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1

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

Science.gov (United States)

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 material in contrast to the electron beam irradiation process. PMID:23131791

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

2013-01-01

2

Gamma-ray spectroscopy on irradiated fuel rods  

International Nuclear Information System (INIS)

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

3

Gamma ray irradiation for sludge solubilization and biological nitrogen removal  

Energy Technology Data Exchange (ETDEWEB)

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 (BOD{sub 5}) 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.

Kim, Tak-Hyun, E-mail: tkhk@kaeri.re.kr [Radiation Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Lee, Myunjoo [Radiation Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Park, Chulhwan [Department of Chemical Engineering, Kwangwoon University, Seoul 139-701 (Korea, Republic of)

2011-12-15

4

Gamma ray irradiation for sludge solubilization and biological nitrogen removal  

International Nuclear Information System (INIS)

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

Inactivation of citrus tristeza virus by gamma ray irradiation  

International Nuclear Information System (INIS)

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

6

Apoptosis and necrosis in testes irradiated with gamma rays  

International Nuclear Information System (INIS)

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

7

Grafting study of polysulfone polymeric membranes by gamma ray irradiation  

International Nuclear Information System (INIS)

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

8

Gamma-ray tomography of irradiated CANDU reactor fuel  

International Nuclear Information System (INIS)

Gamma ray computerised tomography (CT) methods have been developed to measure the porosity distribution, cracking pattern, and other characteristics of irradiated CANDU power reactor fuel pellets. This paper illustrates the technique and documents a CT study of two 24-mm-long sections of CANDU reactor UO2 fuel elements. Transmission CT was used to map porosity at various longitudinal cross-sections, and to evaluate dish filling, fuel swelling, three-dimensional cracking patterns and crack sizes. Emission CT was used to map approximate distributions of accumulated non-volatile fission products and to extract corrections for transmission scans. This work shows that we currently have a unique quantitative method of non-destructively mapping porosity and cracking in irradiated fuel. The CT techniques are non-destructive and non-invasive. The obtained information is complementary to post-irradiation examination of irradiated fuel by microscopy and ceramography. (author)

9

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

International Nuclear Information System (INIS)

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

10

Photoconductivity of polyethylene pre-irradiated by gamma-ray  

International Nuclear Information System (INIS)

Electronic conduction in various polymeric insulating material was investigated. Specially photocurrent was observed in low density and 30*m thick polyethylene when the sample was exposed by low-intensity white light from a tungsten lamp. A large photo-current was observed for the pre-irradiated sample by high dosage gamma-ray. Photo-current was measured for many factors, wave length, voltage, temperature. Photo-current is fairly sensitive to photons with a certin range of energy (about 0.83eV), which might support that charge carriers are optically released from trap centers, it has approximately the same activation energy as the dark current. A tentative energy diagram for irradiated polyethylene is proposed on the assumption of band model. It includes two kinds of shallow trap and deep trap which are considered to play an important role in electrical conduction of polymeric insulator. (Author)

11

Gamma-ray spectroscopy on irradiated MTR fuel elements  

Science.gov (United States)

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

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

2000-08-01

12

Gamma Rays Irradiation Effects on Polysulfones at Elevated Temperature  

International Nuclear Information System (INIS)

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 temperature

13

Genetic studies on two soybean cultivars irradiated with gamma rays  

International Nuclear Information System (INIS)

In the present study, the effect of gamma irradiation was used in two Egyptian soybean cultivars; Giza-22 and Giza-82, to induce genetic variability with doses of 100, 150 and 200 Gy. Some agronomic characters were tested in M1 and M2 generations single plants. Oil and protein contents were measured from the resulted mutants of the two soybean cultivars at M2 generation. Some genetic parameters were estimated on the mean values of M2 generation. The results showed significant differences induced by gamma ray doses in all studied characters, particularly for 200 Gy in M1 generation. Gamma irradiation increased the genetic variability in M2 generation, which helped in selecting some high yielding mutants and some mutants with high oil and protein contents from the two cultivars. The estimated coefficients of phenotypic variance as well as coefficient of genotypic variance were high for seeds weight/plant, pod weight/plant, number of seeds/plant, number of pods/plant and number of nods/plant which showed better scope in genetic improvement. Heritability in the broad sense was high in most of the studied characters. The expected genetic advance (G.A) from selection was high for number of seeds, for number of pods, for pods weight and for mature plant height

14

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

International Nuclear Information System (INIS)

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

15

Structural analysis of gamma-ray irradiated low-voltage cables  

International Nuclear Information System (INIS)

The low-voltage cable insulators were degraded by four different ageing modes; thermal, low-oxygen thermal, gamma-ray irradiated, and gamma-ray irradiated thermal decomposition methods. Gamma-ray irradiated ones showed deteriorated with different chemical modes shown by Fourier-transform infra-red spectroscopy. Flame-retardant crosslinked polyethylene cable insulators showed degradation of crystal region. In addition, SEM and TEM observation showed the existence of several additives with flame-retardant ethylene-propylene rubber cable insulators. (author)

16

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

International Nuclear Information System (INIS)

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)

17

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

International Nuclear Information System (INIS)

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

18

Degradation of SiGe HBT with reactor pulse neutron and gamma rays irradiation  

Energy Technology Data Exchange (ETDEWEB)

The typical dc electronic parameters degradation of SiGe HBT irradiated by reactor pulse neutron and gamma rays were measured. The mechanisms of transient radiation-induced damage in SiGe HBT were preliminary analyzed.

Liu Shuhuan [Department of Engineering Physics, Tsinghua University, Beijing, 100084 (China) and Northwest Institute of Nuclear Technology, Xi' an 710613 (China)]. E-mail: liupeterson@yahoo.com.cn; Lin Dongsheng [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Guo Xiaoqiang [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Liu Nannan [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Jiang Xinbiao [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Zhu Guangning [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Li, Da [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Wang Zhujun [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Tang Benqi [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Chen Wei [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Zhang Wei [Institute of Microelectronics, Tsinghua University, Beijing, 100084 (China); Zhou Hui [Northwest Institute of Nuclear Technology, Xi' an 710613 (China); Shao Beibei [Department of Engineering Physics, Tsinghua University, Beijing, 100084 (China); Li Junli [Department of Engineering Physics, Tsinghua University, Beijing, 100084 (China)

2006-12-21

19

Degradation of SiGe HBT with reactor pulse neutron and gamma rays irradiation  

International Nuclear Information System (INIS)

The typical dc electronic parameters degradation of SiGe HBT irradiated by reactor pulse neutron and gamma rays were measured. The mechanisms of transient radiation-induced damage in SiGe HBT were preliminary analyzed

20

Induced mutations by gamma ray irradiation to Argomulyo soybean (Glycine max variety  

Directory of Open Access Journals (Sweden)

Full Text Available Hanafiah DS, Trikoesoemaningtyas, Yahya S, Wirnas D. 2010. Induced mutations by gamma ray irradiation to Argomulyo soybean (Glycine max variety. Nusantara Bioscience 2: 121-125. Induced mutation by gamma ray irradiation is one way to increase genetic variability of plants. This research used gamma ray irradiation on low doses (micro mutation. The aim of this research was to know the respons of doses level by micro mutation on gamma ray irridation to the growing and development of Argomulyo variety of soybean [Glycine max (L Merr]. The seeds were irradiated by gamma ray micro mutation doses, namely 0 gray, 50 gray, 100 gray, 150 gray, and 200 gray. Variations that were obtained of each characters at generation M1 and M2 influences plants growth and development either through qualitative and quantitative that finally will influence plants production. The average highest genetic variation at M2 generation of soybean was on 200 Gray doses. Results of the research indicated that gamma ray irradiation on 200 Gray doses effectively caused of plant variation genetic.

DESTA WIRNAS

2010-11-01

 
 
 
 
21

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

International Nuclear Information System (INIS)

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

22

Studies on the nondestructive gamma-ray spectrometry of irradiated nuclear fuels from power reactors  

International Nuclear Information System (INIS)

The gamma-ray intensities of irradiated fuels are nondestructively measured at a reactor site by using a gamma-ray collimator and a Ge detector system. However, there are some difficulties to keep the geometrical arrangement unchanged over a series of the measurement and to calibrate the gamma-ray intensities with absolute values. In order to avoid these disadvantages, an activity ratio measurement has been proposed and continued to be developed. Since 1972, gamma-ray spectrometry of irradiated fuels discharged from power reactors has been carried out in Japan Atomic Energy Research Institute. The purpose of the studies was to examine the applicability of the activity ratio measurement of fission products to evaluate the burnup and related parameters. The present paper summarizes the results of the studies

23

Comparison of electrical properties of ceramic insulators under gamma ray and ion irradiation  

International Nuclear Information System (INIS)

The electrical properties of ceramic insulators of Y2O3, CaZrO3 and Er2O3 were examined under gamma ray and low energy ion beam irradiation. The gamma-ray induced currents increased with the bias voltage. Their radiation induced conductivity (RIC) evaluated from the induced current was almost within one order of magnitude of that predicted from the previous fusion neutron and fission reactor irradiations. Under low energy ion beam irradiation, the induced current from the positive bias voltage was strongly suppressed. From the point of the energy deposition, the magnitude of the ion-induced current was significantly lower than that under gamma-ray and neutron irradiations. A transient change in the induced current at the start of beam irradiation implies that the electric field in the specimen was affected by the unevenness of the distribution of the released electrons and holes. (author)

24

Changes in induced conductivity of heavy irradiated polyethylene with cobalt 60 gamma-rays  

International Nuclear Information System (INIS)

The changes in induced conductivity of pre-irradiated polyethylene samples (low and high density polyethylene) are measured as a function of pre-irradiation doses. Their induced conductivities decrease with pre-irradiation doses. The induced conductivity of high density polyethylene is smaller than of low density polyethylene for pre-irradiated materials. Their causes will be related to the decrease of molecular motion in amorphous region which resulted from heavy cobalt gamma-rays pre-irradiation. (auth.)

25

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

Energy Technology Data Exchange (ETDEWEB)

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

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

26

Characteristics of high energy gamma ray irradiation field  

International Nuclear Information System (INIS)

High energy gamma ray is necessary for energy calibration of neutron detector, and its exposure can be yielded by such fields as while flying high or in space, at particle beam therapy and boron neutron capture therapy. This report describes possible characterization of high energy gamma ray with >2 MeV at fields possibly produced by nuclear reaction with accelerator, and >6 MeV, by activation of cooling water of the accelerator. The first was examined with 10 MeV proton accelerated by National Institute of Radiological Sciences (NIRS) cyclotron AVF930 in C6 course with the targets of graphite, SF6 gas, Al, LiF, Teflon, AlLi, SiN, AlN and Be, for their possible gamma emission by the reactions C12 (p, p' gamma) C12 with 4.439 MeV, F19 (p, alpha gamma) O16 with 2.741-7.116 MeV, Li7 (p, gamma) Be8 with 14.74/17.64 MeV. Gamma ray was measured by simultaneous use of high purity Ge semiconductor detector and BC501A liquid scintillator to discriminate from the effect of neutron flux by photon decay in BC510A. Except escape peaks, gamma ray with 4.4 MeV from C was observed from graphite, and 6.1 MeV from Tefron F, suggesting the possible characterization and examination of response property to the rays. The second was examined with the reaction O16 (n, p) N16 -(beta) + ->O16* emitting 6.165 and 7.153 MeV gamma ray occurring in the cooling water, running the underground room, during generation of high intensity neutron. The ray was found measurable with Ge-detector, of which snd measurable with Ge-detector, of which spectrum gave 6.2 and 7.2 MeV photoelectric peaks, their double escape peaks and annihilation peak of beta+, indicating the possible characterization of detector response to the ray. Characterizations above are under planning in future. (T.T.)

27

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

International Nuclear Information System (INIS)

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)

28

Electron paramagnetic resonance in gamma-ray, electron and neutron flux irradiated sapphire  

Energy Technology Data Exchange (ETDEWEB)

Sapphire is irradiated by gamma-ray, electron and neutron flux, respectively, where defects are identified by means of electron paramagnetic resonance (EPR) spectroscopy. The position and intensity of EPR signal in different sources irradiated sapphire are compared in this paper. The g-factor value are 1.978, 1.982, and 2.010 after gamma-ray, electron and neutron flux irradiation, respectively. They are attributed to F{sup +} color centers induced by irradiation and the difference is due to the lattice distortion induced by irradiation. It is found that EPR signal in irradiated sapphire is dependent on the irradiation source type and dose. Effect of annealing and magnetic field direction on the EPR signal is also discussed. A weak signal varying with the magnetic field direction is found in neutron irradiated sample.

Zhang, H.L., E-mail: zhanghl818@gmail.com [Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, M.F. [Center for Composite Materials, Harbin Institute of Technology, Harbin 150080 (China); Hu, Z.G. [Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Han, J.C.; Guo, H.X.; Xu, C.H. [Center for Composite Materials, Harbin Institute of Technology, Harbin 150080 (China)

2012-11-15

29

Gamma-ray spectrometric analysis of nuclides formed in thorium by neutron irradiation  

International Nuclear Information System (INIS)

Gamma-ray spectrometric analysis was employed to determine the nuclides formed in thorium by neutron irradiation. Thorium sample was irradiated by neutron from a pure thermal neutron field, neutron field of Cd ratio of about 4, and epithermal neutron field, respectively. The former irradiation was carried out in a thermal neutron column provided for medical uses of neutrons, and the latters were done in the F-ring position of TRIGA II research reactor of Musashi Institute of Technology. The gamma-ray spectra were obtained and analyzed by employing a fully automatic gamma-ray analysis system named ''GAMA: giant frog:-SYSTEM'' developped by Musashi Institute of Technology. The formation of Pa-233 (U-233) was discussed quantitatively with respect to the difference of the neutron field. (author)

30

Tetraploid induction by gamma-ray irradiation in mulberry  

International Nuclear Information System (INIS)

Vigorously growing mulberry trees were exposed to 5 kR of gamma rays at the rate of 0.2 kR/h and 5 kR/h and successively pruned three times in two growing seasons. The frequency of tetraploids induced was much higher than that of mutations, though almost all of them were cytochimeras. By tracing a process of the formation of cytochimeras it is inferred that a mutation is a unicellular event, with radiation treatment on materials in a multicellular constitution such as shoot apices resulting in the formation of chimeras, periclinal and mericlinal chimeras. (author)

31

Silver nanoparticles dispersing in chitosan solution: Preparation by {gamma}-ray irradiation and their antimicrobial activities  

Energy Technology Data Exchange (ETDEWEB)

Silver nanoparticles were prepared by {gamma}-ray irradiation-reduction under simple conditions, i.e., air atmosphere, using chitosan as a stabilizer. The nanoparticles were spherical with an average size of 7-30 nm as observed from TEM. The size decreased when chitosan concentration increased, while it increased with increasing {gamma}-ray dose and initial silver nitrate content. The obtained silver nanoparticles dispersed in a 0.5% (w/v) {gamma}-ray irradiated chitosan-aqueous acetic acid solution were stable for more than 3 months without tendency to precipitate. The silver nanoparticles exhibited antimicrobial activities against Escherichia coli and Staphylococcus aureus. The results suggest that silver nanoparticles dispersed in chitosan solution can be directly applied in antimicrobial fields, including antimicrobial food packaging and biomedical applications.

Yoksan, Rangrong [Department of Packaging Technology and Materials, Faculty of Agro-Industry, Kasesart University, 50 Paholyothin Road, Ladyao, Jatujak, Bangkok 10900 (Thailand); Division of Physico-Chemical Processing Technology, Faculty of Agro-Industry, Kasesart University, Bangkok 10900 (Thailand)], E-mail: rangrong.y@ku.ac.th; Chirachanchai, Suwabun [The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok 10330 (Thailand)

2009-05-15

32

Radiation-sensitive field effect transistor response to gamma-ray irradiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of gate bias during gamma-ray irradiation on the threshold voltage shift of radiation sensitive p-channel MOSFETs determined on the basis of transfer characteristics in saturation has been investigated. It has been shown that for the gate bias during the irradiation of 5 V and 10 V the sensitivity of these transistors can be presented as the threshold voltage shift and the absorbed irradiation dose ratio. On the bases of the subthreshold characteristics and transfer charac...

Pejovi? Mili? M.; Pejovi? Mom?ilo M.; Jaki? Aleksandar B.

2011-01-01

33

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

International Nuclear Information System (INIS)

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

34

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

CERN Document Server

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)

Kang, A G; Liu, J Q; You, Z

2003-01-01

35

EPR investigations in NaNO2 monocrystals irradiated with gamma rays  

International Nuclear Information System (INIS)

NaNO2 monocrystals were investigated by EPR method. They were irradiated with gamma rays in room temperature. Radiation doses of 105-109R were applied. EPR spectrum with three lines considerable distant from each other and five lines not so distant from each other, was observed. (Z.M.)

36

Investigations of chromium-doped CaF2 monocrystals irradiated with gamma rays  

International Nuclear Information System (INIS)

Paramagnetic Cr3+ and Cr4+ centres were formed in chromium-doped CaF2 single crystals irradiated with gamma rays; at the same time, there was drop in the number of Cr+ and Cr2+ centres. The applied radiation dose ranged from 105R to 107R (1,2 MeV). (author)

37

Comparison of some oxidation effects in polyethylene film irradiated with electron beam or gamma rays  

International Nuclear Information System (INIS)

Oxidation of a low-density polyethylene film, occurring upon modification with both high-energy electron beam and gamma rays, was studied. The oxidation effects were followed with the techniques of FTIR and XPS. It was found that the oxidation level grew with the irradiation dose much faster when the gamma rays were used than with the electron beam. The trans-vinylene, hydroxyl, and ketone groups were major oxidation products formed in the bulk of the film while the hydroxyl and ester groups formed in the film surface layer. The oxidation level of the latter reached ca. 14% upon the dose of 150 kGy in the case of the gamma rays, i.e., it was approximately three times as much as when the high-energy electron beam was applied

38

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

International Nuclear Information System (INIS)

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

39

A 60Co gamma-ray underwater irradiation test facility  

International Nuclear Information System (INIS)

An irradiation facility with 3.7 x 1014 Bq of 60Co for textile research was constructed adopting the form of underwater irradiation and making use of used radiation sources. The facility is simple in structure, and easy to operate with low building costs. The effective irradiation space is a cylinder of ?225 x 250 mm, in which irradiation uniformities (Dmax/Dmin) range in 1.28-1.40, 1.17-1.30 and 1 respectively. It is suitable for irradiation of samples of various materials and for scientific experiments

40

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

 
 
 
 
41

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

International Nuclear Information System (INIS)

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

42

Deep level defects in gamma-ray irradiated Ge doped with Pb or Sn  

Energy Technology Data Exchange (ETDEWEB)

Deep level transient spectroscopy has been used to investigate the electrical properties of deep defect states in ..gamma..-ray irradiated Ge doped with the isoelectronic elements Pb or Sn. Three deep levels are observed in the irradiated Pb-doped Ge and two deep levels observed in the Sn-doped Ge. For the same ..gamma..ray irradiation doses, Ge crystals grown from graphite crucibles and doped with Pb or Sn show about two-thirds the total density of deep level defects observed in undoped Ge grown from synthetic quartz crucibles. All of the defect states observed were removed by a 1 hour, 250/sup 0/C thermal anneal, and all but the Esub(c) - 0.39 eV state in the Pb-doped material were neutralized by exposure to a low pressure atomic hydrogen plasma.

Tavendale, A.J.; Pearton, S.J. (Australian Atomic Energy Commission Research Establishment, Lucas Heights. Physics Div.)

1982-09-01

43

Physico-chemical characterization of gamma rays irradiated crotamine  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

44

Physico-chemical characterization of gamma rays irradiated crotamine  

International Nuclear Information System (INIS)

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)

45

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

International Nuclear Information System (INIS)

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

46

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

International Nuclear Information System (INIS)

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

47

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

Directory of Open Access Journals (Sweden)

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.

Cappello Salvatore G.

2014-01-01

48

Stimulation of plant growth by low-dose irradiation of gamma ray on leaf vegetable seeds  

International Nuclear Information System (INIS)

Air-dried seeds of Komatsuna greens were irradiated with 1 or 2 kR of 60Co gamma rays at the dose rate of 5 kR/h. Plant growth was promoted by irradiation, particularly under the following conditions: Cultivation in hot and dry summers with abundant sunshine, and in cold winters with insufficient sunshine and large daily temperature fluctuation. Height of the irradiated plants was taller than that of non-irradiated ones, paticularly in an early period of growth. By irradiation, The increase in fresh weight at the time of harvest was 10 - 80%. Seed irradiation did not increase the number of leaves, but it increased leaf area. This growth-promoting effect of seed irradiation was reserved in the seed for about 3 years. The nutrient composition of the irradiated plants was the same as that of the non-irradiated ones. (Kaihara, S.)

49

Flowcytometry of {gamma}-ray irradiated mouse ovary  

Energy Technology Data Exchange (ETDEWEB)

This study was carried out to evaluate the biochemical and morphological effects of ionizing radiation on ovary. Immature mice (ICR, 3 week-old) were irradiated at a dose of LD{sub 80(30)} at KAERI. The ovaries were collected after 6 hours, 12 hours, 1 day, and 2 days post irradiation. To analyze the morphological changes, histological staining with hematoxylin-eosin, immuno- histochemical preparation using in situ 3'-end labeling was performed. DNA fragmentation analysis and flowcytometric evaluation of DNA extracted from whole ovary were performed. As a result of DNA fragmentation analysis, DNA fragments with 185, 370, and 555 base pairs were clearly shown at 6 hours post irradiation. The percentage of A{sub 0} cell cycle was significantly increased in the irradiated group than control. In situ 3'-end labeled follicles were increased at 6 hours post irradiation. The radiation-induced follicular atresia was taken place via an apoptotic degeneration. And this degeneration broke out very fast and acutely. Therefore, it was concluded that radiation-induced follicular degeneration was mediated by apoptosis as the spontaneous atresia. The present results can provide the experimentral basis for studying the radiation-induced cell death.

Kim, J. K.; Lee, C. J. [KAERI, Taejon (Korea, Republic of); Song, K. W.; Kim, S. S.; Yoon, Y. D. [Hanyang Univ., Seoul (Korea, Republic of)

1998-10-01

50

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

International Nuclear Information System (INIS)

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)

51

Radiation resistance of elastomers  

International Nuclear Information System (INIS)

Various data has indicated that some elastomers have much higher radiation resistance than Viton. Nine samples of elastomers were irradiated with gamma rays. Two Ethylene Propylene Diene compounds, EPDM's, were found to exhibit acceptable properties for o-rings after radiation levels of 5x108 rads, while Viton failed at 1x107 rads. Vacuum tests also were favorable so EPDM o-rings were chosen as seals in the Energy Saver cryostat vacuum system

52

ESR study of gamma-ray irradiated synthetic calcium carbonates  

International Nuclear Information System (INIS)

Nine commercial calcium carbonates, plus 3 calcium carbonates which have been synthesized in the laboratory and 2 natural ones, have been ?-ray irradiated at room temperature. From these 14 samples, 11 are pure calcite, 2 are pure aragonite and 1 is a mixture of calcite and aragonite. Important differences in their ESR spectra are observed. A preheating treatment (up to 6000C) was performed in order to standardize the ESR spectra. After a heating treatment at 6000C for 2 h, all the samples are in the calcite phase; 6 of them mainly exhibit, after ?-ray irradiation, a paramagnetic species with gparallel=2.0024 and gperpendicular =2.0037 (CO33-?). A k-value of ?0.1 for two radiolytic species (one at 2.0052 and the other, anisotropic, at 2.0037 and 2.0024) of three commercial samples of calcite is obtained by means of ?-particle irradiation with a 241Am source. (author)

53

Priming effect on a polycrystalline CVD diamond detector under {sup 60}Co {gamma}-rays irradiation  

Energy Technology Data Exchange (ETDEWEB)

The priming effect on a polycrystalline chemical vapor deposition (CVD) diamond film detector caused by irradiation with {sup 60}Co {gamma}-rays has been investigated. Charge collection efficiencies of the detector for {alpha}-particles and {gamma}-rays detection were determined in both the normal state and the pumped state. The duration of the priming effect and its relationship with bias voltage were also studied. The results show that the priming effect may clearly improve charge collection efficiency, with an increase of 6% for {alpha}-particles and 13% for {gamma}-rays at 600 V saturation bias voltage. The priming effect can be completely retained for 40 min after irradiation, and it begins to gradually disappear within 12 h. In addition, the effect is more easily induced when bias voltage is applied than in the absence of any bias voltage. The experiments also demonstrated that irradiation incident on the growth surface may induce higher charge collection efficiency than irradiation incident on the substrate surface.

Lan, Lei, E-mail: leilan1029@163.com [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China); Xiaoping, Ouyang [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China); Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Xinjian, Tan; Liangbin, Xia; Na, Cao [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China); Bing, Liu [School of Nuclear Science and Engineering, North China Electric Power University, Beijing 102206 (China); Xiaodong, Zhang [Northwest Institute of Nuclear Technology, P.O. Box 69-9, Xi' an 710024 (China)

2012-04-21

54

Accumulation efficiency of cancer stem-like cells post {gamma}-ray and proton irradiation  

Energy Technology Data Exchange (ETDEWEB)

Ionizing radiation (IR) has been proven to be a powerful medical treatment in cancer therapy. Rational and effective use of its killing power depends on understanding IR-mediated responses at the molecular, cellular and tissue levels. Increasing evidence supports that cancer stem-like cells (CSCs) play an important role in tumor regrowth and spread post radiotherapy, for they are resistant to various therapy methods including radiation. Presently, SW620 colon carcinoma monolayer culture cells were irradiated with {gamma}-rays and protons of 2 Gy. Then apoptosis, clonogenic survival and the expression of CD133{sup +} protein were examined. The results showed that there was no significantly difference either on long-term clonogenic survival or on short-term apoptosis ratio. However, compared with {gamma}-rays, irradiation with protons was less efficient to accumulate CSCs at the same dose, although both protons and {gamma}-rays can significantly accumulate the CD133{sup +} CSCs subpopulation. In addition, the results of sphere formation assay also confirmed that proton irradiation is less efficient in CSCs accumulation, suggesting proton irradiation might have higher efficiency in CSCs elimination for cancer radiotherapy.

Quan Yi; WangWeikang; Fu Qibin; Mei Tao; Wu Jingwen; Li Jia [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Yang, Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wang Yugang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

2012-09-01

55

Radiation Damage of BGO Scintillator Irradiated by 60Co Gamma-ray  

International Nuclear Information System (INIS)

The major advantages of Bi4Ge3O12(BGO) are its high density(7.13 g/cm3) and the large atomic number(83) of the bismuth component. Because of easiness to handle and use, BGO is commonly available as crystals of reasonable size. When exposed to radiation of high energy particles or other sources such as gamma-rays and X-rays, BGO crystal will emit a green fluorescent light with a peak wavelength of 480 nm. Also BGO crystal has high stopping power, high scintillation efficiency and non-hygroscopicity. Small volume BGO crystals are widely used in nuclear medicine diagnostic systems, particularly Positron Emission tomographs(PET) and Computed Tomography Scanners (CTS). In gamma-ray spectroscopy, NaI(Tl) crystals was used as the most suitable scintillation detectors of gamma-rays. After BGO was invented in the late 1970s, it gradually took the place of NaI(Tl) as the scintillation detector in most PET and CTS systems because of its high stopping power, light yield and decay time, as well. Light yield dependence on irradiation dose seems to be one of the most decisive parameter for practical using of these scintillators in various applications. The main goal of our investigation is to compare the scintillation properties of BGO before and after gamma ray irradiation with a crystal of 10x10x10 mm3 size. In this work, we measured and compared the radiation damage of BGO crystal at accumulated doses of 1 kGy and 10 kGy usinaccumulated doses of 1 kGy and 10 kGy using 60Co gamma-rays

56

Gamma-ray irradiation of a boreal forest ecosystem  

International Nuclear Information System (INIS)

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

57

Effect of gamma-ray irradiation on corrosion of austenitic stainless steel in boiling pure nitric aced solution  

International Nuclear Information System (INIS)

The corrosion behavior of austenitic stainless steel (R-SUS304ULC) was studied in boiling pure nitric acid solution under gamma-ray irradiation. Corrosion experiments, immersion and electrochemical tests including the measurement of potential, polarization curve and AC impedance. were carried out by making use of a 60Co gamma-ray source in order to evaluate the gamma-ray effect on corrosion of 304ULC. The radiolysis products of nitric acid, furthermore, were analyzed to discuss the electrochemical effect of the gamma-ray irradiation on the pure nitric acid solution. Consequently, it was recognized that the corrosion of 304ULC in boiling pure nitric acid solution was slightly accelerated by gamma-ray irradiation, though it is insignificant from an engineering viewpoint. In contrast with this trend, the corrosion potential of 304ULC(Ecorr) and the redox potential of pure nitric acid solution were induced to shift towards the less noble ride by gamma-ray irradiation. This shift of potential is concerned with the radiolysis products of nitric acid such as NOx and HNO2 formed in dependence on exposure dose rate. The acceleration of corrosion is considered as caused by an enhancement in the current across the passive film by the gamma-ray irradiation on the stainless steel surface. (author)

58

Control of drug release from biodegradable polymer drug delivery system by {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

This study aimed to develop a drug delivery system of superior drug releasing properties and to find factors to control the properties of microspheric and hydrogel polymers. Further, techniques to control the drug release properties by {gamma}-ray exposure were investigated. The effects of gelatin concentration and the degree of cross linkage on the release rate of temperature-responding hydrogel were investigated in the previous year. In this year, the mobility of a hydrogel polymer was investigated using dynamic light scattering photometry. Biodegradable polymer such as dextran, gelatin, polyhydroxyethylaspartamide was dissolved in dimethylaminopyridine and incubated with glycidylymethacrylamide to produce its methacryl derivatives and the polymer solution was exposed to {gamma}-ray in the presence of a drug. Then, {sup 1}H-NMR spin-spin relaxation time was determined for estimation of mobility and mesh size of the polymer. In addition, the drug release rate for the hydrogel polymer after {gamma}-ray exposure was estimated. The drug release rate of hydrogel was demonstrated to be dependent on its mesh size and the mobility of the polymer was closely correlated to the mesh size. Thus it was demonstrated that spin-spin relaxation time (T{sub 2}) was available as an indicator for mobility of gel-like polymers. Up to now, synthetic polymers that were not biodegradable have been used as stimuli-responding gel. However, it became possible to produce a stimuli-responding gel by the hydrogel preparation method using {gamma}-ray irradiation. (M.N.)

Yoshioka, Sumie; Aso, Yukio; Kojima, Shigeo [National Inst. of Health Sciences, Tokyo (Japan)

2000-02-01

59

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

International Nuclear Information System (INIS)

Livestock wastewater generally contains high strength of organics (COD), ammonia nitrogen (NH4+ -N), phosphate phosphorus (PO43- -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 NH4+ :Mg2+ : PO43- mol ratio of struvite crystallization. For the digested livestock wastewater, COD, NH4+ -N and PO43- -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, NH4+ -N and PO43- -P concentration

60

Comparison of irradiation effects of electrons and gamma rays on PVC samples  

International Nuclear Information System (INIS)

Samples of polyvinyl chloride (PVC) were irradiated at a dose of 15 MGy using both electrons and gamma rays. The resultant material shows differences attributed to the very different dose rates in each type of radiation. In addition, a method useful in separating the highly cross-linked portion of the sample has been tested. Transmission electron microscopy, electron stimulated desorption and energy dispersive spectroscopy have been applied in the characterization of the irradiated material. We show that this resultant material, after irradiation, consists mainly of carbon-like material with distinct crystallographic phases which, in some cases, resemble graphitic structures. (author)

 
 
 
 
61

Comparison of irradiation effects of electrons and gamma rays on PVC samples  

Science.gov (United States)

Samples of polyvinyl chloride (PVC) were irradiated at a dose of 15 MGy using both electrons and gamma rays. The resultant material shows differences attributed to the very different dose rates in each type of radiation. In addition, a method useful in separating the highly cross-linked portion of the sample has been tested. Transmission electron microscopy, electron stimulated desorption and energy dispersive spectroscopy have been applied in the characterization of the irradiated material. We show that this resultant material, after irradiation, consists mainly of carbon-like material with distinct crystallographic phases which, in some cases, resemble graphitic structures.

Cota, L.; Avalos-Borja, M.; Adem, E.; Burillo, G.

1994-12-01

62

The gamma-ray irradiation sensitivity and dosimetric information instability of RADFET dosimeter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The gamma-ray irradiation sensitivity to radiation dose range from 0.5 Gy to 5 Gy and post-irradiation annealing at room and elevated temperatures have been studied for p-channel metal-oxide-semiconductor field effect transistors (also known as radiation sensitive field effect transistors or pMOS dosimeters) with gate oxide thicknesses of 400 nm and 1 mm. The gate biases during the irradiation were 0 and 5 V and 5 V during the annealing. The radiation and t...

Pejovi? Mili? M.

2013-01-01

63

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

International Nuclear Information System (INIS)

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

64

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

International Nuclear Information System (INIS)

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

65

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

International Nuclear Information System (INIS)

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

66

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Human, S.; Andreani, S.; Sihono; Indriatama, W. M.

2011-01-01

67

Glasses, Coatings, Glues and Gamma-ray Irradiation  

Energy Technology Data Exchange (ETDEWEB)

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.

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

68

Glasses, Coatings, Glues and Gamma-ray Irradiation  

International Nuclear Information System (INIS)

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

69

Thermally stimulated current of gamma-ray irradiated polyethylene  

International Nuclear Information System (INIS)

Measurement was made on the thermally stimulated current (TSC) of high density polyethylene irradiated with ?-ray at room temperature in air. The results were examined on the basis of the traps that capture the dipoles and carriers formed by the irradiation. The temperature of the samples was raised from -2000C up to 1500C at a definite rate between 0.750C/min and 6.60C/min. A typical result showed that four peaks of the TSC were present at -1600, -1200, -200, and 1200C. These are named ?', ?, ?, and ?, respectively. The results of analysis on these peaks showed that the peak ? was attributable to the liberation of frozen polarization, which had been formed by the thermal activation of carriers. The ? peak was attributable to the dipole of carbonyl group formed by the ?-ray irradiation. This peak well agreed with the main dispersion. The temperature Tm, at which the ? peak was the highest was about -1200C. The nature of this peak was not confirmed. The activation energy of ?, ?, and ? peaks, determined by partial heating method was 1.43, 0.5, and 0.19 eV, respectively. Discussion is made on the discrepancies among the data in existing literatures. (Fukutomi, T.)

70

Radiation resistance of a gamma-ray irradiated nonlinear optic chromophore  

Science.gov (United States)

The radiation resistance of organic electro-optic and optoelectronic materials for space applications is receiving increased attention. An earlier investigation reported that guest-host poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- V?) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. To provide further evidences to the observed radiation stability, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data.

Zhang, Cheng; Taylor, Edward W.

2009-11-01

71

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-12-01

72

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

International Nuclear Information System (INIS)

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

73

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

International Nuclear Information System (INIS)

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 + 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)

74

Economic effectiveness of irradiation with gamma rays on maize grains  

International Nuclear Information System (INIS)

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

75

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

International Nuclear Information System (INIS)

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. (note)

76

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

Science.gov (United States)

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

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

2009-11-21

77

Effect of irradiation (gamma rays) on the biology of Eimeria tenella oocysts  

Energy Technology Data Exchange (ETDEWEB)

Effect of gamma rays on the biology of the progeny of the irradiated Eimeria tenella oocysts was investigated. The parent inoculum of sporulated oocysts was exposed to 5 to 60 kR (gamma rays). These oocysts were fed to chicks. The oocysts voided by the chicks were collected and sporulated. The sporulation rate, pathogenicity, immunogenicity and reproduction potential of these oocysts--the progeny of the irradiated oocysts--were compared with those of the unirradiated oocysts. It was observed that increase of irradiation dose caused progressive decrease in the pathogenicity of the oocyst suspension. The oocysts exposed to 30 and 40 kR produced only mild infections whereas those exposed to 50 kR and above were noninfective. No difference in pathogenicity, immunogenicity and reproduction potential of unirradiated oocysts and the oocysts progeny of the irradiated oocysts was seen. It was concluded, therefore, that the effect of irradiation was limited to the inoculum exposed to it, and was not transmissible to the progeny of the irradiated oocysts.

Bajwa, R.S.; Gill, B.S.

1977-01-01

78

Physical properties of polyethylene irradiated with 60Co gamma-rays  

International Nuclear Information System (INIS)

The Krigbaum's theoretical equation was studied, and its application to polyethylene which was irradiated with gamma-ray was examined. The relation between the variation of the modulus of bulk crystalline polymer with degradation and the Krigbaum's equation was investigated. The method of estimating the variation of molecular chain forms with degradation according to the theoretical equation was studied. The material investigated was medium density polyethylene. The modulus of the sample was measured at different temperature. The initial Young's modulus Eo was obtained. The sample was exposed to the gamma-ray from Co-60. The results indicated that the amorphous chains in crystalline polymer varied from inverse Langevin chains to Gaussian chains with rising temperature, and the Krigbaum's parameter N(t) does not depend on the degree of degradation of the sample. (Kato, T.)

79

DNA fragmentation in AG1522 human fibroblasts irradiated with gamma-rays and charged particles: experimental  

International Nuclear Information System (INIS)

The specific pattern of energy deposition at cellular level by protons and HZE particles (the components of space radiation of major concern) is believed to produce spatially correlated damage in the DNA which is critical for radiobiological effects. AG1522 human fibroblasts were irradiated with low-energy protons (0.88 MeV) at the Laboratori Nazionali di Legnaro (Padova, Italy), with 1 and 5 GeV/u Fe ions at the Brookhaven National Laboratory (USA) and with 414 and 115 MeV/u Fe ions at the National Institute for Radiological Sciences (Chiba, Japan). Gamma-rays were used as reference radiation. The DNA fragmentation patterns have been investigated using calibrated Pulsed Field Gel Electrophoresis (PFGE) in the size range 23 kbp - 5.7 Mbp. The results until now obtained show linear, or almost linear, increases of DSB with the dose. DSB yields are in the following increasing order: gamma-rays, 115 MeV/u Fe ions, then protons and 414 MeV/u Fe ions very close each other, and then 1 and 5 GeV/u Fe ions, also very close each other. When the same data were considered as a function of particle fluence, the order is different with 115 MeV/u Fe ions being the most effective particles per unit fluence. The total number of fragments per particle, in the size range considered, increases with LET. Fragmentation spectra shows that the frequency distributions of fragments induced by charged particles are shifted towards smaller sizes with respect to that induced by comparable doses opect to that induced by comparable doses of gamma-rays. A more detailed analysis is given in 'DNA fragmentation in AG1522 human cells irradiated with gamma-rays and charged particles: theoretical analysis' by Belli et al (presentation at this meeting)

80

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

International Nuclear Information System (INIS)

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

 
 
 
 
81

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

International Nuclear Information System (INIS)

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

82

Monitoring index of the cameras during the high dose rate gamma ray irradiation  

International Nuclear Information System (INIS)

When we examined TEPCO's Fukushima Daiichi nuclear power station unit 3 reactor building basement torus room investigation video, we found dozens of speckles in the entire image frame. Generally, speckles occur in a CCD/CMOS image when the CCD/CMOS camera is exposed to high dose gamma ray source. In the above torus room investigation image by the Survey Runner robot system, the gamma ray dose rate was about 100mSv/h. The dozens of speckles in the entire image (640x480) are not obstacles to examine the unit 3 reactor building basement torus room situation closely. Analyzing other videos, as a second investigation inside the primary containment vessels (approx. 500?1000mm inside of the internal wall) in the unit 2 reactor of the Fukushima Daiichi nuclear power station using an industrial endoscope, dense speckles were observed in the investigation image. The gamma ray dose rate was 30?70 Sv/h at the measurement location. The overwhelming number of speckles in the investigation image are a hindrance to scrutinize the inside situation of the primary containment vessels of the unit 2 reactor. The CCD/CMOS cameras, which are loaded on the robot system, are generally used as the eye of the robot and monitoring unit. A major problem that arises when dealing with images provided by CCD/CMOS cameras under severe accident situations of a nuclear power plant is the presence of speckles owing to the high dose rate gamma irradiation fields. To use a CCD/CMOS camera as a monitor To use a CCD/CMOS camera as a monitoring unit in the high radiation area, the legibility of the camera image in such intense gamma radiation fields should therefore be defined. In this paper, we describe the monitoring index as a figure of merit of the camera's legibleness under a high dose rate gamma ray irradiation environment. From the low dose rate (2.11 Gy/h) to the high dose rate (200 Gy/h) level, the legible performances of the cameras owing to the speckles are evaluated. The numbers of speckles, generated by the gamma ray irradiation, in the camera image are calculated by an image processing technique. The relation between the legibility of the camera image and the numbers of speckles is also presented

83

Monitoring index of the cameras during the high dose rate gamma ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

When we examined TEPCO's Fukushima Daiichi nuclear power station unit 3 reactor building basement torus room investigation video, we found dozens of speckles in the entire image frame. Generally, speckles occur in a CCD/CMOS image when the CCD/CMOS camera is exposed to high dose gamma ray source. In the above torus room investigation image by the Survey Runner robot system, the gamma ray dose rate was about 100mSv/h. The dozens of speckles in the entire image (640x480) are not obstacles to examine the unit 3 reactor building basement torus room situation closely. Analyzing other videos, as a second investigation inside the primary containment vessels (approx. 500{approx}1000mm inside of the internal wall) in the unit 2 reactor of the Fukushima Daiichi nuclear power station using an industrial endoscope, dense speckles were observed in the investigation image. The gamma ray dose rate was 30{approx}70 Sv/h at the measurement location. The overwhelming number of speckles in the investigation image are a hindrance to scrutinize the inside situation of the primary containment vessels of the unit 2 reactor. The CCD/CMOS cameras, which are loaded on the robot system, are generally used as the eye of the robot and monitoring unit. A major problem that arises when dealing with images provided by CCD/CMOS cameras under severe accident situations of a nuclear power plant is the presence of speckles owing to the high dose rate gamma irradiation fields. To use a CCD/CMOS camera as a monitoring unit in the high radiation area, the legibility of the camera image in such intense gamma radiation fields should therefore be defined. In this paper, we describe the monitoring index as a figure of merit of the camera's legibleness under a high dose rate gamma ray irradiation environment. From the low dose rate (2.11 Gy/h) to the high dose rate (200 Gy/h) level, the legible performances of the cameras owing to the speckles are evaluated. The numbers of speckles, generated by the gamma ray irradiation, in the camera image are calculated by an image processing technique. The relation between the legibility of the camera image and the numbers of speckles is also presented.

Cho, Jai Wan; Jeong, Kyung Min [KAERI, Daejeon (Korea, Republic of)

2012-10-15

84

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

International Nuclear Information System (INIS)

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

85

Studies on the effect of gamma-rays irradiation on the virulence and immunogenicity of Eimeria tenella oocysts  

International Nuclear Information System (INIS)

Complete attenuation of the infective oocysts of Eimeria tanella was obtained with a gamma ray dose of 15000r. Above this dose, pathogenicity and the sensitivity of the disease decreased. There was no difference in the level of immunity induced with irradiated and non-irradiated oocysts, but the mortality with the irradiated oocysts was much lower. (ARA)

86

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS  

Energy Technology Data Exchange (ETDEWEB)

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

Clark, E.

2011-09-22

87

Radiation-resistant characteristics of optical fiber irradiated with gamma rays at low dose rates  

International Nuclear Information System (INIS)

Production of GI type fibers, which are now widely used, becomes easy if P is added to them. It is known, however, that P-added fibers suffer a loss in proportion to time when irradiated with gamma rays. This study is aimed at investigating the increase in loss in fibers which is expected to take place under the actual service conditions, where they tend to be exposed to gamma rays at a low dose rate. The sample used is SiO2-GeO2-P2O5 fiber of GI type. Effects of dose rate and irradiation time on induced loss are observed and results obtained are discussed. It is shown that induced loss does not depend on dose rate and that it increases with increasing irradiation time. Accordingly, the maximum permissible total dose would be about 40R and 20R for light of 1.3 ?m and 0.85 ?m wavelength, respectively, irrespective of the dose rate, if a margine of 0.1 dB/km is taken in the design for the system. It is also observed that the increase in loss is depressed when light of 1.3 ?m is used, though the depressed loss is regained when the fiber is left to stand after the irradiation. A model is proposed to explain this phenomenon. (Nogami, K.)

88

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

International Nuclear Information System (INIS)

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

89

Radiation-sensitive field effect transistor response to gamma-ray irradiation  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of gate bias during gamma-ray irradiation on the threshold voltage shift of radiation sensitive p-channel MOSFETs determined on the basis of transfer characteristics in saturation has been investigated. It has been shown that for the gate bias during the irradiation of 5 V and 10 V the sensitivity of these transistors can be presented as the threshold voltage shift and the absorbed irradiation dose ratio. On the bases of the subthreshold characteristics and transfer characteristics in saturation using the midgap technique we have determined the densities of radiation induced oxide traps and interface traps responsible for the threshold voltage shift. In addition, the charge pumping technique was used to determine the energy density of true interface traps. It has been shown that radiation-induced oxide traps have dominant role on threshold voltage shift, especially for gate biases during the irradiation of 5 V and 10 V.

Pejovi? Mili? M.

2011-01-01

90

Radiological and genetic effect of gamma-rays in irradiation wetted cotton seeds  

International Nuclear Information System (INIS)

Two cotton cvs (Chirpan 433 and Pavlikeni 73), three periods of seed wetting (24 and 48h) and three irradiation rates (1000 and 2000 rad) were investigated. Gamma-rays were found to inhibit the growth in the first phases of development along with pod weight, yield per plant and survival reduction. Fiber lenght and output were not influenced by the radioactive factor. Chirpan-433 proved more radio-resistant than Pavlikeni-73. The most effective dose for inducing mutation changes in both cvs studied, which did not differ considerably in their mutability, was 2000 rad combined with the 24h period of seed wetting

91

Effect of gamma-ray irradiation on the surface states of MOS tunnel junctions  

Science.gov (United States)

Gamma-ray irradiation with doses up to 8 megarad produces no significant change on either the C(V) or the G(V) characteristics of MOS tunnel junctions with intermediate oxide thicknesses (40-60 A), whereas the expected flat-band shift toward negative electrode voltages occurs in control thick oxide capacitors. A simple tunneling model would explain the results if the radiation-generated hole traps are assumed to lie below the valence band of the silicon. The experiments also suggest that the observed radiation-generated interface states in conventional MOS devices are not due to the radiation damage of the silicon surface.

Ma, T. P.; Barker, R. C.

1974-01-01

92

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

International Nuclear Information System (INIS)

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.

93

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

International Nuclear Information System (INIS)

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

94

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

International Nuclear Information System (INIS)

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.

95

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-07-01

96

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

International Nuclear Information System (INIS)

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

97

Effects of gamma-rays irradiation on tracking resistance of organic insulating materials  

International Nuclear Information System (INIS)

This paper describes the influence of gamma-rays irradiation on tracking failure of organic insulating materials by use of the IEC Publ.112 method. Tracking resistance of organic insulating materials under wet polluted condition has been studied by many investigators with a test method of the IEC Publ.112. The investigations on irradiation effects on tracking resistance should be enhanced due to the increasing usage of organic insulating materials in the radiation environments. The tracking resistance seems to be affected by gamma-irradiation, but the knowledge on the influence of gamma-irradiation is quite a few and systematic studies are needed. In this paper, modified polyphenylene oxide, polybutylene naphthalate, modified polycarbonate and polybutylene terephthalate which were irradiated in air until 1x107R and 1x108R with dose rate of 106R/hr using 60Co gamma-source have been employed. The total dose effects on the number of drops to tracking failure, contact angle and charges of scintillation have been studied. As the total doses are increased, the number of drops to tracking failure decreases with polybutylene terephthalate. On the other hand, the number of drops to tracking failure increases with polybutylene naphthalate and modified polycarbonate when the total doses are increased. The effects of gamma-rays irradiation on tracking failure are due to radiation-induced degradation or cross-linking of organic insulatintion or cross-linking of organic insulating materials. When the organic insulating materials are degraded by gamma-irradiation, the tracking resistance decreases, but for cross-linking type materials, the tracking resistance increases. (author)

98

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

Science.gov (United States)

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

Nath, A. K.; Medhi, Nirmali

2013-10-01

99

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

International Nuclear Information System (INIS)

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

100

Effects of growth substances on rice seedlings grown from seeds irradiated with gamma rays  

International Nuclear Information System (INIS)

Studies were made on the modifications of biological effects caused by ionizing radiations by post-treatment with growth substances, i.e., gibberellic acid (GA3), indole acetic acid (IAA) and indole butyric acid (IBA). Dormant rice seeds (moisture content 13%) variety IR8 were exposed to gamma ray doses of 10, 20, 30, and 40 kR. The irradiated and non-irradiated seeds were soaked for 24 hr in 10 ppm of either GA3, IAA, IBA or distilled water at 290C. Gamma rays induced a remarkable decrease in plant height. However, reversal of the radiation effect was obtained by applying GA3, IAA or IBA. The magnitude of the reversal effect decreased with increasing doses of gamma rays. The lengths of the coleoptile and the first leaf were markedly decreased by the radiation treatment. The application of IAA and IBA produced no significant reversal effect in either case but GA3 showed a slight reversal for both parameters. Seminal root length was inhibited by radiation. Furthermore, IAA or IBA alone showed some inhibiting effect on seminal root length, while GA3 did not produce any effect. The total number of crown roots was not affected by 10 kR, but was decreased at higher doses. On the other hand, all doses increased the number of 'stunted roots'. GA3 failed to show any effect on the number of total crown roots as well as on 'stunted roots'. IAA and IBA increased the total number of crown roots up to 20 the total number of crown roots up to 20 kR but not at higher doses. The number of 'stunted roots' showed a further increase when treated with IAA and IBA. (author)

 
 
 
 
101

Molecular Alternations Induced in Human Cells Following the Irradiation with Low Doses of Gamma Rays  

International Nuclear Information System (INIS)

Full text: We have shown previously, that human cervical carcinoma cells irradiated with low doses of gamma rays (HeLa1500) became resistant to several structurally and functionally unrelated drugs. The aim of the present study was to investigate the molecular mechanisms involved in this phenomenon. The interest was focused on the genes involved in the repair of DNA damage and apoptosis. The levels of corresponding proteins were determined by Western blot method. Our results show that the constitutive levels of the proteins involved in mismatch repair, as well as ERCC1 (which is important for excision repair), were not altered in HeLa1500 cells. The induction of apoptosis (following the treatment with cisplatin) was inhibited in HeLa1500 cells due to increased expression of BCL-2 and decreased expression of caspase 8. In conclusion, low doses of gamma rays may change the sensitivity of irradiated cells to the subsequent treatment with drugs due to the inhibition of apoptosis. (author)

102

High-speed liquid chromatography of degradation products of sodium dodecylbenzenesulfonate by gamma rays irradiation  

International Nuclear Information System (INIS)

Gamma rays irradiation-induced degradation of sodium alkylbenzenesulfonate has been mainly studied on its removal by using methylene blue method. However, the degradation processes have been little revealed because of the difficulty of analysis of the degradation products. In this study, the isolation condition of sodium dodecylbenzenesulfonate (DBS) and its degradation products by gamma rays irradiation was studied by high-speed liquid chromatography (HLC). These compounds could be isolated under the following condition; Column: Permaphase ETH (Du Pont), Column pressure: 30 kg/cm2, Mobile phase: Linear gradient from 0.01 M H2SO4-iso-propanol/n-hexane (1/99) to 0.01 M H2SO4-iso-propanol at 2%/min, Column temperature: 50 0C, Detector: UV spectrophotometer (220 nm). The degradation products which were isolated and collected by HLC were identified by using gaschromato-masspectrometer, infrared and ultraviolet spectrophotometers. Dimer, alkylphenol, hydroxyphenyl alkanoic acid, sulfophenyl alkanoic acid, hydroxysulfophenyl alkanoic acid and ring-cleavage product were detected as the degradation products in oxygenated aqueous solution of DBS. The degradation rate of DBS is recognized as first-order reaction and the primary products described above begin to be secondarily degradated at the stage of the consumption above 50% of DBS. Finally, DBS is degradated to carbon dioxide. (auth.) dioxide. (auth.)

103

Radiation-induced reduction of diuron by gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Diuron degradation efficiencies and the proposed mechanism by gamma-ray irradiation were investigated. Several factors that might affect the degradation values were further examined. The UV absorbances at 200-400 nm and diuron concentration decreased with the increase of radiation dose. When diuron initial concentration was 18.5 mg L{sup -1} and 1.0 kGy was selected as the radiation dose, diuron removal value and loss of total organic carbon were 100 and 34.1%, respectively. However, the concentration of Cl{sup -} ion increased with the increase of radiation dose. The process could be depicted by first order reaction kinetics and the reaction was mainly caused by the reaction of diuron with {center_dot}OH and e{sub aq}{sup -}. The degradation efficiency decreased with the increase of initial concentration at the same radiation dose. H{sub 2}O{sub 2}, HCO{sub 3}{sup -}, NO{sub 3}{sup -}, NO{sub 2}{sup -}, CH{sub 3}OH and humic acid as additives reduced the degradation efficiency. Furthermore, the increase of NO{sub 3}{sup -}, NO{sub 2}{sup -}, CH{sub 3}OH and humic acid would result in the decrease of the degradation values. The pH value could affect the removal efficiency and the degradation process was enhanced in acid condition. The pH value became lower with increasing radiation dose after gamma-ray irradiation.

Zhang Jibiao [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zheng Zheng [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)], E-mail: zzheng@nju.edu.cn; Zhao Tan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhao Yongfu [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Institute of Atomic Energy, Jiangsu Academy of Agriculture Sciences, Nanjing 210014 (China); Wang Lianhong; Zhong Yun; Xu Yue [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

2008-03-01

104

Radiation-induced reduction of diuron by gamma-ray irradiation  

International Nuclear Information System (INIS)

Diuron degradation efficiencies and the proposed mechanism by gamma-ray irradiation were investigated. Several factors that might affect the degradation values were further examined. The UV absorbances at 200-400 nm and diuron concentration decreased with the increase of radiation dose. When diuron initial concentration was 18.5 mg L-1 and 1.0 kGy was selected as the radiation dose, diuron removal value and loss of total organic carbon were 100 and 34.1%, respectively. However, the concentration of Cl- ion increased with the increase of radiation dose. The process could be depicted by first order reaction kinetics and the reaction was mainly caused by the reaction of diuron with OH and eaq-. The degradation efficiency decreased with the increase of initial concentration at the same radiation dose. H2O2, HCO3-, NO3-, NO2-, CH3OH and humic acid as additives reduced the degradation efficiency. Furthermore, the increase of NO3-, NO2-, CH3OH and humic acid would result in the decrease of the degradation values. The pH value could affect the removal efficiency and the degradation process was enhanced in acid condition. The pH value became lower with increasing radiation dose after gamma-ray irradiation

105

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

Energy Technology Data Exchange (ETDEWEB)

In Vitro culture of chrysanthemum variety 'Reagan Dark Splendid' was established using explants from axillary buds and ray florets. Shoots produced in vitro culture from axillary buds were irradiated with acute gamma rays of 30 Gy. While multiple shoots produced from in vitro culture of ray florets were irradiated with chronic gamma rays of 112 and 140 Gy. The irradiated shoots were then multiplied two times by single-node cuttings from M{sub 1}V{sub 1} to M{sub 1}V{sub 3}. Controls and irradiated shoots were rooted, transferred to soil in the greenhouse, and finally transplanted in the field. Observation and measurement were made at flowering time for height, number of nodes per plant and flower colour mutation frequency. Flower colour mutation frequency among the irradiated plants with 30, 112 and 140 Gy was 8.2, 9.3 and 15.3% respectively. Eleven variants were selected among the M{sub 1}V{sub 3} plants from 30 Gy dose treatment. Selected variants had flower colour varying from red, red-purple and yellow-orange. Nine variants were selected among the M{sub 1}V{sub 3} plants from 112 Gy dose treatment. Selected variants had flower colour varying from red, red-purple, purple and yellow-orange. Sixteen variants were selected from 140 Gy dose treatment. They had flower colour varying from red-purple, purple, orange-red, yellow-orange and yellow. These variants were multiplied through in vitro culture as well as by conventional cutting. They will be evaluated for their performance, stability and uniformity in the field, and for market value during the next planting season. (author)

Lamseejan, Siranut; Jompuk, Peeranuch [Kasetsart Univ., Faculty of Science, Bangkok (Thailand); Deeseepan, Surin [Maejo Univ., Office of Agricultural Research and Extension, Chiang Mai (Thailand)

2002-02-01

106

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

International Nuclear Information System (INIS)

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

107

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

International Nuclear Information System (INIS)

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

108

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

Science.gov (United States)

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.

Marin-Huachaca, Nlida Simona; Lamy-Freund, Maria Tereza; Mancini-Filho, Jorge; Delince, Henry; Villavicencio, Anna Lcia C. H.

2002-03-01

109

Morphological investigations on the tulip plants irradiated by gamma rays, 1  

International Nuclear Information System (INIS)

The present investigation was carried out in order to find out the effects of irradiation on the flower organ formation in tulip and to elucidate the mechanisms of the morphological changes anatomically. The bulbs and plants of tulips at the various growing stages, from the early stage of the flower bud differentiation (July) to the late stage of appearance of flower bud (March) were irradiated with cobalt-60 gamma rays. Dosages employed were 0.5, 1 and 3 krad at dose rates of 1.6 x 102 and 1.4 x 104 rad/hr. The results of the observation are as follows: 1. The remarkable retardations in the development of flower organs were observed by the irradiation at the stages during and immediately after the flower bud differentiation, whereas the retardations were slight at the stages of flower bud formation after the completion of the differentiation. 2. The dwarfish plants with abnormal flower were obtained after the high dose irradiation at the early stages of the differentiation, whereas the dwarfish plants with narrow petals were obtained by the irradiation at the stages after the completion of flower bud differentiation. 3. The flower with the petals deformed or breaked was obtained by the high dose irradiation at the stages during flower bud differentiation. 4. The feature in color change of a flower was also varied with the different stages irradiated, etc. (JPN)

110

The gamma-ray irradiation sensitivity and dosimetric information instability of RADFET dosimeter  

Directory of Open Access Journals (Sweden)

Full Text Available The gamma-ray irradiation sensitivity to radiation dose range from 0.5 Gy to 5 Gy and post-irradiation annealing at room and elevated temperatures have been studied for p-channel metal-oxide-semiconductor field effect transistors (also known as radiation sensitive field effect transistors or pMOS dosimeters with gate oxide thicknesses of 400 nm and 1 mm. The gate biases during the irradiation were 0 and 5 V and 5 V during the annealing. The radiation and the post-irradiation sensitivity were followed by measuring the threshold voltage shift, which was determined by using transfer characteristics in saturation and reader circuit characteristics. The dependence of threshold voltage shift DVT on absorbed radiation dose D and annealing time was assessed. The results show that there is a linear dependence between DVT and D during irradiation, so that the sensitivity can be defined as DVT/D for the investigated dose interval. The annealing of irradiated metal-oxide-semiconductor field effect transistors at different temperatures ranging from room temperature up to 150C was performed to monitor the dosimetric information loss. The results indicated that the dosimeters information is saved up to 600 hours at room temperature, whereas the annealing at 150C leads to the complete loss of dosimetric information in the same period of time. The mechanisms responsible for the threshold voltage shift during the irradiation and the later annealing have been discussed also. [Projekat Ministarstva nauke Republike Srbije, br. 17007

Pejovi? Mili? M.

2013-01-01

111

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

International Nuclear Information System (INIS)

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

112

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

International Nuclear Information System (INIS)

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

113

Effect of elongation on electrical conduction in gamma-rays irradiated low density polyethylene  

International Nuclear Information System (INIS)

Measurements of electric conductivity of gamma-rays irradiated low density polyethylene (LDPE) were conducted through uniaxial elongation by tensile stress. Inflated films with 50 ?m thickness were pre-irradiated to 2 x 105 Gy in vacuum to produce a cross-link. Uniaxial elongation was effected at 20 C with a drawing rate of 7 mm/min. Films were fixed to metallic frames after elongation to maintain tension. As a result of elongation the rate of conduction current decay was rapid, while the rates of electric conductivity and apparent conduction activation energy decreased. Current was observed in the high electric field and an assumption of space-charge-limited current was made. The suppression of microbrownian movement in amorphous parts and the increase of interfaces between amorphous and crystalline parts due to elongation were attributed to this observed behavior. (author)

114

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

International Nuclear Information System (INIS)

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

115

Gamma-ray irradiation effects on stress corrosion cracking of alloys for a high level liquid waste package  

International Nuclear Information System (INIS)

The effects of gamma-ray irradiation on stress corrosion cracking in boiling deionized water were studied on eight appropriate alloys for high level liquid waste canisters and overpacks (304 SS, 304L SS, 304EL SS, 309S SS, Incoloy 825, Inconel 600, Inconel 625, and SMA 50). Gamma-ray irradiation was shown to accelerate the intergranular stress corrosion cracking especially of sensitized 304 SS. This was assumed to have been caused by the oxidants such as O2, which were generated by the radiolysis of water. (author)

116

Response of pMOS dosemeters on gamma-ray irradiation during its re-use  

International Nuclear Information System (INIS)

Response of pMOS dosemeters during two successive irradiations with gamma-ray irradiation to a dose of 35 Gy and annealing at room and elevated temperature has been studied. The response was followed on the basis of threshold voltage shift, determined from transfer characteristics, as a function of absorbed dose or annealing time. It was shown that the threshold voltage shifts during first and second irradiation for the gate bias during irradiation of 5 and 2.5 V insignificantly differ although complete fading was not achieved after the first cycle of annealing. In order to analyse the defects formed in oxide and at the Si/SiO2 interface during irradiation and annealing, which are responsible for threshold voltage shift, midgap and charge-pumping techniques were used. It was shown that during first irradiation and annealing a dominant influence to threshold voltage shift is made by fixed oxide traps, while at the beginning of the second annealing cycle, threshold voltage shift is a consequence of both fixed oxide traps and slow switching traps. (authors)

117

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

International Nuclear Information System (INIS)

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

118

Effect of Gamma Ray Irradiation on Interlaminar Shear Strength of Glass Fiber Reinforced Plastics at 77 K  

Science.gov (United States)

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.

Nishimura, A.; Nishijima, S.; Izumi, Y.

2008-03-01

119

Reaction of nuclear graphite with oxygen under gamma-ray irradiation  

International Nuclear Information System (INIS)

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)

120

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

International Nuclear Information System (INIS)

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

 
 
 
 
121

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

International Nuclear Information System (INIS)

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

122

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

123

Stability of polyvinylpolypyrrolidone against gamma-ray irradiation in HNO3 media  

International Nuclear Information System (INIS)

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

124

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

International Nuclear Information System (INIS)

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

125

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2002-03-01

126

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

International Nuclear Information System (INIS)

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

127

The optimum methods of sodium azide treatment after gamma ray irradiation in wheat  

International Nuclear Information System (INIS)

The dormant seeds of two varieties of winter wheat were irradiated with gamma ray (200 Gy). The optimum methods, including presoaking-time of seeds, the concentration and treating-time of NaN3, were studied. It was found that the seedling height in M1 were decreased significantly and the starting-time of seed germination were delayed after seeds were presoaked. The average seedling height and the rate of emergence were reduced with the increase of concentration of treating-time of NaN3. On the basis of half of seedling height in M1, seeds presoaked for 10-12 hours and treated for 2 hours with 2 mM sodium azide were suitable for winter wheat

128

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

International Nuclear Information System (INIS)

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

129

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

Energy Technology Data Exchange (ETDEWEB)

Amounts of amino acids adsorbed onto the Au/{gamma}-Fe{sub 2}O{sub 3} composite nanoparticles synthesized by gamma-ray irradiation were measured using magnetic separation technique. Cystine and methionine, which are sulfur-containing amino acids, connected to Au by a Au-S bond could be selectively picked up by a magnet.

Kinoshita, Takuya [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)]. E-mail: t-kinoshita@stu.nucl.eng.osaka-u.ac.jp; Seino, Satoshi [Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Mizukoshi, Yoshiteru [Osaka Prefectural College of Technology, Neyagawa, Osaka 572-8572 (Japan); Otome, Yohei [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nakagawa, Takashi [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Okitsu, Kenji [Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Yamamoto, Takao A. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2005-05-15

130

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

International Nuclear Information System (INIS)

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)

131

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

International Nuclear Information System (INIS)

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

132

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

International Nuclear Information System (INIS)

In order to investigate the mechanism of extracellular polymeric substances (EPS) influencing sludge characteristics, variations of extractable EPS from municipal sewage sludge by acid/alkaline pretreatment and gamma-ray irradiation were studied. The changes in constituents of EPS were analyzed by UVvis 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. UVvis 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

133

Effect of gamma rays irradiation on ferroelectric phase transition and domain defect interaction in lead meta niobate single crystal  

Energy Technology Data Exchange (ETDEWEB)

The objective of our study is to identify the role of gamma rays to control the existing limit of ferroelectric nature of lead meta niobate (PbNb{sub 2}O{sub 6}) single crystals in terms of domain-defect interaction. The critical value of density of oxygen vacancy sites and average distance between two successive oxygen vacancies, which are responsible for ferroelectric nature in lead niobate single crystal have been calculated. The disappearance of Ferro electricity, which is associated with domain-defect interaction as well as an absence of obeying the Curie-Weiss law have been discussed in gamma rays irradiated lead meta niobate single crystal.

Yoel, Ajay, E-mail: yoelbabbi@gmail.com [Department of Physics, Hislop College, Nagpur 440001, M.S. (India); Michael, Pratik E.P. [P.G. Department of Chemistry, Hislop College, Nagpur 440001, M.S. (India); Kokate, M.V. [Department of Physics, Dr. Ambedkar College, Nagpur 440001, M.S. (India); Tabhane, V.A. [Department of Physics, University of Pune, Pune 411007, M.S. (India)

2012-02-15

134

Effect of gamma rays irradiation on ferroelectric phase transition and domain defect interaction in lead meta niobate single crystal  

International Nuclear Information System (INIS)

The objective of our study is to identify the role of gamma rays to control the existing limit of ferroelectric nature of lead meta niobate (PbNb2O6) single crystals in terms of domain-defect interaction. The critical value of density of oxygen vacancy sites and average distance between two successive oxygen vacancies, which are responsible for ferroelectric nature in lead niobate single crystal have been calculated. The disappearance of Ferro electricity, which is associated with domain-defect interaction as well as an absence of obeying the Curie-Weiss law have been discussed in gamma rays irradiated lead meta niobate single crystal.

135

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

136

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

Scientific Electronic Library Online (English)

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

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

137

Study of irradiated bothropstoxin-1 with 60Co gamma rays: immune system behavior  

International Nuclear Information System (INIS)

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 structuregnificant 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)

138

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

International Nuclear Information System (INIS)

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

139

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

International Nuclear Information System (INIS)

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)

140

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

International Nuclear Information System (INIS)

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

 
 
 
 
141

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kim, Sang Hoon; Chung, Sung Jin; Kim, Dong Sub; Kim, Jin Baek; Kang, Si Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Geung Joo [Mokpo National University, Muan (Korea, Republic of)

2009-09-15

142

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

143

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

International Nuclear Information System (INIS)

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

144

Thermally stimulated current from gamma-ray irradiated polyethylene in the high-temperature region  

International Nuclear Information System (INIS)

The polarization mechanism of alpha peak which occurs at the higher temperature than the electret-forming temperature Tsub(f), as reported in a previous paper, was re-examined. a question whether this polarization relates to the interfaces of electrodes or exists in the volume of polyethylene was made clear. In addition, the relationship between the carrier source causing the polarization and the crystallization was investigated in view of the heat treatment effect and the comparison of thermally stimulated current between the polyethylene specimen of low density and that of high density. Some knowledge on beta-peak, obtained by this experiment, is included. The specimen films were prepared by inflation method. Gold was vacuum-evaporated on the films, and the films were irradiated with 4 Mrad gamma-ray from a Co-60 source in air at dose rate from 8x104 to 6x104 rad/hr. After that, the films were held at the temperature Tsub(f), and electric field Esub(f) was applied to them for 45 minutes. The value of Esub(f) was 190 kv/cm for the high density polyethylene, and 300 kv/cm for the low density one. The polarized conditions were frozen with liquefied nitrogen. The thermally stimulated current was obtained by raising the temperature up to the melting point at rate of 20C per minute. The experiment revealed that the peak was caused by the polarization uniformly distributed within bulk. The carrier and recombination center produced by the iond recombination center produced by the ionization with gamma-ray took part in the polarization. The two site hopping model suggested that the skip distance of carrier was related to the lamella structure. (Iwakiri, K.)

145

The reduction of the dose to the lung in whole-body irradiation with cobalt-60 gamma rays  

International Nuclear Information System (INIS)

In order to reduce the exposure of the lung and oesophagus during whole-body irradiation with cobalt-60 gamma rays the dose rate delivered to the lungs and the neck is diminished by means of a filter. Because of its special shape, sternum and columna vertebralis obtain the unreduced dose. The filter is constructed for irradiation in antero-posterior direction. A fixed position of the patient is not necessary. (orig.)

146

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

International Nuclear Information System (INIS)

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

147

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-12-15

148

Electrical insulating performances of SiC materials under gamma-ray irradiation  

International Nuclear Information System (INIS)

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

149

Studying the Dosimetric Properties of GAMMA Rays Irradiated Chlorophyll Polyvinyl Alcohol  

International Nuclear Information System (INIS)

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

150

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

International Nuclear Information System (INIS)

ESR spectra of the trapped radicals in an ultra-high molecular weight polyethylene (UHMW-PE) fiber irradiated by gamma rays showed well-resolved hyperfine splitting at room temperature since the c-axis of the crystallites is aligned with the fiber direction and the radicals are trapped in crystallites. The alkyl radical (-CH2-CH-CH2-) was the major product after irradiation in vacuum and in air at room temperature. Some of the alkyl radicals converted to allyl radicals (-CH2-CH-CH=CH-) and polyenyl radicals (-CH2-CH-(CH=CH)n-CH2-) during storage in vacuum. Upon storage in air atmosphere, the alkyl radicals decayed by reaction with oxygen. Of particular interest is the very slow decay rate of the alkyl radical trapped in UHMW-PE fiber, the half-life is 26 days in vacuum, and 13 days in air at room temperature, which is about 1/30 and 1/100 of that reported for high density polyethylene (HDPE), respectively. The extremely long lifetime of the alkyl radical is supposed to be caused by the large size of crystallites in UHMW-PE fiber. The rate of radical decay was accelerated by annealing at elevated temperature.

151

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

International Nuclear Information System (INIS)

Experiment on preparation of zeolite-polyvinyl alcohol composite for absorbance materials have been done by curring using Gamma ?-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

152

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

International Nuclear Information System (INIS)

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

153

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

International Nuclear Information System (INIS)

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

154

Application of TILLING to gamma-ray-irradiated rice and use of silent mutations for tracing farm products  

International Nuclear Information System (INIS)

Mutant selection by the reverse genetic approach known as TILLING is a useful tool for gene function analysis and crop improvement. We have reported successful selection of mutants from the progeny of gamma-ray-irradiated rice plants by a modified TILLING technique. Although mutation frequency by gamma-rays is generally lower than that by chemical mutagens, gamma-rays can induce short deletion causing frameshift. Frequency of knockout mutants among the mutants selected by the SNP analysis was higher in gamma-ray irradiation than in chemical mutagen treatments. Even in gamma-ray-irradiation, most of mutations were base substitutions such as transition or transversion. Mutations in introns were also frequent. Therefore, a large proportion of mutants selected by the reverse genetic approach are mutants of silent mutations. Silent mutants are useless in gene function analysis and plant breeding, but we propose a possible use of the silent mutations as a maker for tracing farm products. Difference of cultivars, e.g., that between a high-quality cultivar and a high-yielding cultivar, can be revealed by analysis of DNA markers, but products of the same cultivar produced in different areas cannot be identified by these methods. A silent mutant line of a cultivar, which can be distinguished from the original line of the cultivar by SNP analysis, can be used as a specific line for one area. By using the dot-blot-SNP technique, grains of a Koshihikari line having a silent mutati a Koshihikari line having a silent mutation were distinguished cost-effectively from the grains of the original Koshihikari cultivar in large-scale analysis (author)

155

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

International Nuclear Information System (INIS)

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

156

Teratogenic effects of 60Co gamma rays irradiation on rat embryos  

International Nuclear Information System (INIS)

The teratogenicity of 60Co gamma rays was evaluated in Donryu rats. The results were compared with those of triterated water (HTO) for determining relative biological effectiveness (RBE) for incidence of malformations and LD50 in rats. Pregnant rats were irradiated with a 60Co source at a dose-rate of 0.5 Gy/min or 0.01 Gy/min on day 7, 8, 9, 10 or 11 of gestation with 0.8, 1.0, 1.2, 1.5, 2.0, 2.3, 2.5, 2.8 or 3.0 Gy. HTO was administered intraperitoneal injection to pregnant rats at various doses on day 7, 8, 9, 10 and 11 of gestation. The rats were sacrificed on day 18 and the offspring were examined for external and visceral malformations. Mortality, teratogenicity and effects on fetal growth were day-and dosage-dependent in both radiation groups. Congenital malformations were found most frequently in the 9-day irradiated group and followed by the 8, 11, 10 and 7-day irradiated groups. The incidence of cardiovascular anomalies was highest, especially in the day 9 of gestation group, followed by malformations in the central nervous system, craniofacial system, respiratory system, hind limbs and tail. Beta rays from HTO were found to be more effective than ? rays in inducing congenital malformations. The RBE for incidence of malformations and LD50 was between 1.3 and 1.5. These studies suggest that simulator of tritium irradiation is urgently needed to investigate the biological effects on rats to estimate the human risks,ects on rats to estimate the human risks, with respect to RBE of tritium beta rays. (author)

157

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

International Nuclear Information System (INIS)

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

158

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-10-01

159

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-03-01

160

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

Energy Technology Data Exchange (ETDEWEB)

A large scale fusion device like ITER requires high performance electric insulation materials against gamma ray and neutron irradiation, since fusion neutrons will reach superconducting magnets and activate them. Cyanate ester resin has been studied as a strong candidate for a new insulation material for fusion devices, and it has been clarified that the blended resin with epoxy has a potential to survive a design period in the radiation environment. This paper describes the results of molecular structure analysis of the blended resin, heat flux measurements by differential scanning calorimetry and the gamma ray and the fission neutron irradiation effects on interlaminar shear strength (ILSS) at 77 K. The gamma ray irradiation of 10 MGy did not change the ILSS significantly, but the neutron fluence of 1.0 x 10{sup 22} n/m{sup 2} (>0.1 MeV) with over 400 MGy degraded the ILSS. It suggests that cyanurate (triagine ring) will have a resistance against irradiation but oxazolidinon will lose the resistance after heavy irradiation.

Nishimura, Arata, E-mail: nishi-a@nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi, Gifu (Japan); Izumi, Yoshinobu [University of Fukui, Fukui (Japan); Imaizumi, Masahiro [Nipponn Kayaku Co., Ltd., Tokyo (Japan); Nishijima, Shigehiro [Osaka University, Osaka (Japan); Hemmi, Tsutomu [Japan Atomic Energy Agency, Ibaragi (Japan); Shikama, Tatsuo [Tohoku University, Ibaragi (Japan)

2011-10-15

 
 
 
 
161

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

International Nuclear Information System (INIS)

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

162

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

International Nuclear Information System (INIS)

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

163

Repair rates of DNA double-strand breaks under different doses of proton and {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

It is known that DNA double-strand breaks (DSBs), which can be induced by a variety of treatments including ionizing radiation (IR), can cause most deleterious consequences among all kinds of DNA lesions. However, it is still under debate about whether DSBs repair is equally efficient after low and high-LET radiation, especially the basic biological responses after exposure to high-LET particles. In present study, synchronous fibroblast normal Human lung fibroblast (NHLF) cells were irradiated with graded doses of proton and {gamma}-ray. Then {gamma}-H2AX foci assay was used to monitor DSBs induction and repair at 0.5, 1, 2, 4, and 18 h post irradiation. The results showed that the {gamma}-ray irradiation could produce more {gamma}-H2AX foci than proton irradiation at the same dose. However, compared to low LET radiation with {gamma}-ray, the results also showed a much slower DSBs repair rate after high LET radiation with protons, suggesting that the cellular ability to eliminate DSBs after low and high-LET ionizing radiation is quite different.

Wu Jingwen; Fu Qibin; Quan Yi; Wang Weikang; Mei Tao; Li Jia [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Yang Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Ren Xiaotang; Xue Jianming; Wang Yugang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

2012-04-01

164

Estimation of the scattered radiations in the calibration field generated by the gamma-ray irradiation system  

International Nuclear Information System (INIS)

A description follows of an operational-standard irradiation field that has been established by using gamma-ray sources installed at the Radioisotope Research Center of Osaka University. The irradiation system is composed of an irradiator mounted with 60Co (3.7 GBq) and 137Cs (11.1 GBq and 111 GBq), and a mobile exposure deck having a lead shield sandwiched with iron at the back side. The irradiator was provided with three kinds of square collimators around the irradiator beam exit. It is the purpose of the present study to utilize the irradiation system for the calibration of commercially manufactured gamma-ray dosimeters. Estimation of the scattered radiation of an irradiation field was achieved by both measurements and calculations. The absorbed dose rates due to the sources mounted in the irradiator were determined with a calibrated ionization chamber, and the contribution of scattered photons from the irradiator equipment was confirmed to be minimal by calculations with a radiation transport code. (author)

165

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

International Nuclear Information System (INIS)

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.)

166

Identification of PCB degradation products in gamma-ray irradiated solutions of PCB's in isopropanol  

International Nuclear Information System (INIS)

Destruction of polychlorinated biphenyls (PCB's) and other halogenated wastes by incineration is meeting with increasingly stronger public opposition. As a result, significant effort is being directed at the development of alternative disposal methods for the PCB's. Towards this end, the authors have explored gamma-ray irradiation as a method for detoxifying halogenated wastes. Radiolysis offers numerous advantages over incineration, including minimization of gaseous and particulate effluents and the ability to verify that the hazardous materials have been reduced to acceptable limits prior to being discharged. The authors here the results of gamma radiolysis of octachlorobiphenyl (OCB) in aerated neutral isopropanol solutions. Unlike radiolysis under alkaline conditions, where PCB's undergo stoichiometric dechlorination to free chloride and lower chlorinated biphenyls, the degradation of OCB in neutral isopropanol produces not only the expected less chlorinated PCB species, but also a series of solvent altered PCB congeners. The identity of these altered PCB compounds is reported and a mechanism is proposed for the radiolytic degradation of OCB in neutral isopropanol

167

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

International Nuclear Information System (INIS)

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

168

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

International Nuclear Information System (INIS)

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 varie for official release as new sorghum varieties to the Ministry of Agriculture. (author)

169

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

Directory of Open Access Journals (Sweden)

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

S. Human

2011-12-01

170

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

International Nuclear Information System (INIS)

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

171

Effect of gamma-ray irradiation on degradation of di(2-ethylhexyl)phthalate in polyvinyl chloride sheet.  

Science.gov (United States)

The risk assessment of di(2-ethylhexyl)phthalate (DEHP) migration from polyvinyl chloride (PVC) medical devices is an important issue for patients. The aim of this study was to determine DEHP degradation and migration from PVC sheets. To this end, the method for the simultaneous determination of DEHP and its breakdown products (mono(2-ethylhexyl)phthalate (MEHP) and phthalic acid (PA)) was improved. Their migration levels from 0 to 50 kGy gamma-ray irradiated PVC sheets were determined. DEHP migration level decreased in proportion to the dose of gamma-ray irradiation, while MEHP and PA migration levels increased. The hardness and the elastic modulus of PVC sheets were examined, but no clear relationship between DEHP migration and these parameters was observed. PMID:19394415

Ito, Rie; Miura, Naoko; Ushiro, Masaru; Kawaguchi, Migaku; Nakamura, Hiroko; Iguchi, Hirofumi; Ogino, Jun-Ichi; Oishi, Manabu; Wakui, Nobuyuki; Iwasaki, Yusuke; Saito, Koichi; Nakazawa, Hiroyuki

2009-07-01

172

A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (1)  

International Nuclear Information System (INIS)

In this study we investigated about improvement of abrasion resistance on the dental polymethylmethacrylate. That is to say, di- and tri-methacrylic acid esters and di- and tri-allyl compounds are used as cross linking monomer to coat polymethylmethacrylate, irradiated with 60Co gamma ray to bring about linking reaction and improvement in linking density, so that the abrasion resistance of the dental polymethylmethacrylate can be improved. It was found that to add di-allyl compound to unsaturated polyester, to coat the with curing catalyzer add with methylethylketoneperoxide and naphthenic acid cobalt, and to irradiate with 60Co gamma ray to enrich cross linking density after hot press processing were very effective as a treatment to improve abrasion resistance of dental polymethylmethacrylate. (author)

173

Chromatographical profiles of fluid extracts and tinctures obtained from Mikania glomerata Sprengel sterilized by gamma ray irradiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aerial parts of Mikania glomerata Sprengel, were irradiated with gamma rays in an apparatus with a Cesius-137 source in two different doses: 3.5 and 5.0 KGy. Double-blind HPLC studies on fluid extracts and tinctures prepared from the irradiated drug material were utilized to verify possible chemical changes. Extracts from the same plant (untreated) were used as standards. The results obtained showed that there was an increase in the coumarin content in the extracts obtained from irradiated pl...

Peregrino, Carlos Augusto F.; Leita?o, Suzana G.

2005-01-01

174

Hopping conduction in gold-doped germanium irradiated with 60Co gamma rays at 77 0K  

International Nuclear Information System (INIS)

Weakly compensated germanium was irradiated with gamma rays, reactor neutrons, and 4 MeV electrons. Irradiation reduced the resistivity and gave rise to hopping conduction with a variable activation energy at temperatures T0K. In the case of strongly irradiated samples the conductivity obeyed an empirical law sigma = sigma0exp(T/T0)/sup z/ over a considerable temperature range. Annealing at T> or approx. =200 0K restored the initial properties. Inhomogeneity of the doping played an important role in the appearance of hopping conduction

175

Paramagnetic defects in silicon carbide crystals irradiated with gamma-ray quanta  

International Nuclear Information System (INIS)

The results of the first observations of paramagnetic defects in SiC crystals irradiated with gamma-ray quanta are reported. Three types of defects, designated as ?1, ?2, and ?3, were detected in irradiated 4H-SiC:Al and 6H-SiC:Al crystals using electron spin resonance (ESR) measurements. All these centers have almost the same parameters of the spin-related Hamiltonian with S = 1/2 and feature an appreciable anisotropy of the g-factors. The ?1 centers are almost coaxial with the local z-axis oriented approximately along one of the directions of the Si-C bond that does not coincide with the c-axis. The ?2 and ?3 centers have a lower symmetry, although the orientation along the above bonds is clearly pronounced. The values of the largest g-factor (gz) decreases in the sequence from ?1 to ?3. The ?1 signal can be detected at temperatures of 3.5-15 K; the ?2 and ?3 signals are detectable at temperatures of 10-35 and 18-50 K, respectively. The hyperfine interaction of an unpaired electron in the ?1 center with a nucleus of the 29Si isotope is detected for certain orientations of the crystal. The ?1, ?2, and ?3 centers cease to exist at a temperature of 160 deg. C; it is concluded that the ESR signals of these centers are related to defects in the C sublattice. It is assumed that the ?1, ?2, and ?3 centers have a common origin and are related to the low-temperature (?1) and high-temperature (?2 and ?3) modifications of the same centions of the same center. The models of a defect in the form of either a carbon vacancy or a complex incorporating an Al impurity atom and a C atom that occupies the silicon site or interstice are discussed

176

Nondestructive burnup verification by gamma-ray spectroscopy of LEU silicide fuel plates irradiated in the RSG GAS multipurpose reactor  

International Nuclear Information System (INIS)

Highlights: ? Nondestructive burnup verification by gamma-ray spectroscopy of LEU silicide fuel. ? The burnup of two fuel plates irradiated in the Indonesian RSG GAS was measured. ? Cs-134/Cs-137 gamma-ray activity ratio was taken as the burnup indicator. ? Burnup verification was conducted using SRAC2006 and JENDL-3.3 based library. ? An excellent agreement between the calculated and measured values was confirmed. - Abstract: Nondestructive burnup verification by gamma-ray spectroscopy of two LEU silicide fuel plates, irradiated in the Indonesian RSG GAS multipurpose reactor, has been successfully conducted. The two fuel plates, one from the central part and another from the outer part, were extracted from the in-house manufactured, experimental silicide fuel assembly which had a declared burnup level of approximately 50% loss of U-235. As a burnup indicator, the Cs-134/Cs-137 activity ratio was selected and measured to obtain the axial distribution of relative burnup, its average values, burnup peak values and peak locations for each fuel plate, as well as the burnup difference between central and outer plates. A detail depletion analysis using SRAC2006 code system and JENDL-3.3 based library was conducted to obtain the Cs-134/Cs-137 activity ratio based on the irradiation history of the fuel element. An excellent agreement between the calculated and measured values of the activity ratio was confirmed

177

Reduction of the gamma-ray component from 252Cf fission neutron source - optimization for biological irradiations and comparison with MCNP code  

International Nuclear Information System (INIS)

Gamma-rays contribute 33% of the absorbed dose from an unfiltered 252Cf fission neutron source. To reduce this gamma-ray component and to enable radiobiological experiments at as high a dose rate as possible, Monte Carlo calculations for several filter materials (Al, Fe, Pb and concrete) have been made using MCNP neutron and photon transport code version 4a. A lead filter of thickness 4 cm was found to reduce the gamma-ray component to 6.7% of the total dose whilst reducing the neutron dose by only about 10%. Such a filter was installed at the MRC 252Cf neutron irradiation facility and dosimetric measurements were made using a TE-TE chamber and a 7LiF(Mg, Cu, P) TLD. Monte Carlo simulations agree with experimental measurements of neutron and gamma-ray doses within 6%. V79-4 Chinese hamster cells were irradiated with lead-filtered and unfiltered neutrons and also with 60Co gamma-rays at two dose rates. The survival fraction obtained for each radiation was consistent with the reduced gamma-ray dose. The relative biological effectiveness for neutrons alone, corrected for gamma-ray effects, was found to be 9.23.4 from the initial slopes and 3.10.5 at 10% survival, both relative to the acute gamma-rays. (author)

178

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

International Nuclear Information System (INIS)

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

179

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

Science.gov (United States)

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.

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

2009-07-01

180

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

 
 
 
 
181

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

International Nuclear Information System (INIS)

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

182

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

International Nuclear Information System (INIS)

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

183

Influences of Co-60 gamma-ray irradiation on electrical characteristics of Al2O3 MOS capacitors  

International Nuclear Information System (INIS)

Effects of gamma-ray irradiation on the electrical characteristics of Al2O3 MOS capacitors such as barrier height, acceptor concentration, series resistance and interface state parameters have been studied by analyzing capacitance-voltage (C-V) and conductance-voltage (G/?-V) measurements. The fabricated MOS capacitors were irradiated with gamma-rays at doses up to five grays. C-V and G/?-V measurements were recorded prior to and after irradiation at high frequency. The results show that the measured capacitance and conductance values decreased with increasing in irradiation dose and C-V and G/? curves has been shifted toward the negative voltages. Moreover, the series resistance (Rs) and density of interface states increased with increasing in irradiation dose and density of interface states (Dit) were calculated as order of 1012 eV-1cm-2 prior to and after irradiation. Due to presence and variations in the Rs values, the corrected and the measured C-V and G/?-V exhibited different behaviors. Therefore other electrical characteristics were assessed from corrected Cc characteristics. It was observed that acceptor concentration decreased with increasing in barrier height of device due to changes in interface states and diffusion potential. (author)

184

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

International Nuclear Information System (INIS)

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

185

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

DEFF Research Database (Denmark)

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

Sharma, G.; Thind, K.S.

2006-01-01

186

Detection of DNA strand breaks in barley roots after gamma-ray irradiation using the alkaline unwinding assay.  

Science.gov (United States)

The alkaline unwinding assay was applied to measure strand breaks in DNA of intact barley roots after gamma-ray irradiation without extracting DNA from the tissue. The most suitable condition for unwinding was determined to be 0.03 M NaOH containing 0.5 M NaCl for alkaline solution composition, and 15 min at 20 degrees C for unwinding time. Under this condition, DNA strand breaks were shown to be linearly increased with increasing dose, and further be rejoined during the post-irradiation incubation for 6 hr. PMID:8057269

Shikazono, N; Watanabe, H; Tanaka, A; Tano, S; Hirai, A

1994-03-01

187

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

International Nuclear Information System (INIS)

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

188

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

International Nuclear Information System (INIS)

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

189

Dense electron-positron plasmas and ultra intense gamma rays from laser-irradiated solids  

International Nuclear Information System (INIS)

In simulations of a 10 PW laser striking a solid, we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 1026 m-3 can be achieved, 7 orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of gamma rays of intensity 1022 W cm-2, potentially the most intense gamma-ray source available in the laboratory. This absorption results in a strong feedback between both pair and gamma-ray production and classical plasma physics in the new 'QED-plasma' regime. (authors)

190

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

International Nuclear Information System (INIS)

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

191

Radiation induced changes in electrical conductivity of chemical vapor deposited silicon carbides under fast neutron and gamma-ray irradiations  

International Nuclear Information System (INIS)

The radiation-induced changes in the volume electrical conductivities of chemical vapor deposited silicon carbides (CVD-SiCs) were in-site investigated by performing irradiation using 1.17 and 1.33-MeV gamma-ray and 14-MeV fast neutron beams in air and vacuum. Under gamma-ray irradiation at ionization dose rates of 3.6 and 5.9 Gy/s and irradiation temperature of approximately 300 K, the initial rapid increase in electrical conductivity; this is indicative of radiation-induced conductivity (RIC), occurred due to electronic excitation, and a more gradual increase followed up to a dose of approximately 10-50 kGy corresponding to the results in base conductivity without radiation; this is indicative of radiation-induced electrical degradation (RIED). However, the radiation-induced phenomena were not observed at irradiation temperatures above 373 K. Under neutron irradiation at a further low dose rate below approximately 2.1 Gy/s, a fast neutron flux of 9.2 x 1014 n/m2 s, and 300 K, the RIED-like behavior according to radiation-induced modification of the electrical property occurred with essentially no displacement damage, but ionizing effects (radiolysis).

192

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 esti...

Pejovi? Mom?ilo M.; Pejovi? Svetlana M.; C?, Dolic?anin Edin; Lazarevi? ?or?e

2011-01-01

193

Electron and gamma-ray irradiated NTD Si p-n structures static and dynamic parameters trade-off  

International Nuclear Information System (INIS)

The comparison of different radiation defects types influence on static and dynamic parameters trade-off of power diodes fabricated on neutron-transmutation doped silicon have been fulfilled. Various defects sets were introduced utilizing electron irradiation (E=6 MeV), gamma-ray Co 60 irradiation and electron irradiation and subsequent annealing at temperature 700 degrees centigrade. It is established that optimal trade-of between forward voltage drop and operation speed is achieved in case of electron irradiation and annealing. In this case recombination process is governed by defect with energy level near middle of forbidden gap (Ec-0.53 eV). The results obtained indicate on possibility of using these defect recombination properties for speed control in production of power fast high-voltage devices on the base of neutron-transmutation doped silicon. (authors)

194

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

International Nuclear Information System (INIS)

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

195

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

Energy Technology Data Exchange (ETDEWEB)

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).

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

196

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

International Nuclear Information System (INIS)

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. (author)

197

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

Directory of Open Access Journals (Sweden)

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.

Pejovi? Mom?ilo M.

2011-01-01

198

Strength of G-10CR and G-11CR epoxies after irradiation at 5 K by gamma rays  

International Nuclear Information System (INIS)

New data from three gamma-ray irradiations at 5 K are combined with previous results to provide complete curves of flexural and compressive strength versus dose for G-10CR and G-11CR glass-fabric-filled epoxies. Tests were made at 77 K following warm-up to 307 K. The doses required to produce 25% losses in strength were 2.1 MGy in flexure and 3.0 MGy in compression for G-10CR and 3.7 MGy for flexure and compression in G-11CR. An accompanying 10B fission fragment dose in G-10CR had little effect upon flexure strength

199

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

International Nuclear Information System (INIS)

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

200

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

International Nuclear Information System (INIS)

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

 
 
 
 
201

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

International Nuclear Information System (INIS)

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

202

Nutritional balance of pigs irradiated on the hind part with 1100 rd of 60Co gamma rays  

International Nuclear Information System (INIS)

The hind part of 10 adult miniature pigs was irradiated with 1100 rd of 60Co gamma rays. The dietary mineral (Na, K, Ca, P), nitrogen and lipid balances of the animals were studied before and 1, 3 and 5 months after irradiation. While the classical early lesion of the intestinal mucosa recovered quite satisfactorily within one or two months, a pancreatic atrophy process developed progressively which might play a major role in the nutritional state of the pigs and thus in their survival. Concerning nutritional balance, nitrogen and sodium retention were perturbed until 5 months post-irradiation; cyanocobalamin absorption remained very low. Dry and organic matter utilization recovered nearly normal values in the 3rd ou 5th month

203

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2014-05-15

204

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

International Nuclear Information System (INIS)

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

205

Chromatographical profiles of fluid extracts and tinctures obtained from Mikania glomerata Sprengel sterilized by gamma ray irradiation  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Aerial parts of Mikania glomerata Sprengel, were irradiated with gamma rays in an apparatus with a Cesius-137 source in two different doses: 3.5 and 5.0 KGy. Double-blind HPLC studies on fluid extracts and tinctures prepared from the irradiated drug material were utilized to verify possible chemical [...] changes. Extracts from the same plant (untreated) were used as standards. The results obtained showed that there was an increase in the coumarin content in the extracts obtained from irradiated plants (3.5 and 5.0 KGy) as well as a decrease in the o-coumaric acid concentration.

Carlos Augusto F., Peregrino; Suzana G., Leito.

2005-09-01

206

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

Science.gov (United States)

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

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

2012-10-01

207

Measurement and analysis of annealing factor and typical dc electronic parameters for SiGe HBT irradiated by neutrons and gamma rays in a pulsed reactor  

International Nuclear Information System (INIS)

The dc electronic parameters and annealing factor change of SiGe HBT irradiated by neutron and gamma-rays in a pulsed reactor were measured. The dc common emitter static current gain of the SiGe HBTs decreased by about 20% after the irradiation with l x l013 cm-2 neutron fluence and 257 Gy(Si) in gamma-ray total dose. The base current and the junction leakage current increased, whereas the collector current and the breakdown voltage decreased for SiGe HBT after the irradiation. Mechanisms of the radiation-induced damage to SiGe HBT are discussed. (authors)

208

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

International Nuclear Information System (INIS)

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 yih 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

209

Utilization of gamma-ray irradiation for hydrogen production from water  

International Nuclear Information System (INIS)

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 leadd that the optimal structure actually leads to enhanced hydrogen evolution from water.

210

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

International Nuclear Information System (INIS)

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

211

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

Science.gov (United States)

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

Dume, Ludovic F.; Feng, Chunfang; He, Li; Allioux, Francois-Marie; Yi, Zhifeng; Gao, Weimin; Banos, Connie; Davies, Justin B.; Kong, Lingxue

2014-12-01

212

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

International Nuclear Information System (INIS)

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

213

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-10-15

214

Radiation damage of PbWO{sub 4} crystals due to irradiation by {sup 60}Co gamma rays  

Energy Technology Data Exchange (ETDEWEB)

Radiation resistivity of large tungstate crystals PbWO{sub 4} from three suppliers has been studied for doses 10{sup 4} Gy (10{sup 6} rad) and 10{sup 5} Gy (10{sup 7} rad). Radiation resistivity was examined by the measurement of optical transmission through tungstate crystals before and after {sup 60}Co gamma-ray irradiations. The absolute degradation of transmission for 10{sup 4} and 10{sup 5} Gy doses at 480 nm wavelength of the peak emission of PbWO{sub 4} doped with La{sup 2+}, was found to be lower than 12.3% and 14.2%, respectively. The results have been also compared with radiation hardness measurements for a large volume CeF{sub 3} scintillation crystal. Complete recovery of radiation damage was observed between 10 and 15 days after irradiations.

Kozma, Peter E-mail: kozma@kozma.cz; Bajgar, Robert; Kozma, Petr

2002-09-01

215

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

International Nuclear Information System (INIS)

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

216

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

International Nuclear Information System (INIS)

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

217

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

International Nuclear Information System (INIS)

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

218

Comparative study on the degradation of UV optical fibers subjected to electron beam and gamma ray irradiation  

Science.gov (United States)

The present paper continues our previous research on the degradation of UV optical fibers under irradiation and reports, as a novelty in the filed, a comparative study on the radiation induced optical attenuation in three commercial available, UV optical fibers subjected to electron beam, gamma ray and bremsstrahlung irradiation. The purposes of these investigations were on one side to evaluate the radiation sensitivity of UV optical fibers under conditions not reported previously in the literature and, on the other side, to estimate the possible use of various types of such optical fibers for radiation detection/monitoring. The dependency of the optical attenuation at specific wavelengths was measured as a function of the optical fiber type and irradiation conditions, such as dose rate, total dose, and temperature stress applied during the irradiation. In this paper, we investigate also the behavior of H2-loaded UV optical fiber with metal coating when irradiation and heating are applied simultaneously. H2-loading of UV optical fibers proved to be a reliable mean to increase the radiation hardness in the case of UV optical fibers, and sample heating during the irradiation affect less the Al coated optical fibers than polyimide coated ones. A linear dependency of the optical attenuation on the total dose was observed for H2-loaded samples and in the case of solarisation resistant optical fibers. We suggest that a proper balance between radiation hardening and sensitivity to radiation of UV optical fibers can pave the way towards their use in radiation monitoring.

Sporea, Dan; Sporea, Adelina; Oproiu, Constantin

2013-12-01

219

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

International Nuclear Information System (INIS)

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

220

Stimulating effect of space flight factors on Artemia cysts: comparison with irradiation by gamma rays  

Energy Technology Data Exchange (ETDEWEB)

The Artemia cyst, a gastrula in dormant state, is a very suitable material to investigate the individual effects of HZE cosmic particles. Monolayers of Artemia cysts, sandwiched with nuclear emulsions, flew aboard the Soviet biosatellite Cosmos 1129. The space flight stimulated the developmental capacity expressed by higher percentages of emergence, hatching, and alive nauplii at day 4-5. A greater mean life span was reported in Artemias developed from Artemia cysts hit by the cosmic heavy ions. On Earth, Artemia cysts were exposed to 1, 10, 100, 200 and 400 Gy of gamma (gamma) rays. A stimulating effect on developmental capacity was observed for 10 Gy; the mean life span was significantly increased for this dose. These results are discussed in comparison with previous investigations performed on Earth and in space.

Gaubin, Y.; Pianezzi, B.; Gasset, G.; Plannel, H.; Kovalev, E.E.

1986-06-01

 
 
 
 
221

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

International Nuclear Information System (INIS)

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

222

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

Science.gov (United States)

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

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

2005-03-01

223

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

224

Chromosome aberrations and micronucleus in continuously irradiated mice for a low dose rate of {sup 137}Cs {gamma}-rays  

Energy Technology Data Exchange (ETDEWEB)

Delayed chromosomal instability is developed by radiation after several cell divisions in cultured rodent and human cells. The genetic instability might be related to cancer development and it has been mainly found in cultured rodent and human cells irradiated at high dose rate. It has not been well studied whether the genetic instability is induced by prolonged irradiation with low dose rate in vivo or not. Mice irradiated with 20 mGy/day for 5-8 Gy were analyzed by FISH to estimate the chromosome aberration rate and micronucleus incidence in spleen and bone marrow cells. Spleen cells in mice exposed to 8 Gy have higher incidence of monosomy and trisomy than non-exposed mice. The number of cells with 2-4 micronuclei in 10,000 scored spleen cells is also higher in 5-8 Gy exposed mice. These numerical chromosome aberrations are not induced directly by radiation exposure. These results indicate that prolonged {sup 137}Cs {gamma} ray-irradiation with low dose rates of 20 mGy/day induces delayed chromosome instability in mice. (author)

Izumi, Jun; Yanai, Takanori; Shirata, Katsutoshi; Tanaka, Kimio; Sato, Fumiaki [Inst. for Environmental Sciences, Rokkasho, Aomori (Japan)

2002-07-01

225

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

International Nuclear Information System (INIS)

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

226

Measurements of axial distributions of 60Co radioactivity in source pencils and of gamma-ray intensity in an irradiation canister  

International Nuclear Information System (INIS)

Axial distributions of redioactivity in 60Co source pencils (14 mm in diameter, 300 mm in length and a few hundred tera Bq (several thousand Ci) per pencil) were measured by use of an ionization chamber and a lead collimator. Axial distributions of gamma-ray intensity in an irradiation canister surrounded by these pencils on the circumference of 60 mm diameter were measured by a dosimeter consisting of a silicon diode connected to an electrochemical charge integrator. The relation between these distributions was investigated. A simple method of calculation assuming a linear source is found valid for describing the measured gamma-ray intensity profiles. (author)

227

Concentration of Proteins and Protein Fractions in Blood Plasma of Chickens Hatched from Eggs Irradiated with Low Level Gamma Rays  

International Nuclear Information System (INIS)

In literature there are many results which have shown that low dose radiation can stimulate many physiological processes of living organism. In our earlier paper it was shown that low dose of gamma radiation has a stimulative effect upon metabolic process in chickens hatched from eggs irradiated before incubation. This was proved by increase of body weight gain and body weight, as well as by increase of two enzymes activities in blood plasma (aspartate aminotransferase and alanine aminotransferase) which play an important role in protein metabolism. Therefore, an attempt was made to determine the effect of eggs irradiation by low dose gamma rays upon concentration of total proteins and protein fractions in the blood plasma of chickens hatched from irradiated eggs. 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. Blood samples were taken from the right jugular vein on the 1st and 3rd day, or from the wing vein on days 5 and 7 after hatching. The total proteins concentration in the blood plasma was determined by the biuret method using Boehringer Mannheim GmbH optimized kits. The protein fractions (albumin, ?1-globulin, ?2-globulin, ?- and ?-globulins) were estimated electrophoretically on Cellogel strips. The total proteins concentration was significantly decreased in blood plasma of chickens hatched from irradiated eggs on days 3 (P th day (P 2-globulin was decreased on days 1 (P th day of life. Obtained results indicate that low dose of gamma radiation has mostly inhibitory effect upon concentration of total proteins and protein fractions in the blood plasma of chickens hatched from irradiated eggs before incubation. (author)

228

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

International Nuclear Information System (INIS)

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

229

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

International Nuclear Information System (INIS)

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.

230

Identification of cellular senescence-related proteins in gamma-ray irradiated MCF7 cells  

International Nuclear Information System (INIS)

Cellular senescence, has been originally defined as proliferative arrest that occurs in normal cells after a limited number of cell divisions. It has now become regarded more broadly as a general biological program of terminal growth arrest. Senescence was originally described in normal human cells undergoing a finite number of divisions before permanent growth arrest. However, variety of stresses also induce rapid and permanent cell growth arrest. The accelerated senescence does not involve telomere shortening. Cellular senescence is believed to be essential anticarcinogenic program in normal cells. Tumor cells must avoid cellular senescence through various mechanisms. In other words, induction of cellular senescence is promising way of tumor treatment. Thus, the elucidation of the biological aspects of tumor cell senescence offers plausible approaches to the development of novel therapeutic targets to stop the growth of tumor cells. In this study, we monitored the changes of protein expression profile in MCF7 human breast cancer cells exposed to gamma-ray radiation, using two-dimensional electrophoresis. We identified biomarkers which evidently changed their expression levels in ionizing radiation-induced cellular senescence

231

New rice variety, DT38 selected successfully by gamma rays irradiation  

International Nuclear Information System (INIS)

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

232

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

International Nuclear Information System (INIS)

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

233

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

Energy Technology Data Exchange (ETDEWEB)

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 ({sup 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 M{sub 1} to M{sub 3} generations, a dosage equivalent to the LD{sub 50} observed in the M{sub 1} 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) 15 refs., 3 tabs.

Vieira, Gismar S.; Goulart, Luiz R.; Viglioni Pena, Julio C.; Fernandes, Jonas J. [Uberlandia Univ., MG (Brazil). Centro de Ciencias Biomedicas. Dept. de Agronomia

1995-12-01

234

Radiation damage of polymers studied by positron annihilation. Positron and gamma-ray irradiation effects  

International Nuclear Information System (INIS)

Positron irradiation effects on polypropylene (PP) have been studied using positron sources (22Na) during positron annihilation (PA) experiments. The irradiation effect was measured by the intensity (I3) of the long-lived component of positronium (Ps). At a low temperature of around 100 K, I3 for unirradiated PP samples increased due to a termination of the thermal motion of the -CH3 groups. However, the increase in I3 for ?-ray irradiated samples was reduced in inverse proportion to the amount of irradiation. Although no increase in I3 was observed for 1 MGy-irradiated PP with ?-rays, an increase was observed again after a 48 h irradiation by positrons emitted from 22Na. This may be due to a reconstructing of the polymer chains. (author)

235

DNA repair in modeled microgravity: Double strand break rejoining activity in human lymphocytes irradiated with {gamma}-rays  

Energy Technology Data Exchange (ETDEWEB)

Cell response to ionising radiation depends, besides on genetic and physiological features of the biological systems, on environmental conditions occurring during DNA repair. Many data showed that microgravity, experienced by astronauts during space flights or modeled on Earth, causes apoptosis, cytoskeletal alteration, cell growth inhibition, increased frequency of mutations and chromosome aberrations. In this study, we analysed the progression of the rejoining of double strand breaks (DSBs) in human peripheral blood lymphocytes (PBLs) irradiated with {gamma}-rays and incubated in static condition (1g) or in modeled microgravity (MMG). {gamma}-H2AX foci formation and disappearance, monitored during the repair incubation, showed that the kinetics of DSBs rejoining was different in the two gravity conditions. The fraction of foci-positive cells decreased slower in MMG than in 1g at 6 and 24 h after irradiation (P < 0.01) and the mean number of {gamma}-H2AX foci per nucleus was significantly higher in MMG than in 1g at the same time-points (P < 0.001). In the same samples we determined apoptotic level and the rate of DSB rejoining during post-irradiation incubation. A significant induction of apoptosis was observed in MMG at 24 h after irradiation (P < 0.001), whereas at shorter times the level of apoptosis was slightly higher in MMG respect to 1g. In accordance with the kinetics of {gamma}-H2AX foci, the slower rejoining of radiation-induced DSBs in MMG was observed by DNA fragmentation analyses during the repair incubation; the data of pulsed-field gel electrophoresis assay showed that the fraction of DNA released in the gel was significantly higher in PBL incubated in MMG after irradiation with respect to cells maintained in 1g. Our results provide evidences that MMG incubation during DNA repair delayed the rate of radiation-induced DSB rejoining, and increased, as a consequence, the genotoxic effects of ionising radiation.

Mognato, Maddalena, E-mail: maddalena.mognato@unipd.it [Dipartimento di Biologia, Universita di Padova, via U. Bassi 58 B, 35121 Padova (Italy); Girardi, Cristina; Fabris, Sonia [Dipartimento di Biologia, Universita di Padova, via U. Bassi 58 B, 35121 Padova (Italy); Celotti, Lucia [Dipartimento di Biologia, Universita di Padova, via U. Bassi 58 B, 35121 Padova (Italy); Laboratori Nazionali di Legnaro, INFN, Padova (Italy)

2009-04-26

236

Effect of gamma-ray irradiation on the unloaded animal model  

Science.gov (United States)

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.

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

237

Gamma ray irradiation induced optical band gap variations in chalcogenide glasses  

International Nuclear Information System (INIS)

In the present work ?-irradiation induced optical band gap variations (?E opt) were investigated on Ge-As-Se and Ge-As-Se-Te chalcogenide glasses. Higher doses of ?-irradiation resulted in decreased E opt, which was composition dependent. Especially, glasses with stoichiometric compositions showed different ?E opt from nonstoichiometric glasses under the same irradiation conditions. There seemed existence of a threshold E opt (TE) under the certain dose of irradiation below which ?E opt hardly occurred. Results were interpreted from viewpoint of glass structure, Chemical Bond Approach (CBA) and localized states density theory. Raman analysis supported well these discussions

238

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

International Nuclear Information System (INIS)

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

239

Assessment of the radioprotective effects of amifostine and melatonin on human lymphocytes irradiated with gamma-rays in vitro.  

Science.gov (United States)

Radioprotective effects of amifostine and melatonin as well as their ability to modulate the level of spontaneous and gamma-irradiation-induced genetic changes on human peripheral blood lymphocytes were investigated using the cytokinesis-block micronucleus (CBMN) assay and sister chromatid exchange (SCE). Parallel blood samples were pre-treated with amifostine, melatonin and their combination for 30 minutes. Negative controls were also included. After the treatment with radioprotectors, one blood sample of each experimental group was exposed to gamma-rays from a 60Co source. The radiation dose absorbed was 2 Gy. Our research confirmed the radioprotective effects of both chemicals in vitro, with no significant genotoxicity. Pre-treated irradiated blood samples showed a decrease in the total number of micronuclei (MN) and in the number of cells with more than one MN. They also showed significantly lower mean SCE values. This study shows that it is possible combine these radioprotectors by adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. However, further in vitro and clinical studies are needed to clarify their mechanisms of action and possible interactions. PMID:16832970

Kopjar, Nevenka; Mioci?, Slavica; Rami?, Snjezana; Mili?, Mirta; Viculin, Tomislav

2006-06-01

240

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

Science.gov (United States)

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

Idesaki, Akira; Uechi, Hiroki; Hakura, Yoshihiko; Kishi, Hajime

2014-05-01

 
 
 
 
241

Apparatus for gamma ray radiography  

International Nuclear Information System (INIS)

This is the standard of Japan Non-Destructive Inspection Society, NDIS 1101-79, which stipulates on the design, construction and testing method of the apparatuses for gamma ray radiography used for taking industrial radiograms. The gamma ray apparatuses stipulated in this standard are those containing sealed radioactive isotopes exceeding 100 ?Ci, which emit gamma ray. The gamma ray apparatuses are classified into three groups according to their movability. The general design conditions, the irradiation dose rate and the sealed radiation sources for the gamma ray apparatuses are stipulated. The construction of the gamma ray apparatuses must be in accordance with the notification No. 52 of the Ministry of Labor, and safety devices and collimators must be equipped. The main bodies of the gamma ray apparatuses must pass the vibration test, penetration test, impact test and shielding efficiency test. The method of each test is described. The attached equipments must be also tested. The tests according to this standard are carried out by the makers of the apparatuses. The test records must be made when the apparatuses have passed the tests, and the test certificates are attached. The limit of guarantee by the endurance test must be clearly shown. The items to be shown on the apparatuses are stipulated. (Kako, I.)

242

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

Science.gov (United States)

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

Miyahara, Makoto

2007-01-01

243

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

International Nuclear Information System (INIS)

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)

244

Photoluminescence and gamma-ray irradiation of SrAl2O4:Eu2+and Y2O3:Eu3+ phosphors  

Science.gov (United States)

Y2O3:Eu3+ phosphor is a very attractive material for use as a red phosphor in many fields. SrAl2O4:Eu2+ belongs to long lasting phosphor (LLP) and it is a useful bluish-green luminescence material, which can also be a promising candidate as a simple and easy-to-use radiation detection element for visual display of two dimensional radiation distributions. In the present study, both these two kinds of phosphors were synthesized using high temperature solid state reactions. In our work, the influence of gamma-ray irradiation on the properties of these two kinds of phosphors was studied by comparing photoluminescence, brightness and the decay curve of unirradiated and gamma-ray-irradiated samples. Conclusions from the present work can be briefly summarized as follows. In irradiated samples, the brightness is decreased without sensible change in the wavelength distribution of the luminescence spectrum and in the decay kinetic upon gamma exposure. Moreover, the emission due to Eu3+?Eu2+ conversion in Y2O3:Eu3+ phosphors was not observed in our sample after irradiation to high exposure. Also the brightness of SrAl2O4:Eu2+ phosphor turned out to decrease after the exposition to ionizing radiation while the luminescence wavelength distribution remained unchanged. The reason for the effect of gamma-ray irradiation on the properties of phosphors is also discussed in the paper.

Zhu, Chaofeng; Yang, Yunxia; Chen, Guorong; Baccaro, S.; Cecilia, A.; Falconieri, M.

2007-09-01

245

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

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

Susilawati

2009-01-01

246

Corrosion behavior of stainless steel in nitric acid solution under gamma-ray irradiation  

International Nuclear Information System (INIS)

Influence of the irradiation on the corrosion behavior of stainless steel (type 304ULC) in boiling nitric acid solution was examined by using 60Co ?-ray source. It was found from the experimental results that radiolysis products of nitric acid (NOx, HNO2) resulted from the ?-ray irradiation made the environment in the bulk solution more reducing one. On the other hand, corrosion rate of 304ULC was slightly enhanced by the irradiation, which being trivial from the engineering viewpoint. From the result of an AC impedance measurement, this corrosion enhancement was inferred as caused by an enhancement in the current across the passive film by the ?-ray irradiation on the stainless steel surfaces. (author)

247

Effects of low dose-rate gamma-ray irradiation on bio-defense systems  

International Nuclear Information System (INIS)

Preliminary experiments were undertaken to examine parameters for effects of continuous low dose-rate radiation exposure on immune cell functions. Three different strains of female and male specific pathogen-free (SPF) mice were irradiated with high dose-rate (0.9 Gy/min) ?-rays (137Cs-source) to compare distribution of splenic lymphocyte subsets and cytokine production of peritoneal exudate macrophages with those from the age-matched non-irradiated controls. Other experiments were also started to examine effects of continuous low dose-rate radiation exposure on physiological and metabolic functions. Three different strains of female specific pathogen-free (SPF) mice were irradiated with low dose-rate (21 mGy/day) ?-rays (137Cs-source) to compare the changes of body weights and amounts of diet and drinking water taken with those from age-matched non-irradiated controls. (author)

248

Relative gene expression changes in human blood lymphocytes irradiated with gamma rays  

International Nuclear Information System (INIS)

We took an effort to use quantitative-polymerase chain reaction technique to analyze gene expression patterns in irradiated human blood and to apply for dosimetry purposes. We ex vivo irradiated whole blood obtained from healthy individuals and analyzed for relative fold changes in gene expression. We demonstrated a linear dose-response induction of two genes viz. GADD45A and CDKN1A between 0.5 Gy and 4.0 Gy radiation doses. (author)

249

Autologous bone marrow transplantation following chemotherapy and irradiation in dogs with spontaneous lymphomas. [. gamma. rays  

Energy Technology Data Exchange (ETDEWEB)

Thirty dogs with spontaneous lymphomas were administered two to six cycles of chemotherapy and were randomized into 3 groups to receive 800 rads of total body irradiation and autologous bone marrow transplantation. Of 10 dogs irradiated after chemotherapy-induced remission and infused with remission marrow (group 1), 8 (80%) had successful grafts and experienced remissions lasting 62 to 1024 days. Of 9 dogs irradiated during remission and infused with remission marrow mixed with autologous tumor cells (group 2), 6 (66%) had remission lasting 15 to 45 days. Eleven dogs with progressive tumor growth (relapse) following chemotherapy were irradiated and infused with remission marrow (group 3). Tumor remission lasting 39 to 350 days was observed in 5 dogs (45%) in this group, and 6 dogs died in less than 30 days. Dogs in groups 1 to 3 had median survival times of 216, 60, and 45 days, respectively. The prolonged survival times for dogs in group 1 compared to dogs in groups 2 and 3 suggest that protocols involving irradiation and autologous marrow grafting in this model would be most effective when these protocols are applied to animals having a minimum tumor burden at the time of irradiation and when the grafting is done with tumor-free autologous marrow.

Bowles, C.A. (Hazleton Labs. of America, Vienna, VA); Bull, M.; McCormick, K.; Kadin, M.; Lucas, D.

1980-09-01

250

Measurements of potato tubers gamma-ray irradiated in nitrogen gas or carbondioxide gas  

International Nuclear Information System (INIS)

In this report the respiration of the potato tubers irradiated in nitrogen gas or carbondioxide gas was studied. Potato tubers of common Japanese variety, ''Danshaku'' were used for the examination. Potato tubers of about 2kg were put into each of Triple-Nylon bags and the bags were sealed after replacement of air in bags with nitrogen or carbondioxide gases. More than 16 hours after sealing of bags, the ?-dose (60Co) of 150 Gy or 250 Gy were given to the potato tubers in bags at the dose rate of 104 R/h. After irradiation, all bags were opened in air and amounts of CO2 released by respiration of tubers were measured with Hitachi gas chromatograph analyser Type 023. The amounts of CO2 released from the potato tubers irradiated in open air is shown in Fig. 2. The results show that there is an initial lag period of several hours, followed by a rapid increase in the respiration, after which the CO2 release was gradually decreased. Potato tubers irradiated in nitrogen gas show a similar release of CO2 on time scale to the potato tubers irradiated in open air, but the total amounts of CO2 are approximately half of those of the potato tubers irradiated in open air (Figs. 3 and 4). (J.P.N.)

251

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

International Nuclear Information System (INIS)

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

252

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

International Nuclear Information System (INIS)

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 NaNO3 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 cytokin detection of expression of murine cytokines (IFN-? 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 NaNO3, an aqueous electron scavenger, were immunogenic and the antibodies elicited by them were able to recognize the native toxin. On the other hand, when the toxin was irradiated in presence of t-butanol, a discrete reduction in antibodies levels was observed, suggesting a role of hydroxyl radicals in the modulation of immune response. Irradiated bothropstoxin-1 elicited antibodies responsive to both toxins forms, as demonstrated by Western blot. The cytokines profiles indicated that IFN-? mRNA presence appeared to be higher for mice immunized with irradiated toxin, while IL-10 mRNA presence was predominant with the antigen in its native form. These results indicate that irradiation of proteins leads to significant structural modifications, and also to a modulation of the immunological response. (author)

253

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

International Nuclear Information System (INIS)

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

254

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

International Nuclear Information System (INIS)

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

255

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

International Nuclear Information System (INIS)

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

256

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

International Nuclear Information System (INIS)

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

257

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

Science.gov (United States)

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.

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

2014-10-01

258

Flashover characteristics of poloidal field coils under gamma-ray irradiation  

International Nuclear Information System (INIS)

Flashover voltage (FOV) and other parameters which characterize the creeping discharge were measured under intense 60Co ?-ray irradiation in order to examine creeping discharge characteristics of the connecting part of the poloidal field coils of JT-60 when exposed to hard X-rays produced on runaway discharges. Alternating current voltage (50 Hz) was applied to the model coils. Results showed that FOV at an exposure rate of 1 x 106 R/h is the same as or slightly higher than that under non-irradiation; at this exposure rate, the coil insulation is not affected. FOV of sphere gas and along cylindrical bar samples were measured under the same irradiation. The value decreased for the sphere gap. FOV results at extremely high exposure rates of X-rays for these samples are also described briefly. (author)

259

Deep level defects in gamma-ray irradiated Ge doped with Pb or Sn  

International Nuclear Information System (INIS)

Deep level transient spectroscopy has been used to investigate the electrical properties of deep defect states in ?-ray irradiated Ge doped with the isoelectronic elements Pb or Sn. Three deep levels are observed in the irradiated Pb-doped Ge and two deep levels observed in the Sn-doped Ge. For the same ?ray irradiation doses, Ge crystals grown from graphite crucibles and doped with Pb or Sn show about two-thirds the total density of deep level defects observed in undoped Ge grown from synthetic quartz crucibles. All of the defect states observed were removed by a 1 hour, 2500C thermal anneal, and all but the Esub(c) - 0.39 eV state in the Pb-doped material were neutralized by exposure to a low pressure atomic hydrogen plasma. (author)

260

A new mutant for yellow mosaic virus resistance in mungbean variety SML-668 by recurrent gamma rays irradiation  

International Nuclear Information System (INIS)

Mungbean variety SML-668 is early, high yielding and large seeded but susceptible for yellow mosaic virus (YMV) disease. To develop YMV resistance in SML-668, mutation breeding programme has been under taken. Seeds of SML-668 were irradiated with 600 Gy gamma rays and planted in the field. Three thousand plants in M1 generation were harvested separately and planted in M2. Ninety lines were showing sterility and only ten lines were showing mutants for chlorophyll, small seed size, short pod length, dwarf plant type and profuse branching but there was no YMV resistant mutant. All the mutants along with normal plants of the segregating lines were harvested separately in M2. In M3 generation 2500 normal lines were planted as single plant progenies and screened for YMV resistance and did not observe any YMV resistant mutant. Hence, the normal M3 lines were made into two separate bulks and one bulk was irradiated with 500 Gy as a recurrent irradiation and another was sown as it is. In M3M1 generation a mutant showing very minor leaf symptoms for YMV and without having any pod symptoms was isolated. The mutant was purified by growing up to M3M6 generations. All the mutant plants showed very minor leaf symptoms but not in the pod. The pods and seeds were normal and also gave normal yield as compared to highly resistant check where two recessive genes controlling resistance is recessive genes controlling resistance is reported. The susceptible plants showed leaf and pod symptoms and showed severe yield losses. This mutant will be used in crossing programme to study the genetics of YMV resistance. (author)

 
 
 
 
261

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

International Nuclear Information System (INIS)

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

262

Effect of gamma-ray irradiation on raw and chemically treated cotton cellulose  

International Nuclear Information System (INIS)

The effects of gamma-irradiation on native as well as chemically modified cotton cellulose are reviewed briefly and critically. For the present purpose, the results available have been grouped into: (i) radiationneffects on native and mercerized cotton, (ii) modification of radiation effects in cottons chemically substituted with aromatic esters and unsaturated ethers, (iii) radio-protective or sensitizing action of common reagents (acids, alcohols and amines) when cotton is irradiated in their presence, and (iv) possible application of irradiation techniques in the cotton finishing field. The radiation effects have been assessed through measurements of tensile properties (load and elongation at break) as well as chemical properties (degree of polymerisa. tion, oxidation, nature of oxycelluloses). Further, the nature and behaviour of the radiation induced free radicals have been studied using ESR techniques and the ultimate effects examined in the light of the information so gathered. The results show that the effects of irradiation of cotton cellulose are depolymerization and oxidation at the molecular level, and that these can be understood in terms of the free radicals formed mainly by dehydrogenation and chain cleavage. Aromatic substitutions impart protection to cellulose from degradation, perhaps through energy transfer mechanisms. Etherification also offers protection, although the protective effects are not reflected in all the properties. Both protective and n all the properties. Both protective and sensitizing action have been noticed when irradiation is done in the presence of chemicals, depending on the nature of the reagent. The relevance of these results in radiation sterilization of celluloses, and in imparting desirable, textile properties to cotton materials through post-irradiation reactions such as grafting, cross-linking etc. are finally discussed. (author)

263

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

International Nuclear Information System (INIS)

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))

264

The effect flavobin on nucleic acids in tissues of rats irradiated with gamma rays  

International Nuclear Information System (INIS)

Flavobion /SPOFA/ is a hepatoprotective preparation containing an effective constituent - the flavonoids, namely, silybin, silydianin and silychristin, collectively referred to as silymarin. Suspension of this preparation was given p.o. by tube in a dose of 70 mg/kg, one hour before whole-body irradiation with a 5.7 Gy dose of gamma radiation (60Co). Animals were subjected to partial hepatectomy /by 30 min. after irradiation/ and examined on hour 30 after operation. Flavobion administ6ration influenced the concentration and total content of RNA and DNA in the spleen and bone marrow. However, in a target organ, liver, changes in nucleic acids less pronounced

265

Electron-microscopic studies of alveolar macrophages from gamma-ray irradiated guinea pigs  

International Nuclear Information System (INIS)

The alveolar macrophages (AM) were obtained from whole body gamma-irradiated guinea pigs (0.5 Gy and 2 Gy; 92.5 rad/min). The cell suspension contained granulocytes, lymphocytes and disintegrating epithelial and white blood cells, as well as two types of microphages: large (possessing nuclei of saddle bag-like or highly folded form) and small (with spherical or eggshaped nuclei). Eleven electronograms were presented showing all ultrastuctural changes of both small and large AM. The morphological differences between the small and large alveolar macrophages were slight. Marked changes were observed in the large AM on day 1 following 0.5 Gy irradiation: a considerable increase in dimensions of phagosomes turning in digestive vacuoles, lamellarly limited and containing osmiophilic, irregularly formed, densely or lamellarly arranged matter; folded nuclei with slightly vacuolized cytoplasm. The ultrastructural changes in the AM of sublethal dose (2 Gy) irradiated animals were stronger and regenerative processes in them were less possible. On day 30 after irradiation several damaged AM were observed with large digestive vacuoles of fine-grain content, vacuolized endoplasmic reticulum, entirely lyzed nuclear chromatin and free nuclei without cytoplasm. All observations were a convincing indication that guinea pigs AM were more radiosensitive than that obtained from rats and mice

266

Gamma ray irradiation induced degradation in ultra-thin silica layers  

International Nuclear Information System (INIS)

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

267

Effect of milling process on the electron spin resonance center formation in Pyrex glass by gamma-ray irradiation  

International Nuclear Information System (INIS)

Ball-milled Pyrex glass (Corning 7740) was irradiated by gamma-rays to a dose of 30 kGy to investigate the milling effect on the formation of paramagnetic centers with ESR. The formation efficiency of E' centers was increased markedly while that of boron oxygen hole centers (BOHCs) was suppressed by 40%. An annealing experiment showed that the milling process makes BOHCs unstable, which may be the reason for the suppression. Reduction in the ESR intensity, after etching with hydrofluoric acid, clarified that both types of center are concentrated in the near-surface region in different ratios. The milling effect on E' center formation can be explained by the formation of oxygen vacancies in the near-surface region. A similar effect has already been observed in quartz. By contrast, the suppression of BOHC formation in the bulk region needs to be described by a new mechanism. We assume that internal elastic stress induced in the milled grains suppresses BOHC formation. Internal stress in the thermally tempered glass (TTG) was relieved by breaking it to submillimeter size. The observed dependence of the BOHC formation efficiency on grain size allowed us to estimate that the suppression rate per 1 MPa is more than 0.4%, which is consistent with the milling effect assuming a stress of 100 MPa. (author)

268

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

International Nuclear Information System (INIS)

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

269

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

International Nuclear Information System (INIS)

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 ?-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

270

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

International Nuclear Information System (INIS)

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.)

271

RBE values for colo-rectal injury after caesium 137 gamma-ray and neutron irradiation  

International Nuclear Information System (INIS)

Colo-rectal damage in mice has been assessed after caesium #betta# irradiation and 3 MeV neutrons given as single doses. Several assays were used, including body weight changes, faecal deformity and lethality. Dose response curves were constructed for each assay at times ranging from 10 days to 16 months after irradiation. An initial loss of weight at 10-20 days was presumably related to epithelial denudation, but a dose-dependent weight reduction (compared with controls) persisted over the animals' life span. Mice died progressively after localised pelvic #betta# irradiation; there was no sharp demarcation between an early and late phase of lethal injury. Death resulted from intestinal stricture or stenosis. The time course for lethality was qualitatively different after neutrons, with little progression of damage between 5 and 11 months. Faecal deformity was detectable as a higher proportion of small pellets when the rectum became constricted by fibrosis. No significant faecal deformity was observed before 6 months after which time dose response curves could be obtained. The RBE for early damage (assessed at 1-3 months) was 2.2-2.7, falling to 1.7-1.9 for late damage (determined at 10-15 months) over the range of neutron doses of 7.5-12 Gy. (author)

272

Flashover characteristics along coil insulation under intense gamma-ray irradiation  

International Nuclear Information System (INIS)

The results of an experimental investigation of the surface flashover under an intense 60Co ?-ray irradiation in air are reported. The AC voltage of 50 Hz was applied to model coils under an exposure rate of 1 x 106 R/h. It is found that flashover voltages (FOV) of the model coils are not affected at this exposure rate. The FOV of sphere gap and along polymeric cylindrical bar were also measured under irradiation, showing a slight decrease for the sphere gap at an exposure rate of 4 x 105 R/h. Further, results obtained from flashover tests for DC voltage under an extremely high exposure rate of about 1013 R/h with pulsed X-ray beam show a significant decrease of FOV for the sphere gap and a slight decrease for the cylindrical bar. These results are closely related to whether partial discharges exist before the flashover or not. Considerations on the effect of the intense irradiation on the flashover characteristics are presented qualitatively. (author)

273

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

International Nuclear Information System (INIS)

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

274

Fibrinolytic characteristics of rat bone marrow extract and its variation by gamma-ray irradiation  

International Nuclear Information System (INIS)

The purpose of this investigation is to study the enzymatic properties of rat bone marrow extract which exhibits high fibrinolytic activity, and to observe whether or not the activity is influenced by the whole body irradiation. The results were obtained as follows: 1) A high fibrin degradation activity was extracted with 2M KSCN from rat bone marrow, but failed with 0.15M NaCl or 0.88M sucrose. 2) The activity was clearly demonstrated on plasminogen-free fibrin plates, whereas it was not shown on plasminogen-rich fibrin plates. Assumingly, the activity differs with plasminogen activator. 3) The activity was strongly inhibited with STI as well as DFP, while it was bearly inhibited with TLCK, t-AMCHA and Aprotinin. On the bases of above results, the factor extracted from rat bone marrow by us appears to be identical or similar to the factor in the conventional rat spleen recently found by Okamoto and Nagamatsu. 4) The activity of rat bone marrow extract was remarkably decreased by ?-ray whole body irradiation, and the observed tendency was well correlated with the irradiation-induced bone marrow damage. The activity is, therefore, implicated to be a bone marrow cell origin. (author)

275

Effects of 60Co gamma rays on Gerbera jamesonii plantlets irradiated in vitro  

International Nuclear Information System (INIS)

The aim of this work was to determine the direct inhibitory effects of 60 ?-rays on plantlets and to control them in a future program of experimental mutagenesis. Gerbera jamesonii plantlets were irradiated in vitro using two sources of 60Co ?-rays. The following variables were tested: dose rate, total dose, irradiation of growth medium, time interval between the exposure to ?-rays and the subdivision and transfer to fresh medium, and dose fractionation. These variables were evaluated using regeneration rate of new shoots, callus production, and plantlet growth rate (fresh weight). The optimal dose ranged around 50 Gy at a low dose rate (8.4 Gy h-1) and 30 Gy at high dose rate (600 Gy h-1). These conditions assured minimal development of callus and 50% of the normal multiplication rate. The ?-irradiation may be done during a 1-week interval before or after transfer on fresh medium, without causing any additional effects. Interrupted doses (3 x 10 Gy at 48-h intervals) caused less important inhibitory effects than a single dose (30 Gy), but the intensity of the reaction varied according to clone and the measured parameter. The clone 'Duplex' reacted favourably; this type of treatment ensured better callus and plantlet growth and a higher rate of regeneration. In the case of 'Mardi Gras', which is less sensitive to fractionated doses, only the weight of the plantlets was significantly less reducedtly less reduced

276

Augmentation of NO production and cytolytic activity of M{phi} obtained from mice irradiated with a low dose of {gamma}-rays  

Energy Technology Data Exchange (ETDEWEB)

The activation of macrophages (M{phi}) by low-dose irradiation (4cGy) was examined. The irradiated M{phi} were obtained from mice exposed to a low dose of {gamma}-rays. The addition of excess irradiated M{phi} suppressed more the concanavalin A-induced proliferation of splenocytes than that of unirradiated M{phi}. This was attributed to large nitric oxide (NO) production from irradiated M{phi}. In addition, low-dose irradiation augmented NO production and glucose consumption in M{phi} treated with interferon-{gamma} alone or interferon-{gamma}/lipopolysaccharide. Furthermore, low-dose-irradiated M{phi} showed a higher cytolytic activity against P-815 mastocytoma cells than unirradiated M{phi}, indicating that the NO production was involved in the activity. On the other hand, the M{phi} irradiated with a low dose in vitro did not enhance the NO production. These findings suggest that whole-body irradiation with a low dose of {gamma}-rays activates M{phi} indirectly and consequently enhances NO production from M{phi}, by which the self-defense systems such as the tumoricidal activity will be augmented. (author).

Ibuki, Yuko; Goto, Rensuke [University of Shizuoka (Japan)

1995-09-01

277

Enhancement of hydrogen evolution yield from water dispersing nanoparticles irradiated with gamma-ray  

International Nuclear Information System (INIS)

Hydrogen gas evolution from water dispersing nanoparticles induced by 60Co ?-ray irradiation was studied. Nanoparticles of TiO2 and Al2O3 with average sizes of 7-33nm supplied from several suppliers were examined. It was indicated that reactions enhancing the hydrogen evolution proceed on particle's surface. It was implied that the yield depends on size of agglomerated particle regardless of their primary particle size and chemical species. Reactions that enhance the hydrogen yields were discussed, and radiolysis process was concluded dominant in the total enhancement mechanism. (author)

278

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

International Nuclear Information System (INIS)

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

279

Tissue-air ratios for whole body irradiation with cobalt 60 gamma rays  

International Nuclear Information System (INIS)

Total body irradiation with 60Co ?-rays is used in the treatment of acute leukemia. Calculations of treatment time may require knowledge of the dose at the mid-line of the body. A formula is derived for the calculation of tissue-air ratios (TAR) for equivalent square fields. Measurements of dose distributions have been made using an Alderson phantom, and the results used to obtain TARs at various depths along lateral body diameters in the abdomen below the umbilicus, across the mid-line of the pelvis, and in the lungs. Comparison of the calculated and measured values of TARs establishes the validity of the formula. (author)

280

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-06-15

 
 
 
 
281

EPR Study of the Activation of Antioxidants in PP Irradiated with Gamma Rays  

International Nuclear Information System (INIS)

The behavior of different formulations of Polypropylene (PP) with stabilizers such as buthyl-hydroxy-toluene (BHT), Chimasorb 944 (Hals) (CHIM), both from Ciba, and a copolymer of styrene-butadiene-styrene (SBS) were studied using electron paramagnetic resonance (EPR). In all the cases but the sample of PP-Hals, a characteristic specta for PP irradiated in air in the recently-irradiated condition was obtained. The lineshape of the signal was changed to that of a pure PP EPR signal as time elapsed and the alkyl radical concentration decreased up to its total disappearance. At that stage, the polyenil radical signal could be visualized better. The total free radical concentration decayed until approximately 800 hours in the PP-Hals and until around 2000 hours in all other cases. At those points, the total free radical concentrations began to increase in all the cases, except in the PP-BHT case. The lineshape was transformed into the lineshape of the Chimasorb radical in all the cases, except for the PP-BHT. In this last case, the EPR signal was not detectable. The BHT and the SBS diluted the free radical concentrations, being them smaller when they are present. The observed behavior in all the samples is consistent with the activation of the Chimasorb radical by gamma radiation

282

On-site gamma-ray spectroscopic measurements of fission gas release in irradiated nuclear fuel.  

Science.gov (United States)

An experimental, non-destructive in-pool, method for measuring fission gas release (FGR) in irradiated nuclear fuel has been developed. Using the method, a significant number of experiments have been performed in-pool at several nuclear power plants of the BWR type. The method utilises the 514 keV gamma-radiation from the gaseous fission product (85)Kr captured in the fuel rod plenum volume. A submergible measuring device (LOKET) consisting of an HPGe-detector and a collimator system was utilised allowing for single rod measurements on virtually all types of BWR fuel. A FGR database covering a wide range of burn-ups (up to average rod burn-up well above 60 MWd/kgU), irradiation history, fuel rod position in cross section and fuel designs has been compiled and used for computer code benchmarking, fuel performance analysis and feedback to reactor operators. Measurements clearly indicate the low FGR in more modern fuel designs in comparison to older fuel types. PMID:16949295

Matsson, I; Grapengiesser, B; Andersson, B

2007-01-01

283

Thermoluminesence of gamma rays irradiated CaSO4 nanorods doped with different elements  

Science.gov (United States)

Nanorods of calcium sulfate (CaSO4) activated by Ag, Cu, Dy, Eu and Tb were synthesized by the co-precipitation technique. They were irradiated by ?-rays in a wide range of exposures and studied for their thermoluminesence (TL) properties. The as-synthesized samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL) emission spectra. SEM images show that the samples doped with rare earths elements (i.e. Dy, Eu and Tb) have thinner nanorods than the other samples, while XRD pattern shows a complete crystalline structures in a monoclinic phase. The TL glow curves of these samples show two components. The first one include low temperature glow peaks at around 125 C, while the second component shows high temperature peaks in the range 230-270 C. These glow peaks diver from sample to sample by their TL intensity. The TL results are promising, particularly that of Tb and Eu. Tb doped sample is found to be a highly TL sensitive with a prominent glow peak at around 270 C, while Eu has created very active, high dense electron traps. The later shows quite linear response in the whole studied exposures i.e. 10 Gy-10 kGy. These results show that Eu or Tb doped CaSO4 nanorods might be proper candidates as dosimeters for high doses of ionizing radiations used in irradiation of foods and seeds.

Salah, Numan

2015-01-01

284

Gamma-ray astronomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 pape...

Pohl, Martin

2001-01-01

285

Gamma ray generator  

Science.gov (United States)

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

Firestone, Richard B; Reijonen, Jani

2014-05-27

286

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

International Nuclear Information System (INIS)

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

287

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

International Nuclear Information System (INIS)

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

288

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

289

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

Science.gov (United States)

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.

Lim, Youn-Mook; An, Sung-Jun; Kim, Hae-Kyoung; Kim, Yun-Hye; Youn, Min-Ho; Gwon, Hui-Jeong; Shin, Junhwa; Nho, Young-Chang

2009-07-01

290

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

International Nuclear Information System (INIS)

Low molecular weight chitosan (LMWC) powder and oligochitosan solution were prepared by ?-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)

291

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

International Nuclear Information System (INIS)

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)

292

The influence of irradiation with 60Co-gamma ray on rabbit's submandibular gland  

International Nuclear Information System (INIS)

Fractionated irradiation of 7000 rads with 60Co-? ray was given to the submandibular glands of rabbits for continuous 2 days. After exposure, morphological changes were examined by sialography and angiography, functional changes were examined with sup(99m)TcO4- and 131I-albumin, and pathohistological changes and changes of secreted particles were totally studied for 56 days. Until the 7th day after the irradiation, the duct system was dilated, snake-like flow of the vascular system was markedly observed, and inflammatory changes were found. Until the 14th day, split of the duct system, decrease of the number of the vascular system and mild inflammatory changes were continuously observed. After the 28th day, the findings were almost same as those of healthy control group. The examination with simultaneous administration of sup(99m)TcO4- and 131I-albumin revealed that the function of the glands and the blood flow volume increased at the 1st day after the exposure, and that the function of the glands continued to be enhanced. However, poor change was found in both from the 7th day and the function was almost same as that of the control group after the 14th day. Although inflamatory finding was slightly found until the 7th day, the finding was almost same as that of the control group after the 14th day. Although the number of the particles rapidly dropped after the exposure, it gradually recover after the exposure, it gradually recovered from the 7th day, and the finding was almost same as that of the control group after the 28th day. Total comparison of the above findings revealed that both functional and morphological changes in the submandibular glands appeared in early period after the exposure, but that the changes recovered relatively earlier in the functional aspect. (Kumagai, S.)

293

Temporal variation of excess mortality rate from solid tumors in mice irradiated at various ages with gamma rays  

International Nuclear Information System (INIS)

The influence of age at the time of irradiation on the lifetime risk for excess mortality from solid tumors, and on the temporal pattern of variation in the excess mortality rate, was analyzed using data obtained from a study of female B6C3F1 mice, which was conducted at the National Institute of. Radiological Sciences, Chiba, Japan. Mice were irradiated with 1.9-Gy gamma rays at day 17 in intra-uterine age, or day 0, 7, 35, 105 or 365 in postnatal age. Control and irradiated mice were allowed to live out their entire life span under a specific pathogen-free condition. The primary cause of death for each mouse was determined by macroscopic and microscopic examination. The lifetime excess mortality from solid tumors was apparently higher in the mice irradiated during the neonatal to puberty period than in the mice irradiated during the intra-uterine or adult period. The median of time for manifestation of lifetime excess mortality since irradiation was shortest among mice exposed at 365 days of age and longest among mice exposed at 17 days of intra-uterine age. The excess mortality rate at any attained age was not independent of the age at irradiation. The excess mortality rate increased with increasing age, and the excess relative risk decreased with increasing age. The temporal variations of the excess mortality rate and background mortality rate were analyzed using the additive multi-stage model, which includes the assumptions that radiation-related carcie assumptions that radiation-related carcinogenesis superimposes on background carcinogenesis, and that both radiation-related and background carcinogenesis involve multiple stages. The results of the analysis strongly suggested that the number of stages for manifestation of radiation-related carcinogenesis was less than that in background carcinogenesis for various types of solid tumors, and that the majority of stages were common in both radiation-related and background carcinogenesis. The additive multi-stage model well described the observed findings on the length of the latent period and temporal variations of the excess mortality rate and excess relative risk. It should be stressed that the magnitude of the lifetime risk was not only determined by a decrease in the number of hits for carcinogenesis but was also determined by another parameter which decides the initial value of excess mortality rate. Furthermore, we estimated the rate of decrease in the number of remaining hits for carcinogenesis, and it was found that the rate of decrease in the number of remaining hits was higher in several irradiated groups than that in the background carcinogenesis. However, radiation-induced genomic instability and/or delayed mutation may be of secondary importance when radiation was delivered promptly, because the present analysis revealed that the major action of radiation took place soon after irradiation, as one or more hits for transitions of stages for carcinogenesis. (author)

294

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

International Nuclear Information System (INIS)

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

295

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

International Nuclear Information System (INIS)

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

296

Genetic effects of gamma ray and ion beam irradiation on plants  

International Nuclear Information System (INIS)

This study was aimed to clarify the optimum conditions to induce a mutation in Setaria italica (L.) using gamma irradiation and selection of S.italica mutants as to agricultural phenotype was conducted. Ten kinds of rice species assigned into temperate Japan type, tropical Japan type and India type were used as the subjects for investigation of differences in sensitivity to ion-beam among species. In addition, the optimum dose to induce a gene mutation in BY-2 cell was determined. In either test groups, the number of subjects that reached the ear formation was 2/3 of inoculated number in either test groups. Since there was no correlation between the number of subjects leading to ear formation and radiation dose, a dose less than 100 Gy was thought to have no lethal effects on young seedlings on the day 2 after germination. It was indicated that growing damages such as lowering of ear length and fertility did not affect production of S.italica and rice mutants. The incidence of xantha mutation was high in S. italica, but it was 1/5 -1/10 of that of albino mutant in the rice, indicating that such differences in mutation rate might be due to the differences of the number of related genes, but not the high rate of mutation per gene. (M.N.)

297

Effects of gamma-ray irradiation on dislocations in sodium nitrate single crystals  

International Nuclear Information System (INIS)

The topography of the etch pits formed on the (100) cleavage surfaces of unirradiated and irradiated NaNO3 single crystals has been studied. The principal etch pit alignments are consistent with dislocation families of the type (100) [011], (211) [011], and (111) [011]. The pit density increases from 1.4 (+-0.2) x 104/cm2 at zero dose to 7.3 (+-0.2) x 105/cm2 at 5.0 x 108 rad. With increasing dose the pit density distribution narrows and clusters at 1.0 x 106 pits/cm2 at doses above 5.0 x 108 rad. Above this dose radiolytic-induced micro bumps or structures are observed that precede the onset of radiolytic decomposition that is visible at 2.5 x 09 rad. These asymmetric structures appear to nucleate at the same sites as the chemically created etch pits and are aligned in the same principal directions. These observations indicate that dislocations are important sites for nucleating radiation induced decomposition and internal radiolytic gas generation. 12 references, 9 figures, 1 table

298

Effects of stereoregularity on molecular parameters of polyacrylonitrile polymerized by gamma-ray irradiation  

International Nuclear Information System (INIS)

Polyacrylonitrile (referred to as ?-PAN) was prepared by ?-ray irradiation on an acrylonitrile-urea canal complex at -78 deg C. The pentad tacticity was evaluated from 13C NMR spectra according to a method proposed by Kamide et al. The content of a mmmm sequence (m; meso) for ?-PAN was 0.37 0.02 over a wide range of molecular weight, which was about 4.4 times larger than that for PAN, prepared by conventional redox polymerization (R-PAN). Light scattering and solution viscosity were measured in dimethyl sulfoxide (DMSO), 57 - 67 wt% aq nitric acid at 25 deg C. By extrapolation of the second virial coefficient A2 to zero 56.5 wt% aq nitric acid was expected to be a Flory theta solvent at 25 deg C. Mark-Houwink-Sakurada equations and empirical relations between the radius of gyration 2>Z1/2 and M-barw were determined in various solvents. The unperturbed chain dimension A was determined by four methods. In DMSO ?-PAN has larger A than R-PAN. The conformation parameter ? was 2.6 - 2.8 for ?-PAN, which is some 35 % larger than the expected value when simple steric hindrance due to the side chain group is considered. Unexpectedly larger conformation parameters ? for ?- and R-PAN were interpreted by considering the rigidity of the chain due to intra-interactions between neighbouring CN groups in meso-sequence. (author)

299

Effects of absorbed dose rate, irradiation temperature and post-irradiation temperature on the gamma ray response of red Perspex dosimeters  

International Nuclear Information System (INIS)

The influences of irradiation temperature and gamma radiation dose rate on the response of red 4034 Perspex dosimeters have been reported in the literature to be of relatively minor consequence, particularly for irradiations at up to a temperature of 40 deg. C and at absorbed dose rates of the order of 7 kGyh-1 (?2 Gys-1). The present study shows this to be true; however, if there are marked differences in the temperature (22 deg. C to 50 deg. C) during extended storage periods (up to 16 hours) after irradiation, there is a tendency to overestimate an unknown dose administered at the elevated temperature, as a result of using a calibration made at an ambient lower temperature (e.g. 22 deg. C). The present study of dose rate effects also shows that there is a pronounced tendency to overestimate an unknown gamma ray dose administered at a relatively low dose rate (3 and 7 kGyh-1) as a result of using a calibration made at a considerably higher dose rate (e.g. 31 kGyh-1), even when the temperature of irradiation and storage is controlled at 22 deg. C. (author). 14 refs, 13 figs

300

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

International Nuclear Information System (INIS)

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

 
 
 
 
301

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

Energy Technology Data Exchange (ETDEWEB)

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

NONE

2011-07-01

302

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

International Nuclear Information System (INIS)

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

303

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

Science.gov (United States)

This study was conducted to compare effects of electron beam (EB) and gamma ray (GR) treatments at doses of 25, 50 and 75 kGy on ruminal degradation kinetics of crude protein (CP), amino acid (AA), and in vitro digestibility of cottonseed meal (CSM). Ionizing radiations of EB and GR had significant effects (P0.05). Irradiation processing caused decrement in AA degradation after 16 h of ruminal incubation (Pdigestibility of CSM numerically. This study showed that EB could cause CP and AA bypass rumen as well as GR. Therefore, ionizing irradiation processing can be used as an efficient method in improving nutritional value of CSM.

Ghanbari, F.; Ghoorchi, T.; Shawrang, P.; Mansouri, H.; Torbati-Nejad, N. M.

2012-06-01

304

Dense Electron-Positron Plasmas and Ultra-Intense Bursts of Gamma-Rays from Laser-Irradiated Solids  

CERN Document Server

In simulations of a 10PW laser striking a solid we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 10^26/m^3 is achieved, seven orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of gamma-rays of intensity 10^22W/cm^2, potentially the most intense gamma-ray source available in the laboratory. This absorption results in a strong feedback between both pair and gamma-ray production and classical plasma physics in the new `QED-plasma' regime.

Ridgers, C P; Duclous, R; Kirk, J G; Bennett, K; Arber, T D; Robinson, A P L; Bell, A R

2012-01-01

305

Activation of immune functions via induction of glutathione of lymphocytes by low-dose, whole-body irradiation with gamma-rays  

International Nuclear Information System (INIS)

Complete text of publication follows. We have recently found that low doses of radiation, unlike higher doses, do not always cause a decrease of cellular glutathione, but they can increase it, leading to an elevation of Con A-induced proliferation of splenocytes. In this study, we first examined whether the increase of glutathione level induced by low-dose gamma-ray irradiation is involved in the appearance of enhanced natural killer (NK) activity and antibody-dependent cellular cytotoxicity (ADCC), leading to delayed tumor growth in Ehrlich solid tumor (EST)-bearing mice. NK activity in ICR mouse splenocytes was significantly increased from 4 h to 6 h after a single whole-body gamma-ray irradiation at 0.5 Gy, and thereafter decreased almost to the zero-time level by 24 h post-irradiation. ADCC was also increased significantly in a similar way. Reduced glutathione exogenously added to splenocytes obtained from normal mice enhanced both NK activity and ADCC in a dose-dependent manner. The inhibitory effect of the radiation on tumor growth was then examined in EST-bearing mice. Repeated low-dose irradiation (0.5 Gy, four times, before and within an early time after the inoculation) significantly delayed the tumor growth. Finally, the effect of single low-dose (0.5 Gy), whole-body gamma-ray irradiation on immune balance (Th1/Th2) was examined in order to elucidate the mechanism underlying the anti-tumor immunity. Recent studies indicate that Th1/Th2 balance plays an impondicate that Th1/Th2 balance plays an important role in the immune responses involved in anti-tumor immunity. The activity of NK is hallmarks of cell-mediated immunity, and play key roles in anti-tumor immunity. The percentage of B cells in blood lymphocytes was selectively decreased after the radiation, concomitantly with an increase in that of helper T cell population, favoring Th1 polarization. The IFN-gamma level in splenocyte culture prepared from EST-bearing mice was significantly increased 48 h after the radiation, though the level of IL-4 was unchanged. IL-12 secretion from macrophages was also enhanced by the radiation. In conclusion, it has been shown that the anti-tumor effect of 0.5 Gy gamma- ray irradiation is induced by the enhancement of cell-mediated immunity via Th1 polarization. From the viewpoint of others, it may be suggested that Th1-dominant polarization following irradiation is mediated by a decrease of B cell population and enhance the activities of tumoricidal effector cells, leading to a delay of tumor growth in EST-bearing mice.

306

TL dosimetry using extracted and cleaned sand to measure gamma-ray dose rate at a liquid sewage sludge irradiation facility  

Science.gov (United States)

In an earlier study, we investigated the thermoluminescence (TL) properties of the sand collected from sewage sludge, after various extensive cleaning procedures and irradiation of gamma rays under controlled conditions in the laboratory. In the present investigation, the sand separated from the irradiated sludge was used to estimate the radiation processing absorbed dose to sludge at the sludge hygienisation research irradiator (SHRI), Baroda. Although, the relative TL sensitivity of H 2O 2- and HF-treated sludge sand samples was 4.00% and 0.07%, respectively, of that of LiF TLD-100, a well known TL phosphor used in radiation dosimetry, they were quite useful for dosimetry of the liquid sludge irradiator, when using TL calibrations of sand from sludge collected from sludge irradiator inlet. A useful dose range for such calibration is 0.3-4 kGy. A dose-vs-TL response calibration curve was plotted for the 220C TL glow peak for H 2O 2- and HF-treated sludge sand samples collected at the sludge irradiator inlet from an unirradiated batch, in order to estimate dose absorbed in the corresponding batch of the irradiated sludge collected at the sludge irradiator outlet. Using this method, the absorbed dose rate delivered to the sludge during irradiation at SHRI was estimated to be 0.70 0.02 kGy per hour. The paper also reports results of a dosimetry intercomparison for H 2O 2- and HF-treated sand samples, and LiF TLD-100 TL phosphor. The estimated gamma ray doses were nearly the same for all the three systems irradiated for the same exposure times.

Benny, P. G.; Bhatt, B. C.; Shah, M. R.

1997-03-01

307

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

International Nuclear Information System (INIS)

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

308

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

309

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

International Nuclear Information System (INIS)

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

310

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

International Nuclear Information System (INIS)

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

311

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

2002-05-01

312

Enhanced micronucleus formation in the descendants of {gamma}-ray-irradiated tobacco cells: Evidence for radiation-induced genomic instability in plant cells  

Energy Technology Data Exchange (ETDEWEB)

Ionizing radiation-induced genomic instability has been documented in various end points such as chromosomal aberrations and mutations, which arises in the descendants of irradiated mammalian or yeast cells many generations after the initial insult. This study aimed at addressing radiation-induced genomic instability in higher plant tobacco cells. We thus investigated micronucleus (MN) formation and cell proliferation in tobacco cells irradiated with {gamma}-rays and their descendants. In {gamma}-irradiated cells, cell cycle was arrested at G{sub 2}/M phase at around 24 h post-irradiation but released afterward. In contrast, MN frequency peaked at 48 h post-irradiation. Almost half of 40 Gy-irradiated cells had MN at 48 h post-irradiation, but proliferated as actively as sham-irradiated cells up to 120 h post-irradiation. Moreover, the descendants that have undergone at least 22 generations after irradiation still showed a two-fold MN frequency compared to sham-irradiated cells. This is the direct evidence for radiation-induced genomic instability in tobacco cells.

Yokota, Yuichiro, E-mail: yokota.yuichiro@jaea.go.jp [Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Funayama, Tomoo; Hase, Yoshihiro [Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Hamada, Nobuyuki [Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado-kita, Komae, Tokyo 201-8511 (Japan); Kobayashi, Yasuhiko; Tanaka, Atsushi; Narumi, Issay [Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

2010-09-10

313

Gamma-ray irradiation of a boreal forest ecosystem: the Field Irradiator-Gamma (FIG) facility and research programs  

International Nuclear Information System (INIS)

A long-term radiation ecology research project called Field Irradiator-Gamma (FIG) was begun 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 object of the project is to study the ecological effects on a mixed boreal forest ecosystem of continuous exposure to a gradient of gamma radiation. The gradient ranges from 0 to 460 000 times the natural background radiation level. This paper describes the forest, the gamma irradiator and its radiation field, and the research programs

314

Radiobiological effect of heparin in Swiss mice human amnion cells and E. Coli B/r irradiated with Co/sup 60/. gamma. -rays  

Energy Technology Data Exchange (ETDEWEB)

The radiobiological action of Heparin was investigated using the test systems E. Coli B/r, Human Amnion (HA) cells and Swiss mice. The Heparin treatment of these systems effected following changes in their response towards irradiation with Co/sup 60/ ..gamma..-rays: (a) more sensitization of E. coli B/r in hypoxic than in oxic condition, (b) no significant modification for HA cells in oxic condition but their sensitization under hypoxia, (c) larger recovery of anodic electrophoretic mobility of irradiated HA cells, (d) increased life span and smaller reduction in the splenic and thymus weights of irradiated Swiss mice. It seems, therefore, that Heparin, a natural molecule of animal world, possesses the potentiality to modify radiation response of living systems and may find useful application in radiation therapy.

Chaubal, K.A.; Godbole, C.S.

1983-12-01

315

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

International Nuclear Information System (INIS)

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)

316

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-04-24

317

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

International Nuclear Information System (INIS)

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 substanminutes 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 also led to a considerable decrease in the frequency of radiation induced MN, other mechanisms such as induction of cell cycle delay and hence influencing DNA repair, might be involved in radioprotection by amifostine

318

ESR study of temperature dependence of colour centers in. gamma. -ray irradiated fluoride glasses. [ZrF sub 4 -BaF sub 2 -LaF sub 3 -AlF sub 3 -NaF  

Energy Technology Data Exchange (ETDEWEB)

{gamma}-ray irradiated ZBLAN fluoride glasses at liquid-nitrogen temperature and room temperature have been studied by ESR. Irradiation-induced point defects are characterized as F{sub 2}{sup -}, F{sup 0}, Zr{sup 3+}, central line and one type of center assigned as a hole trapped on an oxygen impurity. Isochronal annealing experiments show that these centers are unstable at high temperature. {gamma}-ray irradiation at room temperature produces a prominent absorption band in the ultraviolet region. (orig.).

Li Ruihua; Wang Haobing; Gan Fuxi (Shanghai Inst. of Optics and Fine Mechanics, Academia Sinica (China))

1992-01-01

319

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 mutat...

Badigannavar And Suvendu Mondal, Anand M.

2010-01-01

320

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

International Nuclear Information System (INIS)

The main purpose of this work was to make a contribution to the study of the chemical effects of the (n,?) reaction on copper chelate. The influence of some factors such as pre-heating and pre-irradiation with 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)

 
 
 
 
321

Caffeine sensitization of cultured mammalian cells and human lymphocytes irradiated with gamma rays and fast neutrons: a study of relative biological effectiveness in relation to cellular repair  

International Nuclear Information System (INIS)

The sensitizing effects of caffeine were studied in baby hamster kidney (BHK-21) cells and human lymphocytes following irradiation with gamma rays and fast neutrons. Caffeine sensitization occurred only when log-phase BHK cells and mitogen-stimulated lymphocytes were exposed to the two radiations. Noncycling (confluent) cells of BHK resulted in a shouldered survival curve following gamma irradiation while a biphasic curve was obtained with the log-phase cells. Survival in the case of lymphocytes was estimated by measurement of [3H]thymidine uptake. The relative biological effectiveness (RBE) of fast neutrons was found to be greater at survival levels corresponding to the resistant portions of the survival curves (shoulder or resistant tail). In both cell types, no reduction in RBE was observed when caffeine was present, because caffeine affected both gamma and neutron survival by the same proportion

322

Evaluation of leukocyte number by using an automated blood cell counter and a traditional hematological method in animals irradiated with gamma rays  

International Nuclear Information System (INIS)

Female mice were irradiated with a single whole-body dose of 7 Gy of gamma rays. Leukocyte numbers were monitored in the peripheral blood using automated blood cell counter Coulter counter (CC) and a traditional hematological method with a light microscope in the Buerker chamber. Reticulocyte numbers, RNA blood concentration, spleen weight and morphological changes in spleen and bone marrow were also studied. In the period between 15th-19th days after irradiation the numbers of leukocytes obtained by CC counting were manifold higher than those obtained by microscope counting. Since this period is characterized by a steep increase in the reticulocyte number and RNA concentration in blood as well as by increased weight of spleen as the result of marked regeneration of extramedullar erythropoiesis, leukocytes as well as reticulocytes are assumed to be additionally registered by the automated counter CC in this period, probably due to a higher resistence of reticulocytes to the lysing agent Zapoglobine. (author)

323

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

Directory of Open Access Journals (Sweden)

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.

Anand M. Badigannavar and Suvendu Mondal

2010-03-01

324

Dense Electron-Positron Plasmas and Ultra-Intense Bursts of Gamma-Rays from Laser-Irradiated Solids  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In simulations of a 10PW laser striking a solid we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 10^26/m^3 is achieved, seven orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of gamma-rays of intensity 10^22W/cm^2, potentially the most intense gamma...

Ridgers, C. P.; Brady, C. S.; Duclous, R.; Kirk, J. G.; Bennett, K.; Arber, T. D.; Robinson, A. P. L.; Bell, A. R.

2012-01-01

325

Gamma rays control coding moths  

International Nuclear Information System (INIS)

Gamma rays are being tested as a means of controlling codling moths, Cydia pomonella (L.), under fruit storage conditions where fumigation will not work. Preliminary tests have shown that gamma radiation kills all exposed codling moth larvae, including larvae in the dormant stage. There is no carryover of radiation in the fruit and minimal effect on the fruit. Gamma irradiation of food is considered safe for human consumption at doses of 1 kilogray (10 kilorads) or less

326

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

International Nuclear Information System (INIS)

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

327

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

International Nuclear Information System (INIS)

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

328

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

International Nuclear Information System (INIS)

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

329

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

Scientific Electronic Library Online (English)

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

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

330

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

Directory of Open Access Journals (Sweden)

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.

Xie Chuan-Xiao

2004-01-01

331

Electron and positron contributions to the displacement per atom profile in bulk multi-walled carbon nanotube material irradiated with gamma rays  

International Nuclear Information System (INIS)

The electron and positron contributions to the effective atom displacement cross-section in multi-walled carbon nanotube bulk materials exposed to gamma rays were calculated. The physical properties and the displacement threshold energy value reported in literature for this material were taken into account. Then, using the mathematical simulation of photon and particle transport in matter, the electron and positron energy flux distributions within the irradiated object were also calculated. Finally, considering both results, the atom displacement damage profiles inside the analyzed bulk carbon nanotube material were determined. The individual contribution from each type of secondary particles generated by the photon interactions was specified. An increasing behavior of the displacement cross-sections for all the studied particles energy range was observed. The particles minimum kinetic energy values that make probabilistically possible the single and multiple atom displacement processes were determined. The positrons contribution importance to the total number of point defects generated during the interaction of gamma rays with the studied materials was confirmed

332

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

International Nuclear Information System (INIS)

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

333

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

International Nuclear Information System (INIS)

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

334

Indirect genotoxic effect of gamma rays in human peripheral lymphocytes  

International Nuclear Information System (INIS)

The aim of this study was to investigate the indirect genotoxic effect of various doses of gamma rays in human peripheral lymphocytes. For this aim, chromosome mediums were irradiated with various doses (2000, 4000, 8000, 16000 rad) of gamma rays. In this study, we were found that SCE (Sister Chromatid Exchange) was increased by gamma rays doses-dependently. In addition to these, percentages of abnormal cells with chromosomal abnormalities and CA (Chromosome Aberration)/Cell were increased by all doses of gamma rays compared to control. Besides, gamma rays decreased the MI dose-dependently. RI was not also reduced at all concentrations. (author)

335

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-01-15

336

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

International Nuclear Information System (INIS)

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. CV and G/?V measurements were recorded prior to and after irradiation at high (1 MHz) frequency. The effects of the radiation were determined from analysis of the CV and G/?V curves. A slightly decrease in the 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

337

Effect of grape procyanidin on the abnormal expressions of Bcl-2 and Bax protein in pancreas cells irradiation with gamma rays  

International Nuclear Information System (INIS)

Objective: To investigate the effect of grape procyanidin (CPC)on the cell apoptosis and expressions of Bcl-2 and Bax protein in pancreas cells of mice irradiated with gamma rays. Method: CPC was intragastrically administrated to the mice and then irradiated with 60Co-? rays 5 times per week for 4 weeks, dose was 2.5 Gy in total. All mice were executed on the second day after the last irradiation. Three indices including expression of Bcl-2 and Bax protein and ultrastructure of pancreas cells were examined. Result: The Bcl-2 expression rate was 51.1% in the CPC protection group, higher than that in the irradiated control group. Bax expression, however, was lower than that in the irradiated control group. All the differences mentioned above were statistically significant (P<0.01). Injury to cell ultrastructure was alleviated in the GPC protection group. Conclusion: The present study showed that GPC can inhibit radiation-induced cell apoptosis and abnormal expression of Bcl-2 and Bax protein in pancreas cells, and can prevent from chronic radiation injury. (authors)

338

Gamma-ray sources  

International Nuclear Information System (INIS)

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

339

Analysis on Bulk Radiation Damage of SiC Semiconductor Radiation Detector irradiated by Co-60 Gamma Ray  

International Nuclear Information System (INIS)

Semiconductor radiation detectors have been investigated for many applications within various environments. The harsh radiation environments such as a nuclear reactor, high energy physics experiments, or outer space can cause radiation damages to detectors. The radiation-induced damage can be classified into two categories of the bulk and surface effects. The most fundamental type of bulk radiation damage is the Frenkel defect, produced by the displacement of an atom of the semiconductor material from its normal lattice site. The vacancy left behind, together with the original atom now at an interstitial position, constitutes a trapping site for normal charged carriers. These are sometimes called point defects to distinguish them from more complex 'clusters' of a crystalline damage. Gamma rays create only point defects. When enough of these defects have been formed, a carrier lifetime is reduced. Therefore, a radiation damage which deteriorates the performance of a device is a serious and important problem for semiconductor radiation detectors

340

Frequency of reciprocal translocations as a function of gamma-ray dose in acute spermatogonial irradiation of the rabbit  

International Nuclear Information System (INIS)

Adult rabbit males were given acute gamma-ray exposures at dose levels of 0.5, 1.0, 3.0, or 5.0 Gy. The reciprocal translocations arisen at the premeiotic cytogenetic techniques at a 5 month postradiation. The findings indicated that increasing the dose up to 3.0 Gy resulted in a rise of translocation yields, while 5.0 Gy doses produced an abrupt fall. For the dose range studied, dose-response data were best described by a linear-quadratic equation. Based on the evidence of peak translocation yields obtained with 3.0 Gy exposures, rabbit spermatogonia were characterized as being more sensitive to radiation cell killing, as compared to mouse spermatogonia, where maximum translocation yields are reportedly observed at 6 to 8 Gy doses. As opposed to this, genetic radiosensitivity of spermatogonia proved lower in the rabbit than in the mouse. (A.B.)

 
 
 
 
341

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

International Nuclear Information System (INIS)

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

342

An approach to reuse of PCB-contaminated transformer oil using gamma radiolysis. Basic decomposition property of PCB and 1,2,4-trichlorobenzene under gamma ray irradiation  

International Nuclear Information System (INIS)

The radiolytic decompositions of low-concentration polychlorinated biphenyls (PCB) and 1,2,4-trichlorobenzene (TCBz) in a transformer oil have been studied using a 60Co gamma ray irradiation facility. Significant decompositions of PCB and TCBz were observed in the oil at tens of kGy absorbed dose without any additive. We derived the required dose for KC500 decomposition in transformer oil using a power function, which indicates that oil with lower PCB concentration needs less dose to treat PCB wastes. We also observed that the gamma radiolyses of PCB and TCBz did not affect each other; the decompositions of PCB and TCBz proceed independently. Both PCB concentration analysis and total chlorine mass concentration analysis indicated that most dechlorinated chlorine atoms react to generate other chlorine compounds in the oil. We found that the gamma radiolysis without additional compounds in the oil can be a useful way of reusing PCB-contaminated transformer oil. (author)

343

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

International Nuclear Information System (INIS)

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

344

Effect of ?-irradiation on the properties of poly(ester urethane) elastomer  

International Nuclear Information System (INIS)

The influence of irradiation with 60Co ?-rays on gelation, change in the mechanical characteristics, and the formation of supramolecular structure in a poly(ester urethane) elastomer synthesized from oligoether adipate and diisocyanate, as well as a diol with or without double carbon-carbon bonds, was studied. It was found that the presence of double carbon-carbon bonds in the structure of the elastomer ensures the predominance of crosslinking over degradation processes. It was shown that ?-irradiation at a dose of 380 kGy is accompanied by the formation of a microglobular structure of ?1 ?m size. The specifics of changes in the mechanical characteristics depending on the absorbed dose are discussed

345

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

International Nuclear Information System (INIS)

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

346

Conversion of Ce{sup 3+} to Ce{sup 4+} ions after gamma ray irradiation on CeO{sub 2}-PbO-B{sub 2}O{sub 3} glasses  

Energy Technology Data Exchange (ETDEWEB)

The structural and optical parameters of gamma ray irradiated cerium doped lead borate glasses have been analyzed using FTIR, UV-visible absorption, transmittance and density measurement techniques. It has been observed that due to gamma ray exposure, the optical band gap decreases, density increases and molar volume decreases correspondingly. FTIR spectroscopy confirms the conversion of [BO{sub 3}] to [BO{sub 4}] and also shows the presence of [CeO{sub 4}] groups of cerium in glass samples. The transmittance of the glass samples decreases due to formation of hole centers.

Pal Singh, Gurinder; Kaur, Parvinder; Kaur, Simranpreet; Kaur, Ravneet [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Singh, D.P., E-mail: dpsinghdr@yahoo.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

2013-01-01

347

Gamma-ray bursts  

International Nuclear Information System (INIS)

The discovery of visible light from gamma-ray bursts has revealed that these puzzling objects lie among the most distant quasars and galaxies in the universe, while radio observations have highlighted their ultrarelativistic nature GAMMA-RAY bursts are one of the top unsolved mysteries in astrophysics, alongside such burning issues as the nature of dark matter and the cosmological constant. We have known of the existence of gamma-ray bursts for over 25 years, but these short flashes of gamma rays have defied all our attempts to understand their causes and origin. New clues to the mystery were provided on 28 February 1997, when the BeppoSAX satellite located a gamma-ray burst more quickly and precisely than ever before. This allowed astronomers to image the burst, revealing a rapidly fading point of light near a faint nebula. Another gamma-ray burst was found in the same way a few months later, and this time the optical spectrum was recorded by the Keck telescope on Hawaii. This told us unambiguously that gamma-ray bursts lie at the very edges of the universe, making them the most energetic phenomenon we know of. Although these findings have solved part of the puzzle, we still do not know what causes gamma-ray bursts. Their formation appears to be related to the deaths of massive stars, and almost certainly requires matter to be flung into space at close to the speed of light. The bursts are so bright that they can be detected out to very great distances, and could eveout to very great distances, and could even hold the record for the most distant known objects. In principle, more sensitive detectors could see gamma-ray bursts from even further away. This could prove to be the only way of observing the early universe, when the first stars and galaxies were forming. (author)

348

Gamma-ray Astronomy  

CERN Document Server

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.

Hinton, Jim

2007-01-01

349

Gamma-Ray Bursts  

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

Rau, Arne

2012-01-01

350

DNA fragmentation in AG1522 human fibroblasts irradiated with gamma-rays and charged particles: theoretical analysis  

International Nuclear Information System (INIS)

A phenomenological model of DNA double strand breaks (DSB) induction has been implemented to characterise the differences among experimental DNA fragmentation spectra. Data concern spectra induced in AG1522 human fibroblasts by several doses of gamma-rays, low-energy protons of 0.88 MeV and iron ions of 115 MeV/u and of 1 GeV/u, and were obtained by gel electrophoresis in the size range from few Mbp down to few kbp. The computational method makes first a comparison between the experimental fragmentation spectra and those computed with a generalisation of the broken-stick model. The calculation considers the DNA DSB induced by radiation as randomly placed, but the manifestly non-random fragmentation of the control sample is taken into account and considered as the initial fragment distribution. Then, an analytical method is introduced, that allows an evaluation of the deviation from randomness of the radiation-induced fragmentation. The analysis of the experimental spectra shows that there is an increasing departure from randomness in the following order: gamma-rays, protons, 1 GeV/u iron ions and 115 MeV/u iron ions. This deviation is characterised by an enhanced induction of fragments in the experimental range of lower molecular weights, and therefore by a larger correlation between double strand breaks at distances corresponding to the sizes of these smaller fragments. This is most probably due to a larger intratrack component in the fragment production by high-LET nt in the fragment production by high-LET radiation. In fact, the results show that for the 0.88 MeV protons, that have an LET substantially lower than the 1 GeV/u and 115 MeV/u iron ions, and therefore a higher fluence at the same dose, the fragmentation is more random at the higher doses. The analysis clearly distinguishes the fragmentation spectra induced by different radiation qualities, and it could offer a basis for the study of the link between the DNA damage, correlated at various spatial scales, and biological end points

351

Sodium-22 accumulation and removal as a criterion of the cell membrane state after irradiation with gamma rays  

International Nuclear Information System (INIS)

The data are presented on the accumulation and removal of sodium-22 from tissues of intact and lethally irradiated mice. The radioisotope was accumulated primarily by tissues of irradiated animals, as compared to intact controls, in the course of the first 4 hours after irradiation, then it was intensively removed from tissues. It is assumed that this criterion (accumulation and removal of sodium) could be used to determine the state of cell membranes early after irradiation with lethal doses

352

Structural change of the IR-transmitting tellurite, gallate and aluminate glasses caused by the 60Co-gamma ray irradiation  

International Nuclear Information System (INIS)

The 57Fe-Moessbauer parameters of ?-ray irradiated xK2O(95-x)TeO25Fe2O3 (x=5,25), xMgO(95-x) TeO25Fe2O3 (x=5,25) and 95TeO25Fe2O3 glasses suggest a cleavage of Te(Fe)-O-Te bond and an increase of the symmetry of Te(Fe)O4 trigonal bipyramids. There is a linear relationship between the resultant Tg and the quadrupole splitting (?), obeying the 'Tg-? rule'. A cleavage of Ga(Fe)-O-Ga bond and an increased symmetry of Ga(Fe)O4 tetrahedra are found in the irradiated 50CaO40Ga2O310Fe2O3 glass. The X-ray diffraction and FT-IR absorption spectra indicate the precipitation of Ga2O3 and CaO phases, and a marked decrease of transmittance is observed in the FT-IR transmission spectra. On the contrary, gamma-ray irradiated xCaO(95-x)Al2O35Fe2O3 glasses (x=55?60) show little change in the structure nor the IR transparency. (author)

353

Gamma-ray Irradiation Impairs Dendritic Cell Migration to CCL19 by Down-regulation of CCR7 and Induction of Cell Apoptosis  

Directory of Open Access Journals (Sweden)

Full Text Available Dendritic cells (DCs are the most potent antigen-presenting cells and play a crucial role in the regulation of immune response and migration of DCs into secondary lymphoid tissues also play an important role in the initiation of innate and adaptive immunity. Radiation therapy is now a routine treatment for certain types of cancer and over 20 percent of cancer patients will require radiation therapy during the treatment of their disease. However, the influence of ionizing irradiation on the migratory ability of DCs is largely unknown. In this article, we report that ? ray irradiation can significantly inhibit LPS-triggered up regulation of CCR7 expression and PGE2 production by DC, thus impairing DC migration towards CCL19 in vitro and in vivo. Moreover, ? ray exposed DC also displayed an increased apoptosis rate and decreased cell viability. Furthermore, we demonstrate that exogenous PGE2 can partly reduce the gamma-ray induced migratory impairment and restored CCR7 expression of DC. Our work suggests that ? irradiation affects DC function at multiple steps during the immune response including DC migration, and that PGE2, via control of CCR7 expression, is an important regulator of DC migration.

Cong Liu, Jin Lin, Luqian Zhao, Yanyong Yang, Fu Gao, Bailong Li, Jianguo Cui, Jianming Cai

2011-01-01

354

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

International Nuclear Information System (INIS)

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

355

Gamma ray attenuation measurements  

International Nuclear Information System (INIS)

The good resolution of a Ge(Li) detector was used to measure gamma ray attenuation coefficients in narrow beam geometry. The effect of multiple scattering on the pulse height distribution of the transmitted gamma rays and on the measured attenuation coefficients was studied and shown to be small up to three mean free paths. Values of attenuation coefficients were determined in the case of lead for 0.662 MeV, 1.116 MeV, 1.17 MeV and 1.33 MeV gamma rays, and in the case of tantalum and molybdenum for 0.662 MeV and 1.116 MeV gamma rays. The experimental values are in fair agreement with the calculated ones. (Auth.)

356

Outcrop gamma ray logging  

International Nuclear Information System (INIS)

Reliable, reproducible gamma-ray logs of outcrops have been generated by two techniques with the objective of better visualizing interwell-scale lateral continuity (and discontinuity) of strata and to demonstrate reliability and potential pitfalls in subsurface wireline log correlations. One innovative technique was developed with uses a standard gamma-ray sonde run from a logging truck to log vertical cliff or quarry faces. The second technique employs a hand-held gamma-ray scintillometer to log more easily accessible outcrops. In this paper examples are presented from the Jackfork Group (Pennsylvanian), Arkansas of outcrop gamma-ray logging of both laterally continuous and discontinuous turbidites in structurally simple and complex settings. The authors have found that by using these examples, the following common wireline log correlation problems can be clearly explained to engineers and geoscientists, and understood, because the strata from which the logs were measured can be visualized and discussed at the outcrop

357

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  

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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)

Cardi, Bruno Andrade

1999-07-01

358

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

International Nuclear Information System (INIS)

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

359

New gamma rays from the 189W decay  

International Nuclear Information System (INIS)

Radioactivities of 189W are produced through an 192Os(n,?)189W reaction. The natOs targets are irradiated with 14 MeV neutrons. Gamma ray spectroscopy from the chemically separated tungsten sources using an HPGe detector has revealed the presence of twenty-two gamma rays which can be assigned to the decay of 189W. Eighteen of them are new gamma rays which have never been reported before

360

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

International Nuclear Information System (INIS)

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

 
 
 
 
361

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

International Nuclear Information System (INIS)

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

362

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

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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 {gamma}-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.

Nho, Y.C. E-mail: ycnho@kaeri.re.kr; Mook Lim, Youn; Moo Lee, Young

2004-10-01

363

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

International Nuclear Information System (INIS)

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

364

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

International Nuclear Information System (INIS)

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

365

Influence of pre-sowing irradiation of soya seeds with low doses of gamma rays on the yields of grain and on the content of crude protein in the grain  

International Nuclear Information System (INIS)

Pre-sowing irradiation of air-dry soya seeds of the Hodson variety, calibrated in size and humidity (12%), with gamma rays in the range of relatively low intensities of irradiation of 0.27 to 5 Gy/min and doses of 10 to 20 Gy increases both the yield of grain and the content of crude protein in the grain in relation to the absolute dry matter. The dependence of radiostimulation effect on the factors of the environment cannot be reason for neglecting it as a posssible reserve for increasing the yield of grain from soya and the content of crude protein in the grain. Possible results are exspected from production experiments with pre-sowing irradiation of seeds of Hodson variety using gamma rays in the range of the above intensities and doses

366

Thermo-mechanical characteristics of UV-irradiated polyurethane elastomers extended with ?, ?-alkane diols  

International Nuclear Information System (INIS)

A series of polyurethane elastomers were prepared by the reaction of poly ?-caprolactone and 4,4'-diphenylmethane diisocyanate. The prepolymer was extended using ?, ?-alkane diols as chain extenders having 2-10 methylene units in their structure. The synthesized samples were irradiated for 50, 100 and 200 h in an ultra violet (UV) exposure unit. Modifications in the chemical structure before and after irradiation were characterized using Fourier Transform Infrared spectroscopy. The thermal and mechanical properties were affected by the ultra violet irradiation time and the number of methylene units in the chain extenders. The experimental results indicated that the morphological structure changed during irradiation as a consequence of hard segment and soft segment degradation.

367

Gamma ray camera  

Science.gov (United States)

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

Perez-Mendez, V.

1997-01-21

368

Gamma ray camera  

Science.gov (United States)

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

Perez-Mendez, Victor (Berkeley, CA)

1997-01-01

369

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

International Nuclear Information System (INIS)

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

370

Moisture and gamma-ray irradiation effects on the mechanical properties of carbon fibre-reinforced plastics.  

Science.gov (United States)

The effects of gamma-irradiation and moisture absorption on the mechanical properties of carbon fibres-epoxy resin composites were studied. The properties dominated by the matrix and fibre-matrix interface (interlaminar and in-plane shear strength) were measured at room temperature using standard tests. These tests were carried out before and after exposures to gamma irradiation and before and after immersion in water at 80 degrees C during 21 days. The dosage of gamma irradiation was up to 11.7 MGy. The micrographs of surfaces fractured in performed tests were observed on a scanning electron microscope. They were analyzed with consulting the stated effects on mechanical properties and the measured values of the glass transition temperature of tested coupons before and after irradiation and immersion in water. The obtained results show that moisture and irradiation, if they act one after the other, have a significant influence on the degradation of matrix-dominated mechanical properties of the tested carbon-epoxy composite. PMID:19094048

Sekuli?, D; Bozi?, D; Babi?, B; Stasi?, J; Stevanovi?, M

2008-12-01

371

Continuous irradiation of mammalian cells with /sup 137/Cs gamma rays and the low energy emission from /sup 125/I  

International Nuclear Information System (INIS)

Cultured mammalian cells in plateau phase represent an in vitro system which has several of the characteristics of human tumors. The mouse embryo C3H/10T1/2 CL8 line is useful in this connection; the cells exhibit contact inhibition, and have a cycling fraction of 14-16% after 3 days at saturation density. Cells were irradiated with /sup 137/Cs and /sup 125/I at dose rates of 10-76 cGy/hr from 5-96 hours. The dose-response curve for cells irradiated in acute exposures has a broad initial shoulder. As the dose-rate is reduced, the slope of the survival curve becomes progressively shallower, and the extrapolation number tends to unity. No difference in survival was seen for immediate or 24 hours delayed plating for 16-96 hours, indicating that essentially complete repair of potentially lethal damage had taken place during the irradiation. A survival increase of 1.4 fold was seen with 24 hours delayed plating for 5 hours irradiation at 72 cGy/hr. Currently, irradiation studies are being undertaken on human cell lines of both normal and malignant origin. AG1522 human fibroblasts are being studied as an in vitro cell culture system representative of normal diploid cells. Cells of malignant origin being studied include human melanoma cells

372

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

Science.gov (United States)

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

Ito, Hitoshi; Islam, Md. Shamsul

1994-06-01

373

Irradiation treatments to improve the shelf life of fresh black truffles (truffles preservation by gamma-rays).  

Science.gov (United States)

The aim of this study was to individuate a method to improve the shelf life of fresh truffles, hypogeous fungi highly prized but very perishable as well. Microbial ecology of fresh products was investigated and the effect of irradiation at different doses on microbial and sensorial parameters was assayed. Data showed that fresh truffles are strongly contaminated from different groups of microorganisms. Irradiation was able to influence their growth, determining an impressive reduction. Treatments at 5 and 10 kGy doses produced the highest microbial decontamination but negatively influenced sensorial parameters. Irradiation at a 1.5 kGy dose was the best solution to improve the shelf life of truffles. PMID:19490339

Reale, Anna; Sorrentino, Elena; Iacumin, Lucilla; Tremonte, Patrizio; Manzano, Marisa; Maiuro, Lucia; Comi, Giuseppe; Coppola, Raffaele; Succi, Mariantonietta

2009-01-01

374

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

International Nuclear Information System (INIS)

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

375

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

International Nuclear Information System (INIS)

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

376

Sensitivity of mutant genotypes of chrysanthemum to gamma rays  

International Nuclear Information System (INIS)

Sensitivity of different Chrysanthemum cultivars to gamma rays have been determined on the basis of different cytomorphological parameters. Literature of testing sensitivity of different mutant genotypes of Chrysanthemum, developed through gamma irradiation, is scanty. The present paper reports the comparative radiosensitivity of one Chrysanthemum cultivar and one of its gamma ray induced mutant. (author). 10 refs., 1 fig., 2 tabs

377

Gamma Ray Bursts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 interp...

Me?sza?ros, Peter

2012-01-01

378

Gamma Ray Bursts  

Science.gov (United States)

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.

Gehrels, Neil; Meszaros, Peter

2012-01-01

379

Gamma-ray Astronomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 topi...

Hinton, Jim

2007-01-01

380

Primary explants of human uroepithelium show an unusual response to low-dose irradiation with cobalt-60 gamma rays  

International Nuclear Information System (INIS)

Recent results using very low doses of radiation have suggested that there is a hypersensitive region where cultures show an enhanced level of cell killing leading to a non-monotonic survival curve. This effect has been observed at doses below 2 Gy in mammalian systems and at much higher doses in insect cells. In this paper we report observation of the effect in primary human uroepithelial cell cultures. The effect was measured using a postirradiation proliferation assay where irradiated explants of standard size were allowed to proliferate for 14 days after exposure to 60Co? irradiation. By 14 days the majority of cultures derived from explants irradiated with 2-5 Gy showed little evidence of growth inhibition and cell numbers approached or even exceeded those obtained in the controls. There was, however, a significant reduction in cell number and growth rate in all cultures exposed to doses lower than 1 Gy. Oncoprotein and EGFR expression were also measured in these cultures and were significantly increased. Morphological evidence of apoptosis was present in all irradiated cultures at 4 h after exposure, but this persisted for longer periods in cultures exposed to low doses. 18 refs., 2 figs., 4 tabs

 
 
 
 
381

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

International Nuclear Information System (INIS)

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

382

Fibrin degradation activity of rat bone marrow and its variation following whole body gamma-ray irradiation  

International Nuclear Information System (INIS)

1) A high fibrin degradation activity was extracted with 2 M KSCN from rat bone marrow. The activity was clearly demonstrated on plasminogen-free fibrin plates, whereas it was not shown on plasminogen-rich fibrin plates. The activity thus apparently differs from plasminogen activator. The activity was strongly inhibited with STI as well as DFP, while it was barely inhibited with TLCK, t-AMCHA and aprotinin, suggesting that it is identical or similar to Okamoto's factor. 2) Whole body single irradiation was performed in rats using 60Co-?-rays at dose of 700 to 800 R. The fibrin degradation activity of the bone marrow extract was observed to decrease to as low as 50% of its normal level on the 3rd day after irradiation, and then tended to recover. The damage to the bone marrow due to the irradiation effects was the greatest on the 3rd day after irradiation as indicated by the maximum decrease in the number of bone marrow cells. The activity is therefore suggested to be bone marrow cell origin. (author)

383

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

International Nuclear Information System (INIS)

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

384

Methylperoxyl radicals as intermediates in the damage to DNA irradiated in aqueous dimethyl sulfoxide with gamma rays  

Energy Technology Data Exchange (ETDEWEB)

Using agarose gel electrophoresis, we have measured the yields of DNA single-strand breaks (SSBs) for plasmid DNA {gamma}-irradiated in aerobic aqueous solution. Incubation after irradiation with the base damage repair endonucleases formamidopyrimidine-DNA N-glycosylase (FPG) or endonuclease III (endo III) results in an increase in the yield of SSBs. In the absence of dimethyl sulfoxide (DMSO) during irradiation, this increase is consistent with the yields of known substrates for FPG and endo III as determined by gas chromatography/mass spectrometry. After irradiation in the presence of 1 mol dm{sup {minus}3} DMSO, the increase in the yield of SSBs after enzyme incubation was further enhanced by a factor of about 5 to 7. The magnitude of this effect, the inability of acrylamide or oxygen to suppress it, and its attenuation by N,N,N{prime}, N{prime}-tetramethylphenylenediamine (TMPD) or glycerol all suggest that the methylperoxyl radical (derived from DMSO) is involved as an intermediate. Reactions of the methylperoxyl radical (or some other species derived from it) do not result in strand break damage, but are responsible for DNA base damages which which are recognized by FPG and endo III. 41 refs., 5 figs.

Milligan, J.R.; Ng, J.Y.Y.; Wu, C.C.L. [Univ. of California at San Diego, La Jolla, CA (United States)] [and others

1996-10-01

385

Measurement of dose profile in aluminum, irradiated with thermal neutron capture gamma rays, by using the thermoluminescent dosimeter CaSO4:Dy  

International Nuclear Information System (INIS)

Gamma radiation with energies greater than 1.25 MeV are usually produced in reactor environments, particle accelerators and in cosmic radiation fields. For these energies, the response of a dosimeter heavily vary with the absorber material thickness, up to attain a maximum value named as charged particle equilibrium thickness. The main goal of this paper was the experimental determination of the absorbed dose profile in an aluminum sample for several energies of gamma ray beam, in order to obtain a relationship between the average energy of the gamma radiation field and the charged particle equilibrium thickness. The dosimeters were irradiated with gamma radiation produced by thermal neutron capture in 23 target materials in the experimental arrangement mounted at the tangential beam hole of the IPEN-CNEN/SP reactor. For the determination of the charged particle equilibrium thickness, it was fitted to the experimental data a semi-empirical function which allowed to obtain the thickness of CTPE (Charged Particle Transient Equilibrium) for each gamma radiation spectrum used in this work, with average energy varying in the interval from 3.26 to 7.85 MeV. The experimental results of the present paper allowed to obtain a relationship between average energy of the radiation field and the CTPE thickness, which presents an excellent agreement with the corrected range for electrons produced in that energy. (author)

386

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

International Nuclear Information System (INIS)

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)

387

Effect of spermidine on the survival of saccharomyces cerevisiae cells irradiated with different doses of gamma rays  

International Nuclear Information System (INIS)

Saccharomyces cerevisiae cells were used to test the radioprotective effect of added spermidine [H3N(CH2)3NH2(CH2)4NH3]3+ as one of the natural polyamines that are essential for cell life. Spermidine plays an important role in suppressing radiation damages at certain concentration (10-5M/L), either via scavenging free radicals or via reducing the frequency of radiation - induced mutations. Spermidine increased noticeably the D10 value at concentration of 10-5 M/L compared with the other two used concentrations of 10-6 and 10-4 M/L. Applying spermidine before irradiation was more effective than applying it after irradiation. (author)

388

Inverse gamma ray dose rate effect in californium-252 RBE experiment with human T-1 cells irradiated in vitro  

Energy Technology Data Exchange (ETDEWEB)

Metabolically deoxygenated suspensions of human T-1 cells were used to determine the RBE in hypoxia of low dose rate (LDR) Cf-252 radiation compared to LDR gamma radiation. Based upon the initial portion of the survival curves the RBE was 5.0 +- 1.0 for all components of the Cf-252 radiation and 7.1 +- 1.7 for the neutrons alone. An inverse dose rate effect was observed for LDR gamma radiation in which greater cell sensitivity was observed at lower dose rates and longer irradiation periods. It was demonstrated that there was little or no sublethal damage repair or cell progression during LDR at 21/sup 0/C. and the observed decrease in cell survival probability with increasing irradiation time at a given dose was attributable to reoxygenation of the cell suspensions during the course of LDR exposures.

Todd, P.; Feola, J.M.

1986-01-01

389

Inverse gamma ray dose rate effect in californium-252 RBE experiment with human T-1 cells irradiated in vitro  

International Nuclear Information System (INIS)

Metabolically deoxygenated suspensions of human T-1 cells were used to determine the RBE in hypoxia of low dose rate (LDR) Cf-252 radiation compared to LDR gamma radiation. Based upon the initial portion of the survival curves the RBE was 5.0 1.0 for all components of the Cf-252 radiation and 7.1 1.7 for the neutrons alone. An inverse dose rate effect was observed for LDR gamma radiation in which greater cell sensitivity was observed at lower dose rates and longer irradiation periods. It was demonstrated that there was little or no sublethal damage repair or cell progression during LDR at 21 deg C, and the observed decrease in cell survival probability with increasing irradiation time at a given dose was attributable to reoxygenation of the cell suspensions during the course of LDR exposures. (Auth.)

390

Characterization by EPR of radicals in HDPE, PA6 and HDPE/PA6 blend irradiated with gamma rays  

International Nuclear Information System (INIS)

Using electron paramagnetic resonance (EPR), we studied the tree radical formation in high-density Polyethylene (HDPE), polyamide (PA6) and HDPE/PA6 (80/20)blend, irradiated with integral doses (D), 0 < D < 1000 KGy, with a dose rate of irradiation in air of 6.6 KGy/h. Typical spectra indicative of the formation of allyl, alkyl and poly enyl radicals were obtained. A decay in the total number of spins per gram (C/g), when the samples are aged by a period of time of 30 days, was found, which is typical of a recombination of radicals with their environment. Additionally, a different order fit for the C/g as a function of D was obtained, which is indicative of the complex behavior of the kinetics of the decomposition. (Author)

391

Molecular characterisation of murine acute myeloid leukaemia induced by 56Fe ion and 137Cs gamma ray irradiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Exposure to sparsely ionising gamma- or X-ray irradiation is known to increase the risk of leukaemia in humans. However, heavy ion radiotherapy and extended space exploration will expose humans to densely ionising high linear energy transfer (LET) radiation for which there is currently no understanding of leukaemia risk. Murine models have implicated chromosomal deletion that includes the hematopoietic transcription factor gene, PU.1 (Sfpi1), and point mutation of the second PU.1 allele as th...

Steffen, Leta S.; Bacher, Jeffery W.; Peng, Yuanlin; Le, Phuong N.; Ding, Liang-hao; Genik, Paula C.; Ray, F. Andrew; Bedford, Joel S.; Fallgren, Christina M.; Bailey, Susan M.; Ullrich, Robert L.; Weil, Michael M.; Story, Michael D.

2012-01-01

392

Resveratrol effects on life span and fertility of caenorhabditis elegans subject to 60Co gamma ray irradiation  

International Nuclear Information System (INIS)

Caennorhabditis elegans was used as experimental model to investigate radiation effect of resveratrol on caenorhabditis elegans irradiated by 60Co ? ray. Treatment with resveratrol can increase average life span and spawning rate, improve the survival rate of eggs, and protect their mitochondrion function of caenorhabditis elegans exposure to 60Co ? ray. The results indicate that resveratrol has radiation protection effects, which might be related to its action on ROS decrease and mitochondrial defend. (authors)

393

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

International Nuclear Information System (INIS)

The present work was carried out in the laboratory of the Entomology Section of the Nuclear Energy for Agriculture Center (CENA) in Piracicaba, Sao Paulo state, Brazil, to determine the effects different gamma radiation doses on the reproductive potential of males and the flight behavior of Ceratitis capitata (Wied.). For all the treatments with gamma radiation a Cobalt-60 source type Gamma beam-650 was used, with activity of approximately 13,410 x 10B Bq. (4,967 Ci.), and the dose rate of 2.000 Gy per hour. The doses used were 80 Gy, 100 Gy and 120 Gy. The three doses employed affected more the longevity of males than the females and the number of spermatozoid found lower in the irradiated insects compared with the control, with no significant differences between doses. The insects irradiated with 80 Gy showed activity similar to the control population until four days after emergence: afterwards they were more active than the unirradiated. The gamma irradiation diminished the take-off ability of the insects. (author). 59 refs., 9 figs., 9 tabs

394

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

International Nuclear Information System (INIS)

The species of microorganisms which can grow on commercial viennas on the storage at 10 deg C were Lactobacillus, Streptococcus and yeasts. When the viennas specially made which did not contain preservatives in it were used for this investigation, growth of microorganisms such as Lactobacillus, Streptococcus, Micrococcus, Bacillus and yeasts were predominant on the storage at 10 deg C, and Pseudomonas and molds some time propagated. When smoked-viennas specially made for the National Project were used for preservation, growth of microorganisms consisted mainly of the species of Lactobacillus, Micrococcus, Acinetobacter, Flavobacterium, Streptococcus, Serratia, Corynebacterium and yeasts. Irradiation of viennas at 300 and 500 krad reduced the aforementioned flora to the Lactobacillus, Streptococcus, Acinetobacter and yeasts. The number of microorganisms on the viennas packed with nitrogen gas was not increased for 3 to 7 days by means of 300 krad irradiation, and extended the storage-life 2 to 3 times. When irradiated with a dose of 500 krad, the number of microorganisms was not increased for 9 to 14 days on the storage at 10 deg C. (author)

395

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

International Nuclear Information System (INIS)

The tebo worms or butterworms (Chilecomadia moorei) are widely used in Chile in fishing, and so are in the international markets although there are some countries, that use these species, to a less extent for preparing food reptiles. Some foreign countries requirements demand, from the exporters, to carry out quarantine treatments related to the sterilization by ionizing energy, however customers need to make sure about their products safety and that is why it is compulsory to establish limits in connection with worms' irradiation resistance. The irradiation effect on a worms sample using doses of 0.3; 0.45; 0.6 and 0.9 kGy was studied macroscopically, after 1 hour, and then 30, 60 and 90 days after the treatment. One of the equipment utilized had a Cobalt 60 source, where as the other one had Cesium 137 irradiators, with a dose rate of 42.7 Gy minute (min)-1 and 37.1 Gy min-1, respectively. The results concluded that tebo worms can resist more than 3 times the doses suggested by the meta countries without reducing the population drastically, nevertheless it is required to increase the number of worms to be analyzed in order to validate the findings. (author)

396

Assessment of the radioprotective effects of amifostine and melatonin on human lymphocytes irradiated with gamma-rays in vitro  

International Nuclear Information System (INIS)

Radioprotective effects of amifostine and melatonin on human peripheral blood irradiated with g-rays were investigated using the micronucleus (MN) assay and the analysis of sister chromatid exchanges (SCE). Duplicate blood samples were pre-treated with amifostine (7.7 mM), melatonin (2 mM) and their combination for 30 minutes. Negative controls were also included. After treatment with radioprotectors, one blood sample from each experimental group was exposed to g-rays from a 60Co source. The radiation dose absorbed was 2 Gy. Pre-treated irradiated blood samples showed a decrease in the total number of MN and in the number of cells with more than one MN. Moreover, they also showed significantly lower mean SCE values. Our results indicate that amifostine, melatonin and their combination in vitro have radioprotective effects on g-irradiated human peripheral blood lymphocytes, with no significant genotoxicity. Therefore, it may be reasonable to use them in combination, adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. Before employment, this combination should be extensively tested in vitro and in vivo, using the same and other biomarkers for different radiation dose and concentration ranges of both radioprotectors.(author)