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1

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

CERN Document Server

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

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

2005-01-01

2

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

Energy Technology Data Exchange (ETDEWEB)

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

Banerjee, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Sinha, N K [Innovative Design Engineering and Synthesis Section, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Gayathri, N [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Ponraju, D [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Dash, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Tyagi, A K [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Raj, Baldev [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India)

2007-02-07

3

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

4

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

5

Gamma-ray irradiation tests of High-Tc SQUID  

Energy Technology Data Exchange (ETDEWEB)

Gamma-ray irradiation tests of High-Tc SQUIDs were carried out to examine their workability in nuclear reactor environments. The SQUIDs were made of a HoBa{sub 2}Cu{sub 3}O{sub 7-x} superconductive thin film on SrTiO{sub 3} substrates. Some were encapsulated in separate cases of glass-fiber-rein-forced epoxy resin. Gamma-ray irradiation was performed with a Co-60 gamma-ray source. Irradiation dose rates were (8.1 to 12.2) x 10{sup 3} Gy/h (i.e., (1.0 to 1.5) x 10{sup 6} R/h), and the maximum absorption dose was about 10.4 MGy. During and after irradiation, noises of SQUIDs were measured with a power spectrum analyzer. Changes in modulation voltage were also investigated. No gamma-ray induced noise was observed during irradiation. The noise level and modulation voltage did not change until a total irradiation dose of about 3 MGy, and after that it decreased slightly. We concluded that the tested high-Tc SQUIDs are very resistant to gamma-ray irradiation, and thus the application of high-Tc SQUIDs in inspection of reactor components seems promising. (author)

Ara, K. [Tokyo Denki Univ., Applied Superconductivity Research Laboratory, Inzai, Chiba (Japan); Nagaishi, T.; Itozaki, H. [Sumitomo Electric Hightechs Co., Ltd., Development Division, Itami, Hyogo (Japan); Morita, Y. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2002-04-01

6

Gamma ray irradiation to semi-purified diet  

International Nuclear Information System (INIS)

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

7

Influence of gamma ray irradiation on metakaolin based sodium geopolymer  

Science.gov (United States)

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

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

2013-11-01

8

Influence of gamma ray irradiation on metakaolin based sodium geopolymer  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-11-15

9

Influence of gamma ray irradiation on metakaolin based sodium geopolymer  

International Nuclear Information System (INIS)

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

10

Gamma ray-irradiation in fresh allo-joint transplantation  

International Nuclear Information System (INIS)

In the first of a series of experiments in rat designed to assess the efficacy of gamma ray irradiation in fresh allo-joint transplantation, it was found that the optimal gamma ray dosage was 4 Gy. At this dosage level, the irradiation rays suppressed the viability of marrow cells which had the highest antigenicity, with no injury to the bone or articular cartilage. In a second experiment, a fresh homologous knee joint was irradiated at 4 Gy and then transplanted while administering the donor's splenic cell suspension (for specific immunosuppression) and the immunosuppressive agent cyclosporine (5 mg/kg) to the recipient rat. All the rats that received a pre-irradiated knee joint graft survived until sacrificed for evaluation without showing any sign of host rejection. In these rats, bone fusion had occurred between the host bone and the graft by the 8th postoperative week. Degeneration of the articular cartilage was similar between the rats that had received a pre-irradiated graft and those that had not. These findings indicated that 4 Gy gamma ray irradiation to a graft before transplantation provided an effective means of immunosuppression. (author)

11

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)

12

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)

13

Gamma-ray irradiation of ohmic MEMS switches  

Science.gov (United States)

Radio Frequency (RF) Microelectromechanical System (MEMS) switches are becoming important building blocks for a variety of military and commercial applications including switch matrices, phase shifters, electronically scanned antennas, switched filters, Automatic Test Equipment, instrumentation, cell phones and smart antennas. Low power consumption, large ratio of off-impedance to on-impedance, extreme linearity, low mass, small volume and the ability to be integrated with other electronics makes MEMS switches an attractive alternative to other mechanical and solid-state switches for a variety of space applications. Radant MEMS, Inc. has developed an electrostatically actuated broadband ohmic microswitch that has applications from DC through the microwave region. Despite the extensive earth based testing, little is known about the performance and reliability of these devices in space environments. To help fill this void, we have irradiated our commercial-off-the-shelf SPST, DC to 40 GHz MEMS switches with gamma-rays as an initial step to assessing static impact on RF performance. Results of Co-60 gamma-ray irradiation of the MEMS switches at photon energies ? 1.0 MeV to a total dose of ~ 118 krad(Si) did not show a statistically significant post-irradiation change in measured broadband, RF insertion loss, insertion phase, return loss and isolation.

Maciel, John J.; Lampen, James L.; Taylor, Edward W.

2012-10-01

14

Experimental simulations of planetary gamma-ray spectroscopy using thick targets irradiated by protons  

Energy Technology Data Exchange (ETDEWEB)

To simulate planetary gamma-ray spectroscopy, gamma rays were measured during a series of five irradiations of up to 30-ton thick targets with protons beams of 1.5 and 2.5 GeV. The targets were steel (iron), basalt with structural steel, basalt with added S and Cl, and basalt with added H, S, and Cl. The pulsed proton beam was carefully monitored and counted. Spectra were collected with both proton beam on and beam off and with a lead shield both between the target and the germanium detector and with the lead shield removed. This set of four spectra was used to determine the fluxes of prompt gamma rays emitted from the target. Over 200 discrete gamma-ray lines per irradiation were observed and identified. Counting results for the more intense gamma rays were compiled, and gamma-ray fluxes determined for about 25 gamma rays of interest to planetary gamma-ray spectroscopy. The ratios of thermal and fast neutron induced gamma-ray fluxes between irradiations were similar. Thus the relative gamma-ray fluxes can be used in testing model calculations and interpreting planetary gamma-ray spectra.

Brueckner, J., E-mail: j.brueckner@mpic.de [Biogeochemistry Dept., Max-Planck-Institut f. Chemie, Postfach 3060, D-55020 Mainz (Germany); Reedy, R.C. [Planetary Science Inst., 152 Monte Rey Dr., Los Alamos, NM (United States); Englert, P.A.J. [Hawai' i Institute of Geophysics and Planetology (HIGP), University of Hawaii at Manoa, 1680 East-West Road, POST 509A, Honolulu, HI (United States); Drake, D.M. [TechSource, 1418 Luisa St., Santa Fe, NM (United States)

2011-11-15

15

Experimental simulations of planetary gamma-ray spectroscopy using thick targets irradiated by protons  

International Nuclear Information System (INIS)

To simulate planetary gamma-ray spectroscopy, gamma rays were measured during a series of five irradiations of up to 30-ton thick targets with protons beams of 1.5 and 2.5 GeV. The targets were steel (iron), basalt with structural steel, basalt with added S and Cl, and basalt with added H, S, and Cl. The pulsed proton beam was carefully monitored and counted. Spectra were collected with both proton beam on and beam off and with a lead shield both between the target and the germanium detector and with the lead shield removed. This set of four spectra was used to determine the fluxes of prompt gamma rays emitted from the target. Over 200 discrete gamma-ray lines per irradiation were observed and identified. Counting results for the more intense gamma rays were compiled, and gamma-ray fluxes determined for about 25 gamma rays of interest to planetary gamma-ray spectroscopy. The ratios of thermal and fast neutron induced gamma-ray fluxes between irradiations were similar. Thus the relative gamma-ray fluxes can be used in testing model calculations and interpreting planetary gamma-ray spectra.

16

Electrons versus gamma rays. Alternative sources for irradiation processes  

International Nuclear Information System (INIS)

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

17

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)

18

Elimination of gamma rays from a thermal neutron field for medical and biological irradiation purposes  

International Nuclear Information System (INIS)

When a research reactor is used as a neutron source, a considerable amount of contamination with gamma rays is unavoidable. In biological and medical uses of neutrons, the gamma rays from the reactor core become background against the thermal neutrons. The paper proposes the use of a bismuth scatterer as a gamma-ray eliminator by which a neutron field with very few gamma rays can be obtained. A lithium-fluoride tile, manufactured by the sintering method, was also found to be a good neutron collimator as it produces few gamma rays while absorbing neutrons. The boron accumulation effect in tissue was estimated for a tissue-equivalent liquid model. The importance of minimizing gamma-ray contamination in the thermal neutron field is emphasized for selective irradiation of the boron-containing tissue. The neutron field was applied to several experiments, such as biological experiments for the treatment of cancers. (author)

19

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

20

Induced parthenocarpy with pollen irradiated with gamma rays  

International Nuclear Information System (INIS)

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

 
 
 
 
21

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

International Nuclear Information System (INIS)

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)

22

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-06-15

23

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

24

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)

25

Semiconductor quantum dot scintillation under gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

We recently demonstrated the ability of semiconductor quantum dots to convert alpha radiation into visible photons. In this letter, we report on the scintillation of quantum dots under gamma-ray irradiation, and compare the energy resolution of the 59 keV line of Americium 241 obtained with our quantum dot-glass nanocomposite material to that of a standard sodium iodide scintillator. A factor 2 improvement is demonstrated experimentally and interpreted theoretically using a combination of energy-loss and photon transport models. These results demonstrate the potential of quantum dots for room-temperature gamma-ray detection, which has applications in medical imaging, environmental monitoring, as well as security and defense. Present technology in gamma radiation detection suffers from flexibility and scalability issues. For example, bulk Germanium provides fine energy resolution (0.2% energy resolution at 1.33 MeV) but requires operation at liquid nitrogen temperature. On the other hand, Cadmium-Zinc-Telluride is a good room temperature detector ( 1% at 662 keV) but the size of the crystals that can be grown is limited to a few centimeters in each direction. Finally, the most commonly used scintillator, Sodium Iodide (NaI), can be grown as large crystals but suffers from a lack of energy resolution (7% energy resolution at 662 keV). Recent advancements in nanotechnology6-10 have provided the possibility of controlling materials synthesis at the molecular level. Both morphology and chemical composition can now be manipulated, leading to radically new material properties due to a combination of quantum confinement and surface to volume ratio effects. One of the main consequences of reducing the size of semiconductors down to nanometer dimensions is to increase the energy band gap, leading to visible luminescence, which suggests that these materials could be used as scintillators. The visible band gap of quantum dots would also ensure both efficient photon counting (better coupling with photomultipliers optimized for the visible region), and high photon output (smaller individual photon energy results in more photons produced) at room temperature, which is essential for effective Poisson counting (the energy resolution {Delta}E/E is inversely proportional to the square root of the number of photons collected).

Letant, S E; Wang, T

2006-08-23

26

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-03-15

27

Studies of soy sauce sterilization and its special flavour improvement by gamma-ray irradiation  

International Nuclear Information System (INIS)

Experimental studies for sterilizing 12 kinds of soy sauce with gamma-ray irradiation showed that both sterilization and improvements in flavour and quality of soy sauce were obtained simultaneously. (author)

28

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

International Nuclear Information System (INIS)

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

29

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 plant’s 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

30

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

31

Gamma ray irradiated AgFeO2 nanoparticles with enhanced gas sensor properties  

Science.gov (United States)

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

Wang, Xiuhua; Shi, Zhijie; Yao, Shangwu; Liao, Fan; Ding, Juanjuan; Shao, Mingwang

2014-11-01

32

Prompt gamma-ray emission from biological tissues during proton irradiation: a preliminary study  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we present the results of a preliminary study of secondary 'prompt' gamma-ray emission produced by proton-nuclear interactions within tissue during proton radiotherapy. Monte Carlo simulations were performed for mono-energetic proton beams, ranging from 2.5 MeV to 250 MeV, irradiating elemental and tissue targets. Calculations of the emission spectra from different biological tissues and their elemental components were made. Also, prompt gamma rays emitted during delivery of a clinical proton spread-out Bragg peak (SOBP) in a homogeneous water phantom and a water phantom containing heterogeneous tissue inserts were calculated to study the correlation between prompt gamma-ray production and proton dose delivery. The results show that the prompt gamma-ray spectra differ significantly for each type of tissue studied. The relative intensity of the characteristic gamma rays emitted from a given tissue was shown to be proportional to the concentration of each element in that tissue. A strong correlation was found between the delivered SOBP dose distribution and the characteristic prompt gamma-ray production. Based on these results, we discuss the potential use of prompt gamma-ray emission as a method to verify the accuracy and efficacy of doses delivered with proton radiotherapy.

Polf, J C; Peterson, S; Ciangaru, G; Gillin, M; Beddar, S [Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States)], E-mail: jcpolf@mdanderson.org

2009-02-07

33

Prompt gamma-ray emission from biological tissues during proton irradiation: a preliminary study  

Science.gov (United States)

In this paper, we present the results of a preliminary study of secondary 'prompt' gamma-ray emission produced by proton-nuclear interactions within tissue during proton radiotherapy. Monte Carlo simulations were performed for mono-energetic proton beams, ranging from 2.5 MeV to 250 MeV, irradiating elemental and tissue targets. Calculations of the emission spectra from different biological tissues and their elemental components were made. Also, prompt gamma rays emitted during delivery of a clinical proton spread-out Bragg peak (SOBP) in a homogeneous water phantom and a water phantom containing heterogeneous tissue inserts were calculated to study the correlation between prompt gamma-ray production and proton dose delivery. The results show that the prompt gamma-ray spectra differ significantly for each type of tissue studied. The relative intensity of the characteristic gamma rays emitted from a given tissue was shown to be proportional to the concentration of each element in that tissue. A strong correlation was found between the delivered SOBP dose distribution and the characteristic prompt gamma-ray production. Based on these results, we discuss the potential use of prompt gamma-ray emission as a method to verify the accuracy and efficacy of doses delivered with proton radiotherapy.

Polf, J. C.; Peterson, S.; Ciangaru, G.; Gillin, M.; Beddar, S.

2009-02-01

34

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-08-01

35

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

International Nuclear Information System (INIS)

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

36

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.)

37

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.)

38

Electrical characteristics of {sup 60}Co {gamma}-ray irradiated MIS Schottky diodes  

Energy Technology Data Exchange (ETDEWEB)

In order to interpret the effect of {sup 60}Co {gamma}-ray irradiation dose on the electrical characteristics of MIS Schottky diodes, they were stressed with a zero bias at 1 MHz in dark and room temperature during {gamma}-ray irradiation and the total dose range was 0-450 kGy. The effect of {gamma}-ray exposure on the electrical characteristics of MIS Schottky diodes has been investigated using C-V and G/{omega}-V measurements at room temperature. Experimental results show that {gamma}-ray irradiation induces a decrease in the barrier height {phi} {sub B} and series resistance R {sub s}, decreasing with increasing dose rate. Also, the acceptor concentration N {sub A} increases with increasing radiation dose. The C-V characteristics prove that there is a reaction for extra recombination centers in case of MIS Schottky diodes exposed to {gamma}-ray radiation. Furthermore, the density of interface states N {sub ss} by Hill-Coleman method increases with increasing radiation dose. Experimental results indicate that the interface-trap formation at high irradiation dose is reduced due to positive charge build-up in the Si/SiO{sub 2} interface (due to the trapping of holes) that reduces the flow rate of subsequent holes and protons from the bulk of the insulator to the Si/SiO{sub 2} interface.

Tataroglu, A. [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)]. E-mail: ademt@gazi.edu.tr; Altindal, S. [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)

2006-11-15

39

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)

40

Swift heavy ion and gamma-ray irradiation of various double metal phosphates  

International Nuclear Information System (INIS)

The first-row transition metal salts of zirconium-, titanium-, and hafnium phosphates, respectively were irradiated at various doses with swift heavy ions of 240 MeV 84Kr and 720 MeV 203Bi and with gamma-rays of 60Co at dose of 3x106 Gy. Comparison of powder diffraction patterns of non-irradiated and irradiated samples reveals that the irradiation with gamma-rays has no effect on the materials. Irradiation with swift heavy ions of 84Kr and 203Bi at higher dose caused some degradation of the structure of titanium and hafnium double metal phosphates. The electrical conductivity value of the irradiated samples remained inside the order of magnitude characteristic for untreated materials

 
 
 
 
41

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)

42

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

43

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

44

Successive gamma-ray irradiation and corresponding post-irradiation annealing of pMOS dosimeters  

Directory of Open Access Journals (Sweden)

Full Text Available The paper investigates a possibility of pMOS dosimeter re-use for the measurement of gamma-ray irradiation. The dosimeters were irradiated to the dose of 35 Gy, annealed at room and elevated temperatures, after which they were irradiated again to the same dose value. Changes in the threshold voltage shift during those processes were followed, and it was shown that their re-use depends on a gate polarization during irradiation. For the gate polarization of 5 V during irradiation the pMOS dosimeters can be re-used for measurements of the irradiation dose after annealing without prior calibration. The pMOS dosimeters with the gate polarization during irradiation of 2.5 V can also be re-used for irradiation dose measurements but they require calibration. It is shown that for their re-use it is necessary to anneal the pMOS dosimeter so that the fading is higher than 50%. [Projekat Ministarstva nauke Republike Srbije, br. 171007

Pejovi? Mili? M.

2012-01-01

45

Performance of randomly distributed holes optical fibers under low dose gamma-ray irradiation  

Science.gov (United States)

This article presents the effect of low-dose gamma-ray irradiation on a newly developed randomly distributed holes optical fiber (RDHF). The single-mode fiber has a cladding diameter of 125 ?m and 0.21 dB/km attenuation in the 1550 nm wavelength. The effect of gamma irradiation on the presented fibers was studied by comparing their transmission performance at 1550 nm wavelength with standard single-mode telecommunication fiber (SMF). RDHF along with SMF were irradiated with 0.662 MeV gamma-rays at absorbed dose rate of 4 mGy(Si)/hr and total dose of 1.5 Gy(Si). Results revealed that the performance of optical fiber under irradiation is not only dependent on the bulk material but also on the physical structure of the fiber.

Alfeeli, Bassam; Narayanan, Shree; Smiley, Doug; Conner, Donald; Pickrell, Gary

2011-03-01

46

Coloring of cultured pearls by gamma-rays irradiation  

International Nuclear Information System (INIS)

Changing cream pearls into bluish-grey by ? ray irradiation is a technique in coloring of pearls. Irradiated pearls are similar in color to cultured blue pearls. The pearl layers hardly change their color but the nuclei change into dark brown by irradiation. Visible light (500 - 700 nm) penetrating the pearl layer is absorbed by dark brown nucleus. The intensity of reflecting light between 400 and 500 nm at pearl surface, therefore, becomes stronger than that between 500 and 700 nm; therefore color of irradiated pearls look bluish-grey. The density of bluish-grey color increases with increasing absorbed doses, but their luster at surface diminishes owing to the deterioration of the pearl layer by prolonged irradiation; high doses irradiation should be avoided. Irradiated pearls show no substantial fading of their color in a year and the rate of the fading is found to be lower than that for cultured blue pearls. (author)

47

Endurance of cultured pearls irradiated with gamma-rays  

International Nuclear Information System (INIS)

Pearls change their color to grey by ?-ray irradiation. Grey densities were determined from darkness of pearl nuclei and thickness of the pearl layers. The densities are independent of both diameters of nuclei and pearls. The fading rate increases with increasing storage temperature. The rate of fading for irradiated pearls is lower than that for natural blue pearls. Comparison of photomicrographs (x 12) for pearls irradiated and then stored at room temperature for about 6 years revealed that their surfaces are not substantially different from the surfaces of unirradiated cultured pearls, indicating that ? irradiation hardly gives rise to deterioration. ?-Ray irradiation is a technique for coloration of pearls. Irradiated blue pearls seem to have resistivity to fading and to deterioration of the surface, if pearls have been irradiated properly. (author)

48

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)

49

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

International Nuclear Information System (INIS)

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

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

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

52

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

53

Hydrogen loss from elastomers subjected to ion irradiation  

Energy Technology Data Exchange (ETDEWEB)

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

Jagielski, J., E-mail: jacek.jagielski@itme.edu.pl [Institute for Electronic Materials Technology, Wolczynska 133, 01-926 Warszawa (Poland); The Andrzej Soltan Institute for Nuclear Studies, 05-400 Swierk/Otwock (Poland); Grambole, D. [Institut of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, PO Box 51 01 19, D-01314 Dresden (Germany); Jozwik, I. [Institute for Electronic Materials Technology, Wolczynska 133, 01-926 Warszawa (Poland); Bielinski, D.M. [Institute for Engineering of Polymer Materials and Dyes, Division of Elastomers and Rubber Technology, Harcerska 30, 05-820 Piastow (Poland); Technical University of Lodz, Institute of Polymer and Dye Technology, Stefanowskiego 12/16, 90-924 Lodz (Poland); Ostaszewska, U.; Pieczynska, D. [Institute for Engineering of Polymer Materials and Dyes, Division of Elastomers and Rubber Technology, Harcerska 30, 05-820 Piastow (Poland)

2011-05-16

54

Hydrogen loss from elastomers subjected to ion irradiation  

International Nuclear Information System (INIS)

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

55

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.)

56

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

57

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

58

Functional and morphological changes of rat platelets following whole body gamma-ray irradiation  

International Nuclear Information System (INIS)

Changes in platelet count, ability for platelet aggregation and adhesiveness as well as morphological changes in the platelets were investigated in rats following whole body gamma -ray irradiation at a dose of 700 - 800 R: 1) The platelet counts varied with time after irradiation in a triphasic manner expressed by a flattened v-shape. The control value of the platelet count was 919,000/mm3. It increased to as much as approximately 1,200,000/mm3 on the 3rd day, and then fell sharply to a level of less than 10,000/mm3 on the 10th day, indicating severe thrombocytopenia, but again tended to rise to a level of approximately 100,000/mm3, indicating a recovery state. 2) A marked decrease in ADP-induced platelet aggregation was seen on the 3rd day after gamma -ray irradiation. However, it was restored to around half the level in the control group thereafter. The platelet adhesiveness was observed to change in parallel with the variation in pattern of the platelet count. 3) Platelets of more than 4 mu in diameter were observed to appear in the peripheral blood of the gamma -ray irradiated rats. In particular, giant platelets of more than 5 mu in size represented 14 - 20% of the total platelet count. The protoplasm of such giant platelets was basophilic, and intracellular azurophilic granules were evident. (author)

59

ESR study of ascorbic acid irradiated with gamma-ray  

International Nuclear Information System (INIS)

The interest in application of high-energy ionizing radiation for sterilization of pharmaceutical products and foodstuffs has led a number of workers to investigate the radiation sensitivity of vitamins. Aside from its use as a vitamin, ascorbic acid (AA) or some derivatives are employed as antioxidants in foodstuffs. The effects of ionizing radiation on AA in simple solutions and in mixture of naturally occurring compounds have been extensively reported in the literature. However, the effects of ionizing radiation on solid AA were reported in few works which described rather dosimetric features of AA. No reports, except one, are available describing the characteristic features of the radiolytic intermediates produced after irradiation of polycrystalline AA. Irradiation studies performed on single crystal of AA has led us to reinvestigate our previous work on the radiolytic intermediates produced in irradiated polycrystalline AA. Three radical species, rather than two, having different characteristics were decided contributing to the formation of experimental electron spin resonance (ESR) spectrum of ?-irradiated polycrystalline AA. Spectral parameters of these species were calculated after exhaustive spectrum simulation calculations based on data derived from experimental microwave saturation and dose-response studies. (author)

60

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

 
 
 
 
61

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.)

62

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)

63

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)

64

Local laser-decolorizing of gamma-ray irradiated silicate glass  

Science.gov (United States)

Local decolorizing of gamma-ray irradiated silicate glasses has been studied under thermal annealing by a laser beam. The influence of the beam's exposure time was studied, showing that an increase of the glass temperature on the irradiated areas can locally induce complete decolorizing (bleaching) of glass. In this work, the heat conduction differential equation is solved by numerical approach using the finite element method and results are compared by experimental analysis. Although much work is being developed in the fields of color centers creation and its decay by heat, this work presents the first systematic study on near-infrared decolorizing of gamma-irradiated float silicate glasses.

Coelho, Joa~O. M. P.; Silva, Catarina; Ruivo, Andreia; Botelho, Maria Luísa; de Matos, António Pires

2011-06-01

65

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

66

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

International Nuclear Information System (INIS)

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

67

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)

68

The role of {sup 60}Co gamma-ray irradiation on the interface states and series resistance in MIS structures  

Energy Technology Data Exchange (ETDEWEB)

The effect of gamma-ray exposure on the metal-insulator-semiconductor (MIS) structures has been investigated using the electrical characteristics at room temperature. The MIS structures are irradiated with {sup 60}Co gamma-ray source. The energy distribution of interface states was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height and ideality factor. The value of series resistance decreases with increasing dose. Experimental results confirmed that gamma-ray irradiation have a significant effect on electrical characteristics of MIS structures.

Tascioglu, Ilke [Department of Physics, Faculty of Science and Arts, Gazi University, 06500 Ankara (Turkey); Tataroglu, Adem, E-mail: ademt@gazi.edu.t [Department of Physics, Faculty of Science and Arts, Gazi University, 06500 Ankara (Turkey); Ozbay, Akif; Altindal, Semsettin [Department of Physics, Faculty of Science and Arts, Gazi University, 06500 Ankara (Turkey)

2010-04-15

69

Effects of gamma-ray irradiation on the high temperature oxidation of austenitic stainless steel in supercritical water  

International Nuclear Information System (INIS)

Three types of commercial-grade austenitic stainless steel, Type 304L, Type 316L, and Type 310S, were immersed in deaerated supercritical water (SCW) of 25 MPa, 550degC with gamma-ray irradiation for 1000 hours in total. Absorbed dose rates in SCW are estimated at 5-15 kGy h-1. High temperature oxidation experiments resulted in the formation of two-layer oxide film in which the outer layer is porous iron oxide and the inner layer is dense iron-chromium-nickel oxide. Rate constants of parabolic rate law in net weight gains of Type 304L SS and Type 310S SS are decreased as the gamma-ray exposure rate is increased. The net weight gain of gamma-ray irradiated Type 316L SS is sharply fluctuating and decreasing, because the flaking of the outer layer occurred. Hematite is formed in the outer layer on all irradiated samples of examined alloys. The concentration of chromium on the surface is increased by gamma-ray irradiation. A chromium-rich part in the inner layer accompanying a nickel-rich part in the metal is formed along to the oxide/metal interface of gamma-ray irradiated Type 304L SS, non-irradiated and gamma-ray irradiated Type 316L SS. (author)

70

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

71

Gamma ray spectra from targets irradiated by picosecond lasers  

Science.gov (United States)

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

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

2011-09-01

72

Gamma-ray irradiation effects on some electronic devices used in control circuits  

International Nuclear Information System (INIS)

The influence of gamma-ray irradiation on some electronic devices that are frequently used in most kinds of electronic circuits and apparatus was investigated. Before irradiation the I-V characteristic of the diodes and transistors and the time of the logical gates were measured. The devices were irradiated in 6 steps (1, 2, 2, 2, 3, 5 Mrads). the final total dose was 15 Mrads. The I-V characteristic and the delay time were measured after every irradiation step and compared with the measurements before irradiation. The above mentioned measurements were performed several times with different time distances after the final irradiation step in order to investigate the stability of the effects induced by irradiation. (author)

73

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Widiastuti A, Sobir, Suhartanto MR. 2010. Diversity analysis of mangosteen (Garcinia mangostana L.) irradiated by gamma-ray based on morphological and anatomical characteristics. Nusantara Bioscience 2: 23-33. The aim of this research was to increase genetic variability of mangosteen (Garcinia mangostana L.) irradiated by gamma rays dosage of 0 Gy, 20 Gy, 25 Gy, 30 Gy,35 Gy and 40 Gy. Plant materials used were seeds collected from Cegal Sub-village, Karacak Village, Leuwiliang Sub-district, B...

MUH RAHMAD SUHARTANTO; SOBIR; ALFIN WIDIASTUTI

2010-01-01

74

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

International Nuclear Information System (INIS)

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

75

Dielectric properties of wood irradiated with gamma-rays  

International Nuclear Information System (INIS)

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

76

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

Energy Technology Data Exchange (ETDEWEB)

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)

Polf, J C; Peterson, S; Beddar, S [M D Anderson Cancer Center, Univeristy of Texas, Houston, TX 77030 (United States); McCleskey, M; Roeder, B T; Spiridon, A; Trache, L [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States)], E-mail: jcpolf@mdanderson.org

2009-11-21

77

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

78

NOTE: 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.

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

2009-11-01

79

EPR and UV investigation of sucrose irradiated with nitrogen ions and gamma-rays  

Energy Technology Data Exchange (ETDEWEB)

Sucrose irradiated with N-ions and gamma-rays is investigated by EPR and UV spectroscopy. Irradiation doses are in the range of 20-380 Gy and linear energy transfer (LET) for N-ions of 90, 125 and 160keV{mu}m{sup -1}. All EPR spectra recorded in irradiated solid samples are identical, suggesting that generated free radicals are not sensitive to the radiation quality. The EPR response of free radicals linearly depends on the absorbed dose but when generated by N-ions it is always lower than that obtained by irradiation with the same absorbed dose from gamma-rays. Water solutions of irradiated sucrose exhibit UV absorption at 267 nm due to the product of free radicals recombination, which spectrum remains independent on the radiation quality. The intensity of this band however depends on the absorbed dose and for equal doses it is higher for samples irradiated with N-ions than with gamma-rays. For different high LET-radiations with N-ions and low-LET radiation from gamma rays is found an excellent linearity between the EPR signal intensity and the UV absorbance of the obtained water solution. The relation between EPR and UV response of N-ions irradiated samples is reciprocal as well as between them and gamma-irradiated samples suggesting different impact of the high-energy photons and heavy particles on the solid state. For low LET photon radiation with moderate dose rate the probability for a successful hitting of two neighboring molecules is low. Therefore, only a small part of low LET radiation-induced free radicals may be expected to recombine giving an UV detectable product. In opposite, because of the dense ionizations and heaviness of N-ions almost all molecules in the core of the track are ionized yielding mainly products of the recombined free radicals. In the outer part of the track delta particles, which are more like low LET radiation electrons, stands for ionizations and produces a small number of free radicals situated far from each other. Therefore, we can expect higher EPR response of sugar irradiated with a certain dose of gamma-rays than of heavy particles. Just the opposite behavior should be expected for the UV absorption, which should be higher in the irradiation with heavy particles than with gamma-rays. The reported observations suggest that a sucrose/UV/EPR dosimetric system seems to be very promising for dose determinations from both gamma and heavy particle radiation and indicate a method for simultaneous determination of absorbed dose and LET. It also seems to be a new way for calibration of EPR dosimeters irradiated with N-ions via UV spectrometry.

Karakirova, Yordanka [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Lund, Eva [Department of Radiation Physics, IMV, Faculty of Health Sciences, SE-58185 Linkoping (Sweden); Yordanov, Nicola D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)], E-mail: ndyepr@bas.bg

2008-09-15

80

Gamma Ray Irradiation Effects on the Ferroelectric and Piezoelectric Properties of Barium Titanate Ceramics  

Science.gov (United States)

The effect of heavy dose gamma ray irradiation on the ferroelectric and piezoelectric properties of barium titanate (BaTiO3) ceramics has been investigated. It is found that on irradiation the ferroelectric property decreases and polarization behavior shows double loop hysteresis. The piezoelectric properties including piezoelectric charge constant ( d 33), electromechanical coupling coefficient ( K p), and electrostrictive strain also decreases. The most probable reason for decreased ferroelectric and piezoelectric properties may be the occurrence of random local strain upon irradiation. The phase transition temperature from ferroelectric to paraelectric decreases and degree of diffuseness increases on irradiation. The thermoluminescence (TL) glow curve showed a peak at 226 °C showing that irradiated BaTiO3 has TL properties. Presence of TL clearly indicates that gamma ray irradiation causes trapped holes and electrons and these trapped charges are released at temperature higher than 226 °C. The creation of trapped holes and electrons effected the microstrain of BaTiO3 ceramic leading to change in the ferroelectric and piezoelectric properties of BaTiO3 ceramic.

Medhi, Nirmali; Nath, A. K.

2013-09-01

 
 
 
 
81

Deep Hole Traps Created by Gamma-Ray Irradiation of GaInP  

Science.gov (United States)

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

Sung, Wei-Jer; Liu, Tong-Yuan; Yang, Su-Lin; Huang, Kai-Feng; Tseng, Tseung-Yuen; Chou, Fong-In; Wei, Yuan-Yaw

2001-12-01

82

Deep hole traps created by gamma-ray irradiation of GaInP  

International Nuclear Information System (INIS)

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

83

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)

84

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 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

85

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

86

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)

87

Annealing effects on the rise time of gamma-ray irradiated Au-Si nuclear detectors  

International Nuclear Information System (INIS)

Thermal annealing effects on silicon surface barrier nuclear detectors damaged with radiation are investigated by measuring output rise time and induced defect densities. Silicon wafers as materials of the detectors are irradiated with gamma-rays of 60-Co, and then the irradiated silicon specimens are annealed thermally. The rise time measurement for 241-Am alpha-particles incidence is performed by using a digital system. It is observed that the rise time of the annealed detectors becomes faster than that of the irradiated detectors. The induced defect densities, measured with DLTS method, are reduced to about 1/2 the amount of irradiated detectors, for annealing temperature 420K, 60 minutes. The characteristics of the detectors irradiated with less than 1X107R are almost recovered in accordance with the decrease of defect densities

88

Bremsstrahlung {gamma}-ray generation by electrons from gas jets irradiated by laser pulses for radiographic testing  

Energy Technology Data Exchange (ETDEWEB)

Electron generation from a gas jet irradiated by low energy femtosecond laser pulses is studied experimentally as a promising source of radiation for radioisotope-free {gamma}-ray imaging systems. The calculated yield of {gamma}-rays in the 0.5-2 MeV range, produced by low-average-power lasers and gas targets, exceeds the yields from solid tape targets up to 60 times. In addition, an effect of quasi-mono energetic electrons on {gamma}-ray imaging is also discussed.

Oishi, Yuji; Nayuki, Takuya; Zhidkov, Alexei; Fujii, Takashi; Nemoto, Koshichi [Central Research Institute of Electric Power Industry, Yokosuka, Kanagawa 240-0196 (Japan); Central Research Institute of Electric Power Industry, Yokosuka, Kanagawa 240-0196, Japan and Photon Pioneers Center in Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Central Research Institute of Electric Power Industry, Yokosuka, Kanagawa 240-0196 (Japan)

2012-07-11

89

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

Science.gov (United States)

The effects of neutron 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 10(exp 13) n/sq cm 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 presented. 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.

Schwarze, G. E.; Frasca, A. J.

1991-09-01

90

Effect of N-acetyl-l-cysteine on Saccharomyces cerevisiae irradiated with gamma-rays.  

Science.gov (United States)

Ionizing radiation (IR) induces DNA strand breaks (DSBs), base damage, inhibition of protein activity, apoptosis by reactive oxygen species (ROS). Detoxification or removal of generated ROS can reduce oxidative damage. Antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase are immediately triggered for ROS scavenging. N-acetyl-l-cysteine (NAC) having a thiol, a precursor for reduced glutathione (GSH), is known as one of the antioxidants. In this study, the effect of NAC as an antioxidant and a radioprotector was investigated on survival rate, transcriptional level of antioxidant enzymes gene, and protein level including SOD activity and intracellular GSH in yeast Saccharomyces cerevisiae W303-1A strain mutated YBP1 gene irradiated with gamma-rays. NAC did not protect the gamma-ray-induced cell death. The gene expression of antioxidant enzymes including SOD1, SOD2, GPX1, and GPX2 was induced by gamma-rays. In contrast, the pretreatment of NAC reduced the expression of these genes. NAC reduced SOD activity and intracellular GSH level in yeast. These data suggest that NAC is able to reduce radiation-induced ROS levels in vivo but does not protect yeast cells against radiation-induced death. PMID:23623538

Kim, Jin Kyu; Park, Jiyoung; Ryu, Tae Ho; Nili, Mohammad

2013-07-01

91

Gas yield and mechanical property of super insulator (polyimide and polyester) after gamma ray irradiation  

International Nuclear Information System (INIS)

Japanese intense spallation neutron source (JSNS) driven by 3 GeV protons with power of 1 MW is constructed under the joint project of Japan Atomic Energy Agency and High Energy Accelerator Research Organization. Supercritical hydrogen of around 20K with 2 MPa is selected as a neutron moderator material and cryogenic hydrogen transfer lines are constructed from the moderators to the refrigerator. Then, a super insulator (SI) is adopted to reduce heat load in the hydrogen transfer lines. We performed irradiation test of SI using 60Co gamma ray to evaluate the irradiation effect. Two kinds of super insulator (polyimide and polyester) coated both sides by aluminum with thickness of 5 x 10-8 m were irradiated. After gamma ray irradiation, tensile test and gas yield measurement of super insulator were performed. Polyster based SI became brittle at about 10 MGy, on the other hand, polyimide based SI did not loss ductility so much even 80 MGy. Polyester based SI generated gas yield higher than that of polyimide based SI about one order of magnitude. We developed the gas analysis method by using a Q-mass and a mass-flow, providing to identify the unknown gas (i.e. H2O) effectively compared to a gas chromatography method. (author)

92

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.)

93

High density polyethylene membrane filled with alumina prepared by a gamma ray irradiation.  

Science.gov (United States)

High density polyethylene (HDPE) membrane filled with alumina particles was prepared by a wet process for a Li-ion secondary battery. Soybean oil and dibutyl phthalate (DBP) were premixed as the co-diluents. Gamma ray irradiation was used for crosslinking of HDPE. The HDPE membrane filled with alumina particles had excellent mechanical property and thermal stability due to the alumina particles and irradiation crosslinking. The tensile strength of the membrane increased with an increased amount of alumina up to 15 wt%. The thermal shrinkage of the membrane decreased with an increased amount of alumina up to 15 wt%. The electrochemical stability of the irradiated membrane after extraction was improved with irradiation dose up to 50 kGy. PMID:22103225

Park, Jong-Seok; Sung, Hae-Jun; Lim, Youn-Mook; Gwon, Hui-Jeong; Nho, Young-Chang

2011-08-01

94

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

International Nuclear Information System (INIS)

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

95

Effects of single 60Co gamma rays irradiation on antibody forming cells  

International Nuclear Information System (INIS)

The male and female mice were irradiated with different doses (from 0 to 200 cGy) of 60Co gamma ray, their splenic antibody forming cells were measured with the Plaque Forming Cell (PFC) technique. The results show that the PFCs of both the male and female mice were depressed and the depression was of dose-depending. When the dose was 200 cGy, about 85% of the PFCs were inhabited. No difference in the radiosensitivity between the male and female mice was found

96

Effect of neutron and gamma-ray irradiation on the transmittance power of glasses and glues  

Energy Technology Data Exchange (ETDEWEB)

LHC, working at the expected nominal luminosity, will induce an extremely high irradiation in the CMS experiment. The CMS alignment system uses optical elements to build the laser beams paths. Optical properties of basic components such as glasses and glues may be affected and their transmission power may degrade significantly. We have proceeded to a first test of various glasses and glues and identified some of them that can stand up to 150 kGy of gamma-rays plus 5x10{sup 14} neutrons/cm{sup 2}.

Beigveder, J.M.; Genova, I.; Perez, G.; Ruiz, J.A.; Arce, P.; Barcala, J.M.; Fernandez, M.G.; Ferrando, A. E-mail: ferrando@ae.ciemat.es; Fuentes, J.; Josa, M.I.; Molinero, A.; Oller, J.C.; Calvo, E.; Figueroa, C.F.; Rodrigo, T.; Vila, I.; Virto, A.L.; Fenyvesi, A.; Molnar, J.; Sohler, D

2002-11-11

97

Thermoluminescence characteristics of an Egyptian igneous granite rock before and after beta and gamma ray irradiation  

International Nuclear Information System (INIS)

Samples of granite rock taken from Wadi El-Nafh area (Sinai-Egypt), exhibit relatively strong thermoluminescence (TL) glow curves. With a series of beta and gamma-ray irradiation and thermal treatments, the TL characteristics were investigated. The results indicate that the heating up to 1000 degree C for one hour and immediate quenching in ice are the optimum conditions for maximum sensitization of the samples. Under these conditions, the enhanced TL efficiency (S/S) for the investigated granite was increased by a factor of 42.4. 8 figs., 2 tabs

98

EPR and UV investigation of sucrose irradiated with nitrogen ions and gamma-rays  

International Nuclear Information System (INIS)

ring molecules is low. Therefore, only a small part of low LET radiation-induced free radicals may be expected to recombine giving an UV detectable product. In opposite, because of the dense ionizations and heaviness of N-ions almost all molecules in the core of the track are ionized yielding mainly products of the recombined free radicals. In the outer part of the track delta particles, which are more like low LET radiation electrons, stands for ionizations and produces a small number of free radicals situated far from each other. Therefore, we can expect higher EPR response of sugar irradiated with a certain dose of gamma-rays than of heavy particles. Just the opposite behavior should be expected for the UV absorption, which should be higher in the irradiation with heavy particles than with gamma-rays. The reported observations suggest that a sucrose/UV/EPR dosimetric system seems to be very promising for dose determinations from both gamma and heavy particle radiation and indicate a method for simultaneous determination of absorbed dose and LET. It also seems to be a new way for calibration of EPR dosimeters irradiated with N-ions via UV spectrometry

99

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%

100

Destruction of 1,1-dichloroethylene/air mixture under gamma-ray irradiation  

International Nuclear Information System (INIS)

Radiation-induced decomposition of 1,1-dichloroethylene(1,1-DCE) in air was investigated in the experiment. The model gas prepared by mixing 1,1-dichloroethylene vapor with air was sealed in batch reactors and subjected to gamma irradiation. Inorganic products (CO + CO2) and organic products were analyzed by means of a TOC analyzer and gas-chromatography, respectively. It was found that chloroacetyl chloride (CH2ClCOCl) was present as the main organic product while inorganic products (CO + CO2) occurred in quantities below 10% based on relative carbon balance. Energy consumption of 1,1-DCE by using gamma-ray irradiation was compared with that by using electron beam irradiation. (orig.)

 
 
 
 
101

Photocatalytic activity of titanium dioxide prepared by a gamma-ray irradiation  

International Nuclear Information System (INIS)

The photocatalytic activity of titanium dioxide prepared by a gamma-ray irradiation was investigated. The particles of the prepared TiO2 were very fine and had a narrow distribution. The particle size of the prepared TiO2 was in the range 20-100 nm and the average particle size was 61 nm from the particle size analyzer (PSA) result. The remaining ammonia gas after a UV irradiation was measured. Ammonia gas detection and analysis were carried out on a capillary column-gas chromatography (GC) system. The remaining ammonia gas of the prepared sample in a transparent tube after a UV irradiation was decreased owing to the neutralization reaction of the ammonium hydroxide and polyacrylic acid (PAC) and the photocatalytic activity of the nanosized TiO2 particles.

102

Photocatalytic activity of titanium dioxide prepared by a gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

The photocatalytic activity of titanium dioxide prepared by a gamma-ray irradiation was investigated. The particles of the prepared TiO{sub 2} were very fine and had a narrow distribution. The particle size of the prepared TiO{sub 2} was in the range 20-100 nm and the average particle size was 61 nm from the particle size analyzer (PSA) result. The remaining ammonia gas after a UV irradiation was measured. Ammonia gas detection and analysis were carried out on a capillary column-gas chromatography (GC) system. The remaining ammonia gas of the prepared sample in a transparent tube after a UV irradiation was decreased owing to the neutralization reaction of the ammonium hydroxide and polyacrylic acid (PAC) and the photocatalytic activity of the nanosized TiO{sub 2} particles.

Nho, Young-Chang [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of)], E-mail: ycnho@kaeri.re.kr; Park, Jong-Seok; Youn, Jong-Kyu; Lim, Youn-Mook; Shin, Jun-Hwa [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of)

2009-07-15

103

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

International Nuclear Information System (INIS)

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

104

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

105

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)

106

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

International Nuclear Information System (INIS)

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

107

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

108

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)

109

Dynamics of nitrite-induced methemoglobin formation after total gamma-ray irradiation of rats  

International Nuclear Information System (INIS)

One trend in the design of atomic power stations (APS) based on fast neutrons is the development of APS in which dissociating nitrogen tetroxide is used as heat carrier and as working heat. Here, the authors study the combined action of ionizing radiation and of sodium nitrite on methemoglobin formation associated with the action of nitrites as a metabolic product of nitrogen oxide metabolism. Experiments were carried out on male Wistar rats weighing 180-200 g. Single whole-body irradiation was given on the UGU-420 gamma-ray source in doses of 77.4 and 180.6 mCi/kg body weight. The dynamics of changes in the methemoglobin concentration was monitored on a VSU-2-P spectrophotometer at 540-630 nm. A diagram showing the relationship between nitrite-induced methemoglobin formation and dose and time elapsing after irradiation is shown

110

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)

111

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

International Nuclear Information System (INIS)

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

112

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 150°C 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 150°C 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

113

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.

114

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

CERN Document Server

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

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

2005-01-01

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

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

International Nuclear Information System (INIS)

An agglutinability between naturally infected positive chicken serum of pullorum disease and hyperimmunized rabbit antiserum was compared. And the following results were obtained and summarized. On the agglutinability, Salmonella pullorum antigen which irradiated gamma-ray was better than another both formalized and heated antigen. Time of judgemented as positive titer in the tube agglutination test to the naturally infected positive chicken serum was it most suitable for 12 hours at 370C. Agglutination titer of positive immune chicken serum against gamma-ray irradiate Salmonella pullorum were as 320 approximately 640x. (author)

117

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

International Nuclear Information System (INIS)

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

118

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 32±2oC for 3 days. The survival colonies were calculated,and the data were used to make the curve and to determine the D10 value. The results of the experiments showed that D10 value of irradiated bacteria of P.aeruginosain the disitilled water,talc and peanut powder as carrier were not high significant.Nevertheless the D10 value of the irradiated at dose rate 10kGy/h show more higher tendency than at dose rate 5kGy/h. The D10 value of irradiated bacteria in the N2 condition was higher,if compared with in the O2 condition

119

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.

120

Sterilizing efficiencies of high energy electrons and gamma rays and judgment of irradiation history of medical products  

International Nuclear Information System (INIS)

Polymer materials, used for medical products, were irradiated with gamma rays or with high energy electron beams, then the post-irradiation changes of radical concentrations in those materials were examined with a electron spin resonance spectroscopy. As the radical concentrations in polystyrene, silicon and some of polypropylene samples formed by gamma ray irradiation, and those in polystyrene, polyvinyl chloride and some of polypropylene samples formed by electron beam irradiation, were decreased rapidly, it was difficult to judge whether those materials were irradiated in the past days or not. However, radical concentrations in the other materials were high enough to measure even two years after irradiation. The radicals, resided in polypropylene needle cups after 5-11 months after irradiation, were relatively stable. The radical concentrations in the needle cups were higher in the case of gamma ray irradiation than electron beam irradiation. The radical concentrations in the needle cups about 4 years after irradiation, increased rapidly by heat treatment but those in non-irradiated needle cups increased a little. The changes of radical concentrations in polypropylene model samples, polytetrafluoroethylene and alanine dosimeter were examined, too. (author)

 
 
 
 
121

Gamma ray irradiation behavior of fission products in nitric acid solution  

International Nuclear Information System (INIS)

Redox behaviors of some dissolved species such as ruthenium, cerium, and chromium have been experimentally investigated in nitric acid solutions under gamma ray irradiation. Solutions containing chemical species of high or low valence states and nitric acid concentrations of 3 and 9 mol/L were irradiated by a 60Co gamma ray source (104 Gy/h, 106 rad/h) in beaker-scale apparatuses at room and boiling point temperatures. Concentration changes of the species after gamma-irradiation were compared with those of non-irradiated samples to determine the effect of radiation. By irradiation of the solution containing higher valent species, Ce(IV), Ru(VIII), and Cr(VI) were reduced to their lower valent ones. In the case of irradiation of the solution containing lower valent species, oxidation rates of Ce(III), Ru(II), and Cr(III) to Ce(VI), Ru(VIII) and Cr(VI) were lowered. It was found that the equilibrium for the Ce(IV)/Ce(III) redox couple shifted to the lower valence side with the irradiation. The effect of radiation saturated beyond the dose rate of 10 Gy/h (103 rad/h) for the redox equilibrium of Ce(IV)/Ce(III) couple, although the initial reduction rate of Ce(IV) increased with the dose rate beyond 10 Gy/h. While the reductions were in progress for higher valent species, nitrous acid was not detected. An increase of nitrous acid concentration was found when the concentration of the higher valent species reached the redox equilibrium value. The initial reduction rates of the higher valent species agreed well with the evaluated formation rate of nitrous acid in the irradiated nitric acid solution. Therefore, the reduction of the higher valent species and decrease of oxidation rate of lower valent species did not occur due to a radiolysis product from water, but occurred due to nitrous acid or nitrogen dioxide, which were the main products from the radiolysis of nitric acid solution. (author)

122

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-05-15

123

Response of cancer stem-like cells and non-stem cancer cells to proton and {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Ionizing radiation is a widely used therapy for solid tumors. Compelling evidence indicates cancer stem-like cells (CSCs) exist in solid tumors, which is on the top of hierarchically organization and suggested to be involved in carcinogenesis, tumor invasion, recurrence and resistance to various forms of therapies. Understanding the response of CSCs to irradiation is of great importance to improve cancer curability. In present study, the response to proton and {gamma}-ray irradiation of these cells, including DNA damage and apoptosis were investigated experimentally. The results show that CSCs have higher resistance than non-stem cancer cells (NSCCs) to either proton or {gamma}-ray irradiation. In addition, compared with {gamma}-ray, proton irradiation is more efficient to kill CSCs at the same dose with lower survival as well as higher DNA damages. The results suggest that proton irradiation may have greater capability of eliminating CSCs for cancer radiotherapy than {gamma}-ray at the same dose, which in turn makes radiotherapy more efficient.

Fu Qibin; Quan Yi; Wang Weikang; 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); Ren Xiaotang; Xue Jianming; Wang Yugang [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)

2012-09-01

124

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)

125

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

International Nuclear Information System (INIS)

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

126

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

127

Simulation technique on dose-rate distribution in a 60Co gamma-ray irradiation field  

International Nuclear Information System (INIS)

Dose-rate distribution in irradiation field of 60Co gamma-ray was calculated using Monte Carlo photon transport code named as EGS4-SPG code. The dose rate values measured by the ionization chamber and the alanine dosimeter were compared with calculated ones for the evaluation of the validity of the calculation. As a result, the difference between measurements and the calculation value was within ± a few% except for a position very near the source for a wide board radiation source. The dose-rate distribution can be estimated using these numerical results at the beforehand planning of a board radiation source arrangement although dose-rate measurement should be done only for a position very near the radiation source, where calculated value disagreed. The dose rate distribution measurement after the radiation source arrangement enables us to save number of the dosimeter and measurement time. (author)

128

Aqueous solution of iodide under gamma ray irradiation - fixation of iodide by adding soluble silver salt  

International Nuclear Information System (INIS)

An experiment on the fixation of iodide by adding soluble silver salt in the aqueous solution under the gamma ray irradiation was performed to establish a method for confinement of methyl iodide formation during the severe accident of a LWR plant. The formation of methyl iodide in the water phase of sump tank in the reactor pressure vessel containment building was presumed in this study by the reason of being of much obscure parts on the formation mechanism and transfer behavior of the methyl iodide under the severe accident conditions. And the separate effects tests on the chemical behavior of silver iodide and methyl iodide were performed under the gamma ray irradiation. Though the high dependence on the accident events sequence or the plant construction for the formation and transfer behavior of the fission products iodine was inferred, it was shown from the experimental results as above that the method to confine the formation of the methyl iodide by adding the soluble silver salt into the sump tank water at the accident is desirable. In conclusion: The cobalt 60 gamma ray irradiation (1.3 x 106 R/h x 2.75 h) to the silver iodide just after the precipitation in the aqueous solution did not give the effect to the stability of the precipitate. The aqueous solutions shut up in the stainless steel bombs as below were irradiated by the gamma ray from the spent fuel assembly(6.6 or 6.9 x 105 R/h, 1 or 2 h), respectively; CsI (7.89 x 10-4 M), CsI (7.69) x 10-5?7.89 x 10-4 M) containing (COOH)2(5.56 x 10-5 M ?1.11 x 10-3 M), H3BO3(3.24 x 10-2 M) and CH3COOH (1.67 x 10-5 M?1.67 x 10-3 M), Fe3+ (1.79 x 10-3 M) and (COOH)2(2.2 x 10-4 M), or CsOH (3.2 x 10-6 M) and CH3COOH (1.67 x 10-5?1.67 x 10-3 M), respectively. The methyl iodide occurred in each bomb just, after the irradiation(max. 2.7 x 10-1 %), but the formation mechanism of methyl iodide in each solution above were not resolved. The methyl iodide dissolved in the aqueous solutions(6.44 x 10-2 M) were irradiated by the cobalt 60 gamma ray (1.4 x 106 R/h x 4 h), respectively. Thirty two % of the methyl iodide above(in average of 4 data) were decomposed to the iodine (I2) and the iodide (I-). The decomposition rate of methyl iodide dissolved in the aqueous solution was greater than that in the gaseous state, apparently. In the aqueous solution shut up in the glass container, the methyl iodide was formed from the reaction between the methyl radical donor(dimethyl sulfate, 1 x 10-3 M or 2 x 10-3 M) and the iodine-131 tracer(about 7 micro Ci) at the conversion rate of about 3.5 %. In the aqueous solution above, the formation of methyl iodide decreased distinctly by the cobalt 60 gamma ray irradiation (7 x 105 R/h x 1 h) or the addition of the silver nitrate (1 x 10-4 M). Under the severe accident conditions of LWR, when the main source of methyl iodide formation is due to the reaction between the methyl radical donor and the soluble fission products iodide(containing the iodine formed from the reaction between the oxidation products by water radiolysis and the iodide ion), the addition of adequate amounts of silver nitrate to the water phase just before the dissolution of soluble fission products iodine can decrease distinctly the formation rate of methyl iodide by producing the silver iodide precipitate. (author)

129

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

130

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

International Nuclear Information System (INIS)

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

131

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

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

MUH RAHMAD SUHARTANTO

2010-01-01

132

Comparative study of gamma-ray and neutron irradiated laser diodes  

Science.gov (United States)

A set of applications of interest for semiconductor lasers constitutes their use under irradiation conditions in nuclear power plants, radiation processing facilities, high energy physics accelerators, nuclear waste management sites, or even space crafts. One such an example is the task related to remote handling and control in fusion installations (i.e. ITER - the International Thermonuclear Experimental Reactor). The paper reports our results on the irradiation effects on different semiconductor laser structures, emitting at 850 nm, 1310, 1550 nm, as they were subjected either to gamma-ray (total dose of 1.5 MGy) or neutron irradiation (total fluence of 10 13 n/ cm2 ), in the frame of the European Union's Fusion Program. The electrical, optical and optoelectronics characteristics (the optical power vs. the driving current of the semiconductor laser; the embedded photodiode current vs. the emitted optical power; the direct voltage vs. the driving current, the external quantum efficiency, the serial resistance, the photodiode responsivity) were monitored under these conditions. All the investigated devices were commercially available products. The irradiations were done at room temperature, and the measurements were carried off-line.

Sporea, Dan; Sporea, Adelina; Vata, I.

2007-06-01

133

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

134

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

International Nuclear Information System (INIS)

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

135

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

International Nuclear Information System (INIS)

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

136

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.

137

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

Science.gov (United States)

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 2O 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; Michael, Pratik E. P.; Kokate, M. V.; Tabhane, V. A.

2012-02-01

138

Mechanical properties and molecular weight distribution changes of low density polyethylene caused by gamma-ray and electron beam irradiation  

International Nuclear Information System (INIS)

Gamma-ray and electron beam irradiated low density polyethylene (LDPE) films were obtained, and their structural changes and mechanical property changes were examined. In the electron beam irradiation sample, it was found that part of the crystal structure collapses in the initial stage by the irradiation, and then the molecular chain in the amorphous phase seems to generate the recrystallization from the result of the change of heat of fusion. At the same time, the trans vinylidene group, which can be assigned to the chain end structure, seems to progress due to cross-linking reactions caused by radiation exposure. In the effect on molecular weight distribution by gamma-ray irradiation, though once the cross-linking reactions occurred by the irradiation, the molecular chain scission progressed afterwards, and, as a result, a decline of the molecular weight of LDPE was observed. As for the electron beam irradiation sample, however, the insoluble component (such as gelation) produced by the cross-linking reactions increased and little depolymerization is observed, indicating that the gamma-ray irradiation samples are quite different from the electron beam irradiation ones. (author)

139

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)

140

Study of irradiated toxins 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 {sup 60}Co gamma rays, yielding toxoids with good immunogenicity. The achievement of modified antigens with lower toxicity and preserved or improved immunogenicity can be useful. Ionizing radiation has been proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we have investigated the immunological behavior of bothropstoxin-I, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were investigated 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 the protein (aggregates and oligomers). Our data indicate that irradiated toxins were immunogenic and the antibodies elicited by them were able to recognize the native toxin in ELISA. These results indicate that irradiation of toxic proteins can promote significant modifications in their structures, but still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that the irradiated protein induced higher titers of IgG2a and IgG2b, suggesting that Th1 cells were predominantly involved in the immune response. (author)

Caproni, Priscila; Baptista, Janaina A.; Almeida, Tiago Luiz de; Passos, Luiz A.C.; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: pricaproni@hotmail.com

2007-07-01

 
 
 
 
141

Study of irradiated toxins 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 useful. Ionizing radiation has been proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, little is known about the modifications that irradiated molecules undergo and even less about the immunological response that such antigens elicit. In the present work, we have investigated the immunological behavior of bothropstoxin-I, a K49 phospholipase, before and after irradiation. Structural modifications of the toxin were investigated 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 the protein (aggregates and oligomers). Our data indicate that irradiated toxins were immunogenic and the antibodies elicited by them were able to recognize the native toxin in ELISA. These results indicate that irradiation of toxic proteins can promote significant modifications in their strute significant modifications in their structures, but still retain many of the original antigenic and immunological properties of native proteins. Also, our data indicate that the irradiated protein induced higher titers of IgG2a and IgG2b, suggesting that Th1 cells were predominantly involved in the immune response. (author)

142

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

Directory of Open Access Journals (Sweden)

Full Text Available Ionizing radiation has been successfully employed to modify the immunological properties of biomolecules. Very promising results were obtained when crude animal venoms, as well as isolated toxins, were treated with 60Co gamma rays, yielding toxoids with good immunogenicity. The achievement of 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.

P Caproni

2009-01-01

143

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

144

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.

145

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.)

146

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-01-01

147

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)

148

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

149

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

150

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

International Nuclear Information System (INIS)

Physical factors associated to total body irradiation using 60Co gamma rays beams, were studied in order to develop a calculation method of the dose distribution that could be reproduced in any radiotherapy center with good precision. The method is based on considering total body irradiation as a large and irregular field with heterogeneities. To calculate doses, or doses rates, of each area of interest (head, thorax, thigh, etc.), scattered radiation is determined. It was observed that if dismagnified fields were considered to calculate the scattered radiation, the resulting values could be applied on a projection to the real size to obtain the values for dose rate calculations. In a parallel work it was determined the variation of the dose rate in the air, for the distance of treatment, and for points out of the central axis. This confirm that the use of the inverse square law is not valid. An attenuation curve for a broad beam was also determined in order to allow the use of absorbers. In this work all the adapted formulas for dose rate calculations in several areas of the body are described, as well time/dose templates sheets for total body irradiation. The in vivo dosimetry, proved that either experimental or calculated dose rate values (achieved by the proposed method), did not have significant discrepancies. (author)

151

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)

152

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

153

Corrosion of carbon steel and low-alloy steel in diluted seawater containing hydrazine under gamma-rays irradiation  

International Nuclear Information System (INIS)

Seawater was injected into reactor cores of Units 1, 2, and 3 in the Fukushima Daiichi nuclear power station as an urgent coolant. It is considered that the injected seawater causes corrosion of steels of the reactor pressure vessel and primary containment vessel. To investigate the effects of gamma-rays irradiation on weight loss in carbon steel and low-alloy steel, corrosion tests were performed in diluted seawater at 50°C under gamma-rays irradiation. Specimens were irradiated with dose rates of 4.4 kGy/h and 0.2 kGy/h. To evaluate the effects of hydrazine (N2H4) on the reduction of oxygen and hydrogen peroxide, N2H4 was added to the diluted seawater. In the diluted seawater without N2H4, weight loss in the steels irradiated with 0.2 kGy/h was similar to that in the unirradiated steels, and weight loss in the steels irradiated with 4.4 kGy/h increased to approximate 1.7 times of those in the unirradiated steels. Weight loss in the steels irradiated in the diluted seawater containing N2H4 was similar to that in the diluted seawater without N2H4. When N2 was introduced into the gas phase in the flasks during gamma-rays irradiation, weight loss in the steels decreased. (author)

154

Defects in GaP red light-emitting-diodes introduced by Co-60 gamma ray irradiation  

International Nuclear Information System (INIS)

Degradation of gallium phosphide light-emitting-diodes (LED's) caused by Co-60 gamma ray irradiation has been studied by the deep level transient spectroscopy. Irradiation introduces electron traps located at 0.415 eV below the conduction band and decreases intensity of the red emission. The introduction of these traps is considered to be a cause of the degradation of GaP red LED's. (author)

155

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

International Nuclear Information System (INIS)

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

156

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

International Nuclear Information System (INIS)

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

157

Gene expression profiles in human lymphocytes irradiated in vitro with low doses of gamma rays.  

Science.gov (United States)

The molecular mechanisms underlying responses to low radiation doses are still unknown, especially in normal lymphocytes, despite the evidence suggesting specific changes that may characterize cellular responses. Our purpose was to analyze gene expression profiles by DNA microarrays in human lymphocytes after in vitro irradiation (10, 25 and 50 cGy) with gamma rays. A cytogenetic analysis was also carried out for different radiation doses. G 0 lymphocytes were irradiated and induced to proliferate for 48 h; then RNA samples were collected for gene expression analysis. ANOVA was applied to data obtained in four experiments with four healthy donors, followed by SAM analysis and hierarchical clustering. For 10, 25 and 50 cGy, the numbers of significantly (FDR CREB3L2, DDX49, STK25 and XAB2 were down-regulated. Chromosome damage was significantly induced for doses >or=10 cGy (total aberrations) and >or=50 cGy (dicentrics/ rings). Therefore, low to moderate radiation doses induced qualitative and/or quantitative differences and similarities in transcript profiles, reflecting the type and extent of DNA lesions. The main biological processes associated with modulated genes were metabolism, stress response/DNA repair, cell growth/differentiation, and transcription regulation. The results indicate a potential risk to humans regarding the development of genetic instability and acquired diseases. PMID:18088177

Fachin, Ana L; Mello, Stephano S; Sandrin-Garcia, Paula; Junta, Cristina M; Donadi, Eduardo A; Passos, Geraldo A S; Sakamoto-Hojo, Elza T

2007-12-01

158

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)

159

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.

160

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-01

 
 
 
 
161

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

162

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

International Nuclear Information System (INIS)

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

163

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

CERN Document Server

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

Scaff, L A M

2001-01-01

164

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

International Nuclear Information System (INIS)

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

165

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)

166

Controlled synthesis and morphology-dependent electromagnetic properties of nickel nanostructures by {gamma}-ray irradiation technique  

Energy Technology Data Exchange (ETDEWEB)

We report the morphology-dependent magnetic and electromagnetic absorption properties of various nickel nanostructures prepared by a {gamma}-ray irradiation technique. By changing the applied surfactants during the irradiation, sting-like, agglomerated, and chain-like nickel nanostructures are obtained when using polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and sodium dodecyl benzene sulfonate (SDBS) as the surfactants. It is determined that the excellent electromagnetic absorption ability of sting-like nickel arises from point discharge effect, while chain-like nickel shows the best absorption property due to the geometrical effect. We think that the preparation of nickel nanostructures with various morphologies by this facile {gamma}-ray irradiation technique can be a general route for other metals.

Zhao Hongtao [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Technical Physics Institute of Heilongjiang Academy of Sciences, Harbin 150086 (China); Han Xijiang, E-mail: hanxj63@yahoo.com.c [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhang Lifang [Technical Physics Institute of Heilongjiang Academy of Sciences, Harbin 150086 (China); Wang Gangyi [Harbin Pharmaceutical Group Holding Co. Ltd., Harbin 150086 (China); Wang Chao; Li Xueai [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Xu Ping, E-mail: pxu@hit.edu.c [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

2011-03-15

167

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)

168

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-06-01

169

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)

170

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

Science.gov (United States)

The cell cycle was analyzed using anti-BrdU monoclonal antibody, and changes in cell kinetics after gamma ray irradiation as evaluated by this BrdU-PI double staining were compared with those evaluated by the DNA histogram method based on PI staining. The effect of irradiation on the cell kinetics has been studied according primarily to the number of G2 blocked cells. By the present BrdU method, rapid transition of the G1-S phase was observed within 2 hours of irradiation, and then G1 block was observed. Cells in the S phase progressed to the G2 + M phase, in which they were arrested, resulting in a decrease in the percentage of S cells to 5% or less. After 8 hours, release of G1 block was observed, and G2 + M cells returned to the G1 phase after 18 or more hours. These initial G1 blocked cells induced by irradiation were confirmed for the first time by the present BrdU-PI double staining. By the conventional method based on the DNA histogram, accurate determination of S cell fraction was difficult due to overlapping of the DNA contents of G1 cells and early S cells and those of late S cells and G2 cells. On the other hand, BrdU-PI double staining allowed direct differentiation of G1, S, and G2 + M cells, especially between G1-S and S-G2 + M cells. The analysis of cell kinetics using BrdU is advantageous over the conventional autoradiographic methods in that it allowed more rapid assay with very high sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2477794

Akagi, K; Tanaka, Y

1989-04-25

171

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

Science.gov (United States)

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 D10 value of B. cereus at 4 degrees C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 degrees C. The gamma irradiation of the bacteria without incubation at 4 degrees C before irradiation was more effective than that of the bacteria with incubation overnight at 4 degrees 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 degrees 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. PMID:12638185

Miyahara, Michiko; Miyahara, Makoto

2002-01-01

172

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

173

A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (3)  

International Nuclear Information System (INIS)

This report intends to clarify the relationship between the total exposure dose and scratch resistance to the specimens SF, SH, MF and MH, giving coating treatments to P.M.M.A. (dental polymethylmethacrylate) and exposing to the irradiation of 60Co gamma ray at each dose rate. And based on the results, it is intended to develop coated P.M.M.A. with excellent scratch resistance give by irradiation of radioactive ray. From this study, the following results have been obtained. Irradiation of 60Co gamma ray would give the best results at the exposure at 1 x 106 R. The SF and SH specimens in wet condition exposed to 60Co gamma ray irradiation at 1 x 106 R showed a quantity of abrasion of only 17% that of untreated P.M.M.A. and the barrel test revealed outstanding abrasion and scratch resistance. Abrasion and scratch resistance of coated specimens are better utilized in wet conditions performing three times better than those in dry conditions. (author)

174

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

175

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

176

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

177

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.)

178

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

179

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)

180

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)

 
 
 
 
181

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

Energy Technology Data Exchange (ETDEWEB)

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 {sup 60}Co (3.7 GBq) and {sup 137}Cs (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)

Yamaguchi, Yoshiaki; Yamashita, Jinpei; Yamamoto, Takayoshi [Osaka Univ., Suita (Japan). Radioisotope Research Center; Yamamoto, Junji; Nomura, Taisei

1996-09-01

182

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

International Nuclear Information System (INIS)

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

183

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

Directory of Open Access Journals (Sweden)

Full Text Available 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

2005-09-01

184

Energy deposition and fragments production resulting from gamma-ray or ion beam irradiation of an ion exchange resin  

Science.gov (United States)

The extraction efficiency of ion exchange resins aimed at the reprocessing of nuclear effluents is strongly dependent on gamma-ray induced modifications of their chemical structure. A poly(4-vinylpyridine) resin, or P4VP, has been subjected to gamma irradiation using a 137Cs source (E[gamma] = 662 keV) and we have attempted to characterize its structural modifications using TOF-SIMS techniques based on low (keV) and high (MeV) primary ion beam energies. These analytical techniques are based on the formation of fragments resulting respectively from atomic and electronic collisions of heavy ions. As a result, the differences in nature and relative intensity of the emitted secondary ions, as well as the variation of their intensity as a function of the absorbed dose of gamma rays (up to 14 400 kGy), can be interpreted from different types of bond breaking. While gamma-ray absorption results in benzylic or pyridinic scissions, MeV ion bombardment may induce simultaneous (and close) pyridinic-pyridinic or pyridinic-benzylic scissions, or both. Accordingly, the technique is very sensitive to the presence of fragments preformed under gamma irradiation. This is not observed with keV bombardment which may destroy the pyridine nucleus. The SIMS analysis of the soluble fraction of the irradiated material (free radicals and fragments) and of the remaining material confirms the proposed fragmentation paths leading to positive and negative ion emission. Such results fully support the important finding that these gamma-ray induced modifications are only observed from negative emission under MeV ion bombardment.

Nsouli, B.; Draye, M.; Allali, H.; Lemaire, M.; Thomas, J.-P.

1996-07-01

185

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)

186

In situ synthesis and characterization of lead sulfide nanocrystallites in the modified hyperbranched polyester by gamma-ray irradiation  

International Nuclear Information System (INIS)

Lead sulfide (PbS) nanocrystallites in the modified hyperbranched polyester matrix were prepared in situ by 60Co gamma-ray irradiation with sodium thiosulfate at room temperature, and characterized with Fourier transform infrared, X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL). The average diameter of PbS nanocrystallites was estimated to be 7.8 nm on the basis of analysis of the TEM image and dispersed homogeneously within the modified hyperbranched polyester matrix. The possible formation mechanism of the PbS nanocrystallites under irradiation was discussed

187

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)

188

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)

189

Back and side scatter radiation from 60Co gamma ray irradiation  

International Nuclear Information System (INIS)

It is generally recommended that the ionization chamber must be calibrated in air using 60Co gamma ray beams. In an ionization chamber having cylindrical shape, the ionization cavity may be surrounded by an adequate thickness of build-up cap for any direction. For some ionization chambers having parallel plate shape, however, the cavity is surrounded by an extra scattering material for back and side directions. The extra scattering as a function of back and side extra volume have been measured for 60Co gamma ray beams. The correction factor for the extra scatter effect was given by an approximate equation with good accuracy. (author)

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

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)

192

[Accurate measurement of doses in the sample chamber of a 137Cs gamma-ray irradiation apparatus].  

Science.gov (United States)

Dose rates in the sample chamber of a 137Cs gamma-ray irradiation apparatus (Nordion International Inc., Gammacell 40 Exactor) were accurately measured using an ionization chamber dosimeter. The dose rates obtained were 5.2-7.2% higher at the upper and lower planes than at the middle plane in the sample chamber. In the process of starting and stopping the irradiation, the additional dose during the movement of the source (end effects) was evaluated to be 0.85-1.21% (average 1.05 +/- 0.05%) of that estimated from the steady dose rate for 1 min. When the irradiation period was less than 1 min, it was necessary to make a correction for the end effects in order to keep the error in irradiation dose below 1%. PMID:10629903

Abe, T; Yamamoto, H; Norimura, T

1999-12-01

193

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

194

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

International Nuclear Information System (INIS)

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

195

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)

196

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)

197

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-04-01

198

About the radiation stability of electrophysical properties in compensated silicon under gamma-rays sup 6 sup 0 Co irradiation  

CERN Document Server

The change in the concentration of the charge carriers in a compensated silicon under the gamma-ray irradiation is investigated. It has been found that than carrier removal rate in the compensated silicon is lower than that of control samples. A new mechanism resulting in the radiation stability of electrophysical properties of the compensated silicon is discussed. The decreasing of the charge carrier removal rate under the exposure of gamma-quanta can be explained by the radiation amplification of fluctuation barriers between low- and high-ohmic ranges and the intensification of the departure of the part of generating defects to drains in the compensated silicon with deep levels

Yunusov, M S; Dzhalelov, M A

2001-01-01

199

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)

200

Pulsed EPR study of low-dose irradiation effects in L-alanine crystals irradiated with {gamma}-rays, Ne and Si ion beams  

Energy Technology Data Exchange (ETDEWEB)

Low-dose irradiation effects in L-alanine single crystals irradiated with {gamma}-rays, Ne and Si ion beams have been investigated by means of a two-pulse electron spin echo (ESE) technique. An effective phase memory time, T{sub M}, was measured from the first stable L-alanine radical, SAR1, and its complex relaxation mechanism is discussed. Both spectral and instantaneous diffusion contributions to the total effective relaxation rate have been extrapolated through the detection of the two-pulse ESE signal as a function of turning angle. The local microscopic concentration of paramagnetic centers C(ions)/C({gamma}-ray) for low-dose heavy-ion irradiation has been deduced from the corresponding spin-spin interaction.

Rakvin, B. [Ruder Boskovic Institute, P.O. Box 180, 10002 Zagreb (Croatia)], E-mail: rakvin@irb.hr; Maltar-Strmecki, N. [Faculty of Veterinary Medicine, University of Zagreb, P.O. Box 466, 10002 Zagreb (Croatia); Nakagawa, K. [RI Research Center, Fukushima Medical University, 1 Hikarigaoka, Fukushima 960-1295 (Japan)

2007-10-15

 
 
 
 
201

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

202

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

Science.gov (United States)

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. 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. Postirradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

Schwarze, G. E.; Frasca, A. J.

1991-01-01

203

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.

204

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

International Nuclear Information System (INIS)

.5 and 3.17 for induction of liver tumors, pituitary tumors, ovarian tumors and lung tumors, respectively. This result implies that mice of the neonatal period are highly susceptible to induction of these tumors. On the other hand, shape of dose-response curve for incidence of bone tumors was concave upward. Dose-response relationship for induction of bone tumors was fitted by a model that tumorigenic activity of gamma rays is proportional to square of dose. (author)

205

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)

206

Thermal, tensile and rheological properties of linear low density polyethylene (LLDPE) irradiated by gamma-ray in different atmospheres  

International Nuclear Information System (INIS)

The aim of this paper is to investigate structural changes of linear low density polyethylene (LLDPE) 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 LLDPE, after gamma irradiations were evaluated using thermogravimetric analyzer (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

207

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., Leitão.

2005-09-01

208

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

Science.gov (United States)

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.

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

2014-05-01

209

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; Lugão, A. B., E-mail: dfparra@ipen.br, E-mail: ablugao@ipen.br [Center of Chemistry and Environment, Institute of Energy and Nuclear Research - IPEN (Brazil); Gaia, R., E-mail: renan-gaia7@hotmail.com [Faculdades Oswaldo Cruz (Brazil)

2014-05-15

210

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

211

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)

212

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

International Nuclear Information System (INIS)

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

213

Chemiluminescence and chemorheology of ?-ray irradiated ethylene-propylene elastomer  

International Nuclear Information System (INIS)

Ethylene-Propylene elastomer (EPDM) was irradiated by Co-60 ? ray at room temperature. Chemiluminescence (CL) from irradiated elastomer was measured and equation (1) was obtained. CL sub(r) = CL0+C sub(s)D sup(?) exp(-E/RT) (1) (where CL sub(r) is counts of CL from irradiated EPDM, CL0 is that of non-irradiated EPDM, C sub(s) is the constant which depends on the kind of the material, D is dose, ? is dose exponents, E is activation energy and T is the temperature (0K) at which CL is measured). Chemical stress relaxation of irradiated EPDM was also measured and equation (2) was obtained. K sub(r) = K0+C sub(s)D sup(?) exp(-E/RT) (2) (where K sub(r) is the rate of chemical stress relaxation of irradiated EPDM, K0 is that of non irradiated EPDM, T is the temperature (0K) at which chemical stress relaxation is measured and other captions are the same as equation (1)). Both in equation (1) and (2), ? was found to be 2.0. E is 83.6 kj/mol in equation (1) and E is 50.2 kj/mol in equation (2). (author)

214

Mutant frequencies in lacZ transgenic mice following the internal irradiation from {sup 89}Sr or the external {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Mutagenesis assays using transgenic mice have been recently developed and applied to the studies on the mutagenesis. The present study was undertaken to clarify whether the mutagenesis assay with transgenic mice could detect the mutations induced by the internal {beta}-ray irradiation from {sup 89}Sr or the external {gamma}-ray irradiation. The transgenic mice used were Muta{sup TM} mouse strain, which carries 80 copies of the bacterial lacZ gene per cell as a target of mutagenesis. Female animals were given intraperitoneal injections of ethylnitrosourea (50 mg/kg per day) for five days, a single intravenous injection of {sup 89}Sr (7.4 and 74 MBq/kg), or daily irradiation with 1.5 Gy {gamma}-rays for five days. The liver, spleen, and bone marrow were collected 15 days after the treatment with each agent. After the genomic DNA was extracted from each tissue, mutation analysis at lacZ locus was carried out. The spontaneous lacZ mutant frequencies were 2-4 x 10{sup -5}. The frequencies of mutants induced by ethylnitrosourea in the liver, spleen and bone marrow were 68, 55, and 11 x 10{sup -5}, respectively. In contrast, the mutant frequencies detected after the treatment with {gamma}-rays were not so high in all three tissues as those treated with ethylnitrosourea. The injection of {sup 89}Sr at a dose of 74 MBq/kg induced mutation at significantly higher frequencies in the bone marrow, but not in the liver and spleen. The results clearly showed that the mutation assay system used here could detect mutagenic effects of the local irradiation from {sup 89}Sr, but was relatively insensitive to the {beta}- and {gamma}-ray irradiation compared with the chemical mutagens such as ethylnitrosourea. (author)

Takahashi, Sentaro; Kubota, Yoshihisa; Sato, Hiroshi [National Inst. of Radiological Sciences, Chiba (Japan)

1998-03-01

215

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

International Nuclear Information System (INIS)

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

216

Supermolecular structural organization of isotactic polypropylene irradiated by different gamma ray doses  

International Nuclear Information System (INIS)

The effect of gamma radiation (up to 200 Mrad) on the super-molecular structure of isotactic polypropylene is studied. The radiation is found to affect weakly the crystallite structure. The crystallite surfaces and the amorphous regions are the only ones supposed to be affected. At the same time the melting temperature decreases considerably even with low gamma ray doses. The possible reasons for the neglible variation of the crystal structure, on the one hand, and the substantial drop in the melting temperature (by more than 30oC), on the other hand, are discussed. 8 figs., 24 refs

217

Development of High Yielding Mutants of Brassica campestris L. cv. Toria Selection Through Gamma Rays Irradiation  

Directory of Open Access Journals (Sweden)

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

Muhammad Aslam Javed

2003-01-01

218

Correlation between release of deuterium and annihilation of irradiation defects produced by gamma-ray in Li2TiO3  

International Nuclear Information System (INIS)

The dependence of irradiation defect density on hydrogen isotope release behaviors in Li2TiO3 was studied. Li2TiO3 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?-center and O2?-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

219

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

220

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

 
 
 
 
221

Analysis of interface states and series resistance at MIS structure irradiated under {sup 60}Co {gamma}-rays  

Energy Technology Data Exchange (ETDEWEB)

In this research, we investigated the effect of {sup 60}Co {gamma}-ray exposure on the electrical properties of Au/SnO{sub 2}/n-Si (MIS) structures using current-voltage (I-V) measurements. The fabricated devices were exposed to {gamma}-ray doses ranging from 0 to 300 kGy at a dose rate of 2.12 kGy h{sup -1} in water at room temperature. The density of interface states N{sub ss} as a function of E{sub c}-E{sub ss} is deduced from the forward bias I-V data for each dose by taking into account the bias dependence effective barrier height and series resistance of device at room temperature. Experimental results show that the {gamma}-irradiation gives rise to an increase in the zero bias barrier height {phi}{sub BO}, as the ideality factor n and N{sub ss} decrease with increasing radiation dose. In addition, the values of series resistance were determined using Cheung's method. The R{sub s} increases with increasing radiation dose. The results show that the main effect of the radiation is the generation of interface states with energy level within the forbidden band gap at the insulator/semiconductor interface.

Tataroglu, A. [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)], E-mail: ademt@gazi.edu.tr; Altindal, S. [Department of Physics, Faculty of Arts and Sciences, Gazi University, 06500 Ankara (Turkey)

2007-10-11

222

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

223

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

International Nuclear Information System (INIS)

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

224

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-09-01

225

Study of Radiation Effects on Upland Cotton (Gossypium hirsutum L. Pollen Grain Irradiated by 60Co-gamma Ray  

Directory of Open Access Journals (Sweden)

Full Text Available This paper studied the effects of 60Co-gamma ray on the pollen grains of upland cotton. The irradiation effects on pollen grains were tested in terms of the ultrastructural changes in the exine and interior of pollen grains, their germination rate, the single primer amplification reaction polymorphism of ovule developed after the pistils were pollinated by the pollen grains which had been irradiated with 60Co-gamma ray, and the law of genetic variation of their M1, M2 progeny. The results showed that 60Co-gamma ray had no effects on the exine wall of the pollen grains. The interior structure of pollen grain were destroyed significiantly. The interior wall became thin and irregular, and part of it concavitied to the inner. The endoplasmic reticulum depolymerized. The amount and the density of pollen grain inclusions increased. The number of pollen tubes in style decreased by 38%, compared with the control group (natural pollen grain. The single primer amplification reaction polymorphism of ovule increased. The germination percentage of M1 progeny was decreased by 41.03%. And with the cotton plants of M1 progeny, the length of taproot, longest lateral root, average lateral root, the number of lateral root, and the height of seedling decreased by 22.24%, 18.93%, 11.80%, 28.02%, 23.05%, respectively, compared with the control group. The percentage of sterility plants was 56.7%. The coefficients of variations of boll number, lint percentage, perimeter of stem, seed index, fruit branch number, longissimus fruit branch and plant height increased by 103.206%, 74.588%, 75.96%, 69.83%, 33.25% and 29.624%, 11.843%, respectively., compared with the control group. With the cotton plants of M2 progeny, the percentage of sterility plants was 56.7%. And the coefficients of variations of boll number, seed cotton yield, fruit branch number, plant height, boll height, and lint percentage increased by 21.944%, 16.261%, 3.827%, 3.986%, 7.25% and 0.497%, respectively., compared with the control group. The coefficients of variations and change range of agronomic traits in M2 progeny were less than them in M1 progeny.

Jieyu Yue

2012-05-01

226

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)

227

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

228

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

229

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)

230

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

International Nuclear Information System (INIS)

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

231

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

Science.gov (United States)

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.

Wen, J. X.; Luo, W. Y.; Xiao, Z. Y.; Wang, T. Y.; Chen, Z. Y.; Zeng, X. L.

2010-02-01

232

Transferases activity in blood plasma of chickens hatched from eggs irradiated during incubation by low dose gamma rays  

International Nuclear Information System (INIS)

In our earlier studies chickens hatched from eggs irradiated with 0.15 Gy gamma rays before incubation showed a significantly higher growth than controls during the fattening period (1-42 days). The activity of aspartate-aminotransferase (AST), alanine-aminotransferase (ALT) and plasma glucose in the same chickens were also significantly higher. These results suggested that low-dose gamma-radiation stimulated certain metabolic processes in chickens hatched from eggs irradiated before incubation. The goal of this study was to determine the effects of low-dose ionising radiation on AST and ALT activity in the blood plasma of chickens hatched from eggs irradiated during incubation. The eggs of heavy breeding chickens (Avian, line 34) were exposed to 0.15 Gy of gamma-radiation (60Co) on the seventh day of incubation, i.e. at the time when the organogenesis in chickens is completed. The control group of chickens hatched from non-irradiated eggs. All other conditions were the same for both groups. After hatching, blood samples were taken from the wing vein on days 1, 3, 5, 7, 10, 20, 32 and 42. The activity of both enzymes was determined spectrophotometrically using Boehringer Mannheim GmbH optimised kits. On day 10, AST and ALT activity were significantly higher in the blood plasma of chickens hatched from irradiated eggs, but it significantly dropped for both enzymes on day 20. Our results indicate that exposure of eggs to low-dose gamma-radiation on the seventh day of incubation affects AST and ALT activity in the blood plasma of chickens hatched from irradiated eggs. However, this effect is somewhat different from the effects of egg exposure to low-dose gamma radiation before incubation.(author)

233

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

International Nuclear Information System (INIS)

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

234

Study on stability of components and antioxidative activity of a {gamma}-ray irradiated herb  

Energy Technology Data Exchange (ETDEWEB)

This study was performed to investigate the stability of components and antioxidative activities of a gamma irradiated herb, Astragalus Membranaceus Bunge (AMB). The chemical components of gamma-irradiated and non-irradiated AMB were analyzed by HPLC, and their antioxidative activities were also evaluated in scavenging of DPPH radical and inhibition of lipid peroxidation. For HPLC analysis, calycosin, a major component, was isolated as a standard material, and EtOAc fractions were prepared from irradiated (10 kGy) and non-irradiated AMB. HPLC profile of the two EtOAc fractions showed almost same pattern. One major peak was detected during retention times (tR) at 15.07 min in irradiated sample, and at 15.09 min in non-irradiated sample, compared with calycosin (15.11 min). In the experiment of antioxidative effects, gamma-irradiated and non-irradiated samples also showed the same level of EDA value and lipid peroxidation inhibitory activity. These results suggest that chemical components and biological activities of AMB were not affected by gamma irradiation.

Jung, I. Y.; Lee, J. S.; Jung, W. H.; Byun, M. W.; Cho, S. K. [KAERI, Taejon (Korea, Republic of)

2003-07-01

235

Immunological properties of 60Co gamma-rays irradiated bothropstoxin-I  

International Nuclear Information System (INIS)

We investigated the immunological behavior of BTHX-1, before and after irradiation. SDS-PAGE showed that BTHX-1 irradiated in the presence of NaNO3, had its structure preserved. Animals' plasma immunized with native BTHX-1 had high IgG1 titers. The irradiated protein induced high titers of IgG2b. When the toxin was irradiated with t-butanol, there was a slight decrease in the production of IgG2b. Real-time PCR showed that both the IL-2 as for IL4 was more expression from the cells of the animals immunized with BTHX-1 irradiated. These results indicate that irradiation of proteins leads to significant structural modifications. (author)

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

DNA-repair after irradiation of cells with gamma-rays and neutrons  

International Nuclear Information System (INIS)

The structural alterations of calf thymus DNA produced by neutron or gamma irradiation were observed by absorption spectra, sedimentation rate and viscosity measurements. Mixed neutron-gamma irradiation produced fewer single and double strand breaks compared with pure gamma irradiation. RBE-values for mixed neutron-gamma radiation were less than 1, and DNA damage decreased with increasing neutron dose rate. Repair processes of DNA occuring after irradiation were measured in mouse spleen suspensions and human lymphocytes using autoradiographic methods and gradient centrifugations. The number of labelled cells was smaller after mixed neutron-gamma irradiation than after gamma irradiation. The rejoining of strand breaks in alkaline and neutral sucrose was more efficient after gamma irradiation than after mixed neutron-gamma irradiation. Finally, the effect of detergents Tween 80 and Nonident P40 on unscheduled DNA synthesis was studied by autoradiography after mixed neutron-gamma irradiation (Dn=5 krad). The results showed that the DNA synthesis was inhibited by detergent solutions of 0.002%

238

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

Energy Technology Data Exchange (ETDEWEB)

The gamma-ray activity from short-lived fission products has been measured in fresh and burnt UO{sub 2} fuel samples after irradiation in a zero-power reactor. For the first time, short-lived gamma-ray activity from fresh and burnt fuel has been compared and fresh-to-burnt fuel fission rate ratios have been derived. For the measurements, well characterized fresh and burnt fuel samples, with burn-ups up to 46 GWd/t, were irradiated in the zero-power research reactor PROTEUS. Fission rate ratios were derived based on the counting of high-energy gamma-rays above 2200 keV, in order to discriminate against the high intrinsic activity of the burnt fuel. This paper presents the measured fresh-to-burnt fuel fission rate ratios based on the {sup 142}La (2542 keV), {sup 89}Rb (2570 keV), {sup 138}Cs (2640 keV) and {sup 95}Y (3576 keV) high-energy gamma-ray lines. Comparisons are made with the results of Monte Carlo modeling of the experimental configuration, carried out using the MCNPX code. The measured fission rate ratios have 1? uncertainties of 1.7–3.4%. The comparisons with calculated predictions show an agreement within 1–3?, although there appears to be a slight bias (?3%).

Kröhnert, H., E-mail: hanna.kroehnert@ensi.ch [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Perret, G.; Murphy, M.F. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); Chawla, R. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland); École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2013-01-11

239

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

International Nuclear Information System (INIS)

rose. There is close positive correlation between chromosome number and biomass of each mutant line. The chromosome number estimation is a proper indicator to monitor damage of adopted irradiation methods. Possible reason why the chronic culture methods indicate higher frequency and wider spectrum on mutation is demonstrated. . Problems solved and prospect of chronic irradiation and in vitro techniques are discussed. (Author)

240

Immune response against bothropstoxin-I irradiated with 60Co gamma rays  

International Nuclear Information System (INIS)

its native counterpart. Irradiated toxins were immunogenic and the antibodies elicited by them were able to recognize the native toxin in ELISA. These results indicate that irradiation of toxic proteins can promote significant modifications in their structures, but still retain many of the original immunological properties. (author)

 
 
 
 
241

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

International Nuclear Information System (INIS)

We have investigated temporal behavior of the photoluminescence (PL) spectra of thin films containing CdSe/ZnS quantum dots irradiated by 532 nm laser radiation and gamma-rays. Under ?100 W/cm2 laser radiation, the PL intensity (IPL) increases with irradiation time upto about 500 s and thereafter declines linearly. The wavelength of the PL emission (?peak) exhibits a blue-shift with exposure time. Upon simultaneous irradiation by 100 W/cm2 532-nm laser, as well as 0.57 and 1.06 MeV gamma-rays, the temporal behaviors of both IPL and ?peak are significantly different; IPL increases to a saturation level, and the magnitude of the blue-shift in ?peak is reduced. We discuss possible mechanisms underlying these results

242

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

International Nuclear Information System (INIS)

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

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

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

Directory of Open Access Journals (Sweden)

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

245

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

International Nuclear Information System (INIS)

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

246

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

Science.gov (United States)

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

Kleut, D. N.; Markovi?, Z. M.; Holclajtner Antunovi?, I. D.; Drami?anin, M. D.; Kepi?, D. P.; Todorovi? Markovi?, B. M.

2014-09-01

247

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)

248

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.)

249

Chromosome aberrations in cells of rat bone marrow after fractionated irradiation with various gamma ray doses  

International Nuclear Information System (INIS)

Sexually mature male Wistar has been gamma-irradiated 5 days of the week with a single dose of 3.874 mC/kg b.w. (dose rate 0.645 mA/kg, 137Cs). Samples for cytogenetic investigations of bone-marrow cells have been prepared 18 hrs after the last irradiation when doses of 0.0155, 0.0271, 0.0503, 0.0774 and 0.1045 C/kg have been reached. Spontaneous structure aberrations are presented by acentric single and pair fragments. Chromatid and chromosomal fragments, as well as translocations have been also found after the irradiation. The percentage of the cells with aberrations increases from 2.5% for non-irradiated controls to 15.8% for those irradiated with the highest cummulative dose. The radiation-induced chromosome injury increases improportionally to the dose cummulated. The fractionation of the dose reduces the cytogenetic effect by 2-4 times in comparison with the chromosomal aberration yield after single acute irradiation (data from an earlier authors' study). The efficiency decrease is discussed in terms of elimination or reparation of induced injuries, death of the cells with aberrations and increasing adaptation to low dose radiation. 1 tab., 6 refs

250

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-07-01

251

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)

252

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-05-01

253

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

International Nuclear Information System (INIS)

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

254

Radiation resistance of elastomers; Vieillissement des elastomeres sous irradiation  

Energy Technology Data Exchange (ETDEWEB)

The COMOR group is a network of laboratories from both the CEA and the CNRS. This network is particularly involved in fundamental and applied studies on the ageing of polymers under irradiation. COMOR has studied the ageing of EPDM (ethylene-propylene-diene-monomer) because this elastomer is often used in nuclear environment (in cable coating for instance). In this study, we have prepared materials with different formulations and we have characterised their use-condition properties (dielectric and mechanical) before and after {gamma} irradiation. The dielectric measurements are well adapted to study the oxidation and the crosslinking phenomena which appear during the irradiation ageing. We have shown that after a short time, the oxidation is limited by the diffusion of oxygen. A phenolic antioxidant is not able to protect the polymer against the oxidation. However, we used a concentration typical of a purely thermal stabilisation case (0,1%). On the other hand, a diamine type additive with a concentration of 1% showed efficient stabilisation. The mechanical properties of the regular EPDM are strongly affected by the irradiation but there is little difference with regard to radiation resistance between both types of raw materials. Nevertheless, the NORDEL IP 3725 stabilised with the amine has better initial mechanical properties whereas the NORDEL 2722 offers higher strength above 300 kGy. Our results emphasize the stake of a proper stabilisation of polymers with respect to ionising radiation. (authors)

Hourquebie, P.; Bigarre, J.; Forveille, J.L.; Raby, J. [CEA Centre d' Etudes du Ripault, Laboratoire Materiaux Organiques et Dielectriques, DMAT/SCMF/LOD, 37 - Tours (France); Lazare, L. [CEA Centre d' Etudes du Ripault, Lab. de Physico-Chimie, DXPL/SMEP/LPC, 37 - Tours (France)

2002-07-01

255

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)

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

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)

258

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

259

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

International Nuclear Information System (INIS)

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

260

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

International Nuclear Information System (INIS)

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

 
 
 
 
261

Growth evaluation of avocado selections irradiated with gamma rays Co 60  

International Nuclear Information System (INIS)

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

262

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)

263

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

International Nuclear Information System (INIS)

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

264

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 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)

265

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

266

Investigation of some physical properties of polypropylene irradiated by gamma rays  

International Nuclear Information System (INIS)

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

267

Application of EGS4 for evaluation of material damage due to gamma-ray irradiation  

International Nuclear Information System (INIS)

An EGS4 user code named UCDPA was developed for the simulation of material damages by the electrons and photons considering electromagnetic cascade. The calculated depth distributions of dpa in iron slab were compared to the measurements of material hardening due to 2 and 2.5 MeV electron beam irradiations. The calculated dpa distributions and the measured hardening distributions were in a similar shape which have a peak at about 0.2 mm from irradiated surface. The depth distributions of dpa were also calculated for photons from 0.7 to 10 MeV. (author)

268

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)  

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. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10 ?C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.

Clark, E.

2013-09-13

269

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)

270

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-12-31

271

Influence of gamma ray irradiation on the chemical components and cells of tea leaves  

International Nuclear Information System (INIS)

mature leaves and of chlorophyll b in the new leaves tended to be higher than those of the controls. The radiation increased the concentration of both chlorophylls a and b in the new and mature leaves of Yamakai. The leaves of both varieties after the irradiation showed smooth surfaces. (Kaihara, S.)

272

Hydroxylethylation of baicalin by {gamma}-ray irradiation of baicalin in ethanol  

Energy Technology Data Exchange (ETDEWEB)

Via {gamma}-irradiation of baicalin in ethanol, hydroxylethyl groups were introduced into B and C rings of baicalin. Eight hydroxylethylation products were separated by reverse HPLC and their molecular structures were postulated through their UV, IR, MS and fluorescence spectra. The primary binding constants of baicalin and its hydroxylethylation products in HSA were obtained by the fluorescence method. (author).

Cai Zhongli; He Yongke; Wu Jilan [Beijing Univ., BJ (China). Dept. of Technical Physics

1996-02-01

273

Hydroxylethylation of baicalin by {gamma}-ray irradiation of baicalin in ethanol  

Energy Technology Data Exchange (ETDEWEB)

Via {gamma}-irradiation of baicalin in ethanol, hydroxylethyl groups were introduced into B and C ring of baicalin. Eight hydroxylethylation products were isolated by reverse HPLC and their molecular structures were postulated through their UV, IR, MS and fluorescence spectra. The primary binding constants of baicalin and its hydroxylethylation products in HSA were got by the fluorescence method. (author).

Cai Zhongli; He Yongke; Wu Jilan [Beijing Univ., BJ (China). Dept. of Technical Physics

1995-03-01

274

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

275

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

Energy Technology Data Exchange (ETDEWEB)

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

el-Mofty, M.M.; Sakr, S.A.; Younis, M.W. (Alexandria Univ. (Egypt))

1989-11-01

276

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

International Nuclear Information System (INIS)

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

277

Modification of zinc sulfide phosphors by irradiation with gamma-ray photons and electrons  

International Nuclear Information System (INIS)

The effect of ?-ray photons and electron beams on electroluminescence of the ZnS:(Cu, Br) and ZnS:(Cu, Al, Br) phosphors is studied. Irradiation of both samples with ?-ray photons and of the ZnS(Cu, Br) sample with electrons makes it possible to increase the emission intensity by 20-35% at the optimal radiation dose of 5-10 Mrad. In this case, the relative intensity of the green-emission band increases in the electroluminescence spectra of all samples, presumably due to dissociation of the CuI-CuZn and BrZn-VZn donor-acceptor pairs. Thus, irradiation makes it possible to control the intensity and spectrum of phosphors' emission, which can be used for nonchemical lithography of luminescent layers

278

Response of two sesame cultivars to seed irradiation with gamma rays  

International Nuclear Information System (INIS)

Due to a high degree of variation in the radiosensitivity of sesame (Sesamum, indicum L.), two recommended cultivars with different morphological characteristics were studied in detail for sensitivity to seed irradiation. The experiment was conducted in four replicates with the MI2 and MI3 cultivars. When growth reduction, plant survival and germination were considered as criteria of radiosensitivity, MI3 was more tolerant to irradiation than MI2. Fifty per cent reduction of different growth parameters was achieved with 500 - 700 Gy in MI2 and 750 - 1250 Gy in MI3. Lower doses may be more useful in mutation breeding experiments. It is clear that the radiosensitivity of a cultivar has to be estimated before mutation breeding studies. (author)

279

An electron paramagnetic resonance study of PP and PP/SBS blends irradiated with gamma rays  

International Nuclear Information System (INIS)

Electron paramagnetic resonance (EPR) measurements of Polypropylene (PP) and its blends with a Styrene-Butadiene-Styrene (SBS) copolymer in 10, 20, 30 and 40 wt.% of SBS were carried out. The samples were irradiated in the 0?D?100 kGy range at a dose rate of 4.8 kGy/h. Typical spectra indicative of the formation of peroxy and alkyl radicals were obtained. The dynamics of formation and recombination of radicals in these samples could be explained using a mixed zero and first order generation-recombination fit of the total spin concentration as a function of the integral dose. The time dependence of the spin concentration was studied assuming a mixed first order fit in the decay process. The parameters obtained from the fitting are interpreted in terms of the rate of formation of free radicals at the irradiation time and in terms of the decay time of the total free radical concentration

280

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

International Nuclear Information System (INIS)

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

 
 
 
 
281

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-03-01

282

Changes in melatonin in epiphysis after whole-body irradiation of rats with gamma rays  

International Nuclear Information System (INIS)

Male Wistar rats were exposed to a whole-body gamma dose of 14.4 or 9.6 Gy in darkness. Other groups were exposed to fractionated irradiation with 2.4 Gy twice a week up to 9.6 and 14.4 Gy. At 30 and 60 min after acute lethal irradiation, a decrease in the melatonin (Mel) concentration in the epiphysis was observed; the activity of N-acetyltransferase (NAT) did not differ from that in the control group. Later, signs of increased synthesis of Mel were observed. NAT activity and Mel concentration in the serum increased on day 3 following exposure to 14.4 Gy. Concentration of Mel in epiphysis and serum increased 5 days after exposure to 9.6 Gy. Fractionated irradiation up to 9.6 Gy brought about a decrease in NAT activity 6 h after exposure, without changes in Mel in epiphysis. In rats with an accumulated dose of 14.4 Gy, NAT activity and Mel concentration in epiphysis (serum) decreased 6 h and 3 days, respectively, after exposure, and monoaminooxidase (MAO) increased appreciably on day 3. On day 5, the enzyme activities and Mel concentrations did not differ from those in the control group. Fractionated irradiation up to 14.4 Gy brought about temporary decrease in the synthesis of Mel in epiphysis, which may be due to preferential oxidative deamination of serotonin as compared to its N-acetylation leading to the synthesis of melatonin. The temporary decrease in the Mel concentration in epiphysis in 60 min after single-dose exposure to 14.4 or 9.6 Gy may be a result of similar metabolic changes. The increased synthesis of Mel in epiphysis at a later stage following acute lethal exposure is seen as an adaptive effort of the organism to produce a sufficient amount of hormone with an antioxidative, antistress and immunomodulative effect

283

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)

284

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)

285

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

International Nuclear Information System (INIS)

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

286

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

International Nuclear Information System (INIS)

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

287

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)

288

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.)

289

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

International Nuclear Information System (INIS)

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

290

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

291

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

292

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

International Nuclear Information System (INIS)

The 70SnF2·30P2O5 glasses containing 25-500 ppm of fluorescein exhibit change in color from light yellow to reddish orange (absorption maximum, ?=500 nm) when heated at 240degC for 120-180 min. The fluorophosphate glasses also change the color from light yellow to reddish brown (?=480 nm) when irradiated with 60Co ?-rays of 5x104 Gy. The P-F stretching mode observed in the Fourier transformed infrared (FT-IR) spectra showed an increase in peak intensity along with the coloration, suggesting a cleavage of the weak chemical bond between fluoride ions (F-) and fluorescein molecules. The coloration is ascribed to change of the molecular structure of fluorescein from non-crystalline to crystalline type. ESR spectra of ?-ray irradiated 70SnF2·30P2O5 glasses showed a poorly resolved doublet, which was ascribed to a hole-trapped PO3F- center produced by electron scattering: PO3F2- ? PO3F- + e-. (author)

293

Transmission and mechanical characteristics of an image fiber under gamma-ray irradiation at high temperature  

International Nuclear Information System (INIS)

In the nuclear industries, a visual inspection is required to confirm the integrity of the facilities and components. Recently, a silica-based image fiber has been used for visual inspection in the nuclear facilities. As the emphasis on visual inspection increases, an image fiber which can function in harsh environments, such as under high dose rate, narrow spaces and high temperature is required. It is thus necessary to study the transmission and mechanical characteristics of a silica-based image fiber exposed to ?-ray irradiation and elevated temperatures. We investigated the transmission loss characteristic and mechanical strength under ?-ray irradiation at high temperature with the objective of identifying the causes of deterioration of the image fiber. The induced loss of the transmission in the visible wavelength region was caused by E' center and NBOHC (non-bridging oxygen hole center), and their annealing effect by thermal energy was confirmed. We believe that a high radiation resistant image fiber can be realized by improving its manufacturing condition, since it was identified that there was close relation between the induced loss of transmission and the thermal history of the glass material during melt-fused process of image fiber manufacturing. The mechanical characteristics were also investigated. The mechanical strength decreased by the deterioration of the primary coating. A secondary coating resistant to heat and radiation contributes to maintaining mechanical strength of the image fiber. (author)

294

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)

295

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

International Nuclear Information System (INIS)

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

296

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.

297

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

298

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

299

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)

300

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.)

 
 
 
 
301

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)

302

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.)

303

Gamma rays from hidden millisecond pulsars  

Science.gov (United States)

The properties were studied of a new class of gamma ray sources consisting of millisecond pulsars totally or partially surrounded by evaporating material from irradiated companion stars. Hidden millisecond pulsars offer a unique possibility to study gamma ray, optical and radio emission from vaporizing binaries. The relevance of this class of binaries for GRO observations and interpretation of COS-B data is emphasized.

Tavani, Marco

1992-01-01

304

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.)

305

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

306

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

Energy Technology Data Exchange (ETDEWEB)

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

Green, Lora M

2006-05-25

307

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 kGy·h-1 (?2 Gy·s-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 kGy·h-1) as a result of using a calibration made at a considerably higher dose rate (e.g. 31 kGy·h-1), even when the temperature of irradiation and storage is controlled at 22 deg. C. (author). 14 refs, 13 figs

308

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)

309

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 220°C 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

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

Effect of gamma ray irradiation on the structural and electrical transport properties of PrFe1?xMnxO3  

International Nuclear Information System (INIS)

The effect of gamma ray irradiation on the structural and transport properties of polycrystalline bulk samples of PrFe1?xMnxO3 (x = 0.0, 0.1, 0.5) were investigated. The samples were synthesized by solid state reaction method and exposed to 60Co 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

315

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

316

Gamma ray detector shield  

Science.gov (United States)

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26

317

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.)

318

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

319

Effect of Gamma-ray (60Co) irradiation on the C-V and G/W characteristics of Au/n-CdTe Schottky Barrier Diodes (SBDs)  

International Nuclear Information System (INIS)

In order to investigate the radiation effect on the main electrical parameters of the Au/n-CdTe Schottky Barrier Diodes (SBDs), they have been exposed to 60 Co gamma-ray source. The SBDs were irradiated at doses up to 25 kGy at room temperature. The capacitance-voltage (C-V) and conductance-voltage (G/? - V) measurements have been carried out at 1 MHz before and after radiation. Experimental results show that gamma-irradiation induce a decrease in the barrier height obtained from reverse bias C-V measurements and doping concentration, whereas series resistance increases with increasing dose. In addition, the voltage dependent series resistance profile for Au/n-CdTe SBD was obtained from admittance-based measurement method of before and after radiation

320

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.

 
 
 
 
321

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

322

The effect of {sup 60}Co ({gamma}-ray) irradiation on the electrical characteristics of Au/SnO{sub 2}/n-Si (MIS) structures  

Energy Technology Data Exchange (ETDEWEB)

The effect of {sup 60}Co ({gamma}-ray) irradiation on the electrical properties of Au/SnO{sub 2}/n-Si (MIS) structures has been investigated using the capacitance-voltage (C-V) and conductance-voltage (G/{omega}-V) measurements in the frequency range 1 kHz to 1 MHz at room temperature. The MIS structures were exposed to {gamma}-rays at a dose rate of 2.12 kGy/h in water and the range of total dose was 0-500 kGy. It was found that the C-V and G/{omega}-V curves were strongly influenced with both frequency and the presence of the dominant radiation-induced defects, and the series resistance was increased with increasing dose. Also, the radiation-induced threshold voltage shift ({delta}V{sub T}) strongly depended on radiation dose and frequency, and the density of interface states N{sub ss} by Hill-Coleman method decreases with increasing radiation dose.

Goekcen, M. [Physics Department, Faculty of Arts and Sciences, Gazi University, 06500 Teknikokullar, Ankara (Turkey); Tataroglu, A. [Physics Department, Faculty of Arts and Sciences, Gazi University, 06500 Teknikokullar, Ankara (Turkey)], E-mail: ademt@gazi.edu.tr; Altindal, S.; Buelbuel, M.M. [Physics Department, Faculty of Arts and Sciences, Gazi University, 06500 Teknikokullar, Ankara (Turkey)

2008-01-15

323

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

324

Gamma rays from globular clusters  

Science.gov (United States)

Globular clusters are known to contain a relatively large number of pulsars whose individual and collective emission in the X-ray and gamma-ray energy bands may be detectable by the instruments on board the Compton Gamma-Ray Observatory (CGRO), ROSAT, and possibly SIGMA. We discuss the several types of high-energy emission expected from isolated and interacting binary pulsars in globular clusters. Individual or collective high-energy emission from isolated pulsars is expected to be too low to be detected with current instruments. However, a class of high-luminosity hidden millisecond pulsars enshrouded in the evaporating material from irradiated companion stars can produce unpulsed shock emission detectable by the high-sensitivity instruments of ROSAT and CGRO. Establishing upper limits of high-energy emission from globular clusters will be valuable in constraining models for the formation of cluster millisecond pulsars.

Tavani, Marco

1993-01-01

325

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)

326

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. C–V 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 C–V 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

327

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. C–V 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 C–V 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

328

On the decrease of ultimate elongation of gum elastomer by irradiation  

International Nuclear Information System (INIS)

The reason why the ultimate elongation of gum elastomer decreases by irradiation was studied. The sample used is tetrafluoroethylenepropylene copolymer vulcanized which is a heat resistant elastomer. The sample was irradiated by a electron beam at room temperature. Cross-linking predominate in the operation. (Case 1) Scission predominant condition (Case 2) was given by irradiation of Co-60 ? ray at 100 deg C. Alternative irradiation of ? ray and electron beam under above condition can keep the original cross-linking density by the appropriate choice of each of the doses. (Case 3) The three cases mentioned above involve all of the cases of radiation induced aging of elastomers. Therefor, the following explanation for three cases shows the reason why the ultimate elongation of gum elastomer decreases by irradiation. Case 1. Cross-linking predominant condition. Ultimate elongation is proportional to -0.5 power of the dose. This fact can be explicable by the model of Buche, i.e. the breaking of a short chain causes another to break and that so on throughout the whole sample. Case 2. Chain scission predominant condition. Ultimate elongation increases by irradiation for a certain dose. This fact can understand by the model of Buche. But from a certain dose ultimate elongation does not increase. In the period the structure of the sample turned to be the same structure as the low molecular weight amorphose polymer vulcanized. Case 3. Rate of cross-linking and scission is the same. The average chain length does not chainge in the condition. But the distribution of chain length became wider and wider by irradiation. The increase of short chain result the decrease in ultimate elongation. (author)

329

Gamma ray auto absorption correction evaluation methodology  

International Nuclear Information System (INIS)

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

330

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

International Nuclear Information System (INIS)

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

331

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)

332

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

333

Gamma ray camera  

International Nuclear Information System (INIS)

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

334

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)

335

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

International Nuclear Information System (INIS)

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

336

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

International Nuclear Information System (INIS)

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

337

Effects of gamma ray irradiation on the radiation resistance, dielectric and mechanical properties of polyvinylchloride containing plasticizer and stabilizer  

International Nuclear Information System (INIS)

To investigate the properties of radiation resistance together with dielectric and mechanical relaxation behaviors of polyvinylchloride exposed to several different doses under the gamma ray of cobalt-60 source, experiments were carried out using the specimens prepared by mixing dibutyl-tin-dilaurate and dibutyl-tin-dimaleate as stabilizers with or without adding dioctylphthalate as a plasticizer. The origin of the absorption band at 1540-1640 cm-1 on infrared spectrum seemed to be RCOO- ion obtained from the ionization of the stabilizer, and this peak could be useful as a measure of radiation resistance on polyvinylchloride. Addition of increasing plasticizer to polyvinylchloride exhibited increasing radiation resistance and the reason for the result might be attributable to aromatic resonance adsorption of radiation energy by the dioctylphthalate. On dose dependent dielectric characteristics, nonplastized specimen showed peak at about 10 Mrad and that the peak disappeared on the plastification of specimens. Such phenomena might be explainable in considering the statistical distribution of scissored chain molecular segments as well as the plastification process of the plasticizer to polyvinylchloride chain molecules. (author)

338

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-03-01

339

Effect of {sup 60}Co {gamma}-ray irradiation on electrical properties of GaAs epilayer and GaAs p-i-n diode  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Reduction of carrier concentration and mobility of GaAs after irradiation. {yields} More introduction of Gallium vacancies compared to Arsenic vacancies. {yields} Partial conversion of shallow levels into deep levels at room temperature. {yields} Recovery of carrier mobility after thermal annealing at 300 {sup o}C in N{sub 2} ambient. -- Abstract: GaAs epilayers and p-i-n diodes structures grown using metal-organic vapor phase epitaxy were irradiated at room temperatures by {sup 60}Co {gamma}-ray radiation with varying the dose up to 50 kGy. The carrier concentration and mobility on GaAs epilayer decreases while leakage current of p-i-n diode increases at higher radiation dose (10-50 kGy). However at lower dose (<6 kGy) carrier mobility remain same but leakage current still shows significant increase. Furthermore carrier mobility of irradiated GaAs epilayers recovers partially (68%) after annealing at 300 {sup o}C while leakage current of p-i-n diode does not show any noticeable recovery. These effects are mainly due to the creation of more deep levels compared to shallow levels as determined from photoluminescence, Hall, current-voltage and electrochemical capacitance voltage analysis.

Khamari, Shailesh K., E-mail: shaileshk@rrcat.gov.i [Semiconductor Laser Section, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore (India); Dixit, V.K.; Ganguli, Tapas; Porwal, S.; Singh, S.D. [Semiconductor Laser Section, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore (India); Kher, Sanjay; Sharma, R.K. [Fiber Optics Lab, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore (India); Oak, S.M. [Semiconductor Laser Section, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore (India)

2011-02-01

340

Impacts of proton, alpha-ray, and gamma-ray irradiation on the optical and electrical properties of Cu(In,Ga)Se2 thin films and solar cells  

International Nuclear Information System (INIS)

The effects of alpha-ray, proton, and gamma-ray irradiation on the electrical properties of Cu(In,Ga)Se2 (CIGS) solar cells and the photoluminescence spectra of CIGS and CuInSe2 (CIS) thin films were investigated. Particle irradiation using alpha-ray and proton primarily degraded the interfaces of CIGS solar cells, even though the CIS and CIGS thin films did not degraded, in the case of a low irradiation fluence of the order of 109 cm-2. On the other hand, CIS and CIGS showed good to tolerance of gamma-ray irradiation because the impact of wave radiation is insufficient to degrade the crystal, in comparison with particle radiation. These results will become the first step toward realizing practical applications of CIGS solar cells in space and clarifying their degradation mechanism. (author)

 
 
 
 
341

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

International Nuclear Information System (INIS)

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

342

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

343

Determination of the axial profiles of the neutron flux in the irradiation position of Apsara reactor and the absolute fission rates of fuel specimens using high resolution gamma ray spectrometry  

International Nuclear Information System (INIS)

The axial profiles of the neutron flux in the irradiation position of the research reactor Apsara were determined by irradiating a copper wire and measuring the induced activity in copper. The absolute fission rates in the fuel specimens were determined from the measurement of the fission product gamma ray activities. The measured fission rates were compared with the values obtained from the neutron flux measurements. (author)

344

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

345

Gamma-Ray Bursts  

CERN Document Server

Gamma-ray bursts are the most luminous explosions in the Universe. They appear connected to supernova remnants from massive stars or the merger of their remnants, and their brightness makes them temporarily detectable out to the larges distances yet explored in the Universe. After pioneering breakthroughs from space and ground experiments, their study is entering a new phase with observations from recently launched satellites, as well as the prospect of detections or limits from large neutrino and gravitational wave detectors. The interplay between such observations and theoretical models of gamma-ray bursts and related objects is reviewed.

Meszaros, P

2014-01-01

346

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

347

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)

348

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-10-01

349

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 1.3–5.6 nm in size have been synthesized in sodium bis(2-ethylhexy1)sulfosuccinate (AOT)–water–isooctane micellar solutions with various [H2O]/[AOT] molar ratios (w=2.5, 5.0 or 10). Gamma irradiation method has been used to change the size and optical properties of quantum dots. It has been found that ?-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 5.2±0.4 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

350

Cosmic-ray-produced gamma rays in planetary surfaces  

Energy Technology Data Exchange (ETDEWEB)

A major priority of future NASA planetary missions is the determination of the elemental compositions of solar system objects. Gamma-ray spectroscopy will probably be used soon to determine the surface compositions of Mars and other solar system objects. Neutrons induced by the cosmic rays produce many of the important ..gamma..-ray lines that escape from planets. Some measurements of the ..gamma.. rays produced by neutrons and protons with various energies have recently been made. However, many more nuclear measurements are still needed to plan for and to interpret the results from future planetary missions. Excitation functions for the production of ..gamma..-ray lines by both neutrons and protons are needed in calculating the fluxes of ..gamma.. rays in and above a planet's surface. Thick-target irradiations with high-energy protons have simulated the production of ..gamma.. rays by the cosmic rays, and more simulations are planned. 8 refs.

Reedy, R.C.

1985-01-01

351

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

352

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

Science.gov (United States)

The cell cycle was analyzed using double staining with an anti-bromodeoxyuridine (BrdU) monoclonal antibody and propidium iodide (PI). Changes in cell kinetics after irradiation were compared with those seen by the conventional PI-based DNA histogram method. The effect of irradiation on cell kinetics has been studied primarily by counting G2-arrested cells. By the present BrdU method, a rapid transition from G1 to S-phase was observed within 2 h of irradiation, followed by G1 block. Cells in the S-phase progressed to G2+M where they arrested, resulting in a decreased percentage of S cells (18 h. The initial G1 arrest induced by irradiation was confirmed for the first time by the present BrdU-PI double staining. PMID:9458360

Murata, T; Akagi, K; Nasu, R; Kimura, H; Tanaka, Y

1998-02-01

353

Distinctions in manifestation of the hemorrhagic syndrome related to chronic, long-term and acute irradiation. [Rats;. gamma. rays  

Energy Technology Data Exchange (ETDEWEB)

Two phenomena, decrease in strength of the vascular wall and decreased amount of thrombocytes in blood, must coincide for manifestation of the hemorrhagic syndrome. Either almost simultaneous injury to the vascular wall and thrombocyte function (with acute irradiation) or dissociation of these two processes (with long-term irradiation) may be observed, depending on the radiation dose. Chronic exposure at low (subliminal) dose rates does not elicit hemorrhagic manifestations or death of rats due to pathological bleeding.

Arlashchenko, N.I.; Gorlov, V.G.; Maksimova, E.N.

1978-01-01

354

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 (2.69±0.08 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)

355

Effect of gamma-ray irradiation on hybridization between Chamaecyparis obtusa S. et Z. and C. pisifera S. et Z  

International Nuclear Information System (INIS)

The effect of gamma irradiation on the interspecific hybridization between Chamaecyparis obtusa and C. pisifera was investigated, and F1 seedlings were examined cytologically. Acute gamma irradiation and chronic gamma irradiation given throughout annual growing seasons on male flowers were effective in producing hybrids between these two species. The crossing of C. obtusa x C. pisifera was better than the reverse crossing because the pollen of C. obtusa rapidly loses its fertility, and C. pisifera blooms earlier than C. obtusa. Chronic gamma irradiation of male flowers throughout the annual growing season was slightly effective for producing the hybrids, but that of female flowers was not. Acute gamma irradiation of male flowers at the first to second telophase (300 R) was considered to be desirable for hybrid production. However, it was confirmed by cytological observation that all of the hybrids produced were triploid which had two identical genomes originated from either parent. Therefore, the unreduced male gametophytes or unreduced eggs seem to participate in the formation of the hybrids. It seems difficult to produce diploid hybrids between C. obtusa and C. pisifera. (Kaihara, S.)

356

Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation  

Science.gov (United States)

The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from 12C (4.44 MeV) and 16O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 107 oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from 16O is proportional to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring 16O PG emission.

Polf, Jerimy C.; Panthi, Rajesh; Mackin, Dennis S.; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T.; Beddar, Sam

2013-09-01

357

Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation  

International Nuclear Information System (INIS)

The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water–sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from 12C (4.44 MeV) and 16O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 107 oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from 16O is proportional to the concentration of oxygen in onal to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring 16O PG emission. (paper)

358

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

International Nuclear Information System (INIS)

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

359

Influence of irradiation with {gamma}-ray photons on the photoluminescence of Cd{sub 0.9}Zn{sub 0.1}Te crystals preliminarily subjected to the intense radiation of a neodymium laser  

Energy Technology Data Exchange (ETDEWEB)

The effect of the preliminary treatment of Cd{sub 0.9}Zn{sub 0.1}Te crystals with high-power pulses of neodymium laser radiation (the power density is {<=}1.8 MW/cm{sup 2}, at a wavelength of 532 nm) on the low-temperature (5 K) photoluminescence induced by {gamma}-ray radiation (the dose was {Phi}{sub {gamma}} = 5 kGy) is studied. The luminescence bands are related to radiation-stimulated donor-acceptor pairs, which include shallow neutral donors and neutral cadmium vacancies stimulated by {gamma}-ray irradiation, the transition of free electrons to neutral cadmium vacancies formed by radiation, and the annihilation of excitons bound to the above vacancies. It is shown that, in the crystals preliminarily treated with laser radiation, the intensity of the {gamma}-ray-stimulated luminescence bands is significantly lower than in crystals not subjected to laser radiation. This fact is accounted for by a decrease in the concentration of cadmium vacancies generated by the {gamma}-ray radiation as a result of their annihilation during the course of their interaction with laser-stimulated defects, in particular, as a consequence of their recombination at laser-stimulated interstitial cadmium atoms.

Glinchuk, K. D. [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine); Medvid' , A. P.; Mychko, A. M. [Riga Technical University (Latvia); Naseka, Yu. M.; Prokhorovich, A. V.; Strilchuk, O. M., E-mail: strilchuk@isp.kiev.ua [National Academy of Sciences of Ukraine, Lashkarev Institute of Semiconductor Physics (Ukraine)

2013-04-15

360

Gamma-Ray Burst Wallsheet  

Science.gov (United States)

The Gamma-ray Burst Wallsheet was developed to illustrate the properties of light emanating from a gamma-ray burst as seen by three distant satellites, including NASA's Swift. The back of the wallsheet has one of the three activities in the accompanying educator guide (Angling for Gamma-ray Bursts).

2005-01-01

 
 
 
 
361

Chemist's gamma-ray table  

International Nuclear Information System (INIS)

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

362

2-((aminopropyl)amino)ethanethiol (WR1065) is anti-neoplastic and anti-mutagenic when given during /sup 60/Co. gamma. -ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

The effect of 2((aminopropyl)amino)ethanethiol (WR1065) has been studied on the induction of neoplastic transformation using 10T1/2 cells and on mutation of the hypoxanthine guanine phosphoribosyl transferase (HGPRT) locus using Chinese hamster V79 cells. The first observations that treatment of 10T1/2 cells with 1 mM WR1065 for a total of 35 min during irradiation with /sup 60/C ..gamma..-rays significantly reduces the incidence of neoplastic transformation while having no effect on cell viability are reported. In a similar experiment with V79 cells in which 4mM WR1065 was used, a significant reduction in mutation frequency at the HGPRT locus and significant protection against cell killing was found. These results suggest that WR1965 acts to modulate both acute damage and sub-lethal processes that lead to mutation and neoplastic transformation. Beyond the purely mechanistic approach of these studies, the potential application of these agents to minimizing the long-term neoplastic effects of radiation or chemotherapeutic agents currently in use for treating potentially curable cancer patients should be further investigated.

Hill, C.K.; Nagy, B.; Peraino, C.; Grdina, D.

1986-04-01

363

Generation of paramagnetic centers in bulk SiO2 and Si/SiO2 structures by gamma-ray irradiation  

International Nuclear Information System (INIS)

Pb (.Si?Si3) and Eprime (.Si?O3) centers in Si/SiO2 structures and Eprime centers in bulk SiO2 created using gamma-ray radiation have been studied with the electron spin resonance (ESR) technique. Si/SiO2 structures on (111), (110), and (100) planes were obtained using three kinds of oxidation methods to control the concentration of the hydrogen-related impurities. Bulk SiO2 was fabricated with the vapor phase axial deposition (VAD) method. It is first observed that the concentration of Pb centers reaches the equilibrium concentration with increasing accumulated dosage. The concentration of Eprime centers also increases with the accumulated dosage. Concentration of Eprime center in Si/SiO2 under irradiation is larger than that in bulk SiO2 by a factor of ?20-100. The variation of the Eprime center concentration in Si/SiO2 structures is close to that in densified bulk SiO2. ((orig.))

364

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

Energy Technology Data Exchange (ETDEWEB)

'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 {sup 60}Co 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)

Masuda, Tetsuo; Yoshioka, Toji; Kotobuki, Kazuo; Sanada, Tetsuro [Institute of Radiation Breeding, Omiya, Ibaraki (Japan); Inoue, Kosuke; Murata, Kenji; Kitagawa, Kenichi; Tabira, Hiroki; Yoshida, Akira

1997-06-01

365

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

Science.gov (United States)

A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of 235U by monitoring its delayed high energy ?-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of 235U in the oxide samples with this set-up is estimated to be 14 mg.

Andola, Sanjay; Niranjan, Ram; Kaushik, T. C.; Rout, R. K.; Kumar, Ashwani; Paranjape, D. B.; Kumar, Pradeep; Tomar, B. S.; Ramakumar, K. L.; Gupta, S. C.

2014-07-01

366

Effects of gamma-ray irradiation on interspecific hybridization between Chamaecyparis obtusa S. et Z. and Chamaecyparis pisifera S. et Z  

Energy Technology Data Exchange (ETDEWEB)

C. obtusa S. et Z. is one of the most important forest trees in Japan, and possesses high wood quality. It adapts to dry or semi-dry planting sites, but when it is planted in humid and productive soil, physiological damage is often seen, and its woods are not resistant against termite harm. On the contrary, C. pisifera S. et Z. has high adaptability to humid and productive soil, and is resistant against termite harm. In order to improve the resistance of C. obtusa against diseases and insects, an attempt to obtain a hybrid between C. obtusa and C. pisifera has been made. However, it was found to be very difficult to obtain the hybrid because of low cross compatibility. Therefore, the radiosensitivity of reproductive organs and the induction of mutation in C. obtusa and C. pisifera, the cause of interspecific incompatibility between both species, and the possibility of breaking down the incompatibility were investigated. Also, the cytological screening of the hybrids between C. obtusa and C. pisifera was made. It was considered that the acute gamma-ray irradiation from 500 to 600 R on male flowers was optimum for the hybridization of the present purpose. All of the hybrids produced in this study were triploid.

Maeta, Takehiko (Institute of Radiation Breeding, Omiya, Ibaraki (Japan))

1982-03-01

367

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

International Nuclear Information System (INIS)

In the present study, we have used various rice cultivars such as Nipponbare, Tamxoan Hai Hau and mutagenized TDB06 which was obtained from Tamxoan Hai Hau calli irradiated by gamma-ray 60Co with the aim of cloning, sequencing and investigating the molecular mutants of GA2ox1 gene which regulates the height of rice cultivars. Interestingly, we have found that the nucleotide sequence of GA2ox1 gene of mutagenized TDB06 is slightly changed compare to that of original Tamxoan Hai Hau and Nipponbare. The GA2ox1 gene sequence differences of mutagenized TDB06 compared to Tamxoan Hai Hau and Nipponbare are 9 and 2 nucleotides, respectively. We have also shown that the amino acid sequence of GA2ox1 protein is also different among various cultivars in which amino acids corresponding to positions 137 (Alanine), 167 (Threonine), 222 (Valine), 227 (Histidin) of mutagenized TDB06 were replaced with other amino acids Valine, Alanine, Arginine and Lysin, respectively. Nucleotide sequences of GA2ox1 gene isolated from mutagenized TDB06 and Tamxoan Hai Hau cultivars have been registered in Genbank/NCBI with accession numbers EF164903 and EF164904. Based on these initial results, we continuously isolate genes related to dwarf character, construct vectors and do transformation. This strategy can significantly contribute to improve efficiency of rice breeding in Vietnam. (author)

368

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

369

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

370

Dynamic hormonal changes in the thyroid axis following acute irradiation of rats with different gamma rays doses  

International Nuclear Information System (INIS)

Male sexually mature Wistar rats were exposed to gamma-radiation from cesium source Igur-1 with emissive power 1,26 Gy/min. Dose of 0,5, 1,0, 2,0 and 4,0 Gy were applied. Ten aminals from each irradiation dose (total 40 for all doses) were killed by blood letting and the content of the thyroid axis hormones TSH, T3 and T4 was determined by radioimmunoassay. The normal levels of these hormones were determined in 10 animals. It was found that the content of TSH, T3 and T4 was altered as early as the first few post-irradiation days: T3 and T4 incretion by the tyhroid was inhibited, while TSH produced by the anterior hypophysis was essentially increased in the first 5 or 6 days. After the sixth and especially after the twelfth day there occurred total hypothyroidism of central and peripheral nature; the effect was strongest on TSH and T4 and to a lesser degree on T3. The changes in the plasma content of thyroid axis hormones were influenced by the irradiation dose: hypothyroidism was most pronounced with the use of the highest irradiation doses of 2,0 and 4,0 Gy

371

Liver Histophatological Studies of Mice (Mus musculus sp. Infected With Gamma Rays Irradiated Plasmodium berghei Strains Anka  

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Full Text Available Malaria is a serious global disease and a leading cause of morbidity and mortality in tropical and sub-tropical countries. Radiation attenuated vaccines have been demonstrated to be an effective means of controlling certain parasitic infections such as malaria. Our previous research showed that irradiation dose of 150-175 Gy to Plasmodium berghei were enable to suppress the infected erythrocyte cells and irradiation dose at 150 Gy was more effective compared to 175 Gy in attenuate the parasites based on parasitemia index. Aim of this research was to investigate the most suitable irradiation dose to attenuated P. berghei based on the the histological changes in the liver mouse malaria model. Histological changes in mice liver because of Plasmodium is congestion in the sinusoids and masses of hemozoin. Fourty Swiss mice were randomly assigned to four equal groups. First group of mice were inoculated with the unirradiated malaria parasites as a positive control while negative control group represented uninfected normal control. The third group of mice was inoculated with the irradiated malaria parasites with dose 175 Gy. Last group were inoculated with the irradiated malaria parasites with dose 150 Gy. Mice were sacrificed at day 6, 8, 12, 16, 20, and 24 post inoculation for liver histological study. Their livers processed for histomorphometric assessment of sinusoidal area, haemozoin area and hepatosomatic index as a quantitative measure of altered morphology. Hepatic sinusoidal area in mice infected with the unirradiated malaria parasites increased by 104% in day 24 post inoculated compared to day 6 post inoculated, whereas a smaller increase of 46% occurred in mice that were inoculated with the irradiated malaria parasites with dose 150 Gy. The difference between positive control and 150 Gy group was significant (P 0.05. For hepatosomatic index (HSI at day 24 post inoculation the HSI value in group 150 Gy (5.33 was the smallest compared to other groups. Based on our research it can be concluded that irradiation dose at 150 Gy was more effective compared to 175 Gy in attenuate the parasites based on assessment of sinusoidal area, and HSI value at 24 day post inoculation.

TUR RAHARDJO

2013-09-01

372

Burn-up profiling of PHWR by high resolution gamma-ray spectrometry of irradiated Zr-2.5%Nb pressure tubes  

International Nuclear Information System (INIS)

'Full text:' Zr-2.5%Nb Pressure tubes, being used in Indian PHWRs from Kakrapar Atomic Power Station, unit 2 (KAPS-2) onwards, are subjected to long term irradiation (around 30 years). The mono-isotopic element niobium with a thermal neutron cross-section of 1.15 barns, generates significant amount of the radionuclide 94GNb, whose half-life is as long as 20,300 years. Of course, 94GNb is also produced by the decay of its short-lived isomer 94mNb (T1/2 = 6.26 min). Hence, the amount of the radionuclide 94GNb produced in the pressure tube is a permanent record of the neutron fluence it is exposed during its residence period in the reactor. The pressure tube from the coolant channel S7 was taken out of the reactor, after a residence time of 8 effective full power years for surveillance. Gamma-ray spectra are obtained on samples of about 20 mg each, taken from 13 positions along the 5100 mm length of the pressure tube using an efficiency calibrated HPGe detector in Compton suppression mode for durations of 1000 to 9000 sec, after a cooling period of 3.3 years. The prominent gamma ray activity in all the samples is from 94GNb (702 and 871 keV) and 60GCo (1173 and 1332 keV). The other radio-nuclides present in these samples include 125Sb, 54Mn, 182Ta, 125mTe, 95Nb and 95Zr. The absolute activities of all these radio-nuclides were determined from the peak areas of these spectra using the absolute detection efficiency of the detector determined with a standard 152Eu source. The spectral data was used to generate the axial profiles of the activities of the two radionuclides 94GNb and 60GCo for the two gamma ray activities for each of them along the length of the tube, which on normalisation showed good consistency. This profile should represent the average neutron flux seen by the tube, though several fuel bundles stay at each of the 12 locations in the channel for various residence periods adding to the corresponding 8 effective full power years of reactor operation. The profile obtained is compared with that generated by theoretical models. Also this neutron fluence profile is correlated with the burn up profile of the channel computed from the burn up data of all the fuel bundles stayed in the channel in the residence period. These measurements, when performed on the pressure tubes in some more selected channels, would go a long way in experimentally generating the radial and axial power distribution of the core for the relevant residence period. (author)

373

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

Science.gov (United States)

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.

Zia, Khalid Mahmood; Bhatti, Ijaz Ahmad; Barikani, Mehdi; Zuber, Mohammad; Sheikh, Munir Ahmad

2009-05-01

374

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