WorldWideScience
1

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

CERN Document Server

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

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

2005-01-01

2

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-02-07

3

Gamma ray irradiation for sludge solubilization and biological nitrogen removal  

Science.gov (United States)

This study was conducted to investigate the effects of gamma ray irradiation on the solubilization of waste sewage sludge. The recovery of an organic carbon source from sewage sludge by gamma ray irradiation was also studied. The gamma ray irradiation showed effective sludge solubilization efficiencies. Both soluble chemical oxygen demand (SCOD) and biochemical oxygen demand (BOD 5) increased by gamma ray irradiation. The feasibility of the solubilized sludge carbon source for a biological nitrogen removal was also investigated. A modified continuous bioreactor (MLE process) for a denitrification was operated for 20 days by using synthetic wastewater. It can be concluded that the gamma ray irradiation was useful for the solubilization of sludge and the recovery of carbon source from the waste sewage sludge for biological nitrogen removal.

Kim, Tak-Hyun; Lee, Myunjoo; Park, Chulhwan

2011-12-01

4

Pulse gamma ray generation and irradiation facility development  

Energy Technology Data Exchange (ETDEWEB)

The irradiation dose of pulse type can be obtained by linear electron accelerator. In order to obtain the high radiation dose, the high energy and current facility of LINAC are used by the irradiation equipment. The dose analysis for pulse type irradiation condition is introduced by MCNP 5c code. Target material is used by tungsten plate to generate secondary gamma ray by electron beam. By using the analysis results, the irradiation equipment for gamma ray generation is designed and fabricated.

Lee, Byung Chul

2012-07-15

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.)

6

Inactivation of citrus tristeza virus by gamma ray irradiation  

International Nuclear Information System (INIS)

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

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

Gamma ray irradiation to semi-purified diet  

International Nuclear Information System (INIS)

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

9

Thermal decomposition of ammonium perchlorate during gamma-ray irradiation  

International Nuclear Information System (INIS)

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

10

Influence of gamma ray irradiation on metakaolin based sodium geopolymer  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-11-15

11

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

OpenAIRE

Hanafiah DS, Trikoesoemaningtyas, Yahya S, Wirnas D. 2010. Induced mutations by gamma ray irradiation to Argomulyo soybean (Glycine max) variety. Nusantara Bioscience 2: 121-125. Induced mutation by gamma ray irradiation is one way to increase genetic variability of plants. This research used gamma ray irradiation on low doses (micro mutation). The aim of this research was to know the respons of doses level by micro mutation on gamma ray irridation to the growing and development of Argomulyo ...

DESTA WIRNAS; SUDIRMAN YAHYA; TRIKOESOEMANINGTYAS; DIANA SOFIA HANAFIAH

2010-01-01

12

Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation  

OpenAIRE

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 neu...

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

2002-01-01

13

Apoptosis and necrosis in testes irradiated with gamma rays  

International Nuclear Information System (INIS)

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

14

Thermoluminescence of Simulated Interstellar Matter after Gamma-ray Irradiation  

CERN Document Server

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

15

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)

16

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

17

Influence of gamma-ray irradiation on stress corrosion cracking of austenitic stainless steels  

International Nuclear Information System (INIS)

Stress corrosion cracking (SCC) was studied in boiling deionized water with gamma-ray irradiation using double U-bend specimens of sensitized austenitic stainless steels, which were considered as canister materials for high level radioactive waste. Gamma-ray irradiation accelerated extremely intergranular SCC in Type 304 ss and Type 304L ss, while Type 304ELC ss did not crack even if irradiated with gamma-ray. Electrochemical measurements revealed that SCC should have been accelerated by oxidizing agents which were generated by radiolysis of water under gamma-ray irradiation

18

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 6060Co, 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)

19

Bacteriostatic activity of various antibiotics after gamma-ray irradiation  

International Nuclear Information System (INIS)

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

20

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)

21

Genetic studies on two soybean cultivars irradiated with gamma rays  

International Nuclear Information System (INIS)

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

22

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

International Nuclear Information System (INIS)

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

23

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

24

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

International Nuclear Information System (INIS)

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

25

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-03-15

26

Semiconductor quantum dot scintillation under gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

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

Letant, S E; Wang, T

2006-08-23

27

Cesium adsorption ability and stability of metal hexacyanoferrates irradiated with gamma rays  

International Nuclear Information System (INIS)

The cesium (Cs) adsorption ability and stability of metal hexacyanoferrates (MHCFs: M = Fe, Cu, Ni) in HNO3 solutions were investigated as a function of the absorbed dose resulting from irradiation with gamma rays. (author)

28

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

OpenAIRE

The paper investigates a possibility of pMOS dosimeter re-use for the measurement of gamma-ray irradiation. The dosimeters were irradiated to the dose of 35 Gy, annealed at room and elevated temperatures, after which they were irradiated again to the same dose value. Changes in the threshold voltage shift during those processes were followed, and it was shown that their re-use depends on a gate polarization during irradiation. For the gate polarization of 5 V during irradiation the pMOS...

Pejovi? Mili? M.; Pejovi? Mom?ilo M.; Jakši? Aleksandar B.; Stankovi? Koviljka ?.; Markovi? Slavoljub A.

2012-01-01

29

In-pile gamma-ray spectrometry to follow OSIRIS irradiations  

International Nuclear Information System (INIS)

A description is given of a gamma-ray spectrometry facility located in the immediate proximity of the OSIRIS reactor core. This device is used to examine nuclear fuel elements in loop or rig throughout the period of irradiation, with no more than a few minutes required to transfer the fuel from the irradiation point to the measurement bench. This internal reactor gamma-ray spectrometry device of original design eliminates corrections for radioactivity decrease and avoids any risk of overlooking relevant data.

30

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

OpenAIRE

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

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

2014-01-01

31

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

32

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

Directory of Open Access Journals (Sweden)

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

DESTA WIRNAS

2010-11-01

33

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

International Nuclear Information System (INIS)

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

34

Gamma ray irradiated AgFeO2 nanoparticles with enhanced gas sensor properties  

Science.gov (United States)

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

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

2014-11-01

35

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

International Nuclear Information System (INIS)

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

36

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

International Nuclear Information System (INIS)

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

37

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

International Nuclear Information System (INIS)

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

38

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

Energy Technology Data Exchange (ETDEWEB)

Influence of the irradiation on the corrosion behavior of stainless steel (type 304ULC) in boiling nitric acid solution was examined by using {sup 60}Co {gamma}-ray source. It was found from the experimental results that radiolysis products of nitric acid (NO{sub x}, HNO{sub 2}) resulted from the {gamma}-ray irradiation made the environment in the bulk solution more reducing one. On the other hand, corrosion rate of 304ULC was slightly enhanced by the irradiation, which being trivial from the engineering viewpoint. From the result of an AC impedance measurement, this corrosion enhancement was inferred as caused by an enhancement in the current across the passive film by the {gamma}-ray irradiation on the stainless steel surfaces. (author)

Nagai, Takayuki; Takeuchi, Masayuki; Takeda, Seiichiro [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works; Yamamoto, T.A.; Tsukui, Shigeki; Okamoto, Shinichi

1998-07-01

39

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-11-15

40

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-08-01

41

Structure change of elastomer by irradiation, (3). The effect of ionizing radiation on Mooney-Rivlin plot of elastomer  

Energy Technology Data Exchange (ETDEWEB)

The changes of C/sub 1/ and C/sub 2/ of Mooney-Rivlin plot of elastomer by irradiation was studied. The sample used is tetrafluoroethylene-propylene copolymer. Scission reaction of the polymer chain is predominant when the diffusion of oxygen is sufficient enough during irradiation. On the other hand, irradiation without oxygen in the polymer increases the cross-linking density. The result for three cases are as follows: (1) Values of C/sub 1/ increase and that of C/sub 2/ decrease with increasing dose when the cross-linking density of the elastomer increase by irradiation. (2) Both C/sub 1/ and C/sub 2/ decreases with increasing dose when the irradiation causes a decrease in cross-linking density of the polymer. (3) The third case, where the cross-linking density was maintained the constant by the alternative irradiation of /gamma/ray (60 kGy) and electron beam (40 kGy). The operation (alternating irradiation) causes the same amount of scission and cross-linking in the polymer. C/sub 1/ increases slightly with increasing the times of operation and C/sub 2/ decreases with increasing the times of that. The result suggests that C/sub 2/ decreases with decreasing the effective long network chain by irradiation. (author).

Ito, Masayuki

1989-02-01

42

Morphological Changes of Polystyrene Sorbents after Gamma-Rays Irradiation.  

Czech Academy of Sciences Publication Activity Database

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

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

43

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)

44

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-11-15

45

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

46

Sterilization of commercial spices by gamma-ray irradiation and its effect to essencial oil  

International Nuclear Information System (INIS)

Eleven kinds of commercial spices were irradiated with gamma-ray at the dose of 0 to 5 kGy. The microbial counts of almost all the samples were decreased under 103/g by the dose of 5 kGy. The D10 value of microbials contaminated to these spices were 1.1 to 4.3. Five kGy of gamma-ray irradiation affected to the recoveries of essencial oil from the spices. The effect was varied between spices. While the recoveries from some spices were increased, the others were decreased. (author)

47

Tetraploid induction by gamma-ray irradiation in mulberry  

International Nuclear Information System (INIS)

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

48

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

49

Influence of irradiation upon few-layered graphene using electron-beams and gamma-rays  

International Nuclear Information System (INIS)

Few-layered graphene (FLG) is irradiated by electron beams and gamma rays. After 100?keV electron irradiation, the edges of FLG start bending, shrinking, and finally generate gaps and carbon onions due to sputtering and knock-on damage mechanism. When the electron beam energy is increased further to 200?keV, FLG suffers rapid and catastrophic destruction. Unlike electron irradiation, Compton effect is the dominant damage mechanism in gamma irradiation. The irradiation results indicate the crystallinity of FLG decreases first, then restores as increasing irradiation doses, additionally, the ratio (O/C) of FLG surface and the relative content of oxygen groups increases after irradiation.

50

Influence of irradiation upon few-layered graphene using electron-beams and gamma-rays  

Science.gov (United States)

Few-layered graphene (FLG) is irradiated by electron beams and gamma rays. After 100 keV electron irradiation, the edges of FLG start bending, shrinking, and finally generate gaps and carbon onions due to sputtering and knock-on damage mechanism. When the electron beam energy is increased further to 200 keV, FLG suffers rapid and catastrophic destruction. Unlike electron irradiation, Compton effect is the dominant damage mechanism in gamma irradiation. The irradiation results indicate the crystallinity of FLG decreases first, then restores as increasing irradiation doses, additionally, the ratio (O/C) of FLG surface and the relative content of oxygen groups increases after irradiation.

Wang, Yuqing; Feng, Yi; Mo, Fei; Qian, Gang; Chen, Yangming; Yu, Dongbo; Wang, Yang; Zhang, Xuebin

2014-07-01

51

Influence of irradiation upon few-layered graphene using electron-beams and gamma-rays  

Energy Technology Data Exchange (ETDEWEB)

Few-layered graphene (FLG) is irradiated by electron beams and gamma rays. After 100?keV electron irradiation, the edges of FLG start bending, shrinking, and finally generate gaps and carbon onions due to sputtering and knock-on damage mechanism. When the electron beam energy is increased further to 200?keV, FLG suffers rapid and catastrophic destruction. Unlike electron irradiation, Compton effect is the dominant damage mechanism in gamma irradiation. The irradiation results indicate the crystallinity of FLG decreases first, then restores as increasing irradiation doses, additionally, the ratio (O/C) of FLG surface and the relative content of oxygen groups increases after irradiation.

Wang, Yuqing; Feng, Yi, E-mail: fyhfut@163.com; Mo, Fei; Qian, Gang; Chen, Yangming; Yu, Dongbo; Wang, Yang; Zhang, Xuebin [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China)

2014-07-14

52

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

OpenAIRE

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

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

2011-01-01

53

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

CERN Document Server

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

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

2003-01-01

54

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

Czech Academy of Sciences Publication Activity Database

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

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

2010-01-01

55

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

International Nuclear Information System (INIS)

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

56

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

Directory of Open Access Journals (Sweden)

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

Pejovi? Mili? M.

2012-01-01

57

Gamma-Ray Irradiation and Contact with High-Alkalinity Sludge: Stability Studies of Mercury Fulminate  

International Nuclear Information System (INIS)

The stability of mercury fulminate under gamma-ray irradiation and in a high-alkalinity sludge environment was determined. Both differential scanning calorimetry and Fourier transform infrared spectroscopy were used to characterize mercury fulminate. Mercury fulminate completely decomposed in a gamma-ray source (0.86 Mrad/h) after a dose of 208 Mrad. This exposure equates to ?2.4 to 4 yr in Savannah River Site tanks. Mercury fulminate decomposed in contact with high-alkalinity wet sludge. This study suggests that any mercury fulminate or closely related energetic species decomposed long ago if it ever formed in the tank farm

58

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

International Nuclear Information System (INIS)

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

59

Structure change of elastomer by irradiation, (3)  

International Nuclear Information System (INIS)

The changes of C1 and C2 of Mooney-Rivlin plot of elastomer by irradiation was studied. The sample used is tetrafluoroethylene-propylene copolymer. Scission reaction of the polymer chain is predominant when the diffusion of oxygen is sufficient enough during irradiation. On the other hand, irradiation without oxygen in the polymer increases the cross-linking density. The result for three cases are as follows: (1) Values of C1 increase and that of C2 decrease with increasing dose when the cross-linking density of the elastomer increase by irradiation. (2) Both C1 and C2 decreases with increasing dose when the irradiation causes a decrease in cross-linking density of the polymer. (3) The third case, where the cross-linking density was maintained the constant by the alternative irradiation of ?ray (60 kGy) and electron beam (40 kGy). The operation (alternating irradiation) causes the same amount of scission and cross-linking in the polymer. C1 increases slightly with increasing the times of operation and C2 decreases with increasing the times of that. The result suggests that C2 decreases with decreasing the effective long network chain by irradiation. (author)

60

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-01-20

61

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

International Nuclear Information System (INIS)

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

62

Endurance of cultured pearls irradiated with gamma-rays  

International Nuclear Information System (INIS)

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

63

Chromosomal integrity of freeze-dried mouse spermatozoa after {sup 137}Cs {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

This study demonstrated that freeze-dried mouse spermatozoa possess strong resistance to {sup 137}Cs {gamma}-ray irradiation at doses of up to 8 Gy. Freeze-dried mouse spermatozoa were rehydrated and injected into mouse oocytes with an intracytoplasmic sperm injection (ICSI) technique. Most oocytes can be activated after ICSI by using spermatozoa irradiated with {gamma}-rays before and after freeze-drying. Sperm chromosome complements were analyzed at the first cleavage metaphase. Chromosome aberrations increased in a dose-dependent manner in the spermatozoa irradiated before freeze-drying. However, no increase in oocytes with chromosome aberrations was observed when fertilized by spermatozoa that had been irradiated after freeze-drying, as compared with freeze-dried spermatozoa that had not been irradiated. These results suggest that both the chromosomal integrity of freeze-dried spermatozoa, as well as their ability to activate oocytes, were protected from {gamma}-ray irradiation at doses at which chromosomal damage is found to be strongly induced in spermatozoa suspended in solution.

Kusakabe, Hirokazu [Department of Biological Sciences, Asahikawa Medical College, 2-1-1-1 Midorigaoka-higashi, Asahikawa 078-8510 (Japan)]. E-mail: hkusa55@asahikawa-med.ac.jp; Kamiguchi, Yujiroh [Department of Biological Sciences, Asahikawa Medical College, 2-1-1-1 Midorigaoka-higashi, Asahikawa 078-8510 (Japan)

2004-11-22

64

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

International Nuclear Information System (INIS)

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

65

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

Directory of Open Access Journals (Sweden)

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

Cappello Salvatore G.

2014-01-01

66

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.

67

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

Science.gov (United States)

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.

Salah, Numan; Habib, Sami S.; Khan, Zishan H.; Al-Hamedi, Salim; Djouider, Fathi

2009-11-01

68

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

69

Physico-chemical characterization of gamma rays irradiated crotamine  

International Nuclear Information System (INIS)

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

70

Physico-chemical characterization of gamma rays irradiated crotamine  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

71

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

International Nuclear Information System (INIS)

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

72

Low temperature gamma-ray irradiation effects on polymer materials  

International Nuclear Information System (INIS)

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

73

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

International Nuclear Information System (INIS)

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

74

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

International Nuclear Information System (INIS)

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

75

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-04-21

76

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

77

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

International Nuclear Information System (INIS)

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

78

Gamma-ray irradiation of a boreal forest ecosystem  

International Nuclear Information System (INIS)

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

79

Conductance of polypyrole irradiated with gamma rays to low doses  

Science.gov (United States)

In order to investigate the effect of gamma irradiation on the conductivity of polypyrrole, dc and ac conductivity measurements were carried out by four-probe technique as a function of temperature and by using Hall system at room temperature, respectively. Both ac and dc conductivities were found to exhibit a maximum at 1.80 kGy dose value. The dc conductivity of irradiated polypyrrole films was found to vary exponentially with (T) -1 at high temperature, while (T) -1/4 dependence was observed at low temperature range.

Ercan, i.?smail; Günal, i.?brahim; Güven, Olgun

1995-02-01

80

Conductance of polypyrole irradiated with gamma rays to low doses  

International Nuclear Information System (INIS)

In order to investigate the effect of gamma irradiation on the conductivity of polypyrrole, dc and ac conductivity measurements were carried out by four-probe technique as a function of temperature and by using Hall system at room temperature, respectively. Both ac and dc conductivities were found to exhibit a maximum at 1.80 kGy dose value. The dc conductivity of irradiated polypyrrole films was found to vary exponentially with (T)-1 at high temperature, while (T)-1/4 dependence was observed at low temperature range. (Author)

81

Conductance of polypyrole irradiated with gamma rays to low doses  

Energy Technology Data Exchange (ETDEWEB)

In order to investigate the effect of gamma irradiation on the conductivity of polypyrrole, dc and ac conductivity measurements were carried out by four-probe technique as a function of temperature and by using Hall system at room temperature, respectively. Both ac and dc conductivities were found to exhibit a maximum at 1.80 kGy dose value. The dc conductivity of irradiated polypyrrole films was found to vary exponentially with (T){sup -1} at high temperature, while (T){sup -1/4} dependence was observed at low temperature range. (Author).

Ercan, I.; Gueven, O. [Ankara Nuclear Research and Training Center (Turkey); Guenal, I. [Middle East Technical Univ., Ankara (Turkey)

1995-10-01

82

Gamma-ray spectra of neutron-irradiated activation detectors  

International Nuclear Information System (INIS)

The gamma spectra are presented of a set of activation detectors used by the reporting laboratory for neutron spectra measurements and irradiated in the core of zero-power light water reactor SR-0. The gamma spectra were measured by a semiconductor Ge-Li detector and a NaI(Tl) scintillation detector. (author)

83

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

Science.gov (United States)

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

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

1986-01-01

84

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

85

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

86

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

OpenAIRE

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

Pejovi? Mili? M.

2013-01-01

87

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

International Nuclear Information System (INIS)

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

88

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

89

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-04-15

90

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

International Nuclear Information System (INIS)

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

91

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

International Nuclear Information System (INIS)

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

92

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)

93

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

Science.gov (United States)

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

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

2009-11-01

94

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

Science.gov (United States)

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

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

2009-11-21

95

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

International Nuclear Information System (INIS)

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

96

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

International Nuclear Information System (INIS)

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

97

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

International Nuclear Information System (INIS)

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

98

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

International Nuclear Information System (INIS)

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

99

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

International Nuclear Information System (INIS)

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

100

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

Energy Technology Data Exchange (ETDEWEB)

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

Yamamoto, Takao [Osaka Univ., Suita (Japan); Tsukui, Shigeki; Okamoto, Shinichi; Nagai, Takayuki; Takeuchi, Masayuki; Takeda, Seiichiro; Tanaka, Yasumasa

1998-05-01

101

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

102

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

International Nuclear Information System (INIS)

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

103

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

104

Fractionated Irradiation of Mice with Fission Neutrons and Co60 Gamma Rays  

International Nuclear Information System (INIS)

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

105

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

Science.gov (United States)

The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

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

1991-01-01

106

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

International Nuclear Information System (INIS)

Three-year-old Yabukita and Yamakai tea trees were irradiated with 60Co gamma ray of total dose of 2kr, 4kr and 6kr (0.8 kr/hr) on March 23, 1972. The new leaves of non-irradiated plants and those irradiated with 2kr were picked on April 26 and June 2, respectively. The trees irradiated with larger doses did not develop new leaves. Mature leaves were collected on June 16. The leaves, dried and powdered, were analyzed for their components. The irradiation increased the amino acids in the new leaves of both varieties to about twice as compared with that of the no-treatment control. In the mature leaves, the amino acid content was increased with the radiation dose up to 4 kr, but at 6 kr, it was decreased slightly. In both new and mature leaves, the gamma-ray radiation decreased the content of serine and glutamic acid. The content of theanine in the new leaves was increased by radiation, but that in the mature leaves tended to decrease both with the increase of the radiation dose. The new leaves of both varieties irradiated with 2 kr contained slightly more tannin than the controls. It was thought that the delay of picking in case of the irradiated trees caused the difference in the new leaves. In the mature leaves, the content of tannin tended to decrease with the increasing radiation dose. The content of chlorophyll a was lower in the new leaves of irradiated Yabukita, but the contents of chlorophylls a and b in the mature leaves and of chlorophyll b in the mature leaves and of chlorophyll b in the new leaves tended to be higher than those of the controls. The radiation increased the concentration of both chlorophylls a and b in the new and mature leaves of Yamakai. The leaves of both varieties after the irradiation showed smooth surfaces. (Kaihara, S.)

107

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

International Nuclear Information System (INIS)

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

108

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

International Nuclear Information System (INIS)

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

109

Influence of gamma-ray irradiation on stress corrosion cracking of austenitic stainless steels for high-level waste packages  

International Nuclear Information System (INIS)

The high level radioactive wastes produced from spent nuclear fuel must be kept in sound state for the period as long as 1000 years. At present as the canisters, austenitic stainless steel is considered as the proposed material, but its corrosion resistance under the irradiation of the gamma ray emitted from high level radioactive wastes has not been clarified sufficiently so far. Therefore, as a part of the safety research on high level radioactive wastes, the examination of the stress corrosion cracking of austenitic stainless steel under the irradiation of gamma ray was carried out. As the result, it was found that the sensitivity to stress corrosion cracking increased by gamma ray irradiation, besides, by increasing the irradiation dose rate. The test materials were SUS 304, SUS 304L and SUS 304 ELC, and double U-bend test pieces were used. The irradiation of gamma ray, the evaluation of SCC sensitivity, the electrochemical measurement and the SCC test at constant potential are explained. The experimental results are reported. The oxidizing substance formed by the radiolysis of water due to gamma ray irradiation seemed to increase the sensitivity. (Kako, I.)

110

Space as an Adverse Environment: Vacuum Surface and Gamma Ray Irradiation Effects on LED's and Photodiodes  

Science.gov (United States)

Vacuum surface and gamma-ray irradiation effects on photodiodes and LED's play a significant role in the optical and electronic properties of these diodes, particularly in a space environment, which involves both ionizing radiation as well as vacuum conditions. Exposure of GaAs light emitting diodes (LED's) to vacuum gives rise to desorption of surface-adsorbed gases and subsequent free charge diffusion and redistribution that significantly alter diode properties. Changes in photodiode properties due to vacuum operation and y-radiation have also been observed. These changes are given, and a model explaining the changes is presented.

Hava, S.; Kopeika, N. S.

1987-02-01

111

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

International Nuclear Information System (INIS)

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

112

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

Science.gov (United States)

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

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

1974-01-01

113

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

114

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

115

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

CERN Document Server

LHC, working at the expected nominal luminosity, will induce an extremely high irradiation in the CMS experiment. The CMS alignment system uses optical elements to build the laser beams paths. Optical properties of basic components such as glasses and glues may result affected and their transmission power may degrade significantly. We have proceeded to a first test of various glasses and glues and identified some of them that can stand up to 150 kGy of gamma-rays plus 5 multiplied by 10**1**4 neutrons/cm**2.

Beigveder, J M; Barcala, JM; Calvo, E; Fernández, M G; Ferrando, A; Figueroa, C F; Fuentes, J; Genova, I; Josa-Mutuberria, I; Molinero, A; Oller, J C; Pérez, G; Rodrigo, T; Ruiz, J A

2002-01-01

116

Free ion yield observed in liquid isooctane irradiated by gamma rays. Comparison with the Onsager theory  

CERN Document Server

We have analyzed data on the free ion yield observed in liquid isooctane irradiated by Co60 gamma rays within the framework of the Onsager theory about initial recombination. Several distribution functions describing the electron thermalization distance have been used and compared with the experimental results: a delta function, a Gaussian type function and an exponential function. A linear dependence between free ion yield and external electric field has been found at low electric field values (E<1.2 MV/m) in excellent agreement with the Onsager theory. At higher electric field values we obtain a solution in power series of the external field using the Onsager theory.

Pardo, J; Iglesias, A; Lobato, R; Mosquera, J; Pazos, A; Peña, J; Pombar, M; Rodríguez, A; Sendon, J

2003-01-01

117

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

International Nuclear Information System (INIS)

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

118

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

International Nuclear Information System (INIS)

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

119

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

International Nuclear Information System (INIS)

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

120

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-01

121

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

International Nuclear Information System (INIS)

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

122

Electron trapping in rad-hard RCA IC's irradiated with electrons and gamma rays  

Science.gov (United States)

Enhanced electron trapping has been observed in n-channels of rad-hard CMOS devices due to electron and gamma-ray irradiation. Room-temperature annealing results in a positive shift in the threshold potential far beyond its initial value. The slope of the annealing curve immediately after irradiation was found to depend strongly on the gate bias applied during irradiation. Some dependence was also observed on the electron dose rate. No clear dependence on energy and shielding over a delidded device was observed. The threshold shift is probably due to electron trapping at the radiation-induced interface states and tunneling of electrons through the oxide-silicon energy barrier to fill the radiation-induced electron traps. A mathematical analysis, based on two parallel annealing kinetics, hole annealing and electron trapping, is applied to the data for various electron dose rates.

Danchenko, V.; Brashears, S. S.; Fang, P. H.

1984-01-01

123

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

International Nuclear Information System (INIS)

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

124

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)

125

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

International Nuclear Information System (INIS)

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

126

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

Energy Technology Data Exchange (ETDEWEB)

The 70SnF{sub 2}{center_dot}30P{sub 2}O{sub 5} glasses containing 25-500 ppm of fluorescein exhibit change in color from light yellow to reddish orange (absorption maximum, {lambda}=500 nm) when heated at 240degC for 120-180 min. The fluorophosphate glasses also change the color from light yellow to reddish brown ({lambda}=480 nm) when irradiated with {sup 60}Co {gamma}-rays of 5x10{sup 4} Gy. The P-F stretching mode observed in the Fourier transformed infrared (FT-IR) spectra showed an increase in peak intensity along with the coloration, suggesting a cleavage of the weak chemical bond between fluoride ions (F{sup -}) and fluorescein molecules. The coloration is ascribed to change of the molecular structure of fluorescein from non-crystalline to crystalline type. ESR spectra of {gamma}-ray irradiated 70SnF{sub 2}{center_dot}30P{sub 2}O{sub 5} glasses showed a poorly resolved doublet, which was ascribed to a hole-trapped PO{sub 3}F{sup -} center produced by electron scattering: PO{sub 3}F{sup 2-} {yields} PO{sub 3}F{sup -} + e{sup -}. (author).

Nishida, Tetsuaki; Sasaki, Shigeo; Toma, Tetsuya; Maeda, Yonezo [Kyushu Univ., Fukuoka (Japan). Faculty of Science

1995-04-01

127

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%

128

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

129

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

130

Radiation-induced reduction of diuron by gamma-ray irradiation  

International Nuclear Information System (INIS)

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

131

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

International Nuclear Information System (INIS)

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

132

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

International Nuclear Information System (INIS)

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

133

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

International Nuclear Information System (INIS)

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

134

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

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

Pejovi? Mili? M.

2013-01-01

135

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

International Nuclear Information System (INIS)

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

136

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

International Nuclear Information System (INIS)

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

137

TL and PTTL in natural fluorite previously irradiated with gamma rays and heavy ions  

International Nuclear Information System (INIS)

The effect of annealing temperature on the phototransfer thermoluminescence (PTTL) signal was studied to determine the appropriate annealing temperature for treating the natural powder before irradiation. The temperatures used to anneal virgin natural fluorite samples (only natural dose without giving the samples any artificial doses) were 150, 250, 350, 450, 550, 650 and 750oC for a duration of 1 h in each case. The results show that the PTTL response did not change for anneal temperatures up to 450oC, but at higher temperatures the signal decreased rapidly. The height of the 90oC peak decreased by two orders of magnitude as the anneal temperature increased from 450 to 750oC, whilst the height of the 180oC peak decreased by three orders of magnitude between the same two annealing temperatures. In order to investigate the effect of previous gamma rays and heavy ion irradiation on thermoluminescence (TL) and PTTL signals, powdered samples of natural fluorite from Cornwall, England, were annealed at 500oC and then irradiated (at GSI, Darmstadt, Germany) with 161Dy ions of energy 13 Mev/n; the range of fluences used was from 104to 1012 ion cm-2. Identical samples were given gamma doses in the range 1 Gy to 2.6 x 104 Gy in order to compare the effects of gamma rays and heavy ions. The sensitivities of TL and PTTL were studied by giving the samples a gamL were studied by giving the samples a gamma test dose of 1 Gy after annealing the samples at 500oC for 30 min in order to eliminate the TL resulting from previous gamma or heavy ion irradiation. (Author)

138

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

International Nuclear Information System (INIS)

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

139

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

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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

140

Effect of thyroid gland function following /sup 60/Co-. gamma. ray irradiation on rabbit pituitary gland  

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Cobalt 60 gamma-ray irradiation using a single exposure at 10 Gy or 20 Gy was applied to the hypophysis in rabbits in order to study the relationship between thyroid-stimulating hormone (TSH) and thyroid hormone (T/sub 4/) after irradiation, and the histopathologic features were observed together with determination of the blood T/sub 4/ levels. The histopathologic features were observed with special reference to changes in the ..beta.. cells of the anterior lobe of the hypophysis involved in TSH secretion using mainly hematoxylin and eosin staining. Blood T/sub 4/ level was determined by radioimmunoassay, and the histopathologic features and hormone levels were compared between the 10 Gy- and 20 Gy-irradiation groups. The following results were obtained: 1) The T/sub 4/ level rapidly decreased the day following irradiation in both groups, continuing for 3 days and 7 days, respectively. subsequently, the level rapidly returned to the pre-irradiation level about 14 days after irradiation in the 10 Gy group, while the level in the 20 Gy group continued to decrease at a rate significantly different from that in the 10 Gy group even after 14 days following irradiation. However, the level was restored to the pre-irradiation level in both groups 28 days after irradiation. 2) Histopathologic examination of the anterior lobe of the hypophysis revealed a decrease in the number of ..beta.. cells until about 14 days after irradiation in both groups, and thereafter there were only a few changes. However, pyknosis and vacuolar degeneration of other cells and dilatation of sinusoidal capillaries were present for a relatively long period, which were not relieved even 28 days after irradiation, particularly in the 20 Gy group. 3) There was a relatively close relationship between changes in the ..beta.. cells of the anterior lobe of the hypophysis and changes in blood T/sub 4/ level, but histopathologic changes in the hypophysis seemed to remain for a relatively long period.

Muramatsu, Shigenori

1987-10-01

141

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

International Nuclear Information System (INIS)

The investigation of gamma tays 60Co irradiation effect on resistance of bacteri P.aeruginosa has been done.The objective of the research was to know the D10 value of bacteria P.aeruginosa. By using of distilled water,talc and peanut powder as carrier in dry,wet,O2 and N2 condition the bacteria of P.aeruginosa were irradiated on gamma rays of 60Co with dose of O to 2.5 kGy,and with dose rate of 5 and 10 kGy/h.After irradiation the bacteria of P. aeruginosa were cultured in media of the Tryptone Soya Agar and incubatedat temperature of 32±2oC for 3 days. The survival colonies were calculated,and the data were used to make the curve and to determine the D10 value. The results of the experiments showed that D10 value of irradiated bacteria of P.aeruginosain the disitilled water,talc and peanut powder as carrier were not high significant.Nevertheless the D10 value of the irradiated at dose rate 10kGy/h show more higher tendency than at dose rate 5kGy/h. The D10 value of irradiated bacteria in the N2 condition was higher,if compared with in the O2 condition

142

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

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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

143

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

144

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

International Nuclear Information System (INIS)

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

145

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

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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

146

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)

147

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

International Nuclear Information System (INIS)

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

148

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

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The present study was aimed to obtain dose-response relationships for the excess mortality from all causes and carcinogenesis after irradiation at juvenile period with gamma rays from {sup 137}Cs. B6C3F{sub 1} female mice were irradiated at 0 or 7 days of age with doses ranging from 0.19 to 5.7 Gy, and all the mice were allowed to live out their entire life span under a specific pathogenfree condition. The excess mortality in mice irradiated with 0.19 Gy at 0 day of age was estimated to be 8.8%. Mice of 7 days of age seemed to be more sensitive to induction of lethal diseases, as the excess mortality reached 22.3% after irradiation with 0.19 Gy. Dose-response relationship for the excess mortality was well described by an equation EM(D)=1- exp(-aD), where EM(D) represents excess mortality in a group irradiated with dose D. Incidences of liver tumors, pituitary tumors, ovarian tumors and lung tumors were significantly higher than control group in mice irradiated with doses lower than 1 Gy at 0 day of age. Shape of dose-response curves for these tumors was convex upward. Dose-response relationships were analyzed using a model which includes tumorigenic activity of radiation, sterilization of potentially tumorigenic cells and competing risks. Analysis of the experimental data showed that tumorigenic activity was proportional to dose for induction of these tumors. Relative risks at 1 Gy were estimated to be 2.52, 2.79, 16.5 and 3.17 for induction of liver tumors, pituitary tumors, ovarian tumors and lung tumors, respectively. This result implies that mice of the neonatal period are highly susceptible to induction of these tumors. On the other hand, shape of dose-response curve for incidence of bone tumors was concave upward. Dose-response relationship for induction of bone tumors was fitted by a model that tumorigenic activity of gamma rays is proportional to square of dose. (author)

Sasaki, Shunsaku [National Inst. of Radiological Sciences, Chiba (Japan)

1999-06-01

149

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

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

MUH RAHMAD SUHARTANTO

2010-01-01

150

DIVERSITY OF STRAIN EVALUATION THREE RICE (ORYZA SATIVA FENOTIPE GAMMA RAY IRRADIATED THE RESULTS OF GROWTH AND PRODUCTION  

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Full Text Available Induction of mutations by gamma-ray irradiation is known as one of the techniques to develop new rice genotypes. The purpose of this study will provide a gamma ray irradiation on the growth and diversity of production lines AC6DH1-103, KA0048 and KA0052. The second objective is to obtain the optimum dose to increase growth and production lines AC6DH1-103, KA0048 and KA0052. The study of mutations induced by gamma-ray irradiation on the seeds, using completely randomized design with two factors, the first factor is genotype, namely: AC6 DH1 103, KA0048 and KA0052. The second factor is the dose of gamma-ray irradiation, namely: 0, 100, 150 and 200 Gy. Place rice improvement research through mutation induction performed at the Center for Application of Isotopes and Radiation Technology, National Nuclear Energy Agency (Batan, Jakarta Friday Market using Gamma Chamber-type 4000A and planting a seed irradiation and mutant screening conducted in the green house of the Faculty of Agriculture, Islamic University of Kadiri Kediri. Evaluation of agronomic characters of M0 generation potential mutants showed that the variation of the strain and the growing power of the radiation dose. Largest growing power of each strain ie, strain DH1 AC6 103 100% dose of 200 Gy, 84% KA0048 and KA0052 dose of 100 Gy 74% dose of 150 Gy. AC6 DH1 strain 103 (M0 is more responsive to gamma-ray irradiation proved significant interaction was found on the variable contains the number of seeds, number of seeds per hill and empty weight of 100 seeds compared to the control.

Sumarji

2015-02-01

151

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

International Nuclear Information System (INIS)

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

152

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

International Nuclear Information System (INIS)

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

153

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-02-15

154

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

Scientific Electronic Library Online (English)

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

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

155

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

International Nuclear Information System (INIS)

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

156

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

International Nuclear Information System (INIS)

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

157

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

International Nuclear Information System (INIS)

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

158

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

159

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

160

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

International Nuclear Information System (INIS)

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

161

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

International Nuclear Information System (INIS)

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)

162

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 anrcentage of S cells in the tumor tissue and analysis of cell kinetics after irradiation and chemotherapy against cancer. (author)

163

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

International Nuclear Information System (INIS)

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

164

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-01

165

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-12-15

166

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

167

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

168

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.)

169

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

International Nuclear Information System (INIS)

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

170

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-03-15

171

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

International Nuclear Information System (INIS)

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

172

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

International Nuclear Information System (INIS)

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

173

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

174

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.

175

Teratogenic effects of 60Co gamma rays irradiation on rat embryos  

International Nuclear Information System (INIS)

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

176

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

177

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-04-01

178

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

International Nuclear Information System (INIS)

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

179

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

Science.gov (United States)

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. PMID:23546297

Vieira, Renata de Freitas Fischer; Nardi, Daniela Teves; Nascimento, Nanci; Rosa, José César; Nakaie, Clovis Ryuichi

2013-01-01

180

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

International Nuclear Information System (INIS)

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

181

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

International Nuclear Information System (INIS)

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

182

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

183

[Organoleptic changes in beef and pork fats following gamma-ray irradiation].  

Science.gov (United States)

Studied were bovine and swine fats that had been treated with gamma-rays at the rates of 0.10 to 2.00 Mrad, in the presence of oxygen and in an atmosphere containing no oxygen as well as under storage conditions at 2 to 4degreesC, and -- 18 and up to --20degreesC, for 45 and 90 days, respectively. When doses of 0.25 Mrad were used no changes in the organoleptic properties were observed. Fats that were treated at the rate of more than 0.25 Mrad in the presence of oxygen assumed 'side' smell and taste. If irradiation was carried out in the absence of oxygen no such deviations from the normal taste and odor were noted--at rates of up to 0.70 Mrad for the swine fats, and at rates of more than 0.50 Mrad for the bovine fats. Destruction of the yellow pigment in the bovine fats was observed at treatment with doses higher than 0.70 Mrad. The changes in the organoleptic properties corresponded to the changes taking place with the peroxides, the water soluble fatty acids, and the epihydrinaldehyde. Changes in the organoleptic properties (odor and taste) in the bovine fats took place at lower doses of iradiation than in the swine fats. PMID:951932

Iordanov, I

1976-01-01

184

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

Directory of Open Access Journals (Sweden)

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

S. Human

2011-12-01

185

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

International Nuclear Information System (INIS)

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

186

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

International Nuclear Information System (INIS)

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

187

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)

188

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

Directory of Open Access Journals (Sweden)

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

Carlos Augusto F. Peregrino

2005-09-01

189

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

International Nuclear Information System (INIS)

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

190

Studies on the radicidation of natural food colorants. Effects of irradiation with {gamma}-ray and electron beam on functional properties of beet red colorant  

Energy Technology Data Exchange (ETDEWEB)

For the practical use of radicidation, we studied on the effects of {gamma}-ray and electron beam on functional properties of beet red colorant, natural colors with low heat stability and high possibility of microbe contamination. Neither {gamma}-ray or electron beam had any significant influence on color contents and color tone of red beet products at less than 10 kGy of irradiation for the practical use. Influence of moisture content at level of less than 20% in powdered product was not observed. The results suggest that both {gamma}-ray and electron beam irradiation is significantly effective in decontamination of powdered beet red products. (author)

Higashimura, Yutaka; Tada, Mikiro [Okayama Univ. (Japan). Graduate School of Natural Science and Technology; Todoriki, Setsuko [National Food Research Inst., Tsukuba, Ibaraki (Japan)

2002-05-01

191

Impact of gamma-ray-pre-irradiation on the efficiency of corrosion inhibition of some novel polymeric surfactants  

International Nuclear Information System (INIS)

The effect of gamma-ray-pre-irradiation on the efficiency of two types of polymeric surfactants, (I and II) as corrosion inhibitors for 304 stainless steel in 2 M hydrochloric acid solution was examined. The inhibition efficiency of the undertaken additives was evaluated using both chemical and electrochemical techniques. The chemical structure of the two polymeric surfactants is illustrated as follows: where MA=maleic anhydride; BP=block polymer of polyoxy ethylene-polyoxy propylene (M.Wt=5000 gmol-1).The obtained corrosion data, indicated that the corrosion inhibition efficiency of the inhibitor (II) was obviously not affected by gamma-ray-irradiation, meanwhile the efficiency of the inhibitor (I) demonstrated a remarkable decrease. Scanning electron microscope (SEM) was used to examine the surface morphology of stainless steel samples after immersion in 2 M HCl solution in absence and presence of the inhibitors at concentration of 400 ppm before and after exposure to gamma-ray-radiation up to a total does of 100 kGy

192

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

International Nuclear Information System (INIS)

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

193

Spectral tuning of shallow-junction surface-emitting light-emitting diodes (LEDs) through gamma-ray irradiation  

International Nuclear Information System (INIS)

The present investigation is concerned with the effects produced in GaAs LEDs through gamma-ray irradiation, taking into account very shallow junction LEDs, in which the junction is only on the order of 0.1 micron beneath the semiconductor surface. The obtained results show that the exposure of surface-emitting P-type devices to gamma rays can bring about many desirable improvements in LED parameters. The observed changes are related to increased wavelength (desirable in GaAs devices to decrease material dispersion), decreased storage time (implies higher modulation rates), and the narrowing of linewidth for moderate dosages. All these improvements are obtained without any noticeable disadvantages. On the other hand, in connection with spectral changes, it might not be advisable to employ shallow junction heavily doped surface emitters in nuclear radiation environments

194

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

International Nuclear Information System (INIS)

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

195

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

196

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

International Nuclear Information System (INIS)

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

197

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

International Nuclear Information System (INIS)

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

198

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 anexes. 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

199

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

OpenAIRE

Gamma-ray irradiation and post-irradiation response at room and elevated temperature have been studied for radiation sensitive pMOS transistors with gate oxide thickness of 100 and 400 nm, respectively. Their response was followed based on the changes in the threshold voltage shift which was estimated on the basis of transfer characteristics in saturation. The presence of radiation-induced fixed oxide traps and switching traps - which lead to a change in the threshold voltage - was esti...

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

2011-01-01

200

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

International Nuclear Information System (INIS)

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

201

Recovery of damage in rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays  

Science.gov (United States)

This paper reports on the recovery properties of rad-hard MOS devices during and after irradiation by electrons, protons, alphas, and gamma rays. The results indicated that complex recovery properties controlled the damage sensitivities of the tested parts. The results also indicated that damage sensitivities depended on dose rate, total dose, supply bias, gate bias, transistor type, radiation source, and particle energy. The complex nature of these dependencies make interpretation of LSI device performance in space (exposure to entire electron and proton spectra) difficult, if not impossible, without respective ground tests and analyses. Complete recovery of n-channel shifts was observed, in some cases within hours after irradiation, with equilibrium values of threshold voltages greater than their pre-irradiation values. This effect depended on total dose, radiation source, and gate bias during exposure. In contrast, the p-channel shifts recovered only 20 percent within 30 days after irradiation.

Brucker, G. J.; Van Gunten, O.; Stassinopoulos, E. G.; Shapiro, P.; August, L. S.; Jordan, T. M.

1983-01-01

202

Gamma-ray and ions irradiation effects on the optical property of CR-39 detector and their latent track size  

International Nuclear Information System (INIS)

Spectral study has been made for the gamma-ray and ions (3.4 MeV; H+, 6.8 MeV; He2+, 8.5 MeV; C4+, 7.0 MeV; O4+) irradiated CR-39 track detectors using UV-visible, Near-IR, FT-IR and Raman spectroscopy. The optical density of gamma irradiated samples in the UV region increased with the dose. While, those of ions irradiated ones had peaks at certain fluences where the track overlapping became significant. Based on the fluence dependence and the simple track over-lapping model, the typical track sizes and their LET dependence were obtained. The spectra of IR and Raman indicated the decrease of -CH2- group and the production of OH- group after irradiations. (author)

203

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

Directory of Open Access Journals (Sweden)

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

Pejovi? Mom?ilo M.

2011-01-01

204

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

CERN Document Server

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

Yunusov, M S; Dzhalelov, M A

2001-01-01

205

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

International Nuclear Information System (INIS)

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

206

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

International Nuclear Information System (INIS)

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

207

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

International Nuclear Information System (INIS)

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

208

Induced mitotic gynogenesis in common carp (Cyprinus carpio L.), optimizing irradiation dose of X- and gamma-ray  

International Nuclear Information System (INIS)

Mitotic gynogenesis was induced in common carp, Cyprinus carpio L., in hatchery and laboratory conditions, using 60Co gamma-ray and X-ray for inactivation of sperm DNA and a subsequent heat shock for inducing endomitosis. The parameter examined was the dose of irradiation in the range of 70-140 Krad. Carp spermatozoa irradiated by 70-100 Krad doses showed higher motility and fertilization ability than the ones irradiated by 110-140 Krad. Sperm treated with doses of 70-90 Krad showed the same fertility rate, but lower survival rate at embryo stage compared with 100 Krad. The shock temperature and duration applied in these experiments for restoration of diploidy level were 40 degrees C plus/minus 0.1 and 2 min., respectively. The highest frequency of mitotic gynogenetic larvae was achieved by 100 Krad 60Co gamma ray at 34 min. after fertilization, - up to 12.2 percent (at 23 degrees C incubating temperature)

209

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

Scientific Electronic Library Online (English)

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

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

2005-09-01

210

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

Science.gov (United States)

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

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

2014-05-01

211

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

International Nuclear Information System (INIS)

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

212

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-05-15

213

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

International Nuclear Information System (INIS)

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

214

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

International Nuclear Information System (INIS)

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

215

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

2009-08-01

216

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

International Nuclear Information System (INIS)

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

217

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

Science.gov (United States)

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

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

2014-12-01

218

Irradiation effects in KAPTON polyimide film from 14-MeV neutrons and cobalt-60 gamma rays  

International Nuclear Information System (INIS)

Polyimide films are insulating plastic materials that are useful over wide temperature range and the most radiation resistant of the polymers. In this paper, mechanical property changes of the polyimide film, KAPTON, caused separately by 14-MeV neutrons and by cobalt-60 gamma rays are examined in detail. Miniature tension specimens of 3-mil-thick film were irradiated at Rotating Target Neutron Source-II and at the Cobalt-60 Pool of Lawrence Livermore National Laboratory at room temperature to a maximum neutron fluence of 1.6 X 10/sup 22/ n/m/sup 2/ and a maximum gamma dose of 8.6 X 10/sup 7/Gy, respectively. Neutron fleunces greater than 1 X 10/sup 21/ n/m/sup 2/ and gamme dose greater than 2.2 X 10/sup 7/Gy caused a reduction in total elongation of the film. At the authors highest tested neutron fluence of 1.6 X 10/sup 22/ n/m/sup 2/, the elongation dropped to less than one-fifth and the fracture stress dropped to one-third of the unirradiated value. It was found that the 14-MeV neutrons were about eight times for effective than cobolt-60 gamma rays in producing mechanical property changes when compared on the basis of absorbed dose. Color changes induced by irradiation were also examined

219

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

220

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

International Nuclear Information System (INIS)

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

221

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-10-15

222

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

International Nuclear Information System (INIS)

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

223

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 situationcameras 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

224

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-05-15

225

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

226

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-10-11

227

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-09-01

228

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

International Nuclear Information System (INIS)

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

229

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

230

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

International Nuclear Information System (INIS)

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

231

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

International Nuclear Information System (INIS)

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

232

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

International Nuclear Information System (INIS)

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

233

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

234

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

235

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)

236

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

237

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

International Nuclear Information System (INIS)

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

238

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

International Nuclear Information System (INIS)

In literature there are many results which have shown that low dose radiation can stimulate many physiological processes of living organism. In our earlier paper it was shown that low dose of gamma radiation has a stimulative effect upon metabolic process in chickens hatched from eggs irradiated before incubation. This was proved by increase of body weight gain and body weight, as well as by increase of two enzymes activities in blood plasma (aspartate aminotransferase and alanine aminotransferase) which play an important role in protein metabolism. Therefore, an attempt was made to determine the effect of eggs irradiation by low dose gamma rays upon concentration of total proteins and protein fractions in the blood plasma of chickens hatched from irradiated eggs. The eggs of heavy breed chickens were irradiated with a dose of 0.15 Gy gamma radiation (60Co) before incubation. Along with the chickens which were hatched from irradiated eggs, there was a control group of chickens hatched from nonirradiated eggs. All other conditions were the same for both groups of chickens. Blood samples were taken from the right jugular vein on the 1st and 3rd day, or from the wing vein on days 5 and 7 after hatching. The total proteins concentration in the blood plasma was determined by the biuret method using Boehringer Mannheim GmbH optimized kits. The protein fractions (albumin, ?1-globulin, ?2-globulin, ?- and ?-globulins) were estimated electrophoretically on Cellogel strips. The total proteins concentration was significantly decreased in blood plasma of chickens hatched from irradiated eggs on days 3 (P th day (P 2-globulin was decreased on days 1 (P th day of life. Obtained results indicate that low dose of gamma radiation has mostly inhibitory effect upon concentration of total proteins and protein fractions in the blood plasma of chickens hatched from irradiated eggs before incubation. (author)

239

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

International Nuclear Information System (INIS)

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

240

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

International Nuclear Information System (INIS)

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

241

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)

242

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

243

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)

244

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

International Nuclear Information System (INIS)

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

245

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

246

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

247

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

International Nuclear Information System (INIS)

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

248

Gamma ray irradiation induced optical band gap variations in chalcogenide glasses  

International Nuclear Information System (INIS)

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

249

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)

250

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

251

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

International Nuclear Information System (INIS)

The gamma-ray activity from short-lived fission products has been measured in fresh and burnt UO2 fuel samples after irradiation in a zero-power reactor. For the first time, short-lived gamma-ray activity from fresh and burnt fuel has been compared and fresh-to-burnt fuel fission rate ratios have been derived. For the measurements, well characterized fresh and burnt fuel samples, with burn-ups up to 46 GWd/t, were irradiated in the zero-power research reactor PROTEUS. Fission rate ratios were derived based on the counting of high-energy gamma-rays above 2200 keV, in order to discriminate against the high intrinsic activity of the burnt fuel. This paper presents the measured fresh-to-burnt fuel fission rate ratios based on the 142La (2542 keV), 89Rb (2570 keV), 138Cs (2640 keV) and 95Y (3576 keV) high-energy gamma-ray lines. Comparisons are made with the results of Monte Carlo modeling of the experimental configuration, carried out using the MCNPX code. The measured fission rate ratios have 1? uncertainties of 1.7–3.4%. The comparisons with calculated predictions show an agreement within 1–3?, although there appears to be a slight bias (?3%).

252

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-01-11

253

Effect of gamma ray irradiation on optical properties of Nd doped phosphate glass  

International Nuclear Information System (INIS)

The effect of gamma irradiation in the dose range of 5-500 kGy on the optical absorption and luminescence spectra of Nd doped phosphate glass is reported. The spectral absorption of this glass before and after gamma irradiation was measured in the spectral range 300-900 nm at room temperature using spectrophotometer and synchrotron beamline. Drastic increase in absorption was noted below 600 nm after gamma irradiation, which was dependent on the dose of irradiation. Additional absorption (AA) spectra of irradiated sample shows generation of two absorption bands below 600 nm, which finally became one very broad band peak with increased intensity at irradiation dose of 500 kGy. AA spectra also show the presence of negative peaks at the location of absorption peaks of Nd3+. Photoluminescence of Nd doped phosphate glass shows two strong bands which decreases to a very low intensity with a red shift after gamma irradiation. These results indicate that irradiation produces different kinds of defects in the glass material along with conversion of valence state of Nd3+ to Nd2+. This change was found irreversible at room temperature.

254

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

Science.gov (United States)

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

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

2014-05-01

255

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

International Nuclear Information System (INIS)

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

256

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

International Nuclear Information System (INIS)

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

257

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

International Nuclear Information System (INIS)

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

258

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

International Nuclear Information System (INIS)

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

259

Apparatus for gamma ray radiography  

International Nuclear Information System (INIS)

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

260

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

International Nuclear Information System (INIS)

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

261

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

Directory of Open Access Journals (Sweden)

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

Susilawati

2009-01-01

262

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.

Anbo Wang

2007-05-01

263

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

International Nuclear Information System (INIS)

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. (author)

264

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

International Nuclear Information System (INIS)

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

265

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

Science.gov (United States)

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

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

2014-09-01

266

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

International Nuclear Information System (INIS)

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

267

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

International Nuclear Information System (INIS)

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

268

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

International Nuclear Information System (INIS)

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

269

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

International Nuclear Information System (INIS)

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

270

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

271

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

International Nuclear Information System (INIS)

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

272

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

International Nuclear Information System (INIS)

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

273

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

International Nuclear Information System (INIS)

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

274

Effect of {gamma}-ray irradiation on breakdown voltage, ideality factor, dark current and series resistance of GaAs p-i-n diode  

Energy Technology Data Exchange (ETDEWEB)

Effect of {sup 60}Co {gamma}-ray radiation with 1 Multiplication-Sign 10{sup 16} {gamma}/cm{sup 2} fluence on the ideality factor, saturation current and series resistance for two separate junctions p-i and i-n of p-i-n diode are studied by using temperature dependent current-voltage measurements and {beta} model analysis. After {gamma}-ray irradiation, the resistance of p-i-n diode increases from 858 to 2789 {Omega}. This is due to the fact that unintentional impurities (mainly carbon) present in the i-region change their positions from Gallium to Arsenic sites and subsequently transform them to the acceptor like states. The dark and saturation current decrease following the {gamma}-ray irradiation because of the reduced electron mobility and the compensation of majority carriers by the acceptor like trap states. In addition, the ideality factor of p-i junction decreases from 1.5 to 1.2 while for the i-n junction it increases from 7.2 to 8 after irradiation at 300 K. The ideality factor for the second junction is enhanced due to the increased recombination probability of carriers at the trap centers in the intrinsic region. Positive temperature coefficient of the breakdown voltage confirms that the avalanche multiplication process is responsible for the junction breakdown. Further, the breakdown voltage increases after the irradiation because of the scattering of charge carriers from the radiation induced defects.

Pillai, Vinu R.V.; Khamari, Shailesh K. [Semiconductor Laser Section, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, M. P. (India); Dixit, V.K., E-mail: dixit@rrcat.gov.in [Semiconductor Laser Section, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, M. P. (India); Ganguli, T. [Indus Synchrotrons Utilisation Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, M. P. (India); Kher, S.; Oak, S.M. [Semiconductor Laser Section, Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, M. P. (India)

2012-09-01

275

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

International Nuclear Information System (INIS)

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

276

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)

277

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

International Nuclear Information System (INIS)

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

278

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

International Nuclear Information System (INIS)

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

279

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-01

280

Flashover characteristics of poloidal field coils under gamma-ray irradiation  

International Nuclear Information System (INIS)

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

281

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

Science.gov (United States)

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

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

2014-10-01

282

Growth evaluation of avocado selections irradiated with gamma rays Co 60  

International Nuclear Information System (INIS)

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

283

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

International Nuclear Information System (INIS)

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

284

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

International Nuclear Information System (INIS)

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

285

Irradiation and gamma-ray spectrometric parameters for 129I neutron activation analysis  

International Nuclear Information System (INIS)

This paper describes the influence of reactor neutron irradiation facilities on low-level 129I analysis methodology. Three reactors are compared - the HFIR at ORNL, the N-Reactor at Hanford, and a 1-MW research reactor at Washington State University, Pullman, WA. Parameters compared include sensitivity for 129I and natural iodine and interference effects due to high levels of 127I in irradiated samples. Selection of detector systems for off-site use at HFIR is discussed. A comparison of neutron activation analysis with other sensitive detection methods for measurement of 129I is given

286

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

International Nuclear Information System (INIS)

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

287

Effect of Milling Process on the Electron Spin Resonance Center Formation in Pyrex Glass by Gamma-Ray Irradiation  

Science.gov (United States)

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.

Hirai, Makoto; Ikeya, Motoji

2004-08-01

288

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

International Nuclear Information System (INIS)

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

289

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

International Nuclear Information System (INIS)

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

290

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

291

Changes in the ultrastructure of alveolar macrophages from golgen hamsters irradiated with gamma rays  

International Nuclear Information System (INIS)

The study involved alveolar macrophages (AM) from acute whole-body gamma irradiated golden hamsters of both sexes (0.5 Gy and 6 Gy, 92.5 rad/min). AM were obtained by the method of Myrvik et al. on days 1, 3, 7, 15 and 30 after irradiation. As the case with guinea pigs, two types of AM were observed - small and large, which differed slightly in morphology and were considered as young and mature forms. The following marked changes in the AM ultrastructures were established: intense vacualization of endoplasmatic reticulum, with limited expansion of the perinuclear space, lysis of cytoplasmic matrix, increase in the number of the primary and secondary lysosomes, injures in mitochondrial crests, mitochondria matrix of lower density, formation of enormous vacuoles in cytoplasm. The injuries were more expressed in the higher dose irradiated animals. This was the reason for the perishing (total lysis) of a large percentage of the mature AM. AM of a more normal structure appeared only at the end of the experimental period (on day 30 after treatment). Particularly strong changes in the ultrastructure of the nuclei were observed in the small AM: homogenization (diffuse distribution) of the chromatin and considerable thickening of the internal lamella of the nuclear membrane. These facts offered a convincing evidence that the total gamma irradiation of hamsters affected most strongly the genetic apparatus of the AM

292

Effect of gamma-ray irradiation on enzymatic hydrolysis of wood cellulose (dissolving)  

International Nuclear Information System (INIS)

The susceptibility of cellulose to a cellulase is discussed in terms of its degree of polymerization (DP), crystallinity and accessibility to moisture which are varied by .gamma.-irradiation. Reducing sugar yield increases with decreases in crystallinity and degree of polymerization of cellulose associated with an increase in its accessibility to water

293

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

International Nuclear Information System (INIS)

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

294

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

295

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)

296

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

297

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

International Nuclear Information System (INIS)

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

298

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)

299

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

300

Flashover characteristics along coil insulation under intense gamma-ray irradiation  

International Nuclear Information System (INIS)

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

301

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

International Nuclear Information System (INIS)

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

302

Radiation-stimulated phenomena in quartz glass irradiated by gamma-rays and neutron  

International Nuclear Information System (INIS)

Full text: The talk deals with the influence of radiation (gamma and neutron) effects on optical and luminescence properties of quartz glass. By now, little is understood about the nature of both absorption band at 243nm and luminescence band at 294nm and 396 nm in quartz glass. So the present experiment was aimed at investigating samples of quartz glass, particularly pure and Ge-doped. In pure glass samples there were no absorption bands in ultraviolet and visible ranges of the optical absorption spectrum. On the contrary, in the case of Ge-alloyed samples there was an intensive absorption band having a peak at 243nm. After gamma-irradiation of pure samples (beginning from D?= 5*104 Rad) in the optical absorption band there appeared an absorption band with a peak at 215 nm. This band was due to the absorption of radiation-induced E1-centers. Under such conditions, in Ge-alloyed samples one more absorption band at 270-280 nm was observed, which was due to the absorption of Ge-center - E1. As the irradiation dose increased (up to 5*106 Rad), the intensity of the absorption band rose strongly and then achieved its saturation. It is difficult to make a conclusion on the kinetics of intensity of the absorption band with a peak at 243 nm because both short-wave (?19 n/cm2 fluency) the intensity of absorption band having the peak at 215 nm grows strongly in the spectra of optical absorption of Ge-alloyed and pure samples. In addition, a more effective growth of the absorption band with peaks at 243 nm and 270-280 nm is characteristic of samples irradiated with neutrons. The intensity of luminescence band with 400nm peak decreases after gamma-irradiation, which was observed in photolumintsence (PL) and Roentgen -luminescence (RL) spectra of pure Ge-samples. This tendency was also observed in neutron-irradiated samples at 1019 n/sm2 neutron fluency, and its intensity was much lower than that produced at gamma-irradiated samples. It should be noted that in pure samples irradiated with 107Rad ? -rays and 1019 n/sm2 neutron, 400nm luminescence band was not practically found in PL and RL spectra. After preliminary neutron irradiation by 1019 n/sm2 fluency, 460nm luminescence band due to recombination of h and e at oxygen vacancy was seen in this sample. As mentioned above, there is no common opinion about the model for absorption band in the 240-243 nm range and for luminescence at 294 and 396nm. However, from our results 243nm absorption band and 400nm luminescence band manifest themselves more effectively in Ge-alloyed samples. If both of the bands have Al-impurities, an absorption band in the vicinity of 550 nm, which is characteristic of defect of aluminum-hole center, should be registered. As follows from our results, no bands are observed in the visible part of the spectrum after gamma- and neutron irradiation. On the other hand, it is improbable to relate 243 nm absorption band and 400 nm luminescence to the defect of interstitial silicon because an increased intensity of the band should be expected after reactor irradiation. In practice, however, 400nm luminescence band was not observed in pure samples after gamma- and neutron irradiation. This circumstance favors 400nm luminescence band dependent on Ge-impurity in glass. One can conclude from our findings that the most probable model for 243 nm absorption band and for 400 nm luminescence is the center of oxygen vacancy with two neighboring atoms of silicon and germanium (?Si-Ge?). We also find that not an essential change in intensity of 243 nm absorption band is observed as the irradiation dose increases. Moreover, 400 nm luminescence band shows decrease in intensity. The observed radiation-induced effects seem to related to ?-radiation, which causes a change in local surroundings of initial defect state (?Si -Ge?) and lengthen thus bonds between Ge and Si (?Si --Ge?). In this case, depending on local surroundings there can be both vacancies, which are incapable to produce luminescence, and vacancies, which have ordinary bonds between atoms (?SiGe?) and

303

The linearity of the high temperature peaks in TLD100 for thermal neutrons and gamma rays irradiation  

International Nuclear Information System (INIS)

One of the problems that complicates the routine personal TL dosimetry with LiF:Mg,Ti, is the complexity of its glow curves, as many as 10 to 14 peaks have been identified at temperatures from 60 degree C to 400 degree C. Each peak may have different dosimetric characteristics, and may be differently dependent on a variety of factors, as the annealing procedure and type of radiation. It was observed already in the early years of TLD research, that when LiF is exposed to higher LET radiations, an enhanced sensitivity is obtained for the peaks in the 250 degree C region (6 and 7), compared to the usual dosimetry peaks (4 and 5, at about 200 degree C), and it was proposed to use this difference for mixed thermal neutron and gamma dosimetry. The development of sophisticated tools for glow curve analysis, especially the Computerized Glow Curve Deconvolution (CGCD), enabled accurate separation of the specific peaks and intensified the research on the various peaks properties. However, some major obstacles were detected, which diminished the attractiveness of using the high temperature peaks to discriminate between the neutron and gamma dose components. Peak 6 is very near to peak 5, which is the main dosimetry peak, and its separation from peak 5 is difficult, especially when measuring low doses. Peak 7 is more intense and well resolved, but its response was reported to be supra-linear, and therefore its use for neutron-gamma mixed dosimetry is questionable. In the present work we investigated the linearity of two regions of interest, one containing the main information from the peaks 6 and 7 and the other containing the main information from the main dosimetry peaks 4 and 5, after irradiation of the crystals with thermal neutrons and gamma rays. The irradiation was performed to relatively low doses, up to about 50mSv, which are the practical levels encountered in routine situations

304

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

International Nuclear Information System (INIS)

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

305

Development of gamma ray irradiation on induction of a long grain mutant and its application  

International Nuclear Information System (INIS)

A long grain mutant LGII B was isolated from II32B by irradiation, II32B is a maintainer line of three line hybrid rice. It was investigated that LGIIB had a lower percent of chalkness than its parent II32B in addition to the longer grain character, but all other agronomic and quality traits were similar to II32B. Genetic analysis indicated that the long grain trait was controlled by a dominant single gene. The LGIIB kept the high maintaining ability and high combination ability as II32B. The appearance quality of the hybrid rice will be improved if new sterile line would be bred with LGIIB. (authors)

306

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

International Nuclear Information System (INIS)

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

307

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)

308

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

International Nuclear Information System (INIS)

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

309

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.

310

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)

311

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

International Nuclear Information System (INIS)

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

312

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

International Nuclear Information System (INIS)

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

313

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

314

Gamma ray generator  

Science.gov (United States)

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

Firestone, Richard B; Reijonen, Jani

2014-05-27

315

Gamma-ray astronomy  

OpenAIRE

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

Pohl, Martin

2001-01-01

316

Gamma-ray irradiation resistance of silver doped GeS2–Ga2S3–AgI chalcohalide glasses  

International Nuclear Information System (INIS)

Highlights: • The ?-ray irradiation resistance of Ag doped chalcohalide glasses (GeS2–Ga2S3–AgI) has been investigated. • The introduction of silver ions plays a specific role in the modification of the gamma-ray irradiation resistance of glasses. • The sulfur exerts an important effect on the photo-sensitivity of chalcogenide glasses. - Abstract: In the present work, series of silver doped Ge–Ga–S–AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after ?-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the ?-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing ?-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses

317

Gamma-ray irradiation resistance of silver doped GeS{sub 2}–Ga{sub 2}S{sub 3}–AgI chalcohalide glasses  

Energy Technology Data Exchange (ETDEWEB)

Highlights: • The ?-ray irradiation resistance of Ag doped chalcohalide glasses (GeS{sub 2}–Ga{sub 2}S{sub 3}–AgI) has been investigated. • The introduction of silver ions plays a specific role in the modification of the gamma-ray irradiation resistance of glasses. • The sulfur exerts an important effect on the photo-sensitivity of chalcogenide glasses. - Abstract: In the present work, series of silver doped Ge–Ga–S–AgI chalcohalide glasses have been prepared and their optical transmission spectra are compared before and after ?-ray irradiation at different doses. The differential transmission spectra of the irradiated samples with and without Ag doping have been compared to characterize the ?-ray irradiation induced red-shift of electronic absorption and formation of color centers. Ag doping plays an important role in increasing ?-ray irradiation resistance of the chalcohalide glasses due to its specific effect on the valence band and the network structure of glasses.

Shen, W. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); ENEA-UTT-MATIRR, Via Anguillarese 301, 00123 Rome (Italy); Baccaro, S.; Cemmi, A. [ENEA-UTT-MATIRR, Via Anguillarese 301, 00123 Rome (Italy); Ren, J. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Z.; Zhou, Y. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); ENEA-UTT-MATIRR, Via Anguillarese 301, 00123 Rome (Italy); Yang, Y. [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen, G., E-mail: grchen@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2014-06-01

318

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

International Nuclear Information System (INIS)

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

319

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

DEFF Research Database (Denmark)

The mechanism of O2 formation has been studied in 60 Co ?-ray-irradiated Fe(II) + Cu(II) solutions at 0.01 N HClO4 and at 0.01, 0.08, and 0.80 N H2 SO4. In the H2 SO4 system, ${\\rm G}({\\rm O}_{2})$ rises to plateau levels near 0.02 as the ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratio increases. The plateau value diminishes slightly and is displaced toward higher ${\\rm CuSO}_{4}/{\\rm FeSO}_{4}$ ratios with increasing acidity. The perchlorate system differs from the sulfate only at high ${\\rm Cu}({\\rm ClO}_{4})/{\\rm Fe}({\\rm ClO}_{4})_{2}$ ratios where $G({\\rm O}_{2})$ rises to 0.10. The O2 yield of 0.02 is not derived from "spur" HO2, OH, H2 O2 or O2, although the increase in $G({\\rm O}_{2})$ above this level in the perchlorate system is attributed to H2 O2. "Spur" O atoms are postulated as the source of O2 with the yield, $G({\\rm O}_{2})$ = 0.02.

Bjergbakke, Erling; Hart, E.J.

1971-01-01

320

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

International Nuclear Information System (INIS)

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

321

Genetic effects of gamma ray and ion beam irradiation on plants  

International Nuclear Information System (INIS)

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

322

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

Energy Technology Data Exchange (ETDEWEB)

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

NONE

2011-07-01

323

Study of the current-voltage characteristics of a SiC radiation detector irradiated by Co-60 gamma-rays  

International Nuclear Information System (INIS)

The SiC semiconductor has recently emerged as an attractive material for an ionization radiation detection. A wide bandgap (3.03 eV) and high radiation damage resistance allow for the fabrication of detectors capable of operating at a high-temperature and in high radiation fields. The major aim of our study is to develop a robust detector which will be applied to harsh radiation environments. In this study, we fabricated the SiC radiation detectors and measured the current-voltage characteristics of SiC detectors irradiated by Co-60 gamma-ray source. The I-V curves showed a decrease of the leakage current with increasing dose rate of Co-60 gamma-ray in the 0-100 V bias voltage range

324

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

2013-01-01

325

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

326

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

International Nuclear Information System (INIS)

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

327

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

CERN Document Server

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

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

2012-01-01

328

Quantitative analysis of changes in colony forming ability and DNA double strand breaks in {gamma}-ray irradiated amoeboid cells of Physarum polycephalum  

Energy Technology Data Exchange (ETDEWEB)

Colony forming ability of {gamma}-ray irradiated amoeboid cells of acellular slime mold Physarum polycephalum, subsequently kept in a non-growing condition at 24degC, was larger than that just after irradiation. Though colony forming ability decreased in the cells kept at 0degC after irradiation, it increased to some extent in the cells subsequently treated in the non-growing condition at 24degC. Next, double strand breaks (dsbs) of cellular DNA were quantitatively analysed by single cell gel electrophoresis under neutral condition (pH 8.0). It was demonstrated that the amount of DNA dsbs in the cells kept at 24degC were smaller than both in those just after irradiation and in those kept at 0degC. These results suggest that so-called potentially lethal damages were recovered by growth inhibition in the cells kept at 24degC, and that the recovery accompanied repair of DNA dsbs. In addition, the fact that the amount of DNA dsbs in the cells kept at 0degC was not significantly different from that just after irradiation seems to mean that damages other than DNA dsbs were also recovered. Mechanisms underlying specifically high {gamma}-ray resistance of Physarum polycephalum were discussed. (author)

Hosoda, Eiko [Tokyo Metropolitan Isotope Research Center (Japan)

1997-03-01

329

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)

330

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

International Nuclear Information System (INIS)

A long-term radiation ecology research project called Field Irradiator-Gamma (FIG) was begun at the Whiteshell Nuclear Research Establishment in 1968. The experimental area is in southeastern Manitoba and is located on the western edge of the Precambrian shield. The object of the project is to study the ecological effects on a mixed boreal forest ecosystem of continuous exposure to a gradient of gamma radiation. The gradient ranges from 0 to 460 000 times the natural background radiation level. This paper describes the forest, the gamma irradiator and its radiation field, and the research programs

331

Critical parameters of superconducting crystals YBa2Cu3O7-x after combined irradiation with electrons and gamma-rays  

International Nuclear Information System (INIS)

The effect of structure defects produced by 1Mev electrons and 1,32 MeV gamma-rays on the critical parameters of superconducting crystals YBa2Cu3O7-x was studied, namely the superconducting transition critical temperature, the magnetisation critical current density and the flux pinning force at field 1-5 Tesla. The use of combined electron and gamma-irradiation has allowed to distinguish the contribution from oxygen defects into the pinning centers responsible for an increase in the magnetization critical current density from 4 to 7 · 108 A/m2 in a magnetic field of 3 Tesla. (author)

332

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

International Nuclear Information System (INIS)

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

333

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-04-24

334

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

Science.gov (United States)

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

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

2012-06-01

335

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

OpenAIRE

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

Badigannavar And Suvendu Mondal, Anand M.

2010-01-01

336

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)

337

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

International Nuclear Information System (INIS)

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

338

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

International Nuclear Information System (INIS)

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

339

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

International Nuclear Information System (INIS)

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

340

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-01-15

341

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

Directory of Open Access Journals (Sweden)

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

Xie Chuan-Xiao

2004-01-01

342

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

International Nuclear Information System (INIS)

The effects of radiation on the electrical-interface-state density (Dit) and series resistance (Rs) characteristics of BiFeO3 MOS capacitors were studied in this work. To study the response of MOS devices to gamma irradiation over a range of doses, MOS samples were irradiated using a Co-60 gamma-ray source from 0.5 to 16 grays at a dose rate of 0.0030 Gy/s. C–V and G/?–V measurements were recorded prior to and after irradiation at high (1 MHz) frequency. The effects of the radiation were determined from analysis of the C–V and G/?–V curves. A slightly decrease in the Rs values with increasing irradiation dose was observed. The total interface-state density was found to decrease because of the reordering and restructuring of radiation-induced defects in the MOS capacitors. The experimental results indicate that the electrical Rs and Dit characteristics of BiFeO3 MOS capacitors depend on the gamma-irradiation dose, and the calculated densities of the interface states are on the order of 1011 eV?1 cm?2. However, the calculated Dit values are not high enough to pin the Fermi level of the Si substrate and thereby corrupt device operation over the given dose range

343

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

International Nuclear Information System (INIS)

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

344

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-01-15

345

Gamma-ray sources  

International Nuclear Information System (INIS)

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

346

Application of the dual action model to mutation induction in Chinese hamster cells irradiated with gamma rays and fast neutrons  

International Nuclear Information System (INIS)

Experimental data on the dose-response for the induction of mutation to 8-azaguanine resistance are presented for asynchronous Chinese hamster cells exposed to gamma rays and several fast neutron spectra. The LET distributions of the neutron spectra are calculated, and the biological data are interpreted in terms of the 'dual action' formulae of Neary and of Keller and Rossi. The two formulae are nearly the same, and give a site diameter of approximately 0.7?m. The observed linear component of the gamma response is larger than would be expected, and this is attributed to a single-target component of response. A similar analysis is made of published data on mutation in Tradescantia occidentalis; the site diameter in this organism is 1.6?m and there is no evidence of a single target component of response. The ratio of cell killing to mutation is much higher in the Chinese hamster cells than in Tradescantia

347

Comparison of chromosome aberration frequencies in pre- and post-flight astronaut lymphocytes irradiated in vitro with gamma rays  

Science.gov (United States)

If radiosensitivity is altered in a microgravity environment, it will affect the accuracy of assessing astronauts' risk from exposure to space radiation. To investigate the effects of space flight on radiosensitivity, we exposed a crewmember's blood to gamma rays at doses ranging from 0 to 3 Gy and analyzed chromosome aberrations in mitotic lymphocytes. The blood samples were collected 10 days prior to an 8-day Shuttle mission, the day the flight returned, and 14 days after the flight. After exposure, lymphocytes were stimulated to grow in media containing phytohaemagglutinin (PHA) and mitotic cells were harvested for chromosome analysis using a fluorescence in situ hybridization (FISH) with whole chromosome specific probes. The dose response of total exchanges showed no changes in the radiosensitivity after the mission.

Wu, H.; George, K.; Willingham, V.; Cucinotta, F. A.

2001-01-01

348

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

International Nuclear Information System (INIS)

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

349

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

International Nuclear Information System (INIS)

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

350

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

International Nuclear Information System (INIS)

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

351

Sup(DL)50/30, growth, fecundity and fertility of the Biomphalaria glabrata snails irradiated with gamma rays from sup(60)Co  

International Nuclear Information System (INIS)

Biomphalaria glabrata, vectors of Schistosoma mansoni were irradiated with gamma rays from a Co sub(60) source and maintained in vitro for observation of its lethal rate during 30 days. The snails obtained for study were divided in two groups: the Isolated and Assembled; in the former, Biomphalaria glabrata were kept in reproductive isolation and the last group maintened then in colonies. Dl sub(50)/30 yielded 50,7 6 sub(y) for the Assembled group while the Isolated group shown 210,6 6 sub(y), with an increment of 279%. The rising of colonies has pointed up to an undiffetiation of owing to the growth of the snails, no difference was noted between all the groups observed. Fertility and fecundity, however, showed to be significantly greater in Isolated groups than in Assembled groups. (author)

352

Formation of 2,5-diamino-4-hydroxy-6-(2'-deoxyribosyl)-formamidopyrimidine from 2'-deoxyguanosine in aqueous solution irradiated with 60Co gamma-rays  

International Nuclear Information System (INIS)

2'-Deoxyguanosine in aqueous solution (5 x 10-4mol/dm3) was irradiated with 60Co gamma-rays under N2O. Products were separated by gel chromatography (cellulofine GC-15-m) and high performance liquid chromatography (Inertsil ODS-2). 2-Amino-4-hydroxy-5-formamido-6-(2'-deoxyribosyl) -aminopyrimidine was one of the main radiolytic products. The formation of 2,5-diamino-4-hydroxy-6-(2'-deoxyribosyl) -formamidopyrimidine was detected, this compound being verified by measuring it ultraviolet absorption spectrum and analyzing its trimethylsilylated derivative by gas chromato-mass spectrometry. Its yield in terms of 2-amino-4-hydroxy-5-formamido-6-(2'-deoxyribosyl) -aminopyrimidine was 1:3. (author)

353

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

International Nuclear Information System (INIS)

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

354

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)

355

Inelastic gamma ray logging system  

International Nuclear Information System (INIS)

An illustrative embodiment of the invention includes a system for providing inelastic neutron gamma ray measurements in a well borehole. A pulsed neutron source is used to irradiate earth formations in the vicinity of the borehole with 14 MeV neutrons. Gamma rays resulting from the inelastic scattering of these fast neutrons are detected by an encapsulated liquid scintillator used in conjunction with a photomultiplier. The resulting representative voltage pulses are input to pulse height analyzing apparatus having energy windows located to embrace the Compton distributions associated with calcium, silicon, oxygen and carbon. The number of counts occurring in each of these energy regions may then be interpreted in terms of quantities of interest with respect to the formations in the borehole vicinity

356

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-01-01

357

Gamma-ray bursts  

International Nuclear Information System (INIS)

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

358

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

International Nuclear Information System (INIS)

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

359

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

International Nuclear Information System (INIS)

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

360

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

Science.gov (United States)

Dendritic cells (DCs) are the most potent antigen-presenting cells and play a crucial role in the regulation of immune response and migration of DCs into secondary lymphoid tissues also play an important role in the initiation of innate and adaptive immunity. Radiation therapy is now a routine treatment for certain types of cancer and over 20 percent of cancer patients will require radiation therapy during the treatment of their disease. However, the influence of ionizing irradiation on the migratory ability of DCs is largely unknown. In this article, we report that ? ray irradiation can significantly inhibit LPS-triggered up regulation of CCR7 expression and PGE2 production by DC, thus impairing DC migration towards CCL19 in vitro and in vivo. Moreover, ? ray exposed DC also displayed an increased apoptosis rate and decreased cell viability. Furthermore, we demonstrate that exogenous PGE2 can partly reduce the gamma-ray induced migratory impairment and restored CCR7 expression of DC. Our work suggests that ? irradiation affects DC function at multiple steps during the immune response including DC migration, and that PGE2, via control of CCR7 expression, is an important regulator of DC migration. PMID:21383953

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

2011-01-01

361

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

International Nuclear Information System (INIS)

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

362

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

Science.gov (United States)

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.

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

2007-02-01

363

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

364

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

International Nuclear Information System (INIS)

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

365

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)

366

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

367

Gamma ray attenuation measurements  

International Nuclear Information System (INIS)

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

368

Gamma ray camera  

International Nuclear Information System (INIS)

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

369

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

International Nuclear Information System (INIS)

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

370

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

371

Gamma-ray irradiation effects on InAs/GaSb-based nBn IR detector  

Science.gov (United States)

IR detectors operated in a space environment are subjected to a variety of radiation effects while required to have very low noise performance. When properly passivated, conventional mercury cadmium telluride (MCT)-based infrared detectors have been shown to perform well in space environments. However, the inherent manufacturing difficulties associated with the growth of MCT has resulted in a research thrust into alternative detector technologies, specifically type-II Strained Layer Superlattice (SLS) infrared detectors. Theory predicts that SLS-based detector technologies have the potential of offering several advantages over MCT detectors including lower dark currents and higher operating temperatures. Experimentally, however, it has been found that both p-on-n and n-on-p SLS detectors have larger dark current densities than MCT-based detectors. An emerging detector architecture, complementary to SLS-technology and hence forth referred to here as nBn, mitigates this issue via a uni-polar barrier design which effectively blocks majority carrier conduction thereby reducing dark current to more acceptable levels. Little work has been done to characterize nBn IR detectors tolerance to radiation effects. Here, the effects of gamma-ray radiation on an nBn SLS detector are considered. The nBn IR detector under test was grown by solid source molecular beam epitaxy and is composed of an InAs/GaSb SLS absorber (n) and contact (n) and an AlxGa1-xSb barrier (B). The radiation effects on the detector are characterized by dark current density measurements as a function of bias, device perimeter-to-area ratio and total ionizing dose (TID).

Cowan, Vincent M.; Morath, Christian P.; Swift, Seth M.; Myers, Stephen; Gautam, Nutan; Krishna, Sanjay

2011-01-01

372

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

International Nuclear Information System (INIS)

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

373

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)

374

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

International Nuclear Information System (INIS)

Cadmium sulfide quantum dots 1.3–5.6 nm in size have been synthesized in sodium bis(2-ethylhexy1)sulfosuccinate (AOT)–water–isooctane micellar solutions with various [H2O]/[AOT] molar ratios (w=2.5, 5.0 or 10). Gamma irradiation method has been used to change the size and optical properties of quantum dots. It has been found that ?-irradiation reduces the size polydispersity of quantum dots in the micellar system and alters their fluorescent properties. Fluorescence intensity is enhanced after ?-irradiation. The average fluorescence lifetime of single quantum dots sized 5.2±0.4 nm increases from 5.14 to 6.39 ns after ?-irradiation at a dose of 7.9 kGy. To the best of our knowledge, this is the first report on fluorescence lifetime of single CdS quantum dots in micellar solution. - Highlights: • Gamma irradiation method has been used successfully to change the size and optical properties of CdS quantum dots synthesized in micellar solutions. • ?-Irradiation reduces the size polydispersity of quantum dots in the micellar system. • Fluorescence intensity of CdS quantum dots is enhanced after ?-irradiation. • Fluorescence lifetime of single CdS quantum dots increases after ?-irradiation

375

The effect of embryonal thymic calf extracts on neonatally thymectomized mice and on mice lethally irradiated with gamma rays  

International Nuclear Information System (INIS)

The effect of embryonal thymic calf extracts (ETCE) on mice thymectomized at birth was investigated. ETCE was found to induce an increase in leukopenia and decrease in the level of serum gamma globulins; it also reduced survival time in mice. The effect of ETCE on lethally irradiated mice was also examined. Only long-term administration of ETCE prior to gamma irradiation at 750 rad prolonged the survival time of mice (40% permanent survival) as compared with irradiated controls; the leukocytes from mice retained mitotic capability. Neither long-term treatment with ETCE prior to irradiation at 1000 rad, nor short-term administration prior to 750 rad affected survival time. ETCE administered after irradiation of mice with 750 rad caused a rapid decrease in blood leukocytes and a significantly lowered survival time. (Auth.)

376

Effect of gamma-ray irradiation on the sorption property of hydrous ferric oxide and ferric phosphate  

International Nuclear Information System (INIS)

The equilibrium sorption capacity of hydrous ferric oxide and ferric phosphate has been observed to increase on irradiation with ?-rays by 5.2 and 6.6%, respectively. The rate of sorption increases differently in the irradiated exchanger materials depending upon their characteristic nature: e.g., when the concentration of the Zn/ammine/ solution is 0.10M, increase in the F-values, caused by irradiation is significantly more striking in the case of hydrous ferric oxide than in ferric phosphate. On the other hand, at lower external concentration of the Zn/ammine/ ion /0.01M/, the increase in F-values is more significant in the case of ferric phosphate. No definite conclusion was achieved on the possible structural changes caused in the irradiated exchange materials except that the materials exhibited an amorphous character. (T.G.)

377

Gamma ray optics  

Science.gov (United States)

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

Jentschel, M.; Günther, M. M.; Habs, D.; Thirolf, P. G.

2012-07-01

378

Gamma ray camera  

Science.gov (United States)

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

Perez-Mendez, V.

1997-01-21

379

A study on the effect of 60Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (4)  

International Nuclear Information System (INIS)

The last report was to make it clear that the abrasion quantity of the SF and SH specimens treated with 60Co ?-rays irradiation was less than 1/5 of that of non-treated specimens (Kimura et al. 1981). Reported in this article is the cross-linking effect by irradiation of neutron beam in lieu of 60Co ?-ray in an attempt to improve P.M.M.A. in terms of abrasion resistance and scratch resistance of the specimen, as in the case of 60Co ?-rays irradiation. Experiment of irradiation of neutron beam of 5.4 x 1013 n/cm2.sec. for 1 - 20 minutes was carried out, but it was found that brittlizing progressed along with hardening and it was hard to expect improvement in scratch resistance with the coated material for cross-linking used in the experiment of this time, except the case of irradiation for 4 minutes where slight improvement in cross-linking reinforcement may be expected. (author)

380

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

International Nuclear Information System (INIS)

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)

381

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

Science.gov (United States)

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

Ito, Hitoshi; Islam, Md. Shamsul

1994-06-01

382

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, cesults 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

383

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

384

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

International Nuclear Information System (INIS)

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

385

Reaction mechanisms in ? irradiated high surface silica-elastomer systems  

International Nuclear Information System (INIS)

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

386

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-04-15

387

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

388

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

International Nuclear Information System (INIS)

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

389

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1986-04-01

390

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

International Nuclear Information System (INIS)

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

391

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

Energy Technology Data Exchange (ETDEWEB)

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

Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2014-07-01

392

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

Science.gov (United States)

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

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

2014-07-01

393

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

International Nuclear Information System (INIS)

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

394

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

International Nuclear Information System (INIS)

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

395

Gamma Ray Bursts  

Science.gov (United States)

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

Gehrels, Neil; Meszaros, Peter

2012-01-01

396

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

International Nuclear Information System (INIS)

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

397

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)

398

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

International Nuclear Information System (INIS)

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

399

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

OpenAIRE

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 th...

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

2013-01-01

400

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

OpenAIRE

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 stu...

Fares, S.

2012-01-01

401

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

International Nuclear Information System (INIS)

The tebo worms or butterworms (Chilecomadia moorei) are widely used in Chile in fishing, and so are in the international markets although there are some countries, that use these species, to a less extent for preparing food reptiles. Some foreign countries requirements demand, from the exporters, to carry out quarantine treatments related to the sterilization by ionizing energy, however customers need to make sure about their products safety and that is why it is compulsory to establish limits in connection with worms' irradiation resistance. The irradiation effect on a worms sample using doses of 0.3; 0.45; 0.6 and 0.9 kGy was studied macroscopically, after 1 hour, and then 30, 60 and 90 days after the treatment. One of the equipment utilized had a Cobalt 60 source, where as the other one had Cesium 137 irradiators, with a dose rate of 42.7 Gy minute (min)-1 and 37.1 Gy min-1, respectively. The results concluded that tebo worms can resist more than 3 times the dos