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1

Level Density and Radiative Strength Functions of Dipole gamma-Transitions in 163Dy  

E-print Network

Using our early experimental data on the cascade gamma-transitions from the 162Dy(n,2gamma) reaction, we determined dependence of the cascade intensity on the energy of their intermediate levels, and then - level density and radiatibe strength functions which allow precise reproduction of the experimental two-step cascade intensities and total gamma-width. Level density in this nucleus (like in other earlier studied even-odd nuclei) in the interval 1 to 3 MeV is considerably less than that predicted by Fermi-gas model. Enhancement of the radiative strength functions, caused by strong correlations of parameters, most probably, relates with the change in ratio between the quasi-particle and collective component of the wave functions of the cascade intermediate levels in the region of most strong change in their density.

V. A. Khitrov; Li Chol; A. M. Sukhovoj

2005-08-08

2

Level Density and Radiative Strength functions of Dipole gamma-Transitions in Ba-139 and Dy-165  

E-print Network

Level density and radiative strength functions which allow precise reproduction of the two-step cascade intensity, gamma width of compound state and cascade population of levels up to excitation energy of about 3.5 MeV were determined using experimental data on the (n,2gamma) reaction. Level density in these nuclei (like in other even-odd nuclei studied earlier) in wide excitation energy interval is considerably less than that predicted by Fermi-gas model. Enhancement of the radiative strength functions, caused by strong correlations between cascade gamma-decay parameters, most probably, relates with the change in ratio between the quasi-particle and collective components of the wave functions of the cascade intermediate levels in the region of most strong change in their density.

V. A. Khitrov; A. M. Sukhovoj; Pham Dinh Khang; Vuong Huu Tan; Nguyen Xuan Hai

2005-08-05

3

Effect of gamma radiation on the ripening and levels of bioactive amines in bananas cv. Prata  

NASA Astrophysics Data System (ADS)

Green Prata bananas at the full three-quarter stage were exposed to gamma radiation at doses of 0.0 (control), 1.0, 1.5 and 2.0 kGy and stored at 16±1 °C and 85% relative humidity. Samples were collected periodically and analyzed for peel color, pulp-to-peel ratio and levels of starch, soluble sugars and bioactive amines. Degradation of starch and formation of fructose and glucose followed first- and zero-order kinetics, respectively. Higher irradiation doses caused increased inhibitory effect on starch degradation and glucose formation. However, doses of 1.5 and 2.0 kGy caused browning of the peel, making the fruit unacceptable. Irradiation at 1.0 kGy was the most promising dose: it did not affect peel color, the pulp-to-peel ratio or the levels of the amines spermidine, serotonin and putrescine. However, it slowed down starch degradation and the formation and accumulation of fructose and glucose, delaying the ripening of the fruit for 7 days.

Gloria, Maria Beatriz A.; Adão, Regina C.

2013-06-01

4

Does short-term exposure to elevated levels of natural gamma radiation in Ramsar cause oxidative stress?  

PubMed Central

Background: Ramsar, a city in northern Iran, has areas with some of the highest recorded levels of natural radiation among inhabited areas measured on the earth. Aims: To determine whether short-term exposure to extremely high levels of natural radiation induce oxidative stress. Materials and Methods: In this study, 53 Wistar rats were randomly divided into five groups of 10-12 animals. Animals in the 1st group were kept for 7 days in an outdoor area with normal background radiation while the 2nd , 3rd , 4th and 5th groups were kept in four different outdoor areas with naturally elevated levels of gamma radiation in Ramsar. A calibrated RDS-110 survey meter, mounted on a tripod approximately 1 m above the ground, was used to measure exposure rate at each location. On days 7 and 9 blood sampling was performed to assess the serum levels of catalase (CAT) and malondialdehyde (MDA). On day 8, all animals were exposed to a lethal dose of 8 Gy gamma radiations emitted by a Theratron Phoenix (Theratronics, Canada) Cobalt-60 (55 cGy/min) at Radiotherapy Department of Razi Hospital in Rasht, Iran. Results: Findings obtained in this study indicate that high levels of natural radiation cannot induce oxidative stress. CAT and MDA levels in almost all groups were not significantly different (P = 0.69 and P = 0.05, respectively). After exposure to the lethal dose, CAT and MDA levels in all groups were not significantly different (P = 0.054 and P = 0.163, respectively). Conclusions: These findings indicate that short-term exposure to extremely high levels of natural radiation (up to 196 times higher than the normal background) does not induce oxidative stress. PMID:25143879

Mortazavi, SMJ; Niroomand-Rad, A; Roshan-Shomal, P; Razavi-Toosi, SMT; Mossayeb-Zadeh, M; Moghadam, M

2014-01-01

5

Outdoor 220Rn, 222Rn and terrestrial gamma radiation levels: investigation study in the thorium rich Fen Complex, Norway.  

PubMed

The present study was done in the Fen Complex, a Norwegian area rich in naturally occurring radionuclides, especially in thorium ((232)Th). Measurement of radioactivity levels was conducted at the decommissioned iron (Fe) and niobium (Nb) mining sites (TENORM) as well as at the undisturbed wooded sites (NORM), all open for free public access. The soil activity concentrations of (232)Th (3280-8395 Bq kg(-1)) were significantly higher than the world and the Norwegian average values and exceeded the Norwegian screening level (1000 Bq kg(-1)) for radioactive waste, while radium ((226)Ra) was present at slightly elevated levels (89-171 Bq kg(-1)). Terrestrial gamma dose rates were also elevated, ranging 2.6-4.4 ?Gy h(-1). Based on long-term surveys, the air concentrations of thoron ((220)Rn) and radon ((222)Rn) reached 1786 and 82 Bq m(-3), respectively. Seasonal variation in the outdoor gamma dose rates and Rn concentrations was confirmed. Correlation analyses showed a linear relationship between air radiation levels and the abundance of (232)Th in soil. The annual outdoor effective radiation doses for humans (occupancy 5 h day(-1)) were estimated to be in the range of 3.0-7.7 mSv, comparable or higher than the total average (summarized indoor and outdoor) exposure dose for the Norwegian population (2.9 mSv year(-1)). On the basis of all obtained results, this Norwegian area should be considered as enhanced natural radiation area (ENRA). PMID:22105600

Mrdakovic Popic, Jelena; Bhatt, Chhavi Raj; Salbu, Brit; Skipperud, Lindis

2012-01-01

6

Gamma radiation field intensity meter  

DOEpatents

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

Thacker, L.H.

1994-08-16

7

Gamma radiation field intensity meter  

DOEpatents

A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

Thacker, L.H.

1995-10-17

8

Estimation of Low-Level Radiation Dose from Some Building Materials Using Gamma Spectroscopy  

Microsoft Academic Search

The study of the radiation hazards from building materials is of interest in many countries. So, it becomes necessary to study the natural radioactivity in different materials to assess the dose for the population to know the health risks and to have a baseline for future changes in the environmental radioactivity due to human activities. The present study assesses the

Monika Gupta; R. P. Chauhan

2012-01-01

9

Unraveling low-level gamma radiation--responsive changes in expression of early and late genes in leaves of rice seedlings at litate Village, Fukushima.  

PubMed

In the summer of 2012, 1 year after the nuclear accident in March 2011 at the Fukushima Daiichi nuclear power plant, we examined the effects of gamma radiation on rice at a highly contaminated field of Iitate village in Fukushima, Japan. We investigated the morphological and molecular changes on healthy rice seedlings exposed to continuous low-dose gamma radiation up to 4 µSv h(-1), about 80 times higher than natural background level. After exposure to gamma rays, expression profiles of selected genes involved in DNA replication/repair, oxidative stress, photosynthesis, and defense/stress functions were examined by RT-PCR, which revealed their differential expression in leaves in a time-dependent manner over 3 days (6, 12, 24, 48, and 72 h). For example, OsPCNA mRNA rapidly increased at 6, 12, and 24 h, suggesting that rice cells responded to radiation stress by activating a gene involved in DNA repair mechanisms. At 72 h, genes related to the phenylpropanoid pathway (OsPAL2) and cell death (OsPR1oa) were strongly induced, indicating activation of defense/stress responses. We next profiled the transcriptome using a customized rice whole-genome 4×44K DNA microarray at early (6h) and late (72 h) time periods. Low-level gamma radiation differentially regulated rice leaf gene expression (induced 4481 and suppressed 3740 at 6 h and induced 2291 and suppressed 1474 genes at 72 h) by at least 2-fold. Using the highly upregulated and downregulated gene list, MapMan bioinformatics tool generated diagrams of early and late pathways operating in cells responding to gamma ray exposure. An inventory of a large number of gamma radiation-responsive genes provides new information on novel regulatory processes in rice. PMID:25124817

Hayashi, Gohei; Shibato, Junko; Imanaka, Tetsuji; Cho, Kyoungwon; Kubo, Akihiro; Kikuchi, Shoshi; Satoh, Kouji; Kimura, Shinzo; Ozawa, Shoji; Fukutani, Satoshi; Endo, Satoru; Ichikawa, Katsuki; Agrawal, Ganesh Kumar; Shioda, Seiji; Fukumoto, Manabu; Rakwal, Randeep

2014-01-01

10

Gamma radiation from radio pulsars  

NASA Technical Reports Server (NTRS)

The probable magnetospheric location and source of the gamma ray emission from some young radiopulsars is discussed. The suggested evolution of this emission as a function of pulsar period gives a diminished gamma-ray luminosity for a more rapidly spinning pre-Crab pulsar. A greatly enhanced one, similar to that of unidentified Cos B sources, is predicted for a slightly slower post-Vela pulsar, followed by a relatively rapid quenching of the gamma-ray luminosity at still longer periods. Possible anomalous exo-magnetospheric pulsed MeV and TeV-PeV radiation from the Crab pulsar is considered.

Ruderman, Malvin

1990-01-01

11

Radiation effect on PMMA POF under gamma-ray irradiation  

Microsoft Academic Search

An irradiation test was performed for polymethylmethacrylate plastic optical fibers under gamma-ray irradiation in order to use the fiber in low-level radiation environments. Under gamma-ray irradiation at a high dose rate, only a large radiation-induced transmission loss at wavelengths less than 700 nm was observed. Under irradiation at a low dose rate, the loss was small and other two characteristic

K. Toh; S. Nagata; B. Tsuchiya; T. Shikama

2007-01-01

12

Apparatus and method for detecting gamma radiation  

DOEpatents

A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

Sigg, R.A.

1994-12-13

13

Apparatus and method for detecting gamma radiation  

DOEpatents

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

Sigg, Raymond A. (Martinez, GA)

1994-01-01

14

Comparative study of the gamma-radiation-induced changes in the tissular levels of acyclic and cyclic adenosine phosphates.  

PubMed

Periodical measurement of total adenosine phosphates and cAMP in liver, intestinal mucosa and brain carried out in rats after irradiation with either 500 rads or 750 rads generally revealed high intratissular levels of these compounds, suggesting both a stimulated cellular synthesis and an abnormal redistribution in different tissues. The most interesting findings were those regarding the brain considering their close relationships with the clinical evolution of the animals and other previously described biochemical observations. PMID:181768

P?u?escu, E; Popescu, M; Teodosiu, T; Dinescu, I

1976-01-01

15

Spatial distribution of gamma radiation levels in surface soils from Jaduguda uranium mineralization zone, Jharkhand, India, using ?-ray spectrometry, and determination of outdoor dose to the population  

PubMed Central

The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of 238U, 232Th, and 40K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of 238U, 232Th, and 40K in the surface soil were 53.8, 44.2 and 464.2 Bq kg?1 respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides towards dose rate. The radio-elemental concentrations of uranium, thorium and potassium estimated for the soils, in the study area, indicated the enrichment of uranium series nuclide. The results of the present study were subsequently compared with international and national recommended values. PMID:21170189

Maharana, Mandakini; Krishnan, Narayani; Sengupta, D.

2010-01-01

16

Annual effective dose from environmental gamma radiation in Bushehr city  

PubMed Central

Background Present study was an attempt to measure outdoor and indoor gamma dose rates in Bushehr city to determine corresponding annual effective dose and, to assess effect of active nuclear power plant located in Bushehr city on background radiation level of this city. Methods All measurements were performed by G.M (Geiger Muller) detector (X5C plus) calibrated in Iran Atomic Energy Agency. In order to avoid effects of ground on outdoor and indoor measurements, G.M detector was placed one meter higher than ground level. Also, during the outdoor measurements, G.M detector was used at least six meters away from the walls of any building nearby to avoid unwanted effects of the materials used in the buildings on measurements. Results Average gamma dose rates of outdoor and indoor measurements were determined as 51.8?±?8.8 nSv/h and 60.2?±?7.2 nSv/h, respectively. Annual effective dose due to background gamma radiation was calculated as 0.36 mSv which was lower than average global level. Conclusions The average annual effective dose from background gamma radiation in Bushehr city was less than global level. Comparison of the results of present study, as follow up, with previous attempt performed in 2004 to determine effective dose of environmental gamma radiation in Bushehr province revealed that, during eight years, nuclear power plant located in this city has not significantly increased level of annual effective dose of Bushehr city. PMID:24393421

2014-01-01

17

Gamma -radiations connected to atmospheric precipitations  

NASA Astrophysics Data System (ADS)

Since 2008 we are monitoring the gamma -radiation in surface layer of atmosphere with scin-tillation gamma -spectrometers. Instruments consist of a crystal NaI (Tl), a photomultiplier and a pulse amplifier. The data are transmitted to a computer with a special card with the 4096 channel pulse-amplitude analyzer. The gamma-ray monitoring is presently carried out at two high-latitude points: Apatity (N 65.57, E 33.39) and Barentsburg, Spitsbergen(N 78.06, E 14.22). The detectors in Apatity and Barentsburg are covered from sides and bottom by metallic screen for shielding them from environmental radiations from a building and ground. Together with gamma-spectrometer in Apatity a precipitation measuring device (PMD) was installed, which allows us to estimate presence and intensity of precipitations. Information about precipitations in Barentsburg was taken from the local meteorological observatory. The observations have shown that sporadic increases of gamma -radiation registered by spectrome-ters are almost always accompanied by intensive precipitations (rain, snowfall). The measured spectrum of gamma -radiation was rather smooth and did not show peaks in a range from 1 up to 200 KeV. Two basic hypotheses of an origin of high-energy photons during precipitations are discussed. The first is probable connection with atmospheric radionuclides, which are at-tached to aerosols and are taken out from the atmosphere by precipitations (rain and snow). Against this hypothesis speaks lack of peaks on gamma-ray spectrum. The gamma-spectrum from radionuclides usually has characteristic and expressed spectral lines. The second probable cause is x-ray radiation arising at deceleration in air of free electrons, accelerated in an electric field between clouds and ground. All cases of precipitations are accompanied by dense cloudi-ness and strengthening of an atmospheric electric field. The arguments for this mechanism are resulted.

Vashenyuk, Eduard; Balabin, Yury; Gvozdevsky, Boris; Germanenko, Alexey

18

Low-Level Gamma Ray Detection in Humans  

Microsoft Academic Search

The problem of measuring gamma activity at the natural levels, particularly in people and foodstuffs, is an extremely important one because of the necessity of monitoring both fallout from nuclear weapons tests and the disposal of reactor wastes. This problem will also be encountered because of the necessity for minimizing radiation in clinical and industrial tracer applications. Two principal techniques

E. C. Anderson; M. A. Van Dilla

1958-01-01

19

Mortality of Mallards Exposed to Gamma Radiation Author(s): Richard L. Abraham  

E-print Network

for one-year-old mallards(Anas platyrhynchos)of 650 R for x-radiation and 630 R for 60-Co, Gamma radiation) mallard ducks (Anas platyrhynchos).Birds were exposed to whole- body gamma irradiationfrom a cesium-137)levels of 485 R, 715 R, and 894 R have been determined for green- winged teal (Anas crecca),blue-winged teal

Minnesota, University of

20

Effects of alpha, gamma, and alpha-recoil radiation on borosilicate glass containing Savannah River Plant defense high-level nuclear waste. [Lead ions-250 keV; xenon ions-160 keV  

SciTech Connect

At the Savannah River Plant, the reference process for the immobilization of defense high-level waste (DHLW) for geologic storage is vitrification into borosilicate glass. During geologic storage for 10/sup 6/ y, the glass would be exposed to approx. 3 x 10/sup 10/ rad of ..beta.. radiation, approx. 10/sup 10/ rad of ..gamma.. radiation, and 10/sup 18/ particles/g glass for both ..cap alpha.. and ..cap alpha..-recoil radiation. This paper discusses tests of the effect of these radiations on the leachability and density of the glass. Even though the doses were large, no effect of the radiations was detected that reduced the effectiveness of the glass for long-term storage of DHLW even at doses corresponding to 10/sup 6/ years storage for the actual glass. For the tests, glass containing simulated DHLW was prepared from frit of the reference composition. Three methods were used to irradiate the glass: external irradiations with beams of approx. 200 keV Xe or Pb ions, internal irradiations with Cm-244 doped glass, and external irradiations with Co-60 ..gamma.. rays. Results with both Xe and Pb ions indicate that a dose of 3 x 10/sup 13/ ions/cm/sup 2/ (simulating > 10/sup 6/ years storage) does not significantly increase the leachability of the glass in deionized water. Tests with Cm-244 doped glass show no increase in leach rate in water or brine up to a dose of 10/sup 18/ ..cap alpha.. and ..cap alpha..-recoils/g glass. Results of larger doses are being examined. The density of the Cm-244 doped glass has decreased by 1% at a dose of 10/sup 18/ particles/g glass. With ..gamma..-radiation, the density has changed by < 0.05% at a dose of 8.5 x 10/sup 10/ rad. Results of leach tests in deionized water and brine indicated that this very large dose of ..gamma..-radiation increased the leach rate by only 20%. Also, the leach rates are lower in brine.

Bibler, N.E.

1981-01-01

21

Composition and apparatus for detecting gamma radiation  

DOEpatents

A gamma radiation detector and a radioluminiscent composition for use therein. The detector includes a radioluminscent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO.sub.4) or cerussite (PbCO.sub.3) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes.

Hofstetter, Kenneth J. (Aiken, SC)

1994-01-01

22

30 CFR 57.5047 - Gamma radiation surveys.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Gamma radiation surveys. 57.5047 Section 57...METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047...

2011-07-01

23

30 CFR 57.5047 - Gamma radiation surveys.  

...2014-07-01 2014-07-01 false Gamma radiation surveys. 57.5047 Section 57...METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047...

2014-07-01

24

30 CFR 57.5047 - Gamma radiation surveys.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Gamma radiation surveys. 57.5047 Section 57...METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047...

2013-07-01

25

30 CFR 57.5047 - Gamma radiation surveys.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Gamma radiation surveys. 57.5047 Section 57...METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047...

2010-07-01

26

30 CFR 57.5047 - Gamma radiation surveys.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Gamma radiation surveys. 57.5047 Section 57...METAL AND NONMETAL MINES Air Quality, Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047...

2012-07-01

27

Variations of gamma radiation spectra during precipitations  

NASA Astrophysics Data System (ADS)

In the present paper results of prolonging studies of variations of a natural gamma (X-ray) radiation during precipitations registered at cosmic ray station in Apatity are presented. To the present time in the complex installation realizing monitoring of the near ground radiation, the detector is added on the basis of a scintillation crystal by size Ø150×100 mm. The special procedure of working out of the differential energy spectra obtained on the basis of this detector is designed. Due to this it is found, that increases are produced by an additional flux of radiation with the non-regular descending energy spectrum superimposed on a background radiation, having a power law energy spectrum. The clear upper energy limit of the additional radiation, accompanying with precipitations, is observed. It is 1.8-2.0 MeV. Any spectral lines, which could be produced by radionuclides, are not revealed in all researched gamut. It is concluded that these fluxes are produced by energetic charged particles during their passage through the atmosphere, i.e. Bremsstrahlung generation process. Based on the energy balance, the minimum field strength, which can cause a secondary increase, was performed.

Balabin, Yu V.; Germanenko, A. V.; Gvozdevsky, B. B.; Vashenyuk, E. V.

2013-02-01

28

Gamma radiation from the Crab and Vela pulsars  

NASA Technical Reports Server (NTRS)

The young pulsars in Crab and Vela were observed as very efficient emitters of high energy gamma radiation. While their radiation in the radio, optical, and x ray range was always known to differ considerably, the gamma ray emission on a superficial level appears quite similar: lightcurves with two narrow peaks, separated by 141 deg (Crab) and 153 deg (Vela) and photon energies in excess of 1 GeV with spectra that can be described by a power-law for Crab and a broken power-law for Vela. The detailed observations of these sources with the COS-B instrument, extending over nearly seven years, have revealed significant differences in the characteristics of the pulsars in the gamma-ray domain. Secular changes in the temporal (Crab) and spectral (Vela) properties above 50 MeV were found. These tantalizing signatures of the pulsar emission processes must now be explored in more detail and over a larger spectral range with the GRO (Gamma Ray Observatory) instruments in order to gain a deeper understanding of the physics of young neutron stars.

Kanbach, Gottfried

1990-01-01

29

Optical Sensors for Monitoring Gamma and Neutron Radiation  

NASA Technical Reports Server (NTRS)

For safety and efficiency, nuclear reactors must be carefully monitored to provide feedback that enables the fission rate to be held at a constant target level via adjustments in the position of neutron-absorbing rods and moderating coolant flow rates. For automated reactor control, the monitoring system should provide calibrated analog or digital output. The sensors must survive and produce reliable output with minimal drift for at least one to two years, for replacement only during refueling. Small sensor size is preferred to enable more sensors to be placed in the core for more detailed characterization of the local fission rate and fuel consumption, since local deviations from the norm tend to amplify themselves. Currently, reactors are monitored by local power range meters (LPRMs) based on the neutron flux or gamma thermometers based on the gamma flux. LPRMs tend to be bulky, while gamma thermometers are subject to unwanted drift. Both electronic reactor sensors are plagued by electrical noise induced by ionizing radiation near the reactor core. A fiber optic sensor system was developed that is capable of tracking thermal neutron fluence and gamma flux in order to monitor nuclear reactor fission rates. The system provides near-real-time feedback from small- profile probes that are not sensitive to electromagnetic noise. The key novel feature is the practical design of fiber optic radiation sensors. The use of an actinoid element to monitor neutron flux in fiber optic EFPI (extrinsic Fabry-Perot interferometric) sensors is a new use of material. The materials and structure used in the sensor construction can be adjusted to result in a sensor that is sensitive to just thermal, gamma, or neutron stimulus, or any combination of the three. The tested design showed low sensitivity to thermal and gamma stimuli and high sensitivity to neutrons, with a fast response time.

Boyd, Clark D.

2011-01-01

30

On the omnipresent background gamma radiation of the continuous spectrum  

NASA Astrophysics Data System (ADS)

The background spectrum of a germanium detector, shielded from the radiations arriving from the lower and open for the radiations arriving from the upper hemisphere, is studied by means of absorption measurements, both in a ground level and in an underground laboratory. The low-energy continuous portion of this background spectrum that peaks at around 100 keV, which is its most intense component, is found to be of very similar shape at the two locations. It is established that it is mostly due to the radiations of the real continuous spectrum, which is quite similar to the instrumental one. The intensity of this radiation is in our cases estimated to about 8000 photons/(m2s·2?·srad) in the ground level laboratory, and to about 5000 photons/(m2s·2?·srad) in the underground laboratory, at the depth of 25 m.w.e. Simulations by GEANT4 and CORSIKA demonstrate that this radiation is predominantly of terrestrial origin, due to environmental gamma radiations scattered off the materials that surround the detector (the "skyshine radiation"), and to a far less extent to cosmic rays of degraded energy.

Banjanac, R.; Maleti?, D.; Jokovi?, D.; Veselinovi?, N.; Dragi?, A.; Udovi?i?, V.; Ani?in, I.

2014-05-01

31

Gamma radiation effects on nestling Tree Swallows  

SciTech Connect

The sensitivity of Tree Swallows (Tachycineta bicolor) to the stress of ionizing radiation was investigated with growth analysis. Freshly hatched nestlings were temporarily removed from nests, taken to the laboratory and acutely exposed to 0.9, 2.7, or 4.5 Gy gamma radiation. Some of the unirradiated control nestlings were also taken to the laboratory whereas others were left in the nests. Growth of all the nestlings was measured daily and analyzed by fitting growth models. There was no detectable radiation-induced mortality up to fledgling, approx. = 20 d after irradiation. Radiation exposure did not affect the basic growth pattern; the logistic growth model was most suitable for body mass and foot length, and the von Bertalanffy model for primary-feather length, irrespective of treatment. Parameter values from these models indicated pronounced growth depression in the 2.7-Gy and 4.5-Gy groups, particularly for body mass. Radiation also affected the timing of development. The growth depression of the 2.7-Gy group was similar to that caused by hatching asynchrony in unirradiated nestlings. The 4.5-Cy nestlings grew as well as unexposed nestlings that died from natural causes. Chronic irradiation at approx. = 1.0 Cy/d caused more severe growth effects than acute exposure to 4.5 Gy and may have caused permanent stunting. Growth analysis is a potent tool for assessing man-made environmental stresses. Observed body-mass statistics and model parameters seem to be most sensitive to environmental stresses, but coefficients of variation are not necessarily correlated with sensitivity. 34 references, 2 figures, 4 tables.

Zach, R.; Mayoh, K.R.

1984-10-01

32

Immobilization of stationary phases onto chromatographic supports by gamma radiation  

Microsoft Academic Search

Cobalt-60 gamma radiation has been found to be an effective means of immobilizing stationary phases onto gas and liquid chromatographic supports. The ability of a phase to crosslink was determined to be highly dependent on its chemical structure. Gamma radiation was employed to immobilize Se-30, a methylsilicone, and 216 PS onto Chromosorb WHP for packed column chromatography. The resultant columns

Lyons

1987-01-01

33

Orchid flowers tolerance to gamma-radiation  

NASA Astrophysics Data System (ADS)

Cut flowers are fresh goods that may be treated with fumigants such as methyl bromide to meet the needs of the quarantine requirements of importing countries. Irradiation is a non-chemical alternative to substitute the methyl bromide treatment of fresh products. In this research, different cut orchids were irradiated to examine their tolerance to gamma-rays. A 200 Gy dose did inhibit the Dendrobium palenopsis buds from opening, but did not cause visible damage to opened flowers. Doses of 800 and 1000 Gy were damaging because they provoked the flowers to drop from the stem. Cattleya irradiated with 750 Gy did not show any damage, and were therefore eligible for the radiation treatment. Cymbidium tolerated up to 300 Gy and above this dose dropped prematurely. On the other hand, Oncydium did not tolerate doses above 150 Gy.

Kikuchi, Olivia Kimiko

2000-03-01

34

EURAMET.RI(I)-S7 comparison of alanine dosimetry systems for absorbed dose to water measurements in gamma- and x-radiation at radiotherapy levels  

NASA Astrophysics Data System (ADS)

The National Physical Laboratory (NPL), the Physikalisch-Technische Bundesanstalt (PTB) and the Laboratoire National Henri Becquerel (LNE-LNHB) are involved in the European project 'External Beam Cancer Therapy', a project of the European Metrology Research Programme. Within this project, the electron paramagnetic resonance (EPR)/alanine dosimetric method has been chosen for performing measurements in small fields such as those used in IMRT (intensity modulated radiation therapy). In this context, these three National Metrology Institutes (NMI) wished to compare the result of their alanine dosimetric systems (detector, modus operandi etc) at radiotherapy dose levels to check their consistency. This EURAMET.RI(I)-S7 comparison has been performed with the support of the Bureau International des Poids et Mesures (BIPM) which collected and distributed the results as a neutral organization, to ensure the comparison was 'blind'. Irradiations have been made under reference conditions by each laboratory in a 60Co beam and in an accelerator beam (10 MV or 12 MV) in a water phantom of 30 cm × 30 cm × 30 cm in a square field of 10 cm × 10 cm at the reference depth. Irradiations have been performed at known values of absorbed dose to water (Dw) within 10% of nominal doses of 5 Gy and 10 Gy, i.e. between 4.5 Gy and 5.5 Gy and between 9 Gy and 11 Gy, respectively. Each participant read out their dosimeters and assessed the doses using their own protocol (calibration curve, positioning device etc) as this comparison aims at comparing the complete dosimetric process. The results demonstrate the effectiveness of the EPR/alanine dosimetry systems operated by National Metrology Institutes as a method of assuring therapy level doses with the accuracy required. The maximum deviation in the ratio of measured to applied dose is less than 1%. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Garcia, Tristan; Anton, Mathias; Sharpe, Peter

2012-01-01

35

Pulsar and diffuse contributions to the observed galactic gamma radiation  

NASA Technical Reports Server (NTRS)

With the acquisition of satellite data on the energy spectrum of galactic gamma-radiation, it is clear that such radiation has a multicomponent nature. A calculation of the pulsar gamma ray emission spectrum is used together with a statistical analysis of recent data on 328 known pulsars to make a new determination of the pulsar contribution to galactic gamma ray emission. The contributions from diffuse interstellar cosmic ray induced production mechanisms to the total emission are then reexamined. It is concluded that pulsars may account for a significant fraction of galactic gamma ray emission.

Harding, A. K.; Stecker, F. W.

1980-01-01

36

A Device for Search of Gamma-Radiation Intensive Sources at the Radiation Accident Condition  

SciTech Connect

The procedure designed for measuring angular distributions of gamma radiation and for search of gamma radiation intensive sources is described. It is based on application of the original multidetector device ShD-1, for measuring an angular distribution in a complete solid angle (4 pi). The calibration results and data on the angular distributions of intensity of gamma radiation at the roof of Chornobyl NPP ''Shelter'' are presented.

Batiy, Valeriy; Klyuchnykov, A; Kochnev, N; Rudko, Vladimir; shcherbin, vladimir; Yegorov, V; Schmieman, Eric A.

2005-08-08

37

System-Level Radiation Hardening  

NASA Technical Reports Server (NTRS)

Although system-level radiation hardening can enable the use of high-performance components and enhance the capabilities of a spacecraft, hardening techniques can be costly and can compromise the very performance designers sought from the high-performance components. Moreover, such techniques often result in a complicated design, especially if several complex commercial microcircuits are used, each posing its own hardening challenges. The latter risk is particularly acute for Commercial-Off-The-Shelf components since high-performance parts (e.g. double-data-rate synchronous dynamic random access memories - DDR SDRAMs) may require other high-performance commercial parts (e.g. processors) to support their operation. For these reasons, it is essential that system-level radiation hardening be a coordinated effort, from setting requirements through testing up to and including validation.

Ladbury, Ray

2014-01-01

38

Gamma-radiation in non-Markovian Fermi systems  

E-print Network

The gamma-quanta emission is considered within the framework of the non--Markovian kinetic theory. It is shown that the memory effects have a strong influence on the spectral distribution of gamma-quanta in the case of long-time relaxation regime. It is shown that the gamma-radiation can be used as a probe for both the time-reversible hindrance force and the dissipative friction caused by the memory integral.

V. M. Kolomietz; S. V. Radionov; B. V. Reznychenko

2013-12-10

39

External dose estimates for future Bikini Atoll inhabitants. [Gamma Radiation  

Microsoft Academic Search

To evaluate the potential radiation doses that may be received by the returning Bikinians, we surveyed the residual radioactivity on Bikini and Eneu Islands in June of 1975. An integral part of the survey included measurements of gamma-ray exposure rates which are used to estimate external gamma-ray doses. The survey showed that on Bikini Island the rates are highly variable:

P. H. Gudiksen; T. R. Crites; W. L. Robison

1976-01-01

40

Repair effects of exogenous SOD on Bacillus subtilis against gamma radiation exposure.  

PubMed

Superoxide dismutase (SOD) is an enzyme that removes free radicals from cells in many organisms. In order to further characterize these repair effects and their mechanism when subjected to radiation, Bacillus subtilis cells were exposed to gamma radiation and the cell survival rate, intracellular SOD activity, and DNA double-strand breakage were investigated. Vegetative cells of B. subtilis were irradiated by (60)Co gamma radiation at varying doses and subsequently exposed to varying levels of exogenous SOD. Standard plate-count, xanthine oxidase, and pulsed-field gel electrophoresis (PFGE) methods were employed to investigate the repair effects. The results showed that the exogenous SOD could significantly improve cell survival rate and intracellular SOD activity after gamma radiation. The cell survival rate was elevated 30-87 times above levels observed in control samples. Adding exogenous SOD into gamma irradiated cells may dramatically increase intracellular SOD activity (p < 0.01), while percentage of DNA release (PR) values may decrease significantly when cells are treated with SOD. The repair effects were observed to vary with the gamma radiation dose and SOD concentration. These findings suggest that exogenous SOD may have the ability to repair vegetative B. subtilis cell damage after irradiated by gamma radiation. DNA strand scission may also be prevented by addition of SOD. This research contributes to better understanding of protection from the effects of free radicals and their mechanisms, an ongoing process in many organisms that involves the cellular response to gamma radiation, which occurs naturally in soil and water, as well as in unusual cases of high-dosage exposure. PMID:24096311

Chen, Xiaoming; Zhang, E; Fang, Liu; Zhang, Jianguo; Zhu, Jie; He, Wei; Luo, Xuegang

2013-12-01

41

Snowpack snow water equivalent measurement using the attenuation of cosmic gamma radiation  

SciTech Connect

Incoming, background cosmic radiation constantly fluxes through the earth`s atmosphere. The high energy gamma portion of this radiation penetrates many terrestrial objects, including the winter snowpack. The attenuation of this radiation is exponentially related to the mass of the medium through which it penetrates. For the past three winters, a device measuring cosmic gamma radiation--and its attenuation through snow--has been installed at the Central Sierra Snow Laboratory, near Donner Pass, California. This gamma sensor, measuring energy levels between 5 and 15 MeV, has proved to be an accurate, reliable, non-invasive, non-mechanical instrument with which to measure the total snow water equivalent of a snowpack. This paper analyzes three winters` worth of data and discusses the physics and practical application of the sensor for the collection of snow water equivalent data from a remote location.

Osterhuber, R. [Univ. of California, Soda Springs, CA (United States). Central Sierra Snow Lab.; Fehrke, F. [California Dept. of Water Resources, Sacramento, CA (United States); Condreva, K. [Sandia National Labs., Livermore, CA (United States)

1998-05-01

42

Extract of Xylopia aethiopica (Annonaceae) protects against gamma-radiation induced testicular damage in Wistar rats.  

PubMed

Ionizing radiation is an important environmental risk factor and, a major therapeutic agent for cancer treatment. This study was designed to evaluate the protective effect of extract of Xylopia aethiopica (XA) on gamma-radiation-induced testicular damage in rats. Vitamin C (VC) served as the reference antioxidant during the study. The study consists of 4 groups of 11 rats each. Group I received corn oil (vehicle), groups II and IV were pretreated with XA (250 mg/kg) and VC (250mg/kg) for 6 weeks before and 8 weeks after exposure to gamma-radiation; group III was exposed to a single dose of gamma-radiation (5 Gy). Biochemical analysis revealed that gamma-irradiation caused a significant increase (p < .05) in serum and testicular lipid peroxidation (LPO) levels by 217% and 221%, respectively. Irradiated rats had markedly decreased testicular catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and reduced glutathione (GSH) levels. Irradiation resulted in 59% and 40% decreases in spermatozoa motility and live/dead sperm count, respectively, and a 161% increase in total sperm abnormalities. Histologically, testes of the irradiated rats showed extensive degenerative changes in the seminiferous tubules and defoliation of spermatocytes. Supplementation of XA and VC reversed the adverse effects of gamma-radiation on biochemical and histological indices of the rats. These findings demonstrated that Xylopia aethiopica has a protective effect by inhibiting oxidative damage in testes of irradiated rats. PMID:21305847

Adaramoye, Oluwatosin Adekunle; Adedara, Isaac Adegboyega; Popoola, Bosede; Farombi, Ebenezer Olatunde

2010-01-01

43

Mold and aflatoxin reduction by gamma radiation of packed hot peppers and their evolution during storage.  

PubMed

The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25°C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25°C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases. PMID:22856582

Iqbal, Qumer; Amjad, Muhammad; Asi, Muhammad Rafique; Ariño, Agustin

2012-08-01

44

Distribution of terrestrial gamma radiation dose rate in the eastern coastal area of Odisha, India.  

PubMed

Terrestrial gamma radiation is one of the important radiation exposures on the earth's surface that results from the three primordial radionuclides (226)Ra, (232)Th and (40)K. The elemental concentration of these elements in the earth's crust could result in the anomalous variation of the terrestrial gamma radiation in the environment. The geology of the local area plays an important role in distribution of these radioactive elements. Environmental terrestrial gamma radiation dose rates were measured around the eastern coastal area of Odisha with the objective of establishing baseline data on the background radiation level. The values of the terrestrial gamma radiation dose rate vary significantly at different locations in the study area. The values of the terrestrial gamma dose rate ranged from 77 to 1651 nGy h(-1), with an average of 230 nGy h(-1). During the measurement of the terrestrial gamma dose rate, sand and soil samples were also collected for the assessment of natural radionuclides. The activities of (226)Ra, (232)Th and (40)K from these samples were measured using a gamma-ray spectrometry with a NaI(Tl) detector. Activity concentrations of (226)Ra, (232)Th and (40)K ranged from 15.6 to 69 Bq kg(-1) with an average of 46.7 Bq kg(-1), from 28.9 to 973 Bq kg(-1) with an average of 250 Bq kg(-1) and from 139 to 952 Bq kg(-1) with an average of 429, respectively. The detailed significance of these studies has been discussed from the radiation protection point of view. PMID:22874894

Gusain, G S; Rautela, B S; Sahoo, S K; Ishikawa, T; Prasad, G; Omori, Y; Sorimachi, A; Tokonami, S; Ramola, R C

2012-11-01

45

Correction of natural gamma radiation logs for the effects of gamma ray emission from and attenuation by the borehole fluid  

SciTech Connect

Disclosed are a method and a system for natural gamma radiation well logging in which the radiation detected in five energy windows is converted into a log of thorium, uranium and potassium (Th,U,K) which is corrected for the presence of gamma radiation emitting materials (e.g., potassium) and strong gamma radiation attenuators (e.g., barite and/or hematite) in the borehole fluid.

Ellis, D. V.

1985-09-17

46

Effect of gamma radiation on honey quality control  

NASA Astrophysics Data System (ADS)

Honey is one of the most complex substances produced by bees, mainly from the nectar of flowers. Gamma radiation is a technique that can be used to decrease the number of microbiological problems associated with food and increase the shelf life of certain products. The objective of this study was to verify the effect of gamma radiation with source of cobalto-60 (10 kGy) on some parameters used in honey quality control. Seven samples of pure honey were obtained from local markets in Sao Paulo, Brazil, in 2007. The methods used are in accordance with Brazilian Regulations. The physicochemical parameters analyzed were: moisture, HMF, free acidity, pH, sugars and ash. The results showed that gamma radiation, in the dose mentioned above, did not cause significant physicochemical alterations.

Bera, A.; Almeida-Muradian, L. B.; Sabato, S. F.

2009-07-01

47

Nano-Sensitization under gamma rays and fast ion radiation  

NASA Astrophysics Data System (ADS)

The use of heavy compounds to enhance radiation induced damage is a promising approach to improve the therapeutic index of radiotherapy. In order to quantify and control the effects of these radiosensitizers, it is of fundamental interest to describe the elementary processes which take place at the molecular level. Using DNA as a probe, we present a comparison of the damage induced in the presence of platinum compounds exposed to different types of ionizing radiation. We present the results obtained with gamma rays (Linear Energy Transfer (LET) = 0.2 keV.?m-1), fast helium ions He2+ (LET = 2.3 keV.?m-1) and fast carbon ions C6+ (LET = 13 keV.?m-1 and LET = 110 keV.?m-1). The efficiency of two different sensitizers was measured: platinum based molecules (the chloroterpyridine platinum - PtTC) and platinum nanoparticles (PtNP). These experiments show that the two sensitizers are efficiently amplifying molecular damage under photon or ion irradiation. Experiments with a radical scavenger confirmed that these damages are mediated by free radicals for more than 90%. More interestingly, the induction of complex damage, the most lethal for the cells, is amplified by a factor of 1.5 on average if platinum (PtTC and PtNP) is present. As already known, the induction of complex damages increases also with the radiation LET. So, finally, the most significant enhancement of complex damage is observed when ion radiation is combined with platinum induced sensitization.

Porcel, E.; Li, S.; Usami, N.; Remita, H.; Furusawa, Y.; Kobayashi, K.; Le Sech, C.; Lacombe, S.

2012-07-01

48

GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra  

SciTech Connect

The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

Winn, W.G.

1999-07-28

49

Investigation of {gamma} radiation from {sup 178}Hf in the respective (n, n Prime {gamma}) reaction  

SciTech Connect

The spectra and angular distributions of gamma rays were measured in the reaction {sup 178}Hf(n, n Prime {gamma}) induced by a beam of fast reactor neutrons. Data onmultipole mixtures in gamma transitions and a lot of new information about gamma transitions of energy 1.5 to 3.0 MeV were obtained. A comparison of these results with information known from the respective (n, {gamma}) reaction made it possible to refine the schemes of deexcitation of {sup 178}Hf levels at energies above 1.5 MeV, to determine more precisely features of these levels, and to introduce new levels and rotation bands at excitation energies of about 2MeV.

Govor, L. I.; Demidov, A. M.; Kurkin, V. A., E-mail: kurkin@polyn.kiae.su; Mikhailov, I. V. [National Research Center Kurchatov Institute (Russian Federation)

2012-12-15

50

Effects of Gamma Irradiation on Silicon Carbide Semiconductor Radiation Detectors  

Microsoft Academic Search

Silicon carbide (SiC) semiconductor radiation detectors are being developed for alpha-particle, X- and gamma-ray, and fast-neutron energy spectrometry. SiC detectors have been operated at temperatures up to 306degC and have also been found to be highly resistant to the radiation effects of fast-neutron and charged-particle bombardments. In the present work, the alpha-particle response of a SiC detector based on a

Frank H. Ruddy; John G. Siedel

2006-01-01

51

Recent progress in low-level gamma imaging  

SciTech Connect

The CEA's Aladin gamma imaging system has been operated successfully for several years in nuclear plants and during decommissioning projects with additional tools such as gamma spectrometry detectors and dose rate probes. The radiological information supplied by these devices is becoming increasingly useful for establishing robust and optimized decommissioning scenarios. Recent technical improvements allow this gamma imaging system to be operated in low-level applications and with shorter acquisition times suitable for decommissioning projects. The compact portable system can be used in places inaccessible to operators. It is quick and easy to implement, notably for onsite component characterization. Feasibility trials and in situ measurements were recently carried out under low-level conditions, mainly on waste packages and glove boxes for decommissioning projects. This paper describes recent low-level in situ applications. These characterization campaigns mainly concerned gamma emitters with {gamma} energy < 700 keV. In many cases, the localization of hot spots by gamma camera was confirmed by additional measurements such as dose rate mapping and gamma spectrometry measurements. These complementary techniques associated with advanced calculation codes (MCNP, Mercure 6.2, Visiplan and Siren) offer a mobile and compact tool for specific assessment of waste packages and glove boxes. (authors)

Mahe, C.; Girones, Ph.; Lamadie, F.; Le Goaller, C. [CEA/DEN/DDCO/SDSP, CEA/Valrho, BP 17171, 30207 Bagnols sur Ceze Cedex (France)

2007-07-01

52

Induction of macrophage antitumor activity by gamma radiation  

SciTech Connect

The authors have developed a model system for examination of macrophage-mediated tumor cells lysis, using the murine macrophage tumor cell line RAW 264.7. These cells, like normal macrophages, exhibit a strict requirement for interaction with both interferon-..gamma.. (IFN-..gamma.., the priming signal) and bacterial lipopolysaccharide (LPS, the triggering signal) in the development of tumor cytolytic activity. In this system, the priming effects of IFN-..gamma.. decay rapidly following withdrawal of this mediator and the cells become unresponsive to LPS. They have recently observed that gamma radiation of the RAW 264.7 cells results in development of a primed state which is stable and responsive to LPS triggering for a least 48 hours. Irradiation-induced development of the primed phenotype is not solely the result of cytostatic effects as LPS treatment alone results in marked decreases in /sup 3/H-TdR incorporation in the absence of cytolytic potential. In addition to delivering the priming signal for tumor cytotoxicity, irradiation of this cell line results in changes in cell morphology that are typical of activation. Finally, treatment with irradiation results in increased cell surface expression of MHC-encoded Class I antigens; however, Class II antigen expression is not induced. Thus, the effects of gamma radiation on this cell line are strikingly similar to those resulting from incubation with IFN-..gamma...

Lambert, L.; Paulnock, D.M.

1986-03-05

53

Radiation Level Changes at RAM Package Surfaces  

SciTech Connect

This paper will explore design considerations required to meet the regulations that limit radiation level variations at external surfaces of radioactive material (RAM) packages. The radiation level requirements at package surfaces (e.g. TS-R-1 paragraphs 531 and 646) invoke not only maximum radiation levels, but also strict limits on the allowable increase in the radiation level during transport. This paper will explore the regulatory requirements by quantifying the amount of near surface movement and/or payload shifting that results in a 20% increase in the radiation level at the package surface. Typical IP-2, IP-3, Type A and Type B packaging and source geometries will be illustrated. Variations in surface radiation levels are typically the result of changes in the geometry of the surface due to an impact, puncture or crush event, or shifting and settling of radioactive contents.

Opperman, Erich [Washington Savannah River Company] [Washington Savannah River Company; Hawk, Mark B [ORNL] [ORNL; Kapoor, Ashok [U.S. Department of Energy, Office of Packaging and Transportation] [U.S. Department of Energy, Office of Packaging and Transportation; Natali, Ronald [R. B. Natali Consulting, Inc.] [R. B. Natali Consulting, Inc.

2010-01-01

54

Gamma Radiation from PSR B1055-52  

NASA Technical Reports Server (NTRS)

The telescopes on the Compton Gamma Ray Observatory (CGRO) have observed PSR B1055-52 a number of times between 1991 and 1998. From these data, a more detailed picture of the gamma radiation from this source has been developed, showing several characteristics which distinguish this pulsar: the light curve is complex; there is no detectable unpulsed emission; the energy spectrum is flat, with no evidence of a sharp high-energy cutoff up to greater than 4 GeV. Comparisons of the gamma-ray data with observations at longer wavelengths show that no two of the known gamma-ray pulsars have quite the same characteristics; this diversity makes interpretation in terms of theoretical models difficult.

Thompson, D. J.; Bailes, M.; Bertsch, D. L.; Cordes, J.; DAmico, N.; Esposito, J. A.; Finley, J.; Hartman, R. C.; Hermsen, W.; Kanbach, G.; Kaspi, V. M.; Kniffen, D. A.; Kuiper, L.; Lin, Y. C.; Lyne, A.; Manchester, R.; Matz, S. M.; Mayer-Hasselwander, H. A.; Michelson, P. F.; Nolan, P. L.

1999-01-01

55

Gamma Radiation from PSR B1055-52  

NASA Technical Reports Server (NTRS)

The telescopes on the Compton Gamma Ray Observatory (CCRO) have observed PSR B1055-52 a number of times between 1991 and 1998. From these data, a more detailed picture of the gamma radiation from this source has been developed, showing several characteristics which distinguish this pulsar: the light curve is complex; there is no detectable unpulsed emission; the energy spectrum is flat, with no evidence of a sharp high-energy cutoff up to greater than 4 GeV. Comparisons of the gamma-ray data with observations at longer wavelengths show that no two of the known gamma-ray pulsars have quite the same characteristics; this diversity makes interpretation in terms of theoretical models difficult.

Thompson, D. J.; Bailes, M.; Bertsch, D. L.; Cordes, J.; DAmico, N. D.; Esposito, J. A.; Finley, J.; Hartman, R. C.; Hermsen, W.; Kanbach, G.; Kaspi, V. M.; Kniffen, D. A.; Kuiper, L.; Lin, Y. C.; Lyne, A.; Manchester, R.; Matz, S. M.; Mayer-Hasselwander, H. A.; Michelson, P. F.; Nolan, P. L.

1998-01-01

56

Gamma radiation from radon daughters in the atmosphere  

Microsoft Academic Search

The gamma ray flux and ionization from the decay products of :::Rn in the atmosphere and the cor- responding photon energy and angular distributions as a function of height above the air-ground inter- face have been calculated for several vertical mPb and :XBi concentration profiles. These physical properties are compared with the corresponding radiation field resulting from sources in the

Harold L. Beck

1974-01-01

57

Immobilization of stationary phases onto chromatographic supports by gamma radiation  

SciTech Connect

Cobalt-60 gamma radiation has been found to be an effective means of immobilizing stationary phases onto gas and liquid chromatographic supports. The ability of a phase to crosslink was determined to be highly dependent on its chemical structure. Gamma radiation was employed to immobilize Se-30, a methylsilicone, and 216 PS onto Chromosorb WHP for packed column chromatography. The resultant columns exhibited increased thermal stability and a high degree of efficiency. Several blended phases containing varying ratios of Se-30:216 PS were also immobilized onto chromatographic packings. This work was further extended to the immobilization of Se-30 and 216 PS onto fused silica capillaries via gamma radiation. Columns exhibited excellent efficiency and improved thermal stability. An investigation into the role of immobilization of polymeric phases for HPLC was undertaken. Results indicate that gamma radiation can immobilzied polyoctadecylsiloxane and polyoctylsiloxane onto silica surfaces. ESCA and elemental analyses were performed to gain a better understanding of the surface and bulk content of immobilized HPLC packings.

Lyons, E.A.

1987-01-01

58

GABA level, gamma oscillation, and working memory performance in schizophrenia.  

PubMed

A relationship between working memory impairment, disordered neuronal oscillations, and abnormal prefrontal GABA function has been hypothesized in schizophrenia; however, in vivo GABA measurements and gamma band neural synchrony have not yet been compared in schizophrenia. This case-control pilot study (N = 24) compared baseline and working memory task-induced neuronal oscillations acquired with high-density electroencephalograms (EEGs) to GABA levels measured in vivo with magnetic resonance spectroscopy. Working memory performance, baseline GABA level in the left dorsolateral prefrontal cortex (DLPFC), and measures of gamma oscillations from EEGs at baseline and during a working memory task were obtained. A major limitation of this study is a relatively small sample size for several analyses due to the integration of diverse methodologies and participant compliance. Working memory performance was significantly lower for patients than for controls. During the working memory task, patients (n = 7) had significantly lower amplitudes in gamma oscillations than controls (n = 9). However, both at rest and across working memory stages, there were significant correlations between gamma oscillation amplitude and left DLPFC GABA level. Peak gamma frequency during the encoding stage of the working memory task (n = 16) significantly correlated with GABA level and working memory performance. Despite gamma band amplitude deficits in patients across working memory stages, both baseline and working memory-induced gamma oscillations showed strong dependence on baseline GABA levels in patients and controls. These findings suggest a critical role for GABA function in gamma band oscillations, even under conditions of system and cognitive impairments as seen in schizophrenia. PMID:24749063

Chen, Chi-Ming A; Stanford, Arielle D; Mao, Xiangling; Abi-Dargham, Anissa; Shungu, Dikoma C; Lisanby, Sarah H; Schroeder, Charles E; Kegeles, Lawrence S

2014-01-01

59

CdTe low level gamma detectors based on a new crystal growth method  

Microsoft Academic Search

A new method of crystal growth, employing a high pressure, vertical Bridgman approach, was successfully applied to the growth of CdTe gamma-ray detector crystals for application to background-level, low bias dosimeters. Detectors of 1.8-mm thickness were uniformly able to detect background radiation at bias levels below 10 volts and exhibited other desirable features. The new growth method makes it possible

E. Raiskin; J. F. Butler

1988-01-01

60

Parametric gamma-radiation at the anomalous passage conditions  

NASA Astrophysics Data System (ADS)

Dynamical diffraction theory of the parametric gamma-radiation (PGR) from relativistic electrons in a thick crystal with Mössbauer nuclei is considered. A detailed analysis of the influence of suppression of photoabsorption for the radiated ?-quanta at an ideal single crystal is presented taking into account both nuclear resonance and electron scattering of the photons. The obtained results allow one to choose the optimal conditions for the observation of the ?-quanta anomalous passage at the Laue case. It is shown that the radiation intensity is drastically increased at such conditions.

Ahmadi, Abbas; Feranchuk, Ilya

2014-10-01

61

Prompt gamma radiation from fission fragments due to the Strutinsky-Denisov polarisation  

NASA Astrophysics Data System (ADS)

The hard electric dipole radiation from fission fragments of 235U by thermal neutrons is predicted. The radiation arises due to the Strutinsky-Denisov-induced polarisation mechanism. The probability of the radiation is at the level of 0.0025 per fission, which is in agreement with experiment. The angular distribution exhibits left-right asymmetry with respect to the plane perpendicular to the neutron polarisation axis. That means that the emission of gamma quanta at the given angle depends on the neutron polarisation. The asymmetry is at the level of 10-3. This effect is similar to that observed earlier for gamma quanta in binary and alphas in ternary fission. The study of this effect will give information about dissipation of the collective energy of the surface vibration in fragments with large amplitude, and gives a picture of the process of snapping back the nuclear surface.

Karpeshin, F. F.

2010-08-01

62

Development of a neutron/. gamma. ray radiation monitor  

SciTech Connect

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/..gamma.. ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time ..gamma.. spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded ..gamma.. spectra created by the photopeak-Compton edge combination in the plateau portion of the knee response, correcting equations using a linearized approximation to the electron recoil spectrum has been developed and incorporated in the MATXUF2 unfolding code. A neutron/..gamma.. ray discriminator based on the method of Adams and White but using two Analog-To-Digital Converters (ADC's) similar to the design of Morris et al has also been designed and its performance evaluated by using it in combination with MATXUF and MATXUF2 to unfold neutron and ..gamma.. ray spectra for some standard sources and filters. Finally suggestions are given for the incorporation of the software and hardware into a single unit micro processor-based instrument for real time neutron/..gamma.. ray dose and/or spectral measurements.

Korsah, K.J.

1983-01-01

63

Gamma radiation resistant Fabry-Perot fiber optic sensors  

NASA Astrophysics Data System (ADS)

The Nuclear Regulatory Commission (NRC) in 1998 completed a study of emerging technologies that could be applicable to measurement systems in nuclear power plants [H. M. Hashemian [et al.], "Advanced Instrumentation and Maintenance Technologies for Nuclear Power Plants," NUREG/CR-5501 (1998)]. This study concluded that advanced fiber optic sensing technology is an emerging technology that should be investigated. It also indicated that there had been very little research related to performance evaluation of fiber optic sensors in nuclear plant harsh environments, although substantial research has been performed on nuclear radiation effects on optical fibers in the last two decades. A type of Fabry-Perot fiber optic temperature sensor, which is manufactured by Fiso Technologies in Canada, is qualified to be a candidate for potential applications in nuclear radiation environment due to its unique signal processing technique and its resistance to power loss. The gamma irradiation effects on this type of sensors are investigated in this article. Two sensors were irradiated in a gamma irradiation field and one of them was irradiated up to a total gamma dose of 133 Mrad. The sensor on-line performance was monitored during each gamma irradiation test. Furthermore, the sensor static and dynamic performance before and after each irradiation test were evaluated according to the Standard ISA-dS67.06.01 ("Performance Monitoring for Nuclear Safety-Related Instrument Channels in Nuclear Power Plants", Standard ISA-dS67.06.01, Draft 7, Instrument Society of America, 1999). Although several abnormal phenomena were observed, analysis shows that gamma irradiation is not accredited to the abnormal behavior, which implies that this type of sensor is suitable to a gamma irradiation environment with a high gamma dose.

Liu, Hanying; Miller, Don W.; Talnagi, Joseph

2002-08-01

64

The Gamma Transitions, Level Densities and Gamma Strength Function of Isotopes Yb-172 and Sm-153  

E-print Network

This report is presented the level densities and gamma strength function which is extracted from primary gamma transitions of (n,2g) measurement on the Dalat Nuclear Research Reactor (DNRR). The comparisons with others results and model calculations, there are outside the scope of uncertainty. These research results are showed that having of complement research for deformed nucleus in order to evaluate nuclear structure models.

Vuong Huu Tan; Pham Dinh Khang; Nguyen Xuan Hai; Ho Huu Thang; Dao Manh Trinh; Nguyen An Son

2013-08-22

65

Combined Effects of Gamma Radiation and High Dietary Iron on Peripheral Leukocyte Distribution and Function  

NASA Technical Reports Server (NTRS)

Both radiation and increased iron stores can independently increase oxidative damage, resulting in protein, lipid and DNA oxidation. Oxidative stress increases the risk of many health problems including cancer, cataracts, and heart disease. This study, a subset of a larger interdisciplinary investigation of the combined effect of iron overload on sensitivity to radiation injury, monitored immune parameters in the peripheral blood of rats subjected to gamma radiation, high dietary iron or both. Specific immune measures consisted of: (1) peripheral leukocyte distribution, (2) plasma cytokine levels and (3) cytokine production profiles following whole blood mitogenic stimulation

Crucian, Brian E.; Morgan, Jennifer L. L.; Quiriarte, Heather A.; Sams, Clarence F.; Smith, Scott M.; Zwart, Sara R.

2012-01-01

66

Gamma radiation survey of the LDEF spacecraft  

NASA Technical Reports Server (NTRS)

The retrieval of the Long Duration Exposure Facility (LDEF) spacecraft after nearly 6 years in orbit offered a unique opportunity to study the long term buildup of induced radioactivity in the variety of materials on board. The first complete gamma ray survey was conducted of a large spacecraft on LDEF shortly after its return to Earth. A surprising observation was the large Be-7 activity which was seen primarily on the leading edge of the satellite, implying that it was picked up by LDEF in orbit. This is the first known evidence for accretion of a radioactive isotope onto an orbiting spacecraft. Other isotopes seen during the survey, the strongest being Na-22 and Mn-54, are all attributed to activation of spacecraft components in orbit. Be-7 is a spallation product of cosmic rays on nitrogen and oxygen in the upper atmosphere. However, the observed density is much greater than expected due to cosmic ray production in situ. This implies transport of Be-7 from much lower altitudes up to the LDEF orbit.

Phillips, G. W.; King, S. E.; August, R. A.; Ritter, J. C.; Cutchin, J. H.; Haskins, P. S.; Mckisson, J. E.; Ely, D. W.; Weisenberger, A. G.; Piercey, R. B.

1991-01-01

67

Gamma-rays Associated with Nearby Thunderstorms at Ground Level  

E-print Network

The TGF and Energetic Thunderstorm Rooftop Array (TETRA) is an array of NaI scintillators located at rooftop level on the campus of Louisiana State University in Baton Rouge, Louisiana. From July 2010 through March 2014, TETRA has detected 28 millisecond-duration bursts of gamma-rays at energies 50 keV - 2 MeV associated with nearby (thunderstorms. The ability to observe ground-level Terrestrial Gamma Flashes from close to the source allows a unique analysis of the storm cells producing these events. The results of the initial analysis will be presented.

Ringuette, Rebecca; Granger, Douglas; Guzik, T Gregory; Stewart, Michael; Wefel, John P

2014-01-01

68

Radiation resistance testing of high-density polyethylene. [Gamma rays  

SciTech Connect

Mechanical tests following gamma inrradiation and creep tests during irradiation have been conducted on high-density polyethylene (HDPE) to assess the adequacy of this material for use in high-integrity containers (HICs). These tests were motivated by experience in nuclear power plants in which polyethylene electrical insulation detoriorated more rapidly than expected due to radiation-induced oxidation. This suggested that HDPE HICs used for radwaste disposal might degrade more rapidly than would be expected in the absence of the radiation field. Two types of HDPE, a highly cross-linked rotationally molded material and a non-cross-linked blow molded material, were used in these tests. Gamma-ray irradiations were performed at several dose rates in environments of air, Barnwell and Hanford backfill soils, and ion-exchange resins. The results of tensile and bend testing on these materials following irradiation will be presented along with preliminary results on creep during irradiation.

Dougherty, D.R.; Adams, J.W.

1983-01-01

69

The Gamma-ray galactic diffuse radiation and Cerenkov telescopes  

SciTech Connect

By using the PYTHIA version of the Lund Monte Carlo program, we study the photon yield of proton-proton collisions in the energy range between 10 GeV and 1 TeV. The resulting photon spectrum turns out to scale roughly with incident energy. Then, by folding the energy spectrum of cosmic-ray protons with the distribution of HI and CO, the Galactic diffuse emission of {gamma}-rays above 100 GeV is mapped. Prospects for observing that diffuse radiation with atmospheric Cerenkov telescopes are discussed. Present instruments are able to detect the {gamma}-ray glow of the Galactic center. The latter will be mapped by the next generation of telescopes if their energy threshold is decreased. However, a detailed survey of the Galactic ridge will be a real challenge, even in the long term. The MILAGRO project seems more appropriate. Finally, we investigate the {gamma}-ray emission from weakly interacting massive particles clustering at the Galactic center. It has been speculated that those species are a major component of the halo dark matter. We show that their {gamma}-ray signal is swamped in the Galactic diffuse radiation and cannot be observed at TeV energies. {copyright} {ital 1995 The American Astronomical Society.}

Chardonnet, P. [Theoretical Physics Group ENSLAPP, BP110, F-74941 Annecy-le-Vieux Cedex (France)] [Theoretical Physics Group ENSLAPP, BP110, F-74941 Annecy-le-Vieux Cedex (France); [Universite de Savoie, BP1104, 73011 Chambery Cedex (France); Salati, P. [Theoretical Physics Group ENSLAPP, BP110, F-74941 Annecy-le-Vieux Cedex (France)] [Theoretical Physics Group ENSLAPP, BP110, F-74941 Annecy-le-Vieux Cedex (France); [Universite de Savoie, BP1104, 73011 Chambery Cedex (France); [Institut Universitaire de France; Silk, J. [545 Campbell Hall, Astronomy Department, University of California at Berkeley, Berkeley, California 94720 (United States)] [545 Campbell Hall, Astronomy Department, University of California at Berkeley, Berkeley, California 94720 (United States); Grenier, I. [Departement dAstrophysique, Centre dEtudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette Cedex (France)] [Departement dAstrophysique, Centre dEtudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Smoot, G. [Building 50, Room 205, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)] [Building 50, Room 205, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

1995-12-01

70

Recent results on the effect of gamma radiation on the durability and microstructure of DWPF glass  

SciTech Connect

The effect of gamma radiation on the durability and microstructure of a simulated nuclear waste glass from the Savannah River Site has been carefully investigated. Three large pieces of glass were irradiated with a Co-60 source to three doses up to a maximum dose of 3.1 {times} 10{sup 10} rad. Internal samples of the large pieces of irradiated and unirradiated glass were leached in deionized water to investigate durability changes and were examined by transmission electron microscopy (TEM) to investigate microstructure changes. Leach tests were performed in triplicate at 90{degree}C with crushed glass samples in deionized water. A statistical analysis of the results indicated to the 95% confidence level that the radiation did not affect the glass durability. Careful examination by TEM indicated no effect of gamma radiation on the microstructure of the glass although severe damage could be induced by the electron beam from the microscope. 19 refs., 2 figs., 3 tabs.

Bibler, N.E.; Tosten, M.H.; Beam, D.C.

1989-12-31

71

Recent results on the effect of gamma radiation on the durability and microstructure of DWPF glass  

SciTech Connect

The effect of gamma radiation on the durability and microstructure of a simulated nuclear waste glass from the Savannah River Site has been carefully investigated. Three large pieces of glass were irradiated with a Co-60 source to three doses up to a maximum dose of 3.1 {times} 10{sup 10} rad. Internal samples of the large pieces of irradiated and unirradiated glass were leached in deionized water to investigate durability changes and were examined by transmission electron microscopy (TEM) to investigate microstructure changes. Leach tests were performed in triplicate at 90{degree}C with crushed glass samples in deionized water. A statistical analysis of the results indicated to the 95% confidence level that the radiation did not affect the glass durability. Careful examination by TEM indicated no effect of gamma radiation on the microstructure of the glass although severe damage could be induced by the electron beam from the microscope. 19 refs., 2 figs., 3 tabs.

Bibler, N.E.; Tosten, M.H.; Beam, D.C.

1989-01-01

72

Radiation resistance testing of high-density polyethylene. [Gamma rays  

Microsoft Academic Search

Mechanical tests following gamma inrradiation and creep tests during irradiation have been conducted on high-density polyethylene (HDPE) to assess the adequacy of this material for use in high-integrity containers (HICs). These tests were motivated by experience in nuclear power plants in which polyethylene electrical insulation detoriorated more rapidly than expected due to radiation-induced oxidation. This suggested that HDPE HICs used

D. R. Dougherty; J. W. Adams

1983-01-01

73

Annihilation radiation in cosmic gamma-ray bursts  

NASA Astrophysics Data System (ADS)

The emission features observed in the energy spectra of cosmic gasmma-ray bursts imply the existence of two radiation components of comparable intensity. The softer component is similar to the continua of featureless bursts. The fast decrease in the intensity of this radiation with increasing photon energy is apparently due to the neutron star's magnetosphere being opague to hard photons because of the formation of electron-positron pairs in single-photon (gamma, B) and two-photon (gamma, gamma) processes. The hard component originates from the annihilation of electron-positron pairs, its spectrum representing a broad line with an extended power-law wing. Such a shape of the spectrum is apparently due to either thermal broadening in a source with a spatially inhomogeneous and rapidly time-varying plasma temperature, or nonthermal energy distribution of particles in their motion along the magnetic field lines. It is assumed that the sources of these components are spatially separated, the annihilation radiation escaping from the polar regions of a strongly magnetized neutron star in a collimated beam without appreciable attenuation.

Golenetskii, S. V.; Mazets, E. P.; Aptekar, R. L.; Gurian, Iu. A.; Ilinskii, V. N.

1986-07-01

74

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation  

NASA Astrophysics Data System (ADS)

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as radiation shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all induced radioactivity was below the accepted maximum permissible concentrations.

Plaza-Rosado, Heriberto

1991-09-01

75

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation  

NASA Technical Reports Server (NTRS)

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as radiation shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all induced radioactivity was below the accepted maximum permissible concentrations.

Plaza-Rosado, Heriberto

1991-01-01

76

Accumulation of Mn(II) in Deinococcus radiodurans Facilitates Gamma-Radiation Resistance  

SciTech Connect

Deinococcus radiodurans is extremely resistant to ionizing radiation. How this bacterium can grow under chronic gamma-radiation (50 Gy/hour) or recover from acute doses greater than 10 kGy is unknown. We show that D. radiodurans accumulates very high intracellular manganese and low iron levels compared to radiation sensitive bacteria, and resistance exhibits a concentration-dependent response to Mn(II). Among the most radiation-resistant bacterial groups reported, Deinococcus, Enterococcus, Lactobacillus and cyanobacteria spp. accumulate Mn(II). In contrast, Shewanella oneidensis and Pseudomonas putida have high Fe but low intracellular Mn concentrations and are very sensitive. We propose that Mn(II) accumulation facilitates recovery from radiation injury.

Daly, Michael J.; Gaidamakova, E; Matrosova, V; Vasilenko, A; Zhai, M; Venkateswaran, Amudhan; Hess, M; Omelchenko, M V.; Kostandarithes, Heather M.; Makarova, S; Wackett, L. P.; Fredrickson, Jim K.; Ghosal, D

2004-11-05

77

Induction of transpositions of MGE Dm412 by {gamma}-radiation in an isogenic line of Drosophila melanogaster  

SciTech Connect

In an isogenic line of Drosophila, transpositions of mobile genetic elements (MGE) Dm412 were induced by {gamma}-radiation at doses of 300, 800, and 1300 R. The rates of induced transpositions were (for each dose, respectively) 3.9 x 10{sup {minus}3}, 1.0 x 10{sup {minus}2}, and 1.87 x 10{sup {minus}2} events per occupied site per haploid genome of the isogenic line per generation. Thus, the transposition rate increased linearly with the radiation dose. The specific rate of {gamma}-radiation-induced transpositions was (1.3 {+-} 0.6) x 10{sup {minus}5} per occupied site per haploid genome of the isogenic line per Roentgen per generation. {gamma}-Radiation-induced hot transposition sites and haplotypes, very similar to those induced by heat shock, were found. It was suggested that the mechanism of induction by {gamma}-radiation involves the heat shock system. Thus, it is more similar to the mechanism of temperature induction than to the direct mutational effect of {gamma}-radiation. Estimates of induced transposition rates per genome for each dose were calculated as 1.1, 3.0, and 5.6 events, respectively, per genome per generation. This level probably corresponds to the subthreshold level of genomes near the {open_quotes}catastrophic border of transpositional losses.{close_quotes} 21 refs., 1 fig., 4 tabs.

Zabanov, S.A. [Institute of Cytology and Genetics, Novosibirsk (Russian Federation); Vasil`eva, L.A.; Ratner, V.A. [Institute of Cytology and Genetics, Novosibirsk (Russian Federation)]|[Novosibirsk State Univ. (Russian Federation)

1995-06-01

78

The origin of the diffuse background gamma-radiation  

NASA Technical Reports Server (NTRS)

Recent observations have now provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV. There is some evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation have been observed which provide evidence for its origin in nuclear processes in the early stages of the big-band cosmology and tie in these processes with galaxy fromation theory. A crucial test of the theory may lie in future observations of the background radiation in the 100 MeV to 100 GeV energy range which may be made with large orbiting spark-chamber satellite detectors. A discussion of the theoretical interpretations of present data, their connection with baryon symmetric cosmology and galaxy formation theory, and the need for future observations are given.

Stecker, F. W.; Puget, J. L.

1974-01-01

79

Current trends in gamma radiation detection for radiological emergency response  

NASA Astrophysics Data System (ADS)

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of inter-disciplinary research and development has taken place-techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation-the so-called second line of defense.

Mukhopadhyay, Sanjoy; Guss, Paul; Maurer, Richard

2011-09-01

80

Current Trends in Gamma Radiation Detection for Radiological Emergency Response  

SciTech Connect

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of interdisciplinary research and development has taken place–techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation–the so-called second line of defense.

Mukhopadhyay, S., Guss, P., Maurer, R.

2011-09-01

81

A practical method for measuring angular distribution of radiation from multiple gamma sources  

SciTech Connect

Radiation survey data are a necessary prerequisite for planning D and D activities at a nuclear facility. For an individual room with a small number of high level radiation sources whose locations are known a priori, the survey process, shielding calculations, and work planning process are straightforward. However, when the space is large and complex, or when an accident has left process equipment and the space in disarray, gathering survey data while minimizing dose to the surveyor may require specialized equipment and analytical methods. The Object Shelter (OS) that encloses the destroyed Unit 4 at the Chernobyl Nuclear Power Plant (ChNPP) contains many intensive radiation sources such as fuel containing material (solidified melted fuel, fragment spent fuel, and fragmented fresh fuel), destroyed/contaminated piping and mechanical equipment, and contaminated dust and debris from accident recovery. These high intensity radiation sources are scattered throughout the facility in unknown configurations, so it is essential to know the angular distribution of gamma radiation in order to plan work and to design shielding. As previously reported, a prototype tool for measuring angular distribution of gamma radiation was developed, constructed and tested at ChNPP OS. The prototype device, designated ShD-1, consisted primarily of a lead (Pb) sphere containing recessed thermoluminescent detectors (TLDs). ShD-1 was successfully used to collect radiation survey data for planning the largest construction project yet performed at ChNPP OS, the stabilization project. From this application we gained insight into some limitations of the prototype design and report here advancements in the design. The multidetector device for measurement of angular distributions of intensity of gamma - radiation is described. Results of tests of experimental model of device are presented and prospects of use of such device are shown. (authors)

Batiy, V.; Pravdivyj, O.; Stoyanov, O. [Institute for Safety Problems of Nuclear Power Plants, National Academy of Sciences of Ukraine (Ukraine); Kochnev, N.; Selukova, V. [National Science Center -Kharkiv Institute of Physics and Technology (Ukraine); Schmieman, E. [Battelle Memorial Institute (United States)

2007-07-01

82

Shelf life of ground beef patties treated by gamma radiation.  

PubMed

The effects of irradiation on microbial populations in ground beef patties vacuum package and irradiated frozen at target doses of 0.0, 1.0, 3.0, 5.0, and 7.0 kGy were determined. Irradiated samples were stored at 4 or -18 degrees C for 42 days, and mesophilic aerobic plate counts (APCs) were periodically determined. Fresh ground beef (initial APC of 10(2) CFU/g) treated with 3.0, 5.0, and 7.0 kGy was acceptable (< 10(7) CFU/g) for 42 days at 4 degrees C. The 1.0 kGy-treated beef samples were acceptable microbiologically (< 10(7) CFU/g) after 42 days but developed an unacceptable off-odor after 21 days. Shelf life diminished in fresh ground beef patties with an initial APC of 10(4) CFU/g. Only beef patties treated with 7.0 kGy were found to be acceptable at 42 days. Beef patties treated at 1.0 and 3.0 kGy reached spoilage APC levels (> 10(7) CFU/g) by day 14 and 21, respectively, whereas patties treated at 5.0 kGy did not spoil until 42 days. The nonirradiated control samples for both batches of ground beef spoiled within 7 days. Microbial counts in ground beef patties stored at -18 degrees C did not change over the 42-day period. Shelf life of ground beef patties stored at 4 degrees C may be extended with gamma radiation, especially at 5.0 and 7.0 kGy. Initial microbial load in ground beef samples was an important shelf life factor. PMID:9798162

Roberts, W T; Weese, J O

1998-10-01

83

Determination of Carbamate and Organophosphorus Pesticides in Vegetable Samples and the Efficiency of Gamma-Radiation in Their Removal  

PubMed Central

In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena) (n = 16), purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC), and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50%) of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb) and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl) were detected in eggplant samples; the highest carbofuran level detected was 1.86?mg/kg, while phenthoate was detected at 0.311?mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40–48%, 35–43%, and 30–45%, respectively, when a radiation strength of 0.5?kGy was utilized. However, when the radiation dose was increased to 1.0?kGy, the levels of the pesticides were reduced to 85–90%, 80–91%, and 90–95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0?kGy can remove 80–95% of some pesticides. PMID:24711991

Chowdhury, Muhammed Alamgir Zaman; Jahan, Iffat; Karim, Nurul; Alam, Mohammad Khorshed; Rahman, Mohammad Abdur; Moniruzzaman, Mohammed; Gan, Siew Hua; Fakhruddin, Abu Naieum Muhammad

2014-01-01

84

Level densities and gamma-ray strength functions in Sn isotopes  

SciTech Connect

The nuclear level densities of {sup 118,119}Sn and the gamma-ray strength functions of {sup 116,118,119}Sn below the neutron separation energy are extracted with the Oslo method using the ({sup 3}He,alphagamma) and ({sup 3}He,{sup 3}He{sup '}gamma) reactions. The level-density function of {sup 119}Sn displays steplike structures. The microcanonical entropies are deduced from the level densities, and the single neutron entropy of {sup 119}Sn is determined to be 1.7 +- 0.2 k{sub B}. Results from a combinatorial model support the interpretation that some of the low-energy steps in the level density function are caused by neutron pair breaking. An enhancement in all the gamma-ray strength functions of {sup 116-119}Sn, compared to standard models for radiative strength, is observed for the gamma-ray energy region of approx =4-11 MeV. These small resonances all have a centroid energy of 8.0(1) MeV and an integrated strength corresponding to 1.7(9)% of the classical Thomas-Reiche-Kuhn sum rule. The Sn resonances may be due to electric dipole neutron skin oscillations or to an enhancement of the giant magnetic dipole resonance.

Toft, H. K.; Larsen, A. C.; Buerger, A.; Guttormsen, M.; Nyhus, H. T.; Siem, S.; Syed, N. U. H. [Department of Physics, University of Oslo, N-0316 Oslo (Norway); Agvaanluvsan, U. [Stanford University, Palo Alto, California 94305 (United States); MonAme Scientific Research Center, Ulaanbaatar (Mongolia); Mitchell, G. E. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Schiller, A.; Voinov, A. [Department of Physics, Ohio University, Athens, Ohio 45701 (United States)

2010-06-15

85

EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS  

SciTech Connect

The electrochemical properties of ionic liquids (ILs) make them attractive for possible replacement of inorganic salts in high temperature molten salt electrochemical processing of nuclear fuel. To be a feasible replacement solvent, ILs need to be stable in moderate and high doses of radiation without adverse chemical and physical effects. Here, we exposed seven different ILs to a 1.2 MGy dose of gamma radiation to investigate their physical and chemical properties as they related to radiological stability. The azolium-based ILs experienced the greatest change in appearance, but these ILs were chemically more stable to gamma radiation than some of the other classes of ILs tested, due to the presence of aromatic electrons in the azolium ring. All the ILs exhibited a decrease in their conductivity and electrochemical window (at least 1.1 V), both of which could affect the utility of ILs in electrochemical processing. The concentration of the irradiation decomposition products was less than 3 mole %, with no impurities detectable using NMR techniques.

Visser, A; Nicholas Bridges, N; Thad Adams, T; John Mickalonis, J; Mark02 Williamson, M

2009-04-21

86

SAS 2 observations of the earth albedo gamma radiation above 35 MeV  

NASA Technical Reports Server (NTRS)

The earth albedo gamma radiation above 35 MeV in the equatorial region is investigated using observations from the second Small Astronomy Satellite. The zenith angle distribution of the gamma radiation has a peak toward the horizon which is about an order of magnitude more intense than the radiation coming from the nadir, and nearly two orders of magnitude more intense than the gamma radiation from most parts of the sky. The gamma radiation originating from the western horizon is a factor of four more intense than the radiation from the eastern horizon and a factor of three more intense than that from the northern and southern directions. This reflects the geomagnetic effects on the incident cosmic rays whose interactions produce the albedo gamma rays. The variation of the upcoming gamma ray intensity with vertical cutoff rigidity is consistent with the empirical relationship found by Gur'yan et al. (1979).

Thompson, D. J.; Simpson, G. A.; Ozel, M. E.

1981-01-01

87

Gamma radiation induced micronuclei and erythrocyte cellular abnormalities in the fish Catla catla.  

PubMed

Ionizing radiation induced DNA damage in fishes is a scarcely studied topic and very few studies are available in fishes exposed to ionizing radiation using the erythrocyte micronucleus assay under laboratory conditions. Since radionuclides released accidentally or during a nuclear disaster can contaminate inland water bodies, biomonitoring methods are required for assessing the impacts of high and low levels of radiation that may ultimately result in ionizing radiation exposure to both humans and non-human biota. Fresh water fish, Catla catla were subjected to protracted (0.002 Gy/min) and acute (3.2 Gy/min) gamma radiation to a total dose of 5 Gy. Peripheral blood samples were collected at different intervals (days 3, 6, 12, 18, 30, 45, 90, 135, 202) and analyzed by the erythrocyte micronucleus assay. Nuclear anomalies observed were micronuclei (MN), deformed nuclei (DN), nuclear bud (NBu), nuclear bridge (NBr), vacuolated nucleus (VN), binucleated cell (BNC), apoptotic cells (AC) while cytoplasmic abnormalities detected were vacuolated cytoplasm (VC), anisochromasia (AN), echinocytes (EC) and enucleus (EN). Both exposures caused a statistically significant increase in nuclear and cytoplasmic abnormalities that correlated with micronucleus and other nuclear anomalies. However, the extent of damage is higher after an acute exposure lasting for a longer period leading to apoptosis. Nuclear and cytoplasmic abnormalities are the resultants of gamma radiation induced genotoxicity and cytotoxicity. PMID:22771702

Anbumani, S; Mohankumar, Mary N

2012-10-15

88

Health effects of low-level radiation in shipyard workers. Final report: [Draft  

SciTech Connect

The Nuclear Shipyard Workers Study (NSWS) was designed to determine whether there is an excess risk of leukemia or other cancers associated with exposure to low levels of gamma radiation. The study compares the mortality experience of shipyard workers who qualified to work in radiation areas to the mortality of similar workers who hold the same types of jobs but who are not authorized to work in radiation areas. The population consists of workers from six government and two private shipyards.

Matanoski, G.M.

1991-06-01

89

Spectral measurements of direct and scattered gamma radiation at a boiling-water reactor site  

Microsoft Academic Search

Quantitative surveys of direct and scattered gamma radiation emitted from the steam-power conversion systems of a boiling-water reactor and other on-site radiation sources were made using a directionally shielded HPGe gamma spectrometry system. The purpose of this study was to obtain data on the relative contributions and energy distributions of direct and scattered gamma radiation in the site environs. The

R. C. Block; I. L. Preiss; R. M. Ryan; G. J. Vargo

1990-01-01

90

Differentially Expressed Genes Associated with Low-Dose Gamma Radiation  

NASA Astrophysics Data System (ADS)

We have studied low dose radiation induced gene expression alterations in a primary human fibroblast cell line using Agilent's whole human genome microarray. Cells were irradiated with 60Co ?-rays (0; 0.1; 0.5 Gy) and 2 hours later total cellular RNA was isolated. We observed differential regulation of approximately 300-500 genes represented on the microarray. Of these, 126 were differentially expressed at both doses, among them significant elevation of GDF-15 and KITLG was confirmed by qRT-PCR. Based on the transcriptional studies we selected GDF-15 to assess its role in radiation response, since GDF-15 is one of the p53 gene targets and is believed to participate in mediating p53 activities. First we confirmed gamma-radiation induced dose-dependent changes in GDF-15 expression by qRT-PCR. Next we determined the effect of GDF-15 silencing on radiosensitivity. Four GDF-15 targeting shRNA expressing lentiviral vectors were transfected into immortalized human fibroblast cells. We obtained efficient GDF-15 silencing in one of the four constructs. RNA interference inhibited GDF-15 gene expression and enhanced the radiosensitivity of the cells. Our studies proved that GDF-15 plays an essential role in radiation response and may serve as a promising target in radiation therapy.

Hegyesi, Hargita; Sándor, Nikolett; Schilling, Boglárka; Kis, Enik?; Lumniczky, Katalin; Sáfrány, Géza

91

Radiomodifying and anticlastogenic effect of Zingerone on Swiss albino mice exposed to whole body gamma radiation.  

PubMed

The radioprotective effect and antigenotoxic potential of phenolic alkanone, Zingerone (ZO) were investigated in Swiss albino mice exposed to gamma radiation. To study the optimum dose for radiation protection, mice were administered with ZO (10-100mg/kgb.wt.), once daily for five consecutive days. One hour after the last administration of ZO on the fifth day, animals were whole body exposed to 10 Gy gamma radiations. The radioprotective potential was assessed using animal survival at an optimal ZO dose of 20mg/kgb.wt., administered prior to 7-11 Gy. Further, the radioprotective potential of ZO was also analyzed by haemopoietic stem cell survival (CFU) assay, mouse bone marrow micronucleus test and histological observations of intestinal and bone marrow damage. Effect of ZO pretreatment on radiation-induced changes in glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPx) levels was also analyzed. ZO treatment resulted increase in the LD(50/30) by 1.8 Gy (dose reduction factor = 1.2). The number of spleen colonies after whole body irradiation of mice (4.5 or 7.5 Gy) was increased when ZO was administered 1h prior to irradiation. The histological observations indicated a decline in the villus height and crypt number with an increase in goblet and dead cell population in the irradiated group, which was normalized by pretreatment with ZO. A significant (p < 0.001) reduction in micronucleated polychromatic, normochromatic erythrocytes, increased PCE/NCE ratio, increase in the GSH, GST, SOD, CAT and decreased LPx levels were observed in ZO pretreated group when compared to the irradiated animals. Our findings demonstrate the potential of ZO in mitigating radiation-induced mortality and cytogenetic damage, which may be attributed to inhibition radiation-induced decline in the endogenous antioxidant levels and scavenging of radiation-induced free radicals. PMID:19463966

Rao, B Nageshwar; Rao, B S Satish; Aithal, B Kiran; Kumar, M R Sunil

2009-01-01

92

\\Gamma\\Gamma \\Gamma\\Gamma  

E-print Network

\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma yyy yyy \\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma@@####\\Gamma\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma @@@ @@@ ### ### ### ### \\Gamma\\Gamma\\Gamma \\Gamma\\Gamma\\Gamma yyy

Laske, Gabi

93

Simple dynamic electromagnetic radiation detector  

NASA Technical Reports Server (NTRS)

Detector monitors gamma dose rate at particular position in a radiation facility where a mixed neutron-gamma environment exists, thus determining reactor power level changes. Device also maps gamma intensity profile across a neutron-gamma beam.

Been, J. F.

1972-01-01

94

Antioxidative and radioprotective potential of rutin and quercetin in Swiss albino mice exposed to gamma radiation  

PubMed Central

The radioprotective potential of bioflavonoid, rutin (RUT) and quercetin (QRT) was investigated in Swiss albino mice exposed to gamma radiation. The radioprotective potential of RUT and QRT was assessed in pre-treatment group of mice followed on radiation-induced changes in glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) levels were also analyzed. Elevation in the GSH, GST, SOD, CAT, and decreased LPO levels were observed in RUT and QRT pretreated group when compared to the irradiated animals. Furthermore, it was observed that RUT and QRT treatment was found to inhibit various free radicals generated in vitro, viz., 2,2-diphenyl-1-picrylhydrazyl(DPPH), O2, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS)+, and OH in a concentration-dependent manner. This study clearly demonstrates the free radical scavenging action of RUT and QRT, indicating that it may have its potential as a radioprotective agent. Furthermore, the presence of a phenolic group in RUT and QRT is known to contribute to scavenging the radiation-induced free radicals and inhibition of oxidative stress. Present findings demonstrate the potential of RUT and QRT in mitigating radiation-induced oxidative stress, which may be attributed to the inhibition of radiation-induced decline in the endogenous antioxidant levels and scavenging of radiation-induced free radicals. PMID:23776312

Patil, Shrikant L.; Mallaiah, Somashekarappa Hiriyur; Patil, Rajashekar K.

2013-01-01

95

Free radical scavenging alleviates the biomechanical impairment of gamma radiation sterilized bone tissue.  

PubMed

Terminal sterilization of bone allografts by gamma radiation is often essential prior to their clinical use to minimize the risk of infection and disease transmission. While gamma radiation has efficacy superior to other sterilization methods it also impairs the material properties of bone allografts, which may result in premature clinical failure of the allograft. The mechanisms by which gamma radiation sterilization damages bone tissue are not well known although there is evidence that the damage is induced via free radical attack on the collagen. In the light of the existing literature, it was hypothesized that gamma radiation induced biochemical damage to bone's collagen that can be reduced by scavenging for the free radicals generated during the ionizing radiation. It was also hypothesized that this lessening of the extent of biochemical degradation of collagen will be accompanied by alleviation in the extent of biomechanical impairment secondary to gamma radiation sterilization. Standardized tensile test specimens machined from human femoral cortical bone and specimens were assigned to four treatment groups: control, scavenger treated-control, irradiated and scavenger treated-irradiated. Thiourea was selected as the free radical scavenger and it was applied in aqueous form at the concentration of 1.5 M. Monotonic and cyclic mechanical tests were conducted to evaluate the mechanical performance of the treatment groups and the biochemical integrity of collagen molecules were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The native mechanical properties of bone tissue did not change by thiourea treatment only. The effect of thiourea treatment on mechanical properties of irradiated specimens were such that the post-yield energy, the fracture energy and the fatigue life of thiourea treated-irradiated treatment group were 1.9-fold, 3.3-fold and 4.7-fold greater than those of the irradiated treatment group, respectively. However, the mechanical function of thiourea treated and irradiated specimens was not to the level of unirradiated controls. The damage occurred through the cleavage of the collagen backbone as revealed by SDS PAGE analysis. Irradiated specimens did not exhibit a noteworthy amount of intact alpha-chains whereas those irradiated in the presence of thiourea demonstrated intact alpha-chains. Results demonstrated that free radical damage is an important pathway of damage, caused by cleaving the collagen backbone. Blocking the activity of free radicals using the scavenger thiourea reduces the extent of damage to collagen, helping to maintain the mechanical strength of sterilized tissue. Therefore, free radical scavenger thiourea has the potential to improve the functional life-time of the allograft component following transplantation. PMID:16022998

Akkus, Ozan; Belaney, Ryan M; Das, Prasenjit

2005-07-01

96

Modeling Gamma-Radiation from Thunderclouds and Lightning  

NASA Astrophysics Data System (ADS)

Terrestrial gamma-ray flashes are sub-millisecond bursts of energetic radiation originating from thunderclouds in the earth's atmosphere [e.g., Fishman et al., Science, 264, 1313, 1994; Dwyer et al., Space Sci. Rev., 10.1007/s11214-012-9894-0, 2012]. Recent analysis of TGF observations and lightning radio emission indicates that the production of TGFs is normally associated with the initial lightning leader development inside thunderclouds [e.g., Shao et al., J. Geophys. Res., 115, A00E30, 2010; Lu et al., Geophys. Res. Lett., 37, L11806, 2010; Cummer et al., Geophys. Res. Lett., 38, L14810, 2011]. In addition to relatively short TGFs, thunderclouds and lightning can also make minute long gamma-ray glows according to ground-based [e.g., Chilingarian et al., Phys. Rev. D, 82, 043009, 2010] and airborne measurements [e.g., Smith et al., J. Geophys. Res., 116, D20124, 2011]. A viable theory for explaining the gamma-ray production by thunderclouds and lightning is the relativistic feedback discharge mechanism introduced by Dwyer [Geophys. Res. Lett., 30, 2055, 2003]. A comprehensive modeling study of TGFs based on this theory was recently reported in [Dwyer, J. Geophys. Res., 117, A02308, 2012], where many observed TGF aspects were successfully reproduced. In this talk, we report simulation results from a new TGF modeling code developed at Florida Tech that implements the same model as the work of Dwyer [2012]. The code is built on a streamer code that has been used for studying streamer discharges in sprites, lightning and laboratory experiments [e.g., Liu and Pasko, J. Geophys. Res., 109, A04301, 2004]. Components for modeling the transport of runaway electrons and positrons, the feedback process, the gamma-ray production, and the lightning leader propagation have been added. The new code can fully model transport of low energy electrons and ions, ionization, attachment, and recombination. Several simulation cases are reported, showing how single and multiple pulsed TGFs can be produced. Finally, we compare the present work with the gamma-ray observations and the modeling study by Dwyer [2012].

Liu, N.; Dwyer, J. R.

2012-12-01

97

Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons, and  

E-print Network

Radiation-Induced Carcinogenesis: Mechanistically Based Differences between Gamma-Rays and Neutrons: Mechanistically Based Differences between Gamma-Rays and Neutrons, and Interactions with DMBA. PLoS ONE 6(12): e dose/dose rate. Sparsely ionizing radiation (e.g. c-rays) generally produces linear or upwardly curving

Brenner, David Jonathan

98

Effect of acute gamma radiation on some physiological features of lichens  

Microsoft Academic Search

The influence of acute gamma radiation on four physiological characteristics of lichens was investigated. Membrane permeability in irradiated thalli of Cladonia arbuscula, Cetraria islandica and Hypogymnia physodes increased considerably compared to controls. The nitrogen content in Peltigera aphthosa appeared to be stable to acute gamma radiation. Up to 1000 Gy there was no essential decrease in respiration intensity in H.

M. G. Nifontova; A. P. Ravinskaya; I. A. Shapiro

1995-01-01

99

Implication and hazard of radiation level in the building materials  

NASA Astrophysics Data System (ADS)

The natural radioactivity due to radium, thorium, and potassium in building material samples contribute to the radiation dose received by human beings significantly. It is essential to evaluate the activity levels of these nuclides for the assessment of natural radiation dose. Activity concentrations of the gamma emitting primordial radionuclides 232Th, 226Ra, and 40K were measured using high resolution gamma spectrometry technique with high purity germanium (HPGe) detector in building materials: sand, brick, granite, cement and rock, collected from various areas of Gulbarga and Koppal districts. The standard ASTM procedure was followed for the sample preparation. The distribution of radionuclides and variation in activity concentration depend upon the rock formation and the geological properties of the region. The activity of the three radionuclides, 232Th, 226Ra, and 40K, were found to be in the range of 3.1-227.1, 1.6-111, and 23.2-1505 Bq/kg, respectively. The dose related radiological parameters were also calculated for all the samples and the observations show that the activity concentrations of the radionuclides are well within the UNSCEAR limits.

Kerur, Basavaraj R.; Rajeshwari, Tanakanti; Siddanna, Rajesh; Kumar, Anil S.

2013-08-01

100

Search for Charmonium States Decaying to J/\\psi\\gamma \\gamma $ Using Initial-State Radiation Events  

SciTech Connect

We study the processes e{sup +}e{sup -} {yields} (J/{psi}{gamma}{gamma}){gamma} and e{sup +}e{sup -} {yields} (J/{psi}{pi}{sup -}{pi}{sup +}){gamma} where the hard photon radiated from an initial e{sup +}e{sup -} collision with center-of-mass (CM) energy near 10.58 GeV is detected. In the final state J/{psi}{gamma}{gamma} we consider J/{psi}{pi}{sup 0}, J/{psi}{eta}, {chi}{sub c1}{gamma}, and {chi}c{sub 2}{gamma} candidates. The invariant mass of the hadronic final state defines the effective e{sup +}e{sup -} CM energy in each event, so these data can be compared with direct e{sup +}e{sup -} measurements. We report 90% CL upper limits for the integrated cross section times branching fractions of the J/{psi}{gamma}{gamma} channels in the Y (4260) mass region.

Aubert, B.; Barate, R.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; /Barcelona U., ECM; Palano,; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B.; /Bergen U.; Abrams, G.S.; /LBL,

2006-11-30

101

Gamma radiation influence on technological characteristics of wheat flour  

NASA Astrophysics Data System (ADS)

This study aimed at determining the influence of gamma radiation on technological characteristics of wheat (Triticum sativum) flour and physical properties of pan breads made with this flour. The bread formulation included wheat flour, water, milk, salt, sugar, yeast and butter. The ?-amylase activity of wheat flour irradiated with 1, 3 and 9 kGy in a Gammacell 220 (AECL), one day, five days and one month after irradiation was evaluated. Deformation force, height and weight of breads prepared with the irradiated flour were also determined. The enzymatic activity increased—reduction of falling number time—as radiation dose increased, their values being 397 s (0 kGy), 388 s (1 kGy), 343 s (3 kGy) and 293 s (9 kGy) respectively, remaining almost constant over the period of one month. Pan breads prepared with irradiated wheat flour showed increased weight. Texture analysis showed that bread made of irradiated flour presented an increase in maximum deformation force. The results indicate that wheat flour ionizing radiation processing may confer increased enzymatic activity on bread making and depending on the irradiation dose, an increase in weight, height and deformation force parameters of pan breads made of it.

Teixeira, Christian A. H. M.; Inamura, Patricia Y.; Uehara, Vanessa B.; Mastro, Nelida L. d.

2012-08-01

102

Spectral measurements of direct and scattered gamma radiation at a boiling-water reactor site  

NASA Astrophysics Data System (ADS)

Quantitative surveys of direct and scattered gamma radiation emitted from the steam-power conversion systems of a boiling-water reactor and other on-site radiation sources were made using a directionally shielded HPGe gamma spectrometry system. The purpose of this study was to obtain data on the relative contributions and energy distributions of direct and scattered gamma radiation in the site environs. The principal radionuclide of concern in this study is 16N produced by the 16O(n,p) 16N reaction in the reactor coolant. Due to changes in facility operation resulting from the implementation of hydrogen water chemistry (HWC), the amount of 16N transported from the reactor to the main steam system under full power operation is excepted to increase by a factor of 1.2 to 5.0. This increase in the 16N source term in the nuclear steam must be considered in the design of new facilities to be constructed on site as well as the evaluation of existing facilities with repect to ALARA (As Low As Reasonably Achievable) dose limits in unrestricted areas. This study consisted of base-line measurements taken under normal BWR chemistry conditions in October, 1987 and a corresponding set taken under HWC conditions in July, 1988. Ground-level and elevated measurements, corresponding to second-story building height, were obtained. The primary conclusion of this study is that direct radiation from the steam-power conversion system is the predominant source of radiation in the site environs of this reactor and that air scattering (i.e. skyshine) does not appear to be significant.

Block, R. C.; Preiss, I. L.; Ryan, R. M.; Vargo, G. J.

1990-12-01

103

Preparation of polyester\\/gypsum\\/composite using gamma radiation, and its radiation stability  

Microsoft Academic Search

Composites based on pure gypsum and polyester–styrene resin have been prepared using various doses of gamma radiation. Some physical properties of the prepared composites and the influence of irradiation dose on it have been studied as: compression strength, hardness, thermal decomposition temperature in nitrogen or oxygen, and the change in weight in aqueous solutions with different pH values.The glass transition

Zaki Ajji

2005-01-01

104

Studies in feed spoilage: prevention of spoilage in ground corn by gamma radiation  

E-print Network

STUDIES IN FEED SPOILAGE: PREVENTION OF SPOILAGE IN GROUND CORN BY GAMMA RAD ATION A Thesis By Billy Dean Nebb Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in Partial fulfillment of the requirements... Free Fatty Acids 15 Mold Counts- 15 Sterility Tests- 16 RESULTS AND DISCUSSION Use of Gamma Radiation to Prevent Spoilage During Storage-- 18 Doses of Gamma Radiation Required to Inactivate Molds in Corn Containing 15. 5 and 22. 0 Percent Moi...

Webb, Billy Dean

2012-06-07

105

Radiation exposure at ground level by secondary cosmic radiation.  

PubMed

The contribution of the charged component of secondary cosmic radiation to the ambient dose equivalent H*(10) at ground level is investigated using the muon detector MUDOS and a TEPC detector surrounded by the coincidence detector CACS to identify charged particles. The ambient dose equivalent rate H*(10)T as measured with the TEPC/CACS is used to calibrate the MUDOS count rate in terms of H*(10). First results from long-term measurements at the PTB reference site for ambient radiation dosimetry are reported. The air pressure corrected dose rate shows, as expected, a strong correlation with the neutron count rate as measured with the Kiel neutron monitor. The measured seasonal variations exhibit a negative correlation with the temperature changes in the upper layers of the atmosphere where the ground level muons are produced. PMID:15856557

Wissmann, F; Dangendorf, V; Schrewe, U

2005-01-01

106

Excitation of high-lying levels of nuclei in resonance scattering of. gamma. rays from (n,. gamma. ) reactions  

SciTech Connect

The method of resonance scattering of neutron-capture ..gamma.. rays has been used to observe excitation of the nuclear levels 6104 +- 3 keV in Mn and Ni, 5603 +- 2 keV in /sup 113/Cd, and also 5087 +- 5 and 6190 +- 3 keV in /sup 208/Pb. The cross section for resonance scattering of the ..gamma.. rays is determined, and also the values GAMMA/sub ..gamma..//sub 0/ = (180 +- 30)x10/sup -3/ eV, delta = 7.5 +- 2.0 eV and GAMMA/sub ..gamma..//sub 0/ = (175 +- 25)x10/sup -3/ eV, delta = 6.5 +- 2.0 eV respectively for 5603 and 6190 keV levels.

Begzhanov, R.B.; Kobilov, O.S.; Kulabdullaev, G.A.

1988-07-01

107

Relative biological effectiveness of tritiated water to gamma radiation for germ line mutations  

SciTech Connect

The relative biological effectiveness was determined using sex-linked recessive lethals induced in Drosophila spermatozoa as the biological effect. The sex-linked recessive lethal test, a measure of mutations induced in germ cells and transmitted through successive generations, yields a linear dose-response curve in the range used in these experiments. A dose-response curve was determined from three exposures to tritiated water and three exposures to /sup 60/Co gamma radiation. The ratio of the slopes of these two response curves is 2.7 +/- 0.3, yielding a relative biological effectiveness that suggests the tritium beta particle is 2.7 times more effective per unit of energy absorbed in inducing gene mutations transmitted to successive generations than /sup 60/Co gamma radiation. The increase in relative biological effectiveness with higher linear energy transfer for tritium beta radiation strongly suggests that single-strand breaks are repaired by a nearly error-free repair mechanism. Ion tracks with a high density of ions (high linear energy transfer) are more efficient than tracks with a low ion density (low linear energy transfer) in inducing transmissible mutations, suggesting interaction among products of ionization. Since most transmitted mutations induced by ionizing radiation result from strand breakage, interaction probably occurs at this level with double-strand breaks being repaired by an error-prone mechanism yielding transmissible mutations.

Byrne, B.J.; Lee, W.R.

1989-03-01

108

Radiation-induced edema after Gamma Knife treatment for meningiomas.  

PubMed

A retrospective study was performed to analyze some parameters in a consecutive series of 35 Gamma Knife treatments in 34 patients with benign meningiomas. The minimum dose to the tumors was never less than 12 Gy. The follow-up period was from 1 to 3 years. A semiquantitative method of tumor volume assessment was used to measure the tumor response to treatment. The presence and clinical significance of postradiation edema were noted. Even in this short follow-up period, 11 of the 35 tumors were reduced in volume. No tumors increased in size. Edema developed preferentially in nonbasal tumors, especially those around the midline and sagittal sinus. In all but one case where radiation-induced edema was observed was the margin tumor dose 18 Gy or more. It is suggested that doses of 18 Gy or more should probably be avoided in the Gamma Knife treatment of meningiomas and that the greatest care should be taken in selecting non-skull base tumors for this form of treatment. PMID:9032853

Ganz, J C; Schröttner, O; Pendl, G

1996-01-01

109

Galactic Center Gamma Ray Excess in a Radiative Neutrino Mass Model  

E-print Network

The Fermi gamma ray space telescope data have pointed towards an excess of gamma rays with a peak around $1-3$ GeV in the region surrounding the galactic center. This anomalous excess can be described well by a dark matter candidate having mass in the range $31-40$ GeV annihilating into $b\\bar{b}$ pairs with a cross section of $\\langle \\sigma v \\rangle \\simeq (1.4-2.0) \\times 10^{-26} \\; \\text{cm}^3/\\text{s}$. In this work we explore the possibility of having such a dark matter candidate within the framework of a radiative neutrino mass model. The model is a simple extension of the standard model by an additional $U(1)_X$ gauge symmetry where the standard model neutrino masses arise both at tree level as well as radiatively by the anomaly free addition of one singlet fermion $N_R$ and two triplet fermions $\\Sigma_{1R}, \\Sigma_{2R}$ with suitable Higgs scalars. The spontaneous gauge symmetry breaking is achieved in such a way which results in a residual $Z_2$ symmetry and hence providing a stable cold dark matter candidate. We show that the singlet fermionic dark matter candidate in our model can give rise to the galactic center gamma ray excess while satisfying the constraints on relic density, direct detection scattering as well as collider constraints at the same time. We also discuss the compatibility of such a light fermion singlet dark matter with light neutrino mass.

Debasish Borah; Arnab Dasgupta

2014-09-04

110

JITTER RADIATION MODEL OF THE CRAB GAMMA-RAY FLARES  

SciTech Connect

The gamma-ray flares of the Crab nebula detected by the Fermi and AGILE satellites challenge our understanding of the physics of pulsars and their nebulae. The central problem is that the peak energy of the flares exceeds the maximum energy E {sub c} determined by synchrotron radiation loss. However, when turbulent magnetic fields exist with scales {lambda}{sub B} smaller than 2{pi}mc {sup 2}/eB, jitter radiation can emit photons with energies higher than E {sub c}. The scale required for the Crab flares is about two orders of magnitude less than the wavelength of the striped wind. We discuss a model in which the flares are triggered by plunging the high-density blobs into the termination shock. The observed hard spectral shape may be explained by the jitter mechanism. We make three observational predictions: first, the polarization degree will become lower in flares; second, no counterpart will be seen in TeV-PeV range; and third, the flare spectrum will not be harder than {nu}F {sub {nu}}{proportional_to}{nu}{sup 1}.

Teraki, Yuto; Takahara, Fumio, E-mail: teraki@vega.ess.sci.osaka-u.ac.jp [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)] [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)

2013-02-15

111

A gamma-gamma coincidence/anticoincidence spectrometer for low-level cosmogenic (22)Na/(7)Be activity ratio measurement.  

PubMed

In this study, a digital gamma-gamma coincidence/anticoincidence spectrometer was developed and examined for low-level cosmogenic (22)Na and (7)Be in air-filter sample monitoring. The spectrometer consists of two bismuth germanate scintillators (BGO) and an XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The spectrometer design allows a more selective measurement of (22)Na with a significant background reduction by gamma-gamma coincidence events processing. Hence, the system provides a more sensitive way to quantify trace amounts of (22)Na than normal high resolution gamma spectrometry providing a critical limit of 3 mBq within a 20 h count. The use of a list-mode data acquisition technique enabled simultaneous determination of (22)Na and (7)Be activity concentrations using a single measurement by coincidence and anticoincidence mode respectively. PMID:24412563

Zhang, Weihua; Ungar, Kurt; Stukel, Matthew; Mekarski, Pawel

2014-04-01

112

77 FR 62267 - Proposed Extension of Existing Information Collection; Gamma Radiation Surveys  

Federal Register 2010, 2011, 2012, 2013

...at surface operations using X-ray machines, weightometers, nuclear and diffraction units. Nuclear gauges mounted...other types of vessels; gamma rays are used to sense the level...slurries or solids. Gamma rays penetrate the body and...

2012-10-12

113

Radiofungicidal effects of external gamma radiation and antibody-targeted beta and alpha radiation on Cryptococcus neoformans.  

PubMed

We evaluated the clonogenic survival, membrane permeability, metabolic activity (XTT reduction), and apoptosis (FLICA binding) of Cryptococcus neoformans cells subjected to gamma rays from an external source, and beta and alpha particles delivered to fungal cells by capsule-specific antibody. We found that gamma, beta, and alpha radiation affected cells through different pathways. PMID:18378712

Bryan, Ruth A; Huang, Xianchun; Morgenstern, Alfred; Bruchertseifer, Frank; Casadevall, Arturo; Dadachova, Ekaterina

2008-06-01

114

Radiofungicidal Effects of External Gamma Radiation and Antibody-Targeted Beta and Alpha Radiation on Cryptococcus neoformans?  

PubMed Central

We evaluated the clonogenic survival, membrane permeability, metabolic activity (XTT reduction), and apoptosis (FLICA binding) of Cryptococcus neoformans cells subjected to gamma rays from an external source, and beta and alpha particles delivered to fungal cells by capsule-specific antibody. We found that gamma, beta, and alpha radiation affected cells through different pathways. PMID:18378712

Bryan, Ruth A.; Huang, Xianchun; Morgenstern, Alfred; Bruchertseifer, Frank; Casadevall, Arturo; Dadachova, Ekaterina

2008-01-01

115

Radiation effects on silver and zinc battery electrodes. I. Interim report, April-July 1965. [. gamma. radiation  

Microsoft Academic Search

During the initial characterization of silver-zinc cell electrodes, and the study of effects of gamma radiation on them, excessive growth of dendrites from the zinc electrode occurred. Therefore, cadmium electrodes were substituted for zinc in this phase of the work. A silver electrode which had a capacity of 0.8 Ah lost 54 mg of material after a gamma dosage of

G. R. Argue; H. L. Recht; W. A. McCollum

1965-01-01

116

Search for Radiative Penguin Decays B+-->rho+gamma, B0-->rho0gamma, and B0-->omegagamma  

Microsoft Academic Search

A search for the decays B-->rho(770)gamma and B0-->omega(782)gamma is performed on a sample of 211×106 Upsilon(4S)-->BB¯ events collected by the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions: B(B+-->rho+gamma)<1.8×10-6, B(B0-->rho0gamma)<0.4×10-6, and B(B0-->omegagamma)<1.0×10-6 at the 90% confidence level. We use the quark

B. Aubert; R. Barate; D. Boutigny; F. Couderc; J.-M. Gaillard; A. Hicheur; Y. Karyotakis; J. P. Lees; V. Tisserand; A. Zghiche; A. Palano; A. Pompili; J. C. Chen; N. D. Qi; G. Rong; P. Wang; Y. S. Zhu; G. Eigen; I. Ofte; B. Stugu; G. S. Abrams; A. W. Borgland; A. B. Breon; D. N. Brown; J. Button-Shafer; R. N. Cahn; E. Charles; C. T. Day; M. S. Gill; A. V. Gritsan; Y. Groysman; R. G. Jacobsen; R. W. Kadel; J. Kadyk; L. T. Kerth; Yu. G. Kolomensky; G. Kukartsev; G. Lynch; L. M. Mir; P. J. Oddone; T. J. Orimoto; M. Pripstein; N. A. Roe; M. T. Ronan; V. G. Shelkov; W. A. Wenzel; M. Barrett; K. E. Ford; T. J. Harrison; A. J. Hart; C. M. Hawkes; S. E. Morgan; A. T. Watson; M. Fritsch; K. Goetzen; T. Held; H. Koch; B. Lewandowski; M. Pelizaeus; M. Steinke; J. T. Boyd; N. Chevalier; W. N. Cottingham; M. P. Kelly; T. E. Latham; F. F. Wilson; T. Cuhadar-Donszelmann; C. Hearty; N. S. Knecht; T. S. Mattison; J. A. McKenna; D. Thiessen; A. Khan; P. Kyberd; L. Teodorescu; A. E. Blinov; V. E. Blinov; V. P. Druzhinin; V. B. Golubev; V. N. Ivanchenko; E. A. Kravchenko; A. P. Onuchin; S. I. Serednyakov; Yu. I. Skovpen; E. P. Solodov; A. N. Yushkov; D. Best; M. Bruinsma; M. Chao; I. Eschrich; D. Kirkby; A. J. Lankford; M. Mandelkern; R. K. Mommsen; W. Roethel; D. P. Stoker; C. Buchanan; B. L. Hartfiel; S. D. Foulkes; J. W. Gary; B. C. Shen; K. Wang; D. del Re; H. K. Hadavand; E. J. Hill; D. B. Macfarlane; H. P. Paar; Sh. Rahatlou; V. Sharma; J. W. Berryhill; C. Campagnari; B. Dahmes; O. Long; A. Lu; M. A. Mazur; J. D. Richman; W. Verkerke; T. W. Beck; A. M. Eisner; C. A. Heusch; J. Kroseberg; W. S. Lockman; G. Nesom; T. Schalk; B. A. Schumm; A. Seiden; P. Spradlin; D. C. Williams; M. G. Wilson; J. Albert; E. Chen; G. P. Dubois-Felsmann; A. Dvoretskii; D. G. Hitlin; I. Narsky; T. Piatenko; F. C. Porter; A. Ryd; A. Samuel; S. Yang; S. Jayatilleke; G. Mancinelli; B. T. Meadows; M. D. Sokoloff; T. Abe; F. Blanc; P. Bloom; S. Chen; W. T. Ford; U. Nauenberg; A. Olivas; P. Rankin; J. G. Smith; J. Zhang; L. Zhang; A. Chen; J. L. Harton; A. Soffer; W. H. Toki; R. J. Wilson; Q. L. Zeng; D. Altenburg; T. Brandt; J. Brose; M. Dickopp; E. Feltresi; A. Hauke; H. M. Lacker; R. Müller-Pfefferkorn; R. Nogowski; S. Otto; A. Petzold; J. Schubert; K. R. Schubert; R. Schwierz; B. Spaan; J. E. Sundermann; D. Bernard; G. R. Bonneaud; F. Brochard; P. Grenier; S. Schrenk; Ch. Thiebaux; G. Vasileiadis; M. Verderi; D. J. Bard; P. J. Clark; D. Lavin; F. Muheim; S. Playfer; Y. Xie; M. Andreotti; V. Azzolini; D. Bettoni; C. Bozzi; R. Calabrese; G. Cibinetto; E. Luppi; M. Negrini; L. Piemontese; A. Sarti; E. Treadwell; F. Anulli; R. Baldini-Ferroli; A. Calcaterra; R. de Sangro; G. Finocchiaro; P. Patteri; I. M. Peruzzi; M. Piccolo; A. Zallo; A. Buzzo; R. Capra; R. Contri; G. Crosetti; M. Lo Vetere; M. Macri; M. R. Monge; S. Passaggio; C. Patrignani; E. Robutti; A. Santroni; S. Tosi; S. Bailey; G. Brandenburg; K. S. Chaisanguanthum; M. Morii; E. Won; R. S. Dubitzky; U. Langenegger; W. Bhimji; D. A. Bowerman; P. D. Dauncey; U. Egede; J. R. Gaillard; G. W. Morton; J. A. Nash; M. B. Nikolich; G. P. Taylor; M. J. Charles; G. J. Grenier; U. Mallik; J. Cochran; H. B. Crawley; J. Lamsa; W. T. Meyer; S. Prell; E. I. Rosenberg; A. E. Rubin; J. Yi; M. Biasini; R. Covarelli; M. Pioppi; M. Davier; X. Giroux; G. Grosdidier; A. Höcker; S. Laplace; F. Le Diberder; V. Lepeltier; A. M. Lutz; T. C. Petersen; S. Plaszczynski; M. H. Schune; L. Tantot; G. Wormser; C. H. Cheng; D. J. Lange; M. C. Simani; D. M. Wright; A. J. Bevan; C. A. Chavez; J. P. Coleman; I. J. Forster; J. R. Fry; E. Gabathuler; R. Gamet; D. E. Hutchcroft; R. J. Parry; D. J. Payne; R. J. Sloane; C. Touramanis; J. J. Back; C. M. Cormack; P. F. Harrison; F. Di Lodovico; G. B. Mohanty; C. L. Brown; G. Cowan; R. L. Flack; H. U. Flaecher; M. G. Green; P. D. Jackson; T. R. McMahon; S. Ricciardi; F. Salvatore; M. A. Winter; C. L. Davis; J. Allison; N. R. Barlow; R. J. Barlow; P. A. Hart; M. C. Hodgkinson; G. D. Lafferty; A. J. Lyon; J. C. Williams; A. Farbin; W. D. Hulsbergen; A. Jawahery; D. Kovalskyi; C. K. Lae; V. Lillard; D. A. Roberts; G. Blaylock; C. Dallapiccola; K. T. Flood; S. S. Hertzbach; R. Kofler; V. B. Koptchev; T. B. Moore; S. Saremi; H. Staengle; S. Willocq; R. Cowan; G. Sciolla; S. J. Sekula; F. Taylor; R. K. Yamamoto; D. J. Mangeol; P. M. Patel; S. H. Robertson; A. Lazzaro; V. Lombardo; F. Palombo; J. M. Bauer; L. Cremaldi; V. Eschenburg; R. Godang; R. Kroeger; J. Reidy; D. A. Sanders; D. J. Summers; H. W. Zhao; S. Brunet; D. Côté; P. Taras; H. Nicholson; N. Cavallo; F. Fabozzi; C. Gatto; L. Lista; D. Monorchio; P. Paolucci; D. Piccolo; C. Sciacca; M. Baak; H. Bulten; G. Raven; H. L. Snoek; L. Wilden; C. P. Jessop; J. M. Losecco; T. Allmendinger; K. K. Gan; K. Honscheid; D. Hufnagel; H. Kagan; R. Kass; T. Pulliam; A. M. Rahimi

2005-01-01

117

Search for the Radiative Penguin Decays B+ -> rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma  

E-print Network

A search for the decays B --> rho(770) gamma and B0 --> omega(782)gamma is performed on a sample of 211 million Y(4S)->BBbar events collected by the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions BF(B --> rho+ gamma) rho0 gamma) omega gamma) (rho/omega) gamma]<1.2 x 10^-6 and constrain V_td/V_ts< 0.19 at the 90% C.L.

Aubert, B; Boutigny, D; Couderc, F; Gaillard, J M; Hicheur, A; Karyotakis, Yu; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, Michael T; Shelkov, V G; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Çuhadar-Dönszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, A E; Blinov, V E; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Foulkes, S D; Gary, J W; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Zhang, J; Zhang, L; Chen, A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q L; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, Klaus R; Schwierz, R; Spaan, B; Sundermann, J E; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Schrenk, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Lavin, D; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Charles, M J; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Biasini, M; Covarelli, R; Pioppi, M; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F R; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, Erwin; Gamet, R; Hutchcroft, D E; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Harrison, P F; Mohanty, G B; Cowan, G; Flack, R L; Flächer, H U; Green, M G; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Stängle, H; Willocq, S; Cowan, R; Sciolla, G; Sekula, S J; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L M; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cavallo, N; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; LoSecco, J M; Allmendinger, T; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonian, R; Wong, Q K; Brau, J E; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C

2004-01-01

118

Airborne gamma-radiation survey of the Jabel Ishmas Quadrangle, Kingdom of Saudi Arabia  

USGS Publications Warehouse

An airborne gamma-radiation survey system, which includes digital recording and automatic data processing procedures developed by the U. S. Geological Survey Saudi Arabian Project, is used to collect spectral gamma-radiation data as an aid to regional geologic mapping of pediment areas on the Arabian Shield. The areal extent of rock units can generally be distinguished by the intensity of their radiation pattern. Rocks of ultramafic composition have low radiation response, whereas more felsic rocks reflect higher radiation response. Interpretations based on radiometric data enable the geologist to gain some understanding about the geologic setting of an area before he begins field mapping.

Flanigan, Vincent J.

1975-01-01

119

Sensitometry of the response of a new radiochromic film dosimeter to gamma radiation and electron beams  

Microsoft Academic Search

A new radiation-sensitive imaging material, called GafChromic™ Dosimetry Media, offers advances in high-dose radiation dosimetry and high-resolution radiography for gamma radiation and electrons. The potential uses in radiation processing, radiation sterilization of medical devices, population control of insects by irradiation, food irradiation, blood irradiation for organ-transplant immuno-suppression, clinical radiography, and industrial radiography have led to the present sensitometric study over

W. L. McLaughlin; Chen Yun-Dong; C. G. Soares; A. Miller; G. van Dyk; D. F. Lewis

1991-01-01

120

SCATTERED GAMMA RADIATION MEASUREMENTS FROM A LANTHANUM140 CONTAMINATED FIELD  

Microsoft Academic Search

A 90 deg sector of a circle of approximately 500-foot radius was ; contaminated with-a La¹⁴° aqueous solution to an approximate level of 0.65 ; millicuries per square foot as a means of simulating an area approaching an ; infinite contaminated field. Radiation measurements were made in an open hole ; with a PDR-27A radiac instrument to determine the percentage

C. L. Schlemm; A. A. Jr. Anthony

1959-01-01

121

Pair Production and Radiation Effects in Clouds Illuminated by Gamma Ray Sources  

E-print Network

Many classes of gamma-ray sources, such as gamma-ray bursts, blazars, Seyfert galaxies, and galactic black hole sources are surrounded by large amounts of gas and dust. X-rays and gamma-rays that traverse this material will be attenuated by Compton scattering and photoelectric absorption. One signature of an intervening scattering cloud is radiation-hardening by electrons that have been scattered and heated by the incident radiation, as illustrated by a Monte Carlo calculation. Compton scattering provides backscattered photons that will attenuate subsequent gamma rays through \\gamma\\gamma pair-production processes. We calculate the pair efficiency for a cloud illuminated by gamma-ray burst radiation. An analytic calculation of the flux of X-rays and gamma rays Thomson scattered by an intervening cloud is presented. Illuminated clouds near GRBs will form relativistic plasmas containing large numbers of electron-positron pairs that can be detected within ~1-2 days of the explosion before expanding and dissipating. Localized regions of pair annihilation radiation in the Galaxy could reveal gamma-ray sources embedded in dense clouds, or sites of past GRB explosions.

C. D. Dermer; M. Boettcher; E. P. Liang

2001-07-12

122

Nuclear level densities and gamma-ray strength functions in 44,45Sc  

E-print Network

The scandium isotopes 44,45Sc have been studied with the 45Sc(3He,alpha gamma)44Sc and 45Sc(3He,3He' gamma)45Sc reactions, respectively. The nuclear level densities and gamma-ray strength functions have been extracted using the Oslo method. The experimental level densities are compared to calculated level densities obtained from a microscopic model based on BCS quasiparticles within the Nilsson level scheme. This model also gives information about the parity distribution and the number of broken Cooper pairs as a function of excitation energy. The experimental gamma-ray strength functions are compared to theoretical models of the E1, M1, and E2 strength, and to data from (gamma,n) and (gamma,p) experiments. The strength functions show an enhancement at low gamma energies that cannot be explained by the present, standard models.

A. C. Larsen; M. Guttormsen; R. Chankova; T. Loennroth; S. Messelt; F. Ingebretsen; J. Rekstad; A. Schiller; S. Siem; N. U. H. Syed; A. Voinov

2007-06-04

123

Nuclear level densities and {gamma}-ray strength functions in {sup 44,45}Sc  

SciTech Connect

The scandium isotopes {sup 44,45}Sc were studied with the {sup 45}Sc({sup 3}He, {alpha}{gamma}){sup 44}Sc and {sup 45}Sc({sup 3}He, {sup 3}He{sup '}{gamma}){sup 45}Sc reactions, respectively. The nuclear level densities and {gamma}-ray strength functions have been extracted using the Oslo method. The experimental level densities are compared to calculated level densities obtained from a microscopic model based on BCS quasiparticles within the Nilsson level scheme. This model also gives information about the parity distribution and the number of broken Cooper pairs as a function of excitation energy. The experimental {gamma}-ray strength functions are compared to theoretical models of the E1, M1, and E2 strength and to data from ({gamma}, n) and ({gamma},p) experiments. The strength functions show an enhancement at low {gamma} energies that cannot be explained by the present standard models.

Larsen, A. C.; Guttormsen, M.; Ingebretsen, F.; Messelt, S.; Rekstad, J.; Siem, S.; Syed, N. U. H. [Department of Physics, University of Oslo, P. O. Box 1048 Blindern, N-0316 Oslo (Norway); Chankova, R. [North Carolina State University, Raleigh, North Carolina 27695, USA and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Loennroth, T. [Department of Physics, Angstrombo Akademi University, FIN-20500 Angstrombo (Finland); Schiller, A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Voinov, A. [Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States) and Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, RU-141980 Dubna, Moscow region (Russian Federation)

2007-10-15

124

Nuclear level densities and gamma-ray strength functions in 44,45Sc  

E-print Network

The scandium isotopes 44,45Sc have been studied with the 45Sc(3He,alpha gamma)44Sc and 45Sc(3He,3He' gamma)45Sc reactions, respectively. The nuclear level densities and gamma-ray strength functions have been extracted using the Oslo method. The experimental level densities are compared to calculated level densities obtained from a microscopic model based on BCS quasiparticles within the Nilsson level scheme. This model also gives information about the parity distribution and the number of broken Cooper pairs as a function of excitation energy. The experimental gamma-ray strength functions are compared to theoretical models of the E1, M1, and E2 strength, and to data from (gamma,n) and (gamma,p) experiments. The strength functions show an enhancement at low gamma energies that cannot be explained by the present, standard models.

Larsen, A C; Chankova, R; Lönnroth, T; Messelt, S; Ingebretsen, F; Rekstad, J; Schiller, A; Siem, S; Syed, N U H; Voinov, A

2007-01-01

125

Effect of gamma radiation on Aspergillus flavus and Aspergillus ochraceus ultrastructure and mycotoxin production  

NASA Astrophysics Data System (ADS)

The aim of this work was to study the effect of gamma radiation (2 kGy) on Aspergillus flavus and Aspergillus ochraceus ultrastructure. Moreover, the influence on aflatoxin B 1 and ochratoxin A production was also observed. Irradiated A. flavus strain showed a dull orangish colony while control strain showed the typical green color. Minor differences were observed on stipes, metulae and conidia size between control and irradiated A. flavus and A. ochraceus strains. Irradiated fungi showed ultrastructural changes on cell wall, plasmalema and cytoplasm levels. The levels of mycotoxins produced by irradiated strains were two times greater than those produced by control strains. Successive transferences of irradiated strains on malt extract agar allowed the fungus to recuperate morphological characteristics. Although minor changes in the fungal morphology were observed, ultrastructural changes at cell wall level and the increase of mycotoxin production ability were observed. Inappropriate storage of irradiated food and feed would allow the development of potentially more toxicogenic fungal propagules.

Ribeiro, J.; Cavaglieri, L.; Vital, H.; Cristofolini, A.; Merkis, C.; Astoreca, A.; Orlando, J.; Carú, M.; Dalcero, A.; Rosa, C. A. R.

2011-05-01

126

Transmission electron microscopy of simulated DWPF high level nuclear waste glasses following gamma irradiation  

SciTech Connect

In the near future the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) will begin stabilizing high-level radioactive waste using borosilicate glass. The molten waste glass will be poured into stainless steel canisters which, after cooling, will be sealed shut to produce the canistered waste forms. Following interim storage at SRS, the glass-filled canisters will be shipped to an appropriate geologic repository for final disposal. As a result of radioactive decay in the waste, the glasses will absorb large doses of alpha, beta, gamma, neutron, and alpha recoil radiation which raises issues regarding the stability of the canistered waste forms. Thermal analysis testing revealed slight weight changes, which were a function of gamma irradiation, in a highly reduced DWPF simulated waste glass. Transmission electron microscopy (TEM) was performed on these glasses to see if the weight change corresponded to microstructural variations. TEM analyses showed that no microstructural changes were attributable to gamma irradiation. Exposure of the samples to the electron beam in the TEM did result in some changes in the glass microstructures in some cases. These changes were likely due to localized heating of the glass due to interactions with the transmitted electrons.

Marra, J.C.; Bibler, N.E.; Harbour, J.R.; Tosten, M.H.

1994-04-01

127

Hydrogel membranes of PVAl/ clay by gamma radiation  

NASA Astrophysics Data System (ADS)

In the last decades several studies concerning the new methods for drug delivery system have been investigated. A new field known as "smart therapy" involves devices and drug delivery systems to detect, identify and treat the site affected by the disease, not interfering with the biological system. Cutaneous Leishmaniasis is an endemic disease that is characterized by the development of single or multiple localized lesions on exposed areas of skin and one coetaneous treatment could be a potential solution. The aim of this study was to obtain polymeric hydrogel matrices of poly(vinylalcohol)(PVAl) and chitosan with inorganic nanoparticles, which can release a drug according to the need of the treatment of injury caused by leishmania on the skin. The hydrogels matrices were obtained with PVAl/ chitosan and PVAl/ chitosan 0.5; 1.0 and 1.5% laponite RD clay, crosslinked by ionizing gamma radiation with dose of 25 kGy. The techniques used for characterization were swelling, gel fraction, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TGA). After synthesis, the samples were immersed in distilled water and weighed in periods of time until 60 h for the swelling determination. The obtained results have indicated that the swelling of the membranes increases with clay concentration, in consequence of ionic groups present in the clay.

de Oliveira, M. J. A.; Parra, D. F.; Amato, V. S.; Lugão, A. B.

2013-03-01

128

APPLICATION OF JITTER RADIATION: GAMMA-RAY BURST PROMPT POLARIZATION  

SciTech Connect

A high degree of polarization of gamma-ray burst (GRB) prompt emission has been confirmed in recent years. In this paper, we apply jitter radiation to study the polarization feature of GRB prompt emission. In our framework, relativistic electrons are accelerated by turbulent acceleration. Random and small-scale magnetic fields are generated by turbulence. We further determine that the polarization property of GRB prompt emission is governed by the configuration of the random and small-scale magnetic fields. A two-dimensional compressed slab, which contains a stochastic magnetic field, is applied in our model. If the jitter condition is satisfied, the electron deflection angle in the magnetic field is very small and the electron trajectory can be treated as a straight line. A high degree of polarization can be achieved when the angle between the line of sight and the slab plane is small. Moreover, micro-emitters with mini-jet structures are considered to be within a bulk GRB jet. The jet 'off-axis' effect is intensely sensitive to the observed polarization degree. We discuss the depolarization effect on GRB prompt emission and afterglow. We also speculate that the rapid variability of GRB prompt polarization may be correlated with the stochastic variability of the turbulent dynamo or the magnetic reconnection of plasmas.

Mao, Jirong [Astrophysical Big Bang Lab, RIKEN, Saitama 351-0198 (Japan); Wang, Jiancheng, E-mail: jirong.mao@riken.jp [Yunnan Observatory, Chinese Academy of Sciences, 650011 Kunming, Yunnan Province (China)

2013-10-10

129

Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System  

E-print Network

An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.

B. Bromberger; D. Bar; M. Brandis; V. Dangendorf; M. B. Goldberg; F. Kaufmann; I. Mor; R. Nolte; M. Schmiedel; K. Tittelmeier; D. Vartsky; H. Wershofen

2012-01-04

130

Migration levels of PVC plasticisers: Effect of ionising radiation treatment.  

PubMed

Migration levels of commercial plasticisers [di-(2-ethylhexyl) adipate (DEHA) and acetyl tributyl citrate (ATBC)] from polyvinyl chloride (PVC) film into the EU specified aqueous food simulants (distilled water, 3% w/v acetic acid and 10% v/v ethanol) were monitored as a function of time. Migration testing was carried out at 40°C for 10days (EEC, 1993). Determination of the analytes was performed by applying the analytical methodology based on surfactant (Triton X-114) mediated extraction prior to gas chromatographic-flame ionisation detection (GC-FID) recently proposed by our group. The study focuses on the determination of the effect of gamma radiation on plasticiser migration into the selected simulants. PVC cling film used was subjected to ionising treatment with a [(60)Co] source at doses equal to 5, 15 and 25kGy. DEHA and ATBC migration into the EU aqueous simulating solvents was limited, yielding final concentrations in the respective ranges 10-100?g/l and 171-422?g/l; hence, ATBC demonstrated a stronger interaction with all three simulants compared to DEHA. Migration data, with respect to ATBC, showed that the most aggressive simulant seemed to be the 10% ethanol, while in the case of DEHA the 3% aqueous acetic acid exhibited the highest extraction efficiency; distilled water demonstrated the lowest migration in both cases. With regard to PVC treatment with gamma rays, high radiation doses up to 25kGy produced a statistically significant (p<0.05) effect on the migration of both plasticisers. PMID:25214336

Zygoura, Panagiota D; Paleologos, Evangelos K; Kontominas, Michael G

2011-09-01

131

Development of an alpha/beta/gamma detector for radiation monitoring  

NASA Astrophysics Data System (ADS)

For radiation monitoring at the site of nuclear power plant accidents such as Fukushima Daiichi, radiation detectors not only for gamma photons but also for alpha and beta particles are needed because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. We developed a radiation detector that can simultaneously monitor alpha and beta particles and gamma photons for radiation monitoring. The detector consists of three-layered scintillators optically coupled to each other and coupled to a photomultiplier tube. The first layer, which is made of a thin plastic scintillator (decay time: 2.4 ns), detects alpha particles. The second layer, which is made of a thin Gd2SiO5 (GSO) scintillator with 1.5 mol.% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol.% Ce (decay time: 70 ns) detects gamma photons. By using pulse shape discrimination, the count rates of these layers can be separated. With individual irradiation of alpha and beta particles and gamma photons, the count rate of the first layer represented the alpha particles, the second layer represented the beta particles, and the third layer represented the gamma photons. Even with simultaneous irradiation of the alpha and beta particles and the gamma photons, these three types of radiation can be individually monitored using correction for the gamma detection efficiency of the second and third layers. Our developed alpha, beta, and gamma detector is simple and will be useful for radiation monitoring, especially at nuclear power plant accident sites or other applications where the simultaneous measurements of alpha and beta particles and gamma photons are required.

Yamamoto, Seiichi; Hatazawa, Jun

2011-11-01

132

Development of an alpha/beta/gamma detector for radiation monitoring  

SciTech Connect

For radiation monitoring at the site of nuclear power plant accidents such as Fukushima Daiichi, radiation detectors not only for gamma photons but also for alpha and beta particles are needed because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. We developed a radiation detector that can simultaneously monitor alpha and beta particles and gamma photons for radiation monitoring. The detector consists of three-layered scintillators optically coupled to each other and coupled to a photomultiplier tube. The first layer, which is made of a thin plastic scintillator (decay time: 2.4 ns), detects alpha particles. The second layer, which is made of a thin Gd{sub 2}SiO{sub 5} (GSO) scintillator with 1.5 mol.% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol.% Ce (decay time: 70 ns) detects gamma photons. By using pulse shape discrimination, the count rates of these layers can be separated. With individual irradiation of alpha and beta particles and gamma photons, the count rate of the first layer represented the alpha particles, the second layer represented the beta particles, and the third layer represented the gamma photons. Even with simultaneous irradiation of the alpha and beta particles and the gamma photons, these three types of radiation can be individually monitored using correction for the gamma detection efficiency of the second and third layers. Our developed alpha, beta, and gamma detector is simple and will be useful for radiation monitoring, especially at nuclear power plant accident sites or other applications where the simultaneous measurements of alpha and beta particles and gamma photons are required.

Yamamoto, Seiichi [Kobe City College of Technology, 8-3, Gakuen-Higashi-machi, Nishi-ku, Kobe, 651-2194 (Japan); Hatazawa, Jun [Osaka University of Graduate School of Medicine, 2-2, Yamadaoka, Suita-shi, Osaka, 565-0871 (Japan)

2011-11-15

133

This work centers around a state of the art gamma and neutron radiation detector, which is able to display radiation information about its surrounding at every second. Information about the count  

E-print Network

ABSTRACT This work centers around a state of the art gamma and neutron radiation detector, which the count level is displayed along with the energy range of the detected radiation. Currently, similar, allowing workers to stay at a safe distance. The sensor has been characterized using exempt Cs-137 and Co

Abidi, Mongi A.

134

A gamma-ray testing technique for spacecraft. [considering cosmic radiation effects  

NASA Technical Reports Server (NTRS)

The simulated cosmic radiation effect on a spacecraft structure is evaluated by gamma ray testing in relation to structural thickness. A drawing of the test set-up is provided and measurement errors are discussed.

Gribov, B. S.; Repin, N. N.; Sakovich, V. A.; Sakharov, V. M.

1977-01-01

135

Branching fractions and CP-violating asymmetries in radiative B decays to eta K gamma  

E-print Network

We present measurements of the CP-violation parameters S and C for the radiative decay B0-->etaKS0gamma; for B-->etaKgamma we also measure the branching fractions and for B+-->etaK+gamma the time-integrated charge asymmetry ...

Zhao, M.

136

Standoff Performance of HPGe Detectors in Identification of Gamma-Ray Radiation Sources  

Microsoft Academic Search

The detection and identification of radiation sources at distances in the range of 15 meters or more is becoming increasingly important for illicit materials interdiction and the location of lost or orphan sources. In most locations, there is a considerable gamma-ray flux from natural background (NORM) and cosmic- induced nuclides. This gamma-ray flux varies with time, weather conditions, location, and

Ronald M. Keyser; Timothy R. Twomey; Sam Hitch

137

Extending the response of the sum coincidence spectrometer to multiple gamma radiation cascades  

E-print Network

EXTENDING THE RESPONSE OF THE SUM COINCIDENCE SPECTROMETEP TO MULTIPLE GAMMA RADIATION CASCADES A Thesis By VICTOR DEAN HELTON Submitted to the Graduate College of the Texas AEcM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August, l964, Major Subject: Physics EXTENDING THE RESPONSE OF THE SUM COINCIDENCE SPECTROMETER TO MULTIPLE GAMMA RADIATION CASCADES A Thesis By VICTOR DEAN HELTON Approved as to style and content by: i / C airman...

Helton, Victor Dean

2012-06-07

138

Search for radiative penguin decays B(+)-->rho(+)gamma, B(0)-->rho(0)gamma, and B(0)-->omegagamma.  

PubMed

A search for the decays B-->rho(770)gamma and B0-->omega(782)gamma is performed on a sample of 211 x 10(6) Upsilon(4S)-->BB events collected by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions: B(B+-->rho(+)gamma)<1.8 x 10(-6), B(B0-->rho(0)gamma)<0.4 x 10(-6), and B(B0-->omegagamma)<1.0 x 10(-6) at the 90% confidence level. We use the quark model to limit the combined branching fraction B [B-->(rho/omega)gamma]<1.2 x 10(-6), from which we determine a constraint on the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V(td)|/|V(ts)|. PMID:15698065

Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J-M; Hicheur, A; Karyotakis, Y; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Shelkov, V G; Wenzel, W A; Barrett, M; Ford, K E; Harrison, T J; Hart, A J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Cuhadar-Donszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, A E; Blinov, V E; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Foulkes, S D; Gary, J W; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; Macfarlane, D B; Paar, H P; Rahatlou, Sh; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Nesom, G; Schalk, T; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Zhang, J; Zhang, L; Chen, A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q L; Altenburg, D; Brandt, T; Brose, J; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Sundermann, J E; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Schrenk, S; Thiebaux, Ch; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Lavin, D; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Vetere, M Lo; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Chaisanguanthum, K S; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Nikolich, M B; Taylor, G P; Charles, M J; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Yi, J; Biasini, M; Covarelli, R; Pioppi, M; Davier, M; Giroux, X; Grosdidier, G; Höcker, A; Laplace, S; Diberder, F Le; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Chavez, C A; Coleman, J P; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Cormack, C M; Harrison, P F; Lodovico, F Di; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; Green, M G; Jackson, P S; McMahon, T R; Ricciardi, S; Salvatore, F; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Sekula, S J; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cavallo, N; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Snoek, H L; Wilden, L; Jessop, C P; Losecco, J M; Allmendinger, T; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M

2005-01-14

139

Beam size measurement at high radiation levels  

SciTech Connect

At the end of the Stanford Linear Accelerator the high energy electron and positron beams are quite small. Beam sizes below 100 {mu}m ({sigma}) as well as the transverse distribution, especially tails, have to be determined. Fluorescent screens observed by TV cameras provide a quick two-dimensional picture, which can be analyzed by digitization. For running the SLAC Linear Collider (SLC) with low backgrounds at the interaction point, collimators are installed at the end of the linac. This causes a high radiation level so that the nearby cameras die within two weeks and so-called radiation hard'' cameras within two months. Therefore an optical system has been built, which guides a 5 mm wide picture with a resolution of about 30 {mu}m over a distance of 12 m to an accessible region. The overall resolution is limited by the screen thickness, optical diffraction and the line resolution of the camera. Vibration, chromatic effects or air fluctuations play a much less important role. The pictures are colored to get fast information about the beam current, size and tails. Beside the emittance, more information about the tail size and betatron phase is obtained by using four screens. This will help to develop tail compensation schemes to decrease the emittance growth in the linac at high currents. 4 refs., 2 figs.

Decker, F.J.

1991-05-01

140

Galactic Center Gamma Ray Excess in a Radiative Neutrino Mass Model  

E-print Network

The Fermi gamma ray space telescope data have pointed towards an excess of gamma rays with a peak around $1-3$ GeV in the region surrounding the galactic center. This anomalous excess can be described well by a dark matter candidate having mass in the range $31-40$ GeV annihilating into $b\\bar{b}$ pairs with a cross section of $\\langle \\sigma v \\rangle \\simeq (1.4-2.0) \\times 10^{-26} \\; \\text{cm}^3/\\text{s}$. In this work we explore the possibility of having such a dark matter candidate within the framework of a radiative neutrino mass model. The model is a simple extension of the standard model by an additional $U(1)_X$ gauge symmetry where the standard model neutrino masses arise both at tree level as well as radiatively by the anomaly free addition of one singlet fermion $N_R$ and two triplet fermions $\\Sigma_{1R}, \\Sigma_{2R}$ with suitable Higgs scalars. The spontaneous gauge symmetry breaking is achieved in such a way which results in a residual $Z_2$ symmetry and hence providing a stable cold dark mat...

Borah, Debasish

2014-01-01

141

Heterogenization of precious metal catalysts and enzymes by radiation-induced graft copolymerization. [Gamma or ultraviolet radiation  

Microsoft Academic Search

The feasibility of using radiation graft copolymerization for the preparation of supports suitable for the heterogenization of catalysts was examined. To bind metal complexes, radiation graft copolymers of p-styryldiphenylphosphine with a number of trunk polymers were produced. Similarly enzyme immobilization was successful on chemically modified p-nitrostyrene copolymers. Conditions for ..gamma.. and\\/or UV radiation grafting of styrene, p-styryldiphenylphosphine, vinyldiphenylphosphine and p-nitrostyrene

Levot

1983-01-01

142

Effects of interferon-gamma and tumor necrosis factor-alpha on macrophage enzyme levels  

NASA Technical Reports Server (NTRS)

Murine peritoneal macrophages were treated with interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha (TNF). Measurements of changes in acid phosphatase and beta-glucuronidase levels were made as an indication of activation by cytokine treatment. IFN-gamma or TNF-gamma treatment resulted in a significant increase in the activities of both enzymes measured in the cell lysates. This increase was observable after 6 h of incubation, but reached its maximum level after 24 h of incubation. The effect of the treatment of the cell with both cytokines together was additive. No synergistic effect of addition of both cytokines on the enzyme levels was observed.

Pierangeli, Silvia S.; Sonnenfeld, Gerald

1989-01-01

143

Cytoskeletal and functional changes in bioreactor assembled thyroid tissue organoids exposed to gamma radiation  

NASA Technical Reports Server (NTRS)

Fischer rat thyroid cells were grown under low-shear stress in a bioreactor to a stage of organization composed of integrated follicles resembling small thyroid glands prior to exposure to 3 Gray-gamma radiation. Bioreactor tissues and controls (both irradiated and non-irradiated) were harvested at 24, 48, 96 and 144 hours post-exposure. Tissue samples were fixed and fluorescently labeled for actin and microtubules. Tissues were assessed for changes in cytoskeletal components induced by radiation and quantified by laser scanning cytometry. ELISA's were used to quantify transforming growth factor-beta and thyroxin released from cells to the culture supernatant. Tissue architecture was disrupted by exposure to radiation with the structural organization of actin and loss of follicular content the most obviously affected. With time post-irradiation the actin appeared disordered and the levels of fluorescence associated with filamentous-actin and microtubules cycled in the tissue analogs, but not in the flask-grown cultures. Active transforming growth factor-beta was higher in supernatants from the irradiated bioreactor tissue. Thyroxin release paralleled cell survival in the bioreactors and control cultures. Thus, the engineered tissue responses to radiation differed from those of conventional tissue culture making it a potentially better mimic of the in vivo situation.

Green, Lora M.; Patel, Zarana; Murray, Deborah K.; Rightnar, Steven; Burell, Cheryl G.; Gridley, Daila S.; Nelson, Gregory A.

2002-01-01

144

Effects of gamma radiation on raspberries: safety and quality issues.  

PubMed

There is an ever-increasing global demand from consumers for high-quality foods with major emphasis placed on quality and safety attributes. One of the main demands that consumers display is for minimally processed, high-nutrition/low-energy natural foods with no or minimal chemical preservatives. The nutritional value of raspberry fruit is widely recognized. In particular, red raspberries are known to demonstrate a strong antioxidant capacity that might prove beneficial to human health by preventing free radical-induced oxidative stress. However, food products that are consumed raw, are increasingly being recognized as important vehicles for transmission of human pathogens. Food irradiation is one of the few technologies that address both food quality and safety by virtue of its ability to control spoilage and foodborne pathogenic microorganisms without significantly affecting sensory or other organoleptic attributes of the food. Food irradiation is well established as a physical, nonthermal treatment (cold pasteurization) that processes foods at or nearly at ambient temperature in the final packaging, reducing the possibility of cross contamination until the food is actually used by the consumer. The aim of this study was to evaluate effects of gamma radiation on raspberries in order to assess consequences of irradiation. Freshly packed raspberries (Rubus idaeus L.) were irradiated in a (60)Co source at several doses (0.5, 1, or 1.5 kGy). Bioburden, total phenolic content, antioxidant activity, physicochemical properties such as texture, color, pH, soluble solids content, and acidity, and sensorial parameters were assessed before and after irradiation and during storage time up to 14 d at 4°C. Characterization of raspberries microbiota showed an average bioburden value of 10(4) colony-forming units (CFU)/g and a diverse microbial population predominantly composed of two morphological types (gram-negative, oxidase-negative rods, 35%, and filamentous fungi, 41%). The inactivation studies on the raspberries mesophilic population indicated a one log reduction of microbial load (95% inactivation efficiency for 1.5 kGy), in the surviving population mainly constituted by filamentous fungi (79-98%). The total phenolic content of raspberries indicated an increase with radiation doses and a decrease with storage time. The same trend was found for raspberries' antioxidant capacity with storage time. Regarding raspberries physicochemical properties, irradiation induced a significant decrease in firmness compared with nonirradiated fruit. However, nonirradiated and irradiated fruit presented similar physicochemical and sensory properties during storage time. Further studies are needed to elucidate the benefits of irradiation as a raspberries treatment process. PMID:23514071

Verde, S Cabo; Trigo, M J; Sousa, M B; Ferreira, A; Ramos, A C; Nunes, I; Junqueira, C; Melo, R; Santos, P M P; Botelho, M L

2013-01-01

145

Gamma radiation induces growth retardation, impaired egg production, and oxidative stress in the marine copepod Paracyclopina nana.  

PubMed

Accidental nuclear radioisotope release into the ocean from nuclear power plants is of concern due to ecological and health risks. In this study, we used the marine copepod Paracyclopina nana to examine the effects of radioisotopes on marine organisms upon gamma radiation, and to measure the effects on growth and fecundity, which affect population and community structure. Upon gamma radiation, mortality (LD50 - 96 h=172 Gy) in P. nana was significantly increased in a dose-dependent manner in ovigerous P. nana females. For developmental impairment of gamma-irradiated nauplii, we observed growth retardation; in over 30 Gy-irradiated groups, offspring did not grow to adults. Particularly, over 50 Gy-irradiated ovigerous P. nana females did not have normal bilateral egg sacs, and their offspring did not develop normally to adulthood. Additionally, at over 30 Gy, we found dose-dependent increases in oxidative levels with elevated antioxidant enzyme activities and DNA repair activities. These findings indicate that gamma radiation can induce oxidative stress and DNA damage with growth retardation and impaired reproduction. PMID:24632311

Won, Eun-Ji; Lee, Jae-Seong

2014-05-01

146

Pair Production and Radiation Effects in Clouds Illuminated by Gamma Ray Sources  

E-print Network

Many classes of gamma-ray sources, such as gamma-ray bursts, blazars, Seyfert galaxies, and galactic black hole sources are surrounded by large amounts of gas and dust. X-rays and gamma-rays that traverse this material will be attenuated by Compton scattering and photoelectric absorption. One signature of an intervening scattering cloud is radiation-hardening by electrons that have been scattered and heated by the incident radiation, as illustrated by a Monte Carlo calculation. Compton scattering provides backscattered photons that will attenuate subsequent gamma rays through \\gamma\\gamma pair-production processes. We calculate the pair efficiency for a cloud illuminated by gamma-ray burst radiation. An analytic calculation of the flux of X-rays and gamma rays Thomson scattered by an intervening cloud is presented. Illuminated clouds near GRBs will form relativistic plasmas containing large numbers of electron-positron pairs that can be detected within ~1-2 days of the explosion before expanding and dissipati...

Dermer, C D; Liang, E P

2000-01-01

147

Isodose mapping of terrestrial gamma radiation dose rate of Selangor state, Kuala Lumpur and Putrajaya, Malaysia.  

PubMed

A terrestrial gamma radiation survey for the state of Selangor, Kuala Lumpur and Putrajaya was conducted to obtain baseline data for environmental radiological health practices. Based on soil type, geological background and information from airborne survey maps, 95 survey points statistically representing the study area were determined. The measured doses varied according to geological background and soil types. They ranged from 17 nGy h(-1) to 500 nGy h(-1). The mean terrestrial gamma dose rate in air above the ground was 182 ± 81 nGy h(-1). This is two times higher than the average dose rate of terrestrial gamma radiation in Malaysia which is 92 nGy h(-1) (UNSCEAR 2000). An isodose map was produced to represent exposure rate from natural sources of terrestrial gamma radiation. PMID:24787672

Sanusi, M S M; Ramli, A T; Gabdo, H T; Garba, N N; Heryanshah, A; Wagiran, H; Said, M N

2014-09-01

148

Low Level Gamma Spectroscopy Measurements of Radium and Cesium in Lucerne (Medicago Sativa)  

SciTech Connect

Nineteen years after Chernobyl nuclear accident, activity concentration of 137Cs still could be detected in food and soil samples in Central and Eastern Europe. In this paper radiation levels of radium and cesium in Lucerne will be presented. It is a perennial plant with a deep root system and it is widely grown throughout the world as forage for cattle. The samples of Lucerne were taken from twelve different locations in Vojvodina in the summer period July-September 2004. The samples were specially dried on the air and after that ground, powdered and mineralized by method of dry burning on the temperature of 450 deg. C. Gamma spectrometry measurements of the ash were performed by means of actively shielded germanium detector with maximal background reduction. For cesium 137Cs 10 mBq/kg order of magnitude detection limits were achieved.

Fokapic, S.; Bikit, I.; Mrda, D.; Veskovic, M.; Slivka, J. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 4, 21 000 Novi Sad (Serbia); Mihaljev, Z. [Scientific Veterinary Institute, Rumenacki put 20, 21 000 Novi Sad (Serbia); Cupic, Z. [Research Institute for Reproduction, A.I. and Embryo Transfer Temerin, 21235 Temerin, Industrijska zona bb. (Serbia)

2007-04-23

149

Comptonization of diffuse ambient radiation by a relativistic jet: The source of gamma rays from blazars?  

NASA Technical Reports Server (NTRS)

Recent Energy Gamma Ray Experiment Telescope (EGRET) observations of blazars have revealed strong, variable gamma-ray fluxes with no signatures of gamma-ray absorption by pair production. This radiation probably originates from the inner parts of relativistic jets which are aimed nearly toward us. On sub-parsec scales, the jet will be pervaded by radiation from the broad-line region, as well as by photons from the central continuum source (some of which will be scattered by thermal plasma). In a frame moving with the relativistic outflow, the energy of this ambient radiation would be enhanced. This radiation would be Comptonized by both cold and relativistic electrons in the jet, yielding (in the observer's frame) a collimated beam of X-rays and gamma rays. On the assumption that this process dominates self-Comptonization of synchrotron radiation, we develop a self-consistent model for variable gamma-ray emission, involving a single population of relativistic electrons accelerated by a disturbance in the jet. The spectral break between the X-ray and gamma-ray band, observed in 3C 279 and deduced for other blazars, results from inefficient radiative cooling of lower energy electrons. The existence of such a break strongly favors a model involving Comptonization of an external radiation field over a synchrotron self-Compton model. We derive constraints on such model parameters as the location and speed of the source, its dimensions and internal physical parameters, the maximum photon energies produced in the source, and the density and distribution of ambient radiation. Finally, we discuss how observations might discriminate between our model and alternative ones invoking Comptonization of ambient radiation.

Sikora, Marek; Begelman, Mitchell C.; Rees, Martin J.

1994-01-01

150

Reliability studies on Si PIN photodiodes under Co-60 gamma radiation  

SciTech Connect

Silicon PIN photodiodes were fabricated with 250 nm SiO{sub 2} antireflective coating (ARC). The changes in the electrical characteristics, capacitance-voltage characteristics and spectral response after gamma irradiation are systematically studied to estimate the radiation tolerance up to 10 Mrad. The different characteristics studied in this investigation demonstrate that Si PIN photodiodes are suitable for high radiation environment.

Prabhakara Rao, Y. P. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore, Karnataka-560013 (India) and Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Praveen, K. C.; Gnana Prakash, A. P. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Rani, Y. Rejeena [Integrated Circuits Division, Bharat Electronics Limited, Bangalore, Karnataka-560013 (India)

2013-02-05

151

Gamma Ray Bursts from Interaction of Relativistic Flows with Radiation Fields  

E-print Network

Relativistic flows resulting from sudden explosive events upscatter ambient interstellar photons of local radiation fields. For Lorentz factor $ > 100$ and dense optical - UV radiation fields the emergent signal is a typical gamma ray burst. Presumably the explosions occur in dense globular clusters or in galactic nuclei, at cosmological distances.

Amotz Shemi

1994-04-20

152

THE CALCULATION OF THE GAMMA SHIELDING PROTECTION IN EXPANDING RADIATION FIELDS  

Microsoft Academic Search

The usual, purely exponential calculation of shield thicknesses for ; gamma radiators supplies minimum values which in many cases cannot provide the ; desired protection, since the influence of secondary radiation causcd by single ; or multiple Compton processes is not taken into consideration in the exponential ; calculation. By applying the dose build-up factor B, which can be represented

Plesch

1958-01-01

153

Extragalactic gamma Radiation: Use of Galaxy Counts as a Galactic Tracer.  

National Technical Information Service (NTIS)

A derivation of the extragalactic diffuse gamma radiation with energies above 35 MeV was carried out using galaxy counts as a tracer of galactic matter. The extragalactic radiation has a differential photon number spectrum which may be expressed as a powe...

D. J. Thompson, C. E. Fichtel

1982-01-01

154

Formation of radiation defects in bismuth and antimony chalcogenide solid solutions under small doses of gamma radiation  

NASA Astrophysics Data System (ADS)

The paper presents an experimental investigation of the effects of small doses of reactor gamma-rays (simulating cosmic gamma rays) on solid solutions of n-type Ni2Te(2.4)Se(0.6) doped with ZnCl2, and p-type Sb(1.48)Bi(0.52)Te3 doped with Te and Pb. A model for the formation of radiation defects is proposed which is based on the impact-ionization interaction of gamma rays with the crystal lattice.

Gorelik, S. S.; Okhotin, A. S.; Sklokin, F. N.

155

Terrestrial gamma radiation dose rates (TGRD) from surface soil in Negeri Sembilan, Malaysia  

NASA Astrophysics Data System (ADS)

Baseline data on background radiation levels allows for future assessment of possible changes in natural radionuclide concentrations, either as a result of geological processes or radioactive contamination. We have measured terrestrial gamma radiation dose-rates (TGRD) from surface soils throughout accessible areas in the Peninsular Malaysia state of Negeri Sembilan (NS). Dose rate measurements were carried out using a NaI (TI) scintillation survey meter, encompassing 1708 locations, covering about 73% of the 6645 km2 of the land area in NS. This has allowed development of a TGRD contour map, plotted using WinSurf software. The range of measured TGRD was from 71±3 nGy/h up to 1000±11 nGy/h. The greatest measured TGRD was obtained in an area covered by soil types originating from igneous rock of granitic formations, while the least value of TGRD was observed in an area covered by limestone composed of calcite mineral, mostly found near river and coastal areas. Mean values of TGRD across the seven districts of NS ranged from 244±7 nGy/h to 458±13 nGy/h, the global mean being 330±8 nGy/h compared to a mean value of 92 nGy/h and 59 nGy/h for Malaysia and the world, respectively. The average annual dose from such terrestrial gamma radiation dose-rates to an individual residing in NS, assuming a tropical rural setting, is estimated to be 0.96 mSv per year.

Norbani, Nor Eliana; Abdullah Salim, Nazaratul Ashifa; Saat, Ahmad; Hamzah, Zaini; Ramli, Ahmad Termizi; Wan Idris, Wan Mohd Rizlan; Jaafar, Mohd Zuli; Bradley, David A.; Abdul Rahman, Ahmad Taufek

2014-11-01

156

GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION  

SciTech Connect

The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.

Turick, C.; Ekechukwu, A.; Milliken, C.

2011-05-17

157

Radiation streaming and skyshine evaluation for a proposed low-level radioactive waste assured isolation facility.  

PubMed

Texas is investigating the idea of building a long term waste storage facility, also known as an Assured Isolation Facility. This is an above-ground, retrievable low-level radioactive waste storage facility. A preliminary, scoping-level analysis has been extended to consider more complex scenarios of radiation streaming and skyshine by using MCNP to model the facility in greater detail. Using bounding source term assumptions, the radiation doses and dose rates are found to exceed applicable limits by an order of magnitude. By altering the facility design to fill in the hollow cores of the prefabricated concrete slabs used in the roof over the "high-gamma" rooms where the waste with greatest gamma radiation intensity is stored, dose rates outside the facility decrease by an order of magnitude. With the modified design, the annual dose at the site fenceline is less than the 1 mSv annual limit for exposure of the public. Within the site perimeter, modifying the roof results in an order of magnitude drop in the dose rate for personnel outside the facility and on the facility roof, as well as a significant drop inside the facility. Radiation streaming inside the facility can be lowered almost two orders of magnitude by placing operational restrictions to keep at least two rows of waste containers in front of the high-gamma room to cut down on the size of the path for streaming. PMID:13678291

Arno, Matthew; Hamilton, Ian S

2003-10-01

158

Galactic plane gamma radiation. [SAS-2 and COS-b observations  

NASA Technical Reports Server (NTRS)

Analysis of the complete data from SAS-2 accentuates the fact that the distribution of galactic gamma radiation has several similarities to that of other large-scale tracers of galactic structure. The gamma radiation shows no statistically significant variation with direction, and the spectrum seen along the plane is the same as that derived for the galactic component of the gamma radiation at high latitude. This uniformity of the energy spectrum, the smooth decrease in intensity as a function of galactic latitude, and the absence of any galactic gamma ray sources at high latitudes argue in favor of a diffuse origin for most of the galactic gamma radiation, rather than a collection of localized sources. All the localized sources identified in the SAS 2 data are associated with known compact objects on the basis of observed periodicities, except gamma195+5 Excluding those SAS 2 sources observed by COS-B and two other excesses (CG 312-1 and CG333+0) visible in the SAS 2 data associated with tangential directions of spiral arms, thera are eight remaining new sources in the COS-B catalog.

Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.; Fichtel, C. E.; Ogelman, H. B.; Tuner, T.; Ozel, M. E.

1978-01-01

159

Radiation chemistry of salt-mine brines and hydrates. [Gamma radiation  

SciTech Connect

Certain aspects of the radiation chemistry of NaCl-saturated MgCl/sub 2/ solutions and MgCl/sub 2/ hydrates at temperatures in the range of 30 to 180/sup 0/C were investigated through experiments. A principal objective was to establish the values for the yields of H/sub 2/ (G(H/sub 2/)) and accompanying oxidants in the gamma-ray radiolysis of concentrated brines that might occur in waste repositories in salt. We concluded that G(H/sub 2/) from gamma-irradiated brine solution into a simultaneously irradiated, deaerated atmosphere above the solution is between 0.48 and 0.49 over most of the range 30 to 143/sup 0/C. The yield is probably somewhat lower at the lower end of this range, averaging 0.44 at 30 to 45/sup 0/C. Changes in the relative amounts of MgCl/sub 2/ and NaCl in the NaCl-saturated solutions have negligible effects on the yield. The yield of O/sub 2/ into the same atmosphere averages 0.13, independent of the temperature and brine composition, showing that only about 50% of the radiolytic oxidant that was formed along with the H/sub 2/ was present as O/sub 2/. We did not identify the species that compose the remainder of the oxidant. We concluded that the yield of H/sub 2/ from a gamma-irradiated brine solution into a simultaneously irradiated atmosphere containing 5 to 8% air in He may be greater than the yield in deaerated systems by amounts ranging from 0% for temperatures of 73 to 85/sup 0/C, to about 30 and 40% for temperatures in the ranges 100 to 143/sup 0/C and 30 to 45/sup 0/C, respectively. We did not establish the mechanism whereby the air affected the yields of H/sub 2/ and O/sub 2/. The values found in this work for G(H/sub 2/) in deaerated systems are in approximate agreement with the value of 0.44 for the gamma-irradiation yield of H/sub 2/ in pure H/sub 2/O at room temperature. They are also in agreement with the values predicted by extrapolation from the findings of previous researchers for the value for G(H/sub 2/) in 2 M NaCl solutions at room temperature.

Jenks, G.H.; Walton, J.R.; Bronstein, H.R.; Baes, C.F. Jr.

1981-07-01

160

X-ray and gamma-ray radiation from the switched-off radiopulsars  

Microsoft Academic Search

Pulsars which cease generating electron-positron avalanches feature magnetic dipole radiation that is transformed at the 'light radius' into hard radiation. The X-ray and gamma rays are produced in a plasma caused by ionization of interstellar neutral hydrogen. The dipole radiation pushes away interstellar material once the positron-electron avalanche ejection has stopped. However, interstellar neutral hydrogen is captured by the pulsar

A. I. Tsygan

1983-01-01

161

In situ measurement of refractive index changes induced by gamma radiation in germanosilicate fibers  

Microsoft Academic Search

We propose a technique to measure in situ the refractive index changes induced by ionizing radiation in single-mode optical fibers. This change can be derived from the channel drift appearing in narrow channel wavelength-division-multiplexing couplers exposed to gamma radiation. We measured a radiation-induced refractive index change of about 5 10-6\\/kGy[H2O] at low doses and 5 10-7\\/kGy[H2O] at higher doses. No

A. Fernandez Fernandez; B. Brichard; F. Berghmans

2003-01-01

162

Distributions of Secondary Muons at Sea Level from Cosmic Gamma Rays Below 10 TeV  

SciTech Connect

The FLUKA Monte Carlo program is used to predict the distributions of the muons which originate from primary cosmic gamma rays and reach sea level. The main result is the angular distribution of muons produced by vertical gamma rays which is necessary to predict the inherent angular resolution of any instrument utilizing muons to infer properties of gamma ray primaries. Furthermore, various physical effects are discussed which affect these distributions in differing proportions.

Roesler, Stefan

2001-07-31

163

Evaluation of the Combined Effects of Gamma Radiation and High Dietary Iron on Peripheral Leukocyte Distribution and Function  

NASA Technical Reports Server (NTRS)

NASA is concerned with the health risks to astronauts, particularly those risks related to radiation exposure. Both radiation and increased iron stores can independently increase oxidative damage, resulting in protein, lipid and DNA oxidation. Oxidative stress increases the risk of many health problems including cancer, cataracts, and heart disease. This study, a subset of a larger interdisciplinary investigation of the combined effect of iron overload on sensitivity to radiation injury, monitored immune parameters in the peripheral blood of rats subjected to gamma radiation, high dietary iron or both. Specific immune measures consisted of (A) peripheral leukocyte distribution; (B) plasma cytokine levels; (C) cytokine production profiles following whole blood stimulation of either T cells or monocytes.

Crucian, Brian E.; Morgan, Jennifer L. L.; Quiriarte, Heather A.; Sams, Clarence F.; Smith, Scott M.; Zwart, Sara R.

2011-01-01

164

Galactic cosmic ray radiation levels in spacecraft on interplanetary missions  

NASA Technical Reports Server (NTRS)

Using the Langley Research Center Galactic Cosmic Ray (GCR) transport computer code (HZETRN) and the Computerized Anatomical Man (CAM) model, crew radiation levels inside manned spacecraft on interplanetary missions are estimated. These radiation-level estimates include particle fluxes, LET (Linear Energy Transfer) spectra, absorbed dose, and dose equivalent within various organs of interest in GCR protection studies. Changes in these radiation levels resulting from the use of various different types of shield materials are presented.

Shinn, J. L.; Nealy, J. E.; Townsend, L. W.; Wilson, J. W.; Wood, J.S.

1994-01-01

165

LETHAL EFFECTS OF GAMMA RADIATION OF NEUROSPORA CONIDIA  

Microsoft Academic Search

Buffered aqueous solutions of AET showed marked sensitivity to ionizing ; radiation. Two methods of determining the concentration of sulfhydryl groups ; were used with comparable results. The destruction of sulfhydryl groups is ; directly dependent on radiation dose. The high yield suggests that a chain-type ; reaction may account for the radiation sensitivity. I deoxygenated samples, the ; radtation

Gafford

1957-01-01

166

High total dose gamma radiation assessment of commercially available SiGe heterojunction bipolar transistors  

NASA Astrophysics Data System (ADS)

Maintenance tasks of the future International Experimental Thermonuclear fusion Reactor (ITER) will require communication links between the remotely operated equipment in the reactor vessel and the control room, some of which need to be radiation tolerant up to MGy dose levels. As a key element of opto-electronic transceivers, we therefore assessed the DC behavior of a commercial-off-the-shelf (COTS) SiGe heterojunction bipolar transistor (HBT) under gamma radiation up to 15 MGy, with dose rates from 160 Gy/h to 27 kGy/h. Our in-situ measurements of the forward DC current gain (hfe) present a limited loss of about 30 % for a base current of 100 ?A, with a dependence on the biasing conditions and a thermally activated recovery. These first ever reported results up to MGy levels allow us to design circuit-hardened driving electronics for both photonic transmitters and receivers, enabling high bandwidth communications applied in a fusion reactor environment.

Van Uffelen, Marco; Geboers, Sam; Leroux, Paul; Berghmans, Francis

2005-09-01

167

Gamma-radiation-induced degradation of actively pumped single-mode ytterbium-doped optical fibers  

NASA Astrophysics Data System (ADS)

The integration of optical components into the digital processing units of satellite subsystems has the potential to remove interconnect bottlenecks inherent to the volume, mass, complexity, reliability and crosstalk issues of copper-based interconnects. Assuming on-board high-bandwidth communications will utilize passive optical fibers as a communication channel, this work investigates the impact of gamma irradiation from a Co-60 source on both passive optical fibers and ytterbium-doped single-mode fibers operated as amplifiers for a 1060-nm light source. Standard optical patch cables were evaluated along with active Yb-doped double-clad fibers. Varied exposure times and signal transmission wavelengths were used to investigate the degradation of the fibers exposed to total doses above 100 krad (Si). The effect on the amplified signal gain was studied for the Yb-doped fibers. The increased attenuation in the fibers across a broad wavelength range in response to multiple levels of gamma radiation exposure along with the effect that the increased attenuation has on the actively pumped Yb-doped fiber amplifier performance, is discussed.

Singleton, B.; Petrosky, J.; Pochet, M.; Usechak, N. G.; Francis, S. A.

2014-03-01

168

Measurement of outdoor terrestrial gamma radiation in the Sultanate of Oman.  

PubMed

The terrestrial gamma radiation level was determined throughout the Sultanate of Oman over a 3-y period. The dose rate at 1 m above the ground was measured at 512 locations using a compensated Geiger-Miller detector. The activity concentration of soil/rock samples, collected from 112 locations, was determined by gamma spectrometry. Dose rates calculated from the activity concentrations compared well with the measured values corrected for the cosmic ray contribution. Some of the highest terrestrial dose rates, up to 110 nGy h(-1), were measured in shales (Wadi Bani Awf, Saih Hatat, and the Huqf) and exposed basement granites (Jebal Jalan and the Mirbat peninsula). Two small hot spots were found where the maximum dose rate was 1,024 nGy h(-1). The average dose rate in the main population area of the Batinah is 38.5 nGy h(-1) (0.29 mSv y(-1)) and Muscat 44.9 nGy h(-1) (0.34 mSv y(-1)). The mean population weighted dose rate is 39.8 nGy h(-1) (0.30 mSv y(-1)). Most of Oman's surface rock is limestone, which is low in concentrations of radionuclides from the uranium and thorium series. Hence, the average dose rate is well below the world average of 0.45 mSv y(-1). PMID:12046760

Goddard, C C

2002-06-01

169

HEALTH HAZARDS FROM FISSION PRODUCTS AND FALLOUT. II. GAMMA RADIATION FROM NUCLEAR WEAPONS FALLOUT  

Microsoft Academic Search

Methods of estimating the gamma radiation from fallout and fission ; products are discussed. (Gamma spectra and 0.1 Mev energy intervals for 101 ; fissions were calculated for the following times after fission: 1. 2. 5. and 10 ; hours; years. Fifty energy groups of width 1.300 to 1.399 Mev were used, ; covering the range 0.0 to 5.0 Mev.

Bjornerstedt

1960-01-01

170

Small scale local gamma ray features. [galactic radiation spectra  

NASA Technical Reports Server (NTRS)

In order to draw implications from nearby gamma-ray emission, the different ways that can be used to obtain an estimate of the amount of matter on each line of sight are investigated. It is shown that, within present uncertainties, the cosmic ray intensity inside molecular clouds within 1 kpc from the sun is the same as the cosmic ray intensity measured at the sun. In the last part, what can be learned from a comparison of far infrared and gamma-ray data is discussed.

Puget, J. L.; Ryter, C.; Serra, G.

1977-01-01

171

Gamma radiation induced degradation in PE-PP block copolymer  

SciTech Connect

In the present investigation, effect of gamma irradiation on the PP-PE block copolymer has been studied. The polymer has been subjected to gamma irradiation from 100 to 500 Mrad dosages. Characterization of the polymer using XRD and FTIR was done both before irradiation and after irradiation in each step. Effect of irradiation on the electrical properties of the material has also been studied. FTIR study shows that the sample loses C - C stretching mode of vibration but gains C=C stretching mode of vibration after irradiation. Present investigation clearly indicates that though the electrical conductivity increases in the material, it undergoes degradation and shows brittleness due to irradiation.

Ravi, H. R.; Sreepad, H. R.; Ahmed, Khaleel; Govindaiah, T. N. [P.G. Department of Physics, Government College (Autonomous), Mandya - 571401, Karnataka State (India)

2012-06-05

172

Dynamics of the changes in the tissular levels of cyclic AMP after cobalt-60 gamma-irradiation.  

PubMed

The total amounts of cyclic AMP in liver, brain and intestinal mucosa have been measured in rats, at constant intervals, up to 18 days after whole body exposure to either a unique moderate dose (500 rd) or a unique lethal dose (750 rd) of cobalt-60 gamma-radiation. This radiation, even in a lethal dose, was found to induce no significant changes in the hepatic levels of cAMP. In contrast, an abrupt short-lasting increase in the levels of cAMP was observed in brain and intestinal mucosa after a 500-rd-irradiation, and a progressive long-lasting increase in its levels in the intestinal mucosa and, especially, in the brain was found after a 750-rd-irradiation. It is concluded that these organs contain different cAMP systems, which would explain, at least in part, their dissimilar responses to the ionizing rays. PMID:3869

P?usescu, E; Popescu, M; P?un, C; Teodosiu, T

1976-02-01

173

SAS-2 observations of the high energy gamma radiation from the Vela region  

NASA Technical Reports Server (NTRS)

Data from a scan of the galactic plane by the SAS-B high energy gamma ray experiment in the region 250 deg smaller than 12 smaller than 290 deg show a statistically significant excess over the general radiation from the galactic plane for gamma radiation of energy larger than 100 MeV. If the enhanced gamma radiation results from interactions of cosmic rays with galactic matter, as the energy spectrum suggests, it seems reasonable to associate the enhancement with large scale galactic features, such as spiral arm segments in that direction, or with the region surrounding the Vela supernova remnant with which PSR 0833-45 is associated. If the excess is attributed to cosmic rays released from the supernova interacting with the interstellar matter in that region, than on the order of 3 x 10 to the 50th power ergs would have been released by that supernova in the form of cosmic rays.

Thompson, D. J.; Bignami, G. F.; Fichtel, C. E.; Kniffen, D. A.

1974-01-01

174

Patient doses in {gamma}-intracoronary radiotherapy: The Radiation Burden Assessment Study  

SciTech Connect

Purpose: To determine accurately the radiation burden of both patients and staff from intracoronary radiotherapy (IRT) with {sup 192}Ir and to investigate the importance of IRT in the patient dose compared with interventional X-rays. Methods and materials: The Radiation Burden Assessment Study (RABAS) population consisted of 9 patients undergoing {gamma}-IRT after percutaneous transluminal coronary angioplasty and 14 patients undergoing percutaneous transluminal coronary angioplasty only as the control group. For each patient, the dose to the organs and tissues from the internal and external exposure was determined in detail by Monte Carlo N-particle simulations. Patient skin dose measurements with thermoluminescence dosimeters served as verification. Staff dosimetry was performed with electronic dosimeters, thermoluminescence dosimeters, and double film badge dosimetry. Results: With respect to the patient dose from IRT, the critical organs are the thymus (58 mGy), lungs (31 mGy), and esophagus (27 mGy). The mean effective dose from IRT was 8 mSv. The effective dose values from interventional X-rays showed a broad range (2-28 mSv), with mean values of 8 mSv for the IRT patients and 13 mSv for the control group. The mean dose received by the radiotherapist from IRT was 4 {mu}Sv/treatment. The doses to the other staff members were completely negligible. Conclusion: Our results have shown that the patient and personnel doses in {gamma}-IRT remain at an acceptable level. The patient dose from IRT was within the variations in dose from the accompanying interventional X-rays.

Thierens, Hubert [Department of Medical Physics and Radiation Protection, Ghent University, Ghent (Belgium)]. E-mail: hubert.thierens@Ughent.be; Reynaert, Nick [Department of Medical Physics and Radiation Protection, Ghent University, Ghent (Belgium); Bacher, Klaus [Department of Medical Physics and Radiation Protection, Ghent University, Ghent (Belgium); Eijkeren, Marc van [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium); Taeymans, Yves [Department of Cardiology, Ghent University Hospital, Ghent (Belgium)

2004-10-01

175

Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system  

DOEpatents

A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

2013-02-12

176

[Gamma scattering in condensed matter with high intensity Moessbauer radiation  

SciTech Connect

This report discusses: quasielastic scattering studies on glycerol; gamma-ray scattering from alkali halides; lattice dynamics in metals; Moessbauer neutron scattering, x-ray diffraction, and macroscopic studies of high {Tc} superconductors containing tungsten; NiAl scattering studies; and atomic interference factors and nuclear Casimir effect.

Not Available

1992-06-01

177

(Gamma scattering in condensed matter with high intensity Moessbauer radiation)  

SciTech Connect

This report discusses: quasielastic scattering studies on glycerol; gamma-ray scattering from alkali halides; lattice dynamics in metals; Moessbauer neutron scattering, x-ray diffraction, and macroscopic studies of high {Tc} superconductors containing tungsten; NiAl scattering studies; and atomic interference factors and nuclear Casimir effect.

Not Available

1992-01-01

178

The double radiative $\\bar{B}\\to X_s\\gamma \\gamma$ decay at $O(\\alpha_{s})$ in QCD  

E-print Network

In these proceedings, we briefly review the individual interference contribution of the electromagnetic dipole operator $\\mathcal{O}_{7}$ to the double differential decay width $d\\Gamma_{77}/(ds_1\\, ds_2)$ for the process $\\bar{B} \\to X_s \\gamma \\gamma$ at $O(\\alpha_s)$ in QCD, which is based on our previous work. We define two kinematical variables $s_1$ and $s_2$ as $s_i=(p_b - q_i)^2/m_b^2$, where $p_b$, $q_1$, $q_2$ are the momenta of b-quark and two photons. While the (renormalized) virtual corrections are worked out exactly for a certain range of $s_1$ and $s_2$, we retained in the gluon bremsstrahlung process only the leading power w.r.t. the (normalized) hadronic mass $s_3=(p_b-q_1-q_2)^2/m_b^2$ in the underlying triple differential decay width $d\\Gamma_{77}/(ds_1 ds_2 ds_3)$. We found that the double differential decay width, based on this approximation, is free of infrared- and collinear singularities when summing up the virtual- and real-radiation corrections, while this was not the case when keepi...

Kokulu, Ahmet

2014-01-01

179

A system for low-level the cosmogenic 22 Na radionuclide measurement by gamma–gamma coincidence method using BGO detectors  

Microsoft Academic Search

In this study, a gamma–gamma coincidence spectrometry was developed and examined for environmental low-level cosmogenic 22Na monitoring purposes. The spectrometry consists of two bismuth germanate scintillators (BGO) and XIA LLC Digital Gamma Finder\\u000a (DGF)\\/Pixie-4 software and card package. The developed spectrometry was optimized according to the considerations of output\\u000a count rate and gamma peak energy resolution. This spectrometry provides a

Weihua ZhangJing; Jing Yi; Pawel Mekarski; Ian Hoffman; Kurt Ungar; Ari-Pekka Leppänen

2011-01-01

180

Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes  

Microsoft Academic Search

The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using

T. P. Puck; R. Johnson; C. A. Waldren; H. Morse

1993-01-01

181

The high energy gamma-ray background and the interstellar radiation field  

NASA Astrophysics Data System (ADS)

This thesis provides an independent estimate of the high latitude (! b! > 20°) contribution to the E > 30 MeV gamma-ray background from Galactic nucleon-nucleon, electron bremsstrahlung and inverse Compton processes. In particular, the inverse Compton contribution has been estimated for different cosmic ray electron distributions and after factoring in the anisotropy in the interstellar radiation field and the anisotropic Klein-Nishina scattering cross section. A model for the interstellar radiation field from 0.1 ?m to 1000 ?m is also presented to fit the intensities observed by recent satellite experiments, especially the DIRBE and FIRAS instruments on COBE. I find that the emission from the inverse Compton process when the anisotropy in the radiation field is included can be higher by up to 50% when compared to estimates that adopt an isotropic radiation field. Simulated inverse Compton maps with a cosmic ray electron distribution represented by a ``pill box'' extending up to a distance of 5 kpc above the Galactic plane provide better fits to the EGRET intensity maps suggesting that the cosmic ray halo may be larger than previously thought. With this distribution, I find that the net contribution from the IC process to the gamma-ray background can be as high as 20% at high Galactic latitudes. Fitting for the Galactic components of gamma-ray emission confirms the existence of an isotropic component with an intensity that can be represented by the form 27.7 × E(MeV)-2.16 photons m-2 s-1 sr -1 MeV-1, in excellent agreement with previous estimates. The spectrum of the isotropic component further argues strongly in favor of unresolved gamma-ray blazars being the source of this emission. Introduction of an anisotropic component improves the quality of the fits. However, this component, which could potentially arise from the dark matter in the Galactic halo, is not well characterized by a single power law which might be associated with any single dark matter candidate. It has an intensity of about a third of the isotropic background above E > 100 MeV-1, at the level of 3 × 10-2 photons m-2 s-1 sr-1 . The best fit power law spectrum to this component has a photon index of -1.7. Based on the intensity and spectrum of the anisotropic component I derive upper limits of 109Msolar for the mass of cold, baryonic gas within the solar circle and a primordial black hole number density limit of 7 × 107 pc -3 which is more than an order of magnitude smaller than previous limits. If the spectrum of the anisotropic component is indeed confirmed to have an index of -1.7, it appears more likely that the signal arises in unresolved Galactic sources such as pulsars.

Chary, Ranga-Ram

182

Chronic exposure to gamma radiation of wild populations of meadow voles (Microtus pennsylvanicus).  

PubMed

Free-ranging, wild meadow voles (Microtus pennsylvanicus) were exposed to gamma radiation from a (137)Cs irradiator in a series of experiments conducted on six 1-ha meadows within a mixed deciduous forest in Manitoba, Canada. Over a period of 1-1.5 years in each of three experiments, vole populations were monitored with capture-mark-release techniques at nominal exposure rates of 200x, 9000x and 40,000x background. No effects on population or individual characteristics were detected up to the highest exposure rate (81 mGy/d). At this level, third generation voles were monitored up to a lifetime dose of about 5.7 Gy, at a measured dose rate of 44 mGy/d. Smaller numbers of overwintered animals survived and reproduced normally at doses up to 10 Gy. These results are discussed in terms of low-LET, external chronic radiation effects on rodents in the laboratory and the field, relative to current views on appropriate benchmarks for the protection of biota. PMID:15193792

Mihok, Steve

2004-01-01

183

Gamma radiation and photospheric white-light flare continuum  

NASA Technical Reports Server (NTRS)

It is noted that recent gamma-ray observations of solar flares have provided a better means for estimating the heating of the solar atmosphere by energetic protons. This type of heating has been suggested as the explanation of the continuum emission of the white-light flare. The effects on the photosphere of high-energy particles capable of producing the intense gamma-ray emission observed in the flare of July 11, 1978, are analyzed. A simple energy-balance argument is used, and hydrogen ionization is taken into account. It is found that energy deposition increases with height for the inferred proton spectra and is not strongly dependent upon the assumed angle of incidence. At the top of the photosphere, the computed energy inputs fall in the range 10-100 ergs/cu cm-s.

Hudson, H. S.; Dwivedi, B. N.

1982-01-01

184

Effect of cross-linkage by gamma radiation in heavy doses to low wear polyethylene in total hip prostheses  

Microsoft Academic Search

Wear, frictional torque and creep deformity of UHMWPE sockets crosslinked by gamma radiation of 100, 500 and 1000 Mrad in combination with 28 mm alumina heads, were measured using a hip simulator (under constant load 250 kgf with lubrication of saline solution). Hardness and hydrophilic increased and creep deformity decreased as a result of gamma radiation. The initial wear (decrement

H. Oonishi; H. Ishimaru; A. Kato

1996-01-01

185

Seabuckthron (Hippophae rhamnoides L.) leaf extract ameliorates the gamma radiation mediated DNA damage and hepatic alterations.  

PubMed

In vitro assessment showed that H. rhamnoides (HrLE) extract possessed free radical scavenging activities and can protect gamma (gamma) radiation induced supercoiled DNA damage. For in vivo study, Swiss albino mice were administered with HrLE (30 mg/kg body weight) for 15 consecutive days before exposing them to a single dose of 5 Gy of beta radiation. HrLE significantly prevented the radiation induced genomic DNA damage indicated as a significant reduction in the comet parameters. The lipid peroxidation, liver function enzymes, expression of phosphorylated NFkappaB (p65) and IkappaBalpha increased whereas the endogenous antioxidants diminished upon radiation exposure compared to control. Pretreatment of HrLE extract ameliorated these changes. Based on the present results it can be concluded that H. rhamnoides possess a potential preventive element in planned and accidental nuclear exposures. PMID:25345244

Khan, Amitava; Manna, Krishnendu; Chinchubose; Das, Dipesh Kr; Sinha, Mahuya; Kesh, Swaraj Bandhu; Das, Ujjal; Dey, Rakhi Sharma; Banerji, Asoke; Dey, Sanjit

2014-10-01

186

Sources of Cosmic Rays and Galactic Diffuse Gamma Radiation  

E-print Network

The diffuse galactic gamma-ray spectrum measured by the EGRET experiment \\citep{Hunter:1997} are interpreted within a scenario in which cosmic rays (CRs) are injected by three different kind of sources, (i) supernovae (SN) which explode into the interstellar medium (ISM), (ii) Red Supergiants (RSG), and (iii) Wolf-Rayet stars (WR), where the two latter explode into their pre-SN winds (Biermann et al. 2001; Sina et al. 2001).

Sabrina Casanova; Peter L. Biermann; Ralph Engel; Athina Meli; Ralf Ulrich

2004-03-29

187

Gamma radiation dosimetry in mega rad range using sugar solution  

Microsoft Academic Search

The formation of Malonaldehyde under gamma irradiation of solid sucrose and aqueous sucrose, fructose and arabinose solutions has been studied in the Mega rad range. Malonaldehyde (MA) concentration was estimated spectrophotometrically after complexing with 2-Thio-barbituric acid. The effect of free radical scavengers (KI and N2O) on the yield of Ma was investigated. Of the systems studied a 5% aqueous sucrose

R. Venkataramani; Sudershan K. Mehta; S. D. Soman

1976-01-01

188

Radioactivity of building materials and the gamma radiation in dwellings.  

PubMed

Measurements of the radioactivity in some common building materials in Norway are reported, together with calculations of the gamma-ray exposure from walls of different materials. Model rooms are used in calculations of the mean exposure inside concrete, brick and light-weight expanded clay aggregate buildings. These calculations give very good agreement with previous experimental results. The radiological implications of using building materials with high concentrations of radioactivity are also discussed. PMID:515178

Stranden, E

1979-09-01

189

Poly (DADMAC) encapsulation in PES microcapsules utilizing gamma radiation  

NASA Astrophysics Data System (ADS)

In this communication, a method for encapsulation of a polymeric resin using radiation technology is reported. The quaternary ammonium resin, polydiallyldimethylammonium chloride (PDADMAC) was incorporated in the core of a preformed hollow polyethersulfone microcapsule, using radiation technology, for the extraction of anions from aqueous solutions. The idea was to introduce the monomer into the porous microcapsules and initiate polymerization by radiation to trap the polymer formed inside the capsule. The resultant capsule was able to take up and exchange some anions (F -, Cl -, Br -, NO 32- and SO 42-) at relatively low concentrations.

Francis, Sanju; Varshney, Lalit; Tirumalesh, Keesari; Sabharwal, Sunil

2009-01-01

190

Determination of ¹N gamma radiation fields at BWR nuclear power stations  

Microsoft Academic Search

Measurements of environmental gamma radiation fields produced by ¹N in components above the floor in the turbine buildings of two large BWR power plants were carried out in April 1975, using pressurized argon ionization chambers and NaI(Tl) and Ge(Li) spectrometers. Both turbine buildings are heavily side-shielded, so that the bulk of the radiation outside the buildings is skyshine. The shapes

W. M. Lowder; P. D. Raft; G. deP Burke

1976-01-01

191

Gamma rays from the B10 5.16 MeV level near the (d, n) threshold  

Microsoft Academic Search

The gamma -ray threshold method was used to establish conclusively that ; the gamma -ray emitting state near 5.2 Mev in B¹° is the level at 5.159 ; plus or minus 0.007 Mev associated with the 0.99Mev neutron threshold in the Be\\/; sup 9\\/(d,n)B¹° reaction. The partial gamma width of this state was ; determined to be GAMMA gamma ---(0.7

E. K. Warburton; L. F. Jr. Chase

1962-01-01

192

Very high energy gamma-ray absorption via localized diffuse radiation fields  

NASA Astrophysics Data System (ADS)

When Very High Energy (VHE) gamma-rays (E>100 GeV) transverse low energy photon fields, the production of electron-positron pairs leads to the attenuation of the intrinsic gamma-ray flux. This phenomena is well know for VHE radiation from extragalactic sources, like e.g. blazars, interacting with the cosmic infrared background. In this contribution the absorption of VHE gamma-rays due to the interaction with localized low energy radiation fields, e.g. the Milky Way diffuse radiation field, cluster radiation fields and radiation fields in voids and filaments is discussed. While the photon field densities of these inhomogeneous radiation fields can be several orders of magnitude higher compared to the homogeneous background, the distances are in general shorter leading to an overall smaller effect. On the other hand, the detection of such an attenuation could be used to study the IR emission on different scales, measure the distance of galactic sources, or investigate particle physics phenomena beyond the standard model. It is investigated how forthcoming imaging air Cherenkov telescopes, like CTA, and wide angle Cherenkov arrays, like HiSCORE, with their improved sensitivities up to several hundred TeV will measure this absorption feature.

Maurer, Andreas; Becerra-Gonzalez, Josefa; Raue, Martin; Horns, Dieter

2012-12-01

193

Estimation of 237U Level Density and Radiative Strength Functions from the (n,?) Reaction  

NASA Astrophysics Data System (ADS)

Intensity distribution of the primary ?-transitions following resonance neutron capture in 236U about the mean value was approximated in different energy intervals of these quanta and neutrons. Extrapolation of the obtained functions to zero registration threshold of ?-transitions allowed independent estimation of the expected level number of both parities for spin values J = 1/2, 3/2 and sum of radiative widths for both electric and magnetic gamma-transitions to levels with excitation energy up to ~2.3 MeV.

Sukhovoj, Anatoly M.; Khitrov, Valery A.; Maslov, Vladimir M.

2009-01-01

194

Radiation effect on silicon transistors in mixed neutrons-gamma environment  

NASA Astrophysics Data System (ADS)

The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors. The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation.

Assaf, J.; Shweikani, R.; Ghazi, N.

2014-10-01

195

Orbital Observatory GLAST - New Step in the Study of Cosmic Gamma Radiation: Mission Overview  

NASA Technical Reports Server (NTRS)

This viewgraph presentation is a overview of the Gamma-ray Large Area Space Telescope (GLAST), now named Fermi Space Telescope. The new telescope is scheduled for launch in the middle of 2008. It contains the high energy gamma-ray telescope LAT (Large Area Telescope) and the GMB (GLAST Burst Monitor). The science objectives of GLAST cover almost every area of high energy astrophysics, including Active Galactic Nuclei (AGN), including Extragalactic background light (EBL), Gamma-ray bursts (GRB), Pulsars, Diffuse gamma-radiation, EGRET unidentified sources, Solar physics, Origin of Cosmic Rays and, Dark Matter and New Physics. Also included in this overview is a discussion of the preparation to the analysis of the science data.

Moiseev, Alexander

2008-01-01

196

The production and composition of rat sebum is unaffected by 3 Gy gamma radiation  

PubMed Central

Purpose The aim of this work was to use metabolomics to evaluate sebum as a source of biomarkers for gamma-radiation exposure in the rat, and potentially in man. Proof of concept of radiation metabolomics was previously demonstrated in both mouse and rat urine, from the radiation dose- and time-dependent excretion of a set of urinary biomarkers. Materials and methods Rats were gamma-irradiated (3 Gy) or sham irradiated and groups of rats were euthanised at 1 h or 24 h post-irradiation. Sebum was collected by multiple washings of the carcasses with acetone. Nonpolar lipids were extracted, methylated, separated and quantitated using gas chromatography-mass spectrometry (GCMS). Metabolomic analysis of the GCMS data was performed using both orthogonal projection to latent structures-discriminant analysis and random forests machine learning algorithm. Results Irradiation did not alter sebum production. A total of 35 lipids were identified in rat sebum, 29 fatty acids, five fatty aldehydes, and cholesterol. Metabolomics showed that three fatty acids, palmitic, 2-hydroxypalmitic, and stearic acids were potential biomarkers. Sebaceous palmitic acid was marginally statistically significantly elevated (7.5–8.4%) at 24 h post-irradiation. Conclusions Rat sebaceous gland appears refractory to 3 Gy gamma-irradiation. Unfortunately, collection of sebum shortly after gamma-irradiation is unlikely to form the basis of high-throughput non-invasive radiation biodosimetry in man. PMID:21158499

Lanz, Christian; Ledermann, Monika; Slavik, Josef; Idle, Jeffrey R.

2013-01-01

197

MICRONUCLEI IN BINUCLEATED LYMPHOCYTES OF MICE FOLLOWING EXPOSURE TO GAMMA RADIATION  

EPA Science Inventory

Experiments were designed to investigate the induction of micronuclei (MN) in mouse peripheral blood lymphocytes (PBLs) after in vitro or in vivo exposure to 60Co gamma radiation. or the in vitro experiments, 4 ml of blood from male C57BL/6J mice were either irradiated in 6 ml Fa...

198

Effect of Gamma and UV Radiation on Properties of EPDM\\/GTR\\/HDPE Blends  

Microsoft Academic Search

Ethylene propylene dine monomer (EPDM) was blended with both ground tire rubber (GTR) and high-density polyethylene (HDPE) prepared at different ratios and then exposed to gamma and ultraviolet radiations. The mechanical, physical, and thermal properties were investigated with respect to the kind of irradiation and blend compositions. A scanning electron microscope was also used to examine the morphology of the

M. M. Abou Zeid; S. T. Rabie; A. A. Nada; A. M. Khalil; R. H. Hilal

2008-01-01

199

Luffa fibers and gamma radiation as improvement tools of polymer Gonzalo Martnez-Barrera a,  

E-print Network

, silica fume, silica sand; the last one the most used due to size distribution, ranging from 0.6 to 4.0 mmLuffa fibers and gamma radiation as improvement tools of polymer concrete Gonzalo Martínez-5017, USA h i g h l i g h t s Polymer concrete with silicious sand, unsaturated polyester resin and luffa

North Texas, University of

200

An Analysis of a Spreader Bar Crane Mounted Gamma-Ray Radiation Detection System  

E-print Network

. This is inadequate to protect our country. This research involved the building of a gamma-ray radiation detection system used for cargo scanning. The system was mounted on a spreader bar crane (SBC) at the Port of Tacoma (PoT) and the applicability and capabilities...

Grypp, Matthew D

2013-04-08

201

Response of shortgrass plains vegetation to gamma radiation. I. Chronic irradiation  

Microsoft Academic Search

Native shortgrass plains vegetation was exposed to chronic gamma ; radiation with exposure rates varying from 0.01 to 650 R\\/hr starting in April ; 1969. The dominant species in the plant community was Bouteloua gracilis (blue ; grama). Density and frequency were recorded and these data were converted into ; community indices of coefficient of community (CC) and diversity (D).

L. Jr. Fraley; F. W. Whicker

1973-01-01

202

Gamma radiation effects on physical properties of parchment documents: Assessment of Dmax  

NASA Astrophysics Data System (ADS)

Parchments are important documents that give testimony for History; therefore these materials should be respected and preserved. Considering incremental biodeterioration problems that have to be faced daily, the Archive of the University of Coimbra (AUC) is involved in different scientific projects in order to evaluate and determine new methods for document decontamination and preservation. The aim of this study was to evaluate gamma radiation effects on the colour and texture of the AUC parchment documents. The assessment of these effects was used to estimate the maximum gamma radiation dose (Dmax) that could guarantee parchment documents' decontamination treatment, without significant alteration of their physical properties. Parchment samples were exposed to gamma radiation doses ranging from 10 to 30 kGy. The texture and colour of samples were assessed before and after the irradiation procedure, using a texture analyser and an electronic colorimeter. Hardness and springiness were determined based on texture spectra. Lightness (L*), Chroma (C), greenness vs. redness (a*) and yellowness vs. blueness (b*) values were obtained from colorimetric measures. Results indicate no significant effects of gamma radiation on the texture and colour of parchment for the studied doses.

Nunes, Inês; Mesquita, Nuno; Cabo Verde, Sandra; João Trigo, Maria; Ferreira, Armando; Manuela Carolino, Maria; Portugal, António; Luísa Botelho, Maria

2012-12-01

203

Radiation measurement above the lunar surface by Kaguya gamma-ray spectrometer  

NASA Astrophysics Data System (ADS)

The lunar surface is filled with various ionizing radiations such as high energy galactic particles, albedo particles and secondary radiations of neutrons, gamma rays and other elementary particles. A high-resolution Kaguya Gamma-Ray Spectrometer (KGRS) was carried on the Japan’s lunar explorer SELENE (Kaguya), the largest lunar orbiter since the Apollo missions. The KGRS instrument employed, for the first time in lunar exploration, a high-purity Ge crystal to increase the identification capability of elemental gamma-ray lines. The Ge detector is surrounded by BGO and plastic counters as for anticoincidence shields. The KGRS measured gamma rays in the energy range from 200 keV to 13 MeV with high precision to determine the chemical composition of the lunar surface. It provided data on the abundance of major elements over the entire lunar surface. In addition to the gamma-ray observation by the KGRS, it successfully measured the global distribution of fast neutrons. In the energy spectra of gamma-rays observed by the KGRS, several saw-tooth- peaks of Ge are included, which are formed by the collision interaction of lunar fast neutrons with Ge atoms in the Ge crystal. With these saw-tooth-peaks analysis, global distribution of neutrons emitted from the lunara surface was successfully created, which was compared with the previous results obtained by Lunar Prospector neutron maps. Another anticoincidence counter, the plastic counter with 5 mm thickness, was used to veto radiation events mostly generated by charged particles. A single photomultiplier serves to count scintillation light from the plastic scintillation counter. The global map of counting rates observed by the plastic counter was also created, implying that the radiation counting rate implies the geological distribution, in spite that the plastic counter mostly measures high energy charged particles and energetic neutrons. These results are presented and discussed.

Hasebe, Nobuyuki; Nagaoka, Hiroshi; Kusano, Hiroki; Hareyama, Matoko; Ideguchi, Yusuke; Shimizu, Sota; Shibamura, Eido

204

Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System  

E-print Network

An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. T...

Bromberger, B; Brandis, M; Dangendorf, V; Goldberg, M B; Kaufmann, F; Mor, I; Nolte, R; Schmiedel, M; Tittelmeier, K; Vartsky, D; Wershofen, H

2012-01-01

205

Radiation levels on empty cylinders containing heel material  

SciTech Connect

Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

Shockley, C.W. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31

206

Degradation in Thermal Properties and Morphology of Polyetheretherketone-Alumina Composites Exposed to Gamma Radiation  

NASA Astrophysics Data System (ADS)

Sheets of polyetheretherketone (PEEK) and PEEK-alumina composites with micron-sized alumina powder with 5, 10, 15, 20, and 25% by weight were fabricated, irradiated with gamma rays up to 10 MGy and the degradation in their thermal properties and morphology were evaluated. The radicals generated during irradiation get stabilized by chain scission and crosslinking. Chain scission is predominant on the surface and crosslinking is predominant in the bulk of the samples. Owing to radiation damage, the glass transition temperature, T g increased for pure PEEK from 136 to 140.5 °C, whereas the shift in T g for the composites decreased with increase in alumina content and for PEEK-25% alumina, the change in T g was insignificant, as alumina acts as an excitation energy sink and reduces the crosslinking density, which in turn decreased the shift in T g towards higher temperature. Similarly, the melting temperature, T m and enthalpy of melting, ? H m of PEEK and PEEK-alumina composites decreased on account of radiation owing to the restriction of chain mobility and disordering of structures caused by crosslinks. The decrease in T m and ? H m was more pronounced in pure PEEK and the extent of decrease in T m and ? H m was less for composites. SEM images revealed the formation of micro-cracks and micro-pores in PEEK due to radiation. The SEM image of irradiated PEEK-alumina (25%) composite showed negligible micro-cracks and micro-pores, because of the reinforcing effect of high alumina content in the PEEK matrix which helps in reducing the degradation in the properties of the polymer. Though alumina reduces the degradation of the polymer matrix during irradiation, an optimum level of ceramic fillers only have to be loaded to the polymer to avoid the reduction in toughness.

Lawrence, Falix; Mishra, Satyabrata; Mallika, C.; Kamachi Mudali, U.; Natarajan, R.; Ponraju, D.; Seshadri, S. K.; Sampath Kumar, T. S.

2012-07-01

207

Identification and control of spacecraft radiation sources of interference to X-ray and gamma-ray experiments  

NASA Technical Reports Server (NTRS)

Apollo 15 and 16 will carry instruments for the purpose of measuring X-ray and gamma ray fluxes from the lunar surface and in cis-lunar space. The intensity levels expected are low over most of the energy range of interest, requiring that background contributions be minimized. The radiation sources on Apollo determined and their interference with these instruments evaluated. The results were used as a basis for dealing with this problem and for recommendations applicable to future manned and unmanned missions.

Metzger, A. E.; Trombka, J. I.

1972-01-01

208

Response of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), eggs to gamma radiation  

NASA Astrophysics Data System (ADS)

As insects increase in radiotolerance as they develop and usually several developmental stages of the pest may be present in the fresh shipped commodity, it is important to know the radiation susceptibility of the stages of the target insect before the establishment of ionizing radiation quarantine treatments. This study was performed to determine the radiotolerance of eggs of the oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), to gamma radiation. This species is considered as one of the most serious worldwide pests for temperate fruits, especially peaches. Eggs (12 h old) were exposed to 0 (control), 25, 35, 50, 75, 100, 125 and 150 Gy of gamma radiation. Surviving larvae were allowed to feed on an artificial diet. Three days after irradiation, it was verified that larvae's cephalic capsules were significantly affected by gamma radiation, and the estimated mean LD 90 and LD 99 were 66.3 Gy and 125.8 Gy, respectively. Oriental fruit moth eggs revealed to be quite radiosensitive and very low doses as 50 Gy were sufficient to disrupt G. molesta embryogenesis. At 25 Gy, only male adults originated from the surviving larvae and, after mating with untreated fertile females, shown to be sterile.

Silva, W. D.; Arthur, V.; Mastrangelo, T.

2010-10-01

209

Radiation levels in the SSC interaction regions  

SciTech Connect

The radiation environment in a typical SSC detector has been evaluated using the best available particle production models coupled with Monte Carlo simulations of hadronic and electromagnetic cascades. The problems studied include direct charged particle dose, dose inside a calorimeter from the cascades produced by incident photons and hadrons, the flux of neutrons and photons backscattered from the calorimeter into a central cavity, and neutron flux in the calorimeter. The luminosity lifetime at the SSC is dominated by collision losses in the interaction regions, where the luminosity is equivalent to losing an entire full-energy proton beam into the apparatus every six days. The result of an average p-p collision can be described quite simply. The mean charged multiplicity is about 110, and the particles are distributed nearly uniformly in pseudorapidity ({eta}) over all the angles of interest. The transverse momentum distribution is independent of angle, and for our purposes may be written as p{perpendicular}exp(-p{perpendicular}/{beta}). The mean value of p{perpendicular} may be as high as 0.6 GeV/c. Most of the radiation is produced by the very abundant low-p{perpendicular} particles. The dose or neutron fluence produced by individual particles in this energy region are simulated over a wide variety of conditions, and several measurements serve to confirm the simulation results. In general, the response (a dose, fluence, the number of backscattered neutrons, etc.) for an incident particle of momentum p can be parameterized in the form Np{sup {alpha}}, where 0.5 < {alpha}< 1.0. The authors believe most of their results to be accurate to within a factor of two or three, sufficiently precise to serve as the basis for detailed designs.

Groom, D.E. [ed.

1988-06-10

210

Development of a Neutron\\/gamma Ray Radiation Monitor  

Microsoft Academic Search

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the

Kofi John Korsah

1983-01-01

211

Resonant level lifetime in GaAs-AlAs double-barrier structures including. Gamma. - X mixing  

SciTech Connect

A quantitative model for calculation of the lifetime of quasibound states, including the {Gamma}-{ital X} transfer, in a AlAs-GaAs-AlAs double-barrier structure is presented. When device is designed that a {Gamma}-like energy level approaches to an {ital X}-like energy level, anticrossing of the {Gamma}-{ital X} transition occurs and the lifetime of the state can be several orders larger than that of a pure {Gamma} system.

Zheng, T.F. (Department of Natural Science, Manatee College, Bradenton, Florida 34207 (USA)); Cai, W.; Hu, P. (Department of Physics, City College of the City University of New York, New York, New York 10031 (USA)); Lax, M. (Department of Physics, City College of the City University of New York, New York, New York 10031 (USA) AT T Bell Laboratories, Murray Hill, New Jersey 07974 (USA)); Shum, K.; Alfano, R.R. (Institute for Ultrafast Spectroscopy and Lasers, Departments of Electrical Engineering and Physics, City College of the City University of New York, New York, New York 10031 (USA))

1991-06-15

212

A Monte Carlo Calculation of Muon Flux at Ground Level from Primary Cosmic Gamma Rays  

SciTech Connect

The Monte Carlo program FLUKA was used to calculate the number of muons reaching detection level in events initiated by primary cosmic gamma ray interactions in the atmosphere. The calculation was motivated by the desire to gauge the sensitivity of arrays like that of Project GRAND to primary gamma cosmic rays while measuring single muons at detection level. Because direct gamma pair production is not a significant source of muons, normally the presence of muons is not considered as a signal for gamma rays. However, due to their non-negligible cross section for hadron production, high-energy gamma rays can initiate hadronic showers containing a large number of pions. These can decay producing secondary muons which then have a good chance of reaching detection level. The complete kinetic energy and space distribution of such muons can be predicted by simulating in detail the whole process by means of Monte Carlo techniques. However, the code used must be capable of handling both hadron-nucleus and photon-nucleus interactions. Unlike most available Monte Carlo particle transport programs, such interactions are implemented in FLUKA, up to several tens of TeV, based on Dual Parton and Vector Meson Dominance models. The FLUKA capability to describe hadronic cascades generated in the atmosphere by primary cosmic hadrons has already been shown in several studies. In the present paper, the investigation has been extended to primary gamma rays. The number of muons per photon is presented as a function of the primary energy in the region between 3 GeV and 10 TeV. As the energy of primary photons rises, their flux falls, whereas the number of muons per gamma rises. Combining these two effects, it can be predicted that gamma ray energies in the 30 GeV region produce the most muons at detection level. The radial and kinetic energy distributions of the muons are also presented.

Fasso, Alberto

1999-08-27

213

Evaluation of fungal burden and aflatoxin presence in packed medicinal plants treated by gamma radiation.  

PubMed

This study was developed to evaluate the fungal burden, toxigenic molds, and mycotoxin contamination and to verify the effects of gamma radiation in four kinds of medicinal plants stored before and after 30 days of irradiation treatment. Eighty samples of medicinal plants (Peumus boldus, Camellia sinensis, Maytenus ilicifolia, and Cassia angustifolia) purchased from drugstores, wholesale, and open-air markets in São Paulo city, Brazil, were analyzed. The samples were treated using a (60)Co gamma ray source (Gammacell) with doses of 5 and 10 kGy. Nonirradiated samples were used as controls of fungal isolates. For enumeration of fungi on medicinal plants, serial dilutions of the samples were plated in duplicate onto dichloran 18% glycerol agar. The control samples revealed a high burden of molds, including toxigenic fungi. The process of gamma radiation was effective in reducing the number of CFU per gram in all irradiated samples of medicinal plants after 30 days of storage, using a dose of 10 kGy and maintaining samples in a protective package. No aflatoxins were detected. Gamma radiation treatment can be used as an effective method for preventing fungal deterioration of medicinal plants subject to long-term storage. PMID:20501045

Aquino, Simone; Gonçalez, Edlayne; Rossi, Maria Helena; Nogueira, Juliana Hellmeister de Campos; Reis, Tatiana Alves Dos; Corrêa, Benedito

2010-05-01

214

Hormetic effects of gamma radiation on the stress axis of natural populations of meadow voles (Microtus pennsylvanicus).  

PubMed

We tested the hypothesis that low doses of gamma radiation have beneficial, hormetic effects on the stress axis (the hypothalamic-pituitary-adrenocortical axis) of free-ranging meadow vole populations (Microtus pennsylvanicus). Voles were exposed to chronic gamma radiation from a 137Cs field irradiator. In isolated populations, voles received one of three treatments over a four-year period: Controls (0.19-0.42 microGy/h--levels that were 2-5x above background levels [0.1 microGy/h] and live-trapped in all years--1982--1985), low doses (22.6 microGy/h--50-200x background, live-trapped from November 1982--April 1985), or high doses (3,840 microGy/h--40,000x background, live-trapped from November 1983--April 1985). Voles exposed to a low dose had levels of free and total corticosterone that were significantly higher than those in the control or high-dose groups. Differences in response to radiation between the sexes were apparent for maximum corticosterone-binding capacity, with females exposed to low doses having higher binding capacity than control or high-dose females, whereas males exposed to low doses had lower binding capacity than control or high-dose males. Low-dose voles had higher counts of neutrophils than either the controls or high-dose voles; hematocrit was greater in the controls than in irradiated voles. These results indicate that voles display a hormetic response to radiation, wherein low doses of an otherwise harmful agent produce a beneficial effect. The stimulation of the stress axis resulting in the increased secretion of glucocorticoids, which may protect against the excessive actions of the immune and inflammatory responses, may be a key mechanism producing this effect. PMID:15719993

Boonstra, Rudy; Manzon, Richard G; Mihok, Steve; Helson, Julie E

2005-02-01

215

Using Gamma-Radiation for Drug Releasing from MWNT Vehicle  

NASA Astrophysics Data System (ADS)

A drug delivery system via multi-walled carbon nanotube (MWNT) vehicle was synthesized in aqueous solution. MWNTs were first noncovalently functionalized with chitosan oligomers (CS) with a molecule weight of 4000-6000, making MWNTs water-soluble, and then a cancer ancillary drug tea polyphenols (TP) was conjugated mainly via the hydrogen bond between CS and TP molecules, making MWNTs efficient vehicle for drug delivering. The release of drug molecules can be realized by pH variation and ?-radiation, leading to new methods for controlling drug release from carbon nanotubes carrier. Due to the high penetrability of ?-rays, ?-radiation shows up new opportunities in controlled drug release, possibly facilitating the future cancer treatment in vivo.

Li, Jun; Sun, Hao; Dai, Yao-Dong

2010-03-01

216

Field-deployable gamma-radiation detectors for DHS use  

Microsoft Academic Search

Recently, the Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial off-the-shelf and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable

Sanjoy Mukhopadhyay

2007-01-01

217

Effects of high vs low-level radiation exposure  

SciTech Connect

In order to appreciate adequately the various possible effects of radiation, particularly from high-level vs low-level radiation exposure (HLRE, vs LLRE), it is necessary to understand the substantial differences between (a) exposure as used in exposure-incidence curves, which are always initially linear and without threshold, and (b) dose as used in dose-response curves, which always have a threshold, above which the function is curvilinear with increasing slope. The differences are discussed first in terms of generally familiar nonradiation situations involving dose vs exposure, and then specifically in terms of exposure to radiation, vs a dose of radiation. Examples are given of relevant biomedical findings illustrating that, while dose can be used with HLRE, it is inappropriate and misleading the LLRE where exposure is the conceptually correct measure of the amount of radiation involved.

Bond, V.P.

1983-01-01

218

Variations observed in environmental radiation at ground level.  

PubMed

To investigate and monitor environmental radiation at ground level, Physikalisch-Technische Bundesanstalt (PTB) has installed several dosemeters and particle detectors at the new Ambient Radiation Dosimetry Site. The separation of the total ambient dose equivalent rate H*10(env) of environmental radiation into the different contributions is achieved by comparing the data of different detectors: the muon detector MUDOS, a modified neutron dosemeter, proportional counters and ionisation chambers. The response of the latter two dosemeter systems to cosmic radiation was determined at the Cosmic Radiation Dosimetry Site on a lake near PTB. Besides the increase of the ambient dose equivalent rate during rainfall, variations owing to air pressure, solar activity and temperature changes in the upper atmosphere are observed. Without rain and solar effects, smooth variations of the cosmic component at ground level of +/-6.9 nSv h(-1) should be treated as naturally occurring variations during an entire year. PMID:15985498

Wissmann, F

2006-01-01

219

Effects of gamma radiation on Serratia marcescens; a comparison of effects of two different exposure rates  

E-print Network

EFFECTS OF GAMMA RADIATION ON SL'RNATIA MARCESCENS A COMPARISON OF EFFECTS OF TWO DIFFERENT EXPOSURE RATES A Thesis by CHRISTY ANNETTE MOORE Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements...) Christy A. Moore, B, S, Northwestern State College Directed by: Dr. . R. D. Neff The survival curves of gamma-irradiated pigmenting and non- pigmcnting stzains of 'srz'rztia. mancssosns were determiz. ed using exposure rates of 175R/minute and 23, 520...

Moore, Christy Annette

2012-06-07

220

Thermal, mechanical and ionic conductive behaviour of gamma-radiation induced PEO/PVDF(SIN)-LiClO4 polymer electrolyte system  

NASA Astrophysics Data System (ADS)

An effort has been made to modify the mechanical behaviour of our previously reported gel-type gamma-radiation crosslinked polyethylene oxide (PEO)-LiClO4 polymer electrolyte. A highly polar and gamma-radiation crosslinkable crystalline polymer, polyvinylidene fluoride (PVDF), was selected to blend with PEO and then subjected to gamma-irradiation in order to make an simultaneous interpenetrating network (SIN), which was used as a polymer host to impart stiffness to the plasticized system. Experimental results have shown that the presence of PVDF in the system, through gamma-radiation induced SIN formation, could not only give a rather high mechanical modulus of 107 Pa at ambient temperature, but also maintain the room temperature ionic conductivity at a high level (greater than 10-4 S/cm). DSC, DMA and conductivity measurement techniques were used to examine the effects of blending, gamma-irradiation and plasticization on the variations of glass transition and melting endotherm, on the appearance of high elastic plateau and on the temperature dependence of ionic conductivity. In addition, it was found that, in contrast with the unplasticized system, the ionic conductivity mechanism of this gel-type electrolyte seems to conform to the Arrhenius model, suggesting that, as a result of the high degree of plasticization, the polymer chains act mainly as the skeleton of the networks or polymer cages to immobilize the liquid electrolyte solution, whereas the ionic species migrate as if they were in a liquid medium.

Yongxian, Song; Shuyun, Wu; Xiabing, Jing; Jiazhen, Sun; Donglin, Chen

1997-05-01

221

Thermal, mechanical and ionic conductive behaviour of gamma-radiation induced PEO/PVDF(SIN)-LiClO 4 polymer electrolyte system  

NASA Astrophysics Data System (ADS)

An effort has been made to modify the mechanical behaviour of our previously reported gel-type gamma-radiation crosslinked polyethylene oxide (PEO)-LiClO 4 polymer electrolyte. A highly polar and gamma-radiation crosslinkable crystalline polymer, polyvinylidene fluoride (PVDF), was selected to blend with PEO and then subjected to gamma-irradiation in order to make an simultaneous interpenetrating network (SIN), which was used as a polymer host to impart stiffness to the plasticized system. Experimental results have shown that the presence of PVDF in the system, through gamma-radiation induced SIN formation, could not only give a rather high mechanical modulus of 10 7 Pa at ambient temperature, but also maintain the room temperature ionic conductivity at a high level (greater than 10 -4 S/cm). DSC, DMA and conductivity measurement techniques were used to examine the effects of blending, gamma-irradiation and plasticization on the variations of glass transition and melting endotherm, on the appearance of high elastic plateau and on the temperature dependence of ionic conductivity. In addition, it was found that, in contrast with the unplasticized system, the ionic conductivity mechanism of this gel-type electrolyte seems to conform to the Arrhenius model, suggesting that, as a result of the high degree of plasticization, the polymer chains act mainly as the skeleton of the networks or polymer cages to immobilize the liquid electrolyte solution, whereas the ionic species migrate as if they were in a liquid medium.

Song, Yongxian; Wu, Shuyun; Jing, Xiabing; Sun, Jiazhen; Chen, Donglin

222

Radiation-induced bystander effects in the Atlantic salmon (salmo salar L.) following mixed exposure to copper and aluminum combined with low-dose gamma radiation.  

PubMed

Very little is known about the combined effects of low doses of heavy metals and radiation. However, such "multiple stressor" exposure is the reality in the environment. In the work reported in this paper, fish were exposed to cobalt 60 gamma irradiation with or without copper or aluminum in the water. Doses of radiation ranged from 4 to 75 mGy delivered over 48 or 6 h. Copper doses ranged from 10 to 80 ?g/L for the same time period. The aluminum dose was 250 ?g/L. Gills and skin were removed from the fish after exposure and explanted in tissue culture flasks for investigation of bystander effects of the exposures using a stress signal reporter assay, which has been demonstrated to be a sensitive indicator of homeostatic perturbations in cells. The results show complex synergistic interactions of radiation and copper. Gills on the whole produce more toxic bystander signals than skin, but the additivity scores show highly variable results which depend on dose and time of exposure. The impacts of low doses of copper and low doses of radiation are greater than additive, medium levels of copper alone have a similar level of effect of bystander signal toxicity to the low dose. The addition of radiation stress, however, produces clear protective effects in the reporters treated with skin-derived medium. Gill-derived medium from the same fish did not show protective effects. Radiation exposure in the presence of 80 ?g/L led to highly variable results, which due to animal variation were not significantly different from the effect of copper alone. The results are stressor type, stressor concentration and time dependent. Clearly co-exposure to radiation and heavy metals does not always lead to simple additive effects. PMID:24352529

Mothersill, Carmel; Smith, Richard W; Heier, Lene Sørlie; Teien, Hans-Christian; Lind, Ole Christian; Land, Ole Christian; Seymour, Colin B; Oughton, Deborah; Salbu, Brit

2014-03-01

223

Revisit the radiative decays of J/{psi} and {psi}{sup '}{yields}{gamma}{eta}{sub c}({gamma}{eta}{sub c}{sup '})  

SciTech Connect

With the new measurements of J/{psi} and {psi}{sup '}{yields}{gamma}{eta}{sub c}({gamma}{eta}{sub c}{sup '}) from the CLEO and BES-III collaboration, we reinvestigate the intermediate meson loop (IML) contributions to these radiative decays in association with the quark model M1 transitions in an effective Lagrangian approach. It shows that the ''unquenched'' effects due to the intermediate hadron loops can be better quantified by the new data for J/{psi}{yields}{gamma}{eta}{sub c}. Although the IML contributions are relatively small in J/{psi}{yields}{gamma}{eta}{sub c}, they play a crucial role in {psi}{sup '}{yields}{gamma}{eta}{sub c}({gamma}{eta}{sub c}{sup '}). A prediction for the IML contributions to {psi}(3770){yields}{gamma}{eta}{sub c}({gamma}{eta}{sub c}{sup '}) is made. Such unquenched effects allow us to reach a coherent description of those three radiative transitions, and gain some insights into the underlying dynamics.

Li Gang [Department of Physics, Qufu Normal University, Qufu, 273165 (China); Zhao Qiang [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049 (China)

2011-10-01

224

Foods for a Mission to Mars: Investigations of Low-Dose Gamma Radiation Effects  

NASA Technical Reports Server (NTRS)

Food must be safe, nutritious, and acceptable throughout a long duration mission to maintain the health, well-being, and productivity of the astronauts. In addition to a developing a stable pre-packaged food supply, research is required to better understand the ability to convert edible biomass into safe, nutritious, and acceptable food products in a closed system with many restrictions (mass, volume, power, crew time, etc.). An understanding of how storage conditions encountered in a long-term space mission, such as elevated radiation, will impact food quality is also needed. The focus of this project was to contribute to the development of the highest quality food system possible for the duration of a mission, considering shelf-stable extended shelf-life foods, bulk ingredients, and crops to be grown in space. The impacts of space-relevant radiation doses on food, bulk ingredient, and select candidate crop quality and antioxidant capacity were determined. Interestingly, increasing gamma-radiation doses (0 to 1000 Gy) did not always increase dose-related effects in foods. Intermediate radiation doses (10 to 800Gy) often had significantly larger impact on the stability of bulk ingredient oils than higher (1000Gy) radiation doses. Overall, most food, ingredient, and crop systems investigated showed no significant differences between control samples and those treated with 3 Gy of gamma radiation (the upper limit estimated for a mission to Mars). However, this does not mean that all foods will be stable for 3-5 years, nor does it mean that foods are stable to space radiation comprising more than gamma rays.

Gandolph, J.; Shand, A.; Stoklosa, A.; Ma, A.; Weiss, I.; Alexander, D.; Perchonok, M.; Mauer, L. J.

2007-01-01

225

Measurements of longitudinal gamma ray distribution using a multichannel fiber-optic Cerenkov radiation sensor  

NASA Astrophysics Data System (ADS)

Cerenkov radiation occurs when charged particles are moving faster than the speed of light in a transparent dielectric medium. In optical fibers, Cerenkov radiation can also be generated due to the fiber’s dielectric components. Accordingly, the radiation-induced light signals can be obtained using the optical fibers without any scintillating material. In this study, we fabricated a multichannel, fiber-optic Cerenkov radiation sensor (FOCRS) system using silica optical fibers (SOFs), plastic optical fibers (POFs), an optical spectrometer, multi-anode photomultiplier tubes (MA-PMTs) and a scanning system to measure the light intensities of Cerenkov radiation induced by gamma rays. To evaluate the fading effects in optical fibers, the spectra of Cerenkov radiation generated in the SOFs and POFs were measured based on the irradiation time by using an optical spectrometer. In addition, we measured the longitudinal distribution of gamma rays emitted from the cylindrical type Co-60 source by using MA-PMTs. The result was also compared with the distribution of the electron flux calculated by using the Monte Carlo N-particle transport code (MCNPX).

Shin, S. H.; Jeon, D.; Kim, J. S.; Jang, J. S.; Jang, K. W.; Yoo, W. J.; Moon, J. H.; Park, B. G.; Kim, S.; Lee, B.

2014-11-01

226

Effect of exposure to low-dose [gamma] radiation during late organogenesis in the mouse fetus  

SciTech Connect

The adominal region of pregnant Swiss mice was exposed to 0.05 to 0.50 of [gamma] radiation on day 11.5 postcoitus. The animals were sacrificed on day 18 gestation and the fetuses were examined for mortality, growth retardation, changes in head size and brain weight, and incidence of microphthalmia. No marked increase in fetal mortality or growth retardation was observed below 0.25 Gy; the increase in these parameters was significant only at 0.50 Gy. A significant reduction in head size and brain weight and a significant increase in the incidence of microphthalmia were observed at doses above 0.15 Gy. Detectable levels of microcephaly and microphthalmia were evident even at 0.10 Gy. A linear dose response was seen for these effects in the dose range of 0.05 to 0.15 Gy. It is concluded that the late period of organogenesis in the mouse, especially between days 10 and 12 postcoitus, is a particularly sensitive phase in the development of the skull, brain and eye. 21 refs., 4 figs., 4 tabs.

Devi, P.U.; Baskar, R.; Hande, M.P. (Kasturba Medical College, Manipal (India))

1994-04-01

227

Effects of gamma radiation on Clostridium botulinum type E under various parameters  

SciTech Connect

Spores of Clostridium botulinum type E strain Eklund (Eklund) was irradiated with gamma radiation and its recovery was tested on the tryptone-peptone-glucose-yeast extract-agar (TPGYA) containing various levels of NaCl and Na-thioglycollate. The presence of 0.5% or more NaCl in the media decreased the viable counts, while Na-thioglycollate of up to 0.15% did not affect the recovery of both irradiated and non-irradiated spores. Eklund spores were also irradiated under air (21% O/sub 2/), N/sub 2/O and N/sub 2/, with or without the additive of one of the following agents (additive/concentration): disodium ethylenediaminetetraacetate (EDTA), 0.01 M; t-butanol, 0.1 M; NaCl, 0.01 M; catalyze, 10 mg/ml and DL-cysteine, 0.1 mM. Radiation process was most effective in destroying the spores when carried out under air (21% O/sub 2/), followed by N/sub 2/O and N/sub 2/. Among the additives tested, EDTA was the most efficient protector followed by t-butanol when irradiation process was carried under N/sub 2/O and N/sub 2/ gas environment. Catalase and DL-cysteine sensitized the spores when irradiated under N/sub 2/O and N/sub 2/, while NaCl only sensitized under N/sub 2/. Spores kept frozen at -75/sup 0/C for 30 days but thawed prior to irradiation were more sensitive to radiation damage than freshly prepared spores. Radiation resistance of the spores increased when 15% glycerol was added to the phosphate bugger (0.06 M, pH 7.0) and used as suspending media. When the concentration of the spore increased from 10/sup 6//ml to 10/sup 11//ml, the radiosensitivities also increased. Seven strains of C. botulinum type E were screened for plasmids by agarose gel electrophoresis.

Lim, Y.H.

1986-01-01

228

Shield optimization program: Part 4, Effects of neutron and gamma-ray radiations from nuclear weapons on SDI weapon platforms  

SciTech Connect

Initial studies have been completed to estimate the radiation induced damage in silicon based electronic components onboard a representative Space Based Interceptor (SBI) weapon platform. The SBI weapon platform model used in the studies represents the author's concept of such a system. The analysis was completed for neutrons and gamma rays emanating from a nuclear weapon detonation in space. Results indicate dose levels to the sensitive components within the SBI weapon platform may exceed design limits if the weapon is detonated within a critical radius. For example, a 1962 Starfish detonation at a distance of 91.4 km from the SBI weapon platform generates a total dose in the central instrument bay of 964 rads(Si). The dose rate, /dot /gamma//, assuming a 40 nsec deposition time, is 1 /times/ 10/sup 10/ rads(Si)/sec. All of the calculations were carried out for an unshielded SBI weapon platform to determine the radiation levels for which shielding must be designed to ensure survivability of the electronic systems. 10 refs., 7 figs., 13 tabs.

Smith, M.S.; Johsnon, J.O.; Gabriel, T.A.; Barnes, J.M.; Drischler, J.D.; Santoro, R.T.

1989-03-01

229

Radiation-induced reductions in transporter mRNA levels parallel reductions in intestinal sugar transport  

PubMed Central

More than a century ago, ionizing radiation was observed to damage the radiosensitive small intestine. Although a large number of studies has since shown that radiation reduces rates of intestinal digestion and absorption of nutrients, no study has determined whether radiation affects mRNA expression and dietary regulation of nutrient transporters. Since radiation generates free radicals and disrupts DNA replication, we tested the hypotheses that at doses known to reduce sugar absorption, radiation decreases the mRNA abundance of sugar transporters SGLT1 and GLUT5, prevents substrate regulation of sugar transporter expression, and causes reductions in sugar absorption that can be prevented by consumption of the antioxidant vitamin A, previously shown by us to radioprotect the testes. Mice were acutely irradiated with 137Cs gamma rays at doses of 0, 7, 8.5, or 10 Gy over the whole body. Mice were fed with vitamin A-supplemented diet (100× the control diet) for 5 days prior to irradiation after which the diet was continued until death. Intestinal sugar transport was studied at days 2, 5, 8, and 14 postirradiation. By day 8, d-glucose uptake decreased by ?10–20% and d-fructose uptake by 25–85%. With increasing radiation dose, the quantity of heterogeneous nuclear RNA increased for both transporters, whereas mRNA levels decreased, paralleling reductions in transport. Enterocytes of mice fed the vitamin A supplement had ? 6-fold retinol concentrations than those of mice fed control diets, confirming considerable intestinal vitamin A uptake. However, vitamin A supplementation had no effect on clinical or transport parameters and afforded no protection against radiation-induced changes in intestinal sugar transport. Radiation markedly reduced GLUT5 activity and mRNA abundance, but high-d-fructose diets enhanced GLUT5 activity and mRNA expression in both unirradiated and irradiated mice. In conclusion, the effect of radiation may be posttranscriptional, and radiation-damaged intestines can still respond to dietary stimuli. PMID:19907007

Roche, Marjolaine; Neti, Prasad V. S. V.; Kemp, Francis W.; Agrawal, Amit; Attanasio, Alicia; Douard, Veronique; Muduli, Anjali; Azzam, Edouard I.; Norkus, Edward; Brimacombe, Michael; Howell, Roger W.

2010-01-01

230

Gamma radiation effects on phenolics, antioxidants activity and in vitro digestion of pistachio ( Pistachia vera) hull  

NASA Astrophysics Data System (ADS)

The effect of gamma radiation (10, 20, 30, 40, 50 and 60 kGy) on tannin, total phenolics, antioxidants activity and in vitro digestion of pistachio hulls has been investigated in this study. The possibility of using the radial diffusion method based on software measurement of the rings area has also been investigated in this study. The software based method in radial diffusion method showed a higher r2 (0.995) value when compared to the traditional method. Irradiation reduced the tannin content ( P<0.01) and activity of antioxidants ( P<0.05) of pistachio hull extracts but increased the total phenolic content ( P<0.05). There was no effect of gamma irradiation on the in vitro digestion of the pistachio hull. Irradiation decreased the digestion rate of the pistachio hull at the dose of 40 kGy when compared to the control. This study showed that gamma irradiation decreased tannin and antioxidants activity of pistachio hull.

Behgar, M.; Ghasemi, S.; Naserian, A.; Borzoie, A.; Fatollahi, H.

2011-09-01

231

Heterogenization of precious metal catalysts and enzymes by radiation-induced graft copolymerization. [Gamma or ultraviolet radiation  

SciTech Connect

The feasibility of using radiation graft copolymerization for the preparation of supports suitable for the heterogenization of catalysts was examined. To bind metal complexes, radiation graft copolymers of p-styryldiphenylphosphine with a number of trunk polymers were produced. Similarly enzyme immobilization was successful on chemically modified p-nitrostyrene copolymers. Conditions for ..gamma.. and/or UV radiation grafting of styrene, p-styryldiphenylphosphine, vinyldiphenylphosphine and p-nitrostyrene to a number of trunk polymers were established. New techniques to chemically modify styrene copolymers and to analyze the resultant catalysts were adapted from traditional methods. Procedures to assess the catalytic activity of the heterogenized catalysts were also developed from techniques used in conventional catalytic research.

Levot, R.G.

1983-01-01

232

The Contribution of Tissue Level Organization to Genomic Stability Following Low Dose/Low Dose Rate Gamma and Proton Irradiation  

SciTech Connect

The formation of functional tissue units is necessary in maintaining homeostasis within living systems, with individual cells contributing to these functional units through their three-dimensional organization with integrin and adhesion proteins to form a complex extra-cellular matrix (ECM). This is of particular importance in those tissues susceptible to radiation-induced tumor formation, such as epithelial glands. The assembly of epithelial cells of the thyroid is critical to their normal receipt of, and response to, incoming signals. Traditional tissue culture and live animals present significant challenges to radiation exposure and continuous sampling, however, the production of bioreactor-engineered tissues aims to bridge this gap by improve capabilities in continuous sampling from the same functional tissue, thereby increasing the ability to extrapolate changes induced by radiation to animals and humans in vivo. Our study proposes that the level of tissue organization will affect the induction and persistence of low dose radiation-induced genomic instability. Rat thyroid cells, grown in vitro as 3D tissue analogs in bioreactors and as 2D flask grown cultures were exposed to acute low dose (1, 5, 10 and 200 cGy) gamma rays. To assess immediate (6 hours) and delayed (up to 30 days) responses post-irradiation, various biological endpoints were studied including cytogenetic analyses, apoptosis analysis and cell viability/cytotoxicity analyses. Data assessing caspase 3/7 activity levels show that, this activity varies with time post radiation and that, overall, 3D cultures display more genomic instability (as shown by the lower levels of apoptosis over time) when compared to the 2D cultures. Variation in cell viability levels were only observed at the intermediate and late time points post radiation. Extensive analysis of chromosomal aberrations will give further insight on the whether the level of tissue organization influences genomic instability patterns after low dose radiation exposure. Cells viability/cytotoxicity analysis data are currently being analyzed to determine how these endpoints are affected under our experimental conditions. The results from this study will be translatable to risk assessment for assigning limits to radiation workers, pre-dosing for more effective radiotherapy and the consequences of long duration space flight. The data from this study has been presented a various scientific meetings/workshops and a manuscript, containing the findings, is currently being prepared for publication. Due to unforeseen challenges in collecting the data and standardizing experimental procedures, the second and third aims have not been completed. However, attempts will be made, based on the availability of funds, to continue this project so that these aims can be satisfied.

Cheryl G. Burrell, Ph.D.

2012-05-14

233

Gamma-ray detectors for intelligent, hand-held radiation monitors  

SciTech Connect

Small radiation detectors based on HgI/sub 2/, bismuth germanate (BGO), plastic, or NaI(Tl) detector materials were evaluated for use in small, lighweight radiation monitors. The two denser materials, HgI/sub 2/ and BGO, had poor resolution at low-energy and thus performed less well than NaI(Tl) in detecting low-energy gamma rays from bare, enriched uranium. The plastic scintillator, a Compton recoil detector, also performed less well at low gamma-ray energy. Two small NaI(Tl) detectors were suitable for detecting bare uranium and sheilded plutonium. One became part of a new lightweight hand-held monitor and the other found uses as a pole-mounted detector for monitoring hard-to-reach locations.

Fehlau, P.E.

1983-01-01

234

Development and characterization of starch nanoparticles by gamma radiation: potential application as starch matrix filler.  

PubMed

Gamma radiation arises as an advantageous alternative to obtain starch nanoparticles given its low cost, simple methodology and scalability. Starch nanoparticles (SNP) with sizes around 20 and 30 nm were obtained applying a dose of 20 kGy from cassava (CNP-?) and waxy maize (WNP-?) starch, respectively. They showed the same thermal degradation behavior and their maximum mass loss zone was similar to those nanoparticles obtained from acid hydrolysis (WNP-h). Additionally, CNP-? and WNP-? were used as nanofillers in a cassava matrix. Increments of 102% in storage modulus were obtained with the addition of only 2.5 wt.% of WNP-?, showing that gamma radiation is a successful methodology to obtain SNP able to be used as starch reinforcement. PMID:23769521

Lamanna, Melisa; Morales, Noé J; García, Nancy Lis; Goyanes, Silvia

2013-08-14

235

Operation of Bidirectional Switches (DIAC) and Silicon Controlled Rectifiers (SCR) in Gamma-Radiation Environment  

SciTech Connect

Gamma-irradiation effects on the electrical parameters of the Diode AC switch (DIAC; PHI37 500) and Silicon Controlled Rectifier (SCR; 2N4444) devices have been studied in detail, where gamma-dose up to 137 x 106 rad was found to cause a serious permanent damage on their electrical characteristics. A pronounced increase in the break-over voltage (from 31.5 to 35 V), holding-current (from 13 to 53 mA) and holding voltage (from 22 to 32 V) of the DIAC is noticed. Besides, a severe decrease in the dynamic break-over voltage range (from 10 to 2.5 V) and negative resistance (from -750 to -168 ohm) is also observed. Exposing the SCRs to gamma-radiation causes their turn-on voltage and forward voltage drop values to increase from 0.8 to 2.8 V and from 1.4 to 4.5 V, respectively. Additionally, the holding current increases to 18 mA although its initial value is 3.5 mA. For the two devices, the linear dependence and high sensitivity of their electrical parameters to gamma-dose suggest the application of such devices in the field of radiation dosimetry.

Swidan, A.M.; El-Ghanam, S.M. [Women's College for Art, Science and Education, Ain- Shams University, Helioplis, Cairo (Egypt); Soliman, F.A.S. [Nuclear Materials Authority, P.O. Box 2404, Horrya-11361, Heliopolis, Cairo (Egypt)

2005-03-17

236

Gamma Radiation Induces Micronucleated Reticulocytes in 3-D Bone Marrow Bioreactors in Vitro  

PubMed Central

Radiation injury to the bone marrow is potentially lethal due to the potent DNA-damaging effects on cells of the hematopoietic system, including bone marrow stem cell, progenitor, and the precursor cell populations. Investigation of radiation genotoxic effects on bone marrow progenitor/precursor cells has been challenged by the lack of optimal in vitro surrogate organ culture systems, and the overall difficulty to sustain lineage-specific proliferation and differentiation of hematopoiesis in vitro. We report the investigation of radiation genotoxic effects in bone marrow cultures of C57Bl/6 mice established in 3-D bioreactors, which sustain long-term bone marrow cultures. For these studies, genotoxicity is measured by the induction of micronucleated reticulocytes (MN-RET). The kinetics and dose-response relationship of MN-RET induction in response to gamma-radiation of bioreactor-maintained bone marrow cultures are presented. Our data showed that 3-D long-term bone marrow cultures had sustained erythropoiesis capable of generating reticulocytes up to 8 weeks. The peak time-interval of viable cell output and percentage of reticulocytes increased steadily and reached the initial peak between the 14th to 21st days after inoculations. This was followed by a rebound or staying relatively constant until week 8. The percentage of MN-RET reached the maximum between 24 and 32 hours post 1 Gy gamma-ray. There was a near linear MN-RET induction by gamma radiation from 0 Gy to 1.0 Gy, followed by an attenuated increase to 1.5 – 2.0 Gy. The MN-RET response showed a downtrend beyond 2 Gy. Our data suggest that bone marrow culture in the 3-D bioreactor may be a useful organ culture system for the investigation of radiation genotoxic effect in vitro. PMID:19786117

Sun, Hongliang; Dertinger, Stephen D.; Hyrien, Ollivier; David Wu, J. H.; Chen, Yuhchyau

2009-01-01

237

[Carcinogenic effects of combined exposure to 241Am and gamma-radiation].  

PubMed

In experiments on Wistar rats a study was made of the carcinogenic effects of the combined exposure to 241Am administered intraperitoneally (6.7 to 229.4 kBq/kg body weight) and external gamma-radiation (137Cs, 175 cGy). The occurrence of osteosarcoma, leucosis, skin and mammary tumors increased in the exposed animals. The combined irradiation produced an additive carcinogenic effect. PMID:6390502

Filippova, L G; Buldakov, L A; Nifatov, A P

1984-01-01

238

Interaction of water vapor with gamma-radiation-induced defects in proton conductive polymers  

Microsoft Academic Search

The correlation between protonic conduction and the amount of radiation-induced defects in gamma-ray-irradiated perfluorosulfonic acid (PFSA) polymers (Aciplex-SF-1004®) has been investigated using a direct-current resistance method, transmission spectroscopy for the ultraviolet (UV) and visible (Vis) wavelength ranges and Fourier transform infrared (FTIR) spectroscopy with the attenuated total refraction (ATR) technique. The proton conductivity of the polymers, which are irradiated with

B. Tsuchiya; Y. Konishi; S. Nagata; T. Shikama

2009-01-01

239

Immobilization of Urease on (HEMA\\/IA) Hydrogel Prepared by Gamma Radiation  

Microsoft Academic Search

In the present study, the copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization, in order to examine the potential use of these hydrogels in immobilization of Citrullus vulgaris urease. Gelation and Swelling properties of PHEMA and copolymeric P (HEMA\\/IA) hydrogels with different IA contents (96.5\\/3.5, 94.4\\/5.6 and 92.5\\/7.5 mol)

Soha M. Hamdy; Samia El-Sigeny; Manal F. Abou Taleb

2008-01-01

240

Evidence for successful acceptance of irradiated free gingival allografts in dogs. [Gamma radiation  

Microsoft Academic Search

Free graft samples were excised and frozen to -55°C. Subsequently the grafts were exposed to 2.5 x 10⁶ rads of ⁶°Co ..gamma..-radiation. The irradiated allogeneic grafts were later reconstituted and surgically transferred to four recipient subjects. Three autogenous nonirradiated grafts were also placed as controls. The animals were killed so as to furnish healing data at 0, 3, 7, 10,

H. S. Rubenstein; M. P. Ruben; C. Levy; S. Peiser

1975-01-01

241

Method for detecting water equivalent of snow using secondary cosmic gamma radiation  

DOEpatents

Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attenuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power. 4 figs.

Condreva, K.J.

1997-01-14

242

Method for detecting water equivalent of snow using secondary cosmic gamma radiation  

DOEpatents

Water equivalent of accumulated snow determination by measurement of secondary background cosmic radiation attenuation by the snowpack. By measuring the attentuation of 3-10 MeV secondary gamma radiation it is possible to determine the water equivalent of snowpack. The apparatus is designed to operate remotely to determine the water equivalent of snow in areas which are difficult or hazardous to access during winter, accumulate the data as a function of time and transmit, by means of an associated telemetry system, the accumulated data back to a central data collection point for analysis. The electronic circuitry is designed so that a battery pack can be used to supply power.

Condreva, Kenneth J. (1420 Fifth St., Livermore, Alameda County, CA 94550)

1997-01-01

243

Branching Fractions and CP-Violating Asymmetries in Radiative B Decays to eta K gamma  

SciTech Connect

The authors present measurements of the CP-violation parameters S and C for the radiative decay B{sup 0} {yields} {eta}K{sub S}{sup 0}{gamma}; for B {yields} {eta}K{gamma} they also measure the branching fractions and for B{sup +} {yields} {eta}K{sup +}{gamma} the time-integrated charge asymmetry {Alpha}{sub ch}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 x 10{sup 6} B{bar B} pairs produced in e{sup +}e{sup -} annihilation. The results are S = -0.18{sub -0.46}{sup +0.49} {+-} 0.12, C = -0.32{sub -0.39}{sup +0.40} {+-} 0.07, {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = (7.1{sub -2.0}{sup +2.1} {+-} 0.4) x 10{sup -6}, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = (7.7 {+-} 1.0 {+-} 0.4) x 10{sup -6}, and {Alpha}{sub ch} = (-9.0{sub -9.8}{sup +10.4} {+-} 1.4) x 10{sup -2}. The first error quoted is statistical and the second systematic.

Aubert, B.

2008-05-14

244

Celestial diffuse gamma radiation above 30 MeV observed by SAS-2  

NASA Technical Reports Server (NTRS)

The Small Astronomy Satellite (SAS)-2, launched on November 15, 1972, carried into orbit a 32-deck magnetic-core digitized spark chamber gamma ray telescope to study celestial gamma radiation in the energy range above 30 MeV. In the study of several regions with b sub 2 15 deg, a finite, diffuse flux of gamma rays with a steep energy spectrum in the energy region from 35 to 200 MeV is observed. Representing the energy spectrum by a power law of the form dJ/dE = AE to - alpha power over this energy range, alpha is found along with the integral flux above 100 MeV. Combining this result with existing low energy gamma ray data yields an energy spectrum which is not a simple power law in energy, as in the X-ray region, but which demonstrates first an increase and then a decrease in slope, consistent within uncertainties with that predicted by cosmological theories, including the continuous production of high energy gamma rays primarily from neutral pi mesons throughout the history of the universe.

Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

1973-01-01

245

Comparison of proton microbeam and gamma irradiation for the radiation hardness testing of silicon PIN diodes  

NASA Astrophysics Data System (ADS)

Simple and cost-effective solutions using Si PIN diodes as detectors are presently utilized in various radiation-related applications in which excessive exposure to radiation degrades their charge transport properties. One of the conventional methods for the radiation hardness testing of such devices is time-consuming irradiation with electron beam or gamma-ray irradiation facilities, high-energy proton accelerators, or with neutrons from research reactors. Recently, for the purpose of radiation hardness testing, a much faster nuclear microprobe based approach utilizing proton irradiation has been developed. To compare the two different irradiation techniques, silicon PIN diodes have been irradiated with a Co-60 gamma radiation source and with a 6 MeV proton microbeam. The signal degradation in the silicon PIN diodes for both irradiation conditions has been probed by the IBIC (ion beam induced charge) technique, which can precisely monitor changes in charge collection efficiency. The results presented are reviewed on the basis of displacement damage calculations and NIEL (non-ionizing energy loss) concept.

Jakši?, M.; Grilj, V.; Skukan, N.; Majer, M.; Jung, H. K.; Kim, J. Y.; Lee, N. H.

2013-09-01

246

Diffuse gamma radiation. [intensity, energy spectrum and spatial distribution from SAS 2 observations  

NASA Technical Reports Server (NTRS)

Results are reported for an investigation of the intensity, energy spectrum, and spatial distribution of the diffuse gamma radiation detected by SAS 2 away from the galactic plane in the energy range above 35 MeV. The gamma-ray data are compared with relevant data obtained at other wavelengths, including 21-cm emission, radio continuum radiation, and the limited UV and radio information on local molecular hydrogen. It is found that there are two quite distinct components to the diffuse radiation, one of which shows a good correlation with the galactic matter distribution and continuum radiation, while the other has a much steeper energy spectrum and appears to be isotropic at least on a coarse scale. The galactic component is interpreted in terms of its implications for both local and more distant regions of the Galaxy. The apparently isotropic radiation is discussed partly with regard to the constraints placed on possible models by the steep energy spectrum, the observed intensity, and an upper limit on the anisotropy.

Fichtel, C. E.; Simpson, G. A.; Thompson, D. J.

1978-01-01

247

The comparative effects of gamma radiation and in situ alpha particles on five strong-base anion exchange resins  

SciTech Connect

The effects of external gamma radiation and in situ alpha particles were measured on a recently available, macroporous, strong-base polyvinylpyridine resin and on four strong-base polystyrene anion exchange resins. Each resin was irradiated in 7 M nitric acid to 1--10 megaGray of gamma radiation from external {sup 60}Co, or to 5--14 megaGray of alpha particles from sorbed {sup 238}Pu. Each irradiated resin was measured for changes in dry weight, wet volume, weak-base and strong-base chloride exchange capacities, and exchange capacities for Pu(4) from nitric acid. Alpha-induced resin damage was significantly less than that caused by an equivalent dose of gamma radiation. The polyvinylpyridine resin offers the greatest resistance to damage from gamma radiation and from alpha particles. 5 refs., 1 figs. 5 tabs.

Marsh, S.F.

1991-01-01

248

SAS-2 observations of the galactic gamma radiation from the Vela region  

NASA Technical Reports Server (NTRS)

Data from a scan of the galactic plane by the SAS-2 high energy gamma ray experiment in the region 250 deg l2 290 deg show a statistically-significant excess over the general radiation from the galactic plane for gamma radiation of energy 100 MeV in the region 260 deg l2 270 deg and -7.5 deg b2 0 deg. If the enhanced gamma radiation results from interactions of cosmic rays with galactic matter, as the energy spectrum suggests, it seems reasonable to associate the enhancement with large scale galactic features, such as spiral arm segments in that direction, or with the region surrounding the Vela supernova remnant, with which PSR 0833-45 is associated. If the excess is attributed to cosmic rays released from this supernova interacting with the interstellar matter in that region, then on the order of 3.10 to the 50th power ergs would be released by that supernova in the form of cosmic rays.

Thompson, D. J.; Bignami, G. F.; Fichtel, C. E.; Kniffen, D. A.

1974-01-01

249

Methyl viologen radical reactions with several oxidizing agents. [Gamma Radiation  

SciTech Connect

The rates of oxidation of the methyl viologen radical by peroxodisulfate and hydrogen peroxide has been investigated. The methyl viologen free radical was produced by pulse radiolysis. The reaction of the peroxodisulfate radical with the methyl viologen radical was first order in both species, and the reaction rate constant is reported. A el-radiation study revealed a chain decomposition of the peroxodisulfate radical involving the methyl viologen radical when methanol, ethanol, or 2-propanol was present. Loss of the methyl viologen radical was then no longer observed to be a simple first-order reaction. The reaction of hydrogen peroxide with the methyl viologen radical was very slow in the presence of 1 M methanol. A much faster reaction in the absence of methanol was interpreted to be a reaction of the methyl viologen radical with the peroxy radicals. Hydrogen peroxide, in contrast to the chain decomposition of peroxodisulfate radicals, does not participate in a chain reaction involving the methyl viologen radical and methanol. Rate constants for the reaction of methyl viologen radical with dichromate radical, iodate radical, and ferricyanide radical are reported.

Levey, G.; Ebbesen, T.W.

1983-01-01

250

Gamma radiations induced improvement in dyeing properties and colorfastness of cotton fabrics dyed with chicken gizzard leaves extracts  

NASA Astrophysics Data System (ADS)

Cotton fabric and chicken gizzard leaves powder were treated with different absorbed doses of 5, 10, 15, 20 and 25 kGy using Cs-137 gamma irradiator. Effects of different mordants on dyeing of un-irradiated and irradiated cotton fabrics were investigated in the CIE Lab system using Spectraflash SF650. Methods suggested by International Standard Organization (ISO) were followed throughout the study period. The results indicated that color strength of cotton fabric was significantly improved by the gamma ray treatment. Absorbed dose of 10 kGy was proved to be most effective in improving cotton dyeing properties compared with other levels of gamma radiation used in the study. The optimum temperature for dyeing was 60 °C with the time duration of 60 min using 4 g/L of electrolyte with alkali solubilized extract of chicken gizzard. Furthermore, 4% of iron (Fe) as pre-mordant and 1% of tannic acid (TA) as post-mordant proved to be more effective in enhancing the color fastness properties of irradiated cotton fabric.

Batool, Fatima; Adeel, Shahid; Azeem, Muhammad; Ahmad Khan, Ali; Ahmad Bhatti, Ijaz; Ghaffar, Abdul; Iqbal, Naeem

2013-08-01

251

Gamma radiation induced damage effects in the transmission of barium fluoride and cesium fluoride fast crystal scintillators  

Microsoft Academic Search

Radiation damage effects in the optical transmission of bulk material due to 60Co gamma irradiations were measured in samples of barium fluoride (BaF2) and cesium fluoride (CsF). While confirming the exceptional radiation resistance of barium fluoride in the visible and ultraviolet regions of the transmission spectrum, at least up to a gamma dose of a few times 107 rad, the

Stan Majewski; Margaret Kathleen Bentley

1987-01-01

252

Commentary on the Appropriate Radiation Level for Evacuations1  

PubMed Central

This commentary reviews the international radiation protection policy that resulted in the evacuation of more than 90,000 residents from areas near the Fukushima Daiichi NPS and the enormous expenditures to protect them against a hypothetical risk of cancer. The basis for the precautionary measures is shown to be invalid; the radiation level chosen for evacuation is not conservative. The actions caused unnecessary fear and suffering. An appropriate level for evacuation is recommended. Radical changes to the ICRP recommendations are long overdue. PMID:23304099

Cuttler, Jerry M.

2012-01-01

253

Ambient ultraviolet radiation levels in public shade settings.  

PubMed

As people become better informed about the harmful effects of prolonged exposure to solar ultraviolet radiation (UVR, 280-400 nm) they will seek the protection of shade, particularly in tropical locations such as Townsville (19 degrees south). Using broad-band radiation sensors for solar ultraviolet-B (280-315 nm), ultraviolet-A (315-400 nm) and daylight (400-800 nm) radiation, the exposure levels were measured in both the horizontal (shaded and unshaded) and vertical (shaded and unshaded) directions. The measurements were conducted at eight locations (shade settings) in Townsville during the period between December 1997 (summer) and May 1998 (beginning of winter). The quality of protection was assessed by the ratio of unshaded to shaded radiation exposure, the UVB/shade protection ratio (UVB-SPR). The UVB-SPR varies considerably between the different shade settings, with a beach umbrella showing the least protection and dense foliage the highest protection. The roof of a house verandah can provide only little protection if the verandah catches the afternoon sun. Increasing cloud cover decreases the UVB-SPR for all settings because of the increase in the diffuse fraction of the radiation. Only one setting provided a UVB-SPR of 15 or higher, as suggested for protective shading against solar UVB radiation. Shade from direct sunlight alone does not provide enough protection against high levels of solar UVR. Apart from the transmission qualities of the shading material, it is the construction of the whole shade setting that determines the exposure levels underneath. A shade structure with enough overhang is recommended so that high levels of scattered radiation do not reach the skin. PMID:10639905

Moise, A F; Aynsley, R

1999-11-01

254

Effects of cobalt-60 gamma-irradiation in association with prostaglandin E1 treatment on the cyclic AMP levels of some radiosensitive tissues.  

PubMed

The amounts of cyclic AMP in brain, liver and intestinal mucosa have been measured in rats, at constant intervals, up to 18 days after whole-body exposure to either a unique moderate dose (500 rd) or a unique lethal dose (750 rd) of cobalt-60 gamma-radiation in association with a preliminary intraperitoneally treatment with prostaglandin E1 (5 microgram/100 g body weight/day) during five days. The amounts of tissular cyclic AMP in these two experimental groups were compared with those obtained from control groups identically irradiated or treated with prostaglandin E1. The effects of gamma-irradiation and prostaglandin E1 treatment on the cyclic AMP levels were found to be quite specific in these organs, suggesting that they contain different adenyl cyclase-cyclic AMP-phosphodiesterase systems: a cerebral system which is influenced by both gamma-radiation and prostaglandin E1, a hepatic system which is "radioresistant" and an intestinal system which is not influenced by prostaglandin E1. When associated with gamma-radiation, this prostaglandin is capable, on the one hand, to annul the "radioresistance" of the hepatic cyclic AMP system and, on the other hand, to annul the "radiosensitivity" of the intestinal cyclic AMP system. PMID:201052

P?u?escu, E; Popescu, M V; Teodosiu, T; P?un, C; Chirvasie, R; Simionescu, A

1977-11-01

255

Prediction of ozone levels using a Hidden Markov Model (HMM) with Gamma distribution  

NASA Astrophysics Data System (ADS)

Ground level ozone, generated by the photochemical reaction between nitrogen oxides and volatile hydrocarbons, is harmful to humans and the environment. Prediction and forecasting play an important role in the regulatory policies aimed at the control and reduction of surface ozone. Belonging to the family of model-driven statistical models, Hidden Markov Models (HMMs) provide a rich mathematical structure and perform well in many applications. While conventional HMM applications assume Gaussian distribution for the observation statistics, several key meteorological factors and most ozone precursors exhibit a non-Gaussian distribution, which would weaken the performance of a conventional HMM in modeling ozone exceedances. We propose a method based on a HMM with a Gamma distribution (HMM-Gamma) where each monitoring day is pre-labeled according to its maximum 8-h average ozone concentration and monitoring days are further grouped into zones with different ozone levels. Then, HMMs associated with each zone are trained using air quality monitoring data where the model parameters are estimated by a modified Expectation-Maximization (EM) algorithm. We derive a new re-estimation formula for the model parameters for observation sequences that exhibit a Gamma distribution. The trained HMM-Gamma models are used to predict ozone exceedances in two geographic areas, Livermore Valley near San Francisco, CA and Houston Metropolitan Area, TX. Compared to the conventional HMM (HMM-Gaussian), HMM-Gamma for the ground level ozone in Livermore Valley can reduce false alarms by 77% and HMM-Gamma for that in Houston Metropolitan Area can reduce false alarms by 32%.

Zhang, Hao; Zhang, Weidong; Palazoglu, Ahmet; Sun, Wei

2012-12-01

256

RADIATION CHEMISTRY OF CARBOHYDRATES. PART IV. THE EFFECT OF GAMMA RADIATION ON AQUEOUS SOLUTION OF SUCROSE  

Microsoft Academic Search

Yield-dose curves obtained from isotope dilution and paper ; chromatographic methods reveal that glucose and fructose are primary products of ; gamma -irradiation of aqueous sucrose solutions, together with smaller amounts of ; glucosone and gluconic acid. Glucuronic acid, 2-oxogluconic acid, arabinose, and ; two- and three-carbon aldehydic fragments arise in secondary processes. In the ; final stages carbon dioxide

G. O. Phillips; G. J. Moody

1960-01-01

257

Level density and gamma-ray strength function in the odd-odd 238Np  

E-print Network

The level density and gamma-ray strength function in the quasi-continuum of 238Np has been measured using the Oslo method. The level density function follows closely the constant-temperature level density formula and reaches 43 million levels per MeV at Sn = 5.488 MeV of excitation energy. The gamma-ray strength function displays a two-humped resonance at low-energy as also seen in previous investigations of Th, Pa and U isotopes. The structure is interpreted as the scissors resonance and has an average centroid of wSR = 2.26(5) MeV and a total strength of BSR = 10.8(12)m2N, which is in excellent agreement with sum-rule estimates. The scissors resonance is shown to have an impact on the 237Np(n; g)238Np cross section.

Tamás Gábor Tornyi; Magne Guttormsen; Tomas Kvalheim Eriksen; Andreas Görgen; Francesca Giacoppo; Trine Wiborg Hagen; Attila Krasznahorkay; Ann-Cecilie Larsen; Therese Renstrøm; Sunniva Johanne Rose; Sunniva Siem; Gry Merete Tveten

2014-02-25

258

Occupational exposure to radon and natural gamma radiation in the La Carolina, a former gold mine in San Luis Province, Argentina  

Microsoft Academic Search

Radon and gamma radiation level measurements were carried out inside the La Carolina mine, one of the oldest gold mining camps of southern South America, which is open for touristic visits nowadays. CR-39 track-etch detectors and thermoluminescent dosimeters of natural CaF2 and LiF TLD-100 were exposed at 14 points along the mine tunnels in order to estimate the mean 222Rn

R. M. Anjos; N. Umisedo; A. A. R. da Silva; L. Estellita; M. Rizzotto; E. M. Yoshimura; H. Velasco; A. M. A. Santos

2010-01-01

259

Carnosine mitigates apoptosis and protects testicular seminiferous tubules from gamma-radiation-induced injury in mice.  

PubMed

This study investigated the radioprotective effects of a naturally occurring dipeptide, carnosine, on testicular damage. Carnosine was administered (10, 50 and 100 mg kg(-1) body weight) to male mice via intraperitoneal injection for 4 days prior to gamma irradiation (2 Gy). Apoptosis with the TUNEL assay and histopathological parameters were evaluated 12-h and 14-day post-irradiation. Pre-treatment with carnosine before irradiation significantly reduced the frequency of TUNEL-positive cells induced by radiation treatment at all doses by reduction factors of 1.8, 2.47 and 2.23 for carnosine at 10, 50 and 100 mg kg(-1) bw, respectively, unlike that observed in the radiation alone group. Exposure to ionising radiation decreased sperm count and reduced the height and diameter of seminiferous epithelial tubules. Pre-treatment with all doses of carnosine significantly augmented seminiferous epithelial height and tubule diameter and also increased the number of germinal cells in comparison to the group treated with radiation only. These results indicate that carnosine prevents testicular dysfunction induced by gamma-irradiation via an anti-apoptotic effect; this restoration of proper testicular function ultimately leads to the recovery of spermatogenesis. PMID:24215656

Haeri, S A; Rajabi, H; Fazelipour, S; Hosseinimehr, S J

2014-11-01

260

Size effects on gamma radiation response of magnetic properties of barium hexaferrite powders  

NASA Astrophysics Data System (ADS)

Little is currently known about the effects of gamma-ray irradiation on oxide magnet materials. In particular, the effect of particle size on radiation susceptibility was investigated. Two commercial powders of BaFe12O19 were thoroughly characterized, then exposed to 1 MGy of gamma radiation from a 60Co source. AC susceptibility and DC magnetometry and Mössbauer spectroscopy were performed after irradiation and compared to pre-irradiated measurements. DC magnetization and AC susceptibility decreased for both samples with the relative change of DC magnetization being larger for the micrometer-sized particles and the relative change of the AC susceptibility being larger for the nanometer-sized particles. Mössbauer spectroscopy indicated a decrease in both the hyperfine fields and in their distribution for each Fe site, particularly in the larger particle sample. Decreases in susceptibility are believed to be due to radiation-induced amorphization at the particle surfaces as well as amorphization and nucleation of new crystallites at internal crystallite boundaries, resulting in overall reduction in the particle magnetic moment. This radiation damage mechanism is different than that seen in previous studies of neutron and heavy ion irradiation of BaFe12O19.

McCloy, John; Kukkadapu, Ravi; Crum, Jarrod; Johnson, Brad; Droubay, Tim

2011-12-01

261

An improved analysis of Higgs boson decay $H \\to \\gamma \\gamma$ up to three-loop level  

E-print Network

The principle of maximum conformality (PMC) provides a systematic way for setting the optimal renormalization scale to high energy processes. This is due to the fact that by using the PMC scale setting, all non-conformal terms in perturbative series can be resummed into the running coupling, and one obtains a unique, scale-fixed, scheme-independent prediction at any finite order. As an important point of deriving reliable PMC estimation, it is noted that only those $\\{\\beta_i\\}$-terms that rightly determine the behavior of coupling constant via the renormalization group equation should be absorbed into the coupling constant to form a conformal series, and those $\\{\\beta_i\\}$-terms that are related to the quark mass renormalization and etc. should be kept as a separate. In this paper, we make a detailed PMC analysis on Higgs decay $H\\rightarrow \\gamma\\gamma$ up to three-loop level. We suggest a way to set the PMC scales for high energy processes unambiguously. That is, to avoid confusion of separating and abso...

Wang, Sheng-Quan; Zheng, Xu-Chang; Chen, Gu; Shen, Jian-Ming

2013-01-01

262

Effect of Grating Fabrication on Radiation Sensitivity of Fiber Bragg Gratings in Gamma Radiation Field  

Microsoft Academic Search

The influence of grating fabrication on radiation sensitivity of the FBGs has been investigated experimentally. The FBGs were fabricated in different process and concen- trations. Pre-irradiation and -loading were applied to change the radiation sensitivity of the FBGs. The FBGs were fabricated in photosensitive fiber and coupling single mode fiber with a concentration in a range from 0.33 to 23

Song Lin; Ningfang Song; Jing Jin; Xueqin Wang; Gongliu Yang

2011-01-01

263

Indoleamine 2,3-dioxygenase mediates immune-independent human tumor cell resistance to olaparib, gamma radiation, and cisplatin  

PubMed Central

Indoleamine 2,3-dioxygenase-1 (IDO) is an immunosuppressive molecule expressed by most human tumors. IDO levels correlate with poor prognosis in cancer patients and IDO inhibitors are under investigation to enhance endogenous anticancer immunosurveillance. Little is known of immune-independent functions of IDO relevant to cancer therapy. We show, for the first time, that IDO mediates human tumor cell resistance to a PARP inhibitor (olaparib), gamma radiation, cisplatin, and combined treatment with olaparib and radiation, in the absence of immune cells. Antisense-mediated reduction of IDO, alone and (in a synthetic lethal approach) in combination with antisense to the DNA repair protein BRCA2 sensitizes human lung cancer cells to olaparib and cisplatin. Antisense reduction of IDO decreased NAD+ in human tumor cells. NAD+ is essential for PARP activity and these data suggest that IDO mediates treatment resistance independent of immunity and at least partially due to a previously unrecognized role for IDO in DNA repair. Furthermore, IDO levels correlated with accumulation of tumor cells in G1 and depletion of cells in G2/M of the cell cycle, suggesting that IDO effects on cell cycle may also modulate sensitivity to radiation and chemotherapeutic agents. IDO is a potentially valuable therapeutic target in cancer treatment, independent of immune function and in combination with other therapies. PMID:24784564

Vareki, Saman Maleki; Rytelewski, Mateusz; Figueredo, Rene; Chen, Di; Ferguson, Peter J.; Vincent, Mark; Min, Weiping; Zheng, Xiufen; Koropatnick, James

2014-01-01

264

Proteomic analysis of global changes in protein expression during exposure of gamma radiation in Bacillus sp. HKG 112 isolated from saline soil.  

PubMed

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a full-system understanding of the radiation stress protection mechanisms of bacteria in different environments. PMID:21715963

Gupta, Anil Kumar; Pathak, Rajiv; Singh, Bharat; Gautam, Hemlata; Kumar, Ram; Kumar, Raj; Arora, Rajesh; Gautam, Hemant

2011-06-01

265

Gravitational Radiations from the Precession Central Engine in Gamma-Ray Bursts  

NASA Astrophysics Data System (ADS)

The ultra-relativistic precessing jet in gamma-ray bursts (GRBs) may be responsible for the complex structure in GRBs' light curves. In this work, we study the gravitational radiations of jet precession induced by neutrino-dominated accretion disks around black holes. In our model, the jet and the inner part of the disk may precess along with the black hole, which is driven by the outer part of the disk. Gravitational radiations are therefore expected to be significant from this precession system. Based our numerical results, we find that it is possible for DECIGO and BBO to detect such gravitational radiations regardless of GRBs' black hole masses, particularly for GRBs in the Local Group.

Sun, Mou-Yuan; Liu, Tong; Gu, Wei-Min; Lu, Ju-Fu

266

The effects of radiative transfer on low-level cyclogenesis  

SciTech Connect

Many investigators have documented the role that thermodynamic forcing due to radiative flux divergence plays in the enhancement or generation of circulation. Most of these studies involve large-scale systems, small-scale systems such as thunderstorms, and squall lines. The generation of circulation on large scales results from the creation of divergence in the upper troposphere and the maintenance of low-level potentially unstable air, and the maintenance of baroclinicity throughout the atmosphere. On smaller scales, radiative flux divergence acts similarly. In the thunderstorms and squall lines, the radiative forcing acts as a pump, increasing the divergence at the top of the storm systems and increasing the updraft velocity and the intensity of inflow at mid-levels in the storm systems. Other researchers have examined the role of surface processes and low-level baroclinicity in east coast cyclogenesis. In this paper, we examine the interactive role that radiative flux divergence, clouds, and surface processes play in low-level cyclogenesis and the creation or maintenance of the boundary layer baroclinicity.

Leach, M.J.; Raman, S. [North Carolina State Univ., Raleigh, NC (United States)

1995-04-01

267

Studies on production of fructo-oligosaccharides (FOS) by gamma radiation processing of microbial levan.  

PubMed

Microbial levan, a natural polymer of fructose, was produced and purified by alcohol precipitation from culture supernatants of Bacillus megaterium type 1 grown in an optimized liquid sucrose medium. GPC analysis showed that the yield of the major fraction of levan having molecular weight ~5000 D increased with increase in sucrose concentration in the broth. Levan subjected to (60)Co-gamma radiation as well as acid hydrolysis was investigated by rheometry, UV-visible spectrophotometry and gel permeation chromatography (GPC) techniques. Unlike most of the polysaccharides, levan powder exhibited good radiation degradation stability up to 150 kGy. Gamma irradiation of 10% levan aqueous solution at 250 kGy yielded 63.0% fructo-oligosaccharide (FOS) with an average molecular weight of 1250 D. Acid hydrolysis of levan using 0.5 N HCl for 60 min treatment time gave rise to the desired FOS with lower yield (23.1%) as compared to that obtained in gamma radiolysis process. PMID:23688493

Jalan, N; Varshney, Lalit; Misra, Nilanjal; Paul, Jhimli; Mitra, D; Rairakhwada, D D; Bhathena, Z; Kumar, Virendra

2013-07-01

268

Effect of gamma radiation on growth and survival of common seed-borne fungi in India  

NASA Astrophysics Data System (ADS)

The present work describes radiation-induced effects of major seeds like Oryza sativa Cv-2233, Oryza sativa Cv-Shankar, Cicer arietinum Cv-local and seed-borne fungi like Alternaria sp., Aspergillus sp., Trichoderma sp. and Curvularia sp. 60Co gamma source at 25 °C emitting gamma ray at 1173 and 1332 keV energy was used for irradiation. Dose of gamma irradiation up to 3 kGy (0.12 kGy/h) was applied for exposing the seed and fungal spores. Significant depletion of the fungal population was noted with irradiation at 1-2 kGy, whereas germinating potential of the treated grain did not alter significantly. However, significant differential radiation response in delayed seed germination, colony formation of the fungal spores and their depletion of growth were noticed in a dose-dependent manner. The depletion of the fungal viability (germination) was noted within the irradiation dose range of 1-2 kGy for Alternaria sp. and Aspergillus sp., while 0.5-1 kGy for Trichoderma sp. and Curvularia sp. However, complete inhibition of all the selected fungi was observed above 2.5 kGy.

Maity, J. P.; Chakraborty, A.; Chanda, S.; Santra, S. C.

2008-07-01

269

Possible using of gamma ray measurements for monitoring and prediction of radiation hazard  

NASA Astrophysics Data System (ADS)

On the basis of data on flare energetic particle generation and propagation in the Heliosphere we calculate the space-time-energy distribution of these particles in the Heliosphere in the periods of great events. On the basis of observation data and investigations of cosmic ray nonlinear processes in the Heliosphere we determine the space-time distribution of solar wind matter. Then we calculate the generation of gamma-rays by decay of neutral pions generated in nuclear interactions of flare energetic particles with solar wind matter and determine the expected space-time distribution of gamma-ray emissivity. Then we calculate the expected time variation of the angle distribution and energy spectrum of gamma ray fluxes generated by interaction of flare energetic particles with solar wind matter for observations on the Earth's orbit from satellites, rockets and balloons or from space-probes on different distances from the Sun. We show that these measurements by gamma ray telescopes directed in few degrees from the Sun will give important information on flare energetic particle energy spectrum in source and information on propagation parameters in the interplanetary space in vicinities of the Sun. On the basis of this information can be made exact forecast of expected radiation hazards.

Dorman, Lev I.

2001-08-01

270

Consequences of Lethal-Whole-Body Gamma Radiation and Possible Ameliorative Role of Melatonin  

PubMed Central

Gamma radiation induces the generation of free radicals, leading to serious cellular damages in biological systems. Radioprotectors act as prophylactic agents that are administered to shield normal cells and tissues from the deleterious effects of radiation. Melatonin synergistically acts as an immune-stimulator and antioxidant. We investigated the possible radioprotective role of melatonin (100?mg/kg i.p.) against lethal-whole-body radiation- (10?Gy) induced sickness, body weight loss, and mortality in rats. Results of the present study suggest that exposure to lethal-whole-body radiation incurred mortality, body weight loss, and apoptosis and it also depleted the immunity and the antioxidant status of the rats. Our results show that melatonin pretreatment provides protection against radiation induced mortality, oxidative stress, and immune-suppression. The melatonin pretreated irradiated rats showed less change in body weight as compared to radiation only group. On the other hand, melatonin appeared to have another radioprotective role, suggesting that melatonin may reduce apoptosis through a caspase-3-mediated pathway by blocking caspase-3 activity.

Mihandoost, Ehsan; Shirazi, Alireza; Mahdavi, Seied Rabie; Aliasgharzadeh, Akbar

2014-01-01

271

Dynamical dipole gamma radiation in heavy-ion collisions on the basis of a quantum molecular dynamics model  

SciTech Connect

Dynamical dipole gamma-ray emission in heavy-ion collisions is explored in the framework of the quantum molecular dynamics model. The studies are focused on systems of {sup 40}Ca bombarding {sup 48}Ca and its isotopes at different incident energies and impact parameters. Yields of gamma rays are calculated and the centroid energy and dynamical dipole emission width of the gamma spectra are extracted to investigate the properties of gamma emission. In addition, sensitivities of dynamical dipole gamma-ray emission to the isospin and the symmetry energy coefficient of the equation of state are studied. The results show that detailed study of dynamical dipole gamma radiation can provide information on the equation of state and the symmetry energy around the normal nuclear density.

Wu, H. L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100080 (China); Tian, W. D.; Ma, Y. G.; Cai, X. Z.; Chen, J. G.; Fang, D. Q.; Guo, W.; Wang, H. W. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800 (China)

2010-04-15

272

41 CFR 50-204.35 - Application for variations from radiation levels.  

Code of Federal Regulations, 2011 CFR

...true Application for variations from radiation levels. 50-204.35 Section...STANDARDS FOR FEDERAL SUPPLY CONTRACTS Radiation Standards § 50-204.35 Application for variations from radiation levels. (a) In accordance...

2011-07-01

273

41 CFR 50-204.35 - Application for variations from radiation levels.  

...false Application for variations from radiation levels. 50-204.35 Section...STANDARDS FOR FEDERAL SUPPLY CONTRACTS Radiation Standards § 50-204.35 Application for variations from radiation levels. (a) In accordance...

2014-07-01

274

41 CFR 50-204.35 - Application for variations from radiation levels.  

Code of Federal Regulations, 2013 CFR

...false Application for variations from radiation levels. 50-204.35 Section...STANDARDS FOR FEDERAL SUPPLY CONTRACTS Radiation Standards § 50-204.35 Application for variations from radiation levels. (a) In accordance...

2013-07-01

275

41 CFR 50-204.35 - Application for variations from radiation levels.  

Code of Federal Regulations, 2012 CFR

...true Application for variations from radiation levels. 50-204.35 Section...STANDARDS FOR FEDERAL SUPPLY CONTRACTS Radiation Standards § 50-204.35 Application for variations from radiation levels. (a) In accordance...

2012-07-01

276

Thermoluminescence behavior of KClXBr1-X: In mixed crystals exposed to gamma radiation  

NASA Astrophysics Data System (ADS)

In-doped KClXBr1-X (X=1, 0.75, 0.5, 0.25 and 0) mixed crystal has been grown by the Czochralski method. The segregation coefficient of In was studied by the inductively coupled plasma atomic emission spectrometry (ICP-OES). The crystal structure has been determined using X-ray diffraction (XRD) analysis. The thermoluminescence (TL) characterization of KClXBr1-X mixed crystals, exposed to gamma radiation has been performed. The results show the introduction of the dopants ions induced changes in the TL glow curve structure. The TL results suggest that doped KClXBr1-X mixed crystal has good potential active dosimeter applications for gamma ray irradiation.

Rezaee Ebrahim Saraee, Kh.; Hosseini, S. A.; Faripour, H.; Faiez, M. R.; Abdi, M. R.; Soltani, N.; Aghay Khareiky, A.

2014-09-01

277

Pipe corrosion and deposit study using neutron- and gamma- radiation sources  

NASA Astrophysics Data System (ADS)

The problems of corrosion and deposit are crucial issues in the pipelines of the chemical, nuclear and petrochemical industries. Radiography (neutron, gamma, X-ray) has long been used as a technique for pipe inspection and corrosion monitoring. The 10 MW Budapest research reactor site is a source of various energy neutron (thermal and epithermal) and gamma radiation. The detector system was a Peltier-cooled LLL CCD camera controlled by a PC with Image ProLite software and imaging plate equipment with a BAS 2500 scanner that used AIDA software. The objects inspected were corroded tubes and various kinds of test specimens with a large wall thickness (25 mm) inside and outside steps. In the evaluation part we used tomographic algorithms. A software simulation study was made as well. Fan-beam projections were computed of the given software phantoms and a new discrete tomography method was used to reconstruct the unknown objects from these projections.

Balaskó, Márton; Sváb, Erzsébet; Kuba, Attila; Kiss, Zoltán; Rodek, Lajos; Nagy, Antal

2005-04-01

278

Health effects of low level radiation: carcinogenesis, teratogenesis, and mutagenesis  

SciTech Connect

The carcinogenic effects of radiation have been demonstrated at high dose levels. At low dose levels, such as those encountered in medical diagnosis, the magnitude of the effect is more difficult to quantify. Three reasons for this difficulty are (1) the effects in human populations are small compared with the natural incidence of cancer in the populations; (2) it is difficult to transfer results obtained in animal studies to the human experience; and (3) the effects of latency period and plateau increase the complexity of population studies. In spite of these difficulties, epidemiologic studies of human populations exposed to low levels of radiation still play a valuable role in the determination of radiation carcinogenecity. They serve to provide upper estimates of risk and to rule out the appearance of new effects that may be masked by the effects of high doses. While there is evidence for mutagenic effects of radiation in experimental animals, no conclusive human data exist at the present. It is not possible to rule out the presence of genetic effects of radiation in humans, however, because many problems exist with regard to the epidemiologic detection of small effects when the natural incidence is relatively large. In animals, subtle effects (eg, a decrease in the probability of survival from egg to adult) may occur with greater frequency than more dramatic disorders in irradiated populations. However, these types of genetic abnormalities are difficult to quantitate. Current risk estimates are based primarily upon data pertaining to dominant mutations in rodents. Some specific locus studies also permit identification of recessive mutation rates. The embryo and fetus are considered to be at greater risk for adverse effects of radiation than is the adult.

Ritenour, E.R.

1986-04-01

279

Statistical properties of radiation power levels from a high-gain free-electron laser at and beyond saturation  

SciTech Connect

We investigate the statistical properties (e.g., shot-to-shot power fluctuations) of the radiation from a high-gain free-electron laser (FEL) operating in the nonlinear regime. We consider the case of an FEL amplifier reaching saturation whose shot-to-shot fluctuations in input radiation power follow a gamma distribution. We analyze the corresponding output power fluctuations at and beyond first saturation, including beam energy spread effects, and find that there are well-characterized values of undulator length for which the fluctuation level reaches a minimum.

Schroeder, Carl B.; Fawley, William M.; Esarey, Eric

2002-09-24

280

Combined effects of gamma-radiation and ethylene oxide in human diploid fibroblasts.  

PubMed

Human diploid VH-10 fibroblasts were pre-exposed to gamma-rays and then treated with ethylene oxide (EtO). In the reverse experiment, the cells were pretreated with EtO and then exposed to gamma-rays. Two different dose rates of gamma-rays were used: a low dose rate (LDR, 0.66 Gy/min) and a high dose rate (HDR, 10 Gy/min). Cell killing, mutagenicity and DNA double-strand breakage were studied in both types of experiment. The induction of mutations in the HPRT locus was studied by selection in medium containing 6-thioguanine. DNA double-strand breakage, measured as fraction of activity released (FAR), was investigated using pulsed field gel electrophoresis. Concerning mutagenesis, it was found that pre-exposure of the cells to gamma-radiation (1 Gy) followed by treatment with EtO (2.5 mMh) led to an additive co-interaction, irrespective of dose rate. On the other hand, the reverse experimental procedure (pretreatment with EtO followed by gamma-ray exposure) resulted in an antagonistic effect, which was most pronounced when the HDR was applied. In the latter case, the resultant mutant frequency was two times lower than the sum of the mutant frequencies after the individual treatments. However, the effect of the combined treatment on FAR was different: FAR increased with both combinations of agents used compared with the separate and hypothetically expected effects. Moreover, the HDR exposure led to an additional increase in FAR compared with the LDR one. PMID:10719032

Kolman, A; Chovanec, M

2000-03-01

281

Spirosoma radiotolerans sp. nov., a gamma-radiation-resistant bacterium isolated from gamma ray-irradiated soil.  

PubMed

A Gram-negative, short-rod-shaped bacterial strain with gliding motility, designated as DG5A(T), was isolated from a rice field soil in South Korea. Phylogenic analysis using 16S rRNA gene sequence of the new isolate showed that strain DG5A(T) belong to the genus Spirosoma in the family Spirosomaceae, and the highest sequence similarities were 95.5 % with Spirosoma linguale DSM 74(T), 93.4 % with Spirosoma rigui WPCB118(T), 92.8 % with Spirosoma luteum SPM-10(T), 92.7 % with Spirosoma spitsbergense SPM-9(T), and 91.9 % with Spirosoma panaciterrae Gsoil 1519(T). Strain DG5A(T) revealed resistance to gamma and UV radiation. Chemotaxonomic data showed that the most abundant fatty acids were summed feature C(16:1) ?7c/C(16:1) ?6c (36.90 %), C(16:1) ?5c (29.55 %), and iso-C(15:0) (14.78 %), and the major polar lipid was phosphatidylethanolamine (PE). The DNA G+C content of strain DG5A(T) was 49.1 mol%. Together, the phenotypic, phylogenetic, and chemotaxonomic data supported that strain DG5A(T) presents a novel species of the genus Spirosoma, for which the name Spirosoma radiotolerans sp. nov., is proposed. The type strain is DG5A(T) (=KCTC 32455(T) = JCM19447(T)). PMID:24748440

Lee, Jae-Jin; Srinivasan, Sathiyaraj; Lim, Sangyong; Joe, Minho; Im, Seonghun; Bae, So Il; Park, Kyoung Ryun; Han, Ji-Hee; Park, Se-Hee; Joo, Bo-Min; Park, Sol-Ji; Kim, Myung Kyum

2014-09-01

282

Gamma  

NSDL National Science Digital Library

The Geometric Algorithms for Modeling, Motion, and Animation (GAMMA) research group is part of the Department of Computer Science at the University of North Carolina. Some of the topics of research include haptics, "robot motion planning," collision detection, and "real-time interaction with virtual environments." There are several projects that are described in detail for each of the main areas of investigation. Many recent papers are offered that describe the progress and findings of the group's research. Additionally, there is a large collection of videos demonstrating computer animation, simulation, and interactive applications. Some software can also be downloaded for the GAMMA Web site; however, access to a few of the titles must first be approved by the system administrator.

2007-07-28

283

TETRA Observation of Gamma Rays at Ground Level Associated with Nearby Thunderstorms  

E-print Network

Terrestrial Gamma ray Flashes (TGFs) -- very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms -- have been detected with satellite instruments. TETRA, an array of NaI(Tl) scintillators at Louisiana State University, has now been used to detect similar bursts of 50 keV to over 2 MeV gamma rays at ground level. After 2.6 years of observation, twenty-four events with durations 0.02- 4.2 msec have been detected associated with nearby lightning, three of them coincident events observed by detectors separated by ~1000 m. Nine of the events occurred within 6 msec and 3 miles of negative polarity cloud-to-ground lightning strokes with measured currents in excess of 20 kA. The events reported here constitute the first catalog of TGFs observed at ground level in close proximity to the acceleration site.

Ringuette, Rebecca; Cherry, Michael L; Granger, Douglas; Guzik, T Gregory; Stewart, Michael; Wefel, John P

2013-01-01

284

Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector  

E-print Network

Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

K. Karafasoulis; K. Zachariadou; S. Seferlis; I. Papadakis; D. Loukas; C. Lambropoulos; C. Potiriadis

2010-11-15

285

QCD Corrections to the Radiative Decay B -> X_s gamma  

E-print Network

In this short review, the calculation of the next-to-next-to-leading order QCD corrections to the inclusive radiative decay B -> X_s gamma is described. I summarize the salient features of the calculational framework adopted, discuss the results obtained in the last few years, and indicate the technical tools that made the NNLO calculations possible. I conclude by comparing the current NNLO theoretical estimate for the branching ratio with the experimental measurement and by briefly discussing the size and origin of the residual theoretical uncertainty.

Andrea Ferroglia

2008-11-29

286

The use of gamma radiation for the elimination of Salmonella from frozen meat  

PubMed Central

The use of a gamma radiation process for the elimination of Salmonella from frozen meat is considered with particular reference to the treatment of boned-out horsemeat and kangaroo meat imported into the UK and intended for use as pet meat. Examination of dose/survival curves produced for several serotypes of Salmonella in frozen meat shows that a radiation dose of 0·6 Mrad. will reduce a population by at least a factor of 105. The influence on the radiation resistance of salmonellas of such factors as preirradiation growth in the meat and temperature during irradiation have been examined and considered. It is also demonstrated with both preinoculated and naturally contaminated meat that postirradiation storage in the frozen state does not lead to the revival of irradiated salmonellas. The properties of Salmonella survivors deliberately produced in meat using conditions of irradiation designed to simulate a commercial process are studied after six recycling treatments through the process. There were no important changes in characteristics normally used for identification of Salmonella but radiation resistance was lowered. Survivors grown in situ in meat after irradiation showed an abnormally long lag phase, and removal of competitive microflora in meat by the radiation treatment can influence the growth of salmonellas. PMID:4914090

Ley, F. J.; Kennedy, T. S.; Kawashima, K.; Roberts, Diane; Hobbs, Betty C.

1970-01-01

287

Effect of Meteorological Phenomena in Measures of Background Radiation X and Gamma Rays in São José dos Campos, SP, Brazil  

NASA Astrophysics Data System (ADS)

The objective of this work was to perform a study on the influence of meteorological phenomena on the background radiation X and gamma rays in São José dos Campos, SP, Brazil on the last three years. For this, we performed the monitoring of the integrated radiations and also of the main meteorological parameters (rainfall, relative humidity, temperature and pressure) daily without interruptions and time resolution of one minute. Measurements of X and gamma radiation in the range of energies from 30 keV to 10 MeV, were carried out using a scintillator crystal of sodium iodide activated with Tallium [NaI(Tl)] coupled to a photomultiplier, with energy resolution of 15%. Rainfall, atmospheric pressure, temperature, and relative humidity were recorded using sensors coupled to a five-channel specific data logger. By correlating the data from the measurements of intensity of X and gamma radiations with the meteorological parameters, it was found that atmospheric precipitation with or without electric discharges phenomenon that was affected more in the spectrum of background radiation profile. Some of the reasons why these changes occur in the background profile are due the presence of environmental radon gas that is drawn to the surface during the occurrences of local rainfall. During dry periods, the spectra of X and gamma radiations showed a daily cycle (24 hour). In relation to relative humidity, temperature and pressure, it was found that these parameters had negligible influence on the profile changes of the background radiation in São José dos Campos, SP, Brazil.

Gomes, Marcelo; Spjeldvik, Walther; Gusev, Anatoly; Alves, Mauro; Martin, Inacio; Pinto, Marcos; Ferro, Marco A.; Concei, Flavio

288

Effects of Dietary Iron and Gamma Radiation on the Rat Retina  

NASA Technical Reports Server (NTRS)

A health risk of concern for NASA relates to radiation exposure and its synergistic effects with other space environmental factors, includi ng nutritional status of the crew. Astronauts consume almost three times the recommended daily allowance of iron due to the use of fortifie d foods aboard the International Space Station, with iron intake occa sionally exceeding six times the recommended values. Recently, NASA has become concerned with visual changes associated with spaceflight, a nd research is being conducted to elucidate the etiology of eye structure alterations in the spaceflight environment. Terrestrially, iron o verload is also associated with certain optic neuropathies. In additi on, due to its role in Fenton reactions, iron can potentiate oxidative stress, which is a recognized cause of cataract formation. As part o f a study investigating the combined effects of radiation exposure an d iron overload on multiple physiological systems, we focused on defining the effects of both treatments on eye biology. In this study, 12- week-old Sprague-Dawley rats were assigned to one of four experimental groups: normal iron/no radiation (Control/Sham), high iron/no radiat ion (Fe/Sham), normal iron/gamma radiation (3 Gy cumulative dose, fra ctionated at 0.375 Gy/d every other day for 16 d) (Control/Rad), and high iron/gamma radiation (Fe/Rad). Oxidative stress-induced DNA damag e, measured as concentration of the marker 8-hydroxy-2'-deoxyguanosine (8OHdG) in eye retinal tissue by enzyme-immunoanalysis did not show significant changes among treatments. However, there was an overall i ncrease in 8OHdG immunostaining density in retina sections due to radiation exposure (P = 0.05). Increased dietary iron and radiation expos ure had an interactive effect (P = 0.02) on 8OHdG immunostaining of t he retinal ganglion cell layer with iron diet increasing the signal in the group not exposed to radiation (P = 0.05). qPCR gene expression profiling of relevant target genes indicated upregulation of ferritin light chain (P = 0.09) as a result of dietary iron but no change in e xpression of the gene for ferritin heavy chain. Immunolocalization of light chain and heavy chain of the iron storage protein ferritin showed the expected distribution in the choroid, photoreceptor layer, inn er nuclear layer and in the inner plexiform layer that corresponded t o the synaptic terminals of bipolar cells. Evidence of stress and damage in the retina was also suggested by a decrease in expression of th e survival marker Bcl2 (P = 0.01) and the protective proteins clusterin (P = 0.04) and heat shock factor 1 (Hsf1, P < 0.001), as a result o f increased dietary iron. The effect of increased iron on expression of the antioxidant enzyme heme oxygenase 1 (Hmox1) had a significant interaction with the effect of radiation (P < 0.001). In summary, the results of this study indicate that both gamma radiation exposure and a moderate increase in dietary iron can contribute to deleterious cha nges in retinal health and physiology.

Morgan, Jennifer; Marshall, Grace; Theriot, Corey A.; Chacon, Natalia; Zwart, Sara; Zanello, Susana B.

2012-01-01

289

Results of calculations of external gamma-radiation exposure rates from fallout and the related radionuclide compositions. Operations Nougat through Bowline, 1962-1968  

SciTech Connect

Data are presented on calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from Events that deposited detectable radioactivity outside the Nevada Test Site complex.

Hicks, H.G.

1981-07-01

290

Results of calculations of external gamma-radiation exposure rates from fallout and the related radionuclide compositions. Operations Nougat through Bowline, 1962-1968  

Microsoft Academic Search

Data are presented on calculated gamma radiation exposure rates and ground deposition of related radionuclides resulting from Events that deposited detectable radioactivity outside the Nevada Test Site complex.

Hicks

1981-01-01

291

Death of a classified worker probably caused by overexposure to gamma radiation.  

PubMed Central

This paper describes the case of an industrial radiographer who was seriously overexposed to gamma radiation. The exact circumstances of this exposure were not established but it was concluded that he was repeatedly irradiated probably to a total average whole body dose of at least 10 Gy over several years. Also, a much larger dose to a hand required its partial amputation. He developed myelodysplasia, which progressed to acute myeloid leukaemia from which he died. Karyotypic examination of the leukaemic blasts showed changes very similar to those associated with secondary leukaemia that may develop after radio or chemotherapy. The paper describes his medical case history, the investigation of his workplace, and the attempts to estimate his radiation dose by chromosomal analysis of blood lymphocytes and electron spin resonance of dental enamel and bone. Images Figure 1 Figure 2 PMID:8000499

Lloyd, D C; Edwards, A A; Fitzsimons, E J; Evans, C D; Railton, R; Jeffrey, P; Williams, T G; White, A D; Ikeya, M; Sumitomo, H

1994-01-01

292

Radiative B Meson Decay as a Probe of Physics Beyond the Standard Model: Time-Dependent CP Violation in B0 --> KS pi0 gamma and the B --> phi K gamma Branching Fraction  

SciTech Connect

The author presents measurements of radiative B meson decays to the final states K{sub s}{sup 0}{pi}{sup 0}{gamma} and K{phi}{gamma} based on data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. In a data sample of 467 million B{bar B} pairs, the time-dependent CP asymmetry in B{sup 0} {yields} K{sub s}{sup 0}{pi}{sup 0}{gamma} decays is measured in two regions of K{sub s}{sup 0}-{pi}{sup 0} invariant mass. In the K* region, 0.8 < m(K{sub s}{sup 0}{pi}{sup 0}) < 1.0 GeV/c{sup 2}, we find S{sub K*{gamma}} = -0.03 {+-} 0.29 {+-} 0.03 and C{sub K*{gamma}} = -0.14 {+-} 0.16 {+-} 0.03; in the range 1.1 < m(K{sub s}{sup 0}{pi}{sup 0}) < 1.8 GeV/c{sup 2}, they find S{sub K{sub s}{sup 0}{pi}{sup 0}{gamma}} = -0.78 {+-} 0.59 {+-} 0.09 and C{sub K{sub s}{sup 0}{pi}{sup 0}{gamma}} = -0.36 {+-} 0.33 {+-} 0.04. With a sample of 228 million B{bar B} pairs they measure the branching fraction {Beta}(B{sup +} {yields} K{sup +}{phi}{gamma}) = (3.5 {+-} 0.6 {+-} 0.4) x 10{sup -6} and set the limit {Beta}(B{sup 0} {yields} K{sup 0}{phi}{gamma}) < 2.7 x 10{sup -6} at 90% confidence level. The direct CP asymmetry in B{sup +} {yields} K{sup +}{phi}{gamma} is found to be A{sub CP} = (-26 {+-} 14 {+-} 5)%. In each case the uncertainties are statistical and systematic, respectively.

Tuggle, Joseph Marion, IV; /Maryland U.

2009-01-22

293

Radiative $\\Omega_{Q}^{*}\\rightarrow\\Omega_{Q}\\gamma$ and $\\Xi_{Q}^{*}\\rightarrow\\Xi^{\\prime}_{Q}\\gamma$ transitions in light cone QCD  

E-print Network

We calculate the magnetic dipole and electric quadrupole moments associated with the radiative $\\Omega_{Q}^{*}\\rightarrow\\Omega_{Q}\\gamma$ and $\\Xi_{Q}^{*}\\rightarrow\\Xi^{\\prime}_{Q}\\gamma$ transitions with $Q=b$ or $c$ in the framework of light cone QCD sum rules. It is found that the corresponding quadrupole moments are negligibly small while the magnetic dipole moments are considerably large. A comparison of the results on the considered multipole moments as well as corresponding decay widths with the predictions of the vector dominance model is performed.

Aliev, T M; Sundu, H

2014-01-01

294

Radiation-induced oxidative degradation of poly(vinyl chloride). [Gamma radiation  

SciTech Connect

Gas evolution and oxygen consumption in the ..gamma..-irradiation of PVC were studied. The gas evolution and the oxidative degradation are retarded by the presence of plasticizers and stabilizers. The G(HCl) and G(H/sub 2/) are 8 and 0.24 for the irradiation of pure PVC under vacuum and 0.02 and 0.14 for that of plasticized PVC, respectively. Gas evolution increases in the presence of oxygen, specially for the pure PVC. The G(-O/sub 2/) values for the pure and plasticized PVC are 30 and 12, respectively. The dependence of gas evolution and oxygen consumption on the oxygen pressure is more pronounced for the plasticized PVC than pure PVC because the oxygen diffusion is controlled.

Hegazy, E.S.A.; Seguchi, T.; Machi, S.

1981-09-01

295

Modulation phenomena in Si nanowire field-effect transistors characterized using noise spectroscopy and gamma radiation technique  

NASA Astrophysics Data System (ADS)

High-quality silicon nanowire (NW) field-effect transistors (FETs) were designed and fabricated. Features of transport and modulation phenomena of the structures were studied using a number of techniques, including noise spectroscopy. Using the 1/f noise component level, the values of the volume trap densities in gate dielectric are estimated to be around 1 × 1017 cm-3 eV-1. This result proves high quality of the investigated structures. Analysis of Lorentzian noise components of NW samples is used to characterize single trap and its parameters. A strong modulation of carrier concentration in the conducting channel under influence of even single carrier capture event has been revealed. Possibility of fine tuning of the transport properties of the sample with low-dose gamma irradiation has been shown. The gamma radiation treatment of the NW samples was applied as an effective technique to confirm the strong influence of trap charges on conductivity behavior in the channel of NW FETs. The results demonstrate that the modulation effects at the nanoscale enable effective changing of the channel conductivity by single capture events and thus are promising for future information technologies and ultra-sensitive single-molecular sensor applications.

Pud, S.; Li, J.; Petrychuk, M.; Feste, S.; Vitusevich, S.; Danilchenko, B.; Offenhäusser, A.; Mantl, S.

2013-03-01

296

Inhibition of vascular cell growth by X-ray irradiation: comparison with gamma radiation and mechanism of action  

Microsoft Academic Search

Purpose: Catheter-based delivery of gamma and beta radiation effectively inhibits restenosis. Major disadvantages of these radioisotopes include continuous emission; excessive depth of penetration, creating safety hazards (gamma); and inadequate penetration, limiting effectiveness (beta). Low-voltage X-rays have a distinct potential advantage, because the source is active only when current is applied, and depth of penetration is voltage dependent. This study was

Neal A Scott; Ian R Crocker; QiQin Yin M. S; Dan Sorescu; Josiah N Wilcox; Kathy K Griendling

2001-01-01

297

Cold neutron prompt gamma activation analysis, a non-destructive technique for hydrogen level assessment in zirconium alloys  

E-print Network

Cold neutron prompt gamma activation analysis, a non-destructive technique for hydrogen level to quantitatively assess hydrogen concentration in zirconium alloys. The technique, called Cold Neutron Prompt Gamma to a neutron source such as the one at the National Institute of Technology (NIST) Center for Neutron Research

Motta, Arthur T.

298

Calculations of radiation levels during reactor operations for safeguard inspections  

NASA Astrophysics Data System (ADS)

It is necessary to calculate the total level of radioactivity produced by the reactor operation when the reactor cover is opened during periodical safeguard inspections for safety requirements. Also the calculations are performed for different reactor core and spent fuel storage loadings during refuelling after reactor shutdown. When an internal core spent fuel storage is used in the shield tank to accommodate a large number of spent fuel baskets, physical calculations are performed to determine the number of these spent fuel elements which can be accommodated and still maintain the gamma activity outside under the permissible limit. The corresponding reactor power level is determined. The radioactivity calculations are performed for this internal storage at different axial levels to avoid the criticality of the reactor core. Transport theory is used in calculations based on collision probability for multi group cell calculations. Diffusion theory is used in three dimensions in the core calculations. The nuclear fuel history is traced and radioactive decay is calculated, since reactor fission products are very sensitive to power level. The radioactivity is calculated with a developed formula based on fuel basket loading integrity.

Sobhy, M.

1996-05-01

299

Single-source gamma radiation procedures for improved calibration and measurements in porous media  

SciTech Connect

When dual-energy gamma radiation systems are employed for measurements in porous media, count rates from both sources are often used to compute parameter values. However, for several applications, the count rates of just one source are insufficient. These applications include the determination of volumetric liquid content values in two-liquid systems and salt concentration values in water-saturated porous media. Single-energy gamma radiation procedures for three applications are described in this paper. Through an error analysis, single-source procedures are shown to reduce the probable error in the determinations considerably. Example calculations and simple column experiments were conducted for each application to compare the performance of the new single-source and standard dual-source methods. In all cases, the single-source methods provided more reliable data than the traditional dual-source methods. In addition, a single-source calibration procedure is proposed to determine incident count rates indirectly. This procedure, which requires packing under saturated conditions, can be used in all single- and dual-source applications and yields accurate porosity and dry bulk density values.

Oostrom, M. [Pacific Northwest National Lab., Richland, WA (United States). Environmental Technology Div.] [Pacific Northwest National Lab., Richland, WA (United States). Environmental Technology Div.; Hofstee, C.; Dane, H. [Auburn Univ., AL (United States). Dept. of Agronomy and Soils] [Auburn Univ., AL (United States). Dept. of Agronomy and Soils; Lenhard, R.J. [Sultan Oaboos Univ. (Oman). Dept. of Soil and Water] [Sultan Oaboos Univ. (Oman). Dept. of Soil and Water

1998-08-01

300

Gamma radiation consequences on desert locust Schistocerca gregaria (Forsk.) digestive system.  

PubMed

Schistocera gregaria (Forsk.) (Orthoptera, Acrididae) remains a major insect pest in Africa, more particularly in the Sahelian zone. Present control methods are only partially efficient. In a previous study, we tested the potentiality of a sterile insect technique (SIT). Males of S. gregaria appeared to be much radiosensitive as already a dose of 3 Gy limited their survival. Gamma-radiations are known to damages the epithelial tissue of midgut, which affects the alimentation in insects. In this work, we show how digestive system of S. gregaria males is affected when submitted to a dose of 4 gamma rays. Nutrition is affected as males stop feeding soon after irradiation and progressively lose weight. Histological analyses on the midgut showed important epithelium damages. The regenerative cells by which the epithelial cells are replaced were damaged on the first days following irradiation. Consequently, regenerative cells are unable to divide and replace the normal loss of midgut cell. After nine days, the entire midgut epithelium was destroyed and only longitudinal muscles layer remained intact. This indicates that low radiation doses should be used if SIT will be applied. PMID:21539264

Dushimirimana, S; Muratori, F; Damiens, D; Hance, T

2010-01-01

301

Radiation degradation of polystyrene\\/poly(methyl methacrylate) blends. [Gamma radiation  

Microsoft Academic Search

Although copolymers of styrene(PS) and methyl methylacrylate(PMMA) showed slightly higher flexural strengths than the homopolymers, blends showed markedly lower strengths, the decrease being greatest at ca 50% styrene. There was a decrease in modulus, but an increase in the elongation to break attributable to the two-phase morphology. The effect of various radiation doses on flexural strength is demonstrated. The decreases

R. W. Garrett; J. H. ODonnell; P. J. Pomery; E. C. Shum

1979-01-01

302

Gamma radiation roused lattice contraction effects investigated by Mössbauer spectroscopy in nanoparticle Mn-Zn ferrite  

NASA Astrophysics Data System (ADS)

Nanopowders of MnxZn1-xFe2O4 with x=0.4, 0.5 and 0.6 were synthesized using a combustion synthesis method. X-ray diffraction (XRD) patterns obtained on samples confirmed formation of monophasic cubic phase material. Lattice parameters and X-ray densities were obtained from rietvield refinement of the XRD patterns. All samples were radiated with gamma radiation with a dose of 200 Gy obtained from 60Co source. Structural and physical parameters, such as lattice constant, X-ray density and particle size, determined for as prepared samples (SA) and gamma irradiated samples (SR), showed extraordinary variations in their values. Saturation magnetizations (MS), remnant magnetization (MR) and coercive field (HC) for both sets of samples illustrated an enhancement in their values for SR samples. Investigations were carried out using Mössbauer spectroscopy to divulge structural and magnetic information of all samples. Room temperature Mössbauer spectra were fitted with five magnetic sextets and a symmetric paramagnetic doublet for the data obtained on samples except for x=0.4, SA sample. The presence of well defined doublets in the spectra of SA and SR samples is attributes of superparamagnetism, indicating the reduction in A-B superexchange interaction due to dilution of sub-lattice by Zn ions. Cation distribution at A site and B site, estimated from Mössbauer data exhibited amazing alterations which were highly stable. The variations in physical, structural and magnetic properties observed are attributed to change of Fe2+/Fe3+ and Mn+2/Mn+3 ratios in gamma-irradiated samples.

Naik, P. P.; Tangsali, R. B.; Meena, S. S.; Bhatt, Pramod; Sonaye, B.; Sugur, S.

2014-09-01

303

Examination of level density prescriptions in the interpretation of high energy gamma-ray spectra  

E-print Network

High energy $\\gamma$-ray spectra measured by our group involving the compound nuclei (CN) $^{63}$Cu at excitation energy ($E^*$) $\\sim$ 36 MeV with average angular momentum ($J$) = 12 - 17 $\\hbar$, $^{97}$Tc at $E^* \\sim$ 29 - 50 MeV with $J$ = 12 - 14 $\\hbar$, $^{113}$Sb at $E^*$ = 109 MeV and 121 MeV with $J$ = 49 - 59 $\\hbar$ and $^{201}$Tl at $E^*$ = 39.5, 47.5 MeV with $J$ = 18 - 24 $\\hbar$ have been analyzed utilizing the level density prescriptions of (i)Ignatyuk, Smirenkin and Tishin (IST), (ii)Budtz-Jorgensen and Knitter (BJK), and (iii) Kataria, Ramamurthy and Kapoor (KRK). These three prescriptions have been tested for correct statistical model description of high energy $\\gamma$-rays in the light of extracting the giant dipole resonance (GDR) parameters at low excitation energy and spin where shell effects might play an important role as well as at high excitation energy where shell effects have melted. Interestingly, only the IST level density prescription could explain the high energy $\\gamma$-r...

Bhattacharya, Srijit; Dey, Balaram; Mondal, Debasish; Mukhopadhyay, S; Pal, Surajit; De, A; Banerjee, S R

2014-01-01

304

Radiation exposure levels within timber industries in Calabar, Nigeria  

PubMed Central

The UNSCEAR (2000) observed that there could be some exposure at work which would require regulatory control but is not really considered. This study was, therefore, set up to evaluate the effective dose in timber industries in Calabar, Nigeria to determine if the evaluated dose levels could lead to any radiological health effect in the workers, and also determine if the industries require regulatory control. The gamma ray exposure at four timber industries measured using an exposure meter were converted to effective dose and compared with the public and occupational values. The evaluated effective dose values in the timber industries were below public and occupational exposure limits and may not necessarily result in any radiological health hazard. Therefore, they may not require regulatory control. PMID:20098544

Inyang, S. O.; Inyang, I. S.; Egbe, N. O.

2009-01-01

305

SOLIDIFICATION TESTING FOR A HIGH ACTIVITY WASTESTREAM FROM THE SAVANNAH RIVER SITE USING GROUT AND GAMMA RADIATION SHEILDING MATERIALS - 10017  

SciTech Connect

The U.S. Department of Energy (DOE) tasked MSE Technology Applications, Inc. (MSE) with evaluating grouts that include gamma radiation shielding materials to solidify surrogates of liquid aqueous radioactive wastes from across the DOE Complex. The Savannah River Site (SRS) identified a High Activity Waste (HAW) that will be treated and solidified at the Waste Solidification Building (WSB) for surrogate grout testing. The HAW, which is produced at the Mixed Oxide Fuel Fabrication Facility (MFFF), is an acidic aqueous wastestream generated by the alkaline treatment process and the aqueous purification process. The HAW surrogate was solidified using Portland cement with and without the inclusion of different gamma radiation shielding materials to determine the shielding material that is the most effective to attenuate gamma radiation for this application.

Burns, H.

2009-11-10

306

Synergistic effects in the short-term preservation of hides with antiseptics and gamma radiation  

NASA Astrophysics Data System (ADS)

The normal time lapse between the skinning and tanning processes of green hides necessitates the need for a short-term preservation technique to be employed. The most common method of bringing about such preservation is the coarse salting of the flesh side of hides. More recently the antiseptic treatment of hides was introduced to overcome the serious environmental pollution brought about by the salting process. The antiseptic treatment, however, must also be carefully controlled to avoid upsetting the biological breakdown processes in effluent plants. The gamma sterilization of such hides presents a non-polluting alternative to these methods. As the nature of this product demands excessively high radiation doses to be effective, which negatively influences the economics of the process and the physical properties of the resultant leather, a combination process employing radiation and antiseptics was investigated. It was observed that the radiation dose could be lowered from 50 kGy to 8 kGy in combination with certain antiseptics, whilst the required antiseptic concentration could be substantially lowered in the presence of radiation. The resultant leather was of an excellent quality whilst minimizing the environmental pollution problem.

Du Plessis, TA; Russell, AE; Stevens, RCB; Galloway, AC

307

Well Ge and semi-planar Ge (HP) detectors for low-level gamma-spectrometry  

NASA Astrophysics Data System (ADS)

Two gamma spectrometers, a well Ge and a semi-planar Ge (HP), are now installed and calibrated for measurements of environmental radioactivity with special attention being paid to the requirements needed for aquatic mass-balance studies, including isotope-particle dynamics and dating of recent deposits. These facilities will complement the previously developed isotope dilution alpha spectrometry (PIPS detectors) and radon emanation (ionization chambers) techniques for 210Pb dating. A careful evaluation of efficiencies and background of the Ge detectors, together with the influence of the sample's intrinsic activity on the lower limit of detection (LLD), allowed us to study the relative importance of detector and shield specifications on low level gamma spectrometry of environmental samples with various sizes and composition.

El-Daoushy, F.; Garcia-Tenorio, R.

1995-02-01

308

Energy Levels and Radiative Rates in Al-Like Copper  

NASA Astrophysics Data System (ADS)

Excitation energies from ground state for 98 fine-structure levels and oscillator strengths and radiative decay rates for all electric-dipole-allowed and intercombination transitions among the fine-structure levels of the terms belonging to the (1s^22s^22p^6)3s^23p, 3s3p^2, 3s^23d, 3p^3, 3s3p3d, 3p^23d, 3s3d^2, 3s^24s, 3s^24p, 3s^24d, 3s^24f, and 3s3p4s configurations of Cu XVII, are calculated using extensive CI wave functions [1]. The important relativistic effects in intermediate coupling are incorporated through the Breit-Pauli Hamiltonian. We have also investigated the effects of electron correlations on our calculated data, particularly on the intercombination transitions, by including orbitals with up to n=5, considering up to three electron excitations from the valence electrons of the basic configurations and including a large number of configurations. Our adjusted excitation energies are in excellent agreement with experimental results [2]. We find enormous mixing among several fine-structure levels, making it very difficult to identify them correctly. Our radiative lifetimes of the fine-structure levels agree excellently with those of Ref. [3]. 1. A. Hibbert, Comput. Phys. Commun. 9, 141 (1975). 2. T. Shirai et al., J. Phys. Chem. Ref. Data 20, 12 (1991). 3. E. Trabert et al., J. Opt. Soc. Am. B 5, 2173 (1988)

Gupta, G. P.; Msezane, A. Z.

2007-06-01

309

Radiation-initiated emulsion copolymerization of styrene and carboxylic acid monomers. [Gamma radiation  

SciTech Connect

The emulsion copolymerization of styrene and carboxylic acid monomers such as acrylic, methacrylic, and itaconic acids (AAc, MAAc, IAc) was studied by using /sup 60/Co ..gamma..-rays as initiator and sodium dodecylsulfate as emulsifier. The polymerization behavior of these acid monomers was followed by simultaneous conductometric and potentiometric titrations for a latex sample taken in polymerization. The polymerization rate of these acid monomers increases in the following order of hydrophobicity: IAc < AAc < MAAc; this suggests that their polymerization sites are mainly the surface and/or subsurface regions of latex particles. The copolymerization rate of styrene and acid monomer increases with an increase in the acid monomer content for AAc and MAAc, whereas for IAc the rate decreases. The particle sizes determined by the stopped-flow method reveal that this variation of copolymerization rate cannot be explained by the number of growing particles and should be attributed to another factor; for instance, the transfer rate of styrene molecules from oil droplets to growing particles.

Egusa, S.; Makuuchi, K.

1982-03-01

310

Design and Testing of a Novel Wide Range - Segmented Gamma Scanner Incorporating Tomographic Gamma Scanning for Measuring Both Low and Intermediate Level Waste in Drums - 13470  

SciTech Connect

This paper describes the design and testing of a novel automated Wide Range Segmented Gamma ray Scanning (WR-SGS) assay instrument that also incorporates Tomographic Gamma Scanning (TGS). The instrument is designed for the measurement of both Low and Intermediate Level Waste (LLW and ILW) in 200 litre drums and other waste containers covering a wide range of density. Like earlier ANTECH WR-SGS instruments, the system employs a single shielded and collimated high purity germanium (HPGe) detector to quantify the radionuclide content of the waste and like conventional SGS instruments it is suitable for the measurement of relatively homogeneous waste matrices. Also, like earlier WR-SGS systems the instrument incorporates an automated variable aperture collimator, which allows the vertical segment height to be adjusted in order to measure both high dose-rate and very low activity drums. The instrument employs both conventional discrete SGS vertical segment measurements as well as vertical segment measurement by continuous helical-scanning of the drum as it rotates. This latter method reduces measurement times for SGS measurements. In order to determine the density corrections for both low and high-density drums, a high activity Eu-152 transmission source is employed. When not in use, and in place of a conventional shutter mechanism, the shielded transmission source is moved to a shielded storage position to eliminate background radiation from the source. Due to its novel features, the WR-SGS is applicable to the measurement of both very low and very high activity waste drums as well as waste drums with a wide range of density. If located in a low background position and with the effective shielding of the strong transmission source, the instrument can be used to measure very low level or exempt waste. In order to extend the range of applicability to the measurement of heterogeneous drums, TGS measurement capability has been included in the basic WR-SGS design. This is achieved by adding horizontal motion to the waste drum rotation platform and incorporating TGS collimation into the variable aperture collimator, as well as a filter to reduce the detector signal when straight-through measurements are made using the strong transmission source. Test measurements are presented of the system operating in both SGS and TGS modes using different drum densities and source strengths. The test measurement results are compared with benchmarked MCNP Monte Carlo calculations. The Wide Range SGS - TGS instrument extends the range of both activity and density that can be measured in 200 and 340 litre drums. (authors)

Mason, John A.; Looman, Marc R.; Odell, Lawrence V.; Poundall, Adam J.; Towner, Antony C.N. [ANTECH, A. N. Technology Ltd., Unit 6, Thames Park, Wallingford, Oxfordshire, OX10 9TA (United Kingdom)] [ANTECH, A. N. Technology Ltd., Unit 6, Thames Park, Wallingford, Oxfordshire, OX10 9TA (United Kingdom); Hong, Dae-Seok; Jang, Won-Hyuk; Kwak, Kyung-Kil [Korea Atomic Energy Research Institute, 111, Daedoek-daero 989 beon-gil, Yuseong-gu, Daejeon (Korea, Republic of)] [Korea Atomic Energy Research Institute, 111, Daedoek-daero 989 beon-gil, Yuseong-gu, Daejeon (Korea, Republic of); Seo, Seung-Min [Young In Scientific Co. Ltd, 22, Apgujeong-ro 28 gil, Gangnam-gu, Seoul (Korea, Republic of)] [Young In Scientific Co. Ltd, 22, Apgujeong-ro 28 gil, Gangnam-gu, Seoul (Korea, Republic of); Piotrowski, Matt [ANTECH Corporation, 9050 Marshall Court, Westminster, CO, 80031 (United States)] [ANTECH Corporation, 9050 Marshall Court, Westminster, CO, 80031 (United States)

2013-07-01

311

Radiative Lifetimes for High Levels of Neutral Fe  

NASA Astrophysics Data System (ADS)

New radiative lifetime measurements for ~ 50 high lying levels of Fe I are reported. Laboratory astrophysics faces a challenge to provide basic spectroscopic data, especially reliable atomic transition probabilities, in the IR region for abundance studies. The availability of HgCdTe (HAWAII) detector arrays has opened IR spectral regions for extensive new spectroscopic studies. The SDSS III APOGEE project in the H-Band is an important example which will penetrate the dust obscuring the Galactic bulge. APOGEE will survey elemental abundances of 100,000 red giant stars in the bulge, bar, disk, and halo of the Milky Way. Many stellar spectra in the H-Band are, as expected, dominated by transitions of Fe I. Most of these IR transitions connect high levels of Fe. Our program has started an effort to meet this challenge with new radiative lifetime measurements on high lying levels of Fe I using time resolved laser induced fluorescence (TRLIF). The TRLIF method is typically accurate to 5% and is efficient. Our goal is to combine these accurate, absolute radiative lifetimes with emission branching fractions [1] to determine log(gf) values of the highest quality for Fe I lines in the UV, visible, and IR. This method was used very successfully by O’Brian et al. [2] on lower levels of Fe I. This method is still the best available for all but very simple spectra for which ab-initio theory is more accurate. Supported by NSF grant AST-0907732. [1] Branching fractions are being measured by M. Ruffoni and J. C. Pickering at Imperial College London. [2] O'Brian, T. R., Wickliffe, M. E., Lawler, J. E., Whaling, W., & Brault, J. W. 1991, J. Opt. Soc. Am. B 8, 1185

Lawler, James E.; Den Hartog, E.; Guzman, A.

2013-01-01

312

Effect of gamma radiation on selected functional and physical properties of liquid egg white  

E-print Network

. . . . . . 69 27 Regression coefficients of relative per cent concentration on cost-radiation frozen storage ~ . 84. xi LIST OF FIGURES FIGURE Page 1 Experimental design ~ ~ 5 2 Ef f ~ct of post-radiation frozen storage . . . . . . . . . 16 3... control. S. VS def ~ SoS ~ M. S, F Total Treat. l Re p. Rep. X Treat ~ Error 53 1 2 2 48 92. 50 1. 64. 15. 72 3 27 71. 87 1. 64 7. 86 1. 63 1. 4. 9 1. 10 5 2544 l. 09 **Significant at the 0. 01 level of probability. Treat. The radiation...

Ball, Hershell Ray

2012-06-07

313

Effects of gamma radiation on the dielectric and electro-optical properties of a polymer-dispersed liquid crystal  

NASA Astrophysics Data System (ADS)

We have investigated the effects of electric field and gamma radiation on the permittivity of a liquid crystal (E8), polymer-matrix (C135) and their composite polymer-dispersed liquid crystal (PDLC). The permittivity data are analyzed in terms of the Debye model, which provides insight into the effects of radiation-induced charges on the relaxation time constants. The effect of gamma-ray dose on the electro-optical response of the PDLC is studied by modeling PDLC as a composite material consisting of either isolated or interconnected liquid-crystal droplets embedded in a polymer matrix.

Sharma, Suresh C.; Ramsey, Robert A.

2010-01-01

314

Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes  

SciTech Connect

The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using an immortalized human WBC culture. Chromosomally visible lesions are scored on cells incubated for 2 h after irradiation in the presence and absence of 1.0 mg/ml of caffeine. An eightfold amplification of scorable lesions is achieved over the action of radiation alone. This approach provides a closer approximation to absolute mutagenicity unmitigated by repair processes, which can vary in different situations. It is proposed that mutagenesis testing of this kind, using caffiene or other repair-inhibitory agents, be employed to identify mutagens in their effective concentrations to which human populations may be exposed; to detect agents such as caffeine that may synergize mutagenic actions and pose epidemiologic threats; and to discover effective anti-mutagens. Information derived from the use of such procedures may help prevent cancer and newly acquired genetic disease.

Puck, T.P.; Johnson, R.; Waldren, C.A. (Eleanor Roosevelt Institute for Cancer Research, Denver, CO (United States)); Morse, H. (Univ. of Colorado Cancer Center, Denver, CO (United States))

1993-09-01

315

High energy gamma ray astronomy  

NASA Technical Reports Server (NTRS)

The SAS-2 gamma ray experiment and its detection of celestial gamma rays are described. Data also cover intensity of high energy gamma rays, gamma ray distribution, gamma ray origin, and diffuse radiation.

Fichtel, C. E.

1974-01-01

316

Elimination of radiation-induced {gamma}-H2AX foci in mammalian nucleus can occur by histone exchange  

SciTech Connect

Double-strand breaks in mammalian DNA lead to rapid phosphorylation of C-terminal serines in histone H2AX ({gamma}-H2AX) and formation of large nuclear {gamma}-H2AX foci. After DNA repair these foci disappear, but molecular mechanism of elimination of {gamma}-H2AX foci remains unclear. H2AX protein can be phosphorylated and dephosphorylated in vitro in the absence of chromatin. Here, we compared global exchange of GFP-H2AX with kinetics of formation and elimination of radiation-induced {gamma}-H2AX foci. Maximal number of {gamma}-H2AX foci is observed one hour after irradiation, when {approx}20% of GFP-H2AX is exchanged suggesting that formation of the foci mostly occurs by in situ H2AX phosphorylation. However, slow elimination of {gamma}-H2AX foci is weakly affected by an inhibitor of protein phosphatases calyculin A which is known as an agent suppressing dephosphorylation of {gamma}-H2AX. This indicates that elimination of {gamma}-H2AX foci may be independent of dephosphorylation of H2AX which can occur after its removal from the foci by exchange.

Svetlova, Maria [Institute of Cytology RAS, 194064 St. Petersburg (Russian Federation); Solovjeva, Liudmila [Institute of Cytology RAS, 194064 St. Petersburg (Russian Federation); Nishi, Kayoko [Department of Biochemistry and Molecular Medicine, University of California Medical School, Davis, CA 95616 (United States); Nazarov, Igor [Department of Biochemistry and Molecular Medicine, University of California Medical School, Davis, CA 95616 (United States); Siino, Joseph [Department of Microbiology, University of California, Davis, CA 95616 (United States); Tomilin, Nikolai [Institute of Cytology RAS, 194064 St. Petersburg (Russian Federation)]. E-mail: nvtom@mail.ru

2007-06-29

317

Low-level gamma spectrometry for pollution assessment in San Simón Bay (Vigo, Spain)  

NASA Astrophysics Data System (ADS)

A gamma spectrometer with HPGe detector of 50% relative efficiency and 1 cps total background has been dedicated to the measurement of an intertidal sediment core from a coastal environment at the Ría de Vigo (Spain). The area is affected by lead pollution and the source identification needs of a precise dating of the sediment core. Such a precise dating requires the measurement not only of the radionuclides directly involved in time calculation, as 210Pb and 226Ra, but also of ancillary radionuclides which inform about the dating model to apply and about the validity of its time estimation. Gamma spectrometry with Ge detectors performs a simultaneous measurement of the full content in ?-emitters of the sample. However, its use is limited by its high spectral background. We present the characteristics of our lowlevel background gamma spectrometer and also of Galea, the computing tool for the expert analysis of natural radionuclides. Both make possible to get the proper experimental results to reach a suitable dating. The results allowed us to detect a change in the sedimentation dynamics in the area under study, to verify the impact of lead pollution in the 210Pb level, to obtain a sedimentation rate by using the CF:CS model with a suitable correction factor and, finally, to validate the sediment dating.

Quintana, B.; Álvarez-Iglesias, P.; Santamaría, R.; Rubio, B.; Pérez-Arlucea, M.

2006-05-01

318

Mechanism of Action for Anti-radiation Vaccine in Reducing the Biological Impact of High-dose Gamma Irradiation  

NASA Technical Reports Server (NTRS)

Ionizing radiation is a major health risk of long-term space travel, the biological consequences of which include genetic and oxidative damage. In this study, we propose an original mechanism by which high doses of ionizing radiation induce acute toxicity. We identified biological components that appear in the lymphatic vessels shortly after gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then collected and circulated throughout the body via the lymph circulation and bloodstream. Depending on the type of SRD elicited, different syndromes of acute radiation sickness (ARS) were expressed. The SRDs were developed into a vaccine used to confer active immunity against acute radiation toxicity in immunologically naive animals. Animals that were pretreated with SRDs exhibited resistance to lethal doses of gamma radiation, as measured by increased survival times and survival rates. In comparison, untreated animals that were exposed to similar large doses of gamma radiation developed acute radiation sickness and died within days. This phenomenon was observed in a number of mammalian species. Initial analysis of the biochemical characteristics indicated that the SRDs were large molecular weight (200-250 kDa) molecules that were comprised of a mixture of protein, lipid, carbohydrate, and mineral. Further analysis is required to further identify the SRD molecules and the biological mechanism by which the mediate the toxicity associated with acute radiation sickness. By doing so, we may develop an effective specific immunoprophylaxis as a countermeasure against the acute effects of ionizing radiation.

Maliev, Vladislav; Popov, Dmitri; Jones, Jeffrey A.; Casey, Rachael C.

2007-01-01

319

Technologically enhanced levels of natural radioactivity studied by gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

The pollution of the environment arising from sources emitting preconcentrated natural radionuclides was studied using low-level gamma-spectrometry. Along the upper stream of the river Sava in Slovenia (Yugoslavia) many sources with enhanced concentrations of natural radionuclides contribute to the pollution of the river. The pollution of air is usually limited to the vicinity of the sources. A planar Ge(HP) detector with a large surface showed improved sensitivity for 210Pb, U, and Ra in comparison to the 116 cm 3 Ge(Li) coaxial detector.

Brajnik, D.; Kobal, I.; Korun, M.; Miklavži?, U.

1986-11-01

320

What Is The Optimal Level of Solar Radiation Management?  

NASA Astrophysics Data System (ADS)

Solar radiation management (SRM), achieved by stratospheric aerosol injections or by placing a sunshade in orbit, has the potential to cool the Earth's climate to pre-industrial temperatures even with large quantities of CO2 in the atmosphere. Many authors have observed that in such a geoengineered world there would be an undesirable reduction in the intensity of the hydrological cycle. With a large geoengineering intervention in the climate there are many known issues, and potentially some unexpected issues, which could arise as a result. If climate geoengineering is to be conducted, what is the optimal level of solar radiation management? Here we present the results from a set of experiments using the UK Met Office HadCM3L coupled GCM to simulate the effect of reductions in insolation on the climate of a world with four times the pre-industrial CO2 level. We consider 10 levels of SRM geoengineering from 100% application, returning global average temperature to pre-industrial levels, to 10% of this reduction in insolation. A pre-industrial control, two and four times pre-industrial CO2 experiments were also conducted. All the simulations were run for 400 years to allow the climate to reach a new equilibrium, with the last 100 years used for the climatological averages. In addition the Glimmer Ice Sheet model was used to simulate the viability of the Greenland ice sheet in each of these climates, the results of this section of the work are already published. We assess the effects of different levels of geoengineering on a high CO2 world by a number of different methods, including: temperature and precipitation changes and the stability of the Greenland Ice-Sheet. We include a measure of the change in the climate due solely to the geoengineering intervention, accounting for imperfect mitigation. We combine these variables to find a first estimate of the optimal level of solar radiation management for a high CO2 world. Global average temperature and precipitation have been shown to drop with increasing levels of SRM geoengineering, however our results show that levels of crought may remain constant or even decrease relative to the unmitigated, high CO2 world. We show that the Greenland ice sheet remains stable, in its preindustrial state, with a reduction in insolation of 60% of that required to cool the Earth to pre-industrial temperatures. We also find that the mitigation of global warming at low levels of geoengineering has few imperfections but that at higher levels of geoengineering there are profound imperfections. We combine these results to determine a subjective optimal level of geoengineering. Our results show that to minimize the level of undesired geoengineering-induced climate changes and reductions in global precipitation, whilst preserving the Greenland ice sheet, 60% of the full reduction in insolation would be required. This partial geoengineering would be cheaper to implement and would be less likely to produce unexpected side-effects.

Irvine, Peter; Ridgwell, Andy; Lunt, Dan

2010-05-01

321

State background-radiation levels: results of measurements taken during 1975-1979  

SciTech Connect

Background radiation levels across the United States have been measured by the Off-Site Pollutant Measurements Group of the Health and Safety Research Division at Oak Ridge National Laboratory (ORNL). These measurements have been conducted as part of the ORNL program of radiological surveillance at inactive uranium mills and sites formerly utilized during Manhattan Engineer District and early Atomic Energy Commission projects. The measurements included determination of /sup 226/Ra, /sup 232/Th, and /sup 238/U concentrations in surface soil samples and measurement of external gamma-ray exposure rates at 1 m above the ground surface at the location of soil sampling. This information is being utilized for comparative purposes to determine the extent of contamination present at the survey sites and surrounding off-site areas. The sampling program to date has provided background information at 356 locations in 33 states. External gamma-ray exposure rates were found to range from less than 1 to 34 ..mu..R/h, with an US average of 8.5 ..mu..R/h. The nationwide average concentrations of /sup 226/Ra, /sup 232/Th, and /sup 238/U in surface soil were determined to be 1.1, 0.98, and 1.0 pCi/g, respectively.

Myrick, T.E.; Berven, B.A.; Haywood, F.F.

1981-11-01

322

Gamma-Glutamyl Transferase Levels in Patients with Acute Ischemic Stroke  

PubMed Central

Objective. The aim of this study was to investigate the relationship between gamma-glutamyl transferase (GGT) levels, cerebrovascular risk factors, and distribution of cerebral infarct areas in patients with acute ischemic stroke (AIS). Patients and Methods. Sixty patients with AIS and 44 controls who had not cerebrovascular disease were included in the study. The patients were divided into four groups according to the location of the infarct area and evaluated as for GGT levels and the presence of diabetes mellitus (DM), hypertension (HT), and hyperlipidemia (HL). Results. The frequency of DM, HT, and HL and gender distributions were similar. The mean GGT levels were significantly higher in patients with AIS and those with relatively larger areas of infarction (P < 0.05). Increased mean GGT levels were found in the subgroup with hypertension, higher LDL-cholesterol, and triglyceride levels among cases with AIS (P < 0.05). Conclusion. Higher GGT levels in AIS patients reinforce the relationship of GGT with inflammation and oxidative stress. The observation of higher GGT levels in patients with relatively larger areas of infarction is indicative of a positive correlation between increases in infarct areas and elevated GGT levels.

Gurbuzer, Nurbanu; Ayhan Basturk, Zeliha

2014-01-01

323

Radiative Decays X(3872) -> psi(2S)+gamma and psi(4040) -> X(3872)+gamma in Effective Field Theory  

E-print Network

Heavy hadron chiral perturbation theory (HHchiPT) and XEFT are applied to the decays X(3872) -> psi(2S) + gamma and psi(4040) -> X(3872) + gamma under the assumption that the X(3872) is a molecular bound state of neutral charm mesons. In these decays the emitted photon energies are 181 MeV and 165 MeV, respectively, so HHchiPT can be used to calculate the underlying D^0 bar{D}^{0*}+ bar{D}^0 D^{0*} -> psi(2S) + gamma or psi(4040) -> (D^0 bar{D}^{0*}+ bar{D}^0 D^{0*}) + gamma transition. These amplitudes are matched onto XEFT to obtain decay rates. The decays receive contributions from both long distance and short distance processes. We study the polarization of the psi(2S) in the decay X(3872) -> psi(2S) + gamma and the angular distribution of X(3872) in the decay psi(4040) -> X(3872) + gamma and find they can be used to differentiate between different decay mechanisms as well as discriminate between 2^{-+} and 1^{++} quantum number assignments of the X(3872).

Thomas Mehen; Roxanne Springer

2011-01-26

324

Influence of gamma radiation on the elimination of the toxic effect of cystamine  

NASA Technical Reports Server (NTRS)

The time of half-elimination (T sub 50) of the toxic effects of cystamine is compared in irradiated and nonirradiated mice. The residual dose of cystamine three hours following administration of the preparation based on the change in the protector LD50 was calculated. With prophylactic use of cystamine, gamma irradiation at a dose of 850 r led to an increase in sub 50 from 1.8 (1.6 - 2.0) hours in intact mice to 2.3 (2.0 2.6) hours in irradiated animals. Three hours after preparation was used, the residual dose of cystamine was 44.2% in the irradiated mice and 24.5% of the original value in the nonirradiated animals. It is suggested that lengthening the elimination time of the toxic effect of cystamine under the influence of radiation is due to the decrease in the protector metabolism intensity under these conditions.

Vasin, M. V.; Davydov, B. I.; Antipov, V. V.; Saksonov, P. P.

1973-01-01

325

Determination of changes induced by gamma radiation in nectar of kiwi fruit ( Actinidia deliciosa)  

NASA Astrophysics Data System (ADS)

The kiwi ( Actinidia deliciosa; Actinidaceae) is an exotic fruit to Brazil, introduced from southeastern China. The kiwi fruit presents a high nutritional value, rich mainly in vitamin C and fibers, calcium, iron and phosphorus, which give it an excellent nutritional value. Its quality attributes and flavor has lead to acceptance in consuming markets, mainly among children. The objective of this work was to formulate a non-alcoholic sweetened drink based on kiwi fruits, to submit the drink to gamma radiation using increasing doses: 0 (control), 0.5, 1.0 and 2.0 kGy, and to evaluate changes in physical and chemical quality attributes. We found that no significant difference was observed between treatments relative to the control. So we could conclude that for the doses tested significant alterations in the physiochemical characteristics of the kiwi nectar were introduced.

Harder, M. N. C.; De Toledo, T. C. F.; Ferreira, A. C. P.; Arthur, V.

2009-07-01

326

Effect of gamma — radiation on vicine and convicine in broad beans ( Vicia faba L. )  

NASA Astrophysics Data System (ADS)

Broad bean ( Vicia faba L. ) is considered to be a good source of protein. The presence of vicine and convicine and their role as a causative agents of favism limited their use. The effect of gamma radiation from 60Co source was tested on solutions of a mixture of vicine and convicine. Analysis was carried out using spectrophotometric method. Reduction of 92% in vicine and convicine was observed when a dose of 10.0 kGy was used. The reduction was very much lower when powdered dry beans was irradiated. Research in progress in order to attain a higher destructive effect. Further chemical and biological studies are also required to follow up this effect.

Jaddou, H.

327

Shelf life extension of sugarcane juice using preservatives and gamma radiation processing.  

PubMed

Preserving raw sugarcane juice is a challenging problem. Sugarcane juice turns brown soon after its extraction and gets spoiled due to fermentation within hours. A combination of gamma radiation (5 kGy) with permitted preservatives and low temperature storage (10 °C) could preserve raw sugarcane juice for more than a month. The preservatives used were citric acid (0.3%), sodium benzoate (0.015%), potassium sorbate (0.025%), and sucrose (10%). The treatment helped in extending the shelf life to 15 d at ambient temperature (26 ± 2 °C) and 35 d at 10 °C. The microbial load was found to be below detectable limit within this period. The biochemicals like phenolics and flavonoids were not found to be affected by addition of these preservatives. The antioxidant activities including free radical scavenging activity, nitrite scavenging activity, and reducing power were also not significantly affected. The sensory evaluation scores showed that the juice with this combination treatment was highly acceptable. PMID:22417599

Mishra, Bibhuti B; Gautam, Satyendra; Sharma, Arun

2011-10-01

328

Disinfection of the bee hive's American foulbrood by gamma radiation from Cobalt-60  

NASA Astrophysics Data System (ADS)

Gamma radiation from Cobalt-60 was used to sterilize honeybee combs contaminated by Bacilluslarvae. The determination of the radiosensibility (D 10) was done on cultured cells in Brain Heart Infusion broth and was found to be determined at 125 Gy. The D 10 of isolated spores from contaminated combs was then determined at 0,518 kGy and the D 10 of spores irradiated in their own original environment was found at 2,05 kGy. These treated combs were then sent back in the beehives. The bees cleaned the combs thouroughly and started the storage of honey in some cells. Eggs were also layed in others. Forty five days later, there were still no sign of re-appearance of the American Foulbrood disease.

Gosselin, P.; Charbonneau, R.

329

Composition, temperature and radiation induced changes in gamma irradiated AAAMPS copolymer  

NASA Astrophysics Data System (ADS)

Effect of composition, temperature and radiation dose in gamma irradiated acrylamide-2-acrylamido-2-methyl propane sulphonic acid (AA) copolymer has been investigated by electron spin resonance (ESR) and fourier transform infrared (FTIR) techniques. ESR spectra of gamma irradiated AA copolymer have been recorded under different conditions. The observed ESR spectra are analysed by computer simulation techniques, to separate the constituent component spectra. Magnetic parameters employed to simulate the component spectra enabled the identification of corresponding free radicals. The AA copolymer with low acrylamide content composed of macroradicals of the type -CH2-CH-CH2- and methyl radicals (CH3) whereas the copolymer with high acryl amide content possess methyl radicals and radicals of the type -CH2-C(CONH2)-CH2-/CH3-C-CH3. Reasons for the variation in the formation of free radicals have been explained. The observed changes in ESR spectra of irradiated AA copolymer at higher temperatures are thought to be due to the recombination of free radicals. Formation of free radicals found to be enhanced with the increase in dose of irradiation. FTIR spectra of pure and irradiated copolymers have also confirmed the previous results.

Rao, B. S.; Indira, S.; Sridhar, V.; Punnaiah, G.; Babu, B. S.; Subbakrishna, C.

2005-06-01

330

FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)  

SciTech Connect

We describe progress in the development of new materials for portable, room-temperature, gamma-radiation detection at Pacific Northwest National Laboratory at the Hanford Site in Washington State. High Z, high resistivity, amorphous semiconductors are being designed for use as solid-state detectors at near ambient temperatures; principles of operation are analogous to single-crystal semiconducting detectors. Amorphous semiconductors have both advantages and disadvantages compared to single crystals, and this project is developing methods to mitigate technical problems and design optimized material for gamma detection. Several issues involved in the fabrication of amorphous semiconductors are described, including reaction thermodynamics and kinetics, the development of pyrolytic coating, and the synthesis of ingots. The characterization of amorphous semiconductors is described, including sectioning and polishing protocols, optical microscopy, X-ray diffraction, scanning electron microscopy, optical spectroscopy, particle-induced X-ram emission, Rutherford backscattering, and electrical testing. Then collaboration with the University of Illinois at Urbana-Champaign is discussed in the areas of Hall-effect measurements and current voltage data. Finally, we discuss the strategy for continuing the program.

Johnson, Bradley R.; Riley, Brian J.; Crum, Jarrod V.; Sundaram, S. K.; Henager, Charles H.; Zhang, Yanwen; Shutthanandan, V.

2007-01-01

331

Effect of radiation on solid paracetamol: ESR identification and dosimetric features of gamma-irradiated paracetamol  

NASA Astrophysics Data System (ADS)

In the present work, electron spin resonance (ESR) identification of gamma-irradiated paracetamol and its potential use as a normal and/or accidental dosimetric material were investigated in the dose range of 2.5-25 kGy. Both unirradiated paracetamol and mechanically ground vermidon samples exhibited a weak single resonance line at g = 2.0049 +/- 0.0006 and had Delta H-pp = 0.6 +/- 0.02 mT. Gamma irradiation produced an increase in signal intensity with a small hyperfine splitting in both paracetamol and vermidon and many weak resonance lines on both sides of a central line in the case of vermidon. Dose-response curves associated with central line of paracetamol and vermidon were found to follow polynomial and linear function, respectively. Simulation calculations based on the room temperature ESR intensity data of the paracetamol sample irradiated at 10 kGy were performed to determine the structure and spectral parameters of the radiation-induced radical species involved in the formation of the experimental ESR spectrum of paracetamol.

Polat, M.; Korkmaz, M.

2006-01-01

332

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

Code of Federal Regulations, 2010 CFR

10 Energy 1 2010-01-01 2010-01-01...external radiation levels from storage containers and source changers...34.21 Section 34.21 Energy NUCLEAR REGULATORY COMMISSION...external radiation levels from storage containers and source...

2010-01-01

333

Effect of various mouthwashes on the levels of interleukin-2 and interferon-gamma in chronic gingivitis.  

PubMed

The aim of this double blind study was to evaluate the effect of various mouthwashes: Chlorhexidine, Essential oil, Azadirachta indica (Neem) extract, and Povidone iodine on gingival tissue interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) levels in patients with chronic gingivitis. A total of 8O patients (42 boys, 38 girls; mean age 16.0 +/- 1.8 years) were included in this study. Patients were randomly assigned into four groups of 20 each: Group I--Azadirachta indica (Neem) extract, Group II--Essential oil, Group III--Povidone iodine, and Group IV--Chlorhexidine. They were instructed to use these mouthwashes for two weeks. Plaque and gingival indices scores, and IL-2 and IFN-gamma levels in the gingival tissues were measured at baseline and after two weeks of mouthwash use. Results showed the reduction of plaque and gingival indices, and IL-2 and IFN-gamma level with Chlorhexidine, Essential oil, and Povidone iodine, which were found to be statistically significant. Although Neem reduced the level of plaque and gingival indices, and IL-2 and IFN-gamma to a certain level, it was not statistically significant. Therefore, Chlorhexidine, Essential oil, and Povidone iodine mouthwashes can be used as an adjunct to oral prophylaxis in reducing pro-inflammatory cytokines, IL-2 and IFN-gamma in patients with chronic gingivitis. PMID:18389675

Sharma, Shivalal; Saimbi, C S; Koirala, Bandana; Shukla, Rakesh

2008-01-01

334

Hymenobacter swuensis sp. nov., a gamma-radiation-resistant bacteria isolated from mountain soil.  

PubMed

Gram stain-negative and non-motile bacteria, designated as DY53(T) and DY43, were isolated from mountain soil in South Korea prior exposure with 5 kGy gamma radiation. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strains belonged to the family Cytophagaceae in the class Cytophagia. 16S rRNA gene sequence similarity of strains DY53(T) and DY43 was 100 %. The highest degrees of sequence similarities of strains DY53(T) and DY43 were found with Hymenobacter perfusus A1-12(T) (98.8 %), Hymenobacter rigui WPCB131(T) (98.5 %), H. yonginensis HMD1010(T) (97.9 %), H. xinjiangensis X2-1g(T) (96.6 %), and H. gelipurpurascens Txg1(T) (96.5 %). The DNA G+C content of the novel strains DY53(T) and DY43 were 59.5 mol%. Chemotaxonomic data revealed that strains possessed major fatty acids such as C??:? iso, C??:? anteiso, C??:? ?5c, summed feature 3 (16:1 ?7c/?6c), summed feature 4 (17:1 anteiso B/iso I) and C??:? iso, and major polar lipid was phosphatidylethanolamine. The novel strains showed resistance to gamma radiation, with a D10 value (i.e., the dose required to reduce the bacterial population by tenfold) in excess of 5 kGy. Based on these data, strains DY53(T) and DY43 should be classified as representing a novel species, for which the name Hymenobacter swuensis sp. nov. is proposed, with the type strain DY53(T) (=KCTC 32018(T) = JCM 18582(T)) and DY43 (=KCTC 32010). PMID:24132326

Lee, Jae-Jin; Srinivasan, Sathiyaraj; Lim, Sangyong; Joe, Minho; Lee, Sang Hee; Kwon, Shin Ae; Kwon, Yoon Jung; Lee, Jin; Choi, Jin Ju; Lee, Hye Min; Auh, Young Kyung; Kim, Myung Kyum

2014-03-01

335

Plasma interferon-gamma-inducible protein-10 (IP-10) levels during acute hepatitis C virus infection  

PubMed Central

Systemic levels of interferon-gamma-inducible protein-10 (IP-10) are predictive of treatment-induced clearance in chronic HCV. In the present study, factors associated with plasma IP-10 levels at the time of acute HCV detection and the association between IP-10 levels and spontaneous clearance were assessed in three cohorts of acute HCV infection. Among 300 individuals, 245 (181 male, 47 HIV+) were HCV RNA+ at acute HCV detection. In adjusted analysis, factors independently associated with IP-10 levels ?150 pg/mL (median level) included HCV RNA levels >6 log IU/mL, HIV co-infection and non-Aboriginal ethnicity. Among 245 HCV RNA+ at acute HCV detection, 214 were untreated (n=137) or had persistent infection (infection duration ?26 weeks) at treatment initiation (n=77). Spontaneous clearance occurred in 14% (29 of 214). Individuals without spontaneous clearance had significantly higher mean plasma IP-10 levels at the time of acute HCV detection than those with clearance (248±32 vs. 142±22 pg/mL, P=0.008). The proportion of individuals with spontaneous clearance was 0% (0 of 22, P=0.048) and 16% (27 of 165) and in those in those with and without plasma IP-10 levels ?380 pg/mL. In adjusted analyses, favourable IL28B genotype was associated with spontaneous clearance, while higher HCV RNA level was independently associated with lower odds of spontaneous clearance. Conclusion High IP-10 levels at acute HCV detection were associated with failure to spontaneously clear HCV. Patients with acute HCV and high baseline IP-10 levels, particularly >380 pg/mL, should be considered for early therapeutic intervention, and those with low levels should defer therapy for potential spontaneous clearance. PMID:23325615

Grebely, Jason; Feld, Jordan J.; Applegate, Tanya; Matthews, Gail V.; Hellard, Margaret; Sherker, Alana; Petoumenos, Kathy; Zang, Geng; Shaw, Ineke; Yeung, Barbara; George, Jacob; Teutsch, Suzy; Kaldor, John M.; Cherepanov, Vera; Bruneau, Julie; Shoukry, Naglaa H.; Lloyd, Andrew R.; Dore, Gregory J.

2013-01-01

336

CYTOGENETIC COMPARISON OF THE RESPONSES OF MOUSE AND HUMAN PERIPHERAL BLOOD LYMPHOCYTES TO 60CO GAMMA RADIATION (JOURNAL VERSION)  

EPA Science Inventory

Experiments were conducted to compare the chromosome damaging effects of (60)Co gamma radiation on mouse and human peripheral blood lymphocytes (PBLs). Either whole blood or isolated and pelleted mononuclear leucocytes (MNLs) were irradiated with a (60)Co unit to yield exposures ...

337

The effect of oxygen impurities on radiation hardness of FZ silicon detectors for HEP after neutron, proton and gamma irradiation  

Microsoft Academic Search

The radiation hardness for fast neutrons, high energy protons and 60Co gamma rays of planar detectors processed from highly oxygenated silicon detectors obtained by using high temperature (1200°C), long time (> 200 hours) oxidation technology, are compared with standard silicon detectors. For fast neutron irradiation it is found that there is no advantage of using highly oxygenated silicon FZ detectors

B. Dezillie; Z. Li; V. Eremin; W. Chen; L. J. Zhao

2000-01-01

338

The soft gamma repeaters as very strongly magnetized neutron stars - I. Radiative mechanism for outbursts  

NASA Astrophysics Data System (ADS)

A radiative model for the soft gamma repeaters and the energetic 1979 March 5 burst is presented. We identify the sources of these bursts with neutron stars the external magnetic fields of which are much stronger than those of ordinary pulsars. Several independent arguments point to a neutron star with B_dipole~5x10^14 G as the source of the March 5 event. A very strong field can (i) spin down the star to an 8-s period in the ~10^4-yr age of the surrounding supernova remnant N49; (ii) provide enough energy for the March 5 event; (iii) undergo a large-scale interchange instability the growth time of which is comparable to the ~0.2-s width of the initial hard transient phase of the March 5 event; (iv) confine the energy that was radiated in the soft tail of that burst; (v) reduce the Compton scattering cross-section sufficiently to generate a radiative flux that is ~10^4 times the (non-magnetic) Eddington flux; (vi) decay significantly in ~10^4-10^5 yr, as is required to explain the activity of soft gamma repeater sources on this time-scale; and (vii) power the quiescent X-ray emission L_X~7x10^35 erg s^-1 observed by Einstein and ROSAT as it diffuses the stellar interior. We propose that the 1979 March 5 event was triggered by a large-scale reconnection/interchange instability of the stellar magnetic field, and the soft repeat bursts by cracking of the crust. The hard initial spike of the March 5 event is identified with an expanding pair fireball, and the soft tail of that burst, together with the short, soft repeat bursts, with a pair plasma trapped in the stellar magnetosphere. We construct a detailed radiative model that describes the cooling of such a plasma. The opacity is dominated by the electron-baryon contaminant in a cold surface layer, and the plasma releases energy as the edge of the pair-dominated region propagates inward, in a cooling wave. The rate at which the plasma volume contracts is limited either by the rate of advection of heat toward the stellar surface (where the field is strongest and the scattering opacity weakest), or by ablation of ions and electrons from the stellar surface. The effective temperature of the surface radiation depends only on the surface magnetic field strength in the regime where the radiative flux is limited by ablation from the neutron star surface (which is the regime of interest in the March 5 event), and otherwise is weakly dependent on the plasma energy density. We argue that the deposition of equivalent energy in a much weaker magnetic field (characteristic of ordinary pulsars) necessarily generates a very high scattering depth which chokes off the radiative flow on the observed ~0.1-s time-scale of soft gamma repeater bursts. Indeed, we suggest that the same basic magnetospheric emission mechanism operates at lower field strengths (B~10^12 G) in Type II X-ray bursts, which have much lower luminosities than soft gamma repeater bursts. Important magnetic radiative effects include the suppression of Compton scattering in the extraordinary polarization mode, and stimulated photon splitting. We derive the Boltzmann equations for the photon occupation number which describe simulated photon splitting, as well as photon merging. We show that the net splitting rate vanishes in thermal equilibrium. Radiative diffusion occurs primarily in the E-mode, although rapid scattering of the O-mode ensures convergence of the photon distribution function to a Bose-Einstein form. This allows us to write down diffusion equations for the photon energy flux and number flux as linear superpositions of gradients in the temperature and chemical potential. The transition from a Planck to a Bose-Einstein spectrum occurs at T~10 keV. Photon splitting at higher temperatures can impede free-streaming of photons across the magnetic field lines, but splitting of high-energy photons is impeded by the inverse process of photon merging. We demonstrate that only a small fraction of the pair bubble energy can be conducted into the crust during the lifetime of the burst. We discuss the radiative ablation of m

Thompson, Christopher; Duncan, Robert C.

1995-07-01

339

SCATTERED GAMMA RADIATION MEASUREMENTS FROM A Co⁶° CONTAMINATED FIELD  

Microsoft Academic Search

A 90 deg sector of a circle of 604-foot radius was contamirated with ; cobalt-60 point sources to an approximate level of 1.72 millicuries per square ; foot, as a means of simulating an area approaching an infinite contaminated field. ; Radiation measurements were made in an open hole with a PDR-27A radiac instrument ; and Dupont 553 film to

C. L. Schlemm; A. E. Jr. Anthony; Z. G. Burson

1959-01-01

340

Determination of environmental radiation flux and organ doses using in-situ gamma spectroscopy  

NASA Astrophysics Data System (ADS)

Contamination of buildings represent a unique problem during Decontamination and Decommissioning (D&D) of nuclear facilities. It is necessary to determine the long-lived radionuclides and their respective specific activities in building materials before the right D&D decision can be made. At the same time, radiation risk of workers or potential occupants in the facility must be assessed as part of the D&D process. The goal of this project was to develop a methodology of obtaining gamma radiation flux and organ doses from in-situ gamma spectroscopy. Algorithms were developed to simulate the response functions of the HPGe detector and to convert the spectra into photon fluences. A Monte Carlo code, MCNP4C, was used to simulate HPGe detector response and to develop the conversion algorithm. The simulated spectra obtained for an HPGe detector were converted to flux using the algorithm for various different geometries. The response functions of the detector are presented in this document for the gamma energies from 60 keV to 2.2 MeV. Published fluence-to-dose conversion coefficients were used to calculate organ doses and effective dose equivalent. We then tested the theory at a 100-MeV linear electron accelerator at Rensselaer Polytechnic Institute (RPI). Samples of the activated concrete walls and floor in the target room of the Linac facility as well as some steel samples were taken to quantify the specific activities of the structures. The results show that the most important long-lived radionuclides include 22 Na, 46Sc, 54 Mn, 57Co, 60 Co, 65Zn, 152 Eu and 154Eu, depending on the location and composition of the material. The specific activities at the Linac facility range from 1.15E-01 to 765.31 muCi/Kg. The annual effective dose equivalent was assessed to be 2.44 mSv y-1 (0.244 rem y-1 ), which is about 5% of the Annual EDE limits to workers.

Al-Ghamdi, Abdulrahman S.

341

A comparison of radiation damage in liner ICs from cobalt-60 gamma rays and 2.2-MeV electrons  

NASA Technical Reports Server (NTRS)

The total ionizing dose response of fourteen IC types from eight manufacturers was measured using Co-60 gamma rays and 2.2-MeV electrons for exposure levels of 100 to 20,000 Gy(Si). Key parameter measurements were made and compared for each device type. The data show that a Co-60 source is not a suitable simulation source for some systems because of the generally more damaging nature of electrons as well as the unpredictable nature of the individual device response to the two types of radiations used here.

Gauthier, M. K.; Nichols, D. K.

1983-01-01

342

Measurement of Inclusive Radiative B -Meson Decay B -> X_s gamma  

SciTech Connect

Radiative decays of the B meson, B {yields} X{sub s}{gamma}, proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B {yields} X{sub s}{gamma} decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as e{sup +}e{sup -} annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 {+-} 0.16) GeV/c{sup 2}; {mu}{sub {pi}}{sup 2} = (0.65 {+-} 0.29) GeV{sup 2}. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter |V{sub ub}|. Based on these parameters and heavy quark expansion, the full branching fraction is obtained as: {Beta}(B {yields} X{sub s}{gamma}){sup E{sub {gamma}}>1.6 GeV} = (4.05 {+-} 0.32(stat) {+-} 0.38(syst) {+-} 0.29(model)) x 10{sup -4}. This result is in good agreement with previous measurements, the statistical and systematic errors are comparable. It is also in good agreement with the theoretical Standard Model predictions, and thus within the present errors there is no indication of any interactions not accounted for in the Standard Model. This finding implies strong constraints on physics beyond the Standard Model.

Ozcan, V.E.; /SLAC /Stanford U., Appl. Phys. Dept.

2006-01-06

343

GRABGAM: A Gamma Analysis Code for Ultra-Low-Level HPGe SPECTRA  

SciTech Connect

The GRABGAM code has been developed for analysis of ultra-low-level HPGe gamma spectra. The code employs three different size filters for the peak search, where the largest filter provides best sensitivity for identifying low-level peaks and the smallest filter has the best resolution for distinguishing peaks within a multiplet. GRABGAM basically generates an integral probability F-function for each singlet or multiplet peak analysis, bypassing the usual peak fitting analysis for a differential f-function probability model. Because F is defined by the peak data, statistical limitations for peak fitting are avoided; however, the F-function does provide generic values for peak centroid, full width at half maximum, and tail that are consistent with a Gaussian formalism. GRABGAM has successfully analyzed over 10,000 customer samples, and it interfaces with a variety of supplementary codes for deriving detector efficiencies, backgrounds, and quality checks.

Winn, W.G.

1999-07-28

344

Influence of shielding certain parts of the body on the course of radiation sickness in dogs with total gamma irradiation  

NASA Technical Reports Server (NTRS)

In an experiment on dogs which were subjected to total gamma irradiation at lethal doses, the influence of shielding the head and the anterior part of the stomach on the clinical course and outcome of radiation sickness was studied. The experiment results supported the basic data obtained in experiments on small laboratory animals and showed the high effectiveness of shielding a part of the body in dogs. In protecting various masses of tissue with shieldings that provided equal attenuation of the radiation and with an equal dose of radiation, shielding of parts of the anterior portion of the stomach was much more effective than shielding the head.

Razgovorov, B. L.; Konnova, N. I.

1973-01-01

345

Influence of pharmacochemical substances on the reactivity of the organism to the combined action of gamma radiation and transverse overloads  

NASA Technical Reports Server (NTRS)

Under the combined exposure of mice to gamma radiation from Co-60 in doses of 350 and 700 r and transverse overloads (10 units, 30 minutes), the effectiveness of cystamine and AET in amounts of 75 mg/kg each was studied. The effect of overloads 24 hours prior to irradiation reduces the radiation damage of hemopoietic organs. In mice that were subjected to the action of overloads 24 hours after irradiation, there was an insignificant increase in the radiation damage to the spleen and marrow and an increase in the destructive changes in the peripheral nervous system. Cystamine combined with AET has an antiradiation protective effects.

Gaydamakin, N. A.; Kulkin, S. G.; Davydov, B. I.; Shashkov, V. S.

1973-01-01

346

High doses of gamma radiation suppress allergic effect induced by food lectin  

NASA Astrophysics Data System (ADS)

One of the most promising areas for the development of functional foods lies in the development of effective methods to reduce or eliminate food allergenicity, but few reports have summarized information concerning the progress made with food irradiation. In this study, we investigated the relationship between allergenicity and molecular structure of a food allergen after gamma irradiation and evaluate the profile of the allergic response to irradiated allergens. Cramoll, a lectin isolated from a bean and used as a food allergen, was irradiated and the possible structural changes were accompanied by spectrofluorimetry, circular dichroism and microcalorimetry. Subsequently, sensitized animals subjected to intragastric administration of non-irradiated and irradiated Cramoll were treated for 7 days. Then, body weight, leukocytes, cytokine profiles and histological parameters were also determined. Cramoll showed complete inhibition of intrinsic activity after high radiation doses. Changes in fluorescence and CD spectra with a simultaneous collapse of the tertiary structure followed by a pronounced decrease of native secondary structure were observed after irradiation. After oral challenge, sensitized mice demonstrate an association between Cramoll intake, body weight loss, eosinophilia, lymphocytic infiltrate in the gut and Eotaxin secretion. Irradiation significantly reduces, according to the dose, the effects observed by non-irradiated food allergens. We confirm that high-dose radiation may render protein food allergens innocuous by irreversibly compromising their molecular structure.

Vaz, Antônio F. M.; Souza, Marthyna P.; Vieira, Leucio D.; Aguiar, Jaciana S.; Silva, Teresinha G.; Medeiros, Paloma L.; Melo, Ana M. M. A.; Silva-Lucca, Rosemeire A.; Santana, Lucimeire A.; Oliva, Maria L. V.; Perez, Katia R.; Cuccovia, Iolanda M.; Coelho, Luana C. B. B.; Correia, Maria T. S.

2013-04-01

347

Grad-Level Radiation Damage of SIO2 Detectors  

SciTech Connect

Radiation effects and levels to detectors. SiO{sub 2} quartz fibers of the LHC ATLAS Zero-degree Calorimeter (ZDC) anticipated to experience integrated doses of a few Grad at their closest position were exposed to 200 MeV protons and neutrons at the Brookhaven National Laboratory (BNL) Linac. Specifically, 1 mm- and 2mm-diameter quartz (GE 124) rods were exposed to direct 200 MeV protons during the first phase of exposure leading to peak integrated dose of {approx}28 Grad. Exposure to a primarily neutron flux of 1mm-diameter SiO{sub 2} fibers was also achieved with a special neutron source arrangement. In a post-irradiation analysis the quartz fiber transmittance was evaluated as a function of the absorbed dose. Dramatic degradation of the transmittance property was observed with increased radiation damage. In addition, detailed evaluation of the fibers under the microscope revealed interesting micro-structural damage features and irradiation-induced defects.

Simos, N.; Atoian, G.; Ludewig, H; White, S; O'Conor, J; Mokhov, N.V.

2009-05-04

348

The effects of physicochemical properties on gamma emitting natural radionuclide levels in the soil profile of Istanbul  

Microsoft Academic Search

The inventory of gamma-emitting radionuclides was determined in soil samples collected at six depth levels, from 15 locations\\u000a in Istanbul metropolis. The activity concentrations of 232Th, 238U, 40K were measured by means of gamma spectrometry. The average activity concentrations of 232Th, 238U, 40K in the 30-cm depth soil were found as 32.1, 27.4, 393.1 Bq kg???1, respectively. The mean value of

Murat Belivermis; Yavuz Çotuk; Sayhan Topcuo?lu

2010-01-01

349

Low Level Laser Therapy: laser radiation absorption in biological tissues  

NASA Astrophysics Data System (ADS)

In this paper we report the results of an experimental study in which we have measured the transmitted laser radiation through dead biological tissues of various animals (chicken, adult and young bovine, pig) in order to evaluate the maximum thickness through which the power density could still produce a reparative cellular effect. In our experiments we have utilized a pulsed laser IRL1 ISO model (based on an infrared diode GaAs, ?=904 nm) produced by BIOMEDICA s.r.l. commonly used in Low Level Laser Therapy. Some of the laser characteristics have been accurately studied and reported in this paper. The transmission results suggest that even with tissue thicknesses of several centimeters the power density is still sufficient to produce a cell reparative effect.

Di Giacomo, Paola; Orlando, Stefano; Dell'Ariccia, Marco; Brandimarte, Bruno

2013-07-01

350

IFN-{gamma}+ CD8+ T Lymphocytes: Possible Link Between Immune and Radiation Responses in Tumor-Relevant Hypoxia  

SciTech Connect

Activated T lymphocytes are known to kill tumor cells by triggering cytolytic mechanisms; however, their ability to enhance radiation responses remains unclear. This study examined the radiosensitizing potential of mouse CD8+ T cells, obtained by T-cell-tailored expansion and immunomagnetic purification. Activated CD8+ T cells displayed an interferon (IFN)-{gamma}+ phenotype and enhanced by 1.8-fold the radiosensitivity of EMT-6 tumor cells in 1% oxygen, which modeled tumor-relevant hypoxia. Radiosensitization was counteracted by neutralizing IFN-{gamma} or by blocking the inducible isoform of nitric oxide synthase, thus delineating the immune-tumor cell interaction through the IFN-{gamma} secretion pathway. Reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and fluorescence-activated cell sorter data in agreement detected downregulation of the IFN-{gamma} gene by hypoxia, which caused IFN-{gamma} deficiency next to radioresistance. Therefore, immune and radiation responses are likely to be allied in the hypoxic tumor microenvironment, and CD8+ T cells may bridge immunostimulatory and radiosensitizing strategies.

De Ridder, Mark [Radiotherapie, Oncologisch Centrum, UZ Brussel, Brussels (Belgium); Cancer Research Unit, Vrije Universiteit Brussel, Brussels (Belgium)], E-mail: mark.deridder@uzbrussel.be; Jiang Heng; Esch, Gretel van; Law, Kalun; Monsaert, Christinne [Cancer Research Unit, Vrije Universiteit Brussel, Brussels (Belgium); Berge, Dirk L. van den; Verellen, Dirk; Verovski, Valeri N. [Radiotherapie, Oncologisch Centrum, UZ Brussel, Brussels (Belgium); Storme, Guy A. [Radiotherapie, Oncologisch Centrum, UZ Brussel, Brussels (Belgium); Cancer Research Unit, Vrije Universiteit Brussel, Brussels (Belgium)

2008-07-01

351

Inhaled /sup 239/PuO/sub 2/ and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs  

SciTech Connect

Rats and beagle dogs were given doses of /sup 60/Co gamma radiation and/or body burdens of /sup 239/PuO/sub 2/ within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell concentrations and by long-term loss of body weight and diminished pulmonary function in animals of both species that survived the acute gamma radiation syndrome. Inhaled plutonium caused a loss of body weight and diminished pulmonary function in both species, but its only effect on blood cell concentrations was lymphocytopenia in dogs. Combined gamma irradiation and plutonium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Plutonium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the long-term effect of plutonium lung burdens in both species. Rats were less sensitive to both kinds of radiation, whether administered alone or in combination. 71 refs., 105 figs., 48 tabs.

Filipy, R.E.; Decker, J.R.; Lai, Y.L.; Lauhala, K.E.; Buschbom, R.L.; Hiastala, M.P.; McGee, D.R.; Park, J.F.; Kuffel, E.G.; Ragan, H.A.; Cannon, W.C.; Yaniv, S.S.; Scott, B.R.

1988-08-01

352

Exposure to indoor radon and natural gamma radiation in some workplaces at Algiers, Algeria.  

PubMed

Radon activity concentrations have been measured in 34 workplaces throughout Algiers nuclear research centre, in Algeria, during some periods between March 2007 and June 2013 using Electret ion chambers, nuclear tracks detectors and an AlphaGuard system. The indoor radon levels range from 2 to 628 Bq m(-3) with an average indoor concentration equals to 92 Bq m(-3), whereas the estimated outdoor radon concentrations range from 2 to 14 Bq m(-3) with an average value of 6 Bq m(-3). This study also focused on parameters affecting radon concentration levels such as ?oor number, ventilation and atmospheric parameters. Furthermore, the mean gamma rates have been measured in the different investigated locations and have been found to be varying between 33 and 3300 nSv h(-1). The annual effective dose for workers calculated using the appropriate equilibrium and occupancy factors is lower than the value recommended by International Commission on Radiological Protection in its Publication 103. PMID:24711531

Aït Ziane, M; Lounis-Mokrani, Z; Allab, M

2014-07-01

353

Spectroscopic investigation of gamma radiation-induced coloration in silicate glass for nuclear applications  

NASA Astrophysics Data System (ADS)

Silicate glass irradiated by ?-rays was investigated in this study using spectroscopic analyses which included ultraviolet-visible (UV-Vis) absorption, electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR). The phenomenon of coloration on ?-ray-irradiated silicate glass was analyzed and the effect of annealing on the silicate coloration was also investigated. The results revealed that the coloration originates from the creation of hole-centers (HC) caused by radiation. The shade of the coloration highly correlates to the amount of these HC-related defects but can be reversed by thermal annealing. The variation in coloration is an effective predictive factor in understanding radiation damage on silicate glass. Therefore, this study is relevant in the development of radiation detectors using silicate material as well as in the permanent disposal of high-level nuclear waste in glass form.

Tsai, Hsu-Sheng; Chao, Der-Sheng; Wu, Ya-Hsuan; He, Yu-Ting; Chueh, Yu-Lun; Liang, Jenq-Horng

2014-10-01

354

Studies on High Energy Radiation Mechanisms and Gamma-Ray Burst Prompt Emissions  

NASA Astrophysics Data System (ADS)

Gamma-Ray Bursts (GRBs) are the most violent high-energy explosion in the universe. They are randomly happened, pulse-like phenomena with short durations. Since its discovery in 1960's by Vela satellite, GRBs have become a hot topic for astrophysical research. In 1997 the BeppoSAX satellite discovered afterglows of GRBs, and then helped to measure GRB redshifts. Thus it was found that GRBs are the events occurred at cosmological distances. Now it is widely accepted that the long bursts with durations longer than 2 s are from the collapsing massive stars, while the short bursts with durations less than 2 s are results of the merging compact binaries. By studying GRBs, the physical processes in ultrarelativistic and very high energy conditions can be investigated, and the researches on other fields, including constraining the cosmological models, can also get helped. The goal of this thesis is to present some discussions on possible radiation mechanisms and prompt light curves of GRBs. Since radiation mechanisms and prompt emissions are related to GRB central engines directly, studying these topics can help us to get a better understanding of some properties of the central engine. In Chapter 1, we review the discovery and observations of GRBs, presenting major achievements from major GRB-monitoring satellites including Compton Gamma-ray Observatory, BeppoSAX satellite, Swift satellite, as well as the latest Fermi Gamma-ray Space Telescope. The multi-wavelength properties of prompt emission as well as afterglows of GRBs are also summarized in Chapter 1. In Chapter 2 the current GRB standard model is presented. According to standard model, a fireball is ejected by the central engine. The internal shock is produced by collisions between various shells with different velocities inside the fireball. The directional kinetic energy of the fireball is then converted to internal energy, and finally the non-thermal radiation (the prompt emission) is produced by internal shocks. And the interaction between the fireball and the outer medium gives rise to external forward and reverse shocks, producing the observed afterglow. In the framework of standard model, we introduce the properties of the fireball, the evolution of shocks, some possible radiation mechanisms, as well as some post-standard effects. Also we present a brief introduction of central engines. And since the internal shock model for prompt emission has some problems hard to be solved, we also introduce some possible alternatives, including the electromagnetic model, the turbulent model, as well as the Internal-Collision-induced Magnetic Reconnection and Turbulence (ICMART) model. In Chapter 3, we present the spectrum of synchro-curvature self-Compton (SCSC) radiation of relativistic electrons with a power-law distribution of Lorentz factors. Synchro-curvature radiation from relativistic electrons moving around curved magnetic field lines and its self-Compton radiation are possible radiation mechanisms in the GRB enviroment. We find that the resulting SCSC spectrum is significantly different from that of either synchrotron self-Compton or curvature self-Compton radiation if both the curvature radius of the magnetic field and the cyclotron radius of the electrons are within some proper ranges. The effects of electrons' cooling and drifting, the low-energy self absorption in seed spectra, and the Klein-Nishina cutoff are also discussed, in order to get an accurate picture. We take GRBs as our example environment for discussions. The results would be considered as a universal approach of the self-Compton emission of relativistic electrons moving in curved magnetic fields, and thus could be applied to many astrophysical phenomena, including active galactic nuclei (AGNs), pulsars, as well as GRBs. In Chapter 4, we simulate the prompt emission light curves of GRBs within the framework of the ICMART model. This model is applied to GRBs with a moderately-high magnetization parameter ? in the emission region. We show that this model can produce highly variable light curves with bo

Zhang, B.

2014-07-01

355

RBE (relative biological effectiveness) of tritium beta radiation to gamma radiation and x-rays analyzed by both molecular and genetic methods  

SciTech Connect

The relative biological effectiveness (RBE) of tritium beta radiation to /sup 60/Co gamma radiation was determined using sex-linked recessive lethals (SLRL) induced in Drosophila melanogaster spermatozoa as the biological effect. The SLRL test, a measure of mutations induced in germ cells transmitted through successive generations, yields a linear dose-response curve in the range used in these experiments. From these ratios of the slopes of the /sup 3/H beta and the /sup 60/ Co gamma radiation linear dose response curves, an RBE of 2.7 is observed. When sources of error are considered, this observation suggests that the tritium beta particle is 2.7 /plus minus/ 0.3 times more effective per unit of energy absorbed in inducing gene mutations transmitted to successive generation than /sup 60/Co gamma radiation. Ion tracks with a high density of ions (high LET) are more efficient than tracks with a low ion density (low LET) in inducing transmissible mutations, suggesting interaction among products of ionization. Molecular analysis of x-ray induced mutations shows that most mutations are deletions ranging from a few base pairs as determined from sequence data to multi locus deletions as determined from complementation tests and Southern blots. 14 refs., 1 fig.

Lee, W.R.

1988-01-01

356

An analysis of a spreader bar crane mounted gamma-ray radiation detection system  

NASA Astrophysics Data System (ADS)

Over 95% of imports entering the United States from outside North America arrive via cargo containers by sea at 329 ports of entry. The current layered approach for the detection only scans 5% of cargo bound for the United States. This is inadequate to protect our country. This research involved the building of a gamma-ray radiation detection system used for cargo scanning. The system was mounted on a spreader bar crane (SBC) at the Port of Tacoma (PoT) and the applicability and capabilities of the system were analyzed. The detection system provided continuous count rate and spectroscopic data among three detectors while operating in an extreme environment. In a separate set of experiments, 60Co and 137Cs sources were positioned inside a cargo container and data were recorded for several count times. The Monte Carlo N-Particle (MCNP) code was used to simulate a radioactive source inside an empty cargo container and the results were compared to experimentally recorded data. The detection system demonstrated the ability to detect 60Co, 137Cs, 192 Ir, highly-enriched uranium (HEU), and weapons-grade plutonium (WGPu) with minimum detectable activities (MDA) of 5.9 +/- 0.4 microcuries (muCi), 19.3 +/- 1.1 muCi, 11.7 +/- 0.6 muCi, 3.5 +/- 0.3 kilograms (kg), and 30.6 +/- 1.3 grams (g), respectively. This system proved strong gamma-ray detection capabilities, but was limited in the detection of fissile materials Additional details of this system are presented and advantages of this approach to cargo scanning over current approaches are discussed.

Grypp, Matthew David

357

10 CFR 840.4 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

...of radioactive material or substantial radiation levels offsite. 840.4 Section...of radioactive material or substantial radiation levels offsite. DOE will determine...there have been substantial levels of radiation offsite, when as a result of an...

2014-01-01

358

10 CFR 840.4 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2011 CFR

...of radioactive material or substantial radiation levels offsite. 840.4 Section...of radioactive material or substantial radiation levels offsite. DOE will determine...there have been substantial levels of radiation offsite, when as a result of an...

2011-01-01

359

10 CFR 840.4 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2012 CFR

...of radioactive material or substantial radiation levels offsite. 840.4 Section...of radioactive material or substantial radiation levels offsite. DOE will determine...there have been substantial levels of radiation offsite, when as a result of an...

2012-01-01

360

10 CFR 140.84 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2013 CFR

...of radioactive material or substantial radiation levels offsite. 140.84 Section...of radioactive material or substantial radiation levels offsite. The Commission...there have been substantial levels of radiation offsite, when, as a result of...

2013-01-01

361

10 CFR 140.84 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2011 CFR

...of radioactive material or substantial radiation levels offsite. 140.84 Section...of radioactive material or substantial radiation levels offsite. The Commission...there have been substantial levels of radiation offsite, when, as a result of...

2011-01-01

362

10 CFR 140.84 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2012 CFR

...of radioactive material or substantial radiation levels offsite. 140.84 Section...of radioactive material or substantial radiation levels offsite. The Commission...there have been substantial levels of radiation offsite, when, as a result of...

2012-01-01

363

10 CFR 840.4 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2013 CFR

...of radioactive material or substantial radiation levels offsite. 840.4 Section...of radioactive material or substantial radiation levels offsite. DOE will determine...there have been substantial levels of radiation offsite, when as a result of an...

2013-01-01

364

10 CFR 840.4 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2010 CFR

...of radioactive material or substantial radiation levels offsite. 840.4 Section...of radioactive material or substantial radiation levels offsite. DOE will determine...there have been substantial levels of radiation offsite, when as a result of an...

2010-01-01

365

10 CFR 140.84 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

...of radioactive material or substantial radiation levels offsite. 140.84 Section...of radioactive material or substantial radiation levels offsite. The Commission...there have been substantial levels of radiation offsite, when, as a result of...

2014-01-01

366

10 CFR 140.84 - Criterion I-Substantial discharge of radioactive material or substantial radiation levels offsite.  

Code of Federal Regulations, 2010 CFR

...of radioactive material or substantial radiation levels offsite. 140.84 Section...of radioactive material or substantial radiation levels offsite. The Commission...there have been substantial levels of radiation offsite, when, as a result of...

2010-01-01

367

Ultrasound Thermometry for Therapy-level Radiation Dosimetry  

Microsoft Academic Search

Radiation oncology is the process of administering a specified dose of radiation to a patient currently receiving treatment for a form of cancer. In this process, it is vital to know the delivered dose for a given radiation beam to correctly treat a patient. The primary reference standard for absorbed dose is established using water calorimetry. The absorbed dose, typically

Courtney Taylor

2010-01-01

368

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Limits on external radiation levels from storage containers and source...LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC...Equipment § 34.21 Limits on external radiation levels from storage containers and...

2012-01-01

369

28 CFR 79.44 - Proof of working level month exposure to radiation.  

Code of Federal Regulations, 2012 CFR

...Proof of working level month exposure to radiation. 79.44 Section 79.44 Judicial...JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility...Proof of working level month exposure to radiation. (a) If one or more of the...

2012-07-01

370

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Limits on external radiation levels from storage containers and source...LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC...Equipment § 34.21 Limits on external radiation levels from storage containers and...

2013-01-01

371

28 CFR 79.44 - Proof of working level month exposure to radiation.  

Code of Federal Regulations, 2011 CFR

...Proof of working level month exposure to radiation. 79.44 Section 79.44 Judicial...JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility...Proof of working level month exposure to radiation. (a) If one or more of the...

2011-07-01

372

28 CFR 79.44 - Proof of working level month exposure to radiation.  

Code of Federal Regulations, 2013 CFR

...Proof of working level month exposure to radiation. 79.44 Section 79.44 Judicial...JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility...Proof of working level month exposure to radiation. (a) If one or more of the...

2013-07-01

373

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

...2014-01-01 false Limits on external radiation levels from storage containers and source...LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC...Equipment § 34.21 Limits on external radiation levels from storage containers and...

2014-01-01

374

10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Limits on external radiation levels from storage containers and source...LICENSES FOR INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC...Equipment § 34.21 Limits on external radiation levels from storage containers and...

2011-01-01

375

28 CFR 79.44 - Proof of working level month exposure to radiation.  

Code of Federal Regulations, 2010 CFR

...Proof of working level month exposure to radiation. 79.44 Section 79.44 Judicial...JUSTICE (CONTINUED) CLAIMS UNDER THE RADIATION EXPOSURE COMPENSATION ACT Eligibility...Proof of working level month exposure to radiation. (a) If one or more of the...

2010-07-01

376

Exposure Dose Reconstruction from EPR Spectra of Tooth Enamel Exposed to the Combined Effect of X-rays and Gamma Radiation  

NASA Astrophysics Data System (ADS)

We have used EPR dosimetry on tooth enamel to show that the combined effect of x-rays with effective energy 34 keV and gamma radiation with average energy 1250 keV leads to a significant increase in the reconstructed absorbed dose compared with the applied dose from a gamma source or from an x-ray source or from both sources of electromagnetic radiation. In simulation experiments, we develop an approach to estimating the contribution of diagnostic x-rays to the exposure dose formed in the tooth enamel by the combined effect of x-rays and gamma radiation.

Kirillov, V. A.; Kuchuro, J. I.

2014-09-01

377

The Regularities of Mutagenic Action of gamma-Radiation on Vegetative Bacillus subtilis Cells with Different Repair Genotype  

E-print Network

The regularities of induction of his^-\\to his^+ mutations in vegetative Bacillus subtilis cells with different repair capacity after gamma-irradiation have been studied. The wild type cells, polA1, recE4, recA, recP, add5, recH were used in experiments. It was shown that radiation-induced mutagenesis is determined by a repair genotype of cells. The blocking of different reparation genes is reflected on mutagenesis ratio by the various ways. A frequency of induction mutations in polA strain is higher than in wild type cells and it is characterized by the linearly-quadratic dose curve. The different rec^- strains that belong to various epistatic groups reveal an unequal mutation induction. The add5 and recP strains are characterized by the high-level induction mutations in contrast with the wild type cells. The mutagenesis in recE and recH strains, on the contrary, sharply reduces. The different influence of rec genes inhering to various epistatic groups on mutagenesis in Bacillus subtilis cells probably reflec...

Boreyko, A V; Krasavin, E A

2000-01-01

378

Search for dimuon decays of a light scalar boson in radiative transitions Upsilon-->gammaA0.  

PubMed

We search for evidence of a light scalar boson in the radiative decays of the Upsilon(2S) and Upsilon(3S) resonances: Upsilon(2S,3S)-->gammaA0, A0-->mu+mu-. Such a particle appears in extensions of the standard model, where a light CP-odd Higgs boson naturally couples strongly to b quarks. We find no evidence for such processes in the mass range 0.212 < or = mA0 < or = 9.3 GeV in the samples of 99 x 10(6) Upsilon(2S) and 122 x 10(6) Upsilon(3S) decays collected by the BABAR detector at the SLAC PEP-II B factory and set stringent upper limits on the effective coupling of the b quark to the A0. We also limit the dimuon branching fraction of the etab meson: B(etab-->mu+mu-)<0.9% at 90% confidence level. PMID:19792717

Aubert, B; Karyotakis, Y; Lees, J P; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V; Garra Tico, J; Grauges, E; Martinelli, M; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Battaglia, M; Brown, D N; Kerth, L T; Kolomensky, Yu G; Lynch, G; Osipenkov, I L; Petigura, E; Tackmann, K; Tanabe, T; Hawkes, C M; Soni, N; Watson, A T; Koch, H; Schroeder, T; Asgeirsson, D J; Fulsom, B G; Hearty, C; Mattison, T S; McKenna, J A; Barrett, M; Khan, A; Randle-Conde, A; Blinov, V E; Bukin, A D; Buzykaev, A R; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Atmacan, H; Gary, J W; Liu, F; Long, O; Vitug, G M; Yasin, Z; Sharma, V; Campagnari, C; Hong, T M; Kovalskyi, D; Mazur, M A; Richman, J D; Beck, T W; Eisner, A M; Heusch, C A; Kroseberg, J; Lockman, W S; Martinez, A J; Schalk, T; Schumm, B A; Seiden, A; Wang, L; Winstrom, L O; Cheng, C H; Doll, D A; Echenard, B; Fang, F; Hitlin, D G; Narsky, I; Ongmongkolku, P; Piatenko, T; Porter, F C; Andreassen, R; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Bloom, P C; Ford, W T; Gaz, A; Hirschauer, J F; Nagel, M; Nauenberg, U; Smith, J G; Wagner, S R; Ayad, R; Toki, W H; Wilson, R J; Feltresi, E; Hauke, A; Jasper, H; Karbach, T M; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Kobel, M J; Nogowski, R; Schubert, K R; Schwierz, R; Volk, A; Bernard, D; Latour, E; Verderi, M; Clark, P J; Playfer, S; Watson, J E; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Fioravanti, E; Franchini, P; Luppi, E; Munerato, M; Negrini, M; Petrella, A; Piemontese, L; Santoro, V; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Contri, R; Guido, E; Lo Vetere, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Tosi, S; Chaisanguanthum, K S; Morii, M; Adametz, A; Marks, J; Schenk, S; Uwer, U; Bernlochner, F U; Klose, V; Lacker, H M; Bard, D J; Dauncey, P D; Tibbetts, M; Behera, P K; Charles, M J; Mallik, U; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y Y; Gritsan, A V; Guo, Z J; Arnaud, N; Béquilleux, J; D'Orazio, A; Davier, M; Derkach, D; Firmino da Costa, J; Grosdidier, G; Le Diberder, F; Lepeltier, V; Lutz, A M; Malaescu, B; Pruvot, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Burke, J P; Chavez, C A; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Touramanis, C; Bevan, A J; Clarke, C K; Di Lodovico, F; Sacco, R; Sigamani, M; Cowan, G; Paramesvaran, S; Wren, A C; Brown, D N; Davis, C L; Denig, A G; Fritsch, M; Gradl, W; Hafner, A; Alwyn, K E; Bailey, D; Barlow, R J; Jackson, G; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Dallapiccola, C; Salvati, E; Cowan, R; Dujmic, D; Fisher, P H; Henderson, S W; Sciolla, G; Spitznagel, M; Yamamoto, R K; Zhao, M; Patel, P M; Robertson, S H; Schram, M; Biassoni, P; Lazzaro, A; Lombardo, V; Palombo, F; Stracka, S; Bauer, J M; Cremaldi, L; Godang, R; Kroeger, R; Sonnek, P; Summers, D J; Zhao, H W; Simard, M; Taras, P; Nicholson, H; De Nardo, G; Lista, L; Monorchio, D; Onorato, G; Sciacca, C; Raven, G; Snoek, H L; Jessop, C P; Knoepfel, K J; LoSecco, J M; Wang, W F; Corwin, L A; Honscheid, K; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Sekula, S J; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Castelli, G; Gagliardi, N; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; del Amo Sanchez, P; Ben-Haim, E; Bonneaud, G R; Briand, H; Chauveau, J; Hamon, O; Leruste, Ph; Marchiori, G; Ocariz, J; Perez, A; Prendki, J; Sitt, S; Gladney, L; Biasini, M; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Calderini, G; Carpinelli, M; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Lopes Pegna, D; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Anulli, F; Baracchini, E; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Renga, F; Voena, C; Ebert, M; Hartmann, T; Schröder, H; Waldi, R; Adye, T; Franek, B; Olaiya, E O; Wilson, F F; Emery, S; Esteve, L; Hamel de Monchenault, G; Kozanecki, W; Vasseur, G; Yèche, Ch; Zito, M; Allen, M T; Aston, D; Bartoldus, R; Benitez, J F; Cenci, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Franco Sevilla, M; Gabareen, A M; Graham, M T; Grenier, P; Hast, C; Innes, W R; Kaminski, J; Kelsey, M H; Kim, H; Kim, P

2009-08-21

379

Proton and Gamma Radiation Effects in Undoped, Single-doped and co-doped YLiF4 and LuLiF4  

NASA Technical Reports Server (NTRS)

Proton and gamma radiation effects in various YLiF4 and LuLiF4 crystals have been investigated. The radiation induced color centers compared with six different kinds of crystal samples in ranges up to 200 krads and 200 MeV. The radiation induced absorption coefficients are strongly dependent on polarization and concentration of rare-earth ions.

Lee, Hyung; Bai, Yingxin; Yu, Kirong; Singh, U.

2009-01-01

380

Mutant quantity and quality in mammalian cells (A{sub L}) exposed to cesium-137 gamma radiation: Effect of caffeine  

SciTech Connect

We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian A{sub L} human-hamster hybrid cells exposed to {sup 137}Cs {gamma} radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1{sup {minus}} mutants by {sup 137}Cs {gamma} radiation. Molecular analysis of 235 S1{sup {minus}} mutants using a series of DNA probes mapped to the human chromosome 11 in the A{sub L} hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, {sup 137}Cs {gamma} rays alone or {sup 137}Cs {gamma} rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These {open_quotes}complex{close_quotes} mutations were rare for {sup 137}Cs {gamma} irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by {sup 137}Cs {gamma} irradiation. 62 refs., 3 figs., 3 tabs.

McGuinness, S.M.; Shibuya, M.L.; Ueno, A.M. [Colorado State Univ., Fort Collins, CO (United States)] [and others

1995-06-01

381

Teaching about Natural Background Radiation  

ERIC Educational Resources Information Center

Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also…

Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

2013-01-01

382

Design of a spreader bar crane-mounted gamma-ray radiation detection system  

NASA Astrophysics Data System (ADS)

Over 95% of imports entering the United States from outside North America arrive by sea at 329 ports of entry. These imports are packaged in more than 11 million cargo containers. Radiation portals monitors routinely scan cargo containers leaving port on specially-designed trucks. To accelerate the process, some commercial entities have placed detection systems on the spreader-bar cranes (SBCs) used to offload. Little is known about the radiation background profiles of systems operating on these cranes. To better understand the operational characteristics of these radiation detection systems; a research team from Texas A&M University (TAMU) mounted three thallium-doped sodium iodide [NaI(Tl)] detectors on an SBC at the Domestic Nuclear Detection Office's (DNDO) test track facility at the Port of Tacoma (PoT). These detectors were used to monitor background radiation levels and continuously recorded data during crane operations using a custom-built software package. Count rates and spectral data were recorded for various crane heights over both land and water. The results of this research created a background profile in which count rate was heavily dependent on position demonstrating how detector readings changed in the operational environment.

Grypp, Matthew D.; Marianno, Craig M.; Poston, John W.; Hearn, Gentry C.

2014-04-01

383

Energy resolution in semiconductor gamma radiation detectors using heterojunctions and methods of use and preparation thereof  

DOEpatents

In one embodiment, a system comprises a semiconductor gamma detector material and a hole blocking layer adjacent the gamma detector material, the hole blocking layer resisting passage of holes therethrough. In another embodiment, a system comprises a semiconductor gamma detector material, and an electron blocking layer adjacent the gamma detector material, the electron blocking layer resisting passage of electrons therethrough, wherein the electron blocking layer comprises undoped HgCdTe. In another embodiment, a method comprises forming a hole blocking layer adjacent a semiconductor gamma detector material, the hole blocking layer resisting passage of holes therethrough. Additional systems and methods are also presented.

Nikolic, Rebecca J.; Conway, Adam M.; Nelson, Art J.; Payne, Stephen A.

2012-09-04

384

Study of a number of biochemical indices of the blood and tissue of dogs after prolonged gamma-radiation  

NASA Technical Reports Server (NTRS)

The glucose content in blood and the lipid content in serum and tissues of dogs exposed to chronic radiation for 3 and 5 years were studied. In tissues of these animals, the concentration of soluble DNA and DNA contained in DNP was studied in the spleen, lymph node (deep cervical node) and bone marrow of thigh bones. Results indicate that chronic gamma irradiation significantly changes concentrations of glucose in the blood, and that of several lipids in serum and tissues. A reduction in the concentration of DNP in tested organs reflects changes in the relative number of cells with various nuclear cytoplasmic ratios; most pronounced changes in biochemical indices occur in dogs exposed to chronic gamma radiation in doses of 125 rad per year.

Alers, I.; Alersova, E.; Praslichka, T.; Mishurova, E.; Sedlakova, A.; Malatova, Z.; Akhunov, A. A.; Markelov, B. A.

1974-01-01

385

Reduction of toxicity of antimicrobial compounds by degradation processes using activated sludge, gamma radiation, and UV.  

PubMed

The occurrence and persistence of pharmacologically active compounds in the environment has been an increasingly important issue. The objectives of this study were to investigate the decomposition of aqueous antimicrobial compounds using activated sludge, ?-irradiation, and UV treatment, and to evaluate the toxicity towards green algae, Pseudokirchneriella subcapitata, before and after treatment. Tetracycline (TCN), lincomycin (LMC) and sulfamethazine (SMZ) were used as target compounds. Gamma (?)-irradiation showed the highest removal efficiency for all target compounds, while UV and activated sludge treatment showed compound-dependent removal efficiencies. TCN and SMZ were well degraded by all three treatment methods. However, LMC showed extremely low removal efficiency for UV and activated sludge treatments. Overall, the algal toxicity after degradation processes was significantly decreased, and was closely correlated to removal efficiency. However, in the case of ?-irradiated TCN, UV and activated sludge treated LMC as well as sludge treated SMZ, the observed toxicity was higher than expected, which indicates the substantial generation of byproducts or transformed compounds of a greater toxicity in the treated sample. Consequently, ?-radiation treatment could be an effective method for removal of recalcitrant compounds such as antibiotics. PMID:24083903

Kim, Hyun Young; Jeon, Junho; Yu, Seungho; Lee, Myunjoo; Kim, Tae-Hun; Kim, Sang D

2013-11-01

386

Gamma and electron beam radiation induced physico-chemical modifications of poly(propylene)  

NASA Astrophysics Data System (ADS)

The homopolymer PP, a plastic material used as packaging and for medical products, must be subjected to a form of sterilization. Nowadays, one kind of this technology uses ionising radiation, which can be ?-rays or electron beams. In order to study the structural modifications of polymer syringes which could occur following these treatments at different doses (25-150 kGy), several analytical techniques have been used. DSC provided information on changes in the cristallinity of the polymer. The thermal evaluation was supplemented by testing the rheological properties of polypropylene. In addition, Reversed Phase Liquid Chromatography (HPLC) with a quaternary elution gradient was carried out for the evaluation of the degradation of the additives. Thermogravimetric analysis (TGA) coupled with Fourier transform infrared (TGA/FTIR) was used to measure the desorption of food simulating liquid (CH 2Cl 2). First, the results obtained proved that the ?-rays as well as the electron beam induced degradation of the polymer and its additives. Next, we compared the effects of gamma and electron beam irradiation to determine which of these two processes better maintained the integrity of the irradiated product.

Yagoubi, N.; Peron, R.; Legendre, B.; Grossiord, J. L.; Ferrier, D.

1999-05-01

387

[The of gamma-radiation for induction of apomixis in sea-buckthorn (Hippophaë rhamnoides L.)].  

PubMed

The results of studying of the induced apomixis in pollen of sea-buckthorn irradiated by the 60Co gamma-Radiation are considered. Was established that the most effective dose for pollination of the experimental plants is 50 k Gy. In total, from 46 seedlings 19 cases of apomictic origin were revealed, 7 individuals were found to be haploid (n = = 12) and 19 ones were diploid (2n = 24) of maternal origin. Was supposed that apomictic plants (19 seedlings) have parthenogenetic origin. The reason for such conclusion is that the irradiated anomalous pollen tubes despite not having spermia, are entering embryo sac and stimulate the development of apomictic embryo from non-fertilized female gametes. Apparently, pollen tubes cause the induction of DNA replication in the ovules and the development of parthenogenetic plants. Consequently, the described method can be used for the regulation of parthenogenesis in sea-buckthorn to change natural ratio (1 : 1) of male to female plants in desirable quantity. PMID:17323696

Todya, V A; Chankseliani, Z Zh; Mchedlishvili, M V

2006-01-01

388

Electroweak radiative corrections to $W^+W^-\\gamma$ production at the ILC  

E-print Network

We provide and discuss the precision predictions for the $W^+W^-\\gamma$ production at the ILC including the full electroweak (EW) one-loop corrections and high order initial state radiation (ISR) contributions in the Standard Model. The dependence of the leading order (LO) and EW corrected cross sections on the colliding energy is investigated. We find that the EW correction suppresses the LO cross section significantly, and the ISR effect beyond ${\\cal O}(\\alpha)$ is important near the threshold, but is negligible in the high energy region. We provide the LO and EW corrected distributions of the transverse momenta and rapidities of final $W^-$-boson and photon as well as the $W$-pair invariant mass. From the various kinematic distributions, we find that EW correction strongly depends on the final state phase space. We investigate the leptonic decays of the final W-boson pair by adopting the narrow width approximation (NWA), and find that the final produced photon and leptons can be well separated from each o...

Chong, Chen; Ren-You, Zhang; Yu, Zhang; Liang-Wen, Chen; Lei, Guo

2014-01-01

389

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

PubMed Central

Effects of radiation on sensing and data transmission components are of great interest in many applications including homeland security, nuclear power generation, and military. A new type of microstructured optical fiber (MOF) called the random hole optical fiber (RHOF) has been recently developed. The RHOFs can be made in many different forms by varying the core size and the size and extent of porosity in the cladding region. The fibers used in this study possessed an outer diameter of 110 ?m and a core of approximately 20 ?m. The fiber structure contains thousands of air holes surrounding the core with sizes ranging from less than 100 nm to a few ?m. We present the first study of the behavior of RHOF under gamma irradiation. We also propose, for the first time to our knowledge, an ionizing radiation sensor system based on scintillation light from a scintillator phosphor embedded within a holey optical fiber structure. The RHOF radiation response was compared to normal single mode and multimode commercial fibers (germanium doped core, pure silica cladding) and to those of radiation resistant fibers (pure silica core with fluorine doped cladding fibers). The comparison was done by measuring radiation-induced absorption (RIA) in all fiber samples at the 1550 nm wavelength window (1545 ± 25 nm). The study was carried out under a high-intensity gamma ray field from a 60Co source (with an exposure rate of 4×104 rad/hr) at an Oak Ridge National Laboratory gamma ray irradiation facility. Linear behavior, at dose values < 106 rad, was observed in all fiber samples except in the pure silica core fluorine doped cladding fiber which showed RIA saturation at 0.01 dB. RHOF samples demonstrated low RIA (0.02 and 0.005 dB) compared to standard germanium doped core pure silica cladding (SMF and MMF) fibers. Results also showed the possibility of post-fabrication treatment to improve the radiation resistance of the RHOF fibers.

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

2007-01-01

390

DNA repair after gamma radiation and superoxide dismutase activity in lymphocytes from subjects of far advanced age  

Microsoft Academic Search

DNA repair after gamma radiation was studied in purified T lymphocytes from young and aged subjects. Two different assays were employed. In the first, T lymphocytes were stimulated with phytohemagglutinin (PHA) for 72 h and then treated with hydroxyurea, irradiated with 30 K rads and pulsed with (³H)thymidine (TdR) for 4 h. In the second, T lymphocytes were first irradiated

Federico Licastro; Claudio Franceschi; M. G. Battelli; Pierluigi Tabacchi; Marinella Cenci; Francesco Barboni; Domenico Pallenzona

1982-01-01

391

Alkylation and dimerisation of 2,6-substituted phenols induced by cobalt-60 gamma radiation in hydrocarbons Part I. Alkylation  

NASA Astrophysics Data System (ADS)

The behavior of 2, 6-substituted phenols in hydrocarbons under the influence of gamma radiation and in the absence of oxygen was studied. Thus 2-methyl-6-tert. butyl phenol in isooctane solution was alkylated in the position 4 and 2-methyl-4-/1, 1, 3, 3- tetramethylbutyl/ -6-tert. butylphenol was formed at a conversion 33%. Among the products also 3, 3-'dimethyl-5, 5-ditert. butyl-4, 4-'biphenyldiol was found. Radiation yields were calculated and some reactions of the alkylation mechanism were proposed.

Chutný, B.; Brodilová, J.; Pospíšil, J.

392

Crystal growth and thermoluminescence response of NaZr2(PO4)3 at high gamma radiation doses  

NASA Astrophysics Data System (ADS)

This work describes the synthesis and characterization of NaZr2(PO4)3. The stability of this material under high doses of gamma radiation was investigated in the range of 10-50 MGy. Samples of unaltered and gamma irradiated NaZr2(PO4)3 were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermoluminescence. The results showed that while functional groups were not affected by the gamma irradiation, morphology changes were observed with increasing doses of gamma irradiation. The morphology of the non-irradiated compound is agglomerated flakes; however, irradiation at 10 MGy splits the flakes inducing the formation of well-defined cubes. Gamma irradiation induced the crystal size of the NaZr2(PO4)3 to grow. The heat treatment (973 K) of samples irradiated at 50 MGy resulted in the recovery of the original morphology. Furthermore, the thermoluminescence analysis of the irradiated compound is reported.

Ordóñez-Regil, E.; Contreras-Ramírez, A.; Fernández-Valverde, S. M.; González-Martínez, P. R.; Carrasco-Ábrego, H.

2013-11-01

393

B1 Sequence-Based Real-Time Quantitative PCR: A Sensitive Method for Direct Measurement of Mouse Plasma DNA Levels After Gamma Irradiation  

SciTech Connect

Purpose: Current biodosimetric techniques for determining radiation exposure have inherent delays, as well as quantitation and interpretation limitations. We have identified a new technique with the advantage of directly measuring circulating DNA by amplifying inter-B1 regions in the mouse genome, providing a sensitive method for quantitating plasma DNA. Methods and Materials: Real-time quantitative polymerase chain reaction (PCR) was used to detect levels of DNA by amplifying inter-B1 genomic DNA in plasma samples collected at 0-48 h from mice receiving 0-10 Gy total- or partial-body irradiation ({sup 137}Cs {gamma}-ray source at {approx}1.86 Gy/min; homogeneity: {+-} 6.5%). Results: The correlation coefficient between DNA levels and the threshold cycle value (C{sub T}) was 0.996, and the average recoveries of DNA in the assay were 87%. This assay revealed that when BALB/c mice were exposed to 10 Gy total-body irradiation (TBI), plasma DNA levels gradually increased beginning at 3 h after irradiation, peaked at 9 h, and returned to baseline within 48 h. Increased plasma DNA levels were also detected following upper-torso or lower-torso partial-body irradiation; however, TBI approximately doubled those plasma DNA levels at the same radiation dose. This technique therefore reflects total body cell damage. The advantages of this assay are that DNA extraction is not required, the assay is highly sensitive (0.002 ng), and results can be obtained within 2.5 h after collection of plasma samples. Conclusions: A radiation dose-dependent increase of plasma DNA was observed in the dose range from 2 to 10 Gy, suggesting that plasma DNA may be a useful radiation biomarker and adjunct to existing cell-based assays.

Zhang Hengshan; Zhang, Steven B.; Sun Weimin; Yang Shanmin; Zhang Mei; Wang Wei; Liu Chaomei; Zhang Kunzhong; Swarts, Steven; Fenton, Bruce M.; Keng, Peter; Maguire, David [Department of Radiation Oncology, University of Rochester School of Medicine and Dentistry, Rochester, NY (United States); Okunieff, Paul [Department of Radiation Oncology, University of Rochester School of Medicine and Dentistry, Rochester, NY (United States)], E-mail: Paul_Okunieff@URMC.Rochester.edu; Zhang Lurong [Department of Radiation Oncology, University of Rochester School of Medicine and Dentistry, Rochester, NY (United States)

2009-08-01

394

Gamma Radiation Monitoring Through Thin Film of ClAlPc Doped With TiO{sub 2}  

SciTech Connect

Chloroaluminum phthalocyanine (ClAlPc) synthesized by adopting focused microwave synthesis approach was doped with nanocrystalline TiO{sub 2} (5% by weight) and developed into the thin film sandwiched device having ITO/ClAlPc:TiO{sub 2}/Ag Schottky configuration by spin coating technique covering 1 cm{sup 2} as an active area. The so fabricated device having initial dark current of the order of 0.2 5 m A was exposed to variable dose of gamma radiation ranging from lcGy to 10 Gy at a dose rate of 1 Gy/hour. The experimental observation reveals the generation of localized traps leading to structural disorder within the solid material. Doping with TiO{sub 2} enhances the surface area of the film which in tern improves sensitivity of device to wider dose rage. Exposure of the device to variable dose of gamma radiation imparts decrease in forward bias current and capacitance characteristics with increase in radiation dose. Also, absorbance characteristics of the Al Pc: TiO{sub 2} was analyzed before and after exposure to radiation which reveals that absorbance decreases with radiation dose leading to decrease in optical band gap.

Roy, M. S.; Gautam, A. K.; Kumar, M.; Prasad, N.; Janu, Y.; Deol, Y. S.; Mishra, R. K.; Choudhary, G. R.; Sadh, A. K. [Radiation processing and Device Group, Defence Laboratory, Jodhpur-342 011, Rajasthan (India)

2008-04-23

395

Effect of compound K, a metabolite of ginseng saponin, combined with gamma-ray radiation in human lung cancer cells in vitro and in vivo.  

PubMed

Pretreatment of NCI-H460 human lung cancer cells with compound K produced by intestinal bacteria enhances gamma-ray radiation-induced cell death. Increases in apoptosis induced by combined treatment are made apparent in the observation of nuclear fragmentation, loss of mitochondrial membrane potential (Deltapsi), and activation of caspase 3. Apoptosis induced by compound K and gamma-ray radiation is associated with reactive oxygen species (ROS) generation. Furthermore, compound K, in combination with gamma-ray radiation, has an enhanced effect in the regression of NCI-H460 tumor xenografts of nude mice. These results suggest that compound K has possible application for cancer therapy when used in combination with gamma-ray radiation. PMID:19526988

Chae, Sungwook; Kang, Kyoung Ah; Chang, Weon Young; Kim, Min Jung; Lee, Su Jae; Lee, Yun Sil; Kim, Hee Sun; Kim, Dong Hyun; Hyun, Jin Won

2009-07-01

396

Use of gamma Radiation as a Form of Preservation of Sweet Potatoes: Phase 2: Final Report for Period January 1, 1986-December 31, 1986.  

National Technical Information Service (NTIS)

Effects of gamma radiation and storage time on storage roots of 'Georgia Jet' and 'Jewel' sweet potatoes and on the sweetpotato weevil Cylas formicarius elegantulus (Summers) were studied. The storage roots were irradiated: immediately after harvest and b...

M. E. M. Tolbert, P. A. Loretan

1987-01-01

397

Investigation of the soil-plant transfer of primordial radionuclides in tomatoes by low-level gamma-ray spectrometry.  

PubMed

The paper presents actual data from investigations of the soil-plant transfer of the primordial radionuclides 40K, 238U, 226Ra, 210Pb and 227Ac for tomatoes growing at soils from former uranium mining areas. The analysis were carried out using low-level gamma-ray spectrometry in a 47 m deep underground laboratory. For tomato fruits transfer factors of (0.0007 +/- 0.0006) for 235U, (0.0021 +/- 0.0017) for 226Ra, (0.0015 +/- 0.0009) for 210Pb and (0.0018 +/- 0.0012) for 227Ac were obtained. The investigation of the soil-plant transfer by low-level gamma-ray spectrometry is often limited by the Compton-continuum from the always present high-energy gamma-ray emitter 40K. PMID:10879862

Köhler, M; Gleisberg, B; Niese, S

2000-01-01

398

Combined effect of gamma radiation and Perovskia atriplicifolia for the control of red flour beetle, Tribolium castaneum.  

PubMed

In order to explore an effective and safe pesticide that could be coupled up with irradiation method, the present study was conducted to determine the synergistic effects of gamma radiation with an essential oil from Perovskia atriplicifolia (Benth) on Tribolium castaneum (Herbst) as a main stored-product pest. Adult insects were exposed to sub lethal doses of gamma radiation and P. atriplicifolia oil, and the mortality was assessed in a short time period after treatment. There was a significant synergistic effect of exposure to gamma radiation and essential oil on 1-7 days old adults of T. castaneum. The potential toxicity of the essential oil on irradiated adults at 900 Gy was synergistically increased. When irradiated adults were exposed to LD5, LD25 and LD50 values of the oil the mortality was increased 8.5, 13.0 and 16.0 times respectively. This combination of irradiation would have a low environmental impact and high compatibility with P. atriplicifolia. PMID:19226806

Ahmadi, M; Moharramipour, S; Mozdarani, H; Negahban, M

2008-01-01

399

Dietary L-methionine supplementation mitigates gamma-radiation induced global DNA hypomethylation: enhanced metabolic flux towards S-adenosyl-L-methionine (SAM) biosynthesis increases genomic methylation potential.  

PubMed

The objective of this study was to examine the effect of (60)Co-gamma (?) radiation on modulation of genomic DNA methylation, if any, of mice maintained (6 weeks) on normal control diet (NCD) and L-methionine supplemented diet (MSD). To elucidate the possible underlying mechanism(s), we exposed the animals to ?-radiation (2, 3 and 4 Gy) and investigated the profile of downstream metabolites and enzymes involved in S-adenosyl-L-methionine (SAM) generation. Liver samples were also subjected to histopathological examinations. Compared to NCD fed and irradiated animals, hepatic folate, choline and L-methionine levels decreased moderately, while hepatic SAM levels increased in MSD fed and irradiated animals. Under these conditions, a marked modulation of methionine adenosyltransferase (MAT) and L-methionine synthase (MSase) activities was observed. Concomitant with increase in liver SAM pool, increased DNA methyltransferase (dnmt) activity in MSD fed mice indicated enhanced metabolic flux towards DNA methylation. Further results showed that genomic DNA methylation and 5-methyl-2'-deoxy cytidine residues were maintained at normal levels in MSD fed and irradiated mice compared to NCD fed and irradiated animals. In conclusion, our results suggest that increasing supply of preformed methyl groups, via dietary L-methionine supplementation might significantly increase methylation potential of radiation stress compromised DNA methylation cycle. PMID:24721433

Batra, Vipen; Verma, Poonam

2014-07-01

400

Management of defense beta-gamma contaminated solid low-level wastes  

SciTech Connect

In DOE defense operations, approx. 70,000 m/sup 3/ of beta-gamma low-level radioactive waste are disposed of annually by shallow land burial operations at six primary sites. Waste generated at other DOE sites are transported on public roads to the primary sites for disposal. In the practice of low-level waste (LLW) disposal in the US, the site hydrology and geology are the primary barriers to radioactive migration. To date, little emphasis has been placed on waste form improvements or engineered site modifications to reduce migration potential. Compaction is the most common treatment step employed. The performance of ground disposal of radioactive waste in this country, in spite of many practices that we would consider unacceptable in today's light, has resulted in very little migration of radioactivity outside site boundaries. Most problems with previously used burial grounds have been from subsidence at the arid sites and subsidence and groundwater contact at the humid sites. The radionuclides that have shown the most significant migration are tritium, /sup 90/Sr, and /sup 99/Tc. The unit cost for disposal operations at a given DOE site is dependent on many variables, but the annual volume to be disposed is probably the major factor. The average cost for current DOE burial operation is approximately $170/m/sup 3/. 23 figures.

Sease, J.D.

1983-01-01

401

Serum gamma-glutamyl transferase level is an independent predictor of incident hypertension in Korean adults.  

PubMed

The aim of our study was to assess the relationship between serum gamma-glutamyl transferase (GGT) level within the normal range and incident hypertension according to drinking and obesity status in nonhypertensive individuals. We followed up 4783 normotensive adults (mean age = 44 years) who had serum GGT levels within the normal range at baseline for 3 years. Subjects were divided into four GGT quartile groups according to their serum GGT level at baseline. The overall incidence of hypertension was 8.1%, and the incidence increased with increasing GGT quartile (3.8%, 6.9%, 9.0%, and 12.4% in the lowest, second, third, and highest GGT quartiles, respectively; P < .001). In the logistic regression analysis adjusted for age, sex, body mass index, lifestyle factors, glucose, uric acid, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, high-sensitivity C-reactive protein, and baseline systolic blood pressure, the odds ratio (ORs) for incident hypertension increased with increasing GGT quartile (P for trend = .030). In the above model, the highest quartile group showed increased ORs compared with those in the lowest quartile group (ORs [95% confidence interval], 2.638 [1.259-5.528]). Subgroup analyses revealed a significant association between GGT quartile and the incidence of hypertension in the drinker and non-overweight groups. Our results indicate that elevated serum GGT levels within the normal range are associated with a higher risk of incident hypertension in Korean adults, particularly, in drinkers and non-overweight individuals, suggesting possible different pathophysiologic mechanisms in the incidence of alcohol- and obesity-related hypertension. PMID:22471622

Kim, Nan Hee; Huh, Jung Kwon; Kim, Byung Jin; Kim, Min Woong; Kim, Bum Soo; Kang, Jin Ho

2012-01-01

402

Radioactivity Levels and Gamma-Ray Dose Rate in Soil Samples from Kohistan (Pakistan) Using Gamma-Ray Spectrometry  

NASA Astrophysics Data System (ADS)

The analysis of naturally occurring radionuclides (226Ra, 232Th and 40K) and an anthropogenic radionuclide 137Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium (HPGe) detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges from 24.72 to 78.48Bq·kg-1 for 226Ra, 21.73 to 75.28Bq·kg-1 for 232Th, 7.06 to 14.9Bq·kg-1 for 137Cs and 298.46 to 570.77Bq·kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq·kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report (370Bq·kg-1). Man-made radionuclide 137Cs is also present in detectable amount in all soil samples. Presence of 137Cs indicates that the samples in this remote area also receive some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.

Hasan, M. Khan; Ismail, M.; K., Khan; Akhter, P.

2011-01-01

403

Effect of 1.33 Mev gamma radiation and 0.5 Mev electrons on the mechanical properties of graphite fiber composites  

NASA Technical Reports Server (NTRS)

Epoxy/graphite fiber, polyimide/graphite fiber, and polysulfone/graphite fiber composites were exposed to 1.33 Mev gamma irradiation and 0.5 Mev electron bombardment for varying periods of time. The effects of the irradiation treatments on the breaking stress and Young's modulus were studied by a three point bending test. Effects were small; both electron radiation up to 5000 Mrad and gamma radiation up to 350 Mrad resulted in slight increases in both stress and modulus.

Fornes, R. E.; Memory, J. D.; Naranong, N.

1982-01-01

404

Sensory evaluation by gamma radiation effect on protein allergen of laying hen eggs  

NASA Astrophysics Data System (ADS)

Although considered the most complete food and nutritionally shown to be part of a healthy diet, the egg is the source of many eating disorders, especially for infants. Irradiation has been used in studies not only as a means of microbiological control, but also on its structural action in the substances molecules and has been used to reduce the allergenic effects. The aim of this study was to evaluate the sensory effects of Co60 gamma radiation on proteins, enabling the acceptability of allergy food for genetically intolerant people. Eggs commercial fresh and freeze-dried and subjected to gamma irradiation by Co60 source at doses 0 (control), 10 kGy; 20 kGy and 30 kGy and rates of doses of 19.4 kGy/h and 31.8 kGy/h. Acceptability test was used by the hedonic scale, since it is necessary to know the "affective status" of consumers for the product, implying a preference, i.e. the most preferred samples are the most accepted and vice versa. The samples were presented as the habit of consumption (cooked) to a group of 41 adults panelists of both gender, aged from 21 to 40 years, and served under complete block design balanced with respect to the order of presentation. The evaluated attributes was flavor, appearance and overall acceptability. In general, for boiled eggs and freeze-dried, it was observed that the control sample was the most acceptable, followed by the sample irradiated with 10 kGy in both dose rates. In addition, panelists presented in testimony that they found interesting changes due to irradiation; also said they would not buy the product because of the marked change in appearance and smell, which at one point he ended up in disgust and detract from sales of the product, but they would buy irradiated with 10 kGy in both dose rate and dose of 20 kGy at a dose rate of 19.4 kGy/h.

Harder, M. N. C.; Arthur, V.; Perina, V. C. S.; Silva, L. C. A. S.; Bortoleto, G. G.

2012-08-01

405

Charged-particle induced radiation damage of a HPGe gamma-ray detector during spaceflight  

NASA Astrophysics Data System (ADS)

The Mars Observer spacecraft was launched on September 26, 1992 with a planned arrival at Mars after an 11-month cruise. Among the scientific instruments carried on the spacecraft was a Gamma-Ray Spectrometer (GRS) experiment to measure the composition of Mars. The GRS used a passively cooled high-purity germanium detector for measurements in the 0.2-10MeV region. The sensor was a closed-end co-axial detector, 5.5cm diameter by 5.5cm long, and had an efficiency along its axis of 28% at 1332keV relative to a standard NaI(Tl) detector. The sensor was surrounded by a thin (0.5cm) plastic charged-particle shield. This was the first planetary mission to use a cooled Ge detector. It was expected that the long duration in space of three years would cause an increase in the energy resolution of the detector due to radiation damage and could affect the expected science return of the GRS. Shortly before arrival, on August 21, 1993, contact was lost with the spacecraft following the pressurization of the propellent tank for the orbital-insertion rocket motor. During much of the cruise to Mars, the GRS was actively collecting background data. The instrument provided over 1200h of data collection during periods of both quiescent sun and solar flares. From the charged particle interactions in the shield, the total number of cosmic ray hits on the detector could be determined. The average cosmic ray flux at the MO GRS was about 2.5cm-2s-1. The estimated fluence of charged particles during cruise was about 108 particles cm-2 with 31% of these occurring during a single solar proton event of approximately 10 days duration. During cruise, the detector energy resolution determined from a background gamma-ray at 1312keV degraded from 2.4keV full-width at half-maximum shortly after launch to 6.4keV 11 months later. This result agrees well with measurements from ground-based accelerator irradiations (at 1.5GeV) on a similar size detector.

Evans, L. G.; Starr, R.; Brückner, J.; Boynton, W. V.; Bailey, S. H.; Trombka, J. I.

1999-02-01

406

The low dose gamma ionising radiation impact upon cooperativity of androgen-specific proteins.  

PubMed

The paper deals with effects of the ionising radiation (?-IR, 0.5 Gy) upon serum testosterone (T), characteristics of testosterone-binding globulin (TeBG) and androgen receptor (AR) in parallel with observation of androgen (A) responsive enzyme activity - hexokinase (HK). The interdependence or relationships of T-levels with parameters of the proteins that provide androgenic regulation are consequently analyzed in post-IR dynamics. The IR-stress adjustment data reveal expediency of TeBG- and AR-cooperativity measurements for more precise assessments of endocrine A-control at appropriate emergencies. PMID:23465891