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1

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

CERN Document Server

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

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

2005-01-01

2

Gamma-ray spectroscopy on irradiated fuel rods  

International Nuclear Information System (INIS)

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

2009-10-02

3

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

4

Visualization of pool boiling with gamma ray irradiation  

International Nuclear Information System (INIS)

The surface wettability changes highly hydrophilic conditions after irradiation of 60Co gamma ray, but the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of RISA on boiling phenomena, CHF of metal oxides irradiated by gamma rays were investigated. The heating test section made of titanium was 0.5mm in diameter. Oxidation of the surface carried out by plasma jetting. The test section was irradiated by 60Co gamma ray with predetermined radiation intensity and period. A test piece had been hold horizontally on the electrode after 5400kGy irradiation. Then, the whole CHF test apparatus with test piece was set on the table in the gamma ray irradiation room. The test piece was irradiated in the water at least 30 minutes. A CHF experiment in the pool boiling condition was carried out under atmospheric pressure under irradiation. The results of on-site experiment were compared with that of off-site one. (author)

2004-12-01

5

Effects of gamma ray irradiation on sensitivity of photochromic glasses  

International Nuclear Information System (INIS)

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

1978-01-01

6

Irradiated thermoplastic elastomer  

International Nuclear Information System (INIS)

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

1977-01-25

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

Influence of gamma ray irradiation on metakaolin based sodium geopolymer  

Science.gov (United States)

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

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

2013-11-01

9

Gamma ray-irradiation in fresh allo-joint transplantation  

Energy Technology Data Exchange (ETDEWEB)

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

Watanabe, Hiroshi [Yamanashi Medical Coll., Tamaho (Japan)

1995-09-01

10

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)

2004-06-01

11

Grafting study of polysulfone polymeric membranes by gamma ray irradiation  

International Nuclear Information System (INIS)

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

2011-10-16

12

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

13

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

International Nuclear Information System (INIS)

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

2010-06-01

14

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

1974-12-09

15

Induced parthenocarpy with pollen irradiated with gamma rays  

International Nuclear Information System (INIS)

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

1975-01-01

16

Degradation behavior of poly (L-lactide-co-glycolide) films through gamma-ray irradiation  

International Nuclear Information System (INIS)

Gamma-ray irradiation is a very useful tool to improve the physicochemical properties of various biodegradable polymers without the use of a heating and crosslinking agent. The purpose of this study was to investigate the degradation behavior of poly (L-lactide-co-glycolide) (PLGA) depending on the applied gamma-ray irradiation doses. PLGA films prepared through a solvent casting method were irradiated with gamma radiation at various irradiation doses. The irradiation was performed using 60Co gamma-ray doses of 25–500 kGy at a dose rate of 10 kGy/h. The degradation of irradiated films was observed through the main chain scission. Exposure to gamma radiation dropped the average molecular weight (Mn and Mw), and weakened the mechanical strength. Thermograms of irradiated film show various changes of thermal properties in accordance with gamma-ray irradiation doses. Gamma-ray irradiation changes the morphology of the surface, and improves the wettability. In conclusion, gamma-ray irradiation will be a useful tool to control the rate of hydrolytic degradation of these PLGA films. - Highlights: ? The degradation behavior of PLGA depending on the radiation dose is investigated. ? The main degradation mechanisms by radiation seem to be a main chain scission. ? Radiation can be a potential tool to control the rate of degradation.

2012-07-01

17

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

18

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

International Nuclear Information System (INIS)

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

1987-06-05

19

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

20

Effects of Gamma Irradiation on EPDM Elastomers.  

Science.gov (United States)

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 t...

E. A. Clark

2011-01-01

 
 
 
 
21

Gamma-ray irradiation effects on dynamic gain of erbium-doped fiber amplifiers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Experiments were made of the gamma-ray irradiation effect on the dynamic performance of erbium-doped fiber amplifiers (EDFAs). The frequency responses of EDFAs before and after irradiation are dependent on radiation dose and modulation frequency. The ac gain of EDFA with irradiation effect was also simulated, and our simulations are in agreement with the experimental results.

Jau-Ji Jou; Cheng-Kuang Liu; Fu-Shun Lai

2010-01-01

22

Mechanical properties of material for reactor coolant pump seal irradiated with gamma ray  

Energy Technology Data Exchange (ETDEWEB)

The variations of flexural strength, toughness and density of alumina used as reactor coolant pump mechanical seal were measured after gamma ray irradiation of 10 Mrad which was the equivalent of 10 year irradiation of reactor coolant pump in operation. After irradiation of gamma ray the changes of toughness, and density were negligible in case of 99.7 wt% alumina. After irradiation and stay in 100 .deg. C water for 48 hour, the flexural strength of the alumina reduced a little. This change of flexural strength was expected to be resulted from the dissolution of silicate located between alumina granules by 100 .deg. C water.

Lee, H. J.; Kim, K. B.; Cho, H. D.; Park, J. Y. [KAERI, Taejon (Korea, Republic of)

2001-10-01

23

Mechanical properties of material for reactor coolant pump seal irradiated with gamma ray  

International Nuclear Information System (INIS)

The variations of flexural strength, toughness and density of alumina used as reactor coolant pump mechanical seal were measured after gamma ray irradiation of 10 Mrad which was the equivalent of 10 year irradiation of reactor coolant pump in operation. After irradiation of gamma ray the changes of toughness, and density were negligible in case of 99.7 wt% alumina. After irradiation and stay in 100 .deg. C water for 48 hour, the flexural strength of the alumina reduced a little. This change of flexural strength was expected to be resulted from the dissolution of silicate located between alumina granules by 100 .deg. C water

2001-10-01

24

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

2006-02-01

25

Results on neutron and gamma-ray irradiation of electrolytic tiltmeters  

International Nuclear Information System (INIS)

We report on irradiation studies done to a sample of high-precision electrolytic tiltmeters with gamma-rays, up to a maximum dose of 150 kGy, and neutrons, up to a maximum fluence of 1.5x1014 cm-2. The effect of the irradiation on their performance is discussed

2004-10-21

26

Results on neutron and gamma-ray irradiation of electrolytic tiltmeters  

Energy Technology Data Exchange (ETDEWEB)

We report on irradiation studies done to a sample of high-precision electrolytic tiltmeters with gamma-rays, up to a maximum dose of 150 kGy, and neutrons, up to a maximum fluence of 1.5x10{sup 14} cm{sup -2}. The effect of the irradiation on their performance is discussed.

Calderon, A. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Calvo, E. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Figueroa, C.F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Martinez-Rivero, C. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Matorras, F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Rodrigo, T. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Vila, I. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Virto, A.L. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Arce, P. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Barcala, J.M. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Ferrando, A. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain)]. E-mail: antonio.ferrando@ciemat.es; Fuentes, J. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Josa, M.I. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Luque, J.M. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Molinero, A. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Navarrete, J. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Oller, J.C. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Valdivieso, P. [CIEMAT, Fisica de particulas, Edificio 2, Avda. Complutense 22, E-28040 Madrid (Spain); Fenyvesi, A. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary); Molnar, J. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary)

2004-10-21

27

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

International Nuclear Information System (INIS)

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

1985-02-01

28

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)

1980-02-15

29

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

Science.gov (United States)

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

Fujimoto, Mari; Takeda, Mayuko; Okamoto, Kouji; Furuta, Masakazu

2011-02-01

30

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

International Nuclear Information System (INIS)

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

2011-02-01

31

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

International Nuclear Information System (INIS)

Data on the shortening of the life span in mice by radiation show that an acute dose of gamma-rays may be as much as four times as effective as an equal dose of the same radiation administered chronically. However, for neutrons, chronic and acute administrations are equally effective. An analysis of these effects shows that for gamma-rays a certain fraction of the radiation injury is reparable, and that the value of this fraction depends on the dose and the dose rate. With neutrons, none of the damage appears reparable. For acute irradiation, the RBE is about 2 for shortening of the life span, but for chronic, may be as high as 8. Chromosome aberrations have been scored in liver cells of mice when treated with both chronic and acute doses of both gamma-rays and thermal neutrons. In all cases the percentage of aberrent cells is proportional to the shortening of the life span produced by the treatment. Further, with neutrons, acute and chronic irradiation is equally effective in producing chromosome abberations. For gamma-rays, acute irradiation may produce as much as four times the chromosomal damage as does chronic irradiation. This shows that some chromosomes can heal themselves following small doses of gamma-rays, but there is no chromosome healing following any dose of neutrons. The RBE using chromosome aberrations as a criterion is the same as for life shortening. These results give a firm cellular basis for the known biological differences between gamma rays and neutrons, and in addition give strong support to the concept that natural and radiation-induced aging are caused by spontaneous and radiation-induced mutations, respectively, in the somatic cells of animals. (author)

1964-05-01

32

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

International Nuclear Information System (INIS)

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

2008-08-12

33

Biological effects of (60)Co (gamma)-ray irradiation on lymphocyte chemoluminescence.  

Science.gov (United States)

Utilizing lymphocyte chemiluminescence technique, the biological effects of (sup 60)Co (gamma)-ray irradiation on lymphocyte chemiluminescence (Ly-CL) stimulated with PHA or ConA in vitro were investigated. The results showed: (1) 0.25 Gy (sup 60)Co (gamm...

Z. Mao X. Su

1991-01-01

34

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

CERN Document Server

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

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

2003-01-01

35

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1989-01-01

36

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)

1979-01-01

37

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

38

Coloring of cultured pearls by gamma-rays irradiation  

International Nuclear Information System (INIS)

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

1985-01-01

39

Ultrastructural changes of cell organelles in gamma-ray irradiated arabidopsis thaliana L  

International Nuclear Information System (INIS)

Low and high doses of ionizing radiation were used to stimulate or inhibit seed germination, plant growth, size and productivity. However, Ultrastructure of plant cell is not well known about the effects of irradiation on the plant cell. The morphological changes are attributed to the biological changes of different tissues and cell organelles. The aim of this study is to compare the ultrastructural changes in cellular organelles of stems of Arabidopsis after prolonged gamma-ray irradiation from low and high doses

2004-10-28

40

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)

2009-10-02

 
 
 
 
41

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

International Nuclear Information System (INIS)

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

1991-01-01

42

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

International Nuclear Information System (INIS)

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

1993-09-19

43

Reduction of active nucleation site density under gamma ray irradiation  

International Nuclear Information System (INIS)

nucleation site density decreased with increasing dose. The several nucleation sites have been deactivated under the irradiation condition. The rate of bubble separation from the test piece decreases as the dose increases. The decrease of heat transfer by reduction of active nucleation site density causes the shift of boiling curve to higher wall superheat temperature. The reduction of active nucleation site density is considered to be explained by the wettability increase under irradiation, i.e. RISA effect. (author)

2005-09-01

44

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

International Nuclear Information System (INIS)

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

2008-05-01

45

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

1983-01-01

46

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

International Nuclear Information System (INIS)

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

1982-01-01

47

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

48

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

49

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)

1989-01-01

50

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

International Nuclear Information System (INIS)

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

2009-06-01

51

Glasses, Coatings, Glues and Gamma-ray Irradiation  

International Nuclear Information System (INIS)

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

2001-01-01

52

Glasses, Coatings, Glues and Gamma-ray Irradiation  

Energy Technology Data Exchange (ETDEWEB)

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

Barcala, J.M.; Fernandez, M. G.; Ferrando, A.; Fuentes, J.; Josa, M. I.; Molinero, A.; Oller, J. C. [Ciemat. Madrid (Spain); Arce, P.; Calvo, E.; Figueroa, C. F.; Rodrigo, T.; Vila, I.; Virto, A. L. [Universidad de Cantabria. Santander (Spain); Beigveder, J. M.; Genova, I.; Perez, G.; Ruiz, J. A. [CIDA. Madrid (Spain)

2001-07-01

53

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

1986-12-16

54

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

International Nuclear Information System (INIS)

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

2002-12-01

55

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-12-01

56

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

International Nuclear Information System (INIS)

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

2001-01-01

57

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.)

1990-01-01

58

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1990-11-01

59

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

International Nuclear Information System (INIS)

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

1998-11-24

60

Decontamination of salmonella from the coastal fish meals by /sup 60/Co. gamma. ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

The decontamination of salmonellae from fish meal samples by irradiation which /sup 60/Co ..gamma.. ray was examined. Sixteen strains of Salmonella were used. A composite fish meal sample was prepared by mixing with different coastal meals, and after radiation sterilization at a dose of 20 kGy /sup 60/Co ..gamma.. ray, which was employed as the salmonella-free meal sample. D/sub 10/ values of test strains determined in buffered saline were found to range from 0.08 to 0.36 kGy, and inactivation factors at a dose of 1 kGy ranged from 10/sup 2.8/ to 10/sup 13/. D/sub 10/ values of test strains determined in the salmonella-free meal sample ranged from 0.59 to 1.64 kGy, and the inactivation factors at a dose of 10 kGy were found to range from 10/sup 6.1/ to 10/sup 17/. Interestingly the D/sub 10/ values of salmonellae determined in fish meal samples were 10 times as much compared with those determined in buffered saline. From the commercial aspects of coastal fish meal production, destruction of salmonellae in fish meals by /sup 60/Co ..gamma.. ray irradiation was found to be much more practical than other methods such as dry heating and ethylene oxide fumigation.

Saheki, Kazuaki; Konno, Kenjiro; Sato, Takae; Kawabata, Toshiharu.

1988-12-01

 
 
 
 
61

Characterization of silver nanoparticle in the carboxymethyl cellulose hydrogel prepared by a gamma ray irradiation.  

Science.gov (United States)

In this study, carboxymethyl cellulose (CMC) hydrogels were traditionally prepared by gamma-ray with an absorbed dose of 50 kGy from a 60Co source. The CMC hydrogels were absorbed and swelled in silver nitrate aqueous solution (0.01 M) by dipping for 1 hour, and then irradiated by gamma-ray at various doses to form silver nanoparticles (Ag NPs). The UV-Vis analysis indicated that the concentration of Ag NPs was enhanced by increasing of absorbed dose from 1 to 5 kGy in this situ reducing system. The FE-SEM and XPS measurements provided further evidence for the successful formation of Ag NPs. These CMC hydrogels stabilized Ag NPs also have been investigated for inhibiting the growth of Staphylococcus aureus and Escherichia coli strains in liquid as well as on solid growth media. The antibacterial tests indicated that the hydrogels containing Ag NPs have antibacterial activity. PMID:22524050

Park, Jong-Seok; Kuang, Jia; Lim, Youn-Mook; Gwon, Hui-Jeong; Nho, Young-Chang

2012-01-01

62

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

International Nuclear Information System (INIS)

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

2008-09-01

63

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 10"2 to 10"6 R/h, and at temperature ranging from -40degC to 100degC. The following results were obtained. (1) 2SB603: Changes of the DC gain and leak current are larger in low exposure rate irradiations, and large exposure rate dependency is observed. The DC gain change is based on mainly increase of the base current. The exposure rate dependency is observed in the reverse saturation current and voltage, but in the switching time. (2) 2SC764: The exposure rate and temperature dependencies on irradiation effect are not clear, and the radiation resistance is over two orders higher than 2SB603 in the various properties. (3) 2SK458: The exposure rate and temperature dependencies on irradiation effect are small. (4) Irradiation effect on 2SB603 by electron beams is smaller than that by gamma-rays, and the exposure rate effect is observed. No difference between electron beams and gamma rays is observed for 2SC764 and 2SK458. (author)

1989-01-01

64

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

International Nuclear Information System (INIS)

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

2012-10-01

65

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

Energy Technology Data Exchange (ETDEWEB)

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

Kudoh, H.; Kasai, N.; Sasuga, T.; Seguchi, T. (Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment)

1994-04-01

66

method of fabricating gamma ray irradiation source filled in a plastic tube  

International Nuclear Information System (INIS)

Purpose: To fabricate gamma ray irradiation source with safety and effectively by filling target substances and spacers in a cylindrical covering material made of radiation resistant plastics and then mounting the tube into a radiation resistant irradiation capsule for radioactivation. Constitution: Each types of targets are previously filled together with fine wire spacers made of radiation resistant plastics in the covering material made of radiation resistant fine plastic tube, and the tube is filled within a radiation resistant plastic irradiation capsule. Then, by the irradiation of neutron rays, each of the targets can be activated. Various forms of targets can be used such as elemental metals, alloys and compounds depending on purposes of use and experiments. After the irradiation of the neutron rays, the polyethylene covering material and the nylon fine wire are not denatured by the radiation damages and the fabrication can be conducted with safety and effectively. (Seki, T.)

1981-01-01

67

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-11

68

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 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.)

1980-01-01

69

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

International Nuclear Information System (INIS)

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

2008-04-01

70

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.)

2000-02-01

71

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

International Nuclear Information System (INIS)

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

1984-11-19

72

Mechanical strength at 4. 2 K of organic composite materials irradiated with. gamma. -rays  

Energy Technology Data Exchange (ETDEWEB)

In the present work, four kinds of epoxy matrix composites (including G-10CR and G-11CR) and a polyimide matrix composite were irradiated with /sup 60/Co ..gamma..-rays at room temperature, and were examined with regard to the mechanical strength at 4.2 K. This work demonstrated that one of the epoxy matrix composites is superior to the polyimide matrix composite in terms of the mechanical strength at 4.2 K in a dose range up to at least 70 MGy. The present report mainly describes the dose dependence of the mechanical strength at 4.2 K for these composites. (orig./RK).

Egusa, S.; Hagiwara, M.; Nakajima, H.; Oshikiri, M.; Shimamoto, S.

1986-01-01

73

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

International Nuclear Information System (INIS)

LHC, working at the expected nominal luminosity, will induce an extremely high irradiation in the CMS experiment. The CMS alignment system uses optical elements to build the laser beams paths. Optical properties of basic components such as glasses and glues may be affected and their transmission power may degrade significantly. We have proceeded to a first test of various glasses and glues and identified some of them that can stand up to 150 kGy of gamma-rays plus 5x1014 neutrons/cm2

2002-11-11

74

Influence of gamma-ray irradiation on 6H-SiC MOSFETs  

International Nuclear Information System (INIS)

Enhancement-type n-channel MOSFETs were fabricated on 6H-SiC epitaxial films using pyrogenic or dry oxidation process. Oxide-trapped charges and interface traps produced in 6H-Sic MOSFETs by gamma-ray irradiation are evaluated from changes in the subthreshold-current curve. The net numbers of radiation-induced-oxide-trapped charges and interface traps depend on the oxidation process. The 6H-SiC MOSFETs exhibit higher radiation resistance than Si MOSFETs. (author)

1998-10-01

75

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.)

1985-01-01

76

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.

2010-01-01

77

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

International Nuclear Information System (INIS)

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

1986-01-01

78

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 kR but not at higher doses. The number of 'stunted roots' showed a further increase when treated with IAA and IBA. (author)

1976-01-01

79

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS  

Energy Technology Data Exchange (ETDEWEB)

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

Clark, E.

2011-09-22

80

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

International Nuclear Information System (INIS)

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

2008-09-21

 
 
 
 
81

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 10"7R, but there was a slight deterioration up to 10"6R. (4) Comparing the result of the mechanical properties, the strengths of the various sheets were shown in the following order: the sheet irradiated after paper making gt the sheet irradiated before beating (air dry state) gt the sheet irradiated before beating (wet state). (author)

1980-01-01

82

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)

2006-05-01

83

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

International Nuclear Information System (INIS)

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

2009-01-01

84

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

85

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

International Nuclear Information System (INIS)

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

2010-12-01

86

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

87

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

International Nuclear Information System (INIS)

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

2002-02-01

88

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

International Nuclear Information System (INIS)

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

1994-01-01

89

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

International Nuclear Information System (INIS)

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

2014-05-01

90

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

2002-03-01

91

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

International Nuclear Information System (INIS)

Twenty years of the works on the chronic gamma-ray irradiation of seed crops are summarized. Radiosensitivity and the mutation rate per unit exposure varies not only with the genetic factor but also depend on whether treatment is given to seeds or growing plants. The relation between the radiosensitivity of seeds and growing plants also varies with plant species. In Hordeum, Avena and Nicotiana, the highest mutation rate obtained by the chronic irradiation of growing plants is similar to that in seed irradiation, but in Oryza and Setalia, chronic irradiation was two to three times more effective for attaining a higher mutation rate. The mutation spectrum also varies with the mutagen, the factors modifying the effects of mutagen, and the dose of mutagen. The suitability of a particular mutagenic treatment to a species should be taken into consideration in the evaluation of mutagenic treatment. For instance, NaN3 is highly mutagenic to barley, but less mutagenic to rice. The gene ea7 controlling the maturing earliness of barley seems to be mutable in chronic irradiation, and the mutants obtained by chronic irradiation are healthy. The author emphasized that the chronic irradiation at the gamma-field is a useful mutagenic treatment, even though some negative results have been reported in European countries. (Kaihara, S.)

1983-01-01

92

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

Directory of Open Access Journals (Sweden)

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

Pejovi? Mili? M.

2013-01-01

93

Teratogenic effects of /sup 60/Co gamma rays irradiation on rat embryos  

Energy Technology Data Exchange (ETDEWEB)

The teratogenicity of /sup 60/Co 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 LD/sub 50/ in rats. Pregnant rats were irradiated with a /sup 60/Co 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 ..gamma.. rays in inducing congenital malformations. The RBE for incidence of malformations and LD/sub 50/ 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, with respect to RBE of tritium beta rays.

Lee, Juing-Yi; Okuda, Hiroe; Tutimoto, Sigeo; Satow, Yukio

1987-01-01

94

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-02-15

95

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

International Nuclear Information System (INIS)

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

1976-01-01

96

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-01-01

97

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

2002-10-01

98

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

International Nuclear Information System (INIS)

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

1995-03-01

99

Gamma ray irradiation behavior of fission products in nitric acid solution  

International Nuclear Information System (INIS)

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

1991-01-01

100

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

International Nuclear Information System (INIS)

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

2008-01-01

 
 
 
 
101

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

Science.gov (United States)

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

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

102

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

International Nuclear Information System (INIS)

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

2009-10-02

103

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

International Nuclear Information System (INIS)

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

1992-05-01

104

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-09-01

105

Dependence of gamma-ray dose on annihilation processes of irradiation defects in Li2TiO3  

International Nuclear Information System (INIS)

Dependence of gamma-ray dose on formation and annihilation behaviors of irradiation defects was studied by means of ESR. In the formation behavior of irradiation defects, the amount of irradiation defects and ratio of O2--center to O--center increased as the in gamma-ray dose increased. The annealing experiments showed that the amounts of E'-center and O-related defects which are the Frenkel pair decreased in the two temperature ranges of 300-400 and 550-650 K. The first and second stages were identified to reactions between E'-center and O--center and E'-center and O2--center, respectively. By comparing annihilation with formation behaviors of irradiation defects, it was revealed that the activation energy of annihilation for irradiation defects was influenced by the ratio of O2--center and O-related defects. Therefore, the annihilation process of irradiation defects was dominated by pyrolysis of O2--center.

2011-10-01

106

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

International Nuclear Information System (INIS)

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

1991-01-01

107

Preparation of gel polymer electrolyte for lithium secondary battery by {gamma}-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

In this study, gel polymer electrolytes were prepared by an in situ copolymerization of acrylonitrile (AN) and methyl methacrylate (MMA) in the presence of a crosslinking agent (polyethylene glycol dimethyl methacrylate(PEGDMA)) and liquid electrolyte (1 M LiClO{sub 4} ethylene carbonate (EC)/propylene carbonate (PC) (1/1, v/v)) using a {gamma}-ray irradiation. Their thermal and mechanical properties were investigated by using Dynamic Mechanical Analyzer (DMA) and Universal Test Machine (UTM). It was found that the addition of crosslinker enhanced mechanical properties due to network formation in gel polymer electrolyte. Ionic conductivities of the prepared gel polymer electrolyte were strongly related to the ratio of monomer/liquid electrolyte and the contents of MMA and PEGDMA. The prepared gel polymer electrolytes showed sufficient electrochemical stabilities of up to 4.5 V by linear sweep voltammetry test.

Sohn, Joon Yong; Im, Jong Su; Shin, Jun Hwa; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2009-12-15

108

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

International Nuclear Information System (INIS)

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

1992-03-01

109

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-11-01

110

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

International Nuclear Information System (INIS)

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

1994-09-02

111

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

Science.gov (United States)

Experimental studies for sterilizing 12 kinds of soy sauce with gamma-ray irradiation showed that both of effects for sterilization and improving flavour and quality of soy sauce were obtained simultaneously. All colibacillus in soy sauce were sterilized using 1 kGy radiation dose and total bacteria count in soy sauce can be reduced to below national standard at 5 kGy dose ( 5x10 4count/ml ). But above 10 kGy dose is needed to kill all bacteria in soy sauce. The significant changes on chemical components in soy sauce irradiated at 5-7 kGy dose took place: raduceing-sugar increased by 1-10%, total amount of 18 kinds of free amino acid raised between 3.5-28 %, emerging-sweet smell substances which have low boiling point, such as alchols, aldehydes and esters obviously increased. The taste-specialists from some soy sauce factories concluded that flavour and quality of soy sauce irradiated are better than non-irradiated.

Jingtian, Yang; Xinhua, Jin; Guoxing, Gu; Guichun, Yun

112

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-12-01

113

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

International Nuclear Information System (INIS)

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

2009-09-01

114

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

Directory of Open Access Journals (Sweden)

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

115

Observations on the effect of irradiation by gamma rays on the absorption and fluorescence of anthracene and phenanthrene  

International Nuclear Information System (INIS)

The absorption and fluorescence spectra of anthracene and phenanthrene in various solvents were recorded after they were irradiated with gamma rays. The siqnificant observations are critically discussed. Some peculiar features observed in the fluorescence spectra of anthracene in carbon tetrachloride have been attributed to the formation of dimers. (auth.)

1979-01-01

116

Muscular fibrosis induced after pig skin irradiation with single doses of [sup 192]Ir [gamma]-rays  

Energy Technology Data Exchange (ETDEWEB)

Localized irradiation of the skin and subcutaneous tissues with large single doses of [gamma]-rays can induce delayed effects characterized by fibrosis which invades the irradiated tissues. In this study the depth of penetration of muscle fibrosis was measured in the pig 30 weeks after irradiation of the skin surface with single doses of [sup 192]Ir [gamma]-rays of 16-256 Gy. Irradiation was directed either to the outer side of the thigh or to the back, close to the mid-dorsal line. Fibrosis only developed in irradiated muscle after doses that induced moist desquamation of the skin in the acute phase of the reaction, i.e. after skin surface doses of 48-64 Gy. In skeletal muscles, the limit of fibrotic expansion was reached at a depth dose of 14[+-]4 Gy ([+-] SD) for skin surface doses exceeding 48 Gy. (author).

Lefaix, J.-L.; Martin, M.; Tricaud, Y.; Daburon, F. (CEA Centre d' Etudes de Saclay, 91 - Gif-sur-Yvette (France). Lab. de Radiobiologie Appliquee)

1993-06-01

117

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, k_1, 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 5.5x10"9 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 H_2O_2 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 H_2O_2 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)

2001-06-01

118

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

Scientific Electronic Library Online (English)

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

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

119

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)

1995-01-01

120

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

International Nuclear Information System (INIS)

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

2001-06-01

 
 
 
 
121

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

122

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)

2009-10-02

123

Levels of 2-dodecylcyclobutanone in ground beef patties irradiated by low-energy X-ray and gamma rays.  

Science.gov (United States)

Food irradiation improves food safety and maintains food quality by controlling microorganisms and extending shelf life. However, acceptance and commercial adoption of food irradiation is still low. Consumer groups such as Public Citizen and the Food and Water Watch have opposed irradiation because of the formation of 2-alkylcyclobutanones (2-ACBs) in irradiated, lipid-containing foods. The objectives of this study were to measure and to compare the level of 2-dodecylcyclobutanone (2-DCB) in ground beef irradiated by low-energy X-rays and gamma rays. Beef patties were irradiated by low-energy X-rays and gamma rays (Cs-137) at 3 targeted absorbed doses of 1.5, 3.0, and 5.0 kGy. The samples were extracted with n-hexane using a Soxhlet apparatus, and the 2-DCB concentration was determined with gas chromatography-mass spectrometry. The 2-DCB concentration increased linearly (P patties. There was no significant difference in 2-DCB concentration between gamma-ray and low-energy X-ray irradiated patties (P > 0.05) at all targeted doses. PMID:21535632

Hijaz, Faraj M; Smith, J Scott

2010-01-01

124

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

International Nuclear Information System (INIS)

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

1989-01-01

125

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

126

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

Science.gov (United States)

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 (-CH 2- •CH-CH 2-) was the major product after irradiation in vacuum and in air at room temperature. Some of the alkyl radicals converted to allyl radicals (-CH 2- •CH-CH=CH-) and polyenyl radicals (-CH 2- •CH-(CH=CH) n-CH 2-) 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.

Zhao, Yanning; Wang, Mouhua; Tang, Zhongfeng; Wu, Guozhong

2010-04-01

127

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

International Nuclear Information System (INIS)

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

2005-01-01

128

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 mutation were distinguished cost-effectively from the grains of the original Koshihikari cultivar in large-scale analysis (author)

2008-08-12

129

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

International Nuclear Information System (INIS)

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

2002-01-01

130

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-10-15

131

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.

2011-10-01

132

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-03-01

133

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

International Nuclear Information System (INIS)

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

2009-06-01

134

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-06-15

135

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

136

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)

2002-10-01

137

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

Science.gov (United States)

An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the D10 value of B. cereus at 4 degrees C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 degrees C. The gamma irradiation of the bacteria without incubation at 4 degrees C before irradiation was more effective than that of the bacteria with incubation overnight at 4 degrees C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 degrees C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. PMID:12638185

Miyahara, Michiko; Miyahara, Makoto

2002-01-01

138

Peroxidation of blood plasma lipids after various regimes of external irradiation of rats by 60Co gamma-rays  

International Nuclear Information System (INIS)

Peroxidation products of lipids in blood plasma of laboratory rats are studied after one-time, fractional and long-term external irradiation of the rats by 60Co gamma-rays. It was found, that different modes of a total external irradiation of rats lead to prominent features of dynamics and dose dependences of radio gene changes of the content of peroxidation products of lipids in blood plasma. It was shown that fractional irradiation is less effective for an organism, whereas long-term irradiation causes essentially big radiation induced changes than one-time action of radiation.

2009-01-01

139

Study on the effect of /sup 60/Co gamma ray irradiation on the abrasion of dental polymethylmethacrylate, (3)  

Energy Technology Data Exchange (ETDEWEB)

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 /sup 60/Co 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 /sup 60/Co gamma ray would give the best results at the exposure at 1 x 10/sup 6/ R. The SF and SH specimens in wet condition exposed to /sup 60/Co gamma ray irradiation at 1 x 10/sup 6/ 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.

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

1981-12-01

140

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

 
 
 
 
141

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-01-01

142

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

International Nuclear Information System (INIS)

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

1984-01-01

143

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

2005-06-01

144

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

International Nuclear Information System (INIS)

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

1993-06-04

145

Dose-mortality relationships in RFM mice following /sup 137/Cs. gamma. -ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

The effect of single-exposure /sup 137/Cs ..gamma..-ray irradiation on overall and tumor-specific mortality is examined using data from a large study of RFM mice conducted at the Oak Ridge National Laboratory. The use of a proportional-hazards regression technique leads to the exploration and quantification of mortality rates as a function of both radiation dose and animal age. Relative risks for most mortality types were found to be predominantly linear as a function of dose and were found to decrease markedly with increasing time since exposure. An exception occurs with ovarian cancer. Rates of mortality with ovarian cancer increase very sharply and nonlinearly for doses as low as 50 rad. Further, the increased ovarian cancer relative risks do not appear to decline as the animals age. In spite of rather different overall relative risks for male and female mice at particular doses the age-specific relative risks are rather similar, thereby giving a unified dose-response model for all natural causes of mortality. Implications of these analyses for low-dose extrapolation are mentioned.

Prentice, R.L.; Peterson, A.V.; Marek, P.

1982-04-01

146

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 varieties to the Ministry of Agriculture. (author)

2011-12-01

147

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

International Nuclear Information System (INIS)

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

2008-09-01

148

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

International Nuclear Information System (INIS)

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

1980-01-01

149

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

International Nuclear Information System (INIS)

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

1982-02-01

150

An atomic force microscopic study of the surfaces of polyethylene and polycarbonate films irradiated with gamma rays  

Energy Technology Data Exchange (ETDEWEB)

The changes in the surface topology of polyethylene and polycarbonate films irradiated with gamma rays up to 500 kGy doses have been investigated with Atomic Force Microscopy. The cumulative effect of irradiation has been followed by analyzing exactly the same region of the surfaces after every irradiation step. This has been achieved by applying an addressing operation on the surfaces of virgin polymers. The increase in surface roughness showed a sudden increase up to100 kGy dose and remained almost unchanged thereafter. The radiation-induced topological changes are found to correlate with the chemical effects of these rays. (author).

Guven, O. [Hacettepe Univ., Ankara (Turkey); Alacakir, A.; Tan, E. [Ankara Nuclear Research and Training Center (Turkey)

1997-08-01

151

An atomic force microscopic study of the surfaces of polyethylene and polycarbonate films irradiated with gamma rays  

International Nuclear Information System (INIS)

The changes in the surface topology of polyethylene and polycarbonate films irradiated with gamma rays up to 500 kGy doses have been investigated with Atomic Force Microscopy. The cumulative effect of irradiation has been followed by analyzing exactly the same region of the surfaces after every irradiation step. This has been achieved by applying an addressing operation on the surfaces of virgin polymers. The increase in surface roughness showed a sudden increase up to100 kGy dose and remained almost unchanged thereafter. The radiation-induced topological changes are found to correlate with the chemical effects of these rays. (author)

1997-08-01

152

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2005-01-01

153

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

154

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

Science.gov (United States)

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

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

2009-07-01

155

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-11-01

156

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

International Nuclear Information System (INIS)

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

2005-07-25

157

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

International Nuclear Information System (INIS)

The new nanodosimetry-based linear-quadratic (LQ) formula has been reviewed for mixed-LET irradiation. V-79 Chinese hamster cells have been irradiated with a mixed-LET field of fission neutrons and gamma rays at University of Maryland Training Reactor (MUTR). The results show that the experimental survival curve agrees well with that predicted by the new nanodosimetry-based LQ model. The experimental study described in this note, therefore, serves as a validation for the new model to be used for mixed-LET radiotherapies, e.g. 252Cf brachytherapy

2007-09-07

158

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

International Nuclear Information System (INIS)

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

1986-01-01

159

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

Energy Technology Data Exchange (ETDEWEB)

The radiation-induced changes in the volume electrical conductivities of chemical vapor deposited silicon carbides (CVD-SiCs) were in-site investigated by performing irradiation using 1.17 and 1.33-MeV gamma-ray and 14-MeV fast neutron beams in air and vacuum. Under gamma-ray irradiation at ionization dose rates of 3.6 and 5.9 Gy/s and irradiation temperature of approximately 300 K, the initial rapid increase in electrical conductivity; this is indicative of radiation-induced conductivity (RIC), occurred due to electronic excitation, and a more gradual increase followed up to a dose of approximately 10-50 kGy corresponding to the results in base conductivity without radiation; this is indicative of radiation-induced electrical degradation (RIED). However, the radiation-induced phenomena were not observed at irradiation temperatures above 373 K. Under neutron irradiation at a further low dose rate below approximately 2.1 Gy/s, a fast neutron flux of 9.2 x 10{sup 14} n/m{sup 2} s, and 300 K, the RIED-like behavior according to radiation-induced modification of the electrical property occurred with essentially no displacement damage, but ionizing effects (radiolysis).

Tsuchiya, Bun, E-mail: btsuchiya@meijo-u.ac.jp [Department of General Education, Faculty of Science and Technology, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya 468-8502 (Japan); Shikama, Tatsuo; Nagata, Shinji; Saito, Kesami [Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yamamoto, Syunya [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233, Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Ohnishi, Seiki [Tokai Research and Development Center, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Nozawa, Takashi [Aomori Research and Development Center, Japan Atomic Energy Agency, 2-166, Omotedate, Obuchi, Rokkasho, Aomori 039-3212 (Japan)

2011-10-15

160

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)

2008-06-01

 
 
 
 
161

Comparative effect of gamma-rays and ultraviolet irradiation on sensitivities and mutation induction of escherichia coli  

Energy Technology Data Exchange (ETDEWEB)

Three strains of Escherichia coli, B1, B2 and B/r were irradiated with {gamma}-rays and ultraviolet rays. E. coli B1 and B2 were isolated from E. coli B. They were inoculated on either Tryptone agar or Glucose-NH{sub 4} agar plates to observe the comparative sensitivities to the irradiations. UV irradiation was more effective for the inactivation of cells than {gamma}-rays irradiation in all strains when compared at the same absorbed energy. The sensitivities to the irradiations were in the order of E. coli B1, B2 and B/r by both irradiations. Higher sensitivities were observed when inoculated on Glucose-NH{sub 4} agar plates than on Tryptone agar plates. Induction of mutation was also studied on lac{sup -}mutant and auxotroph. MacConkey agar plates were used to distinguish the lac{sup -}mutant from the wild type; the mutant showed whitish colonies compared to the reddish purple colonies by wild type. Auxotroph was distinguished from the wild type which formed colonies on Glucose-NH{sub 4} agar plate, while the auxotroph colonies were made after adding casamino acid onto Glucose-NH{sub 4} agar plates. Induction of lac{sup -}mutant and auxotroph by {gamma}-irradiation was the most frequent in E. coli B/r when compared at the same survival fraction of 10{sup -4}. Induction of mutation occurred more frequently by {gamma}-irradiation than by UV-irradiation, and more stable mutants were obtained by {gamma}-irradiation. (J.P.N.).

Takigami, Machiko; Ito, Hitoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1995-09-01

162

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

International Nuclear Information System (INIS)

over the generations in 20Gy gamma rays + 1.00% EMS treatment. From the study it was inferred that sudden exposure of materials causes more lethality with poor field establishment and the chance of occurrence of mutants were comparatively lesser. (author)

2008-08-12

163

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-12-31

164

Effects of high-temperature anneals and 60Co gamma-ray irradiation on strained silicon on insulator  

Science.gov (United States)

Strained silicon on insulator was exposed to high-temperature annealing and high-dose 60Co gamma (?)-ray irradiation to study the tenacity of the bond between the strained Si film and the underlying buried oxide. During the high-temperature anneals, the samples were ramped at a rate of 150°C/s to 850°C then ramped to 1200, 1250, and 1300 °C at a rate of approximately 5×105 °C/s for millisecond duration anneals. For the irradiation experiments, the samples were irradiated with 60Co ? rays to a dose of 51.5 kGy. All samples were characterized by ultraviolet (UV) Raman, pseudo metal-oxide-semiconductor field-effect transistor (?-MOSFET) current voltage, Hall mobility, and photoluminescence (PL) to verify changes in strain. UV Raman, PL, and ?-MOSFET measurements show no strain relaxation for the high-temperature annealed samples and only very slight relaxation for the ?-ray irradiated samples.

Park, K.; Canonico, M.; Celler, G. K.; Seacrist, M.; Chan, J.; Gelpey, J.; Holbert, K. E.; Nakagawa, S.; Tajima, M.; Schroder, D. K.

2007-10-01

165

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

Energy Technology Data Exchange (ETDEWEB)

Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by [gamma]-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H[sub 50] according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from [sup 40]K contained in the samples. (author).

Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Shibata, Setsuko; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

1994-02-01

166

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)

1980-01-01

167

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-04-01

168

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

International Nuclear Information System (INIS)

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

2005-04-01

169

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

International Nuclear Information System (INIS)

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

2003-04-07

170

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)

1998-02-18

171

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

172

Gamma-ray measurement and calculation from proton-irradiated materials  

Science.gov (United States)

Many of the fundamental questions regarding the formation of planetary bodies and the evolution of their crust can be addressed by the measurement of the global elemental composition of their surface by remote sensing gamma-ray spectroscopy. However, in order to determine the absolute chemical concentration on a planet, highly precise ground-based experiments and computer simulation is essential. In the case of the moon, Apollo mission provides "ground truth" and mission data can be normalized to elements found in the returned sample such as Fe, Ti, and Mg. It is also known from the ground truth that Si and O are basically independent from the sampled location. But those data are gained at limited points of the entire surface to be observed. As for other planets, there would be no such reference data. Computer simulation will play very important role to compensate for the lack of ground truth and to determine the concentration. Therefore its consistency has to be verified with the ground-based experiments. Fluxes of gamma-rays and neutrons emitted from target materials (0.5m x 0.5m 0.5m Fe and Al, and 0.7m x 0.7m x 0.7m stone) bombarded by 210 MeV protons were calculated by using Monte Carlo simulation library, Geant4. Those results are compared with experimental values gained from accelerator beam exposure. For Fe, the number of gamma-rays in peaks detected by the 113 cc Ge detector were consistent with calculation within the error of ~5%. The comparison between numerically calculated data and experimental results will help improve the precision of lunar observation by Gamma-Ray Spectrometer on board Japanese lunar polar orbiter SELENE, to be launched in 2005.

Yamashita, N.

173

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

International Nuclear Information System (INIS)

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

2005-01-01

174

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

1978-01-01

175

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

176

Effects of gamma-ray irradiation and sodium sulfate on the IGSCC susceptibility of sensitized Type 304 stainless steel in high-temperature water  

International Nuclear Information System (INIS)

This paper reports the effects of gamma- ray irradiation and sodium sulfate as an aqueous impurity on the intergranular stress corrosion cracking (IGSCC) susceptibility of sensitized type 304 (UNS(1) S30400) stainless steel (SS) studied through slow strain rate tests (SSRT) and corrosion potential measurements in high- temperature water that simulated the BWR normal water chemistry (NWC) and hydrogen water chemistry (HWC) conditions. The SSRT results demonstrated that IGSCC was accelerated by gamma-ray irradiation under the NWC condition, while it was suppressed under the HWC condition. These different effects are attributable to the radiation-induced corrosion potential shifts in the opposite directions depending on the water chemistry condition. When the sodium sulfate as injected up to 0.32?S/cm of conductivity, IGSCC was observed even under the HWC condition, but it was suppressed by gamma-ray irradiation

1990-01-01

177

Effects of gamma-ray irradiation and sodium sulfate on the IGSCC susceptibility of sensitized Type 304 stainless steel in high-temperature water  

Energy Technology Data Exchange (ETDEWEB)

This paper reports the effects of gamma- ray irradiation and sodium sulfate as an aqueous impurity on the intergranular stress corrosion cracking (IGSCC) susceptibility of sensitized type 304 (UNS{sup (1)} S30400) stainless steel (SS) studied through slow strain rate tests (SSRT) and corrosion potential measurements in high- temperature water that simulated the BWR normal water chemistry (NWC) and hydrogen water chemistry (HWC) conditions. The SSRT results demonstrated that IGSCC was accelerated by gamma-ray irradiation under the NWC condition, while it was suppressed under the HWC condition. These different effects are attributable to the radiation-induced corrosion potential shifts in the opposite directions depending on the water chemistry condition. When the sodium sulfate as injected up to 0.32{mu}S/cm of conductivity, IGSCC was observed even under the HWC condition, but it was suppressed by gamma-ray irradiation.

Saito, N.; Ichikawa, N.; Hemmi, Y. (Nuclear Engineering Lab., Toshiba Co., 4-1 Ukishima-cho Kawasaki-ku, Kawasaki-shi 210 (JP)); Sudo, A.; Itow, M.; Okada, T. (Isogo Engineering Center, Toshiba Co., 8 Shinsugita-cho Isogo-ku Yokohama-shi 235 (JP))

1990-07-01

178

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

International Nuclear Information System (INIS)

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

2010-05-01

179

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

International Nuclear Information System (INIS)

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

1988-01-01

180

Instability of Langmuir waves in plasma irradiated by directed gamma rays  

International Nuclear Information System (INIS)

In this Letter we investigate the possibility of Langmuir turbulence generation by directed gamma rays penetrating a background plasma. Turbulence is generated because Compton scattering creates superthermal electrons whose distribution can be unstable to the Cherenkov radiation of Langmuir waves. Using the Klein-Nishina cross section for relativistic Compton scattering, we calculate the momentum distribution of recoil electrons and derive the increment of instability for nonmagnetized plasma. The instability appears when there is a sufficiently narrow bump, for example, annihilation line h?=mec2 with a width less than 0.3mec2, in the gamma spectrum

1995-03-20

 
 
 
 
181

The correlation between the bonding properties of ligands and the irradiation effects of gamma-rays on iron compounds  

International Nuclear Information System (INIS)

Various iron compounds have been irradiated with gamma-rays of cobalt-60. The foreign-charge states of the irradiated compounds were confirmed by means of Moessbauer spectroscopy. The results showed that high-spin iron(III) compounds with large conjugated molecules and low-spin iron(II) compounds are insensitive to ?-radiations. However, iron(III) compounds with carboxyl groups or reducing ligands and low-spin iron (III) compounds are sensitive to ?-radiations. Further, FeCl2.4H2O was found to be insensitive to radiation up to a total exposure dose of 109 R, in contrast to other ionic iron(II) compounds. (author)

1981-01-01

182

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

183

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

International Nuclear Information System (INIS)

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

2008-01-01

184

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

International Nuclear Information System (INIS)

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

2012-05-01

185

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

186

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

Science.gov (United States)

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

Sporea, Dan; Sporea, Adelina; Oproiu, Constantin

2013-12-01

187

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

International Nuclear Information System (INIS)

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

2003-08-01

188

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

International Nuclear Information System (INIS)

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

2010-12-01

189

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

190

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

Directory of Open Access Journals (Sweden)

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

Jieyu Yue

2012-05-01

191

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

Energy Technology Data Exchange (ETDEWEB)

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

Okudera, Akihiro; Sawai, Hiroko; Endoh, Eiji; Oshiba, Susumu (Nihon Univ., Tokyo. School of Medicine)

1982-10-01

192

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-07-01

193

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

194

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

International Nuclear Information System (INIS)

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

2005-02-11

195

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 Ag_2SO_4 in the media. Irradiation of 10-20 Gy gamma rays on seeds of mungbean walet variety could improved shoot regeneration of explants from node cotyledon. (author)

1998-02-18

196

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

Energy Technology Data Exchange (ETDEWEB)

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.

Calderon, A. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Calvo, E. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Figueroa, C.F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Martinez-Rivero, C. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Matorras, F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Rodrigo, T. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Sobron, M. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Vila, I. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Virto, A.L. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Arce, P. [CIEMAT, Madrid (Spain); Barcala, J.M. [CIEMAT, Madrid (Spain); Ferrando, A. [CIEMAT, Madrid (Spain)]. E-mail: antonio.ferrando@ciemat.es; Josa, M.I. [CIEMAT, Madrid (Spain); Luque, J.M. [CIEMAT, Madrid (Spain); Molinero, A. [CIEMAT, Madrid (Spain); Navarrete, J. [CIEMAT, Madrid (Spain); Oller, J.C. [CIEMAT, Madrid (Spain); Yuste, C. [CIEMAT, Madrid (Spain)

2005-02-11

197

Radioprotection by dipyridamole. Effects on lipid peroxidation in mouse liver after whole-body X-ray and "6"0Co gamma-ray irradiation  

International Nuclear Information System (INIS)

To investigate the mechanism of the radioprotective effect of dipyridamole, the lipid peroxide content in mouse liver irradiated by X-ray and "6"0Co gamma-ray were measured both before and after injection of dipyridamole. The lipid peroxide content was significantly increased in a time-related manner after whole-body irradiation, and the increase depended on the dose of irradiation. There was no significant difference on biological effects between X-ray and "6"0Co gamma-ray. Dipyridamole given before irradiation significantly inhibited the lipid peroxide increase by whole-body irradiation. The results suggest that inhibition of lipid-peroxidation is a possible factor in the radioprotective effect of dipyridamole. (author)

1994-10-01

198

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

International Nuclear Information System (INIS)

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

2004-01-01

199

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

International Nuclear Information System (INIS)

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

2007-10-01

200

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

Energy Technology Data Exchange (ETDEWEB)

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.

Han, Na-Kyung; Byun, Hae-Ok; Lee, Je-Jung; Lee, Jae-Seon [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chi, Sung-Gil; Ko, Young-Gyu [Korea University, Seoul (Korea, Republic of)

2007-10-15

 
 
 
 
201

Gas Evolution from Insulating Materials for Superconducting Coil of Iter by Gamma Ray Irradiation at Liquid Nitrogen Temperature  

Science.gov (United States)

A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM).

Idesaki, A.; Koizumi, N.; Sugimoto, M.; Morishita, N.; Ohshima, T.; Okuno, K.

2008-03-01

202

GAS EVOLUTION FROM INSULATING MATERIALS FOR SUPERCONDUCTING COIL OF ITER BY GAMMA RAY IRRADIATION AT LIQUID NITROGEN TEMPERATURE  

International Nuclear Information System (INIS)

A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM)

2008-03-03

203

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, 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)

1995-12-01

204

Comparison of effect of gamma ray irradiation on wild-type and N-terminal mutants of ?A-crystallin  

Science.gov (United States)

Purpose To study the comparative structural and functional changes between wild-type (wt) and N-terminal congenital cataract causing ?A-crystallin mutants (R12C, R21L, R49C, and R54C) upon exposure to different dosages of gamma rays. Methods Alpha A crystallin N-terminal mutants were created with the site-directed mutagenesis method. The recombinantly overexpressed and purified wt and mutant proteins were used for further studies. A 60Co source was used to generate gamma rays to irradiate wild and mutant proteins at dosages of 0.5, 1.0, and 2.0 kGy. The biophysical property of the gamma irradiated (GI) and non-gamma irradiated (NGI) ?A-crystallin wt and N-terminal mutants were determined. Oligomeric size was determined by size exclusion high-performance liquid chromatography (HPLC), the secondary structure with circular dichroism (CD) spectrometry, conformation of proteins with surface hydrophobicity, and the functional characterization were determined regarding chaperone activity using the alcohol dehydrogenase (ADH) aggregation assay. Results ?A-crystallin N-terminal mutants formed high molecular weight (HMW) cross-linked products as well as aggregates when exposed to GI compared to the NGI wt counterparts. Furthermore, all mutants exhibited changed ?-sheet and random coil structure. The GI mutants demonstrated decreased surface hydrophobicity when compared to ?A-crystallin wt at 0, 1.0, and 1.5 kGy; however, at 2.0 kGy a drastic increase in hydrophobicity was observed only in the mutant R54C, not the wt. In contrast, chaperone activity toward ADH was gradually elevated at the minimum level in all GI mutants, and significant elevation was observed in the R12C mutant. Conclusions Our findings suggest that the N-terminal mutants of ?A-crystallin are structurally and functionally more sensitive to GI when compared to their NGI counterparts and wt. Protein oxidation as a result of gamma irradiation drives the protein to cross-link and aggregate culminating in cataract formation.

Ramkumar, Srinivasagan; Fujii, Noriko; Fujii, Norihiko; Thankappan, Bency; Sakaue, Hiroaki; Ingu, Kim; Natarajaseenivasan, Kalimuthusamy

2014-01-01

205

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 CO_2 and small amounts of H_2, CH_4, and CO. The G-values of CO_2 were 0.004 for PEN and 0.07 for PET by irradiation under vacuum, and were 0.26 for PEN and 0.17 for PET in oxygen. In the case of irradiation without oxidation, the crosslinking proceeded mainly for PEN, but the chain scission was the main reaction for PET. In the case of oxidative irradiation, the chain scission proceeded and no cross-linking was observed for both PEN and PET. The change of mechanical properties of PEN film irradiated under vacuum was very small by comparing with PET. The radiation resistances of PEN and PET were evaluated to be 12 MGy for PEN and 2 MGy for PET in non-oxidative conditions, and were 4.5 MGy for PEN and 1.4 MGy for PET in oxidation conditions by the measurements of tensile testing. The reason of high radiation resistance of PEN was thought that PEN molecules have a large resonance energy of napthalene in the polymer chain, and have higher probability of crosslinking comparing with PET molecules due to the molecular conformation such as crystalline structure. (author)

1989-01-01

206

Gamma-Ray Irradiation Effects on the Characteristics of New Material P Type 6H-SiC Ni-Schottky Diodes (Application For Nuclear Fuel Facilities)  

International Nuclear Information System (INIS)

Effects of gamma-ray irradiation on electrical characteristics of new material p type 6H-SiC Ni-Schottky diodes were investigated. Ni Schottky diodes fabricated on p type 6H-SiC epi-layer were irradiated with gamma-rays at RT. The electrical characteristics of the diodes were evaluated before and after irradiation. The value of the on-resistance does not change up to 1 MGy, and the value increases with increasing absorbed dose above 1 MGy. For n factor, no significant increase is observed below 500 kGy, however, the value increases above 500 kGy. Schottky Barrier Height (SBH) decreases with increasing absorbed dose. Leakage current tends to increase due to irradiation. (author)

2007-10-01

207

Generation of interface traps and oxide-trapped charge in 6H-SiC metal-oxide-semiconductor transistors by gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Enhancement-type n-channel metal-oxide-semiconductor field effect transistors (MOSFETs) were fabricated on 6H-SiC to investigate the influence of {gamma}-ray irradiation on device characteristics. The net number of radiation-induced oxide-trapped charges and interface traps induced by {gamma}-ray irradiation were {approx}3 x 10{sup 12}/cm{sup 2} and {approx}5 x 10{sup 11}/cm{sup 2} after 70kGy irradiation, respectively. These were measured from changes in the subthreshold-current curve. On comparing the densities of oxide-trapped charges and interface traps produced by irradiation in 6H-SiC MOSFETs with those in Si MOSFETs, the 6H-SiC MOSFETs are found to have high radiation resistance. (author)

Ohshima, Takeshi; Yoshikawa, Masahito; Itoh, Hisayoshi; Aoki, Yasushi; Nashiyama, Isamu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1998-08-01

208

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

International Nuclear Information System (INIS)

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

2001-09-01

209

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-04-26

210

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

Energy Technology Data Exchange (ETDEWEB)

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 CO{sub 2} 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).

Kudoh, H.; Kasai, N.; Sasuga, T.; Seguchi, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1996-11-01

211

Effect of gamma-ray irradiation on the unloaded animal model  

Science.gov (United States)

During the space flight, human beings encountered the extreme conditions such as the cosmic ray irradiation and microgravity. There have been developed the animal models to simulate the microgravity condition in laboratory, but no study was carried out to investigate the combined effect of microgravity and exposure to irradiation. In this study, it was examined the effect of gamma irradiation on the suspension model. Rats were divided into four groups, Group I was loaded and not exposed to gamma irradiation, Group 2 was unloaded and not exposed, Group 3 was loaded and exposed to gamma irradiation at the dose of 50 mSV, and Group 4 was unloaded and exposed to gamma irradiation at the same dose. It was measured body, muscles and tissues weights and the biological analysis and the hematological response in blood samples were conducted. Anti-gravity tissue weight was only changed between loading and un-loading condition. However, there was no difference between irradiation exposed and not exposed unloaded groups. To know the difference of protein expression in anti-gravity tissues, 2 dimensional electrophoresis was performed. It has been found that the expression levels of several proteins were different by unloading condition and by irradiation exposed condition, respectively. These results provided the information on the combined effect of irradiation and microgravity to simulate space flight, and could be useful to search the candidate material for the countermeasure against space environment.

Choi, Jong-Il; Yoon, Min-Chul; Sung, Nak-Yoon; Kim, Jae-Hun; Jong Lee, Yun; Lee, Ki-Soo; Choi, In-Ho; Nam, Gung Uk; Lee, Ju-Woon

212

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

International Nuclear Information System (INIS)

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

1993-01-01

213

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%).

2013-01-11

214

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

215

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)

1998-07-01

216

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

International Nuclear Information System (INIS)

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T.thynnus, were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips

2010-03-01

217

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

Energy Technology Data Exchange (ETDEWEB)

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T.thynnus, were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips.

Choi, Jong Il; Kim, Yeon Joo; Kim, Jae Hun; Yoon, Yo Han; Song, Beom Seok; Lee, Ju Woon [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Chun, Byung Soo; Ahn, Dong Hyun [Pukyong National University, Busan (Korea, Republic of); Lee, Ju Yeoun [Chonbuk National University, Jeonju (Korea, Republic of)

2010-03-15

218

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

International Nuclear Information System (INIS)

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

2012-07-01

219

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.)

1984-01-01

220

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)

2002-08-11

 
 
 
 
221

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-07-01

222

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

International Nuclear Information System (INIS)

About 20000 ophidic accidents are registered every year in Brazil. Serum therapy with equine antisera is the only efficient treatment. The venoms employed for immunization are fairly toxic and some venoms present low immunogenicity. Thus, the obtention of modified antigens with lower toxicity and preserved or improved immunogenicity would be useful. These toxins, when submitted to gamma radiation, in aqueous solution, present structural modifications. This occurs due to reactions with the radiolysis products of water. Some scavenger substances, such as NaNO3 and t-butanol, remove selectively the water radiolysis products. Ionizing radiation has proven to be a powerful tool to attenuate snake venoms toxicity without affecting and even increasing their immunogenic properties. However, the immune mechanisms involved in recognition, processing and presentation of irradiated antigens are yet unclear. In the present work, we investigated the immunological behavior of bothropstoxin-I (Bthx-1), before and after irradiation, in the presence of selective scavengers. Isogenic mice were immunized with either the native or the irradiated toxin, either with or without scavengers. After three immunizations, serum samples were collected and the antibody titers and isotypes were determined by Enzyme Linked Immuno Sorbent Assay. The antigenic characterization of native and irradiated bothropstoxin-I was performed by Western blot. The detection of expression of murine cytokines (IFN-? and IL-10) was analyzed by RT-PCR (Reverse Transcriptase-Polymerase Chain Reaction). According to our data, irradiation process has promoted structural modifications in the toxin, characterized by higher molecular weight forms of the protein (aggregates and oligomers). Our data also indicate that irradiated toxins, alone or in the presence of NaNO3, an aqueous electron scavenger, were immunogenic and the antibodies elicited by them were able to recognize the native toxin. On the other hand, when the toxin was irradiated in presence of t-butanol, a discrete reduction in antibodies levels was observed, suggesting a role of hydroxyl radicals in the modulation of immune response. Irradiated bothropstoxin-1 elicited antibodies responsive to both toxins forms, as demonstrated by Western blot. The cytokines profiles indicated that IFN-? mRNA presence appeared to be higher for mice immunized with irradiated toxin, while IL-10 mRNA presence was predominant with the antigen in its native form. These results indicate that irradiation of proteins leads to significant structural modifications, and also to a modulation of the immunological response. (author)

2007-10-05

223

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

224

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)

1993-06-01

225

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.)

1999-02-01

226

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)

1988-04-24

227

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

228

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

International Nuclear Information System (INIS)

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

2008-08-12

229

Irradiation and gamma-ray spectrometric parameters for "1"2"9I neutron activation analysis  

International Nuclear Information System (INIS)

This paper describes the influence of reactor neutron irradiation facilities on low-level "1"2"9I 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 "1"2"9I and natural iodine and interference effects due to high levels of "1"2"7I 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 "1"2"9I is given

1984-01-01

230

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

International Nuclear Information System (INIS)

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

1992-03-01

231

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

Energy Technology Data Exchange (ETDEWEB)

Crack propagation tests in 288{degrees}C water were carried out using a 1/4 size compact tension specimen of sensitized Type 304 stainless steel (stress intensity; 25 MPa{radical}m) under {gamma}-ray irradiation (Co-60) with high fluxes of 1.3-2.3 x 10{sup 3} C/kgh. The intergranular SCC crack growth was slightly accelerated by {gamma}-ray irradiation were at most twice as large as that in unirradiated water. The crack growth rates increased almost linearly with increasing Na{sub 2}SO{sub 4} concentration in irradiated water containing more than 500 ppb dissolved oxygen (DO); in the 900 ppb DO condition, the crack growth rate of 2.6 x 10{sup 9} m/s in water containing 0.4 {mu}S/cm Na{sub 2}SO{sub 4} was about 5 times larger than that in high purity water of 0.07 {mu}S/cm. Although the NaNO{sub 3} addition also enhanced the crack propagation in 500 ppb DO water, NaNO{sub 3} was less harmful than Na{sub 2}SO{sub 4} in water. Hydrogen injection of 300-500 ppb into water was beneficial to prevent SCC crack propagation in 288{degrees}C water during {gamma}-ray irradiation.

Nakata, K.; Shimanuki, S.; Anzai, H.; Mabuchi, K.; Fuse, M.; Shigenaka, N. [Hitachi Ltd., Ibaraki-ken (Japan)

1992-12-31

232

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-02-01

233

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-03-01

234

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

International Nuclear Information System (INIS)

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

2007-10-01

235

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-07-01

236

Gamma-ray astronomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Pohl, Martin

2001-01-01

237

Gamma ray generator  

Energy Technology Data Exchange (ETDEWEB)

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

238

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

International Nuclear Information System (INIS)

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

2006-09-23

239

Response of two sesame cultivars to seed irradiation with gamma rays  

International Nuclear Information System (INIS)

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

1993-01-01

240

Effect of dissolved oxygen on corrosion behavior of stainless steel in gamma ray irradiation environment  

International Nuclear Information System (INIS)

Experimental data on corrosion behavior of stainless steel in actual BWR primary environment under irradiated field are lacking in literature, because the personnel access and maintenance for the experiment are difficult. The corrosion test loop, which had two test sections set inside and outside of the irradiation test room, was used to do the work successfully. The tests were performed by control of water quality in two typical BWR corrosion environments, namely normal water chemistry (NWC) and hydrogen water chemistry (HWC). Corrosion products released from the main loop construction material, type 316 stainless steel, and corrosion potentials of test coupons, type 304 stainless steel, were measured. And the corrosion oxide films formed on the coupons were characterized. The corrosion behaviors of the austenitic stainless steels were affected by the corrosion environment, which was determined by both of the water chemistry condition, NWC or HWC, and radiolysis of water

1987-09-03

 
 
 
 
241

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

International Nuclear Information System (INIS)

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

1989-01-01

242

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

International Nuclear Information System (INIS)

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

1987-01-01

243

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

International Nuclear Information System (INIS)

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

1979-01-01

244

Thermoluminescence of CsCl:Ce crystals irradiated with gamma rays  

International Nuclear Information System (INIS)

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

1993-01-01

245

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

International Nuclear Information System (INIS)

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

1983-01-01

246

Method for the degradation of dibutyl phthalate in water by gamma-ray irradiation  

International Nuclear Information System (INIS)

The degradation and mineralization of dibutyl phthalate (DBP), one of endocrine disruptors, by ?-ray irradiation were demonstrated. The degradation was enhanced by the effective energy conversion of ?-rays to low-energy electrons and photons with the assistance of the interactions between ?-rays and metals, which is especially in the case of high Z materials effective. Numerical simulations using EGS code supported the experimental results. Improvements of the energy conversion process are also suggested by controlling the shape of the metal and its spatial configuration in the DBP solution. (author)

2003-02-01

247

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

Science.gov (United States)

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

Matsson, I; Grapengiesser, B; Andersson, B

2007-01-01

248

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

International Nuclear Information System (INIS)

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

2006-09-23

249

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-06-15

250

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.

2008-09-21

251

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)

1995-03-01

252

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)

2013-08-01

253

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

International Nuclear Information System (INIS)

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

1997-01-01

254

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

International Nuclear Information System (INIS)

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

2007-01-01

255

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

International Nuclear Information System (INIS)

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

2005-03-01

256

Gamma ray irradiation characteristics of Ge-doped silica optical fibers  

International Nuclear Information System (INIS)

Optical fibers have the various excellent characteristics such as light weight, noninductivity, insulation and so on, accordingly it can be said that they are most suitable to the treansmission of information which has become complicated and high grade recently. However, when optical fibers are used in radiation environment, color centers are formed in the raw material glass, and the transmission loss increases. Accordingly, in order to use them in radiation environment like nuclear power plants, it is necessary to study beforehand on the optical characteristics of the fibers affected by radiation. In this study, as for the radiation resistance of three kinds of the optical fibers with different Ge content, the measurement of loss wavelength characteristics using a white light source, the measurement of transmission characteristics using a monochromatic light source, and the measurement of color centers by ESR were carried out, and the relationship among these characteristics was investigated. The fibers put to the tests, the experimental method and the results are reported. The transmission loss was the least in GI-2, and some restoration of the loss after irradiation was observed in GI-1 and GI-2. It seems that GAC took part in the transmission loss. (K.I.)

1991-01-01

257

Gamma ray irradiation characteristics of Ge-doped silica optical fibers  

Energy Technology Data Exchange (ETDEWEB)

Optical fibers have the various excellent characteristics such as light weight, noninductivity, insulation and so on, accordingly it can be said that they are most suitable to the treansmission of information which has become complicated and high grade recently. However, when optical fibers are used in radiation environment, color centers are formed in the raw material glass, and the transmission loss increases. Accordingly, in order to use them in radiation environment like nuclear power plants, it is necessary to study beforehand on the optical characteristics of the fibers affected by radiation. In this study, as for the radiation resistance of three kinds of the optical fibers with different Ge content, the measurement of loss wavelength characteristics using a white light source, the measurement of transmission characteristics using a monochromatic light source, and the measurement of color centers by ESR were carried out, and the relationship among these characteristics was investigated. The fibers put to the tests, the experimental method and the results are reported. The transmission loss was the least in GI-2, and some restoration of the loss after irradiation was observed in GI-1 and GI-2. It seems that GAC took part in the transmission loss. (K.I.).

Okawa, Osamu; Midera, Hisamitsu; Hayashi, Yoshinori; Mimura, Yoichi; Nakano, Hiroshi (Niigata Univ. (Japan)); Tsunoda, Tsunemi

1991-12-01

258

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

1971-01-01

259

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

International Nuclear Information System (INIS)

The stoichiometry and radiolytic products of ZnSe(Te,O) crystals before and after irradiation were investigated by instrumental X-ray radiometric and neutron activation analysis of the elemental composition. ZnSe single crystals as-grown, doped with Te, treated in oxygen or a reducing atmosphere and Zn vapours were studied for a comparison. Doping with Te, whose ionic radius is larger than in Se, resulted in the production of V(Se) or V(Zn) structure vacancies. Treatment in oxygen resulted in a partial substitution of Se by smaller O ions giving rise to interstitial Sei or Zni atoms. Treatment in Zn vapour produced extra Zni and V(Se). To generate different kinds of structure defect pairs, the samples were exposed to 60CO 1.25 MeV gamma quanta at doses of 5x105 to 2x109 R at 1000 R/s and temperatures of 80 and 350 K, and separately, to thermal and fast (> 3 MeV) neutron fluxes accompanied by gamma-radiation in a nuclear reactor at fluences of 1016 and 1017 cm-2 at 350 K, and also to 18 MeV protons at a fluence of 1015 cm-2 at 300 K. A comparison between the irradiation with thermal and fast neutrons, charged particles (protons and electrons) and uncharged particles (gamma rays, neutrons) can reveal the difference between the defect production mechanisms and modify the structure. All samples had an as-grown super-stoichiometry of Zn: about 49 % Se and 51 % Zn, while the theoretical stoichiometric ratio in ZnSe is 54.7 % Se and 45.53 % Zn. Such non-stoichiometry makes the surface layer less dense and Zn-enriched. Indeed, analyzing the matter removed from the sample surface, the compound of 70-90 % Zn and 10-30 % Se was determined for different samples. When doping with 0.5 % Te, the impurity was found to be distributed unevenly over the bulk, with two maxima roughly at 0.5 % and 0.25 %. At lower doping levels, Te was distributed evenly. During gamma irradiation, 50-60 % Zn and 40-50 % Se were emitted from the surface. The remaining part of the radiolytic product, removed from the surface mechanically after the irradiation, procedure also had a nearly stoichiometric composition. Moreover, the higher was the irradiation dose, the lower was the loss by radiolysis. When exposed to fast neutrons up to 1016 cm-2, Zn ions were mostly emitted, and at the total flux of 5.4x1016 cm-2, Zn and Se were emitted in the stoichiometric ratio and the scintillating properties deteriorated substantially. The same picture was observed in the layer removed from the irradiated surface. When thermal neutrons were used for irradiation, the behaviour was different and the degradation became significant at a higher fluence (1017 cm-2). Bombardment with high energy protons at a dose of 1015 cm-2 in a vacuum led to permission of super-stoichiometric Zn from the exposed surface and some improvement of the surface and scintillating properties. In conclusion, the non-stoichiometric ion emission and radiolysis of sub-surface layer are responsible for the degradation of the scintillator; a suitable proper radiation treatment, on the other hand, can improve the structure and the characteristics, which is a beneficial positive result of irradiation

2002-03-01

260

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

 
 
 
 
261

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 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.

2007-10-17

262

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

International Nuclear Information System (INIS)

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

2004-02-01

263

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

International Nuclear Information System (INIS)

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

1999-01-01

264

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-02-01

265

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

International Nuclear Information System (INIS)

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

2002-05-01

266

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-05-01

267

Study on the effect of dry seed irradiation with gamma rays in low doses (Co60 and Cs137) on the lucerne economic qualities  

International Nuclear Information System (INIS)

Tests with the lucerne varieties Pleven 1, Dounavka and Du Puits are carried out in 1967-1973 at the Forage Institute, Pleven. Air dried seeds of the above varieties were irradiared at 500 - 2000 R. Under the experimental conditions the doses Co60 and Cs137 did not substantially affect the seed germination, rate of growth, initiation of more important phenophases, dry matter yield and its protein content. Some stimulating effect was observed regarding the seed yield. The same is expressed as a complex interaction between the radiation source, irradiation dose, variety, duration of irradiated seed storage and weather conditions during the growing season of the lucerne crop. The gamma rays Co60 and Cs137 exert a strongest stimulating effect on the number of flowers and pods per plant and number of seed per pod. A quantitative change of these indices corresponds to the seed yield. A stimulating effect is more strongly manifested on crops grown from seeds stored for three years and in growing seasons with more favourable conditions for seed production. A dose of 1000 R shows highest stimulating effect at irradiation of previous year seeds of the Dounavka variety (most widely distributed in Bulgaria) with Cs137. The gamma-rays doses studied did not show a stimulating effect at pre-sowing treatment of previous year seeds of the Du Puits lucerne variety. (author)

1975-01-01

268

High Energy Gamma Rays  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article reviews the present status of high energy gamma-ray astronomy at energies above 30 MeV. Observations in the past decade using both space- and ground-based experiments have been primarily responsible for giving a tremendous boost to our knowledge of the high energy Universe. High energy gamma-rays have been detected from a wide range of Galactic and extragalactic astrophysical sources, such as gamma-ray bursters, pulsars, and active galaxies. These observations h...

Mukherjee, R.

2000-01-01

269

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

International Nuclear Information System (INIS)

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

2007-01-01

270

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

International Nuclear Information System (INIS)

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

1988-01-01

271

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

International Nuclear Information System (INIS)

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

1987-01-01

272

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

2010-06-01

273

Gamma ray detector shield  

Science.gov (United States)

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

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

1985-08-26

274

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.)

1980-01-01

275

Indirect genotoxic effect of gamma rays in human peripheral lymphocytes  

International Nuclear Information System (INIS)

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

2001-03-01

276

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

Scientific Electronic Library Online (English)

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

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

277

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-04-15

278

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

International Nuclear Information System (INIS)

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

2003-04-01

279

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

International Nuclear Information System (INIS)

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

1998-04-01

280

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.

2012-06-01

 
 
 
 
281

Effect of Dissolved oxygen on intergranular stress corrosion cracking of sensitized SUS304 in high temperature water under [gamma]-ray irradiation. Gamma sen shoshaka koon suichu ni okeru eibinka SUS304 no ryukaigata oryoku fushokuware  

Energy Technology Data Exchange (ETDEWEB)

Discussions were given on effects of [gamma]-ray irradiation on stress corrosion cracking sensitivity of sensitized SUS 304 in high-temperature water of 288[degree]C under varied dissolved oxygen. Effects of deaeration and hydrogen injection were also discussed. The result may be summarized as follows: Under no [gamma]-ray irradiation, transformation of crystalline particles and ductile fracture faces are observed, Under the [gamma]-ray irradiation, all of the particles developed fracture faces and the stress corrosion cracking increased. The corrosion potential was -50 mV before the irradiation, which rises gradually after beginning the irradiation up to 200 mV. It returned to -50 mV when the irradiation was ceased. Decreased dissolved oxygen reduced the intergranular stress corrosion cracking sensitivity as in the case of no irradiation. However, the particles that did not show the sensitivity under deaerated condition without an irradiation showed the sensitivity when irradiated. Hydrogen injection resulted in no whatever sensitivity. Decomposition products in high-temperature water under the irradiation are H2O2 and O2 which increase with increasing dissolved oxygen. These facts lead to a belief that increase in the sensitivity (corrosion reaction) as a result of the irradiation is because of rise in the corrosion potential as a result of production of oxidizers. 10 refs., 13 figs., 1 tab.

Shimanuki, S.; Nakata, K.; Anzai, H. (Hitachi Ltd., Tokyo (Japan))

1992-12-01

282

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, B, 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 INAA. 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. Only Cd(-) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. (author) 54 refs.; 3 tables

1987-07-01

283

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

International Nuclear Information System (INIS)

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

1981-01-01

284

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)

2006-06-01

285

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

Science.gov (United States)

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.

Kaya, Senol; Aktag, Aliekber; Yilmaz, Ercan

2014-01-01

286

Gamma-ray bursters  

International Nuclear Information System (INIS)

Even with limited amount of available information, astronomers have recently begun to come to a concensus on what the general characteristics of a gamma-ray burst must be. It is centered around three basic points: that a gamma-ray burster system contains a neutron star, that this neutron star has an intense magnetic field, and that most of the observed bursters are situated within our own Milky Way galaxy. It may be possible in the future to determine precisely what causes a gamma-ray burst. 7 figures

1985-01-01

287

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

International Nuclear Information System (INIS)

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

1980-01-01

288

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

International Nuclear Information System (INIS)

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

2008-07-01

289

Gamma ray auto absorption correction evaluation methodology  

International Nuclear Information System (INIS)

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

2010-05-26

290

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)

2006-09-11

291

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

International Nuclear Information System (INIS)

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

1994-01-01

292

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

1975-07-07

293

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

294

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

International Nuclear Information System (INIS)

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

1979-01-01

295

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)

1986-01-01

296

Backscattered dose perturbation effects at metallic interfaces irradiated by high-energy X- and gamma-ray therapeutic beams  

Energy Technology Data Exchange (ETDEWEB)

Purpose: to analyze backscattered dose enhancements near different metallic interfaces for cobalt-60 ({sup 60}Co) gamma rays and 6- and 18-MV photon beams. Material and methods: measurements were carried out with a PTW thin-window, parallel-plate ionization chamber and an RDM-1F electrometer. Thin sheets of aluminum, mild steel, copper, cadmium and lead were used as inhomogeneities. The chamber was positioned below the inhomogenities with the gantry maintained under the couch. Results: it can be noticed that the backscatter dose factor (BSDF) reaches the saturation value within few millimeters of all inhomogeneities and the thickness at which the saturation value is reached depends on the atomic number of the inhomogeneity. The amount of backscattered radiation was noticed to be greater with lesser-energy photons ({sup 60}Co) compared to the higher-energy photons. The BSDF varies across the beam when the inhomogeneity is present due to the change in beam quality. The backscattered electrons from lead inhomogeneity have a range in the order of 5-7 mm. Conclusion: higher atomic number inhomogeneities result in an increase in BSDF, as they have higher scattering cross section for the secondary electrons. The increase in dose was noticed for few millimeters upstream from the metallic inhomogeneity, which suggests that the range of backscattered electrons is very small. Since the factors affecting the BSDF at the interface are energy-dependent, it is expected that the variation in BSDF will also be sensitive to the beam energy. (orig.)

Ravikumar, M.; Ravichandran, R.; Sathiyan, S.; Supe, S.S. [Dept. of Radiation Physics, Kidwai Memorial Inst. of Oncology, Bangalore (India)

2004-03-01

297

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-03-01

298

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 "1"3"7Cs ?-rays at 0.4-1.2 mGy/hr. We found that TD50 values in mice irradiated with a total dose of 250 mGy were increased compared to non-irradiated mice. These results suggested that the low dose-rate irradiation increased, under certain conditions, the tumor cell rejecting ability in mice. (author)

2005-03-01

299

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

300

Gamma ray camera  

Science.gov (United States)

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

Perez-Mendez, Victor (Berkeley, CA)

1997-01-01

 
 
 
 
301

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

302

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)

1998-05-01

303

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-02-01

304

Hypernuclear gamma rays  

Energy Technology Data Exchange (ETDEWEB)

The observation of hypernuclear ..gamma.. rays pprovides a method of determining the spin dependence of the ..lambda..-nucleon interaction with a sensitivity not approachable by other means in the forseeable future. The transitions of primary interest are those between states that differ only in the orientation of the spin of the ..lambda.. particle with respect to the angular momentum of the nuclear core. The effective ..lambda..-nucleon interaction can be specified by a small number of ..gamma..-ray measurements. A program of experiments directed at this goal is in progress at Brookhaven National Laboratory. This paper reviews the status of the subject with emphasis on the recent experiment to measure ground state doublet splittings using germanium ..gamma..-ray detectors.

May, M.

1985-01-01

305

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-10-01

306

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

Science.gov (United States)

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

Tsuchiya, B.; Kondo, S.; Tsurui, T.; Toh, K.; Nagata, S.; Shikama, T.

2011-10-01

307

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

International Nuclear Information System (INIS)

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

1990-01-01

308

Radiosensitivity, mutation and tetraploid induction in the gamma-ray-irradiated growing shoots in mulberry, Morus alba L  

International Nuclear Information System (INIS)

The vigorously developing mulberry shoots on the 1 year old grafted trees of the variety Inchinose were separately exposed to 60Co ?-ray of 6KR at 120 R/hr and 7.5 KR at 150 R/hr in early July, early August and early September. After the irradiation, all of the irradiated shoots developed axially buds with malformed narrow leaves, and after that, all plants subjected to the irradiation in September and 30% of the July irradiation group and 40% of the August irradiation group both with higher exposure ceased shoot development. This type of radiation damage was large for the plants with higher exposure as compared with those with lower one, and it was also severe for the plants irradiated in July in comparison with those in August. From the ceasing of shoot development the LD50 value of 150 R/hr irradiation was estimated to be a little more than 7.5 KR. The frequencies of mutation and tetraploid in the grafts produced by the propagation of the axially buds below the leafless portion were high in the grafts with higher exposure than those with lower one, and also the frequencies were high in July irradiation in comparison with August irradiation. It was confirmed that the size of mutation or tetraploid sector was large in the shoots derived from the less advanced axially bud primordia at the time of irradiation than that from the advanced ones. All of tetraploids were the cytochimeras having diploid epidermises over tetraploid internal tissues. (Kobatake, H.)

1976-01-01

309

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

310

Gamma Ray Bursts  

CERN Document Server

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

Gehrels, Neil; 10.1126/science.1216793

2012-01-01

311

A comparison of mutagenic effects of common wheat by electron beam, fast neutron and 60Co gamma ray irradiation  

International Nuclear Information System (INIS)

After winter wheat was irradiated by electron beam, fast neutron and ?-rays, respectively, the RBE value of electron beam to both fast neutrons and ?-rays was less than one, the RBE value of fast neutron to ?-rays was largely more than one. This results indicated that biological effect of M1 generation induced by electron beam was less than that of fast neutrons very much, and similar to ?-ray irradiation. With electron beam irradiation, the half-lethal doses of M1 generation were from 185 to 370 Gy, closer to 370 Gy, the lethal doses from 740 to 925 Gy. M2 mutation efficiency with electron beam treatment was larger as compared with that with both fast neutrons and ?-rays. A wider mutation spectrum and higher mutation efficiency compared with other physical mutagens can be obtained with electron beam irradiation, about 30% higher than that with ?-ray irradiation. The best doses of irradiation with electron beam were 370 to 555 Gy. Fast neutrons, a better dose of which was 25 Gy, could induce more mutants than that with ?-rays in M2 generation. The dose in which biological injury reached to 50% was the best dose for M2 mutants by electron beam irradiation

1988-01-01

312

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

International Nuclear Information System (INIS)

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

1985-01-01

313

Experiment on gamma-ray generation and application  

Science.gov (United States)

An experimental setup of gamma-ray generation through laser Compton scattering has been built on the NewSUBARU storage ring. The aim is to study nuclear transmutation, which is regarded as the first stage to explore the feasibility of developing a nuclear waste disposal system based on the concept of irradiating long-lived fission products by laser Compton scattering gamma ray. In this paper, the gamma-ray generation facility is presented, and some experimental results such as gamma-ray energy spectrum, intensity distribution, and the coupling efficiency of nuclear transmutation, are given. The experimental data is in good agreement with the analytic calculation or simulation analysis.

Li, D.; Imasaki, K.; Aoki, M.; Miyamoto, S.; Amano, S.; Aoki, K.; Hosono, K.; Mochizuki, T.

2004-08-01

314

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

International Nuclear Information System (INIS)

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

2007-02-07

315

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

Science.gov (United States)

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.

Bekasova, O. D.; Revina, A. A.; Rusanov, A. L.; Kornienko, E. S.; Kurganov, B. I.

2013-11-01

316

Optical absorption in TlCl:Pb crystal induced with reactor and gamma-ray irradiation at low temperatures  

International Nuclear Information System (INIS)

TlCl crystals doped with Pb++ ions were irradiated in a reactor at low temperature and their absorption spectra were measured from 4.2 K to room temperature. Two prominent absorption bands were observed at 429 and 478 nm at 4.2 K which shifted to 426 and 465 nm at 77 K. They were quite similar to the bands which were observed in the undoped TlCl crystals irradiated in the reactor at low temperature. In the Pb-doped crystals more absorption bands were observed at 393 and 750 nm on warming to 77 K. The absorption of the undoped and Pb-doped crystals irradiated by Co60-? rays at 4.2 or 77 K were also measured and were compared with the results of the reactor-irradiated crystals. Only in the Pb-doped crystals ?-irradiated at 77 K, the 426 and 393 nm bands were observed with the intense 750 nm band. An interpretation of the effects of Pb++ ions on the creation of the defects in the crystal by irradiation is presented. (auth.)

1975-01-01

317

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

International Nuclear Information System (INIS)

Nitric oxide (NO) has been reported to be a radiosensitizer of mammalian cells under hypoxic conditions. In a previous study, we demonstrated an enhancement in radiation response induced by NO in mouse tumor cells under aerobic conditions, with an increasing effect as a function of malignancy. The aim of the present study was to evaluate the effect of NO in tumor cells and in experimental tumors irradiated with ? rays and proton beams. Irradiations were performed with a "1"3"7Cs ? source and with proton beams generated by the TANDAR accelerator. Tumor cells were treated with the NO donor DETA-NO and the sensitizer enhancement ratio (SER) was calculated using the ? parameter of the survival curve fitted to the linear-quadratic model. Tumor cells irradiated with protons were radio sensitized by DETA-NO only in the more malignant cells irradiated with low LET protons (2.69±0.08 keV/?m). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with ? rays, a significantly greater effect was demonstrated in the malignant cells (MCF-7) as compared with the near normal cells (HBL-100). Moreover, a significant decrease in tumor growth was demonstrated in mice pre-treated with the NO donor spermine and irradiated with ? rays and low LET protons as compared with mice irradiated without pre-treatment with the NO donor. In conclusion, we demonstrated a differential effect of NO as a radiosensitizer of malignant cells, both with ? rays and low LET protons. This selectivity, coupled to the in vivo inhibition of tumor growth, is of great interest for the potential use of NO releasing agents in radiotherapy. (author)

2003-11-26

318

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

319

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

Science.gov (United States)

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

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

2009-01-01

320

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

International Nuclear Information System (INIS)

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

2008-08-12

 
 
 
 
321

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

International Nuclear Information System (INIS)

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

1995-05-01

322

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

International Nuclear Information System (INIS)

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

2011-01-01

323

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

International Nuclear Information System (INIS)

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

1986-01-01

324

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

1995-10-01

325

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

International Nuclear Information System (INIS)

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

2002-01-01

326

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-06-01

327

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)

2008-01-01

328

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)

2004-02-01

329

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

330

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

Directory of Open Access Journals (Sweden)

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

TUR RAHARDJO

2013-09-01

331

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 irradiation

2003-08-01

332

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-08-01

333

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

Energy Technology Data Exchange (ETDEWEB)

'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 {sup 94G}Nb, whose half-life is as long as 20,300 years. Of course, {sup 94G}Nb is also produced by the decay of its short-lived isomer {sup 94m}Nb (T{sub 1/2} = 6.26 min). Hence, the amount of the radionuclide {sup 94G}Nb 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 {sup 94G}Nb (702 and 871 keV) and {sup 60G}Co (1173 and 1332 keV). The other radio-nuclides present in these samples include {sup 125}Sb, {sup 54}Mn, {sup 182}Ta, {sup 125m}Te, {sup 95}Nb and {sup 95}Zr. The absolute activities of all these radio-nuclides were determined from the peak areas of these spectra using the absolute detection efficiency of the detector determined with a standard {sup 152}Eu source. The spectral data was used to generate the axial profiles of the activities of the two radionuclides {sup 94G}Nb and {sup 60G}Co 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)

Newton Nathaniel, T.; Alur, Y.D. [Bhabha Atomic Research Centre, Mumbai (India); Ray, S. [Nuclear Power Corporation of India Limited, Nabhikiya Urja Bhavan, Anushaktinagar, Mumbai (India); Parikh, M.V. [Nuclear Power Corporation of India Limited, Kakhrapar Atomic Power Station, Kakhrapar, Gujarat (India); Ramadasan, E.; Reddy, A.V.R. [Bhabha Atomic Research Centre, Mumbai (India); Kumar, A.N. [Nuclear Power Corporation of India Limited, Nabhikiya Urja Bhavan, Anushaktinagar, Mumbai (India); Anantharaman, S. [Bhabha Atomic Research Centre, Mumbai (India)

2008-07-01

334

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

International Nuclear Information System (INIS)

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

2008-10-05

335

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

International Nuclear Information System (INIS)

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

1986-09-01

336

Thermoluminescence, thermoluminescence emission and optical absorption of CsI:Pb2+ crystals irradiated with gamma rays  

International Nuclear Information System (INIS)

Thermoluminescence, thermoluminescence emission and optical absorption studies have been made in lead doped cesium iodide crystal. Unirradiated crystal gives rise to optical absorption bands at 275, 230, 225 and 213 nm which are identified as the A,B,C,D, bands respectively of the lead impurity. The bands formed on irradiation at 382 nm and 331 nm are attributed to the Pb+ and Pb centres formed on irradiation. The TL glow curves show a peak at 383 K and a shoulder at 423 K. The peak at 383 K has emission at 330, 450 and 550* nm while the shoulder at 423 K has emission at 550 nm only. These peaks are attributed to Pb+ and Pb 0. (author). 15 refs., 5 figs

1993-01-01

337

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 [H_3N(CH_2)_3NH_2(CH_2)_4NH_3]"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 D_1_0 value at concentration of 10"-"5 M/L compared with the other two used concentrations of 10"-"6 and 10"-"4 M/L. Applying spermidine before irradiation was more effective than applying it after irradiation. (author)

2004-01-01

338

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)

2011-05-01

339

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-06-01

340

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

 
 
 
 
341

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

International Nuclear Information System (INIS)

Radioprotective effects of amifostine and melatonin on human peripheral blood irradiated with g-rays were investigated using the micronucleus (MN) assay and the analysis of sister chromatid exchanges (SCE). Duplicate blood samples were pre-treated with amifostine (7.7 mM), melatonin (2 mM) and their combination for 30 minutes. Negative controls were also included. After treatment with radioprotectors, one blood sample from each experimental group was exposed to g-rays from a 6"0"Co source. The radiation dose absorbed was 2 Gy. Pre-treated irradiated blood samples showed a decrease in the total number of MN and in the number of cells with more than one MN. Moreover, they also showed significantly lower mean SCE values. Our results indicate that amifostine, melatonin and their combination in vitro have radioprotective effects on g-irradiated human peripheral blood lymphocytes, with no significant genotoxicity. Therefore, it may be reasonable to use them in combination, adjusting the doses of amifostine to achieve the best radioprotective effect with as few side effects as possible. Before employment, this combination should be extensively tested in vitro and in vivo, using the same and other biomarkers for different radiation dose and concentration ranges of both radioprotectors.(author)

2005-04-18

342

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

International Nuclear Information System (INIS)

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

1988-01-01

343

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

International Nuclear Information System (INIS)

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

2009-10-02

344

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

Energy Technology Data Exchange (ETDEWEB)

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){sup -1} and 37.1 Gy min{sup -1}, respectively. The results concluded that tebo worms can resist more than 3 times the doses suggested by the meta countries without reducing the population drastically, nevertheless it is required to increase the number of worms to be analyzed in order to validate the findings. (author)

Silva R, Samy; Zarate S, Herman; Aguirre H, Paulina [Comision Chilena de Energia Nuclear, Santiago (Chile)], e-mail: hzarate@cchen.cl, e-mail: paguirre@cchen.cl, e-mail: ssilva@cchen.cl; Aburto, Patricio [Expo Agro (Chile)], e-mail: expoag@expoag.cl

2009-07-01

345

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

International Nuclear Information System (INIS)

This study deals with ionization of alkane-electron scavenger reactant mixtures, irradiated by 60Co ?-rays. It is shown that the extrapolated free-ion yields (extrapolated yield method) decrease with the reactant concentration. On the basis of ONSAGER model and theoretical treatment of MOZUMDER, the cross sections of epithermal electron attachment in hexane, cyclohexane, 2,2-dimethylbutane, cyclopentane, 2,2,4-trimethylpentane for CCl4, C7F14, C6H5Br, C6H5Cl, C6F14, (C6H5)2 are determined. A comparison between gas-phase and liquid-phase cross sections is established

1977-01-01

346

Gamma ray camera  

International Nuclear Information System (INIS)

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

1979-01-01

347

Gamma-Ray Astronomy  

Energy Technology Data Exchange (ETDEWEB)

Gamma-ray astronomy currently runs through an era of rapid progress and moving frontiers using satellite observatories up to photon energies of 10-to-100 GeV, and ground-based telescopes based on the imaging air-Cherenkov method. Such telescopes will soon be available for effective threshold energies above 10-to-50 GeV, therefore closing the last remaining gap in the coverage of the electromagnetic spectrum. Exploiting the non-thermal Universe,its relativistic particle content and the acceleration mechanisms operating in it, is a prime task of this field of research, but equally important is the potential of gamma-ray astronomy to probe the realm of heavy relic particles from the Early Universe, or to probe the propagation of energetic radiation across cosmological distances. (Author) 29 refs.

Mannheim, K.

2001-07-01

348

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

International Nuclear Information System (INIS)

Forty male Wistar rats in sexual maturity received gamma irradiation (0.5 Gy, 1.0 Gy, 2.0 Gy and 4.0 Gy; 1.26 Gy/min). The content of the TTH, T3 and T4 in the blood plasma was determined radioimmunologically on days 1, 2, 3, 6, 12, 20, 30 and 40 after the treatment. In 10 animals a normal level of these hormones was established. Their quantity varied as early as in the first days following the irradiation. The content of T3 and T4 increted by the thyroid gland was inhibited, while the TTH produced in the adenohypophysis considerably increased in the first 5-6 days. After day 6 and particulary after day 12 a hypothyroidism of central and peripherial origin occured, which was most prominent for TTH and T4, and to a lesser degree for T3. The changes in the hormone content depended on the radiation dose, the hypothyroidism being most expressed at the higher doses of 2.0 Gy and 4.0 Gy

1989-01-01

349

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

Directory of Open Access Journals (Sweden)

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

S. Fares

2012-07-01

350

Chemical changes in the chloroform-paraffin-dye system irradiated with "6"0Co gamma-rays, 2  

International Nuclear Information System (INIS)

Studies have been carried out on the amount of hydrogen chloride formed by the radiolysis of chloroform in a solid paraffin-chloroform-Methyl Yellow system, and the color changes from yellow to red and absorption energy observed. The amount of hydrogen chloride formed and the intensity of the red color were determined with a pH meter, a spectrophotometer, and a color/ color-difference meter. It was found that the color-difference meter had the most excellent spectral response and sensitivity for measurement of the irradiated sample, and that the color-difference, ?E, obtained by reflectometry increased proportionally with the increase in the radiation dose throughout a region of 100 -- 5000 R. When a solid sample composed of 1.0 kg paraffin (m.p. 62 -- 64"0C), 0.74 kg chloroform and 3.4 x 10"-"3 mol Methyl Yellow was subjected to 1000 R irradiation at 20"0C, 2.5 x 10"1"4 molecules of hydrogen chloride were formed in 1.0 g of the solid sample with the absorption energy of 5.9 x 10"1"6 eV, 3.2 x 10"1"6 eV of which contributed to chloroform as the absorption energy. (author)

1981-01-01

351

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

Energy Technology Data Exchange (ETDEWEB)

Twenty-four patients undergoing pelvic irradiation for gynecologic malignancies had /sup 14/C-lactose breath tests performed in the first and fifth weeks of their treatment. The /sup 14/C-lactose breath test was performed by administering 2 ..mu..Ci of /sup 14/C-lactose by mouth along with 50 g of lactose. Breath samples were collected in ethanolic hyamine 1, 2, and 3 hr later; the radioactivity of the trapped /sup 14/CO/sub 2/ was determined by liquid scintillation spectroscopy. In the first week of treatment the percentage of administered /sup 14/C excreted as /sup 14/CO/sub 2/ at 1, 2, and 3 hr was 1.7 +- 0.8% (mean +- SD), 4.5 +- 1.6%, and 5.8 +- 1.4%, respectively. In the fifth week of treatment the 1-hr, 2-hr, and 3-hr values were 1.2 +- 0.9%, 3.6 +- 2.0%, and 4.7 +- 1.9%, respectively. The difference between the first week and fifth week test results at 1, 2, and 3 hr was statistically significant (t = 2.64, p < 0.02), (t = 2.24, p < 0.05), (t = 2.95, p < 0.01). There was a negative correlation between the 1-hr /sup 14/C-lactose breath test results in the fifth week and the stool frequency at that time (r = -0.44, p < 0.05). Seven of 12 patients whose 1 hr /sup 14/C-lactose breath test results in the fifth week were below normal (<1.2%) had nausea at that time. The data suggest that in some patients, lactose malabsorption as a result of the effect of radiation on small intestinal function may be etiologically related to the symptoms of nausea and diarrhea which occur commonly in patients who are undergoing pelvic irradiation. In addition, the results suggest that lactose-containing foods should be restricted in some patients who are undergoing pelvic irradiation to prevent symptoms resulting from radiation-induced lactose intolerance.

Stryker, J.A.; Mortel, R.; Hepner, G.W.

1978-01-01

352

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

International Nuclear Information System (INIS)

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

2003-09-07

353

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

Science.gov (United States)

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

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

2004-09-01

354

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

Science.gov (United States)

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

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

2002-01-01

355

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

International Nuclear Information System (INIS)

The radiation-induced UV-vis spectrum of ?-terthiophene radical cation in solid is reported. The radical cation initiates an oligomerization in the CTA matrix producing permanently coloured conjugated polarons. The specific net absorbance at 465 nm is linearly related with dose up to 2x106Gy, for electrons and gamma irradiation. The decrease of the UV typical absorption (355 nm) and of four IR bands of ?-terthiophene is linear with dose, as well. Although sensitivity is influenced by dose rate, it turned out that a linear relationship holds between sensitivity and log dose rate, in the range from 2 to 105 Gy, min. These findings suggest a potential application of the system for dosimetric purposes over a wide range of dose and dose rate.

2002-01-01

356

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

International Nuclear Information System (INIS)

Recently, studies have documented various health benefits of some natural herbal extracts (NHE) such as Houttuynia cordata (H), Centella asiatica (C), Plantago asiatica (P), Morus alba L. (M), and Ulmus davidiana (U). The aim of the present study was to demonstrate the radiation effect on NF-kB activation of the NHE in the human mast cell line (HMC-1). The HMC-1 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) plus A23187. Both non-and irradiated NHE also significantly inhibited the PMA plus A23187-induced nuclear factor NF-kB activation and also suppressed the expression of activation of NF-kB. These results indicated that the NHE exerted a regulatory effect on inflammatory reactions mediated by mast cells

2009-12-01

357

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

CERN Document Server

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

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

2002-01-01

358

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1981-12-01

359

{gamma}-ray irradiation effect on hysteresis symmetry and data retention of Pt/SrBi{sub 2}Ta{sub 2}O{sub 9}/Pt thin-film capacitors  

Energy Technology Data Exchange (ETDEWEB)

The {gamma}-ray irradiation effect on hysteresis symmetry and data retention of Pt/SrBi{sub 2}Ta{sub 2}O{sub 9}/Pt ferroelectric thin-film capacitors has been investigated as a function of irradiation dose. A horizontal shift of polarization-voltage curves along the voltage axis, known as imprint, was observed after the polarized capacitors had been irradiated. The voltage shift increased with increasing irradiation dose and increasing remanent polarization written before irradiation. After irradiation, severe data loss was observed after these capacitors had been written to the state opposite to the one stored during irradiation. Possible functional failure due to such a data loss was discussed. (orig.)

Wu, D.; Li, A.D.; Ling, H.Q. [National Lab. of Solid State Microstructures and Material Science and Engineering, Nanjing Univ. (China); Yu, T.; Liu, Z.G.; Ming, N.B. [National Lab. of Solid State Microstructures and Department of Physics, Nanjing Univ. (China)

2001-08-01

360

Unidentified Gamma-Ray Sources: Hunting Gamma-Ray Blazars  

Energy Technology Data Exchange (ETDEWEB)

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of the unidentified {gamma}-ray sources (UGSs). Despite the large improvements of Fermi in the localization of {gamma}-ray sources with respect to the past {gamma}-ray missions, about one third of the Fermi-detected objects are still not associated to low energy counterparts. Recently, using the Wide-field Infrared Survey Explorer (WISE) survey, we discovered that blazars, the rarest class of Active Galactic Nuclei and the largest population of {gamma}-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Based on this result, we designed an association method for the {gamma}-ray sources to recognize if there is a blazar candidate within the positional uncertainty region of a generic {gamma}-ray source. With this new IR diagnostic tool, we searched for {gamma}-ray blazar candidates associated to the UGS sample of the second Fermi {gamma}-ray catalog (2FGL). We found that our method associates at least one {gamma}-ray blazar candidate as a counterpart each of 156 out of 313 UGSs analyzed. These new low-energy candidates have the same IR properties as the blazars associated to {gamma}-ray sources in the 2FGL catalog.

Massaro, F.; D' Abrusco, R.; Tosti, G.; Ajello, M.; Gasparrini, A.Paggi.D.

2012-04-02

 
 
 
 
361

Thermoluminescence (TL) Analysis and Fading Studies of Naturally Occurring Salt Irradiated by 500 mGy Gamma Rays  

Science.gov (United States)

The aim of the present study was to investigate the potential of the naturally occurring salt for the dosimetry purposes, using TL. The fine powder samples (20 mg) were irradiated by ?- rays from 500 mGy to 2500 mGy by using Theratron-780C Cobalt-60 source, however, this paper discusses about 500 mGy only. The TL glow curve peak parameters were studied by using Chen's peak shape equation. TL glow curves were compared with fitted curves using glow curve deconvolution (GCD) method by using Kitis expression. The kinetic parameter values (E, b and s) so calculated, are in good agreement with those available in literature. The calculated energy values were also verified by using various heating rate (VHR) method. ?2 test and figure of merit (FOM) calculation was done to accept the goodness of fit between the curves. Fading studies of the sample showed a good fitting between the curves. The analysis suggests that natural salt should be considered for dosimetry purposes.

Tiwari, Ramesh Chandra; Pau, Kham Suan

2011-10-01

362

Transformation of egg-white glass into partially crystallized glass induced by heat treatment and gamma-ray irradiation  

International Nuclear Information System (INIS)

Egg-white gel is easily transformed into transparent 'glass' by drying at ambient temperature, e.g., at 25degC for 140 min. The optical transmittance is increased from 2 to 25% accompanied with a decrease in the weight by more than 70%. Broad and intense IR absorption peaks observed at 3288-3308 and 1653-1657 cm-1 were respectively assigned to ?(NH) and ??(C=0) stretching modes in the amido (RCONH-) groups, and the ?(NH) bending mode was observed at 1521-1546 cm-1. Differential thermal analysis (DTA) study showed a distinct endothermic peak due to the glass transition, and the peak position was located at 36, 42, 58 and 69degC when the heating rates were 2, 5, 10 and 20degC min-1, respectively. Heat treatment of egg-white glass at 60degC or ?-ray irradiation resulted in partial crystallization, and the XRD patterns showed a few diffraction peaks superimposed on the halo peak due to the glassy phase. (author)

1994-01-01

363

Spectra of colony size of CHO-fibroblastoma irradiated with 60Co gamma rays after freeze and thaw cycles  

International Nuclear Information System (INIS)

The production of reproductive lethal cell lesions by freeze and thaw cycles has been studied by means of colony size spectrometry in tetraploid CHO-fibroblastoma protected with glycerine. The verification sensitivity of this method is compared with that of the colony formation test, the survival curve of cells and the relative multiplicity. 20 days after a freeze and thaw cycle only the spectrometry of the colony size and the survival curve of the cells and colonies suggest a cell lesion. After 44 days, changes as a consequence of reproductive lethal lesions can be detected only in the spectrum of the colony size. Survival curves of the colonies, survival curves of the cells and relative multiplicities determined on cell strains 44 days after a freeze and thaw cycle are not significatively different from the results of non-frozen control cells. The relation of the average cellular multiplicity after a freeze and thaw cycle to that of the nonfrozen control cells approaches the value of 1 with increased cultivation period after a freeze and thaw cycle. The reproductive lethal lesion after a freeze and thaw cycle is also decreasing with an increased cultivation period. Proliferation lesions by means of 60Co gamma irradiation have been influenced in dependence of the dose by 20 days of freeze and thaw lesions of a cell population. (orig.)

1975-05-01

364

Cellular response to low Gamma-ray doses  

International Nuclear Information System (INIS)

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

2002-09-11

365

Gamma-ray localization of terrestrial gamma-ray flashes.  

Science.gov (United States)

Terrestrial gamma-ray flashes (TGFs) are very short bursts of high-energy photons and electrons originating in Earth's atmosphere. We present here a localization study of TGFs carried out at gamma-ray energies above 20 MeV based on an innovative event selection method. We use the AGILE satellite Silicon Tracker data that for the first time have been correlated with TGFs detected by the AGILE Mini-Calorimeter. We detect 8 TGFs with gamma-ray photons of energies above 20 MeV localized by the AGILE gamma-ray imager with an accuracy of ?5-10° at 50 MeV. Remarkably, all TGF-associated gamma rays are compatible with a terrestrial production site closer to the subsatellite point than 400 km. Considering that our gamma rays reach the AGILE satellite at 540 km altitude with limited scattering or attenuation, our measurements provide the first precise direct localization of TGFs from space. PMID:20867680

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

2010-09-17

366

Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes  

International Nuclear Information System (INIS)

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

2010-09-17

367

Gamma-Ray Localization of Terrestrial Gamma-Ray Flashes  

CERN Document Server

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

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

2010-01-01

368

Thermal properties of irradiated ethylene-propylene copolymers  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-07-15

369

Thermal properties of irradiated ethylene-propylene copolymers  

International Nuclear Information System (INIS)

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

1996-07-15

370

Neutron/gamma ray source measurement and analyses of high burnup UO2/MOX fuel rods  

International Nuclear Information System (INIS)

Axial directional neutron and gamma ray source measurement of fuel rods and radial directional gamma ray source measurement of fuel pellets were carried out for LWR high burn-up UO2 and MOX spent fuels. C/E values with ORIGEN-2 code are discussed for axial neutron and gamma ray source distributions of fuel rods. The radial gamma ray source distribution of a fuel pellet shows Cs migration/vaporization phenomena during irradiation. Using the radial gamma ray source distribution data of Cs-134 and Cs-137, the Cs migration/vaporization time during irradiation can be estimated. (author)

2000-03-01

371

Effect of gamma-ray irradiation on in-situ electrical conductivity of ZrO_2-10 mol% Gd_2O_3 single crystal at elevated temperatures  

International Nuclear Information System (INIS)

Change of electrical conductivity with irradiation of "6"0Co gamma rays was investigated on ZrO_2-10 mol% Gd_2O_3 single crystal at 623, 723, and 823 K in vacuum. Conductivity increased gradually with irradiation time, while activation energy remained invariant. The increment of in-situ conductivity was attributed to the creation of oxygen vacancies introduced by the formation of Frenkel defects that were produced by the bombardments of Compton electrons. These increased oxygen vacancies were responsible for the radiation induced electrical conducitivity (RIC) of the material and their contribution to RIC continued until they recombine with oxygen interstitials. (orig.)

1994-05-01

372

Surface treatment of poly(ethylene terephthalate) by gamma-ray induced graft copolymerization of methyl acrylate and its toughening effect on poly(ethylene terephthalate)/elastomer blend  

Science.gov (United States)

To improve the compatibility between ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (E-MA-GMA) elastomer and poly(ethylene terephthalate) (PET), thereby enhance the toughening effect of E-MA-GMA on PET, ?-radiation-induced graft copolymerization technique was used to graft methyl acrylate (MA) monomer onto PET. The produced PET-g-PMA copolymer can be used as a self-compatibilizer in PET/E-MA-GMA blend since the copolymer contains the same segments, respectively, with PET and E-MA-GMA. The impact strength of PET/E-MA-GMA blend increased nearly by 30% in the presence of less than 0.1 wt% PET-g-PMA compared with that of the neat PET/elastomer blend, without loss of the tensile strength of the blends. This work proposed a potential application of radiation-induced grafting copolymerization technique on the in-situ compatibilization of PET/elastomer blends so as to improve the integral mechanical properties of PET based engineering plastic.

Ma, Liang; Wang, Mozhen; Ge, Xuewu

2013-09-01

373

Secondary gamma-ray measurements  

International Nuclear Information System (INIS)

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

2004-07-01

374

Unidentifed gamma-ray sources: hunting gamma-ray blazars  

CERN Document Server

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of the unidentified gamma-ray sources (UGSs). Despite the large improvements of Fermi in the localization of gamma-ray sources with respect to the past gamma-ray missions, about one third of the Fermi-detected objects are still not associated to low energy counterparts. Recently, using the Wide-Field Infrared Survey Explorer (WISE) survey, we discovered that blazars, the rarest class of Active Galactic Nuclei and the largest population of gamma-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Based on this result, we designed an association method for the gamma-ray sources to reognize if there is a blazar candidate within the positional uncertainty region of a generic gamma-ray source. With this new IR diagnostic tool, we searched for gamma-ray blazar candidates associated to the UGS sample of the second Fermi gamma-ray catalog (2FGL). We found tha...

Massaro, F; Tosti, G; Ajello, M; Gasparrini, A Paggi D

2012-01-01

375

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

International Nuclear Information System (INIS)

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

1982-09-27

376

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

International Nuclear Information System (INIS)

Polyurethane elastomers (PUEs) based on 4,4'-diphenylmethane diisocyanate (MDI), poly (?-caprolactone) (PCL) and extended with series of chain extender (CE) were synthesized via two step polymerization technique. The synthesized samples were irradiated for 50, 100 and 200 h in an UV exposure unit as such the spectral distribution of the light is good match for terrestrial solar radiation. The modifications in the chemical structures of the PU before and after irradiation were characterized using Fourier transform infrared (FT-IR) technique. The effect of irradiation time and chain extenders length on surface properties were studied and investigated. Photo-oxidation of PU surface leads to fast increase in surface free energy and its polar component. Simultaneously, the work of water adhesion to polymer increases significantly during UV-irradiation. The higher changes in surface properties, observed by water absorption (%), equilibrium degree of swelling, as well as monitored by ATR-FT-IR and contact angle measurement, were found for the PU samples extended with higher number of methylene unit and irradiation time

2008-08-30

377

Digital Pulse Processing and Gamma Ray Tracking  

Science.gov (United States)

Two of the big changes in new generations of Nuclear Physics instrumentation will be the incorporation of digital processing and the use of gamma ray tracking. The Nuclear Physics Group at Daresbury has set up a project to investigate digital pulse processing for gamma ray detectors and how best to implement gamma ray tracking in large Germanium gamma ray detectors. Topics on this site include but are not limited to: gamma ray tracking, overview of the Gamma Ray Tracking Project, pictures of one of the tracking gamma ray detectors (TIGRE), pictures of test experiment, gamma ray tracking project publications, and links to other gamma ray tracking pages.

2010-09-21

378

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

International Nuclear Information System (INIS)

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

1952-01-01

379

Experiment on iodine transmutation by laser Compton scattering gamma ray  

Science.gov (United States)

A laser Compton scattering gamma-ray based nuclear transmutation is proposed to reduce the hazards of long-lived activity nuclear waste. In accordance with this proposal, a laser Compton scattering gamma-ray facility has been built on NewSUABARU storage ring. The facility provides 17.6 MeV gamma-ray photons, which is applicable to the nuclear transmutation research. In order to investigate the reaction rate of Iodine material, the 23Na127I target is adopted for the irradiation experiment. The results show that the experimental data is close to the simulation result.

Li, D.; Imasaki, K.; Miyamoto, S.; Horikawa, K.; Amano, S.; Mochizuki, T.

2008-05-01

380

Experiment on iodine transmutation by laser Compton scattering gamma ray  

Energy Technology Data Exchange (ETDEWEB)

A laser Compton scattering gamma-ray based nuclear transmutation is proposed to reduce the hazards of long-lived activity nuclear waste. In accordance with this proposal, a laser Compton scattering gamma-ray facility has been built on NewSUABARU storage ring. The facility provides 17.6 MeV gamma-ray photons, which is applicable to the nuclear transmutation research. In order to investigate the reaction rate of Iodine material, the {sup 23}Na{sup 127}I target is adopted for the irradiation experiment. The results show that the experimental data is close to the simulation result.

Li, D; Imasaki, K [Institute for Laser Technology, 2-6 yamadaoka suita, Osaka (Japan); Miyamoto, S; Horikawa, K; Amano, S; Mochizuki, T [LASTI, University of Hyogo, 3-1-2 koto, kamigori, ako, Hyogo (Japan)], E-mail: dazhi_li@hotmail.com

2008-05-01