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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

    Banerjee, S.(Tata Institute of Fundamental Research-HECR, Mumbai, India); Sinha, N K; Gayathri, N.; Ponraju, D; Dash, S.; Tyagi, A. K.; 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 b...

  2. Effects of gamma ray and electron beam irradiation on the mechanical, thermal, structural and physicochemical properties of poly (ether-block-amide) thermoplastic elastomers.

    Murray, Kieran A; Kennedy, James E; McEvoy, Brian; Vrain, Olivier; Ryan, Damien; Cowman, Richard; Higginbotham, Clement L

    2013-01-01

    Both gamma ray and electron beam irradiation are widely used as a means of medical device sterilisation. However, it is known that the radiation produced by both processes can lead to undesirable changes within biomedical polymers. The main objective of this research was to conduct a comparative study on the two key radiosterilisation methods (gamma ray and electron beam) in order to identify the more detrimental process in terms of the mechanical, structural, chemical and thermal properties of a common biomedical grade polymer. Poly (ether-block-amide) (PEBA) was prepared by injection moulding ASTM testing specimens and these were exposed to an extensive range of irradiation doses (5-200 kGy) in an air atmosphere. The effect of varying the irradiation dose concentration on the resultant PEBA properties was apparent. For instance, the tensile strength, percentage elongation at break and shore D hardness can be increased/decreased by controlling the aforementioned criteria. In addition, it was observed that the stiffness of the material increased with incremental irradiation doses as anticipated. Melt flow index demonstrated a dramatic increase in the melting strength of the material indicating a sharp increase in molecular weight. Conversely, modulated differential scanning calorimetry established that there were no significant alterations to the thermal transitions. Noteworthy trends were observed for the dynamic frequency sweeps of the material, where the crosslink density increased according to an increase in electron beam irradiation dose. Trans-vinylene unsaturations and the carbonyl group concentration increased with an increment in irradiation dose for both processes when observed by FTIR. The relationship between the irradiation dose rate, mechanical properties and the subsequent surface properties of PEBA material is further elucidated throughout this paper. This study revealed that the gamma irradiation process produced more adverse effects in the PEBA

  3. Gamma-ray spectroscopy on irradiated fuel rods

    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 irradiation for sludge solubilization and biological nitrogen removal

    This study was conducted to investigate the effects of gamma ray irradiation on the solubilization of waste sewage sludge. The recovery of an organic carbon source from sewage sludge by gamma ray irradiation was also studied. The gamma ray irradiation showed effective sludge solubilization efficiencies. Both soluble chemical oxygen demand (SCOD) and biochemical oxygen demand (BOD5) increased by gamma ray irradiation. The feasibility of the solubilized sludge carbon source for a biological nitrogen removal was also investigated. A modified continuous bioreactor (MLE process) for a denitrification was operated for 20 days by using synthetic wastewater. It can be concluded that the gamma ray irradiation was useful for the solubilization of sludge and the recovery of carbon source from the waste sewage sludge for biological nitrogen removal. - Research highlights: → This study was conducted to investigate the effects of gamma ray irradiation on the solubilization of waste sewagesludge. → The recovery of an organic carbon source from sewage sludge by gamma ray irradiation was also studied. → It can be concluded that the gamma ray irradiation was useful for the solubilization of sludge and the recovery of carbon source from the waste sewage sludge for biological nitrogen removal.

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

    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. Inactivation of citrus tristeza virus by gamma ray irradiation

    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.)

  7. Gamma-ray irradiation tests of High-Tc SQUID

    Gamma-ray irradiation tests of High-Tc SQUIDs were carried out to examine their workability in nuclear reactor environments. The SQUIDs were made of a HoBa2Cu3O7-x superconductive thin film on SrTiO3 substrates. Some were encapsulated in separate cases of glass-fiber-rein-forced epoxy resin. Gamma-ray irradiation was performed with a Co-60 gamma-ray source. Irradiation dose rates were (8.1 to 12.2) x 103 Gy/h (i.e., (1.0 to 1.5) x 106 R/h), and the maximum absorption dose was about 10.4 MGy. During and after irradiation, noises of SQUIDs were measured with a power spectrum analyzer. Changes in modulation voltage were also investigated. No gamma-ray induced noise was observed during irradiation. The noise level and modulation voltage did not change until a total irradiation dose of about 3 MGy, and after that it decreased slightly. We concluded that the tested high-Tc SQUIDs are very resistant to gamma-ray irradiation, and thus the application of high-Tc SQUIDs in inspection of reactor components seems promising. (author)

  8. Thermal decomposition of ammonium perchlorate during gamma-ray irradiation

    To assess radiation damage effects in propellants, pyrotechnics, and similar materials, thermal decomposition measurements were made on ammonium perchlorate powders and crystals during gamma-ray irradiation. Gas evolution studies were made on single crystals and powders of ammonium perchlorate, both at room temperature and at 2270C. The results are discussed. (U.S.)

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

    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

  10. Degradation of dibutyl phthalate in water by the aid of metals under {gamma}-ray irradiation

    Yoshida, Tomoko; Tanabe, Tetsuo [Nagoya Univ., Center for Integrated Research in Science and Engineering, Nagoya, Aichi (Japan); Miyashita, Yoshinori; Yoshida, Hisao; Hattori, Tadashi [Nagoya Univ., Department of Applied Chemistry, Nagoya, Aichi (Japan)

    2001-09-01

    The degradation of dibutyl phthalate (DBP), one of endocrine disrupters, by {gamma}-ray irradiation was enhanced by the effective energy conversion of {gamma}-ray through the interaction with some kind of metal materials. (author)

  11. Apoptosis and necrosis in testes irradiated with gamma rays

    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)

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

    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.

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

    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)

  14. A commercial gamma-ray irradiation plant in Japan

    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)

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

    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.

  16. Gamma Rays Irradiation Effects on Polysulfones at Elevated Temperature

    Polysulfone has excellent mechanical and thermal properties. Its application covers a wide rage such as nuclear facilities and space environment. The radiation chemical scheme on polysulfone is not well established as it undergoes both scission and cross-linking. In this study, the temperature dependence of the irradiation effect on polysulfone was studied by measuring glass transition temperature, gel fraction, molecular weight and gas evolution. Polysulfone film of 50 micrometer thickness was irradiated with gamma rays at dose rate of 5-7 kGy/h to absorbed dose of 0.1-4 MGy under vacuum in glass ampoules at room temperature, 100, 150, 180, 210 degree. Glass transition temperature (Tg) measured with differential scanning calorimeter lowered with dose upon irradiation at room temperature and 100 centigrade, though Tg rose upon irradiation above 180 centigrade, respectively. Gel fraction in chloroform at room temperature was measured. Pristine polysulfone is soluble to chloroform but after irradiation it formed gel. The decrease of gel dose, and the increase of gel fraction were observed with elevation of irradiation temperature. The number average molecular weight measured with gel permeation chromatography decreased with dose at irradiation temperatures except for 210 degree, where slight increase was observed. On the other hand, weight average molecular weight increased at all temperatures. The molecular weight distribution changed towards lower direction and became broad at all cases examined. These results indicate that the predominant scheme is scission but simultaneous cross-linking occurs, especially at elevated temperature. The probability of the cross-linking was increased by irradiation at elevated temperature above 180 degree, though the probability of main chain scission was not changed very much. The yield of evolution of total gas, CO, CO2 and SO2 gases increased at elevated temperature, while yield of evolved H2 was independent of irradiation

  17. Water radiolysis in a crack tip under gamma ray irradiation

    Under a non-irradiation condition, oxidant, e.g., O2 and H2O2, in a crack tip is supplied from the bulk water. But under irradiation conditions, even if the diffusion of radiolytic species is not sufficient, direct radiolysis in the crack tip causes high concentrations of radiolytic species. As a result of measurements and Monte Carlo calculation of gamma ray energy deposition, it has been confirmed that the energy deposition rate in the gap water is larger than that in the bulk water. The energy absorption rate increases as the gap width decreases and reaches 1.3 times that in the bulk water. In order to evaluate crack propagation rate for irradiation assisted stress corrosion cracking (IASCC) of stainless steel, a water radiolysis model in a crevice is proposed. A larger energy deposition rate in the crevice water produces many more radiolytic species, which causes high oxidant concentrations in spite of enhanced recombination of the species at the crevice inner surface. So, for IASCC evaluation, crevice water chemistry plays an important role to determine the crack propagation rate under irradiation. (authors)

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

    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

  19. Chromatographic study of gamma-ray irradiated degradation of chlorinated hydrocarbon in water

    Degradation of chlorinated hydrocarbon in gamma ray irradiation was examined in order to get information on treatment of groundwater. Water chloroform was sealed into a vial irradiated with gamma ray. Both gas chromatography and ion chromatography were applied for determination of degradation products. Carbon dioxide, carbon monoxide, methane, ethane and chloride ion were detected in the irradiated system. Effect of radiation dose on the gamma ray induced chloroform degradation was investigated. The elimination of chloride ion and the degradation of chloroform were promoted by gamma irradiation in a dose-dependent manner. The G(CHCl3), which was defined as the number of degraded chloroform molecules when absorbed 100eV, was inferred to be 3.1. The degradation mechanism of chloroform irradiated with gamma ray seemed to involve that chloroform reacted with electron from radiolysis of water and the elimination of chloride ion occurred. (author)

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

    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.

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

    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...

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

    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(γ,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

  3. Electrical conduction and photoresponses of gamma-ray-irradiated single-stranded DNA/single-walled carbon nanotube composite systems

    Hong, W.; Lee, E.M.; Kim, D.W.; Lee, Cheol Eui, E-mail: rscel@korea.ac.kr

    2015-04-15

    Highlights: •Effects of gamma-ray irradiation on single-stranded DNA (ssDNA)/single-walled carbon nanotube (SWNT) composite films. •Barrier for thermally activated conduction in the composite systems modified by the gamma-ray irradiation. •Photoresponses reveal photoexcitation and oxygen photodesorption modified by gamma-ray irradiation. -- Abstract: Effects of gamma-ray irradiation on the electrical conductivity and photoresponse have been studied for single-stranded DNA (ssDNA)/single-walled carbon nanotube (SWNT) composite films. The temperature-dependent electrical conductivity of the ssDNA/SWNT composite films, well described by a fluctuation-induced tunneling model, indicated modification of the barrier for thermally activated conduction by the gamma-ray irradiation. Besides, the photoresponse measurements indicated modified photoexcited charge carrier generation and oxygen photodesorption in the composite systems due to the gamma-ray irradiation.

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

    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 Young’s 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 Young’s modulus of the fibers increased with increasing irradiation dose

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

    Li, Bin [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Feng, Yi, E-mail: fyhfut@163.com [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Qian, Gang; Zhang, Jingcheng [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zhuang, Zhong; Wang, Xianping [Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2013-11-15

    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 Young’s 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 Young’s modulus of the fibers increased with increasing irradiation dose.

  6. Suppressing effect of low-dose gamma-ray irradiation on collagen-induced arthritis

    We previously reported attenuation of autoimmune disease by low-dose gamma-ray irradiation in MRL-lpr/lpr mice. Here, we studied the effect of low-dose gamma-ray irradiation on collagen-induced arthritis (CIA) in DBA/1J mice. Mice were immunized with type II collagen, and exposed to low-dose gamma-rays (0.5 Gy per week for 5 weeks). Paw swelling, redness, and bone degradation were suppressed by irradiation, which also delayed the onset of pathological change and reduced the severity of the arthritis. Production of tumor necrosis factor-alpha, interferon-gamma, and interleukin-6, which play important roles in the onset of CIA, was suppressed by the irradiation. The level of anti-type II collagen antibody, which is essential for the onset of CIA, was also lower in irradiated CIA mice. The population of plasma cells was increased in CIA mice, but irradiation blocked this increase. Since regulatory T cells are known to be involved in suppression of autoimmune disease, the population of CD4+CD25+Foxp3+ regulatory T cells was measured. Intriguingly, a significant increase of these regulatory T cells was found in irradiated CIA mice. Overall, our data suggest that low-dose gamma-ray irradiation could attenuate CIA through suppression of pro-inflammatory cytokines and autoantibody production, and induction of regulatory T cells. (author)

  7. Effect of gamma ray irradiation on seed germination of Ardisia crenata

    The seeds of Ardisia crenata were used as experimental material and treated with gamma ray under the irradiative doses ranging from 50∼500 Gy. The results showed that the seed germination rates were not affected under the irradiative dose of 150 Gy and below. The germination potentiality turned to reduce while the irradiative dose was higher than 250 Gy. And in the range of 300∼500 Gy the germination rates were decreased with the increase of the irradiative dose. (authors)

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

    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)

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

    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)

  10. Performance analysis of gamma-ray-irradiated color complementary metal oxide semiconductor digital image sensors

    The performance parameters of dark output images captured from color complementary metal oxide semiconductor (CMOS) digital image sensors before and after gamma-ray irradiation were studied. The changes of red, green and blue color parameters of dark output images with different gamma-ray doses and exposure times were analyzed with our computer software. The effect of irradiation on the response of blue color was significantly affected at a lower dose. The dark current density of the sensors increases by three orders at > 60 krad compared to that of unirradiated sensors. The maximum and minimum analog output voltages all increase with irradiation doses, and are almost the same at > 120 krad. The signal to noise ratio is 48 dB before irradiation and 35 dB after irradiation of 180 krad. The antiradiation threshold for these sensors is about 100 krad. The primary explanation for the changes and the degradation of device performance parameters is presented. (author)

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

    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)

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

    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)

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

    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

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

    Freeze-dried IgG with incomplete anti-Rh0(D) activity retained its reactivity after irradiation with a dose of 1.5 - 2.5 Mrad γ-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)

  15. Germination Viability of Maize M1 Seeds (Zea mays L.) after Gamma Ray Irradiation

    Rafiuddin; Dahlan, Dahliana; Musa, Yunus; Rasyid, Burhanuddin; BDR, Muh. Farid

    2013-01-01

    A series of researches was carried out to obtain mutant of maize induced by gamma rays irradiation. This initial report was from a study confirming the best dosage of irradiation at 50% lethal dosage (LD50) conducted at the Laboratory of Seed Science and Technology, Faculty of Agriculture, Hasanuddin University, Makassar from March to June 2012. The research was set up using split plot design of the Randomized Complete Block design. Data were analyzed using analysis of variance...

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

    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

  17. Gamma ray irradiated silicon nanowires: An effective model to investigate defects at the interface of Si/SiOx

    The effect of gamma ray irradiation on silicon nanowires was investigated. Here, an additional defect emerged in the gamma-ray-irradiated silicon nanowires and was confirmed with electron spin resonance spectra. 29Si nuclear magnetic resonance spectroscopy showed that irradiation doses had influence on the Q4 unit structure. This phenomenon indicated that the unique core/shell structure of silicon nanowires might contribute to induce metastable defects under gamma ray irradiation, which served as a satisfactory model to investigate defects at the interface of Si/SiOx

  18. Gamma ray irradiated silicon nanowires: An effective model to investigate defects at the interface of Si/SiOx

    Yin, Kui; Zhao, Yi; Liu, Liangbin; Lee, Shuit-Tong; Shao, Mingwang, E-mail: wxlthefirst@gmail.com, E-mail: xuegi@nju.edu.cn, E-mail: mwshao@suda.edu.cn [Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices and Collaborative Innovation, Center of Suzhou Nano Science and Technology, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou 215123 (China); Wang, Xiaoliang, E-mail: wxlthefirst@gmail.com, E-mail: xuegi@nju.edu.cn, E-mail: mwshao@suda.edu.cn; Xue, Gi, E-mail: wxlthefirst@gmail.com, E-mail: xuegi@nju.edu.cn, E-mail: mwshao@suda.edu.cn [State Key Laboratory of Co-ordination Chemistry, Department of Polymer Science and Engineering, Nanjing University, No. 20, Hankou Road, Nanjing 210093 (China)

    2014-01-20

    The effect of gamma ray irradiation on silicon nanowires was investigated. Here, an additional defect emerged in the gamma-ray-irradiated silicon nanowires and was confirmed with electron spin resonance spectra. {sup 29}Si nuclear magnetic resonance spectroscopy showed that irradiation doses had influence on the Q{sup 4} unit structure. This phenomenon indicated that the unique core/shell structure of silicon nanowires might contribute to induce metastable defects under gamma ray irradiation, which served as a satisfactory model to investigate defects at the interface of Si/SiOx.

  19. Modified the optical and electrical properties of CR-39 by gamma ray irradiation

    A.M. Abdul-Kader

    2014-07-01

    Full Text Available The radiation technique is a useful technology technique to induce suitable modifications of the polymeric materials. In the present work, poly allyl diglycol carbonate (CR-39 solid state nuclear track detector samples were irradiated using different doses (150–950 kGy of gamma ray irradiations. The effect of gamma ray irradiations on the optical and electrical, properties of CR-39 was investigated. The obtained results showed a decrease in the optical energy gap with increasing the gamma dose. Increase in the numbers of carbon atoms (N in a formed cluster with increasing the irradiation dose was observed. Meanwhile, an increase in the Ac conductivity was obtained with increasing the gamma dose. Also, the variation in the dielectric constant and loss with irradiation dose was studied at the room temperature. The results indicate that the gamma ray irradiations in the dose range 150–950 kGy enhance the optical and electrical properties of the CR-39 polymer samples.

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

    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)

  1. Physico-chemical characterization of gamma rays irradiated crotamine

    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 60Co 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)

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

    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

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

    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)

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

    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.

  5. Sensitivity of P-Channel MOSFET to X- and Gamma-Ray Irradiation

    Milić Pejović

    2013-01-01

    Full Text Available Investigation of Al-gate p-channel MOSFETs sensitivity following irradiation using 200 and 280 kV X-ray beams as well as gamma-ray irradiation of 60Co in the dose range from 1 to 5 Gy was performed in this paper. The response followed on the basis of threshold voltage shift and was studied as a function of absorbed dose. It was shown that the most significant change in threshold voltage was in the case of MOSFET irradiation in X-ray fields of 200 kV and when the gate voltage was +5 V. For practical applications in dosimetry, the sensitivity of the investigated MOSFETs was also satisfactory for X-ray tube voltage of 280 kV and for gamma rays. Possible processes in gate oxide caused by radiation and its impact on the response of MOSFETs were also analyzed in this paper.

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

    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.

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

    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

  8. Gamma-ray irradiation of a boreal forest ecosystem

    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

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

    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

  10. Effect of gamma-ray and electron irradiation on the response of solid-state track detectors

    Specimens of muscovite mica were first exposed to fission fragments and then to various gamma-ray fields from a 60Co source ranging from 1.9 x 103 to 1.6 x 104 Mrad dose. The results show that the average etched width of fission-fragment tracks decreases with increasing gamma-ray dose. Shallow pits were observed in etched specimens when the gamma-ray dose exceeded 5 x 103 Mrad. Numerous shallow etch pits caused by the gamma-ray irradiation interfered with the observation of fission tracks in the specimens. No shallow etch pits were observed in the specimen annealed for 100 min at 6000C before the gamma-ray irradiation. Pre-annealing extends the ''safety limits'' of gamma background below which muscovite mica can be used to observe fission tracks without any gamma-ray interference. Gamma-ray and electron irradiation caused significant increase of the resistance to thermal decomposition of muscovite mica. The resistance increased markedly in the dose range from 5 x 103 to 8 x 103 Mrad. These phenomena suggest the use of mica to assess radiation doses of gamma rays and electrons up to several thousand megarads. (author)

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

    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.

  12. High energy irradiations simulating cosmic-ray-induced planetary gamma ray production. I - Fe target

    Metzger, A. E.; Parker, R. H.; Yellin, J.

    1986-01-01

    Two thick Fe targets were bombarded by a series of 6 GeV proton irradiations for the purpose of simulating the cosmic ray bombardment of planetary objects in space. Gamma ray energy spectra were obtained with a germanium solid state detector during the bombardment, and 46 of the gamma ray lines were ascribed to the Fe targets. A comparison between observed and predicted values showed good agreement for Fe lines from neutron inelastic scattering and spallation reactions, and less satisfactory agreement for neutron capture reactions, the latter attributed to the difference in composition between the Fe target and the mean lunar abundance used in the modeling. Through an analysis of the irradiation results together with continuum data obtained in lunar orbit, it was found that 100 hours of measurement with a current instrument should generate a spectrum containing approximately 20 lines due to Fe alone, with a 2-sigma sensitivity for detection of about 0.2 percent.

  13. One-step synthesis of graphene-Pt nanocomposites by gamma-ray irradiation

    Tokai, Akihiro; Okitsu, Kenji; Hori, Fuminobu; Mizukoshi, Yoshiteru; Iwase, Akihiro

    2016-06-01

    We developed a one-step gamma-ray irradiation method to synthesize nanocomposites composed of graphene and Pt nanoparticles from aqueous solution containing graphene and Pt(IV) complex ions in the presence of 2-propanol (IPA) or sodium dodecyl sulfate (SDS). It was confirmed that gamma-ray irradiation provided carbonyl groups on graphene and Pt nanoparticles formed from the radiolytic reduction of Pt(IV) complex ions were deposited onto the carbonyl modified graphene. In the presence of IPA, small Pt nanoparticles were deposited on graphene, but large Pt nanoparticles were deposited in the presence of SDS: the size of Pt nanoparticles formed was larger in the presence of SDS than IPA. Based on the results, formation and deposition mechanisms of Pt nanoparticles were proposed.

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

    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)

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

    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 γ-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)

  16. Economic effectiveness of irradiation with gamma rays on maize grains

    Gamma irradiation of maize grains before sowing increses the yield and improves the quality of agricultural produce. The positive results consist in the net income from silage maize from 45 to 85 per ha and from the grain maize from 85 to 109,9 per ha; the level of raw protein from the silage maize with 11,30% and from the grain maize with 6 to 12%; the level of feed units from the silage maize with 5 to 13% and from grain maize with 6 to 12%. Such direct effect in the same time is a stimulating one and raises the effectiveness of the animal production due to the better feeding of animals

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

    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

  18. Removal of endocrine disruptors PAEs in drinking water by gamma-ray irradiation

    Phthalic acid esters (PAEs) belong to environmental endocrine disruptor. The dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-n-butyl phthalate (DBP) were selected for the radiation study. The removal efficiencies of DMP, DEP and DBP in drinking water by gamma-ray irradiation are discussed. The results show that these PAEs could be efficiently removed by gamma-ray irradiation. The removal efficiencies of DMP, DEP and DBP (12 mg/L) in aqueous solutions by 0.8 kGy gamma-ray treatment were 96.6%, 94.5% and 86.2%. The absorbed dose needed for the removal of total carbon in aqueous solutions was much larger than the doses for PAEs degradation. When 2 kGy was selected, the removal efficiencies of TC for DMP, DEP and DBP were only 23.6%, 14.3% and 12.9%. The study results also show that the radiation degradation reaction of PAEs should be divided into two stages: low dose addition reaction and high dose ring-opening reaction. This study is of significance in the disposal of micro-polluted drinking water. (authors)

  19. Measurement and calculation of characteristic prompt gamma ray spectra emitted during proton irradiation.

    Polf, J C; Peterson, S; McCleskey, M; Roeder, B T; Spiridon, A; Beddar, S; Trache, L

    2009-11-21

    In this paper, we present results of initial measurements and calculations of prompt gamma ray spectra (produced by proton-nucleus interactions) emitted from tissue equivalent phantoms during irradiations with proton beams. Measurements of prompt gamma ray spectra were made using a high-purity germanium detector shielded either with lead (passive shielding), or a Compton suppression system (active shielding). Calculations of the spectra were performed using a model of both the passive and active shielding experimental setups developed using the Geant4 Monte Carlo toolkit. From the measured spectra it was shown that it is possible to distinguish the characteristic emission lines from the major elemental constituent atoms (C, O, Ca) in the irradiated phantoms during delivery of proton doses similar to those delivered during patient treatment. Also, the Monte Carlo spectra were found to be in very good agreement with the measured spectra providing an initial validation of our model for use in further studies of prompt gamma ray emission during proton therapy. PMID:19864704

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

    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)

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

    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)

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

    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)

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

    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

  4. Effect of slow irradiation of gamma rays on growth, yield and quality of Coleus forskohlii briq

    Terminal cuttings of coleus cv Garmai is slowly irradiated by using lead filter in the gamma chamber. It has been observed that LD50 of gamma rays was observed at 40Gy dose. Similarly the LD50 for EMS was 1.00 %. Based on this data treatments were formulated in Randomized Block Design and the terminal cuttings were planted in the main field for observation. The results of the study V1M1 indicated that the combined effect of mutagens at higher dosage shows reduced growth characters than the untreated control. The treatment with 50Gy gamma rays + 0.5% EMS exhibited maximum number of tubers (25.50) and maximum length of tubers (17.60 cm) than all other treatments. Maximum fresh and dry weight of tubers (580.50 and 71.20 g) was noticed by the untreated control. The maximum forskolin content (0.66 %) was exerted by the treatment 20Gy gamma rays + 0.5% EMS. However, most of other treatments exhibited same forskolin content (0.42%). The secondary shoots were considered as the second vegetative generation. Secondary shoots were obtained by cutting back the primary shoot and planted for the study of V2M1 generation. The data on plant height expressed at higher side than that earlier generation. The quality parameters like essential oil (0.09%) and total alkaloids (1.05%) was greater at very high doses of mutagen. However, the occurrence of forskolin mutant was stabilized over the generations in 20Gy gamma rays + 1.00% EMS treatment. From the study it was inferred that sudden exposure of materials causes more lethality with poor field establishment and the chance of occurrence of mutants were comparatively lesser. (author)

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

    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

  6. Chemical and physical changes of packaging materials for food by gamma-ray irradiation

    Kawamura, Yoko; Yamada, Takashi [National Inst. of Health Sciences, Tokyo (Japan)

    2000-02-01

    Film and sheet of polyethylene and polystyrene added with BHT, Irganox 1076, Irgafos 168 and Irganox 1010 as antioxidant were treated by gamma-ray irradiation. The change of additive residues, monomer and decomposition products of additives, the tensile strength and change of tone and odor were studied. Polystyrene was the most stable for irradiation. Polypropylene products and large amount of decomposition products indicated very decrease of tensile strength. Polyethylene was more stable than polypropylene, but yellowing was very large. Acetic acid, propion acid, 2-butanone and 2, 4-penyanedione in the decomposition products were controlled by adding antioxidants. Their irradiated decompositions, DTBBQ and 2, 4-DP, were observed. Decreasing of the tensile strength of polypropylene was improved by addition of Irganox 1010 and Irgafos 168. The antioxidants were decreased by irradiation, especially BHC and Irgafos 168. (S.Y.)

  7. Chemical and physical changes of packaging materials for food by gamma-ray irradiation

    Film and sheet of polyethylene and polystyrene added with BHT, Irganox 1076, Irgafos 168 and Irganox 1010 as antioxidant were treated by gamma-ray irradiation. The change of additive residues, monomer and decomposition products of additives, the tensile strength and change of tone and odor were studied. Polystyrene was the most stable for irradiation. Polypropylene products and large amount of decomposition products indicated very decrease of tensile strength. Polyethylene was more stable than polypropylene, but yellowing was very large. Acetic acid, propion acid, 2-butanone and 2, 4-penyanedione in the decomposition products were controlled by adding antioxidants. Their irradiated decompositions, DTBBQ and 2, 4-DP, were observed. Decreasing of the tensile strength of polypropylene was improved by addition of Irganox 1010 and Irgafos 168. The antioxidants were decreased by irradiation, especially BHC and Irgafos 168. (S.Y.)

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

    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

  9. Borohydride-reducible components in soluble collagen irradiated with gamma rays in solution

    Irradiation with 100 krad of gamma rays of neutral-soluble rat skin collagen decreased the content of aldol cross-links by a factor of three, whereas it did not affect the content of allysine. On reduction with tritiated sodium borohydride, five new components were detected showing different stability towards acid and alkali. (author) tetracycline. The results of kinetic and autoradiographic studies and microscopical analysis of bone preparations suggest that stable strontium inhibits the mineralization of newly formed bone tissue without affecting the physicochemical processes related to ion exchange. (author)

  10. Safeguards on the depleted uranium used in gamma ray irradiator as shield material

    Depleted uranium used in gamma ray irradiator as the shielding material was not completely investigated and properly reported by the Atomic Energy Act until now, The IAEA required to report the status of the companies using small amount of uranium and information for 42 NDT companies was declared in 1999. And IAEA inspector visited some company to confirm their declarations. The Additional protocol proposed as the strengthened safeguards system by the IAEA, which was ratified through the national assembly on February 9, 2004, and was entered into force on February 19, 2004. The government is investigating the amount, purpose and location of depleted uranium in the area of non-nuclear use.

  11. Synergism of. gamma. -ray irradiation and temperature on the deterioration of flame-retardant cables

    Okamoto, Shinichi (Radiation Center of Osaka Prefecture, Sakai (Japan)); Katayama, Shiro; Takeya, Chikashi; Hayakawa, Tsutomu; Iwata, Seiji

    1981-03-01

    Characteristic changes of frame-retardant cables, C*V and P*N having excellent resistance to heating and ..gamma..-ray irradiation for nuclear power generating stations, were studied under combined environments of ..gamma..-ray irradiation (2 x 10 sup(g) r and less) and elevated temperature (150/sup 0/C and 170/sup 0/C). They included the changes in appearance, elongation, insulation resistance, AC breakdown voltage, and power factor. The synergistic effects were observed in them. That is, the synergism of PVC (V) and Neoprene rubber (N) appeared after irradiation with 2.5 x 10/sup 7/ r at 150/sup 0/C, while that of XLPE (C*) and EPR (P*) appeared under conditions of heavier exposure doses at higher temperature. These test conditions were more severe than normal service condition in the plant which was assumed as 40 years at 70/sup 0/C and total dosage of 70 mega-rads. The mechanism of deterioration in characteristics of the cables in this test may be different from that of aging in the plant.

  12. BROCCOLI Spears Yield Affected By GAMMA Rays Irradiated Seeds And Foliar Application Of Some Growth Regulators

    Two field experiments were carried out during 2004/2005 and 2005/2006 winter growing seasons at the experimental farm of Nuclear Research Centre, Atomic Energy Authority, Inshas, Egypt.The experiments were conducted to study the effect of pre-sowing broccoli seeds (cv. F1 175) irradiated with different doses of gamma rays (2, 3 and 4 Gy). The plants were sprayed with GA3 at rate of 50 ml/liter/fed and 20 ml/liter/fed for NAA. Main spear fresh and dry weight per plant, total spears fresh and dry weight per plant, total spears yield, ascorbic acid, TSS, carbohydrates, total chlorophyll, NPK and total protein content of spears were evaluated. The results showed that broccoli seeds irradiated with gamma rays up to 4 Gy pre-sowing increased the abovementioned parameters with different magnitudes comparing with the non-irradiated control plants except spears N, P and protein contents showed decrease in their values comparing with un-treated plants.It could be concluded that the foliar application of GA3 and NAA on broccoli spears increased all the abovementioned parameters, except spears N, P and protein contents showed decrease in their values.

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

    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)

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

    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%

  15. Study on influences of rabbit thyroids irradiated by 60Co-gamma ray

    Effects of radiotherapy on the thyroid gland were evaluated with rabbits. gamma ray of 3.000R was irradiated locally. Thyroid hormone T4 and T3 were assayed by RIA method, blood flow was estimated by sup(99m)Tc-MAA uptake, and histopathological changes were also studied. T4 and T3 markedly decreased one day after irradiation, and a decrease of T4 was greater than that of T3. T4 and T3 continued to decrease until 3 days after irradiation, then, began to increase slowly, 7 days after irradiation, and almost returned to the initial level 14 days after irradiation. T4 kept the level thereafter with little changes, but T3 tended to decrease. sup(99m)Tc uptake decreased sharply one day after irradiation and continued to decrease gradually. It began to increase slowly 28 days after and almost returned to about 2/3 the initial level 56 days after irradiation. Histopathological study revealed no remarkable changes except degeneration and proliferation of follicular epithelium 14 days after irradiation. Changes in T4 and T3 due to decreased thyroid function after irradiation was comparatively parallel to histopathological changes. However, changes in blood flow and those in T4 and T3 were parallel with each other only at the time immediately after irradiation and at the end of the follow-up. This tendency was marked in T4. (Ueda, J.)

  16. Electron beam and gamma ray irradiated polymer electrolyte films: Dielectric properties

    S. Raghu

    2016-04-01

    Full Text Available In this study, polymer electrolyte films were irradiated with electron beam (EB and Gamma ray (GR at 50 and 150 kGy. The induced chemical changes in films due to irradiations have been confirmed from the Fourier Transform Infra red (FT-IR spectra. The X-ray Diffractometry (XRD results show that crystallinity decreases by ∼20% in EB and ∼10% in GR irradiated films respectively compared to non-irradiated film. The micro structural arrangement was investigated by Scanning Electronic Microscopy (SEM and the images reveal that there is a substantial improvement in the surface morphology in irradiated films. The real (ε′ and imaginary (ε″ dielectric constant and AC conductivity are found to increase with increase in irradiation dose. Improved dielectric properties and conductivity (1.74 x 10−4 & 1.15 x 10−4 S/cm, respectively, for EB and GR irradiated films at room temperature after irradiation and it confirm that EB and GR irradiation can be simple and effective route to obtaining highly conductive polymer electrolytes. From this study it is confirm that EB is more effectiveness than GR irradiation.

  17. Hydrogen loss from elastomers subjected to ion irradiation

    Research highlights: → Hydrogen release from irradiated elastomers is more pronounced with respect to polymers. → Hydrogen release from irradiated elastomers is governed by inelastic energy losses (ionization). → Hydrogen content in irradiated elastomers saturates at about 10 at.%. - Abstract: Hydrogen release from various elastomers upon irradiation with H+, He+ and Ar+ ions has been studied using nuclear reaction analysis (NRA) method. A massive loss of hydrogen atoms upon irradiation has been noted, the results point to the saturation of hydrogen content at about 10 at.%. The analysis of the experimental data indicates that the hydrogen release is controlled by inelastic collisions between ions and target electrons.

  18. The influence of irradiation of gamma-rays on the pulping and paper making, (4)

    The influence of gamma-irradiation on the beating properties of unbleached kraft pulps was studied, and the changes of the mechanical and chemical properties of the sheet made from those pulps were also investigated. The results obtained were as follows: (1) When the unbeaten pulp was treated with gamma-ray, the degree of polymerization of cellulose was decreased rapidly and the formation of aldehyde and carboxyl groups in pulp was observed in addition to that the beating time of irradiated pulps was reduced comparing with non-irradiated pulp. These effects increased roughly in proportion to the radiation dose. (2) Gamma-irradiation was more effective in wet state (moisture content = 70 - 80%) than air dry state. This may be due to the degradation products of water by gamma-irradiation. (3) The mechanical properties (breaking length, tear and burst factors) of the sheets made from irradiated pulps were considerably deteriorated at 107R, but there was a slight deterioration up to 106R. (4) Comparing the result of the mechanical properties, the strengths of the various sheets were shown in the following order: the sheet irradiated after paper making gt the sheet irradiated before beating (air dry state) gt the sheet irradiated before beating (wet state). (author)

  19. Study on 99Mo production by solution irradiation method (2). Characterization of aqueous molybdate solutions under gamma-ray irradiation

    The solution irradiation method is proposed as a new production technique for 99Mo, which is the parent nuclide of 99mTc used as a radiopharmaceutical. In this new method, an aqueous molybdenum solution is irradiated with neutrons in a nuclear reactor, and more efficient and lower-cost 99Mo production than conventional 99Mo production can be realized by using the 98Mo (n,γ) 99Mo reaction and the molybdenum adsorbent of PZC. Aiming at the practical application of this method, unirradiation tests, gamma-ray irradiation tests, and neutron irradiation tests should be needed in order to characterize the aqueous molybdenum solution as the irradiation target. In the present study, using two kinds of aqueous molybdate solutions (an aqueous ammonium molybdate solution and an aqueous potassium molybdate solution) selected as candidates for the irradiation target of the new method, the compatibility between the solutions and structural materials, the chemical stability, the circulation characteristics, the radiolysis, and the gamma heating of the solutions were investigated under gamma-ray irradiation. In addition, the integrity of PZC was investigated under gamma-ray irradiation. As a result, the following were found: 1) the compatibility between the solutions and stainless steel is very well, 2) the solutions are chemically stable and have a smooth circulation, 3) the ratios of hydrogen in the gases generated by the radiolysis of the solutions are higher than that of pure water, 4) the effect of gamma heating on the solutions is the same level as that on pure water, and 5) the integrity of PZC is maintained. (author)

  20. Effects of gamma ray irradiation on the struvite crystallization of livestock wastewater

    Yoo, Byeong Hak; Jo, Seong Hui; Lee, Myun Joo; Kim, Tak Hyun [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-12-15

    The struvite crystallization was applied to remove NH{sub 4}{sup +} in livestock wastewater. The ammonium ions can be very toxic to the aquatic creatures. In this experiments, the livestock wastewater from Gongju livestock wastewater treatment plant was used. The behaviors of various parameters such as pH, mole ratio of Mg{sup 2+} : NH{sub 4}{sup +}: PO{sub 4}{sup 3-} and reaction temperature for struvite crystallization of livestock wastewater and the effect of gamma ray irradiation were evaluated. As results, for the pH variation, the NH{sub 4}{sup +} removal efficiency showed the highest, 88%, at pH 9 {approx} 9.25. The removal efficiency of NH{sub 4}{sup +}, Mg{sup 2+} and PO{sub 4}{sup 3-} was showed highest when same molar ratio of Mg{sup 2+} and PO{sub 4}{sup 3-} were applied. The NH{sub 4}{sup +} removal efficiency showed 82% at 7 .deg. C, and 90% at 30 .deg. C, with temperature. When the wastewater was irradiated with 20 kGy of gamma ray, NH{sub 4}{sup +} was removed as much as 83%.

  1. Digested livestock wastewater treatment using gamma-ray irradiation and struvite crystallization

    Kim, Tak Hyun; Lee, Sang Ryul; Nam, Youn Ku; Lee, Myun Joo [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-06-15

    Livestock wastewater generally contains high strength of organics (COD), ammonia nitrogen (NH{sub 4}{sup +} -N), phosphate phosphorus (PO{sub 4}{sup 3-} -P) and suspended solids. It is very difficult to treat by conventional wastewater treatment techniques. In this study, struvite crystallization was carried out to treat the digested livestock wastewater. 1.0 :1.2 :1.2 was determined as an optimal NH{sub 4}+ :Mg{sup 2+} : PO{sub 4}{sup 3-} mol ratio of struvite crystallization. For the digested livestock wastewater, COD, NH{sub 4}{sup +} -N and PO{sub 4}{sup 3-} -P removal efficiencies by struvite crystallization were 72.4%, 98.9%, and 74.8%, respectively. Gamma-ray irradiation was carried out prior to struvite crystallization of livestock wastewater. The enhancement of struvite crystallization efficiency could be obtained by the pretreatment of gamma-ray irradiation due to the decrease of COD, NH{sub 4}{sup +} -N and PO{sub 4}{sup 3-} -P concentration.

  2. Radiation-induced degradation of cyclohexanebutyric acid in aqueous solutions by gamma ray irradiation

    Jia, Wenbao; He, Yanquan; Ling, Yongsheng; Hei, Daqian; Shan, Qing; Zhang, Yan; Li, Jiatong

    2015-04-01

    The radiation-induced degradation of cyclohexanebutyric acid under gamma ray irradiation was investigated. Degradation experiments were performed with 100 mL sealed Pyrex glass vessels loaded with 80 mL of cyclohexanebutyric acid solutions at various initial concentrations of 10, 20, and 40 mg L-1. The absorbed doses were controlled at 0, 0.65, 1.95, 3.25, 6.5, 9.75, and 13 kGy. The results showed that gamma ray irradiation could effectively degrade cyclohexanebutyric acid in aqueous solutions. The removal rate of cyclohexanebutyric acid increased significantly with the increase of absorbed dose and the decrease of its initial concentration. At the same time, the removal of chemical oxygen demand (COD) was as effective as that of cyclohexanebutyric acid. The kinetic studies showed that the degradation of cyclohexanebutyric acid followed pseudo first-order reaction. Above all, the proposed mechanism obtained when NaNO2, NaNO3 and tert-butanol were added showed that the •OH radical played a major role in the gamma degradation process of cyclohexanebutyric acid, while •H and eaq- played a minor role in the gamma degradation process. The degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS) during cyclohexanebutyric acid degradation.

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

    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)

  4. Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

    Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

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

    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)

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

    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

  7. Detection of irradiated fresh fruits treated by e-beam or gamma rays

    Marin-Huachaca, Nélida Simona; Lamy-Freund, Maria Tereza; Mancini-Filho, Jorge; Delincée, Henry; Villavicencio, Anna Lúcia C. H.

    2002-03-01

    Since about 1990, the amount of commercially irradiated food products available worldwide has increased. Commercial irradiation of foods has been allowed in Brazil since 1973 and now more than 20 different food products are approved. Among these products are a number of fresh fruits which may be irradiated for insect disinfestation, to delay ripening and to extend shelf-life. Today, there is a growing interest to apply radiation for the treatment of fruits instead of using fumigation or e.g. vapour-heat treatments, and an increased international trade in irradiated fruits is expected. To ensure free consumer choice, methods to identify irradiated foods are highly desirable. In this work, three detection methods for irradiated fruits have been employed: DNA Comet Assay, the half-embryo test and ESR. Both electron-beam (e-beam) and gamma rays were applied in order to compare the response with these two different kinds of radiation. Fresh fruits such as oranges, lemons, apples, watermelons and tomatoes were irradiated with doses in the range 0, 0.50, 0.75, 1.0, 2.0 and 4.0kGy. For analysis, the seeds of the fruits were utilized. Both DNA Comet Assay and the half-embryo test enabled an easy identification of the radiation treatment. However, under our conditions, ESR measurements were not satisfactory.

  8. Detection of irradiated fresh fruits treated by e-beam or gamma rays

    Since about 1990, the amount of commercially irradiated food products available worldwide has increased. Commercial irradiation of foods has been allowed in Brazil since 1973 and now more than 20 different food products are approved. Among these products are a number of fresh fruits which may be irradiated for insect disinfestation, to delay ripening and to extend shelf-life. Today, there is a growing interest to apply radiation for the treatment of fruits instead of using fumigation or e.g. vapour-heat treatments, and an increased international trade in irradiated fruits is expected. To ensure free consumer choice, methods to identify irradiated foods are highly desirable. In this work, three detection methods for irradiated fruits have been employed: DNA Comet Assay, the half-embryo test and ESR. Both electron-beam (e-beam) and gamma rays were applied in order to compare the response with these two different kinds of radiation. Fresh fruits such as oranges, lemons, apples, watermelons and tomatoes were irradiated with doses in the range 0, 0.50, 0.75, 1.0, 2.0 and 4.0 kGy. For analysis, the seeds of the fruits were utilized. Both DNA Comet Assay and the half-embryo test enabled an easy identification of the radiation treatment. However, under our conditions, ESR measurements were not satisfactory

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

    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

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

    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

  11. Effect of gamma irradiation dose on the fabrication of α-elastin nanoparticles by gamma-ray crosslinking

    Nanoparticles were prepared utilizing the thermosensitive aggregation of α-elastin and gamma-ray crosslinking. We investigated the effect of the α-elastin irradiation doses to verify the yield of crosslinked nanoparticles. Aqueous solution of α-elastin (10 mg/ml) was used for the aggregation on raising temperature above its cloudy point (CP), followed by gamma-ray crosslinking. A slow heating process (1.9 oC/min) effectively led to aggregation of polypeptide and irradiation with more than 15 kGy yielded stable crosslinked nanoparticles with diameters less than ca. 200 nm and a narrow size distribution.

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

    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 37°C. Agglutination titer of positive immune chicken serum against gamma-ray irradiate Salmonella pullorum were as 320 approximately 640x. (author).

  13. Reaction of nuclear graphite with oxygen under gamma-ray irradiation

    The reaction of four kinds of nuclear graphites with oxygen under Co-60 gamma-ray irradiation were examined in the gas flow at 1atm, at temperatures 25 - 2040C and gamma dose rates 3.8 - 12.5 x 105R/hr. Air and oxygen diluted with helium were also used as the atmosphere. Radiation induced oxidation rates of the graphites in pure oxygen at dose rate 12.5 x 105R/hr were found to be 6.6 - 7.5 x 108g/g.hr, showing little differences between the graphites. Over all oxidation rate of the graphites increased with temperature, but the radiation induced rate kept constant with temperature. The increase of the over all rate at high temperatures was concluded to be due to the increase in thermally induced oxidation rate. The radiation induced oxidation rate was expressed as R = 8.3 x 10-12(D)sup(0.64), where R is the radiation induced oxidation rate in g/g.hr and D is the dose rate in R/hr. Oxidation rate of the graphite in air was about 40% of that in pure oxygen, and that in the oxygen diluted with helium was constant 15% in 0.2 - 1.0 vol.% oxygen. It was shown that the gamma-rays in a reactor would little influence oxidation of the structural graphite at high temperatures. (author)

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

    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 32±2oC 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

    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

    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

  17. Radiation-induced degradation of cyclohexanebutyric acid in aqueous solutions by gamma ray irradiation

    The radiation-induced degradation of cyclohexanebutyric acid under gamma ray irradiation was investigated. Degradation experiments were performed with 100 mL sealed Pyrex glass vessels loaded with 80 mL of cyclohexanebutyric acid solutions at various initial concentrations of 10, 20, and 40 mg L−1. The absorbed doses were controlled at 0, 0.65, 1.95, 3.25, 6.5, 9.75, and 13 kGy. The results showed that gamma ray irradiation could effectively degrade cyclohexanebutyric acid in aqueous solutions. The removal rate of cyclohexanebutyric acid increased significantly with the increase of absorbed dose and the decrease of its initial concentration. At the same time, the removal of chemical oxygen demand (COD) was as effective as that of cyclohexanebutyric acid. The kinetic studies showed that the degradation of cyclohexanebutyric acid followed pseudo first-order reaction. Above all, the proposed mechanism obtained when NaNO2, NaNO3 and tert-butanol were added showed that the ∙OH radical played a major role in the gamma degradation process of cyclohexanebutyric acid, while ∙H and eaq− played a minor role in the gamma degradation process. The degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS) during cyclohexanebutyric acid degradation. - Highlights: • Gamma irradiation was efficient for removing cyclohexanebutyric acid from water. • The degradation kinetics of cyclohexanebutyric acid followed pseudo first-order reaction. • OH radical played a major role for oxidative degradation. • Some possible intermediate products were identified

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

    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)

  19. A study on the irradiation effect of 60Co gamma ray on dental polymethylmethacrylate bonded parts

    In this paper we describe an experimental study on the irradiation effect of 60Co gamma ray on dental polymethylmethacrylate (P.M.M.A.) welding part, hot and cold polymerizing adhesion part. It was found that from the result of tension test, no remarkable change of mechanical property is found with any of the bonded parts by the irradiation dose up to 107 r., and no deterioration by irradiation is observed. And then, according to the results of bending test, it is found that, although the three different bonded parts have different features, the strength of the welded part and of the part adhered by hot polymerizing adhesive becomes lower by irradiation, and bending strength of the three parts converges on 6 kg/mm2 after irradiation within a range of 106 - 107 r.. Joint efficiency (= bonded part strength/base material strength) of 65 - 75% in tension and 50 - 62% in bending can be adopted. Fracture of the base material and of the Welded part are similar, and prove high bonding strength. (author)

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

    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)

  1. Comparative nephrotoxicity of native or Co-60 gamma rays irradiated crotoxin in mice

    Snake venoms are complex mixtures of proteins and peptides with a wide spectrum of physiological targets such as the blood coagulation and cardiovascular systems and the motor end plate among others. Acute renal failure is a common complication in accidents with the South American rattlesnake. The toxin involved in this pathology is the crotoxin, a major component of the venom in terms of concentration and toxicity. Snake venoms, when irradiated with 60Co gamma rays present a significant decrease in toxicity while the immunogenic properties of its components are preserved. The use of irradiated venom is an attractive alternative for antisera production since it might reduce the appearance of renal lesions improving the welfare and lifespan of those animals employed on antivenom production. At the present work, we have compared the effects of native and irradiated crotoxin on the mice renal function. Tubular lesions were observed in all the samples from the animal group injected with native crotoxin. Animals injected with the irradiated toxin presented alteration only after 30 minutes and 1 hour after injection. These data suggest that the onset of the renal lesions is delayed and that the severity of the lesions might be lower when using irradiated crotoxin. (author)

  2. Degradation and annealing studies on gamma rays irradiated COTS PPD CISs at different dose rates

    Wang, Zujun; Ma, Yingwu; Liu, Jing; Xue, Yuan; He, Baoping; Yao, Zhibin; Huang, Shaoyan; Liu, Minbo; Sheng, Jiangkun

    2016-06-01

    The degradation and annealing studies on Colbalt-60 gamma-rays irradiated commercial-off-the-shelf (COTS) pinned photodiode (PPD) CMOS image sensors (CISs) at the various dose rates are presented. The irradiation experiments of COTS PPD CISs are carried out at 0.3, 3.0 and 30.0 rad(Si)/s. The COTS PPD CISs are manufactured using a standard 0.18-μm CMOS technology with four-transistor pixel PPD architecture. The behavior of the tested CISs shows a remarkable degradation after irradiation and differs in the dose rates. The dark current, dark signal non-uniformity (DSNU), random noise, saturation output, signal to noise ratio (SNR), and dynamic range (DR) versus the total ionizing dose (TID) at the various dose rates are investigated. The tendency of dark current, DSNU, and random noise increase and saturation output, SNR, and DR to decrease at 3.0 rad(Si)/s are far greater than those at 0.3 and 30.0 rad(Si)/s. The damage mechanisms caused by TID irradiation at the various dose rates are also analyzed. The annealing tests are carried out at room temperature with unbiased conditions after irradiation.

  3. Comparative nephrotoxicity of native or Co-60 gamma rays irradiated crotoxin in mice

    Rocha, Andre Moreira; Alves, Glaucie J.; Aires, Raquel da Silva; Turibio, Thompson O.; Thomazi, Gabriela O. Coelho; Spencer, Patrick J.; Nascimento, Nanci do, E-mail: andrerocha@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Nascimento-Rocha, Josefa M.; Magalhaes Filho, Asterio Souza, E-mail: 0304@prof.itpacporto.com.br [Instituto Tocantinense Presidente Antonio Carlos Porto (ITPAC), Porto Nacional, TO (Brazil)

    2015-07-01

    Snake venoms are complex mixtures of proteins and peptides with a wide spectrum of physiological targets such as the blood coagulation and cardiovascular systems and the motor end plate among others. Acute renal failure is a common complication in accidents with the South American rattlesnake. The toxin involved in this pathology is the crotoxin, a major component of the venom in terms of concentration and toxicity. Snake venoms, when irradiated with {sup 60}Co gamma rays present a significant decrease in toxicity while the immunogenic properties of its components are preserved. The use of irradiated venom is an attractive alternative for antisera production since it might reduce the appearance of renal lesions improving the welfare and lifespan of those animals employed on antivenom production. At the present work, we have compared the effects of native and irradiated crotoxin on the mice renal function. Tubular lesions were observed in all the samples from the animal group injected with native crotoxin. Animals injected with the irradiated toxin presented alteration only after 30 minutes and 1 hour after injection. These data suggest that the onset of the renal lesions is delayed and that the severity of the lesions might be lower when using irradiated crotoxin. (author)

  4. The effect of red ginseng extract on superoxide dismutase activity in the kidney of gamma-ray irradiated mice

    This study was prepared to observe the change of enzyme activities in kidney treated with red ginseng extract in the gamma ray irradiated mice. Determine the activity of SOD, peroxidase, catalase in the kidney a period of 1 day, 2 day, 3 day, 4 day, 5 day after a saline injection or injection of red ginseng extract or gamma ray irradiated group into four classify. The activity SOD and catalase showed a tendency to increase and recovery at the early state but pay no regard. Where ase, the activity of peroxide restored and increased pay regard. A physiological saline injection group after gamma ray irradiation showed a tendency to diminish after remarkable increase of activity of SOD, peroxidase and catalase than control group. Injection group of red ginseng extract after gamma ray irradiation observed rapid recovery on activity of SOD, peroxidase, catalase than a saline injection group. Experimental result suggested that injection of red ginseng extract after irradiation have the recovery effect on the changed of activity of SOD, peroxidase and catalase against radiation injury

  5. The effect of red ginseng extract on superoxide dismutase activity in the kidney of gamma-ray irradiated mice

    Park, Yong Soon [Kunsan Vocational College, Kunsan (Korea, Republic of)

    1992-05-15

    This study was prepared to observe the change of enzyme activities in kidney treated with red ginseng extract in the gamma ray irradiated mice. Determine the activity of SOD, peroxidase, catalase in the kidney a period of 1 day, 2 day, 3 day, 4 day, 5 day after a saline injection or injection of red ginseng extract or gamma ray irradiated group into four classify. The activity SOD and catalase showed a tendency to increase and recovery at the early state but pay no regard. Where ase, the activity of peroxide restored and increased pay regard. A physiological saline injection group after gamma ray irradiation showed a tendency to diminish after remarkable increase of activity of SOD, peroxidase and catalase than control group. Injection group of red ginseng extract after gamma ray irradiation observed rapid recovery on activity of SOD, peroxidase, catalase than a saline injection group. Experimental result suggested that injection of red ginseng extract after irradiation have the recovery effect on the changed of activity of SOD, peroxidase and catalase against radiation injury.

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

    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.

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

    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

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

    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

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

    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 (γ-R). The relations between survival and fluence of UV, and survival and absorbed dose of γ-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 γ-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

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

    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.

  11. Ageing evaluation of low voltage cables and insulators with gamma ray irradiation and thermal accelerated ageing tests

    To optimize lifetime prediction method of cables and to understand cable ageing mechanism, ageing evaluation of low voltage cables and insulators with gamma ray irradiation and thermal accelerated ageing tests were conducted. Insulators had no indication of the ageing after 1000 hours of the accelerated ageing tests. (author)

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

    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 mol·L-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

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

    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)

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

    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

  15. X and gamma rays irradiation tests for evaluating performances of Italian dosimetry services

    The ENEA (Italian Agency for New Technologies, Energy and the Environment)-EDP Group (Personal Dosimetry Experts) has already evaluated the reliability of more than 50% of the 70 Italian personal dosimetry services, which agreed to test their dosimeters through X and gamma irradiation in air. Film,TL and both film and TL are used as detectors. The X and gamma rays energy ranges from 30 keV to 1.250 keV (beam defined by ISO 4037). Exposures range from 5.2 10-6 C/kg to 1.3 10-3 C/kg. Some dosimeters have been irradiated with a single energy level and others with two energy levels. For each one of the nearly 4.000 dosimeters already tested, the ratio R has been calculated: R = Xv/Xa where: Xv is the exposure evaluated by the service, Xa is the actual exposure. The R distributions have been analysed for the dosimeters using film or TL as detectors, as a function of irradiation energy and as a function of exposure values. The results obtained by all tested services are commented. Separate comments deal also with possible reasons of the failures to pass the tests

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

    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)

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

    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

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

    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

  19. Minisatellite and HPRT mutations in V79 and human cells irradiated with gamma rays

    The induction of mutations at the Hprt locus and minisatellite sequences was studied in V79 cells, peripheral blood lymphocytes (PBL) and lymphoblastoid cells (CCRF-CEM) exposed to gamma rays. In V79 cells the Hprt mutant frequency increased with dose at least up to 6.0 Gy, whereas the number of HPRT mutant lymphocytes increased up to 3 Gy. Clones derived from single irradiated cells were screened for mutations at minisatellite sequences by DNA fingerprint analysis. In V79 cells, a dose-response curve for minisatellite alterations was obtained up to 4.5 Gy. In contrast, very few mutations at minisatellite sequences (2/137) were detected among clones isolated from PBL of two donors irradiated with 1-4 Gy. Similar results were observed in lymphoblastoid CCRF-CEM cells irradiated with 2-3 Gy (4 mutants/180 clones), suggesting that in human lymphoid cells minisatellite DNA is more stable than in other mammalian and human cell lines. (author)

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

    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)

  1. Radiation chemistry in alanine irradiated with {gamma}-rays and ion beams

    Koizumi, Hitoshi; Ichikawa, Tsuneki; Yoshida, Hiroshi [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering

    1997-01-01

    In order to extend the application of alanine dosimetry, the behavior of free radicals in solid {alpha}-alanine irradiated with {gamma}-rays and with ion beams was studied by electron spin resonance. Stable neutral radicals are produced through the decomposition of originally generated ion radicals in alanine irradiated at 300 K, while at 77 K the ion radicals are stable, and also do not decompose. The rate of the combination reaction of the neutral radicals and of the ion radicals was studied by measuring the saturation behavior of the radical concentration in {gamma}-radiolysis at 300 and at 77 K. The yield of the neutral radicals was compared between 0.5, 1,2 and 3 MeV H{sup +}, 0.5, 1, and 3 MeV He{sup +}, 175 MeV Ar{sup 8+} and 460 MeV Ar{sup 13+} ion irradiations. Dependence of the radical yield on the radiation quality is understood more in terms of the rate of the combination reaction between the ion radicals than with that between the neutral radicals, and has to do with high local dose within the ion tracks. (Author).

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

    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)

  3. Effects of gamma-ray irradiation on leaching of simulated {sup 133}Cs{sup +} radionuclides from geopolymer wasteforms

    Deng, Ning; An, Hao; Cui, Hao, E-mail: cuihao@nju.edu.cn; Pan, Yang; Wang, Bing; Mao, Linqiang; Zhai, Jianping

    2015-04-15

    Highlights: • γ-ray irradiation caused more Cs{sup +} 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 {sup 133}Cs{sup +} 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.

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

    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)

  5. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

    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

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

    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

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

    Xie, Shuibo; Wu, Yuqi; Wang, Wentao; Wang, Jingsong; Luo, Zhiping; Li, Shiyou

    2014-04-01

    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).

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

    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)

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

    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)

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

    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...

  11. Broccoli yield and yield quality as affected by gamma rays seeds irradiation and foliar application of some nutrients

    Two field experiments were carried out during 1999/2000 and 2000/2001 winter growing seasons at the Atomic Energy Authority (AEA) in Inshas, Egypt. The experiment was conducted to study the effect of pre-sowing seeds irradiation with different doses of gamma rays (0, 2, 3 and 4 Gy) and foliar application of different nutrients (Zn, B, S and S+K) on spear diameter, main spear fresh and dry weight per plant, total spear fresh weight per plant, total spear yield besides NPK in leaves at 90 days after transplanting and NPK and total protein content in spears at maturity. In general, exposing broccoli seeds to different gamma ray doses up to 4 Gy prior to sowing increased the above mentioned parameters with different magnitudes comparing with the non-irradiated control plants. There were no significant differences between 3 Gy and 4 Gy treatments during the two growing seasons. With respect to the effect of nutrient application on the studied parameters, all nutrients application significantly increased all the above mentioned parameters. The highest result was detected with B application. Regarding to the interaction of gamma ray with nutrients application, the highest value of all above mentioned parameters was detected with B application and 3 Gy of gamma ray

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

    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)

  13. Comparison of the effects of gamma ray and e-beam irradiation on the quality of minced beef during storage

    This study was conducted to compare the microbiological and physicochemical qualities of minced beef irradiated with gamma ray of e-beam at the absorbed doses from 5 to 20 kGy. The total bacterial counts of minced beef were decreased depending upon the irradiation doses, but sterilizing effect of gamma irradiation was higher than that of e-beam irradiation. The contents of malondialdegyde of minced beef were increased depending upon irradiation doses as well as storage periods (p< 0.05). Volatile basic nitrogen in minced beef was constantly increased during storage, but the increasing rate were retarded by irradiation. The hunter's color values(L*, a* and b*) of gamma or e-beam irradiated minced beef were decreased as irradiation dose increasing. Meanwhile, the quality changes of gamma irradiated samples were faster than e-beam irradiated samples

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

    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)

  15. Breeding of Setonami, a new variety of mat rush by gamma ray irradiation

    A new variety of mat rush, Setonami, was obtained from Asanagi by the following procedure. 24 growing plants of Asanagi were irradiated with the gamma ray from a Co-60 source at the distance of 9 m. The cumulative dose was 68 KR, and the dose rate was 363 R/day. It was carried out in a gamma field at the Institute of Radiation Breeding from April to December, 1963. They were brought back to the Tobu Branch, Hiroshima Prefectural Agricultural Experiment Station, divided into 480 individuals, and planted in a paddy field. Thereafter, they were selectively cultivated by clonal separation from December, 1964. In December, 1969, the cuttings of one of the strains were distributed among the prefectures concerned, and their productivity and local adaptability were tested. It was found in these tests that they were excellent, and they were named Setonami in June, 1982. Although the growth pattern is of a tiller type, Setonami produces long stems exceeding 105 cm with a large number of tillers. It bears very few flowers, and its florescence is short. The dried stems show beautiful luster. The stems are as thick as Asanagi, but supple. The yield of Setonami is more than that of Asanagi. The tatami-facing production with Setonami per unit planted area is more than that of Asanagi, and the quality is superior. (Kako, I.)

  16. Effect that atmospheric pressure exerts to DC tracking of polyethylene irradiated with gamma ray

    In the testing method of tracking resistance carried out generally, particular stipulation is not made on atmospheric pressure. But there is the case that electric and electronic equipments are used in the place of low pressure. The lowering of atmospheric pressure affects the phenomenon of tracking deterioration, and it is sufficiently conceivable that tracking resistance changes. So far, the effect that atmospheric pressure exerts on tracking resistance at the time of applying AC voltage has been mainly studied, however recently, DC voltage has become widely utilized, and the elucidation of DC tracking phenomena has become important. The experiment of irradiating Co-60 gamma ray to polyethylene and obtaining the basic data on the effect that atmospheric pressure exerts to DC tracking using those samples was carried out. The experimental setup, the samples and the tracking resistance test are reported. The relation of the weight loss with atmospheric pressure, the relation of the maximum erosion depth and atmospheric pressure, the measurement of the amount of residual carbide and the tracking resistance using brass electrodes are described. (K.I.)

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

    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

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

    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. (author)

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

    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)

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

    Sharma, G.; Thind, K.S.; Manupriya, -;

    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...

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

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

    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

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

    Wang, C.-K. Chris; Zhang, Xin; Gifford, Ian; Burgett, Eric; Adams, Vince; Al-Sheikhly, Mohamad

    2007-09-01

    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 the 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.

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

    Wang, C-K Chris [Nuclear/Radiological Engineering/Medical Physics Program Neely Research Center, Georgia Institute of Technology, 900 Atlantic Drive, Atlanta, GA 30332-0425 (United States); Zhang Xin [Nuclear/Radiological Engineering/Medical Physics Program Neely Research Center, Georgia Institute of Technology, 900 Atlantic Drive, Atlanta, GA 30332-0425 (United States); Gifford, Ian [Department of Materials and Bioengineering, University of Maryland, College Park, MD 20742-2115 (United States); Burgett, Eric [Nuclear/Radiological Engineering/Medical Physics Program Neely Research Center, Georgia Institute of Technology, 900 Atlantic Drive, Atlanta, GA 30332-0425 (United States); Adams, Vince [Department of Materials and Bioengineering, University of Maryland, College Park, MD 20742-2115 (United States); Al-Sheikhly, Mohamad [Department of Materials and Bioengineering, University of Maryland, College Park, MD 20742-2115 (United States)

    2007-09-07

    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. {sup 252}Cf brachytherapy.

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

    Umar, J.M. [National Atomic Energy Agency, Jakarta (Indonesia). Center for Application of Isotopes and Radiation; Matsuhashi, Shinpei; Hashimoto, Shoji

    1996-03-01

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

    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)

  7. Sterilization experiment of crocidolomia binotalis zeller by gamma ray irradiation and its control application

    Experiments have been conducted to study C. binotalis control initiated with the rearing method and ended with the release of sterile irradiated insects. Rearing of cabbage pest using modified artificial diet of Pieris rapae gave better result compared to that with natural diet. The larval viability was 58% and 25.9% from the artificial and the natural diet respectively. Gamma ray doses of 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4 and 0.45 kGy were introduced to six-day-old sexed pupae in nitrogen and air atmosphere. A 100% sterility on males was obtained at 0.45 kGy in both air and nitrogen atmosphere. 100% sterility on females was found at 0.25 kGy in nitrogen and 0.2 kGy in air atmosphere. The effect of dose on the percentage of sterile and mating competitiveness were not significantly different (P ≥0.05). A significant correlation (r=0.8774) was found between the percentage of fertility and the mating competitiveness of irradiated insects. The lower the fertility of the insects the less mating competitiveness they have. 0.4 kGy was considered to be adequate for sterilization of C. binotalis. It produced a high percentage of sterility besides moderate mating competitiveness, 84.52% and 0.57% respectively. 0.4 kGy seemed to give 3 days shorter longevity of moth than the normal one. The number of F1 larval population was not significantly different if the released insects were either females or males or mixed sexes. The ratio of 9:1 of the sterile and normal insects under laboratory, field-cage, and in the field indicated that the sterile insect technique has the potential to suppress F1 population by about 50% due to the mating competitiveness of the radiosterilized insect still maintained at the level of 0.57. (author). 17 refs

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

    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. The design of a gamma-ray irradiation plant—shanghai irradiation center

    Fugen, Chen; Xiangrong, Xue; Zewu, Yao

    Shanghai Irradiation Center, situated in western suburb of Shanghai, was completed in March, 1986. The intensity of Co 60 is 177 KCuries at present, and untimate loading will be 500 K Curies. The Center is designed mainly for food radiation preservation and sterilization of medical devices and tools. Its processing ability is 10 T/hr for potatoes.

  10. The design of a gamma-ray irradiation plant - Shanghai Irradiation Center

    Shanghai Irradiation Center, situated in western suburb of Shanghai, was completed in March, 1986. The intensity of Co60 is 177 K Curies at present, and ultimate loading will be 500 K Curies. The Center is designed mainly for food radiation preservation and sterilization of medical devices and tools. Its processing ability is 10 T/hr for potatoes. (author)

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

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

    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

  13. Preliminary research on death pattern in PC12 cell after high-dose of gamma-ray irradiation

    Objective: To investigate the death pattern of pheochromocyoma cell line (PC12 cell) irradiated with ionizing radiation and to search for a model of radiation-induced neuron injury in vitro. Methods: PC12 cell was irradiated with different doses of 60Co γ-rays. The effect of radiation on cell cycle, development, differentiation and death rate were detected by flow cytometry, light microscope, and transmission electron microscope (TEM). Results: Irradiated PC12 cell showed cell cycle retardation and differentiation, but some cells died due to swelling. Apoptosis was observed in few cells. TEM examination indicated that mitochondrion and endoplasmic reticulum were dilated markedly, chromatin was concentrated and scattered near karyotheca or around the nucleolus, which characterized oncosis. Conclusions: PC12 cell died through oncosis after gamma-ray irradiation of high-dose, and can be used as a radiation-induced neuron injury model. (authors)

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

    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)

  15. Two CdZnTe detector-equipped gamma-ray spectrometers for attribute measurements on irradiated nuclear fuel

    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 INEEL's Interim Fuel Storage Facility (IFSF) Both units have been operationally tested at the INEEL. (author)

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

    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 INEEL's Interim Fuel Storage Facility (IFSF). Both units have been operationally tested at the INEEL

  17. Prompt gamma ray measurement in the KUR irradiation room by Cd-Zn-Te semiconductor detector for PG-SPECT

    Prompt gamma-rays from 10B(n,αγ)7Li reaction yielded in polyethylene plate containing 30 wt% 10B and/or 50 ppm 10B water phantom were measured in the medical irradiation room at the KUR-HWNIF, by Cd-Zn-Te semiconductor detector with tungsten collimator which has a hole of 3 mm diameter and 8 cm and/or 14 cm length. An application possibility of Cd-Zn-Te semiconductor detector to PG-SPECT was examined experimentally for BNCT. (author)

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

    Pejović Momčilo 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.

  19. Utilization of gamma-ray irradiation for hydrogen production from water

    The present work is devoted to the effective use of gamma-ray from radioactive waste for hydrogen production from water. Radioactivity such as gamma-radiation is a long-term residual energy of nuclear reactions in which most of the energy is released spontaneously. Its high penetration power and low energy density, unfortunately, make the effective use of gamma-radiation from residues of the fuel recycling process very difficult. For the production of hydrogen by gamma-ray radiolysis of water, effective conversion of gamma-ray into the low-energy electrons and photons between a few eV and several tens of eV, i.e., appreciable increase in the energy deposition in water, was essential. This is because water molecule is inert towards gamma-ray radiation due to extremely low cross-sections. We have proposed a technique using special metal structures to increase the amount of the low-energy electrons ejected into water. In order to investigate the optimum metal structure, we have studied the mechanisms of generating lower-energy electrons and photons in water containing metals of various geometrical arrangements, by simulating the electron-photon transport processes in metal and water using the Monte-Carlo N-Particle (MCNP) code, We then demonstrated that the deposition energy to water can increase by carefully controlling the thickness of a metal component and its proximity with the adjacent component. Experimental work then showed that the optimal structure actually leads to enhanced hydrogen evolution from water.

  20. NPK, protein content and yield of broccoli as affected by gamma rays seeds irradiation and phosphorus fertilizer rates

    Two field experiments were carried out during 1999/2000 and 2000/2001 winter growing seasons at the experimental farm of Nuclear Research Center, Atomic Energy Authority, Inshas, Egypt. The experiments were conducted to study the effect of pre sowing-seeds irradiation with different doses of gamma rays (0, 2, 3 and 4 Gy) and different phosphorus fertilizer application rates, 0, 30, 60 and 90 k P2O5 /fed) on NPK content of leaves and spear, and protein content in spears at maturity, spear diameter, main spear fresh and dry weight per plant, total spear fresh weight per plant and total spear yield. In general, exposing broccoli seeds to different gamma ray doses up to 4 Gy prior to sowing increased the above mentioned parameters with different magnitudes comparing with the non-irradiated control plants. The highest percentage of increase was obtained by exposing broccoli seeds to 3 Gy. There were non-significant differences between 3 and 4 Gy treatments during the two growing seasons. With respect to the effect of phosphorus fertilizer application rates on the studied parameters, increasing phosphorus application rates up to 90 kg P2O5/fed increased the above mentioned parameters. The highest percentage of increase was obtained by applying 90 kg P2O5/fed. The interaction, gamma ray and P level showed phosphorus there were significant differences in main spear fresh and dry weight per plant, total spear yield and spear diameter in first season. The highest value was obtained by 3 Gy and 90 kg P2O5/fed. Also there were significant effects on NPK content in broccoli leaves at 90 days after transplanting (DAT) except P in second season and nonsignificant values of broccoli spear at harvest except N, K in first season. The highest protein content of broccoli spears at harvest was obtained with 2 Gy and 30 kg P25/fed

  1. Wavelet analysis of scintillation discharge current on DC tracking resistance of gamma-ray irradiated polyethylene and polycarbonate

    The use of organic insulating materials in environments such as space and nuclear power stations is spreading rapidly. There is increasing concern about the reliability of electrical insulation in these environments due to radiation effects on the surface characteristics of polymeric materials. Irradiation effects on tracking resistance should be investigated due to the increasing usage of organic materials in radiation-prone environments. This paper presents a study on the DC tracking resistance of gamma-ray irradiated polyethylene and polycarbonate materials by use of the International Electrotechnical Commission (IEC) Publication (Publ.) 112 method. Polyethylene and polycarbonate materials as the test samples were irradiated in air up to 1 x 105 Gy and 1 x 106 Gy with dosage rates of 104 Gy/h using a 60Co gamma source. The total radiation effects on erosion depth, weight loss, contact angle and scintillation discharge energy levels were studied. A gaussian wavelet analysis was applied to show these scintillation discharge energy levels. (author)

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

    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; Lugão, 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.

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

    Dumée, 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 γ-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 γ-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 γ-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 γ-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 γ-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 γ-ray reduction process. A mechanism correlating the interaction between hydrogen radicals formed upon

  4. 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

    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.

  5. Development of high yielding mutants of Brassica campestris L. cv. Toria selection through gamma rays irradiation

    Homogeneous seeds of Brassica campestris L. cv. Toria selection were treated with different doses of gamma rays (750, 1000 and 1250 Gy) to induce genetic variability for the selection of new genotypes with improved agronomic traits. After passing through different stages of selection, two promising mutants were selected for further studies. Two selected mutants along with 5 other entries including parent variety were evaluated for yield and yield components in yield trials for two consecutive years. The mutant TS96-752 was significantly (P less than or equal to 0.05) superior to all other entries in grain yield but at par with FSD 86028-3

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

    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

  7. Investigation of photoneutron and capture gamma-ray production in Pb and W under irradiation from 16N decay radiation

    Highlights: • MCNP used to investigate (γ,n) and (n,γ) in Pb and W due to interaction with 16N decay γ-rays and β. • Evidence of photoneutrons and capture gamma rays observed. • Bremsstrahlung from 16N beta spectrum insufficient to generate photoneutrons. - Abstract: Lead and tungsten are potential alternative materials for shielding reactor ex-core components with high 16N activity when available space limits application of concrete. Since the two materials are vulnerable to photonuclear reactions, the nature and intensity of the secondary radiation resulting from (γ,n) and (n,γ) reactions when 16N decay radiation interact with these materials need to be well known for effective shielding design. In this study the MCNP code was used to calculate the photoneutron and capture gamma-ray spectra in the two materials when irradiated by 16N decay radiation. It was observed that some of the photoneutrons generated in the two materials lie in the low-energy range which is considered optimum for (n,γ) reactions. Lead is more transparent to the photoneutrons when compared to tungsten. The calculations also revealed that the bremsstrahlung generated by the beta spectrum was not sufficient to trigger any additional photoneutrons. Both energetic and less energetic capture gamma-rays are observed when photoneutrons interact with nuclei of the two materials. Depending on the strength of the 16N source term, the secondary radiation could affect the effectiveness of the shield and need to be considered during design

  8. 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

    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

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

    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

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

    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.)

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

    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

  12. Investigation of photoneutron and capture gamma-ray production in Pb and W under irradiation from 16N decay radiation

    Kebwaro, Jeremiah Monari; Zhao, Yaolin; He, Chaohui

    2015-09-01

    Lead and tungsten are potential alternative materials for shielding reactor ex-core components with high 16N activity when available space limits application of concrete. Since the two materials are vulnerable to photonuclear reactions, the nature and intensity of the secondary radiation resulting from (γ,n) and (n,γ) reactions when 16N decay radiation interact with these materials need to be well known for effective shielding design. In this study the MCNP code was used to calculate the photoneutron and capture gamma-ray spectra in the two materials when irradiated by 16N decay radiation. It was observed that some of the photoneutrons generated in the two materials lie in the low-energy range which is considered optimum for (n,γ) reactions. Lead is more transparent to the photoneutrons when compared to tungsten. The calculations also revealed that the bremsstrahlung generated by the beta spectrum was not sufficient to trigger any additional photoneutrons. Both energetic and less energetic capture gamma-rays are observed when photoneutrons interact with nuclei of the two materials. Depending on the strength of the 16N source term, the secondary radiation could affect the effectiveness of the shield and need to be considered during design.

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

    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

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

    Kang, Kwon Kyoo; Jung, Yu Jin [Hankyong National University, Anseong (Korea, Republic of)

    2010-09-15

    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.

  15. Characteristic evaluation of papain irradiated with {sup 60}Co {gamma}-rays for the purpose of sterilization

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio [Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology

    1998-09-01

    To establish irradiation sterilization method for hybrid biomedical materials containing bioactive molecules together with artificial polymers, we employed dry powder and aqueous solution of papain as a model and examined radiation tolerance with {sup 60}Co {gamma}-rays. The dry powder and frozen aqueous solution showed significant resistance after 30-kGy irradiation, indicating that commercial irradiation sterilization method for disposable medical supplies was applicable. Unfrozen aqueous solutions (10mg/ml), in contrast, showed significant drop of enzymatic activity within the early period of irradiation (ca. 0.5kGy) but 40% of the activity was recovered at ca. 3-kGy before total inactivation at 15kGy. Taking various conditions including dose rate, concentration of enzyme, oxygen and nitrogen bubbling into irradiation inactivation experiments, we demonstrated that inactivation of papain could be controlled under anoxic condition, such as nitrogen bubbling, increasing sample volume at high dose rates and high concentration of enzyme where dissolved oxygen was consumed rapidly. It is suggested that radiation inactivation of papain in the aqueous solution was occurred through reversible oxidation of the sulfhydryl group at the active site by free radicals derived from radiolysis of water and dissolved oxygen. (author)

  16. New method for the estimation of the mutation rate in acute and chronic gamma-ray irradiation of growing plants

    In the case of irradiation of seeds of self-pollinated and disomic plant materials, the frequency of mutated plants appearing in the M2 generation divided by the Mendelian ratio is an index, as proposed by Gaul (1960), that enables the direct estimation of the mutation rate, representing the ratio of the number of mutated cells to the number of survived cells after treatment of mutagen. In the case of chronic irradiation of growing plants throughout the entire life cycle from germination to maturity, on the other hand, the mutations induced at the stage preceding the differentiation of the male and female organs appear at the M2 generation, the but mutations induced after this critical time are observed in the M2 plants in the heterozygous condition and are detected only at the M3 generation. Therefore, the mutation rate can not be correctly estimated only on the basis of the frequency of mutants either in the M2 or M3 generation. A new method for the estimation of the mutation rate by combining the data of the frequency of mutants and the M2 and M3 generation, which is comparable to Gaul's method for seed irradiation, is proposed. Application of this method to the data of acute and chronic gamma-ray irradiation of growing barley revealed that a much higher mutation rate was observed after irradiation at a higher daily exposure rate, when the plants were treated with the same accumulated dose

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

    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)

  18. 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

    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)

  19. 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

    Qin, Jianguo; Lai, Caifeng; 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 g...

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

    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.)

  1. Formation and conversion of defect centers in low water peak single mode optical fiber induced by gamma rays irradiation

    The formation and conversion processes of defect centers in low water peak single mode optical (LWPSM) fiber irradiated with gamma rays were investigated at room temperature using electron spin resonance. Germanium electron center (GEC) and self-trapped hole center (STH) occur when the fibers are irradiated with 1 and 5 kGy cumulative doses, respectively. With the increase in irradiation doses, the GEC defect centers disappear, and new defect centers such as E' centers (Si and Ge) and nonbridge oxygen hole centers (NBOHCs) generate. The generation of GEC and STH is attributed to the electron transfer, which is completely balanced. This is the main reason that radiation-induced attenuation (RIA) of the LWPSM fiber is only 10 dB/km at communication window. The new defect centers come from the conversion of GEC and STH to E' centers and NBOHC, and the conversion processes cause bond cleavage, which is the root cause that the RIA of the LWPSM fiber significantly increases up to 180 dB/km at working window. Furthermore, the concentration of new defect centers is saturated easily even by increasing cumulative doses.

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

    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)

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

    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 γ-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 γ 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 γ-rays decreased the surface acid density and consequently the activity of the irradiated sample towards acid catalyzed reactions decreased. (author)

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

    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

  5. Gamma-ray-enhanced reactivation of irradiated adenovirus in Xeroderma pigmentosum and Cockayne syndrome fibroblasts

    A γ-ray-enhanced reactivation (γRER) of uv-irradiated as well as of γ-irradiated human adenovirus type 2 (Ad 2) was detected following infection of normal, Xeroderma pigmentosum (XP), and Cockayne syndrome (CS) fibroblasts that had been preirradiated with γ rays. Gamma-irradiated or nonirradiated fibroblasts were infected with either nonirradiated or irradiated Ad 2, and 48 hr after infection cells were examined for the presence of viral structural antigens (Vag) using immunofluorescent staining. Results obtained using seven different normal fibroblast strains showed that irradiation of host monolayers with 1 krad immediately prior to infection resulted in a γRER factor +-SE of 4.5 +- 1.6 for uv-irradiated virus and 4.3 +- 1.3 for γ-irradiated virus. CS fibroblasts, as well as excision repair-deficient XP fibroblasts from complementation groups A and D, were all found to be capable of expressing γRER of irradiated Ad 2. XP variant cells expressed lower levels of γRER compared to most normal strains, suggesting a possible role for cellular postreplication repair in the mechanism responsible for ER in human cells. An excision-deficient XP fibroblast strain belonging to complementation group A, but derived from a patient afflicted with the severe De Sanctis-Cacchione form of XP, although proficient in γRER of γ-irradiated Ad 2, yielded barely detectable levels of γRER for uv-irradiated Ad 2

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

    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

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

    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)

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

    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)

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

    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.

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

    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

  11. Frequency dependent gamma-ray irradiation response of Sm2O3 MOS capacitors

    The frequency dependent irradiation influences on Sm2O3 MOS capacitors have been investigated and possible use of Sm2O3 in MOS-based radiation sensor was discussed in this study. To examine their gamma irradiation response over a range of doses, the fabricated MOS capacitors were irradiated up to 30 grays. Capacitance–Voltage (C–V) measurements were recorded for various doses and the influences of irradiation were determined from the mid-gap and flat-band voltage shifts. In addition, the degradations of irradiation have been studied by impedance based leakage current–voltage (J–V) characteristics. The results demonstrate that J–V characteristics have not been significantly change by irradiation and implying that the excited traps have a minor effect on current for given dose ranges. However, the frequency of applied voltage during the C–V measurements affects the irradiation response of devices, significantly. The variations on the electrical characteristics may be attributed to the different time dependency of acceptor and donor-like interface states. In spite of the variations on the device characteristics, low frequency measurements indicate that Sm2O3 is a potential candidate to be used as a dielectric layer in MOS based irradiation sensors

  12. Low temperature gamma-ray irradiation effects of polymer materials on mechanical property

    A low temperature γ-ray irradiation equipment was constructed for the evaluation of the radiation resistance of polymer materials used in low temperature environment. The change of mechanical property by irradiation at 77 K was studied for glass fiber reinforced plastic (GFRP), poly(methyl methacylate) (PMMA) and poly(tetra fluoroethylene)(PTFE), and compared with that by irradiation at room temperature. The decrease in flexural strength or in elongation at break showed a big difference between 77 K and room temperature irradiation. The ratio of dose at half strength or half elongation by 77 K and room temperature irradiation was 25 for GFRP, 17 for PMMA and 5 for PTFE. (author)

  13. A new mutant gene su-1 in corn obtained by irradiation with low doses of gamma rays

    This paper provides a description of a sugar corn mutant obtained by irradiation of wetted kernels of Romanesc de Studina variety with low doses of gamma rays (300 R). This mutant influences the structure of the endosperm similarly to the su-1 genes developed spontaneously which resulted in the corn variety Zea mays saccharata thousands of years ago. Although the mutant is a multiple allele of the su-1 locus in chromosome IV it differs widely from the spontaneous mutant. The length of the ears is much reduced, varying between 4 and 6 cm, with numbers of kernels per ear varying between 45 and 72. Attempts to improve the cob size and the number of kernels by breeding and propagation in an insulated area led to no result. Crossing the mutants with the sugar hybrid Delicious resulted in sugar type progeny which confirms the common position of the mutant gene induced by irradiation and the spontaneous su-1 gene. The progenies of sugar mutant x Delicious are 38-43 % lower in cob vigor and 36-46% lower in kernel number. (author). 2 figs, 2 tab., 16 refs

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

    Effects of γ-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 γ-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 γ-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

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

    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)

  16. The influence of irradiation of gamma-rays on the pulping and paper making, (3)

    Dissolving pulp (DP) containing no lignin and cold soda pulp containing much amount of lignin were used for the study of the influence of gamma irradiation. Experiments were made in the presence of air, water, methanol, acetic anhydride, acetic anhydride + methanol, dioxane, dimethyl sulfoxide and 1% NaOH solution. Irradiation was made for 100 hours at 20 - 21 deg. C; total irradiation dose was 1.47 x 107 R. (1) In case of dimethyl sulfoxide, and especially in case of 1% NaOH solution, the yield decreased by irradiation, with cold soda pulp particularly. (2) In case of the pulp immersed in water, the brightness of pulp was not improved by irradiation, but in methanol, it was remarkably improved. Since the improvement was observed in both DP and cold soda pulps, it is caused by the action of oxidizing bleach with small amount of oxygen in the air remaining in the material, instead of the change in the quality of lignin. (3) By infrared analysis, methanol did not react with the lignin in cold soda pulp even under irradiation. (4) The acetylation was accelerated by irradiation. (J.P.N.)

  17. Effect of pH on paste properties of irradiated corn starch by gamma-rays

    The degradation of starch by γ-irradiation and the effect of pH on gelatinization of starch after irradiation were investigated. Paste viscosities were markedly affected by pH on gelatinization and a decrease in the viscosity of irradiated starch was stimulated by increasing pH. On the other hand, the solubility of irradiated starch increased significantly at the high pH. The granule structure of irradiated starch easily disintegrated at alkaline pH. Remarkable dissolution from the surface of the irradiated starch granules was observed after heating at high pH only a filamentous network frame remained, but the unirradiated one collapsed and folded. It was seen that alkali treatment after irradiation reduces the required dose to obtain low viscosity starch. The required dose to produce a low viscosity starch, for example Ajinomoto Essan Sizer 600 grade, was ca. 3 Mrad at pH 11.0 and ca. 5 Mrad at pH 7.0, whereas it was ca. 7 Mrad without pH adjustment. (author)

  18. Effect of cobalt 60 gamma-ray irradiation on the hatching process of chicken eggs

    An experiment on fertilized chicken eggs was carried out to determine the effects of 60Co irradiation on the embryos, their fatality, and growth impairment or deformity, in particular. The experimental groups, consisting of 10 eggs each, recieved a 60Co irradiation of 50 to 2,000 rads on any one day between day 0 and day 20 of incubation. The larger the irradiation dose, the greater was the number of dead embryos. The fatality was higher in the groups receiving irradiation in the earlier stage (1st week). The resultant death was a chronic one. The irradiation also caused body weight decrease and growth impairment. A decrease in the brain and liver weights was noted, suggesting insufficiency in these organs. Deformity occurred in 4%, most of which involved impairments of skeletal growth, of the bones of the extremities and the bill, in particular. Administration of the SH amino acid, cysteine tended to alleviate the adverse effects of the 60Co irradiation. These results for fertilized chicken eggs suggest the possibility of abortion and the occurrence of deformities in human fetuses if they should be subjected to 60Co irradiation. (author)

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

    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)

  20. H2 production through oxide irradiation: Comparison of gamma rays and vacuum ultraviolet excitation

    The production of molecular hydrogen by gamma radiolysis and vacuum ultra violet photolysis of dried and hydrated nano-porous titania and zirconia nanoparticles has been studied. The nanoparticles were prepared as free standing films using a surface sol-gel process on cellulose. A significant hydrogen production was observed for both TiO2 and ZrO2 in vacuum ultra violet or gamma irradiation. This production could be optimized by controlling the amount of water and by introducing hydroxyl radical scavengers in the irradiated systems. The mechanism underlying hydrogen production seems qualitatively different in gamma and in vacuum ultra violet (VUV) irradiation. (authors)

  1. Formation of color centers in CdF/sub 2/ crystals irradiated by gamma rays

    Kaipov, B.; Tavshunskii, G.A.; Gapparov, N.

    1975-01-01

    After irradiation in liquid nitrogen, an ultraviolet absorption band in the region of 350 nm was induced in all samples. This band is maintained during annealing of thermoemission peaks below 170/sup 0/K. On annealing above this temperature the absorption band at 350 nm vanished, and the EPR signal with g = 2.014 induced by the gamma irradiation at 77/sup 0/K vanished at the same time. This behavior is attributed to the formation of localized holes by the gamma irradiation. (SJR)

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

    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.)

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

    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.

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

    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

  5. Photoluminescence spectra of thin films containing CdSe/ZnS quantum dots irradiated by 532-nm laser radiation and gamma-rays

    Sharma, Suresh C. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)], E-mail: sharma@uta.edu; Murphree, Jay; Chakraborty, Tonmoy [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2008-11-15

    We have investigated temporal behavior of the photoluminescence (PL) spectra of thin films containing CdSe/ZnS quantum dots irradiated by 532 nm laser radiation and gamma-rays. Under {approx}100 W/cm{sup 2} laser radiation, the PL intensity (I{sub PL}) increases with irradiation time upto about 500 s and thereafter declines linearly. The wavelength of the PL emission ({lambda}{sub peak}) exhibits a blue-shift with exposure time. Upon simultaneous irradiation by 100 W/cm{sup 2} 532-nm laser, as well as 0.57 and 1.06 MeV gamma-rays, the temporal behaviors of both I{sub PL} and {lambda}{sub peak} are significantly different; I{sub PL} increases to a saturation level, and the magnitude of the blue-shift in {lambda}{sub peak} is reduced. We discuss possible mechanisms underlying these results.

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

    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.

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

    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

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

    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)

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

    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)

  10. Gamma-ray irradiation effect on the absorption and luminescence spectra of Nd:GGG and Nd:GSGG laser crystals

    Sun Dunlu [Crystal Lab, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shushanhu Road 350, PO Box 1125, Hefei, Anhui 230031 (China); Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193 (Portugal)], E-mail: dlsun@aiofm.ac.cn; Luo Jianqiao; Zhang Qingli [Crystal Lab, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shushanhu Road 350, PO Box 1125, Hefei, Anhui 230031 (China); Xiao Jingzhong [Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193 (Portugal); Xu Jiayue [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Jiang Haihe; Yin Shaotang [Crystal Lab, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shushanhu Road 350, PO Box 1125, Hefei, Anhui 230031 (China)

    2008-12-15

    Laser crystals Nd{sup 3+}:Gd{sub 3}Ga{sub 5}O{sub 12} (Nd:GGG) and Nd{sup 3+}:Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} (Nd:GSGG) were grown by Czochralski method. The influence of gamma-ray irradiation on their absorption and luminescence spectra has been investigated. Two additional absorption (AA) bands induced by gamma-ray irradiation appear in the spectra of Nd:GGG crystal while only a very weak AA band appears for the Nd:GSGG crystal. This indicated that Nd:GSGG crystal has stronger ability to resist the color center formation by irradiation. The intensity of the excitation and emission spectra of Nd:GGG crystal decrease after the irradiation of 100 Mrad gamma-ray. In contrast, a luminescence strengthening effect was observed in Nd:GSGG crystal after exposure to the same irradiation dose. The results showed that the Nd:GSGG crystal is a promising candidate used under radiation environments such as in outer space.

  11. Gamma-ray irradiation effect on the absorption and luminescence spectra of Nd:GGG and Nd:GSGG laser crystals

    Laser crystals Nd3+:Gd3Ga5O12 (Nd:GGG) and Nd3+:Gd3Sc2Ga3O12 (Nd:GSGG) were grown by Czochralski method. The influence of gamma-ray irradiation on their absorption and luminescence spectra has been investigated. Two additional absorption (AA) bands induced by gamma-ray irradiation appear in the spectra of Nd:GGG crystal while only a very weak AA band appears for the Nd:GSGG crystal. This indicated that Nd:GSGG crystal has stronger ability to resist the color center formation by irradiation. The intensity of the excitation and emission spectra of Nd:GGG crystal decrease after the irradiation of 100 Mrad gamma-ray. In contrast, a luminescence strengthening effect was observed in Nd:GSGG crystal after exposure to the same irradiation dose. The results showed that the Nd:GSGG crystal is a promising candidate used under radiation environments such as in outer space

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

    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

  13. Thermal characterization of the HDPE/LDPE blend (10/90) irradiated using gamma-rays

    Puig, C.C., E-mail: cpuig@usb.v [Universidad Simon Bolivar, Departamento de Ciencia de los Materiales, Grupo de Polimeros USB, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Albano, C., E-mail: calbano@ivic.v [Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Quimica, Laboratorio de Polimeros, Apdo. 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of); Universidad Central de Venezuela, Facultad de Ingenieria, Escuela de Ingenieria Quimica, Laboratorio de Polimeros, Caracas (Venezuela, Bolivarian Republic of); Laredo, E. [Universidad Simon Bolivar, Departamento de Fisica, Grupo de Fisica de Materiales Amorfos y Cristalinos, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Quero, E. [Universidad Simon Bolivar, Departamento de Ciencia de los Materiales, Grupo de Polimeros USB, Apdo. 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); Karam, A. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Centro de Quimica, Laboratorio de Polimeros, Apdo. 21827, Caracas 1020-A (Venezuela, Bolivarian Republic of)

    2010-05-01

    Gamma irradiation effect over the properties of slow cooled and fast cooled HDPE/LDPE 10/90 blend was studied. The blend and the neat polyethylenes were irradiated at room temperature in the presence of air using the following doses (4.8 kGy/h): 0, 50, 150, 400 and 1000 kGy. Differential scanning calorimetry (DSC) experiments were carried out using the following heating rates: 5, 10 and 20 deg. C/min. DSC results for the slow and fast cooled blend showed traces with three melting peaks and with increasing irradiation dose two melting peaks were obtained, i.e. the high melting peak shifts toward lower temperatures to merge with the intermediate melting peak into one endotherm. No changes in crystal structure by X-ray diffraction were found as a result of samples irradiation. Radiation crosslinking prevents crystal rearrangements during heating in the DSC. Gel content and melt flow index (MFI) measurements showed that radiation induced a high degree of crosslinking for all samples; gel content values were above 50% and a drop of more than 90% in the MFI was found. Irradiation of slow cooled samples resulted in larger values of gel content and lower MFI values than for fast cooled samples, mainly because of the higher degree of crosslinking for the former.

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

    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

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

    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)

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

    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 γ-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 α- and β-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. (Author)

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

    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)

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

    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)

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

    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)

  20. Irradiation effect of Co-60 gamma rays in YBCO thick films

    Galvanomagnetic properties of YBa2Cu3O7-δ thick films under the action of 60Co γ-rays up to an exposure of 450 kGy are reported. The variation of physical parameters such as resistivity in the normal state, critical temperature and critical current density, as well as the increase of pinning energies with irradiation, suggests that these property changes are dominated by irradiated-induced randomly distributed oxygen defects. The three-dimensional collective pinning theory is used along with some approximations to estimate the pinning energies and critical current density. A comparison of the experimental data with the theoretical predictions demonstrates the importance of irradiation-induced oxygen defects as effective pinning centres. (author)

  1. Growth evaluation of avocado selections irradiated with gamma rays Co 60

    The vegetative growth of two years old avocado selections treated with 2 krads of gamma irradiation compared with not irradiated trees (control) was evaluated determining tree height, trunk diameter, shoots length, inter nodes number and growth habit, finding that the irradiated selections Colinmex, 175 PLS and 39 PMe have modified their growth habits towards more horizontal tendency, minor shoots length and more inter nodes. Also in this article is presented an evaluation of the scion development of 10 avocado selections treated with 0,1,3,5 and 7 krad, finding variation in the sensibility of the materials after eight months grafted, Colin V-101, 131 PLS and 175 PLS exhibited only 12 % survival meanwhile Colin V-33 and Colinmex had 70 % survival, but only in the 1 krad dosage, because at higher doses the graft wood died. (Author)

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

    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)

  3. A comparative study on experimental and theoretical ESR spectra of lactic acid polymers irradiated by gamma rays

    Homo polymers of L-Lactic acid (LLA) and D,L-Lactic acid (DLLA), being biocompatible and absorbable in body iluids have recently found wide applications in the preparation of surgical sutures, controlled drug delivery systems, burn wound coverings etc. For sometime these polymers have also been prepared in the form of plates and screws for mandibular fracture fixation, tissue implants. Their chemical sensitivities against relatively high temperatures and hydrolysis with water make them unsuitable for conventional sterilization techniques like hot water vapor and ethylene oxide. Sterilization of the devices made of these polymers is therefore possible by gamma ray irradiation. This has initiated a number of research works in order to better understand the effects of ionizing radiation on this polymer. The aim of this study is to determine the possible radical types, their location on macromolecular structure and the reasons for peak shifts in the experimental and theoretical ESR spectra. Polymer samples were irradiated in air and in vacuum (10□□ torr) to 25 kGy sterilization dose at the dose rate 0.59 kGy/h and at room temperature by 60Co γ-irradiator. Despite being chemically the same radical type, some differences were observed in the splitting of peaks of PLLA and PDLLA samples. These differences were determined and compared by means of fitting studies. Firstly, PLLA was characterized and its g and hyperfine splitting values were found as 2.0032±0.0002 and 20.37±0.2. In the characterization study of PDLLA, it was found that one of the nearest two radicals was on the upper and the other one was on the lower plane of PDLLA chain. (author)

  4. Irradiation effect on enzymatic activity of papain with {sup 60}Co-{gamma} rays

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio [Osaka Prefecture Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology

    1998-12-31

    An investigation was made on the durability of enzyme activity against {sup 60}Co-{gamma} irradiation at a dose up to 55 kGy/h using dry powder and aqueous solution of papain preparations on the market. Hybrid materials including bioactive molecules combined with biocompatible synthetic polymers are expected to have biocompatible properties and also biomimetic functions as a component of artificial organs for human body. The activity of papain in an aqueous solution was rapidly decreased at the early stage of irradiation through oxidation of SH group at its active site with active oxygen produced by the irradiation and then, partially recovered since SH group was reproduced in an anoxic state after O{sub 2} consumption in the solution irradiated at a high dose. A usual radiation method for sterilization was found applicable to decontamination of dry and frozen preparations of papain. When suitable conditions for radiation were chosen and N{sub 2} gas was purged to suppress the formation of free radicals, it was possible to keep the enzyme activity at more than 50% of the initial activity after radiation at 30 kGy. (M.N.)

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

    Effects of γ-irradiation and deformation temperatures on the hardening behavior of Al-5356 alloy have been investigated by means of stress–strain 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 1.5×10−3 s−1. The effect of γ-irradiation on the work-hardening parameters (WHP): yield stress σy, fracture stress σf, total strain εT and work-hardening coefficient χp of the given alloy was studied at the applied deformation temperature range. The obtained results showed that γ-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

  6. Isothermal Crystallization Kinetics of HDPE/HA Compounds Irradiated with Sterilization Doses of Gamma Rays

    The objective of this work was to study the isothermal crystallization of High Density Polyethylene/Hydroxyapatite nanocomposites, with 2 and 5 ppc of HA, irradiated with 25 kGy (sterilization dose) of γ-Ray from a 60Co source, at a rate of 4.8 kGy/h in air and at room temperature. The selected crystallization temperatures were 118, 117, 116 and 115 degree. The crystallization kinetics was analyzed using the Avrami's model whose parameters were optimized using a non-linear regression technique. Regression results show that the Avrami exponent varies between 1.8 and 1.5, meaning that the spherulitic growth is mainly two dimensional. Values for specific crystallization constant 'k' were found to be higher for HDPE/HA compounds than for pure HDPE, clearly indicating the presence of an HA nucleation effect. It was also observed that values for the specific crystallization constant 'k' decreases with increasing temperatures, being this effect more noticeable for HDPE/HA compounds than for pure HDPE. Regarding to irradiated samples, their 'k' values were found to be lower than those for non irradiated samples, the difference getting more significant with decreasing crystallization temperature. Simulation of experimental data with the Avrami's model show a clear influence of the crystallization temperature, the HA content in the sample and the amount of applied radiation. It was also observed that the Avrami model correlates satisfactorily experimental data for not irradiated samples of pure HDPE and HDPE/HA compounds at the highest crystallization (Tc). However, as the crystallization temperature decreases, the values simulated with the Avrami model increasingly deviate from experimental data, specifically at the highest values of the relative crystallinity. This effect is even stronger on irradiated samples of HDPE and HDPE/HA compounds

  7. Influence of Gamma-Ray Irradiation on Absorption and Fluorescent Spectra of Nd:YAG and Yb:YAG Laser Crystals

    We investigate the influence of gamma-ray irradiation on the absorption and fluorescent spectra of Nd3+:Y3A15O12 (Nd:YAG) and Yb3+:Y3A15O12 (Yb:YAG) crystals grown by the Czochralski method. Two additional absorption (AA) bands induced by gamma-ray irradiation appear at 255nm and 340 nm. The former is contributed due to Fe3+ impurity, the latter is due to Fe2+ ions and F-type colour centres. The intensity of the excitation and emission spectra as well as the fluorescent lifetime of Nd:YAG crystal decrease after the irradiation of 100Mrad gamma-ray In contrast, the same dose irradiation does not impair the fluorescent properties of Yb:YAG crystal. These results indicate that Yb:YAG crystal possesses the advantage over Nd:YAG crystal that has better reliability for applications in harsh radiant environment. (fundamental areas of phenomenology (including applications))

  8. Detection of corn starch irradiated with low doses of gamma rays. Pt. 4

    Hydrogen peroxide and malonaldehyde, which are both radiolysis products of stark, appear not to react with each other when mixed into unirradiated starch. Amino acids, when mixed into unirradiated starch containing malonaldehyde, cause the malonaldehyde to disappear at a measurable rate. This suggests that the malonaldehyde reacts with amino acids rather than with the peroxide, and that this is a more likely path for the disappearance of manlonaldehyde from irradiated starch. (orig.)

  9. Thermoluminescence of CsCl:Ce crystals irradiated with gamma rays

    UV-visible absorption spectrum of CsCl:Ce crystal shows two sharp bands at 267nm and 205nm. Upon γ-irradiation the characteristic F and V bands form, which are similar to those observed in pure CsCl. Three glow peaks at 363 K, 378 K and 408 K have been identified in the irradiated crystals. The resistance of the 408 K peak to F-bleaching, is more compared to the lower temperature peaks. The TL emission spectra show emission bands at 445nm and 388nm. The 388nm band is attributed to the emission of Ce3+ ions and the 445nm band is attributed to the emission of Eu2+ ions, which were present as unintentional impurities. These results are correlated with the photoluminescence spectra. The thermoluminescence emission of γ-irradiated CsCl:Ce crystal appears to be due to the energy transfer from the recombining F-center electron and V-center pair, to the nearby Ce3+ and Eu2+ ions in the lattice. (author). 11 refs., 5 figs

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

    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.

  11. Effect of 60Co gamma-ray irradiation on dilute aqueous solutions of surfactants

    Present work deals with the effects of gamma irradiation from 60Co γ-ray source upon aqueous solutions of three kinds of surfactants. When dilute aqueous solutions of sodium dodecyl sulfate (SDS, anionic), cethyl trimethyl ammonium chloride (CTAC, cationic), and polyoxyethylene lauryl ether (POE, non-ionic) were irradiated with γ-rays at a room temperature, the residual concentration, products, surface tension, and forming power were examined by colorimetric method, IR spectrophotometric method, gaschromatography, Ross-Miles method, and Traube's stalagmometer etc. These surfactants were decomposed by the irradiation and thus the surface tension increased and the forming power, on the contrary, decreased with dose. Radiation chemical yields (G-value) of the degradation were about 1 for the solutions of SDS and CTAC, and about 0.3 for the POE solution. From the experimental results, it was found that following chemical reactions seem to occur followed by the radiolysis of water: a) bond cleavage of ester for SDS, of CN for CTAC, and of oxyethylene for POE, b) hydrogen abstraction from the surfactants, c) production of CO bond in the presence of dissolved oxygen. (auth.)

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

    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

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

    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 γ-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)

  14. Induction of skin papillomas in the rabbit, Oryctologus cuniculus, by bites of a blood-sucking insect, Cimex lectularius, irradiated by gamma rays

    Bed bugs, Cimex lectularius, irradiated with gamma rays were allowed to suck blood from shaved areas of the skin of rabbits, Oryctolagus cuniculus, 2 times/week for 5 months and then once weekly for another 5 months. This significantly induced the formation of skin papillomas and sweat gland hyperplasia in five out of nine experimental animals. It is speculated that the saliva of the irradiated bugs was activated by gamma rays and was responsible for the induction of skin papillomas. Because bed bugs play a significant role in the transmission of virus, it is also speculated that there is a virus in the saliva of bugs; this virus may be activated by gamma radiation and causes the development of papillomas in the skin

  15. Simulation and experimental verification of prompt gamma-ray emissions during proton irradiation

    Irradiation with protons and light ions offers new possibilities for tumor therapy but has a strong need for novel imaging modalities for treatment verification. The development of new detector systems, which can provide an in vivo range assessment or dosimetry, requires an accurate knowledge of the secondary radiation field and reliable Monte Carlo simulations. This paper presents multiple measurements to characterize the prompt γ-ray emissions during proton irradiation and benchmarks the latest Geant4 code against the experimental findings. Within the scope of this work, the total photon yield for different target materials, the energy spectra as well as the γ-ray depth profile were assessed. Experiments were performed at the superconducting AGOR cyclotron at KVI-CART, University of Groningen. Properties of the γ-ray emissions were experimentally determined. The prompt γ-ray emissions were measured utilizing a conventional HPGe detector system (Clover) and quantitatively compared to simulations. With the selected physics list QGSP-BIC-HP, Geant4 strongly overestimates the photon yield in most cases, sometimes up to 50%. The shape of the spectrum and qualitative occurrence of discrete γ lines is reproduced accurately. A sliced phantom was designed to determine the depth profile of the photons. The position of the distal fall-off in the simulations agrees with the measurements, albeit the peak height is also overestimated. Hence, Geant4 simulations of prompt γ-ray emissions from irradiation with protons are currently far less reliable as compared to simulations of the electromagnetic processes. Deviations from experimental findings were observed and quantified. Although there has been a constant improvement of Geant4 in the hadronic sector, there is still a gap to close. (paper)

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

    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)

  17. Oxygen formation in gamma-ray irradiation of Fe2+ -Cu2+ solutions

    Bjergbakke, Erling; Hart, E.J.

    1971-01-01

    The mechanism of O2 formation has been studied in 60 Co γ-ray-irradiated Fe(II) + Cu(II) solutions at 0.01 N HClO4 and at 0.01, 0.08, and 0.80 N H2 SO4. In the H2 SO4 system, ${\\rm G}({\\rm O}_{2})$ rises to plateau levels near 0.02 as the ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratio increases. The plateau...

  18. Gamma-ray irradiation induce suppression of TNF-α production via up-regulation of maitogen-activated protein kinase phosphatase-1

    Complete text of publication follows. Ionizing irradiation induces DNA damage and activates a lot of signalling pathways, such as ATM and p53, due to repair the DNA damage. On the other hand, irradiation also induces activation of extracellular signal regulated protein kinase (ERK1/2) through trans-activation of EGF receptor. However, EGF-receptor-independent signalling pathways induced by irradiation are unclear. Here, we studied gamma-ray irradiation-induced signaling pathways focusing mitogen-activated kinase (MAPK), such as ERK1/2 and p38 MAPK in human keratinocyte HaCat cells, which express EGF receptor, and mouse macrophage RAW264.7 cells, which express EGF receptor at low level. These cells were irradiated by gamma-ray (0.05-2.5 Gy) from 137Cs source (0.96 Gy/min), and phosphorylated MAPKs were detected by immune blotting. Gamma-ray irradiation (0.1- 2.5Gy) induced phosphorylation of ERK1/2 in HaCat cells. However, dephosphorylation of p38 MAPK was occurred 15 min after the irradiation, indicating activation of MAPK phosphatase (MKP). On the other hand, dephosphorylation of not only p38 MAPK but also ERK1/2 were induced 15 min after irradiation (0.5 Gy) in RAW264.7 cells. At the same time point, expression of MKP-1, which dephosphorylates ERK1/2 and p38 MAPK, was significantly increased. Up-regulation of MKP-1 and dephosphorylation of p38 MAPK were also observed in irradiated mouse peritoneal macrophage. Because phosphorylation of p38 MAPK mediates pro-inflammatory cytokines, such as TNF-α , we examined the change in production of TNF-α after irradiation. Production of TNF-α was suppressed in 0.5 Gy irradiated RAW264.7 cells. In conclusion, our results suggest that gamma-ray irradiation induces up-regulation of MKP-1, leading to dephosphorylation of p38 MAPK and suppression of TNF-α production in RAW264.7cells, though ERK1/2 is activated through activation of EGF receptor in HaCat cells.

  19. Synergism of. gamma. -ray irradiation and temperature on the deterioration of flame-retardant cables, 2

    Okamoto, Shinichi (Radiation Center of Osaka Prefecture, Sakai (Japan)); Katayama, Shiro; Takeya, Chikashi; Hayakawa, Tsutomu; Iwata, Seiji

    1982-03-01

    Following our previous paper, aging tests of two flame-retardant cables, C*V and P*N, were conducted under combined environment of heat (90 and 120/sup 0/C) and radiation (2.5 x 10/sup 7/ -- 2 x 10/sup 8/..gamma..) and characteristic changes were measured in order to study synergism at reduced temperature. As a result, synergism appeared in C* (RF-XL PE) and P* (FR-EPR) after heavier dosage at elevated temperature owing to their excellent resistance to heat and radiation. On the contrary, V (PVC) showed synergism after irradiation of 2.5 x 10/sup 7/..gamma.. at 90 and 120/sup 0/C, and N(Neoprene) showed synergism after irradiation of 2.5 x 10/sup 7/..gamma.. and less at 90/sup 0/C and over. It is clear that elongation is the best index of investigating the deterioration of characteristics because of its continuous and uniform change. Also, the degradation of electrical characteristics occured in C* and P* simultaneously with or later than that of mechanical ones.

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

    The 70SnF2·30P2O5 glasses containing 25-500 ppm of fluorescein exhibit change in color from light yellow to reddish orange (absorption maximum, λ=500 nm) when heated at 240degC for 120-180 min. The fluorophosphate glasses also change the color from light yellow to reddish brown (λ=480 nm) when irradiated with 60Co γ-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 γ-ray irradiated 70SnF2·30P2O5 glasses showed a poorly resolved doublet, which was ascribed to a hole-trapped PO3F- center produced by electron scattering: PO3F2- → PO3F- + e-. (author)

  1. Trace the polymerization induced by gamma-ray irradiated silica particles

    Lee, Hoik; Ryu, Jungju; Kim, Myungwoong; Im, Seung Soon; Kim, Ick Soo; Sohn, Daewon

    2016-08-01

    A γ-ray irradiation to inorganic particles is a promising technique for preparation of organic/inorganic composites as it offers a number of advantages such as an additive-free polymerizations conducted under mild conditions, avoiding undesired damage to organic components in the composites. Herein, we demonstrated a step-wise formation mechanism of organic/inorganic nanocomposite hydrogel in detail. The γ-ray irradiation to silica particles dispersed in water generates peroxide groups on their surface, enabling surface-initiated polymerization of acrylic acid from the inorganic material. As a result, poly(acrylic acid) (PAA) covers the silica particles in the form of a core-shell at the initial stage. Then, PAA-coated silica particles associate with each other by combination of radicals at the end of chains on different particles, leading to micro-gel domains. Finally, the micro-gels are further associated with each other to form a 3D network structure. We investigated this mechanism using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Our result strongly suggests that controlling reaction time is critical to achieve specific and desirable organic/inorganic nanocomposite structure among core-shell particles, micro-gels and 3D network bulk hydrogel.

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

    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

  3. Decomposition of colored wastewater for recycling water by gamma-ray irradiation

    Utilization of advanced treated water from wastewater treatment plants for the restoration of waterway is in progress to improve the waterside environment. However, the colored wastewater containing molasses pigments, melanoidins, is not decolorized by activated sludge process, and the water can not be applied for recycling water. We have studied the radiation treatment for decolorization of wastewater discharged from baker's yeast factory. The decolorization after decomposition of colored biorefractory organic substances in wastewater, enhancement in biodegradability and effective decrease in values of COD were observed after gammaray irradiation. Although the decrease in values of COD was observed, however chromaticity was not improved after the combined treatment of wastewater by radiation together with activated sludge. The result suggests that it is necessary to find the optimum conditions for stimulation of sludge in the combined treatment. (author)

  4. Study On Effect Of Immune Stimulation Of Gamma-Ray Irradiated Chitosan On Tilapia

    Low molecular weight chitosan (LMWC) powder and oligochitosan solution were prepared by γ-irradiation method. The efficiency of the degradation process was demonstrated by gel permeation chromatography (GPC) analysis of the average molecular weight of degraded chitosan. Results showed that the molecular weights decreased with increasing doses. For LMWC molecular weight reduces from 120,000 Da to 40,000 Da when dose raises from 0 kGy to 50 kGy and oligochitosan reduces to 6100 Da at 20 kGy. Tilapia fish, which was fed with LMWC and oligochitosan 100 ppm for 45 days, was challenged with Streptococcus agalactiae bacteria to investigate immune response. The results also exhibited that oligochitosan has effect of immune response higher than LMWC. The effect of various concentrations (50 ppm, 100 ppm, 150 ppm) was investigated. Results showed that oligochitosan 100 ppm shows survival rate the highest. (author)

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

    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.

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

    Pregnant rats of Donryu strain were exposed to a whole-body 60Co γ 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 γ 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.)

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

    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 γ-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 β-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 β-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.)

  8. Effect of extremely low temperature gamma ray irradiation on polymer materials

    Polymer materials and composite materials are used in such extreme situation as the environment of nuclear fusion reactors, and such use is expected to increase hereafter. In the thermonuclear fusion reactors of magnetic confinement type, superconducting magnets are used for those of next period, and as their insulator materials, glass fiber-reinforced plastics (GFRP) are used. This GFRP is exposed to radiation at extremely low temperature, and the cumulative dose is estimated as 30 - 50 MGy. It is necessary to select or develop the material that withstands such environment, and it is demanded to acquire the reliable data. In order to study the radiation resistance at extremely low temperature of the composite materials and various polymer materials, which are used as the insulator materials for the superconducting magnets of nuclear fusion reactors, the extremely low temperature irradiation testing facility was manufactured, and the evaluation of radiation resistance has been advanced. The testing facility, the experiemtnal method and the results are reported. (K.I.)

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

    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)

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

    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

  11. Major soluble proteome changes in Deinococcus deserti over the earliest stages following gamma-ray irradiation

    Deinococcus deserti VCD115 has been isolated from Sahara surface sand. This radio-tolerant bacterium represents an experimental model of choice to understand adaptation to harsh conditions encountered in hot arid deserts. We analysed the soluble proteome dynamics in this environmentally relevant model after exposure to 3 kGy gamma radiation, a non-lethal dose that generates massive DNA damages. For this, cells were harvested at different time lapses after irradiation and their soluble proteome contents have been analysed by 2-DE and mass spectrometry. In the first stage of the time course we observed accumulation of DNA damage response protein DdrB (that shows the highest fold change ∼11), SSB, and two different RecA proteins (RecAP and RecAC). Induction of DNA repair protein PprA, DNA damage response protein DdrD and the two gyrase subunits (GyrA and GyrB) was also detected. A response regulator of the SarP family, a type II site-specific deoxyribonuclease and a putative N-acetyltransferase are three new proteins found to be induced. In a more delayed stage, we observed accumulation of several proteins related to central metabolism and protein turn-over, as well as helicase UvrD and novel forms of both gyrase subunits differing in terms of isoelectric point and molecular weight. Conclusions: Post-translational modifications of GyrA (N-terminal methionine removal and acetylation) have been evidenced and their significance discussed. We found that the Deide-02842 restriction enzyme, which is specifically found in D. deserti, is a new potential member of the radiation/desiccation response regulon, highlighting the specificities of D. deserti compared to the D. radiodurans model. (authors)

  12. Major soluble proteome changes in Deinococcus deserti over the earliest stages following gamma-ray irradiation

    Dedieu Alain

    2013-01-01

    Full Text Available Abstract Background Deinococcus deserti VCD115 has been isolated from Sahara surface sand. This radiotolerant bacterium represents an experimental model of choice to understand adaptation to harsh conditions encountered in hot arid deserts. We analysed the soluble proteome dynamics in this environmentally relevant model after exposure to 3 kGy gamma radiation, a non-lethal dose that generates massive DNA damages. For this, cells were harvested at different time lapses after irradiation and their soluble proteome contents have been analysed by 2-DE and mass spectrometry. Results In the first stage of the time course we observed accumulation of DNA damage response protein DdrB (that shows the highest fold change ~11, SSB, and two different RecA proteins (RecAP and RecAC. Induction of DNA repair protein PprA, DNA damage response protein DdrD and the two gyrase subunits (GyrA and GyrB was also detected. A response regulator of the SarP family, a type II site-specific deoxyribonuclease and a putative N-acetyltransferase are three new proteins found to be induced. In a more delayed stage, we observed accumulation of several proteins related to central metabolism and protein turn-over, as well as helicase UvrD and novel forms of both gyrase subunits differing in terms of isoelectric point and molecular weight. Conclusions Post-translational modifications of GyrA (N-terminal methionine removal and acetylation have been evidenced and their significance discussed. We found that the Deide_02842 restriction enzyme, which is specifically found in D. deserti, is a new potential member of the radiation/desiccation response regulon, highlighting the specificities of D. deserti compared to the D. radiodurans model.

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

    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

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

    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

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

    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

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

    Salah, Numan, E-mail: nsalah@kau.edu.sa [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alharbi, Najlaa D. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Sciences Faculty for Girls, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Habib, Sami S. [Department of Aeronautical Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

    2015-05-15

    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 Eu{sup 3+} 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.

  17. Gamma-ray methods

    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

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

    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)

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

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

    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)

  1. Gamma-ray astronomy

    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...

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

    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.

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

    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)

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

    Kasumi, Masakazu [Plant Biotechnology Inst., Ibaraki Agricultural Center, Iwama, Ibaraki (Japan)

    2002-05-01

    Strawberry (Fragaria x ananassa 'Nyoho') calli, derived from anthers, were irradiated with gamma -ray at dosages from 100 to 1,600 Gy (10 Gy {center_dot} hr{sup -}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)

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

    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)

  6. Thermoluminescence properties of Al{sub 2}O{sub 3}:Tb nanoparticles irradiated by gamma rays and 85 MeV C{sup 6+} ion beam

    Salah, Numan, E-mail: nsalah@kau.edu.sa [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alharbi, Najlaa D. [Sciences Faculty for Girls, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Habib, Sami S. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Lochab, S.P. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2015-11-15

    Carbon ions beam is recently recognized as an ideal cancer treatment modality, because of its excellent local tumor control. These ions have a high relative biological effectiveness resulting from high linear energy transfer (LET) and their sharp Bragg peak. However, the dose of those energetic ions needs to be measured with great precision using a proper dosimeter. Aluminum Oxide (Al{sub 2}O{sub 3}) is a highly luminescent phosphor widely used for radiation dosimetry using thermoluminesence (TL) technique. In this work nanoparticles of this material activated by different elements like Eu, Tb, Dy, Cu and Ag were evaluated for their TL response to gamma rays irradiation. Tb doped sample is found to be the most sensitive sample, which could be selected for exposure to 85 MeV C{sup 6+} ion beam in the fluence range 10{sup 9}–10{sup 13} ions/cm{sup 2}. The obtained result shows that C ion beam irradiated sample has a simple glow curve structure with a prominent glow peak at around 230 °C. This glow curve has a dosimetric peak better than those induced by gamma rays. This glow peak exhibits a linear response in the range 10{sup 9}–10{sup 11} ions/cm{sup 2}, corresponding to the equivalent absorbed doses 0.285–28.5 kGy. The absorbed doses, penetration depths and main energy loss were calculated using TRIM code based on the Monte Carlo simulation. The wide linear response of Al{sub 2}O{sub 3}:Tb nanoparticles along with the low fading makes this low cost nanomaterial a good candidate for C ion beam dosimetry. - Highlights: • Nanoparticles of Al{sub 2}O{sub 3} doped with Eu, Tb, Dy, Cu and Ag were synthesised. • They were evaluated for their TL response to gamma rays and C ion beam irradiation. • Tb doped sample is the most sensitive sample to gamma rays. • Al{sub 2}O{sub 3}:Tb was exposed to 85 MeV C{sup 6+} ion beam in the fluence range 10{sup 9}-10{sup 13} ions/cm{sup 2}. • The glow peak induced by C ions has a linear response in the range 10{sup 9

  7. Formation of fine palladium particles from palladium sulfate aqueous solution by gamma-ray irradiation as observed by electronic absorption spectroscopy and dynamic light scattering

    To find a way of probing the coagulation of metal particles formed by the irradiation of metallic ion solution without surfactant, palladium sulfate aqueous solution was irradiated with gamma rays (11.2kGy/h, 10kGy) and turbidity change of the solution after irradiation was followed by optical density at 700nm using a UV-visible spectrophotometer. The particle diameter distribution was monitored by dynamic light scattering. The results indicate that the turbidity decreased monotonously, and that there are major peaks in the distributions, one with diameters in the 400-800nm region and the other with diameters in the 1500-2500nm. The density of the particles seems to be smaller than that of bulk palladium metal. Similar experiments were carried out on palladium-silver sulfate solution. (author)

  8. Assessment of radioprotective effects of amifostine on human lymphocytes irradiated in vitro by gamma-rays using cytokinesis-blocked micronucleus assay

    A radioprotective effect of amifostine as well as its ability to modulate the level of spontaneous and gamma-rays-induced genetic changes on human peripheral blood lymphocytes has been investigated. Amifostine, known as a potent radical scavenger, has been introduced as the most effective radioprotector, yet it is not completely approved for the clinical use. However, further in vitro and clinical studies are needed to clarify its mechanisms of action. Materials and Methods: Whole blood samples from healthy donors were exposed to various doses of gamma-rays. Lymphocytes in cultures were treated with amifostine at different concentrations (2, 4 and 6 m M) in the presence or in the absence of 1 U/ml alkaline phosphatase before or after gamma-irradiation. Standard procedure for the cytokinesis-block micronucleus (CBMN) assay was used to assess the effect of amifostine on radiation induced micronucleus in bi nucleate lymphocytes. Results: Irradiated blood samples showed an increase in the total number of micronuclei (MN) significantly different from controls (p<0.05). However, pre-treatment of lymphocytes with amifostine in the presence of alkaline phosphatase, 15 minutes before irradiation, led to a significant decrease in the frequencies of MN and cells with more than one MN (p< O.05). Antifeminist, in its own, produced little or no protection. However, the addition of amifostine with alkaline phosphatase to the cell cultures 15 minutes after irradiation produced substantial radioprotection significantly different from the frequencies of MN induced by radiation alone (p< O.05). Conclusion: Results clearly indicated that gamma-rays induced MN in lymphocytes in a dose dependent manner. The highest protective effect was achieved when amifostine was phosphorylated by alkaline phosphatase and present before irradiation in the cellular environment, was indicating its radical scavenging mechanism of radioprotection. Since the administration of amifostine after irradiation

  9. Study on the effects of gamma ray irradiation on the morphological variations of Brassia verrucosa Lindl. from in vitro bud clusters

    The idea of creating sources of morphological variation of Warty Brassia (Brassia verrucosa Lindl.) was made on the basis of using in vitro bud clusters by gamma ray irradiation, aimed at selecting varieties to overcome these limitations and enhance the value of Warty Brassia. The study consists of the following contents: determining doses of gamma radiation to create variation of Warty Brassia; evaluating the effect of gamma radiation to the formation changes of the trees; isolated and selective variations to generate material source for mutation breeding. The results showed that gamma ray irradiation treatment, Co-60 source at doses 10-50 Gy of Warty Brassia from in vitro bud clusters isolated 6 different morphological variation; the variant of morphology, structure and diameter of pseudobulb were very difference comparing to control; the variant types are good growth and development in green house. In particular, there are two lines of variation, with large pseudobulb, dark green leaves and round pseudobulb, short leaves, is very promising for the development of potential mutants. The types of variation will be analyzed using molecular biology techniques to prove mutations and are going to continue selective color, flower shape in green house. (author)

  10. The effect of pre-heating and pre-irradiation with gamma rays on thermal annealing in bis [n-benzoil-n-phenyl hydroxilaminate] copper (II)

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

  11. Induction of mutations for plant height and inheritance of dwarf mutant in groundnut (Arachis hypogaea L. through gamma ray irradiation

    Anand M. Badigannavar and Suvendu Mondal

    2010-03-01

    Full Text Available Gamma ray induced mutagenesis of groundnut cultitvar TAG 24 evolved true breeding several mutantsaffecting various morphological traits. Among them, 16 mutants were dwarf and three were tall. Plant heightwas reduced by 24.5% to 41.0% in dwarf mutants and increased by 13.1 to 30.6% in tall mutants. Progeniesfrom an interesting dwarf mutant consistently segregated into dwarf, extreme dwarf and parental types. From thehybridization between mutant and its parent, it was concluded that dwarf mutation was due to monogenicincomplete dominance.

  12. Gamma-ray sources

    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.)

  13. 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

    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

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

    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.

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

    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

  16. Changes in growth and yield characters and in genetic variation of peanut (Arachis hypogaea L.) plants due to gamma ray irradiation

    Air dried seeds of two peanut cultivars Giza 4 and Giza 5 were subjected to irradiation treatments of Co60 gamma ray doses i.e. 0, 100, 150, 200, 250 Gy to study their effect on growth characters, yield components, genetic variation, heritability and genetic advance for election; during 2000 and 2001 summer seasons. Results indicated that, the 100 Gy treatment produced the highest means of most growth characters in M1 and M2 generations, however the 250 Gy treatment produced the highest means for No. of pods/plant, pod yield/plant, seed yield/plant and shelling percentage in M1 generation, but the 200 Gy treatment produced the highest means of yield components in M2 generation for the two cultivars Giza 4 Giza 5. In general, mean percentages of oil and protein were decreased by increasing gamma ray doses in M1 and M2 generations for both Giza 4 and Giza 5. The highest estimates of phenotypic and genotypic coefficient of variation, heritability and genetic advance under selection were obtained with 250 Gy dose for most growth characters and yield components as well as oil and protein percentages of the two cultivars in both M1 and M2 generations

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

    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

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

    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)

  19. Effects of gamma-ray irradiation on interface states and series-resistance characteristics of BiFeO3 MOS capacitors

    Kaya, Senol; Aktag, Aliekber; Yilmaz, Ercan

    2014-01-01

    The effects of radiation on the electrical-interface-state density (Dit) and series resistance (Rs) characteristics of BiFeO3 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. C-V and G/ω-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 C-V and G/ω-V curves. A slightly decrease in the Rs 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 Rs and Dit characteristics of BiFeO3 MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 1011 eV-1 cm-2. However, the calculated Dit values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range.

  20. Effects of gamma-ray irradiation on interface states and series-resistance characteristics of BiFeO3 MOS capacitors

    The effects of radiation on the electrical-interface-state density (Dit) and series resistance (Rs) characteristics of BiFeO3 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. C–V and G/ω–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 C–V and G/ω–V curves. A slightly decrease in the Rs 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 Rs and Dit characteristics of BiFeO3 MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 1011 eV−1 cm−2. However, the calculated Dit values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range

  1. Gamma-ray Astronomy

    Hinton, Jim

    2007-01-01

    The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

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

    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

  3. Gamma ray auto absorption correction evaluation methodology

    Neutron activation analysis (NAA) is a well established nuclear technique, suited to investigate the microstructural or elemental composition and can be applied to studies of a large variety of samples. The work with large samples involves, beside the development of large irradiation devices with well know neutron field characteristics, the knowledge of perturbing phenomena and adequate evaluation of correction factors like: neutron self shielding, extended source correction, gamma ray auto absorption. The objective of the works presented in this paper is to validate an appropriate methodology for gamma ray auto absorption correction evaluation for large inhomogeneous samples. For this purpose a benchmark experiment has been defined - a simple gamma ray transmission experiment, easy to be reproduced. The gamma ray attenuation in pottery samples has been measured and computed using MCNP5 code. The results show a good agreement between the computed and measured values, proving that the proposed methodology is able to evaluate the correction factors. (authors)

  4. Gamma-ray astronomy

    Ramaty, R.; Lingenfelter, R. E.

    1982-01-01

    Cosmic gamma rays, the physical processes responsible for their production and the astrophysical sites from which they were seen are reported. The bulk of the observed gamma ray emission is in the photon energy range from about 0.1 MeV to 1 GeV, where observations are carried out above the atmosphere. There are also, however, gamma ray observations at higher energies obtained by detecting the Cerenkov light produced by the high energy photons in the atmosphere. Gamma ray emission was observed from sources as close as the Sun and the Moon and as distant as the quasar 3C273, as well as from various other galactic and extragalactic sites. The radiation processes also range from the well understood, e.g. energetic particle interactions with matter, to the still incompletely researched, such as radiation transfer in optically thick electron positron plasmas in intense neutron star magnetic fields.

  5. Gamma ray camera

    An improved Anger-type gamma ray camera utilizes a proximity-type image intensifier tube. It has a greater capability for distinguishing between incident and scattered radiation, and greater spatial resolution capabilities

  6. Effects of glucose irradiated by high doses of 60cobalt gamma rays, and of some products of glucose radiolysis on the growth of Jerusalem Artichoke tissue and potato shoots culture in vitro

    Glucose, irradiated in dry conditions by gamma rays from 5.105 to 107 rad, and incorporated into culture medium, inhibits growth and, simultaneously, increases rhizogenesis of Jerusalem Artichoke tissue in culture. Tuberisation of potato shoots grown in vitro is delayed and partially inhibited. Some substances which result from radiolysis of sugars give the same results, but only at higher concentrations

  7. Gamma ray optics

    Jentschel, M.; Guenther, M. M.; Habs, D.; Thirolf, P. G. [Institut Laue-Langevin, F38042 Grenoble (France); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching, Germany and Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany)

    2012-07-09

    Via refractive or diffractive scattering one can shape {gamma} 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/E{sup 2}, 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/E{sup 2} 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.

  8. Application of radiochemical-and direct gamma ray spectrometry methods for the determination of the burnup of irradiated uranium oxide

    The burn-up of U3O8 (natural uranium) samples was determined by using both destructive and non-destructive methods, and comparing the results obtained. The radioisotopes 144Ce, 103Ru, 106Ru, 137Cs and 95Zr were chosen as monitors. In order to isolate the radioisotopes chosen as monitors, a separation scheme has been established in which the solvent extraction technic is used to separate cerium, cesium, and ruthenium one from the other and from uranium. The separation between zirconium and niobium and of both from the others was accomplished by means of adsorption on a silica-gel column. When the non-destructive method was used, the radioactivity of each nuclide of interest was measured in the presence of all others. For this purpose, use was made of gamma-ray spectrometry and a Ge-Li detector. The comparison of burn-up values obtained by both destructive and non-destructive methods was made by means of Student's 't' test, and it has shown that the averages of results obtained in each case are equal. (Author)

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

    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.)

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

    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)

  11. Influence to reject effect on tumor cells by pre-irradiation with low dose-rate gamma-rays

    Radiation has been supposed to be harmful no matter how low the dose is. We have, however, observed that low dose-rate irradiation increased the tumor cells rejecting ability in mice. The technique we used was TD50 (tumor dose 50) assay. The TD50 value indicates the number of cells required for successful transplantation to a half of injected site in the transplanted animals. We examined the rejective effect on tumor cell in pre-irradiated and non-irradiated mice using of TD50. Pre-irradiated groups were exposed 137Cs γ-rays at 0.4-1.2 mGy/hr. We found that TD50 values in mice irradiated with a total dose of 250 mGy were increased compared to non-irradiated mice. These results suggested that the low dose-rate irradiation increased, under certain conditions, the tumor cell rejecting ability in mice. (author)

  12. 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

    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)

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

    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

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

    Cadmium sulfide quantum dots 1.3–5.6 nm in size have been synthesized in sodium bis(2-ethylhexy1)sulfosuccinate (AOT)–water–isooctane 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 γ-irradiation reduces the size polydispersity of quantum dots in the micellar system and alters their fluorescent properties. Fluorescence intensity is enhanced after γ-irradiation. The average fluorescence lifetime of single quantum dots sized 5.2±0.4 nm increases from 5.14 to 6.39 ns after γ-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. • γ-Irradiation reduces the size polydispersity of quantum dots in the micellar system. • Fluorescence intensity of CdS quantum dots is enhanced after γ-irradiation. • Fluorescence lifetime of single CdS quantum dots increases after γ-irradiation

  15. Investigations on the effect of gamma-ray irradiation on the gas sensing properties of SnO2 nanoparticles.

    Lavanya, N; Sekar, C; Anithaa, A C; Sudhan, N; Asokan, K; Bonavita, A; Leonardi, S G; Neri, G

    2016-09-23

    In recent years, SnO2 nanoparticles (NPs) have been subjected to various modifications in order to improve their performance in sensing and other applications. Here, we report the synthesis of SnO2 NPs by microwave irradiation, and subsequent exposure to gamma (γ) radiation at different doses (0-150 kGy) to induce desirable physico-chemical properties. The irradiated samples were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM and HR-TEM), and photoluminescence (PL) to evaluate the effect of γ-ray irradiation on their morphology and microstructure. The results revealed that the bulk crystal structure remained unchanged after irradiation, while the existence of defects and a damaged over-layer have been confirmed by PL and HR-TEM respectively. The influence of γ-irradiation on the electrical and CO sensing characteristics was also investigated in the temperature range between 150 and 400 °C. γ-irradiated SnO2 NP based resistive sensors showed better CO sensing characteristics (i.e. higher response and lower working temperature) compared to non-irradiated SnO2. Upon optimizing the γ-ray dose irradiation level and working temperature, a ten-fold enhancement in the response to CO has been achieved (R/R 0 = 12 to 50 ppm of CO in air) in 50 kGy irradiated SnO2 NP based sensors operating at 150 °C. A possible mechanism for the enhanced sensing performance of γ-irradiated SnO2 NPs has been proposed. PMID:27532479

  16. Gamma Ray Bursts

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  17. Gamma-Ray Bursts

    Gehrels, Neil; Mészáros, Péter

    2012-08-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow.

  18. Gamma Ray Bursts

    Gehrels, Neil; 10.1126/science.1216793

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day, last typically 10s of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  19. SVOM gamma ray monitor

    2010-01-01

    The space-based multi-band astronomical Variable Object Monitor(SVOM) mission is dedicated to the detection,localization and broad-band study of gamma-ray bursts(GRBs) and other high-energy transient phenomena.The gamma ray monitor(GRM) onboard is designed to observe GRBs up to 5 MeV.With this instrument,one of the key GRB parameters,Epeak,can be easily measured in the hard X-ray band.It can achieve a detection rate of 100 GRBs per year which ensures the scientific output of SVOM.

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

    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 γ rays and proton beams. Irradiations were performed with a 137Cs γ 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 α 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 (2.69±0.08 keV/μm). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with γ 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 γ 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 γ 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)

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

    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)

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

    Total aerobic bacteria in spices used in this study were determined to be 1 x 106 to 6 x 107 per gram. A study on the inactivation of microorganisms in spices showed that doses of 6-9 kGy of EB (electron-beams) or γ-irradiation were required to reduce the total aerobic bacteria to below 103 per gram. However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These differences of radiation sensitivities between EB and γ-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 γ-rays. (author)

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

    The blend rubbers were prepared by mixing γ-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

  4. Low temperature gamma-ray irradiation effects on polymer materials. Pt. 3: Gas evolution and change of molecular weight

    Gas analysis was carried out after gamma-irradiation at room temperature (RT) and 77K for poly(methyl methacrylate) (PMMA) and glass fiber reinforced plastic (GFRP). The yield of hydrogen from irradiated PMMA and GFRP was nearly the same at RT and 77K. The yield of CH4, CO and CO2, however, was much less at 77K than at RT; these results were in good accordance with results of mechanical properties. Changes in molecular weight and network structure were also studied. The radiation degradation mechanism and its temperature dependence is discussed. (Author)

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

    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

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

    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

  7. The early response of pineal N-acetyltransferase activity, melatonin and catecholamine levels in rats irradiated with gamma rays

    Male Wistar rats adapted to an artificial light-dark regimen were whole-body gamma-irradiated with a dose of 14.35 Gy. Irradiation, sham-irradiation and decapitation 30, 60 and 120 min after the exposure were performed between 2000 h and 0100 h in the darkness. The serotonin N-acetyltransferase activity (NAT), the concentration of melatonin and corticosterone were also determined. Ionizing radiation did not change the activity of NAT, the key enzyme of melatonin synthesis; however, it decreased the concentration of pineal melatonin. The concentration of pineal dopamine and norepinephrine decreased 30 and 120 min after exposure, while the concentration of epinephrine was elevated 30 min after irradiation, though later it was markedly decreased. The serum melatonin level was not changed but an increase in corticosterone level was observed. In the early period after exposure a decrease in pineal melatonin occurred, accompanied by a decrease in pineal catecholamines. On the contrary, in the phase of developed radiation injury the signs of increased melatonin synthesis were observed on days 3 and 4 after the exposure. (author) 6 figs., 25 refs

  8. Use of delayed gamma rays for active non-destructive assay of 235U irradiated by pulsed neutron source (plasma focus)

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of 235U by monitoring its delayed high energy γ-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 235U in the oxide samples with this set-up is estimated to be 14 mg

  9. Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

    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 γ-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.

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

    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...

  11. Cloning and molecular analysis of GA2ox1 gene mutation generated by gamma-ray 60Co irradiation in mutagenized Tamxoan - TDB06 rice cultivar

    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)

  12. Selection and Semi-Dwarf Allele Mutants Segregation Pattern as the Result of Gamma Ray Irradiation of West Sumatera Black Rice

    Benny Warman

    2015-01-01

    Full Text Available Black rice is a local rice originating from East Pasaman which has a low yield potential, long panicles, too high of longevity and plant height and soeasily fall. To reduce  plant height has been irradiated rice seedsas much as 200 grams of black rice with a dose of 200 Gy of gamma rays. This study aimed to obtain information about the frequency of mutant semi-dwarf/dwarf and segregation patterns in mutant alleles black rice as the genetic improvement of West Sumatra local rice through mutation induction.  From the selection of the M2 generation gained 31 candidates dwarf/semi dwarf mutant frequency of 0.062%. also obtained information that the segregation of alleles that make up the character ofthe semi dwarf/dwarf rodon rice mutant semi dwarf/dwarf trunked together with the distribution pattern of segregation according to Mendel's Law. On the character of the semi-dwarf/dwarf stem is influenced by one or two groups of alleles, where one of the alleles controlling the properties of semi-dwarf/dwarf stem, while the other controls the high stemproperties. Alleles from each group are in a locus that its chromosomes separate.It is evident that the semi-dwarf/dwarf on the mutant is occured due to one or more alleles is dominant on the high stem properties controlling alleles group toward the recessive.

  13. The Improvement of Atomita-4 Rice Variety Through Gamma Rays Irradiation of F1 Seeds from Atomita-4/Ir-64 Crossing

    Atom ita-4 rice variety was crossed with IR-64 variety in the greenhouse at the Center for Application of Isotopes and Radiation-Batan, Pasar jumat in the wet season of 1994/1995. F1 Seeds derived from Atomita-4/IR-64 crossing were irradiated by gamma rays at of 0.2 kGy dose. F1 seeds were grown to obtain F2 M2 seed, and then selection of pedigree were carried out at F2 generation. Six mutants lines were obtained purified and screened on biotypes 1, 2 and 3 brown plant hopper and bacterial leaf blight resistance by IRRI standard screening methods. The six mutant lines were tested for their potential yield at Pusakanegara and then continued tested in yield multi location test at several locations in Indonesia. Results of the screening test to brown plant hopper showed that two mutant lines Obs-1653/PsJ and Obs-1656/PsJ were resistant to biotype 1, biotype 2 and medium resistant to biotype 3. Obs-1653/PsJ and Obs-1656/PsJ also showed resistance to bacterial leaf blight strain 3 and medium resistance to strain 4. Results in the yield multi location test showed that Obs-1653/PsJ and Obs-1656/PsJ have highest yielding potential compared to IR-64 and Memberamo varieties. Those two mutant lines were released as new varieties under the name Merauke and Kahayan in 2001 and 2003 respectively. (author)

  14. Syntheses, Spectral, Surface Morphological and Gamma Ray Irradiation Studies of Some Oxomolybdenum(V) and Dioxomolybdenum(VI) Complexes of an Azo Dye Derived from 4-aminoantipyrine

    Syntheses of some novel oxomolybdenum(V) and dioxomolybdenum(VI) complexes with an azo dye meth-oxyphenolazoantipyrine (HL) derived from 4-aminoantipyrine and 2-methoxyphenol are reported. The complexes have been characterized by elemental analyses, molar conductance, magnetic susceptibility data, IR, UV-Vis, 1H NMR, EPR and FAB mass spectral studies. The physicochemical studies and spectral data indicate that HL acts as a bidentate chelating ligand. The complexes have the general formulae [MoO(HL)XCl2] and [MoO2(HL)XCl],where X=Cl, NCS or NO3. All the complexes are found to have distorted octahedral geometry. Structural and morphological characterization of the complexes [MoO(HL)Cl3](1) and [MoO2(HL)Cl2](4) before and after gamma ray irradiation,was performed by X-ray diffraction and scanning electron microscopy(SEM). The ligand and the complexes were screened for their possible antimicrobial activities

  15. Thermoluminescence characteristics of Nd-doped SiO2 optical fibers irradiated with the 60Co gamma rays

    Thermoluminescence (TL) properties (radiation sensitivity, dose response, signal fading) of Nd-doped SiO2 optical fibers irradiated with 1.25 MeV photons to 1–50 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

  16. Irradiation and ESR analysis temperature dependence of the gamma-ray response of alanine-polystyrene dosimeters

    Response characteristics of the alanine-polystyrene dosimeter were studied at an absorbed dose of 5 kGy over the low irradiation temperature range -196 ∼ 30oC, and the ESR analysis temperature range 0 ∼50oC in the dose range 0.1 ∼ 10 kGy. The irradiation temperature coefficient previously estimated for the temperature range from 0 ∼ 70oC (+0.24%/.oC) was verified down to -15oC, although about 8% lower values were obtained at -78 and -196oC based on the correction using the above coefficient. ESR intensity decreases with temperature during ESR analysis following the function of the reciprocal of absolute temperature based on Boltzmann's constant. The average temperature coefficient for three different dose levels during ESR analysis of the alanine-polystyrene dosimeter is -0.25%/K in the temperature range 0 ∼ 50oC. (Author)

  17. Chemist's gamma-ray table

    An edited listing of gamma-ray information has been prepared. Prominent gamma rays originating from nuclides with half lives long enough to be seen in radiochemical experiments are included. Information is ordered by nuclide in one section and by energy in a second section. This shorter listing facilitates identification of nuclides responsible for gamma rays observed in experiments

  18. Changes in the microflora of Vienna sausages after irradiation with gamma-rays and storage at 10 deg C

    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)

  19. Some aspects of the behavior at different ages of Ceratitis capitata (Wiedemann, 1824) (Diptera-Tephritidae) irradiated with gamma rays

    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

  20. Approach to the resistance of exportation tebo worms when irradiated with gamma ray through a quarantine treatment

    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)

  1. Studies into the variability in the tryptophan content induced by irradiation with gamma rays for different wheat varieties

    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)

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

    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)

  3. Study of the ionization of alkane-electron scavenger reactant mixtures irradiated by 60Co gamma rays

    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

  4. Gamma-ray irradiation hardness of arrayed silicon microhole-based radial p–n junction solar cells

    The γ-ray irradiation hardness of arrayed silicon microhole-based radial p–n 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 4 µm-pitch ASMRJ SCs with hole arrays' sidewalls both unpassivated and passivated were made and referred to as 4 µm-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 4 µm-U-ASMRJ SCs show a small increase in the initial stage of γ-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 2 µm-U-ASMRJ SCs shows an initial slight ascent by 5.7%. When the radiation doses grow to 8 × 106 rad, the average conversion efficiency degradation rates for the 2 µm- and 4 µm-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)

  5. Chemical changes in the chloroform-paraffin-dye system irradiated with 60Co gamma-rays, 2

    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, ΔE, 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)

  6. Irradiation and ESR analysis temperature dependence of the gamma-ray response of alanine-polystyrene dosimeters

    Kojima, T.; Morishita, N.; Itoh, H. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Biramontri, S. [Office of Atomic Energy for Peace, Bangkok (Thailand)

    1996-04-01

    Response characteristics of the alanine-polystyrene dosimeter were studied at an absorbed dose of 5 kGy over the low irradiation temperature range -196 {approx} 30{sup o}C, and the ESR analysis temperature range 0 {approx}50{sup o}C in the dose range 0.1 {approx} 10 kGy. The irradiation temperature coefficient previously estimated for the temperature range from 0 {approx} 70{sup o}C (+0.24%/.{sup o}C) was verified down to -15{sup o}C, although about 8% lower values were obtained at -78 and -196{sup o}C based on the correction using the above coefficient. ESR intensity decreases with temperature during ESR analysis following the function of the reciprocal of absolute temperature based on Boltzmann`s constant. The average temperature coefficient for three different dose levels during ESR analysis of the alanine-polystyrene dosimeter is -0.25%/K in the temperature range 0 {approx} 50{sup o}C. (Author).

  7. Gamma ray beam transmutation

    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

  8. Gamma ray camera

    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)

  9. Effect of pelvic irradiation of lactose absorption. [. gamma. rays or x rays were used in gynecologic malignancy therapy

    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.

  10. Formation of radical cations and dose response of alpha-terthiophene-cellulose triacetate films irradiated by electrons and gamma rays

    Emmi, S S; Ceroni, P; D'Angelantonio, M; Lavalle, M; Fuochi, P G; Kovács, 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.

  11. Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

    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.

  12. Effect of gamma-ray irradiated natural herbal extracts on NF-kB activation in HMC-1 cells

    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

  13. 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

    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.

  14. 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

    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

  15. 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

    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.

  16. Influence of dose rate on leukemogenesis in mice irradiated by gamma rays at a high dose rate or low dose rates

    The purpose of this study was to assess the extent of the effect of dose rate on tumorigenesis, focusing on myeloid leukemia, one of the typical neoplasias induced by radiation. In the experiment, C3H/He male mice were irradiated with gamma-rays at various doses at a dose rate of 0.88Gy/min, or 0.30mGy/min or 0.016mGy/min, and equations of dose response curves for leukemia were derived from data on the incidence in each group by the least square method. Each equation fitted well with the linear quadratic equation by coefficiency of more than 90%. The extent of the dose rate effect was expressed as dose and dose rate effectiveness factor (DDREF) based on the definition by ICRP-Publication 60. We obtained DDREF by dividing the slope factor of the tangential line of group H (0.88Gy/min) by that of group L-1 (0.30mGy/min) or L-2 (0.016mGy/min), the tangential lines being drawn from the value of the incidence of the control group on the dose response curve. The value of group H to group L-1 was 12.00/1.71=7.022, and that of group H to group L-2 was 12.00/2.56=4.69. These values indicated that reduction of the dose rate caused a decrease in the induction of leukemia, ranging between the values 2 and 10 in the NCRP 1990 report. (author)

  17. Age and sex dependence in tumorigenesis in mice by continuous low-dose-rate gamma-ray whole-body irradiation

    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)

  18. Cellular response to low Gamma-ray doses

    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)

  19. Influence of the intensity of the first dose on the extent and duration of the protective effect induced in Saintpaulia ionantha (Wendl. ) leaves irradiated by gamma rays

    Duron, M. (I.N.R.A., Beaucouze, 49 - Angers (France)); Dixon, B. (Centre regional de Lutte contre le Cancer, 49 - Angers (France))

    1982-09-27

    If a 24 hrs. time interval is left between two gamma-rays doses, first doses ranging from 5 to 30 Gy are efficient to protect the leaves against a challenging letal dose of 70 Gy. The duration of the protective effect increases from 6 to 21 days when the first dose increases from 5 to 30 Gy.

  20. Influence of the molecular modifications on the properties of EPDM elastomers under irradiation

    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, γ-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

  1. Airborne gamma-ray spectrometry

    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. ...

  2. Cosmic gamma rays from quasars

    The diffuse gamma radiation consists of the galactic and extragalactic components. The latter component is of special interest on account of its cosmological significance. Following the method recently proposed to estimate the gamma ray flux from galaxy clusters, and the detection of gamma rays from the quasars 3C273, the data base of the SAS II satellite was used to estimate the contribution from quasars to the extragalactic gamma ray flux. It is shown that quasars as a whole are significant gamma ray contributors, the average gamma ray flux per quasar in the energy range 35 MeV to 100 Mev being (1.3 + or - 0.9) x .00001 cm(-2)s(-1)sr(-1)

  3. Cosmic gamma rays from quasars

    Lau, M. M.; Young, E. C. M.

    1985-01-01

    The diffuse gamma radiation consists of the galactic and extragalactic components. The latter component is of special interest on account of its cosmological significance. Following the method recently proposed to estimate the gamma ray flux from galaxy clusters, and the detection of gamma rays from the quasars 3C273, the data base of the SAS II satellite was used to estimate the contribution from quasars to the extragalactic gamma ray flux. It is shown that quasars as a whole are significant gamma ray contributors, the average gamma ray flux per quasar in the energy range 35 MeV to 100 Mev being (1.3 + or - 0.9) x .00001 cm(-2)s(-1)sr(-1).

  4. Protective and/or recovering effects of various kinds of chemicals and drugs to the hemopoietic injuries caused by the irradiation of /sup 60/Co. gamma. -rays in the mice

    Kagimoto, Akio

    1987-01-01

    We have injected eleven kinds of chemical substances and drugs intraperitoneally in the male ddN mice, and studied the relative protective and/or recovering effects of them to the hemopoietic injuries caused by the whole body irradiation of 600R of /sup 60/Co ..gamma..-rays. Good radioprotective activity on bone marrow cells in the irradiated mice was found, when we administered AET (S, 2-aminoethylisothiuronium Br. HBr) before irradiation, 5-HTP (5-hydroxytryptophane) in low dosage before irradiation, Glutathione before irradiation, or Serotonin (5-HT; 5-hydroxytryptamine) in high dosage before irradiation. Good radioprotective or recovering activity was observed on the weight of the spleen, by Serotonin in high and low dosage before irradiation, or DBCC (5,6-dimethyl benzimidazolyl cobamide coenzyme; Vitamin B/sub 12/) after irradiation. Positive responses of reticulocytes, erythrocytes, hemoglobin, and hematocrit were obtained in the irradiated mice, when we administered Serotonin in high dosage before irradiation, MET (S-Methyl-l-cysteine sulfoxide) before irradiation, a cocktail of Periactin (Cyproheptadine hydrochloride) and Serotonin before irradiation, MET before and after irradiation or Nucleo (a mixture of products made by degrading yeast-RNA) after irradiation respectively. A good response in leukocyte count was observed when Serotonin in high dosage before irradiation was administered, and in granulocyte count by Serotonin in high dosage before or 5-HTP in low dosage before irradiation. Lymphocyte count was protected or recovered by Serotonin in high dosage before or Nucleo after irradiation. Thrombocyte count was protected by Serotonin in high and low dosage before, Glutathione before, or AET before irradiation.(author).

  5. 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

    Ma, Liang; Wang, Mozhen; Ge, Xuewu

    2013-09-01

    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.

  6. Gamma ray analysis of multi-component material

    A method and apparatus is disclosed for analyzing a multi-component material having at least three components using gamma radiation having at least two different energies. Upon irradiation of at least a sample of material, the multi-energy gamma rays which are propagated through the sample are detected. The intensity of the detected gamma rays is measured and the amount of at least one of the components of the material is determined by solving a set of simultaneous equations. (author)

  7. Wear properties of nano-Al2O3/UHMWPE composites irradiated by gamma ray against a CoCrMo alloy

    Nano-Al2O3/ultra-high molecular weight polyethylene (UHMWPE) composites were prepared by hot pressing and then radiated by a gamma ray in doses of 120 kGy, 250 kGy and 500 kGy. The hardness of the composites was tested. The friction and wear properties against a CoCrMo alloy were also tested on a knee simulator under physiological saline solution lubrication. The morphologies of worn surfaces were examined under an optical microscope. The structure of the sample was analyzed by IR and XRD tests. The results showed that the wear rate of UHMWPE decreased when filled with a proper amount of nano-Al2O3, and with an increment of the radiation dose of gamma rays. It was found that filling nano-Al2O3 into UHMWPE can inhibit the effect of oxidation during the radiation procedure

  8. Influence of stresses on the mechanical properties of charged elastomers during their aging by irradiation

    The damage in time of materials can have determining consequences on their mechanical properties. The aim of this work is to study the aging by irradiation of charged elastomers, and more particularly of charged aluminium tri-hydrated ethylene propylene diene polymers (EPDM). The evolution of this type of materials submitted to a gamma irradiation aging in presence of oxygen is presented. The materials have been tested and characterized at different aging levels, chemical, microstructural and mechanical: here only the results for small deformations and big deformations (uniaxial traction) are presented. From these analyses, it has been revealed a competition between the reticulation/chains cleavages during irradiations and the particular influence of the stresses on the mechanical properties during aging. (O.M.)

  9. Planetary gamma-ray spectroscopy

    The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed

  10. Planetary gamma-ray spectroscopy

    Reedy, R.C.

    1978-01-01

    The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed.

  11. The effects of γ-ray irradiation on the properties of polyolefin elastomer composite material

    The Polyolefin elastomer/Magnesium hydroxide (POE/MH) composite material was irradiated using 60Co γ- ray to study the radiation effects on tensile properties, flame retardancy and thermal stability. The gel content result showed that the gel content of the POE reached 49.5% at doses 150 kGy. For POE/MH in irradiation doses 75 kGy, the gel content increased by 57.9% compared with non-irradiated samples. Tensile test showed that the tensile strength of the POE irradiated at doses 75 kGy increased by 63.3% compared with the non-irradiated samples. The tensile strength of the POE/MH irradiated at doses 125 kGy, increased by 85.5% from the non-irradiated POE/MH. Thermal mechanical performance test showed that the softening point of the composite with flame retardant content of 120 shares was 194.0℃ for sample irradiated at doses 125 kGy, while that was 131.9℃ for the sample without irradiation. In flame experiment, the limiting oxygen index (LOI) of the composite material with MH content of 120 shares is 32 after irradiating at doses 125 kGy. And meanwhile, the irradiation could effectively improved the melt dropping property of the flame-retardant material in the process of combustion. The droplet is gradually reduced with the radiation dose increased. The above data indicated that seemly irradiation could effectively enhance the tensile properties, flame retardancy and thermal stability of the flame-retardant composite material. (authors)

  12. Gamma-ray Pulsar Revolution

    Caraveo, Patrizia A.

    2013-01-01

    Isolated Neutron Stars (INSs) were the first sources identified in the field of high-energy gamma-ray astronomy. At first, in the 70s, there were only two identified sources, the Crab and Vela pulsars. However, although few in number, these objects were crucial in establishing the very concept of a gamma-ray source. Moreover, they opened up significant discovery space both in the theoretical and phenomenological fronts. The need to explain the copious gamma-ray emission of these pulsars led t...

  13. Gamma ray irradiation induced degradation in ultra-thin silica layers; Degradation induite par l`irradiation gamma dans les couches d`oxyde de silicium ultra -minces

    Aassime, A.; Salace, G.; Petit, C. [Reims Univ., 51 (France); Sarrabayrouse, G.J. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France). Lab. d`Automatique et d`Analyse des Systemes

    1995-12-31

    In this paper, the influence of gamma irradiation on the electrical properties of Metal-Oxide-Semiconductor (MOS) with an ultra-thin silica layer N{sub 2}O nitrided or not is investigated. Mainly electron trapping, defects generation and breakdown during electrical stress are studied. (author). 12 refs.

  14. Gamma rays at airplane altitudes

    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

  15. Peculiarities of agaricus bisporus (J. Lge) Imbach strains obtained under the. gamma. -ray effect

    Stanek, M.; Dudka, Yi.O.; Byis' ko, N.A.; Vasser, S.P.; Srv, A.; Kolesnichenko, L.P.; Yablons' kij, Yi. (Ceskoslovenska Akademie Ved, Novy Hradek. Mikrobiologicky Ustav; AN Ukrainskoj SSR, Kiev. Inst. Botaniki)

    A technique of irradiation of Agaricus bisporus (J.Lge) Imbach strains by gamma-rays is described, characteristics of strains, received during irradiation are given (productivity, protein content). The efficiency of gamma-ray usage in A bisporus selection is considered.

  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

    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

    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. Magnetic angle for gamma rays

    In December 2002 astronomers at the University of California in Berkeley got a lucky break. A bright gamma-ray burst appeared in the sky within 18 degrees of the Sun, which was close enough to be picked up by the RHESSI solar satellite. Analysing data from the satellite, Wayne Coburn and Steven Boggs made the stunning discovery that the gamma rays from the burst - named GRB021206 - were linearly polarized. And not just by any amount, but by 80% - the maximum polarization theoretically possible. The discovery represents a major breakthrough in gamma-ray astronomy (Nature 423 415).Gamma-ray bursts are the most energetic events in the universe, typically corresponding to the conversion of 1% of the mass of the Sun into energy. Every day an average of about one of these brief flashes of gamma rays - which come from any direction in the sky and last a few tens of seconds - are detected. Observations of the optical afterglow of the bursts reveal that they originate in galaxies that are several billions of light-years away. But what causes the bursts, and how the gamma rays are actually produced, have, until recently, remained a mystery. It has been suggested that gamma-ray bursts result from supernovae - the explosions of massive stars that have used up all their fuel - and that the bursts might be the 'birth cries' of black holes. Some of this evidence is circumstantial. It is known, for example, that the host galaxies of the bursts are regions where massive stars are copiously forming. However, observations of the afterglow of GRB980425 in 1998 revealed a spectral signature that would be expected for a supernova. This provided the first compelling, but inconclusive, direct evidence for the link between gamma-ray bursts and supernovae. In March this year, however, this link was dramatically confirmed. The HETE-2 satellite detected a spectacular gamma-ray burst that was among the closest and brightest ever observed. GRB030329 was just two billion light-years away, which

  19. Surface characteristics of UV-irradiated polyurethane elastomers extended with α, ω-alkane diols

    Polyurethane elastomers (PUEs) based on 4,4'-diphenylmethane diisocyanate (MDI), poly (ε-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

  20. Chromosomal mutations and chromosome loss measured in a new human-hamster hybrid cell line, ALC: studies with colcemid, ultraviolet irradiation, and 137Cs gamma-rays

    Kraemer, S. M.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

    1997-01-01

    Small mutations, megabase deletions, and aneuploidy are involved in carcinogenesis and genetic defects, so it is important to be able to quantify these mutations and understand mechanisms of their creation. We have previously quantified a spectrum of mutations, including megabase deletions, in human chromosome 11, the sole human chromosome in a hamster-human hybrid cell line AL. S1- mutants have lost expression of a human cell surface antigen, S1, which is encoded by the M1C1 gene at 11p13 so that mutants can be detected via a complement-mediated cytotoxicity assay in which S1+ cells are killed and S1- cells survive. But loss of genes located on the tip of the short arm of 11 (11p15.5) is lethal to the AL hybrid, so that mutants that have lost the entire chromosome 11 die and escape detection. To circumvent this, we fused AL with Chinese hamster ovary (CHO) cells to produce a new hybrid, ALC, in which the requirement for maintaining 11p15.5 is relieved, allowing us to detect mutations events involving loss of 11p15.5. We evaluated the usefulness of this hybrid by conducting mutagenesis studies with colcemid, 137Cs gamma-radiation and UV 254 nm light. Colcemid induced 1000 more S1- mutants per unit dose in ALC than in AL; the increase for UV 254 nm light was only two-fold; and the increase for 137Cs gamma-rays was 12-fold. The increase in S1- mutant fraction in ALC cells treated with colcemid and 137Cs gamma-rays were largely due to chromosome loss and 11p deletions often containing a breakpoint within the centromeric region.

  1. 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)

    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.)

  2. Gamma-ray Imaging Methods

    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.

  3. Human lymphocytes response to low gamma-ray doses

    Radiation and non-radiation workers lymphocytes 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 Hsp25, Hsp60, Hsp70 and Hsp90; from these, only Hsp70 protein was detected before and after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 70.5 μGy gamma-ray dose, radiation worker's lymphocytes expressed more Hsp70 protein, than non radiation workers' lymphocytes, indicating a larger tolerance to gamma rays (gammatolerance), due to an adaptation process developed by his labor condition

  4. Response of human lymphocytes to low gamma ray doses

    Radiation and non-radiation workers lymphocytes 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 Hsp25, Hsp60, Hsp70 and Hsp90; from these, only Hsp70 protein was detected before and after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 70.5 mGy gamma-ray dose, radiation worker's lymphocytes expressed more Hsp70 protein, than non-radiation workers' lymphocytes, indicating a larger tolerance to gamma rays (gamma tolerance), due to an adaptation process developed by their labor condition (Au)

  5. Property of laser Compton scattering gamma-ray beam and application

    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)

  6. The GRAD gamma ray spectrometer

    Rester, A.C.; Piercey, R.B.; Eichhorn, G.; Coldwell, R.L.; McKisson, J.M.; Ely, D.W.; Mann, H.M.; Jenkins, D.A.

    1986-02-01

    A gamma-ray spectrometer for an upcoming space shuttle mission is described. Consisting of a 150 cm/sup 3/ n-type germanium detector set inside active shielding of bismuth germanate and plastic scintillator, the instrument will be used in studies of the Orbiter background and the galactic center.

  7. The GRAD gamma ray spectrometer

    A gamma-ray spectrometer for an upcoming space shuttle mission is described. Consisting of a 150 cm3 n-type germanium detector set inside active shielding of bismuth germanate and plastic scintillator, the instrument will be used in studies of the Orbiter background and the galactic center

  8. Short duration gamma ray bursts

    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 (90 < 2 s). Finally, we conclude with a brief sketch of a new unified model for long and short GRBs.

  9. Gamma ray slush hydrogen monitor

    Singh, Jag J.; Shen, Chih-Peng; Sprinkle, Danny R.

    1992-01-01

    Mass attenuation for 109Cd radiation have been measured in mixtures of phases and in single phases of five chemical compounds. As anticipated, the mass attenuation coefficients are independent of the phases of the test chemicals. It is recommended that a slush hydrogen monitoring system based on low energy gamma ray attenuation be developed for utilization aboard the NASP.

  10. Periodicities in gamma ray bursts

    Gamma ray burst models based on magnetic neutron stars face a problem of account for the scarcity of observed periods. Both this scarcity and the typical period found when any is detected are explained if the neutron stars are accreting in binary systems

  11. Activation of wine bentonite with gamma rays

    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

  12. The Gamma-ray Sky with Fermi

    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.

  13. Gravitational microlensing of gamma-ray blazars

    F. Torres, Diego; E. Romero, Gustavo; F. Eiroa, Ernesto;

    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)....

  14. 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

    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)

  15. Gamma Ray Spectroscopy with Scintillation Light in Liquid Xenon

    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.

  16. Airborne gamma ray spectrometer surveying

    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

  17. Compton suppression gamma ray spectrometry

    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)

  18. Neutrinos from Gamma Ray Bursts

    Mannheim, K

    2000-01-01

    The observed fluxes of cosmic rays and gamma rays are used to infer the maximum allowed high-energy neutrino flux allowed for Gamma Ray Bursts (GRBs), following Mannheim, Protheroe, and Rachen (2000). It is shown that if GRBs produce the ultrahigh-energy cosmic rays, they should contribute (a) at least 10% of the extragalactic gamma ray background between 3 MeV and 30 GeV, contrary to their observed energy flux which is only a minute fraction of this flux, and (b) a cumulative neutrino flux a factor of 20 below the AMANDA (Neutrino 2000) limit on isotropic neutrinos. This could have two implications, either GRBs do not produce the ultrahigh energy cosmic rays or that the GRBs are strongly beamed and emit most of their power at energies well above 100 GeV implausibly increasing the energy requirements, but consistent with the marginal detections of a few low-redshift GRBs by MILAGRITO, HEGRA-AIROBICC, and the Tibet-Array. All crucial measurements to test the models will be available in the next few years. Thes...

  19. High dose gamma-ray standard

    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%

  20. 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

    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

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

    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 γ-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 γ-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 γ-ray dose rate for the two elastomers are presented in this paper.

  2. Mutagenesis by gamma-rays in grain sorghum

    This study was undertaken to get information on irradiation - induced mutation in grain sorghum. Dry seeds of uniform size of three improved local varieties were irradiated with gamma-rays from 60Co source. Doses administered were 10, 20, 30 and 40 KR at the rate of 4.48 KR/minute. Observation for length, breadth and weight, of panicles grain yield etc were recorded and the data were statistically analysed. (author)

  3. Effect of gamma rays on corn grains. Pt. 3. Effect of post-irradiation storage on some technological properties of corn grains and fatty acids

    Roushdi, M.; Fahmi, A.A.; Sarhan, M.A.

    1981-05-01

    The effect of storage after irradiation of corn grains on steeping process, starch isolation, quality of by-products and fatty acids composition of germ oil was investigated. It was found that post-irradiation storage led to a decrease in water absorption and protein solubilization during steeping process. The starch yield was lower, contained a high percentage of protein and was darker from above 500 Krads. Post-irradiation caused a change in the proportions and disappearance or induced new fatty acids in the corn germ oil.

  4. Repeated 0.5 Gy gamma-ray irradiation attenuates autoimmune disease in MRL-lpr/lpr mice with up-regulation of regulatory T cells

    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

  5. Obtainment of a drug delivery system from PVAL irradiated by gamma rays; Obtencao de um sistema de liberacao controlada de drogas a partir do PVAL irradiado com radiacao gama

    Terence, Mauro Cesar

    2002-07-01

    The poly(vinyl alcohol) (PVAL) is a polymer used as biomaterial. In this work the PVAL was irradiated by gamma rays from {sup 60}Co 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 (G{sub cross}-l{sub ink}= 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 {center_dot}OH, RO{center_dot} and ROO {center_dot} 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)

  6. Optical evidence for the effect of gamma-ray irradiation on ferroelectric Pb(Zr0.52Ti0.48)O3 thin films

    Lim, Junhwi; Lee, Y. S.; Yang, Sun A.; Bu, Sang Don

    2016-06-01

    We investigated the visible emission property of Pb(Zr,Ti)O3 (PZT) thin films irradiated with gammy-ray (γ-ray) irradiated at various total doses up to 1000 kGy. The PZT thin films were prepared on Pt/Ti/SiO2/Si substrates by using a sol-gel method with a spin-coating process. The visible emission was found to emerge near 550 nm upon γ-ray irradiation, and the intensity of the emission increased with increasing dose. The spectrum of the γ-ray-induced emission was quite narrow, which was quite different from that due to normal defects such as oxygen vacancies. We suggest that the γ-ray irradiation generates inside the PZT films a specific type of defect state that can be detected by using low-temperature photoluminescence spectroscopy.

  7. Effect of Gamma Ray Irradiation on Epitaxial Pb(Zr,Ti)O3 /SrRuO3 Tunable Varactor Devices

    Barala, Surendra Singh; Banerjee, Nirupam; Kumar, Mahesh

    2016-08-01

    Epitaxial morphotropic PbZr0.52Ti0.48O3 (PZT) thin films were employed to enhance the dielectric tunability of microwave filter devices without compromising the device impedance matching and low bias voltage (electrical properties of the epitaxial PZT varactor devices was investigated as a function of the irradiation dose from 0 kGy to 400 kGy, in terms of the capacitance-voltage ( C- V) characteristics and loss tangent response. With enhancing γ-ray irradiation doses the ferroelectric capacitance was found to decrease accompanying degradation in the loss tangent values. The results indicate that tunability of the epitaxial PZT ferroelectric thin-film capacitors decreased with increasing gamma irradiation dose and degraded ˜25% at 400 kGy dose than unexposed devices. Possible reasons for the degradation behavior of dielectric properties and tunability due to radiation-induced defects has been discussed.

  8. Saturation of polymer yield during postpolymerization of gamma-ray irradiated 2-amino-4-N-methylanilino-6-isopropenyl-1,3,5-triazine

    The postpolymerization of 2-amino-4-N-methylanilino-6-isopropenyl-1,3,5-triazine (AMIT) irradiated in glassy-state with γ-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.)

  9. Body weight and enzymes activities in blood plasma of chickens hatched from eggs irradiated with low level gamma rays before incubation

    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

  10. Effect of serial irradiation of low dose gamma rays on the growth and photosynthesis of red pepper (capsicum annuum L.) plants

    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.

  11. Effect of gamma rays and combined treatment between irradiation and other factors to quality of dried cuttle fish and ready-to eat cuttle fish

    The paper showed that the microbial contamination on dried cuttle fish produced from different sources was rather high: 106 - 108/g of sample. E.Coli, Cl.perfringens, Staphylococcus and fungi were found in all samples. Irradiation dose of 3 kGy combined with NaCl (10%) and benzoate natri 0.2% or NaCl (10%) and sorbate kali (2%) reduced total bacterial counts to 104/g. Microbial contamination on ready-to eat dried cuttle fish was 103/g. The pathogenic bacteria were still found in some cases. Fungi contamination was 102 - 105/g in all tested samples. Samples with initial moisture of 21 -26% irradiated at 2 kGy or without irradiation have been attacked by mould after 1 - 1.5 months of storage while there was no mould growth on samples of 19% moisture treated with 2 kGy or on samples of higher moisture but irradiated at 3 kGy, after 9 months of storage. There was not difference in enumeration of microorganisms in dried cuttle fish at 20 - 24 oC and 30 - 32 oC, as well as for two kinds of packaging. (author). 4 refs, 4 tabs

  12. Stress corrosion crack growth rate of sensitized Type 304 stainless steel during high flux gamma-ray irradiation in 288 degrees C water

    Crack propagation tests in 288 degrees C water were carried out using a 1/4 size compact tension specimen of sensitized Type 304 stainless steel (stress intensity; 25 MPa√m) under γ-ray irradiation (Co-60) with high fluxes of 1.3-2.3 x 103 C/kgh. The intergranular SCC crack growth was slightly accelerated by γ-ray irradiation were at most twice as large as that in unirradiated water. The crack growth rates increased almost linearly with increasing Na2SO4 concentration in irradiated water containing more than 500 ppb dissolved oxygen (DO); in the 900 ppb DO condition, the crack growth rate of 2.6 x 109 m/s in water containing 0.4 μS/cm Na2SO4 was about 5 times larger than that in high purity water of 0.07 μS/cm. Although the NaNO3 addition also enhanced the crack propagation in 500 ppb DO water, NaNO3 was less harmful than Na2SO4 in water. Hydrogen injection of 300-500 ppb into water was beneficial to prevent SCC crack propagation in 288 degrees C water during γ-ray irradiation

  13. Process for producing a collagen web for a transparent artificial cornea and a contact lens by irradiation with ultraviolet or gamma rays

    A process for producing a collagen web for use as an artificial cornea and a contact lens is provided by irradiating an acid soluble collagen web or a swelled collagen web with ultraviolet rays or gamma radiation. Cross-linking is introduced into the molecules forming a noncrystalline portion of the collagen to minimize nonuniformity of construction. In embodiments, the collagen, dissolved in a diluted hydrochloric acid or acetic acid aqueous solution at a concentration of about 0.5% to 1%(pH 2-4), is poured into a suitable container for producing and drying a web. The obtained web is neutralized with ammoniac water or vapor and is washed completely. The web is dipped in a dilute hydrochloric acid or acetic acid aqueous solution (pH 2-4) to well and then irradiated. Cross-linking is introduced, followed by further neutralization with ammoniac vapor. Finally the web is washed, air-dried or kept in water. Alternately, the above 0.5%-1% collagen solution is irradiated to gelatinize it after the oxygen dissolved in the solution is substituted with nitrogen. The irradiated web is neutralized with ammoniac water or vapor, and then washed, air-dried or kept in water. In one example, 0.58% collagen hydrochloric acid solution was poured into a methylmethacrylate box and was air-dried to form a web 0.03mm in thickness. The web was neutralized with ammoniac vapor for 24 hours and dipped to swell in a 0.01N HCl solution for 1 minute. The opposite sides of the web were irradiated with UV-rays at 15W. (Iwakiri, K.)

  14. Ion-induced gamma-ray detection of fast ions escaping from fusion plasmas

    Nishiura, M., E-mail: nishiura@ppl.k.u-tokyo.ac.jp; Mushiake, T. [Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561 (Japan); Doi, K.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe 610-0321 (Japan); Taniike, A.; Matsuki, T. [Graduate School of Maritime Sciences, Kobe University, Kobe 658-0022 (Japan); Shimazoe, K. [Graduate School of Engineering, The University of Tokyo, Tokyo 113-8654 (Japan); Yoshino, M. [Furukawa Co. Ltd., Tsukuba, Ibaraki 305-0856 (Japan); Nagasaka, T.; Tanaka, T.; Kisaki, M. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Fujimoto, Y.; Fujioka, K. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Yamaoka, H. [RIKEN SPring-8 center, RIKEN, Sayo, Hyogo 679-5148 (Japan); Matsumoto, Y. [Tokushima Bunri University, Tokushima 770-8514 (Japan)

    2014-11-15

    A 12 × 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions {sup 9}Be(α, nγ){sup 12}C, {sup 9}Be(d, nγ){sup 12}C, and {sup 12}C(d, pγ){sup 13}C, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gamma-ray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle.

  15. Effect of gamma rays on adult flight agility and distribution of Old World screwworm, Chrysomya bezziana, irradiated at the pupal stage

    The larvae of Old World screwworm, Chrysomya bezziana were reared on a meat-based diet containing: lean minced beef (54%), fresh blood (15% containing 10% EDTA), water (30%) and formalin (0.2%). The developed pupae were separated in plastic containers containing vermiculite or corncob grits and incubated for adult emergence under 28 deg. C and 70% relative humidity. The emerged adults were transferred into the adult cages (made from cloth tissue, black or white), provided with water, honey and sugar. Radiation Treatments: At the 5th day of female age, egging dishes were prepared from ground meat, clotted blood or pieces of liver, oviposition stimulants deg. Cntaining spent medium immersed inside the dish. All the contents were warmed on a hotplate to 37 - 39 deg. C. The egging dishes were provided daily for two hours inside the cage for egg deposition. Egg masses and newly hatched larvae were taken for establishing the laboratory colony. The average larval period was 6.8 days, rate of pupation 93.2%, pupal period 7.6 days and rate of pupal development 79%. Pupae at 2-5 days were irradiated with a Gammacell 220. Percentage pupal development to adults decreased from 82% for non-irradiated pupae, to 3%, 12%, 29% and 22% for pupae irradiated with a dose of 90 Gy at 2, 3, 4 and 6 days age. The lifespan of adults emerged from irradiated pupae decreased with increasing gamma dose. Sixty Gy or less did not have an effect on the ovarian development. No egg hatch resulted from the crosses between treatments of 60 to 90 Gy. Egg hatch was observed only in normal adult crosses or in normal females mated with males emerged from 45 Gy irradiated pupae. Flight Agility Test: A small cylinder was made from transparent paper (10 cm long X 10 cm diameter) and lined by baby powder to avoid adults walking out of the cylinder. A group of adults (newly emerged from irradiated pupae) were left inside each cylinder under appropriate temperature and humidity. Adults with flight ability

  16. Recommended standards for gamma ray intensities

    Bé, Marie-Martine, E-mail: mmbe@cea.fr [LNHB, CEA LIST Saclay, 91191 Gif-sur-Yvette Cedex (France); Chechev, Valery P. [KRI, V.G. Khlopin Radium Institute, St. Petersburg 194021 (Russian Federation)

    2013-11-11

    Gamma ray data are used in more and more areas of application, and so over the years the demand for recommended gamma ray energies and intensities has increased. This paper proposes a list of gamma rays whose intensity is sufficiently well-known and they can be used for the calibration of gamma ray spectrometers and other applications; it is based on studies carried out by an international group of evaluators: the Decay Data Evaluation Project. One goal of this paper is to gather this set of data together in order to facilitate and generalize their use. In the first part, a brief description of the methodology followed throughout the evaluations is given, different methods of gamma ray intensity evaluation are presented, some typical examples of evaluations are shown; in the second part, the list of chosen nuclides is given along with their applications, and finally a list of recommended gamma ray intensities is presented.

  17. Gamma-ray burst polarimeter (GAP)

    The gamma-ray burst polarimeter (GAP: GAmma-ray burst Polarimeter), which had been almost handcrafted by scientists, has succeeded in working normally in interplanetary space, and in detecting the polarization of the gamma-ray from a mysterious astronomical object 'gamma-ray burst'. It is the first result of the detectors in the world exclusively aiming at detecting gamma-ray polarization. We mainly describe the hardware of our GAP equipment and show the method of preparing equipment to work in the cosmic space with a tight budget. The mechanical structure, the electronic circuits, the software on the equipment, the data analysis on the earth, and the scientific results gained by the observation just over one year, are presented after explaining the principle of gamma-ray polarization detection. Our design to protect equipment against mechanical shock and cosmic radiation may provide useful information for future preparation of compact satellite. (J.P.N.)

  18. Measurement of DNA damage induced by irradiation with gamma-rays from a TRIGA Mark II research reactor in human cells using Fast Micromethod.

    Hassanein, Hamdy; Müller, Claudia I; Schlösser, Dietmar; Kratz, Karl-Ludwig; Senyuk, Olga F; Schröder, Heinz C

    2002-06-01

    The Fast Micromethod is a novel quick and convenient microplate assay for determination of DNA single-strand breaks. This method measures the rate of unwinding of cellular DNA upon exposure to alkaline conditions using a fluorescent dye which preferentially binds to double-stranded DNA. Here we applied this method to determine the levels of DNA single-strand breaks in HeLa cells induced by y-irradiation deriving from fission isotopes and activation products at the TRIGA Mark II research reactor in Mainz. An increased strand scission factor (SSF) value, which is indicative for DNA damage, was found at doses of 1 Gy and higher. A similar increase in SSF value, which further increased in a dose-dependent manner, was found in human peripheral blood mononuclear cells after irradiation with 6 MV X-rays from a linear accelerator to give a total exposure of 0.5 to 10 Gy. PMID:12064446

  19. Development of nonhalogen elastomers that withstand high radiation and are flame retarding

    Okamoto, Shinichi; Onishi, Norihiro (Osaka Prefectural Univ., Sakai (Japan)); Taketani, Chikashi; Tanaka, Takuo; Ueda, Yoshihiro

    1991-12-01

    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.).

  20. Activity evaluation from different native or irradiated with 60 Co gamma rays snake venoms and their inhibitory effect on Leishmania (Leishmania) amazonensis

    Cutaneous leishmaniasis is a disease, caused by Leishmania parasites, that occurs frequently in tropical and sub-tropical regions of the world. Skin lesions that could results in disfiguring aspect characterize it. The treatment is based on few drugs as antimony salts or pentamidine that are toxic with increasing resistance by the parasite. Alternative forms of disease treatment are in constant search, including natural components as snake venoms. Previous studies demonstrate that some components of snake venoms have an inhibitory effect against those parasites, including Leishmania species. Although snake venoms presented high toxicity, several methods have been described to detoxify most or some of their toxic components, with favorable results by the use of gamma irradiation. In this report we tested several native and irradiated snake venoms for inhibitory effect against Leishmania (Leishmania) amazonensis parasite and LLCMK2 mammalian cells, with enzymatic tests and electrophoresis. There are significant activity in Acanthophis antarcticus, Agkistrodon bilineatus, Bothrops moojeni, Bothrops jararaca, Hoplocephalus stephensi, Naja melanoleuca, Naja mossambica, Pseudechis australis, Pseudechis colletti, Pseudechis guttatus and Pseudechis porphyriacus, venom being inactive Pseudonaja textilis, Notechis ater niger, Notechis scutatus. Oxyuranus microlepidotus and Oxyuranus scutellatus venoms. After 2 KGy of 60Co irradiation most venom loses significantly their activity. Venoms with antileishmanial activity presented L-amino acid oxidase (L-AO) activity and showed common protein with a molecular weight about 60kDa in SDS-PAGE. These results indicate that L-AO activity in those venoms are probably related with antileishmanial effect. (author)

  1. Study of alteration in the mechanical properties in hybrid nanocomposite of polypropylene/sisal fibers/mineral clay irradiated with gamma rays

    A new material class formed with reinforced filler, hybrid of organic and inorganic materials provides the technological development of materials with modified properties. And among great numbers of properties that can be modified by presence of hybrid filler to stand out the tension resistance. Polymer shows behavior of tensions and deformation that are not related of simple form. The answer of this material at mechanicals solicitations depends of structural factors and externals variables. As structural factors can be, for example, molecular weight, ramifications and crosslink. As external variables can be, for example, temperature, time or velocity of deformation, kind of solicitation and others. This work was possible to verify as nanostructures materials behavior, mechanically, after were submitted gamma radiation. This work utilized as polymeric matrix, recycled polypropylene, and as hybrid filler, a mixture of montimorillonite mineral clay with natural sisal fibers. It is known that form to magnify the tensile resistance is increase the number of crosslink of principal chain for gamma radiation. After irradiation the polypropylene was crosslinked structures that are result recombination of radicals formed during process of irradiation. It.s known that radicals formed occur preferentially in the amorphous region of polymer. Considering that polymeric matrix polypropylene, without addition fillers suffer strong structural influence when irradiated, was possible verify change in the extension, tensile strength and also maxim tensile in rupture, when this matrix was incorporated with fillers hybrids. (author)

  2. Formation of solid particles from aqueous solutions of palladium sulfate and of palladium sulfate-silver sulfate by gamma ray irradiation

    Aqueous solutions containing (a) palladium sulfate (b) palladium sulfate and silver sulfate, and (c) silver sulfate saturated with nitrogen were irradiated with cobalt 60 gamma radiations (dose rate, 2.35 and 11.2 kGy/h; temperature: 10 and 29-45degC). The pH's of the most solutions were 1.43 or 0.43. Formation of fine particles was studied from the decrease of optical absorption of the metal ions, and from mass measurement of solid precipitate. It was found that (1) palladium ion decreased with dose in the solutions (a) and (b) with appearance of continuum spectra from 200-700nm range due to solid particles, and (2) silver ion decreased with increasing dose in solution (b) while it did not decrease in solution (c), and (3) electric conductive precipitate was formed in solution (a) and solution (b), but no precipitate was found in solution (c) by the irradiation. The results indicate that (1) palladium ion was reduced to form metallic precipitate in any condition studied, but (b) silver ion was reduced only in the presence of palladium ion, and (3) bimetallic particles were formed in solution (b). The amounts of the precipitates recovered from the irradiated solutions were 57% for solution (a) and 97% for (b) of the amounts of ions reacted. (author)

  3. Mining Gamma-Ray Burst Data

    Hakkila, Jon; Roiger, Richard J.; Haglin, David J.; Mallozzi, Robert S.; Pendleton, Geoffrey N.; Meegan, Charles A.

    2000-01-01

    Gamma-ray bursts provide what is probably one of the messiest of all astrophysical data sets. Burst class properties are indistinct, as overlapping characteristics of individual bursts are convolved with effects of instrumental and sampling biases. Despite these complexities, data mining techniques have allowed new insights to be made about gamma-ray burst data. We demonstrate how data mining techniques have simultaneously allowed us to learn about gamma-ray burst detectors and data collectio...

  4. Gamma-Ray Astronomy Technology Needs

    Gehrels, N.; Cannizzo, J. K.

    2012-01-01

    In recent decades gamma-ray observations have become a valuable tool for studying the universe. Progress made in diverse 8re1lS such as gamma-ray bursts (GRBs), nucleosynthesis, and active galactic nuclei (AGNs) has complimented and enriched our astrophysical understanding in many ways. We present an overview of current and future planned space y-ray missions and discussion technology needs for- the next generation of space gamma-ray instruments.

  5. Evaluation on radiation features of the KUR deuterium neutron irradiation equipment. Neutron energy spectra and neutron- and gamma-ray absorption dose rate

    The deuterium irradiation equipment at reactor for research in Kyoto University (KUR) was reformed at main aim of upgrading of neutron capture therapy (NCT) from November, 1995 to March, 1996. Neutron energy spectra at reference radiation position evaluated on a partial radiation mode by multiple activated foil method, was introduced. As a result of carrying out a simulation calculation using two dimensional transmission calculation supposing medical radiation using the obtained spectra, experimental results could be followed satisfactorily in total. And, comparison with differential absorption dose rate measured by using twin-type ionization box and semiconductor detector for medical probe was also carried out. (G.K.)

  6. 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

    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

  7. The effect of gamma rays on carrots

    The effects of several doses (5-400 Gy) of gamma rays from a 137Cs source were studied on several biological indices in carrots. Doses higher than 50 Gy reduced the wet weight of the cells in the suspension medium whereas the doses of 5 and 10 Gy affected the wet weight positively and to a lesser extent the dry weight. This may be due to higher water absorption of the irradiated cells since their number was less than that of the control. The different doses did not affect the chromosome number of the cells but reduced the cell division rates. At doses higher than 200 Gy no singel cell was recorded as dividing after two days of irradiation. A week later, however, the cells seemed to have recovered some ability for division, but with an increase of prophase stage in mitosis and also in the mitotic division abnormalities. Cells irradiation with 10 Gy caused the cells to differentiate and to form somatic embryos due to halting the effect of 2,4-D hormon. Higher doses, however, prohibited or reduced cells differentiation, probably due to higher mitotic division abnormalities. Nevertheless, it has been possible to attain mature plants from all treatments except for the 400 Gy. The low doses of 5 and 10 Gy, contrary to the higher ones, affected positively the speed of seed germination, increased the plant height, and also increased the root weight. 11 refs. (author)

  8. Gamma ray induced somatic mutations in rose

    Budwood of 32 rose cultivars (Rosa spp.) was exposed to 3-4 krad of gamma rays and eyes were grafted on Rosa indica var. odorata root stock. Radiosensitivity with respect to sprouting, survival and plant height, and mutation frequency varied with the cultivar and dose of gamma rays. Somatic mutations in flower colour/shape were detected as chimera in 21 cultivars. The size of the mutant sector varied from a narrow streak on a petal to a whole flower and from a portion of a branch to an entire branch. 14 mutants were detected in M1V1, four in M1V2 and three in M1V3. Maximum number of mutations was detected following 3 krad treatment. Eyes from mutant branches were grafted again on root stock and non-chimeric mutants were aimed at by vegetative propagation. Mutants from 11 cultivars only could be isolated in pure form. Isolation of non-chimeric mutants sometimes is difficult due to weak growth of a mutant branch. In such a case, all normal looking branches are removed to force a better growth of the mutant branch. It is advisable to maintain irradiated plants at least for four years with drastic pruning in each year. Nine mutants viz. 'Sharada', 'Sukumari', 'Tangerine Contempo', 'Yellow Contempo', 'Pink Contempo', 'Striped Contempo', 'Twinkle', 'Curio' and 'Light Pink Prize' have already been released as new cultivars for commercialization [ref. MBNL No. 23 and 31] and others are being multiplied and assessed. The mutation spectrum appears to be wider for the cultivars 'Contempo' and 'Imperator'. Pigment composition of the original variety is relevant for the kind of flower colour mutations that can be induced

  9. Monte Carlo simulation of gamma ray tomography for image reconstruction

    The Monte Carlo simulations of known density and shape object was validate with Gamma Ray Tomography in static experiments. An aluminum half-moon piece placed inside a steel pipe was the MC simulation test object that was also measured by means of gamma ray transmission. Wall effect of the steel pipe due to irradiation geometry in a single pair source-detector tomography was evaluated by comparison with theoretical data. MCNPX code requires a defined geometry to each photon trajectory which practically prevents this usage for tomography reconstruction simulation. The solution was found by writing a program in Delphi language to create input files automation code. Simulations of tomography data by automated MNCPX code were carried out and validated by experimental data. Working in this sequence the produced data needed a databank to be stored. Experimental setup used a Cesium-137 isotopic radioactive source (7.4 × 109 Bq), and NaI(Tl) scintillation detector of (51 × 51) × 10−3 m crystal size coupled to a multichannel analyzer. A stainless steel tubes of 0,154 m internal diameter, 0.014 m thickness wall. The results show that the MCNPX simulation code adapted to automated input file is useful for generating a matrix data M(θ,t), of a computerized gamma ray tomography for any known density and regular shape object. Experimental validation used RMSE from gamma ray paths and from attenuation coefficient data. (author)

  10. Monte Carlo simulation of gamma ray tomography for image reconstruction

    Guedes, Karlos A.N.; Moura, Alex; Dantas, Carlos; Melo, Silvio; Lima, Emerson, E-mail: karlosguedes@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Meric, Ilker [University of Bergen (Norway)

    2015-07-01

    The Monte Carlo simulations of known density and shape object was validate with Gamma Ray Tomography in static experiments. An aluminum half-moon piece placed inside a steel pipe was the MC simulation test object that was also measured by means of gamma ray transmission. Wall effect of the steel pipe due to irradiation geometry in a single pair source-detector tomography was evaluated by comparison with theoretical data. MCNPX code requires a defined geometry to each photon trajectory which practically prevents this usage for tomography reconstruction simulation. The solution was found by writing a program in Delphi language to create input files automation code. Simulations of tomography data by automated MNCPX code were carried out and validated by experimental data. Working in this sequence the produced data needed a databank to be stored. Experimental setup used a Cesium-137 isotopic radioactive source (7.4 × 109 Bq), and NaI(Tl) scintillation detector of (51 × 51) × 10−3 m crystal size coupled to a multichannel analyzer. A stainless steel tubes of 0,154 m internal diameter, 0.014 m thickness wall. The results show that the MCNPX simulation code adapted to automated input file is useful for generating a matrix data M(θ,t), of a computerized gamma ray tomography for any known density and regular shape object. Experimental validation used RMSE from gamma ray paths and from attenuation coefficient data. (author)

  11. Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

    pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mmx3 mmx2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract

  12. Influence of gamma ray irradiation and annealing temperature on the optical constants and spectral dispersion parameters of metal-free and zinc tetraphenylporphyrin thin films: A comparative study

    Zeyada, H. M.; Makhlouf, M. M.; El-Nahass, M. M.

    2015-09-01

    In this work, we report on the effect of γ-ray irradiation and annealing temperature on the optical properties of metal-free tetraphenylporphyrin, H2TPP, and zinc tetraphenylporphyrin, ZnTPP, thin films. Thin films of H2TPP and ZnTPP were successfully prepared by the thermal evaporation technique. The optical properties of H2TPP and ZnTPP films were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 2500 nm. The absorption spectra of H2TPP showed four absorption bands, namely the Q, B, N and M bands. The effect of inserting Zn atom into the cavity of porphyrin macrocycle in ZnTPP molecule distorted the Q and B bands, reduced the width of absorption region and influenced the optical constants and dispersion parameters. In all conditions, the type of electron transition is indirect allowed transition. Anomalous dispersion is observed in the absorption region but normal dispersion occurs in the transparent region of spectra. We adopted multi-oscillator model and the single oscillator model to interpret the anomalous and normal dispersion, respectively. We have found that the annealing temperature has mostly the opposite effect of γ-ray irradiation on absorption and dispersion characteristics of these films.

  13. Differential radiosensitivity phenotypes of DNA-PKcs mutations affecting NHEJ and HRR systems following irradiation with gamma-rays or very low fluences of alpha particles.

    Yu-Fen Lin

    Full Text Available We have examined cell-cycle dependence of chromosomal aberration induction and cell killing after high or low dose-rate γ irradiation in cells bearing DNA-PKcs mutations in the S2056 cluster, the T2609 cluster, or the kinase domain. We also compared sister chromatid exchanges (SCE production by very low fluences of α-particles in DNA-PKcs mutant cells, and in homologous recombination repair (HRR mutant cells including Rad51C, Rad51D, and Fancg/xrcc9. Generally, chromosomal aberrations and cell killing by γ-rays were similarly affected by mutations in DNA-PKcs, and these mutant cells were more sensitive in G1 than in S/G2 phase. In G1-irradiated DNA-PKcs mutant cells, both chromosome- and chromatid-type breaks and exchanges were in excess than wild-type cells. For cells irradiated in late S/G2 phase, mutant cells showed very high yields of chromatid breaks compared to wild-type cells. Few exchanges were seen in DNA-PKcs-null, Ku80-null, or DNA-PKcs kinase dead mutants, but exchanges in excess were detected in the S2506 or T2609 cluster mutants. SCE induction by very low doses of α-particles is resulted from bystander effects in cells not traversed by α-particles. SCE seen in wild-type cells was completely abolished in Rad51C- or Rad51D-deficient cells, but near normal in Fancg/xrcc9 cells. In marked contrast, very high levels of SCEs were observed in DNA-PKcs-null, DNA-PKcs kinase-dead and Ku80-null mutants. SCE induction was also abolished in T2609 cluster mutant cells, but was only slightly reduced in the S2056 cluster mutant cells. Since both non-homologous end-joining (NHEJ and HRR systems utilize initial DNA lesions as a substrate, these results suggest the possibility of a competitive interference phenomenon operating between NHEJ and at least the Rad51C/D components of HRR; the level of interaction between damaged DNA and a particular DNA-PK component may determine the level of interaction of such DNA with a relevant HRR component.

  14. Gravitational Waves versus X and Gamma Ray Emission in a Short Gamma-Ray Burst

    Oliveira, F. G.; Rueda, Jorge A.; Ruffini, Remo

    2012-01-01

    The recent progress in the understanding the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst, GRB 090227B, allows to give an estimate of the gravitational waves versus the X and Gamma-ray emission in a short gamma-ray burst.

  15. Effect of different doses of gamma rays and fast neutrons on growth of carrot cellus tissue

    Callus tissue lines of four carrot cultivars, grown on three nutrient media, were irradiated with doses of gamma rays from 260 to 44700 R and fast neutrons from 180 - 21000 rad. Effects similar to those of gamma rays were obtained at lower doses of fast neutrons. The response of callus tissues to irradiation was influenced both by genetic factors and the nutrient medium. Two of the irradiated lines exhibited growth stimulation at low doses and a lower sensitivity to irradiation than did the two other ones. Tissues grown on a medium without kinetin showed the highest stimulation at low doses and the lowest growth depression at higher doses of irradiation. (author)

  16. Synthesis of plum-like and walnut-like polymer microspheres by gamma-ray irradiation induced seed-swelling polymerization

    In this work, micron-scaled sulfonated crosslinked polystyrene (SCPS) microspheres were prepared, and dispersed in water/styrene binary mixture as seed microspheres. The system was irradiated by 60Co γ-rays after single-body swelled, and SCPS microspheres with grooved surface were fabricated. Two parameters, the content of crosslinking agent (DVB) and the sulfonation degree of the original SCPS seed microspheres, which influenced the final microspheres facial morphology were studied. The results show that walnut-like microspheres would be formed when the above two parameters are low, and plum-like microspheres prevail with increase of these two parameters However, the special facial morphology has nothing to do with a certain dose rate range at 44-108 Gy·min-1. This work provides a facile and effective way to prepare polymer microspheres with roughness surface. (authors)

  17. Induction of mutation, through gamma rays, in sugarcane

    Variety buds Co-740 of sugar cane were irradiated with gamma rays 60Co at 0.0, 3.0, 4.0, 5.0, 6.0 and 7.0 kR to study changes in the obtained progeny. Evaluation of the germination capacity, height of plants and morphological changes were studied in the different treatments. (M.A.C.)

  18. Effects of gamma rays on rat vascular smooth muscle fibers

    Modifications of the Vasomotoricity induced by gamma rays have been investigated. Vascular smooth muscle fibres (VSMF) of rat portal vein have been used in this study. Irradiation procedures using a 60 Co source have been carried out as follows: - Whole body irradiation. - Irradiation of isolated portal vein and isolated VSMF. Our results show that : 1-irradiation reduces the functional competition between Mg2+ and Ca2+, thus hyper magnetic Krebs solutions have a negligible effect on irradiated VSMF. 2- irradiation activates Ca2+ influx into the VSMF. Thus the effect of hypocalcemic solutions on irradiated VSMF is minor compared with control. 3- Hyperpotassic solutions provoke titanic contractions with high amplitude on the irradiated VSMF compared with control. 5 figs

  19. Determination of absorbed dose in a patient irradiated by beams of X or gamma rays in radiotherapy procedures. ICRU report 24

    ICRU Report 10d, Clinical Dosimetry, was published in 1963. It covered the steps pertaining to dosimetry in the radiotherapy clinic, from the determination of the output of the therapy machine to the assessment of the tumor dose in the patient. The present report is the second of three reports which are collectively to be regarded as the successor to Report 10d. The first of the three, Report 23, published in 1973, was concerned with those procedures which enable the absorbed dose to be determined at any point in a cuboid water phantom. The present report is concerned essentially with the transition from a water phantom to a human patient. A certain degree of overlap with Report 23 has been inevitable and even desirable and may be summarized as follows: (i) the water phantom is replaced by a patient; and (ii) the experimental technique is replaced by a clinical irradiation procedure. These changes lead to a number of complications which will be discussed in detail: (a) The shape, size and composition of the patient do not correspond to that of the phantom. In particular, the human body has a curved and irregular surface and is heterogeneous in composition. (b) The radiation beam may enter the body obliquely. (c) The position of any given point in the body, relative to the surface and deep anatomy of the patient and to the radiation beam, may not be determinable with the same accuracy as the position of a point in a phantom; furthermore, the position may vary from one irradiation to the next. (d) Achieving a particular pattern of absorbed dose distribution within the body may necessitate the use of more than one radiation beam, or movement of the beam(s); also, the beam(s) may need to be modified in order to take account of surface obliquity and/or body heterogeneity. (e) The practical setting up of the radiation beams with respect to the patient is likely to introduce errors over and above those incurred at the water phantom stage. 193 refs., 25 figs., 12 tabs

  20. Modulated gamma ray beam absorptiometer

    The purpose of this paper is to describe the study and operating of a heavy elements content measuring instrument. This apparatus (French patent n0 2184533, December 16, 1974) uses the absorption of a modulated gamma ray beam to measure the concentration of 5 to 500 g per litre uranium of plutonium solutions with an over 1% accuracy. The activity of the fission products present in the solution may rise to 60 Ci/l. An automatic device suppresses all daily checkings and adjustements. The tension obtained is proportional to the content of the heavy element being measured. The influence of the nitric acid content is twenty times as weak as in the case of a conventional densimeter. This apparatus is particularly adapted to fuel reprocessing plants

  1. Determination of protein content in grains by radioactive thermal neutron capture prompt gamma rays analysis

    The radioactive thermal neutron capture prompt gamma rays technique can be used to determinate the nitrogen content in grains without chemical destruction, with good precision and relative rapidity. This determination is based on the detection of prompt gamma rays emitted by the 14N(n,γ) 15N reaction product. The samples has been irradiated the tanGencial tube of the IEA-R1 research reator and a pair spectrometer has been used for the detection of the prompt gamma rays. The nitrogen content is determinated in several samples of soybean, commonbean, peas and rice, and the results is compared with typical nitrogen content for each grain. (Autor)

  2. Long-term changes in open field activity of male mice irradiated with low levels of gamma rays at late stage of development

    The open field activity of first generation (F1) hybrid male C57BL/6 x C3H mice irradiated with γ-rays on the 14th day of gestation was studied at the following ages: 6-7 months, 12-13 months and 19-20 months. Doses were 0.1 Gy or 0.2 Gy. Open field activity was recorded with a camera. The camera output signal was recorded every sec through an A/D converter to a personal computer. The field was divided into 25 units of 8 cm square. All recordings were continuous for 60 min. The time which the 0.2-Gy group recorded at 6-7 months, spent in the 4 squares in the corner fields was high in comparison with the control group at the same age. The walking distance of the 0.1-Gy group recorded at 12-13 months was longer than that for the age matched control group. No effect of radiation was found on any of the behaviors observed and recorded at 19-20 months. The results demonstrate that exposure to low levels of γ-rays on the 14th day of gestation results in behavioral changes, which occur at 6-7 and 12-13 months but not 19-20 months. (author)

  3. Application of gamma-ray irradiation technique to select, create and develop super rice with high quality to substitute the imported hybrid rice

    Three varieties NPT3, BQ and TQ14 were selected by irradiation ray source Gamma Co-60 with dry seed, 13% grain moisture and created at 25-30 krad. NPT3 is super rice varieties with characteristics such as: extremely short growing period (105-110 day crop; 130- 135 days in the spring, the average yield of 9-10 tones/ha), quality, stem, leaf stand, suitable for intensive capability, able to resist pests and unfavorable conditions especially the elements of productivity (amylase from 15-16%) and mass produced including hybrid rice as Nhi Uu 868, Thien Nguyen Uu 9, HYT100, etc. BQ rice varieties were high quality, average productivity gain of 7.5- 8.0 ton/ha, equivalent to hybrid rice, short growth period (105-110 days in summer season; 120- 130 days in spring season), and quality rice: content 18-20% amylose, rice delicious, supple as BC15. TQ14 varieties was planted in 2 seasons/ year, with agricultural and biological characteristics as Khang-Dan18 mutant with wide adaptation, high yield potential, the average gain from 5.9 to 6.2 tones/ha, short growth period (105-110 days in summer season, 130-135 days in spring season), insect resistance, quality of rice suitable for manufacturing technology like noodles, instant noodles, rice noodles, Ethanol. (author)

  4. A 16N gamma-ray facility

    Hull, Ethan L.; Pehl, Richard H.; Stanley, Michelle R.; Foster, Charles C.; Komisarcik, Kevin; East, Gary W.; Vanderwerp, John D.; Friesel, Dennis L.

    1997-02-01

    A practical 16N gamma-ray source is created in a medium-energy cyclotron environment. A 16N source emits 6129 and 7115 keV gamma rays. The viability of this several μCi source for detector calibration and studying detector physics is established.

  5. A 16N gamma-ray facility

    A practical 16N gamma-ray source is created in a medium-energy cyclotron environment. A 16N source emits 6129 and 7115 keV gamma rays. The viability of this several μCi source for detector calibration and studying detector physics is established. (orig.)

  6. Intercomparison of gamma ray analysis software packages

    The IAEA undertook an intercomparison exercise to review available software for gamma ray spectra analysis. This document describes the methods used in the intercomparison exercise, characterizes the software packages reviewed and presents the results obtained. Only direct results are given without any recommendation for a particular software or method for gamma ray spectra analysis

  7. Handbook on Mobile Gamma-ray Spectrometry

    Aage, Helle Karina; Korsbech, Uffe C C

    2003-01-01

    Basic physics and mathematics for Airborne and Car-borne Gamma-ray Spectrometry supplemented with practical examples and methods for advanced data processing......Basic physics and mathematics for Airborne and Car-borne Gamma-ray Spectrometry supplemented with practical examples and methods for advanced data processing...

  8. Sterilization of pharmaceuticals by gamma ray

    This paper shows the possibility of sterilization of certain pharmaceuticals and materials involved by gamma radiation from cobalt-60 and cesium-137 sources, and illustrates the importance of gamma ray sterilization compared with other sterilization methods. The paper also reviews some pharmaceuticals and materials involved, which proved the possibility of gamma ray sterilization. (author)

  9. Prompt gamma-ray activation analysis (PGAA)

    Kern, J. [Fribourg Univ. (Switzerland). Inst. de Physique

    1996-11-01

    The paper deals with a brief description of the principles of prompt gamma-ray activation analysis (PGAA), with the detection of gamma-rays, the PGAA project at SINQ and with the expected performances. 8 figs., 3 tabs., 10 refs.

  10. Gamma-ray pulsars: a gold mine

    Grenier, Isabelle A

    2015-01-01

    The most energetic neutron stars, powered by their rotation, are capable of producing pulsed radiation from the radio up to gamma rays with nearly TeV energies. These pulsars are part of the universe of energetic and powerful particle accelerators, using their uniquely fast rotation and formidable magnetic fields to accelerate particles to ultra-relativistic speed. The extreme properties of these stars provide an excellent testing ground, beyond Earth experience, for nuclear, gravitational, and quantum-electrodynamical physics. A wealth of gamma-ray pulsars has recently been discovered with the Fermi Gamma-Ray Space Telescope. The energetic gamma rays enable us to probe the magnetospheres of neutron stars and particle acceleration in this exotic environment. We review the latest developments in this field, beginning with a brief overview of the properties and mysteries of rotation-powered pulsars, and then discussing gamma-ray observations and magnetospheric models in more detail.

  11. Unveiling the Secrets of Gamma Ray Bursts

    Gomboc, A

    2012-01-01

    Gamma Ray Bursts (GRBs) are unpredictable and brief flashes of gamma rays that occur about once a day in random locations in the sky. Since gamma rays do not penetrate the Earth's atmosphere, they are detected by satellites, which automatically trigger ground-based telescopes for follow-up observations at longer wavelengths. In this introduction to Gamma Ray Bursts we review how building a multi-wavelength picture of these events has revealed that they are the most energetic explosions since the Big Bang and are connected with stellar deaths in other galaxies. However, in spite of exceptional observational and theoretical progress in the last 15 years, recent observations raise many questions which challenge our understanding of these elusive phenomena. Gamma Ray Bursts therefore remain one of the hottest topics in modern astrophysics.

  12. PEPIN, Methodology for Computing Concentrations, Activities, Gamma-Ray Spectra, and Residual Heat from Fission Products

    1 - Description of program or function: The concentrations, activities, gamma-ray spectra and residual heat from fission products can be calculated as a function of time for instantaneous fission or for one or more irradiation steps. 2 - Methods: Using the basic data in the libraries, the PEPIN code solves the differential equations satisfied by the fission product concentrations. Data Libraries: Independent Yields Library: 8 independent yields for 235U, 238U, 239U, 232U, 233U. Chain library: Precursor chain file for 635 nuclides. Gamma-Ray Energies Library: Average beta and gamma-ray energies in increasing order. 3 - Restrictions on the complexity of the problem: The number of nuclides must not exceed 650. The number of Gamma-Rays must not exceed 8500. The number of decay times must not exceed 59. The number of irradiation steps must not exceed 40

  13. Experimental Measurements and Computer Simulation of Fission Product Gamma-Ray Spectra

    Sanderson, D.C.W; Cresswell, A.; Allyson, J.D.; McConville, P.

    1997-01-01

    Airborne gamma ray spectrometry using high volume scintillation detectors, optionally in conjunction with Ge detectors, has potential for making rapid environmental measurements in response to nuclear accidents. An experimental investigation and computer simulation have been used to characterise the response of such detectors to short lived fission products. Small samples of 235U were irradiated in a research reactor for short periods, to generate fission product sources. Gamma ray spectra w...

  14. Gamma-ray effect on the leaf bud growth in peach

    The semilethal and lethal gamma-ray doses in irradiating peach leaf buds with regard to the application of experimental mutagenesis in peach tree have been determined. Peach scions have been gamma-irradiated in July, August and September at 1, 2, 3, 4. 5 and 6 kR. It is established that the amount of survived leaf bud grafts linearly declines as the irradiation dose rises. The semilethal dose LD50 for leaf buds varies in different years within the 2.7 to 4 kR range. The lethal dose in irradiated with 60Co gamma-rays peach leaf buds - is about 6 kR. (author)

  15. Modeling gamma-ray bursts

    Maxham, Amanda

    Discovered serendipitously in the late 1960s, gamma-ray bursts (GRBs) are huge explosions of energy that happen at cosmological distances. They provide a grand physical playground to those who study them, from relativistic effects such as beaming, jets, shocks and blastwaves to radiation mechanisms such as synchrotron radiation to galatic and stellar populations and history. Through the Swift and Fermi space telescopes dedicated to observing GRBs over a wide range of energies (from keV to GeV), combined with accurate pinpointing that allows ground based follow-up observations in the optical, infrared and radio, a rich tapestry of GRB observations has emerged. The general picture is of a mysterious central engine (CE) probably composed of a black hole or neutron star that ejects relativistic shells of matter into intense magnetic fields. These shells collide and combine, releasing energy in "internal shocks" accounting for the prompt emission and flaring we see and the "external shock" or plowing of the first blastwave into the ambient surrounding medium has well-explained the afterglow radiation. We have developed a shell model code to address the question of how X-ray flares are produced within the framework of the internal shock model. The shell model creates randomized GRB explosions from a central engine with multiple shells and follows those shells as they collide, merge and spread, producing prompt emission and X-ray flares. We have also included a blastwave model, which can constrain X-ray flares and explain the origin of high energy (GeV) emission seen by the Fermi telescope. Evidence suggests that gamma-ray prompt emission and X-ray flares share a common origin and that at least some flares can only be explained by long-lasting central engine activity. We pay special attention to the time history of central engine activity, internal shocks, and observed flares. We calculate the gamma-ray (Swift/BAT band) and X-ray (Swift/XRT band) lightcurves for arbitrary

  16. Software tool for xenon gamma-ray spectrometer control

    Chernysheva, I. V.; Novikov, A. S.; Shustov, A. E.; Dmitrenko, V. V.; Pyae Nyein, Sone; Petrenko, D.; Ulin, S. E.; Uteshev, Z. M.; Vlasik, K. F.

    2016-02-01

    Software tool "Acquisition and processing of gamma-ray spectra" for xenon gamma-ray spectrometers control was developed. It supports the multi-windows interface. Software tool has the possibilities for acquisition of gamma-ray spectra from xenon gamma-ray detector via USB or RS-485 interfaces, directly or via TCP-IP protocol, energy calibration of gamma-ray spectra, saving gamma-ray spectra on a disk.

  17. Gamma-ray Astronomy and GLAST

    McEnery, Julie

    2007-01-01

    The high energy gamma-ray (30 MeV to 100 GeV) sky has been relatively poorly studied. Most of our current knowledge comes from observations made by the Energetic Gamma Ray Experiment Telescope (EGRET) detector on the Compton Gamma Ray Observatory (CGRO), which revealed that the GeV gamma-ray sky is rich and vibrant. Studies of astrophysical objects at GeV energies are interesting for several reasons: The high energy gamma-rays are often produced by a different physical process than the better studied X-ray and optical emission, thus providing a unique information for understanding these sources. Production of such high-energy photons requires that charged particles are accelerated to equally high energies, or much greater. Thus gamma-ray astronomy is the study of extreme environments, with natural and fundamental connections to cosmic-ray and neutrino astrophysics. The launch of GLAST in 2008 will herald a watershed in our understanding of the high energy gamma-ray sky, providing dramatic improvements in sensitivity, angular resolution and energy range. GLAST will open a new avenue to study our Universe as well as to answer scientific questions EGRET observations have raised. In this talk, I will describe the GLAST instruments and capabilities and highlight some of the science we expect to address.

  18. Gamma-Ray Burst Physics with GLAST

    Omodei, N.; /INFN, Pisa

    2006-10-06

    The Gamma-ray Large Area Space Telescope (GLAST) is an international space mission that will study the cosmos in the energy range 10 keV-300 GeV, the upper end of which is one of the last poorly observed region of the celestial electromagnetic spectrum. The ancestor of the GLAST/LAT was the Energetic Gamma Ray Experiment Telescope (EGRET) detector, which flew onboard the Compton Gamma Ray Observatory (CGRO). The amount of information and the step forward that the high energy astrophysics made thanks to its 9 years of observations are impressive. Nevertheless, EGRET uncovered the tip of the iceberg, raising many questions, and it is in the light of EGRET's results that the great potential of the next generation gamma-ray telescope can be appreciated. GLAST will have an imaging gamma-ray telescope, the Large Area Telescope (LAT) vastly more capable than instruments own previously, as well as a secondary instrument, the GLAST Bursts Monitor, or GBM, to augment the study of gamma-ray bursts. Gamma-Ray Bursts (GRBs) science is one of the most exciting challenges for the GLAST mission, exploring the high energy emission of one of the most intense phenomena in the sky, shading light on various problems: from the acceleration of particles to the emission processes, to more exotic physics like Quantum Gravity effect. In this paper we report the work done so far in the simulation development as well as the study of the LAT sensitivity to GRB.

  19. Gamma-ray emission from globular clusters

    Tam, P H Thomas; Hui, C Y

    2012-01-01

    Over the last few years, the fruitful data provided by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope has revolutionized our understanding of high-energy processes in globular clusters, particularly those involving compact objects like millisecond pulsars (MSPs). Gamma-ray emission between 100 MeV to 10 GeV has been detected from more than a dozen globular clusters in our Galaxy, most notably 47 Tucanae and Terzan 5. Based on a sample of known gamma-ray globular clusters, empirical relations between the gamma-ray luminosity and properties of globular clusters such as stellar encounter rate, metallicity, as well as optical and infrared photon energy density in the cluster, have been derived. The gamma-ray spectra are generally described by a power law with a cut-off at a few GeV. Together with the detection of pulsed gamma-rays from a millisecond pulsar in a globular cluster, such spectral signature gives support that gamma-rays from globular clusters are collective curvature emission from...

  20. Responses of commercial broiler chicks to 60Co gamma-rays

    A total of 360 chicks of Nichols line at one-day old were used in this study. Within each sex, the chicks were divided into three exposure treatments (non-irradiated, 400 rads and 800 rads). The source of irradiation was 60Co gamma-rays. The results can be summarized as follows: Of the 360 chicks used in this study, only 10 chicks died during the experimental period. Radiation induced a reduction in body weight in both sexes during the growth period. Gamma-rays reduce the feed intake in both sexes. Moreover, the feed conversion ratio for the irradiated chicks was higher than that the non-irradiated birds. While red blood cells and hemoglobin content were higher in the irradiated chicks, white blood cells count and especially lymphocytes did not affect by 60Co gamma-rays. Gamma-rays had no effect on carcass, bone, meat and giblets as fractions of body weight in both sexes. Moreover, meat water content decreased and meat fat content increased in irradiated chicks. The total length and the total weight of the GI tract decreased due to 60Co gamma-rays. The response of the different regions of the GI tract to this rays is different. Moreover, the effect of this radiation on the GI tract is dependent upon the body weight irrespective of the sex. (orig./MG)

  1. Interaction between gamma rays and colchicine solution rice variety bengawan

    Seeds of rice variety Bengawan were radiated by gamma rays of different dosages (from 2.5 to 35 krad with interval of 2.5 krad). Half of each group of irradiated seeds were then treated with a 0.5% of colchicine solution for about 3 hours, 3 days after germination in petridishes. After being washed with distilled water the seedlings were planted in a nursery. One month old plants were then transplanted into polyethylene containers in the greenhouse. The seeds from the M-1 and M-2 plants were then cultivated in the field. Results of statis-tical calculation indicate that there is an interaction bet-ween gamma rays and colchicine solution treatments which affect the plant at dose level of 35 krad. The plant grows more erect, shorter, thicker, and resistent to lodging. (author)

  2. Gamma ray assisted fabrication of fluorescent oligographene nanoribbons

    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.

  3. Gamma-ray Burst Cosmology

    Wang, F Y; Liang, E W

    2015-01-01

    Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to $8.8\\times10^{54}$ erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the largest distances yet explored in the Universe. GRBs, as bright beacons in the deep Universe, would be the ideal tool to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal enrichment history of the Universe. In this article, we review the luminosity correlations of GRBs, and implications for constraining the cosmological parameters and dark energy. Observations show that the progenitors of long GRBs are massive stars. So it is expected that long GRBs are tracers of star formation rate. We also review the high-redshift star formation rate derived from GRBs, and implications for the cosmic reionization history. The afterglows of GRBs generally have broken power-law spectra, so it...

  4. Hygienizing with gamma rays for the treatment of sewage sludge

    This method which treats sewage sludge with gamma rays is supported by fundamental knowledge on the effects of ionizing rays on bacteria and parasites. This irradiation treatment neither increases the volume, nor does it release organic nitrogen compounds. The plant (designed for a flow rate of 30 m3/d, source distribution 105Ci60Co, 300 Krad) consists mainly of an irradiation shaft with a built-in central pipe and a circulation system with accessible pump shaft, circulation and suction pumps, block and regulating devices. (orig./HP)

  5. Effect of gamma-rays on corn grains. Pt. 1

    In order to study the effect of irradiation of corn grains on the starch extraction and quality of by-products, the grains were subjected to different doses of gamma-rays. It was generally found that irradiation led to increase the water absorption during steeping. This increase in the water absorption increases the yield of starch and facilitates the removal of hulls and germ. However, at higher dose (1,000 Krad) the yield of starch decreses. The results are discussed on the basis of effect of hydrogen bond protein denaturation, and formation of volatile compounds. (orig.)

  6. GAMMA-RAY AND X-RAY EMISSION FROM GAMMA-RAY-LOUD BLAZARS

    ZHANG XIONG; ZHAO GANG; XIE GUANG-ZHONG; ZHENG GUANG-SHENG; ZHANG LI

    2001-01-01

    We present a strong correlation of the gamma-ray (above 100 MeV) mean spectral indices aγ and X-ray (1 keV)mean spectral indices cX for 34 gamma-ray-loud blazars (16 BL Lac objects and 18 flat spectrum radio quasars). Astrong correlation is also found between the gamma-ray flux densities F-γ and X-ray flux densities Fx in the low state for 47 blazars (17 BL Lac and 30 flat spectrum radio quasars). Possible correlation on the gamma-ray emission mechanism is discussed. We suggest that the main gamma-ray radiation mechanism is probably the synchrotron process. The gamma-ray emission may be somewhat different from that of BL Lac objects and flat spectrum radio quasars.

  7. Determination of nitrogen in pork meat using in-vivo prompt gamma-ray activation technique

    The concentration of nitrogen in pork meat is determined by in-vivo prompt gamma-ray activation analysis using the reactor neutron beam and a high purity germanium gamma-ray spectrometer. The photopeak area of the 10827 keV high energy prompt gamma-ray, originated from 14N(n,γ) reaction on the pork medium, is analyzed to determine the concentration of nitrogen. Urea solutions with various concentration of nitrogen are used to calibrate the absolute efficiency of the gamma-ray spectrometer. In 9000 s irradiation and counting period, the minimum detectable concentration is 1.7 g of N/100 g of meat using the in-vivo technique. The result is also compared to data obtained by another analytical method. This nondestructive, in-vivo technique, with nominal radiation dose, is a reliable and promising method to determine the nitrogen concentration in living body. (author) 25 refs.; 2 figs

  8. Gamma-Ray Astrophysics NSSTC Fermi GBM

    National Aeronautics and Space Administration — The Fermi Gamma-Ray Burst Monitor (GBM) is not a pointed or imaging instrument. To determine fluxes for known sources, we measure the change in the count rate...

  9. Gamma rays from clusters of galaxies

    Blasi, P; Brunetti, G; Blasi, Pasquale; Gabici, Stefano; Brunetti, Gianfranco

    2007-01-01

    Clusters of galaxies and the large scale filaments that connect neighboring clusters are expected to be sites of acceleration of charged particles and sources of non-thermal radiation from radio frequencies to gamma rays. Gamma rays are particularly interesting targets of investigation, since they may provide precious information on the nature and efficiency of the processes of acceleration and magnetic confinement of hadrons within clusters of galaxies. Here we review the status of viable scenarios that lead to the production of gamma rays from large scale structures and are compatible with the multifrequency observations that are already available. We also discuss the possibility of detection of gamma rays with space-borne telescopes such as GLAST and ground based Cherenkov telescopes, and the physical information that may be gathered from such observations.

  10. Precision measurements of gamma-ray intensities

    To determine relative intensities of gamma rays in the region of 280 to 2750 keV, Ge(Li) detectors were calibrated with standard sources and cascade gamma-ray sources. Decay rates of the standard sources were determined by means of the 4πβ-γ or 4πX-γ coincidence method. Experimental conditions were improved and spectra were carefully analyzed. Relative gamma-ray intensities of 56Co, 88Y, sup(110m)Ag, 133Ba, 134Cs, 152Eu, 154Eu, 192Ir and 207Bi were determined within the accuracy of about 0.5% for strong gamma rays. Intensities per decays were obtained from the relative intensities for most of the nuclides. (author)

  11. Gamma-Ray Interactions for Reachback Analysts

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, Steven Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-02

    This presentation is a part of the DHS LSS spectroscopy training course and presents an overview of the following concepts: identification and measurement of gamma rays; use of gamma counts and energies in research.

  12. Gamma-ray detected radio galaxies

    Beckmann, Volker; Soldi, Simona; De Jong, Sandra; Kretschmer, Karsten; Savchenko, Volodymyr

    2016-07-01

    So far 15 radio galaxies have been detected in the gamma-ray domain by CGRO/EGRET and Fermi/LAT, with a few detections also in the VHE range. We search for distinguishing parameters and estimate the total number of gamma-ray emitting radio galaxies that are potentially detectable by Fermi/LAT. We use Fermi/LAT data in comparison with X-ray and hard X-ray data in order to constrain basic parameters such as the total power of the inverse Compton branch and the position of its peak. We search for possible correlations between the radio, UV, X-ray, and gamma-ray domain and derive the number counts distribution. We then compare their properties with those of the radio galaxies in the 3CRR and SMS4 catalogues. The data show no correlation between the peak of the inverse Compton emission and its luminosity. For the gamma-ray detected radio galaxies the luminosities in the various bands are correlated, except for the UV band, but there is no indication of a correlation of peak frequency or luminosity with the spectral slopes in the X-ray or gamma-ray band. The comparison with other bright radio galaxies shows that the gamma-ray detected objects are among those that have the largest X-ray but rather moderate radio fluxes. Their UV and X-ray luminosities are similar, but gamma-ray detected radio galaxies are predominantly of type FR-I, while the 3CRR sample contains mainly FR-II objects. The number counts of the so far gamma-ray detected radio galaxies shows a very shallow slope, indicating that potentially a fraction of radio galaxies has been missed so far or has not been identified as such, although the predicted number of 22 ± 7 is consistent with the observed 15 objects.

  13. Supernovae and gamma-ray bursts connection

    Valle, Massimo Della [INAF-Napoli, Capodimonte Observatory, Salita Moiariello, 16, I-80131 Napoli (Italy); International Center for Relativistic Astrophysics Network, Piazzale della Repubblica 10, I-65122, Pescara (Italy)

    2015-12-17

    I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

  14. Supernovae and gamma-ray bursts connection

    Valle, Massimo Della

    2015-12-01

    I'll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ˜ 0.4% - 3%.

  15. Studies on overcoming incompatibility of distant hybridization by gamma rays

    Distant hybridization was carried out after megagametes of hexaploid triticale 'Heizha 266' and androgametes of wheat varieties 'Longfu 30138', 'Longmai 11' and 'Longfu 10271' were irradiated with 60Co gamma rays from 600 to 1600 rad. Through the observation of the pollination in cut sections, it was found that 60-70 percent of embryo sacs were disintegrated 6 hours after pollination. The results of the investigations showed that the rate of fertilization were significantly increased by the irradiation. However, it was decreased with the increase in the dose of the irradiation. The radio-sensitivity of different wheat varieties varies greatly. The optimum dose of the irradiation was 600 rad for megagametes, and 800 rad for androgametes. The rate of survival for hybrid seeds was obviously increased by the treatment of the irradiation. By using tissue culture, some plants could be obtained from hybrids with embryo only

  16. Treatment of peach seeds with 60Co gamma-rays

    Peach seeds have been treated with gamma-rays during their stratification in February, March and early April to determine the optimal and lethal doses of irradiation. The latter took place at an intensity ranging between 1386 to 1750 r/min in doses of 4, 8, 12, 16, 20 and 24 kR. Untreated seeds have been used for control. The lethal dose (LD100) in irradiation stratified seeds in February and March prove to be about 16 kR. A dose between 4 to 8 kR is found most favourable for irradiation of stratified peach seeds. With raising the doses of irradiation the number of obtained plants declines. The mean height of plants also declines in the initial growth period. Some morphological changes such as shortened internodes, modified leaf shape and size, chlorophyll insufficiency and stopping of growth appear in some plants developing from irradiated seeds. (author)

  17. The HAWC Gamma-Ray Observatory: Sensitivity to Steady and Transient Sources of Gamma Rays

    Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fernandez, A; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, L X; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; Marinelli, A; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nava, J; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Salazar, H; Salesa, F; Sanchez, F E; Sandoval, A; Santos, E; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Sparks, K; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H

    2013-01-01

    The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is designed to record air showers produced by cosmic rays and gamma rays between 100 GeV and 100 TeV. Because of its large field of view and high livetime, HAWC is well-suited to measure gamma rays from extended sources, diffuse emission, and transient sources. We describe the sensitivity of HAWC to emission from the extended Cygnus region as well as other types of galactic diffuse emission; searches for flares from gamma-ray bursts and active galactic nuclei; and the first measurement of the Crab Nebula with HAWC-30.

  18. Cosmic gamma-ray studies at Srinagar

    Cosmic gamma ray studies being carried out at the Nuclear Research Laboratory at Srinagar and Gulmarg are described and some of the results of observation and possible conclusions are mentioned. These studies use ground base techniques which can detect short-time scale gamma ray bursts from supernovae and primordial black hole (PBH) and also high energy gamma rays from various point sources. A large area photomultiplier system is employed to detect pulses of visible fluorescence radiation which is caused by a gamma ray burst of supernovae of PBH origin. However, any signal out a large number of signals recorded at Gulmarg could not be identified as coinciding with any such event observed elsewhere. It shows that the size of the burst source cannot exceed 30 km., which is in agreement with neutron-star source models. An array using plastic scintillator detectors at the corner of a 10 metre square has been set up at Gulmarg to detect air-shower due to high energy gamma rays. Cerenkov light pulses recorded at Gulmarg have been projected on the sidereal map. A significant excess observed in the right ascension range 20 +- 3 h suggests the possible presence of a quasic-periodic source of gamma rays of energy greater than 1014 eV in the general direction of Cygnus X-3. Future programme of studies is mentioned. (K.M.)

  19. Gamma-ray Albedo of the Moon

    Moskalenko, Igor V.; Porter, Troy A.

    2007-06-14

    We use the GEANT4 Monte Carlo framework to calculate the gamma-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of gamma-rays from the Moon is very steep with an effective cutoff around 3 GeV (600 MeV for the inner part of the Moon disc). Since it is the only (almost) black spot in the gamma-ray sky, it provides a unique opportunity for calibration of gamma-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The albedo flux depends on the incident CR spectrum which changes over the solar cycle. Therefore, it is possible to monitor the CR spectrum using the albedo gamma-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo -rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the GLAST LAT to monitor the CR spectrum near the Earth beyond the lifetime of PAMELA.

  20. Gamma rays from extragalactic astrophysical sources

    Bosch-Ramon, V

    2011-01-01

    Presently there are several classes of detected gamma-ray extragalatic sources. They are mostly associated to active galactic nuclei (AGN) and (at soft gamma rays) to gamma-ray bursts (GRB), but not only. Active galactic nuclei consist of accreting supermassive black holes hosted by a galaxy that present in some cases powerful relativistic jet activity. These sources, which have been studied in gamma rays for several decades, are probably the most energetic astrophysical objects, and their appearance depends much on whether their jets point to us. Gamma-ray bursts, thought to be associated to collapsing or merging stellar-mass objects at cosmological distances, are also accreting highly relativistic jet sources that shine strongly at high energies. These are very short-duration events, but they are also the most luminous. Recently, star formation galaxies have turned out to be also gamma-ray emitters. On the other hand, clusters of galaxies have not been detected beyond X-rays yet. These are the largest known...

  1. Gamma-Ray Bursts: The End Game

    Lamb, Don

    1997-11-01

    The nature of gamma-ray bursts has been one of the greatest unsolved mysteries in astrophysics for more than a quarter century. A major reason for this is that no definite counterparts to the bursts could be found at other wavelengths, despite intense efforts spanning more than two decades. Consequently, the study of gamma-ray bursts has been isolated from the rest of astronomy. Scientists studying them have had only the laws of physics and the bursts themselves to guide them in attempting to solve the burst mystery. All of this changed dramatically with the discovery earlier this year of fading X-ray and optical sources in the arcminute-sized positional error boxes of several gamma-ray bursts. For the first time, temporal, as well as spatial, coincidence could be used to associate these X-ray and optical sources with the gamma-ray bursts. As a result, the odds are great that the fading X-ray and optical sources are counterparts of the bursts, and that the study of gamma-ray bursts has finally been connected with the rest of astronomy. In this talk, we describe the dramatic new information about the nature of gamma-ray bursts that the X-ray, optical, and radio observations of the fading sources have provided, and emphasize the implications that this information has for the distance scale to the bursts.

  2. Gamma-ray pulsar studies with COMPTEL

    Hermsen, W.; Kuiper, L.; Diehl, R.; Lichti, G.; Schoenfelder, V.; Strong, A. W.; Connors, A.; Ryan, J.; Bennett, K.; Busetta, M.; Carraminana, A.; Buccheri, R.; Grenier, I. A.

    1994-06-01

    Since the launch of the Compton Gamma-Ray Observatory (CGRO) the number of detected gamma-ray pulsars increased from two to six. COMPTEL, on-board CGRO and sensitive to gamma-rays with energies between approximately 0.7 and 30 MeV, detected three of these unambiguously. The classical Crab and Vela pulsars have been observed on several occasions and detailed pulse patterns and spectral parameters have been derived. The new CGRO gamma-ray pulsar PSR B1509-58 has been detected by COMPTEL at a significance level above 4 sigma, consistently in a timing and spatial analysis. A likely detection of Geminga has been obtained at an approximately 3 sigma level. This indication is found in a phase interval in which COS B data showed the presence of a new variable component, Interpeak 2, exhibiting a very soft spectrum above 50 MeV. The diversities in light-curve sphapes and spectral distributions, the apparent time variabilities, and the significant differences in the fractions of the spin-down power radiated at gamma-ray energies in this small sample of gamma-ray pulsars pose important constraints to pulsar modeling.

  3. Zinc oxide nanowire gamma ray detector with high spatiotemporal resolution

    Mayo, Daniel C.; Nolen, J. Ryan; Cook, Andrew; Mu, Richard R.; Haglund, Richard F.

    2016-03-01

    Conventional scintillation detectors are typically single crystals of heavy-metal oxides or halides doped with rare-earth ions that record the recombination of electron-hole pairs by photon emission in the visible to ultraviolet. However, the light yields are typically low enough to require photomultiplier detection with the attendant instrumental complications. Here we report initial studies of gamma ray detection by zinc oxide (ZnO) nanowires, grown by vapor-solid deposition. The nanowires grow along the c-axis in a wurtzite structure; they are typically 80 nm in diameter and have lengths of 1- 2 μm. The nanowires are single crystals of high quality, with a photoluminescence (PL) yield from band-edge exciton emission in the ultraviolet that is typically one hundred times larger than the PL yield from defect centers in the visible. Nanowire ensembles were irradiated by 662 keV gamma rays from a Cs-137 source for periods of up to ten hours; gamma rays in this energy range interact by Compton scattering, which in ZnO creates F+ centers that relax to form singly-charged positive oxygen vacancies. Following irradiation, we fit the PL spectra of the visible emission with a sum of Gaussians at the energies of the known defects. We find highly efficient PL from the irradiated area, with a figure of merit approaching 106 photons/s/MeV of deposited energy. Over a period of days, the singly charged O+ vacancies relax to the more stable doubly charged O++ vacancies. However, the overall defect PL returns to pre-irradiation values after about a week, as the vacancies diffuse to the surface of these very thin nanowires, indicating that a self-healing process restores the nanowires to their original state.

  4. Phytonutrient analysis of gamma rays mutated tomato

    Full text: With increasing of world population and reducing land resources, good quality food production has become even more important. Mutant breeding is an inevitable way for producing of vegetable crops which are sustainable under varied agro-climatic conditions and have high nutrient capacity. The use of nuclear techniques in plant breeding has been mostly directed for inducing mutations. Since the use of ionizing radiation, such as X-rays, gamma rays, e-beam and neutrons for inducing variation, has become an established technology. Induced mutations have been used in the economic value improvement of major crops such as cereals and solanaceae, which are seed propagated. The economic value of a new variety can be assessed from several parameters. From these not only area planted to the variety and percentage of the area under the crop in the region, increased yield and savings in water but also increased nutritive value, and enhanced quality are also very important parameters which should have taken into consideration. Often, induced mutations lead to more advantages than a simple desired phenotypic change.In this study, tomato seeds were irradiated at the dose of 150 Gy by using 60Co gamma rays irradiator at a fixed dose rate of 0.654 kGy/h. These seeds were planted and M4 stage mutant lines were analysed for phytonutrient capacity by using HPLC system with different types of detectors depending on the analytes to be determined (vitamin C, carotenoids and vitamin E). Accelerated Solvent Extraction technique was used for the extraction of vitamin C from the samples under high pressure of nitrogen gas. For carotenoids and tocopherols extractions, liquid-liquid partition technique was used. Photodiode Array, UV and Fluorescence detectors were used for the determination of vitamin C (L-ascorbic acid), some carotenoids (lutein, β-carotene, lycopene) and vitamin E ( α-, γ-, δ tocopherols), respectively. Results obtained from these analysis were found as follows

  5. Contribution of External Gamma Rays to SPND at HANARO

    Park, B. G.; Cho, D. K.; Kim, M. S.; Kang, G. D. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Self-Powered Neutron Detectors (SPNDs) have been widely used for monitoring the neutron flux in reactors as well as in irradiation facilities. In its simplest form, the detector operates on the basis of directly measuring the beta decay current following neutron capture. The neutron capture cross-section of {sup 103}Rh, which is used for an emitter of the SPND, is 142.13 barns for thermal neutron (0.0253 eV). After neuron capture of {sup 103}Rh, the compound nuclei of {sup 104}Rh (92.6%) and {sup 104}mRh (7.4%) are produced. The sensitivity of SPND is generally defined as. The influence of water in the irradiation basket on the external gamma rays is determined by calculations of neutron capture reaction and photon interaction rates at various irradiation positions in HANARO. Since it is not easy to correct the contribution of the external gamma rays to the current signal by measurements at the research reactor, it is advantageous to reduce materials such as water at the irradiation position.

  6. Effects of neutrons and gamma-rays on polymethylmethacrylate plastic optical fiber

    Toh, K., E-mail: toh.kentaro@jaea.go.jp [J-PARC Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); Sakasai, K.; Nakamura, T.; Soyama, K. [J-PARC Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); Shikama, T. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2011-10-01

    The effects of neutron and gamma-ray irradiation on a polymethylmethacrylate (PMMA) plastic optical fiber (POF) were investigated. An improvement in the optical transmission was observed at the beginning of irradiation, but radiation damage (radiation-induced transmission loss in the visible wavelength range) increased as the irradiation continued. To determine the effects of neutrons and gamma-rays, the amount of energy absorbed in the PMMA POF was calculated using the PHITS codes. Energy deposition in the fiber was calculated considering nuclear reactions listed in the nuclear data file used for the Monte Carlo N-particle transport code. The effects of neutron and gamma radiation were observed to be similar with absorbed energy less than 1.2 kGy. However, the transmission loss induced by neutrons was larger than that induced by gamma-rays when higher energy was deposited.

  7. New insights from cosmic gamma rays

    Roland, Diehl

    2016-04-01

    The measurement of gamma rays from cosmic sources at ~MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace nuclear processes most directly, as they originate from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this astronomical window and is discussed here: Cosmic positrons are often produced from β-decays, thus also of nuclear physics origins. The nuclear reactions leading to radioactive isotopes occur inside stars and stellar explosions, which therefore constitute the main objects of such studies. In recent years, both thermonuclear and core-collapse supernova radioactivities have been measured though 56Ni, 56Co, and 44Ti lines, and a beginning has thus been made to complement conventional supernova observations with such measurements of the prime energy sources of supernova light created in their deep interiors. The diffuse radioactive afterglow of massive-star nucleosynthesis in gamma rays is now being exploited towards astrophysical studies on how massive stars feed back their energy and ejecta into interstellar gas, as part of the cosmic cycle of matter through generations of stars enriching the interstellar gas and stars with metals. Large interstellar cavities and superbubbles have been recognised to be the dominating structures where new massive-star ejecta are injected, from 26Al gamma-ray spectroscopy. Also, constraints on the complex interiors of stars derive from the ratio of 60Fe/26Al gamma rays. Finally, the puzzling bulge-dominated intensity distribution of positron annihilation gamma rays is measured in greater detail, but still not understood; a recent microquasar flare provided evidence that such objects may be prime sources for positrons in interstellar space, rather than

  8. Application of Laser Compton Scattered gamma-ray beams to nondestructive detection and assay of nuclear material

    Generation of energy-tunable gamma-rays via Laser Compton Scattering (LCS) is of great interest for scientific studies and applications of MeV photons which interact with nuclei. One of the promising applications of such energy-tunable gamma-rays is the non-destructive detection and assay of nuclides which are necessary for nuclear security and safeguards. Utilizing this LCS gamma-ray beam in combination with nuclear resonant fluorescence (NRF), we can make non-destructive measurement of arbitrary nuclides. The principle of LCS-NRF is as follows. When a nucleus is irradiated by a gamma-ray and when the energy of the gamma ray is identical to the transition energy from the ground state of the nucleus, the incident gamma-ray is absorbed by the nucleus, and subsequently the nucleus de-excites by gamma-ray emission. Since the energies of the state excited by NRF are inherent in the atomic number and mass of the nucleus of interest, detection and assay of nuclides are possible by NRF measurement. The ability of gamma-ray beams to penetrate a sample enables us to detect or assay specific nuclides even inside a sample. We are developing a high-flux and a high-brightness gamma-ray source based on an energy-recovery linac and a laser enhancement cavity to produce a gamma-ray beam of 1013 ph/s. Gamma-ray measurement methods optimized for highly radioactive samples are also under development. (A.C.)

  9. Fermi LAT Discovery of Extended Gamma-Ray Emissions in the Vicinity of the HB3 Supernova Remnant

    Katagiri, H; Ballet, J; Grondin, M H; Hanabata, Y; Hewitt, J W; Kubo, H; Lemoine-Goumard, M

    2016-01-01

    We report the discovery of extended gamma-ray emission measured by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) HB3 (G132.7+1.3) and the W3 HII complex adjacent to the southeast of the remnant. W3 is spatially associated with bright 12CO (J=1-0) emission. The gamma-ray emission is spatially correlated with this gas and the SNR. We discuss the possibility that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray emission. The emission from W3 is consistent with irradiation of the CO clouds by the cosmic rays accelerated in HB3.

  10. Gamma-Ray Lenses for Astrophysics-and the Gamma-Ray Imager Mission GRI

    Wunderer, C. B.; Ballmoos, P. V.; Barriere, N.;

    2009-01-01

    , albeit at much more modest sensitivities. There will be clearly a growing need to perform deeper, more focused investigations of gamma-ray sources in the 100-keV to MeV regime. Recent technological advances in the domain of gamma-ray focusing using Lane diffraction and multilayer-coated mirror techniques......Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are...... accelerated to extreme relativistic energies by mechanisms which are still poorly understood, and nuclear reactions are synthesizing the basic constituents of our world. Cosmic accelerators and cosmic explosions are major science themes that are addressed in the gamma-ray regime. While Fermi will take the...

  11. Optimizing the method of gamma ray treatment of sewage sludges

    Since 1973, the municipality of Geiselbullach near Munich operates a gamma source for sewage sludge disinfection. The contribution in hand first deals with the reasons calling for sewage sludge disinfection, and then discusses the efficiency of gamma radiation for this purpose. Technical details are given, and chances of improvement with regard to process engineering and operation are discussed on the basis of operating experience. Economic aspects are discussed of ordinary gamma ray treatment and of a combined method also using oxi-irradiation. (DG)

  12. Stellar Photon Archaeology with Gamma-Rays

    Stecker, Floyd W.

    2009-01-01

    Ongoing deep surveys of galaxy luminosity distribution functions, spectral energy distributions and backwards evolution models of star formation rates can be used to calculate the past history of intergalactic photon densities and, from them, the present and past optical depth of the Universe to gamma-rays from pair production interactions with these photons. The energy-redshift dependence of the optical depth of the Universe to gamma-rays has become known as the Fazio-Stecker relation (Fazio & Stecker 1970). Stecker, Malkan & Scully have calculated the densities of intergalactic background light (IBL) photons of energies from 0.03 eV to the Lyman limit at 13.6 eV and for 0$ < z < $6, using deep survey galaxy observations from Spitzer, Hubble and GALEX and have consequently predicted spectral absorption features for extragalactic gamma-ray sources. This procedure can also be reversed. Determining the cutoff energies of gamma-ray sources with known redshifts using the recently launched Fermi gamma-ray space telescope may enable a more precise determination of the IBL photon densities in the past, i.e., the "archaeo-IBL.", and therefore allow a better measure of the past history of the total star formation rate, including that from galaxies too faint to be observed.

  13. GRI: the gamma-ray imager mission

    Knödlseder, J

    2006-01-01

    Observations of the gamma-ray sky reveal the most powerful sources and the most violent events in the Universe. While at lower wavebands the observed emission is generally dominated by thermal processes, the gamma-ray sky provides us with a view on the non-thermal Universe. Here particles are accelerated to extreme relativistic energies by mechanisms which are still poorly understood, and nuclear reactions are synthesizing the basic constituents of our world. Cosmic accelerators and cosmic explosions are the major science themes that are addressed in the gamma-ray regime. With the INTEGRAL observatory, ESA has provided a unique tool to the astronomical community revealing hundreds of sources, new classes of objects, extraordinary views of antimatter annihilation in our Galaxy, and fingerprints of recent nucleosynthesis processes. While INTEGRAL provides the global overview over the soft gamma-ray sky, there is a growing need to perform deeper, more focused investigations of gamma-ray sources. In soft X-rays a...

  14. Gamma-ray binaries and related systems

    Dubus, Guillaume

    2013-01-01

    After initial claims and a long hiatus, it is now established that several binary stars emit high (0.1-100 GeV) and very high energy (>100 GeV) gamma rays. A new class has emerged called 'gamma-ray binaries', since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary (eta Car) have also been detected - 'related systems' that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common ? What drives their high-energy emission ? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants ? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as ...

  15. Status of the Milagro Gamma Ray Observatory

    Maryland Univ. College Park

    2001-01-01

    The Milagro Gamma Ray Observatory, located at an altitude of 8,600 feet in the Jemez Mountains of New Mexico, is the world's first large-area water Cherenkov detector capable of continuously monitoring the entire sky for sources of TeV gamma rays. It is uniquely capable of searching for transient sources of VHE gamma rays. The core of the detector is a 60m x 80m x 8m pond instrumented with 723 PMTs deployed in two layers. This part of the detector is complete and has operated continuously since Jan. 2000. Initial studies including searches for gamma-ray sources are ongoing, and preliminary results are available. The final stage of construction is under way. We are deploying 170 auxiliary "outrigger" water Cherenkov detectors in an area of 40,000 square-meters surrounding the pond, which will significantly enhance our ability to reject background and more accurately reconstruct the gamma-ray direction and energy. In addition, we are lowering the energy threshold of the detector by using custom processing to en...

  16. Transuranic isotopic analysis using gamma rays

    Clark, D; Decman, D

    1998-10-15

    Transuranic waste typically emits gamma rays that are characteristic of the isotopic composition of the materials. If the area of the gamma ray photopeaks in a High Purity Ge (HPGe) spectrum can be accurately determined and if the gamma ray/x-ray branching ratios and half-lives for the radionuclides in the sample are known the relative concentration of each isotope in the waste can be determined using tomographic techniques. Methods used to accurately determine these photopeaks usually requires a computer code that does multi-peak analysis and unfolding of a given part of the gamma-ray spectrum. Computer techniques allow an accurate determination of the photopeaks and hence the isotopic composition of the waste material. These computer techniques can be automated for different spectra within a wide range of possible isotopic compositions. To improve photopeak statistics all of the spectra taken in a tomographic survey of the sample are summed and are used in the isotopic analysis. The method, accuracy, and limitations of this type of isotopic analysis system will be discussed. The gamma ray acquisition system is currently being upgraded with multiple HPGe detectors to improve the counting statistics obtainable in a given amount of time. The results of the DOE performance evaluations and the progress of the multiple detector upgrade will be discussed.

  17. Gamma-Ray Astronomy from the Ground

    Horns, D

    2016-01-01

    The observation of cosmic gamma-rays from the ground is based upon the detection of gamma-ray initiated air showers. At energies between approximately $10^{11}$ eV and $10^{13}$ eV, the imaging air Cherenkov technique is a particularly successful approach to observe gamma-ray sources with energy fluxes as low as $\\approx 10^{-13}$ erg\\,cm$^{-2}\\,$s$^{-1}$. The observations of gamma-rays in this energy band probe particle acceleration in astrophysical plasma conditions and are sensitive to high energy phenomena beyond the standard model of particle physics (e.g., self-annihilating or decaying dark matter, violation of Lorentz invariance, mixing of photons with light pseudo-scalars). The current standing of the field and its major instruments are summarised briefly by presenting selected highlights. A new generation of ground based gamma-ray instruments is currently under development. The perspectives and opportunities of these future facilities will be discussed.

  18. A Search for Gamma-Ray Bursts and Pulsars, and the Application of Kalman Filters to Gamma-Ray Reconstruction

    Jones, B B

    2002-01-01

    Part I describes the analysis of periodic and transient signals in EGRET data. A method to search for the transient flux from gamma-ray bursts independent of triggers from other gamma-ray instruments is developed. Several known gamma-ray bursts were independently detected, and there is evidence for a previously unknown gamma-ray burst candidate. Statistical methods using maximum likelihood and Bayesian inference are developed and implemented to extract periodic signals from gamma-ray sources ...

  19. Gamma-ray- and fission-neutron-induced micronuclei in PHA-stimulated and unstimulated human lymphocytes

    Two groups of normal human an blood cells, one stimulated with phytohaemagglutinin (PHA) for 24 hr (G1-S phase of the cell cycle) and one unstimulated (G0 phase), were irradiated with 60Co gamma rays or 252Cf radiation. A comparison of radiation-induced micronucleus frequencies showed that the high-dose-rate gamma rays were more effective in inducing micronuclei than were low-dose-rate gamma rays. In the cells exposed to low-dose-rate irradiation, there was little difference between the frequency of micronuclei in the G0 phase and the G1-S phase. However, cells in the G1-S phase were more sensitive than G0-phase cells to high-dose-rate gamma rays. The relative biological effectiveness of 252Cf neutron irradiation measured in micronucleus assays was consistent with the value obtained for the lethal effect of 252Cf on cultured cells. (author)

  20. Breeding high protein rice through the use of gamma rays

    In a programme designed for inducing and breeding high protein lines of rice (oryza sativa) through the use of gamma rays, seed lots of seven varieties and strains originated from japonica, indica and (japonica x indica) types were irradiated with 5, 10 and 15 krad of 60Co gamma rays and planted with their non-irradiated controls. Resulted seeds were transformed to M2 generation without selection. Dehusked M2 seeds were analysed for protein content by the use of Dye Binding Capacity (DBC). Results showed significant increases in the mean seed protein percentages of jap. types: Giza 170, Sabeeni and Strain H 230/106 in the 15 Kr treatments, and a decrease in the mean seed-protein content of the strain H 214/37 (10 Kr treatment). The mean seed-protein content of the hybrid strain H 236/9 was also increased by the 15 Kr treatment. The coefficient of values were increased in all of the irradiation treatments used which may provide possibilities for selecting rice of higher seed-protein content in latter generations

  1. The effects of gamma rays and genotypes on sunflower organogenesis traits [Helianthus annuus L.

    Seeds of two inbred lines (AS613 and AS616) and their hybrid were irradiated with seven gamma rays doses (5, 15, 25, 35, 45, 55 and 65 Grays). Organogenesis traits were studied for all irradiated seeds as well as non irradiated ones used as control. The experiment was designed as a randomized complete block with three replications. Each replication consisted of 16 Petri dishes with four explants per gamma rays dose and per genotype. The regeneration ability of genotypes and the effects of gamma rays on regeneration were scored by assessing the percentage of explants forming shoots (ES/100E), the average number of shoots per explant shooting (S/ES) and the average number of shoots per explant plated (S/E). Genetic variability was observed among the three genotypes for all studied traits. The effect of irradiation and the interaction between genotype and irradiation were also significant for all the studied traits. Heterosis, when the hybrid was compared with the mean of the two parents, was significant for the different gamma rays doses in all traits except for 15 and 55 Grays, which were not significant for the percentage of explants forming shoots (ES/100E). Seed irradiation by 5 and 15 Grays is likely to have a significant effect by increasing the regeneration ability by cotyledon culture in sunflower

  2. Effect of gamma-ray on olive fruits quality, enzyme activities and issued oil

    The results described in the present work concern the study of changes in gamma ray irradiated olive fruit (Tunisian variety: Chemlali) quality along the storage time processing and the quality of olive oil issued. The study focused on the changes related to the microbiological, physico-chemical properties, as well as pectinase activities in olive after irradiation. We also have been interested in the final product quality after oil extraction. The results of non irradiated olives were presented for comparative purposes. Mature olive fruits were treated with 0.5, 1 and 1.5 kGy gamma ray radiation. Olive fruits were then stored for one month. Irradiation at 1.5 kGy allows the almost total destruction of the total aerobic germs, yeasts and moulds. Concerning physico-chemical parameters, the increase of the dose level generated an improvement in water retention capacity and decreased the rate of polysaccharides hydrolyzes olives. Moreover, the irradiation dose of 0.5 kGy induced the increase in pectinase activities thanks to the improvement of the protein extraction yield. The gamma ray irradiation of olive fruit seems to not decrease olive oil oxidative stability in the studied samples. Finally, gamma ray radiation was able to improve the yield of extraction of the oil and insaponifiable fraction as polyphenols and beta carotenes. (Author)

  3. Heliospheric Origin of $\\gamma$-Ray Bursts

    Li Ti Pei

    1997-01-01

    Systematic variations of average observational characteristics and correlation properties between different parameters of gamma-ray bursts (GRBs) with time from 1991 April to 1994 September are revealed. It is hard to explain the observed long-term variability by variations of experimental conditions. The variability of GRB properties with the time scale of months to years, together with the similarity between GRBs, solar hard X-ray flares and terrestrial gamma-ray flashes, may indicate an origin of GRBs, at least partly, within the heliosphere. Large-voltage and high-temperature pinch plasma columns produced by disruptive electrical discharges in the outer heliosphere can generate hard X-ray and gamma-ray flashes with energy spectra and spectral evolution characters consistent with that observed in GRBs.

  4. Gamma Ray Astronomy with Magnetized Zevatrons

    Armengaud, E; Miniati, F; Armengaud, Eric; Sigl, Guenter; Miniati, Francesco

    2005-01-01

    Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV are produced in magnetized environments such as galaxy clusters, the flux of secondary gamma-rays below ~1 TeV can be enhanced up to several orders of magnitudes compared to unmagnetized sources. A particular source of enhancement are synchrotron and cascade photons from e^+e^- pairs produced by protons from sources with relatively steep injection spectra proportional to E^-2.6. Such sources should be visible at the same time in ultra-high energy cosmic ray experiments and gamma-ray telescopes.

  5. Technology Needs for Gamma Ray Astronomy

    Gehrels, Neil

    2011-01-01

    Gamma ray astronomy is currently in an exciting period of multiple missions and a wealth of data. Results from INTEGRAL, Fermi, AGILE, Suzaku and Swift are making large contributions to our knowledge of high energy processes in the universe. The advances are due to new detector and imaging technologies. The steps to date have been from scintillators to solid state detectors for sensors and from light buckets to coded aperture masks and pair telescopes for imagers. A key direction for the future is toward focusing telescopes pushing into the hard X-ray regime and Compton telescopes and pair telescopes with fine spatial resolution for medium and high energy gamma rays. These technologies will provide finer imaging of gamma-ray sources. Importantly, they will also enable large steps forward in sensitivity by reducing background.

  6. New insights from cosmic gamma rays

    Diehl, Roland

    2016-01-01

    The measurement of gamma rays from cosmic sources at MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace nuclear processes most directly, as they originate from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this astronomical window and is discussed here: Cosmic positrons are often produced from beta-decays, thus also of nuclear physics origins. The nuclear reactions leading to radioactive isotopes occur inside stars and stellar explosions, which therefore constitute the main objects of such studies. In recent years, both thermonuclear and core-collapse supernova radioactivities have been measured, and complement conventional supernova observations with measurements of their prime energy sources. The diffuse radioactive afterglow of massi...

  7. Librarian driven analysis of gamma ray spectra

    For a set of a priori given radionuclides extracted from a general nuclide data library, the authors use median estimates of the gamma-peak areas and estimates of their errors to produce a list of possible radionuclides matching gamma ray line(s). The identification of a given radionuclide is obtained by searching for a match with the energy information of a database. This procedure is performed in an interactive graphic mode by markers that superimpose, on the spectral data, the energy information and yields provided by a general gamma ray data library. This library of experimental data includes approximately 17,000 gamma ray energy lines related to 756 known gamma emitter radionuclides listed by the ICRP. (author)

  8. High Energy Radiation from $\\gamma$ Ray Bursts

    Dermer, C D; Dermer, Charles D.; Chiang, James

    1999-01-01

    Gamma-ray burst (GRB) engines are probed most intimately during the prompt gamma-ray luminous phase when the expanding blast wave is closest to the explosion center. Using GRBs 990123 and 940217 as guides, we briefly review observations of high-energy emission from GRBs and summarize some problems in GRB physics. \\gamma\\gamma transparency arguments imply relativistic beaming. The parameters that go into the external shock model are stated, and we show numerical simulation results of gamma-ray light curves from relativistic blast waves with different amounts of baryon loading. A distinct component due to the synchrotron self-Compton process produces significant emission at GeV and TeV energies. Predictions for spectral and temporal evolution at these energies are presented for a blast wave expanding into uniform surroundings. Observations of the slow decay of GeV-TeV radiation provide evidence for ultra-high energy cosmic ray acceleration in GRBs.

  9. Gamma-ray bursters at cosmological distances

    Paczynski, B.

    1986-01-01

    It is proposed that some, perhaps most, gamma-ray bursters are at cosmological distances, like quasars, with a redshift of about 1 or 2. This proposition requires a release of supernova-like energy of about 10 to the 51st ergs within less than 1 s, making gamma-ray bursters the brightest objects known in the universe, many orders of magnitude brighter than any quasars. This power must drive a highly relativistic outflow of electron-positron plasma and radiation from the source. It is proposed that three gamma-ray bursts, all with identical spectra, detected from B1900 + 14 by Mazets, Golenetskii, and Gur'yan and reported in 1979, were all due to a single event multiply imaged by a gravitational lens. The time intervals between the successive bursts, 10 hr to 3 days, were due to differences in the light travel time for different images.

  10. Evaluation of gamma-ray intensities

    Relative intensities and intensities per decay of gamma rays were evaluated for 16 nuclides, 22Na, 24Na, 46Sc, 54Mn, 60Co, 85Sr, 88Y, 95Nb, sup(108m)Ag, 134Cs, 133Ba, 139Ce, sup(180m)Hf, 198Au, 203Hg and 207Bi. For most of these nuclides disintegration rates can be determined by means of β-γ or X-γ coincidence method. Since decay schemes of these nuclides are established, intensities per decay of strong gamma rays were accurately evaluated by using weak beta-ray branching ratios, relative gamma-ray intensities and internal conversion coefficients. Half-lives of the nuclides were also evaluated. Use of the nuclides, therefore, are recommended for precision intensity calibration of the detectors. (author)

  11. Solution To The Gamma Ray Burst Mystery?

    Dar, Arnon

    1996-01-01

    Photoexcitation and ionization of partially ionized heavy atoms in highly relativistic flows by interstellar photons, followed by their reemission in radiative recombination and decay, boost star-light into beamed $\\gamma$ rays along the flow direction. Repeated excitation/decay of highly relativistic baryonic ejecta from merger or accretion induced collapse of neutron stars in dense stellar regions (DSRs), like galactic cores, globular clusters and super star-clusters, can convert enough kinetic energy in such events in distant galaxies into cosmological gamma ray bursts (GRBs). The model predicts remarkably well all the main observed temporal and spectral properties of GRBs. Its success strongly suggests that GRBs are $\\gamma$ ray tomography pictures of DSRs in galaxies at cosmological distances with unprecedented resolution: A time resolution of $dt\\sim 1~ms$ in a GRB can resolve stars at a Hubble distance which are separated by only $D\\sim 10^{10}cm$. This is equivalent to the resolving power of an optica...

  12. Influence of the irradiation by the {gamma} rays on various factors of immunity; Influence de l'irradiation par les rayons {gamma} sur divers facteurs d'immunite

    Gaude, G.; Coursaget, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Exposed animals often present, in the days or weeks following the irradiation, heavy infectious lesions. The goal of this survey was to search the influence of the total irradiation by the gamma radiation from cobalt-60, on the organism, on the phagocytic power of the leukocytes and on the biogenesis of antibodies. The experiences were done on hundred animals, rabbits and guinea pigs. All irradiations have been achieved with eight sources of Cobalt 60 of 10 curies each, disposed on a sphere of 1 m, the animal living the region neighboring of the center. The intensity of the radiation, in these conditions, is about 100 roentgens per hour. (authors) [French] Les animaux irradies presentent souvent, dans les jours ou les semaines qui suivent l'irradiation, de graves lesions infectieuses. Le but de cette etude etait de rechercher l'influence de l'irradiation totale de l'organisme par le rayonnement gamma du cobalt 60 sur le pouvoir phagocytaire des leucocytes et sur la biogenese des anticorps. Les experiences portent sur une centaine d'animaux, lapins et cobayes. Toutes les irradiations ont ete realisees avec huit sources de Cobalt 60 de 10 curies chacune, disposees sur une sphere de 1 m de rayon, les animaux ocoupant la region voisine du centre. L'intensite du rayonnement est, dans ces conditions, d'environ 100 roentgens par heure. (auteurs)

  13. Gamma Ray Bursts in the HAWC Era

    Mészáros, Peter; Murase, Kohta; Fox, Derek; Gao, He; Senno, Nicholas

    2015-01-01

    Gamma-Ray Bursts are the most energetic explosions in the Universe, and are among the most promising for detecting multiple non-electromagnetic signals, including cosmic rays, high energy neutrinos and gravitational waves. The multi-GeV to TeV gamma-ray range of GRB could have significant contributions from hadronic interactions, mixed with more conventional leptonic contributions. This energy range is important for probing the source physics, including overall energetics, the shock parameters and the Lorentz factor. We discuss some of the latest observational and theoretical developments in the field.

  14. Gamma-Ray Bursts: Jets and Energetics

    Frail, D A

    2003-01-01

    The relativistic outflows from gamma-ray bursts are now thought to be narrowly collimated into jets. After correcting for this jet geometry there is a remarkable constancy of both the energy radiated by the burst and the kinetic energy carried by the outflow. Gamma-ray bursts are still the most luminous explosions in the Universe, but they release energies that are comparable to supernovae. The diversity of cosmic explosions appears to be governed by the fraction of energy that is coupled to ultra-relativistic ejecta.

  15. Gamma Ray Astronomy with Magnetized Zevatrons

    Armengaud, Eric; Sigl, Guenter; Miniati, Francesco

    2005-01-01

    Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV are produced in magnetized environments such as galaxy clusters, the flux of secondary gamma-rays below ~1 TeV can be enhanced up to several orders of magnitudes compared to unmagnetized sources. A particular source of enhancement are synchrotron and cascade photons from e^+e^- pairs produced by protons from sources...

  16. Very high energy gamma ray astrophysics

    The Whipple Observatory High Resolution Camera will be used in a vigorous program of observations to search for new sources of very-high-energy gamma rays. In addition, a search for antimatter using the moon-earth system as an ion spectrometer will be begun. The first phase of GRANITE, the new 37-element 11-m camera, will be concluded with first light scheduled for September, 1991. The two cameras will operate in support of the Gamma Ray Observatory mission in the winter of 1991/2

  17. Gamma ray spectrometer for Lunar Scout 2

    Moss, C. E.; Burt, W. W.; Edwards, B. C.; Martin, R. A.; Nakano, George H.; Reedy, R. C.

    1993-01-01

    We review the current status of the Los Alamos program to develop a high-resolution gamma-ray spectrometer for the Lunar Scout-II mission, which is the second of two Space Exploration Initiative robotic precursor missions to study the Moon. This instrument will measure gamma rays in the energy range of approximately 0.1 - 10 MeV to determine the composition of the lunar surface. The instrument is a high-purity germanium crystal surrounded by an CsI anticoincidence shield and cooled by a split Stirling cycle cryocooler. It will provide the abundance of many elements over the entire lunar surface.

  18. A Shotgun Model for $\\gamma$ Ray Bursts

    Heinz, S

    1999-01-01

    We propose that gamma ray bursts (GRBs) are produced by a shower of heavy blobs running into circumstellar material at highly relativistic speeds. The gamma ray emission is produced in the shocks these bullets drive into the surrounding medium. The short term variability seen in GRBs is set by the slowing-down time of the bullets while the overall duration of the burst is set by the lifetime of the central engine. A requirement of this model is that the ambient medium be dense, consistent with a strong stellar wind. In contrast to other external shock scenarios, the efficiency of the shock can be close to unity.

  19. Gamma rays induced variation in Plantago ovata

    Plantago ovata Fork., a medicinal herb, requires improvement in seed yield to meet would demand for its seed husk. Mutation breeding has been attempted on account of narrow genetic base of the crop. The mutagen, gamma rays from 60Co sources was tried for its effect on various phenotypic traits, including those related to seed yield. Studies indicate that P. ovata is radio-resistant. Gamma rays also induce alteration in mean and variance of yield related characters which can be exploited to select superior genotypes in this conservative crop

  20. Nuclear forensics using gamma-ray spectroscopy

    Norman, Eric B

    2016-01-01

    Much of George Dracoulis's research career was devoted to utilizing gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the past several years, our research group has made use of both high- and low- resolution gamma ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.