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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

Measurements of gamma radiation levels and spectra in the San Francisco Bay Area  

NASA Astrophysics Data System (ADS)

Much of the radiation received by an average person is emitted by naturally-occurring radioactive isotopes from the thorium, actinium, and uranium decay series, or potassium. In this study, we have measured gamma radiation levels at various locations in the San Francisco Bay Area and the UC Berkeley campus from spectra taken using an ORTEC NOMAD portable data acquisition system and a large-volume coaxial HPGe detector. We have identified a large number of gamma rays originating from natural sources. The most noticeable isotopes are ^214Bi, ^40K, and ^208Tl. We have observed variations in counting rates by factors of two to five between different locations due to differences in local conditions -- such as building, concrete, grass, and soil compositions. In addition, in a number of outdoor locations, we have observed 604-, 662-, and 795-keV gamma rays from ^134,137Cs, which we attribute to fallout from the recent Fukushima reactor accident. The implications of these results will be discussed.

Lo, B. T.; Brozek, K. P.; Angell, C. T.; Norman, E. B.

2011-10-01

3

Non Invasive Water Level Monitoring on Boiling Water Reactors Using Internal Gamma Radiation: Application of Soft Computing Methods  

SciTech Connect

To provide best knowledge about safety-related water level values in boiling water reactors (BWR) is essentially for operational regime. For the water level determination hydrostatic level measurement systems are almost exclusively applied, because they stand the test over many decades in conventional and nuclear power plants (NPP). Due to the steam generation especially in BWR a specific phenomenon occurs which leads to a water-steam mixture level in the reactor annular space and reactor plenum. The mixture level is a high transient non-measurable value concerning the hydrostatic water level measuring system and it significantly differs from the measured collapsed water level. In particular, during operational and accidental transient processes like fast negative pressure transients, the monitoring of these water levels is very important. In addition to the hydrostatic water level measurement system a diverse water level measurement system for BWR should be used. A real physical diversity is given by gamma radiation distribution inside and outside the reactor pressure vessel correlating with the water level. The vertical gamma radiation distribution depends on the water level, but it is also a function of the neutron flux and the coolant recirculation pump speed. For the water level monitoring, special algorithms are required. An analytical determination of the gamma radiation distribution outside the reactor pressure vessel is impossible due to the multitude of radiation of physical processes, complicated non-stationary radiation source distribution and complex geometry of fixtures. For creating suited algorithms Soft Computing methods (Fuzzy Sets Theory, Artificial Neural Networks, etc.) will be used. Therefore, a database containing input values (gamma radiation distribution) and output values (water levels) had to be built. Here, the database was established by experiments (data from BWR and from a test setup) and simulation with the authorised thermo-fluid code ATHLET. (authors)

Fleischer, Sebastian; Hampel, Rainer [University of Applied Sciences Zittau/Goerlitz, Theodor-Koerner-Str. 16, D-02763 Zittau (Germany)

2006-07-01

4

Study of radiation dose induced by cosmic-ray origin low-energy gamma rays and electrons near sea level  

NASA Astrophysics Data System (ADS)

For a long time, it has been known that low-energy continuous gamma radiation is present in open air at the Earth's surface. In previous investigations it was assumed that this radiation is produced almost exclusively by gamma photons emitted due to the natural radioactivity, which are backscattered by air above ground. We show that significant amount of this radiation (related to energy region 30-300 keV) that peaks at about 90 keV, is produced by cosmic-rays, with the photon flux of about 3000 m-2 s-1. We find that the contribution of this omnipresent low-energy gamma radiation of cosmic-ray origin, including the corresponding low-energy electron flux, to the doses of general population are non-negligible components of overall doses induced by cosmic rays near sea level.

Mrdja, D.; Bikit, I.; Bikit, K.; Slivka, J.; Anicin, I.

2015-02-01

5

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

6

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

7

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

8

Natural gamma radiation map (MARNA) and indoor radon levels in Spain.  

PubMed

During the last decade, the Department of Applied and Medical Physics has been involved in the development of a radiation protection programme. In the framework of this programme, measurements of indoor radon, principally, have been carried out nationwide. Geometric mean radon concentrations of 45 Bq m(-3) in the whole country and 130 Bq m(-3) in the high natural radiation area have been estimated. On the other hand, the so-called MARNA Project is developed into the framework of an agreement subscribed between the Spanish Nuclear Safety Council (CSN) and the National Uranium (ENUSA), the first phase of which has been the elaboration of the Natural Gamma Radiation Map of Spain on the scale of 1:1,000,000 using radiometric data generated in the 30 years of the lifetime of the ancient National Uranium Exploration and Investigation Plan mainly through airborne, carborne, and by foot surveys, within the MARNA Project itself. The lowest averaged dose rate from external gamma radiation (19.3 nGyh(-1)) was found in carbonate bedrock and the highest (87.7 nGyh(-1)) was found in granite and clay bedrock. This paper summarizes the main results obtained from the measurements performed in both projects, with special interest in those concerning the correlation between the data reported in order to conclude about the potential benefit of the MARNA maps in the definition of affected areas in the country. PMID:14680892

Quindós Poncela, L S; Fernández, P L; Gómez Arozamena, J; Sainz, C; Fernández, J A; Suarez Mahou, E; Martin Matarranz, J L; Cascón, M C

2004-02-01

9

Probable Level Densities and Radiative Strength Functions of Dipole gamma-Transitions in 57Fe Compound Nucleus  

E-print Network

From the published results of experimental research of 56Fe(n,2gamma) reaction carried out in Budapest, the values of the most probable densities of cascade intermediate levels with 1/2, 3/2 spin and radiative strength functions of cascade E1 and M1 transitions in 57Fe compound nucleus have been determined. These results correspond to analogous data for other nuclei studied by us and contradict to predictions of conventional models.

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

2005-08-09

10

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

11

Estimation of the value and localization of possible systematic errors in determination of level density and radiative strength functions from the (n,2gamma) -reaction  

E-print Network

Systematic error in determination of the absolute intensities of the two-step gamma-cascades after the thermal neutron capture and its influence on the value and localization of extracted from (n,2gamma)-reaction probable level densities and radiative strength functions of dipole gamma-transitions have been analysed. It was found that this error in limits of its possible magnitude cannot change made earlier conclusions about the radiative strength functions of E1- and M1- transitions at Egamma ~ 3 MeV and level density of heavy nucleus below ~0.5Bn.

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

2004-04-23

12

Natural gamma radiation map (MARNA) and indoor radon levels in Spain  

Microsoft Academic Search

During the last decade, the Department of Applied and Medical Physics has been involved in the development of a radiation protection programme. In the framework of this programme, measurements of indoor radon, principally, have been carried out nationwide. Geometric mean radon concentrations of 45 Bq m?3 in the whole country and 130 Bq m?3 in the high natural radiation area

L. S. Quindós Poncela; P. L. Fernández; J. Gómez Arozamena; C. Sainz; J. A. Fernández; E. Suarez Mahou; J. L. Martin Matarranz; M. C. Cascón

2004-01-01

13

Diffuse gamma radiation  

NASA Technical Reports Server (NTRS)

An examination of the intensity, energy spectrum, and spatial distribution of the diffuse gamma-radiation observed by SAS-2 satellite away from the galactic plane in the energy range above 35 MeV has shown that it consists of two components. One component is generally correlated with galactic latitudes, the atomic hydrogen column density was deduced from 21 cm measurements, and the continuum radio emission, believed to be synchrotron emission. It has an energy spectrum similar to that in the plane and joins smoothly to the intense radiation from the plane. It is therefore presumed to be of galactic origin. The other component is apparently isotropic, at least on a coarse scale, and has a steep energy spectrum. No evidence is found for a cosmic ray halo surrounding the galaxy in the shape of a sphere or oblate spheroid with galactic dimensions. Constraints for a halo model with significantly larger dimensions are set on the basis of an upper limit to the gamma-ray anisotropy.

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

1977-01-01

14

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

15

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

16

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

17

Radiation levels during operation  

Microsoft Academic Search

For full-power operation, the four major sources of radiation are: neutrons and gamma rays penetrating the sides of the shield tank; nitrogen-16 activity in the primary coolant; radiation leakage up and down the space between the reactor vessel and shield tank and scattering to accessible areas; and gamma rays from inelastic scattering of fast neutrons in the core. These four

Maringas

1978-01-01

18

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

19

Measurement of terrestrial gamma radiation dose-rate (TGRD) level in soil samples from the district of Rembau, Malaysia, using high-purity Germanium detectors  

NASA Astrophysics Data System (ADS)

This study assesses the gamma radiation levels and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected from the district of Rembau, Malaysia using High-purity Germanium (HPGe) Detectors. A 105 measurement were performed on surface soil using NaI (Tl) gamma-ray detector with crystal size 1"x1", covering about 83% land of the Rembau district. The concentration of the naturally occurring radionuclides 232Th, 238U and 40K in soil samples collected were determined by using HPGe detector based on high-resolution gamma spectrometry system at Malaysia Nuclear Agency. The range of natural gamma radiation measured was from 114±14 nGy h?1 to 857±14 nGy h?1. The range of activity concentrations of U, Th and °K in soil from the studied areas varies from 151-401 Bq kg?1, 113-342 Bq kg?1 and 674-1526 Bq kg?1 with mean values of 245 Bq kg?1, 186 Bq kg?1 and 1152 Bq kg1 respectively. The mean values of terrestrial gamma radiation dose rate measured in Rembau district is 383±18 nGy h?1 compared to the Malaysian average is 92 nGy h?1 and world average is 59 nGy h?1 (UNSCEAR, 2000). The average annual dose from such terrestrial gamma radiation dose rates to an individual in Rembau district, assuming a tropical rural setting is estimated to be 0.78 mSv per year, which is considered to be within the normal range for doses from natural sources. An isodose map for the Rembau district has been plotted.

Norbani, N. E.; Abdullah Salim, N. A.; Rahman, A. T. Abdul

2014-11-01

20

SURVEY OF THE RADIATION LEVELS IN THE CONTAINMENT VESSEL OF THE ENRICO FERMI ATOMIC POWER PLANT. PART V. GAMMA RADIATION LEVELS ON THE OPERATING FLOOR OF THE CONTAINMENT BUILDING. a. LEVELS ABOVE THE EQUIPMENT COMPARTMENT. Technical Memorandum No. 16  

Microsoft Academic Search

The results are presented of a survey of calculated gamma-ray levels at ;\\u000a many points on the surface of the operating floor of the containment building for ;\\u000a the Enrico Fermi reactor. That portion of the floor surveyed lies directly above ;\\u000a the equipment compartment. The calculations were made with the aid of an IBM-650 ;\\u000a electronic computer. The main

W. F. Chaltron; H. E. Hungerford

1959-01-01

21

Gamma radiation characteristics of plutonium dioxide fuel  

NASA Technical Reports Server (NTRS)

Investigation of plutonium dioxide as an isotopic fuel for Radioisotope Thermoelectric Generators yielded the isotopic composition of production-grade plutonium dioxide fuel, sources of gamma radiation produced by plutonium isotopes, and the gamma flux at the surface.

Gingo, P. J.

1969-01-01

22

Cosmic Gamma-ray Background Radiation  

E-print Network

The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space telescope has recently measured it at 0.1-820 GeV and revealed that the cosmic GeV gamma-ray background is composed of blazars, radio galaxies, and star-forming galaxies. However, Fermi still leaves the following questions. Those are dark matter contribution, origins of the cosmic MeV gamma-ray background, and the connection to the IceCube TeV-PeV neutrino events. In this proceeding, I will review the current understandings of the cosmic gamma-ray background and discuss future prospects of cosmic gamma-ray background radiation studies. I also briefly review the current status of cosmic infrared/optical background radiation studies.

Inoue, Yoshiyuki

2014-01-01

23

Gamma radiation detectors for safeguards applications  

Microsoft Academic Search

The IAEA uses extensively a variety of gamma radiation detectors to verify nuclear material. These detectors are part of standardized spectrometry systems: germanium detectors for High-Resolution Gamma Spectrometry (HRGS); Cadmium Zinc Telluride (CZT) detectors for Room Temperature Gamma Spectrometry (RTGS); and NaI(Tl) detectors for Low Resolution Gamma Spectrometry (LRGS). HRGS with high-purity Germanium (HpGe) detectors cooled by liquid nitrogen is

R. Carchon; M. Moeslinger; L. Bourva; C. Bass; M. Zendel

2007-01-01

24

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

25

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

26

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

27

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

28

Gain without inversion for gamma radiation  

NASA Astrophysics Data System (ADS)

Gain without inversion for a level-mixing scheme is studied for gamma-optics. In this scheme nuclear level mixing is created by misalignment of a dc magnetic field with respect to the c-axis of a noncubic crystal. Axially symmetric electron nuclear coupling and nuclear quadrupole interaction with an electric field gradient produce two electro-nuclear levels that are equally mixed and split, with the energy gap dependent on the tilting angle of the magnetic field. By laser excitation of an electron transition, nuclear spin coherence can be created between these two levels. A condition is found for the predominant population of the dark state by spontaneous emission. This state is a particular superposition of the mixed states, such that, by selection rules, the transition from it cannot be excited by ?-radiation. If all absorbing nuclei are in the dark state, resonant ?-absorption is suppressed in the sample. At the same condition, ?-emission of the excited nuclei is allowed because the corresponding transition terminates in another component of the mixed states superposition. The constraints on the tilting angle and reciprocal gap between two mixed electro-nuclear levels are found, setting the limits to these values beyond which the gain without inversion becomes impossible.

Shakhmuratov, R. N.; Kozyreff, G.; Coussement, R.; Odeurs, J.; Mandel, P.

2000-05-01

29

Gamma radiation background measurements from Spacelab 2  

NASA Technical Reports Server (NTRS)

A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, Earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

1988-01-01

30

Gamma Radiation Doses In Sweden  

SciTech Connect

Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096{+-}0.019(1 SD) and 0.092{+-}0.016(1 SD){mu}Sv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11{+-}0.042(1 SD) and 0.091{+-}0.026(1 SD){mu}Sv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, {sup 222}Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings.

Almgren, Sara; Isaksson, Mats [Department of Radiation Physics, Goeteborg University, Sahlgrenska University Hospital, SE-413 45 Goeteborg (Sweden); Barregaard, Lars [Department of Occupational and Environmental Medicine, Sahlgrenska Hospital and Academy, SE-405 30 Goeteborg (Sweden)

2008-08-07

31

Gamma Radiation Effects on Peanut Skin Antioxidants  

PubMed Central

Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil. PMID:22489142

de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D’Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

2012-01-01

32

Gamma and electron radiation effects on straw  

NASA Astrophysics Data System (ADS)

Gamma and electron radiation effects on wheat straw, oat straw, barley straw and rye straw are reported. In vitro and in vivo studies show that the digestability of these agricultural rough materials can be increased up to 80% and more at high doses. The increase of the digestibility is connected with a depolymerisation of cellulose and hemicellulose.

Leonhardt, J. W.; Baer, M.; Huebner, G.; Hennig, A.; Nehring, K.

33

Inspection of cargo containers using gamma radiation  

NASA Astrophysics Data System (ADS)

This paper investigate, with the aid of Monte Carlo simulations and laboratory experiments, a technique for the detection of narcotics in large cargo containers using gamma-radiation. The transmission and back-scattering of photons, at different energies, is used to provide information useful for identifying the presence of bulk quantities of commonly encountered narcotics.

Hussein, Esam M. A.; Gokhale, Prasad; Arendtsz, Nina V.; Lawrence, Andre H.

1997-02-01

34

Gamma Radiation Induced Calibration Shift for Four Cryogenic Thermometer Types  

NASA Astrophysics Data System (ADS)

Cryogenic temperature sensors utilized in space environments are exposed to ionizing radiation with the total dose dependent upon the length of the mission. Based upon their minimal size and robust packaging, four models of cryogenic Resistance Thermometer Devices (RTDs) manufactured by Lake Shore Cryotronics, Inc. were tested to determine their reliability for space applications with regard to radiation. Samples of Cernox™ RTDs (CX-1050-SD), ruthenium oxide RTDs (models RX-102A-AA and RX-103A-AA), and silicon diode thermometers (model DT-670-SD) were irradiated at room temperature by a cesium-137 gamma source to total doses ranging from 5 Gy to 10 kGy. This paper presents the resulting temperature shifts induced by the gamma radiation as a function of total dose over the 1.4 K to 325 K temperature range. These data show that 1) Cernox™ RTDs exhibit high radiation hardness to 10 kGy from 1.4 K to 325 K, 2) ruthenium oxide RTDs show moderate radiation hardness to 10 kGy below 10 K, and 3) silicon diodes temperature sensors exhibit some radiation tolerance to low levels of radiation (especially below 70 K), but quickly shift calibration at radiation levels above 300 Gy, especially above 100 K.

Courts, S. Scott; Yeager, C. J.

2004-06-01

35

Composition and apparatus for detecting gamma radiation  

DOEpatents

A gamma radiation detector and a radioluminescent composition for use therein. The detector includes a radioluminescent 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. 3 figs.

Hofstetter, K.J.

1994-08-09

36

GammaCam{trademark} radiation imaging system  

SciTech Connect

GammaCam{trademark}, a gamma-ray imaging system manufactured by AIL System, Inc., would benefit a site that needs to locate radiation sources. It is capable of producing a two-dimensional image of a radiation field superimposed on a black and white visual image. Because the system can be positioned outside the radiologically controlled area, the radiation exposure to personnel is significantly reduced and extensive shielding is not required. This report covers the following topics: technology description; performance; technology applicability and alternatives; cost; regulatory and policy issues; and lessons learned. The demonstration of GammaCam{trademark} in December 1996 was part of the Large-Scale Demonstration Project (LSDP) whose objective is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) Chicago Pile-5 Research Reactor (CP-5). The purpose of the LSDP is to demonstrate that by using innovative and improved decontamination and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies.

NONE

1998-02-01

37

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

38

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

39

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

40

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

41

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

42

Health effects of low-level radiation in shipyard workers  

Microsoft Academic Search

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

Matanoski

1991-01-01

43

SSPM scintillator readout for gamma radiation detection  

NASA Astrophysics Data System (ADS)

Silicon-based photodetectors offer several benefits relative to photomultiplier tube-based scintillator systems. Solid-state photomultipliers (SSPM) can realize the gain of a photomultiplier tube (PMT) with the quantum efficiency of silicon. The advantages of the solid-state approach must be balanced with adverse trade-offs, for example from increased dark current, to optimize radiation detection sensitivity. We are designing a custom SSPM that will be optimized for green emission of thallium-doped cesium iodide (CsI(Tl)). A typical field gamma radiation detector incorporates thallium doped sodium iodide (NaI(Tl)) and a radiation converter with a PMT. A PMT's sensitivity peaks in the blue wavelengths and is well matched to NaI(Tl). This paper presents results of photomultiplier sensitivity relative to conventional SSPMs and discusses model design improvements. Prototype fabrications are in progress.

Baker, Stuart A.; Stapels, Christopher; Green, J. Andrew; Guise, Ronald E.; Young, Jason A.; Franks, Larry; Stokes, Britany; Wendelberger, Elizabeth

2011-09-01

44

Characterization of gamma radiation inducible thioredoxin h from Spirogyra varians.  

PubMed

In this study, thioredoxin h (Trxh) was isolated and characterized from the fresh water green alga Spirogyra varians, which was one amongst the pool of proteins induced upon gamma radiation treatment. cDNA clones encoding S. varians thioredoxin h were isolated from a pre-constructed S. varians cDNA library. Trxh had a molecular mass of 13.5kDa and contained the canonical WCGPC active site. Recombinant Trxh showed the disulfide reduction activity, and exhibited insulin reduction activity. Also, Trxh had higher 5,5'-dithiobis(2-nitrobenzoic acid) reduction activity with Arabidopsis thioredoxin reductase (TR) than with Escherichia coli TR. Specific expression of the Trxh gene was further analyzed at mRNA and protein levels and was found to increase by gamma irradiation upto the absorbed dose of 3kGy, suggesting that Trxh may have potential functions in protection of biomolecules from gamma irradiation. PMID:23830452

Yoon, Minchul; Yang, Ho-Yeon; Lee, Seung-Sik; Kim, Dong-Ho; Kim, Gwang-Hoon; Choi, Jong-il

2013-08-15

45

Satellite observation of atmospheric nuclear gamma radiation  

NASA Technical Reports Server (NTRS)

Satellite observations of the spectrum of gamma radiation from the earth's atmosphere in the energy interval from 300 keV to 8.5 MeV were obtained with a gamma-ray spectrometer during 1980-1983. A total of 20 atmospheric line features are superimposed on a continuum background which is modeled using a power law with an index of -1.16. The line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric N-14 and O-16. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, are explained by Compton scattering of the annihilation line photons in traversing an average of 21 g/sq cm of atmosphere.

Letaw, John R.; Share, G. H.; Kinzer, R. L.; Silberberg, R.; Chupp, E. L.

1989-01-01

46

Gamma radiation detectors for safeguards applications  

NASA Astrophysics Data System (ADS)

The IAEA uses extensively a variety of gamma radiation detectors to verify nuclear material. These detectors are part of standardized spectrometry systems: germanium detectors for High-Resolution Gamma Spectrometry (HRGS); Cadmium Zinc Telluride (CZT) detectors for Room Temperature Gamma Spectrometry (RTGS); and NaI(Tl) detectors for Low Resolution Gamma Spectrometry (LRGS). HRGS with high-purity Germanium (HpGe) detectors cooled by liquid nitrogen is widely used in nuclear safeguards to verify the isotopic composition of plutonium or uranium in non-irradiated material. Alternative cooling systems have been evaluated and electrically cooled HpGe detectors show a potential added value, especially for unattended measurements. The spectrometric performance of CZT detectors, their robustness and simplicity are key to the successful verification of irradiated materials. Further development, such as limiting the charge trapping effects in CZT to provide improved sensitivity and energy resolution are discussed. NaI(Tl) detectors have many applications—specifically in hand-held radioisotope identification devices (RID) which are used to detect the presence of radioactive material where a lower resolution is sufficient, as they benefit from a generally higher sensitivity. The Agency is also continuously involved in the review and evaluation of new and emerging technologies in the field of radiation detection such as: Peltier-cooled CdTe detectors; semiconductor detectors operating at room temperature such as HgI 2 and GaAs; and, scintillator detectors using glass fibres or LaBr 3. A final conclusion, proposing recommendations for future action, is made.

Carchon, R.; Moeslinger, M.; Bourva, L.; Bass, C.; Zendel, M.

2007-08-01

47

Effects of gamma-Radiation on Select Lipids and Antioxidants  

NASA Technical Reports Server (NTRS)

Radiation encountered on an extended duration space mission (estimates of 3 Sieverts for a mission to Mars) poses a threat not only to human health, but also to the quality, nutritional value, and palatability of the food system. Free radicals generated by radiation interaction with foods may initiate many unwanted reactions including: 1) autoxidation in lipids that alters flavor, odor, and concentrations of essential fatty acids, and 2) depletion of antioxidants food products and dietary supplements. Studies have shown that antioxidants may provide long term health protection from oxidative stress caused by radiation exposure; therefore, consumption of antioxidants will be important. Stability of essential fatty acids is also important for astronauts long-term health status. The objectives of this study were to characterize the effects of low dose gamma-radiation on lipids and antioxidants by monitoring oxidation and reducing power, respectively, in model systems. Select oils and antioxidants were exposed to levels of gamma-radiation ranging from 0 to 1000 Gy (1 Gy = 1 Sv) using a Gammacell 220 and stored at ambient or elevated temperatures (65 C) for up to 3 months prior to analysis. A Fricke dosimeter was used to verify differences between the radiation doses administered. Primary and secondary products of lipid oxidation in soybean and peanut oils were monitored using conjugated diene and 2-thiobarbituric acid (TBARs) assays. Changes in fatty acid composition and formation and vitamin E levels were also measured. The reducing power of antioxidant compounds, including vitamins C and E and beta-carotene, was determined using the ferric reducing antioxidant power (FRAP) assay. Significant differences (alpha =0.05) were present between all radiation doses tested using the Fricke dosimeter. Increasing radiation doses above 3 Sv resulted in significantly (alpha =0.05) elevated levels of oxidation and free fatty acids in soybean and peanut oils. Decreases in concentrations of essential fatty acids upon increasing radiation doses were also observed. Increasing radiation doses caused significant (alpha =0.05) decreases in reducing power and hence the effectiveness of vitamins C and E as well as beta-carotene. This work establishes a need for quantifying the effects of space relevant radiation doses in the development of a food system for an extended duration mission and for identifying threshold radiation levels that will impact the useful shelf-life of the variety of foods that will be sent. Eventual rancidity of lipids and the loss of antioxidant bioprotective effects are major concerns for the acceptability and nutritional profile of a food system.

Gandolph, Jacob; Mauer, Lisa; Perchonok, Michele

2006-01-01

48

Terrestrial gamma radiation dose study to determine the baseline for environmental radiological health practices in Melaka state, Malaysia  

Microsoft Academic Search

Environmental terrestrial gamma radiation dose rates were measured throughout Melaka, Malaysia, over a period of two years, with the objective of establishing baseline data on the background radiation level. Results obtained are shown in tabular, graphic and cartographic form. The values of terrestrial gamma radiation dose rate vary significantly over different soil types and for different underlying geological characteristics present

Ahmad Termizi Ramli; Sallehudin Sahrone; Husin Wagiran

2005-01-01

49

Fast Neutron Generators: Radiation Levels and Shielding Requirements  

Microsoft Academic Search

Neutron and gamma radiation levels around a Cockcroft-Walton neutron generator producing I4-Mev neutrons at an approximate rate of 10 neutrons per second were measured under conditions typical of those required for activation analysis. Neutron flux reduction to acceptable levels for limited operation was accomplished by 12 feet of distance that included shielding consisting of 27 inches of water and 16

R. J. Cloutier

1963-01-01

50

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

51

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

52

Satellite observation of atmospheric nuclear gamma radiation.  

PubMed

We present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3 1/2 years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features to be identified. The features are superimposed on a continuum background which is modeled using a power law with index -1.16. Many of these features contain a blend of more than one nuclear line. All of these lines (with the exception of the 511-keV annihilation line) are Doppler broadened. Line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric 14N and 16O. Although we find no evidence for other production mechanisms, we cannot rule out significant contributions from direct excitation or spallation by primary cosmic ray protons. The relative intensities of the observed line features are in fair agreement with theoretical models; however, existing models are limited by the availability of neutron cross sections, especially at high energies. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, can be explained by Compton scattering of the annihilation line photons in traversing an average of approximately 21 g cm-2 of atmosphere. PMID:11537397

Letaw, J R; Share, G H; Kinzer, R L; Silberberg, R; Chupp, E L; Forrest, D J; Rieger, E

1989-02-01

53

{gamma} decays of proton unbound levels in {sup 37}K  

SciTech Connect

Large discrepancies have been reported between the Gamow-Teller strengths determined from {sup 37}Ca {beta}-delayed proton decay, and the isospin-analog strengths deduced from {sup 37}Cl({ital p},{ital n}) studies. Some of these discrepancies could be removed if the {sup 37}Ca daughter level at 3.24 MeV in {sup 37}K had {Gamma}{sub {gamma}} forty times bigger than its {Gamma}{sub {ital p}}, and not negligibly small as assumed in the initial analysis of the {sup 37}Ca {beta} decay. We studied proton and {gamma}-ray branching ratios of low-lying {sup 37}K levels populated via the {sup 40}Ca({ital p},{alpha}) reaction. We find that the 3.24 MeV level has {Gamma}{sub {gamma}}/{Gamma}{sub {ital p}}{gt}8, and that the 2.75 and 3.08 MeV levels have {Gamma}{sub {gamma}}/{Gamma}{sub {ital p}}=0.52{plus_minus}0.23 and {Gamma}{sub {gamma}}/{Gamma}{sub {ital p}}=0.41{plus_minus}0.014, respectively. In addition we identified new {sup 37}K levels at {ital E}{sub {ital x}}=3.272{plus_minus}0.002 and 2.967{plus_minus}0.002 MeV.

Magnus, P.V.; Adelberger, E.G.; Cabot, N. [Nuclear Physics Laboratory GL-10, University of Washington, Seattle, Washington 98195 (United States)] [Nuclear Physics Laboratory GL-10, University of Washington, Seattle, Washington 98195 (United States)

1995-05-01

54

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

55

Pulsar and diffuse contributions to the observed galactic gamma radiation  

SciTech Connect

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.

1980-10-01

56

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

57

Gamma radiation effects in Yb-doped optical fiber  

NASA Astrophysics Data System (ADS)

Determination of the radiation response of doped-fiber laser materials, systems and components to relevant ionizing radiation fluxes is central to the prediction of long-term fiber-based laser performance/survivability in adverse and/or space-based environments. It is well known that optical elements that are placed into orbit around the Earth experience harsh radiation environments that originate from trapped-particle belts, cosmic rays, and solar events. Of particular interest to optical materials is the continuous flux of gamma photons that the materials encounter. Such radiation exposure commonly leads to the formation of color centers in a broad range of optical materials. Such color center formation gives rise to changes in optical transmission, loss and luminescent band structure, and, thus, impacts long-term optical device performance. In this paper we will present the results of our investigation of gamma-radiation-induced photodarkening on the passive optical transmittance of a number of ytterbium- (Yb-) doped optical fibers. We will discuss the evolution of the optical response of the fiber across the 1.0 to 1.6 micron wavelength window with increasing gamma exposure. Results indicate that these fibers exhibit reasonable radiation resistance to gamma exposures typical of a 5-year, low-earth-orbit environment. Maximum transmittance losses of less than 10% were observed for total gamma exposures of 2-5 krad (Si). In this paper we will present the results of our investigation of gamma-radiation-induced photodarkening on the optical transmittance of a number of ytterbium- (Yb-) doped optical fibers. We will discuss the evolution of the optical response of the fiber across the 1.0 to 1.6 micron wavelength window with increasing gamma exposure. Results indicate that these fibers exhibit reasonable radiation resistance to gamma exposures typical of a 5-year, low-earth orbit environment. Maximum transmittance losses of less than 10% were observed for total gamma exposures of 2-5 krad (Si).

Fox, B. P.; Schneider, Z. V.; Simmons-Potter, K.; Thomes, W. J., Jr.; Meister, D. C.; Bambha, R. P.; Kliner, D. A. V.; Söderlund, M. J.

2007-02-01

58

Comparison of the effects of gamma radiation on hydrated and air dried rye grass seeds  

SciTech Connect

This is a comparative study of the effects of gamma radiation on the growth of hydrated and air dried seeds during the first weeks of primary growth. Four groups of seeds were used in the study: 1) hydrated sweet corn, 2) air dried sweet corn, 3) hydrated rye grass, and 4) air dried rye grass. Each group was then further subdivided and exposed to various levels of gamma radiation using a Cobalt-60 irradiator, except for the control samples of the four groups which received no radiation above background level. All seeds samples were then planted, allowed to grow for approximately 12 days, and harvested. Growth of both shoot and root of each seed was recorded for data analysis according to specific groups. Analyses of data from this study shows that the mean growth of air dried seeds when exposed to gamma radiation prior to planting.

Worthington, M.

1988-01-01

59

Electret gamma X-ray low level dosimeter  

SciTech Connect

This patent describes an apparatus for monitoring gamma or X-ray radiation. It comprises a chamber having an inner surface which is electrically conductive, an electret positioned within the chamber for holding an electrostatic charge which collects ions formed in the chamber by bombardment of gamma or X-ray radiation, and a removable means connected with the chamber for mounting the electret, the chamber enclosed in a radioactive gas tight container.

Dempsey, J.C.

1991-04-16

60

Inactivation of rabies diagnostic reagents by gamma radiation  

SciTech Connect

Treatment of CVS-11 rabies adsorbing suspensions and street rabies infected mouse brains with gamma radiation resulted in inactivated reagents that are safer to distribute and use. These irradiated reagents were as sensitive and reactive as the nonirradiated control reagents.

Gamble, W.C.; Chappell, W.A.; George, E.H.

1980-11-01

61

Biological wound dressings sterilized with gamma radiation: Mexican clinical experience  

Microsoft Academic Search

Biological wound dressings sterilized with gamma radiation, such as amnion and pig skin, are a reality in Mexico. These tissues are currently processed in the tissue bank and sterilized in the Gamma Industrial Irradiation Plant; both facilities belong to the Instituto Nacional de Investigaciones Nucleares (ININ) (National Institute of Nuclear Research). With the strong support of the International Atomic Energy

M. E. Martínez-Pardo; E. Ley-Chávez; M. L. Reyes-Frías; P. Rodríguez-Ferreyra; L. Vázquez-Maya; M. A. Salazar

2007-01-01

62

Gamma Radiation from Co56 and Co58  

Microsoft Academic Search

The gamma rays following the decay of Co56 and Co58 have been observed by means of a large NaI(Tl) crystal scintillation spectrometer. Relative intensities of the Co56 gamma radiation are presented as well as ratios of orbital electron capture to positron emission for both Co56 and Co58.

C. Sharp Cook; F. M. Tomnovec

1956-01-01

63

An investigation of gamma background radiation in Hamadan province, Iran.  

PubMed

The general population, everywhere in the world is exposed to a small dose of ionising radiation from natural sources. Stochastic effects such as cancer and genetic disorders are caused when living creatures are exposed to low doses. In Iran, it is measured in some cities, especially in high-background areas such as Ramsar, but so far there is no measurement in the Hamadan province. Hamadan is located in the west of Iran. Measurements were performed using a RDS-110 survey meter, CaSO(4):Dy thermoluminecense dosimetries (TLDs) and a Harshaw 4000 TLD reader. To estimate the dose rate  outdoors, four stations along the main directions (north, south, west and east) and one in the town centre were selected. Mean annual X and gamma equivalent dose in Hamadan province are 1.12±0.22  and 1.66±0.07 mSv, which related to RDS-110 survey meter and TLDs measurements, respectively. The TLDs and RDS-110 results are representative of the external photon radiation doses for the selected monitoring locations and for those locations for the hours during which the measurements were taken, respectively. Maximum and minimum of external photon radiation doses are related to Hamadan and Kaboudar-Ahang towns, respectively. According to the results of the study, it seems that the annual X and gamma equivalent dose in Hamadan province exceeded the global mean external exposure amounts by the UNSCEAR, and further studies are needed to measure internal exposures to determine the total environmental radiation level in  Hamadan province. PMID:22570508

Rostampour, Nima; Almasi, Tinoosh; Rostampour, Masoumeh; Mohammadi, Mohammad; Ghazikhanlou Sani, Karim; Khosravi, Hamid R; Pooya, S Mehdi Hosseini; Golzar, Bahman; Jabari Vesal, Naghi

2012-12-01

64

[Chlorophyll mutations induced by gamma radiation in Phaseolus vulgaris L].  

PubMed

In a study of chlorophyll mutants of Phaseolus vulgaris L. through Co60 gamma radiation, five types of mutants, classified as albino, cream, yellow, yellow-green and light green were obtained; all were lethal; their segregation was always proportionally lower than the Mendelian. Gamma radiation-induced mutations in black beans do not depart significantly from those obtained elsewhere in barley and wheat. PMID:1197814

Meoño, M E

1975-07-01

65

Predicted levels of human radiation tolerance extrapolated from clinical studies of radiation effects  

NASA Technical Reports Server (NTRS)

Results of clinical studies of radiation effects on man are used to evaluate space radiation hazards encountered during manned space travel. Considered are effects of photons as well as of mixed fission neutrons and gamma irradiations in establishing body radiosensitivity and tolerance levels. Upper and lower dose-response-time relations for acute radiation syndromes in patients indicate that man is more than sufficiently radioresistant to make the risks of an early radiation effect during one short space mission intangibly small in relation to the other nonradiation risks involved.

Lushbaugh, C. C.

1972-01-01

66

Distinguishing Neutrons and Gammas with MSL's Radiation Assessment Detector (RAD)  

NASA Astrophysics Data System (ADS)

The radiation environment on the Martian surface is a complex mixture of charged primary and secondary radiation and of neutral secondary radiation. This neutral component amounts to a significant fraction of the surface radiation field and consists of neutrons and gamma rays. The neutron component is especially important from a radiation protection point of view, but is experimentally difficult to distinguish from the gamma rays. The Radiation Assessment Detector (RAD) on Mars Science Laboratory's (MSL's) rover Curiosity measures both neutrons and gammas. It consists of a compact arrangement of a dense, more gamma-sensitive CsI sctintillator, and a high-proton-content plastic scintillator, which in turn is more sensitive to neutrons. Using sophisticated inversion techniques, the RAD measurements can be inverted to provide reliable estimates for the neutron and gamma spectra on Mars. In this work we will discuss the status of the inversion techniques and calibration data, and relate them with predictions for the neutral component of the Martian surface radiation field.

Guo, J.; Hassler, D.; Wimmer-Schweingruber, R. F.; Zeitlin, C.; Boettcher, S.; Martin, C.; Brinza, D.; Koehler, J.; Böhm, E.; Kharytonov, A.; Ehresmann, B.

2012-12-01

67

Breeding biology of Tree Swallows and House Wrens in a gradient of gamma radiation  

Microsoft Academic Search

In a gradient of gamma radiation from 38.7 mC kg⁻¹.d⁻¹ to background levels of 0.05 ..mu..C. kg⁻¹ . d⁻¹ to background levels of 0.05 ..mu..C . kg⁻¹ . d⁻¹, Tree Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) avoided nesting in areas of high radiation. Nest boxes selected by swallows and wrens had a mean exposure rate of only 9.3

R. Zach; K. R. Mayoh

1982-01-01

68

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

E-print Network

)levels of 485 R, 715 R, and 894 R have been determined for green- winged teal (Anas crecca),blue-winged teal (Anas discors), and shovelers (Anas cly- peata) (1). The other study on waterfowl reports LDSO(O0)levels for one-year-old mallards(Anas platyrhynchos)of 650 R for x-radiation and 630 R for 60-Co, Gamma radiation

Minnesota, University of

69

Gamma and proton radiation effects in erbium-doped fiber amplifiers: active and passive measurements  

Microsoft Academic Search

Commercially available Er-doped fibers were irradiated with 5.6 and 28 MeV protons and 60Co gamma rays, up to levels of 50 krad. White-light transmission spectra under passive conditions (no pump or signal) were measured at several radiation levels for the six types of fibers that were tested. The spectra were used to evaluate the relative radiation sensitivity of the fibers

Todd S. Rose; Deana Gunn; George C. Valley

2001-01-01

70

Low level radiation: biological effects  

Microsoft Academic Search

It is imperative that physicians and scientists using radiations in health care delivery continue to assess the benefits derived, vs. potential risk, to patients and radiation workers being exposed to radiation in its various forms as part of our health delivery system. Insofar as possible we should assure our patients and ourselves that the benefits outweigh the potential hazards involved.

Loken

1983-01-01

71

Some Radiation Techniques Used in the GU-3 Gamma Irradiator  

SciTech Connect

Different radiation techniques, measurement of dose and its distibution throughout the irradiated materials are the main problems treated in this paper. The oscillometry method combined with the ionization chamber, as an absolute dosimeter, is used for calibration of routine ECB dosimeters. The dose uniformity, for the used radiation techniques in our GU-3 Gamma Irradiator with Cs-137, is from 93% up to 99%.

Dodbiba, Andon [Institute of Nuclear Physics, P.O. Box 85, Tirana (Albania); Ylli, Ariana; Stamo, Iliriana; Kongjika, Efigjeni [Institute of Biological Research, Rruga Sami Frasheri 5, Tirana (Albania)

2007-04-23

72

Observations of Galactic gamma-radiation with the SMM spectrometer  

NASA Technical Reports Server (NTRS)

Preliminary results from the SMM gamma-ray spectrometer are reported which indicate the detection of a constant source of 0.511-MeV annihilation radiation from the Galaxy. Year-to-year variability appears to be less than 30 percent. The radiation probably comes from a diffuse source and is not associated with the reported compact object at the Galactic center.

Share, G. H.; Kinzer, R. L.; Messina, D. C.; Purcell, W. R.; Chupp, E. L.

1986-01-01

73

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

74

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

75

Effects of low-level radiation  

Microsoft Academic Search

The effects of low-level radiation inhumans are usually estimated by extrapolation from high-level effects. Biological radiation effects from low-level radiation can be defined as those from doses below which no deterministic or graded biological responses will occur. In addition, the health consequences are almost all probabilistic. There is incomplete knowledge regarding the role of sex, age at exposure, co-factors, or

Goldman

1993-01-01

76

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

77

A study of the diffuse galactic gamma radiation  

NASA Technical Reports Server (NTRS)

Assuming cosmic rays pervade the Galaxy, they necessarily produced high energy gamma-rays as they interact with the instellar matter and photons. The cosmic ray nucleon interactions five rise to gamma rays primarily through the decay of pi mesons, giving a unique spectrum with a maximum at approximately 68 MeV. Cosmic ray electrons produce gamma rays through bremsstrahlung, but with a markedly different energy spectral shape, one which decreases monotonically with energy. Cosmic ray electrons also interact with the interstellar starlight, optical and infrared photons, and the blackbody radiation through the Compton process. A model of galactic gamma ray production is discussed, and the predicted spatial distribution and energy spectra are presented. Considering the uncertainty in the point source contributions, the agreement between the theoretical predictions and the gamma ray data seems quite reasonable.

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

1982-01-01

78

Monitoring precipitation and lightning via changes in atmospheric gamma radiation  

SciTech Connect

Atmospheric {gamma}-radiation has been measured since 1999 and recently at three elevations 220m from the first site to ascertain position dependency and optimal elevation for observing {gamma}-rays from radon and radon-progeny found in precipitation. Radiation from time-independent and diurnal components was minimized in order to ascertain the reliability, accuracy and practicality of determining precipitation rates from correlated {gamma}-rates. Data taken with 4-12.9cm3 NaI detectors at elevations above ground of 9.91, 14.2, 15.7, and 21.4 m were fit with a model assuming a surface and/or volume deposition of radon progeny on/in water droplets during precipitation which predicts {gamma} -ray rates proportional to the 2/5 and/or 3/5 power of rain rates, respectively. With mostly surface deposition and age corrections for radon progeny, the correlation coefficients improved with elevation and reached a maximum at 0.95 around 20m. Atmospheric {gamma} radiation enables monitoring precipitation rates to 0.3 mm/h with time resolution limited only by counting statistics. High {gamma}-ray rates, decreasing with 40-minute half-life following lightning may be indirectly due to ions accelerated in electric field.

Greenfield, M.B.; Domondon, A.; Tsuchiya, S.; Tomiyama, G. [International Christian University, Mitaka (Japan)

2003-08-26

79

Impact of spectral smoothing on gamma radiation portal alarm probabilities.  

PubMed

Gamma detector counts are included in radiation portal monitors (RPM) to screen for illicit nuclear material. Gamma counts are sometimes smoothed to reduce variance in the estimated underlying true mean count rate, which is the "signal" in our context. Smoothing reduces total error variance in the estimated signal if the bias that smoothing introduces is more than offset by the variance reduction. An empirical RPM study for vehicle screening applications is presented for unsmoothed and smoothed gamma counts in low-resolution plastic scintillator detectors and in medium-resolution NaI detectors. PMID:21612936

Burr, T; Hamada, M; Hengartner, N

2011-10-01

80

Gamma line radiation from supernovae. [nucleosynthesis  

NASA Technical Reports Server (NTRS)

Recent calculations of core collapse or massive stars result in explosive ejection of the mantle by a reflected shock. These hydrodynamic results are important for predictions of explosive nucleosynthesis and gamma-ray line emission from supernovae. Previous estimates, based on simple parameterized models or the nucleosynthesis in an average supernova, are compared with these latest results.

Arnett, W. D.

1978-01-01

81

Dosimetric studies for gamma radiation validation of medical devices.  

PubMed

The delivery and validation of a specified dose to medical devices are key concerns to operators of gamma radiation facilities. The objective of the present study was to characterize the industrial gamma radiation facility and map the dose distribution inside the product-loading pattern during the validation and routine control of the sterilization process using radiochromic films. Cardboard phantoms were designed to achieve the homogeneity of absorbed doses. The uncertainty of the dose delivered during validation of the sterilization process was assessed. PMID:23079487

Soliman, Y S; Beshir, W B; Abdel-Fattah, A A; Abdel-Rehim, F

2013-01-01

82

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

83

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

84

Chain decomposition of aqueous triethanolamine. [Gamma Radiation  

Microsoft Academic Search

A radiation-induced chain decomposition of aqueous triethanolamine into acetaldehyde and diethanolamine is reported. Chain lengths over 1000 have been observed, depending on pH, concentration, and radiation intensity. The chain propagation steps include OH group migration in the 2-hydroxy-1-(diethanolamino)ethyl radical and NRâ migration in 1-hydroxy-2(diethanolamine)ethyl radical, each producing a 2-hydroxy-2-(diethanolamine)ethyl radical. Free-radical spectra and rate constants are given. Studies of diethanolamine

1982-01-01

85

Search for the radiative transitions $\\psi(3770)\\to\\gamma\\eta_c$ and $\\gamma\\eta_c(2S)$  

E-print Network

By using a 2.92 fb$^{-1}$ data sample taken at $\\sqrt{s} = 3.773$ GeV with the BESIII detector operating at the BEPCII collider, we search for the radiative transitions $\\psi(3770)\\to\\gamma\\eta_c$ and $\\gamma\\eta_c(2S)$ through the hadronic decays $\\eta_c(\\eta_c(2S))\\to K^0_SK^\\pm\\pi^\\mp$. No significant excess of signal events above background is observed. We set upper limits at a 90% confidence level for the product branching fractions to be $\\mathcal{B}(\\psi(3770)\\to\\gamma\\eta_c)\\times \\mathcal{B}(\\eta_c\\to K^0_SK^\\pm\\pi^\\mp) world-average values of $\\mathcal{B}(\\eta_c(\\eta_c(2S))\\to K^0_SK^\\pm\\pi^\\mp)$, we find the branching fractions $\\mathcal{B}(\\psi(3770)\\to\\gamma\\eta_c) < 6.8\\times10^{-4}$ and $\\mathcal{B}(\\psi(3770)\\to\\gamma\\eta_c(2S)) < 2.0\\times10^{-3}$ at a 90% confidence level.

Ablikim, M; Ai, X C; Albayrak, O; Albrecht, M; Ambrose, D J; An, F F; An, Q; Bai, J Z; Ferroli, R Baldini; Ban, Y; Bennett, D W; Bennett, J V; Bertani, M; Bian, J M; Boger, E; Bondarenko, O; Boyko, I; Braun, S; Briere, R A; Cai, H; Cai, X; Cakir, O; Calcaterra, A; Cao, G F; Cetin, S A; Chang, J F; Chelkov, G; Chen, G; Chen, H S; Chen, J C; Chen, M L; Chen, S J; Chen, X; Chen, X R; Chen, Y B; Cheng, H P; Chu, X K; Chu, Y P; Cronin-Hennessy, D; Dai, H L; Dai, J P; Dedovich, D; Deng, Z Y; Denig, A; Denysenko, I; Destefanis, M; Ding, W M; Ding, Y; Dong, C; Dong, J; Dong, L Y; Dong, M Y; Du, S X; Fan, J Z; Fang, J; Fang, S S; Fang, Y; Fava, L; Feng, C Q; Fu, C D; Fuks, O; Gao, Q; Gao, Y; Geng, C; Goetzen, K; Gong, W X; Gradl, W; Greco, M; Gu, M H; Gu, Y T; Guan, Y H; Guo, L B; Guo, T; Guo, Y P; Haddadi, Z; Han, S; Han, Y L; Harris, F A; He, K L; He, M; He, Z Y; Held, T; Heng, Y K; Hou, Z L; Hu, C; Hu, H M; Hu, J F; Hu, T; Huang, G M; Huang, G S; Huang, H P; Huang, J S; Huang, L; Huang, X T; Huang, Y; Hussain, T; Ji, C S; Ji, Q; Ji, Q P; Ji, X B; Ji, X L; Jiang, L L; Jiang, L W; Jiang, X S; Jiao, J B; Jiao, Z; Jin, D P; Jin, S; Johansson, T; Julin, A; Kalantar-Nayestanaki, N; Kang, X L; Kang, X S; Kavatsyuk, M; Kloss, B; Kopf, B; Kornicer, M; Kuehn, W; Kupsc, A; Lai, W; Lange, J S; Lara, M; Larin, P; Leyhe, M; Li, C H; Li, Cheng; Li, Cui; Li, D; Li, D M; Li, F; Li, G; Li, H B; Li, J C; Li, Jin; Li, K; Li, K; Li, P R; Li, Q J; Li, T; Li, W D; Li, W G; Li, X L; Li, X N; Li, X Q; Li, Z B; Liang, H; Liang, Y F; Liang, Y T; Lin, D X; Liu, B J; Liu, C L; Liu, C X; Liu, F H; Liu, Fang; Liu, Feng; Liu, H B; Liu, H H; Liu, H M; Liu, J; Liu, J P; Liu, K; Liu, K Y; Liu, P L; Liu, Q; Liu, S B; Liu, X; Liu, Y B; Liu, Z A; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H; Lou, X C; Lu, G R; Lu, H J; Lu, H L; Lu, J G; Lu, Y; Lu, Y P; Luo, C L; Luo, M X; Luo, T; Luo, X L; Lv, M; Lyu, X R; Ma, F C; Ma, H L; Ma, Q M; Ma, S; Ma, T; Ma, X Y; Maas, F E; Maggiora, M; Malik, Q A; Mao, Y J; Mao, Z P; Messchendorp, J G; Min, J; Min, T J; Mitchell, R E; Mo, X H; Mo, Y J; Moeini, H; Morales, C Morales; Moriya, K; Muchnoi, N Yu; Muramatsu, H; Nefedov, Y; Nerling, F; Nikolaev, I B; Ning, Z; Nisar, S; Niu, X Y; Olsen, S L; Ouyang, Q; Pacetti, S; Pelizaeus, M; Peng, H P; Peters, K; Ping, J L; Ping, R G; Poling, R; Qi, M; Qian, S; Qiao, C F; Qin, L Q; Qin, N; Qin, X S; Qin, Y; Qin, Z H; Qiu, J F; Rashid, K H; Redmer, C F; Ripka, M; Rong, G; Ruan, X D; Sarantsev, A; Schoenning, K; Schumann, S; Shan, W; Shao, M; Shen, C P; Shen, X Y; Sheng, H Y; Shepherd, M R; Song, W M; Song, X Y; Spataro, S; Spruck, B; Sun, G X; Sun, J F; Sun, S S; Sun, Y J; Sun, Y Z; Sun, Z J; Sun, Z T; Tang, C J; Tang, X; Tapan, I; Thorndike, E H; Tiemens, M; Toth, D; Ullrich, M; Uman, I; Varner, G S; Wang, B; Wang, D; Wang, D Y; Wang, K; Wang, L L; Wang, L S; Wang, M; Wang, P; Wang, P L; Wang, Q J; Wang, S G; Wang, W; Wang, X F; Wang, Y D; Wang, Y F; Wang, Y Q; Wang, Z; Wang, Z G; Wang, Z H; Wang, Z Y; Wei, D H; Wei, J B; Weidenkaff, P; Wen, S P; Werner, M; Wiedner, U; Wolke, M; Wu, L H; Wu, N; Wu, Z; Xia, L G; Xia, Y; Xiao, D; Xiao, Z J; Xie, Y G; Xiu, Q L; Xu, G F; Xu, L; Xu, Q J; Xu, Q N; Xu, X P; Xue, Z; Yan, L; Yan, W B; Yan, W C; Yan, Y H; Yang, H X; Yang, L; Yang, Y; Yang, Y X; Ye, H; Ye, M; Ye, M H; Yu, B X; Yu, C X; Yu, H W; Yu, J S; Yu, S P; Yuan, C Z; Yuan, W L; Yuan, Y; Yuncu, A; Zafar, A A; Zallo, A; Zang, S L; Zeng, Y; Zhang, B X; Zhang, B Y; Zhang, C; Zhang, C B; Zhang, C C; Zhang, D H; Zhang, H H; Zhang, H Y; Zhang, J J; Zhang, J Q; Zhang, J W; Zhang, J Y; Zhang, J Z; Zhang, S H; Zhang, X J; Zhang, X Y; Zhang, Y; Zhang, Y H; Zhang, Z H; Zhang, Z P; Zhang, Z Y; Zhao, G; Zhao, J W; Zhao, Lei; Zhao, Ling; Zhao, M G; Zhao, Q; Zhao, Q W; Zhao, S J; Zhao, T C; Zhao, X H; Zhao, Y B; Zhao, Z G; Zhemchugov, A; Zheng, B; Zheng, J P; Zheng, Y H; Zhong, B; Zhou, L; Zhou, Li; Zhou, X; Zhou, X K; Zhou, X R; Zhou, X Y; Zhu, K; Zhu, K J; Zhu, X L; Zhu, Y C; Zhu, Y S; Zhu, Z A; Zhuang, J; Zou, B S; Zou, J H

2014-01-01

86

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

87

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

88

Chain decomposition of aqueous triethanolamine. [Gamma Radiation  

SciTech Connect

A radiation-induced chain decomposition of aqueous triethanolamine into acetaldehyde and diethanolamine is reported. Chain lengths over 1000 have been observed, depending on pH, concentration, and radiation intensity. The chain propagation steps include OH group migration in the 2-hydroxy-1-(diethanolamino)ethyl radical and NR/sub 2/ migration in 1-hydroxy-2(diethanolamine)ethyl radical, each producing a 2-hydroxy-2-(diethanolamine)ethyl radical. Free-radical spectra and rate constants are given. Studies of diethanolamine and diethylethanolamine solutions gave similar free-radical spectra but much shorter chains.

Schwarz, H.A.

1982-08-19

89

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

90

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

PubMed Central

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

91

Bioburden assessment and gamma radiation inactivation patterns in parchment documents  

NASA Astrophysics Data System (ADS)

Parchment documents are part of our cultural heritage and, as historical artifacts that they are, should be preserved. The aim of this study was to validate an appropriate methodology to characterize the bioburden of parchment documents, and to assess the growth and gamma radiation inactivation patterns of the microbiota present in that material. Another goal was to estimate the minimum gamma radiation dose (Dmin) to be applied for the decontamination of parchment as an alternative treatment to the current toxic chemical and non-chemical decontamination methods. Two bioburden assessment methodologies were evaluated: the Swab Method (SM) and the Destructive Method (DM). The recovery efficiency of each method was estimated by artificial contamination, using a Cladosporium cladosporioides spore suspension. The parchment samples' microbiota was typified using morphological methods and the fungal isolates were identified by ITS-DNA sequencing. The inactivation pattern was assessed using the DM after exposure to different gamma radiation doses, and using C. cladosporioides as reference. Based on the applied methodology, parchment samples presented bioburden values lower than 5×103 CFU/cm2 for total microbiota, and lower than 10 CFU/cm2 for fungal propagules. The results suggest no evident inactivation trend for the natural parchment microbiota, especially regarding the fungal community. A minimum gamma radiation dose (Dmin) of 5 kGy is proposed for the decontamination treatment of parchment. Determining the minimal decontamination dose in parchment is essential for a correct application of gamma radiation as an alternative decontamination treatment for this type of documents avoiding the toxicity and the degradation promoted by the traditional chemical and non-chemical treatments.

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

2013-07-01

92

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

93

THERMAL RADIATION FROM GAMMA-RAY BURST JETS  

SciTech Connect

In this study, the light curves and spectrum of the photospheric thermal radiation from ultrarelativistic gamma-ray burst (GRB) jets are calculated using two-dimensional relativistic hydrodynamic simulations of jets from a collapsar. As the jet advances, the density around the head of the jet decreases, and its Lorentz factor reaches as high as 200 at the photosphere and 400 inside the photosphere. For an on-axis observer, the photosphere appears concave due to the low density and high beaming factor of the jet. The luminosity varies because of the abrupt change in the position of the photosphere due to the internal structure of the jet. Comparing our results with GRB 090902B, the flux level of the thermal-like component is similar to our model, although the peak energy appears slightly higher (but still within a factor of two). From the comparison, we estimate that the bulk Lorentz factor of GRB 090902B is {Gamma} {approx} 2.4 x 10{sup 2}(r/10{sup 12} cm), where r is the radius of the photosphere. The spectrum for an on-axis observer is harder than that for an off-axis observer. There is a time lag of a few seconds for high energy bands in the light curve. This may be the reason for the delayed onset of GeV emission seen in GRB 080916C. The spectrum below the peak energy is a power law and the index is 2.3-2.6, which is softer than that of a single temperature Planck distribution but still harder than that of the typical value of the observed spectrum.

Mizuta, Akira [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Nagataki, Shigehiro; Aoi, Junichi, E-mail: mizuta@post.kek.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

2011-05-01

94

Gamma-ray decay of levels in /sup 53/Cr  

SciTech Connect

Gamma-ray decay of levels in the stable isotope /sup 53/Cr has been studied using /sup 53/Cr(n,n'..gamma..) reactions for incident neutron energies between threshold and 10 MeV. Of the 65 gamma rays or gamma-ray groups observed for neutron interactions with /sup 53/Cr, 50 have been placed or tentatively placed among 34 levels in /sup 53/Cr up to an excitation energy of 4.36 MeV. Deduced branching ratios are in reasonable agreement with previous measurements except for decay of the E/sub x/ = 1537-keV level. For the decay of the E/sub x/ = 1537-keV level we are unable to explain variations in the branching ratios of the transition gamma rays as a function of incident neutron energy within the framework of the presently known level structure of /sup 53/Cr and suggest the possibility of a second energy level at E/sub x/ = 1537 keV. 59 refs., 13 figs., 2 tabs.

Dickens, J.K.; Larson, D.C.

1987-11-01

95

Observations of diffuse galactic gamma radiation  

SciTech Connect

A new window for studying our Galaxy has emerged after over two decases of concerted effort with satellite and balloon-borne gammay-ray experiments. These experiments have discovered what appears to be a diffuse glow along the Galactic plane in lines at 0.511 and 1.809 MeV. I summarize these observations, with emphasis on measurements made with the Gamma-Ray Spectrometer (GRS) on NASA's Solar Maximum Mission satellite (SMM). The GRS is currently being used to study other diffuse Galactic emissions including the positronium continuum, radioactive lines from recent supernovae and novae, and de-excitation lines from interactions of cosmic-ray protons with interstellar carbon and oxygen.

Share, G.H.

1988-09-25

96

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

97

Thermal analysis evaluation of mechanical properties changes promoted by gamma radiation on surgical polymeric textiles  

NASA Astrophysics Data System (ADS)

The large number of surgical operations with post-operative infection problems and the appearing of new infectious diseases, contribute to the development of new materials in order to answer the needs of health care services. This development must take into account the modifications promoted by sterilisation methods in materials, namely by gamma radiation. The differential scanning calorimetry (DSC) and thermogravimetry (TGA) techniques show that a nonwoven and a laminate textiles maintain a good molecular cohesion, do not showing high levels of degradation, for gamma radiation dose values lower than 100 kGy in nonwoven and 200 kGy in laminate materials. The tensile strength and the elongation decrease slowly for the nonwoven textile and decrease faster for the laminate textile for 25 and 80 kGy absorbed dose. This paper shows that the DSC and TGA techniques can be helpful for the prevision of mechanical changes occurred in the materials as a consequence of the gamma irradiation.

Ferreira, L. M.; Casimiro, M. H.; Oliveira, C.; Cabeço Silva, M. E.; Marques Abreu, M. J.; Coelho, A.

2002-05-01

98

Measurement of neutron and gamma radiation in a mixed field.  

PubMed

This paper describes a study of dosimeters with a range of 0 to 0.2 mGy that were developed by the authors and built by the Federal Emergency Management Agency (FEMA). These instruments are a type of air-filled ion chamber that is self-reading by means of an internal carbon fiber electrometer. Two types of these dosimeters were constructed: one with an ion chamber wall made of a conductive hydrogenous material, and the other device made with a conductive wall lining of non-hydrogenous material. Both types of dosimeters have the same sensitivity for gamma radiation, but greatly different sensitivities for fast neutrons, thus making it possible to measure gamma radiation and neutron doses separately in a mixed radiation field. The results indicate that such pairs of dosimeters can be used for the first time to accurately monitor personnel for gamma ray and neutron doses in real time. Since the difference in neutron sensitivities is due to the properties of wall materials, periodic calibrations of the dosimeter system can be accomplished using only gamma rays after the material constants are measured. The absolute number of neutron induced transmutations in sulfur was required for this work. Methods and techniques which were applied to determine this quantity are described in the text. This approach was one of several dosimetric procedures utilized in this investigation. PMID:7558835

Kronenberg, S; Bechtel, E; Brucker, G J

1995-10-01

99

Comparative response of selected thermoluminescence materials in a mixed-gamma and -neutron radiation environment  

SciTech Connect

Six materials ({sup nat}LiF:Mg,Ti; {sup 6}LiF:Mg,Ti; {sup 7}LiF:Mg,Ti; CaF{sub 2}:Mn; CaSO{sub 4}:Mn; and CaSO{sub 4}:Dy) were evaluated for thermoluminescence (TL) response in a mixed gamma and neutron radiation environment by irradiating the materials to various levels of 1-MeV equivalent neutron fluence. In order to assess the suitability of the materials as reliable indicators of gamma absorbed dose in the mixed radiation field, response characteristics were compared with the response of identical TL dosimeters calibrated by irradiation in a NIST-traceable {sup 137}Cs gamma field. Fading, glow curve shape, and integrated response from the TL materials irradiated in the mixed and pure gamma radiation environments are compared and discussed. CaF{sub 2}:Mn was found to be a superior material for gamma dosimetry in the mixed-field environment due to neutron insensitivity, excellent linearity in the dosimeter response with 1-MeV fluence, low fading characteristics, and independence of the TL response with isotopic purity of the phosphor.

Bennion, J.S.; Sandquist, G.M.; Hardy, B.L. [Univ. of Utah, Salt Lake City, UT (United States); Rogers, V.C. [Rogers & Associates Eng. Corp., Salt Lake City, UT (United States); Terry, B.W. [Teledyne Isotopes, Westwood, NJ (United States)

1994-12-31

100

Gamma radiation survey of the LDEF spacecraft  

NASA Technical Reports Server (NTRS)

The retrieval of the Long Duration Exposure Facility spacecraft in January 1990 after nearly six years in orbit offered a unique opportunity to study the long term buildup of induced radioactivity in the variety of materials on board. We conducted the first complete gamma-ray survey of a large spacecraft on LDEF shortly after its return to earth. A surprising observation was the 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 observed during the survey, the strongest being Na-22, are all attributed to activation of spacecraft components. 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.

1992-01-01

101

Effects of gamma radiation on snake venoms  

NASA Astrophysics Data System (ADS)

Ionizing radiation is able to detoxify several venoms, including snake venoms, without affecting significantly their immunogenic properties. Inn order to elucidate this phenomena, we conceived a comparative pharmacological study between native and irradiated (2,000 Gy) crotoxin, the main toxin of the South American rattlesnake Crotalus durissus terrificus. Crotoxin was isolated and purified by molecular exclusion chromatography, pI precipitation and, susbequentely submitted to irradiaiton. Gel filtration of the irradiated toxin resulted in some high molecular weight aggregates formation. Crotoxin toxicity decreased two folds after irradiation, as determined by LD 50 in mice. Native and irradiated crotoxin biodistribution ocured in the same general manner, with renal elimination. However, in contrast to irradiated crotoxin, the native form was initially retained in kidneys. A later concentration (2-3 hr) appeared in phagocytic mononuclear cells rich organs (liver and spleen) and neural junction rich organs (muscle and brain).

Nascimento, N.; Spencer, P. J.; Andrade, H. F.; Guarnieri, M. C.; Rogero, J. R.

1998-06-01

102

Oxidation of naringenin by gamma-radiation  

NASA Astrophysics Data System (ADS)

The reaction of rad OH with naringenin (4',5,7-trihydroxyflavanone) in the presence of air induced the formation of the hydroxylation product eriodictyol (3',4',5,7-tetrahydroxyflavanone). Its yield was dependent on pH. The initial degradation yield of naringenin was Gi(-Nar)=(2.5±0.2)×10 -7 mol dm -3 J -1. For the reaction with rad OH, a rate constant k ( rad OH+naringenin)=(7.2±0.7)×10 9 M -1 s -1 was determined. In the presence of N 2O and NaN 3/N 2O, no eriodyctiol was formed. Apigenin (4',5,7-trihydroxyflavon) was detected as decay product of the naringenin phenoxyl radicals. In Ar-saturated solutions, naringenin exhibited a pronounced radiation resistance, G(-naringenin) ˜0.3×10 -7 mol dm -3 J -1.

Nagy, Tristan O.; Ledolter, Karin; Solar, Sonja

2008-06-01

103

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

104

Anomalous primary radiation from the Leksell Gamma Knife Unit  

SciTech Connect

The Leksell Gamma Knife Unit, Type U, utilizes 201 separate {sup 60}Co sources intersecting at a common focus for radiosurgical treatment of the brain. It has been generally understood that all primary unattenuated radiation beams are confined with the protective housing during all phases of Gamma Knife operations. The authors have found that when the unit`s shielding door is lowered for treatment, twelve primary beams exit the unit`s door opening. Furthermore, in the original Gamma Knife unit design, two of the twelve primary beams failed to be attenuated by either the unit base or the unit wings. This has implications for the design of structural shielding and the protection of personnel during emergency procedures. Engineering modifications to eliminate the problem are discussed. 1 ref., 2 figs.

Shearer, D.R. [Rhode Island Hospital, Providence, RI (United States); Roventine, W.A. [Radiation Physics Services, Harrisville, RI (United States); Coy, S.R. [Neural Science Center, Coral Gables, FL (United States)

1994-12-01

105

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

106

Titanium-Water Thermosyphon Gamma Radiation Effects and Results  

NASA Technical Reports Server (NTRS)

Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some exposure to gamma irradiation. Non-condensable gas formation from radiation may breakdown water over time and render a portion of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature with accelerated gamma irradiation exposures on the same order of magnitude that is expected in eight years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon; evaporator, condenser, and condenser end cap. Some non-condensable gas was evident, however thermosyphon performance was not affected because the non-condensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of non-condensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the non-condensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of selected thermosyphons at temperature and in a vacuum chamber revealed that the non-condensable gas likely diffused out of the thermosyphons over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

Sanzi, James L.; Jaworske, Donald A.; Goodenow, Debra A.

2012-01-01

107

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

108

Radon flux maps for the Netherlands and Europe using terrestrial gamma radiation derived from soil radionuclides  

NASA Astrophysics Data System (ADS)

Naturally occurring radioactive noble gas, radon (222Rn) is a valuable tracer to study atmospheric processes and to validate global chemical transport models. However, the use of radon as a proxy in atmospheric and climate research is limited by the uncertainties in the magnitude and distribution of the radon flux density over the Earth's surface. Terrestrial gamma radiation is a useful proxy for generating radon flux maps. A previously reported radon flux map of Europe used terrestrial gamma radiation extracted from automated radiation monitoring networks. This approach failed to account for the influence of local artificial radiation sources around the detector, leading to under/over estimation of the reported radon flux values at different locations. We present an alternative approach based on soil radionuclides which enables us to generate accurate radon flux maps with good confidence. Firstly, we present a detailed comparison between the terrestrial gamma radiation obtained from the National Radiation Monitoring network of the Netherlands and the terrestrial gamma radiation calculated from soil radionuclides. Extending further, we generated radon flux maps of the Netherlands and Europe using our proposed approach. The modelled flux values for the Netherlands agree reasonably well with the two observed direct radon flux measurements (within 2? level). On the European scale, we find that the observed radon flux values are higher than our modelled values and we introduce a correction factor to account for this difference. Our approach discussed in this paper enables us to develop reliable and accurate radon flux maps in countries with little or no information on radon flux values.

Manohar, S. N.; Meijer, H. A. J.; Herber, M. A.

2013-12-01

109

Radiation hardness of high resistivity magnetic Czochralski silicon detectors after gamma, neutron, and proton radiations  

Microsoft Academic Search

High resistivity magnetic Czochralski Si detectors were irradiated with 60Co gamma rays, neutrons, and protons to various doses\\/fluences, along with control float zone Si detectors. 1) It has been found that for gamma radiation, magnetic Czochralski Si detectors behave similarly to the high-temperature, long-time (HTLT) oxygenated float zone Si detectors. There is no space charge sign inversion and there is

Zheng Li; Jaakko Harkonen; Wei Chen; J. Kierstead; Panja Luukka; Eija Tuominen; Etuovine Tuovinen; Elea Verbitskaya; Vladimir Eremin

2004-01-01

110

Determination of Soil Water Content From Terrestrial Gamma Radiation Measurements  

NASA Astrophysics Data System (ADS)

Natural gamma radiation emitted by the soil and measured at the surface with a gamma ray spectrometer is a function of the radioactive activity of the soil and the linear attenuation coefficient. The dependence of the linear attenuation coefficient on soil water content is explored for selected soil water profiles by numerical integration. These soil water profiles were generalized distributions based on gravimetric measurements over a sandy soil at the Central Experimental Farm in Ottawa. A comprehensive analysis of the measurements showed that inhomogeneous water distribution accounted for a 1.8% error in the count rate compared to a 2.6% error associated with random count rate fluctuation and instrument error. The depth of the soil layer contributing to natural gamma radiation at the surface depends also on the water content; 90% of the total radiation is contributed by a dry soil of depth 0.18 m, compared to 0.14 m for a soil with a fractional water content of 0.2. The total expected error in the measurement over the range of soil water encountered (0.03-0.24) is shown to be 0.033 for the 0.10-m layer and 0.025 for the 0.25-m layer.

Loijens, H. S.

1980-06-01

111

Impacts of Low-Dose Gamma-Radiation on Genotoxic Risk in Aquatic Ecosystems  

PubMed Central

Chinook salmon cells were exposed to gamma radiation and chromosome damage was assessed using the micronucleus assay. The salmon cells were resistant to radiation at all doses compared to human and mammalian cells. We used an indirect approach to determine if prior low dose exposures at environmental dose levels might alter the consequences of radiation exposures to high doses of radiation (adaptive response). The cells adapted but only at doses which were above levels that might be expected environmentally. The “adaptive response” endpoint was useful to show biological responses to exposure, however, under these conditions it might not help in risk assessment of aquatic organisms since the cells seem to be very resistant and environmental radiation levels are typically extremely low. Preliminary experiments were conducted on two other fish cell model systems (Rainbow Trout and Medaka) to optimize conditions for the micronucleus assay for future environmental radiation studies. Since fish cells appear to be more radiation resistant than mammalian cells, we postulate that radiation risk in the whole organism may also be lower. Therefore whole body studies designed to test effects with the specific aim of assessing relative risk between species are in process. PMID:18648569

Cassidy, Cheryl L.; Lemon, Jennifer A.; Boreham, Douglas R.

2007-01-01

112

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

113

Radiation levels in ancient Egyptian mummies  

NASA Astrophysics Data System (ADS)

Radiation levels were studied in the mummies room and some galleries in the Egyptian museum as well as in the medical museum of the Faculty of Medicine, Cairo University.? and ? radiation levels show almost background values in direct contrast to some mummies in the closed mummies room and inside the glass cases used for protection. Radon decay products in the room atmosphere and inside the glass cases enclosing some mummies show slightly higher levels than the background which were attributed to inefficient ventilation. After reasonable ventilation during the work, these levels apprached the normal values.High resolution ?-ray spectroscopy measurements for the aerosol samples on the filters have shown background values.The results indicated that the mummies do not contain any radioactivity content or any radioactive sources as was previously suggested.

Hussein, Mohamed I.; Hussein, A. Z.; Barakat, M. F.; Nakhla, S.; Iskander, N.

1994-07-01

114

Modern Methods of Real-Time Gamma Radiation Monitoring for General Personal Protection  

NASA Astrophysics Data System (ADS)

Real-time radiation detectors become an essential part of emergency personnel who may have to respond to unknown accidents, incidents or terrorist attacks, which could involve radioactive material. More and more ordinary citizens are interested in personal radiation protection as well. Reasons include lost sources, nuclear industrial accidents, nuclear or radiological terrorism and the possibility of nuclear weapons being used in a war. People want to have the ability to measure it for themselves and they want to be notified when the radiation levels are increased. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the sensor performance through both the material properties and manufacturing technologies. Deep understanding of physical properties of the materials under the influence of radiation exposure is vital for the effective design of dosimeter devices. Detection of radiation is based on the fact that both the electrical and the optical properties of the materials undergo changes upon the exposure to ionizing radiation. It is believed that radiation causes structural defects. The influence of radiation depends on both the dose and the parameters of the films including their thickness: the degradation is more severe for the higher dose and the thinner films. This paper presents overview of modern methods of real-time gamma radiation monitoring for personal protection of radiation workers and general public and suggests further developments in this area.

Korostynska, O.; Arshak, K.; Arshak, A.; Vaseashta, Ashok

115

The origin of the diffuse background gamma radiation  

NASA Technical Reports Server (NTRS)

Recent observations provided evidence for diffuse background gamma radiation extending to energies beyond 100 MeV, and evidence of isotropy and implied cosmological origin. Significant features in the spectrum of this background radiation were observed which provide evidence for its origin in nuclear processes in the early stages of big-bang cosmology, and connect these processes with the galaxy formation theory. A test of the theory is in future observations of the background radiation in the 100 MeK to 100 GeV energy range which are made with large orbiting spark-chamber satellite detectors. The theoretical interpretations of present data, their connection with baryon-symmetric cosmology and galaxy formation theory, and the need for future observations are discussed.

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

1974-01-01

116

Breeding biology of tree swallows and house wrens in a gradient of gamma radiation  

Microsoft Academic Search

In a gradient of gamma radiation ranging from 38.7 mC.kg⁻¹.d⁻¹ to background levels of 0.05 ..mu..C.kg⁻¹.d⁻¹, Tree Swallows (Iridoprocne bicolor) and House Wrens (Troglodytes aedon) avoided nesting in areas of high radiation. Nest boxes selected by swallows and wrens had a mean exposure rate of only 9.3 and 6.6 ..mu..C.kg⁻¹.d⁻¹, respectively. Lateral and canopy vegetation indices and nest hole height

R. Zach; K. R. Mayoh

1982-01-01

117

Gamma thermometer based reactor core liquid level detector  

DOEpatents

A system is provided which employs a modified gamma thermometer for determining the liquid coolant level within a nuclear reactor core. The gamma thermometer which normally is employed to monitor local core heat generation rate (reactor power), is modified by thermocouple junctions and leads to obtain an unambiguous indication of the presence or absence of coolant liquid at the gamma thermometer location. A signal processor generates a signal based on the thermometer surface heat transfer coefficient by comparing the signals from the thermocouples at the thermometer location. The generated signal is a direct indication of loss of coolant due to the change in surface heat transfer when coolant liquid drops below the thermometer location. The loss of coolant indication is independent of reactor power at the thermometer location. Further, the same thermometer may still be used for the normal power monitoring function.

Burns, Thomas J. (Knoxville, TN)

1983-01-01

118

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

119

Biological wound dressings sterilized with gamma radiation: Mexican clinical experience  

NASA Astrophysics Data System (ADS)

Biological wound dressings sterilized with gamma radiation, such as amnion and pig skin, are a reality in Mexico. These tissues are currently processed in the tissue bank and sterilized in the Gamma Industrial Irradiation Plant; both facilities belong to the Instituto Nacional de Investigaciones Nucleares (ININ) (National Institute of Nuclear Research). With the strong support of the International Atomic Energy Agency, the bank was established at the ININ and the Mexican Ministry of Health issued its sanitary license on July 7, 1999. The Quality Management System of the bank was certified by ISO 9001:2000 on August 1, 2003; the scope of the system is "Research, Development and Processing of Biological Tissues Sterilized with Gamma Radiation". At present, more than 150 patients from 16 hospitals have been successfully treated with these tissues. This paper presents a brief description of the tissue processing, as well as the present Mexican clinical experience with children and adult patients who underwent medical treatment with radiosterilized amnion and pig skin, used as biological wound dressings on burns and ocular surface disorders.

Martínez-Pardo, M. E.; Ley-Chávez, E.; Reyes-Frías, M. L.; Rodríguez-Ferreyra, P.; Vázquez-Maya, L.; Salazar, M. A.

2007-11-01

120

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

121

Calculations of background beta-gamma radiation dose through geologic time.  

PubMed

Life on earth is exposed to a background level of ionizing radiation from a number of sources, including beta and gamma radiation from geologic and biologic materials. Radiation dose from geologic emitters has changed because of the chemical evolution of the continental crust, changes in the relative abundances of 235U and 238U, and the radioactive decay of uranium, thorium, and 40K with time. The radiation dose from internal 40K has decreased by a factor of about eight because of changes in the activity concentration of 40K in potassium over the past 4 billion years. Radiation exposure from geologic materials has decreased from about 1.6 mGy y(-1) to 0.66 mGy y(-1) over the past 4 billion years, and radiation exposure to an organism with a potassium concentration of 250 mmol L(-1) has decreased from about 5.5 to about 0.70 mGy y(-1). Accordingly, background radiation exposure from these two sources has dropped from about 7.0 to 1.35 mGy y(-1) during the time life has existed on Earth. The conservative nature of mutation repair mechanisms in modern organisms suggest that these mechanisms may have evolved in the distant past and that organisms may retain some of the capability of efficiently repairing damage from higher radiation levels than exist at present. PMID:10568545

Karam, P A; Leslie, S A

1999-12-01

122

Improvement of PVC floor tiles by gamma radiation  

NASA Astrophysics Data System (ADS)

Gamma radiation presents a unique method of transforming highly plasticized PVC floor tiles, manufactured at high speed through injection moulding, into a high quality floor covering at a cost at least 30% less than similarly rated rubber tiles. A specially formulated PVC compound was developed in collaboration with a leading manufacturer of floor tiles. These tiles are gamma crosslinked in its shipping cartons to form a dimensionally stable product which is highly fire resistant and inert to most chemicals and solvents. The crosslinked tiles are more flexible than the highly filled conventional PVC floor tiles, scratch resistant and have a longer lifespan and increased colour fastness. These tiles are also less expensive to install than conventional rubber tiles.

du Plessis, T. A.; Badenhorst, F.

123

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

124

Ris-M-2270 SHIELDING FACTORS FOR GAMMA RADIATION PROM ACTIVITY DEPOSITED  

E-print Network

Risø-M-2270 SHIELDING FACTORS FOR GAMMA RADIATION PROM ACTIVITY DEPOSITED ON STRUCTURES AND GROUND- MINATION; DOSE RATES; EXTERNAL IRRADIATION; FALLOUT DEPOSITS; GAMMA RADIATION; RADIATION DOSES; SHIELDING SURFACES. Per Hedemann Jensen Abstract. This report describes a computer model that calcu- lates shielding

125

RIS-M-2339 SHIELDING FACTORS FOR VEHICLES TO GAMMA RADIATION FROM  

E-print Network

RISÃ?-M-2339 SHIELDING FACTORS FOR VEHICLES TO GAMMA RADIATION FROM ACTIVITY DEPOSITED ON STRUCTURES Repro 1982 #12;CONTENTS Page 1. INTRODUCTION 5 2. STRUCTURAL SHIELDING AGAINST RADIATION FROM A SURFACE determined for gamma radiation from deposited 1 ^7 Cs. Corrections for mut.'al shielding by nearby buildings

126

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

127

Ceramic Matrix Composites Performances Under High Gamma Radiation Doses  

NASA Astrophysics Data System (ADS)

Ceramic matrix composites reinforced by continuous ceramic fibers (CMCs) represent a class of advanced materials developed for applications in automotive, aerospace, nuclear fusion reactors and in other specific systems for harsh environments. In the present work, the silicon carbide/silicon carbide (SiCf/SiC) composites, manufactured by Chemical Vapour Infiltration process at FN S.p.A. plant, have been evaluated in term of gamma radiation hardness at three different absorbed doses (up to around 3MGy). Samples behavior has been investigated before and after irradiation by means of mechanical tests (flexural strength) and by surface and structural analyses (X-ray diffraction, SEM, FTIR-ATR, EPR).

Cemmi, A.; Baccaro, S.; Fiore, S.; Gislon, P.; Serra, E.; Fassina, S.; Ferrari, E.; Ghisolfi, E.

2014-06-01

128

Some problems in determining level density and radiative strength functions in light and near-magic nuclei  

E-print Network

The values of some functional dependencies of level density and radiative strength functions that reproduce the experimental intensities of the two-step gamma-cascades to the ground and first excited states of 28Al have been determined. It was shown that the assumption about independence of the dipole cascade transitions radiative strength functions on energy of decaying level leads to rather essential error in observation of both level density and radiative strength functions.

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

2005-11-07

129

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

130

An experimental search for gamma radiation associated with thunderstorm activity  

SciTech Connect

This experiment is a repeat of an earlier experiment, but with more sensitive apparatus and in a location with a higher incidence of thunderstorm activity. The earlier experiment was undertaken by Ashby and Whitehead to investigate the theory that ball lightning might be associated with the annihilation of small amounts of antimatter, and it yielded some very interesting but inconclusive results. In the course of about 12 months of data taking, four high rate bursts of gamma radiation were detected. These events lasted a few seconds and had many thousands of counts (16500, 5000, 3700, and [gt] 7700. Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole about 100 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 keV positron annihilation line. While the peak could not be unambiguously attributed to positron annihilation, this certainly appeared to be the most likely source.

Fryberger, D.

1992-11-01

131

An experimental search for gamma radiation associated with thunderstorm activity  

SciTech Connect

This experiment is a repeat of an earlier experiment, but with more sensitive apparatus and in a location with a higher incidence of thunderstorm activity. The earlier experiment was undertaken by Ashby and Whitehead to investigate the theory that ball lightning might be associated with the annihilation of small amounts of antimatter, and it yielded some very interesting but inconclusive results. In the course of about 12 months of data taking, four high rate bursts of gamma radiation were detected. These events lasted a few seconds and had many thousands of counts (16500, 5000, 3700, and {gt} 7700. Unfortunately, the association of these gamma ray bursts with thunderstorms or ball lightning was not clearly established, although one of the bursts did occur during a local thunderstorm in rough coincidence with a lightning bolt striking a flagpole about 100 yards from the gamma ray detection crystals. A pulse height spectrum taken for this burst (no spectrum was taken for the other three) exhibited a significant peak, well above background, the energy of which appeared to be compatible with the 511 keV positron annihilation line. While the peak could not be unambiguously attributed to positron annihilation, this certainly appeared to be the most likely source.

Fryberger, D.

1992-11-01

132

Gamma radiation effects on commercial Mexican bread making wheat flour  

NASA Astrophysics Data System (ADS)

Gamma irradiation is considered to be an alternative method for food preservation to prevent food spoilage, insect infestation and capable of reducing the microbial load. In the present investigation, commercial Mexican bread making wheat flour was irradiated at 1.0 kGy using a 60C Gammabeam 651 PT irradiator facility. No changes were detected in moisture, protein and ashes in gamma irradiated samples as compared to those of non-irradiated samples. Slight radiation effects were observed in the alveogram values and farinograph properties; the falling number decreased 11%, the absorption as well as the mixing tolerance were practically unchanged by irradiation. An increase of 15% in the stability value and a 29% in the dough development time were observed. Also the deformation energy decreased 7% with no change at all in the tenacity/extensibility factor. Total aerobic, yeast and mold counts were reduced 96%, 25% and 75%; respectively by the irradiation process. The obtained results confirm that gamma irradiation is effective in reducing the microbial load in bread making wheat flour without a significant change in the physicochemical and baking properties.

Agúndez-Arvizu, Z.; Fernández-Ramírez, M. V.; Arce-Corrales, M. E.; Cruz-Zaragoza, E.; Meléndrez, R.; Chernov, V.; Barboza-Flores, M.

2006-04-01

133

Level densities and radiative strength functions  

NASA Astrophysics Data System (ADS)

This paper presents a summary of the latest results from experiments performed at the Oslo Cyclotron. The Oslo group has developed a technique to extract simultaneously the level density and radiative strength function from primary ?-ray spectra. A small (pygmy) resonance in the radiative strength function has been observed at around 3 MeV in several deformed rare earth nuclei. This resonance is shown to be of M1 character and the origin is thought to be the scissors mode. This resonance vanishes for the spherical Sm nuclei, as expected, since the scissors mode is dependent on deformation. Experiments performed in Oslo found the resonance in Dy isotopes to be twice as wide as the width extracted in an indirect way by comparing simulations with two-step cascade spectra from neutron capture experiments. In 116,117Sn an increase in the slope of the radiative strength function around E? = 4.5 MeV indicates the onset of resonance-like structures in both nuclei, resulting in a significant enhancement of the radiative strength functions compared to standard models in the energy region 4.5level density and radiative strength function of 96Mo have been reanalyzed, and the enhanced ? strength for E?<3-4 MeV is confirmed. This enhancement is presently not understood and remains a challenge for theoretical models.

Siem, S.; Agvaanluvsan, U.; Bü; rger, A.; Guttormsen, M.; Larsen, A. C.; Mitchell, G.; Nyhus, H. T.; Chankova, R.; Rekstad, J.; Schiller, A.; Syed, N. U. H.; Toft, H. K.; Tveten, G. M.; Voinov, A.

2009-01-01

134

Effect of Gamma radiation on microbial population of natural casings  

NASA Astrophysics Data System (ADS)

The high microbial load of fresh and dry natural casings increases the risk of meat product contamination with pathogenic microorganisms, agents of foodborn diseases. The aim of this work is to evaluate the killing effect of gamma radiation of the resident microbial population of pork and beef casings, to improve their hygiene and safety. Portions of fresh pork (small intestines and colon) and dry beef casings were irradiated in a Cobalt 60 source with with absorbed doses of 1,2,5 and 10 kGy. The D 10 values of total aerobic microorganisms in the pork casings were 1.65 kGy for colon and 1.54 kGy for small intestine. The D 10 value found in beef dry casings (small intestine) was 10.17 kGy. Radurization with 5 kGy was able to reduce, at least, 6 logs the coliform bacteria in pork casings. The killing effect over faecal Streptococci was 4 logs for pork fresh casings and 2 logs for beef dry casings. Gamma radiation with 5 kGy proved to be a convenient method to reduce substantially the microbial population of pork fresh casings. Otherwise, the microbial population of beef dry casings still resisted to 10 kGy.

Trigo, M. J.; Fraqueza, M. J.

1998-06-01

135

The high-energy diffuse cosmic gamma-ray background radiation from blazars  

NASA Technical Reports Server (NTRS)

We predict the spectrum and flux of the high-energy diffuse cosmic gamma-ray background radiation produced by blazars. Our calculations are based on the Compton Observatory EGRET observations of high-energy gamma-rays from these objects, the Whipple observation of TeV gamma-rays from Mrk 421, and radio population studies of flat-spectrum radio sources. Our statistical analysis gives a result consistent with a linear correlation. We then use the radio luminosity function and redshift evolution to calculate the gamma-ray background. We find that blazars cannot account for the flux level or steep spectrum of the background observed by SAS 2 in the sub-GeV range, but could likely provide the dominant background component in the multi-GeV energy range and above. We predict a differential photon spectral index for this component of about 2 up to about 10 GeV. Above that energy, the spectrum should gradually steepen owing to pair production by interactions of the gamma-rays with intergalactic infrared photons. Using the calculations of this effect by Stecker et al. (1992), we estimate a spectral index of about 3.5 for energies above a TeV.

Stecker, F. W.; Salamon, M. H.; Malkan, M. A.

1993-01-01

136

Comparison of degradation effects induced by gamma radiation and electron beam radiation in two cable jacketing materials  

NASA Astrophysics Data System (ADS)

The radiation degradation behavior of commercial low density polyethylene (LDPE) and ethylene-vinylacetate (EVA) cable materials has been investigated. The changes of mechanical properties, thermooxidative stability and density exhibit different radiation stability towards 60Co-gamma radiation and 160 keV electron beam radiation. This difference reflects much higher penetration of the gamma radiation through the polymeric material as a function of sample thickness. These results are discussed with respect to the role of beta radiation during design basis events in a nuclear power plants. In case when total accidental design basis event (DBE) dose (involving about 80% soft beta radiation) is simulated by 60Co-gamma radiation the conservatism is reached.

Bartoní?ek, B.; Pla?ek, V.; Hnát, V.

2007-05-01

137

Biological radiation dose from secondary particles in a Milky Way gamma-ray burst  

NASA Astrophysics Data System (ADS)

Gamma-ray bursts (GRBs) are a class of highly energetic explosions emitting radiation in a very short timescale of a few seconds and with a very narrow opening angle. Although, all GRBs observed so far are extragalactic in origin, there is a high probability of a GRB of galactic origin beaming towards the Earth in the past ~0.5 Gyr. We define the level of catastrophic damage to the biosphere as approximation 100 kJ m-2, based on Thomas et al. (2005a, b). Using results in Melott & Thomas (2011), we estimate the probability of the Earth receiving this fluence from a GRB of any type, as 87% during the last 500 Myr. Such an intense burst of gamma rays would ionize the atmosphere and deplete the ozone (O3) layer. With depleted O3, there will be an increased flux of Solar UVB on the Earth's surface with potentially harmful biological effects. In addition to the atmospheric damage, secondary particles produced by gamma ray-induced showers will reach the surface. Among all secondary particles, muons dominate the ground-level secondary particle flux (99% of the total number of particles) and are potentially of biological significance. Using the Monte Carlo simulation code CORSIKA, we modelled the air showers produced by gamma-ray primaries up to 100 GeV. We found that the number of muons produced by the electromagnetic component of hypothetical galactic GRBs significantly increases the total muon flux. However, since the muon production efficiency is extremely low for photon energies below 100 GeV, and because GRBs radiate strongly for only a very short time, we find that the biological radiation dose from secondary muons is negligible. The main mechanism of biological damage from GRBs is through Solar UVB irradiation from the loss of O3 in the upper atmosphere.

Atri, Dimitra; Melott, Adrian L.; Karam, Andrew

2014-07-01

138

Relative Biological Effectiveness (RBE) of 131I Radiation Relative to 60Co Gamma Rays  

PubMed Central

Objective: To assess relative biological effectiveness (RBE) of 131I radiation relative to 60Co gamma rays in glioblastoma spheroid cells. Materials and Methods: : In this experimental study, glioblastoma spheroid cells were exposed to 131I radiation and 60Co gamma rays. Radiation induced DNA damage was evaluated by alkaline comet assay. Samples of spheroid cells were treated by radiation from 131I for four different periods of time to find the dose-response equation. Spheroid cells were also exposed by 200 cGy of 60Co gamma rays as reference radiation to induce DNA damage as endpoint. Results: Resulted RBE of 131I radiation relative to 60Co gamma rays in 100 µm giloblastoma spheroid cells was equal to 1.16. Conclusion: The finding of this study suggests that 131I photons and electrons can be more effective than 60Co gamma rays to produce DNA damage in glioblastoma spheroid cells. PMID:24027663

Neshasteh-Riz, Ali; Mahmoud Pashazadeh, Ali; Mahdavi, Seyed Rabie

2013-01-01

139

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

140

Trypanosoma cruzi Gene Expression in Response to Gamma Radiation  

PubMed Central

Trypanosoma cruzi is an organism highly resistant to ionizing radiation. Following a dose of 500 Gy of gamma radiation, the fragmented genomic DNA is gradually reconstructed and the pattern of chromosomal bands is restored in less than 48 hours. Cell growth arrests after irradiation but, while DNA is completely fragmented, RNA maintains its integrity. In this work we compared the transcriptional profiles of irradiated and non-irradiated epimastigotes at different time points after irradiation using microarray. In total, 273 genes were differentially expressed; from these, 160 were up-regulated and 113 down-regulated. We found that genes with predicted functions are the most prevalent in the down-regulated gene category. Translation and protein metabolic processes, as well as generation of precursor of metabolites and energy pathways were affected. In contrast, the up-regulated category was mainly composed of obsolete sequences (which included some genes of the kinetoplast DNA), genes coding for hypothetical proteins, and Retrotransposon Hot Spot genes. Finally, the tyrosyl-DNA phosphodiesterase 1, a gene involved in double-strand DNA break repair process, was up-regulated. Our study demonstrated the peculiar response to ionizing radiation, raising questions about how this organism changes its gene expression to manage such a harmful stress. PMID:22247781

Grynberg, Priscila; Passos-Silva, Danielle Gomes; Mourão, Marina de Moraes; Hirata Jr, Roberto; Macedo, Andrea Mara; Machado, Carlos Renato; Bartholomeu, Daniella Castanheira; Franco, Glória Regina

2012-01-01

141

Effects of acute gamma radiation on the reproductive ability of the earthworm Eisenia fetida.  

PubMed

Earthworms are the most suitable biological indicators of radioactive pollution because they are the parts of nutritional webs, and are present in relatively high numbers. Four months old Eisenia fetida were exposed to different doses of gamma radiation, namely 1, 2, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 & 60 Gy to study the effects of radiation on different reproductive parameters. The number of cocoons laid and the hatchlings emerged were recorded for all the selected doses. There was no reduction in cocoon production, however; decreasing size and weight of the cocoons was observed from the samples exposed to 20 Gy and above doses. Significant reductions in the hatchlings were recorded in earthworms exposed to 10 Gy and above doses. The dose response curves for a percentage reduction in hatchlings were constructed. Exposure to radiation dose of 1 and 2 Gy did not show any reduction, however, there was ?10%, ?50% and ?90% decrease in the hatchlings in samples exposed to 3, 15 and 45, 50, 55 and 60 Gy doses respectively. Delayed hatchability was also reported at al exposure level. Histology of irradiated earthworms revealed that the structural damage in the seminal vesicles was prominent at the exposed dose of 3 Gy onwards with complete degeneration on exposure to 60 Gy of gamma radiation. PMID:25461510

Sowmithra, K; Shetty, N J; Harini, B P; Jha, S K; Chaubey, R C

2015-02-01

142

Neutron and gamma radiation shielding material, structure, and process of making structure  

DOEpatents

The present invention is directed to a novel neutron and gamma radiation elding material consisting of 95 to 97 percent by weight SiO.sub.2 and 5 to 3 percent by weight sodium silicate. In addition, the method of using this composition to provide a continuous neutron and gamma radiation shielding structure is disclosed.

Hondorp, Hugh L. (Princeton Junction, NJ)

1984-01-01

143

Biological effects of low levels of radiation exposure. [Radiation hazards to man from radioactive consumer products  

Microsoft Academic Search

Some general perspective is provided concerning the orders of radiation dose equivalent levels associated with exposure of human populations to ionizing radiations from consumer products. This is followed by considerations of the biological effects and risks of low levels of radiation exposure. Some consumer products emit low-LET (i.e., low linear energy transfer) radiations beyond their confines and these penetrating radiations

Casarett

1977-01-01

144

Population doses from environmental gamma radiation in Iraq.  

PubMed

The exposure rates due to external gamma radiation were measured in 11 Iraqi governerates. Measurements were performed with an Environmental Monitoring System (RSS-111) in open air 1 m above the ground. The average absorbed dose rate in each governerate was as follows (number x 10(-2) microGy h-1): Babylon (6.0), Kerbala (5.3), Al-Najaf (5.4), Al-Kadysia (6.5), Wasit (6.5), Diala (6.5), Al-Anbar (6.5), Al-Muthana (6.6), Maisan (6.8), Thee-Kar (6.6), and Al-Basrah (6.5). The collective doses to the population living in these governerates were 499, 187, 239, 269, 262, 458, 384, 153, 250, 450, and 419 person-Sv, respectively. PMID:1559815

Marouf, B A; Mohamad, A S; Taha, J S; al-Haddad, I K

1992-05-01

145

Radiation resistance of a gamma-ray irradiated nonlinear optic chromophore  

NASA Astrophysics Data System (ADS)

The radiation resistance of organic electro-optic and optoelectronic materials for space applications is receiving increased attention. An earlier investigation reported that guest-host poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- V?) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. To provide further evidences to the observed radiation stability, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data.

Zhang, Cheng; Taylor, Edward W.

2009-11-01

146

Assessment of natural radioactivity concentrations and gamma dose rate levels in Kayseri, Turkey.  

PubMed

This study assesses the level of background radiation for Kayseri province of Turkey. Natural radionuclide activity concentrations in soil samples were determined using high-resolution gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using a portable gamma scintillation detector. The obtained results of uranium and thorium series as well as potassium ((40)K) are discussed. The present data were compared with the data obtained from different areas in Turkey. From the measured gamma-ray spectra, the average activity concentrations were determined for (238)U (range from 3.91 to 794.25 Bq kg(-1)), (232)Th (range from 0.68 to 245.55 Bq kg(-1)) and (40)K (range from 23.68 to 2718.71 Bq kg(-1)). The average activity concentrations of (238)U, (232)Th and (40)K were found to be 35.51, 37.27 and 429.66 Bq kg(-1), respectively, and 11.53 Bq kg(-1) for the fission product (137)Cs. The highest values of (238)U, (232)Th and (40)K concentrations (794.25 Bq kg(-1), 245.55 Bq kg(-1), 2718.71 Bq kg(-1), respectively) were observed in abnormal samples at Hayriye village. The average outdoor gamma dose rate in air at 1 m above the ground was determined as 114.43 nGy h(-1). Using the data obtained in this study, the average annual effective dose for a person living in Kayseri was found to be about 140.34 µSv. PMID:21406430

Otansev, Pelin; Karahan, Gürsel; Kam, Erol; Barut, Ipek; Taskin, Halim

2012-01-01

147

Effects of ionizing radiation (neutrons/gamma rays) on plasma lipids and lipoproteins in rats.  

PubMed

Male Wistar rats weighing 250 g were exposed to 4 Gy of neutrons/gamma radiation (3.33 Gy of neutrons and 0.66 Gy of gamma rays). After whole-body irradiation, plasma cholesterol and phospholipid levels increased up to 62 and 37%, respectively, at day 4 and then returned to control values 12 days after irradiation. Plasma triglyceride concentrations decreased concomitantly with decreased food intake after irradiation but remained higher than in pair-fed control rats. Plasma lipoproteins were separated by ultracentrifugation on a density gradient (1.006-1.210 g/ml). Four days after irradiation, most of the cholesterol (62% compared to 31% in controls, P < 0.001) is transported by apolipoprotein E-rich high-density lipoproteins. At the same time, plasma levels of apolipoproteins B and E were increased by 28 and 65%, respectively, while those of apolipoproteins AI and AIV were reduced by 21 and 59%, respectively. While in the liver of irradiated rats the apolipoprotein B/E receptor number was not modified, the hydroxymethylglutaryl coenzyme A reductase activity was fivefold higher than in control pair-fed rats. Four days after irradiation, the susceptibility of lipoproteins to peroxidation, as measured by the formation of conjugated dienes in the presence of Cu2+, was markedly increased while plasma vitamin E levels were decreased, demonstrating that irradiation reduces antioxidant stores markedly. These results suggest that such modified lipoproteins could be involved in radiation-induced vascular damage. PMID:9650601

Feurgard, C; Bayle, D; Guézingar, F; Sérougne, C; Mazur, A; Lutton, C; Aigueperse, J; Gourmelon, P; Mathé, D

1998-07-01

148

Effects of proton and gamma radiation on lymphocyte populations and acute response to antigen  

NASA Technical Reports Server (NTRS)

BACKGROUND: The clinical use of proton radiation in the management of cancer, as well as benign disorders, is rapidly increasing. The major goal of this study was to compare the effects of proton and gamma (60Co) radiation on cell-mediated and humoral immunological parameters. MATERIALS AND METHODS: C57BL/6 mice were exposed to a single dose of 3 Gray (Gy) protons or gamma-rays and intraperitoneally injected 1 day later with sheep red blood cells (sRBC). On 4, 10, 15, and 29 days after exposure, subsets from each group were euthanised; nonirradiated controls (with and without sRBC injection) were included. Body and relative spleen weights, leukocyte counts, spontaneous blastogenesis, lymphocyte populations, and anti-sRBC titers were evaluated. RESULTS: The data showed significant depression (p < 0.05) in nearly all assays on days 4 and 10 after irradiation. B lymphocytes (CD19+) were the most radiosensitive, although reconstitution back to normal levels was observed by day 15. T cell (CD3+) and T helper cell (CD4+) recovery was evident by day 29, whereas the T cytotoxic cell (CD8+) count remained significantly below normal. Natural killer cells (NK1.1+) were relatively radioresistant. Anti-sRBC antibody production was slow and low titers were obtained after irradiation. No significant differences were noted between the two types of radiation. CONCLUSIONS: Taken together, the data show that whole-body irradiation with protons or gamma-rays, at the dose employed, results in marked, but transient, immunosuppression. However, at the time points of testing and with the assays used, little or no differences were found between the two forms of radiation.

Kajioka, E. H.; Gheorghe, C.; Andres, M. L.; Abell, G. A.; Folz-Holbeck, J.; Slater, J. M.; Nelson, G. A.; Gridley, D. S.

1999-01-01

149

Microbial population, physicochemical quality, and allergenicity of molluscs and shrimp treated with cobalt-60 gamma radiation.  

PubMed

Frozen molluscs (squid, octopuses, and cuttlefish) and crustaceans (shrimp) were irradiated using a cobalt-60 gamma source, at different doses, in order to investigate the effects of gamma radiation on their microbial population, organoleptic characteristics, lipid profile, and tropomyosin content. Irradiation of shrimp and squid with either 2.5 or 4.7 kGy reduced mesophilic bacteria contamination to low or nondetectable levels, respectively, whereas irradiation of octopus and cuttlefish with the same doses reduced the bacterial population. Irradiation treatment had no significant (P > 0.05) effect on the total lipid content and the major detected classes of polar and neutral lipids, whereas it significantly (P < 0.05) increased the contents of neutral lipids in octopus mantle and in shrimp muscle and cephalothorax samples. The total fatty acid content and the omega-3: omega-6 fatty acid ration was not affected. A dose-dependent significant (P < 0.05) decrease in the ratio of polyunsaturated fatty acids:saturated fatty acids was observed. With the increase in radiation dose, redness (a) and yellowness (b) values showed a variation, whereas the lightness (L) value was significantly (P < 0.05) decreased in mollusc mantles and shrimp muscle and increased in shrimp cephalothorax. The total of color changes ( delta E) increased (P < 0.05) as the dose increased. Significant (P < 0.05) changes in textural properties were observed with radiation treatment in octopus tentacles and in squid and cuttlefish mantle. The amount of tropomyosin, which is the major mollusc and crustacean allergen in the irradiated organisms, was reduced by gamma radiation, depending on the dose. PMID:17477267

Sinanoglou, Vassilia J; Batrinou, Anthimia; Konteles, Spyros; Sflomos, Konstantinos

2007-04-01

150

Mediate gamma radiation effects on some packaged food items  

NASA Astrophysics Data System (ADS)

For most of prepackaged foods a 10 kGy radiation dose is considered the maximum dose needed; however, the commercially available and practically accepted packaging materials must be suitable for such application. This work describes the application of ionizing radiation on several packaged food items, using 5 dehydrated food items, 5 ready-to-eat meals and 5 ready-to-eat food items irradiated in a 60Co gamma source with a 3 kGy dose. The quality evaluation of the irradiated samples was performed 2 and 8 months after irradiation. Microbiological analysis (bacteria, fungus and yeast load) was performed. The sensory characteristics were established for appearance, aroma, texture and flavor attributes were also established. From these data, the acceptability of all irradiated items was obtained. All ready-to-eat food items assayed like manioc flour, some pâtés and blocks of raw brown sugar and most of ready-to-eat meals like sausages and chicken with legumes were considered acceptable for microbial and sensory characteristics. On the other hand, the dehydrated food items chosen for this study, such as dehydrated bacon potatoes or pea soups were not accepted by the sensory analysis. A careful dose choice and special irradiation conditions must be used in order to achieve sensory acceptability needed for the commercialization of specific irradiated food items.

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

2012-08-01

151

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

152

Dose-dependent hepatic transcriptional responses in Atlantic salmon (Salmo salar) exposed to sublethal doses of gamma radiation.  

PubMed

Due to the production of free radicals, gamma radiation may pose a hazard to living organisms. The high-dose radiation effects have been extensively studied, whereas the ecotoxicity data on low-dose gamma radiation is still limited. The present study was therefore performed using Atlantic salmon (Salmo salar) to characterize effects of low-dose (15, 70 and 280mGy) gamma radiation after short-term (48h) exposure. Global transcriptional changes were studied using a combination of high-density oligonucleotide microarrays and quantitative real-time reverse transcription polymerase chain reaction (qPCR). Differentially expressed genes (DEGs; in this article the phrase gene expression is taken as a synonym of gene transcription, although it is acknowledged that gene expression can also be regulated, e.g., at protein stability and translational level) were determined and linked to their biological meanings predicted using both Gene Ontology (GO) and mammalian ortholog-based functional analyses. The plasma glucose level was also measured as a general stress biomarker at the organism level. Results from the microarray analysis revealed a dose-dependent pattern of global transcriptional responses, with 222, 495 and 909 DEGs regulated by 15, 70 and 280mGy gamma radiation, respectively. Among these DEGs, only 34 were commonly regulated by all radiation doses, whereas the majority of differences were dose-specific. No GO functions were identified at low or medium doses, but repression of DEGs associated with GO functions such as DNA replication, cell cycle regulation and response to reactive oxygen species (ROS) were observed after 280mGy gamma exposure. Ortholog-based toxicity pathway analysis further showed that 15mGy radiation affected DEGs associated with cellular signaling and immune response; 70mGy radiation affected cell cycle regulation and DNA damage repair, cellular energy production; and 280mGy radiation affected pathways related to cell cycle regulation and DNA repair, mitochondrial dysfunction and immune functions. Twelve genes representative of key pathways found in this study were verified by qPCR. Potential common MoAs of low-dose gamma radiation may include induction of oxidative stress, DNA damage and disturbance of oxidative phosphorylation (OXPHOS). Although common MoAs were proposed, a number of DEGs and pathways were still found to be dose-specific, potentially indicating multiple mechanisms of action (MOAs) of low-dose gamma radiation in fish. In addition, plasma glucose displayed an apparent increase with increasing radiation doses, although the results were not significantly different from the control. These findings suggested that sublethal doses of gamma radiation may cause dose-dependent transcriptional changes in the liver of Atlantic salmon after short-term exposure. The current study predicted multiple MoA for gamma radiation and may aid future impact assessment of environmental radioactivity in fish. PMID:25146236

Song, You; Salbu, Brit; Teien, Hans-Christian; Heier, Lene Sørlie; Rosseland, Bjørn Olav; Tollefsen, Knut Erik

2014-11-01

153

Health effects of low-level radiation  

Microsoft Academic Search

This book presents papers on the uses and biological effects of radiation. Topics considered include low dose irradiation, radiation sources, radiation measurements, dosimetry, epidemiology, cancer risk, dose-response relationships, x-ray radiography, genetic consequences, radiation protection, legal aspects, plutonium release from the Rocky Flats Plant, and radioactive waste management.

Hendee

1984-01-01

154

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

155

Experimental Level Densities and {gamma}-Strength Functions in rare earth nuclei  

SciTech Connect

The level density and radiative strength function for {sup 146,147}Sm and {sup 163,164}Dy have been extracted from primary {gamma} spectra using the Oslo method. As one approaches the closed N = 82 neutron shell, the structures in the level density become more pronounced due to shell effects. The experimental level densities can be used to explore thermodynamic properties of the nucleus within the microcanonical ensemble. Pygmy resonances, which are based on the scissors mode and seen in deformed rare-earth nuclei, are not observed in near-spherical {sup 146,147}Sm, as expected. Pygmy resonances in {sup 163,164}Dy were studied after {sup 3}He-induced reactions and their width was found to be twice as wide as compared to results reported after neutron-capture reactions.

Siem, S.; Guttormsen, M.; Larsen, A. C.; Nyhus, H. T.; Ingebretsen, F.; Messelt, S.; Rekstad, J.; 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, NC 27695 (United States); Triangle Universities Nuclear Laboratory Durham, NC 27708 (United States); Schiller, A. [Department of Physics and Astronomy Ohio University, Athens, Ohio 45701 (United States); Voinov, A. [Department of Physics and Astronomy Ohio University, Athens, Ohio 45701 (United States); Frank Laboratory of Neutron Physics, Joint Institute of Nuclear Research, 141980 Dubna, Moscow region (Russian Federation); Oedegaard, S. W. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Norwegian Defence Research Establishment, P.O. Box 25, N-2027 Kjeller (Norway)

2008-04-17

156

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

157

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

158

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

159

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

160

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

161

Radiation Metabolomics: Identification of Minimally Invasive Urine Biomarkers for Gamma-Radiation Exposure in Mice  

PubMed Central

Gamma-radiation exposure has both short- and long-term adverse health effects. The threat of modern terrorism places human populations at risk for radiological exposures, yet current medical countermeasures to radiation exposure are limited. Here we describe metabolomics for ?-radiation biodosimetry in a mouse model. Mice were ?-irradiated at doses of 0, 3 and 8 Gy (2.57 Gy/min), and urine samples collected over the first 24 h after exposure were analyzed by ultra-performance liquid chromatography–time-of-flight mass spectrometry (UPLC–TOFMS). Multivariate data were analyzed by orthogonal partial least squares (OPLS). Both 3- and 8-Gy exposures yielded distinct urine metabolomic phenotypes. The top 22 ions for 3 and 8 Gy were analyzed further, including tandem mass spectrometric comparison with authentic standards, revealing that N-hexanoylglycine and ?-thymidine are urinary biomarkers of exposure to 3 and 8 Gy, 3-hydroxy-2-methylbenzoic acid 3-O-sulfate is elevated in urine of mice exposed to 3 but not 8 Gy, and taurine is elevated after 8 but not 3 Gy. Gene Expression Dynamics Inspector (GEDI) self-organizing maps showed clear dose–response relationships for subsets of the urine metabolome. This approach is useful for identifying mice exposed to ? radiation and for developing metabolomic strategies for noninvasive radiation biodosimetry in humans. PMID:18582157

Tyburski, John B.; Patterson, Andrew D.; Krausz, Kristopher W.; Slavík, Josef; Fornace, Albert J.; Gonzalez, Frank J.; Idle, Jeffrey R.

2008-01-01

162

The use of calcite mineral thermoluminescence for the determination of previously received gamma radiation dose in foodstuffs\\/E1 uso de la termoluminiscencia de la calcita para la determinación de la dosis de radiación gamma de alimentos previamente irradiados  

Microsoft Academic Search

This paper describes the potential use of calcite mineral dust as a high-dose radiation dosemeter. The results obtained show that saturation dose in natural calcite is of the order of 7 kGy. Measurements of absorbed dose, for samples previously irradiated with known gamma doses, showed a good level of agreement between actual doses and calculated doses, although the level of

M. Urbina; P. Beneitez; A. Millán; T. Calderón

1996-01-01

163

Gamma Ray Telescope Senses High-Energy Radiation  

NSDL National Science Digital Library

This video from NASA describes the GLAST satellite, which is equipped with a gamma-ray telescope, and shares some background about the kinds of extreme universal phenomena indicated by the presence of gamma rays.

WNET

2011-11-02

164

Environmental gamma radiation measurements on the island of Pantelleria.  

PubMed

The population exposure to those living on the island of Pantelleria, Italy, was estimated by measuring the natural gamma background. Gamma spectra of natural rocks and measurements of absorbed dose in air were taken. A correlation was found between the mean gamma exposure rate and the mean values of natural radionuclide concentrations in the investigated rocks. PMID:1644574

Brai, M; Bellia, S; Di Liberto, R; Dongarra, G; Hauser, S; Parello, F; Puccio, P; Rizzo, S

1992-09-01

165

Virtuality Distributions in application to gamma gamma* to pi^0 Transition Form Factor at Handbag Level  

SciTech Connect

We outline basics of a new approach to transverse momentum dependence in hard processes. As an illustration, we consider hard exclusive transition process gamma*gamma -> to pi^0 at the handbag level. Our starting point is coordinate representation for matrix elements of operators (in the simplest case, bilocal O(0,z)) describing a hadron with momentum p. Treated as functions of (pz) and z^2, they are parametrized through a virtuality distribution amplitude (VDA) Phi (x, sigma), with x being Fourier-conjugate to (pz) and sigma Laplace-conjugate to z^2. For intervals with z^+=0, we introduce transverse momentum distribution amplitude (TMDA) Psi (x, k_\\perp), and write it in terms of VDA Phi (x, \\sigma). The results of covariant calculations, written in terms of Phi (x sigma) are converted into expressions involving Psi (x, k_\\perp. Starting with scalar toy models, we extend the analysis onto the case of spin-1/2 quarks and QCD. We propose simple models for soft VDAs/TMDAs, and use them for comparison of handbag results with experimental (BaBar and BELLE) data on the pion transition form factor. We also discuss how one can generate high-k_\\perp tails from primordial soft distributions.

Radyushkin, Anatoly V. [ODU, JLAB

2014-07-01

166

Natural gamma-radiation in the Aeolian volcanic arc.  

PubMed

Pulse-height distributions of gamma-rays, obtained with a field NaI(Tl) scintillation spectrometer in numerous sites of the Lipari and Vulcano islands (Aeolian volcanic arc, Italy), were measured to determine the U, Th and K concentrations of the bedrock and the relative values of the air absorbed dose rate. U is spatially related to both Th and K and the Th/U ratio is on average 3.1-3.5. The magmatic evolution is reflected by the concentration of the three radioelements, as they are more abundant within the more felsic units of the volcanic series. The higher values of U (15.7-20.0 ppm) coincide with higher Th (48.3-65.9 ppm) and K (4.9-6.1%) concentrations associated with rhyolitic rocks of the third cycle (< 50 ky). The air absorbed dose rate varies from 20 to 470 nGy h(-1). The highest values (> 350 nGy h(-1)) are observed on outcrops of rhyolitic obsidian lava flows. The cosmic-ray contribution is also evaluated to estimate the total background radiation dose rate. PMID:11573810

Chiozzi, P; Pasquale, V; Verdoya, M; Minato, S

2001-11-01

167

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

168

Gamma radiation effect on gas production in anion exchange resins  

NASA Astrophysics Data System (ADS)

Radiation-induced decomposition of Amberlite IRA400 anion exchange resin in hydroxide form by gamma radiolysis has been studied at various doses in different atmospheres (anaerobic, anaerobic with liquid water, and aerobic). The effect of these parameters on the degradation of ion exchange resins is rarely investigated in the literature. We focused on the radiolysis gases produced by resin degradation. When the resin was irradiated under anaerobic conditions with liquid water, the liquid phase over the resin was also analyzed to identify any possible water-soluble products released by degradation of the resin. The main products released are trimethylamine (TMA), molecular hydrogen (H2g) and carbon dioxide (CO2g). TMA and H2g are produced in all the irradiation atmospheres. However, TMA was in gaseous form under anaerobic and aerobic conditions and in aqueous form in presence of liquid water. In the latter conditions, TMAaq was associated with aqueous dimethylamine (DMAaq), monomethylamine (MMAaq) and ammonia (NH). CO2g is formed in the presence of oxygen due to oxidation of organic compounds present in the system, in particular the degradation products such as TMAg.

Traboulsi, A.; Labed, V.; Dauvois, V.; Dupuy, N.; Rebufa, C.

2013-10-01

169

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

170

Effect of gamma radiation on the inactivation of aflatoxin B1 in food and feed crops.  

PubMed

Samples of food crops (peanut, peeled pistachio, unpeeled pistachio, rice, and corn) and feed (barley, bran, corn) were autoclave-sterilized, and inoculated with 10(6) of spore suspension of an isolate of Aspergillus flavus fungus known to produce aflatoxin B1 (AFB1) . Following a 10-day period of incubation at 27 C to allow for fungal growth, food and feed samples were irradiated with gamma radiation at the doses 4, 6, and 10 kGy. Results indicated that degradation of AFB1 was positively correlated with the increase in the applied dose of gamma ray for each tested sample. At a dose of 10 kGy percentages of AFB1 degradation reached highest values at 58.6, 68.8, 84.6, 81.1 and 87.8% for peanuts, peeled pistachios, unpeeled pistachios, corn and rice samples, respectively. In feed samples percentages of AFB1 degradation were 45, 66, and 90% in barley, 47, 75, and 86% in bran, and 31, 72, and 84% in corn for the doses of 4, 6, and 10 kGy, respectively. AFB1 degradation in food samples correlated negatively with oil content in irradiated samples. Thus, in peanuts, which contained the highest oil content, percentage of AFB1 degradation at 10 kGy was not more than 56.6%, whereas, the corresponding value in corn, which contained the lowest oil content, reached as high as 80%. The above results indicate the possibility of using gamma radiation as a means of degradation of AFB1 in food and feed crops to levels lower than the maximum allowed levels. PMID:24031308

Ghanem, I; Orfi, M; Shamma, M

2008-10-01

171

Low-Level Radiation: A High-Level Concern  

Microsoft Academic Search

The role of DOE in radiation health effects research is discussed. The possibility of conflict of interest is presented. The Mancuso episode is cited as evidence. The roles of several agencies (EPA, NRC, and OSHA) in establishing safe limits of radiation exposure are discussed.

Constance Holden

1979-01-01

172

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

173

Some neutron and gamma radiation characteristics of plutonium cermet fuel for isotopic power sources  

NASA Technical Reports Server (NTRS)

Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of O-17, O-18 F-19, Pu-236, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from present plutonium-molybdenum cermet fuel, while both fluorine and Pu-236 daughters contribute significantly to the gamma ray intensities.

Neff, R. A.; Anderson, M. E.; Campbell, A. R.; Haas, F. X.

1972-01-01

174

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

175

Detection system for high-resolution gamma radiation spectroscopy with neutron time-of-flight filtering  

DOEpatents

A .gamma.-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive .alpha.-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a .gamma.-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the .gamma.-radiation. Subsequently, it is determined whether a coincidence exists between the .alpha.-particles and .gamma.-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the .alpha.-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

Dioszegi, Istvan; Salwen, Cynthia; Vanier, Peter

2014-12-30

176

Aflatoxins and ochratoxin a reduction in black and white pepper by gamma radiation  

NASA Astrophysics Data System (ADS)

Irradiation is an important means of decontamination of food commodities, especially spices. The aim of the current study was to investigate the efficacy of gamma radiation (60Co) for decontaminating ochratoxin A (OTA) and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) residues in artificially contaminated black and white pepper samples. The moisture content of the pepper samples was set at 12% or 18%, and the applied gamma dose ranged from 5 to 30 kGy. Mycotoxin levels were determined by high-performance liquid chromatography (HPLC) after immunoaffinity column (IAC) chromatography. Both the gamma irradiation dose and moisture content showed significant effects (P<0.05) on mycotoxin reduction. The maximum toxin reductions, found at 18% moisture content and 30 kGy, were 55.2%, 50.6%, 39.2%, 47.7% and 42.9% for OTA, AFB1, AFB2, AFG1 and AFG2, respectively.

Jalili, M.; Jinap, S.; Noranizan, M. A.

2012-11-01

177

Dosimetry of mixed neutron and gamma radiation with paired Fricke solutions in light and heavy water.  

PubMed

Paired Fricke solutions, made up from light water or heavy water and 0.8N in H2SO4 and 1 mM in Fe(NH4)2(SO4)2 and NaCl, were calibrated with 60Co gamma rays and with mixed neutron and gamma radiation from a 252Cf source. Absorbance increases, AL and AH, in light- and heavy-water Fricke dosimeters, respectively, increased with fast-neutron and gamma-ray tissue doses, Dn (GY) and D gamma (GY), of the mixed radiation as follows: AL = 0.00178Dn + 0.00371D gamma; AH = 0.00121Dn + 0.00442 D gamma. G-values of 7.2 and 5.5 were obtained for 252Cf neutrons in light- and heavy-water Fricke dosimeters, respectively. When we applied the pair of equations to AL and AH values observed after exposure to mixed radiation in a nuclear reactor, resulting Dn and D gamma values agreed within 10% to doses measured with paired ionization chambers. Doses required for Fricke dosimeters were 5 Gy or more. In contrast, we found that micronuclear yields in onion roots can measure the neutron component of mixed radiation fields at the order of 10 cGy with reasonable accuracy even if the neutron to gamma-ray dose ratio is unknown. PMID:8840720

Himit, M; Itoh, T; Endo, S; Fujikawa, K; Hoshi, M

1996-06-01

178

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.

179

A comparison of gamma and proton radiation effects in 200 GHz SiGe HBTs  

Microsoft Academic Search

We present the results of gamma irradiation on third-generation, 200 GHz SiGe HBTs. Pre- and post-radiation dc figures-of-merit are used to quantify the tolerance of the raised extrinsic base structure to Co-60 gamma rays for varying device geometries. Additionally, the impact of technology scaling on the observed radiation response is addressed through comparisons to second generation, 120 GHz SiGe HBTs.

Akil K. Sutton; Becca M. Haugerud; A. P. Gnana Prakash; Bongim Jun; John D. Cressler; Cheryl J. Marshall; Paul W. Marshall; Ray Ladbury; Fernando Guarin; Alvin J. Joseph

2005-01-01

180

Deinococcus puniceus sp. nov., a Bacterium Isolated from Soil-Irradiated Gamma Radiation.  

PubMed

A Gram-positive, coccus-shaped, crimson-color-pigmented bacterium was isolated from soil irradiated with 5 kGy gamma radiation and was designated strain DY1(T). Cells showed growth at 10-30 °C and pH 7-11 and were oxidase-negative and catalase-positive. Phylogenetic analyses of the 16S rRNA gene showed that the strain DY1(T) belonged to the genus Deinococcus with sequence similarities to Deinococcus aquatilis CCUG 53370(T) (96.2 %) and Deinococcus navajonensis KR-114(T) (94.1 %). Strain DY1(T) showed low level of DNA relatedness with D. aquatilis CCUG 53370(T) (41.3 ± 3.9 %). The DNA G + C content of DY1(T) was 58.7 mol%. Predominant fatty acids were summed feature 3 (C16:1 ?7c/?6c), C16:0, and C17:0. The major amino acids were D-alanine, L-glutamic acid, glycine, and L-ornithine in the peptidoglycan. The major polar lipids were unknown phosphoglycolipids (PGL). Strain DY1(T) has resistance to gamma radiation and was found to be a novel species. Therefore, the strain was designated as DY1(T) (=KCTC 33027(T) = JCM 18576(T)), and the name Deinococcus puniceus sp. nov. is herein proposed. PMID:25477066

Lee, Jae-Jin; Srinivasan, Sathiyaraj; Lim, Sangyong; Joe, Minho; Im, Seonghun; Kim, Myung Kyum

2014-12-01

181

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

182

Geraniin down regulates gamma radiation-induced apoptosis by suppressing DNA damage.  

PubMed

Gamma ray irradiation triggers DNA damage and apoptosis of proliferating stem cells and peripheral immune cells, resulting in the destruction of intestinal crypts and lymphoid system. Geraniin is a natural compound extracts from an aquatic plant Nymphaea tetragona and possesses good antioxidant property. In this study, we demonstrate that geraniin rescues radiosensitive splenocytes and jejunal crypt cells from radiation-induced DNA damage and apoptosis. Isolated splenocytes from C57BL/6 mice treated with geraniin were protected against radiation injury of 2 Gy irradiation through the enhancement of the proliferation and attenuation of DNA damage. Also, geraniin inhibited apoptosis in radiosensitive splenocytes by reducing the expression level and immunoreactivity of proapoptotic p53 and Bax and increasing those of anti-apoptotic Bcl-2. In mice exposed to radiation, geraniin treatment protected splenocytes and intestinal crypt cells from radiation-induced cell death. Our results suggest that geraniin presents radioprotective effects by regulating DNA damage on splenocytes, exerting immunostimulatory capacities and inhibiting apoptosis of radiosensitive immune cells and jejunal crypt cells. Therefore, geraniin can be a radioprotective agent against ?-irradiation exposure. PMID:23541438

Bing, So Jin; Ha, Danbee; Kim, Min Ju; Park, Eunjin; Ahn, Ginnae; Kim, Dae Seung; Ko, Ryeo Kyeong; Park, Jae Woo; Lee, Nam Ho; Jee, Youngheun

2013-07-01

183

Shelf life extension of fresh turmeric ( Curcuma longa L.) using gamma radiation  

NASA Astrophysics Data System (ADS)

Gamma radiation processing was found to extend shelf life of fresh turmeric. A 5 kGy radiation dose and 10 °C storage temperature was found to keep peeled turmeric samples microbe free and acceptable until 60 days of storage. The control sample without radiation treatment spoiled within a week of storage. The changes in color, texture and moisture content of fresh turmeric due to radiation treatment were found to be statistically insignificant.

Dhanya, R.; Mishra, B. B.; Khaleel, K. M.; Cheruth, Abdul Jaleel

2009-09-01

184

Radiative corrections to the Higgs boson decay rate $\\\\Gamma(H\\\\rightarrow ZZ)$ in the minimal supersymmetric model  

Microsoft Academic Search

We consider radiative corrections to the decay rate $\\\\Gamma(H\\\\rightarrow ZZ)$\\u000aof the heavy {\\\\it CP}-even Higgs boson of the minimal supersymmetric model to\\u000atwo $Z$ bosons. We perform a one loop Feynman diagram calculation in the\\u000aon-mass-shell renormalization scheme, and include the third generation of\\u000aquarks and squarks. The tree level rate is suppressed by a mixing angle factor\\u000aand

Damien Pierce; Aris Papadopoulos

1992-01-01

185

Health effects of low level radiation  

Microsoft Academic Search

Radiation is of many different types, almost all of which have been held to affect health in one way or another. However, it is the effects of ionizing radiation that have given rise to the most controversy and for which the need for assessment is most urgent. That there has been - and continues to be - much controversy about

R. Doll; S. Darby

1990-01-01

186

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

187

Pulsar and diffuse contributions to observed galactic gamma radiation  

NASA Technical Reports Server (NTRS)

The first calculation of a gamma-ray production spectrum from pulsars in the Galaxy, along with a statistical analysis of data on 328 known radio pulsars, are presented. The implications of this point source contribution to the general interpretation of the observed galactic gamma-ray spectrum are indicated. The contributions from diffuse interstellar cosmic-ray induced production mechanisms are then re-examined, concluding that pulsars may be contributing significantly to the galactic gamma-ray emission.

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

1981-01-01

188

Isotropic analogs for radiation levels across off-core midplane penetrations  

Microsoft Academic Search

This paper develops the isotropic analogs of fast neutron flux (energy > 1 MeV) and gamma dose rate at the core mid-plane and at a typical off-core midplane penetration, e.g., a recirculation line penetration. The authors use the basic methodology of evaluating radiation levels outside primary shield wall penetrations using isotropic analogs previously developed. The method developed and illustrated in

S. K. Bhatnagar; P. R. Allen

1990-01-01

189

Health aspects of low-level ionizing radiation  

Microsoft Academic Search

Biological effects of small multiples of the natural ionizing radiation environment are addressed and attention paid to potential public health problems in nuclear technology. Implications for the employment of radiation in the healing arts are discussed. Formidable mathematical obstacles are noted due to the fact that health effects at low-level radiation doses are generally inferred from observations at much larger

LEONARD R. SOLON

1987-01-01

190

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

191

Radiation and health: The biological effects of low-level exposure to ionizing radiation  

Microsoft Academic Search

This book contains 22 chapters. Some of the chapter titles are: Doses from environmental radioactivity; The role of predictive modelling: social and scientific problems of radiation risk assessment; Recent evidence of radiation-induced cancer in the Japanese atomic bomb survivors; Variation in individual sensitivity to ionizing radiation; Cancer incidence and background levels of radiation; Leukemia and nuclear power in Britain; and

R. R. Jones; R. Southwood

1987-01-01

192

Protection effects of condensed bromoacenaphthylene on radiation deterioration of ethylene-propylene-diene rubber. [Gamma radiation  

SciTech Connect

As a continuation of a series of the studies on the flame and ..gamma..-radiation resistant modification of ethylene-propylene-diene rubber (EPDM), condensed bromoacenaphthylene (con-BACN) as a newly developed flame retardant was synthesized and its effects on the radiation resistance of EPDM were investigated. The radiation resistance evaluated by measuring tensile properties of irradiated sheets of 2 mm thick was found improved greatly by adding con-BACN together with ordinary rubber ingredients but decreased by decabromodiphenylether (DBDPE) that has bromins in aromatic rings as con-BACN. When EPDM sheets of 1 mm thick were irradiated in oxygen at a dose rate of 1 X 10/sup 5/ rad/h, the weight swelling ratio increased with increasing dose, indicating that oxidative main chain scission is predominant under the irradiation conditions. On the other hand, crosslinking was shown to be predominant in nitrogen. From the results of the swelling experiments with different additives, it was concluded that DBDPE accelerates both the main chain scission in oxygen and the crosslinking in nitrogen. In contrast to this, con-BACN reduced the chain scission in oxygen. This observation was accounted by the assumption that the influence of the oxidative chain scission is partly compensated by the concurrent crosslinking which takes place through additions of con-BACN to substrate polymers even in the presence of oxygen.

Morita, Y.; Hagiwara, M.; Kasai, N.

1982-09-01

193

Radiation levels in the SSC experimental facilities  

SciTech Connect

Because of the increase in beam energy and intensity at the Superconducting Super Collider Laboratory (SSCL) accelerator, the biological shielding necessary for the experimental halls as well as the shielding for various detector components will require a much more critical review than that carried out for previous high energy physics facilities such as the Fermi National Accelerator Laboratory (FNAL) or the Stanford Linear Accelerator Center (SLAC). This paper summarizes studies of the neutron and gamma-ray doses that are anticipated in and around the Solenoidal Detector Collaboration (SDC) and the Gamma Electron Muon (GEM) experimental halls, the Beam Calibration (BC) hall, and a study of shield optimization for the muon chambers. The analysis for SDC and GEM halls included normal operation and accidental conditions.

Alsmiller, F.S.; Alsmiller, R.G. Jr.; Fu, C.Y.; Gabriel, T.A.; Lillie, R.A.; Slater, C.O.

1993-10-01

194

Radiative processes (tau -> mu gamma, mu -> e gamma and muon g-2) as probes of ESSM/SO(10)  

E-print Network

The Extended Supersymmetric Standard Model (ESSM), motivated on several grounds, introduces two vectorlike families (16 + 16-bar) of SO(10)) with masses of order one TeV. It is noted that the successful predictions of prior work on fermion masses and mixings, based on MSSM embedded in SO(10), can be retained rather simply within the ESSM extension. These include an understanding of the smallness of V_{cb} ~ 0.04 and the largeness of nu_mu - nu_tau oscillation angle, sin^2 2 theta_{nu_mu nu_tau}^{osc} ~ 1. We analyze the new contributions arising through the exchange of the vectorlike families of ESSM to radiative processes including tau -> mu gamma, mu -> e gamma, b -> s gamma, EDM of the muon and the muon (g-2). We show that ESSM makes significant contributions especially to the decays tau -> mu gamma and mu -> e gamma and simultaneously to muon (g-2). For a large and plausible range of relevant parameters, we obtain: a_mu^{ESSM} ~ +(10-40) times 10^{-10}, with a correlated prediction that tau -> mu gamma should be discovered with an improvement in its current limit by a factor of 3-20. The implications for mu -> e gamma are very similar. The muon EDM is within reach of the next generation experiments. Thus, ESSM with heavy leptons being lighter than about 700 GeV (say) can be probed effectively by radiative processes before a direct search for these vectorlike leptons and quarks is feasible at the LHC.

K. S. Babu; Jogesh C. Pati

2002-07-23

195

[Cytotoxicity of PVC tubes sterilized in ethylene oxide after gamma radiation exposure].  

PubMed

Do materials sterilized using gamma rays become toxic when re-sterilized in ethylene oxide? This question guided the objective of this study, which was to investigate the potential cytotoxic effect of PVC sterilized by gamma radiation and re-sterilized with EO by the agar diffusion method in cell cultures. Nine PVC tubes were subjected to gamma radiation sterilization and were re-sterilized in EO. The tubes were divided into a total of 81 units of analysis that were tested so as to represent the internal and external surfaces and mass of each tube. It was concluded that the PVC materials sterilized in gamma radiation and re-sterilized in EO are not cytotoxic. PMID:23743920

de Souza, Rafael Queiroz; Graziano, Kazuko Uchikawa; Ikeda, Tamiko Ichikawa; Gonçalves, Cláudia Regina; Cruz, Aurea Silveira

2013-04-01

196

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

197

Action Levels in Medical Treatment of Radiation and Radioactivity Exposure  

Microsoft Academic Search

Medical treatment of the worker accidentally overexposed to radiation is not an appropriate area for action levels. Special medical problems for which action levels might be considered include the handling of the pregnant employee who works in a radiation area, the handling of cases of skin and wound contamination, work restrictions on individuals with internal contamination, and the need for

T. A. Lincoln

1965-01-01

198

Low-level radiation effects: a fact book  

Microsoft Academic Search

Low Level Raidation Effects: A Fact Book, prepared by the Society of Nuclear Medicine Subcommittee on the Risks of Low-Level Ionizing Radiation, attempts to examine the health effects of small doses of radiation. For immediate questions, this work provides a well-organized brief summary of recent radiologic data from refereed scientific literature and from the publications of advisory groups such as

A. B. Brill; S. J. Adelstein; E. L. Saenger; E. W. Webster

1982-01-01

199

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

200

Terrestrial gamma radiation dose study to determine the baseline for environmental radiological health practices in Melaka state, Malaysia.  

PubMed

Environmental terrestrial gamma radiation dose rates were measured throughout Melaka, Malaysia, over a period of two years, with the objective of establishing baseline data on the background radiation level. Results obtained are shown in tabular, graphic and cartographic form. The values of terrestrial gamma radiation dose rate vary significantly over different soil types and for different underlying geological characteristics present in the study area. The values ranged from 54 +/- 5 to 378 +/- 38 nGy h(-1). The highest terrestrial gamma dose rates were measured over soil types of granitic origin and in areas with underlying geological characteristics of an acid intrusive (undifferentiated) type. An isodose map of terrestrial gamma dose rate in Melaka was drawn by using the GIS application 'Arc View'. This was based on data collected using a NaI(Tl) scintillation detector survey meter. The measurements were taken at 542 locations. Three small 'hot spots' were found where the dose rates were more than 350 nGy h(-1). The mean dose rates in the main population areas in the mukims (parishes) of Bukit Katil, Sungai Udang, Batu Berendam, Bukit Baru and Bandar Melaka were 154 +/- 15, 161 +/- 16, 160 +/- 16, 175 +/- 18 and 176 +/- 18 nGy h(-1), respectively. The population-weighted mean dose rate throughout Melaka state is 172 +/- 17 nGy h(-1). This is lower than the geographical mean dose rate of 183 +/- 54 nGy h(-1). The lower value arises from the fact that most of the population lives in the central area of the state where the lithology is dominated by sedimentary rocks consisting of shale, mudstone, phyllite, slate, hornfels, sandstone and schist of Devonian origin which have lower associated dose rates. The mean annual effective dose to the population from outdoor terrestrial gamma radiation was estimated to be 0.21 mSv. This value is higher than the world average of 0.07 mSv. PMID:16340071

Ramli, Ahmad Termizi; Sahrone, Sallehudin; Wagiran, Husin

2005-12-01

201

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

202

AMINO ACIDS IN COMETS AND METEORITES: STABILITY UNDER GAMMA RADIATION AND PRESERVATION OF THE  

E-print Network

AMINO ACIDS IN COMETS AND METEORITES: STABILITY UNDER GAMMA RADIATION AND PRESERVATION, Via Salaria Km 29,300, 00016 Monterotondo Stazione, Rome, Italy. 5 CSIC, Spain. Abstract Amino acids. We present laboratory studies testing the stability of amino acids against radiation photolysis. All

203

THE INFLUENCE OF $gamma$RADIATION AND NEUTRONS ON LACQUER COATINGS  

Microsoft Academic Search

An investigation was made of the influence of gamma radiation and of ; neutrons on protective coatings of various filmforming materials, such as ; chlorinated rubber, chlorinated polyvinyl chloride, polyvinyl butyral, copolymer ; of vinyl chloride and isobutyl ether or polyvinyl alcohol, alkyd resin, phenol-; formaldehyde resin and polymerized linseed oil. The radiation time was 3 mo ; (2,160 hr)

Z. Jedlinski; Z. Hippe; T. Uminski

1960-01-01

204

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

205

Preparation of cotton knitted fabric by gamma radiation: A new approach.  

PubMed

This study attempts to introduce the exploitation of gamma radiation for the processing of cotton knitted fabric. A systematic investigation into the situations suitable for eco-friendly preparation (scouring and bleaching) of cotton fabric was carried out. Fabric used in this experiment includes cotton knitted single jersey structure of 160gsm. The grey cotton knitted fabric was immersed in different (0 - 30g/L) amount of hydrogen peroxide solution for 10min. Subsequently, the samples were irradiated under Co-60 gamma radiation of absorbed dose (5-20kGy) at a dose rate 5kGy/h. Water absorbency, whiteness index (WI), weight loss, bursting strength, elongation at burst and dye uptake were taken as the measure of extent of scouring and bleaching performance of the intended fabric. The new technology yielded product with acceptable whiteness and water absorbency which is suitable for pale shade dyeing. The optimum results were achieved for the sample irradiated at a total dose 5kGy treated with 10g/L H2O2 solution. The water absorbency and WI value were 2.4s and 39.43, respectively, as well as 82.2% dye exhaustion was obtained having the bursting strength 203.20kPa for this option. But higher dose of radiation was found responsible for lowering the bursting strength of the fabric. However, the irradiated samples demonstrated the good dye-ability indicating the excellent level dyeing with Bezaktive Red S-3B and Novacron Yellow ST-3R reactive dyes. PMID:25662692

Bashar, M Mahbubul; Siddiquee, Md Abu Bakar; Khan, Mubarak A

2015-04-20

206

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

207

Mortality of the harvester ant (Pogonomyrmex owyheei) after exposure to /sup 137/Cs gamma radiation  

SciTech Connect

Harvester ants, Pogonomyrmex owyheei Cole, irradiated with 3.5 kR to 268 kR of /sup 137/Cs gamma radiation, were maintained at simulated summer (27/sup 0/C) and winter (7/sup 0/C) temperature regimes. After thirty days, the cool series was warmed to 27/sup 0/C and observed for mortality along with the warm series.Though mortality was delayed in the cool series, each series reached 50% mortality at similar rates. Because the harvester ant is extremely tolerant to radiation and experimental rates used far exceed possible environmental exposure, it is unlikely that ant colonies dwelling among low-level nuclear waste storage sites will be deleteriously affected by radiation. This species has the capability of tunneling to a depth well within the range of some buried waste. Since these harvester ants are potential transporters of buried waste, they should be considered as a biotic factor in radioactive waste management operations in semi-arid regions.

Gano, K.A.

1981-01-01

208

Mortality of the harvester ant (Pogonomyrmex owyheei) after exposure to /sup 137/Cs gamma radiation  

SciTech Connect

Harvester ants, Pogonomyrmex owyheei Cole, irradiated with 3.5 kR to 268 kR of /sup 137/Cs gamma radiation, were maintained at simulated summer (27/sup 0/C) and winter (7/sup 0/C) temperature regimes. After thirty days, the cool series was warmed to 27/sup 0/C and observed for mortality along with the warm series. Though mortality was delayed in the cool series, each series reached 50% mortality at similar rates. Because the harvester ant is extremely tolerant to radiation and experimental rates used far exceed possible environmental exposure, it is unlikely that ant colonies dwelling among low-level nuclear waste storage sites will be deleteriously affected by radiation. This species has the capability of tunneling to a depth well within the range of some buried waste. Since these harvester ants are potential transporters of buried waste, they should be considered as a biotic factor in radioactive waste management operations in semi-arid regions.

Gano, K.A.

1981-01-01

209

Recent results on celestial gamma radiation from SMM  

NASA Technical Reports Server (NTRS)

Observations made by the Gamma Ray Spectrometer on board the SMM are described. Recent results reported include observations and analyses of gamma-ray lines from Co-56 produced in supernovae, observations of the temporal variation of the 511 keV line observed during Galactic center transits, and measurements of the diffuse Galactic spectrum from 0.3 to 8.5 MeV. The work in progress includes measurements of the distribution of Galactic Al-26, observations to place limits on Galactic Ti-44 and Fe-60 and on Be-7 produced in novae, and searches for a characteristic gamma-ray emission from pair plasmas, a 2.223 MeV line emission, limits on deexcitation lines from interstellar C and O, and gamma-ray bursts.

Share, Gerald H.

1991-01-01

210

Gamma radiation effects on commercial Mexican bread making wheat flour  

Microsoft Academic Search

Gamma irradiation is considered to be an alternative method for food preservation to prevent food spoilage, insect infestation and capable of reducing the microbial load. In the present investigation, commercial Mexican bread making wheat flour was irradiated at 1.0kGy using a 60C Gammabeam 651 PT irradiator facility. No changes were detected in moisture, protein and ashes in gamma irradiated samples

Z. Agúndez-Arvizu; M. V. Fernández-Ramírez; M. E. Arce-Corrales; E. Cruz-Zaragoza; R. Meléndrez; V. Chernov; M. Barboza-Flores

2006-01-01

211

Minimizing the gamma radiation effects to spent fuel pool walls  

Microsoft Academic Search

This paper presents the study of the gamma exposure to the spent fuel pool walls from spent fuel assemblies. The Monte Carlo code, MCNP4C, was used to model and analyze the spent fuel pool walls. In addition, the gamma source from the spent fuel assembly was modeled by the isotope generation and depletion code, ORIGEN2.2. Both PWR (TMI-I) and BWR

Chanatip Tippayakul; Samuel Levine; Kostadin N. Ivanov; Moussa Mahgerefteh

2004-01-01

212

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

213

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

214

Astrophysical applications of Delbrück scattering: Dust scattered gamma radiation from gamma ray bursts  

NASA Astrophysics Data System (ADS)

A preliminary, and perhaps the first, study of astrophysical applications of Delbrück scattering in a gamma-ray emitting celestial object like a gamma-ray burst (GRB) has been made. At energies?100 MeV the elastic scattering of gamma-ray photons off the molecular dust surrounding the GRB site is dominated by Delbrück scattering. Expressions for Delbrück-scattered gamma-ray flux as a function of time has been obtained for a few selected energies by assuming a simple model of GRB. These are compared with Compton-scattered flux. At certain situations, interestingly, the former is found to exceed the latter for the first few milliseconds of the burst. The issue of detectability of Delbrück-scattered gamma-ray echo from the cloud of a GRB is discussed. Although it is observed that the detection of such an echo is not within the capability of the presently operating gamma-ray missions such as Fermi LAT, a rough estimate shows that one can be optimistic that future generation gamma-ray telescopes might be able to see such photons' contribution to the total flux.

Kunwar, B.; Bhadra, A.; Gupta, S. K. Sen

2014-02-01

215

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

216

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

217

Terrestrial Gamma-Ray Flashes, Relativistic Runaway, and High-Energy Radiation in the Atmosphere  

NASA Astrophysics Data System (ADS)

High energy radiation from tens of keV to tens of MeV in energy, the transition region from x-rays to gamma rays, has been observed in association with high electric fields in air in many contexts: from the ground, associated with thunderstorms and with individual flashes of natural and rocket-triggered lightning [1, 2, 3, 4, 5, 6, 7, 8] from sparks in the laboratory [9, 10, 11, 12], from Earth orbit in the form of millisecond Terrestrial Gamma-ray Flashes (TGFs) [13, 14], and at intermediate altitudes from aircraft and balloons [15, 16, 17, 18, 19]. The gamma radiation in all cases is almost certainly bremsstrahlung generated by the collision of accelerated electrons with nuclei in the atmosphere. The penetrating gamma-rays can provide a mechanism for coupling between the troposphere, mesosphere, ionosphere and magnetosphere in the form of energetic particles and ionization.

Smith, David M.

2009-04-01

218

Effects of low level radiation-what's new?  

PubMed

A comprehensive review of the effects of exposure to low levels of ionizing radiation, BEIR VII-Phase 2: Health Risks From Exposure to Low Levels of Ionizing Radiation, was published in 2006. The BEIR (Biological Effects of Ionizing Radiation) reports are a series of publications by the National Academy of Sciences. The last BEIR report on the effects of low level radiation, BEIR V, was published in 1990. To update the risk estimates for exposure to low levels of ionizing radiation, the BEIR committee reviewed recent epidemiologic studies of the atomic bomb survivors, as well as recent studies of populations exposed to radiation from diagnostic and therapeutic medical studies, from occupational exposures and from exposure due to releases of radioactive materials into the environment. Additional increasingly sophisticated epidemiologic studies continue to be published. BEIR VII reconfirmed that the linear no threshold model is the most practical model to estimate radiation risks, especially for radiation protection purposes. The updated risk estimates have not changed significantly from the BEIR V estimates, but the confidence intervals have narrowed as the result of the availability of additional data. The effects of low doses of radiation should be of particular interest to medical professionals because radiation exposure from diagnostic medical studies is, by far, the largest source of radiation exposure from human activity. One recommendation of the BEIR VII report is to perform epidemiologic studies of patients, especially children, who have been exposed to radiation as part of their care. A large, sophisticated epidemiologic study will likely be able to detect an increase in cancer risk. The purpose of this article is to highlight the contents of this important publication with particular emphasis on what is new. PMID:18662560

Royal, Henry D

2008-09-01

219

Protection of DNA and membrane from gamma radiation induced damage by gallic acid.  

PubMed

Gallic acid (3,4,5-trihydroxybenzoic acid, GA) is a naturally occurring plant phenol. In vitro and in vivo studies have shown that this phytochemical protected DNA and membranes against ionizing radiation. Rat liver microsomes and plasmid pBR322 DNA were exposed to various doses of gamma radiation in presence and absence of GA. Exposure of the microsomes to gamma radiation resulted in the formation of peroxides of membrane lipids measured as thiobarbituric acid reactive substances and presence of GA during irradiation prevented the formation of lipid peroxidation. Gamma irradiation of plasmid DNA resulted in induction of strand breaks in DNA resulting in disappearance of the supercoiled (ccc) form. Presence of GA during irradiation protected the DNA from undergoing the strand breaks. In in vivo studies it was found that whole body exposure of mice to gamma radiation (4 Gy) increased the formation of lipid peroxides in various tissues and damage to cellular DNA (as measured by alkaline comet assay) in peripheral blood leucocytes. Administration of GA to mice prior to whole body radiation exposure reduced the peroxidation of lipids and the damage to the cellular DNA indicating in vivo radiation protection of membranes and DNA by GA. PMID:16180096

Gandhi, Nitin Motilal; Nair, Cherupally Krishnan Krishnan

2005-10-01

220

High-energy gamma radiation from Geminga observed by EGRET  

NASA Technical Reports Server (NTRS)

The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) has carried out extensive studies of the gamma-ray source Geminga. Following the detection of pulsed X-rays (Halpern and Holt 1992) from Geminga, Bertsch et al. (1992) reported the same 237 ms periodicity to be visible in the EGRET data. A full analysis of the Geminga source shows that the energy spectrum is compatible with a power law with a spectral index of -1.50 +/- 0.08 between 30 MeV and 2 GeV. A falloff relative to the power law is observed for energies above 2 GeV. Phase-resolved spectra also show power laws with high-energy cutoffs, but with significant variation of the spectral index with phase. No unpulsed emission is observed. No evidence for time variation was found within the EGRET observations.

Mayer-Hasselwander, H. A.; Bertsch, D. L.; Brazier, K. T. S.; Chiang, J.; Fichtel, C. E.; Fierro, J. M.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.; Kwok, P. W.

1994-01-01

221

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body  

Microsoft Academic Search

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to

John E. Pattison; Richard P. Hugtenburg; Stuart Green

2010-01-01

222

Study on chemical, UV and gamma radiation-induced grafting of 2-hydroxyethyl methacrylate onto chitosan  

NASA Astrophysics Data System (ADS)

In the present study, 2-hydroxyethyl methacrylate has been grafted onto chitosan by using either chemical initiation, or photo-induction or gamma radiation-induced polymerisation, all under heterogeneous conditions. The evidence of grafting was provided by Fourier transform infrared spectroscopy and thermal analysis. The results concerning the effect of initiator concentration, initial monomer concentration and dose rate influencing on the yield of grafting reactions are presented. These suggest that gamma irradiation is the method that leads to higher yields of grafting.

Casimiro, M. H.; Botelho, M. L.; Leal, J. P.; Gil, M. H.

2005-04-01

223

Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level  

E-print Network

Time correlation of cosmic-ray-induced neutrons and gamma rays at sea level G. Miloshevsky n , A November 2013 Keywords: Cosmic rays Multiplicity Coincidence Correlation Poisson distribution Feynman-Y statistic a b s t r a c t The neutrons and gamma rays produced by cosmic ray interactions in spallation

Harilal, S. S.

224

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

225

Sensitivity of hyperthermia-treated human cells to killing by ultraviolet or gamma radiation  

SciTech Connect

Human xeroderma pigmentosum (XP) or Fanconi anemia (FA) fibroblasts displayed shouldered 45/sup 0/C heat survival curves not significantly different from normal fibroblasts, a result similar to that previously found for ataxia telangiectasia (AT) cells, indicating heat resistance is not linked to either uv or low-LET ionizing radiation resistance. Hyperthermia (45/sup 0/C) sensitized normal and XP fibroblasts to killing by gamma radiation but failed to sensitize the cells to the lethal effects of 254 nm uv radiation. Thermal inhibition of repair of ionizing radiation lesions but not uv-induced lesions appears to contribute synergistically to cell death. The thermal enhancement ratio (TER) for the synergistic interaction of hyperthermia (45/sup 0/C, 30 min) and gamma radiation was significantly lower in one FA and two strains (TER = 1.7-1.8) than that reported previously for three normal strains (TER = 2.5-3.0). These XP and FA strains may be more gamma sensitive than normal human fibroblasts. Since hyperthermia treatment only slightly increases the gamma-radiation sensitivity of ataxia telangiectasia (AT) fibroblasts compared to normal strains, it is possible that the degree of thermal enhancement attainable reflects the genetically inherent ionizing radiation repair capacity of the cells. The data indicate that both repair inhibition and particular lesion types are required for lethal synergism between heat and radiation. We therefore postulate that the transient thermal inhibition of repair results in the conversion of gamma-induced lesions to irrepairable lethal damage, while uv-type damage can remain unaltered during this period.

Mitchel, R.E.; Smith, B.P.; Wheatly, N.; Chan, A.; Child, S.; Paterson, M.C.

1985-11-01

226

Health Effects of Exposure to Low-Level Ionizing Radiation  

Microsoft Academic Search

This book is an easily readable text which, in seventeen chapters, covers far more subject matter than its title would suggest. It is the second edition of a text initially edited by W R Hendee in 1984 entitled `Health Effects of Low Level Radiation'. In producing this second edition, more information on the radiation physics principles, and the biology underlying

C Griffiths

1996-01-01

227

Application of whole-body personal TL dosemeters in mixed field beta-gamma radiation.  

PubMed

Application of whole-body personal TL dosemeters based on a high-sensitivity LiF:Mg,Cu,P (MCP-N) in mixed field beta-gamma radiation has been characterised. The measurements were carried out with (90)Sr/(90)Y, (85)Kr and (137)Cs point sources to calculate the energy response and linearity of the TLD response in a dose range of 0.1-30 mSv. From the result, calibration curves were obtained, enabling the readout of individual dose equivalent Hp(10) from gamma radiation and Hp(0.07) from beta radiation in mixed field beta-gamma. Limitation of the methodology and its application are presented and discussed. PMID:25009188

Ciupek, K; Aksamit, D; Wo?oszczuk, K

2014-11-01

228

Evaluation of three different optical fiber temperature sensor types for application in gamma radiation environments  

SciTech Connect

The authors compare the gamma radiation response of three different types of commercially available optical fiber temperature sensors. These are semiconductor absorption, Fabry-Perot cavity and fluorescence sensors. In order to evaluate their possible application in nuclear environments, they first highlight the principles of operation and the constructions. They then report on the gamma irradiation results and explain the observed degradation phenomena. For all three sensor types, the basic transduction mechanism does not seem to be affected by gamma radiation. The semiconductor absorption sensor shows a good radiation resistance (up to 160 kGy) in its present form, whereas the other sensor constructions need to be adapted. For the semiconductor absorption sensor, additional neutron irradiation experiments are performed, which are found to affect the principle of operation of this sensor.

Berghmans, F.; Vos, F.; Decreton, M. [SCK-CEN, Mol (Belgium). Belgian Nuclear Research Centre] [SCK-CEN, Mol (Belgium). Belgian Nuclear Research Centre

1998-06-01

229

Secondary production of neutral pi-mesons and the diffuse galactic gamma radiation  

NASA Technical Reports Server (NTRS)

Isobaric and scaling model predictions of the secondary spectra of neutral pi-mesons produced in proton-proton collisions, at energies between threshold and a few GeV, are compared on the basis of accelerator data and found to show the isobaric model to be superior. This model is accordingly used, in conjuction with a scaling model representation at high energies, in a recalculation of the pi exp (0) gamma-radiation's contribution to the diffuse galactic gamma background; the cosmic ray-induced production of photons (whose energy exceeds 100 MeV) by such radiation occurs at a rate of 1.53 x 10 to the -25 photons/(s-H atom). These results are compared with previous calculations of this process as well as with COS-B observations of the diffuse galactic gamma-radiation.

Dermer, C. D.

1986-01-01

230

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

231

Dipole analysis on EGRET data of extragalactic gamma ray background radiation  

NASA Technical Reports Server (NTRS)

A dipole analysis on the EGRET (Energetic Gamma-Ray Experimental Telescope) data seems to be one of the numerous subjects that can be investigated for the extragalactic gamma ray background radiation. By the end of the first one and half years after launch, the all-sky survey program of GRO (Gamma Ray Observatory) will be completed. The EGRET detector will cover the full sky area fairly well by that time. A set of gamma ray data suitable for dipole moment calculations will be available. Furthermore, there now exist in the literature several dipole anisotropy results calculated for optical and infrared observations on the distribution of galaxies in the full sky. The results of dipole moment analysis from gamma ray observation can be compared with those at other wavebands, and hopefully some deeper understanding can be gained on the large scale structure of the Universe.

Lin, Ying-Chi

1990-01-01

232

Lunar radiation environment: a study by using Kaguya gamma-ray spectrometer and Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

We have continued to improve the estimation of radiation dose on the Moon based on observation by remote sensing and calculation of the transportation of cosmic-ray particles in the lunar materials in order to provide basic data for a future manned lunar exploration. On the lunar surface, the dose of primary galactic cosmic rays (pGCR) is the most significant and the contributions of neutrons and gamma rays are relatively small and are approximately 10% and 1% of that of pGCR, respectively. However, these percentages are changed by use of thick shieldings and also geographical feature of the lunar surface, such as margin of a huge boulder, bottom of a pit, inside of a possible lava tube. In this case, the dose by pGCRs is moderated and the contributions of neutrons and gamma rays relatively increase. Here, we show the recent estimation of spatial variation of the lunar dose due to gamma ray and neutrons measured by Kaguya gamma-ray spectrometer. The energy spectrum of gamma rays from the lunar surface are precisely measured by a germanium (Ge) gamma-ray spectrometer onboard the Japanese lunar orbiter (Kaguya/SELENE). The flux of fast neutrons from the lunar surface was also measured by detecting the characteristic gamma rays due to the neutron inelastic reaction with the Ge of the spectrometer, that is 72Ge(n, n'g)72Ge. The estimation of radiation dose on the Moon based on Monte Carlo simulation will also be presented.

Kobayashi, Shingo; Hayatsu, Kanako; Uchihori, Yukio; Hareyama, Makoto; Hasebe, Nobuyuki; Fujibayashi, Yukari

2012-07-01

233

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

234

Production of hydrogel wound dressings using gamma radiation  

Microsoft Academic Search

Hydrogel wound dressings have been prepared using the gamma rays irradiation technique. The dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The influence of some process parameters on the properties of the dressings has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. The gel fraction increases with increasing PVP concentration due

Z. Ajji; I. Othman; J. M. Rosiak

2005-01-01

235

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

236

Effective gamma-ray doses due to natural radiation from soils of southeastern Brazil  

NASA Astrophysics Data System (ADS)

We have used gamma-ray spectrometry to study the distribution of natural radiation from soils of southeastern Brazil: Billings reservoir, Sa~o Bernardo do Campo Parks, Diadema Parks, Interlagos region, Sa~o Paulo, and soil from Sa~o Paulo and Rio de Janeiro beaches. In most of the regions studied we have found that the dose due the external exposure to gamma-rays, proceeding from natural terrestrial elements, are between the values 0.3 and 0.6 mSv/year, established by the United Nations Scientific Committee on the Effects of Atomic Radiation.

Silveira, M. A. G.; Medina, N. H.; Moreira, R. H.; Bellini, B. S.; Aguiar, V. A. P.

2010-08-01

237

A biotechnological project with a gamma radiation source of 100,000 Ci  

NASA Astrophysics Data System (ADS)

A project for the production of radiovaccines and other bio-medical products is presented which includes a radiation facility provided with a gamma ray source equivalent to 100,000 Ci of Co-60. The whole process incorporates novel basic features in virus production and inactivation steps. The former is carried out in animals previously subjected to immunodepression through electromagnetic radiation. The later is obtained at low temperatures by using either electromagnetic or particle radiations. A vaccine manufacture process is shown to illustrate the utilization of ionizing radiations to obtain a foot and mouth disease virus (FMDV) vaccine with good antigenic quality and low cost.

Lombardo, J. H.; Smolko, E. E.

238

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

239

Gamma radiation increases endonuclease-dependent L1 retrotransposition in a cultured cell assay.  

PubMed

Long Interspersed Elements (LINE-1s, L1s) are the most active mobile elements in the human genome and account for a significant fraction of its mass. The propagation of L1 in the human genome requires disruption and repair of DNA at the site of integration. As Barbara McClintock first hypothesized, genotoxic stress may contribute to the mobilization of transposable elements, and conversely, element mobility may contribute to genotoxic stress. We tested the ability of genotoxic agents to increase L1 retrotransposition in a cultured cell assay. We observed that cells exposed to gamma radiation exhibited increased levels of L1 retrotransposition. The L1 retrotransposition frequency was proportional to the number of phosphorylated H2AX foci, an indicator of genotoxic stress. To explore the role of the L1 endonuclease in this context, endonuclease-deficient tagged L1 constructs were produced and tested for their activity in irradiated cells. The activity of the endonuclease-deficient L1 was very low in irradiated cells, suggesting that most L1 insertions in irradiated cells still use the L1 endonuclease. Consistent with this interpretation, DNA sequences that flank L1 insertions in irradiated cells harbored target site duplications. These results suggest that increased L1 retrotransposition in irradiated cells is endonuclease dependent. The mobilization of L1 in irradiated cells potentially contributes to genomic instability and could be a driving force for secondary mutations in patients undergoing radiation therapy. PMID:16507671

Farkash, Evan A; Kao, Gary D; Horman, Shane R; Prak, Eline T Luning

2006-01-01

240

[Observation of Cherenkov Radiation from Aquarium Irradiated with Co-60 Gamma-rays  

PubMed

Cherenkov radiation in water at a nuclear power plant is caused by a nuclear fuel rod and is well known generally. If students can observe Cherenkov radiation at school easily, they can be impressed by the fascinating radiation. Moreover the observation may bring about interest in radiological physics profoundly. A few years ago, management of the Co-60 gamma-ray irradiation apparatus was transferred to Nagoya university school of health sciences from the related hospital. Therefore we have examined the system to observe the Cherenkov radiation in water from secondary electrons generated by Co-60 gamma-rays. At first, the Cherenkov radiation in the aquarium was led to the corridor outside the irradiation room using a mirror, and observed directly while avoiding exposure. Secondly photographs of the Cherenkov radiation from various angles were taken under conditions which consisted of several irradiation fields and pass lengths of gamma-rays in water, and were compared with each other. Our method for observing the Cherenkov radiation may be useful enough for students to raise their dedication in radiological physics study. PMID:12766306

Hibino, Sachiko; Tamiya, Tadashi; Koyama, Shuji; Homma, Mitsuhiko; Tabushi, Katsuyoshi; Obata, Yasunori

2001-01-01

241

900-MHz microwave radiation enhances gamma-ray adverse effects on SHG44 cells.  

PubMed

Mobile phones are widely used globally. However, the biological effects due to exposure to electromagnetic fields (EMF) produced by mobile phones are largely unknown. Environmental and occupational exposure of humans to gamma-rays is a biologically relevant phenomenon. Consequently studies were undertaken to examine the interactions between gamma-rays and EMF on human health. In this study, exposure to 900-MHz EMF expanded gamma-ray damage to SHG44 cells. Preexposure EMF enhanced the decrease in cell proliferation induced by gamma-ray irradiation and the rate of apoptosis. The combination of EMF and gamma-ray exposure resulted in a synergistic effect by triggering stress response, which increased reactive oxygen species, but the expression of hsp70 at both mRNA and protein levels remained unaltered. Data indicate that the adverse effects of gamma-rays on cellular functions are strengthened by EMF. PMID:19492235

Cao, Yi; Zhang, Wei; Lu, Min-Xia; Xu, Qian; Meng, Qian-Qian; Nie, Ji-Hua; Tong, Jian

2009-01-01

242

Microbiological, chemical, and sensory quality changes in Pico de gallo as affected by gamma radiation  

E-print Network

by radiation and storage. Pectin solubility was affected by radiation treatment and storage. Radiation resulted in conversion of CSP to NXP. Levels of WSP and NXP increased in both treatments during storage, while levels of CSP and OHSP decreased. Pectins were...

Miller, Gerald Howard

2012-06-07

243

Examining a link between SPEs and ground level radiation  

NASA Astrophysics Data System (ADS)

Researchers have previously found a correlation between solar proton events (SPEs) and congenital malformations (CMs). A similar correlation has also been found between long term solar variability and CMs. We examine the ionizing radiation dose from these events as well as the largest events on record to determine whether these events are capable of producing these effects. We show that the total ionizing radiation dose (consisting of neutrons and muons) at ground level is insufficient for production of the observed increases in CM rate under the current paradigm regarding ionizing radiation from muons and neutrons. Current research on the subject shows that our assumptions regarding muonic ionizing radiation may be underestimating their biologic effect. We recommend further experimentation regarding the radiation dose due to muons, as this may prove to be a more substantial contribution to our radiation environment than previously assumed.

Overholt, Andrew

2015-01-01

244

Immunotherapy of acute radiation syndromes with antiradiation gamma G globulin.  

NASA Astrophysics Data System (ADS)

Introduction: If an immunotherapy treatment approach to treatment of acute radiation syndromes (ARS) were to be developed; consideration could be given to neutralization of radiation toxins (Specific Radiation Determinants- SRD) by specific antiradiation antibodies. To accomplish this objective, irradiated animals were injected with a preparation of antiradiation immunoglobulin G (IgG) obtained from hyperimmune donors. Radiation-indeced toxins that we call Specific Radiation Determinants (SRD) possess toxic (neurotoxic, haemotoxic and enterotoxic) characteristics as well as specific antigenic properties that combined with the direct physiochemical direct radiation damage, induce the development of many of the pathological processes associated with ARS. We tested several specific hyperimmune IgG preparations against these radiation toxins and observed that their toxic properties were neutralized by specific antiradiation IgGs. Material and Methods: Rabbits were inoculated with SRD radiation toxins to induce hyperimmune serum. The hyperimmune serum was pooled from several animals, purified, and concentrated. Enzyme-linked immunosorbent assays of the hyperimmune serum revealed high titers of IgG with specific binding to radiation toxins. The antiradiation IgG preparation was injected into laboratory animals one hour before and three hours after irradiation, and was evaluated for its ability to protect inoculated animals against the development of acute radiation syndromes. Results: Animals that were inoculated with specific antiradiation antibodies before receiving lethal irradiation at LD 100/30 exhibited 60-75% survival rate at 30 days, whereas all control animals expired by 30 days following exposure. These inoculated animals also exhibited markedly reduced clinical symptoms of ARS, even those that did not survive irradiation. Discussion: The results of our experiments demonstrate that rabbit hyperimmune serum directed against SRD toxins afford significant, albeit incomplete, protection against high doses of radiation. In comparison, the mortality rate of irradiated control animals was 100% in the same time period. The mortality rates of hyperimmune serum-treated animals varied in different groups of animals and different forms of ARS; however, significant radioprotection was observed in each group treated with IgGs activated against specific radiation toxins.

Popov, Dmitri; Maliev, Vecheslav; Casey, Rachael; Jones, Jeffrey; Kedar, Prasad

245

Stability of a salicylate-based poly(anhydride-ester) to electron beam and gamma radiation  

PubMed Central

The effect of electron beam and gamma radiation on the physicochemical properties of a salicylate-based poly(anhydride-ester) was studied by exposing polymers to 0 (control), 25 and 50 kGy. After radiation exposure, salicylic acid release in vitro was monitored to assess any changes in drug release profiles. Molecular weight, glass transition temperature and decomposition temperature were evaluated for polymer chain scission and/or crosslinking as well as changes in thermal properties. Proton nuclear magnetic resonance and infrared spectroscopies were also used to determine polymer degradation and/or chain scission. In vitro cell studies were performed to identify cytocompatibility following radiation exposure. These studies demonstrate that the physicochemical properties of the polymer are not substantially affected by exposure to electron beam and gamma radiation. PMID:21909173

Rosario-Meléndez, Roselin; Lavelle, Linda; Bodnar, Stanko; Halperin, Frederick; Harper, Ike; Griffin, Jeremy; Uhrich, Kathryn E.

2011-01-01

246

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

247

Irradiation tests of critical components for remote handling in gamma radiation environment  

NASA Astrophysics Data System (ADS)

Since the fusion power core of a D-T fusion reactor will be highly activated once it starts operation, personnel access will be prohibited so that assembly and maintenance of the components in the reactor core will have to be totally conducted by remote handling technology. Fusion experimental reactors such as ITER require unprecedented remote handling equipments which are tolerable under gamma radiation of more than 10(exp 6) R/h. For this purpose, the Japan Atomic Energy Research Institute (JAERI) has been developing radiation hard components for remote handling purpose and a number of key components have been tested over 10(exp 9) rad at a radiation dose rate of around 10(exp 6) R/h, using Gamma Ray Radiation Test Facility in JAERI-Takasaki Establishment. This report summarizes the irradiation test results and the latest status of AC servo motor, potentiometer, optical elements, lubricant, sensors and cables, which are key elements of the remote handling system.

Obara, Henjiro; Kakudate, Satoshi; Oka, Kiyoshi; Furuya, Kazuyuki; Taguchi, Kou; Tada, Eisuke; Shibanuma, Kiyoshi; Ohkawa, Yoshinao; Morita, Yousuke; Yokoo, Noriko

1994-08-01

248

Radiation detection system for portable gamma-ray spectroscopy  

DOEpatents

A portable gamma ray detection apparatus having a gamma ray detector encapsulated by a compact isolation structure having at least two volumetrically-nested enclosures where at least one is a thermal shield. The enclosures are suspension-mounted to each other to successively encapsulate the detector without structural penetrations through the thermal shields. A low power cooler is also provided capable of cooling the detector to cryogenic temperatures without consuming cryogens, due to the heat load reduction by the isolation structure and the reduction in the power requirements of the cooler. The apparatus also includes a lightweight portable power source for supplying power to the apparatus, including to the cooler and the processing means, and reducing the weight of the apparatus to enable handheld operation or toting on a user's person.

Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

2006-06-20

249

Effect of /sup 60/Co /gamma/-radiation on aqueous solutions of acrylamide  

SciTech Connect

Data were obtained on the dependence of the index of refraction (ir) of aqueous solutions of acrylamide on the absorbed dose of /sup 60/Co /gamma/-radiation. The calculated data on the dependence of ir on the degree of polymerization are reported. Using calculations of polymer models and the IR spectra, it was shown that the increase in the ir of the irradiated solution is due to oxidative processes which take place in the polymer formed under the effect of the radiation.

Zhestkova, T.P.; Misevich, B.S.; Kotov, A.V.

1988-07-01

250

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

251

Assessment of external gamma exposure and radon levels in a dwelling constructed with phosphogypsum plates.  

PubMed

Phosphogypsum, a fertilizer industry by-product, is being worldwide stockpiled, posing environmental concerns. Since this material contains natural radionuclides in significant concentrations, its use as a building material has radiological implications. In order to confirm the feasibility of the use of a new material mainly composed by phosphogypsum, an experimental house was built, having some of its rooms entirely lined with this material. Measurements of samples of phosphogypsum plates from different origins resulted in values of 0.2 to 2.6 for the external radiation index, thus justifying a more detailed investigation. In this paper, the application of a previously developed computational model to forecast external doses indoors is described. A comprehensive radiological evaluation is being performed, including measurement of the external gamma exposure and radon concentrations in one of the rooms of the house. The results show that the annual increment in the effective dose to an inhabitant of the house will remain below the 1 mSv limit for every reasonable scenario. The radon measurements were carried out over a period of 18 months, in order to determine the long-term average levels of the indoor radon concentrations. The results obtained are below 200 Bq m(-3), the recommended investigation level for radon. PMID:21458158

Máduar, M F; Campos, M P; Mazzilli, B P; Villaverde, F L

2011-06-15

252

Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation  

NASA Astrophysics Data System (ADS)

Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin-papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77±455.61 g/m2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

Singh, Durgeshwer; Singh, Rita

2012-11-01

253

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

Microsoft Academic Search

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

Ritenour

1986-01-01

254

Search for hadronic decays of a light Higgs boson in the radiative decay Upsilon --> gamma A0  

E-print Network

We search for hadronic decays of a light Higgs boson (A0) produced in radiative decays of an Upsilon(2S) or Upsilon(3S) meson, Upsilon --> gamma A0. The data have been recorded by the BABAR experiment at the Upsilon(3S) and Upsilon(2S) center of mass energies, and include (121.3 \\pm 1.2) x 10^6 Upsilon(3S) and (98.3 \\pm 0.9) x 10^6 Upsilon(2S) mesons. No significant signal is observed. We set 90% confidence level upper limits on the product branching fractions B(Upsilon(nS)-->gamma A0) x B(A0-->hadrons) (n=2 or 3) that range from 1 x 10^{-6} for an A0 mass of 0.3 GeV/c^2 to 8 x 10^{-5} at 7 GeV/c^2.

Lees, J P; Tisserand, V; Tico, J Garra; Grauges, E; Martinelli, M; Milanes, D A; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Brown, D N; Kerth, L T; Kolomensky, Yu G; Lynch, G; Koch, H; Schroeder, T; Asgeirsson, D J; Hearty, C; Mattison, T S; McKenna, J A; So, R Y; Khan, A; Blinov, V E; Buzykaev, A R; Druzhinin, V P; Golubev, V B; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Yushkov, A N; Bondioli, M; Kirkby, D; Lankford, A J; Mandelkern, M; Stoker, D P; Atmacan, H; Gary, J W; Liu, F; Long, O; Vitug, G M; Campagnari, C; Hong, T M; Kovalskyi, D; Richman, J D; West, C A; Eisner, A M; Kroseberg, J; Lockman, W S; Martinez, A J; Schalk, T; Schumm, B A; Seiden, A; Cheng, C H; Doll, D A; Echenard, B; Flood, K T; Hitlin, D G; Ongmongkolkul, P; Porter, F C; Rakitin, A Y; Andreassen, R; Dubrovin, M S; Huard, Z; Meadows, B T; Sokoloff, M D; Sun, L; Bloom, P C; Ford, W T; Gaz, A; Nagel, M; Nauenberg, U; Smith, J G; Wagner, S R; Ayad, R; Toki, W H; Spaan, B; Kobel, M J; Schubert, K R; Schwierz, R; Bernard, D; Verderi, M; Clark, P J; Playfer, S; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Fioravanti, E; Garzia, I; Luppi, E; Munerato, M; Negrini, M; Piemontese, L; Santoro, V; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Nicolaci, M; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Contri, R; Guido, E; Vetere, M Lo; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Bhuyan, B; Prasad, V; Lee, C L; Morii, M; Edwards, A J; Adametz, A; Marks, J; Uwer, U; Bernlochner, F U; Ebert, M; Lacker, H M; Lueck, T; Dauncey, P D; Tibbetts, M; Behera, P K; Mallik, U; Chen, C; Cochran, J; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Guo, Z J; Arnaud, N; Davier, M; Grosdidier, G; Diberder, F Le; Lutz, A M; Malaescu, B; Roudeau, P; Schune, M H; Stocchi, A; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Chavez, C A; Coleman, J P; Fry, J R; Gabathuler, E; Hutchcroft, D E; Payne, D J; Touramanis, C; Bevan, A J; Di Lodovico, F; Sacco, R; Sigamani, M; Cowan, G; Brown, D N; Davis, C L; Denig, A G; Fritsch, M; Gradl, W; Hafner, A; Prencipe, E; Alwyn, K E; Bailey, D; Barlow, R J; Jackson, G; Lafferty, G D; Behn, E; Cenci, R; Hamilton, B; Jawahery, A; Roberts, D A; Simi, G; Dallapiccola, C; Cowan, R; Dujmic, D; Sciolla, G; Lindemann, D; Patel, P M; Robertson, S H; Schram, M; Biassoni, P; Lazzaro, A; Lombardo, V; Neri, N; Palombo, F; Stracka, S; Cremaldi, L; Godang, R; Kroeger, R; Sonnek, P; Summers, D J; Nguyen, X; Taras, P; De Nardo, G; Monorchio, D; Onorato, G; Sciacca, C; Raven, G; Snoek, H L; Jessop, C P; Knoepfel, K J; LoSecco, J M; Wang, W F; Honscheid, K; Kass, R; Brau, J; Frey, R; Sinev, N B; Strom, D; Torrence, E; Feltresi, E; Gagliardi, N; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Akar, S; Ben-Haim, E; Bomben, M; Bonneaud, G R; Briand, H; Calderini, G; Chauveau, J; Hamon, O; Leruste, Ph; Marchiori, G; Ocariz, J; Sitt, S; Biasini, M; Manoni, E; Pacetti, S; Rossi, A; Angelini, C; Batignani, G; Bettarini, S; Carpinelli, M; Casarosa, G; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Oberhof, B; Paoloni, E; Perez, A; Rizzo, G; Walsh, J J; Pegna, D Lopes; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Anulli, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Piredda, G; Bünger, C; Grünberg, O; Hartmann, T; Leddig, T; Schröder, H; Waldi, R; Adye, T; Olaiya, E O; Wilson, F F; Emery, S; de Monchenault, G Hamel; Vasseur, G; Yeche, Ch; Aston, D; Bard, D J; Bartoldus, R; Cartaro, C; Convery, M R; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Sevilla, M Franco; Fulsom, B G; Gabareen, A M; Graham, M T; Grenier, P; Hast, C; Innes, W R; Kelsey, M H; Kim, H; Kim, P; Kocian, M L; Leith, D W G S; Lewis, P; Li, S; Lindquist, B; Luitz, S; Luth, V; Lynch, H L; MacFarlane, D B; Muller, D R; Neal, H; Nelson, S; Ofte, I; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Snyder, A; Su, D; Sullivan, M K; Va'vra, J; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Wulsin, H W; Yarritu, A K; Young, C C; Ziegler, V; Park, W; Purohit, M V; White, R M; Wilson, J R; Randle-Conde, A; Sekula, S J; Bellis, M; Benitez, J F; Burchat, P R; Miyashita, T S; Alam, M S; Ernst, J A; Gorodeisky, R; Guttman, N; Peimer, D R; Soffer, A; Lund, P; Spanier, S M; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Wray, B C; Izen, J M; Lou, X C; Bianchi, F; Gamba, D; Lanceri, L; Vitale, L; Martinez-Vidal, F; Oyanguren, A; Ahmed, H; Albert, J; Banerjee, Sw; Choi, H H F; King, G J; Kowalewski, R; Lewczuk, M J; Nugent, I M; Roney, J M; Sobie, R J; Tasneem, N; Gershon, T J; Harrison, P F; Latham, T E; Puccio, E M T; Band, H R; Dasu, S; Pan, Y; Prepost, R; Wu, S L

2011-01-01

255

Can gamma radiation be produced in the electrical environment above thunderstorms?  

Microsoft Academic Search

Calculations indicate that regions above large mesocsale convective systems may be favorable electrical environments for the production of gamma radiation by runaway electrons in bremsstrahlung collisions. It is well known (Gurevich, 1961) that an electric field however small can accelerate an electron continuously until the electric field is larger than the oppposing force of friction. Since the force of friction

Britton Chang; Colin Price

1995-01-01

256

Study of influence on harvesting point in Brazilian Tommy Atkins mangoes submitted to gamma radiation  

Microsoft Academic Search

Brazil is a great producer of tropical fruits including mangoes. Among several purposes gamma radiation can be applied as phytosanitary treatment. This is well studied in scientific papers and more recently demonstrated through commercial advances like bilateral protocols established between India and USA. The whole experiment evolved two parts where each of them used fruits from different maturity stages (stages

S. F. Sabato; J. N. Cruz; P. R. Rela; P. O. Broisler

2009-01-01

257

Inactivation of foodborne pathogens on crawfish tail meat using cryogenic freezing and gamma radiation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foodborne illness outbreaks occasionally occur as a result of microbiologically contaminated crustaceans, including crawfish. Cryogenic freezing and gamma radiation are two technologies which can be used to improve the microbiological safety and shelf-life of foods. In the U.S. the majority of non-c...

258

Radiation degradation and frictional properties of gamma sterilized PVC (copper-T)  

NASA Astrophysics Data System (ADS)

Polyvinyl chloride (PVC) components used in medical devices as flanges may lose their frictional property on gamma sterilization due to radiation degradation. Frictional load, glass transition temperature, linear expansion coefficient, dynamic load expansion and specific heat measurements have been carried out on PVC flanges to investigate the effect of irradiation and formulations have been developed for eliminating the undesired effects.

Varshney, L.; Balan, N.; Choughule, S. V.; Jothish, P. K.; Krishnamurthy, K.

1996-04-01

259

Advanced radiation imaging of low-intensity gamma-ray sources  

NASA Astrophysics Data System (ADS)

Imaging gamma-ray sources and distributions of low intensity is difficult using current commercially available radiation imagers. Radiation Monitoring Devices, Inc. has carried out the research and development necessary to construct a novel, compact radiation-imaging device, RADCAM, for low-intensity applications. The device consists of a position-sensitive photomultiplier tube (PSPMT) coupled to a CsI(Na) scintillation crystal, which is an excellent candidate for such applications due to its high light output. A tungsten coded-aperture mask, placed in front of the scintillator, creates a gamma-ray intensity pattern across the face of the crystal. The PSPMT detects the resulting scintillation pattern and the analog output signals are captured and converted to digital signals by the RMD PSPMT interface card. The digital data is stored and processed by a portable personal computer. The gamma-ray "shadowgram" is then mathematically decoded to yield the original source image. The pseudo-color radiation-source image is overlaid on a video picture of the same area captured by a high-resolution CCD. The combined image is displayed on screen as an accurate map of radioactive gamma-ray sources in the physical environment. Data acquisition and image display are controlled by the IMager Acquisition and Graphical-user-interface Environment (IMAGE), a Windows-NT program developed for the imager.

Woodring, M.; Souza, D.; Tipnis, S.; Waer, P.; Squillante, M.; Entine, G.; Ziock, K. P.

1999-02-01

260

PROTECTION AGAINST THE GAMMA RADIATION OF THE RADIOACTIVE FALL-OUT IN ATOMIC BOMB EXPLOSIONS  

Microsoft Academic Search

The present study is bansd on the information which has been revealed ; concerning the extent of contamination in the fall-out area of a 15 megaton ; hydrogen bomb (Bikini test, March 1, 1954). On the basis of these data the ; protection afforded by bunkers and house cellars against the gamma radiation of ; fall-out is estimated. In addition,

Rudloff

1958-01-01

261

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...

262

Gamma radiation inactivation of non-0157:H7 shiga-toxin producing Escherichia coli in foods  

Technology Transfer Automated Retrieval System (TEKTRAN)

Non-O157:H7 serovars of shiga-toxin producing Escherichia coli are emerging foodborne pathogens that have been associated with illness outbreaks and food product recalls on a global basis. Ionizing (gamma) radiation is a nonthermal food safety intervention technology that has been approved for use i...

263

Radiation inactivation of human gamma-interferon: cellular activation requires two dimers.  

PubMed Central

gamma-Interferon (IFN-gamma) is a 17-kDa broad-spectrum cytokine which exerts its effects on a variety of target cells through its interaction with the IFN-gamma receptor. Although physicochemical studies of Escherichia coli-derived IFN-gamma, as well as its crystal structure, demonstrate that it is a homodimer in solution (M(r) 34,000), previous radiation inactivation studies yielded a functional size for IFN-gamma of 63-73 kDa in an antiviral assay. To understand the relationship between the solution form of IFN-gamma and the moiety that actually binds to the cellular receptor and activates cells, we examined irradiated nonradioactive and 32P-labeled IFN-gamma for its migration in SDS/polyacrylamide gels (to determine its physical integrity), its binding to cells, its reactivity in an ELISA, and its antiviral activity. The functional size of IFN-gamma differed in the assays, being 22 +/- 2 kDa for the physical destruction of IFN-gamma, 56 +/- 2 kDa for the cellular binding assay, 45-50 kDa for reactivity in the ELISA, and 72 +/- 6 kDa for antiviral activity. The results from the binding assays constitute direct evidence that IFN-gamma binds to its cellular receptor as a dimer. However, for antiviral activity, the functional mass is equivalent to a tetramer. This is consistent with models involving ligand-induced receptor dimerization, whereby two dimers acting in concert (equivalent to the target size of a tetramer) are required to activate cells in the antiviral assay. Images PMID:8016072

Langer, J A; Rashidbaigi, A; Garotta, G; Kempner, E

1994-01-01

264

Production of hydrogel wound dressings using gamma radiation  

NASA Astrophysics Data System (ADS)

Hydrogel wound dressings have been prepared using the gamma rays irradiation technique. The dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The influence of some process parameters on the properties of the dressings has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. The gel fraction increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. The prepared hydrogels dressings could be considered as a good barrier against microbes.

Ajji, Z.; Othman, I.; Rosiak, J. M.

2005-04-01

265

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

266

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

267

Effect of gamma radiation on gelation in polyvinyl alcohol solutions  

NASA Astrophysics Data System (ADS)

The radiation effect of various pH values on polyvinyl alcohol aqueous solutions and on organic solutions, as well as those of scavengers in the aqueous solutions were examined. The gelation dose R g changes with various pH values; a small amount of free radical scavengers in the system inhibits the crosslinking of polymer molecules and raises R g. Degradation of polyvinyl in alcohol dimethyl sulfone solution occurs after irradiation, providing a mechanism of radiation-induced crosslinking of polyvinyl alcohol aqueous solutions is initiated by the transient species H and OH of water, but not the species e -aq.

Wenxiu, Chen; Huaying, Bao; Manwei, Zhang

268

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

269

Energy levels and radiative rates for transitions in Ti VII  

NASA Astrophysics Data System (ADS)

We report calculations of energy levels, radiative rates, oscillator strengths and line strengths for transitions among the lowest 231 levels of Ti VII. The general-purpose relativistic atomic structure package and flexible atomic code are adopted for the calculations. Radiative rates, oscillator strengths and line strengths are provided for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and magnetic quadrupole (M2) transitions among the 231 levels, although calculations have been performed for a much larger number of levels (159?162). In addition, lifetimes for all 231 levels are listed. Comparisons are made with existing results and the accuracy of the data is assessed. In particular, the most recent calculations reported by Singh et al (2012 Can. J. Phys. 90 833) are found to be unreliable, with discrepancies for energy levels of up to 1 Ryd and for radiative rates of up to five orders of magnitude for several transitions, particularly the weaker ones. Based on several comparisons among a variety of calculations with two independent codes, as well as with the earlier results, our listed energy levels are estimated to be accurate to better than 1% (within 0.1 Ryd), whereas results for radiative rates and other related parameters should be accurate to better than 20%.

Aggarwal, Kanti M.; Keenan, Francis P.

2013-12-01

270

Epidermal peroxisome proliferator-activated receptor gamma as a target for ultraviolet B radiation.  

PubMed

Ultraviolet B radiation (UVB) is a pro-oxidative stressor with profound effects on skin in part through its ability to stimulate cytokine production. Peroxisome proliferator-activated receptor gamma (PPAR gamma) has been shown to regulate inflammatory processes and cytokine release in various cell types. Since the oxidized glycerophospholipid 1-hexadecyl-2-azelaoyl glycerophosphocholine (azPC) has been shown to be a potent PPAR gamma agonist, this study was designed to assess whether the PPAR gamma system is a target for UVB irradiation and involved in UVB-induced inflammation in epidermal cells. The present studies demonstrated the presence of PPAR gamma mRNA and functional protein in human keratinocytes and epithelial cell lines HaCaT, KB, and A431. The treatment of epidermal cells with the PPAR gamma-specific agonist ciglitazone or azPC augmented cyclooxygenase-2 expression and enzyme activity induced by phorbol 12-myristate-13-acetate or interleukin-1 beta. Lipid extracts from the cell homogenate of UVB-irradiated, but not control, cells contained a PPAR gamma-agonistic activity identified by reporter assay, and this activity up-regulated cyclooxygenase-2 expression induced by phorbol 12-myristate-13-acetate. Subjecting purified 1-hexadecyl-2-arachidonoyl-glycerophosphocholine to UVB irradiation generated a PPAR gamma-agonistic activity, among which the specific PPAR gamma agonist azPC was identified by mass spectrometry. These findings suggested that UVB-generated PPAR gamma-agonistic activity was due to the free radical mediated non-enzymatic cleavage of endogenous glycerophosphocholines. Treatment with the specific PPAR gamma antagonist GW9662 or expression of a dominant-negative PPAR gamma mutant in KB cells inhibited UVB-induced epidermal cell prostaglandin E(2) production. These findings suggested that UVB-generated PPAR gamma activity is necessary for the optimal production of epidermal prostaglandins. These studies demonstrated that epithelial cells contain a functional PPAR gamma system, and this system is a target for UVB through the production of novel oxidatively modified endogenous phospholipids. PMID:15516334

Zhang, Qiwei; Southall, Michael D; Mezsick, Steven M; Johnson, Christopher; Murphy, Robert C; Konger, Raymond L; Travers, Jeffrey B

2005-01-01

271

Assessing Antibody Microarray for Space Missions: Effect of Long-term Storage, Gamma radiation and High Energy proton radiation  

NASA Astrophysics Data System (ADS)

Fluorescent antibody microarray has been proposed for Molecular biomarker detector in planetary exploration [1]. A number of different environmental stresses may affect the antibody performance, such as temperatures variations, highly penetrating radiation and high energy particles. Here we have tested the effect of gamma radiation, proton radiation and longterm storage on the microarray immunoassay and fluorocromes. Although different antibodies might have different susceptibilities we conclude that there was not significant reduction in the functionality of antibodies printed on the microarray and the fluorescent tracers antibodies, even in a extreme case of receiving a radiation dose 3000-fold than a biochip would receive in a trip mission to Mars. In summary, antibodies are suitable for use in planetary exploration purposes.

de Diego-Castilla, G.; Parro, V.

2012-09-01

272

Inactivation of foodborne pathogens on seafood by gamma radiation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ionizing radiation is used on a global basis to improve the phytosanitary and microbial safety and shelf-life of foods. In recent years progress has been made in the commercial application of irradiation to sterilize destructive invasive insects and to irradiate produce to improve its microbiologica...

273

Carbon Fibre Composite Materials Produced by Gamma Radiation Induced Curing of Epoxy Resins  

NASA Astrophysics Data System (ADS)

It is well known that ionizing radiation can initiate polymerization of suitable monomers for many applications. In this work an epoxy difunctional monomer has been used as matrix of a carbon fibre composite in order to produce materials through gamma radiation, for aerospace and advanced automotive applications. Radiation curing has been performed at different absorbed doses and, as comparison, also thermal curing of the same monomer formulations has been done. Furthermore some irradiated samples have been also subjected to a post irradiation thermal curing in order to complete the polymerization reactions. The properties of the cured materials have been studied by moisture absorption isotherms, dynamic mechanical thermal analysis and mechanical flexural tests.

Dispenza, C.; Alessi, S.; Spadaro, G.

2008-08-01

274

Effect of 60Co-gamma radiation on the binding properties in furs  

NASA Astrophysics Data System (ADS)

New Zealand white rabbit pelts were pickled by the usual procedure and were tanned with basic aluminium sulphate, basic chromium sulphate and their combinations. Tanned furs were irradiated with 60Co-gamma radiations in the dose range of 5.0-114.0 kGy. The effect of radiation on the binding properties of various added substances like mineral tannins, fats, moisture and shrinkage temperature has been assessed by their comparison with the control samples. The results of these investigations show that radiation on furs causes detannage, increases the moisture and bound fat content and decreases the shrinkage temperature of the furs.

Raina, R. K.

275

Interferon-gamma elevates nicotinamide N-methyltransferase activity and nicotinamide level in human glioma cells.  

PubMed

Nicotinamide N-methyltransferase (NNMT) catalyzes the N-methylation of nicotinamide. NNMT is strongly expressed in tumor cells and an increase in NNMT activity may reduce cellular nicotinamide level and thereby promote cell survival in the cells. However, there has been no report of a relationship between NNMT activity and nicotinamide level in tumor cells. We report herein that human glioma cells produce relatively large amounts of NNMT and that when these cells are cultured in the presence of interferon-gamma (IFN-gamma) their 1-methylnicotinamide levels increase. To clarify the mechanisms by which IFN-gamma increases 1-methylnicotinamide levels in these cells, we measured NNMT activity and the levels of NNMT expression, nicotinamide and nicotinamide adenine dinucleotide (NAD(+)) in the presence and absence of IFN-gamma. We also examined whether addition of exogenous 1-methylnicotinamide directly affects cell viability and/or the cellular levels of 1-methylnicotinamide, nicotinamide and NAD(+). While addition of 1-methylnicotinamide increased the total amount of cellular 1-methylnicotinamide present, it did not affect nicotinamide or NAD(+) levels, or cell viability. Conversely, IFN-gamma significantly increased NNMT activity and the nicotinamide cellular concentration, while leaving NNMT expression and the NAD(+) cellular concentration unchanged. Therefore, the increase in the 1-methylnicotinamide level found when IFN-gamma is present in culture may be a consequence of increases in both the nicotinamide concentration and NNMT activity, whereas, 1-methylnicotinamide did not influence nicotinamide levels, NAD(+) levels, or cell viability per se. These results suggest that an increase in NNMT activity does not always reduce cellular nicotinamide concentration in tumor cells. PMID:20495288

Yamada, Kazuo; Miyazaki, Takeshi; Hara, Nobumasa; Tsuchiya, Mikako

2010-01-01

276

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

277

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

278

Evaluation of phenolic compounds in maté ( Ilex paraguariensis) processed by gamma radiation  

NASA Astrophysics Data System (ADS)

The radiation food processing has been demonstrating great effectiveness in the attack of pathogenic agents, while little compromising nutritional value and sensorial properties of foods. The maté ( Ilex paraguariensis), widely consumed product in South America, generally in the form of infusions with hot or cold water, calls of chimarrão or tererê, it is cited in literature as one of the best sources phenolic compounds. The antioxidants action of these constituent has been related to the protection of the organism against the free radicals, generated in alive, currently responsible for the sprouting of some degenerative illness as cancer, arteriosclerosis, rheumatic arthritis and cardiovascular clutters among others. The objective of that work was to evaluate the action of the processing for gamma radiation in phenolic compounds of tererê beverage in the doses of 0, 3, 5, 7 and 10 kGy. The observed results do not demonstrate significant alterations in phenolic compounds of tererê beverage processed by gamma radiation.

Furgeri, C.; Nunes, T. C. F.; Fanaro, G. B.; Souza, M. F. F.; Bastos, D. H. M.; Villavicencio, A. L. C. H.

2009-07-01

279

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

280

Influence of hyperthermia and. gamma. radiation on ADP-ribosyl transferase, NAD/sup +/, and ATP pools in human mononuclear leukocytes  

SciTech Connect

Effects of hyperthermia (42.5/sup 0/C) and ..gamma.. radiation (30 Gy) on ADP-ribosyl transferase, NAD/sup +/, and ATP pools in human mononuclear leukocytes have been investigated. It was found that the ..gamma..-ray activation level of the enzyme was not influenced by this hyperthermia for 45 min. Following deprivation of ATP synthesis by 2,4-dinitrophenol, an uncoupler of the oxidative phosphorylation, and omitting glucose from the culture medium, the NAD/sup +/ pool was reduced to about 60% of control value. The potentiation of ATP production by exogenously supplied adenosine was reduced after a combined treatment of the cells with hyperthermia and ..gamma.. radiation. Mitochondrial and endoplasmic changes within the mononuclear leukocytes were also observed. Based on these findings a model for the hyperthermia effect is proposed.

Jonsson, G.G.; Eriksson, G.; Pero, R.W.

1985-05-01

281

Effects of long-term and chronic radiation on hemopoiesis. [. gamma. rays; rats  

Microsoft Academic Search

Ionizing radiation is one of the adverse factors of space flights. The possibility of exposure to solar and galactic radiation makes it necessary to develop methods for assessing the radiation hazard and substantiating maximum permissible levels of long-term and chronic irradiation. Evaluation of the sequelae of such factors affecting repair capabilities of hemopoiesis is of definite interest, in view of

Zukhbaya

1978-01-01

282

The COS-B experiment and mission. [high energy extraterrestrial gamma radiation  

NASA Technical Reports Server (NTRS)

The COS-B satellite carries a single experiment, capable of detecting gamma rays with energies greater than 30 MeV to study the spatial, energy, and time characteristics of high-energy radiation of galactic and extragalactic origin. The capability to search for gamma ray pulsations is enhanced by the inclusion in the payload of a proportional counter sensitive of X-rays of 2 to 12 keV. The experiment was calibrated using particle accelerators. The results of these measurements are presented, and the performance of the system in orbit is discussed.

1977-01-01

283

A new integrated neutron/gamma radioisotope identification device evaluated under mixed radiation fields  

NASA Astrophysics Data System (ADS)

Hand-Held RadioIsotope Identification Devices (HHRIID) are defined as a new class of portable neutron/gamma radiation detectors with specifications presented in the ANSI Standards N42.33 and N42.34. We have proposed a novel HHRIID design concept which uses a single photosensor to detect light emitted by two optically separated scintillator materials, one optimized for gamma detection and the other optimized for neutron detection. This work describes the performance of a modified charge integration discrimination method developed to test the viability of the new design. The scintillators chosen for the experiment were LYSO and ZnS:Ag/LiF.

Ivan, Adrian; Clothier, Brent A.; McDevitt, Daniel B.; Williams, James

2008-04-01

284

Development and characterization of the integrated fiber-optic radiation sensor for the simultaneous detection of neutrons and gamma rays.  

PubMed

Sometimes, detection of thermal neutrons in the presence of gamma rays is required. This study developed and characterized an integrated fiber-optic radiation sensor for the simultaneous detection of thermal neutrons and gamma rays in a mixed radiation field. The performance of the integrated sensor was verified by measuring the distributions of thermal neutrons and gamma rays released from a nuclear fuel rod at the Kyoto University Critical Assembly. The experimental results show that the integrated sensor produced similar distribution patterns to those of thermal neutrons and gamma rays released from a fuel rod. PMID:21277213

Jang, Kyoung Won; Lee, Bong Soo; Moon, Joo Hyun

2011-04-01

285

Current response of a TlBr detector to {sup 137}Cs {gamma}-ray radiation  

SciTech Connect

The current response of a TlBr detector to {sup 137}Cs {gamma}-ray radiation has been studied in the dose-rate range 0.033-3.84 Gy/min and within the voltage range 1-300 V; the detectors are based on pure and doped TlBr crystals grown from the melt by the Bridgman-Stockbarger method. The mass fraction of Pb or Ca introduced into the TlBr crystals was 1-10 ppm for Pb and 150 ppm for Ca. The current response of nominally undoped TlBr samples was nearly linear over two decades of studied dose rates. Deep hole levels associated with cationic vacancies V{sub c}{sup -} determine the dependence of the current response on the voltage in the high electric fields. The parameters of the carriers' transport {mu}{tau} are determined. The TlBr crystals grown in vacuum and in the bromine vapor exhibit a large mobility-lifetime product of 4.3 Multiplication-Sign 10{sup -4} and 6.4 Multiplication-Sign 10{sup -5} cm{sup 2}V{sup -1}, respectively. The value of {mu}{tau} is in the range (4-9) Multiplication-Sign 10{sup -5} cm{sup 2}V{sup -1} for crystals doped with a divalent cation.

Gazizov, I. M., E-mail: gazizov@isotop.dubna.ru [Institute for Physico-Technical Problems (Russian Federation); Zaletin, V. M. [Dubna University (Russian Federation); Kukushkin, V. M.; Khrunov, V. S. [Institute for Physico-Technical Problems (Russian Federation)

2011-05-15

286

Monitoring of atmospheric gamma radiation and radon observations of rainfall events in southeast of Brazil  

NASA Astrophysics Data System (ADS)

It is well known that we live in an environment that is under the influence of radioactivity. Radioactive elements in Earth's crust, cosmic rays, and anthropogenic sources contribute to the radiation of different types (alpha, beta, gamma and X-rays) that can be measured. An interesting phenomenon associated with environmental radioactivity is radon washout wherein the radon gas that is produced by the decay of natural radioactive elements and released into the atmosphere is concentrated near ground by falling rain. Rain drops trap radon in their interior and transport this radioactive gas to the surface. In this study, we describe the monitoring of the localized and temporary increase in the natural radioactivity caused by radon washout using a 3"x 3" NaI(Tl) scintillator. Variations in the radioactivity were correlated with changes in meteorological conditions. We observed that even though rainfall is a main factor in the increase of natural radioactivity near ground, other factors such as the presence of fog and winds play an important role in the concentration and dispersion of radon. Because of the low cost of our experimental set up, we believe that this is an experiment that could easily be conducted in most universities and could also be used to monitor environmental radioactivity levels.

Martin, I. M.; Alves, M. A.; Gomes, M. P.

2013-05-01

287

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

288

High-efficiency scintillation detector for combined of thermal and fast neutrons and gamma radiation  

DOEpatents

A scintillation based radiation detector for the combined detection of thermal neutrons, high-energy neutrons and gamma rays in a single detecting unit. The detector consists of a pair of scintillators sandwiched together and optically coupled to the light sensitive face of a photomultiplier tube. A light tight radiation pervious housing is disposed about the scintillators and a portion of the photomultiplier tube to hold the arrangement in assembly and provides a radiation window adjacent the outer scintillator through which the radiation to be detected enters the detector. The outer scintillator is formed of a material in which scintillations are produced by thermal-neutrons and the inner scintillator is formed of a material in which scintillations are produced by high-energy neutrons and gamma rays. The light pulses produced by events detected in both scintillators are coupled to the photomultiplier tube which produces a current pulse in response to each detected event. These current pulses may be processed in a conventional manner to produce a count rate output indicative of the total detected radiation even count rate. Pulse discrimination techniques may be used to distinguish the different radiations and their energy distribution.

Chiles, Marion M. (Knoxville, TN); Mihalczo, John T. (Oak Ridge, TN); Blakeman, Edward D. (Oak Ridge, TN)

1989-01-01

289

Health Effects of Exposure to Low-Level Ionizing Radiation  

Microsoft Academic Search

This book comprises chapters contributed, with one exception, by American scientists and physicians and inevitably it is very much biased towards the American scene. Even so, the rest of us can draw parallel with our own societies. The book is aimed towards a medical audience and those in the radiation protection business, whose professional lives revolve around low level exposures,

David Lloyd

1997-01-01

290

LOW-LEVEL RADIATION HEALTH EFFECTS: PROGRAMS AND PANEL DISCUSSION  

E-print Network

41 LOW-LEVEL RADIATION HEALTH EFFECTS: PROGRAMS AND PANEL DISCUSSION Cosponsored by the Biology. Health Effects of Russian Nuclear Acci- dents: What Can We Learn? Richard Wilson, Alexander Shlyakhter sets concerning the health effects of ionizing radi- ation, which were collected by the scientists

Shlyakhter, Ilya

291

The social amplification of risk and low-level radiation  

Microsoft Academic Search

Some risk events, assessed as relatively minor by technical experts, can elicit strong public concerns and result in substantial impacts on society and the economy. This is especially true in cases involving low-level radiation exposure. Social amplification is a conceptual framework that seeks systematically to link technical assessments of health and safety impacts with assessments of individual and social risk

Roger E. Kasperson

2012-01-01

292

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

293

The Measurements of Neutron and Gamma Dose Rates in Mixed Radiation Fields, Using a Liquid Scintillation Counter.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Measurements of neutron and gamma dose rates in mixed radiation fields, and gamma dose rates from calibrated gamma sources, were performed using a liquid scintillation counter NE213 with a pulse shape discrimination technique based on the charge comparison method. A computer program was used to analyse the experimental data. The radiation field was obtained from a ^{241}Am-^9Be source. There was general agreement between measured and calculated neutron and gamma dose rates in the mixed radiation field, but some disagreement in the measurements of gamma dose rates for gamma sources, due to the dark current of the photomultiplier and the effect of the perturbation of the radiation field by the detector. An optical fibre bundle was used to couple an NE213 scintillator to a photomultipler, in an attempt to minimise these effects. This produced an improvement in the results for gamma sources. However, the optically coupled detector system could not be used for neutron and gamma dose rate measurements in mixed radiation fields. The pulse shape discrimination system became ineffective as a consequence of the slower time response of the detector system.

Shakshak, Bashir Ibrahim Omar

294

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

Code of Federal Regulations, 2010 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...

2010-07-01

295

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

296

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

297

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

298

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

299

Ionizing radiation effects on sex steroid hormone levels in serum and milt of freshwater fish Oreochromis mossambicus.  

PubMed

Effects of gamma rays on the sex steroid hormone levels [testosterone (T), 11-ketotestosterone (11-KT) and 17?-estradiol (E2)] were studied in the freshwater fish Oreochromis mossambicus. Gamma radiation induced effects on hormone levels reported here for the first time in the fish. Since radionuclides released accidentally or during a nuclear disaster can contaminate inland water bodies, biomonitoring methods are required for assessing the impacts of certain dose levels of radiation that may ultimately result in ionizing radiation exposure to both humans and non-human biota. Three groups of (n=15 in each group) fishes were irradiated with a single dose of (60)Co 10Gy, 15Gy and 20Gy with a duration of .33, .50 and .66min. Significant decrease of the hormone levels was seen at higher doses of 15Gy and 20Gy. The sex steroid hormone levels in the fishes are vital for sperm production, development, differential functions related to the physiology and reproductive behavior. This study serves as biomonitoring tool to assess the ionizing radiation effects on reproductive behavior of aquatic biota. PMID:24507134

Saiyad Musthafa, M; Jawahar Ali, A; Mohamed Ahadhu Shareef, T H; Vijayakumar, S; Iyanar, K; Thangaraj, K

2014-03-01

300

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

301

Bismuth germanate scintillators as detectors for high-energy gamma radiation  

NASA Astrophysics Data System (ADS)

The properties of bismuth germanate (BGO) relevant to the detection of high-energy gamma-rays are discussed on the basis of a comparison between a 76 mm diameter by 76 mm long BGO scintillator and a 152 mm diameter by 254 mm long NaI(Tl) crystal. The two detectors were exposed to monoenergetic gamma rays from the 12C(p, p'?) 12C reaction at the proton energy 17 MeV ( E? = 4.44, 12.71 and 15.11 MeV) and from the 1H(t, ?) 4He reaction at the triton energy 9 MeV( E? = MeV). The bismuth germanate detector has several properties which are important for the detection of high-energy gamma radiation.

Drake, Darrell M.; Nilsson, Leif R.; Faucett, John

302

Detection of galactic Al-26 gamma radiation by the SMM spectrometer  

NASA Technical Reports Server (NTRS)

The Solar Maximum Mission satellite's gamma-ray spectrometer has detected a line near 1.81 MeV in each of the three years (1980-1982) over which the Galactic center traversed the broad aperture of that instrument. No significant intensity variation is noted over this period. The Galactic center/anticenter intensity ratio is greater than 2.5, and the center of the emission is noted to be consistent with the location of the Galactic center. For an assumed source distribution which follows the more than 100 MeV Galactic gamma radiation, the total flux in the direction of the Galactic center and the measured energy of the line are consistent with the detection of a narrow gamma-ray line from interstellar Al-26 by HEAO 3 in 1979-1980.

Share, G. H.; Kinzer, R. L.; Kurfess, J. D.; Forrest, D. J.; Chupp, E. L.; Rieger, E.

1985-01-01

303

Degradation of cellulose nitrate with fast neutrons and gamma rays and their application in radiation dosimetry  

NASA Astrophysics Data System (ADS)

Fast and moderated neutrons emitted from 252Cf as well as low doses of gamma rays from 60Co, produce damaging effects in cellulose nitrate which can be determined viscometrically by calculating the average molecular weight at different doses. Samples were exposed to different doses of gamma rays (1 × 10 -4 to 1 Gy) and fission neutron fluences (10 5-10 11 n/cm 2) in free space and on a paraffin phantom. The effect of phantom thickness and phantom-to-detector distance on the detector readout have been investigated. The results revealed that the predominant bulk effects of radiation on CN is accelerated degradation by random chain scission. Empirical formulae have been given to calculate the absorbed doses of gamma rays and fast neutrons from the measured average molecular weight of the irradiated samples.

Fadel, M. A.; Khalil, W. A.; ABD-Alla, R. A.

1985-05-01

304

Lignocellulolytic mutants of Pleurotus ostreatus induced by gamma-ray radiation and their genetic similarities  

NASA Astrophysics Data System (ADS)

To induce the lignocellulolytic mutants of Pleurotus ostreatus, the mycelia were irradiated by gamma-ray radiation to doses of 1-2 kGy. Five strains were isolated by the criteria of clamp connection, fruiting body formation, growth rate and activities of extracellular enzymes. All isolated strains were able to form the fruiting bodies and grew similarly to the control. The extracellular enzymes activities in liquid media of isolated strains were up to 10 times higher than the control. Genetic similarities of the isolated strains ranged from 64.4% to 93.3% of the control. From these results, it seems that the genetic diversity of P. ostreatus could be changed and useful strains be induced by gamma-ray radiation to recycle or reuse biowastes.

Lee, Y.-K.; Chang, H.-H.; Kim, J.-S.; Kim, J. K.; Lee, K.-S.

2000-02-01

305

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

306

A multiple voxel model for scattered gamma radiation in pipe flow  

NASA Astrophysics Data System (ADS)

A multiple voxel model for scattered gamma radiation in pipe flow has been developed. The model has been used in the development of the dual modality densitometry measurement principle. In this measurement principle the gas volume fraction and the water salinity of an oil/water/gas pipe flow are measured by combining measurements of the intensity of scattered and transmitted radiation. The model has been applied to two different measurement geometries. The purpose of the model is to predict the intensity of scattered radiation at a detector position and to produce a three-dimensional spatial sensitivity map of the scatter generation. This is done by dividing the measurement volume into small cubic volumes; voxels. The contribution to the measured intensity of scattered radiation from each voxel is calculated and integrated for all voxels. The model has been verified by comparing with experiments and Monte Carlo simulations.

Tjugum, S. A.; Johansen, G. A.; Holstad, M. B.

2003-10-01

307

Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies  

NASA Astrophysics Data System (ADS)

The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

Docters, E. H.; Smolko, E. E.; Suarez, C. E.

308

Comparison of radiation damage in lead tungstate crystals under pion and gamma irradiation  

SciTech Connect

Studies of the radiation hardness of lead tungstate crystals produced by the Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of Ceramics in China have been carried out at IHEP, Protvino. The crystals were irradiated by a 40 GeV pion beam. After full recovery, the same crystals were irradiated using a {sup 137}Cs {gamma}-ray source. The dose rate profiles along the crystal length were observed to be quite similar. We compare the effects of the two types of radiation on the crystals light output.

Batarin, V.A.; Butler, J.; Davidenko, A.M.; Derevschikov, A.A.; Goncharenko, Y.M.; Grishin, V.N.; Kachanov, V.A.; Khodyrev, V.Y.; Konstantinov, A.S.; Kravtsov, V.I.; Kubota, Y.; Lukanin, V.S.; Matulenko, Y.A.; Melnick, Y.M.; Meschanin, A.P.; Mikhalin, N.E.; Minaev, N.G.; Mochalov, V.V.; Morozov, D.A.; Nogach, L.V.; Ryazantsev, A.V.; /Serpukhov,

2003-12-01

309

Degradation of biochemical activity in soil sterilized by dry heat and gamma radiation  

NASA Technical Reports Server (NTRS)

The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

Shih, K. L.; Souza, K. A.

1978-01-01

310

Inactivation of human immunodeficiency virus by gamma radiation and its effect on plasma and coagulation factors  

SciTech Connect

The inactivation of HIV by gamma-radiation was studied in frozen and liquid plasma; a reduction of the virus titer of 5 to 6 logs was achieved at doses of 5 to 10 Mrad at -80 degrees C and 2.5 Mrad at 15 degrees C. The effect of irradiation on the biologic activity of a number of coagulation factors in plasma and in lyophilized concentrates of factor VIII (FVIII) and prothrombin complex was examined. A recovery of 85 percent of the biologic activity of therapeutic components present in frozen plasma and in lyophilized coagulation factor concentrates was reached at radiation doses as low as 1.5 and 0.5 Mrad, respectively. As derived from the first-order radiation inactivation curves, the radiosensitive target size of HIV was estimated to be 1 to 3 MDa; the target size of FVIII was estimated to be 130 to 160 kDa. Gamma radiation must be disregarded as a method for the sterilization of plasma and plasma-derived products, because of the low reduction of virus infectivity at radiation doses that still give acceptable recovery of biologic activity of plasma components.

Hiemstra, H.; Tersmette, M.; Vos, A.H.; Over, J.; van Berkel, M.P.; de Bree, H. (Central Laboratory of The Netherlands, Red Cross Blood Transfusion Service, Amsterdam (Netherlands))

1991-01-01

311

Global verification of atmospheric gamma radiation as a monitor of precipitation and its dynamics  

Microsoft Academic Search

Changes in atmospheric gamma radiation rates (GRR) due to radon progeny adsorbed by rain measured at 6-20 m above ground may be used as a reliable monitor of rain and snow precipitation rates (RPR and SPR, respectively). Monitoring GRR in Mitaka, Japan with four 12.9 cm3 NaI detectors enabled consistent determinations of RPR and SPR to within 0.3 mm\\/hr limited

M. Greenfield; G. Austin; B. A. Demeijer; A. Domondon; J. Donoghue; S. Garimella; W. Henson; Y. Ikeda; R. L. Koomans; M. K. Kubo; J. Limburg; A. McArthur; A. Peace; D. Stow; M. Tomiyama; S. Tsuchiya

2003-01-01

312

Gamma ray bursts may be blueshifted bundles of the relic radiation  

E-print Network

A hypothesis is proposed that the gamma-ray bursts (GRBs) may arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The blueshift mechanism is provided by such a Lema\\^{\\i}tre -- Tolman (L--T) model, in which the bang-time function $t_B(r)$ is not everywhere constant. Blueshift arises on \\textit{radial} rays that are emitted over regions where $\\dril{t_B} r \

Krasi?ski, Andrzej

2015-01-01

313

Experiments on the GammaRadiation from Lithium and Fluorine Bombarded with Protons  

Microsoft Academic Search

The recoil electrons ejected from a 2 mm carbon scatterer by the gamma-radiation from Li+H1 have been investigated and indicate three lines of energies 17, 14.5, and 11.5 and possibly a fourth line of energy 8.5 Mev. Pairs ejected from the same scatterer were also observed. Most of these may be attributed to the 17 Mev line. Recoil electrons ejected

E. R. Gaerttner; H. R. Crane

1937-01-01

314

Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body  

PubMed Central

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500–1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1–10, it is considerably smaller than that suggested previously. PMID:19776147

Pattison, John E.; Hugtenburg, Richard P.; Green, Stuart

2010-01-01

315

Reduction of Quark Mass Scheme Dependence in B bar -> Xs gamma at the NNLL Level  

SciTech Connect

The uncertainty of the theoretical prediction of the B {yields} X{sub s}{gamma} branching ratio at NLL level is dominated by the charm mass renormalization scheme ambiguity. In this paper we calculate those NNLL terms which are related to the renormalization of m{sub c}, in order to get an estimate of the corresponding uncertainty at the NNLL level. We find that these terms significantly reduce (by typically a factor of two) the error on BR(B {yields} X{sub s}{gamma}) induced by the definition of m{sub c}. Taking into account the experimental accuracy of around 10% and the future prospects of the B factories, we conclude that a NNLL calculation would increase the sensitivity of the observable B {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM significantly.

Asatrian, H.M.; /Yerevan Phys. Inst.; Greub, C.; /Bern U.; Hovhannisyan, A.; /Yerevan Phys. Inst.; Hurth, T.; /CERN /SLAC; Poghosyan, V.; /Yerevan Phys. Inst.

2005-06-20

316

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

317

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

318

Radiosensitivity and Induction of Apoptosis by High LET Carbon Ion Beam and Low LET Gamma Radiation: A Comparative Study  

PubMed Central

Cancer treatment with high LET heavy ion beam, especially, carbon ion beam (12C), is becoming very popular over conventional radiotherapy like low LET gamma or X-ray. Combination of Poly(ADP-ribose) polymerase (PARP) inhibitor with xenotoxic drugs or conventional radiation (gamma or X-ray) is the newer approach for cancer therapy. The aim of our study was to compare the radiosensitivity and induction of apoptosis by high LET 12C and low LET gamma radiation in HeLa and PARP-1 knocked down cells. We did comet assay to detect DNA breaks, clonogenic survival assay, and cell cycle analysis to measure recovery after DNA damage. We measured apoptotic parameters like nuclear fragmentation and caspase-3 activation. DNA damage, cell killing, and induction of apoptosis were significantly higher for 12C than gamma radiation in HeLa. Cell killing and apoptosis were further elevated upon knocking down of PARP-1. Both 12C and gamma induced G2/M arrest although the 12C had greater effect. Unlike the gamma, 12C irradiation affects DNA replication as detected by S-phase delay in cell cycle analysis. So, we conclude that high LET 12C has greater potential over low LET gamma radiation in killing cells and radiosensitization upon PARP-1 inhibition was several folds greater for 12C than gamma. PMID:25018892

Ghorai, Atanu; Bhattacharyya, Nitai P.; Sarma, Asitikantha; Ghosh, Utpal

2014-01-01

319

DYNAMICS OF THE CHANGE IN THE AMOUNT OF INJECTED GAMMA GLOBULIN IN RABBIT BLOOD SERUM IN RADIATION SICKNESS  

Microsoft Academic Search

In the absence of information in the literature on the use of gamma ; globulin in radiation sickness, experiments were carried out on injected, ; irradiated animals. Into 22 rabbits totally irradiated with 800 r (LD\\/sub 30,30\\/; ), gamma globulin was injected intramuscularly in doses of 100 or 50 mg\\/kg 5 min ; before irradiation and of 25 mg\\/kg injected

Sosova

1963-01-01

320

Melatonin protection from chronic, low-level ionizing radiation.  

PubMed

In the current survey, we summarize the published literature which supports the use of melatonin, an endogenously produced molecule, as a protective agent against chronic, low-level ionizing radiation. Under in vitro conditions, melatonin uniformly was found to protect cellular DNA and plasmid super coiled DNA from ionizing radiation damage due to Cs(137) or X-radiation exposure. Likewise, in an in vivo/in vitro study in which humans were given melatonin orally and then their blood lymphocytes were collected and exposed to Cs(137) ionizing radiation, nuclear DNA from the cells of those individuals who consumed melatonin (and had elevated blood levels) was less damaged than that from control individuals. In in vivo studies as well, melatonin given to animals prevented DNA and lipid damage (including limiting membrane rigidity) and reduced the percentage of animals that died when they had been exposed to Cs(137) or Co(60) radiation. Melatonin's ability to protect macromolecules from the damage inflicted by ionizing radiation likely stems from its high efficacy as a direct free radical scavenger and possibly also due to its ability to stimulate antioxidative enzymes. Melatonin is readily absorbed when taken orally or via any other route. Melatonin's ease of self administration and its virtual absence of toxicity or side effects, even when consumed over very long periods of time, are essential when large populations are exposed to lingering radioactive contamination such as occurs as a result of an inadvertent nuclear accident, an intentional nuclear explosion or the detonation of a radiological dispersion device, i.e., a "dirty" bomb. PMID:22185900

Reiter, Russel J; Korkmaz, Ahmet; Ma, Shuran; Rosales-Corral, Sergio; Tan, Dun-Xian

2011-12-15

321

Elevated blood lead levels from exposure via a radiator workshop  

SciTech Connect

Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 {micro}mol/L, respectively. The father`s blood lead level was just below the Canadian occupational health and safety intervention level. The two children had blood lead levels of 1.0 and 0.8 {micro}mol/L, both of which are in excess of the recommended guideline for intervention in the case of children. The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

Treble, R.G.; Thompson, T.S. [Saskatchewan Health, Regina, Saskatchewan (Canada). Provincial Lab.] [Saskatchewan Health, Regina, Saskatchewan (Canada). Provincial Lab.; Morton, D.N. [North Battleford Medical Clinic, Saskatchewan (Canada)] [North Battleford Medical Clinic, Saskatchewan (Canada)

1998-04-01

322

Characterization of an Escherichia coli mutant (radB101) sensitive to. gamma. and uv radiation, and methyl methanesulfonate  

SciTech Connect

After N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis of Escherichia coli K-12 (xthA14), an X-ray-sensitive mutant was isolated. This sensitivity is due to a mutation, radB101, which is located at 56.5 min on the E.coli K-12 linkage map. The radB101 mutation sensitized wild-type cells to ..gamma.. and uv radiation, and to methyl methanesulfonate. When known DNA repair-deficient mutants were ranked for their ..gamma..-radiation sensitivity relative to their uv-radiation sensitivity, their order was (starting with the most selectively ..gamma..-radiation-sensitive strain): recB21, radB101, wild type, polA1, recF143, lexA101, recA56, uvrD3, and uvrA6. The radB mutant was normal for ..gamma..- and uv-radiation mutagenesis, it showed only a slight enhancement of ..gamma..- and uv-radiation-induced DNA degradation, and it was approx. 60% deficient in recombination ability. The radB gene is suggested to play a role in the recA gene-dependent (Type III) repair of DNA single-strand breaks after ..gamma.. irradiation and in postreplication repair after uv irradiation for the following reasons: the radB strain was normal for the host-cell reactivation of ..gamma..- and uv-irradiated bacteriophage lambda; the radB mutation did not sensitize a recA strain, but did sensitize a polA strain to ..gamma.. and uv radiation; the radB mutation sensitized a uvrB strain to uv radiation.

Sargentini, N.J.; Smith, K.C.

1983-03-01

323

RADIATION SENSITIVITY AND QUALITY OF FRESH-CUT VEGETABLES EXPOSED TO GAMMA RADIATION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thirteen fresh-cut (minimally processed) vegetables (broccoli, cilantro, red cabbage, endive, parsley, green and red leaf lettuce, Iceberg and Romaine lettuce, spinach, carrots, green onions, and celery) plus alfalfa sprouts were gamma irradiated at doses up to 3 kGy at 0.5 kGy intervals. The sample...

324

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

325

DNA damage caused by chronic transgenerational exposure to low dose gamma radiation in Medaka fish ( Oryzias latipes ).  

PubMed

The effect of transgenerational exposure to low dose rate (2.4 and 21 mGy/day) gamma irradiation on the yield of DNA double-strand breaks and oxidized guanine (8-hydroxyguanine) has been studied in the muscle and liver tissue of a model organism, the Japanese medaka fish. We found the level of unrepaired 8-hydroxyguanine in muscle tissue increased nonlinearly over four generations and the pattern of this change depended on the radiation dose rate, suggesting that our treatment protocols initiated genomic instability and an adaptive response as the generations progressed. The yield of unrepaired double-strand breaks did not vary significantly among successive generations in muscle tissue in contrast to liver tissue in which it varied in a nonlinear manner. The 8-hydroxyguanine and DSB radiation yields were significantly higher at 2.4 mGy/day than at 21 mGy/day in both muscle and liver tissue in all generations. These data are consistent with the hypothesis of a threshold for radiation-induced activation of DNA repair systems below which tissue levels of DNA repair enzymes remain unchanged, leading to the accumulation of unrepaired damage at very low doses and dose rates. PMID:23919310

Grygoryev, D; Moskalenko, O; Hinton, T G; Zimbrick, J D

2013-09-01

326

On the level of background radiation aboard a passenger airplane  

NASA Astrophysics Data System (ADS)

Data on radioactivity measured aboard an airplane during two flights—Moscow-Tivat and Tivat-Moscow—are given. Radioactivity was measured every minute during these flights (from takeoff to landing) simultaneously with two radiometers (RD1706). These flights were at a height of about 10.7 km. From the end of ascension to the start of descension, the radiation was approximately at the same level (about 3 ?Sv/h), which is approximately 30 times higher than that for the land surface. A comparison of data obtained with these two instruments during these flights yielded their sufficiently good agreement. On the basis of measurement results, the probability of negative radiation effects on air passengers is assessed using available methodical recommendations. For a single flight, at average solar-activity levels, this probability proved to be negligibly small (about 3 × 10-7).

Sidorin, A. I.

2014-12-01

327

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

328

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.

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

2014-01-01

329

Semiquantitative probe for radiation-induced normal tissue damage at the molecular level  

SciTech Connect

Sheep antibodies to bovine type I collagen were employed in the immunohistochemical detection of type I collagen in lung tissue sections of irradiated LAF1 mice. A video image digitizing system was developed to estimate collagen levels, by assigning a numerical value (0-63) to each of approximately 53,800 picture elements (pixels) in the microscope field, according to the collagen-dependent fluorescence intensity at each locus. For lungs harvested 52 weeks subsequent to graded doses of 60Co gamma radiation between 0 and 10 Gy, a dose-dependent increase in type I collagen was observed in the alveolar walls. A reproducible increase was evident for doses as low as 5 Gy: doses of 7 to 10 Gy elicited type I collagen levels significantly elevated with respect to those of age-matched controls. These results are consistent with a role for type I collagen in the development of radiation-induced pulmonary fibrosis. The assay system developed here will be used to explore the role of connective tissue macromolecules in the development of radiation pneumonitis and fibrosis.

Miller, G.; Siemann, D.; Scott, P.; Dawson, D.; Muldrew, K.; Trepanier, P.; McGann, L.

1986-01-01

330

Morphological and histological studies on freshwater prawn Macrobrachium rosenbergii (de man) irradiated with (60)Co gamma radiation.  

PubMed

This study was framed to investigate the (60)Co gamma radiation induced morphological and histological variations in freshwater prawn Macrobrachium rosenbergii. The LD50 value of (60)Co gamma irradiated M. rosenbergii observed (by probit analysis) at 30 Gy. Prawns were irradiated to four different dose levels (3 mGy, 30 mGy, 300 mGy and 3,000 mGy) using Theratron Phoenix TeleCobalt Unit [P-33] and one control group (without irradiation) maintained separately. Irradiated groups exhibited several morphological variations such as discoloration; damaged rostrum; opaque coloration in cephalothorax; black bands and dot formation in abdomen; deformed uropods and telson in tail regions when compared with control group. The Hepato Somatic Index reflected the severity of radiation on hepatopancreas. Histological variations in gills, hepatopancreas and muscles of irradiated groups were observed. In gills, structural changes such as swollen and fused lamellae, abnormal gill tips, hyperplasic, necrotic and clavate-globate lamellae were observed in gamma irradiated prawns. Accumulation of hemocytes in hemocoelic space, interstitial sinuses filled with abnormal infiltrated hemocytes, the tubular epithelium with ruptured basal laminae, abnormal and coagulated lumen, necrotic tubules, thickened basal laminae, tissue debris, necrotic hepatocytes were observed in irradiated prawn hepatopancreas. In muscle, shrinkage of muscular fiber and necrotic musculature were observed in irradiated prawns. These structural alterations of the organs it is felt could affect the vital physiological functions such as respiration, osmotic and ionic regulation in gills and muscles; absorption, storage and secretion of the hepatopancreas which in turn could adversely affect the growth and survival of freshwater prawn M. rosenbergii. PMID:24140570

Stalin, A; Broos, K V; Sadiq Bukhari, A; Syed Mohamed, H E; Singhal, R K; Venu-Babu, P

2013-11-15

331

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

332

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. PMID:25431791

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

2014-01-01

333

Gamma-magnetic normalization - new effect to reduce flux-gate magnetometer noise level  

NASA Astrophysics Data System (ADS)

It is the author's opinion confirmed by numerous experiments, that the FGM noise level (NL) is determined not by Barkhausen jumps during the core remagnetization from positive to negative state as the majority of designers believe, but by non-repeatability of the magnetic domains transition from negative to positive states and back. This shows the way how to reduce the magnetic noise: to manufacture the magnetic material with a structure which will create conditions for magnetic domain walls to glide easily and uniformly when changing their orientation leading to minimal efforts at cyclic remagnetization. Ideally, such a material may be represented as a solid "liquid" with freely floating uniform magnetic domains without walls friction. To reduce the specific NL of the materials, several post-melting processing technologies were developed. A set of experiments made by many investigators has shown that the best results gives the magnetic materials annealing in vacuum or in any inert gas applying by this during all annealing time the alternative magnetic field, imitating core excitation field during FGM operation. If to accept the "solid liquid" model, this mechanism of NL decreasing has clear physical explanation: permanent re-magnetization of domains leads to the structural improvements favorable namely for the homogenization of transitions, rise of temperature gives necessary energy for the impurities liquidation. Probably, M. Acuna was the first who reported that during FGM operation in space its NL is decreasing with time and attributed this to the relaxation of mechanical stresses in the core material in weightlessness conditions [1]. We studied in details the conditions in which the core material is in space: weightlessness, vacuum and radiation. Mechanical stresses relaxation hypothesis was rejected because the internal forces in any solid body are much stronger as those to which a gravity force might have influence. Also the tests of FGM sensor in vacuum chamber both in operation and switched off conditions showed any influence of this parameter on NL. And radiation influence, the dose of which was selected approximately equal to yearly dose at near-Earth orbit (~10 krad), revealed interesting facts: the magnetic material itself and the FGM sensor in non-operation state showed any dependence on radiation, whereas this dose applied to the operating FGM sensor lead to the marked NL reducing. This new effect was named "gamma-magnetic normalization" and also can be explained by the accepted model: the mechanism is the same as above, but, because ?-quantum have much greater energy as thermal one, more "rigid" impurities are eliminated at ?-radiation action. The experimental results confirming this hypothesis are presented in the report. This work was partially supported by NASU Contract 1-71/11/1531. [1] Acuna M M, 2002. Space based magnetometers. Rev. Sci. Instr. 73(11) pp. 3717-36.

Korepanov, V.

2012-04-01

334

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

335

Radiative-neutron-capture gamma-ray analysis by a linear combination technique  

USGS Publications Warehouse

The linear combination technique, when applied to a gamma-ray spectrum, gives a single number indicative of the extent to which the spectral lines of a sought element are present in a complex spectrum. Spectra are taken of the sought element and of various other substances whose spectra interfere with that of the sought element. A weighting function is then computed for application to spectra of unknown materials. The technique was used to determine calcium by radiative-neutron-capture gamma-ray analysis in the presence of interfering elements, notably titanium, and the results were compared with those for two popular methods of peak area integration. Although linearity of response was similar for the methods, the linear combination technique was much better at rejecting interferences. For analyses involving mixtures of unknown composition the technique consequently offers improved sensitivity. ?? 1972.

Tanner, A.B.; Bhargava, R.C.; Senftle, F.E.; Brinkerhoff, J.M.

1972-01-01

336

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

337

Gamma radiation induced effects in floppy and rigid Ge-containing chalcogenide thin films  

SciTech Connect

We explore the radiation induced effects in thin films from the Ge-Se to Ge-Te systems accompanied with silver radiation induced diffusion within these films, emphasizing two distinctive compositional representatives from both systems containing a high concentration of chalcogen or high concentration of Ge. The studies are conducted on blanket chalcogenide films or on device structures containing also a silver source. Data about the electrical conductivity as a function of the radiation dose were collected and discussed based on material characterization analysis. Raman Spectroscopy, X-ray Diffraction Spectroscopy, and Energy Dispersive X-ray Spectroscopy provided us with data about the structure, structural changes occurring as a result of radiation, molecular formations after Ag diffusion into the chalcogenide films, Ag lateral diffusion as a function of radiation and the level of oxidation of the studied films. Analysis of the electrical testing suggests application possibilities of the studied devices for radiation sensing for various conditions.

Ailavajhala, Mahesh S.; Mitkova, Maria [Department of Electrical Engineering, Boise State University, 1910 University Dr. Boise, Idaho 83725-2075 (United States); Gonzalez-Velo, Yago; Barnaby, Hugh; Kozicki, Michael N.; Holbert, Keith [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287-9309 (United States); Poweleit, Christian [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Butt, Darryl P. [Department of Material Science and Engineering, Boise State University, 1910 University Dr. Boise, Idaho 83725-2090 (United States)

2014-01-28

338

Effect of gamma radiation on chlorobutyl rubber vulcanized by three different crosslinking systems  

NASA Astrophysics Data System (ADS)

The development of halogenated butyl rubber (chlorobutyl) in the 1950s and 1960s greatly extended the usefulness of butyl. Their properties allowed the development of more durable tubeless tires with the air retaining innerliner, chemically bonded to the body of the tire. Tire innerliners are by far the largest application for halobutyl. When polymers are subjected to high energy radiation, a number of chemical reactions may occur following the initial ionization and excitation events. These reactions lead to changes in the molecular weight of the polymer through scission (S) and crosslinking (X) of the molecules and affect the physical and mechanical properties. In the halobutyl rubbers the chain scission may predominate. This work aims to show effects of gamma radiation in properties of chlorobutyl rubbers vulcanized with sulfur, sulfur donor and phenolic resin. The butyl rubber has been already studied by us previously. The samples were characterized before and after irradiation. Gamma radiation doses used were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 kGy, in order to identify which cure system is the most stable under irradiation. In this study we observed that the properties of all samples were affected irrespective of the vulcanization system.

Scagliusi, Sandra R.; Cardoso, Elisabeth L. C.; Lugao, Ademar B.

2012-09-01

339

Airborne gamma radiation measurements of soil moisture during FIFE: Activities and results  

NASA Technical Reports Server (NTRS)

Soil moisture measurements were obtained during the summer of 1987 and 1989 near Manhattan, Kansas, using the National Weather Service (NWS) airborne gamma radiation system. A network of 24 flight lines were established over the research area. Airborne surveys were flown daily during two intensive field campaigns. The data collected was sufficient to modify the NWS standard operational method for estimating soil moisture for the Field Experiment (FIFE) flight lines. The average root mean square error of the soil moisture estimates for shorter FIFE flight lines was found to be 2.5 percent, compared with a reported value of 3.9 percent for NWS flight lines. Techniques were developed to compute soil moisture estimates for portions of the flight lines. Results of comparisons of the airborne gamma radiation soil moisture estimates with those obtained using the NASA Pushbroom Microwave Radiation (PBMR) system and hydrological model are presented. The airborne soil moisture measurements, and real averages computed using all remotely sensed and ground data, have been in support of the research of the many FIFE investigators whose overall goal was the upscale integration of models and the application of satellite remote sensing.

Peck, Eugene L.

1992-01-01

340

Gamma radiation process for destruction of toxic polychlorinated biphenyls (Pcbs) in transformer oils.  

PubMed

Polychlorinated biphenyls (PCBs) are synthetic organic chemicals commercially used worldwide in many applications. PCBs were used in oils because of their excellent properties such as good thermal stability, flame resistance, dielectric constant, high break down voltage, high boiling point and low volatility. However, because of their adverse affects on environment and human health, the use of PCBs has been banned now. PCBs are today considered among the widespread pollutants in the global system. PCBs sources still exist in various industrial products and in waste streams such as capacitor oils, lubricating oils, transformer oils, hydraulic oils, paints, rubbers, cables, etc. Several such materials containing PCBs emanating from various sources need to be detoxified before their reuse or before going to landfill for final disposal. Various remedial technologies have been developed in the world to destroy toxic PCBs. The radiolysis has been investigated as an environment-friendly process for waste oil treatment contaminated with PCBs, which may be a better alternative to the globally most widely accepted incineration method. A study was undertaken to detoxify PCBs in transformer oil by gamma radiation using Cobalt 60 source. Analysis of PCBs in transformer oils before and after radiation was carried out by GC-MS instrument. The effect of radiation dose and destruction of PCBs in transformer oils are discussed in details in the present paper. The method used was found to be highly effective and destruction was as high as 79 %. Further, the transformer oil samples were also evaluated before and after radiation to check their quality. The properties of oils were not significantly altered by gamma radiation treatment as evident from the results given in the paper. PMID:17913201

Singh, R K; Nayak, Poonam; Niyogi, U K; Khandal, R K; Singh, Gurdeep

2006-01-01

341

Abdominal {gamma}-Radiation Induces an Accumulation of Function-Impaired Regulatory T Cells in the Small Intestine  

SciTech Connect

Purpose: To assess the frequency and the functional characteristics of one major component of immune tolerance, the CD4{sup +}FoxP3{sup +} regulatory T cells (Tregs) in a mouse model of abdominal irradiation. Methods and Materials: Mice were exposed to a single abdominal dose of {gamma}-radiation (10 Gy). We evaluated small intestine Treg infiltration by Foxp3 immunostaining and the functional suppressive activity of Tregs isolated from mesenteric lymph nodes. Results: Foxp3 immunostaining showed that radiation induced a long-term infiltration of the intestine by Tregs (levels 5.5 times greater than in controls). Co-culture of Tregs from mesenteric lymph nodes with CD4{sup +} effector cells showed that the Tregs had lost their suppressive function. This loss was associated with a significant decrease in the levels of Foxp3, TGF-{beta}, and CTLA-4 mRNA, all required for optimal Treg function. At Day 90 after irradiation, Tregs regained their suppressive activity as forkhead box P3 (Foxp3), transforming growth factor beta (TGF-{beta}), and cytotoxic T-lymphocyte antigen 4 (CTLA-4) expression returned to normal. Analysis of the secretory function of mesenteric lymph node Tregs, activated in vitro with anti-CD3/anti-CD28 Abs, showed that this dysfunction was independent of a defect in interleukin-10 secretion. Conclusion: Radiation caused a long-term accumulation of function-impaired Foxp3{sup +}CD4{sup +} Tregs in the intestine. Our study provides new insights into how radiation affects the immune tolerance in peripheral tissues.

Billiard, Fabienne; Buard, Valerie; Benderitter, Marc [Institut de Radioprotection et de Surete Nucleaire, Direction de la Radioprotection de l'Homme, B.P. no. 17, Fontenay-aux-Roses (France); Linard, Christine, E-mail: christine.linard@irsn.fr [Institut de Radioprotection et de Surete Nucleaire, Direction de la Radioprotection de l'Homme, B.P. no. 17, Fontenay-aux-Roses (France)

2011-07-01

342

Gamma radiation damage study of 0.18 µm process CMOS image sensors  

NASA Astrophysics Data System (ADS)

A 0.18 ?m process CMOS image sensor has recently been developed by e2v technologies plc. with a 0.5 megapixel imaging area consisting of 6 × 6 ?m 5T pixels. The sensor is able to provide high performance in a diverse range of applications including machine vision and medical imaging, offering good low-light performance at a video rate of up to 60 fps. The CMOS sensor has desirable characteristics which make it appealing for a number of space applications. Following on from previous tests of the radiation hardness of the image sensors to proton radiation, in which the increase in dark-current and appearance of bright and RTS pixels was quantified, the sensors have now been subjected to a dose of gamma radiation. Knowledge of the performance after irradiation is important to judge suitability for space applications and radiation sensitive medical imaging applications. This knowledge will also enable image correction to mitigate the effects and allow for future CMOS devices to be designed to improve upon the findings in this paper. One device was irradiated to destruction after 120 krad(Si) while biased, and four other devices were irradiated between 5 and 20 krad(Si) while biased. This paper explores the resulting radiation damage effects on the CMOS image sensor such as increased dark current, and a central brightening effect, and discusses the implications for use of the sensor in space applications.

Dryer, Ben; Holland, Andrew; Murray, N. J.; Jerram, Paul; Robbins, Mark; Burt, David

2010-07-01

343

The Radiations Emitted from Artificially Produced Radioactive Substances IV. Further Studies on the Gamma-Rays from Several Elements  

Microsoft Academic Search

Further studies on the gamma-radiation from V48, N13, Cu64, Mg27, and Na24 have been carried out using a large hydrogen-filled cloud chamber and with several improvements in technique. The most striking feature of the spectra, is the presence of a large amount of 1 Mev radiation from V48. Comparison with the ordinary annihilation radiation indicates that there are four 1

J. Reginald Richardson

1938-01-01

344

Radiative lifetimes for 80 levels of singly ionized erbium  

NASA Astrophysics Data System (ADS)

Radiative lifetimes, accurate to ±5%, have been measured for 8 even-parity and 72 odd-parity levels of singly ionized erbium using time-resolved laser-induced fluorescence (LIF) on Er ions in a beam. This new set of measurements is more extensive than earlier LIF sets, and is in good agreement with those sets where they overlap. These lifetimes provide an absolute scale for a large, accurate set of Er \\\\sc II atomic transition probabilities. Basic spectroscopic data on rare earth transition probabilities are needed for astrophysical research and for research on lighting products.

Stockett, M. H.; Den Hartog, E. A.; Lawler, J. E.

2007-12-01

345

Effects of alpha and gamma radiation on glass reaction in an unsaturated environment  

SciTech Connect

Radiation may effect the long-term performance of glass in an unsaturated repository site by interacting with air, water vapor, or liquid water. The present study examines (1) the effects of alpha or gamma irradiation in a water vapor environment, and (2) the influence of radiolytic products on glass reaction. Results indicate that nitric and organic acids form in an irradiated water vapor environment and are dissolved in thin films of condensed water. Glass samples exposed to these conditions react faster and have a different assemblage of secondary phases than glasses exposed to nonirradiated water vapor environments. 23 refs., 4 figs., 2 tabs.

Wronkiewicz, D.J.; Young, J.E.; Bates, J.K.

1990-12-31

346

Effective Atomic Numbers of Lanthanides with Gamma Radiation for Photon Energy Absorption  

NASA Astrophysics Data System (ADS)

Effective atomic numbers for photon energy absorption, ZPEA,eff have been calculated for photon from 1 keV to 20 MeV for selected oxides of lanthanides, such as Lanthanum oxide, Cerium oxide, Samarium oxide, Europium oxide, Dysprosium oxide, Thulium oxide, Ytterbium oxide. The ZPEA,eff values then compared with ZPI,eff for photon interaction. The ZPEA,eff values have been found to change with energy and composition of selected lanthanides. Oxides of lanthanides are considered as better shielding materials to the exposure of gamma radiation. The values of effective atomic number for photon energy absorption help in the calculation of absorbed dose.

Shantappa, Anil; Hanagodimath, S. M.

347

Effect of gamma radiation on low density polyethylene (LDPE) films: Optical, dielectric and FTIR studies  

NASA Astrophysics Data System (ADS)

The low density polyethylene (LDPE) films were irradiated with gamma radiation in the dose range varied from 20 to 400 kGy. The induced changes in the chemical structure and dielectric properties for the irradiated films were investigated. The structure modifications: crystallinity as well as possible molecular changes of the polymer were recognized using Fourier Transform Infrared Spectroscopy (FTIR). The optical results were determined from transmission, reflection and absorption spectra for these films. The dielectric properties of these films were calculated using optical methods. Result indicates small variation in crystallinity which could be increased or decreased depending on the relative importance of the structural and chemical changes.

Moez, A. Abdel; Aly, S. S.; Elshaer, Y. H.

348

Energy response of agar-alanine phantom dosimeter to gamma radiation  

SciTech Connect

Calculations of the energy response of an electron paramagnetic resonance (EPR) signal induced by gamma radiation in an agar-alanine phantom dosimeter are presented. Theoretically calculated slopes of the EPR signal calibration lines are comparable with those obtained experimentally for low-(50 kVp), medium-(662 keV), and high-(15 MVp) energy photons. The sensitivity of the phantom dosimeter (EPR signal amplitude/Gray) varies less than 2% within the 150- to 20-MeV energy range. For energies above 150 keV, the influence of variations in the size of alanine crystals is negligible.

Ciesielski, B.; Wielopolski, L.; Reinstein, L.E.

1988-05-01

349

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

350

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

351

Spectral analysis of paramagnetic centers induced in human tooth enamel by x-rays and gamma radiation  

NASA Astrophysics Data System (ADS)

Based on study of spectral and relaxation characteristics, we have established that paramagnetic centers induced in tooth enamel by x-rays and gamma radiation are identical in nature. We show that for the same exposure dose, the intensity of the electron paramagnetic resonance (EPR) signal induced by x-radiation with effective energy 34 keV is about an order of magnitude higher than the amplitude of the signal induced by gamma radiation. We have identified a three-fold attenuation of the EPR signal along the path of the x-radiation from the buccal to the lingual side of a tooth, which is evidence that the individual had undergone diagnostic x-ray examination of the dentition or skull. We have shown that the x-ray exposure doses reconstructed from the EPR spectra are an order of magnitude higher than the applied doses, while the dose loads due to gamma radiation are equal to the applied doses. The data obtained indicate that for adequate reconstruction of individual absorbed doses from EPR spectra of tooth enamel in the population subjected to the combined effect of x-radiation and accidental external gamma radiation as a result of the disaster at the Chernobyl nuclear power plant, we need to take into account the contribution to the dose load from diagnostic x-rays in examination of the teeth, jaw, or skull.

Kirillov, V. A.; Kuchuro, I. I.

2010-03-01

352

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

353

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

354

Increased food intake following the manipulation of intracerebral dopamine levels with gamma-hydroxybutyrate  

Microsoft Academic Search

The administration of gamma-hydroxybutyric acid (GHB) initially causes a temporary “sleep-like” state during which there is an increase in forebrain dopamine levels. The present series of experiments examined whether in the period following the GHB-induced behavioural depression, when accumulated dopamine is dispersed, there is any behavioural evidence of increased dopaminergic activity. The first experiment, in which GHB was injected directly

P. Redgrave; E. B. Taha; L. White; P. Dean

1982-01-01

355

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

PubMed

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 CaF(2) and LiF TLD-100 were exposed at 14 points along the mine tunnels in order to estimate the mean (222)Rn concentration and the ambient dose equivalent during the summer season (November 2008 to February 2009). The values for the (222)Rn concentration at each monitoring site ranged from 1.8+/-0.1 kBqm(-3) to 6.0+/-0.5 kBqm(-3), with a mean value of 4.8 kBqm(-3), indicating that these measurements exceed in about three times the upper action level recommended by ICRP for workplaces. The correlations between radon and gamma radiation levels inside the mine were also investigated. Effective doses due to (222)Rn and gamma rays inside the mine were determined, resulting in negligible values to tourists. Considering the effective dose to the mine tourist guides, values exceeding 20mSv of internal contribution to the effective doses can be reached, depending on the number of working hours inside the mine. PMID:19945773

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

2010-02-01

356

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

357

Progenitors mobilized by gamma-tocotrienol as an effective radiation countermeasure.  

PubMed

The purpose of this study was to elucidate the role of gamma-tocotrienol (GT3)-mobilized progenitors in mitigating damage to mice exposed to a supralethal dose of cobalt-60 gamma-radiation. CD2F1 mice were transfused 24 h post-irradiation with whole blood or isolated peripheral blood mononuclear cells (PBMC) from donors that had received GT3 72 h prior to blood collection and recipient mice were monitored for 30 days. To understand the role of GT3-induced granulocyte colony-stimulating factor (G-CSF) in mobilizing progenitors, donor mice were administered a neutralizing antibody specific to G-CSF or its isotype before blood collection. Bacterial translocation from gut to heart, spleen and liver of irradiated recipient mice was evaluated by bacterial culture on enriched and selective agar media. Endotoxin in serum samples also was measured. We also analyzed the colony-forming units in the spleens of irradiated mice. Our results demonstrate that whole blood or PBMC from GT3-administered mice mitigated radiation injury when administered 24 h post-irradiation. Furthermore, administration of a G-CSF antibody to GT3-injected mice abrogated the efficacy of blood or PBMC obtained from such donors. Additionally, GT3-mobilized PBMC inhibited the translocation of intestinal bacteria to the heart, spleen, and liver, and increased colony forming unit-spleen (CFU-S) numbers in irradiated mice. Our data suggests that GT3 induces G-CSF, which mobilizes progenitors and these progenitors mitigate radiation injury in recipient mice. This approach using mobilized progenitor cells from GT3-injected donors could be a potential treatment for humans exposed to high doses of radiation. PMID:25423021

Singh, Vijay K; Wise, Stephen Y; Fatanmi, Oluseyi O; Scott, Jessica; Romaine, Patricia L P; Newman, Victoria L; Verma, Amit; Elliott, Thomas B; Seed, Thomas M

2014-01-01

358

On background radiation gradients--the use of airborne surveys when searching for orphan sources using mobile gamma-ray spectrometry.  

PubMed

Systematic background radiation variations can lead to both false positives and failures to detect an orphan source when searching using car-borne mobile gamma-ray spectrometry. The stochastic variation at each point is well described by Poisson statistics, but when moving in a background radiation gradient the mean count rate will continually change, leading to inaccurate background estimations. Airborne gamma spectrometry (AGS) surveys conducted on the national level, usually in connection to mineral exploration, exist in many countries. These data hold information about the background radiation gradients which could be used at the ground level. This article describes a method that aims to incorporate the systematic as well as stochastic variations of the background radiation. We introduce a weighted moving average where the weights are calculated from existing AGS data, supplied by the Geological Survey of Sweden. To test the method we chose an area with strong background gradients, especially in the thorium component. Within the area we identified two roads which pass through the high-variability locations. The proposed method is compared with an unweighted moving average. The results show that the weighting reduces the excess false positives in the positive background gradients without introducing an excess of failures to detect a source during passage in negative gradients. PMID:24321866

Kock, Peder; Rääf, Christopher; Samuelsson, Christer

2014-02-01

359

49 CFR 173.441 - Radiation level limitations and exclusive use provisions.  

...2014-10-01 2014-10-01 false Radiation level limitations and exclusive use provisions...Radioactive) Materials § 173.441 Radiation level limitations and exclusive use provisions...normally incident to transportation, the radiation level does not exceed 2...

2014-10-01

360

49 CFR 173.441 - Radiation level limitations and exclusive use provisions.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Radiation level limitations and exclusive use provisions...Radioactive) Materials § 173.441 Radiation level limitations and exclusive use provisions...normally incident to transportation, the radiation level does not exceed 2...

2013-10-01

361

49 CFR 173.441 - Radiation level limitations and exclusive use provisions.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Radiation level limitations and exclusive use provisions...Radioactive) Materials § 173.441 Radiation level limitations and exclusive use provisions...normally incident to transportation, the radiation level does not exceed 2...

2012-10-01

362

Determination of the natural radioactivity levels in north west of Dukhan, Qatar using high-resolution gamma-ray spectrometry.  

PubMed

This study is aimed at the determination of the activity concentrations of naturally occuring and technologically enhanced levels of radiation in 34 representative soil samples that have been collected from an inshore oil field area which was found to have, in a previous study, the highest observed value of 226Ra concentration among 129 soil samples. The activity concentrations of 238U and 226Ra have been inferred from gamma-ray transitions associated with their decay progenies and measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the values of the activity concentrations associated with the naturally occuring radionuclide chains for all the samples collected from NW Dukhan. Discrete-line, gamma-ray energy transitions from spectral lines ranging in energy from ?100 keV up to 2.6 MeV have been associated with characteristic decays of the various decay products within the 235.8U and 232Th radioactive decay chains. These data have been analyzed, under the assumption of secular equilibrium for the U and Th decay chains. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented. The weighted mean value of the activity concentrations of 226Ra in one of the samples was found to be around a factor of 2 higher than the values obtained in the previous study and approximately a factor of 10 higher than the accepted worldwide average value of 35 Bq/kg. The weighted mean values of the activity concentrations of 232Th and 40K were also deduced and found to be within the worldwide average values of 30 and 400 Bq/kg, respectively. Our previous study reported a value of 201.9±1.5Stat.±13Syst.Bq/kg for 226Ra in one sample and further investigation in the current work determined a measured value for 226Ra of 342.00±1.9Stat.±25Syst.Bq/kg in a sample taken from the same locality. This is significantly higher than all the other investigated soil samples in the current and previous works. Notably, the Th levels in the same sample are within the worldwide average expectations, implying that the increased 226Ra concentration arises from TENORM processes. PMID:22244196

Al-Sulaiti, Huda; Nasir, Tabassum; Al Mugren, K S; Alkhomashi, N; Al-Dahan, N; Al-Dosari, M; Bradley, D A; Bukhari, S; Matthews, M; Regan, P H; Santawamaitre, T; Malain, D; Habib, A

2012-07-01

363

A new technique for processing airborne gamma ray spectrometry data for mapping low level contaminations.  

PubMed

A new technique for processing airborne gamma ray spectrometry data has been developed. It is based on the noise adjusted singular value decomposition method introduced by Hovgaard in 1997. The new technique opens for mapping of very low contamination levels. It is tested with data from Latvia where the remaining contamination from the 1986 Chernobyl accident together with fallout from the atmospheric nuclear weapon tests includes 137Cs at levels often well below 1 kBq/m2 equivalent surface contamination. The limiting factors for obtaining reliable results are radon in the air, spectrum stability and accurate altitude measurements. PMID:10581680

Aage, H K; Korsbech, U; Bargholz, K; Hovgaard, J

1999-12-01

364

Measurements of activation induced by environmental neutrons using ultra low-level gamma-ray spectrometry.  

PubMed

The flux of environmental neutrons is being studied by activation of metal discs of selected elements. Near the earth's surface the total neutron flux is in the order of 10(-2) cm(-2)s(-1), which gives induced activities of a few mBq in the discs. Initial results from this technique, involving activation at ground level for several materials (W, Au, Ta, In, Re, Sm, Dy and Mn) and ultra low-level gamma-ray spectrometry in an underground laboratory located at 500 m.w.e., are presented. Diffusion of environmental neutrons in water is also measured by activation of gold at different depths. PMID:10724430

Martínez Canet, M J; Hult, M; Köhler, M; Johnston, P N

2000-03-01

365

Influence of gamma radiation on the gel rigidity index and binding capability of gelatin  

SciTech Connect

Changes in the rigidity indices of gelatin gel before and after gamma irradiation were characterized by dynamic mechanical testing, and the significance of these changes on the strength of granules was evaluated. Results illustrate the difficulty of obtaining reproducible values for gels containing less than 20% gelatin. However, rigidity indices for gels with a gelatin content of 20% and higher are consistent and may provide a useful controlling factor for preparation of gelatins of more precise specifications. The data indicate that rigidity degradation kinetics of several concentrations of gelatin gel at different radiation doses are complex, showing both increasing and decreasing rates. These findings strongly suggest that doses of less than 2.0 Mrad of gamma radiation should be used in order to obtain gelatins of acceptable quality for pharmaceutical applications. The crushing strength of granules of lactose powder granulated with irradiated gelatin reveals that the binding capability of such gelatin is significantly reduced. The results obtained for various size fractions and granule hardnesses containing different binder concentrations also suggest that particle size influences the granule strength to a lesser extent than does binder concentration and its consistency.

Fassihi, A.R.; Parker, M.S.

1988-10-01

366

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

367

Improvement of microbiological safety of sous-vide meals by gamma radiation  

NASA Astrophysics Data System (ADS)

Experimental batches of smoked-cured pork in stewed beans sauce were inoculated with spores of psychrotrophic Bacillus cereus, more heat and radiation resistant than spores of non-proteolytic C. botulinum. After vacuum packaging, the meals were treated with combinations of pasteurizing heat treatments and gamma irradiation of 5 kGy. Prior and after treatments, and periodically during storage at 10°C, total aerobic and total anerobic viable cell counts, and selectively, the viable cell counts of B. cereus and sulphite-reducing clostridia have been determined. The effects of the treatment order as well as addition of nisin to enhance the preservative efficiency of the physical treatments were also studied. Heat-sensitization of bacterial spores surviving irradiation occurred. The quality-friendly sous-vide cooking in combination with this medium dose gamma irradiation and/or nisin addition increased considerably the microbiological safety and the keeping quality of the meals studied. However, approx. 40% loss of thiamin content occurred as an effect of combination treatments, and adverse sensorial effects may also limit the feasible radiation doses or the usable concentrations of nisin.

Farkas, J.; Polyák-Fehér, K.; Andrássy, É.; Mészáros, L.

2002-03-01

368

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

369

Phase effects in the radiation chemistry of dl-camphor. [Gamma radiation  

SciTech Connect

The effect of mesomorphism on the radiation chemistry of the solid state is examined for the system dl-camphor, which has only a small entropy difference between the ..cap alpha.. and ..beta.. mesophases. The results of the radiolysis of these phases gave rise to the same products in both mesophases but with differences in the product G values in the two mesophases. These results are discussed in terms of the effect of phase on the overall mechanism for the formation of the observed products, which can be attributed to efficient abstraction reactions operative in the ..beta.. phase but not the ..cap alpha.. phase.

Klingen, T.J.; Sherman, L.R.; McCormick, D.G.

1980-12-11

370

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

371

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

372

The effect of perinatal sup 60 Co gamma radiation on brain weight in beagles  

SciTech Connect

Beagle dogs were given single, whole-body {sup 60}Co gamma-radiation exposures at one of three prenatal (8, 28, or 55 days postcoitus) or three postnatal (2, 70, or 365 days postpartum) ages to evaluate the relative radiosensitivity of various stages of brain development. A total of 387 dogs received mean doses ranging from 0.16 to 3.83 Gy, and 120 dogs were sham-irradiated. Groups of dogs were sacrificed at preselected times from 70 days to 11 years of age. Brain weight decreased significantly with increasing dose in dogs irradiated at 28 or 55 days postcoitus or at 2 days postpartum. Irradiations at 28 days postcoitus were dramatically more effective in causing a reduction in brain weight than those at 55 days postcoitus or 2 days postpartum. Among dogs given 1.0 Gy or more and followed for up to 4 years, there was a radiation effect evident at all three sensitive exposure ages. Among dogs given lower doses and followed for up to 11 years, there was a significant decrease in brain weight in dogs given 0.80-0.88 Gy at 28 days postcoitus. All decreases in brain weight were present after normalization for radiation-induced reductions in skeletal (body) size. No specific morphologic changes were noted in the brains which showed the radiation-related reductions in size.

Hamilton, B.F.; Benjamin, S.A.; Angleton, G.M.; Lee, A.C. (Colorado State Univ., Fort Collins (USA))

1989-08-01

373

Pilot scale-up and shelf stability of hydrogel wound dressings obtained by gamma radiation  

NASA Astrophysics Data System (ADS)

This study is aimed of producing pilot batches of hydrogel wound dressings by gamma radiation and evaluating their shelf stability. Six batches of 3L capacity were prepared based on poly(vinyl pyrrolidone), agar and polyethylene glycol and they were dispensed in polyester trays, covered with polyester films and sealed in two types of materials: polyethylene bags and vacuum polyethylene bags. Dressings were formed in a single step process for the hydrogel formation and sterilization at 25-30 kGy gamma radiation dose in a JS-9500 Gamma Irradiator (Nordion, Canada). The six batches were initially physicochemical characterized in terms of dimensions and appearance, gel fraction, morphology analysis, hydrogel strength, moisture retention capability and swelling capacity. They were kept under two storage conditions: room temperature (T: 30±2 °C/RH: 70± 5%) and refrigerated temperature (T: 5±3 °C) during 24 months and sterility test was performed. The appearance of membranes was transparent, clear, uncut and flexible; the gel fraction of batches was higher than 75% and the hydrogel surface showed a porous structure. There was a slow decrease of the compression rate 20% until 7 h and about 70% at 24 h. Moisture retention capability in 5 h was similar for all the batches, about 40% and 60% at 37 °C and at room temperature respectively. The swelling of hydrogels in acidic media was strong and in alkaline media the weight variation remains almost stable until 24 h and then there is a loss of weight. The six batches remained sterile during the stability study in the conditions tested. The pilot batches were consistent from batch to batch and remained stable during 24 months.

Soler, Dulce María; Rodríguez, Yanet; Correa, Hector; Moreno, Ailed; Carrizales, Lila

2012-08-01

374

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

375

Using RADFET for the real-time measurement of gamma radiation dose rate  

NASA Astrophysics Data System (ADS)

RADFETs (RADiation sensitive Field Effect Transistors) are integrating ionizing radiation dosimeters operating on the principle of conversion of radiation-induced threshold voltage shift into absorbed dose. However, one of the major drawbacks of RADFETs is the inability to provide the information on the dose rate in real-time using the conventional absorbed dose measurement technique. The real-time monitoring of dose rate and absorbed dose can be achieved with the current mode dosimeters such as PN and PIN diodes/photodiodes, but these dosimeters have some limitations as absorbed dose meters and hence they are often not a suitable replacement for RADFETs. In that sense, this paper investigates the possibility of using the RADFET as a real-time dose rate meter so that it could be applied for simultaneous online measurement of the dose rate and absorbed dose. A RADFET sample, manufactured by Tyndall National Institute, Cork, Ireland, was tested as a dose rate meter under gamma irradiation from a Co-60 source. The RADFET was configured as a PN junction, such that the drain, gate and source terminals were grounded, while the radiation-induced current was measured at the bulk terminal, whereby the bulk was successively biased with 0?, 10?, 20? and 30?V. In zero-bias mode the radiation-induced current was unstable, but in the biased mode the current response was stable for the investigated dose rates from 0.65? to 32.1?Gy?h?1 and up to the total absorbed dose of 25?Gy. The current increased with the dose rate in accordance with the power law, whereas the sensitivity of the current read-out was linear with respect to the applied bias voltage. Comparison with previously analyzed PIN photodiodes has shown that the investigated RADFET is competitive with PIN photodiodes as a gamma radiation dose rate meter and therefore has the potential to be employed for the real-time monitoring of the dose rate and absorbed dose.

Andjelkovi?, Marko S.; Risti?, Goran S.; Jakši?, Aleksandar B.

2015-02-01

376

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

377

Precise Measurement of the e+e--->pi+pi-(gamma) Cross Section with the Initial State Radiation Method at BABAR  

Microsoft Academic Search

A precise measurement of the cross section of the process e+e--->pi+pi-(gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232fb-1 of data collected with the BABAR detector at e+e- center-of-mass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic process e+e--->mu+mu-gamma(gamma). The leading-order hadronic

B. Aubert; Y. Karyotakis; J. P. Lees; V. Poireau; E. Prencipe; X. Prudent; V. Tisserand; J. Garra Tico; E. Grauges; M. Martinelli; A. Palano; M. Pappagallo; G. Eigen; B. Stugu; L. Sun; M. Battaglia; D. N. Brown; B. Hooberman; L. T. Kerth; Yu. G. Kolomensky; G. Lynch; I. L. Osipenkov; K. Tackmann; T. Tanabe; C. M. Hawkes; N. Soni; A. T. Watson; H. Koch; T. Schroeder; D. J. Asgeirsson; C. Hearty; T. S. Mattison; J. A. McKenna; M. Barrett; A. Khan; A. Randle-Conde; V. E. Blinov; A. D. Bukin; A. R. Buzykaev; V. P. Druzhinin; V. B. Golubev; A. P. Onuchin; S. I. Serednyakov; Yu. I. Skovpen; E. P. Solodov; K. Yu. Todyshev; M. Bondioli; S. Curry; I. Eschrich; D. Kirkby; A. J. Lankford; P. Lund; M. Mandelkern; E. C. Martin; D. P. Stoker; H. Atmacan; J. W. Gary; F. Liu; O. Long; G. M. Vitug; Z. Yasin; V. Sharma; C. Campagnari; T. M. Hong; D. Kovalskyi; M. A. Mazur; J. D. Richman; T. W. Beck; A. M. Eisner; C. A. Heusch; J. Kroseberg; W. S. Lockman; A. J. Martinez; T. Schalk; B. A. Schumm; A. Seiden; L. Wang; L. O. Winstrom; C. H. Cheng; D. A. Doll; B. Echenard; F. Fang; D. G. Hitlin; I. Narsky; P. Ongmongkolkul; T. Piatenko; F. C. Porter; R. Andreassen; G. Mancinelli; B. T. Meadows; K. Mishra; M. D. Sokoloff; P. C. Bloom; W. T. Ford; A. Gaz; J. F. Hirschauer; M. Nagel; U. Nauenberg; J. G. Smith; S. R. Wagner; R. Ayad; W. H. Toki; E. Feltresi; A. Hauke; H. Jasper; T. M. Karbach; J. Merkel; A. Petzold; B. Spaan; K. Wacker; M. J. Kobel; R. Nogowski; K. R. Schubert; R. Schwierz; D. Bernard; E. Latour; M. Verderi; P. J. Clark; S. Playfer; J. E. Watson; M. Andreotti; D. Bettoni; C. Bozzi; R. Calabrese; A. Cecchi; G. Cibinetto; E. Fioravanti; P. Franchini; E. Luppi; M. Munerato; M. Negrini; A. Petrella; L. Piemontese; V. Santoro; R. Baldini-Ferroli; A. Calcaterra; R. de Sangro; G. Finocchiaro; S. Pacetti; P. Patteri; I. M. Peruzzi; M. Piccolo; M. Rama; A. Zallo; R. Contri; E. Guido; M. Lo Vetere; M. R. Monge; S. Passaggio; C. Patrignani; E. Robutti; S. Tosi; M. Morii; A. Adametz; J. Marks; S. Schenk; U. Uwer; F. U. Bernlochner; H. M. Lacker; T. Lueck; A. Volk; P. D. Dauncey; M. Tibbetts; P. K. Behera; M. J. Charles; U. Mallik; J. Cochran; H. B. Crawley; L. Dong; V. Eyges; W. T. Meyer; S. Prell; E. I. Rosenberg; A. E. Rubin; Y. Y. Gao; A. V. Gritsan; Z. J. Guo; N. Arnaud; A. D'Orazio; M. Davier; D. Derkach; J. Firmino da Costa; G. Grosdidier; F. Le Diberder; V. Lepeltier; A. M. Lutz; B. Malaescu; P. Roudeau; M. H. Schune; J. Serrano; V. Sordini; A. Stocchi; G. Wormser; D. J. Lange; D. M. Wright; I. Bingham; J. P. Burke; C. A. Chavez; J. R. Fry; E. Gabathuler; R. Gamet; D. E. Hutchcroft; D. J. Payne; C. Touramanis; A. J. Bevan; C. K. Clarke; F. di Lodovico; R. Sacco; M. Sigamani; G. Cowan; S. Paramesvaran; A. C. Wren; C. L. Davis; M. Fritsch; W. Gradl; A. Hafner; K. E. Alwyn; D. Bailey; R. J. Barlow; G. Jackson; G. D. Lafferty; T. J. West; J. I. Yi; J. Anderson; C. Chen; A. Jawahery; D. A. Roberts; G. Simi; J. M. Tuggle; C. Dallapiccola; E. Salvati; R. Cowan; D. Dujmic; P. H. Fisher; S. W. Henderson; G. Sciolla; M. Spitznagel; R. K. Yamamoto; M. Zhao; P. M. Patel; S. H. Robertson; M. Schram; P. Biassoni; A. Lazzaro; V. Lombardo; F. Palombo; S. Stracka; L. Cremaldi; R. Godang; R. Kroeger; P. Sonnek; D. J. Summers; H. W. Zhao; X. Nguyen; M. Simard; P. Taras; H. Nicholson; G. de Nardo; L. Lista; D. Monorchio; G. Onorato; C. Sciacca; G. Raven; H. L. Snoek; C. P. Jessop; K. J. Knoepfel; J. M. Losecco; W. F. Wang; L. A. Corwin; K. Honscheid; H. Kagan; R. Kass; J. P. Morris; A. M. Rahimi; S. J. Sekula; N. L. Blount; J. Brau; R. Frey; O. Igonkina; J. A. Kolb; M. Lu; R. Rahmat; N. B. Sinev; D. Strom; J. Strube; E. Torrence; G. Castelli; N. Gagliardi; M. Margoni; M. Morandin; M. Posocco; M. Rotondo; F. Simonetto; R. Stroili; C. Voci; P. Del Amo Sanchez; E. Ben-Haim; G. R. Bonneaud; H. Briand; J. Chauveau; O. Hamon; Ph. Leruste; G. Marchiori; J. Ocariz; A. Perez; J. Prendki; S. Sitt; L. Gladney; M. Biasini; E. Manoni; C. Angelini; G. Batignani; S. Bettarini; G. Calderini; M. Carpinelli; A. Cervelli; F. Forti; M. A. Giorgi; A. Lusiani; M. Morganti; N. Neri; E. Paoloni; G. Rizzo; J. J. Walsh; D. Lopes Pegna; C. Lu; J. Olsen; A. J. S. Smith; A. V. Telnov; F. Anulli; E. Baracchini; G. Cavoto; R. Faccini; F. Ferrarotto; F. Ferroni; M. Gaspero; P. D. Jackson; L. Li Gioi; M. A. Mazzoni; S. Morganti; G. Piredda; F. Renga; C. Voena; M. Ebert; T. Hartmann; H. Schröder; R. Waldi; T. Adye; B. Franek; E. O. Olaiya; F. F. Wilson; S. Emery; L. Esteve; G. Hamel de Monchenault; W. Kozanecki; G. Vasseur; Ch. Yèche; M. Zito; M. T. Allen; D. Aston; D. J. Bard; R. Bartoldus; J. F. Benitez; R. Cenci; J. P. Coleman; M. R. Convery; J. C. Dingfelder; J. Dorfan; G. P. Dubois-Felsmann; W. Dunwoodie; R. C. Field; M. Franco Sevilla; B. G. Fulsom; A. M. Gabareen; M. T. Graham; P. Grenier; C. Hast; W. R. Innes

2009-01-01

378

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

379

A new analytical formula for neutron capture gamma dose calculations in double-bend mazes in radiation therapy  

PubMed Central

Background Photoneutrons are produced in radiation therapy with high energy photons. Also, capture gamma rays are the byproduct of neutrons interactions with wall material of radiotherapy rooms. Aim In the current study an analytical formula was proposed for capture gamma dose calculations in double bend mazes in radiation therapy rooms. Materials and methods A total of 40 different layouts with double-bend mazes and a 18 MeV photon beam of Varian 2100 Clinac were simulated using MCNPX Monte Carlo (MC) code. Neutron capture gamma ray dose equivalent was calculated by the MC method along the maze and at the maze entrance door of all the simulated rooms. Then, all MC resulted data were fitted to an empirical formula for capture gamma dose calculations. Wu–McGinley analytical formula for capture gamma dose equivalent at the maze entrance door in single-bend mazes was also used for comparison purposes. Results For capture gamma dose equivalents at the maze entrance door, the difference of 2–11% was seen between MC and the derived equation, while the difference of 36–87% was found between MC and the Wu–McGinley methods. Conclusion Our results showed that the derived formula results were consistent with the MC results for all of 40 different geometries. However, as a new formula, further evaluations are required to validate its use in practical situations. Finally, its application is recommend for capture gamma dose calculations in double-bend mazes to improve shielding calculations. PMID:24377027

Ghiasi, Hosein; Mesbahi, Asghar

2012-01-01

380

$gamma$RADIATION SPECTRA OF RADIOACTIVE ORES IN THEIR NATURAL DEPOSITS OBTAINED BY MEANS OF PROPORTIONAL COUNTERS  

Microsoft Academic Search

In view of the relatively poor resolution of scintillation counters with ; respect to gamma quanta with energies below the 100-kev level, the soft portion ; of the spectrum was investigated with high-resolution proportional counters. A ; singlechannel spectrometer was used; its gamma detector consisted of a 200-mm ; high and 34-mm diameter chamber filled with Xe under a pressure

B. M. Kolesov; Yu. P. Lyubavin; A. K. Ovchinnikov

1963-01-01

381

Smart poly(oligo(propylene glycol) methacrylate) hydrogel prepared by gamma radiation  

NASA Astrophysics Data System (ADS)

The synthesis of poly(oligo(propylene glycol) methacrylate) (POPGMA) from functionalised oligo(propylene glycol) methacrylate (OPGMA) monomers by gamma radiation-induced radical polymerisation is reported for the first time; POPGMA homopolymeric hydrogel with oligo(propylene glycol) (OPG) pendant chains, as a non-linear PPGMA-analogue, was synthesised from an monomer-solvent (OPGMA375-water/ethanol) mixture at different irradiation doses (5, 10, 25, and 40 kGy). Determination of the gel fraction was conducted after synthesis. The swelling properties of the POPGMA hydrogel were preliminarily investigated over wide pH (2.2-9.0) and temperature (4-70 °C) ranges. Additional characterisation of structure and properties was conducted by UV-vis and Fourier transform infrared (FTIR) spectroscopy as well as by differential scanning calorimetry (DSC). In order to evaluate the potential for biomedical applications, biocompatibility (cytocompatibility and haemolytic activity) studies were performed as well. Sol-gel conversion was relatively high for all irradiation doses, indicating radiation-induced synthesis as a good method for fabricating this hydrogel. Thermoresponsiveness and variations in swelling capacity as a result of thermosensitive OPG pendant chains with a lower critical solution temperature (LCST) were mainly observed below room temperature; thus, the volume phase transition temperature (VPTT) of POPGMA homopolymeric hydrogel is about 15 °C. Furthermore, POPGMA has satisfactory biocompatibility. The results indicate that the hydrogels with propylene glycol pendant chains can be easily prepared by gamma radiation and have potential for different applications as smart and biocompatible polymers.

Suljovrujic, E.; Micic, M.

2015-01-01

382

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

383

Measurement of Branching Fractions in Radiative BDecays to eta K gamma and Search for B Decays to eta' K gamma  

SciTech Connect

The authors present measurements of the B {yields} {eta}K{gamma} branching fractions and upper limits for the B {yields} {eta}'K{gamma} branching fractions. For B{sup +} {yields} {eta}K{sup +}{gamma} they also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents 232 x 10{sup 6} produced B{bar B} pairs. The results for branching fractions and upper limits at 90% C.L. in units of 10{sup -6} are: {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = 11.3{sub -2.6}{sup +2.8} {+-} 0.6, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = 10.0 {+-} 1.3 {+-} 0.5, {Beta}(B{sup 0} {yields} {eta}'K{sup 0}{gamma}) < 6.6, {Beta}(B{sup +} {yields} {eta}'K{sup +}{gamma}) < 4.2. The charge asymmetry in the decay B{sup +} {yields} {eta}K{sup +}{gamma} is {Alpha}{sub ch} = -0.09 {+-} 0.12 {+-} 0.01. The first errors are statistical and the second systematic.

Aubert, B.

2006-03-31

384

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

385

Mechanism of action for anti-radiation vaccine in reducing the biological impact of high-dose gamma irradiation  

NASA Astrophysics Data System (ADS)

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 high-dose gamma irradiation. These radiation-induced toxins, which we have named specific radiation determinants (SRD), were generated in the irradiated tissues and then 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 naïve 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 they 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.

386

Outdoor radiofrequency radiation levels in the West Bank-Palestine.  

PubMed

This work presents the results of exposure levels to radio frequency (RF) emission from different sources in the environment of the West Bank-Palestine. These RF emitters include FM and TV broadcasting stations and mobile phone base stations. Power densities were measured at 65 locations distributed over the West Bank area. These locations include mainly centres of the major cities. Also a 24 h activity level was investigated for a mobile phone base station to determine the maximum activity level for this kind of RF emitters. All measurements were conducted at a height of 1.7 m above ground level using hand held Narda SRM 3000 spectrum analyzer with isotropic antenna capable of collecting RF signals in the frequency band from 75 MHz to 3 GHz. The average value of power density resulted from FM radio broadcasting in all investigated locations was 0.148 ?W cm(-2), from TV broadcasting was 0.007 ?W cm(-2) and from mobile phone base station was 0.089 ?W cm(-2). The maximum total exposure evaluated at any location was 3.86 ?W cm(-2). The corresponding exposure quotient calculated for this site was 0.02. This value is well below unity indicating compliance with the International Commission on non-ionising Radiation protection guidelines. Contributions from all relevant RF sources to the total exposure were evaluated and found to be ~62 % from FM radio, 3 % for TV broadcasting and 35 % from mobile phone base stations. The average total exposure from all investigated RF sources was 0.37 ?W cm(-2). PMID:21835841

Lahham, Adnan; Hammash, Alaa

2012-05-01

387

Measuring Neutrons and Gamma Rays on Mars - The Mars Science Laboratory Radiation Assessment Detector MSL/RAD  

NASA Astrophysics Data System (ADS)

The Mars Science Laboratory (MSL) missions Radiation Assessment Detector (RAD) will measure the radiation environment on the Martian surface. One of the difficult measurements is that of the neutral radiation component consisting of neutrons and gamma rays. Different from Earth, this neutral component contributes substantially to the total dose on the planetary surface, principally because the Martian atmosphere is so thin. We will present methods to invert neutral particle data acquired with MSL's RAD instrument and compare them with calibration data. While the agreement is good for neutrons from a calibration beam in a forward model, more work is required for omnidirectional neutrons with unknown spectral properties using other inversion techniques. We expect an asymmetry in fluxes from soil and sky for neutrons. Preliminary simulation results show a different behavior for gamma rays. Therefore, models of the IRF are likely to require additional inputs about the radiation environement.

Martin, Cesar; Kortmann, Onno; Boehm, Eckart; Boettcher, Stephan; Kharytonov, Alexander; Ehresmann, Bent; Wimmer-Schweingruber, Robert F.; Hassler, Donald M.; Zeitlin, Cary

2010-05-01

388

Numerical study of Gamma-Ray Bursts: Relativistic radiation hydrodynamics simulation  

NASA Astrophysics Data System (ADS)

Special relativistic physics plays an important role in many celestial phenomena such as Gamma-Ray Bursts (GRBs) and Active Galactic Nuclei (AGNs). During the past decade, many efforts have been made to simulate these phenomena by developing relativistic hydrodynamics codes with various algorithms. A realistic simulation needs to include magnetic field and radiation which makes the computational code more complicated. For my thesis research, I have developed a relativistic radiation hydrodynamics code in 3-D Cartesian coordinates. My code was developed by using PARAMESH, the Parallel Adaptive Mesh Refinement (AMR) library which makes my code run on parallel computers with AMR. My code is composed of two parts: relativistic hydrodynamics and radiation transport. For the hydrodynamics part, a Flux Corrected Transport (FCT) algorithm was used. I adopted the recent version of FCT algorithm called LCPFCT which was developed at Naval Research Lab to solve the 1-D Newtonian hydrodynamics equations in conservation form. Extension to 3-D was done using Zalesak's multi-dimensional limiter. According to previous results comparing various relativistic hydrodynamics codes based upon different algorithms, it is generally known that a relativistic hydrodynamics code developed with the FCT algorithm does not produce as accurate results as some other codes developed with high resolution shock capturing algorithms. However, the test problems simulated with my code show that the relativistic FCT code with a modification to the diffusion and antidiffusion coefficients is capable of producing results comparable to other algorithms when it is combined with AMR. The main advantage of using the FCT algorithm is its straightforward implementation when the code is extended to the relativistic radiation hydrodynamics regime because no Riemann solver is involved. For the radiation transport part of my code, I derived the governing equation of radiation transport in the comoving frame. The advantage of using the comoving frame equation is that the fundamental properties of radiation such as emissivity, absorption and scattering can be treated in the same way as when the fluid is at rest. The structure of the comoving frame equation is similar to that of the lab frame equation except that the comoving frame equation has additional terms for radiation intensity variation over angle and energy. The comoving frame equation is discretized by the implicit finite difference method and my radiation transport code solves the difference equation by using the Bi-CGSTAB method which iteratively solves linear systems of equations. The relativistic radiation hydrodynamics code is a combination of hydrodynamics and radiation transport with suitable micro- physics. At the current version of my code, an ideal gas equation of state with local thermal equilibrium (LTE) is assumed but various microphysics can be easily implemented into the code. In this dissertation, the equations to solve and the details of the code implementation are presented with a series of verification test problems. As for the astrophysical applications, I simulated the propagation of relativistic jets in the context of GRBs and AGNs with radiation included. The results show that radiation changes the morphology and dynamics of the jet in a significant way.

Kwak, Kyujin

2007-08-01

389

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. PMID:25202453

Gurbuzer, Nurbanu; Ayhan Basturk, Zeliha

2014-01-01

390

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

391

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

392

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

393

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

394

How much can be learned from populations exposed to low levels of radiation  

Microsoft Academic Search

The assessment of health effects from low-level exposure to radiation is a matter of considerable controversy. Many of the problems in analyzing and interpreting data on populations exposed to low levels of radiation are well illustrated by a current study of the effects on mortality of occupational exposure to radiation at the Hanford plant. The conclusion drawn is that the

1984-01-01

395

Effects of gamma radiation on the Mediterranean flour moth, Ephestia kuehniella , eggs and acceptability of irradiated eggs by Trichogramma cacoeciae females  

Microsoft Academic Search

The sensitivity of the Mediterranean flour moth, Ephestia kuehniella, eggs in different stages of development to gamma irradiation was studied and the acceptability of irradiated eggs by Trichogramma cacoeciae females was examined. Eggs ranging in age from 1–24 to 49–72 h were exposed, at 24 h intervals, to gamma radiation dosages\\u000a ranging from 25 to 400 Gy and effects of gamma radiation on

M. Mansour

2010-01-01

396

Operation Upshot-Knothole. Project 29. 1. Comparison and evaluation of dosimetry methods applicable to gamma radiation, Nevada Proving Ground. Report for March-June 1953  

SciTech Connect

The three major objectives and parts of this project were to compare and evaluate the accuracy and practicality of chemical vs film and other methods of gamma dosimetry for radiations encountered under bomb conditions at sites receiving (1) either prompt- or residual-gamma exposures or mixtures of both, (2) only residualgamma radiations, either neutron induced or from fission-product fallout, and (3) mixed neutron-gamma irradiation plus correlation with biological effects.

Taplin, G.V.; Sigoloff, S.C.; Douglas, C.H.; Paglia, D.E.; Heller, C.J.

1984-10-31

397

Effectiveness of silane monomer and gamma radiation on chitosan films and PCL-based composites  

NASA Astrophysics Data System (ADS)

Chitosan films were prepared by casting from its 1% (w/w) solution. Tensile strength (TS) and tensile modulus (TM) of chitosan films were found to be 30 MPa and 450 MPa, respectively. Silane monomer (3-aminopropyl tri-methoxysilane) (0.25%, w/w) was added into the chitosan solution (1%, w/w) and films were casted. Then films were exposed to gamma radiation (5-25 kGy) and mechanical properties were investigated. It was found that at 10 kGy, the values of TS and TM were improved significantly. Silane grafted chitosan film reinforced poly(caprolactone) (PCL)-based tri-layer composites were prepared by compression molding. Silane improved interfacial adhesion between chitosan and PCL in composites. Surface of the films was investigated by scanning electron microscope (SEM) and found better morphology for silane grafted films.

Sharmin, Nusrat; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Akter, Nousin; Lacroix, Monique

2012-08-01

398

Influence of gamma radiation on the physicochemical and rheological properties of sterculia gum polysaccharides  

NASA Astrophysics Data System (ADS)

Keeping in view the influence of gamma radiation on the physiochemical properties of the polysaccharides and their importance in the food and pharmaceutical industry, in the present study attempt has been made to investigate the effects of absorbed dose on FTIR, XRD, SEMs, absorbance, pH, solubility, water absorption capacity, emulsion stability and rheology of sterculia gum. Increase in solubility and decrease in swellability of gum has been observed on increasing the absorbed dose. The emulsion stability has improved for the gum sample irradiated with total dose of 8.1±0.2 kGy. Apparent viscosity of gum solution first increased with increase in dose from 0 to 8.1±0.2 kGy than decreased with regular trends with further increase in total absorbed dose. Flow behavior of gum solution shifted to Newtonian from non-Newtonian with increasing the dose.

Singh, Baljit; Sharma, Vikrant

2013-11-01

399

Finger injury from over-exposure to an industrial gamma radiation source.  

PubMed

The aim of this paper was to report a rare cause of radionecrosis and its long-term results. Iridium-192 ((192)Ir) is commonly used for radiography as a gamma ray source to locate flaws in welds and metal components in gas and oil industry. A 38-year-old man was subjected to radiation unintentionally. One month after the exposure wounds were appeared on the second and third fingers, and they were treated by conventional wound care and hyperbaric oxygen therapy. However wounds were relapsed one year later that brought the patient to us. The wounds were treated by wound care and hyperbaric oxygen therapy. When the patient was brought to us one year later the result was interesting. The third finger's pulp (there was not any wound one year before) was contracted and one third of the distal phalanx was exposed. PMID:25249387

Sahin, Cihan; Cesur, Ceyhun; Sever, Celalettin; Eren, Fikret

2015-03-01

400

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.

401

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

402

SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications  

NASA Technical Reports Server (NTRS)

The research project "SIFTER: Scintillating Fiber Telescopes for Energetic Radiation, Gamma-Ray Applications" approved under the NASA High Energy Astrophysics Research Program. The principal investigator of the proposal was Prof. Geoffrey N. Pendleton, who is currently on extended leave from UAH. Prof. William S. Paciesas administered the grant during Dr. Pendleton's absence. The project was originally funded for one year from 6/8/2000 to 6/7/2001. Due to conflicts with other commitments by the PI, the period of performance was extended at no additional cost until 6/30/2002. The goal of this project was to study scintillating fiber pair-tracking gamma-ray telescope configurations specifically designed to perform imaging and spectroscopy in the 5 - 250 MeV energy range. The main efforts were concentrated in two areas: 1) development of tracking techniques and event reconstruction algorithms, with particular emphasis on angular resolution; and 2) investigation of coded apertures as a means to improve the instrument angular resolution at low energies.

Paciesas, William S.

2002-01-01

403

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

404

Calibration of a Dual-Energy Gamma Radiation System for Multiple Point Measurements in a Soil  

NASA Astrophysics Data System (ADS)

A method is described to experimentally determine the calibration constants for gamma-ray attenuation at multiple measurement points along a soil column as needed to simultaneously determine volumetric water content and dry bulk density at each of these points during subsequent experiments. Calibration constants for the soil solids, for both Cs-137 and Am-241, are defined as the product of the respective mass attenuation coefficients and the thickness of the soil through which the gamma radiation beam traverses. Calibration constants for water are similarly defined but include the additional term of water density. The calibration technique corrects for low energy Cs-137 pulses present in the Am-241 window and for resolving time. Although calibration constants are determined for each measurement point, the technique requires knowledge only of the initial average dry bulk density in the soil column and not at every point. The calibration constants and initial dry bulk density value for each measurement point are determined by an iteration procedure. Errors stemming from changes in the sources-soil column-detector configuration and/or pathlength when measuring at different points are therefore negated.

Hopmans, J. W.; Dane, J. H.

1986-07-01

405

Podophyllum hexandrum modulates gamma radiation-induced immunosuppression in Balb/c mice: implications in radioprotection.  

PubMed

Aqueous extract of Podophyllum hexandrum (RP-1), which has been reported to render more than 82% survival against whole body lethal (10 Gy) gamma-irradiation in mice, was further investigated for its immunomodulatory potential. In this study, no significant change could be scored in peritoneal macrophages survival up to 8th day after whole body irradiation. RP-1 treatment (200 mg/kg body weight, i.p.) alone or 2 h before whole body irradiation enhanced macrophage survival significantly (p<0.05) as compared to irradiated control mice. In irradiated animals, there was significant (p<0.01) reduction in splenocyte survival and proliferation as revealed by 3H-TdR method. RP-1 treatment (200 mg/kg) alone or 2 h before irradiation countered the decrease in survival of splenocytes and proliferation significantly (p<0.05) as compared to irradiated control group. Whole body irradiation also significantly (p<0.05) reduced the population of CD4+ and CD8+ T cells and bone marrow GM-CFU at 24 h and 72 h post-irradiation intervals, respectively, as compared to unirradiated control. RP-1 treatment 2 h before whole body irradiation countered the decrease in CD4+ and CD8+ T cells populations and CGM-CFU. Nitric oxide free radicals generation was enhanced significantly (p<0.05) in the supernatant of peritoneal macrophage cultures exposed to 2 Gy gamma radiation ex vivo in comparison to unirradiated control, which was reduced by pre-irradiation (-2 h) administration of RP-1. Whole body irradiation (10 Gy) also reduced the serum titres of IL-3, IL-1 and various IgG isotypes observed at different post-irradiation time interval. RP-1 treatment alone or before whole body irradiation countered radiation induced decrease in the titre of IL-1, IL-3 and IgG's in the serum of mice. These findings indicate immunostimulatory potential of RP-1. PMID:17029008

Goel, H C; Prakash, H; Ali, A; Bala, M

2007-01-01

406

Combination of {gamma}-radiation antagonizes the cytotoxic effects of vincristine and vinblastine on both mitotic arrest and apoptosis  

SciTech Connect

Purpose: Combination therapy with different modalities is a common practice in the treatment of cancer. The promising clinical profile of vincristine and vinblastine has promoted considerable interest in combining these vinca alkaloids with radiation therapy to treat a variety of solid tumors. However, the therapeutic efficacy and the interaction between the vinca alkaloids with radiation is not entirely clear. In this study, we assessed the potential interactions in the combination of vincristine or vinblastine with {gamma}-radiation against human tumor cells in vitro. Methods and materials: Vincristine or vinblastine and {gamma}-radiation were administrated at three different sequences designed as preradiated, coradiated, and postradiated combinations in human breast cancer cells and human epidermoid carcinoma cells. The cytotoxic interactions and mutual influences between these two modalities were analyzed by a series of assays including cytotoxic, morphologic, and biochemical examinations. Results: Our results showed that the combination of these two modalities did not produce any synergistic or additive effects. Instead, the clonogenic assays showed the survival rates of these combinations were increased up to 2.17-fold and 2.7-fold, respectively, of those treated with vincristine or vinblastine alone (p < 0.01). DNA fragmentation, T{alpha}T-mediated dUTP nick end labeling (TUNEL) assay, and flow cytometric assays also showed that the combination of {gamma}-radiation significantly interfered with the ability of these vinca alkaloids to induce apoptosis. Further analyses indicated that addition of {gamma}-radiation resulted in cell cycle arrest at the G{sub 2} phase, which subsequently prevented the mitotic arrest induced by vincristine or vinblastine. In addition, biochemical examinations revealed that {gamma}-radiation regulated p34{sup cdc2}/cyclin B1 and survivin, and inhibited I{kappa}B{alpha} degradation and bcl-2 phosphorylation. Conclusions: These results suggest that {gamma}-radiation might specifically block the cell cycle at the G{sub 2} phase, which in turn interferes with the cytotoxic effects of vincristine or vinblastine on mitotic arrest and apoptosis. Thereby, it eventually results in an antagonistic interaction between these two modalities. This finding may be implicated in the clinical application of combination therapy of vinca alkaloids and radiation.

Sui, Meihua [Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC (United States); Fan Weimin [Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC (United States)]. E-mail: fanw@musc.edu

2005-03-15

407

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

408

Effect of fast neutron, gamma-ray and combined radiations on the thermal decomposition of ammonium perchlorate single crystals  

NASA Technical Reports Server (NTRS)

The thermal decomposition kinetics have been determined for ammonium perchlorate crystals subjected to a fast neutron irradiation or to a fast neutron irradiation followed by a gamma-ray irradiation. Qualitatively, the radiation induced changes are similar to those obtained in this and in previous studies, with samples exposed only to gamma rays. The induction period is shortened and the rate constants, obtained from an Avrami-Erofeyev kinetic analysis, are modified. The acceleratory period constant increases and the decay period constant decreases. When compared on an equal deposited energy basis, the fast neutron induced changes are appreciably larger than the gamma-ray induced changes. Some, or all, of the fast neutron induced effects might be attributable to the introduction of localized regions of concentrated radiation damage ('spikes') by lattice atom recoils which become thermal decomposition sites when the crystals are heated.

Herley, P. J.; Wang, C. S.; Varsi, G.; Levy, P. W.

1974-01-01

409

Transport and noise properties of Si nanowire channels with different lengths before and after gamma radiation treatment  

NASA Astrophysics Data System (ADS)

The transport properties of Si nanowire (NW) structures fabricated on the basis of silicon on insulator (SOI) wafers were studied using noise spectroscopy before and after treatment with small doses of gamma radiation. The total resistance obtained from the I-V characteristics of Si NW structures scaled perfectly with length. Normalized flicker noise demonstrated 1/L2 dependence, which is a characteristic of dominant noise contribution from near-contact regions. The behavior changed to 1/L dependence after a small dose (1×104 Gy) of gamma radiation treatment. Comparison of the random telegraph signal (RTS) noise parameters in the samples with small lengths before and after the treatment revealed a decrease in RTS amplitude and a shift to a lower frequency range after gamma irradiation. These results confirmed that the main changes in the samples were related to strain relaxation near-contact regions. In addition, such treatment resulted in a considerable decrease in the scattering data of device parameters.

Li, Jing; Vitusevich, Svetlana; Petrychuk, Mykhailo; Pud, Sergii; Sydoruk, Viktor; Danilchenko, Boris; Offenhäusser, Andreas

2013-12-01

410

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 ...

411

Sensitivity of the SREM RADFET dosimeters for STRV-1C to various proton and gamma radiation environments  

Microsoft Academic Search

The Standard Radiation Environment Monitor (SREM) was designed in a cooperation between ESA-ESTEC, PSI and Contraves Space-the manufacturer. The monitor detects cosmic particles using 3 direction sensitive Si detectors. Total dose measurement is performed with internal and external RADFETs located at selected positions on the satellite. Their sensitivity towards protons and gammas was characterised for various energies, dose rates and

W. Hajdas; J. Bialkowski; U. Wyser; L. Adams; A. Mohammadazdeh; R. Nickson; B. O'Connell

1999-01-01

412

The Australasian Radiation Protection Society's Position Statement on Risks from Low Levels of Ionizing Radiation  

PubMed Central

Controversy continues on whether or not ionizing radiation is harmful at low doses, with unresolved scientific uncertainty about effects below a few tens of millisieverts. To settle what regulatory controls should apply in this dose region, an assumption has to be made relating dose to the possibility of harm or benefit. The position of the Australasian Radiation Protection Society on this matter is set out in a statement adopted by the Society in 2005. Its salient features are: •There is insufficient evidence to establish a dose-effect relationship for doses that are less than a few tens of millisieverts in a year. A linear extrapolation from higher dose levels should be assumed only for the purpose of applying regulatory controls.• Estimates of collective dose arising from individual doses that are less than some tens of millisieverts in a year should not be used to predict numbers of fatal cancers.•The risk to an individual of doses significantly less than 100 microsieverts in a year is so small, if it exists at all, that regulatory requirements to control exposure at this level are not warranted. PMID:18648567

Higson, Donald

2007-01-01

413

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

414

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

415

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

416

The diffuse galactic gamma radiation: The Compton contribution and component separation by energy interval and galactic coordinates  

NASA Technical Reports Server (NTRS)

The radiation to be expected from cosmic ray interactions with matter and photons was examined. Particular emphasis is placed on the Compton emission. Both the photon density in and near the visible region and that in the region are deduced from the estimates of the emission functions throughout the Galaxy. The blackbody radiation is also included in the estimate of the total Compton emission. The result suggests that the gamma ray Compton radiation from cosmic ray ineractions with galactic visible and infrared photons is substantially larger than previously believed.

Kniffen, D. A.; Fichtel, C.

1981-01-01

417

Radiation Exposure During Head Repositioning With the Automatic Positioning System for Gamma Knife Radiosurgery  

SciTech Connect

Purpose: To measure radiation exposure to a patient during head repositioning with the automatic positioning system (APS) for Gamma Knife radiosurgery. Methods and Materials: A 16-cm diameter spherical solid phantom, provided by the manufacturer, was mounted to the APS unit using a custom-made holder. A small-volume ionization chamber (0.07-cm{sup 3} volume) was placed at the center of the phantom. We recorded the temporal variation of ionization current during the entire treatment. Measurements were made for 3 test cases and 7 clinical cases. Results: The average transit time between successive shots, during which the APS unit was moving the phantom for repositioning the shot coordinates, was 20.5 s for 9 cases. The average dose rate, which was measured at the center of the phantom and at a point outside the shot location, was 0.36 {+-} 0.09 cGy/min when the beam output was approximately 3.03 Gy/min for the 18-mm collimator helmet. Hence, the additional intracranial radiation dose during the APS-driven head repositioning between two successive shots (or APS transit dose) was 0.12 {+-} 0.050 cGy. The APS transit dose was independent of the helmet size and the position of shots within the phantom relative to the measurement point. Conclusion: The head repositioning with the APS system adds a small but not negligible dose to the dose expected for the manual repositioning method.

Watanabe, Yoichi [Department of Therapeutic Radiology, University of Minnesota, Minneapolis, MN (United States)]. E-mail: watan016@umn.edu; Gerbi, Bruce J. [Department of Therapeutic Radiology, University of Minnesota, Minneapolis, MN (United States)

2007-07-15

418

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

419

Measurement of Cerenkov Radiation Induced by the Gamma-Rays of Co-60 Therapy Units Using Wavelength Shifting Fiber  

PubMed Central

In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%. PMID:24755521

Jang, Kyoung Won; Shin, Sang Hun; Kim, Seon Geun; Kim, Jae Seok; Yoo, Wook Jae; Ji, Young Hoon; Lee, Bongsoo

2014-01-01

420

Measurement of Cerenkov radiation induced by the gamma-rays of Co-60 therapy units using wavelength shifting fiber.  

PubMed

In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%. PMID:24755521

Jang, Kyoung Won; Shin, Sang Hun; Kim, Seon Geun; Kim, Jae Seok; Yoo, Wook Jae; Ji, Young Hoon; Lee, Bongsoo

2014-01-01

421

Detection of high-energy gamma radiation from quasar 3C 279 by the EGRET telescope on the Compton Gamma Ray Observatory  

NASA Technical Reports Server (NTRS)

Intense gamma radiation has been observed from the direction of the quasar 3C 279 throughout the energy range from 30 MeV to over 5 GeV by the Energetic Gamma Ray Experiment Telescope (EGRET) during the period June 15-28, 1991. Its spectrum is well represented by a photon differential power-law exponent of 2.0 +/- 0.1, with a photon intensity above 100 MeV of (2.8 +/- 0.4) x 10 exp -6/sq cm s. For E is greater than 100 MeV, the 2-sigma upper limits were 1.0 x 10 exp -6/sq cm s in 1973 from the SAS 2 observations and 0.3 x 10 exp -6/sq cm s for the combined 1976, 1978, and 1980 COS B observations. Hence, there has been a large increase in high-energy gamma-ray intensity relative to the earlier times, as there has been in the radio, infrared, optical, and X-ray ranges. This source is the most distant and by far the most luminous gamma-ray source yet detected.

Hartman, R. C.; Bertsch, D. L.; Fichtel, C. E.; Hunter, S. D.; Kwok, P. W.; Thompson, D. J.; Mattox, J. R.; Kanbach, G.; Nel, H. I.; Sreekumar, P.

1992-01-01

422

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 depresse