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1

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

CERN Multimedia

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

Studies on mechanical properties and fractography of. gamma. -ray irradiated blends of plasticized poly(vinyl chloride) and thermoplastic copolyester elastomer  

Energy Technology Data Exchange (ETDEWEB)

The mechanical properties and fracture mode of /sup 60/Co ..gamma..-ray irradiated blends of plasticized poly(vinyl chloride) (PVC) and thermoplastic copolyester elastomer (Hytrel 40D) have been investigated with specific reference to the effect of blend ratios and absorbed radiation doses. Samples were irradiated in the dose range of 0.1-50 Mrad in air at room temperature (25/sup 0/C) at the rate of 0.321 Mrad/h. The elongation at break, tear strength and tensile set after failure of all the samples remain unchanged up to an absorbed dose of 1 Mrad but showed considerable reduction at higher radiation doses. The morphology of the irradiated surfaces after an absorbed dose of 50 Mrad has been examined by scanning electron microscope (SEM). SEM studies on the tensile and tear fracture surfaces also have been undertaken in order to gain an insight into the mechanism of failure.

Thomas, Sabu; Gupta, B.R.; De, S.K.; Thomas, K.T.

1986-01-01

4

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

UK PubMed Central (United Kingdom)

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.

Murray KA; Kennedy JE; McEvoy B; Vrain O; Ryan D; Cowman R; Higginbotham CL

2013-01-01

5

Effects of gamma ray irradiation on sensitivity of photochromic glasses  

International Nuclear Information System (INIS)

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

1978-01-01

6

Synthesis of lipid membrane analogues by {gamma}ray-irradiation  

Energy Technology Data Exchange (ETDEWEB)

The degree of polymerization is readily controllable by adjusting the initial molar ratio of 3-mercaptopropyltrimethoxysilane and octadecylacrylate in both radical telomerization using AIBN and {gamma}-ray irradiation. (author)

Hirayama, Chuichi [Kumamoto Univ. (Japan). Faculty of Engineering; Ihara, Hirotaka; Sakata, Masayo; Tanaka, Hideaki

1997-01-01

7

Inactivation of citrus tristeza virus by gamma ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

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

Ieki, Hiroyuki; Yamaguchi, Akira

1984-12-01

8

Irradiated thermoplastic elastomer  

International Nuclear Information System (INIS)

[en] A thermoplastic elastomer which is processable after irradiation comprises a diblock copolymer which is irradiated at a dose level of from about 0.1 to about 3.0 times the gel dose. The resulting diblock copolymer elastomer has improved physical strength and is readily processable. The diblock copolymer has one block portion made from an olefin having from 2 to 12 carbon atoms, a conjugated diene having from 4 to 12 carbon atoms, or combinations thereof. The remaining block portion is made from vinyl aromatic monomers having from 3 to 15 carbon atoms. A triblock copolymer may be added to the diblock copolymer to form a blend which is irradiated at the same dose level. The triblock copolymer has a central block portion which is also made from the above-noted olefins, conjugated dienes, or combinations thereof, and end portions which are also made from the above-noted vinyl aromatic monomers. (Auth.)

1977-01-25

9

[Immunogenicity in Salmonella gallinarum-pullorum irradiated with gamma rays  

UK PubMed Central (United Kingdom)

Studied with the imunogenicity of Salmonella gallinarum-pullorum bacteria treated with 1, 10 and 20 MR gamma rays or killed with acetone. Bacterial cultures were irradiated with a LMB-gamma M device, having a 137Cs source, single doses being of a 3,252 R/min power Biozzi's clearance test was employed to determine the changes in the immunogenic properties of the irradiated bacteria. The results obtained with both the clearance test and the protection test spoke of a considerable drop in the immunogenic capacity of the irradiated bacteria, using rates of 10, and especially of 20 MR gamma rays as compared to those killed with acetone. Protection was manifested best by bacteria treated at the rate of 1 MR gamma-rays, which pointed to the possibility of their practical use in the immunoprophylaxis of pullorum disease in birds.

Stefanov V; Stefanova M; Belimezov I

1977-01-01

10

Gamma ray irradiation to semi-purified diet  

International Nuclear Information System (INIS)

[en] 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.)

1976-01-01

11

Effect of spirit irradiation with 60Co gamma-rays  

International Nuclear Information System (INIS)

A few sorts of spirit were irradiated with a dose of 1 or 5 Mrad of 60Co gamma-rays. Then the chemical composition of spirits was investigated. It was found that as a result of irradiation the content of acids, esters, acetal aldehydes and methanol increases, while the strength of higher alcohols decreases slightly. The changes of compounds content in particular spirits are dependent on radiation doses and chemical composition before irradiation. It was also discovered that spirit irradiation causes decrease or even disappearance of characteristic - for given spirits - maxima of UV absorption. (Z.M.)

1975-01-01

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)

2011-01-01

13

Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation  

CERN Multimedia

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

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

2002-01-01

14

Gamma-rays irradiation effects on polysulfone at high temperature  

International Nuclear Information System (INIS)

The temperature dependence of the irradiation effects on polysulfone was studies by measuring the molecular weight, glass transition temperature, gel fraction and evolved gas. Polysulfone was irradiated with gamma-rays at room temperature, 100, 150, 180 and 210 deg. C. The change of molecular weight distribution and glass transition temperature showed occurrences of a main chain scission at room temperature and cross-linking at high temperature. The decrease of gel dose, the increases of gel fraction and total gas evolution with increasing temperature was observed. The evolution of CO, CO2 and SO2 gases increased at high temperature, while yield of evolved H2 was independent of irradiation temperature. The probability of the cross-linking was clearly increased by irradiation at high temperature above 180 deg. C, though the chain scission was not changed very much.

2007-01-01

15

Depolymerization of schizophyllan by gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Schizophyllan, an antitumor (1 [yields] 3)-[beta]-D-glucan that takes on a triple helical structure in aqueous solution, was irradiated with gamma-ray at doses of 0.058 to 8.4 Mrad. The molecular weight of the polysaccharide decreased as the dose of radiation increased, and the number of reducing group increased. Methylation analysis by enzymic hydrolysis with exo-[beta]-1,3-glucanase and antitumor tests showed that the polysaccharide after irradiation at 0.058 or 0.26 Mrad had essentially the same chemical structure and antitumor activity as native schizophyllan. Treatment at 2 or 8.4 Mrad caused changes in the chemical structure and antitumor activity. The depolymerization mechanism seemed to be different from that caused by ultrasonic treatment or hydrodynamic shearing, because irradiation most readily caused changes in the chemical structure and antitumor activity. (author).

Tabata, Kengo; Ito, Wataru; Hirata, Akio; Kojima, Takemasa (Taito Co. Ltd., Kobe (Japan). Research Lab.)

1992-11-01

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)

1985-01-01

17

Photoconductivity of polyethylene pre-irradiated by gamma-ray  

International Nuclear Information System (INIS)

[en] 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)

1984-01-01

18

Water radiolysis in a crack tip under gamma ray irradiation  

International Nuclear Information System (INIS)

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

2002-01-01

19

Water radiolysis in a crack tip under gamma ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Under a non-irradiation condition, oxidant, e.g., O{sub 2} and H{sub 2}O{sub 2}, in a crack tip is supplied from the bulk water. But under irradiation conditions, even if the diffusion of radiolytic species is not sufficient, direct radiolysis in the crack tip causes high concentrations of radiolytic species. As a result of measurements and Monte Carlo calculation of gamma ray energy deposition, it has been confirmed that the energy deposition rate in the gap water is larger than that in the bulk water. The energy absorption rate increases as the gap width decreases and reaches 1.3 times that in the bulk water. In order to evaluate crack propagation rate for irradiation assisted stress corrosion cracking (IASCC) of stainless steel, a water radiolysis model in a crevice is proposed. A larger energy deposition rate in the crevice water produces many more radiolytic species, which causes high oxidant concentrations in spite of enhanced recombination of the species at the crevice inner surface. So, for IASCC evaluation, crevice water chemistry plays an important role to determine the crack propagation rate under irradiation. (authors)

Satoh, Tomonori; Uchida, Shunsuke; Satoh, Yoshiyuki [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku Univ., Sendai (Japan)

2002-07-01

20

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

International Nuclear Information System (INIS)

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

1990-01-01

 
 
 
 
21

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

Energy Technology Data Exchange (ETDEWEB)

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

Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo (Hokkaido Univ., Hakodate (Japan). Faculty of Fisheries); Hayashi, Toru; Yasumoto, Kyoden

1990-10-01

22

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

International Nuclear Information System (INIS)

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

2006-12-21

23

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

Energy Technology Data Exchange (ETDEWEB)

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(..gamma..,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.

Phillips, J.R.; Halbig, J.K.; Lee, D.M.; Beach, S.E.; Bement, T.R.; Dermendjiev, E.; Hatcher, C.R.; Kaieda, K.; Medina, E.G.

1980-05-01

24

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

1980-01-01

25

Degradation of perfluoroalkylpolyether Oils by. gamma. -ray irradiation under vacuum conditions  

Energy Technology Data Exchange (ETDEWEB)

Four kinds of fluorine group lubricating oil having different molecular structures were irradiated with Co-60 gamma ray in vacuum, and their behavior of deterioration was compared and examined by ESR, mass spectrometer, IR, liquid chromatograph and so on. FZ oil has acetal bond, and is apt to form radicals already at the initial stage of decomposition due to the absorption of gamma ray. It was found that accompanying the decomposition, the gas with low molecular weight like fluorine compounds was generated, and particularly in FZ oil, by the depolymerization from the end of acetal bond, a large quantity of carbonyl fluoride was generated. Except D oil, the viscosity lowered by gamma ray irradiation. In the case of D oil, since the radical is stable, cross linking and polymerization occurred, and the viscosity seemed to increase. Besides, it was found that since the distribution of molecular weight became wide, the deterioration of PFPE oil occurs under the competition among decomposition, cross linking and polymerization. Moreover, by gamma ray irradiation, -CFO radical was formed at the end of molecules, and the total acid value was heightened. The deterioration of PFPE oil by gamma ray irradiation depends on the molecular structures in this way. (K.I.).

Mori, Shigeyuki; Shitara, Yuji (Iwate Univ., Morioka (Japan). Faculty of Engineering); Seguchi, Tadao; Nishimura, Jun

1991-10-01

26

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)

2008-01-01

27

Genotoxicological safety of the {gamma}-ray irradiated herbs: astragali radix, atractylodes rhizoma and cimicifugae rhizoma  

Energy Technology Data Exchange (ETDEWEB)

This experiment was performed to test the genotoxicological safety of the three medicinal herbs-Astragali Radix, Atractylodes Rhizoma and Cimicifugae Rhizoma-irradiated with {gamma}-rays. The hot water extracts of the herbs irradiated with {gamma}-rays (10 kGy) were examined in two short-term in vitro tests : (1) Ames test in Salmonella typhimurium TA 98 and Ta 100, (2) Micronucleus test in cultured Chinese hamster ovary (CHO) cells. No mutagenicity was detected in these two assays with or without metabolic activation by S9 mix. From these results, the safety of the herbs irradiated with {gamma}-rays at practical doses could be revealed in further tests of genotoxicity in vivo, chronic and reproductive toxicity.

Ham, Y. H.; Oh, H.; Park, H. R.; Beon, M. W.; Cho, S. K. [KAERI, Taejon (Korea, Republic of)

2001-05-01

28

Prevention of adverse effects of. gamma. -ray irradiation after metallothionein induction by bismuth subnitrate in mice  

Energy Technology Data Exchange (ETDEWEB)

The effect of preinduction of metallonthionein (MT) by bismuth subnitrate (BSN) on the adverse effects and antitumor activity of {gamma}-ray irradiation was investigated in mice. Preinduction of MT by oral administration of BSN significantly reduced the lethal effects and bone marrow injury caused by total body irradiation with {gamma}-rays. A significant increase in the MT concentration in bone marrow was observed in mice treated with BSN. In tumor-bearing mice, pretreatment with BSN did not compromise the antitumor activity of {gamma}ray irradiation although bone marrow injury was remarkably suppressed. These results suggest that BSN pretreatment is an effective method for protection against side-effects in radiotherapy. (author).

Satoh, Masahiko; Miura, Nobuhiko; Naganuma, Akira; Imura, Nobumasa (Kitasato Univ., Tokyo (Japan). School of Pharmaceutical Sciences); Matsuzaki, Norio; Kawamura, Eiji (Kitasato Inst. Hospital, Tokyo (Japan))

1989-12-01

29

Effect of gamma irradiation dose on the fabrication of ?-elastin nanoparticles by gamma-ray crosslinking  

International Nuclear Information System (INIS)

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

2011-01-01

30

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-05-15

31

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

Energy Technology Data Exchange (ETDEWEB)

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 {gamma}-ray equivalent absorbed dose (ED) which creates the same concentration of radicals is obtained by the additive {gamma}-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).

Ikeya, Motoji (Osaka Univ., Toyonaka (Japan). Dept. of Physics); Baffa, F.O. (Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, SP (Brazil)); Mascarenhas, Sergio (Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica)

1989-01-01

32

Measurement of the ash content of iron-rich coals by gamma-ray irradiation  

International Nuclear Information System (INIS)

[en] Ash contents of some coal samples from Enugu mines in Nigeria were measured using gamma-ray irradiation technique. The method employed gamma-ray energies of 0.060, 0.662 and 1.33 MeV of 241Am, 137Cs and 60Co, respectively, and a counting system with a scintillation detector. The sensitivity of the method was observed to decrease drastically with increase in ash content above 35% ash, and with increase in energy of the gamma-ray. Further analyses showed that the error in the ash content determination was due to iron content which was not constant, but increased with ash content, with width variation above a mean value of +-0.64% Fe2O3. (author) 9 refs.; 5 figs.; 2 tabs

1989-01-01

33

Functionalization of gold and carbon nanostructured materials using gamma-ray irradiation  

International Nuclear Information System (INIS)

Gold nanoparticles were successfully attached to the surface sites of carbon nanotubes (CNT). Both nanostructured materials were functionalized by ?-ray irradiation without chemical treatments for creating active sites. UV-visible absorption spectra of the un-irradiated and gamma ray-irradiated nanomaterials are also studied. The absorption spectrum of the irradiated CNT shows a new strong peak located at 700 nm, which might act as the active site on the surface of CNT, the result being an attachment of gold nanoparticles. This approach provides an efficient method to attach other nanostructures to carbon nanotubes for using them in different applications such as medicine and synthesis of catalytic materials.

2009-01-01

34

Functionalization of gold and carbon nanostructured materials using gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Gold nanoparticles were successfully attached to the surface sites of carbon nanotubes (CNT). Both nanostructured materials were functionalized by {lambda}-ray irradiation without chemical treatments for creating active sites. UV-visible absorption spectra of the un-irradiated and gamma ray-irradiated nanomaterials are also studied. The absorption spectrum of the irradiated CNT shows a new strong peak located at 700 nm, which might act as the active site on the surface of CNT, the result being an attachment of gold nanoparticles. This approach provides an efficient method to attach other nanostructures to carbon nanotubes for using them in different applications such as medicine and synthesis of catalytic materials.

Salah, Numan [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)], E-mail: alnumany@yahoo.com; Habib, Sami S.; Khan, Zishan H. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Al-Hamedi, Salim [Department of Biological Science, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Djouider, Fathi [Department of Nuclear Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2009-11-15

35

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

International Nuclear Information System (INIS)

[en] 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)

1979-12-05

36

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

Energy Technology Data Exchange (ETDEWEB)

The major advantages of Bi{sub 4}Ge{sub 3}O{sub 12}(BGO) are its high density(7.13 g/cm{sup 3}) 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 mm{sup 3} size. In this work, we measured and compared the radiation damage of BGO crystal at accumulated doses of 1 kGy and 10 kGy using {sup 60}Co gamma-rays.

Cho, Yun Ho; Kang, Sin Yang; Park, Byeong Hyeon; Lee, Seung Kyu; Lee, Dong Hoon; Kim, Yong Kyun [Hanyang University, Seoul (Korea, Republic of); Park, Jae Woo [Cheju National Univ., Jeju (Korea, Republic of)

2008-05-15

37

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 using 60Co gamma-rays.

2008-01-01

38

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.).

1982-01-01

39

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

40

Dielectric breakdown of {gamma}-ray irradiated epoxy resin with alumina  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we report on dielectric breakdown characteristics of alumina-filled epoxy resin irradiated by {gamma}-ray under a needle-plane electrode geometry. For that purpose, we studied relationship between breakdown voltage and filler parts, relationship between breakdown voltage and irradiation dose, and an influence of thickness of epoxy resin on breakdown voltage. In order to investigate these results, we made further experiments on Glass Transition Temperature change before and after {gamma}-ray irradiation using a DSC method, and filler parts dependence of tan {delta} and {epsilon}. We also investigated surface oxidization of epoxy resin from a wave analysis of spectra measured using FT-IR difference spectrometer. We observed surfaces of epoxy resin before and after {gamma}-ray irradiation using a Scanning Electron Microscope (SEM). The results are as follows: (1) In the case of 2 mm thick, dielectric breakdown voltage of epoxy resin increases suddenly from 5 parts to 40 parts, and decreases slowly from 40 parts to 300 parts, under both positive and negative impulse voltage. (2) Dielectric breakdown voltage of epoxy resin with 2 mm thick begins to decrease at 2 MGy under positive impulse voltage, but it begins to decrease at 5 MGy under negative impulse voltage. (author).

Ruike, Mitsuo [Hachinohe National Coll. of Technology, Aomori (Japan); Fujita, Shigetaka; Noto, Fumitoshi

1995-07-01

 
 
 
 
41

Gamma-ray irradiation of a boreal forest ecosystem  

International Nuclear Information System (INIS)

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

1983-01-01

42

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-02-01

43

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

International Nuclear Information System (INIS)

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

1998-01-01

44

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

Energy Technology Data Exchange (ETDEWEB)

The corrosion behavior of austenitic stainless steel (R-SUS304ULC) was studied in boiling pure nitric acid solution under gamma-ray irradiation. Corrosion experiments, immersion and electrochemical tests including the measurement of potential, polarization curve and AC impedance. were carried out by making use of a {sup 60}Co gamma-ray source in order to evaluate the gamma-ray effect on corrosion of 304ULC. The radiolysis products of nitric acid, furthermore, were analyzed to discuss the electrochemical effect of the gamma-ray irradiation on the pure nitric acid solution. Consequently, it was recognized that the corrosion of 304ULC in boiling pure nitric acid solution was slightly accelerated by gamma-ray irradiation, though it is insignificant from an engineering viewpoint. In contrast with this trend, the corrosion potential of 304ULC(E{sub corr}) and the redox potential of pure nitric acid solution were induced to shift towards the less noble ride by gamma-ray irradiation. This shift of potential is concerned with the radiolysis products of nitric acid such as NO{sub x} and HNO{sub 2} formed in dependence on exposure dose rate. The acceleration of corrosion is considered as caused by an enhancement in the current across the passive film by the gamma-ray irradiation on the stainless steel surface. (author)

Takeuchi, M.; Nagai, T.; Takeda, S. [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan); Yamamoto, T. [Osaka Univ., Suita (Japan). Dept. of Nuclear Engineering; Tsukui, S.; Okamoto, S. [Osaka Prefectural, Research Institute for Advanced Sciences and Technology, Univ., Sakai (Japan)

1998-07-01

45

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

International Nuclear Information System (INIS)

Livestock wastewater generally contains high strength of organics (COD), ammonia nitrogen (NH4+ -N), phosphate phosphorus (PO43- -P) and suspended solids. It is very difficult to treat by conventional wastewater treatment techniques. In this study, struvite crystallization was carried out to treat the digested livestock wastewater. 1.0 :1.2 :1.2 was determined as an optimal NH4+ :Mg2+ : PO43- mol ratio of struvite crystallization. For the digested livestock wastewater, COD, NH4+ -N and PO43- -P removal efficiencies by struvite crystallization were 72.4%, 98.9%, and 74.8%, respectively. Gamma-ray irradiation was carried out prior to struvite crystallization of livestock wastewater. The enhancement of struvite crystallization efficiency could be obtained by the pretreatment of gamma-ray irradiation due to the decrease of COD, NH4+ -N and PO43- -P concentration

2009-01-01

46

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

International Nuclear Information System (INIS)

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

1999-01-01

47

The gamma ray effect crystalline materials in reactor irradiation  

International Nuclear Information System (INIS)

Experiments on irradiation of diamond, graphite and reactor steel are described under different gamma-radiation. It is shown, that gamma-quanta are conducive to defect annealing. In particular, volume of diamond crystal lattice and C parameter of graphite lattice increase when gamma-particle flux decreases. Gamma-radiation flux decreasing leads to deterioration of mechanical properties of reactor steel. 6 refs., 3 figs.

1994-01-01

48

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

49

Glasses, Coatings, Glues and Gamma-ray Irradiation  

International Nuclear Information System (INIS)

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

2001-01-01

50

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.

1988-01-01

51

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

International Nuclear Information System (INIS)

[en] 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)

2002-01-01

52

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-12-01

53

Effect of gamma-ray irradiations on optical filter glass  

International Nuclear Information System (INIS)

Five types of Schott glass (GG435, GG455, GG475, BG18, and BG38) have been irradiated up to 1 Mrad using 1.2-MeV ? rays from a Co60 source. The effect of the irradiation on the transmittance of the glasses was studied as a function of the dose for wavelengths up to 800 nm. Three parameters are used to describe the increase of the optical thickness: the saturation coefficient in inverse millimeters, the slope in inverse kilorads times inverse millimeters, and the saturation speed in kilorads; they are given as a function of wavelength. For each glass, a single color center could explain the increase in the optical thickness. This single color center creates three Gaussian-shaped absorption bands that apply to both the saturation coefficient and the slope; the energy, the full width at half maximum, and the amplitude of these bands are given. The data can be used either by an engineer for predicting radiation damage and for choosing the best glass for a given application or by a scientist interested in solid state physics. Guidelines for minimizing the effect of radiation on glass are given and applied to a space experiment to be flown in 1995 on the European Space Agency/National Aeronautics and Space Agency (ESA/NASA) Solar and Heliospheric Observatory (SOHO) spacecraft.

1994-01-01

54

Gamma-rays irradiation of greenwood cuttings cherry varieties  

International Nuclear Information System (INIS)

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

1975-01-01

55

Economic effectiveness of irradiation with gamma rays on maize grains  

International Nuclear Information System (INIS)

[en] 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

1985-01-01

56

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1990-11-01

57

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

International Nuclear Information System (INIS)

[en] 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

1999-01-01

58

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

59

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

60

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

International Nuclear Information System (INIS)

[en] 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)

1989-01-01

 
 
 
 
61

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

2012-01-01

62

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

63

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

International Nuclear Information System (INIS)

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

2013-01-01

64

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

Energy Technology Data Exchange (ETDEWEB)

Packaging materials for food made of polyethylene, polypropylene and polystyrene were irradiated with {sup 60}Co {gamma}-ray. Exposure was 10, 30 and 50 kGy at 5 kGy/h exposure rate. With irradiating, all packaging materials of polyethylene and polypropylene produced volatile substances, for example, aldehydes, ketones and alcohols, especially, large amount of acetic acid and acetone. These volatile compounds were not observed in the sample unirradiated and increased with increasing exposure. Accordingly, it is concluded that they were decomposition products depend on irradiation. Polypropylene products were much more easily decomposed than polyethylene one because much more kinds and amount of volatile products were formed. However, on polystyrene products, content of styrene and ethylbenzene, monomer of raw materials, were reduced by irradiation and small amount of volatile substances were formed. These results proved its resistance to irradiation. (S.Y.)

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

1998-02-01

65

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

International Nuclear Information System (INIS)

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

1994-01-01

66

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

International Nuclear Information System (INIS)

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

2012-01-01

67

Effect of [gamma]-ray irradiation on the electrical conductivity of [beta]-PbF[sub 2  

Energy Technology Data Exchange (ETDEWEB)

Effect of [gamma]-ray irradiation on polycrystalline [beta]-PbF[sub 2] was investigated by X-ray, Raman scattering and electrical conductivity. With an increase in the dose of [gamma]-ray irradiation, the halfline width of Raman peak increased, suggesting the formation of Frenkel defects. In the other hand, the electrical conductivity decreased with an increase in the irradiation dose. The motion of the formed interstitial F[sup -] ions is presumed to be hindered by unidentified defects formed simultaneously by the irradiation. (orig.)

Nagai, Masayuki (Musashi Inst. of Tech., Tamazutsumi (Japan)); Kushida, Teruo (Musashi Inst. of Tech., Tamazutsumi (Japan)); Nishino, Tadashi (Musashi Inst. of Tech., Tamazutsumi (Japan))

1993-07-01

68

Irradiation effects of proton and gamma-ray on CVD diamond detector  

International Nuclear Information System (INIS)

Irradiation effects of proton and gamma-ray on a CVD diamond detector were studied on Beijing Tandem accelerator and 60Co source. The decrease of the detector's signal current was less than 3.5% after irradiated by 1013 cm-2, 9 MeV continuous protons. Dark current didn't change obviously after the proton irradiation. The calculated radiation damage coefficient is 1.3 x 1016 ?m-1?cm2, which is much higher than that of Si PIN detectors. The signal current increased a little after irradiated by 10.32 C/kg and 1.25 MeV ?-ray, as the electrons excited by ?-ray can deduce traps in diamond. And the increase is less than 0.7%. Diamond detector has high radiation hardness and can be used in high radiation detection. (authors)

2008-01-01

69

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

International Nuclear Information System (INIS)

[en] 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.)

1984-01-01

70

Radiation stability test of DEHPA and TBP extractants by irradiation with cobalt-60 gamma-rays  

International Nuclear Information System (INIS)

This study was carried out to evaluate the radiation stability of di-(2-ethylhexyl) phosphoric acid (DEHPA) and tributyl phosphate (TBP) extractants by irradiation with Cobalt-60 gamma-rays. The degradation products were analysed with Gas Chromatography/Mass Spectrometer, NMR Spectrometer, Ion Chromatography and IR Spectrometer. It was found that the major radiolytic degradation products were mono-(2-ethylhexyl) phosphoric acid (MEHPA) and phosphoric acid (H3OP4) for DEHPA (DEHPA ? MEHPA ? H3PO4) and dibutyl phosphate (HDBP),monobutyl phosphate (H2MBP) and phosphoric acid for TBP (TBP ? HDBP ? H2MBP ? H3PO4), respectively.

2001-01-01

71

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

International Nuclear Information System (INIS)

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

1985-01-01

72

Change of insulation resistance and mechanical properties of polyethylene irradiated with gamma ray in hot water  

International Nuclear Information System (INIS)

[en] The evaluation of the deterioration of the polymer insulation materials of cables for nuclear facilities in radiation environment is important for heightening the safety and reliability of reactor facilities. For upgrading LWRs and extending their life, it is necessary to carry out the more detailed evaluation of radiation resistance by simulating respective environment of use of the materials used. The behavior of deterioration of insulation materials when those are used for a long period in hot water while being exposed to radiation is an interesting problem in view of clarifying the deterioration mechanism in the compound effect of water, heat and oxygen. In this research, gamma ray irradiation was carried out in hot water to polyethylene having excellent electrical properties, and the change of chemical structure and the change of electrical and mechanical properties were measured from the gel proportion and swelling, thus the effects of water, heat and oxygen were examined, and the radiation resistance in compound environment was considered. In order to cause radiation oxidation deterioration in PE without lowering dose rate, irradiation was carried out by pressurizing oxygen. 1.0 mm and 0.5 mm thick low density polyethylene sheets were used, and Co-60 gamma ray was irradiated. Tensile test was carried out. In hot water, the mechanical properties remarkably lowered. (Kako, I.)

1986-01-01

73

Study on influences of rabbit thyroids irradiated by /sup 60/Co-gamma ray  

Energy Technology Data Exchange (ETDEWEB)

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

Akiyama, A. (Nippon Dental Coll., Tokyo)

1981-02-01

74

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

International Nuclear Information System (INIS)

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

1990-01-01

75

Increased production of plumbagin in Plumbago indica root cultures by gamma ray irradiation.  

UK PubMed Central (United Kingdom)

CONTEXT: Plumbagin is a major active constituent of Plumbago indica L. (Plumbaginaceae). It possesses various pharmacological activities that have been shown to assist in the treatment of various diseases. OBJECTIVES: This work is focused on increasing the production of plumbagin in P. indica root cultures using low doses of gamma ray irradiation as an elicitor. MATERIALS AND METHODS: The effect of low doses of gamma ray irradiation (0, 5, 10, 15, 20, 25?Gy) and ages of the root cultures (0, 5, 10, 15, 20 days) for elicitation of plumbagin production was determined. The stability of the elicited root cultures to produce plumbagin was also determined during three cycles of subculture. RESULTS AND DISCUSSION: Treatment of the root cultures with a low dose of gamma ray at 20?Gy gave the highest level of plumbagin production (1.04?mg/g DW) when compared to all other treated groups. The appropriate age of the root cultures for maximum production of plumbagin was found to be 10 days. However, treatment of 5-day-old root cultures resulted in a significant increase of dried root biomass that also had a high plumbagin production. Based on the total biomass per culture flask, the amounts of plumbagin produced by the 5- and 10-day-old treated roots were 0.59 and 0.37?mg/250?mL flask, respectively, which were 4.2- and 2.6-fold higher than the level in the control. Subculturing the root cultures until the third generation still showed an increase in plumbagin production without any effects on their growth.

Jaisi A; Sakunphueak A; Panichayupakaranant P

2013-08-01

76

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

International Nuclear Information System (INIS)

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

1976-01-01

77

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

Energy Technology Data Exchange (ETDEWEB)

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 + CO{sub 2}) and organic products were analyzed by means of a TOC analyzer and gas-chromatography, respectively. It was found that chloroacetyl chloride (CH{sub 2}ClCOCl) was present as the main organic product while inorganic products (CO + CO{sub 2}) 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.)

Sun, Y.X.; Chmielewski, A.G. [Inst. of Nuclear Chemistry and Technology, Warsaw (Poland); Hakoda, T.; Hashimoto, S. [Japan Atomic Energy Research Inst. (JAERI), Takasaki Radiation Chemistry Research Establishment, Gunma (Japan)

2003-07-01

78

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

International Nuclear Information System (INIS)

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

1980-01-01

79

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)

2009-01-01

80

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

International Nuclear Information System (INIS)

The struvite crystallization was applied to remove NH4+ in livestock wastewater. The ammonium ions can be very toxic to the aquatic creatures. In this experiments, the livestock wastewater from Gongju livestock wastewater treatment plant was used. The behaviors of various parameters such as pH, mole ratio of Mg2+ : NH4+: PO43- and reaction temperature for struvite crystallization of livestock wastewater and the effect of gamma ray irradiation were evaluated. As results, for the pH variation, the NH4+ removal efficiency showed the highest, 88%, at pH 9 ? 9.25. The removal efficiency of NH4+, Mg2+ and PO43- was showed highest when same molar ratio of Mg2+ and PO43- were applied. The NH4+ removal efficiency showed 82% at 7 .deg. C, and 90% at 30 .deg. C, with temperature. When the wastewater was irradiated with 20 kGy of gamma ray, NH4+ was removed as much as 83%

2010-01-01

 
 
 
 
81

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-06-15

82

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-12-15

83

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

International Nuclear Information System (INIS)

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

2001-01-01

84

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

International Nuclear Information System (INIS)

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

1977-01-01

85

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

86

Study on shelf life extension of papayas irradiated by /sup 60/Co gamma-rays  

Energy Technology Data Exchange (ETDEWEB)

Papayas are one of the main fresh fruits in Taiwan area. Papaya fruits were treated with hot water to pasteurize peels followed by /sup 60/Co gamma-ray irradiation to extend the ripening time. The purpose of synergetic methods is to extend the shelf life of papaya fruits. This experiment was carried out by seven treatments, which were: (1) control group, (2) hot water treatment only, (3) hot water treatment with a 25 krad ..gamma..-irradiation, (4) hot water treatment with a 50 krad ..gamma..-irradiation, (5) hot water treatment with a 75 krad ..gamma..-irradiation, (6) 75 krad ..gamma..-irradiation only, and (7) hot water treatment with a 100 krad ..gamma..-irradiation. The items of observation were: surface yellowing, surface decaying, quality of texture, and length of period lasted after irradiation for 50% marketable papayas. The results of this study showed that a shelf-life extension of six days could be obtained for papayas subjected to hot water (50 to 55/sup 0/C) treatment and a 100 krad irradiation. 3 refs., 2 figs., 2 tabs.

Chang, M.S.; Chen, M.D.; Lin, C.T.; Fu, Y.K.

1984-11-01

87

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

International Nuclear Information System (INIS)

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

1994-01-01

88

Radiation damage of PbWO4 crystals due to irradiation by 60Co gamma rays  

International Nuclear Information System (INIS)

Radiation resistivity of large tungstate crystals PbWO4 from three suppliers has been studied for doses 104 Gy (106 rad) and 105 Gy (107 rad). Radiation resistivity was examined by the measurement of optical transmission through tungstate crystals before and after 60Co gamma-ray irradiations. The absolute degradation of transmission for 104 and 105 Gy doses at 480 nm wavelength of the peak emission of PbWO4 doped with La2+, was found to be lower than 12.3% and 14.2%, respectively. The results have been also compared with radiation hardness measurements for a large volume CeF3 scintillation crystal. Complete recovery of radiation damage was observed between 10 and 15 days after irradiations.

2002-01-01

89

Twenty years research of chronic gamma-ray irradiation on seed crops  

Energy Technology Data Exchange (ETDEWEB)

Twenty years of the works on the chronic gamma-ray irradiation of seed crops are summarized. Radiosensitivity and the mutation rate per unit exposure varies not only with the genetic factor but also depend on whether treatment is given to seeds or growing plants. The relation between the radiosensitivity of seeds and growing plants also varies with plant species. In Hordeum, Avena and Nicotiana, the highest mutation rate obtained by the chronic irradiation of growing plants is similar to that in seed irradiation, but in Oryza and Setalia, chronic irradiation was two to three times more effective for attaining a higher mutation rate. The mutation spectrum also varies with the mutagen, the factors modifying the effects of mutagen, and the dose of mutagen. The suitability of a particular mutagenic treatment to a species should be taken into consideration in the evaluation of mutagenic treatment. For instance, NaN/sub 3/ is highly mutagenic to barley, but less mutagenic to rice. The gene ea7 controlling the maturing earliness of barley seems to be mutable in chronic irradiation, and the mutants obtained by chronic irradiation are healthy. The author emphasized that the chronic irradiation at the gamma-field is a useful mutagenic treatment, even though some negative results have been reported in European countries.

Yamashita, Atsushi (National Inst. of Agricultural Sciences, Yatabe, Ibaraki (Japan))

1983-03-01

90

Micro-structure of gamma-ray irradiated polyethylenes studied by positron annihilation  

International Nuclear Information System (INIS)

Effects of gamma-ray irradiation on high density (HDPE) and low density (LDPE) polyethylenes were measured by positron annihilation at temperatures between 100 and 420 K. The effect of the irradiation on the intensity I3 and the lifetime ?3, of the longest lived component was significant below the glass transition temperature Tg, while they were little affected above Tg. For LDPE a marked minimum was observed in the I3 vs T curve. The lower edge of the minimum, corresponding to glass II and glass I transitions, was found to shift to lower temperatures by the irradiation. In HDPE both I3 and ?3 decreased on irradiation mainly due to radiation induced free radicals. The gel fraction of HDPE was small when irradiated below Tm, while it rose sharply on irradiation near Tm. Positron lifetime parameters of this highly crosslinked HDPE showed a distinct difference compared to HDPE irradiated below Tm. Usefulness of the positron annihilation method is discussed in conjunction with studying micro-structure of polymers. (author).

1991-01-01

91

Late effects of chronic irradiation by low dose-rate {gamma}-rays on mice  

Energy Technology Data Exchange (ETDEWEB)

To evaluate late biological effects of chronic low dose-rate radiation, mice were continuously irradiated with {gamma}-rays for 400 days after which the life span and pathological changes were evaluated. Two hundred (100 male and 100 female) specific-pathogen-free (SPF) B6C3F{sub 1} mice at six weeks of age were purchased every month. After a 2-week quarantine, they were divided into 4 groups (1 unirradiated control and 3 irradiated). Irradiation was performed using {sup 137}Cs {gamma}-rays at dose-rates of 20 mGy (22 h-day){sup -1}, 1 mGy (22 h-day){sup -1} and 0.05 mGy (22 h-day){sup -1} with equivalent accumulated doses of 8,000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until they had died a natural death. The results of the monthly microbiological examinations confirmed that the mice were maintained under SPF-conditions throughout the experimental period. A total of 4,000 mice have been admitted into the experiment since it started in February 1996, 1,000 of which were admitted during the period between July and December 1998. Data on the 20 mGy (22 h-day){sup -1} group of both sexes suggested a shortening of the life span and an increase of tumor incidence. The most common lethal neoplasmas in pooled data of unirradiated control and irradiated male mice were malignant lymphomas, hepatocellular carcinomas, lung carcinomas, and myeloid leukemias. By contrast in female mice, malignant lymphomas, myeloid leukemias, thymic lymphomas, and fibrosarcomas were common. (author)

Tanaka, Satoshi; Onodera, Junichi; Sasagawa, Sumiko; Ichinohe, Kazuaki; Otsu, Hiroshi; Sato, Fumiaki [Institute for Environmental Sciences, Department of Radiobiology, Rokkasho, Aomori (Japan)

1999-07-01

92

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

CERN Multimedia

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

93

Effect of gamma irradiation dose on the fabrication of {alpha}-elastin nanoparticles by gamma-ray crosslinking  

Energy Technology Data Exchange (ETDEWEB)

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

Fujimoto, Mari; Takeda, Mayuko [Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 (Japan); Okamoto, Kouji [Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502 (Japan); Furuta, Masakazu, E-mail: mfuruta@b.s.osakafu-u.ac.j [Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 (Japan)

2011-02-15

94

Characterization of polystyrene grafted onto nylon 6 fiber by. gamma. -ray pre-irradiation in air  

Energy Technology Data Exchange (ETDEWEB)

Molecular characterization of polystyrene grafted onto nylon 6 fiber by a {gamma}-ray pre-irradiation technique in air was performed. The molecular weight and molecular weight distribution were determined by measuring limiting viscosity number ({eta}) in m-cresol of fractions of the grafted polystyrene obtained from the nylon 6-styrene graft polymer as well as of the homopolystyrene produced in the nylon 6-styrene system. The molecular weight distribution of the grafted polystyrene was rather broad compared with that of the homopolystyrene produced by the {gamma}-ray pre-iradiation method under the same experimental conditions. Partial occurrence of H-type grafting (the propagation of a grafted chain is terminated by the reaction with another propagating grafted chain) of polystyrene onto nylon 6 fiber was suggested in the latter period of the nylon 6-styrene system, while T-type grafting (the propagation of a grafted chain is terminated by the reaction with propagation chain of homopolymer) predominated in the nylon 6-styrene/toluene system. (author).

Iwasaki, Tatsuo; Tomita, Kosuke (Unitika Ltd., Amagasaki, Hyogo (Japan))

1992-01-01

95

The preparation of functional lipid liposomes by {gamma}-ray irradiation and its application  

Energy Technology Data Exchange (ETDEWEB)

Encapsulation of the erythrocyte with polymerized phospholipid might improve the conventional erythrocyte preparations and liposome-encapsulated preparation. Therefore, production of an artificial erythrocyte was attempted using polymeric phospholipid. The behaviors of polymerization for several polymeric phospholipids following {gamma}-ray irradiation were briefly described and the previous reports on the liposome polymerization was reviewed. In addition, the membranes thus obtained were characterized by kinetic assays and LB-membrane procedures in regards to the arrangement of membrane molecules and the interactions among hydrophobic groups in the domain. The polymerization of 1,2-bis-(2,4-octadecadienoyl)-sn-glycero-3-phosphocholine (DODPC) by {gamma}-ray radiation was found superior to that by UV-radiation method. Since the generation of polymerization initiating molecule was not dependent on reaction temperature, it was possible to perform the polymerization at a low temperature, resulting that the heat denaturation of bioactive substances included into the liposome and also their leaks could be greatly repressed. (M.N.)

Hosoi, Fumio [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Akama, Kazuhiro

1997-11-01

96

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

International Nuclear Information System (INIS)

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

1996-01-01

97

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

Energy Technology Data Exchange (ETDEWEB)

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).

Sekiguchi, Masayuki; Imai, Masahiko; Tabei, Masae [Tokyo Metropolitan Isotope Research Center (Japan); Yamada, Yoshio; Shimizu, Harumichi

1995-03-01

98

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).

1995-01-01

99

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.

2011-01-01

100

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

International Nuclear Information System (INIS)

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

2008-01-01

 
 
 
 
101

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

Science.gov (United States)

The effects of gamma-ray and high energy carbon ion irradiation on the swimming velocity of the photosynthetic flagellate Euglena gracilis strain Z were studied, focusing on a dose-effect relationship. Cells were exposed to 60Co gamma-rays at 6 doses of 10, 15, 20, 40, 100 and 200 Gy for water, and also to 290 MeV/amu carbon ions from the Heavy Ion Medical Accelerator in Chiba at 7 doses (5, 10, 15, 20, 50, 100 and 200 Gy for water). The swimming velocity was measured by a biomonitoring system, called ECOTOX. The swimming velocities of Euglena gracilis cells were significantly decreased by >40 Gy gamma-rays and >5 Gy carbon ions, respectively. The 50% effective doses for inhibition, 34±4 Gy (gamma-rays) and 13±1 Gy (290 MeV/amu carbon ions), were estimated from the best fit to data of the logistic model. The relative biological effectiveness (2.6±0.4) was calculated by the ratio of 50% effective doses. The inhibition of the swimming velocity of the cells irradiated with gamma-rays was still present after 3 days, while recovery of the swimming velocity was shown in the cells exposed to 290 MeV/amu carbon ions. It is suggested that ionizing radiation inhibits ATP production and/or increases frictional drag on beating of the flagellum, thus decreasing swimming velocity.

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

102

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

103

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

104

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

International Nuclear Information System (INIS)

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.

1992-01-01

105

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

International Nuclear Information System (INIS)

[en] 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)

2009-10-02

106

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

International Nuclear Information System (INIS)

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

2002-01-01

107

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

108

Development of high yielding rice mutant variety through gamma rays irradiation  

International Nuclear Information System (INIS)

A high yielding rice mutant IR8-151 was selected from gamma rays irradiated population of a coarse (non-aromatic) rice variety IR8. The mutant IR8-151 was significantly better than its mother variety IR8 in all the yield contributing parameters except 1000 grain weight. The mutant showed promising performance for paddy yield in varietal trials. It produced the highest paddy yield per unit area in zonal trials conducted for 3 consecutive years at 10 locations with diverse agro-climatic conditions. It maintained superiority over all the entries by yielding 9196, 7976 and 8021 kg of paddy yield per hectare during the years 1989, 1990 and 1991, respectively. On the basis of over all performance, IR8-151 mutant showed an increase of 10% and 9% in paddy yield over its parent IR8 and check variety IR6, respectively. (author)

2002-01-01

109

Radiation stability test of DEHPA and TBP extractants by irradiation with cobalt-60 gamma-rays  

Energy Technology Data Exchange (ETDEWEB)

This study was carried out to evaluate the radiation stability of di-(2-ethylhexyl) phosphoric acid (DEHPA) and tributyl phosphate (TBP) extractants by irradiation with Cobalt-60 gamma-rays. The degradation products were analysed with Gas Chromatography/Mass Spectrometer, NMR Spectrometer, Ion Chromatography and IR Spectrometer. It was found that the major radiolytic degradation products were mono-(2-ethylhexyl) phosphoric acid (MEHPA) and phosphoric acid (H{sub 3}OP{sub 4}) for DEHPA (DEHPA {yields} MEHPA {yields} H{sub 3}PO{sub 4}) and dibutyl phosphate (HDBP),monobutyl phosphate (H{sub 2}MBP) and phosphoric acid for TBP (TBP {yields} HDBP {yields} H{sub 2}MBP {yields} H{sub 3}PO{sub 4}), respectively.

Yang, H. B.; Han, S. H.; Park, S. C.; Yen, J. W.; Lee, I. H. [KAERI, Taejon (Korea, Republic of)

2001-10-01

110

Irradiation of procine plasma protein powder, 2. Effect of gamma rays or electron beam irradiation on porcine plasma protein  

Energy Technology Data Exchange (ETDEWEB)

The qualies of plasma proteins irradiated with gamma rays or electorons beam were compared with those of heated and fumigated samples. The qualities of plasma proteins were evaluated in two aspects ; 1) structural changes of proteins, such as hydrophobicity, amount of SH groups and electrophoresis or gel filtration pattern, and 2) functional properties such as solubility, emulisifying activity, and fat adsorbability. Heat treatment reduced both the amount of SH groups and emulusifying activity of proteins. The HPLC gel filtration pattern of heated samples showed the high molecular peak as a results of coagulation of proteins. Fumigation caused accentuated reduction of protein of solibility, there by severly damaging their functional properties as food ingradients. Irradiation using gamma rays and electorons beam showed the same effect on the properties of proteins. Though some differences were observed with increased dose, there was no significant change in functional properties of irradiated samples. From these results, irradiation was the efficient procedure from the view points of protein quality as well as microbial decontamination.

Saito, Masayoshi; Todoroki, Setsuko; Hayashi, Toru; Tajima, Makoto; Biagio, R.

1987-11-01

111

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

International Nuclear Information System (INIS)

[en] Data on the shortening of the life span in mice by radiation show that an acute dose of gamma-rays may be as much as four times as effective as an equal dose of the same radiation administered chronically. However, for neutrons, chronic and acute administrations are equally effective. An analysis of these effects shows that for gamma-rays a certain fraction of the radiation injury is reparable, and that the value of this fraction depends on the dose and the dose rate. With neutrons, none of the damage appears reparable. For acute irradiation, the RBE is about 2 for shortening of the life span, but for chronic, may be as high as 8. Chromosome aberrations have been scored in liver cells of mice when treated with both chronic and acute doses of both gamma-rays and thermal neutrons. In all cases the percentage of aberrent cells is proportional to the shortening of the life span produced by the treatment. Further, with neutrons, acute and chronic irradiation is equally effective in producing chromosome abberations. For gamma-rays, acute irradiation may produce as much as four times the chromosomal damage as does chronic irradiation. This shows that some chromosomes can heal themselves following small doses of gamma-rays, but there is no chromosome healing following any dose of neutrons. The RBE using chromosome aberrations as a criterion is the same as for life shortening. These results give a firm cellular basis for the known biological differences between gamma rays and neutrons, and in addition give strong support to the concept that natural and radiation-induced aging are caused by spontaneous and radiation-induced mutations, respectively, in the somatic cells of animals. (author)[fr] Les données sur l ’abrègement de la durée de vie chez la souris irradiée montrent qu'une dose aiguë de rayons gamma peut être quatre fois plus efficace qu'une dose identique du même rayonnement administrée de façon chronique. Par contre, dans le cas des neutrons, les expositions chronique et aiguë ont la même efficacité. Il ressort d'une analyse de ces effets qu'une certaine fraction de la radiolésion due aux rayons gamma peut être guérie et que l'importance de cette fraction dépend de la dose et du débit de dose. Au contraire, aucune lésion provoquée par les neutrons ne semble guérissable. En ce qui concerne l'abrègement de la durée de vie, l'EBR de l'exposition aiguë est de l'ordre de 2, alors que pour l'exposition chronique elle peut atteindre la valeur 8. On a observé des altérations chromosomiques dans les cellules hépatiques de la souris, que l'animal ait été exposé à une dose chronique ou à une dose aiguë, et cela aussi bien pour les rayons gamma que pour les neutrons thermiques. Dans tous les cas, le pourcentage de cellules aberrantes est proportionnel à l'abrègement de la durée de vie dû à l ’ irradiation. En outre, le nombre des altérations produites par les neutrons reste le même, que l'exposition ait été aiguë ou chronique. Par centre, avec les rayons gamma, les dommages aux chromosomes peuvent être quatre fois plus graves après une exposition aiguë qu'après une exposition chronique. Il s'ensuromosomes peuvent guérir d'eux-mêi.ies après exposition à de faibles doses de rayons gamma, alors qu'il n’y a aucune restauration chromosomique après une irradiation par les neutrons, quelle que soit la dose reçue. Lorsqu'on prend comme critère les altérations chromosomiques, l'EBR est la même que si l'on considère l'abrègement de la durée de vie. Ces résultats fournissent une base cytologique solide pour expliquer les différences constatées entre les effets biologiques des rayons gamma et ceux des neutrons-, en outre, ils confirment nettement l'hypothèse selon laquelle le vieillissement naturel et le vieillisement radioinduit des animaux seraient provoqués respectivement par des mutations spontanées et des mutations radioinduites dans les cellules somatiques. (author)[es] Los datos sobre el acortamiento de la vida del ratón por efecto de las radiacion

1964-01-01

112

Graft copolymerization of vinyl monomers onto nylon 6 fiber by [gamma]-ray pre-irradiation in vacuum  

Energy Technology Data Exchange (ETDEWEB)

Vinyl monomers such as styrene, methyl methacrylate, acrylonitrile, and acrylamide were grafted onto nylon 6 fibers by a [gamma]-ray pre-irradiation technique in vacuum. The effect of various additives on the apparent percent graft as well as on the molecular wight and mole number of grafted vinyl polymer branch were investigated. The intrinsic viscosity [[eta

Iwasaki, Tatsuo (Nippon Ester Co., Ltd., Osaka (Japan)); Ueda, Yoshitsugu

1992-12-01

113

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 1013 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.

2007-10-01

114

An electron spin resonance study of {gamma}-ray irradiated pepper  

Energy Technology Data Exchange (ETDEWEB)

Using electron spin resonance (ESR) spectroscopy, we revealed four radical species in the irradiated pepper. The representative ESR spectrum of the pepper is composed of a sextet centered at g=2.0, a singlet at the same g-value, a singlet at g=4.0 and side peaks near g=2.0. The first one is attributable to a signal with hyperfine (hf) interactions of Mn{sup 2+} ion (hf constant=7.4 mT). The second one is due to an organic free radical that may be induced by the ({gamma}-ray irradiation. The third one may be originated from Fe{sup 3+} ion in the non-hem proteins. Those three signals were found in the pepper sample before irradiation. The fourth signals were found at the symmetric position of the organic free radical, i.e., the second signal. The progressive saturation method of the ESR microwave power indicated quite different relaxation behaviors of those radicals. The method reflects four independent radical species in the irradiated pepper. Relaxation time for the singlet signal centered at g=2.0 revealed that the signal is due to the typical organic free radical. (author)

Ukai, Mitsuko; Hamaya, Naruki; Ichii, Akane; Abe, Aika [Hokkaido Univ. of Education, Hakodate (Japan)

2003-05-01

115

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 (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.

Yoel, Ajay; Michael, Pratik E. P.; Kokate, M. V.; Tabhane, V. A.

2012-02-01

116

ESR (electron spin resonance) studies of polymer films containing leucodyes irradiated with /sup 60/Co gamma rays. Final report  

Energy Technology Data Exchange (ETDEWEB)

When plastic films containing leucocyanide of triphenylmethane dyes are irradiated with large dose of (60) Co gamma rays, free radicals are formed that are sufficiently stable for analysis at room temperature. Preliminary studies about the effect of Co-60 gamma rays on the ESR signal of radiochromic dye films are discussed, in order to investigate practicality of this technique in dosimetry. Not only can dosimetry be achieved at higher doses than are normally used with spectrophotometry of this films, but also information about the radiation chemistry of dye formation can be derived.

Uribe, R.M.; Pina, M.C.; McLaughlin, W.L.

1980-12-01

117

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)

2009-01-01

118

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

Scientific Electronic Library Online (English)

Full Text Available 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 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 (more) 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.

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

2009-01-01

119

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; JA Baptista; TL de Almeida; LAC Passos; N Nascimento

2009-01-01

120

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 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)

2009-01-01

 
 
 
 
121

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

122

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

International Nuclear Information System (INIS)

[en] 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)

1995-01-01

123

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

International Nuclear Information System (INIS)

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

2001-06-01

124

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

International Nuclear Information System (INIS)

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

2001-01-01

125

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

International Nuclear Information System (INIS)

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

1994-01-01

126

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

International Nuclear Information System (INIS)

[en] 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)

2009-10-02

127

Continuous running test of radiation resistance motor driving equipment under high gamma ray irradiation  

International Nuclear Information System (INIS)

[en] The components in the vacuum vessel of ITER (International Thermonuclear Experimental Reactor), e.g. blanket and divertor, are replaced periodically using the dedicated remote handling systems. The environment conditions inside the vacuum vessel during the operation are temperature of 50degC, air or inert gas atmosphere at 1atm gamma ray radiation; therefore multiple factors shall be considered for establishment of durability of the remote handling systems. Concerning the dose rate of gamma ray under the anticipated operation of ITER, it was evaluated 10kG/h at the early stages of ITER EDA (Engineering Design Activity), but presently it decreases down to 0.5kGy/h after detailed design and evaluation have been done. However, a continual operation for one year at the longest is planned in the remote handling systems, therefore the systems it is desired to be able to operate longer than that. According to the requirements above, JAEA (Japan Atomic Energy Agency) advanced the development of radiation resistance components, major components of approximately 55 kinds which comprise the remote handling systems and that peripheral devices, since 1995 in ITER EDA. The dose rate and the target accumulation dose for the designated radiation resistance were set 10kGy/h and 10-100MGy, respectively. On the basis of the development results, the radiation resistance motor driving equipment, which comprised parts with different radiation resistance levels, was designed simulating mechanisms of ITER remote handling systems. The motor driving equipment, the servomotor turns the weight of 8kgf (dummy load) and controls, and continuous running test under high gamma ray irradiation was lasted approximately four years from March, 2000. Irradiation conditions on the test were; the dose rate of 3.6kGy/h, the accumulation dose of 30MGy at the minimum. The data were obtained, which are acquired motor electric current, temperatures and the breakdown event under the test conditions. In addition, appearance changes of every component and deice were observed. The irradiation test was performed in two stages, which was divided by a breakdown and successive overhaul of the equipment. The achieved accumulation dose and running time in those stages were approximately 47.6MGy/13,200hours and 23.9MGy/6,640hours, respectively. As a result, it has been confirmed that sufficient radiation resistance of the equipment, which is required against a dose rate of 0.5kGy/h at least, corresponding to the atmosphere inside the vacuum vessel, was achieved. Furthermore, the causes of breakdown at the 1st and the 2nd stages are hardening of the grease lubricant filled up in the reduction gear, and deterioration of electric insulation materials of power and signal lines, respectively. In this report, we describe design conditions and basic specifications of the radiation resistance motor driving equipment, the results of the 1st and the 2nd irradiation tests and the overhaul after the 1st stage irradiation test. (author)

2006-01-01

128

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).

1989-01-01

129

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

Energy Technology Data Exchange (ETDEWEB)

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).

Akagi, Kiyoshi; Tanaka, Yoshimasa

1989-04-01

130

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

2011-01-01

131

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

International Nuclear Information System (INIS)

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

1993-01-01

132

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.)

1977-01-01

133

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

134

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

International Nuclear Information System (INIS)

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

1986-01-01

135

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

136

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

International Nuclear Information System (INIS)

[en] 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)

2002-01-01

137

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-03-01

138

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

International Nuclear Information System (INIS)

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

2010-10-01

139

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

Energy Technology Data Exchange (ETDEWEB)

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

Park, Jae Nam; Han, In Jun; Kim, Wang Geun; Song, Beom Seok; Kim, Jae Hun; Choi, Jong Il; Yoon, Yo Han; Byun, Myung Woo; Hwang, Han Joon; Lee, Ju Woon [Korea Atomic Energy Research Institte, Jeongeup (Korea, Republic of); Park, Jin Gyu [Korea University, Seoul (Korea, Republic of)

2009-06-15

140

Effects of 2. 0 Gy of /sup 60/Co gamma rays irradiation on rat embryos  

Energy Technology Data Exchange (ETDEWEB)

Pregnant rats of Donryu strain were exposed to a whole-body /sup 60/Co ..gamma.. 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 /sup 60/Co ..gamma.. ray at dose levels of 2.0 Gy on day 10 or 11 of gestation. Cases of cleft lip and cleft palate or facial cleft were observed seventeen fetuses on day 9 of gestation (31 %). Exencephaly occurred in nine embryos treated on day 9 (16.1 %) and in one embryos treated on day 10. Tail defects appeared with treatment on day 9 with the latter predominating on day 11. The present study show that maximum resorption (52.1 %) was seen with treatment on day 8 whereas the highest rate of malformation (93.3 %) was observed with treatment on day 9. (J.P.N.).

Lee, Juing-Yi; Satow, Yukio

1987-01-01

 
 
 
 
141

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

142

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

International Nuclear Information System (INIS)

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

2002-01-01

143

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

UK PubMed Central (United Kingdom)

The present work aimed at evaluating the radiolysis effect upon a set of peptides, most of them involved in physiological functions. To generate reactive radical species, a Co(60) source (up to 15 kGy) was used for controlled gamma irradiation of some peptide solutions including derivatives attaching the stable free radical Toac (2,2,6,6-tetramethypiperidine-1-oxyl-4-amino-4-carboxylic acid). Regardless of the peptide sequence, a nonlinear and progressive degradation of a total of nine peptides was detected. The results were interpreted in the light of the half-life dose (D(1/2)) parameter which represents the dose necessary for 50% peptide structure degradation. The vasoactive angiotensin II (AngII)'s analogue Ang-(1-7) showed greater stability towards gamma ray radiation than bradykinin (BK), Toac(0)-BK, Pro(4)-BK (D(1/2) around 4 and 2 kGy, respectively) which decreased to about 0.5-1.0 kGy in the case of acetyl-?-melanocyte-stimulating hormone (Ac-?-MSH) and substance P (SP). In terms of peptide structural modifications, the data acquired from different analytical methods suggested a Phe to Tyr (or its ortho and/or meta isomers) transformation as a consequence of the hydroxyl moiety insertion. Noteworthy, this effect seemed to be position-dependent as only Phe located at or near the C-terminal portion seemed to display this transformation. In contrast, Met is comparatively more easily oxidized, thus allowing to conclude that gamma irradiation may induce a complex position and/or sequence-dependent effect on peptides. As previously applied for BK, some irradiated peptides were submitted to their by-products purification, indeed a complementary target of the present approach for development of uncommon analogues for further structure-function investigation.

Vieira Rde F; Nardi DT; Nascimento N; Rosa JC; Nakaie CR

2013-01-01

144

Graft copolymerization of vinyl monomers onto nylon 6 fibers by simultaneous. gamma. -ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Vinyl monomers, such as styrene, methyl methacrylate, methyl acrylate, vinyl acetate, acrylonitrile, and acrylamide, were grafted onto nylon 6 fibers by a simultaneous {gamma}-ray irradiation technique. The effects of various additives on the apparent percent graft as well as on the molecular weight and mole number of grafted vinyl polymer branches were investigated. The molecular weight of the grafted vinyl polymer branch was determined by the limiting viscosity number of the branch polymer obtained by selective hydrolysis of the backbone nylon 6. The apparent percent graft of the grafted polystyrene increased by adding methanol, ethanol, acetic acid, or propionic acid to styrene monomer. The maximum amount of the apparent graft was obtained at the 1:1 mixture of styrene and methanol. The additive which behaved as a good swelling agent to nylon 6 and, at the same time, as a precipitant to polystyrene gave higher apparent percent graft. The apparent percent graft of vinyl monomers except vinyl acetate was increased by adding methanol or ethanol to the monomers. (author).

Iwasaki, Tatsuo; Tomita, Kosuke (Unitika Ltd., Amagasaki, Hyogo (Japan))

1991-01-01

145

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

International Nuclear Information System (INIS)

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

2011-01-01

146

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

1993-06-04

147

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

International Nuclear Information System (INIS)

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

1991-01-01

148

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

International Nuclear Information System (INIS)

[en] 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

2005-01-01

149

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-02-01

150

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

International Nuclear Information System (INIS)

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

2008-01-01

151

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

International Nuclear Information System (INIS)

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

1980-01-01

152

Study on the effect of /sup 60/Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (1)  

Energy Technology Data Exchange (ETDEWEB)

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

Kimura, H. (Osaka Univ. (Japan). School of Dentistry)

1980-12-01

153

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 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.

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

2005-09-01

154

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; Suzana G. Leitão

2005-01-01

155

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

International Nuclear Information System (INIS)

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

2001-01-01

156

Improvement of the irradiation performance of irradiators by dividing a gamma-ray source  

Energy Technology Data Exchange (ETDEWEB)

To improve the irradiation performance of vessel- and conveyor-type irradiators for efficient and uniform irradiation, a method for dividing a radiation source into two elements and putting the optimum source interval between them is proposed. With the increase in the source interval, the maximum dose rate in an irradiated material decreases slowly, while the minimum dose rate in the material and efficiency of the irradiation increase sharply and become maximum at the optimum source interval. Thereafter, the minimum dose rate decreases sharply. Consequently, the best irradiation efficiency and dose rate uniformity of the irradiation are obtained by putting the optimum interval between the source elements. The optimum source intervals and approximate formula are derived to make the optimum design of the source easy. (author).

Hoshi, Tatsuo (Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment)

1991-04-01

157

Irradiation of porcine plasma protein powder, 1. Decontamination effects of gamma rays or electrons beam on porcine plasma protein  

Energy Technology Data Exchange (ETDEWEB)

Recently interest in the use of animal blood protein as a food ingradient has been increasing. A study was conducted on the decontamination effect of gamma rays and electrons beam on plasma protein powder prepared from slaughtered porcine blood. Non irradiated sample was mainly contaminated with heat-resistant becterial spores (B. subtilis) and the total mocrobial count was 9.6 x 10/sup 3/ per 1 g of dried powder. The D/sub 10/ values of total microbial count for gamma rays and electrons beam were 0.82 kGy and 1.06 kGy, respectively. For B. subtilis, the D/sub 10/ values obtained under aerobic condition were 1.40 kGy for gamma rays and 1.45 kGy for electrons beam, with the survival curve for electrons beam showing a shoulder until 0.1 kGy. From these results, both types of irradiation were effective for the decotamination of plasma proteins.

Hayashi, Toru; Saito, Masayoshi; Todoroki, Setsuko; Tajima, Makoto; Biagio, R.

1987-11-01

158

Irradiation of Crotalus durissus terrificus crotoxin with 60Co gamma-rays induces its uptake by macrophages through scavenger receptors.  

UK PubMed Central (United Kingdom)

PURPOSE: To investigate the action of 2 kGy 60Co gamma-rays on crotoxin and its favoured uptake through scavenger receptor (ScvR) mouse peritoneal macrophages. MATERIALS AND METHODS: Native or irradiated crotoxin (iCTX) (50 microg/ml) dosed with 2 kGy 60Co gamma-rays (dose-rate 540 Gy/h) were offered to mouse peritoneal macrophages; their uptake was evaluated by immunohistochemistry and quantitative in situ ELISA. Receptors recognizing irradiated crotoxin were evaluated with specific ScvR blockers (Probucol and dextran sulphate) or with non-specific blocking using foetal calf serum (FCS). RESULTS: Immunohistochemical assays revealed more deeply staining intracytoplasmic vacuoles in macrophages incubated with iCTX. Using in situ ELISA with ScvR specific blockers, it was shown that the increased uptake of iCTX was blocked by Probucol or dextran sulphate, but not by FCS. On the other hand, the uptake of native crotoxin was decreased by FCS, but not affected by ScvR blockers. The morphology and viability of macrophages were preserved during the experiments. CONCLUSIONS: It is concluded that 60Co gamma-rays probably induced oxidative changes in crotoxin, driving this toxin towards ScvR mouse peritoneal macrophages. This suggests a different in vivo route of iCTX away from toxic neural sites by a preferential and rapid internalization and processing by macrophages, leading to the induction of a better immune response.

Cardi BA; Nascimento N; Andrade HF Jr

1998-05-01

159

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

Energy Technology Data Exchange (ETDEWEB)

Male CD/sub 2/F/sub 1//HAP mice were exposed to similar doses from Cs-137 and Cf-252 linear source arrays using a ferris wheel irradiator. The Cs-137 ..gamma..-ray dose rate was 87.2 cGy/hr as determined by TLD dosimetry. A paired ionization chamber measurement technique was utilized to evaluate the Cf-252 dose rate; i.e. 14.4 cGy/hr neutron and 6.5 cGy/hr gamma rays (n/..gamma.. ratio = 2.22). Jejunal crypt scoring criteria followed those established by a previous study. These experiments show that RBE in small bowel was high using microcolony assay. Analysis of crypt survival curves yielded a RBE for Cf-252 neutrons of approximately 6.0 for small bowel in agreement with data reported by the earlier study.

Coffey, C.W.; Meece, D.; Beach, J.L.

1986-01-01

160

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.

2005-07-25

 
 
 
 
161

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

Energy Technology Data Exchange (ETDEWEB)

Lead sulfide (PbS) nanocrystallites in the modified hyperbranched polyester matrix were prepared in situ by {sup 60}Co 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.

Zhao Yongbin [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zou Jianhua [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi Wenfang [State Key Laboratory of Fire Science and Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2005-07-25

162

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

Energy Technology Data Exchange (ETDEWEB)

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).

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

1996-03-01

163

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

Energy Technology Data Exchange (ETDEWEB)

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

Shikazono, Naoya; Hirai, Atsushi (Tokyo Univ. (Japan). Faculty of Agriculture); Watanabe, Hiroshi; Tanaka, Atsushi; Tano, Shigemitsu

1994-03-01

164

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

UK PubMed Central (United Kingdom)

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

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

1994-03-01

165

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

Science.gov (United States)

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

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

1994-03-01

166

Effect of gamma-ray irradiation on the fatty acid profile of irradiated beef meat.  

Science.gov (United States)

The effect of ?-ray irradiation on the fatty acid profile of beef meat was examined at doses of 2.5, 5.0, 7.5, 10.0 and 15.0kGy by means of (1)H NMR spectroscopy. NMR results revealed a clear trend toward an increase in the amount of saturated fatty acids and a decrease in the amount of polyunsaturated fatty acids in the triacylglycerol composition of the irradiated samples compared to the unirradiated sample with increasing the irradiation dose. The observed changes in the fatty acid profile were confirmed by gas chromatography analysis of the samples irradiated at doses of 7.5, 10.0 and 15.0kGy. PMID:23140687

Stefanova, Rayna; Toshkov, Stoyan; Vasilev, Nikola V; Vassilev, Nikolay G; Marekov, Ilko N

2011-01-09

167

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

International Nuclear Information System (INIS)

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

1986-01-01

168

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

Energy Technology Data Exchange (ETDEWEB)

Total aerobic bacteria in spices used in this study were determined to be 1 x 10{sup 6} to 6 x 10{sup 7} per gram. A study on the inactivation of microorganisms in spices showed that doses of 6-9 kGy of EB (electron-beams) or {gamma}-irradiation were required to reduce the total aerobic bacteria to below 10{sup 3} per gram. However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These differences of radiation sensitivities between EB and {gamma}-rays was explained by dose rate effect on oxidation damage to microorganisms from the results of radiation sensitivities of Bacillus pumilus and B. megaterium spores at dry conditions. On the other hand, these high dose rate of EB irradiation suppressed the increase of peroxide values in spices at high dose irradiation up to 80 kGy. However, components of essential oils in spices were not changed even irradiated up to 50 kGy with EB and {gamma}-rays. (author).

Ito, Hitoshi; Islam, Md.S. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1994-06-01

169

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

International Nuclear Information System (INIS)

[en] 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)

2008-01-01

170

Accumulation and dissipation of positive charges induced on a PMMA build-up cap of an ionisation chamber by 60Co gamma-ray irradiation  

International Nuclear Information System (INIS)

The signal current from an ionisation chamber with a PMMA build-up cap decreases with irradiation time due to electric fields produced by positive charges induced on the cap. In the present study, it was confirmed that the signal current decreases faster for irradiation using narrower 60Co gamma-ray beams. This is because the number of secondary electrons that are emitted from surrounding materials and penetrate the build-up cap is smaller in a narrower gamma-ray beam, so that fewer positive charges are neutralised. The ionisation chamber was first subjected to continuous gamma-ray irradiation for 24 h, following which it was irradiated with shorter periodic gamma-ray bursts while measuring the current signal. This allowed the coefficients of positive charge accumulation and dissipation to be determined. It was found that the dissipation coefficient has a large constant value during gamma-ray irradiation and decreases asymptotically to a small value after irradiation is stopped. From the coefficients, the minimum signal current was calculated, which is the value when accumulation and dissipation balance each other under continuous irradiation. The time required for the signal current to recover following irradiation was also calculated. (authors)

2013-01-01

171

Fractionated Irradiation of Mice with Fission Neutrons and Co60 Gamma Rays  

International Nuclear Information System (INIS)

[en] This paper deals with the comparative effects of fission neutrons and Co60 gamma-rays, delivered at low dose rates over a 13-week period, on survival in CF No. 1 female mice. Animals were exposed in the gamma-neutron chamber at Argonne's CP-5 research reactor. The dose rate was approximately 0.75 rad/min for the neutrons and 0.25 rad/min for the gamma-rays. Fractionation of the weekly neutron dose into one, three, or six doses did not appear to have a significant effect on the mean survival times of the irradiated mice. Thymic tumours were observed in at least 90% of the mice that died following these fractionated exposures to either neutrons or gamma-rays. The RBE (n/?) for these 13-week exposures at low dose rates appears to resemble the acute RBE (2.8) rather than the higher value (5 to 15) reported when mice are exposed for the length of their lives to small daily doses. (author)[fr] Le mémoire étudie les effets comparés des neutrons de fission et des rayons gamma de 60Co délivrés à de faibles débits de dose, au cours d'une période de 13 semaines, sur la survie de souris femelles CF.l. Les animaux ont été exposés dans la chambre gamma-neutrons du réacteur de recherche CP-5 d’Argonne. Le débit de dose était d’environ 0, 75 rad/min pour les neutrons et 0,25 rad/min pour les rayons gamma. Le fractionnement de la dose hebdomadaire de neutrons en trois ou six expositions ne semble pas avoir eu d'effet significatif sur le temps de survie moyen des souris irradiées. On a observé des tumeurs du thymus chez au moins 90% des souris qui mouraient à la suite de ces expositions à des doses fractionnées de neutrons ou de rayons gamma. L’EBR (n/?) pour ces expositions pendant 13 semaines à de faibles débits de dose est plutôt comparable à l'EBR de doses intenses (2, 8) qu’aux valeurs plus élevées (5 à 15) qui ont été indiquées lorsque les souris sont exposées pendant toute leur vie à de faibles doses quotidiennes. (author)[es] Los autores comparan el efecto de los neutrones de fisión y los rayos gamma de 60Co, aplicados con baja intensidad de dosis durante un período de 13 semanas, sobre la supervivencia de hembras de ratón de la raza CF Ns 1. La exposición se realizó en la cámara gamma-neutrónica del reactor de investigación CP-5 del Laboratorio de Argonne. Las intensidades de lal orden de 0,75 rad/min para los neutrones y 0,25 rad/min para los rayos gamma. Al parecer, el fraccionamiento de la dosis neutrónica semanal en series de 1,3 ó 6 dosis no influyó significativamente sobre el tiempo medio de supervivencia de los ratones Irradiados. Se observaron tumores del timo por lo menos en el 90 por ciento de los ratones muertos a consecuencia de estas exposiciones fraccionadas, sea a neutrones o a rayos gamma. La EBR (n/?) para estas exposiciones de 13 semanas con pequeñas intensidades de dosis se aproxima aparentemente más a la EBR aguda (2, 8) que a los valores mayores (5 a 15 ) comunicados en los casos en que los ratones quedan expuestos durante toda su vida a pequeñas dosis diarias. (author)[ru] Sravnivaetsja vlijanie nejtronov delenija i gamma-luchej So60 s nizkoj moshhnost'ju doz v techenie 13 nedel' na vyzhivanie samok myshej linii CF N = 1. Zhivotnyh obluchali v gamma-nejtronnoj kamere argonnskogo reaktora SR-5. Moshhnost' dozy ravnjalas' priblizitel'no 0,75 rad/min dlja nejtronov i 0,25 rad/min dlja gamma-luchej. Frakcionirovanie nedel'noj dozy nejtronov na 1, 3 ili 6 doz, kazalos', ne okazyvalo znachitel'nogo jeffekta na srednie sroki vyzhivanija obluchennyh myshej. Opuholi zobnoj zhelezy byli obna- ruzheny, po krajnej mere, u 90% myshej, pogibshih posle takogo frakcionirovannogo nejtronnogo ili gamma-obluchenija. OBJe (n/?) pri 13-nedel'nom obluchenii i nizkoj moshhnosti doz skoree priblizhaetsja k OBJe pri ostrom obluchenii (2,7), chem k bolee vysokim velichinam (5 — 15) , kogda myshej obluchajut v techenie vsego sroka zhizni ezhednevno malymi dozami. (author)

1964-01-01

172

Genetic improvement of soybean seed proteins by {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Although soybeans have the highest protein content among seed crops, the protein quality is poor due to the low content of the sulfur-containing amino acids, cysteine and methionine. Soybean 7S globulin and 11S globulin are the two major protein components, accounting for about 70% of the total seed protein. The 11S globulin contains three to four times more methionine and cysteine per unit protein than that of the 7S globulin. Furthermore, the two globulins show considerable differences in food processing properties such as gel-making ability and emulsifying capacity. The 7S globulin is composed of three kinds of polypeptides, designated as {alpha}, {alpha}` and {beta} subunits. A variety of soybean cv. Keburi, which lacks {alpha}` subunit was identified in a germplasm collection. An induced mutant line which lacks both {alpha} and {alpha}` subunits, was recently identified in the progeny of {gamma}-ray-irradiated seeds from a line lacking {alpha}` subunit. On the other hand, the 11S globulin is composed of the A{sub 1a}B{sub 2}, A{sub 1b}B{sub 1b}, A{sub 2}B{sub 1a}, A{sub 3}B{sub 4} and A{sub 4}A{sub 5}B{sub 3} subunits. It has become possible to breed soybeans with markedly modified protein composition from extremely high to extremely low 7S : 11S ratios using mutant genes for the subunits of the two globulins. Lipoxygenase catalyzes the hydroperoxydation of unsaturated fatty acids and polyunsaturated lipids. Soybean seeds contain three lipoxygenase isozymes, called L-1, L-2 and L-3, which are responsible for the generation of grassy-beany and bitter tastes, limiting the use of whole soybeans and soy proteins in certain food products. In the early 1980s, three types of spontaneous mutant soybean varieties lacking L-1, L-2 or L-3 were detected. Soybean cultivars having the lipoxygenase-null traits could become economically valuable for the manufacture of soy products such as soy milk due to their low levels of beany taste and their enhanced storage stability. (J.P.N.)

Kitamura, Keisuke [Agriculture, Forestry and Fisheries Research Council Secretariat, MAFF, Research and Development Division (Japan)

1998-12-31

173

Accurate measurement of doses in the sample chamber of a {sup 137}Cs{gamma}-ray irradiation apparatus  

Energy Technology Data Exchange (ETDEWEB)

Dose rates in the sample chamber of a {sup 137}Cs{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%. (author)

Abe, Toshiaki; Yamamoto, Hisao [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan). Radioisotope Research Center; Norimura, Toshiyuki

1999-12-01

174

[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

175

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

UK PubMed Central (United Kingdom)

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%.

Abe T; Yamamoto H; Norimura T

1999-12-01

176

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

Energy Technology Data Exchange (ETDEWEB)

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

Legave, J.M.; Garcia, G.

1988-01-01

177

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

International Nuclear Information System (INIS)

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

2000-01-01

178

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

International Nuclear Information System (INIS)

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.

2003-01-01

179

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.; Pejovi? Svetlana M.; Doli?anin Edin ?.; Lazarevi? ?or?e

2011-01-01

180

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

International Nuclear Information System (INIS)

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

2011-01-01

 
 
 
 
181

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

International Nuclear Information System (INIS)

[en] 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)

1998-01-01

182

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

International Nuclear Information System (INIS)

[en] 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)

2003-01-01

183

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)

2007-01-01

184

Identification of gamma-ray irradiated medicinal herbs using pulsed photostimulated luminescence, thermoluminescence, and electron spin resonance spectroscopy.  

Science.gov (United States)

Dried herbal samples consisting of root, rhizome, cortex, fruit, peel, flower, spike, ramulus, folium, and whole plant of 20 different medicinal herbs were investigated using pulsed photostimulated luminescence (PPSL), thermoluminescence (TL), and electron spin resonance spectroscopy (ESR) to identify gamma-ray irradiation treatment. Samples were irradiated at 0-50 kGy using a 60Co irradiator. PPSL measurement was applied as a rapid screening method. Control samples of 19 different herbs had photon counts less than the lower threshold value (700 counts 60 s(-1)). The photon counts of non-irradiated clematidis radix and irradiated evodia and gardenia fruits were between the lower and upper threshold values (700-5,000 counts 60 s(-1)). TL ratios, i.e., integrated areas of the first glow (TL1)/the second glow (TL2), were found to be less than 0.1 in all non-irradiated samples and higher than 0.1 in irradiated ones providing definite proof of radiation treatment. ESR spectroscopy was applied as an alternative rapid method. In most of the irradiated samples, mainly radiation-induced cellulosic, sugar, and relatively complicated carbohydrate radical ESR signals were detected. No radiation-specific ESR signal, except one intense singlet, was observed for irradiated scrophularia and scutellaria root and artemisiae argyi folium. PMID:19529925

Pal, Sukdeb; Kim, Byeong Keun; Kim, Won Young; Kim, Min Jung; Ki, Hyeon A; Lee, Kyeong-Hee; Kang, Woo Suk; Kang, In Ho; Kang, Shin Jung; Song, Joon Myong

2009-06-16

185

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-03-15

186

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

International Nuclear Information System (INIS)

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

2011-01-01

187

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-09-01

188

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

International Nuclear Information System (INIS)

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

2008-01-01

189

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

International Nuclear Information System (INIS)

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

2012-01-01

190

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

191

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

2003-01-01

192

Freshly induced short-lived gamma-ray activity as a measure of fission rates in lightly re-irradiated spent fuel  

International Nuclear Information System (INIS)

[en] A new measurement technique has been developed to determine fission rates in burnt fuel, following re-irradiation in a zero-power research reactor. The development has been made in the frame of the LIFE-PROTEUS program at the Paul Scherrer Institute, which aims at characterizing the interfaces between fresh and highly burnt fuel assemblies in modern LWRs. To discriminate against the high intrinsic gamma-ray activity of the burnt fuel, the proposed measurement technique uses high-energy gamma-rays, above 2000 keV, emitted by short-lived fission products freshly produced in the fuel. To demonstrate the feasibility of this technique, a fresh UO2 sample and a 36 GWd/t burnt UO2 sample were irradiated in the PROTEUS reactor and their gamma-ray activities were recorded directly after irradiation. For both fresh and the burnt fuel samples, relative fission rates were derived for different core positions, based on the short-lived 142La (2542 keV), 89Rb (2570 keV), 138Cs (2640 keV) and 95Y (3576 keV) gamma-ray lines. Uncertainties on the inter-position fission rate ratios were mainly due to the uncertainties on the net-area of the gamma-ray peaks and were about 1-3% for the fresh sample, and 3-6% for the burnt one. Thus, for the first time, it has been shown that the short-lived gamma-ray activity, induced in burnt fuel by irradiation in a zero-power reactor, can be used as a quantitative measure of the fission rate. For both fresh and burnt fuel, the measured results agreed, within the uncertainties, with Monte Carlo (MCNPX) predictions.

2010-12-01

193

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-09-15

194

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1986-06-01

195

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

International Nuclear Information System (INIS)

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

1986-01-01

196

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

Science.gov (United States)

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

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

2005-03-01

197

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; Jinhua Zou

2012-01-01

198

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)

1998-01-01

199

Effects of the gamma-ray irradiation on the optical absorption of pure silica core single-mode fibres in the visible and NIR range  

International Nuclear Information System (INIS)

Optical absorption induced by photon radiation was evaluated for several commercial pure silica core, single mode, optical fibres. The study was performed for three different wavelengths: 630, 670 and 785 nm. We have identified a fibre whose induced transmission loss stays below 1 dB/m after 300 kGy gamma-ray irradiation.

2005-02-11

200

Post-irradiation grafting of tetrafluoroethylene at low temperatures. [Gamma rays  

Energy Technology Data Exchange (ETDEWEB)

Low-temperature postirradiation grafting of tetrafluoroethylene (TFE) to polyolefines and silicone elastomers was the subject of study. After preliminary dissolution of TFE in the polymer at 273/sup 0/K the system was slowly cooled to 77/sup 0/K. In this process a certain part of TFE in polyolefines (ethylene-propylene copolymer and polypropylene) is retained by the vitreous polymer matrix. When slowly heated after radiolysis at 77/sup 0/K this system shows graft polymerization of dissolved TFE after T/sub g/. The graft copolymer is soluble and its IR spectra contain absorption bands characteristic of polytetrafluoroethylene. In polydimethylsiloxane rubber (SKT) the dissolved TFE when frozen to 77/sup 0/K remains sorbed between the SKT crystallites rather than in a separate phase. When those radiolyzed samples are heated the graft-polymerization occurs primarily over the temperature range between the TFE and SKT melting points. The technique provides for 100 to 150% grafting of TFE. This method also permits grafting to silicone rubbers and to several other polymers and elastomers.

Barkalov, I.M.; Kiryukhin, D.P.; Muydinov, M.R.

1981-09-01

 
 
 
 
201

Thermal behavior of organic free radicals in {gamma}-ray irradiated pepper studied by electron spin resonance spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

Using electron spin resonance (ESR) spectroscopy, we revealed heating effects on irradiated pepper. The representative ESR spectrum of the irradiated pepper is consisted of four components a sextet centered at g=2.0, a singlet at the same g-value, a singlet at g=4.0 and side peaks near g=2.0. The first one is attributable to a signal with hyperfine (hf) interactions of Mn{sup 2+} (hf constant=7.4 mT). The second one is due to an organic free radical that is induced by the {gamma}-ray irradiation. The third one may originated from Fe{sup 3+} in the nonhem proteins. The fourth signal was found at the symmetric positions of the organic free radical, i.e., the second signal. Upon heating, the forth signals decreased monotonicaly. The ESR signal of the pepper heated for more than 10 min was essentially the same as that before the irradiation. On the other hand, the second signal increased and then leveled off at a constant value by further heating. This is indicative the occurrence of some biochemical reactions such as Maillard reaction during heating procedures. (author)

Ichii, Akane; Abe, Aika; Ukai, Mitsuko [Hokkaido Univ. of Education, Hakodate (Japan)

2003-04-01

202

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

International Nuclear Information System (INIS)

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

2004-01-01

203

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)

[en] 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)

2011-01-01

204

New rice variety, DT38 selected successfully by gamma rays irradiation  

International Nuclear Information System (INIS)

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

2008-01-01

205

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.)

2000-01-01

206

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

International Nuclear Information System (INIS)

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

2007-01-01

207

Early ultrastructural lesions of apoptotic thymocytes after a whole-body-irradiation of adult mice by 137-cesium gamma rays  

International Nuclear Information System (INIS)

Three groups of adult female mice (S.w.), were exposed whole-body irradiation of 137-Cesium gamma rays at 2, 4, and 6 Gy/mn). For all groups, samples were taken at 2, 6, and 24 hours after irradiation and immediately fixed in a 1.4 % solution of glutaraldehyde containing 0.1 M sodium cacodylate buffer. Specimens were post-fixed in 1 % osmium tetroxide in the same buffer, then dehydrated in ethanol and 1, 2-epoxy-propane, impregnated in a mixture of propylene oxide and epon before being embedded in pure epon and polymerized at 60 deg C during 24 hours. Using a diamond knife and an ultra-microtome, ultrathin sections of approximately 50 nm thick were cut and deposited on copper grids. The sections were stained with uranyl acetate and lead citrate and studied with the electron microscopy (Philips 300). Early ultrastructural lesions were characterized by condensation of chromatin, convolution and fragmentation of nuclei. Clarification of cytoplasm and mitochondrial alterations were observed in a number of thymocytes depending on the radiation dose although the ultrastructure of the other ones remains normal. These lesions increased according to the length of the post-irradiation period. Clarifications of the cytoplasm with important mitochondrial lesions, as well as modifications of the cytoplasmic membrane were observed 24 hours after irradiation at 2 Gy and a number of polymorphonuclear cells and macrophages were observed in the thymus. Most often a single macrophage contains several apoptotic thymocytes, up to eight. The same alterations were observed in the other irradiated groups, but the extent of damage was much more important. In an other experimentation at 6 Gy the earliest ultrastructural lesions of apoptosis have been observed 15 minutes after the irradiation. (authors)

1997-01-01

208

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

International Nuclear Information System (INIS)

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

1989-01-01

209

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

International Nuclear Information System (INIS)

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

1992-01-01

210

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

International Nuclear Information System (INIS)

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

1996-01-01

211

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

International Nuclear Information System (INIS)

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

1996-01-01

212

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%.

1975-01-01

213

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

International Nuclear Information System (INIS)

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

1993-01-01

214

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

International Nuclear Information System (INIS)

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

2002-01-01

215

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

International Nuclear Information System (INIS)

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

2002-01-01

216

Increase of intracellular glutathione by low-dose gamma-ray irradiation is mediated by transcription factor AP-1 in RAW 264.7 cells.  

UK PubMed Central (United Kingdom)

The mechanism of the elevation of intracellular glutathione induced by low-dose gamma-rays was examined in RAW 264.7 cells. The expression of mRNA for gamma-glutamylcysteine synthetase (gamma-GCS) increased soon after gamma-ray (0.5 Gy) irradiation, and peaked between 3 h and 6 h post-irradiation. A dose of 0.25 to 0.5 Gy was optimum for induction of gamma-GCS mRNA expression at 3 h post-irradiation. The effect of inhibitors of activator protein-1 (AP-1) and nuclear factor kappaB (NF-kappaB) on the radiation-induced gamma-GCS gene expression was then examined. The induction of gamma-GCS mRNA expression was significantly suppressed when AP-1 DNA binding, but not NF-kappaB DNA binding, was inhibited. Finally, electrophoretic mobility shift assay showed that the low-dose radiation markedly increased the DNA binding of AP-1, but not NF-kappaB, soon after irradiation. These results suggest that the increase of glutathione levels in RAW 264.7 cells by low-dose gamma-ray irradiation is mediated by transcriptional regulation of the gamma-GCS gene, predominantly through the AP-1 binding site in its promoter.

Kawakita Y; Ikekita M; Kurozumi R; Kojima S

2003-01-01

217

Increase of intracellular glutathione by low-dose {gamma}-ray irradiation is mediated by transcription factor AP-1 in raw 264.7 cells  

Energy Technology Data Exchange (ETDEWEB)

The mechanism of the elevation of intracellular glutathione induced by low-dose {gamma}-rays was examined in RAW 264.7 cells. The expression of mRNA for {gamma}-glutamylcysteine synthetase ({gamma}-GCS) increased soon after {gamma}-ray (0.5 Gy) irradiation, and peaked between 3 h and 6 h post-irradiation. A dose of 0.25 to 0.5 Gy was optimum for induction of {gamma}-GCS mRNA expression at 3 h post-irradiation. The effect of inhibitors of activator protein-1 (AP-1) and nuclear factor {kappa}B (NF-{kappa}B) on the radiation-induced {gamma}-GCS gene expression was then examined. The induction of {gamma}-GCS mRNA expression was significantly suppressed when AP-1 DNA binding, but not NF-{kappa}B DNA binding, was inhibited. Finally, electrophoretic mobility shift assay showed that the low-dose radiation markedly increased the DNA binding of AP-1, but not NF-{kappa}B, soon after irradiation. These results suggest that the increase of glutathione levels in RAW 264.7 cells by low-dose {gamma}-ray irradiation is mediated by transcriptional regulation of the {gamma}-GCS gene, predominantly through the AP-1 binding site in its promoter. (author)

Kawakita, Yasunori; Kurozumi, Risa; Kojima, Shuji [Tokyo Univ. of Science, Noda, Chiba (Japan). Faculty of Pharmaceutical Sciences; Ikekita, Masahiko [Tokyo Univ. of Science, Noda, Chiba (Japan). Faculty of Science and Technology

2003-01-01

218

Increase of intracellular glutathione by low-dose gamma-ray irradiation is mediated by transcription factor AP-1 in RAW 264.7 cells.  

Science.gov (United States)

The mechanism of the elevation of intracellular glutathione induced by low-dose gamma-rays was examined in RAW 264.7 cells. The expression of mRNA for gamma-glutamylcysteine synthetase (gamma-GCS) increased soon after gamma-ray (0.5 Gy) irradiation, and peaked between 3 h and 6 h post-irradiation. A dose of 0.25 to 0.5 Gy was optimum for induction of gamma-GCS mRNA expression at 3 h post-irradiation. The effect of inhibitors of activator protein-1 (AP-1) and nuclear factor kappaB (NF-kappaB) on the radiation-induced gamma-GCS gene expression was then examined. The induction of gamma-GCS mRNA expression was significantly suppressed when AP-1 DNA binding, but not NF-kappaB DNA binding, was inhibited. Finally, electrophoretic mobility shift assay showed that the low-dose radiation markedly increased the DNA binding of AP-1, but not NF-kappaB, soon after irradiation. These results suggest that the increase of glutathione levels in RAW 264.7 cells by low-dose gamma-ray irradiation is mediated by transcriptional regulation of the gamma-GCS gene, predominantly through the AP-1 binding site in its promoter. PMID:12520165

Kawakita, Yasunori; Ikekita, Masahiko; Kurozumi, Risa; Kojima, Shuji

2003-01-01

219

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

Directory of Open Access Journals (Sweden)

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

Bassam Alfeeli; Gary Pickrell; Marc A. Garland; Anbo Wang

2007-01-01

220

Effect of gamma rays on the populations of irradiated varieties and hybrids in Sesame  

International Nuclear Information System (INIS)

Six varieties and nine hybrids of sesame were subjected to gamma irradiation. The effect of irradiation on the populations of irradiated varieties and hybrids was studied in second and third generations. In general, irradiation of hybrids and varieties produced more or less similar pattern of deviations in the population mean with negative shift for most of the characters studied. Non-alteration of population mean for plant height and 1000 seed weight was observed in the M2 and M3. In F2M2 and F3M3 generations, the 1000 seed weight remained unaltered. Most of the other characters which showed negative shift in F2M2 recorded non-alteration in F3M3. (author)

1997-01-01

 
 
 
 
221

Study on morphological changes of ovaries in mice exposed to /sup 60/Co gamma ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

The female mice aged 6 to 7 weeks were exposed to a single dose of 400 R irradiation and the morphological changes of their ovaries were observed until the seventh week after irradiation. In the early period after irradiation the primary follicle had disappeared and the other matured follicles were degenerated to turn into atretic follicles at 5 weeks after irradiation. The theca interna cells of the atretic follicles were proliferated and mixed with the surrounding interstitial cells. Any morphological differences could not be discerned between the theca interna cells and the interstitial cells. Both of them were identified as a cell of steroid hormone producing type. Therefore it was suggested that the theca interna cells of the atretic follicle transformed into the interstitial cells.

Nishida, T. (Kurume Univ., Fukuoka (Japan). School of Medicine)

1980-12-01

222

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

International Nuclear Information System (INIS)

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

2007-01-01

223

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1980-09-01

224

Roentgenographic observation on development and formation of the teeth irradiated by 60Co-gamma ray  

International Nuclear Information System (INIS)

On a 4-year-old boy who received radiotherapy for malignant tumor in his right mandibula, development of the teeth of 3rd to the 7th in the upper left side and the 3rd to the 7th in the upper right side was observed for 8 years. In the teeth of the 3rd to the 7th in the upper left side which were in irradiated field, and the teeth, except for the teeth of the 3rd to the 6th in the upper left side which had already completed development before irradiation, showed remarkable abnormalities in the shape of the crown such as atrophy, dwarfishness, and flatness. Also the teeth of the 3rd to the 7th of the upper right side which were not in irradiated field, teeth except for the those of the 3rd to the 6th in the upper right side showed slight abnormality in the shape of the crown and root. In irradiated teeth of the 3rd to the 7th in the upper left side, development and formation of teeth were remarkably interfered so that the teeth were almost rootless. In non-irradiated teeth of the 3rd to the 7th in the upper right side atrophy, dwarfishness, and hypoplasia in width and in diameter too. In irradiated teeth of the 3rd to the 7th in the upper left side, calcification was highly advanced in comparison with that in non-irradiated teeth of the 3rd to the 7th in the upper right side or that in normal upper right side. Also in non-irradiated teeth of the 3rd in the 7th in the upper right side, calcification was slightly advanced compared with that in normal teeth. In irradiated teeth of the 3rd to the 7th in the upper left side, the eruption of the teeth was remarkably facilitated. The irradiated tooth of the 6th in the upper left side fell out early and the other teeth were seen in planted condition on the mandibula. This seemed to be due to the foreign body eliminating mechanism. (Ueda, J.)

1978-01-01

225

Improving the surface properties of multi-walled carbon nanotubes after irradiation with gamma rays  

International Nuclear Information System (INIS)

The effects of gamma-irradiation on the modification of the surface and structure of multi-walled carbon nanotubes were studied. Gamma-irradiation affected the graphitization properties of functional groups, and decreased the diameter of multi-walled carbon nanotubes. The irradiated multi-walled carbon nanotubes with the absorbed dose of 100 kGy exhibited a larger specific surface area and microporous volume as compared with the other samples. The Raman spectroscopy and X-ray photoelectron spectroscopy showed that the interaction between the gamma-irradiation and the multi-walled carbon nanotubes with the absorbed dose of 150 kGy destroyed the nanostructure of carbons, leading to the formation of diamond-like structures and carbon oxides. In addition, gamma-irradiation with the absorbed dose of 100 kGy improved multi-walled carbon nanotubes graphitization and surface properties while at higher absorbed dose (150 kGy), it induced damaged structures (sp3 bonds and oxygen compositions).

2011-11-01

226

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

227

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

International Nuclear Information System (INIS)

[en] 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

1997-01-01

228

Improving the surface properties of multi-walled carbon nanotubes after irradiation with gamma rays  

Energy Technology Data Exchange (ETDEWEB)

The effects of gamma-irradiation on the modification of the surface and structure of multi-walled carbon nanotubes were studied. Gamma-irradiation affected the graphitization properties of functional groups, and decreased the diameter of multi-walled carbon nanotubes. The irradiated multi-walled carbon nanotubes with the absorbed dose of 100 kGy exhibited a larger specific surface area and microporous volume as compared with the other samples. The Raman spectroscopy and X-ray photoelectron spectroscopy showed that the interaction between the gamma-irradiation and the multi-walled carbon nanotubes with the absorbed dose of 150 kGy destroyed the nanostructure of carbons, leading to the formation of diamond-like structures and carbon oxides. In addition, gamma-irradiation with the absorbed dose of 100 kGy improved multi-walled carbon nanotubes graphitization and surface properties while at higher absorbed dose (150 kGy), it induced damaged structures (sp{sup 3} bonds and oxygen compositions).

Safibonab, B. [Plasma Physics Research Center, Sciences and Researches Campus, Islamic Azad University, P.O. Box: 14515-574, Tehran (Iran, Islamic Republic of); Material Research School, P.O. Box: 14395-836, Tehran (Iran, Islamic Republic of); Reyhani, A. [Material Research School, P.O. Box: 14395-836, Tehran (Iran, Islamic Republic of); Nozad Golikand, A., E-mail: a.nozad.golikand@gmail.com [Material Research School, P.O. Box: 14395-836, Tehran (Iran, Islamic Republic of); Mortazavi, S.Z.; Mirershadi, S. [Material Research School, P.O. Box: 14395-836, Tehran (Iran, Islamic Republic of); Ghoranneviss, M. [Plasma Physics Research Center, Sciences and Researches Campus, Islamic Azad University, P.O. Box: 14515-574, Tehran (Iran, Islamic Republic of)

2011-11-01

229

Growth evaluation of avocado selections irradiated with gamma rays Co 60  

International Nuclear Information System (INIS)

[en] 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)

1992-01-01

230

Flashover characteristics of poloidal field coils under gamma-ray irradiation  

International Nuclear Information System (INIS)

[en] 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)

1979-01-01

231

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)

2010-01-01

232

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

International Nuclear Information System (INIS)

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

1992-01-01

233

Graft copolymerization of vinyl monomers onto nylon 6 fibers by. gamma. -ray pre-irradiation in air  

Energy Technology Data Exchange (ETDEWEB)

Vinyl acetate, methyl methacrylate, alkyl acrylates, acrylonitrile, and acrylamide, were grafted onto nylon 6 fibers by the {gamma}-ray pre-irradiation technique, and the effects of grafting on the microstructure and the mechanical properties of the graft copolymers were investigated. According to the analysis by wide-angle X-ray diffraction, the degree of crystallization decreased by increasing the percent graft of poly(vinyl acetate) in the grafted nylon 6 films. The mechanical parameters, such as the Young's modulus and the tensile strength at break, increased with increasing percent graft up to 50%. When percent grafting was smaller than 50%, rather homogeneous amorphous materials were obtained with vinyl acetate, while heterogeneous ones were obtained with other vinyl monomers. A poly(vinyl alcohol) grafted nylon 6 was obtained effectively by saponification of poly(vinyl acetate) grafted nylon 6, the former showing higher mechanical properties than the latter. Similar behavior was observed after saponification of the poly(methyl acrylate) grafted nylon 6. (author).

Iwasaki, Tatsuo; Ueda, Yoshitsugu (Unitika Ltd., Amagasaki, Hyogo (Japan))

1992-07-01

234

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

International Nuclear Information System (INIS)

[en] '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)

235

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

International Nuclear Information System (INIS)

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

2004-01-01

236

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

237

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

International Nuclear Information System (INIS)

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

2007-01-01

238

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)

[en] 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

1989-01-01

239

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

240

Radio-sterilization of medical products, 9. Studies on migration of plasticizer from blood tubing irradiated by gamma-ray of /sup 60/Co  

Energy Technology Data Exchange (ETDEWEB)

The effect of ..gamma..-ray sterilization on the amount of di(2-ethylhexyl) phthalate (DEHP) eluted from blood tubing of hemodialysis to human serum was studied. The tubings were irradiated by ..gamma..-ray of /sup 60/Co at 1.5 and 2.5 Mrad. Three hundred mililiter of human serum was circulated in the tubing for 6 hr, and the amount of DEHP eluted into the human serum was determined periodically by HPLC method. Consequently, the amount of DEHP eluted from irradiated tubings was almost the same as unirradiated tubings. However, after 4 and 15 months of storage, the former was more than the latter by 30-40%. Elution of DEHP from bilayer type tubing (inner; coplymer of ethylene and vinylacetate, outer; poly(vinylchloride)) was less than commercial PVC tubings. Mono(2-ethylhexyl) phthalate (MEHP), a hydrolysed product of DEHP, could not be detected in human serum circulated in the tubings.

Tsuji, Kusuo; Shintani, Hideharu; Kikuchi, Hiroshi; Oba, Takuma; Koshimura, Einosuke (National Inst. of Hygienic Sciences, Tokyo (Japan))

1983-10-01

 
 
 
 
241

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

242

[Changes in fructosediphosphate aldolase and glucose-6-phosphate dehydrogenase activity after irradiation of animals with an absolute lethal dose of gamma rays  

UK PubMed Central (United Kingdom)

A single total-body exposure of rats to gamma-rays in an absolutely lethal dose caused significant changes in the activity of fructosodiphosphate aldolase (ALD) and glucose-6-phosphate dehydrogenase (G-6-PDH) in the brain, liver, myocardium and skeletal muscles. The activity of ALD was mainly inhibited and that of G-6-PDH increased. Thus, the initial step of glycolysis was significantly inhibited and the key reaction of the pentose phosphate pathway enhanced in the irradiated body.

Savitski? IV; Musi?ko VA; Erigova SG

1985-03-01

243

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).

1993-01-01

244

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.

2006-01-01

245

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)

1989-01-01

246

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

247

Effect of 60Co gamma-ray irradiation on dilute aqueous solution of phthalate  

International Nuclear Information System (INIS)

Radiolysis dilute aqueous solution of dimethyl phthalate, DMP, with 60Co ?-rays was investigated by using UV and IR spectrophotometric methods, gas chromatography, high-speed liquid chromatography. For both nitrogen- and oxygen-saturated solutions, an approximately linear relationship was held between the consumption of DMP and dose. The yield for the decomposition of DMP, G(-DMP), was 2.3 for the oxygenated and 1.6 for the deoxygenated solutions. The decomposition of DMP is initiated by the attack of hydroxyl radical on the benzene ring. Hydrated electrons, however, do not contribute to the decomposition. It was strongly suggested from the UV and IR spectral changes of DMP solutions induced by the irradiation that the elimination of the substituent on the benzene ring together with the ring cleavage reaction occur at rather early stages of the decomposition in the presence of oxygen. Organic acids such as formic, oxalic, and fumaric acids were identified as major products after the high dose irradiation of the oxygenated solution. The irradiation also gave rise to the significant reduction in the total organic carbon (TOC) in the presence of oxygen. The reduction of TOC was nearly the same as the amount of CO2 produced, indicating that in the presence of oxygen, DMP is completely decomposed by radiation into CO2. (author)

1979-01-01

248

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

International Nuclear Information System (INIS)

[en] Varietal improvement is essential if a new impetus is to be given to the French apricot crop. We have accordingly started a mutation breeding programme by bud irradiation. Because of the scarcity of bibliographical data, the first step was to study the budwood radiosensitivity of the apricot cultivars used as starting material. Budsticks of various cultivars were exposed to increasing doses of acute gamma rays. The physiological effects induced by irradiation were evaluated from bud survival and growth. These results allowed us, in the first instance, to fix the optimal dose range for dormant buds irradiated at 6 to 7 Gy/mm. Observations in the nursery on scions from the second vegetative generation (V2) already showed the limits of bud irradiation. Further observations in the orchard are need to estimate the value of this method for apricot breeding[fr] L'amelioration ou la diversification de la gamme varietale demeure une necessite pour le maintien ou la relance de la culture de l'abricotier en France. Dans cette optique un programme de mutagenese induite par irradiation de bourgeons a ete envisage. Une connaissance approfondie de la radiosensibilite du materiel vegetal choisi a ete une premiere etape indispensable, en raison notamment du peu de donnees bibliographiques a ce sujet. Ainsi des rameaux greffons de differents cultivars d'abricotier ont ete soumis a des doses croissantes de rayonnement gamma a fort debit. Les effets physiologiques radioinduits d'ordre quantitatif sont estimes selon des criteres couramment utilises (taux de survie, croissance). Ces resultats constituent des elements de base pour situer dans un premier temps la dose ''optimale'' de traitement pour des conditions relativement bien definies (stade dormant des bourgeons, debit de dose de 6 a 7 Gy/mn). Des scions de deuxieme generation vegetative (V2) ont ete constitues afin d'observer, en pepiniere puis en verger, les effets genetiques provoques par les differents traitements effectues. On devrait ainsi mieux determiner la dose optimale de traitement et, plus generalement, mieux apprehender l'interet de la methode utilisee. Les observations effectuees en pepiniere font deja apparaitre les limites de cette methode

1988-01-01

249

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

International Nuclear Information System (INIS)

[en] 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)[pt] O uso das radiacoes ionizantes na inativacao de microrganimos responsaveis pela deterioracao de alimentos e causadores de toxinfeccoes alimentares, constitui aplicacao da energia nuclear para fins verdadeiramente pacificos. As toxinfeccoes alimentares em nosso meio sao causadas em grande parte por Salmonella enteritidis var. typhimurium. Neste trabalho foram irradiadas 119 amostras de leite tipo B, contendo cerca de 150.000 salmonelas por ml, com doses entre 100 a 1.100 Gray (Gy), sendo dois lotes de sobreviventes re-irradiados com doses ate 2.500 Gy. As bacterias nao irradiadas previamente, foram totalmente inativadas com doses de 1.100 Gy. Salmonella enteritidis var typhimurium descendentes dos sobreviventes de 1.000 Gy, sobreviveram a dose de 1.200 Gy, estas, re-irradiadas, resistiram a dose de 1.900 Gy. A dose letal minima para Salmonella enteritidis var. typhimurium da radiacao gama do Cobalto-60 e de 1.200 Gy; a re-irradiacao de sobreviventes induzem ao aparecimento de germes mais radio-resistentes. (autor)

1988-01-01

250

Behavior of triterpenes from Maytenus aquifolium Martius ('espinheira santa') upon X- and gamma-rays irradiation  

International Nuclear Information System (INIS)

The behavior of the triterpenes friedelin and friedelan-3-ol, contained on the leaves of Maytenus aquifolium Martius (Celastraceae), upon several doses of X- and ?-rays (10 to 100 kGy), was investigated by high resolution gas chromatography (HRGC) and high resolution gas chromatography -mass spectrometry (HRGC-MS). The friedelin content has not changed with ?-irradiation, but the content of friedelan-3-ol decreased around 17% at doses of 10, 20 and 40 kGy and around 27% at doses of 60, 80 and 100 kGy. The levels of both triterpenes remained unchanged even at higher X-ray doses. Lupen-3-one was detected by HRGC-MS. (author).

1997-01-01

251

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

252

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

253

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.

2009-01-01

254

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)

2007-01-01

255

Simulation of survival curves in several bacteria irradiated with ultraviolet and gamma rays  

Energy Technology Data Exchange (ETDEWEB)

Although ultraviolet and gamma sterilization were routinely used, D[sub 10]-values and D[sub 99.9]-values have been used in actual applications. However, our preliminary results showed that UV-survival curves were sigmoidal and [gamma]-curves were exponential having a shoulder at beginning in many strains. This study was conducted to make clear the reason of occurence of the sigmoid in UV survival curves, at first. Both survival curves of spore cells and vegetable cells in Bacillus subtilis against UV-irradiation are shown with the same sigmoidal pattern. It is clarified that the difference in sensibilities of vegetative and spore cells could not account for the presence of tails. The UV sterilized data have been simulated by adapting a multi hit theory and taking into account the decrease in UV-intensity in liquid suspensions due to Lambert's law. These also follows that the above multi-hit simulation is effective for the [gamma] data and four hits are best fitted to the observed data in both cases of bacteria and fungi. From these results, it is demonstrated that if D[sub 10]-value and L-value are used as indices for practical sterilization and if a target area and a hit number, a parameter of penetration in UV sterilization are considered, the sterilization level will become more accurate than that as determined by D[sub 10]- and D[sub 99.9]-values currently used. (author).

Ishiguro, Etsuji; Miyazato, Mitsuru (Kagoshima Univ. (Japan). Faculty of Agriculture); Murata, Satoshi

1993-01-01

256

Simulation of survival curves in several bacteria irradiated with ultraviolet and gamma rays  

International Nuclear Information System (INIS)

Although ultraviolet and gamma sterilization were routinely used, D10-values and D99.9-values have been used in actual applications. However, our preliminary results showed that UV-survival curves were sigmoidal and ?-curves were exponential having a shoulder at beginning in many strains. This study was conducted to make clear the reason of occurence of the sigmoid in UV survival curves, at first. Both survival curves of spore cells and vegetable cells in Bacillus subtilis against UV-irradiation are shown with the same sigmoidal pattern. It is clarified that the difference in sensibilities of vegetative and spore cells could not account for the presence of tails. The UV sterilized data have been simulated by adapting a multi hit theory and taking into account the decrease in UV-intensity in liquid suspensions due to Lambert's law. These also follows that the above multi-hit simulation is effective for the ? data and four hits are best fitted to the observed data in both cases of bacteria and fungi. From these results, it is demonstrated that if D10-value and L-value are used as indices for practical sterilization and if a target area and a hit number, a parameter of penetration in UV sterilization are considered, the sterilization level will become more accurate than that as determined by D10- and D99.9-values currently used. (author)

1993-01-01

257

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

International Nuclear Information System (INIS)

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

1999-01-01

258

Effect of extremely low temperature gamma ray irradiation on polymer materials  

International Nuclear Information System (INIS)

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

1991-01-01

259

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

International Nuclear Information System (INIS)

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

1995-01-01

260

Nanoparticles of Al{sub 2}O{sub 3}:Cr as a sensitive thermoluminescent material for high exposures of gamma rays irradiations  

Energy Technology Data Exchange (ETDEWEB)

Aluminum Oxide (Al{sub 2}O{sub 3}) doped with proper activators is a highly sensitive phosphor commonly used for radiation dosimetry using thermoluminescence (TL) technique. Nanoparticles of this material activated with Chromium (Cr) have been synthesized using the propellant chemical combustion technique and studied for their TL response. They were characterized by X-ray diffraction and scanning electron microscope. The synthesized material has spherical nanoparticles with grain size around 25 nm. These nanoparticles were exposed to heavy doses from {gamma}-rays of {sup 137}Cs. The TL glow curves show a prominent peak at around 474 K. This peak is found to be sensitive for high exposures of {gamma}-rays and has linear response in the range of 100 Gy-20 kGy without showing saturation. This remarkable result suggests that Al{sub 2}O{sub 3}:Cr nanoparticles might be used for the dosimetry of food and seed irradiations.

Salah, Numan, E-mail: alnumany@yahoo.co [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Khan, Zishan H.; Habib, Sami S. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2011-02-15

 
 
 
 
261

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

UK PubMed Central (United Kingdom)

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

Dedieu A; Sahinovic E; Guérin P; Blanchard L; Fochesato S; Meunier B; de Groot A; Armengaud J

2013-01-01

262

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

Directory of Open Access Journals (Sweden)

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

Dedieu Alain; Sahinovic Elodie; Guérin Philippe; Blanchard Laurence; Fochesato Sylvain; Meunier Bruno; de Groot Arjan; Armengaud Jean

2013-01-01

263

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

264

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

CERN Multimedia

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

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

2012-01-01

265

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

International Nuclear Information System (INIS)

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

2006-01-01

266

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 H2O2- 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 H2O2- 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 H2O2- 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

267

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)

2004-01-01

268

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-02-01

269

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

International Nuclear Information System (INIS)

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

1999-01-01

270

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)

2002-01-01

271

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

272

Effects of heat-treatment and gamma-ray irradiation on the etch-pit formation in allyl diglycol carbonate resin  

International Nuclear Information System (INIS)

Allyl diglycol carbonate resin plates possessing alpha tracks were etched after heat-treatment, or after gamma-ray irradiation. The strong heat-treatment and irradiation brought similar effects to two indicators: etch-pit diameter and bulk etching rate. The heat-treatment above 120degC lasting for 1 h and irradiation above 4.0 x 102 Gy increased the indicators and caused the etch-pits to disappear faster. On the other hand, mild heat-treatment brought the opposite effects to under-cured resin. A reduction of the etch-pit diameter was observed in the resin exposed to heat-treatments between 80degC and 120degC lasting for 1 h. These phenomena were observed in the study of plates in which alpha tracks were made after the above mentioned heat-treatment or irradiation. These results suggest not only the conditions under which the resin may be used, but also the possibility of enhancement or suppression of etching speed, and of estimation of thermal history or measurement of gamma-ray dosage. (author).

1997-01-01

273

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1983-12-01

274

The role of secondary defects in the loss of energy resolution of fast-neutron-irradiated HPGe gamma-ray detectors  

Energy Technology Data Exchange (ETDEWEB)

This paper reports on the resolution characteristics of high-purity germanium gamma-ray detectors irradiated with fast neutrons that are studied in detail. The influence of the neutron fluence on the energy resolution, as well as the annealing temperature of irradiated detectors are investigated. Similarities are observed between the annealing behavior of the defects created by fast neutron irradiation in high-purity germanium and the changes in the energy resolution of the detectors when they are annealed. The energy resolution of the detectors measured by the means of a resolution factor which takes into account tailing effects has been investigated. Its behavior has been illustratively explained by the differences between the respective role of the stable defects at low temperature ({lt}100 K) and those formed by a thermal treatment up to room temperature.

Fourches, N. (Centre d' Etudes de Saclay, DPHN/STEN, 91991 Gif-sur-Yvette (FR)); Huck, A.; Walter, A. (Centre de Recherches Nucleaires, IN2P3-CNRS, Univ. Louis Pasteur, BP 20, F-67037 Strasbourg Cedex (FR))

1991-12-01

275

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

International Nuclear Information System (INIS)

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

1994-01-01

276

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

International Nuclear Information System (INIS)

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

1988-01-01

277

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

Directory of Open Access Journals (Sweden)

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

Anand M. Badigannavar and Suvendu Mondal

2010-01-01

278

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  

Energy Technology Data Exchange (ETDEWEB)

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 (TH)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.

Hannan, M.A.; Gibson, D.P.

1985-10-01

279

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.

1985-01-01

280

Indirect genotoxic effect of gamma rays in human peripheral lymphocytes  

Energy Technology Data Exchange (ETDEWEB)

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

Ahmet Kayraldiz; Mehmet Topaktas [Cukurova Univ., Adana (Turkey)

2001-03-01

 
 
 
 
281

Gamma-ray sources  

International Nuclear Information System (INIS)

[en] 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.)

1980-01-01

282

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; Xu An; Wu Li-Jun; Yao Jian-Min; Yang Jian-Bo; Yu Zeng-Liang

2004-01-01

283

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 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 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 (more) 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).

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

2004-01-01

284

Galactic gamma ray astronomy  

Energy Technology Data Exchange (ETDEWEB)

During the last decade the exploration of the sky in the light of gamma rays has begun by means of satellite-and balloon-borne instruments. Like in other ranges of the electromagnetic spectrum the Milky Way clearly stands out against the rest of the sphere. Part of the galactic ..gamma..-ray emission is due to discrete sources, part is diffuse in origin and is produced in interstellar space. Some of the discrete ..gamma..-ray sources are radio pulsars, the nature of the other sources is still unknown. The intensity distribution of the diffuse galactic ..gamma..-ray component is consistent with a decrease of the cosmic-ray intensity towards the outer part of the galaxy. The identification of the cosmic-ray sources will be one of the main objectives of the next generation of ..gamma..-ray telescopes.

Schoenfelder, V.

1982-05-01

285

Radiation sensitivity of microorganisms adhering to the crude drug ``Bezoar Bovis`` and stability of its main components for {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

The sterilization dose (SD) of {gamma} rays required for the microbial-contaminated crude drug ``Bezoar Bovis`` and the residual rates of its characteristic and effective components, bilirubin and some kinds of cholic acid, were studied experimentally. Samples of Bezoar Bovis made in America were used. The contamination level of the samples was 2.2 x 10{sup 8} cells of bacteria and 6.0 x 10{sup 5} spores of fungi per g specimen. The survival rate of these microorganisms showed nearly an exponential dependence on radiation dose. The decimal reduction doses (D{sub 10}) for the bacteria and fungi were found to be 1.5 kGy and 1.1 kGy respectively. From these values, the dose required for attaining the contamination level provided by the administrative guidance (Bacteria, <1.0 x 10{sup 3} cells/g; Fungi, <1.0 x 10{sup 2} spores/g) were estimated to be 7.5 kGy and 4.3 kGy, respectively. The G-values for bilirubin, cholic acid and deoxycholic acid were calculated to be 13, 6 and 8, respectively. If the sterilization treatment is carried out with a dose less than 10 kGy on the specimen in a dry powder state, the reduction of the main components such as bilirubin and cholic acids by {gamma}-ray irradiation is considered to be negligible. (author)

Ohnishi, Tokuhiro; Okamoto, Shinichi [Research Inst. for Advanced Science and Technology, Osaka (Japan); Kimura, Syojiro; Taimatsu, Meiko; Endo, Akira

1994-03-01

286

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

International Nuclear Information System (INIS)

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

2003-01-01

287

{sup 60}Co gamma-rays irradiation effect in DC performance of AlGaN/GaN high electron mobility transistors  

Energy Technology Data Exchange (ETDEWEB)

Unpassivated/passivated AlGaN/GaN high electron mobility transistors (HEMTs) were exposed to 1.25 MeV {sup 60}Co gamma-rays at a dose of 1 Mrad(Si). The saturation drain current of the unpassivated devices decreased by 15% at 1 Mrad gamma-dose, and the maximal transconductance decreased by 9.1% under the same condition; moreover, either forward or reverse gate bias current was significantly increased, while the threshold voltage is relatively unaffected. By sharp contrast, the passivated devices showed scarcely any change in saturation drain current and maximal transconductance at the same gamma dose. Based on the differences between the passivated HEMTs and unpassivated HEMTs, adding the C-V measurement results, the obviously parameter degradation of the unpassivated AlGaN/GaN HEMTs is believed to be caused by the creation of electronegative surface state charges in source-gate spacer and gate-drain spacer at the low dose (1 Mrad). These results reveal that the passivation is effective in reducing the effects of surface state charges induced by the {sup 60}Co gamma-rays irradiation, so the passivation is an effective reinforced approach.

Gu Wenping; Chen Chi; Duan Huantao; Hao Yue; Zhang Jincheng; Wang Chong; Feng Qian; Ma Xiaohua, E-mail: yhao@xidian.edu.c, E-mail: wpgu@yahoo.c [Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

2009-04-15

288

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

International Nuclear Information System (INIS)

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

1998-01-01

289

Gamma-ray bursts  

Energy Technology Data Exchange (ETDEWEB)

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 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)

Wijers, R. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

1998-04-01

290

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

Energy Technology Data Exchange (ETDEWEB)

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.

Schroeder, J.H.

1980-07-01

291

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

International Nuclear Information System (INIS)

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

1976-01-01

292

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)

2008-01-01

293

Microdosimetric distributions for nanometer-size targets in water irradiated with 60Co gamma rays: frequency distributions of effective primary events by individual tracks of electrons.  

Science.gov (United States)

A calculation method of frequency distributions for the microdosimetric quantity j (number of effective primary events per track per target), fj , is presented. fj distributions are calculated for nanometer-size targets in water irradiated with 60Co gamma rays, using degradation spectra of total electrons in water, phi t(E). Further, fractional total electron differential fluences effective to produce j effective primary events, phi t(E, j), are calculated. It is found that the frequency for occurrence of no effective primary event tracks (tracks traversing the target without any effective primary event inside the target) is very large for nanometer-size targets, and that the delta-ray effect on the fj distribution becomes more significant with the decrease of the target size and especially j effective primary events (j greater than or equal to 1) for very small targets are due mostly to delta rays. PMID:6718686

Oda, N; Iwanami, S

1984-04-01

294

Microdosimetric distributions for nanometer-size targets in water irradiated with 60Co gamma rays: frequency distributions of effective primary events by individual tracks of electrons.  

UK PubMed Central (United Kingdom)

A calculation method of frequency distributions for the microdosimetric quantity j (number of effective primary events per track per target), fj , is presented. fj distributions are calculated for nanometer-size targets in water irradiated with 60Co gamma rays, using degradation spectra of total electrons in water, phi t(E). Further, fractional total electron differential fluences effective to produce j effective primary events, phi t(E, j), are calculated. It is found that the frequency for occurrence of no effective primary event tracks (tracks traversing the target without any effective primary event inside the target) is very large for nanometer-size targets, and that the delta-ray effect on the fj distribution becomes more significant with the decrease of the target size and especially j effective primary events (j greater than or equal to 1) for very small targets are due mostly to delta rays.

Oda N; Iwanami S

1984-04-01

295

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

International Nuclear Information System (INIS)

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

1994-01-01

296

Studies on the valyl-h-tRNA synthetase of chick embryo brain irradiated with 60Co gamma-rays, in vivo.  

UK PubMed Central (United Kingdom)

18-day-old chick embryos (Leghorn) were irradiated in vivo with 1,2,3,4,5 or 7 Gy 60Co gamma-rays (dose rate = 0.9 Gy/min). Twenty-four hours after irradiation the activity of valyl-tRNA synthetase isolated from the brains was determined and compared with that of the non-irradiated control. The aminoacylation activity was found to decrease exponentially as a function of the dose (D37 = 6 Gy). Irradiation caused a more pronounced decrease in valyl-tRNA synthetase activity in 18-day-old than in 14-day-old chick embryos and induced in the valine-dependent ATP-PPi exchange reaction less change than in the valyl-tRNA FORMATion. The exposure of 15-day-old chick embryos to a dose of 4 or 5 Gy induced, respectively, a 40 or 20 per cent increase in enzyme activity of VRS (prepared on day 19 of embryonic life) relative to the control. In these experiments a decrease of Km value for tRNA has been found. The change in the number of sulfhydryl groups was also investigated.

Bölöni E

1980-01-01

297

gamma. -ray bursts  

Energy Technology Data Exchange (ETDEWEB)

The time histories, size spectrum, spatial distribution, and repetition rates of ..gamma..-ray bursts are reviewed briefly. Evidence for a neutron star origin for ..gamma..-ray bursts may be found in many of these aspects of bursters. New results from optical searches are described. Substantial progress has been made recently in the optical identification of the 1978 November 19 burst. 57 references, 8 figures.

Hurley, K.

1983-01-01

298

Gamma ray camera  

Energy Technology Data Exchange (ETDEWEB)

An anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the anger camera, the image intensifier tube having a negatively charged flat scintillator screen and a flat photocathode layer and a grounded, flat output phosphor display screen all of the same dimension (Unity image magnification) and all within a grounded metallic tube envelope and having a metallic, inwardly concaved input window between the scintillator screen and the collimator.

Robbins, C.D.; Wang, S.

1980-09-09

299

Gamma ray optics  

Energy Technology Data Exchange (ETDEWEB)

Via refractive or diffractive scattering one can shape {gamma} ray beams in terms of beam divergence, spot size and monochromaticity. These concepts might be particular important in combination with future highly brilliant gamma ray sources and might push the sensibility of planned experiments by several orders of magnitude. We will demonstrate the experimental feasibility of gamma ray monochromatization on a ppm level and the creation of a gamma ray beam with nanoradian divergence. The results are obtained using the inpile target position of the High Flux Reactor of the ILL Grenoble and the crystal spectrometer GAMS. Since the refractive index is believed to vanish to zero with 1/E{sup 2}, the concept of refractive optics has never been considered for gamma rays. The combination of refractive optics with monochromator crystals is proposed to be a promising design. Using the crystal spectrometer GAMS, we have measured for the first time the refractive index at energies in the energy range of 180 - 2000 keV. The results indicate a deviation from simple 1/E{sup 2} extrapolation of X-ray results towards higher energies. A first interpretation of these new results will be presented. We will discuss the consequences of these results on the construction of refractive optics such as lenses or refracting prisms for gamma rays and their combination with single crystal monochromators.

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

2012-07-09

300

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

International Nuclear Information System (INIS)

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

1977-01-01

 
 
 
 
301

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

302

Nature of gamma-ray burst spectra  

International Nuclear Information System (INIS)

The recent discovery of low-energy absorption features in the spectra of gamma-ray bursts (GRBs) reported by Murakami et al. (1988) is discussed in the context of a new model for gamma-ray emission in isolated neutron-star sources. It is shown that the whole GRB spectrum may be due to irradiation of a reprocessing and reflecting boundary near a source of power-law gamma radiation. In this picture, the gamma-rays originate far above the surface of a magnetized neutron star where attenuation of the spectrum by pair production is minimal. The surface layers of the neutron star absorb a fraction of the gamma-ray energy and reflect some of the gamma-rays. The resultant spectrum is comprised of a power law at high energy, a steep component at intermediate energy, and a thermal component at low energy. There is a slight enhancement of the gamma-ray flux near E0 that may be the cause of the apparent d(-)d(+) annihilation line seen in some bursts. 27 references

1988-01-01

303

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)

2005-01-01

304

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

Energy Technology Data Exchange (ETDEWEB)

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

Cardi, Bruno Andrade

1999-07-01

305

Gamma ray camera  

Energy Technology Data Exchange (ETDEWEB)

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

Perez-Mendez, Victor (Berkeley, CA)

1997-01-01

306

Development of polytetrafluoroethylene (PTFE) crosslinking technology by {sup 60}Co {gamma}-rays  

Energy Technology Data Exchange (ETDEWEB)

The irradiation vessel for polytetrafluoroethylene (PTFE) crosslinking by {sup 60}Co {gamma}-rays was constructed, and the crosslinking was studied. By using {gamma}-rays irradiation, the thick PTFE material or various shaped materials could be crosslinked uniformly, and the control of material temperature was rather easy because {gamma}-rays heating was much small. (author)

Ikeda, Shigetoshi; Kasai, Noboru; Oshima, Akihiro; Kusano, Hiroo; Haruyama, Yasuyuki; Seguchi, Tadao [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1999-02-01

307

Formation of solid particles from aqueous solution of palladium sulfate and of palladium sulfate-silver sulfate by gamma-ray irradiation  

International Nuclear Information System (INIS)

Aqueous solutions containing (a) palladium sulfate (0.1mM), (b) palladium sulfate (0.5mM) and silver sulfate (0.5mM), and (c) silver sulfate (0.1mM) saturated with nitrogen were irradiated with cobalt 60 gamma radiations (dose rate, 2.35 and 11.2kGy/h). The pH's of most solutions were 1.43 and 0.43. Formation of fine particles was studied from the decrease of optical absorption of metal ions and from the increase of turbidity of the solutions. Palladium ion was reduced to form solid particles under any pH's studied in solutions (a) and (b). Silver ion was reduced to form solid particles under any pH's studied in solution (b), while no reduction of silver ion was observed below pH=4 in solution (c). The result indicates that particles of 6 or 7 silver atoms are formed during gamma ray irradiation of solutions (b) and (c). (author)

1994-01-01

308

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).

1990-01-01

309

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

International Nuclear Information System (INIS)

[en] The burn up of natural U3O8 that occurs by the action of thermal neutrons was determined, using the radioisotopes 144Ce, 137Cs, 103Ru, 106Ru and 95Zr as monitors. The determination of the burn up was made using both destructive and non-destructive methods. In the non-destructive method, the technique of direct gamma-ray spectrometry was used and the radioisotopes mentioned were simultaneously counted in a Ge-Li detector. In the radiochemical method the same radioisotopes were isolated one from the other and from all other fission products before counting. The solvent extraction technique was used for the radiochemical separation of uranium, cerium, cesium and ruthenium. To separate zirconium and niobium, adsorption in silica-gel was used. The extraction agent employed to isolate cesium was dipycrilamine and for the separation of the other radioisotopes Di-(2-Ethyl Hexyl) Phosphoric acid (HDEHP) was used. (Author)[pt] Determinou-se a queima ocorrida em amostras de U3O8 (uranio natural) irradiado com neutrons termicos, usando como monitores os radioisotopos 144Ce, 137Cs, 103Ru, 106Ru e 95Zr. A determinacao da queima foi feita usando-se o metodo destrutivo e o nao destrutivo. Na determinacao da queima pelo metodo nao destrutivo empregou-se a tecnica de espectrometria de raios gama, em que cada um dos radioisotopos mencionados foi contado em presenca dos demais, com o uso de detector de Ge-Li. Na determinacao da queima pelo metodo radioquimico cada um daqueles radioisotopos foi separado de mistura de produtos de fissao, antes de ser efetuada a sua contagem. Foi empregada a tecnica de extracao com solvente para a separacao radioquimica entre o uranio, cerio, cesio e rutenio, ao passo que para isolar zirconio e niobio foi utilizada a adsorcao em silica-gel. O agente extraente usado para isolar o cesio foi a dipicrilamina e para a separacao dos cemais produtos de fissao foi usado o acido di-(2-etil hexil) fosforico (HDEHP). (Autor)

1979-01-01

310

Gamma-ray bursts.  

UK PubMed Central (United Kingdom)

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

Gehrels N; Mészáros P

2012-08-01

311

Gamma Ray Bursts  

CERN Document Server

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

Gehrels, Neil; 10.1126/science.1216793

2012-01-01

312

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

313

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

International Nuclear Information System (INIS)

Using electron paramagnetic resonance (EPR), we studied the tree radical formation in high-density Polyethylene (HDPE), polyamide (PA6) and HDPE/PA6 (80/20)blend, irradiated with integral doses (D), 0

2003-01-01

314

Formation of covalent linkages between nuclear and protein constituents of ribosomes of E. coli MRE 600 irradiated by gamma rays  

International Nuclear Information System (INIS)

[en] Gamma-irradiation of E.coli MRE 600 ribosomes in aqueous suspensions led to covalent linkages between the RNA and some ribosomal proteins. The presence of oxygen during the irradiation strongly inhibited this phenomenon. It appears clearly that only a few proteins were able to participate in these cross-linking reactions, which occurred simultaneously in the two sub-units. The radiochemical yield was determined at several concentrations and was relatively low. (author)

1977-01-01

315

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 conclus 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)

2003-11-26

316

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

International Nuclear Information System (INIS)

[en] Total aerobic bacteria in spices used in this study were determined to be 1 x 106 to 6 x 107 per gram. A study on the inactivation of microorganisms in spices showed that doses of 6-9 kGy of EB (electron-beams) or ?-irradiation were required to reduce the total aerobic bacteria to below 103 per gram. However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These differences of radiation sensitivities between EB and ?-rays was explained by dose rate effect on oxidation damage to microorganisms from the results of radiation sensitivities of Bacillus pumilus and B. megaterium spores at dry conditions. On the other hand, these high dose rate of EB irradiation suppressed the increase of peroxide values in spices at high dose irradiation up to 80 kGy. However, components of essential oils in spices were not changed even irradiated up to 50 kGy with EB and ?-rays. (author)

1994-01-01

317

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

International Nuclear Information System (INIS)

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

1997-01-01

318

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

International Nuclear Information System (INIS)

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

2007-02-07

319

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

International Nuclear Information System (INIS)

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

1991-01-01

320

Effects of neonatal. gamma. -ray irradiation on rat hippocampus: Pt. 2; Development of excitatory amino acid binding sites  

Energy Technology Data Exchange (ETDEWEB)

In the rat, neonatal irradiation produces a destruction of denate granule cells and prevents the development of the mossy fibre-CA3 pyramidal cell synapse. The developmental increase of high affinity kainate binding sites in the stratum lucidum was reduced on the irradiated side as compared with the control side. This suggests that a proportion of high affinity kainate binding sites is associated with mossy fibres. In contrast, the development profile of N-methyl-D-aspartate binding sites, which are associated with associational and commissural synapses in CA3, was not affected by irradiation. The role that afferent fibres may play in the development of pyramidal cells is discussed in connection with the modulatory effects of glutamate receptors on the development of neurons. (author).

Dessi, F.; Represa, A.; Ben-Ari, Y. (Institut National de la Sante et de la Recherche Medicale (INSERM), 75 - Paris (France))

1991-01-01

 
 
 
 
321

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

322

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

International Nuclear Information System (INIS)

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

2002-01-01

323

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)

[en] 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

1980-01-01

324

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

325

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

CERN Document Server

1.1 This test method covers the determination of the number of atoms of 137Cs in aqueous solutions of irradiated uranium and plutonium nuclear fuel. When combined with a method for determining the initial number of fissile atoms in the fuel, the results of this analysis allows atom percent fission (burn-up) to be calculated (1). The determination of atom percent fission, uranium and plutonium concentrations, and isotopic abundances are covered in Test Methods E 267 and E 321. 1.2 137Cs is not suitable as a fission monitor for samples that may have lost cesium during reactor operation. For example, a large temperature gradient enhances 137Cs migration from the fuel region to cooler regions such as the radial fuel-clad gap, or, to a lesser extent, towards the axial fuel end. 1.3 A nonuniform 137Cs distribution should alert the analyst to the potential loss of the fission product nuclide. The 137Cs distribution may be ascertained by an axial gamma-ray scan of the fuel element to be assayed. In a mixed-oxide fu...

American Society for Testing and Materials. Philadelphia

2008-01-01

326

Microdosimetric distributions for nanometer-size targets in water irradiated with /sup 60/Co gamma rays: frequency distributions of effective primary events by individual tracks of electrons  

Energy Technology Data Exchange (ETDEWEB)

A calculation method of frequency distributions for the microdosimetric quantity j (number of effective primary events per track per target), f/sub j/, is presented. f/sub j/ distributions are calculated for nanometer-size targets in water irradiated with /sup 60/Co ..gamma.. rays, using degradation spectra of total electrons in water, phi/sub t/(E). Further, fractional total electron differential fluences effective to produce j effective primary events, phi/sub t/(E,j), are calculated. It is found that the frequency for occurrence of no effective primary event tracks (tracks traversing the target without any effective primary event inside the target) is very large for nanometer-size targets, and that the delta-ray effect on the f/sub j/ distribution becomes more significant with the decrease of the target size and especially j effective primary events (j greater than or equal to 1) for very small targets are due mostly to delta rays.

Oda, N. (Tokyo Inst. of Tech., Japan); Iwanami, S.

1984-04-01

327

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-10-01

328

FFTF shield and gamma-ray measurements  

International Nuclear Information System (INIS)

An extensive measurements program was carried out prior to routine operation of the Fast Flux Test Facility (FFTF) to establish (1) the attenuation characteristics of the reactor shield, (2) the nuclear environment in the core, and (3) to assure that the facility could be operated safely from the standpoint of radiological considerations. Reactor shield neutron fluxes were measured primarily using radioactivant detectors irradiated in special test vehicles placed at assessible locations. Preliminary evaluation of the data indicated shield performance consistent with design calculations. Gamma ray measurements employed a variety of ionization chambers and calorimeters as well as thermoluminescent dosimeters, selfpowered gamma ray detectors, and thermal expansion difference temperature monitors. The gamma ray experimental results are consistent and also in relatively good agreement with analytical predictions. Plant shield survey employed standard radiation survey instruments

1983-01-01

329

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

International Nuclear Information System (INIS)

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

2004-01-01

330

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

International Nuclear Information System (INIS)

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

1996-01-01

331

Glioblastoma multiforme following prophylactic cranial irradiation and intrathecal methotrexate in a child with acute lymphocytic leukemia. [. gamma. rays; infants  

Energy Technology Data Exchange (ETDEWEB)

Cases of radiation-induced glioma in humans are extremely rare. A 2-year-old boy with acute lymphocytic leukemia had received prophylactic cranial irradiation (2400 rad/2 1/2 weeks) and intrathecal methotrexate. Five years later he developed a glioblastoma multiforme on the left cerebral hemisphere while the leukemia was in remission. This is the first reported association of these disorders. It is possible that the glioma may have been induced by radiation and/or chemotherapy.

Chung, C.K.; Stryker, J.A.; Cruse, R.; Vannuci, R.; Towfighi, J.

1981-06-01

332

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

International Nuclear Information System (INIS)

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

1973-01-01

333

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

International Nuclear Information System (INIS)

[en] 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.

2009-05-15

334

Expression of Jun and p53 Genes from the Brain of Rats Irradiated with {sup 60}Co {gamma}-ray  

Energy Technology Data Exchange (ETDEWEB)

Damage produced by radiation elicits a complex response in mammalian cells. Including growth rate changes and the induction of a variety of genes associated with growth control and apoptosis. At doses of 10,000 cGy or greater, the exposed indivisual was killed in a matter of minutes to a couple of days. With symptoms consistent with pathology of the central nervous system(CNS) including degenerative changes. The nature of the damege in irradiated cells underlies the unique hazads of ionizing radiation. Radiation injury CNS is a rare event in clinical medicine, but it is catastrophic for the patient in whom it occurs. The incidience of cerebral necrosis has been reportes as high as 16% for doses greater than 6,000 cGy. In this study, the effect of radiation on brain tissues was studied in vivo. Jun and p53 genes in the rat brain were induced by whole body irradiation of rat with 60Co in doses between 1 Gy and analyzed for expression analyses were done using 1.8 Kb and 0.8 Kb-pGEM-2-JUN/Eco RI/Pst I fragments, 2.0 Kb-php53B/Bam HI fragment and 1.1 Kb-pBluescript SK?ACTIN/Eco RI fragment as the digoxigenin or [a{sup 32}P]dCTPlabeled probes for Jun, p53 and {beta}-actin genes, respectively.Jun gene seemed to be expressed near the threshold levels in 1 hour after irradiation of 60Co in dose less than 1 Gy and was expressed in maximum at 1 hour after irradiation of 60Co in dose of 30 Gy. Jun was expressed increasingly with time until 5 or 6 hours after irradiation of 60Co in dose of 1 Gy and 10 Gy. After irradition of 60Co in dose between 20 Gy and 100Gy, the expression of Jun was however increased to peak in 2 hours and decreased thereafter.P53 gene in this study also seemed to be expressed near the threshold levels in 1 hours after irradiation of 60Co in less than 1 Gy and was expressed in maximum and 6 hours after irradiation of 60Co in dose of 1 Gy. P53 was expressed increasingly with time until 5 or 6 hours after irradition of 60Co in dose between 1 Gy and 40 Gy. After irradition of 60Co in dose of 50 Gy and 100Gy. The expression of p53 was however increased in peak in 2 hours and decreased thereafter. The expression of Jun and p53 genes was not correlative in the brain tissue from rats. It seemed to be very important for the establishment of the optimum conditions for the animal studies relevant to the response of genes inducible on DNA damage to ionizing radiation in mammalian cells. But there are many limitations to the animal studies such as the ununiform patterns of gene expression from the tissue because of its complex compositions. It is necessary to overcome the limitations for development of in situ Northern analysis.

Kim, Yong Seok; Woo, Chong Kyu; Lee, Yong Sung; Koh, Jai Kyung; Chun, Ha Chung; Lee, Myung Za [Hanyang University College of Medicine, Seoul (Korea, Republic of)

1996-12-15

335

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

Energy Technology Data Exchange (ETDEWEB)

The degradation of the mechanical behaviour of EPDM elastomers used as cable insulation materials has been investigated by mechanical spectroscopy and tensile tests for different formulations: unvulcanised EPDM, vulcanised and stabilised elastomer with an antioxidant. In all cases, {gamma}-irradiation of EPDM under oxygen leads to a reduction of the molecular mobility indicated by the shift of the glass transition relaxation temperature towards higher temperatures. Moreover, the molecular flow occurring above T{sub g} is suppressed after irradiation for the unvulcanised EPDM providing evidence of cross-linking. The competition between cross-linking and chain scissions is shown by the decrease of the storage modulus above the crystallites melting temperature ({approx}40 deg. C) at doses larger than 100 kGy. A strong increase of the Young modulus and reduction of the elongation at break of the non-vulcanised EPDM becoming more brittle are shown by stress/strain characterisations performed at 80 deg. C. At the opposite vulcanised EPDM exhibits higher elongation at break after crystallites melting. This evolution is interpreted by the competition between cross-linking and chain scissions, being hindered by the crystallites at room temperature. The intrinsic irradiation effects can be isolated after crystallite melting. The reduction of the molecular mobility can be explained by a chemi-crystallisation process assisted by chain scissions, leading to a more rigid phase upon irradiation.

Davenas, J. E-mail: joel.davenas@univ-lyon1.fr; Stevenson, I.; Celette, N.; Vigier, G.; David, L

2003-08-01

336

The Effect Of SEA On Long Tail Monkeys (Macaca Fascicularis) Lymphocyte Culture Gamma Ray-Irradiated In Vitro  

International Nuclear Information System (INIS)

Staphylococus enteroxine (SEA) is one of toxins produced by the bacterium Staphylococus aureus. In the culture, SEA has proven as a potent stimulator of lymphocytes in man event at fg/ml concentrations. This research studied the effect of SEA compared to Phytohaemagglutinine (PHA) on the peripheral blood lymphocytes culture of the long-tail monkeys. About 5 ml blood was collected from 5 monkeys and irradiated using Gamma Cell-220 P3TIR with doses of 0 (control); 1.0; 2.0; 3.0 and 4.0 Gy. The blood samples were cultured in the appropriate growth medium based on standard procedure and added with 1.0 ml (0.5 mug/ml) SEA or 0.15 ml PHA. The cultures were then incubated for 96 hours and prepared the slides. The results showed that on the unirradiated peripheral blood lymphocytes of long-tail monkeys the mitotic indices obtained using PHA and SEA are relatively similar. On the irradiated lymphocytes with doses of 1-3 Gy, the mitotic indices using SEA are relatively higher than that of PHA. Dose responses of dicentric, ring and acentric fragment of both PHA and SEA are relatively the same.

2000-01-01

337

Influence of gamma-ray irradiation on optical and thermal degradation of poly (ethyl-methacrylate) (PEMA) polymer  

Directory of Open Access Journals (Sweden)

Full Text Available Polymer based on (polyethyl-methacrylate) (PEMA) were exposed to different doses of gamma radiation up to 100 kGy and the physical properties have been studied. The effects of gamma irradiation on the optical spectrum of PEMA films have been investigated using spectrophotometric measurements of reflectance and transmittance in the wavelength range 200-1100 nm. The structure of the sample is analyzed by X-ray diffraction technique and is found to be amorphous and partially crystalline. TGA studies revealed that the thermal stability of polyethyl methacrylate, improved after irradiation doses up to 100 kGy. On other hand driving absorption coefficient ?(?), consequently the band tail width Ee and optical band gap estimated. This behavior is believed to be associated with the generation of excess of electronic localized states. Also, Optical constants such as refractive index (n), extinction coefficient (K) have been determined using Swanepole method. Optical dispersion parameters and the dispersion parameters, such as Eo (single–oscillator energy), Ed (dispersive energy) are discussed in terms of the single-oscillator Wemple-DiDomenico model.

S. Fares

2012-01-01

338

Gamma ray burst model  

Energy Technology Data Exchange (ETDEWEB)

We present a model for gamma ray bursts based on the compression of neutron stars in close binary systems. Our general relativistic hydrodynamiccomputer simulations of close neutron star binaries have found that as the orbit shrinks the density of the neutron stars rises. This compressional effect has been estimated to produce thermal energies in the neutron stars of the order of magnitude 10{sup 52}to 10{sup 53} ergs on a timescale of a few seconds.This is a possible source of energy for gamma-ray bursts. The hot neutron stars will emit neutrino pairs which will partially recombine to form an electron positron pair plasma. The pair plasma will recombine after expansion to produce photons which closely mimic the characteristics of gamma-raybursts.

Wilson, J.R.; Salmonson, J.D.; Mathews, G.J.

1998-02-17

339

Gamma-ray bursts  

CERN Multimedia

Cosmic gamma ray bursts (GRBs) have fascinated scientists and the public alike since their discovery in the late 1960s. Their story is told here by some of the scientists who participated in their discovery and, after many decades of false starts, solved the problem of their origin. Fourteen chapters by active researchers in the field present a detailed history of the discovery, a comprehensive theoretical description of GRB central engine and emission models, a discussion of GRB host galaxies and a guide to how GRBs can be used as cosmological tools. Observations are grouped into three sets from the satellites CGRO, BeppoSAX and Swift, and followed by a discussion of multi-wavelength observations. This is the first edited volume on GRB astrophysics that presents a fully comprehensive review of the subject. Utilizing the latest research, Gamma-ray Bursts is an essential desktop companion for graduate students and researchers in astrophysics.

Wijers, Ralph A M J; Woosley, Stan

2012-01-01

340

Gamma ray camera  

International Nuclear Information System (INIS)

An Anger gamma ray camera is improved by the substitution of a gamma ray sensitive, proximity type image intensifier tube for the scintillator screen in the Anger camera. The image intensifier tube has a negatively charged flat scintillator screen, a flat photocathode layer, and a grounded, flat output phosphor display screen, all of which have the same dimension to maintain unit image magnification; all components are contained within a grounded metallic tube, with a metallic, inwardly curved input window between the scintillator screen and a collimator. The display screen can be viewed by an array of photomultipliers or solid state detectors. There are two photocathodes and two phosphor screens to give a two stage intensification, the two stages being optically coupled by a light guide. (author)

1979-01-01

 
 
 
 
341

Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products  

Energy Technology Data Exchange (ETDEWEB)

Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

May, J.C. E-mail: may@cber.fda.gov; Rey, L. E-mail: louis.rey@bluewin.ch; Lee, C.-J.; Arciniega, Juan

2004-10-01

342

Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products  

Science.gov (United States)

Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

May, J. C.; Rey, L.; Lee, Chi-Jen; Arciniega, Juan

2004-09-01

343

Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products  

International Nuclear Information System (INIS)

Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

2004-01-01

344

Effect of hydroquinone concentrations on. gamma. -ray induced chromosome aberration frequency in winter wheat  

Energy Technology Data Exchange (ETDEWEB)

Effect on frequency of gamma ray-induced chromosomal aberrations of hydroquinone - one of inhibitors of radical process - was investigated. Dry seeds of winter wheat irradiated with gamma rays were treated with hydroquinone before and after their irradiation. It is established that on irradiation of plant seeds with gamma rays the hydroquinone protection effect is most effective in the case of seed treatment with it before irradiation.

Babaev, M.Sh.; Ismajlov, K.A. (Azerbajdzhanskij Gosudarstvennyj Univ., Baku (USSR))

1982-07-01

345

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

CERN Document Server

The radiation-induced UV-vis spectrum of alpha-terthiophene radical cation in solid is reported. The radical cation initiates an oligomerization in the CTA matrix producing permanently coloured conjugated polarons. The specific net absorbance at 465 nm is linearly related with dose up to 2x10 sup sup 6 sup sup G y, for electrons and gamma irradiation. The decrease of the UV typical absorption (355 nm) and of four IR bands of alpha-terthiophene is linear with dose, as well. Although sensitivity is influenced by dose rate, it turned out that a linear relationship holds between sensitivity and log dose rate, in the range from 2 to 10 sup sup 5 Gy, min. These findings suggest a potential application of the system for dosimetric purposes over a wide range of dose and dose rate.

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

2002-01-01

346

Study on the effect of /sup 60/Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (2)  

Energy Technology Data Exchange (ETDEWEB)

This study is intended to improve scratch resistance of acrylic (hereafter called P.M.M.A.) molded products by first coating acrylic resin with well compatible cross-linking plastics of various kinds and, during the hardening stage, exposing them to radioactive irradiation to build up a hard coat to improve scratch resistance on the surface. From these studies, the following conclusions were reached. By the barrel test which considered scratches and abrasion caused by impacts against relatively hard objects as seen in biting resembling to the wet conditions in oral cavity, fairly well scratch resistance and abrasion resistance were obtained. These treatments give more effects to scratch resistance and abrasion resistance in the brushing conditions rather than in the striking against hard objects. For all specimen, scratch resistance and abrasion resistance in wet conditions can be expected to be three times greater than they are in dry conditions.

Kimura, H. (Osaka Univ. (Japan). School of Dentistry)

1981-12-01

347

A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (2)  

International Nuclear Information System (INIS)

This study is intended to improve scratch resistance of acrylic (hereafter called P.M.M.A.) molded products by first coating acrylic resin with well compatible cross-linking plastics of various kinds and, during the hardening stage, exposing them to radioactive irradiation to build up a hard coat to improve scratch resistance on the surface. From these studies, the following conclusions were reached. By the barrel test which considered scratches and abrasion caused by impacts against relatively hard objects as seen in biting resembling to the wet conditions in oral cavity, fairly well scratch resistance and abrasion resistance were obtained. These treatments give more effects to scratch resistance and abrasion resistance in the brushing conditions rather than in the striking against hard objects. For all specimen, scratch resistance and abrasion resistance in wet conditions can be expected to be three times greater than they are in dry conditions. (author).

1981-01-01

348

Cellular response to low Gamma-ray doses  

Energy Technology Data Exchange (ETDEWEB)

Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

Manzanares A, E.; Vega C, H.R.; Leon, L.C. de [Unidades Academicas de Estudios Nucleares, Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico)]. E-mail: emanz@cantera.reduaz.mx; Rebolledo D, O.; Radillo J, F. [Facultad de Ciencias Biologicas y Agropecuarias de la Universidad de Colima, Colima (Mexico)

2002-07-01

349

Cellular response to low Gamma-ray doses  

International Nuclear Information System (INIS)

Lymphocytes, obtained from healthy donors, were exposed to a low strength gamma-ray field to determine heat shock protein expression in function of radiation dose. Protein identification was carried out using mAb raised against Hsp70 and Hsc70.Hsp70 protein was detected after lymphocyte irradiation. In all cases, an increasing trend of relative amounts of Hsp70 in function to irradiation time was observed. After 1.25 c Gy gamma-ray dose, lymphocytes expressed Hsp70 protein, indicating a threshold response to gamma rays. (Author)

2002-01-01

350

Detection and confirmation of two novel mitochondrial DNA deletions in human lymphoblastoid cell line irradiated by 60Co gamma rays  

International Nuclear Information System (INIS)

Objective: To screen the radiation induced mitochondtial DNA (mtDNA) deletion and confirm it. Methods: Long-range PCR with two pairs of primers, which could amplify the whole human mitochondrial genome, was used to analyze the lymphoblastoid cell line before and after exposed to 10 Gy 60Co ?-rays. The limited condition PCR was used to certify the possible mtDNA deletion shown by long-range PCR. The PCR products were purified, cloned, sequenced and the sequence results were BLASTed. Results: The predicted bands of mtDNA were observed on the control cell lines, and the possible mtDNA deletions were also detected on the irradiated cell lines. The deletions were certified by the limited condition PCR. The sequence BLAST results of the cloned PCR products showed that there were two kinds of deletions, 7455 bp deletion (nt475-7929 in heavy strand) and 9225 bp deletion (nt7714-369 in heavy strand), which were both results from 8 bp direct repeats. Further bioinformatics analysis showed that the two deletions were novel deletions. Conclusions: Ionizing radiation could induce the 7455 bp and 9225 bp deletions in human lymphocytes. (authors)

2008-01-01

351

Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes  

CERN Document Server

Terrestrial Gamma-Ray Flashes (TGFs) are very short bursts of high energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mini-Calorimeter. We detect 8 TGFs with gamma-ray photons of energies above 20 MeV localized by the AGILE gamma-ray imager with an accuracy of 5-10 degrees at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the sub-satellite point than 400 km. Considering that our gamma rays reach the AGILE satellite at 540 km altitude with limited scattering or attenuation, our measurements provide the first precise direct localization of TGFs from space.

Marisaldi, M; Trois, A; Giuliani, A; Tavani, M; Labanti, C; Fuschino, F; Bulgarelli, A; Longo, F; Barbiellini, G; Del Monte, E; Moretti, E; Trifoglio, M; Costa, E; Caraveo, P; Cattaneo, P W; Chen, A; D'Ammando, F; De Paris, G; Di Cocco, G; Di Persio, G; Donnarumma, I; Evangelista, Y; Feroci, M; Ferrari, A; Fiorini, M; Froysland, T; Galli, M; Gianotti, F; Lapshov, I; Lazzarotto, F; Lipari, P; Mereghetti, S; Morselli, A; Pacciani, L; Pellizzoni, A; Perotti, F; Picozza, P; Piano, G; Pilia, M; Prest, M; Pucella, G; Rapisarda, M; Rappoldi, A; Rubini, A; Sabatini, S; Soffitta, P; Striani, E; Vallazza, E; Vercellone, S; Vittorini, V; Zambra, A; Zanello, D; Antonelli, L A; Colafrancesco, S; Cutini, S; Giommi, P; Lucarelli, F; Pittori, C; Santolamazza, P; Verrecchia, F; Salotti, L; 10.1103/PhysRevLett.105.128501

2010-01-01

352

Reaction mechanisms in ? irradiated high surface silica-elastomer systems  

International Nuclear Information System (INIS)

[en] Complete text of publication follows. In this work the mechanism of the ?-ray induced vulcanization of the binary systems consisting of styrene butadiene rubber (SBR; 30% stryrene, 25% vinyl units) and high surface silica (160-1000 m2/g) are investigated by matrix EPR spectroscopy, ATR-FTIR and by measuring the crosslinking kinetics. The experiments have dealt with pristine silica, silica modified by radiation grafting of polybutadiene olygomers (SiO2/PB) and the SBR compounds containing 30-40% of pristine or modified silica. The irradiation under vacuum of the pristine silica gives rise to thermally unstable species which decay at very low temperature, below 180 K. When the SBR/silica compounds are irradiated, in addition to the SBR radicals, also SBR chain radicals is greatly enhanced when using silica coated with polybutadiene olygomers bearing high (25-45%) vinyl double bond content. The rationale of such observation is that the species generated within the bulk of the silica particles migrate to the surface where are scavenged by the vinyl double bonds of the absorbed chains. It is thus assessed that the direct radiolysis of silica plays an active role in the radiation vulcanization process by promoting the formation of silica-rubber chemical links which are of key importance in the reinforcement mechanism. The crosslinking kinetics were found to be coherent with the above observation showing that the crosslinks yield vs dose ratios increase in the order: pure SBR 2 2(PB).

2011-09-01

353

Thermal properties of irradiated ethylene-propylene copolymers  

Energy Technology Data Exchange (ETDEWEB)

Samples of crude ethylene-propylene copolymers, of the elastomer types EPDM and EPR, were prepared by solvent removal from polymer solutions. The EPDM contained 3.5% ethylidene norbornene. Samples of the elastomers were irradiated with gamma rays to different absorbed doses in the range 50-1000kGy. Specific heat capacity measurements were made over the temperature range 330-430K for each absorbed dose. Oxygen uptake determinations were also made. The observations and the difference in behaviour between the elastomers are explained in terms of free radical recombination, crosslinking and scission. (UK).

Zaharescu, T. [ICPE SA, Bucharest (Romania); Meltzer, V.; Vilcu, R. [Bucharest Univ. (Romania). Faculty of Chemistry

1996-07-15

354

Very high energy gamma rays from gamma ray bursts  

International Nuclear Information System (INIS)

[en] Very high energy gamma rays from gamma ray bursts are explained by the expanding fireball model. The high energy gamma ray generation efficiency, the relativistic effect, and the absorption in cosmic background radiation are taken into account. It is shown that the ejection of gamma rays with the energies higher than 10 GeV may happen at the very beginning of the fireball expansion ?10-5 s with a fluence up to 10-4-10-6 cm-2 arriving at the earth

2003-01-01

355

Secondary gamma-ray measurements  

International Nuclear Information System (INIS)

Secondary gamma-ray measurements were carried out on the D-T neutron skyshine experiments at FNS by opening the skyshine experimental port at the roof. The Gamma-ray was measured with NaI(Tl) scintillation detectors as far as 300 m away from the D-T target point. The Gamma-ray dose rates were evaluated from the gamma-ray spectra unfolded from the pulse height distribution of the NaI(Tl) scintillation detectors, which agreed well to the Monte Carlo simulation using MCNP-4B code within 20%. Source nuclei of the gamma-rays were investigated around the FNS facility by using a high purity Ge detector, where capture gamma-rays of iron, hydrogen and silicon were identified. The origin of the iron capture gamma-rays is considered to be the concrete of the building. Also gamma-rays of hydrogen and silicon were observed, which suggests that the major source of secondary gamma-rays are from capture reactions of the skyshine neutrons in the soil rather than from scattering reactions in the air. (author)

2004-01-01

356

Gamma ray irradiation effects on the optical properties of BaO–Na2O–B2O3–SiO2 glasses  

Science.gov (United States)

Gamma ray effects on the optical spectra of the barium borosilicate glasses have been studied.Changes in optical band gap and Urbach energy have been calculated.The results indicate that BaO enhances the radiation shielding properties of the glass.

Kaur, Ravneet; Singh, Surinder; Pandey, O. P.

2013-09-01

357

An Elementary Treatment of Gamma-Ray Heating and Gamma-Ray Dosage in Inhomogeneous Reactors  

International Nuclear Information System (INIS)

An analysis is made of the heat produced by the absorption of gamma rays in a sample placed into a reactor. It is clearly shown that enormous local (space) variations in gamma flux exist in current reactors. An application to the Hanford reactors is treated in some detail. Although the estimates obtained may be good to but a factor of two, it is clearly shown that in most cases the major portion of the heating is due to (n, ?) reactions within the sample itself, and in some cases to the gamma rays generated in liners and cans, and not from the gamma rays generated in fission, nor from the moderator. Some implications of these results are discussed, among the most important being their application to radiation chemistry in reactors. Several mathematical results for absorption and generation of gamma rays in various bodies which should be useful in estimating dosage rates for samples irradiated in reactors are given (Appendix II). A method for making the calculations for an arbitrary absorption law are given (Appendix III). This method may be used with the true absorption law for gamma rays or even for the calculation of the absorption of the energy of particles possessing a range law of absorption, e.g., ?-rays or protons.

1952-01-01

358

Gamma rays induced genetic variability in bougainvillea  

International Nuclear Information System (INIS)

Stem cuttings of 20 cultivars of Bougainvillea belonging to different group, bract colour and type were irradiated with 500 and 750 rad and 1.0, 1.25, 1.75 and 2.25 krad of gamma rays. Reduction in sprouting, plant height and survival were recorded after irradiation in most of the cultivars. Stimulation in all these characters were also recorded in some cultivars at lower doses. Different types of morphological abnormalities in leaves were recorded after irradiation in all the cultivars. Somatic mutations in leaves (chlorophyll variegation) and bract colour were recorded in the present experiment. (author)

2002-01-01

359

Gamma-ray dosimetry errors with TLDs  

International Nuclear Information System (INIS)

[en] Gamma-ray dosimetry errors can occur when thermoluminescence dosimeters (TLDs) are irradiated in thin-walled containers. An overresponse for LiF TLDs, irradiated by an isotropic source, of approximately 25% for 24Na; 20% for 60Co, and 2% for 137Cs was observed. The overresponse for CaF2 TLDs was found to be less than the overresponse of LiF TLDs. Underresponse errors can occur for TLDs in thin-walled containers irradiated under narrow-beam geometry conditions because electron equilibrium is not established, but this error is well known and is not discussed

1977-12-09

360

Gamma ray detector  

Energy Technology Data Exchange (ETDEWEB)

A gamma-ray detector comprises a scintillation crystal (e.g. BaF[sub 2]), a gas for converting u.v. radiation generated by the crystal into electric charge carriers and a detector to detect the charge carriers, a gap being provided between the scintillation means and the detector which contains a gate electrode to inhibit the passage of charge carriers. There are also a pair of amplifying gaps to enhance the electron yield of the gas. A further reverse-biased gap may be positioned adjacent to the crystal to prevent charge build-up thereon. Shield electrodes prevent gate switching signals causing spurious responses in the detector circuit. (author).

Bateman, J.E.; Stephenson, R.

1993-05-05

 
 
 
 
361

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

Energy Technology Data Exchange (ETDEWEB)

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

Kagimoto, Akio

1987-01-01

362

Monte Carlo calculations of doses to tiles irradiated by 60Co and 252Cf simulating atomic bomb gamma-ray fluences.  

UK PubMed Central (United Kingdom)

Dose calculations for tiles exposed to the Hiroshima atomic bomb radiations were undertaken. A Monte Carlo code, ABOMB, was developed which considers the characteristics of atomic bomb gamma-ray fluences and geometrical configurations. ABOMB was applied to tile dose calculations for the available photon sources with definite fluences. Its validity was tested by comparing the depth-dose curves calculated for 60Co and 252Cf beams with the equivalent experimental data obtained in the laboratory. Selection of parameters, contribution of backscattering, and computing time also were considered. Present calculations are considered to be accurate with uncertainties less than +/- 10%, and may be useful for correcting or reinforcing atomic bomb gamma-ray doses, together with tile dose measurements by thermoluminescent (TL) dosimetry.

Uehara S; Hoshi M; Sawada S; Nagatomo T; Ichikawa Y

1988-03-01

363

Monte Carlo calculations of doses to tiles irradiated by 60Co and 252Cf simulating atomic bomb gamma-ray fluences  

Energy Technology Data Exchange (ETDEWEB)

Dose calculations for tiles exposed to the Hiroshima atomic bomb radiations were undertaken. A Monte Carlo code, ABOMB, was developed which considers the characteristics of atomic bomb gamma-ray fluences and geometrical configurations. ABOMB was applied to tile dose calculations for the available photon sources with definite fluences. Its validity was tested by comparing the depth-dose curves calculated for /sup 60/Co and /sup 252/Cf beams with the equivalent experimental data obtained in the laboratory. Selection of parameters, contribution of backscattering, and computing time also were considered. Present calculations are considered to be accurate with uncertainties less than +/- 10%, and may be useful for correcting or reinforcing atomic bomb gamma-ray doses, together with tile dose measurements by thermoluminescent (TL) dosimetry.

Uehara, S.; Hoshi, M.; Sawada, S.; Nagatomo, T.; Ichikawa, Y.

1988-03-01

364

Monte Carlo calculations of doses to tiles irradiated by 60Co and 252Cf simulating atomic bomb gamma-ray fluences  

International Nuclear Information System (INIS)

Dose calculations for tiles exposed to the Hiroshima atomic bomb radiations were undertaken. A Monte Carlo code, ABOMB, was developed which considers the characteristics of atomic bomb gamma-ray fluences and geometrical configurations. ABOMB was applied to tile dose calculations for the available photon sources with definite fluences. Its validity was tested by comparing the depth-dose curves calculated for 60Co and 252Cf beams with the equivalent experimental data obtained in the laboratory. Selection of parameters, contribution of backscattering, and computing time also were considered. Present calculations are considered to be accurate with uncertainties less than +/- 10%, and may be useful for correcting or reinforcing atomic bomb gamma-ray doses, together with tile dose measurements by thermoluminescent (TL) dosimetry.

1988-01-01

365

Estimating. gamma. -rays dose using computer  

Energy Technology Data Exchange (ETDEWEB)

When gum arabic is exposed to {gamma}-rays, a change in its reflection and absorption ability for the different wave lengths is obtained. This change is used for estimating the absorbed {gamma}-rays directly. In the present work we are not concerned with the type of components that are chemically formed as emphasis will only be put on the physical changes. The physical state is taken as a potential chemical change since a molecular damage is accumulated as a result of the dose absorbed. The fortran IV data General (Nova 3) designed for estimating colour measurements was connected to a spectrophotometer that enables measuring the changes in both absorbing and reflecting or even diffusing of light through irradiated materials. (author).

Al-Rawi, A.M.; Muslih, R.M.; Al-Harithy, R.S. (Baghdad Univ. (Iraq). Coll. of Education for Women)

1990-01-01

366

Application for plasma diagnostics with D(?, ?)6Li gamma-ray  

International Nuclear Information System (INIS)

[en] The gamma ray measurement from fusion plasma is one of the important techniques to clarify fast ion properties in plasma. Some observation of the gamma-ray in JET plasma was reported. 12C(d, p?)13C and 9Be(?, n?)12C reactions on the JET observation are mainly recommended as the actual prospective nuclear reaction on the gamma-ray measurement. However, it is thought that the gamma-ray observation by means of these reactions significantly depends on the conditioning (i.e. densities of the beryllium and carbon in plasma). Therefore, it is also important to examine the availabilities concerning the methods of gamma ray. We have tried to measure the 2.18 MeV gamma ray of D(?, ?)6Li reaction and the properties of the another gamma ray emission by MeV-He++ beam irradiation experiment. (author)

2006-01-01

367

Application for Plasma Diagnostics with D(?,?)6Li Gamma-ray  

International Nuclear Information System (INIS)

University Introduction The gamma ray measurement from fusion plasma is one of the important techniques to clarify fast ion properties in plasma. Some observation of the gamma-ray in JET plasma was reported. 12C(d,p ?)13C and 9Be(a,n ?)12C reactions on the JET observation are mainly recommended as the actual prospective nuclear reaction on the gamma-ray measurement. However, it is thought that the gamma-ray observation by means of these reactions significantly depends on the conditioning (i.e. densities of the beryllium and carbon in plasma). Therefore, it is also important to examine the availabilities concerning the methods of gamma ray. We have tried to measure the 2.18 MeV gamma ray of D(?,?)6Li reaction and the properties of the another gamma ray emission by MeV-He++ beam irradiation experiment. (author)

2006-01-01

368

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-12-31

369

Gamma ray observation from ground  

Energy Technology Data Exchange (ETDEWEB)

Nowadays the Gamma ray observation of the sky is opening an important window to understand the nature of high-energy phenomena in the Universe and provides important tools to test fundamental physics that is constrained in the production and propagation of high-energy photons. The observation of gamma ray from ground is playing an important role: the success of the running ground based experiments shows that the large collection area and the high sensitivity to the high energy domains makes the gamma ray observation from ground complementary to the satellite one, and in many cases fundamental for a large class of scientific investigation. In this paper the main ground based gamma ray running experiment are reviews and a glance of the perspective in this field is given.

Mariotti, M, E-mail: mariotti@pd.infn.i [Dipartimento di Fisica dell' Universita di Padova, via F. Marzolo 8, I-35131 Padova (Italy)

2010-01-01

370

Gamma ray observation from ground  

International Nuclear Information System (INIS)

[en] Nowadays the Gamma ray observation of the sky is opening an important window to understand the nature of high-energy phenomena in the Universe and provides important tools to test fundamental physics that is constrained in the production and propagation of high-energy photons. The observation of gamma ray from ground is playing an important role: the success of the running ground based experiments shows that the large collection area and the high sensitivity to the high energy domains makes the gamma ray observation from ground complementary to the satellite one, and in many cases fundamental for a large class of scientific investigation. In this paper the main ground based gamma ray running experiment are reviews and a glance of the perspective in this field is given.

2010-01-01

371

Gamma rays at airplane altitudes  

Energy Technology Data Exchange (ETDEWEB)

An examination of the gamma ray flux above 1 TeV in the atmosphere is needed to better understand the anomalous showers from point sources. Suggestions are made for future experiments on board airplanes.

Iwai, J.; Koss, T.; Lord, J.; Strausz, S.; Wilkes, J.; Woosley, J. (University of Washington, Seattle, WA 98195 USA (US))

1990-03-20

372

Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy; Biodegradacao de poliuretano derivado de oleo vegetal irradiado com raios gama 25 kGy e 100 kGy  

Energy Technology Data Exchange (ETDEWEB)

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

Santos, Antonia M. dos, E-mail: amsantos@rc.unesp.br [Universidade Estadual Paulista - Unesp, Rio Claro, SP (Brazil); Claro Neto, Salvador [Universidade de Sao Paulo - USP, Campus de Sao Carlos, SP (Brazil); Azevedo, Elaine C. de [Universidade Federal do Parana, Campus de Curitiba, PR (Brazil)

2011-07-01

373

FFTF shield and gamma ray measurements  

International Nuclear Information System (INIS)

An extensive measurements program was carried out prior to routine operation of the Fast Flux Test Facility (FFTF) to establish (1) the attenuation characteristics of the reactor shield, (2) the nuclear environment in the core, and (3) to assure that the facility could be operated safely from the standpoint of radiological considerations. Reactor shield neutron fluxes were measured primarily using radioactivant detectors irradiated in special test vehicles placed at accessible locations. Preliminary evaluation of the data indicates shield performance consistent with design calculations. Gamma ray measurements employed a variety of ionization chambers and calorimeters as well as thermoluminescent dosimeters, self-powered gamma ray detectors, and thermal expansion difference temperature monitors. The gamma ray experimental results are consistent and also in relatively good agreement with analytical predictions. Plant shield surveys employed standard radiation survey instruments. Although several minor local shield deficiencies were discovered that required modification, no significant design or construction shortcomings were found and the facility is being operated at design power with the operating crews receiving negligible radiation doses. (author)

1983-01-01

374

Effects of post-treatment incubation on recombinogenesis in incision-proficient and incision-deficient strains of saccharomyces cerevisiae, 1; Recombinogenesis after UV- and. gamma. -ray-irradiation  

Energy Technology Data Exchange (ETDEWEB)

After UV-irradiation of G1 phase cells, most gene conversion and crossing-over took place in cells of incision-proficient strains without post-irradiation incubation. In contrast, incision-deficient cells markedly induced both of these recombinational events only after irradiated cells were incubated for several hours in liquid growth medium before selection. These results indicate that when G1 cells are irradiated with UV recombinational events are initiated during that G1 phase in incision-proficient strains; whereas, they are not initiated in irradiated incision-deficient strains before the cells reach the S/G2 phase. Experimental {gamma}-ray results also suggest that post-irradiation incubation is not required for incision-proficient and -deficient strains to initiate mitotic recombinational events. Taken together, these results show that the formation of incision nicks and of post-replication gaps in DNA appears to be necessary for the initiation of recombinational events after UV treatment; whereas, it is not required after {gamma}-irradiation. (author).

Saeki, Tetsuya; Machida, Isamu (National Inst. of Radiological Sciences, Chiba (Japan))

1991-12-01

375

Effect of gamma rays on single bracted bougainvilleas  

International Nuclear Information System (INIS)

Stem cuttings of five single bracted bougainvillea were irradiated with 250, 750 and 1500 rads of gamma rays. Reduction in sprouting, plant height and survival and increase in chromosomal aberration were recorded after irradiation in all the cultivars. Different types of morphological abnormalities in leaves including chlorophyll variegation were observed in the treated populations. (author)

1999-01-01

376

AGILE and gamma-ray astrophysics  

Energy Technology Data Exchange (ETDEWEB)

The study of {gamma} rays is fundamental for our understanding of the universe: {gamma} rays probe the most energetic phenomena occurring in nature, and several signatures of new physics are associated with the emission of {gamma} rays. The main science objectives and the status of the new generation high-energy gamma-ray astrophysics experiment AGILE are presented.

Longo, F.; Argan, A.; Auricchio, N.; Barbiellini, G.; Bulgarelli, A.; Caraveo, P.; Celesti, E.; Chen, A.; Cocco, V.; Costa, E.; Di Cocco, G.; Fedel, g.; Feroci, M.; Fiorini, M.; Froysland, T.; Galli, M.; Gianotti, F.; Giuliani, A.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Mauri, A.; Marisaldi, M.; Mereghetti, S.; Morelli, E.; Morselli, A.; Pacciani, L.; Paladin, F.; Pellizzoni, A.; Perotti, F.; Picozza, P.; Pittori, C.; Pontoni, C.; Porrovecchio, J.; Preger, B.; Prest, M.; Rapisarda, M.; Rossi, E.; Rubini, A.; Soffitta, P.; Tavani, M.; Traci, A.; Trifoglio, M.; Vallazza, E.; Vercellone, S.; Zanello, D

2003-09-01

377

Catalogue of gamma rays from radionuclides  

International Nuclear Information System (INIS)

A catalogue of almost 11000 gamma rays is presented. The gamma rays are sorted by energy. In addition to the gamma-ray intensity per 100 decays of the parent, the decay half-life and associated gamma rays are given. All data are from a computer processing of a recent ENSDF file. (author).

1983-01-01

378

Gamma ray induced chromophore modification of softwood thermomechanical pulp  

International Nuclear Information System (INIS)

This study focuses on bleaching a softwood (black spruce, balsam fur) thermomechanical pulp with gamma rays. Gamma rays are known for their enormous penetrating power, along with their ionizing properties. They can generate highly energetic radicals capable of oxidizing lignin chromophores. The authors studied the influence of isopropyl alcohol, sodium borohydride, oxygen, hydrogen peroxide, nitrogen dioxide and water along with gamma ray irradiation of the pulps. The authors measured the optimal dose and dose rate, along with the influence of the radical scavengers like oxygen on the bleaching effect of gamma irradiated pulps. They observe various degrees of bleaching of these pulps. Evidence relates this bleaching to the generation of perhydroxyl anions upon irradiation of water. Also, they were able to pinpoint the influence of the dose rate on the rate of formation and disappearance of these perhydroxyl anions and their influence on bleaching kinetics. Stability toward photoyellowing, and photoyellowing's kinetic of papers from these pulps was also studied.

1992-01-01

379

Modulated gamma ray beam absorptiometer  

International Nuclear Information System (INIS)

[en] The purpose of this paper is to describe the study and operating of a heavy elements content measuring instrument. This apparatus (French patent n0 2184533, December 16, 1974) uses the absorption of a modulated gamma ray beam to measure the concentration of 5 to 500 g per litre uranium of plutonium solutions with an over 1% accuracy. The activity of the fission products present in the solution may rise to 60 Ci/l. An automatic device suppresses all daily checkings and adjustements. The tension obtained is proportional to the content of the heavy element being measured. The influence of the nitric acid content is twenty times as weak as in the case of a conventional densimeter. This apparatus is particularly adapted to fuel reprocessing plants[fr] L'objet de cette publication est de decrire l'etude et la realisation d'un teneurmetre par absorption d'un faisceau gamma module. Cet appareil brevete (n0 2184533 du 16.12.1974) permet d'apres l'absorption d'un faisceau gamma, la mesure des concentrations d'uranium ou de plutonium en solution de 5 a 500 g/l, avec une precision meilleure que 1%. L'activite des produits de fission presents dans la solution peut atteindre 60 Ci/l. Un systeme de recalage automatique supprime toute intervention pour les controles et reglages. Les tensions delivrees sont directement proportionnelles aux teneurs de l'element lourd mesure. L'influence de la normalite en acide nitrique est 20 fois plus faible que dans le cas de l'utilisation d'un densimetre classique. Cet appareil est particulierement adapte aux usines de traitement des combustibles irradies

1979-01-01

380

Cosmic Gamma-Ray Spectroscopy  

CERN Multimedia

Gamma-ray instrumentation for astronomical spectroscopy consists of multiple-interaction detectors in space combined with sophisticated post-processing of detector events on ground. Spectral signatures in the MeV regime originate from transitions in the nuclei of atoms (rather than in their electron shell). Nuclear transitions are stimulated by either radioactive decays or high-energy nuclear collisions such as with cosmic rays. Gamma-ray lines have been detected from radioactive isotopes produced in nuclear burning inside stars and supernovae, and from energetic-particle interactions in solar flares. 56Ni directly reflects the source of supernova light. The paucity of corresponding 44Ti gamma-ray line sources reflects the variety of dynamical conditions herein. 26Al and 60Fe are dispersed in interstellar space from massive-star nucleosynthesis over millions of years. Gamma-rays from their decay are measured in detail by gamma-ray telescopes, astrophysical interpretations reach from massive-star interiors to ...

Diehl, Roland

2013-01-01

 
 
 
 
381

A neutron capture gamma-ray facility  

International Nuclear Information System (INIS)

[en] A neutron capture gamma-ray facility was constructed for prompt gamma-ray spectrometry, and its characteristics were measured. In the facility, a neutron beam is extracted from the H-6 horizontal experimental hole of Japan Research Reactor No.3, JAERI, and a target outside the reactor is irradiated by the beam. Thermal neutron flux at the target position was 8.0 x 107 n/cm2.s and the cadmium ratio (Au) was 21. Characteristics of a Ge gamma-ray spectrometer using a 7 in. diameter x 8 in. length guard NaI (Tl) detector were measured for 3 modes, single, Compton (escape) suppressed and pair, with neutron capture gamma-rays from nitrogen, chromium etc. Characteristics were: (1) in single spectrometer, full-energy peak efficiency 2.3 x 10-5 (1