was bought in the Animal Production Department/ESALQ/USP, Piracicaba, and irradiated with 3,5 kGy in the Food Irradiation Laboratory/CENA/USP, using a cobalt-60 irradiator, type Gammabeam-650, from Nordion, Canada. After irradiation, the samples were maintained under refrigeration at 5 deg C and submitted to sensorial analysis at 1{sup st}, 7{sup th} and 15{sup th} days by 30 untrained tasters. The results indicated, by Tukey test, a significant preference for the pasteurized milk in comparison to the irradiated one, because a hard caprine flavor was developed by the irradiation. (author)

  10. Development of nonhalogen elastomers that withstand high radiation and are flame retarding

    International Nuclear Information System (INIS)

    For the electric wires and cables used for nuclear power stations, various polymer materials with excellent radiation resistance are used. Further in spent fuel reprocessing facilities and radioactive waste treatment facilities constructed recently, the materials having higher grade radiation resistance have become necessary. Furthermore, for ensuring safety at the time of fires, it has been examined to make covering materials incombustible and nonhalogen. In this study, attention was paied to cable sheath materials, and the selection of polymers and the examination on the kinds and amount of radiation resistant additives were carried out, as the result, the flame retarding, nonhalogen elastomer that has flexibility after the irradiation with gamma ray of 10 MGy, and maintains the elongation of more than 200% has been developed, therefore, it is reported in this paper. The samples, gamma ray irradiation, the test items and the test results of sheath materials, the effect of adding antiaging agent, the change of the antiaging agent due to gamma ray irradiation and so on are reported. AEM has the most excellent radiation resistance. (K.I.)

  11. Radiation cross-linking of elastomers in the presence of chlorine-containing and chroman compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mamedov, S.M.; Zakharova, E.I.; Sarycheva, I.K. [and others

    1992-03-01

    The role of hexachloro-p-xylene (HCPX) and 6-hydroxy-2,2,5, 7,8-pentamethylchroman (HPMC) in butadiene-nitrile rubbers (SKN) in the systems SKN-40+HCPX+ZnO and SKN- 40+HPMC+ZnO exposed to radiation was investigated. A change in the molecular structure of the SKN-40 rubber in the presence of HCPX and HPMC after irradiation with a dose of 150 kGy of {gamma}rays was demonstrated by physicochemical and spectral methods. The cross-linking yields and appearance of cross-links in the elastomers were determined for each system studied as a function of the absorbed dose. A hypothesis was advanced concerning the mechanism of radiation-heterogeneous conversion of elastomers in the presence of HCPX. 17 refs., 3 figs., 1 tab.

  12. Induction and repair of strand breaks and 3'-hydroxy terminals in the DNA of mammalian cells in culture following gamma-ray irradiation

    International Nuclear Information System (INIS)

    DNA was isolated in a fairly pure and intact state from cultured mouse leukaemia cells (L5178Y) after ?-ray irradiation using a hydroxyapatite column chromatography method, and analysed further by sucrose gradient centrifugation or DNA polymerase (EC 2.7.7.7, enzyme A of Klenow from Escherichia coli) assay. Irradiation of the cells induced single- and double-strand breaks in the DNA with an efficiency of 100 eV/break and 1300 eV/break, respectively. Approximately 50% of the single-strand breaks were estimated to be those arising from alkali-labile lesions. A linear, dose-dependent increase was found in the template activity of the DNA, indicating the induction of 3'-OH terminals by ?-irradiation. Post-irradiation incubation of the cells in serum-free medium allowed the majority of the breaks to rejoin within a few hours. Repair of the alkali-labile lesions was, however, found to be much slower than that of 'actual' single-strand breaks. A slight increase of the DNA template activity was found during the period of post-irradiation incubation. The reason for the increase is discussed

  13. Effect of multiple irradiation with low doses of gamma-rays on morphological transformation and growth ability of human embryo cells in vitro

    International Nuclear Information System (INIS)

    The authors measured expression of transformed phenotypes in human embryo (HE) cells repeatedly irradiated with a dose of 7.5 cGy per week throughout the life span of these cells in vitro. Irradiation was repeated until the cells had accumulated 195 cGy when the cells had reached the equivalent of their 26th passage and samples of cells at several passages were assayed for cell survival by colony formation, for mutation at hypoxanthin guanine phosphoribosyl transferase (HGPRT) locus and for transformation by focus formation. The lifespan (mean population doublings) of multiple irradiated cultures with a total dose of 97.5 cGy was slightly, but significantly, prolonged over that of controls. Although transformed foci were not observed with cells until cells had accumulated 97.5 cGy, it increased with increasing accumulated dose. No cells, however, showed unlimited life span in vitro and also expressed tumorigenicity. (author)

  14. Saturation of polymer yield during postpolymerization of gamma-ray irradiated 2-amino-4-N-methylanilino-6-isopropenyl-1,3,5-triazine

    International Nuclear Information System (INIS)

    The postpolymerization of 2-amino-4-N-methylanilino-6-isopropenyl-1,3,5-triazine (AMIT) irradiated in glassy-state with ?-ray of 60Co at -780C was investigated. The DSC of AMIT irradiated in glassy-state showed a glass-transition temperature at 160C and an exothermic peak due to polymerization at temperature near 410C. This fact shows that the active species are trapped in the glass without causing polymerization until the glass-transition temperature is reached. The post-polymerization at 30 -- 1100C of samples irradiated at -780C gave polymers in saturated yields which depend on the polymerization temperature. It is shown by the measurement of ESR spectra and Gordon-Taylor's plot that a cause of the saturation of the polymer yield is not the disappearance of the active species but the glass formation of the polymer and monomer mixture during the postpolymerization. (auth.)

  15. Prompt Gamma Ray Measurement Facilities at Japan Research Reactor-3 (JRR-3)

    International Nuclear Information System (INIS)

    This paper briefly describes the present status of the two prompt gamma ray measurement facilities, PGA and MPGA, installed on neutron beam lines attached to Japan Research Reactor-3 (JRR-3). The description includes those on the configuration of the beam line as well as the supporting system of the irradiation sample, neutron intensity at the irradiation position, and detectors used for the prompt gamma ray measurement, for each of the facilities. (author)

  16. Comparison study of DNA synthesis, single strand breaks and repair in T and B lymphocytes after 60Co gamma-rays irradiation

    International Nuclear Information System (INIS)

    The synthesis of DNA in T, B lymphocytes was investigated by the determination of 3H-TdR incorporation after Gamma-irradiation. The DNA ssb (single strand breaks) and repair in lymphocytes were measured by alkaline elution. The DNA synthesis in B lymphocytes was much lower than that in T lymphocytes. No significant difference in DNA ssb was found between T and B lymphocytes. But a less effecient process of repair was observed in B lymphocytes, So it was conceived that B lymphocytes were more sensitive to Gamma-irradiation than T lymphocytes and DNA synthesis might be related with the repair of DNA ssb

  17. Body weight and enzymes activities in blood plasma of chickens hatched from eggs irradiated with low level gamma rays before incubation

    Directory of Open Access Journals (Sweden)

    Kraljević Petar

    2009-01-01

    Full Text Available An attempt was made to determine the effect of eggs irradiation by low dose gamma radiation upon body weight (BW, body weight gain (BWG, feed consumption (FC and feed conversion ratio (FCR of chickens hatched from irradiated eggs. Our aim was also to investigate the activity of aspartate aminotransferase (AST, alanine aminotransferase (ALT, acid phosphatase (ACP and alkaline phosphatase (ALP in the blood plasma of those chickens. The eggs of heavy breed chickens were irradiated with a dose of 0.15 Gy gamma radiation (60Co before incubation. Along with the chickens which were hatched from irradiated eggs, there was a control group of chickens hatched from nonirradiated eggs. All other conditions were the same for both groups of chickens. BW of chickens was measured by a single weighting of chickens on the 1st and 42nd day of the fattening period. An average BWG was calculated from the obtained results during the whole fattening period (i.e. from the 1st until the 42nd day. FC was measured each day during the fattening time and total feed consumption was calculated. On the basis of FC and BW, FCR was calculated (FC/BWG. Blood samples were taken from the right jugular vein on the 1st and 3rd day, or from the wing vein on days 5, 7, 10, 20, 30 and 42. The activity of all enzymes was determined spectrophotometrically by using reagents according to recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine. BW of chickens hatched from irradiated eggs was statistically significant higher than in the controls during the fattening period; on day 42 of fattening, BW of the experimental chickens was 90 g (i.e. 4.8 % higher than in the controls (P<0.05. FC during the fattening period did not essentially differ in the experimental and the control group. The AST activity was significantly increased in blood plasma of chickens hatched from irradiated eggs on days 3 and 10 (P<0.05, ALT activity was increased in the same chickens only on the 10th day (P<0.05. The activity of ACP in the blood plasma of the same chickens was increased on day 42 (P<0.001 and the activity of ALP in the blood plasma of chickens hatched from irradiated eggs was decreased on day 42 (P<0.001. The obtained results indicate that low doses of gamma radiation have a stimulative effect upon metabolic processes in chickens hatched from eggs irradiated before incubation, which is proved by increase of BWG and BW, as well as by increase of AST, ALT and ACP activities in blood plasma.

  18. Effect of serial irradiation of low dose gamma rays on the growth and photosynthesis of red pepper (capsicum annuum L.) plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hong; Wi, Seung Gon; Chung, Byung Yeoup; Baek, Myung Hwa; Yang, Dae Hwa; Kim, Jae Sung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2004-07-01

    Ionizing radiation at several grays can induce growth stimulation in plants. This phenomenon has been called 'radiation hormesis'. Low dose radiation also modulates photosynthesis. Although an alteration in photosynthesis has been thought to involve in the growth stimulation of irradiated plants, no reports did clarify their relationship yet. In the present study, we attempted to reveal a possible relationship between them by comparing the effects of serial gamma-irradiation on the growth and photosynthesis of red pepper. Furthermore, something beyond the dose effect of ionizing radiation is discussed by this new experimental approach.

  19. Effect of serial irradiation of low dose gamma rays on the growth and photosynthesis of red pepper (capsicum annuum L.) plants

    International Nuclear Information System (INIS)

    Ionizing radiation at several grays can induce growth stimulation in plants. This phenomenon has been called 'radiation hormesis'. Low dose radiation also modulates photosynthesis. Although an alteration in photosynthesis has been thought to involve in the growth stimulation of irradiated plants, no reports did clarify their relationship yet. In the present study, we attempted to reveal a possible relationship between them by comparing the effects of serial gamma-irradiation on the growth and photosynthesis of red pepper. Furthermore, something beyond the dose effect of ionizing radiation is discussed by this new experimental approach

  20. Flares in Gamma Ray Bursts

    OpenAIRE

    Chincarini, G.; Mao, J.; Pasotti, F.; Margutti, R.; Guidorzi, G.; Bernardini, M. G.; team, Swift Italian

    2008-01-01

    The flare activity that is observed in GRBs soon after the prompt emission with the XRT (0.3-10 KeV) instrument on board of the Swift satellite is leading to important clues in relation to the physical characteristics of the mechanism generating the emission of energy in Gamma Ray Bursts. We will briefly refer to the results obtained with the recent analysis and and discuss the preliminary results we obtained with a new larger sample of GRBs [limited to early flares] based o...