WorldWideScience

Sample records for alpha radiation effectively

  1. Relative biological effectiveness if alpha radiation for human lung exposure

    International Nuclear Information System (INIS)

    Yarmoshenko, I.; Kirdin, I.; Zhukovsky, M.

    2006-01-01

    Full text of publication follows: The concept of RBE, which introduced by ICRP and ICRU about 50 years ago to compare biological effects of ionizing radiation of different types, still continues to be the essential element of current and projected radiation protection systems in terms of deriving quantities (quality factor and radiation weighting factor). For example, RBE for the stochastic effects induction has to be considered for appropriate radiation weighting of the absorbed dose while estimating equivalent dose. Simulation of lung cancer radiation risk for the cases of inhalation of radon progeny and incorporation of plutonium in lung in comparison with external reference radiation allows assessment of RBE for alpha-radiation. Specific radiation risk models were developed by results of the direct epidemiological studies and used for such simulation. Simulation included published risk models for nuclear workers of the Mayak facilities in the former Soviet Union exposed to incorporated plutonium (Kreisheimer et al., 2003; Gilbert et al., 2004) and underground miners exposed to radon progenies (BEIR VI, 1999). Additionally lung cancer risk model was developed for a case of population indoor radon exposure. Lung cancer risk related to external exposure is estimated using the risk model develop ed using data of Life Span Study of Japanese atomic bomb survivors. By results of lifetime lung cancer risk simulation using Monte Carlo approach estimated median value of RBE in case of indoor radon exposure is 1.5 (with 90% range 0.4 to 7). In case of the two models developed by BEIR VI for lung cancer risk due to radon exposure in underground miners the median values of RBE are 2.1 and 4.4 (with 90% ranges 0.3 to 17 and 0.7 to 45) respectively.Two different models for lung cancer risk related to plutonium exposure resulted in close estimates of RBE: median value of 12 and 13 (with 90% range 4 to 104 and 4 to 136) respectively. Considerable discrepancy between RBE

  2. Risk estimates for the health effects of alpha radiation

    International Nuclear Information System (INIS)

    Thomas, D.C.; McNeill, K.G.

    1981-09-01

    This report provides risk estimates for various health effects of alpha radiation. Human and animal data have been used to characterize the shapes of dose-response relations and the effects of various modifying factors, but quantitative risk estimates are based solely on human data: for lung cancer, on miners in the Colorado plateau, Czechoslovakia, Sweden, Ontario and Newfoundland; for bone and head cancers, on radium dial painters and radium-injected patients. Slopes of dose-response relations for lung cancer show a tendency to decrease with increasing dose. Linear extrapolation is unlikely to underestimate the excess risk at low doses by more than a factor of l.5. Under the linear cell-killing model, our best estimate

  3. Damage radiation alpha effects in sintered waste form

    International Nuclear Information System (INIS)

    Messi de Bernasconi, Norma B.; Prado, Miguel O.; Bevilacqua, Arturo M.; Arribere, Maria; Heredia, Arturo D.; Sanfilippo, Miguel

    1999-01-01

    We have subjected the borosilicate glass to thermal neutron irradiation in a reactor, with an accumulated fluence equivalent to approximately E3, E4, E5, y E6 years of waste disposal. We considered the following potential effects of accumulated alpha decay: a) Changes in the density; b) Changes in the dissolution rates; c) Changes in the microstructure of the sintered glass. (author)

  4. Biological effect of focal alpha radiation on the hamster lung

    International Nuclear Information System (INIS)

    Smith, D.M.; Anderson, E.C.; Prine, J.R.; Holland, L.M.; Richmond, C.R.

    1975-11-01

    Monodispersed 10-μm diameter ZrO 2 ceramic microspheres, containing varying amounts of 239 PuO 2 or 238 PuO 2 , were injected into the jugular vein of 100-day-old Syrian hamsters. These biologically inert microspheres lodged subsequently in pulmonary capillaries and remained static in position throughout the life span of the animals with no discernible inflammatory response. The numbers of microspheres injected ranged from 2000 to 10,000 and the specific activity from 0 to 59 pCi/sphere so that the lung burdens were 0 to 354 nCi/animal. At these numbers, each plutonium-laden microsphere served as an independent, focal source of alpha radiation. No consistent alteration of life spans post-exposure was seen in the experimental hamsters compared to controls. Pulmonary tissue responses were minimal with only 0.5 percent of the animals given Pu/ZrO 2 microspheres ultimately developing primary tumors of the lung. No unexpected gross or histologic lesion were found in other major body tissues

  5. Biological effects of alpha radiation on a human population

    International Nuclear Information System (INIS)

    Thorleifson, E.M.; Marro, L.; Tracy, B.L.; Wilkinson, D.; Segura, T.M.; Prud'homme-Lalonde, L.; Leach, K.; Ford, B.N.

    2003-01-01

    Full text: In the environment, natural and man-made sources of radioactive material can become integrated into the food chain. Polonium-210 is a significant source of radiation exposure to caribou and to northern human populations who are dependent on caribou for a major portion of their meat supply. Previous work has shown that humans consuming caribou meat containing measurable quantities of polonium-210 can incorporate a substantial fraction of the radionuclide (Thomas et. al.). Conventional chromosome aberration analysis of blood samples collected from 40 individuals who routinely consumed caribou meat was performed to measure genetic damage from the ingested radioactive material. At least 500 metaphase spreads were analysed for each of 39 individuals. Radiation-specific chromosomal aberrations such as dicentrics and rings were scored and their frequencies were compared to the range of aberrations observed in non-caribou consuming populations. This study was designed to address the possible impact of environmental polonium-210 on background radiation health effects in humans

  6. Relative biological effectiveness (RBE) of alpha radiation in cultured porcine aortic endothelial cells.

    Science.gov (United States)

    Thomas, Patricia; Tracy, Bliss; Ping, Tilly; Baweja, Anar; Wickstrom, Mark; Sidhu, Narinder; Hiebert, Linda

    2007-03-01

    Northern peoples can receive elevated radiation doses (1- 10 mSv/y) from transfer of polonium-210 (210Po) through the lichen-caribou-human food chain. Ingested 210Po is primarily blood-borne and thus many of its short range alpha particles irradiate the endothelial cells lining the blood vessels. The relative biological effectiveness (RBE) of alpha particles vs. x-rays was examined in porcine aortic endothelial cells as a surrogate for understanding what might happen to human endothelial cells in northern populations consuming traditional foods. Cultured porcine aortic endothelial cells were exposed to x-ray and 210Po alpha particle radiation. Alpha irradiation was applied to the cell cultures internally via the culture medium and externally, using thin-bottomed culture dishes. The results given here are based on the external irradiation method, which was found to be more reliable. Dose-response curves were compared for four lethal endpoints (cell viability, live cell fraction, release of lactate dehydrogenase [LDH] and clonogenic survival) to determine the relative biological effectiveness (RBE) of alpha radiation. The alpha RBE for porcine cells varied from 1.6-21, depending on the endpoint: 21.2+/-4.5 for cell viability, 12.9+/-2.7 for decrease in live cell number, 5.3+/-0.4 for LDH release to the medium but only 1.6 +/-0.1 for clonogenic survival. The low RBE of 1.6 was due to x-ray hypersensitivity of endothelial cells at low doses.

  7. Effect of polonium alpha-radiation on aqueous solutions (the history of French and Russian studies)

    International Nuclear Information System (INIS)

    Vladimirova, M.V.

    1998-01-01

    Since Pierre and Marie Curie's discovery of polonium and radium the effect of their radiation on chemical systems was noted. This gave rise to a new science - radiation chemistry. Systematic studies of radiation effects go back to the mid-1940s. The effect of gamma and x radiation was studied most, while only M. Curie's laboratory in France was concerned with alpha emitting polonium and radon. M. Haissinsky, M. Lefort, P. Bonet-Marry, M. Anta pioneered this activity. Radon was soon abandoned in favour of polonium recovered from RaD. With its short half-life, polonium is an ideal emitter which at its low content by weight produces a highly intensive radiation. French scientists determined radiation yields of H 2 , O 2 , H 2 O 2 and that of water radiolytic decomposition, G[-H 2 O]. The latter was found to be equal to 3.5 molecule/100 eV and much less than that from gamma radiolysis (4.2 molecule/100 eV). It should be noted that the polonium recovered from RaD contained a variety of impurities influencing the yield of radiolysis products formed. From the outset of her study in 1957, the author of this paper used the purest polonium recovered from reactor-irradiated Bi-209. This made it possible to define the yields from alpha radiolysis of various aqueous solutions more exactly. Relying on the J. Pucheault hypothesis concerning the decomposition of molecular radiolysis products in heavy particle tracks, author's efforts were directed toward the quantification of initial radiolysis yields. Special experiments have shown that G[-H 2 O] is much the same from alpha and gamma radiolysis (around 4.2 molecule/100eV). The author had the good luck to discuss her results with Pr. M. Haissinsky from Laboratory Curie. (author)

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

    International Nuclear Information System (INIS)

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

    1990-01-01

    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

  9. Trans-generational effects induced by alpha and gamma ionizing radiations at Daphnia magna

    International Nuclear Information System (INIS)

    Parisot, Florian

    2015-01-01

    Anthropogenic activities related to the nuclear industry contribute to continuous discharges of radionuclides into terrestrial and aquatic ecosystems. Over the past decades, the ecological risk of ionizing radiation has become a growing public, regulatory and scientific concern for ecosystems protection. Until recently, only few studies focus on exposure situations at low doses of irradiation, although these situations are representative of realistic environmental conditions. Understanding how ionizing radiation affects species over several generations and at various levels of biological organization is a major research goal in radioecology. The aim of this PhD was to bring new knowledge on the effects of ionizing radiation during a multi-generational expose of the aquatic invertebrate, Daphnia magna. A two-step strategy was implemented. First, an external gamma radiation at environmentally relevant dose rates was performed on D. magna over three successive generations (F0, F1 and F2). The objective of this experiment was to examine whether low dose rates of radiation induced increasing effects on survival, growth and reproduction of daphnids over generations and to test a possible accumulation and transmission of DNA alterations from adults to offspring. Results showed an accumulation and a transmission of DNA alterations over generations, together with an increase in effect severity on growth and reproduction from generation F0 to generation F2. Transiently more efficient DNA repair leading to some recovery at the organism level was suggested in generation F1. Second, data from the external gamma irradiation and those from an earlier study of internal alpha contamination were analyzed with DEBtox models (Dynamic Energy Budget applied to toxicology), to identify and compare the causes of the trans-generational increase in effect severity between the two types of radiation. In each case, two distinct metabolic modes of action were necessary to explain effects on

  10. Differential Effects of Alpha-Particle Radiation and X-Irradiation on Genes Associated with Apoptosis

    International Nuclear Information System (INIS)

    Chauhan, V.; Howland, M.; Chen, J.; Kutzner, B.; Wilkins, R.C.

    2011-01-01

    This study examined differential effects of alpha-(α) particle radiation and X-rays on apoptosis and associated changes in gene expression. Human monocytic cells were exposed to a-particle radiation and X-rays from 0 to 1.5 Gy. Four days postexposure, cell death was measured by flow cytometry and 84 genes related to apoptosis were analyzed using real-time PCR. On average, 33% of the cells were apoptotic at 1.5 Gy of a-particle radiation. Transcript profiling showed statistical expression of 15 genes at all three doses tested. Cells exposed to X-rays were <5% apoptotic at ∼1.5 Gy and induced less than a 2-fold expression in 6 apoptotic genes at the higher doses of radiation. Among these 6 genes, Fas and TNF-α were common to the α-irradiated cells. This data suggests that α-particle radiation initiates cell death by TNF-a and Fas activation and through intermediate signalling mediators that are distinct from X-irradiated cells

  11. The radiolysis of CMPO: effects of acid, metal complexation and alpha vs. gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bruce J. Mincher; Stephen P. Mezyk; Gary S. Groenewold

    2016-05-01

    Abstract The group actinide/lanthanide complexing agent octylphenylcarbamoylmethyl phosphine oxide (CMPO) has been examined for its radiation stability by measuring the kinetics of its reactions with free radicals in both the aqueous and organic phases for the free and metal-complexed ligand, identifying its degradation products for both alpha and gamma irradiation, measuring the effects on solvent extraction performance, and measuring the G-values for its degradation under various conditions. This includes the G-values for CMPO in the absence of, and in contact with the acidic aqueous phase, where it is shown that the acidic aqueous phase provides radio-protection for this ligand. It was found that both solvent and metal complexation affect the kinetics of the reaction of the •NO3 radical, a product of HNO3 radiolysis, with CMPO. For example, CMPO complexed with lanthanides has a rate constant for this reaction an order of magnitude higher than for the free ligand, and the reaction for the free ligand in the organic phase is about three times faster than in the aqueous phase. In steady state radiolysis kinetics it was determined that HNO3, although not NO3- anion, provides radio-protection to CMPO, with the G-value for its degradation decreasing with increasing acidity, until it was almost completely suppressed by irradiation in contact with 5 M HNO3. The same degradation products were produced by irradiation with alpha and gamma-sources, except that the relative abundances of these products varied. For example, the product of C-C bond scission was produced only in low amounts for gamma-radiolysis, but it was an important product for samples irradiated with a He ion beam. These results are compared to the new data appearing in the literature on DGA radiolysis, since CMPO and the DGAs both contain the amide functional group.

  12. Effects of alpha radiation on hardness and toughness of the borosilicate glass applied to radioactive wastes immobilization

    International Nuclear Information System (INIS)

    Prado, Miguel Oscar; Bernasconi, Norma B. Messi de; Bevilacqua, Arturo Miguel; Arribere, Maria Angelica; Heredia, Arturo D.; Sanfilippo, Miguel

    1999-01-01

    Borosilicate german glass SG7 samples, obtained by frit sintering, were irradiated with different fluences of thermal neutrons in the nucleus of a nuclear reactor. The nuclear reaction 10 B(n,α) 7 Li, where the 10 B isotope is one of the natural glass components, was used to generate alpha particles throughout the glass volume. The maximum alpha disintegration per unit volume achieved was equivalent to that accumulated in a borosilicate glass with nuclear wastes after 3.8 million years. Through Vickers indentations values for microhardness, stress for 50% fracture probability (Weibull statistics) and estimation of the toughness were obtained as a function of alpha radiation dose. Two counterbalanced effects were found: that due to the disorder created by the alpha particles in the glass and that due to the annealing during irradiation (temperature below 240 deg C). Considering the alpha radiation effect, glasses tend decrease Vickers hardness, and to increase thr 50% fracture probability stress with the dose increase. (author)

  13. Effects of alpha radiation on plutonium incorporated in dosimetric materials by ESR studies

    International Nuclear Information System (INIS)

    Bhide, M.K.; Kadam, R.M.; Mohapatra, Manoj; Godbole, S.V.

    2007-01-01

    The in situ alpha irradiation effects of some ESR dosimetric materials namely alanine, 2-methyl alanine and ammonium tartrate were studied by incorporating 1% plutonium by weight in them. The radical intensity was monitored as a function of alpha dose. It was found that in the dose region 1-35 kGy ammonium tartrate showed better signal intensity, linearity and dose response as compared to the other materials. This was attributed to the single radical produced in case of the tartrate giving a sharp spectrum and the fast relaxation times owing to less saturation of ESR signals. (author)

  14. The effects of intense gamma-irradiation on the alpha-particle response of silicon carbide semiconductor radiation detectors

    International Nuclear Information System (INIS)

    Ruddy, Frank H.; Seidel, John G.

    2007-01-01

    Silicon Carbide (SiC) semiconductor radiation detectors are being developed for alpha-particle, X-ray and Gamma-ray, and fast-neutron energy spectrometry. SiC detectors have been operated at temperatures up to 306 deg. C and have also been found to be highly resistant to the radiation effects of fast-neutron and charged-particle bombardments. In the present work, the alpha-particle response of a SiC detector based on a Schottky diode design has been carefully monitored as a function of 137 Cs gamma-ray exposure. The changes in response have been found to be negligible for gamma exposures up to and including 5.4 MGy, and irradiations to higher doses are in progress

  15. Effect of alpha and gamma radiation on the near-field chemistry and geochemistry of high-level waste packages

    International Nuclear Information System (INIS)

    Reed, D.T.

    1985-12-01

    Ionizing radiation can potentially alter geochemical and chemical processes in a geologic system. These effects can either enhance or reduce the performance of the waste package in a deep geologic repository. Current indications are that, in a repository located in basalt, ionizing radiation significantly affects geochemical/chemical processes but does not appear to significantly affect factors important to the long-term performance of the repository. The experimental results presented in this paper were obtained as part of an ongoing effort by the Basalt Waste Isolation Project to determine the effect of ionizing radiation on chemical and geochemical processes in the environment of the waste package. Gamma radiolysis experiments were done by subjecting samples of synthetic basalt groundwater in the presence of various waste package components (basalt/packing/low-carbon steel) to high levels of gamma radiation from a 60 Co source. Post-irradiation analysis was done on the gas, liquid, and solid components of the basalt system. The results obtained are important in evaluating waste package performance during the containment period. The effect of alpha radiation on the basalt groundwater system in the presence of waste package components is important in evaluating waste package performance during the isolation period. The experimental work in this area is in a very preliminary stage. Results from two experiments are reported. 9 refs., 4 figs., 7 tabs

  16. Differential modulation of a radiation-induced bystander effect in glioblastoma cells by pifithrin-alpha and wortmannin

    Energy Technology Data Exchange (ETDEWEB)

    Shao Chunlin, E-mail: clshao@shmu.edu.c [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Zhang Jianghong [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Prise, Kevin M. [Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Lisburn Road, Belfast BT9 7AB (United Kingdom)

    2010-03-15

    The implication of radiation-induced bystander effect (RIBE) for both radiation protection and radiotherapy has attracted significant attention, but a key question is how to modulate the RIBE. The present study found that, when a fraction of glioblastoma cells in T98G population were individually targeted with precise helium particles through their nucleus, micronucleus (MN) were induced and its yield increased non-linearly with radiation dose. After co-culturing with irradiated cells, additional MN could be induced in the non-irradiated bystander cells and its yield was independent of irradiation dose, giving direct evidence of a RIBE. Further results showed that the RIBE could be eliminated by pifithrin-alpha (p53 inhibitor) but enhanced by wortmannin (PI3K inhibitor). Moreover, it was found that nitric oxide (NO) contributed to this RIBE, and the levels of NO of both irradiated cells and bystander cells could be extensively diminished by pifithrin-alpha but insignificantly reduced by wortmannin. Our results indicate that RIBE can be modulated by p53 and PI3K through a NO-dependent and NO-independent pathway, respectively.

  17. Alpha radiation and in-pile annealing effects on the fracture properties of a sintered alumino borosilicate glass

    International Nuclear Information System (INIS)

    Bevilacqua, Arturo M.; Prado, Miguel O.; Messi de Bernasconi, Norma B.; Heredia, Arturo D.; Sanfilippo, Miguel

    1999-01-01

    The alpha radiation and the in-pile during irradiation effects on the hardness, the crack nucleation and the fracture toughness of the German alumino borosilicate glass SG7 were investigated by using the Vickers indentation. Cold pressed and sintered samples were irradiated with thermal neutrons, in the Argentine nuclear reactors RA-3 and RA-6, to produce alpha particles in the whole volume of the glass by means of the (n, alpha)-reaction with B-10. The Vickers hardness, the crack nucleation, as 50 percent fracture probability load, plotted as the Weibull's fracture probability distribution function and the fracture toughness, as critical stress intensity factor K Ic , were correlated to the four cumulative disintegration values. It was ascertained that: a) the Vickers hardness decreases from 5.6 GPa for the non-irradiated sample up to 4.7 GPa for the sample irradiated 70 h at the lower neutron flux (4.0 x 10 - sup 18 - alpha disintegration per cm - sup 3 -), b) the 50 % fracture probability load increases from 1.4 N for the non-irradiated sample up to 4.7 g for the sample irradiated 22 h at the higher flux (6.8 x 10 - sup 18 - alpha disintegration per cm - sup 3 -), and c) the stress intensity factor increases from 0.80 MPa.m - sup 1/2 - for the non irradiated sample up to 0.86 MPa.m - sup 1/2 - for the sample mentioned in b). The in-pile annealing was analyzed by comparing the crack nucleation after irradiation with data obtained by heavy ion irradiation followed by thermal annealing. Results for the SG7 glass were compared to those for soda-lime and borosilicate glasses. (author)

  18. The effects of radiation (beta/gamma and alpha) on cemented intermediate level waste

    International Nuclear Information System (INIS)

    Jones, D.V.C.; Wilding, C.R.

    1990-02-01

    A worldwide review of what has been published on the effects of radiation on cemented ILW has been carried out where properties such as composition and volume of any gas evolved/absorbed, physical properties, chemical evolution and dose rate were considered. It is clear that only a superficial knowledge of the underlying reasons for radiolytic effects exist although there is sufficient data to enable quantities of gas a function of storage time to be predicted. If long term predictions of behaviour are to be made then the understanding of basic radiation chemistry of cement grout needs to be developed in parallel with the wider study of understanding the effects at the elevated temperatures expected to be present in a repository. (author)

  19. Radiation quality and effective dose equivalent of alpha particles from radon decay products indoors: uncertainties in risk estimation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Affan, I.A. (Velindre Hospital, Whitchurch, Cardiff (United Kingdom))

    1994-01-01

    In order to make a better estimate of cancer risk due to radon the radiation quality of alpha particles emitted from the element and its daughters has been re-assessed. In particular, uncertainties in all components involved in the calculations of the effective dose E, have been investigated. This has been done in the light of the recent draft report of the ICRU on quantities and units for use in radiation protection (Allisy et al (1991) ICRU NEWS 2). On the assumption of an indoor radon concentration of 30 Bq.m[sup -3], microdose spectra have been calculated for alpha particles hitting lung cells at different depths. Then the mean quality factor Q-bar in the lung, dose equivalent H[sub T] to the lung and the effective dose have been calculated. A comparison between lung cancer risk from radon and that arising from diagnostic X rays to the chest is made. A suggestion to make the lung weighting factor w[sub T] a function of the fraction of lung cells hit is discussed. (Author).

  20. Fluorescence Quenching of Alpha-Fetoprotein by Gold Nanoparticles: Effect of Dielectric Shell on Non-Radiative Decay

    Science.gov (United States)

    Zhu, Jian; Li, Jian-Jun; Wang, A.-Qing; Chen, Yu; Zhao, Jun-Wu

    2010-09-01

    Fluorescence quenching spectrometry was applied to study the interactions between gold colloidal nanoparticles and alpha-fetoprotein (AFP). Experimental results show that the gold nanoparticles can quench the fluorescence emission of adsorbed AFP effectively. Furthermore, the intensity of fluorescence emission peak decreases monotonously with the increasing gold nanoparticles content. A mechanism based on surface plasmon resonance-induced non-radiative decay was investigated to illuminate the effect of a dielectric shell on the fluorescence quenching ability of gold nanoparticles. The calculation results show that the increasing dielectric shell thickness may improve the monochromaticity of fluorescence quenching. However, high energy transfer efficiency can be obtained within a wide wavelength band by coating a thinner dielectric shell.

  1. The alpha channeling effect

    Science.gov (United States)

    Fisch, N. J.

    2015-12-01

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  2. Study of the antioxidant effect of {alpha}-tocopherol on low-density lipoprotein peroxidation induced at low and high {gamma}-radiation dose rates

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Abdelouahed [Research Centre on Aging and Department of Medicine, University of Sherbrooke, Sherbrooke, QC, J1H 4C4 (Canada)]. E-mail: abdelouahed.khalil@usherbrooke.ca; Milochevitch, Christelle [Research Centre on Aging and Department of Medicine, University of Sherbrooke, Sherbrooke, QC, J1H 4C4 (Canada)

    2005-02-01

    It is well known that vitamin E ({alpha}-tocopherol, {alpha}-toc) is a very efficient lipid soluble antioxidant and several studies showed its beneficial action in the prevention and reduction of atherosclerosis. However, some in vitro studies suggest a prooxidant role of vitamin E, which could occur under given circumstances. This study was thus designed to investigate the antioxidant vs. prooxidant effect of vitamin E with regards to LDL peroxidation induced under different oxidative stress conditions. LDL was enriched with {alpha}-tocopherol and different {alpha}-toc/LDL ratios were studied (8.0{+-}2.5, 14.3{+-}3.0, 33.3{+-}3.7, 42.7{+-}3.5 and 48.2{+-}4.5 molecules of {alpha}-toc/LDL particle). Enriched and control LDL were oxidized by action of {sup {center_dot}}OH and O{sub 2}{sup {center_dot}}{sup -} free radicals produced by {gamma}-radiolysis at different dose rates. Susceptibility of LDL to oxidation was examined by the measure of conjugated diene and TBARS formation as well as LDL endogenous {alpha}-toc disappearance. Increasing LDL {alpha}-toc concentration reduced the LDL susceptibility to oxidation and their oxidizability. {alpha}-toc disappearance rates were comprised between 43 and 8.3x10{sup -10} M s{sup -1} and decreased with the radiation dose rate. Our results support an antioxidant role for {alpha}-tocopherol at high and low oxidative stress conditions.

  3. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

    Sand, J.; Hannuksela, V.; Toivonen, J.; Ihantola, S.; Peraejaervi, K.; Toivonen, H.

    2010-01-01

    Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

  4. Effects of Trehalose on Thermodynamic Properties of Alpha-synuclein Revealed through Synchrotron Radiation Circular Dichroism

    Directory of Open Access Journals (Sweden)

    Paolo Ruzza

    2015-05-01

    Full Text Available Many neurodegenerative diseases, including Huntington’s, Alzheimer’s and Parkinson’s diseases, are characterized by protein misfolding and aggregation. The capability of trehalose to interfere with protein misfolding and aggregation has been recently evaluated by several research groups. In the present work, we studied, by means of synchrotron radiation circular dichroism (SRCD spectroscopy, the dose-effect of trehalose on α-synuclein conformation and/or stability to probe the capability of this osmolyte to interfere with α-synuclein’s aggregation. Our study indicated that a low trehalose concentration stabilized α-synuclein folding much better than at high concentration by blocking in vitro α-synuclein’s polymerisation. These results suggested that trehalose could be associated with other drugs leading to a new approach for treating Parkinson’s and other brain-related diseases.

  5. Isotope effect in the photochemical decomposition of CO{sub 2} (ice) by Lyman-{alpha} radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Chunqing; Yates, John T. Jr. [Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2013-04-21

    The photochemical decomposition of CO{sub 2}(ice) at 75 K by Lyman-{alpha} radiation (10.2 eV) has been studied using transmission infrared spectroscopy. An isotope effect in the decomposition of the CO{sub 2} molecule in the ice has been discovered, favoring {sup 12}CO{sub 2} photodecomposition over {sup 13}CO{sub 2} by about 10%. The effect is caused by electronic energy transfer from the excited CO{sub 2} molecule to the ice matrix, which favors quenching of the heavier electronically-excited {sup 13}CO{sub 2} molecule over {sup 12}CO{sub 2}. The effect is similar to the Menzel-Gomer-Redhead isotope effect in desorption from adsorbed molecules on surfaces when electronically excited. An enhancement of the rate of formation of lattice-trapped CO and CO{sub 3} species is observed for the photolysis of the {sup 12}CO{sub 2} molecule compared to the {sup 13}CO{sub 2} molecule in the ice. Only 0.5% of the primary photoexcitation results in O-CO bond dissociation to produce trapped-CO and trapped-CO{sub 3} product molecules and the majority of the electronically-excited CO{sub 2} molecules return to the ground state. Here either vibrational relaxation occurs (majority process) or desorption of CO{sub 2} occurs (minority process) from highly vibrationally-excited CO{sub 2} molecules in the ice. The observation of the {sup 12}C/{sup 13}C isotope effect in the Lyman-{alpha} induced photodecomposition of CO{sub 2} (ice) suggests that over astronomical time scales the isotope enrichment effect may distort historical information derived from isotope ratios in space wherever photochemistry can occur.

  6. The radiolysis of CMPO: effects of acid, metal complexation and alpha vs. gamma radiation

    International Nuclear Information System (INIS)

    Mincher, B.J.; Groenewold, G.S.; Mezyk, S.P.

    2016-01-01

    The organophosphorus amide octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl phosphine oxide (CMPO) is proposed for use in fuel cycle separations as a group actinide/lanthanide extractant. Alternative compounds such as the mono-amides and diglycol amides (DGAs) proposed for actinide and/or actinide/lanthanide extraction also contain the amidic functional group, but do not contain the CMPO aromatic or phosphoryl groups. Their radiation stability is in the order mono-amides > CMPO > DGA for irradiation under similar conditions. Although they produce similar radiolysis products, the kinetics of degradation for CMPO are completely different than for the other amides. CMPO degradation occurs in a zero-order fashion, and the -G-value for the change in [CMPO] is much lower when in the presence of acid. The DGAs and mono-amides degrade with pseudo-first-order kinetics and are not protected by acidity. Possible mechanistic reasons for the differences between CMPO and the other amides are discussed, as are the effects of the diluent and metal complexation on CMPO free radical reaction rates. Finally, it is also shown that α-irradiation has much less adverse effects on CMPO degradation than β/γ irradiation, both with respect to -G-values, and radiolysis product generation. (authors)

  7. The radiolysis of CMPO: effects of acid, metal complexation and alpha vs. gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mincher, B.J.; Groenewold, G.S. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415 (United States); Mezyk, S.P. [California State University at Long Beach, Long Beach, CA 90840 (United States)

    2016-07-01

    The organophosphorus amide octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl phosphine oxide (CMPO) is proposed for use in fuel cycle separations as a group actinide/lanthanide extractant. Alternative compounds such as the mono-amides and diglycol amides (DGAs) proposed for actinide and/or actinide/lanthanide extraction also contain the amidic functional group, but do not contain the CMPO aromatic or phosphoryl groups. Their radiation stability is in the order mono-amides > CMPO > DGA for irradiation under similar conditions. Although they produce similar radiolysis products, the kinetics of degradation for CMPO are completely different than for the other amides. CMPO degradation occurs in a zero-order fashion, and the -G-value for the change in [CMPO] is much lower when in the presence of acid. The DGAs and mono-amides degrade with pseudo-first-order kinetics and are not protected by acidity. Possible mechanistic reasons for the differences between CMPO and the other amides are discussed, as are the effects of the diluent and metal complexation on CMPO free radical reaction rates. Finally, it is also shown that α-irradiation has much less adverse effects on CMPO degradation than β/γ irradiation, both with respect to -G-values, and radiolysis product generation. (authors)

  8. The effect of combining recombinant human tumor necrosis factor-alpha with local radiation on tumor control probability of a human glioblastoma multiforme xenograft in nude mice

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Peigen; Allam, Ayman; Perez, Luis A; Taghian, Alphonse; Freeman, Jill; Suit, Herman D

    1995-04-30

    Purpose: To evaluate the antitumor activity of recombinant human tumor necrosis factor-alpha (rHuTNF-{alpha}) on a human glioblastoma multiforme (U87) xenograft in nude mice, and to study the effect of combining rHuTNF-{alpha} with local radiation on the tumor control probability of this tumor model. Methods and Materials: U87 xenograft was transplanted SC into the right hindleg of NCr/Sed nude mice (7-8 weeks old, male). When tumors reached a volume of about 110 mm{sup 3}, mice were randomly assigned to treatment: rHuTNF-{alpha} alone compared with normal saline control; or local radiation plus rHuTNF-{alpha} vs. local radiation plus normal saline. Parameters of growth delay, volume doubling time, percentage of necrosis, and cell loss factor were used to assess the antitumor effects of rHuTNF-{alpha} on this tumor. The TCD{sub 50} (tumor control dose 50%) was used as an endpoint to determine the effect of combining rHuTNF-{alpha} with local radiation. Results: Tumor growth in mice treated with a dose of 150 {mu}g/kg body weight rHuTNF-{alpha}, IP injection daily for 7 consecutive days, was delayed about 8 days compared to that in controls. Tumors in the treatment group had a significantly longer volume doubling time, and were smaller in volume and more necrotic than matched tumors in control group. rHuTNF-{alpha} also induced a 2.3 times increase of cell loss factor. The administration of the above-mentioned dose of rHuTNF-{alpha} starting 24 h after single doses of localized irradiation under hypoxic condition, resulted in a significant reduction in TCD{sub 50} from the control value of 60.9 Gy to 50.5 Gy (p < 0.01). Conclusion: rHuTNF-{alpha} exhibits an antitumor effect against U87 xenograft in nude mice, as evidenced by an increased delay in tumor growth as well as cell loss factor. Also, there was an augmentation of tumor curability when given in combination with radiotherapy, resulting in a significantly lower TCD{sub 50} value in the treatment vs. the

  9. Effect of polarized radiative transfer on the Hanle magnetic field determination in prominences: Analysis of hydrogen H alpha line observations at Pic-du-Midi

    Science.gov (United States)

    Bommier, V.; Deglinnocenti, E. L.; Leroy, J. L.; Sahal-Brechot, S.

    1985-01-01

    The linear polarization of the Hydrogen H alpha line of prominences has been computed, taking into account the effect of a magnetic field (Hanle effect), of the radiative transfer in the prominence, and of the depolarization due to collisions with the surrounding electrons and protons. The corresponding formalisms are developed in a forthcoming series of papers. In this paper, the main features of the computation method are summarized. The results of computation have been used for interpretation in terms of magnetic field vector measurements from H alpha polarimetric observations in prominences performed at Pic-du-Midi coronagraph-polarimeter. Simultaneous observations in one optically thin line (He I D(3)) and one optically thick line (H alpha) give an opportunity for solving the ambiguity on the field vector determination.

  10. RAMs: the problem of transient errors due to alpha radiation

    International Nuclear Information System (INIS)

    Goujon, Pierre.

    1980-01-01

    Errors that remained unexplained for a long time have occurred with dynamic random access memories. It has been known since 1978 that they are due to stray alpha radiation. A good understanding of this phenomenon enables its effects to be neutralized and the reliability of the products to be guarantied [fr

  11. Effects of alpha particles on zebrafish embryos

    International Nuclear Information System (INIS)

    Yum, E.H.W.; Choi, V.W.Y.; Yu, K.N.; Li, V.W.T.; Cheng, S.H.

    2008-01-01

    Full text: Ionizing radiation such as X-ray and alpha particles can damage cellular macromolecules, which can lead to DNA single- and double-strand breaks. In the present work, we studied the effects of alpha particles on dechorionated zebrafish embryos. Thin polyallyldiglycol carbonate (PADC) films with a thickness of 16 μm were prepared from commercially available PADC films (with thickness of 100 μm) by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 1.25 hours post fertilization (hpf) with various absorbed dose. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was performed on the embryos at different time stages after irradiation. Marked apoptosis was detected only in embryos at earlier time stages. The results showed that DNA double-strand break during zebrafish embryogenesis can be induced by alpha-particle irradiation, which suggests that zebrafish is a potential model for assessing the effects of alpha-particle radiation

  12. The alpha effect

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Much of the recent interest in RAM system reliability stems from concern over alpha particle soft error rates reported for the initial 64 k RAMs. With increasing memory density likely in the next few years the problem of soft errors is rearing its head again. A few years ago ITT carried out experiments on 16k RAMs and found no significant problems. However, recent tests have shown a raise in the number of soft errors with 64k RAMs, and the launch of 256k and 512k memories is likely to make the problem acute

  13. Spatial distribution patterns of energy deposition and cellular radiation effects in lung tissue following simulated exposure to alpha particles

    International Nuclear Information System (INIS)

    Hofmann, W.; Crawford-Brown, D.J.

    1990-01-01

    Randomly oriented sections of rat tissue have been digitised to provide the contours of tissue-air interfaces and the locations of individual cell nuclei in the alveolated region of the lung. Sources of alpha particles with varying irradiation geometries and densities are simulated to compute the resulting random pattern of cellular irradiation, i.e. spatial coordinates, frequency, track length, and energy of traversals by the emitted alpha particles. Probabilities per unit track lengths, derived from experimental data on in vitro cellular inactivation and transformation, are then applied to the results of the alpha exposure simulations to yield an estimate of the number of both dead and viable transformed cells and their spatial distributions. If lung cancer risk is linearly related to the number of transformed cells, the carcinogenic risk for hot particles is always smaller than that for a uniform nuclide distribution of the same activity. (author)

  14. Alpha radiation detection using silicon memory chips - preliminary studies

    International Nuclear Information System (INIS)

    Pace, R.; Paix, D.; Haskard, M.

    1993-01-01

    Alpha radiation dosage is an important occupational health factor in the mining of uranium and mineral sands. Alpha radiation induced errors in the data of silicon based memory chips provide the foundation for a new type of sensor, with the potential for affordable and prompt measurement of personal alpha doses. With particular reference to Dynamic Random Access Memories (DRAM) this paper introduces the operating principle of a memory based radiation sensor, which is the error mechanism in silicon integrated circuits. 14 refs., 3 figs

  15. The effect of combining recombinant human tumor necrosis factor-alpha with local radiation on tumor control probability of a human glioblastoma multiforme xenograft in nude mice

    International Nuclear Information System (INIS)

    Huang, Peigen; Allam, Ayman; Perez, Luis A.; Taghian, Alphonse; Freeman, Jill; Suit, Herman D.

    1995-01-01

    Purpose: To evaluate the antitumor activity of recombinant human tumor necrosis factor-alpha (rHuTNF-α) on a human glioblastoma multiforme (U87) xenograft in nude mice, and to study the effect of combining rHuTNF-α with local radiation on the tumor control probability of this tumor model. Methods and Materials: U87 xenograft was transplanted SC into the right hindleg of NCr/Sed nude mice (7-8 weeks old, male). When tumors reached a volume of about 110 mm 3 , mice were randomly assigned to treatment: rHuTNF-α alone compared with normal saline control; or local radiation plus rHuTNF-α vs. local radiation plus normal saline. Parameters of growth delay, volume doubling time, percentage of necrosis, and cell loss factor were used to assess the antitumor effects of rHuTNF-α on this tumor. The TCD 50 (tumor control dose 50%) was used as an endpoint to determine the effect of combining rHuTNF-α with local radiation. Results: Tumor growth in mice treated with a dose of 150 μg/kg body weight rHuTNF-α, IP injection daily for 7 consecutive days, was delayed about 8 days compared to that in controls. Tumors in the treatment group had a significantly longer volume doubling time, and were smaller in volume and more necrotic than matched tumors in control group. rHuTNF-α also induced a 2.3 times increase of cell loss factor. The administration of the above-mentioned dose of rHuTNF-α starting 24 h after single doses of localized irradiation under hypoxic condition, resulted in a significant reduction in TCD 50 from the control value of 60.9 Gy to 50.5 Gy (p 50 value in the treatment vs. the control groups

  16. Tumor necrosis factor alpha polymorphism correlates with deleterious effects of ultraviolet B light on cutaneous immunity

    NARCIS (Netherlands)

    Vincek, V.; Kurimoto, I.; Medema, J. P.; Prieto, E.; Streilein, J. W.

    1993-01-01

    Intradermally injected tumor necrosis factor alpha (TNF-alpha) mimics the effects of UV B light (UVB) radiation and neutralizing anti-TNF-alpha antibodies abolish the deleterious effects of UVB on induction of contact hypersensitivity suggesting that TNF-alpha is the major mediator of UVB effects on

  17. Proposal of a weight factor for alpha radiation aiming biota radioprotection

    International Nuclear Information System (INIS)

    Pereira, Wagner de S.; Py Junior, Delcy de A.; Kelecom, Alphonse; Goncalves, Simone

    2009-01-01

    Several proposals based on the environmental radioprotection of calculating the absorbed dose in biota have been suggested. The absorbed dose expresses the deposition of energy per mass unit. The differences in biological effects of the absorbed dose can be quantified by applying a correction factor to the absorbed dose. The correction factor for radiation is easier to establish, because radiations exist in smaller number (alpha, beta, neutrons and photons) and can be set for groups of organisms. This work aims to propose a correction factor for radiation, in order to adequate the concept of absorbed dose currently used to the concept of equivalent dose. A survey of the literature on correction factors proposed for alpha radiation was carried out and, when possible, the biological endpoint was identified, as well as the radionuclide and the biological target. A variation of the weight factor for alpha radiation from 1 to 377 was observed and a number of biological endpoints, biological target and alpha emitter radionuclide were identified. Finally we propose a weight value for alpha radiation of 40, and we propose also the name of correction factor for radiation alpha as being ecological radiation weighting factor (WRE) the name 'equivalent dose for flora and fauna' (HTFF) to name of the new dose. (author)

  18. Radiation-induced biologic bystander effect elicited in vitro by targeted radiopharmaceuticals labeled with alpha-, beta-, and auger electron-emitting radionuclides.

    Science.gov (United States)

    Boyd, Marie; Ross, Susan C; Dorrens, Jennifer; Fullerton, Natasha E; Tan, Ker Wei; Zalutsky, Michael R; Mairs, Robert J

    2006-06-01

    Recent studies have shown that indirect effects of ionizing radiation may contribute significantly to the effectiveness of radiotherapy by sterilizing malignant cells that are not directly hit by the radiation. However, there have been few investigations of the importance of indirect effects in targeted radionuclide treatment. Our purpose was to compare the induction of bystander effects by external beam gamma-radiation with those resultant from exposure to 3 radiohaloanalogs of metaiodobenzylguanidine (MIBG): (131)I-MIBG (low-linear-energy-transfer [LET] beta-emitter), (123)I-MIBG (potentially high-LET Auger electron emitter), and meta-(211)At-astatobenzylguanidine ((211)At-MABG) (high-LET alpha-emitter). Two human tumor cell lines-UVW (glioma) and EJ138 (transitional cell carcinoma of bladder)-were transfected with the noradrenaline transporter (NAT) gene to enable active uptake of MIBG. Medium from cells that accumulated the radiopharmaceuticals or were treated with external beam radiation was transferred to cells that had not been exposed to radioactivity, and clonogenic survival was determined in donor and recipient cultures. Over the dose range 0-9 Gy of external beam radiation of donor cells, 2 Gy caused 30%-40% clonogenic cell kill in recipient cultures. This potency was maintained but not increased by higher dosage. In contrast, no corresponding saturation of bystander cell kill was observed after treatment with a range of activity concentrations of (131)I-MIBG, which resulted in up to 97% death of donor cells. Cellular uptake of (123)I-MIBG and (211)At-MABG induced increasing recipient cell kill up to levels that resulted in direct kill of 35%-70% of clonogens. Thereafter, the administration of higher activity concentrations of these high-LET emitters was inversely related to the kill of recipient cells. Over the range of activity concentrations examined, neither direct nor indirect kill was observed in cultures of cells not expressing the NAT and, thus

  19. Positron annihilation method for {alpha} self radiation effect studies in doped actinide UO{sub 2} samples

    Energy Technology Data Exchange (ETDEWEB)

    Roudil, D.; Vella, F.; Bonnal, M.; Broudic, V. [CEA centre de Marcoule. BP 17171 30207 Bagnols sur ceze cedex (France); Barthe, M.F.; Gentils, A.; Moineau, V. [CNRS- CEMHTI 3A rue de la Ferollerie 45071 Orleans Cedex (France); Jolly, L. [CEA centre de Valduc 21120 Is-Sur Tille (France)

    2008-07-01

    Towards disposal problematic, fine understanding of the {alpha} aging of UO{sub 2} and (U, Pu)O{sub 2} remains a fundamental challenge for the prediction of the potential increase of the radionuclide source terms with presence of water. The intrinsic evolution of the matrix is closely related to the behavior of radiogenic helium produced by actinide decay. Interactions between helium atoms and vacancy defects are involved in these mechanisms. Positron Annihilation Spectroscopy is also an appropriated method owing to its sensitivity to the vacancy type defects in solid materials. It is a non destructive technique with a remote acquiring data possibility. Because positron implanted in the material is sensitive to the electronic density, the positron lifetime method allows the characterization of the vacancy defects, namely size and concentration. Such equipment has been implemented in the L30 laboratory of the DHA facility in Atalante and will be applied on doped actinides samples, simulating {alpha} aging. This article presents, the analytical protocols and validation results on depleted UO{sub 2} samples and highlights the perspectives on (U, Pu)O{sub 2} for the investigation of different stages of self irradiation matrices and helium behavior. (authors)

  20. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles

    International Nuclear Information System (INIS)

    1992-01-01

    The objective of our research work is to provide -- with the aid of biophysical models of radiation action -- information on human risks following exposure to radon alpha particles. The approach proposed consists of (1) developing appropriate models (parametric and non-parametric) for alpha radiation induction of relevant end points (survival, cellular transformation), (2) providing an accurate physical characterization of the particle tracks in terms of nanodosimetric distributions, (3) supporting the models by detailed, molecular studies of the direct and indirect effects of alpha particles on DNA. Activities in the second year of this project are described

  1. Evaluation of pGL1-TNF-alpha therapy in combination with radiation

    Science.gov (United States)

    Li, J.; Andres, M. L.; Fodor, I.; Nelson, G. A.; Gridley, D. S.

    1998-01-01

    Long-term control of high-grade brain tumors is rarely achieved with current therapeutic regimens. In this study a new plasmid-based human tumor necrosis factor-alpha (TNF-alpha) expression vector was synthesized (pGL1-TNF-alpha) and evaluated together with radiation in the aggressive, rapidly growing C6 rat glioma model. pGL1-TNF-alpha was successfully transfected into C6 cells in vitro using a cationic polyamine method. Expression was detected up to 7 days and averaged 0.4 ng of TNF-alpha in the culture medium from 1x10(5) cells. The expressed protein was biologically functional, as evidenced by growth inhibition of L929, a TNF-alpha-susceptible cell line. Using fluorescence-labeled monoclonal antibodies and laser scanning cytometry, we confirmed that both the P55 and P75 receptors for TNF-alpha were present on the C6 cell membrane. However, the receptors were present at low density and P55 was expressed more than the P75 receptor. These findings were in contrast to results obtained with TNF-alpha-susceptible L929 cells. Tests in athymic mice showed that pGL1-TNF-alpha administered intratumorally 16-18 h before radiation (each modality given three times) significantly inhibited C6 tumor progression (Palpha alone did not slow tumor growth and radiation alone had little effect on tumor growth. These results indicate that pGL1-TNF-alpha has potential to augment the antitumor effects of radiation against a tumor type that is virtually incurable.

  2. The semiconductor doping with radiation defects via proton and alpha-particle irradiation. Review

    CERN Document Server

    Kozlov, V A

    2001-01-01

    Paper presents an analytical review devoted to semiconductor doping with radiation defects resulted from irradiation by light ions, in particular, by protons and alpha-particles. One studies formation of radiation defects in silicon, gallium arsenide and indium phosphide under light ion irradiation. One analyzes effect of proton and alpha-particle irradiation on electric conductivity of the above-listed semiconducting materials. Semiconductor doping with radiation defects under light ion irradiation enables to control their electrophysical properties and to design high-speed opto-, micro- and nanoelectronic devices on their basis

  3. The effects and control of radiation

    International Nuclear Information System (INIS)

    Saunders, P.A.H.

    1982-12-01

    The subject is discussed under the headings: introduction; ionising radiation (alpha and beta particles, gamma- and X-radiation, neutrons, half-life, sources of radiation); biological effects; risk estimates (somatic) (early effects, delayed effects); risk estimates (hereditary); control of radiation; risk estimates (accidents). (U.K.)

  4. Apparatus for detecting alpha radiation in difficult access areas

    International Nuclear Information System (INIS)

    Steadman, P.; MacArthur, D.W.

    1997-01-01

    An electrostatic alpha radiation detector for measuring alpha radiation emitted from inside an enclosure comprising an electrically conductive expandable electrode for insertion into the enclosure is disclosed. After insertion, the electrically conductive expandable electrode is insulated from the enclosure and defines a decay cavity between the electrically conductive expandable electrode and the enclosure so that air ions generated in the decay cavity are electrostatically captured by the electrically conductive expandable electrode and the enclosure when an electric potential is applied between the electrically conductive expandable electrode and the enclosure. Indicator means are attached to the electrically conductive expandable electrode for indicating an electrical current produced by generation of the air ions generated in the decay cavity by collisions between air molecules and the alpha particles emitted from the enclosure. A voltage source is connected between the indicator means and the electrically conductive enclosure for creating an electric field between the electrically conductive expandable electrode and the enclosure. 4 figs

  5. Alpha radiation gauge for the measurement of gas density

    International Nuclear Information System (INIS)

    Lech, M.

    1977-01-01

    Alpha gauge for the measurement of gas density with thick alfa source, has been developed. The gauge is based on radiation transmission through a space filled with gas and total-count principle. Air density can be measured in the range 1,2 - 1,27 kg m -3 with a maximum standard deviation of 2 x 10 -3 kg m -3 . (author)

  6. Health effects of ionizing radiation

    International Nuclear Information System (INIS)

    Pathak, B.

    1989-12-01

    Ionizing radiation is energy that travels through space as electromagnetic waves or a stream of fast moving particles. In the workplace, the sources of ionizing radiation are radioactive substances, nuclear power plants, x-ray machines and nuclear devices used in medicine, research and industry. Commonly encountered types of radiation are alpha particles, beta particles and gamma rays. Alpha particles have very little penetrating power and pose a risk only when the radioactive substance is deposited inside the body. Beta particles are more penetrating than alpha particles and can penetrate the outer body tissues causing damage to the skin and the eyes. Gamma rays are highly penetrating and can cause radiation damage to the whole body. The probability of radiation-induced disease depends on the accumulated amount of radiation dose. The main health effects of ionizing radiation are cancers in exposed persons and genetic disorders in the children, grandchildren and subsequent generations of the exposed parents. The fetus is highly sensitive to radiation-induced abnormalities. At high doses, radiation can cause cataracts in the eyes. There is no firm evidence that ionizing radiation causes premature aging. Radiation-induced sterility is highly unlikely for occupational doses. The data on the combined effect of ionizing radiation and other cancer-causing physical and chemical agents are inconclusive

  7. Dislocations and radiation damage in {alpha}-uranium; Dislocations et effets des radiations dans l'uranium {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Leteurtre, J. [Commissariat a l' Energie Atomique, 92 - Fontenay-Aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    Dislocations in {alpha}-uranium were studied by electron microscopy. Electropolishing of thin foils was performed at low temperature (-110 deg. C) to prevent oxidation. Burgers vectors of twins dislocations are defined. Interactions between slip and twinning are studied from both experimental and theoretical point of view. Samples irradiated at several burn-up were examined. In order to explain our micrographic results, and also all information gathered in literature about radiation damage in {alpha}-uranium, a coherent model is propound for the fission particles effects. We analyse the influences of parameters: temperature, dislocation density, impurity content. The number of point defects created by one initial fission is determined for pure and annealed metal. The importance of the self-anneal which occurs immediately in each displacement spike, and the anneal due to a new fission on the damage resulting from a previous fission, are estimated. The focussing distance in [100] direction is found to be about 1000 Angstrom, at 4 deg. K. (author) [French] Ce travail est une etude par microscopie electronique des dislocations induites dans l'uranium {alpha}, soit par deformation plastique, soit par irradiation. Une methode de preparation des lames minces a basse temperature (-110 deg. C) a ete mise au point. Les vecteurs de Burgers des diverses dislocations de macles de ce metal ont ete definis. Les interactions glissements- maclages sont etudiees experimentalement et theoriquement. Des echantillons irradies a divers taux de combustion ont ete examines. Pour expliquer nos resultats micrographiques, et aussi l'ensemble des informations recueillies dans la litterature concernant l'endommagement par irradiation de l'uranium-{alpha}, nous proposons un modele coherent de l'effet des fragments de fission dans ce metal. L'influence des parametres: temperature, densite de dislocations, impuretes est analysee. Le nombre de defauts ponctuels crees

  8. Dislocations and radiation damage in {alpha}-uranium; Dislocations et effets des radiations dans l'uranium {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Leteurtre, J [Commissariat a l' Energie Atomique, 92 - Fontenay-Aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    Dislocations in {alpha}-uranium were studied by electron microscopy. Electropolishing of thin foils was performed at low temperature (-110 deg. C) to prevent oxidation. Burgers vectors of twins dislocations are defined. Interactions between slip and twinning are studied from both experimental and theoretical point of view. Samples irradiated at several burn-up were examined. In order to explain our micrographic results, and also all information gathered in literature about radiation damage in {alpha}-uranium, a coherent model is propound for the fission particles effects. We analyse the influences of parameters: temperature, dislocation density, impurity content. The number of point defects created by one initial fission is determined for pure and annealed metal. The importance of the self-anneal which occurs immediately in each displacement spike, and the anneal due to a new fission on the damage resulting from a previous fission, are estimated. The focussing distance in [100] direction is found to be about 1000 Angstrom, at 4 deg. K. (author) [French] Ce travail est une etude par microscopie electronique des dislocations induites dans l'uranium {alpha}, soit par deformation plastique, soit par irradiation. Une methode de preparation des lames minces a basse temperature (-110 deg. C) a ete mise au point. Les vecteurs de Burgers des diverses dislocations de macles de ce metal ont ete definis. Les interactions glissements- maclages sont etudiees experimentalement et theoriquement. Des echantillons irradies a divers taux de combustion ont ete examines. Pour expliquer nos resultats micrographiques, et aussi l'ensemble des informations recueillies dans la litterature concernant l'endommagement par irradiation de l'uranium-{alpha}, nous proposons un modele coherent de l'effet des fragments de fission dans ce metal. L'influence des parametres: temperature, densite de dislocations, impuretes est analysee. Le nombre de defauts ponctuels crees par une fission dans du metal

  9. Radiation effects

    International Nuclear Information System (INIS)

    Collings, E.W.

    1986-01-01

    An important cause of deterioration in superconducting magnets intended for high-energy physics and fusion-reactor applications is radiation damage. The present chapter deals chiefly with the effects of electron, proton, gamma and neutron irradiation on the properties of stabilized Ti-Nb-base composite superconductors. The authors examine the particle-accelerator environment, electron irradiation of Ti-Nb superconductor, proton irradiation of Ti-Nb superconductor and its stabilizer, and deuteron irradiation of Ti-Nb superconductor. A section discussing the fusion reactor environment in general is presented, and the two principal classes of fusion reactor based on the magnetic-confinement concept, namely the tokamak and the mirrormachine are examined. Also discussed is neutron irradiation of Cu/TiNb composite superconductors and critical current density of neutronirradiated Ti-Nb. Finally, radiation damage to stabilizer and insulating materials is described

  10. Effect of alpha-calciferol on bone mineral density, bone histomorphometry and bone biomechanics in rats by radiative injury to kidney

    International Nuclear Information System (INIS)

    Zhu Feipeng; Wang Hongfu; Gao Linfeng; Jin Weifang

    2003-01-01

    The work is to study the effects of alpha-calciferol on bone mineral density, histomorphometry and biomechanics in rats with osteoporosis induced by irradiation of the rat kidney. 32 male SD rats of six months in age were randomly divided into 4 groups (8 rats per group), i.e. the model group, the sham group, the bone one group and the fosamax group. Osteoporosis was developed in the rats by irradiating the kidney. Then the rats were administrated orally as follows in a 90 days, 0.1 g·kg -1 BW.d of alpha-calciferol for the bone one group, 10 mg·kg -1 BW.d of alendronate sodium in 1 mL CMC for the fosamax group, and 1 mL CMC for both the model group and sham group. BMD of L1-4, bone histomorphometry and the bone biomechanical properties were measured. Compared with the model group, both the bone one group and the fosamax group were characterized with significantly higher BMD of L1-4 (p<0.01), significantly larger volume and width of bone trabecula, smaller space of bone trabecula (p<0.05, p<0.01), and significantly larger maximal stress of femur and lumbar vertebra (p<0.05, p<0.01). It is concluded that Alpha-calciferol can improve BMD, bone histomorphometry and bone biomechanical properties in rat osteoporosis induced by kidney irradiation

  11. Biological Effects of Radiation

    International Nuclear Information System (INIS)

    Jatau, B.D.; Garba, N.N.; Yusuf, A.M.; Yamusa, Y. A.; Musa, Y.

    2013-01-01

    In earlier studies, researchers aimed a single particle at the nucleus of the cell where DNA is located. Eighty percent of the cells shot through the nucleus survived. This contradicts the belief that if radiation slams through the nucleus, the cell will die. But the bad news is that the surviving cells contained mutations. Cells have a great capacity to repair DNA, but they cannot do it perfectly. The damage left behind in these studies from a single particle of alpha radiation doubled the damage that is already there. This proved, beyond a shadow of doubt, those there biological effects occur as a result of exposure to radiation, Radiation is harmful to living tissue because of its ionizing power in matter. This ionization can damage living cells directly, by breaking the chemical bonds of important biological molecules (particularly DNA), or indirectly, by creating chemical radicals from water molecules in the cells, which can then attack the biological molecules chemically. At some extent these molecules are repaired by natural biological processes, however, the effectiveness of this repair depends on the extent of the damage. The interaction of ionizing with the human body, arising either from external sources outside the body or from internal contamination of the body by radioactive materials, leads to the biological effects which may later show up as a clinical symptoms. Basically, this formed the baseline of this research to serve as a yardstick for creating awareness about radiation and its resulting effects.

  12. In vitro effects of infrared A radiation on the synthesis of MMP-1, catalase, superoxide dismutase and GADD45 alpha protein.

    Science.gov (United States)

    Costa, Adilson; Eberlin, Samara; Clerici, Stefano P; Abdalla, Beatrice M Z

    2015-01-01

    Harmful influences in the process of photoaging and skin damage are associated with infrared A (IRA) radiation, such as, disturbance of dermal extracellular matrix by up regulation of matrix metalloproteinase-1 (MMP1). Furthermore, DNA damage, induction of cytotoxicity and oxidative stress by decreasing natural antioxidant ability has been reported after acute exposure to IRA. The present study provides additional evidence that IRA radiation response in human skin fibroblasts produces deleterious effects to the cell, such as accelerating aging and weakening of their antioxidant defense mechanism. Human skin fibroblasts were exposed to a non-cytotoxic dose of IRA radiation and cultured for different periods for further collection of cell-free supernatants and lysates, and quantification of MMP-1, catalase, superoxide dismutase, and GADD45a. Our results corroborate previous published data and strongly indicate a negative impact of IRA radiation on the skin physiological by mechanisms involving reduced endogenous antioxidant enzymatic defense, increased MMP-1 and decreased repair process of DNA by reducing GADD45a protein, in cultured human fibroblasts. From a clinical perspective, IRA radiation acts by mechanisms distinct from those observed in ultraviolet radiation indicating the need for developing and making available cosmetics for skin care with properties beyond protection exerted by traditional sunscreens.

  13. Biological stress responses induced by alpha radiation exposure in Lemna minor

    Energy Technology Data Exchange (ETDEWEB)

    Van Hoeck, A.; Horemans, N.; Van Hees, M.; Nauts, R. [Belgian Nuclear Research Centre SCK-CEN (Belgium); Knapen, D.; Blust, R. [University of Antwerp (Belgium)

    2014-07-01

    To enhance the robustness of radiation protection criteria for biota, additional information on the biological impact of radionuclides on non-human biota is needed. In particular the effects of alpha emitting isotopes have been poorly studied within a radioecological contextual though they exhibit a high linear energy transfer which can cause significant biological damage when taken up by organisms. Therefore, it is not only essential to measure alpha radiation toxicity, but also try to understand the underlying mechanisms of this stressor. The current study aimed to contribute to a better knowledge of the fundamental processes regulating alpha radiation stress response mechanisms in higher plants. {sup 241}Am was primarily selected as it is an almost pure alpha emitter and, as a daughter nuclide of {sup 241}Pu, it will become one of the dominant pollutants in plutonium affected areas. The aquatic macrophyte Lemna minor has proven its value in eco-toxicological research as representative of higher aquatic plants (OECD guideline nr. 221) and will be used to analyze alpha radiation stress in plant systems. An individual growth inhibition test was set up by means of single dose-response curve in order to identify the Effective Dose Rates (EDR-values) for frond size and biomass. As the mean path length is small for alpha particles, the accumulation of the radionuclide inside species represents almost exclusively the dosimetry. Therefore, quantification of {sup 241}Am uptake and {sup 241}Am distribution were evaluated separately for roots and fronds taking the activity concentrations of growth medium into account. Taken together with the respective dose conversion coefficients from the ERICA tool, this allowed to construct an accurate dosimetric model to determine internal and external dose rates. Different standard media were tested on growth rate and biomass to analyse the amount of {sup 241}Am taken up by the plants exposed from 2.5 to 100 kBq/L. From these

  14. Choosing an alpha radiation weighting factor for doses to non-human biota

    International Nuclear Information System (INIS)

    Chambers, Douglas B.; Osborne, Richard V.; Garva, Amy L.

    2006-01-01

    The risk to non-human biota from exposure to ionizing radiation is of current international interest. In calculating radiation doses to humans, it is common to multiply the absorbed dose by a factor to account for the relative biological effectiveness (RBE) of the radiation type. However, there is no international consensus on the appropriate value of such a factor for weighting doses to non-human biota. This paper summarizes our review of the literature on experimentally determined RBEs for internally deposited alpha-emitting radionuclides. The relevancy of each experimental result in selecting a radiation weighting factor for doses from alpha particles in biota was judged on the basis of criteria established a priori. We recommend a nominal alpha radiation weighting factor of 5 for population-relevant deterministic and stochastic endpoints, but to reflect the limitations in the experimental data, uncertainty ranges of 1-10 and 1-20 were selected for population-relevant deterministic and stochastic endpoints, respectively

  15. Radiation induced structural changes in alpha-copper-zinc alloys

    International Nuclear Information System (INIS)

    Schuele, W.; Gieb, M.

    1991-01-01

    During irradiation of alpha-copper-zinc alloys with high energy electrons and protons a decrease of the electrical resistivity due to an increase of the degree of short range order is observed through radiation enhanced diffusion followed by an increase of the electrical resistivity through the formation of radiation induced interstitial clusters. The initial formation rate of interstitial clusters increases about linearly with the displacement rate for electron and proton irradiation. The largest initial formation rate is found between 60 and 130 0 C becoming negligibly small above 158 0 C and decreases drastically below 60 0 C. The dynamic steady state interstitial cluster concentration increases with decreasing irradiation temperature in the investigated temperature range between 158 and 40 0 C. Above 158 0 C the formation rate of interstitial clusters is negligibly small. Thus the transition temperature for radiation induced interstitial cluster formation is 158 0 C, depending mainly on the migration activation energy of vacancies. The radiation induced interstitial clusters are precipitates in those alloys in which the diffusion rate of the undersized component atoms via an interstitialcy diffusion mechanism is larger than that of the other atoms

  16. Determination of alpha constant value for brazilian reality aiming de radiation protection optimization

    International Nuclear Information System (INIS)

    Teixeira, Pedro Barbosa

    2003-01-01

    This work aims to present a methodology for the calculation of the alpha constant taking into account the actual conditions in Brazil. This constant is used for the minimization of the worker doses meaning the optimization of radiation protection. The alpha constant represents a monetary value to establish the health detriment associated to the stochastic effects for unit of collective dose, and is directly related to the value of the human life. Along the years, several methods have been developed to obtain the most appropriate value for the alpha constant. These methods will be objects of analysis of this work. This work presents two methods for determination of the alpha constant: 'human capital' that is based on GDP of the country and 'willingness-to-pay' that is established for the value that the population would be willing to pay for the safety of the nuclear and radioactive facilities. A new methodology for the calculation of the alpha constant has been proposed in this study, that is the combination of two method previously mentioned, and recommends a new value of US$ 16,000.00 per man-sievert. Currently the value established by CNEN is US$ 10,000.00 per men sievert. This work also presents, in full details, the main mathematical tools for the elaboration of the optimization of the radiation protection: cost-benefit analysis, extended cost-benefit analysis and multi attribute utility analysis. An applied example, for an uranium mine radiation protection optimization was used to compare those two values of the alpha constant. (author)

  17. Bystander effects of radiation

    International Nuclear Information System (INIS)

    Umar, Neethu Fathima; Daniel, Nittu

    2013-01-01

    The Radiation-Induced Bystander Effect is the phenomenon in which unirradiated cells show irradiated effects due to the signals received from nearby irradiated cells. Evidence suggests that targeted cytoplasmic irradiation results in mutation in the nucleus of the hit cells. Cells that are not directly hit by an alpha particle, but are in the vicinity of one that is hit, also contribute to the genotoxic response of the cell population. When cells are irradiated, and the medium is transferred to unirradiated cells, these unirradiated cells show bystander responses when assayed for clonogenic survival and oncogenic transformation. The demonstration of a bystander effect in human tissues and, more recently, in whole organisms have clear implication of the potential relevance of the non-targeted response to human health. This effect may also contribute to the final biological consequences of exposure to low doses of radiation. The radiation-induced bystander effect represents a paradigm shift in our understanding of the radiobiological effects of ionizing radiation, in that extranuclear and extracellular events may also contribute to the final biological consequences of exposure to low doses of radiation. Multiple pathways are involved in the bystander phenomenon, and different cell types respond differently to bystander signalling. Using cDNA microarrays, a number of cellular signalling genes, including cyclooxygenase-2 (CQX-2), have been shown to be casually linked to the bystander phenomenon. The observation that inhibition of the phosphorylation of extracellular signal-related kinase (ERK) suppressed the bystander response further confirmed the important role of the mitogen-activated protein kinase (MAPK) signalling cascade in the bystander process. The cells deficient in mitochondrial DNA showed a significantly reduced response to bystander signalling, suggesting a functional role of mitochondria in the signalling process. (author)

  18. Possible inducement of skin basaloma by external alpha radiation

    International Nuclear Information System (INIS)

    Sevcova, M.; Sevc, J.; Thomas, J.

    1975-01-01

    A comparison was made of the latest data on the thickness of the epidermis and the resulting estimate of dose rates to its basal layer with the results of several years of clinical observation in uranium miners exposed over a long term to alpha radiation from a 222 Rn daughter product deposit on the skin. It was found that the average dose equivalent in the basal layer of the epidermis from deposited 222 Rn daughter products was within the region of tens of rem/year even under good hygienic conditions in the uranium mine, and accumulated doses may after several years of exposure reach several thousands rems. In the narrow selection of workers where statistical comparison was possible it appeared that the frequency of observed skin carcinomas, mainly basal carcinomas of the face, neck and hands, is significantly higher in miners working in underground mines as against expected incidence. (B.S.)

  19. A method of alpha-radiating nuclide activity measuring in aerosol filters

    International Nuclear Information System (INIS)

    Ignatov, V.P.; Galkina, V.N.

    1992-01-01

    Scintillation method of determination of alpha-radiating nuclide activity in aerosol filters was suggested. The method involves dissolution of the filter in organic solvent, introduction of luminophore into solution prepared, drying of the preparation and measurement of radionuclide activity. Dependences of alpha-radiation detection efficiency on the content of luminophore, filter material, colourless and coloured substances in preparations analyzed were considered

  20. Response of CVD diamond detectors to alpha radiation

    Energy Technology Data Exchange (ETDEWEB)

    Souw, E.-K. [Brookhaven National Lab., Upton, NY (United States); Meilunas, R.J. [Northrop-Grumman Corporation, Bethpage, NY 11714-3582 (United States)

    1997-11-21

    This article describes some results from an experiment with CVD diamond films used as {alpha} particle detectors. It demonstrates that bulk polarization can be effectively stopped within a reasonable time interval. This will enable detector calibration and quantitative measurement. A possible mechanism for the observed polarization quenching is discussed. It involves two types of carrier traps and a tentative band-gap model derived from the results of photoconductive current measurements. The experiment was set up mainly to investigate {alpha} detection properties of polycrystalline diamond films grown by the technique of microwave plasma enhanced chemical vapor deposition. For comparison, two commercially purchased diamond wafers were also investigated, i.e., one grown by the DC arc jet method, and the other, a type-IIa natural diamond wafer (not preselected). The best response to {alpha} particles was obtained using diamond thin-films grown by the microwave PECVD method, followed by the type-IIa natural diamond, and finally, the CVD diamond grown by the DC arc jet technique. (orig.). 43 refs.

  1. Nanodosimetry and nanodosimetric-based models of radiation action for radon alpha particles. Final performance technical report

    International Nuclear Information System (INIS)

    Zaider, M.

    1997-01-01

    The goal of this project was to develop theoretical/computational tools for evaluating the risks incurred by populations exposed to radon alpha particles. Topics of concern include the following: compound dual radiation action (general aspects); a mathematical formalism describing the yield of radiation induced single-and double-strand DNA breaks, and its dependence on radiation quality; a study of the excited states in cytosine and guanine stacks in the Hartree-Fock and exciton approximations; nanodosimetry of radon alpha particles; application of the HSEF to assessing radiation risks in the practice of radiation protection; carcinogenic risk coefficients at environmental levels of radon exposures: a microdosimetric approach; and hit-size effectiveness approach in radiation protection

  2. Effects of internally deposited alpha emitters

    International Nuclear Information System (INIS)

    Rundo, J.; Schlenker, R.A.; Stebbings, J.H.

    1985-01-01

    This study seeks to identify and quantify the human health effects of occupational exposures to radium, use the health effects data from the radium study to predict responses to other alpha-emitting and/or bone-seeking radionuclides at occupational exposure levels and above, and predict the effects of these radionuclides, specifically environmental radium and its daughters, at nonoccupational exposure levels. 14 refs

  3. Standoff alpha radiation detection for hot cell imaging and crime scene investigation

    Science.gov (United States)

    Kerst, Thomas; Sand, Johan; Ihantola, Sakari; Peräjärvi, Kari; Nicholl, Adrian; Hrnecek, Erich; Toivonen, Harri; Toivonen, Juha

    2018-02-01

    This paper presents the remote detection of alpha contamination in a nuclear facility. Alpha-active material in a shielded nuclear radiation containment chamber has been localized by optical means. Furthermore, sources of radiation danger have been identified in a staged crime scene setting. For this purpose, an electron-multiplying charge-coupled device camera was used to capture photons generated by alpha-induced air scintillation (radioluminescence). The detected radioluminescence was superimposed with a regular photograph to reveal the origin of the light and thereby the alpha radioactive material. The experimental results show that standoff detection of alpha contamination is a viable tool in radiation threat detection. Furthermore, the radioluminescence spectrum in the air is spectrally analyzed. Possibilities of camera-based alpha threat detection under various background lighting conditions are discussed.

  4. Alpha-risk: a European project on the quantification of risks associated with multiple radiation exposures

    International Nuclear Information System (INIS)

    Laurier, D.; Monchaux, G.; Tirmarche, M.; Darby, S.; Cardis, E.; Binks, K.; Hofmann, W.; Muirhead, C.

    2006-01-01

    The Alpha-Risk research project is being conducted within the Sixth European Framework Programme (EC-FP6, 2005 -2008). It aims to improve the quantification of risks associated with multiple exposures, taking into account the contribution of different radionuclides and external exposure using specific organ dose calculations. The Alpha-Risk Consortium involves 18 partners from 9 countries, and is coordinated by the IRSN. Its composition allows a multidisciplinary collaboration between researchers in epidemiology, dosimetry, statistics, modelling and risk assessment. Alpha-Risk brings together major epidemiological studies in Europe, which are able to evaluate long-term health effects of internal exposure from radionuclides. It includes large size cohort and case-control studies, with accurate registration of individual annual exposures: uranium miner studies, studies on lung cancer and indoor radon exposure, and studies of lung cancer and leukaemia among nuclear workers exposed to transuranic nuclides (mainly uranium and plutonium), for whom organ doses will be reconstructed individually. The contribution of experts in dosimetry will allow the calculation of organ doses in presence of multiple exposures (radon decay products, uranium dust and external gamma exposure). Expression of the risk per unit organ dose will make it possible to compare results with those from other populations exposed to external radiation. The multidisciplinary approach of Alpha-Risk promotes the development of coherent and improved methodological approaches regarding risk modelling. A specific work - package is dedicated to the integration of results and their use for risk assessment, especially for radon. Alpha-Risk will contribute to a better understanding of long-term health risks following chronic low doses from internal exposures. The project also has the great potential to help resolve major public health concerns about the effects of low and/or protracted exposures, especially

  5. Alpha particle effects on MHD ballooning

    International Nuclear Information System (INIS)

    1991-01-01

    During the period, as the first step towards the goal of detail understanding of the effects of alpha particle on MHD Ballooning Modes, a new numerical approach to investigate the stability of low-frequency fluctuations in high temperature tokamaks was developed by solving the gyrokinetic equations for the ion and electron directly as an initial value problem. The advantage of this approach is the inclusion of many important kinetic features of the problem without approximations and computationally more economical than particle-pushing simulation. The ion-temperature-gradient-mode was investigated to benchmark this new simulation technique. Previous results in literature were recovered. Both the adiabatic electron model and the full drift-kinetic electron model are studied. Numerical result shows that the full drift-kinetic electron model is more unstable. The development of subcycling technique to handle the fast electron bounce time is particularly significant to apply this new approach to the alpha particle problem since alpha particle bounce frequency is also significantly higher than the mode frequency. This new numerical technique will be the basis of future study of the microstability in high temperature tokamaks with alpha particles (or any energetic species). 15 refs., 13 figs

  6. Combined effect of tumor necrosis factor-alpha and ionizing radiation on the induction of apoptosis in 5637 bladder carcinoma cells

    International Nuclear Information System (INIS)

    Baierlein, S.A.; Distel, L.; Sieber, R.; Weiss, C.; Roedel, C.; Sauer, R.; Roedel, F.

    2006-01-01

    Background and Purpose: Apoptosis can be induced by distinct but overlapping pathways. Ionizing radiation induces apoptosis by an ''intrinsic'', mitochondria-dependent pathway. Ligation of tumor necrosis factor-(TNF-)α, FAS (CD95) or TRAIL receptors are typical representatives of an extrinsic, death-receptor-mediated pathway. In this study the effect of irradiation, treatment with the cytokine TNF-α, or a combination of both on the induction of apoptosis and clonogenic survival of bladder carcinoma cells was investigated. Material and Methods: 5637 bladder carcinoma cells were treated with different concentrations of recombinant TNF-α (0-10 ng/ml), irradiated with single doses ranging from 0.5 to 10 Gy, or a combination of both modalities. Apoptotic cells were quantified by the TUNEL assay up to 96 h following treatment, clonogenic cell survival by a clonogenic assay. Synergistic effects of both modalities were evaluated using isobolographic analysis. Results: Irradiation of 5637 carcinoma cells resulted in a discontinuous dose dependence of the apoptotic fraction with a pronounced increase in the range of 0-2 Gy and a slighter increase at 2-10 Gy. The percentage of apoptotic carcinoma cells also increased continuously after treatment with lower concentrations of TNF-α reaching a plateau at concentrations of 5.0-10.0 ng/ml. Isobolographic analysis revealed a supraadditive interrelationship between irradiation and TNF-α in the range between 0.005 and 0.5 ng/ml, and an additive effect for TNF-α concentrations > 0.5 ng/ml. The additive effects were confirmed in clonogenic survival assays with reduced survival fractions following combined TNF-α administration and irradiation. Conclusion: The combination of two apoptosis-inducing modalities resulted in a synergistic effect on the induction of apoptosis in 5637 bladder carcinoma cells. Although a radiosensitizing effect still has to be proven in animal models, combined-modality treatment may increase the

  7. Radiation effects at ISABELLE

    International Nuclear Information System (INIS)

    Sanger, P.A.; Danby, G.T.

    1975-01-01

    Shielding, radiation damage, and radiation heating at the planned ISABELLE storage rings were considered. Radiation shielding studies were reviewed and were found to be adequate for present day dosage limits. Radiation damage could be encountered in some extreme cases, but is not expected to limit the performance of the superconducting magnets. Experiments to study the effect of radiation heating on actual magnets are recommended

  8. Radiation effects and radiation risks

    International Nuclear Information System (INIS)

    Lengfelder, E.; Forst, D.; Feist, H.; Pratzel, H.

    1988-01-01

    The book presents the facts and the principles of assessment and evaluation of biological radiation effects in general and also with particular reference to the reactor accident of Chernobyl, reviewing the consequences and the environmental situation on the basis of current national and international literature, including research work by the authors. The material compiled in this book is intended especially for physicians, but will also prove useful for persons working in the public health services, in administration, or other services taking care of people. The authors tried to find an easily comprehensible way of presenting and explaining the very complex processes and mechanisms of biological radiation effects and carcinogenesis, displaying the physical primary processes and the mechanisms of the molecular radiation effects up to the effects of low-level radiation, and present results of comparative epidemiologic studies. This section has been given considerable space, in proportion to its significance. It also contains literature references for further reading, offering more insight and knowledge of aspects of special subject fields. The authors also present less known results and data and discuss them against the background of well-known research results and approaches. Apart from the purpose of presenting comprehensive information, the authors intend to give an impact for further thinking about the problems, and helpful tools for independent decisions and action on the basis of improved insight and assessment, and in this context particularly point to the problems induced by the Chernobyl reactor accident. (orig./MG) With 8 maps in appendix [de

  9. Combined adjuvant radiation and interferon-alpha 2B therapy in high-risk melanoma patients: the potential for increased radiation toxicity

    International Nuclear Information System (INIS)

    Hazard, Lisa J.; Sause, William T.; Noyes, R. Dirk

    2002-01-01

    Purpose: Surgically resected melanoma patients with high-risk features commonly receive adjuvant therapy with interferon-alpha 2b combined with radiation therapy; the purpose of our study was to evaluate the potential enhancement of radiation toxicity by interferon. Methods and Materials: Patients at LDS Hospital and the University of Utah Medical Center in Salt Lake City treated with interferon during radiotherapy or within 1 month of its completion were retrospectively identified, and their charts were reviewed. If possible, the patients were asked to return to the LDS Hospital radiation therapy department for follow-up. Results: Five of 10 patients receiving interferon-alpha 2b therapy during radiation therapy or within 1 month of its completion experienced severe subacute/late complications of therapy. Severe subacute/late complications included two patients with peripheral neuropathy, one patient with radiation necrosis in the brain, and two patients with radiation necrosis in the s.c. tissue. One patient with peripheral neuropathy and one patient with radiation necrosis also developed lymphedema. Conclusions: In vitro studies have identified a radiosensitizing effect by interferon-alpha on certain cell lines, which suggests the possibility that patients treated with interferon and radiation therapy may experience more severe radiation toxicities. We have observed severe subacute/late complications in five of 10 patients treated with interferon-alpha 2b during radiation therapy or within 1 month of its completion. Although an observational study of 10 patients lacks the statistic power to reach conclusions regarding the safety and complication rates of combined interferon and radiation therapy, it is sufficient to raise concerns and suggest the need for prospective studies

  10. Radiation effects in silicate glasses

    International Nuclear Information System (INIS)

    Bibler, N.E.; Howitt, D.G.

    1988-01-01

    The study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as high level nuclear waste immobilization and fiber optics. Radiation changes the properties of these glasses by altering their electronic and atomic configurations. These alterations or defects may cause dilatations or microscopic phase changes along with absorption centers that limit the optical application of the glasses. Atomic displacements induced in the already disordered structure of the glasses may affect their use where heavy irradiating particles such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may result. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions. In the paper, the authors review the literature concerning radiation effects on density, durability, stored energy, microstructure and optical properties of silicate glasses. Both simple glasses and complex glasses used for immobilization of nuclear waste are considered

  11. Tumor necrosis factor alpha selectively sensitizes human immunodeficiency virus-infected cells to heat and radiation

    International Nuclear Information System (INIS)

    Wong, G.H.; McHugh, T.; Weber, R.; Goeddel, D.V.

    1991-01-01

    We report here that infection of the human T-cell line HUT-78 with human immunodeficiency virus (HIV) increases its sensitivity to heat and radiation toxicity. A possible explanation for this result may be the reduced expression of manganous superoxide dismutase (MnSOD) in HIV-infected cells compared to uninfected cells. Tumor necrosis factor alpha (TNF-alpha) further sensitizes HIV-infected cells but not uninfected cells to heat and radiation. This is consistent with the ability of TNF-alpha to induce the expression of MnSOD in uninfected but not in HIV-infected cells. HIV-infected HUT-78 cell lines engineered to overexpress MnSOD are more resistant to heat and radiation than HIV-infected cells that do not overexpress MnSOD. However, treatment with TNF-alpha still sensitizes these cells to heat and radiation

  12. Alpha particle response for a prototype radiation survey meter based on poly(ethylene terephthalate) with un-doping fluorescent guest molecules

    International Nuclear Information System (INIS)

    Nguyen, Philip; Nakamura, Hidehito; Sato, Nobuhiro; Takahashi, Tomoyuki; Maki, Daisuke; Kanayama, Masaya; Takahashi, Sentaro; Kitamura, Hisashi; Shirakawa, Yoshiyuki

    2016-01-01

    There is no radiation survey meter that can discriminate among alpha particles, beta particles, and gamma-rays with one material. Previously, undoped poly(ethylene terephthalate) (PET) has been shown to be an effective material for beta particle and gamma-ray detection. Here, we demonstrate a prototype survey meter for alpha particles based on undoped PET. A 140 × 72 × 1-mm PET substrate was fabricated with mirrored surfaces. It was incorporated in a unique detection section of the survey meter that directly detects alpha particles. The prototype exhibited an unambiguous response to alpha particles from a 241 Am radioactive source. These results demonstrate that undoped PET can perform well in survey meters for alpha particle detection. Overall, the PET-based survey meter has the potential to detect multiple types of radiation, and will spawn an unprecedented type of radiation survey meter based on undoped aromatic ring polymers. (author)

  13. Determination of alpha effectiveness in ESR dating using nuclear accelerator techniques: methods and energy dependence

    International Nuclear Information System (INIS)

    Lyons, R.G.

    1988-01-01

    An important parameter in calculating the environmental dose rate for electron spin resonance (ESR) age estimates is the relative effectiveness of alpha and gamma radiation. A small research accelerator is used as a source of alpha particles of various pre-selected energies, corresponding to those found in the environment, to determine the effectiveness of alpha radiation of different energies. Preparation of sample targets is discussed, including the use of absolute ethanol, thorough etching and deposition by centrifuge. Preliminary results show that the alpha/gamma effectiveness ratio, k, depends on the energy of the incident alpha and must therefore be expressed in terms of a reference energy. The effectiveness of an alpha particle in causing ESR damage is found to vary linearly with its range or path length, not with its energy, a fact which must be considered when calculating effective dose-rates from environmental radionuclide concentrations. Failure to do so may lead to serious systematic errors in the effective alpha contribution to environmental dose-rates and consequently in age estimates. (author)

  14. Alpha particle response study of polycrstalline diamond radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit; Topkar, Anita [Electronics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)

    2016-05-23

    Chemical vapor deposition has opened the possibility to grow high purity synthetic diamond at relatively low cost. This has opened up uses of diamond based detectors for wide range of applications. These detectors are most suitable for harsh environments where standard semiconductor detectors cannot work. In this paper, we present the fabrication details and performance study of polycrystalline diamond based radiation detector. Effect of different operating parameters such as bias voltage and shaping time for charge collection on the performance of detector has been studied.

  15. Space radiation effects

    International Nuclear Information System (INIS)

    Li Shiqing; Yan Heping

    1995-01-01

    The authors briefly discusses the radiation environment in near-earth space and it's influences on material, and electronic devices using in space airship, also, the research developments in space radiation effects are introduced

  16. Radiation effects in space

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1986-01-01

    The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented

  17. Matlab fractal techniques used to study the structural degradation caused by alpha radiation to laser mirrors

    Science.gov (United States)

    Ioan, M.-R.

    2018-01-01

    Almost all optical diagnostic systems associated with classical particle accelerators or with new state-of-the-art particle accelerators, such as those developed within the European Collaboration ELI-NP (Extreme Light Infrastructure-Nuclear Physics) (involving extreme power laser beams), contain in their infrastructure high quality laser mirrors, used for their reflectivity and/or their partial transmittance. These high quality mirrors facilitate the extraction and handling of optical signals. When optical mirrors are exposed to high energy ionizing radiation fields, their optical and structural properties will change over time and their functionality will be affected, meaning that they will provide imprecise information. In some experiments, being exposed to mixed laser and accelerated particle beams, the deterioration of laser mirrors is even more acute, since the destruction mechanisms of both types of beams are cumulated. The main task of the work described in this paper was to find a novel specific method to analyse and highlight such degradation processes. By using complex fractal techniques integrated in a MATLAB code, the effects induced by alpha radiation to laser mirrors were studied. The fractal analysis technique represents an alternative approach to the classical Euclidean one. It can be applied for the characterization of the defects occurred in mirrors structure due to their exposure to high energy alpha particle beams. The proposed method may be further integrated into mirrors manufacturing process, as a testing instrument, to obtain better quality mirrors (enhanced resistance to high energy ionizing beams) by using different types of reflective coating materials and different deposition techniques. Moreover, the effect of high energy alpha ionizing particles on the optical properties of the exposed laser mirrors was studied by using spectrophotometric techniques.

  18. Wandering in the Lyman-alpha forest: a study of dark matter-dark radiation interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krall, Rebecca; Cyr-Racine, Francis-Yan; Dvorkin, Cora, E-mail: rkrall@physics.harvard.edu, E-mail: fcyrraci@physics.harvard.edu, E-mail: dvorkin@physics.harvard.edu [Harvard University, Department of Physics, Cambridge, MA 02138 (United States)

    2017-09-01

    The amplitude of large-scale matter fluctuations inferred from the observed Sunyaev-Zeldovich (SZ) cluster mass function and from weak gravitational lensing studies, when taken at face value, is in tension with measurements of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO). In this work, we revisit whether this possible discrepancy can be attributed to new interactions in the dark matter sector. Focusing on a cosmological model where dark matter interacts with a dark radiation species until the epoch of matter-radiation equality, we find that measurements of the Lyman-alpha flux power spectrum from the Sloan Digital Sky Survey provide no support to the hypothesis that new dark matter interactions can resolve the possible tension between CMB and large-scale structure (LSS). Indeed, while the addition of dark matter-dark radiation interactions leads to an improvement of 2ΔlnL=12 with respect to the standard Λ cold dark matter (ΛCDM) model when only CMB, BAO, and LSS data are considered, the inclusion of Lyman-alpha data reduces the improvement of the fit to 2ΔlnL=6 relative to ΛCDM . We thus conclude that the statistical evidence for new dark matter interactions (largely driven by the Planck SZ dataset) is marginal at best, and likely caused by systematics in the data. We also perform a Fisher forecast analysis for the reach of a future dataset composed of a CMB-S4 experiment combined with the Large Synoptic Survey Telescope galaxy survey. We find that the constraint on the effective number of fluid-like dark radiation species, Δ N {sub fluid}, will be improved by an order of magnitude compared to current bounds.

  19. Wandering in the Lyman-alpha forest: a study of dark matter-dark radiation interactions

    International Nuclear Information System (INIS)

    Krall, Rebecca; Cyr-Racine, Francis-Yan; Dvorkin, Cora

    2017-01-01

    The amplitude of large-scale matter fluctuations inferred from the observed Sunyaev-Zeldovich (SZ) cluster mass function and from weak gravitational lensing studies, when taken at face value, is in tension with measurements of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO). In this work, we revisit whether this possible discrepancy can be attributed to new interactions in the dark matter sector. Focusing on a cosmological model where dark matter interacts with a dark radiation species until the epoch of matter-radiation equality, we find that measurements of the Lyman-alpha flux power spectrum from the Sloan Digital Sky Survey provide no support to the hypothesis that new dark matter interactions can resolve the possible tension between CMB and large-scale structure (LSS). Indeed, while the addition of dark matter-dark radiation interactions leads to an improvement of 2ΔlnL=12 with respect to the standard Λ cold dark matter (ΛCDM) model when only CMB, BAO, and LSS data are considered, the inclusion of Lyman-alpha data reduces the improvement of the fit to 2ΔlnL=6 relative to ΛCDM . We thus conclude that the statistical evidence for new dark matter interactions (largely driven by the Planck SZ dataset) is marginal at best, and likely caused by systematics in the data. We also perform a Fisher forecast analysis for the reach of a future dataset composed of a CMB-S4 experiment combined with the Large Synoptic Survey Telescope galaxy survey. We find that the constraint on the effective number of fluid-like dark radiation species, Δ N fluid , will be improved by an order of magnitude compared to current bounds.

  20. Development of optical monitor of alpha radiations based on CR-39.

    Science.gov (United States)

    Joshirao, Pranav M; Shin, Jae Won; Vyas, Chirag K; Kulkarni, Atul D; Kim, Hojoong; Kim, Taesung; Hong, Seung-Woo; Manchanda, Vijay K

    2013-11-01

    Fukushima accident has highlighted the need to intensify efforts to develop sensitive detectors to monitor the release of alpha emitting radionuclides in the environment caused by the meltdown of the discharged spent fuel. Conventionally, proportional counting, scintillation counting and alpha spectrometry are employed to assay the alpha emitting radionuclides but these techniques are difficult to be configured for online operations. Solid State Nuclear Track Detectors (SSNTDs) offer an alternative off line sensitive technique to measure alpha emitters as well as fissile radionuclides at ultra-trace level in the environment. Recently, our group has reported the first ever attempt to use reflectance based fiber optic sensor (FOS) to quantify the alpha radiations emitted from (232)Th. In the present work, an effort has been made to develop an online FOS to monitor alpha radiations emitted from (241)Am source employing CR-39 as detector. Here, we report the optical response of CR-39 (on exposure to alpha radiations) employing techniques such as Atomic Force Microscopy (AFM) and Reflectance Spectroscopy. In the present work GEANT4 simulation of transport of alpha particles in the detector has also been carried out. Simulation includes validation test wherein the projected ranges of alpha particles in the air, polystyrene and CR-39 were calculated and were found to agree with the literature values. An attempt has been further made to compute the fluence as a function of the incidence angle and incidence energy of alphas. There was an excellent correlation in experimentally observed track density with the simulated fluence. The present work offers a novel approach to design an online CR-39 based fiber optic sensor (CRFOS) to measure the release of nanogram quantity of (241)Am in the environment. © 2013 Elsevier Ltd. All rights reserved.

  1. Biological radiation effects

    International Nuclear Information System (INIS)

    Gomes, R.A.

    1976-01-01

    The stages of processes leading to radiation damage are studied, as well as, the direct and indirect mechanics of its production. The radiation effects on nucleic acid and protein macro moleculas are treated. The physical and chemical factors that modify radiosensibility are analysed, in particular the oxygen effects, the sensibilization by analogues of nitrogen bases, post-effects, chemical protection and inherent cell factors. Consideration is given to restoration processes by excision of injured fragments, the bloching of the excision restoration processes, the restoration of lesions caused by ionizing radiations and to the restoration by genetic recombination. Referring to somatic effects of radiation, the early ones and the acute syndrome of radiation are discussed. The difference of radiosensibility observed in mammalian cells and main observable alterations in tissues and organs are commented. Referring to delayed radiation effects, carcinogeneses, alterations of life span, effects on growth and development, as well as localized effects, are also discussed [pt

  2. Biological effects of radiation

    International Nuclear Information System (INIS)

    2013-01-01

    This fourth chapter presents: cell structure and metabolism; radiation interaction with biological tissues; steps of the production of biological effect of radiation; radiosensitivity of tissues; classification of biological effects; reversibility, transmissivity and influence factors; pre-natal biological effects; biological effects in therapy and syndrome of acute irradiation

  3. Effect of Pilates Training on Alpha Rhythm

    Directory of Open Access Journals (Sweden)

    Zhijie Bian

    2013-01-01

    Full Text Available In this study, the effect of Pilates training on the brain function was investigated through five case studies. Alpha rhythm changes during the Pilates training over the different regions and the whole brain were mainly analyzed, including power spectral density and global synchronization index (GSI. It was found that the neural network of the brain was more active, and the synchronization strength reduced in the frontal and temporal regions due to the Pilates training. These results supported that the Pilates training is very beneficial for improving brain function or intelligence. These findings maybe give us some line evidence to suggest that the Pilates training is very helpful for the intervention of brain degenerative diseases and cogitative dysfunction rehabilitation.

  4. Effect of Pilates Training on Alpha Rhythm

    Science.gov (United States)

    Bian, Zhijie; Sun, Hongmin; Lu, Chengbiao; Yao, Li; Chen, Shengyong; Li, Xiaoli

    2013-01-01

    In this study, the effect of Pilates training on the brain function was investigated through five case studies. Alpha rhythm changes during the Pilates training over the different regions and the whole brain were mainly analyzed, including power spectral density and global synchronization index (GSI). It was found that the neural network of the brain was more active, and the synchronization strength reduced in the frontal and temporal regions due to the Pilates training. These results supported that the Pilates training is very beneficial for improving brain function or intelligence. These findings maybe give us some line evidence to suggest that the Pilates training is very helpful for the intervention of brain degenerative diseases and cogitative dysfunction rehabilitation. PMID:23861723

  5. Radiation effects in semiconductors

    CERN Document Server

    2011-01-01

    There is a need to understand and combat potential radiation damage problems in semiconductor devices and circuits. Written by international experts, this book explains the effects of radiation on semiconductor devices, radiation detectors, and electronic devices and components. These contributors explore emerging applications, detector technologies, circuit design techniques, new materials, and innovative system approaches. The text focuses on how the technology is being used rather than the mathematical foundations behind it. It covers CMOS radiation-tolerant circuit implementations, CMOS pr

  6. Radiation Therapy Side Effects

    Science.gov (United States)

    Radiation therapy has side effects because it not only kills or slows the growth of cancer cells, it can also affect nearby healthy cells. Many people who get radiation therapy experience fatigue. Other side effects depend on the part of the body that is being treated. Learn more about possible side effects.

  7. Integral alpha and gamma radiation measurements in dwelling houses

    International Nuclear Information System (INIS)

    Paripas, B.; Takacs, S.; Somogyi, G.; Nikl, I.

    1984-01-01

    A solid state nuclear track detector method is applied to determine radon and total alpha-exposures (time integral of activity concentrations). The mathematical description of the method of measurement by a passive device equipped with two plastic sheets is presented. Measurements have been carried out in 88 houses over a five-month period and in 20 houses every season for a whole year. Simultaneously with the seasonal measurements of alpha-exposures, the gamma doses were also determined by means of TL dosemeters. The mean exposures due to thoron and its progeny have been estimated by statistical methods. A possible connection between the measured quantities and the lung cancer rates in two settlements were examined. (Author)

  8. Measuring space radiation shielding effectiveness

    Directory of Open Access Journals (Sweden)

    Bahadori Amir

    2017-01-01

    Full Text Available Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  9. Measuring space radiation shielding effectiveness

    Science.gov (United States)

    Bahadori, Amir; Semones, Edward; Ewert, Michael; Broyan, James; Walker, Steven

    2017-09-01

    Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  10. Radiation effects on polyaniline

    International Nuclear Information System (INIS)

    Oki, Yuichi; Kondo, Kenjiro; Suzuki, Takenori; Numajiri, Masaharu; Miura, Taichi; Doi, Shuji; Ohnishi, Toshihiro.

    1992-01-01

    Effects of γ-irradiation on electrical conductivity of polyaniline were investigated. A drastic increase of the conductivity due to radiation-induced doping was observed in combined systems of polyaniline films and halogen-containing polymers. This effect can be applied to measure an integrated radiation dose. (author)

  11. Radiation effects in space

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs

  12. Radiation effects and radioprotectors

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, R.K., E-mail: dr_rajendra_purohit@yahoo.co.in [Radiation Biology Laboratory, Department of Zoology, Govt. Dungar College, Bikaner (India); Bugalia, Saroj [Department of Zoology, S.K. Kalyan College, Sikar (India); Dakshene, Monika [Department of Chemistry, Govt. College, Kota (India)

    2012-07-01

    Radiation exposure causes damage to biological systems and these damages are mediated by the generation of free radicals and reactive oxygen species targeting vital cellular components such as DNA and membranes. DNA repair systems and the endogenous cellular biochemical defense mechanisms against reactive oxygen species and antioxidants enzymes like reduced Glutathione (GSH), Superoxide dismutase, Glutathione peroxidase catalase etc. fail upon exposures to higher as well as chronic radiation doses leading to alterations in cell functions, cell death or mutations. Radioprotectors prevent these alterations and protect cells and tissues from the deleterious effects of radiations. Radioprotectors are of great importance due to their possible and potential application during planned radiation exposures such as radiotherapy, diagnostic scanning, clean up operations in nuclear accidents, space expeditions etc. and Unplanned radiations exposures such as accidents in nuclear industry, nuclear terrorism, natural background radiation etc. Many of the available synthetic radioprotectors are toxic to mammalian system at doses required to be effective as radioprotector. Increasing uses of ionizing radiation have drawn the attention of many radiobiologists towards their undesired side effects produced in various tissues and for modifying them to facilitate the beneficial uses of radiation. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Radioprotectors are chemicals that modify a cell's response to radiation. Radioprotectors are drugs that protect normal (non cancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation. Various chemicals, like Cysteamine, MPG , WR-2721 have been tested for the protection against harmful effects of radiation. These radio

  13. Radiation effects and radioprotectors

    International Nuclear Information System (INIS)

    Purohit, R.K.; Bugalia, Saroj; Dakshene, Monika

    2012-01-01

    Radiation exposure causes damage to biological systems and these damages are mediated by the generation of free radicals and reactive oxygen species targeting vital cellular components such as DNA and membranes. DNA repair systems and the endogenous cellular biochemical defense mechanisms against reactive oxygen species and antioxidants enzymes like reduced Glutathione (GSH), Superoxide dismutase, Glutathione peroxidase catalase etc. fail upon exposures to higher as well as chronic radiation doses leading to alterations in cell functions, cell death or mutations. Radioprotectors prevent these alterations and protect cells and tissues from the deleterious effects of radiations. Radioprotectors are of great importance due to their possible and potential application during planned radiation exposures such as radiotherapy, diagnostic scanning, clean up operations in nuclear accidents, space expeditions etc. and Unplanned radiations exposures such as accidents in nuclear industry, nuclear terrorism, natural background radiation etc. Many of the available synthetic radioprotectors are toxic to mammalian system at doses required to be effective as radioprotector. Increasing uses of ionizing radiation have drawn the attention of many radiobiologists towards their undesired side effects produced in various tissues and for modifying them to facilitate the beneficial uses of radiation. Modification of radiation response is obtained by means of chemical substances that can significantly decrease the magnitude of response when present in a biological system during irradiation. Radioprotectors are chemicals that modify a cell's response to radiation. Radioprotectors are drugs that protect normal (non cancerous) cells from the damage caused by radiation therapy. These agents promote the repair of normal cells that are exposed to radiation. Various chemicals, like Cysteamine, MPG , WR-2721 have been tested for the protection against harmful effects of radiation. These radio

  14. Man and radiation effects

    International Nuclear Information System (INIS)

    Rausch, L.

    1982-01-01

    The book describes the effects of ionizing radiation on man in a simple, popular, detailed and generally valid manner and gives a comprehensive picture of the concepts, elements, principles of function, and perspectives of medical radiobiology. Radiobiology in general is explained, and its application in research on the causes of radiolesions and radiation diseases as well as a radiotherapy and radiation protection is discussed in popular form. (orig./MG) [de

  15. Biological radiation effects

    International Nuclear Information System (INIS)

    Kiefer, J.

    1989-01-01

    The book covers all aspects of biological radiation effects. The physical basis is dealt with in some detail, and the effects at the subcellular and the cellular level are discussed, taking into account modern developments and techniques. The effects on the human organism are reviewed, both from the point of view of applications in medicine as well as with regard to radiation hazards (teratogenic, gonadal and carcinogenic effects)

  16. Effects of isotropic alpha populations on tokamak ballooning stability

    International Nuclear Information System (INIS)

    Spong, D.A.; Sigmar, D.J.; Tsang, K.T.; Ramos, J.J.; Hastings, D.E.; Cooper, W.A.

    1986-12-01

    Fusion product alpha populations can significantly influence tokamak stability due to coupling between the trapped alpha precessional drift and the kinetic ballooning mode frequency. Careful, quantitative evaluations of these effects are necessary in burning plasma devices such as the Tokamak Fusion Test Reactor and the Joint European Torus, and we have continued systematic development of such a kinetic stability model. In this model we have considered a range of different forms for the alpha distribution function and the tokamak equilibrium. Both Maxwellian and slowing-down models have been used for the alpha energy dependence while deeply trapped and, more recently, isotropic pitch angle dependences have been examined

  17. Effective liquid drop description for alpha decay of atomic nuclei

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Duarte, S.B.; Rodriguez, O.; Guzman, F.; Goncalves, M.; Garcia, F.

    1998-06-01

    Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author)

  18. The measurement of alpha, beta and gamma radiations

    International Nuclear Information System (INIS)

    Burns, P.A.

    1982-01-01

    Detection methods for nuclear radiations are based on the processes of excitation and ionization of atoms in the detection medium by the passage of a charged particle. Detectors are usually of two types, those which produce a charge pulse following ionization of the medium and those which produce a burst of light photons which are then detected by a photomultiplier tube. By processing the electronic signals produced in suitable ways either the count rate of the source, the activity, or the dose equivalent to a person may be determined. In order to make these determinations it is necessary to understand the type of nuclear transformation of the radionuclide in question, the type and energy of the radiation being emitted and the processes involved when these radiations pass through the medium of the detector. Suitable choice of detectors and extrapolation from measured data to the quantity which is to be determined can then be made

  19. [Effect of alpha dihydroergocryptine in patients with fibrocystic breast disease].

    Science.gov (United States)

    Castillo, Eugenio; Garibay, Miguel; Mirabent, Felio

    2006-11-01

    To evaluate the effectiveness of alpha dihidroergocriptine in patients with fibrocystic mastopathy. Patients with diagnosis of fibrocystic breast disease were included in a prospective longitudinal blind double, controlled with placebo study. Patients were randomly assigned to one of two treatment groups: of treatment group A: Alpha dihidroergocriptine tablets of 10 mg, group B: Placebo, during 6 months. After to basal evaluation, the patients were revised in a monthly way evaluating the following symptoms and signs: mastalgia, mammary tension, presence of nodules, nipple secretion, and the presence of adverse events. 39 patients with alpha dihidroergocriptine and 38 with placebo. Mastodinia, a satisfactory response was observed in 100% of alpha dihidroergocriptine group vs 61.11% of placebo group (p = 0.0002). Mastalgia responded in 100% of alpha dihidroergocriptine group vs 64.86% of placebo group (p = 0.0003). Galactorrea responded 100% of alpha dihidroergocriptine group vs 93.33% of the placebo. The nodules in the group alpha dihidroergocriptine disappeared in 23.1% and in 21.1% of the placebo group. Ultrasound evaluation of the nodules did not show significant differences between both groups. Prolactin levels showed a decrease in the group treated with alpha dihidroergocriptine with an important difference between both groups at the end of the 6 months study period. There were not differences in the presence of adverse events between groups. Alpha dihidroergocriptine is effective in the treatment of fribrocystic breast disease with minimum adverse events when compared with similar drugs.

  20. Biophysical radiation effects

    International Nuclear Information System (INIS)

    Fidorra, J.

    1982-07-01

    The biological effectiveness of ionizing radiation is based upon the absorption of energy in molecular structures of a cell. Because of the quantum nature of radiation large fluctuations of energy concentration in subcellulare regions has to be considered. In addition both the spatial distribution of a sensitive molecular target and cellulare repair processes has to be taken into consideration for an assessment of radiation action. In radiation protection the difference between the quality factor and the Relative Biological Effectiveness has a fundamental meaning and will be discussed in more detail. The present report includes a short review on some relevant models on radiation action and a short discussion on effects of low dose irradiation. (orig.) [de

  1. Old and new versions of the alpha radiation theory of petroleum origin

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    1981-03-01

    Some aspects of petroleum formation and the world distribution of fossil fuels deposits were recent clarified. However, the source of energy associated with petroleum genesis is still largely debatable. Evidence accumulated over the years allows to demonstrate the energetic feasibility of a modern version of the old alpha radiation theory of petroleum origin. This theory is reviewed and examined critically under new light to be reformulated by taking advantage of relevant interdisciplinary data mostly not available when the old alpha radiation theory was suggested, developed and then discredited. The geological ages accepted for the formation of most of the known petroleum reserves are within a range that makes long-lived natural alpha emitters a feasible energy source for at least part of the energy necessary for the formation of petroleum hydrocarbon. (author) [pt

  2. Radiation effects in gases

    International Nuclear Information System (INIS)

    Leonhardt, J.W.

    1985-01-01

    Problems in the studies of radiation effects in gases are discussed. By means of ionization- excitation- and electron-capture yields various applications are characterized: ionization detectors, X-ray detectors, radionuclide battery, and radiation-induced chemical gas-phase reactions. Some new results of basic research in respect to the SO 2 oxidation are discussed. (author)

  3. Effects of ionizing radiations

    International Nuclear Information System (INIS)

    Gaussens, G.

    1984-08-01

    After recalling radiation-matter interaction, influence on radiation effects of chemical composition, structure, irradiation atmosphere, dose rate, temperature of organic materials and evolution of electrical, mechanical and physical properties are reviewed. Then behaviour under irradiation of main organic materials: elastomers, thermoplastics, thermosetting plastics, oils and paints are examined. 68 refs [fr

  4. Geometric effects in alpha particle detection from distributed air sources

    International Nuclear Information System (INIS)

    Gil, L.R.; Leitao, R.M.S.; Marques, A.; Rivera, A.

    1994-08-01

    Geometric effects associated to detection of alpha particles from distributed air sources, as it happens in Radon and Thoron measurements, are revisited. The volume outside which no alpha particle may reach the entrance window of the detector is defined and determined analytically for rectangular and cylindrical symmetry geometries. (author). 3 figs

  5. Protective Role of Alpha Lipoic Acid Against Disorders Induced by Gamma Radiation

    International Nuclear Information System (INIS)

    Abd El Azeem, Kh.N.M.

    2011-01-01

    Ionizing radiation interacts with living cells, causing a variety of biochemical changes depending on exposed and absorbed doses, duration of exposure, interval after exposure and susceptibility of tissues to ionizing radiation. So, it may increase the oxidative stress and damage of body organs. Alpha-lipoic acid (ALA-also known as thioctic acid) appears to be readily absorbed from an oral dose and converts easily to its reduced form, dihydro lipoic acid (DHLA), in many tissues of the body. ALA can neutralize free radicals in both fatty and watery regions of cells. The present study has been designed to evaluate the possible efficiency of ALA as antioxidant and radio-protector against radiation induced oxidative stress in different organs (liver, kidney and heart) in rats through estimation of the activity of markers of serum liver, kidney and heart function, in addition to the histopathological differentiation of these organs by light and electron microscope. Five equal groups were conducted for the study: control, ALA (30 mg/kg body wt), irradiated (each rat was exposed to 6 Gy as a fractionated dose of gamma (γ) radiation), irradiated plus ALA (each rat received ALA for 9 days simultaneously during exposure) and ALA plus irradiation plus ALA groups (each rat received ALA for a week pre-exposure plus 9 days during exposure). Radiation doses were fractionated dose levels of 2 Gy each 3 days to reach accumulative dose of 6 Gy. After 3 days of each exposure rats were sacrificed, except, those left for recovery test one month after last exposure. The results revealed that whole body γ-irradiation of rats induces oxidative stress in liver, kidney and heart obviously manifested by significant elevation in alanine and aspartate transaminase ( ALT and AST), alkaline phosphatase (ALP), urea, creatinine and creatine kinase (CK-MB). ALA treated-irradiated rats showed lower significantly values indicating remarkable improvement in all measured parameters and

  6. Maintenance experiences with hand and foot monitor for monitoring alpha and beta radiation of personnel in NFC

    International Nuclear Information System (INIS)

    Ramachandra Rao, A.; Kulkarni, R.S.; Banerjee, P.K.

    2010-01-01

    NFC is producing natural uranium and enriched uranium fuels for various reactors including PHWR etc. Monitoring of α and β radiations in the active plants of NFC is very much essential in many aspects. The personnel who are handling radiation materials have to be monitored for α radiation of hands and cloths and β radiation of feet. So the Alpha and Beta Monitor became important monitoring equipment for monitoring α and β radiations of persons working in active plants of NFC. Many Alpha and Beta Monitors of make, ECIL, PLA, and Nucleonix etc. were being used in active plants in NFC. Basically α and β radiation monitors consists of four PMT (Photo Multiplier Tubes) for detection of radiation of hands and one PMT for monitoring clothes. The PMT use ZnS (Ag) as the scintillator for detection of α radiation. GM tubes are used to detect β radiation of feet. The latest Hand and Foot Monitors have been incorporated with PC based monitoring system along with software for making the monitoring process more efficient and user friendly. As an instrumentation maintenance team for these monitors, our experiences are varied. These monitors are to be periodically maintained and tested for its effective functioning in monitoring the nuclear radiation. The monitors procured from M/s. ECIL were being used since long time in these areas. The instrumentation maintenance had faced some problems with these monitors such as frequent failure of High Voltage cards, Amplifier and Counter PCB cards. Modifications were made in the circuits of High Voltage and Counter cards to minimize the failure rate and for loading of Display and Monitoring Software through Hard disk instead of from floppy disk. So the availability of monitors for monitoring radiation got improved. Later the introduction of more sophisticated α and β radiation monitors of M/s. PLA make in these areas further improved monitoring of radiation of personnel working in active areas. These monitors are more user

  7. Effects of alpha populations on tokamak ballooning stability

    International Nuclear Information System (INIS)

    Spong, D.A.; Sigmar, D.J.; Tsang, K.T.; Ramos, J.J.; Hastings, D.E.; Cooper, W.A.

    1986-01-01

    Fusion product alpha populations can significantly influence tokamak stability due to coupling between the trapped alpha precessional drift and the kinetic ballooning mode frequency. This effect is of particular importance in parameter regimes where the alpha pressure gradient begins to constitute a sizable fraction of the thermal plasma pressure gradient. Careful, quantitative evaluations of these effects are necessary in burning plasma devices such as the Tokamak Fusion Test Reactor and the Joint European Torus, and we have continued systematic development of such a kinetic stability model. In this model we have considered a range of different forms for the alpha distribution function and the tokamak equilibrium. Both Maxwellian and slowing-down models have been used for the alpha energy dependence while deeply trapped and, more recently, isotropic pitch angle dependence have been examined

  8. Ionizing radiation, radiation sources, radiation exposure, radiation effects. Pt. 2

    International Nuclear Information System (INIS)

    Schultz, E.

    1985-01-01

    Part 2 deals with radiation exposure due to artificial radiation sources. The article describes X-ray diagnosis complete with an analysis of major methods, nuclear-medical diagnosis, percutaneous radiation therapy, isotope therapy, radiation from industrial generation of nucler energy and other sources of ionizing radiation. In conclusion, the authors attempt to asses total dose, genetically significant dose and various hazards of total radiation exposure by means of a summation of all radiation impacts. (orig./WU) [de

  9. Non controlled effect of ionizing radiations : involvement for radiation protection

    International Nuclear Information System (INIS)

    Little, J. B.

    2005-01-01

    It is widely accepted that damage to DNA is the critical event on irradiated cells, and that double strand breaks are the primary DNA lesions responsible for the biological effects of ionizing radiation. This has lead to the long standing paradigm that these effects, be they cytotoxicity, mutagenesis or malignant transformation, occur in irradiated cells as a consequences of the DNA damage they incur. Evidence has been accumulating over the past decade, however, to indicate that radiation may induce effects that ar not targeted to the irradiated cells itself. Two non-targeted effects will be described in this review. The first, radiation-induced genomic instability, is a phenomenon whereby signals are transmitted to the progeny of the irradiated cell over many generations, leading to the occurrence of genetic effects such as mutations and chromosomal aberrations arising in the distant descendants of the irradiated cell. Second, the bystander effect, is a phenomenon whereby irradiated cells transmit damage signals to non-irradiated cells in a mixed population, leading to genetic effects arising in these bystander cells that received no radiation exposure. the model system described in this review involves dense monolayer cultures exposed to very low fluences of alpha particles. The potential implications of these two phenomena for the analysis of the risk to the human population of exposure to low levels of ionising radiation is discussed. (Author) 111 refs

  10. Health effects of radiation damage

    International Nuclear Information System (INIS)

    Gasimova, K; Azizova, F; Mehdieva, K.

    2012-01-01

    Full text : A summary of the nature of radiactive contamination would be incomplete without some mention of the human health effects relatied to radioactivity and radioactive materials. Several excellent reviews at the variety of levels of detail have been written and should be consulted by the reader. Internal exposures of alpha and beta particles are important for ingested and inhaled radionuclides. Dosimetry models are used to estimate the dose from internally deposited radioactive particles. As mentioned above weighting parameters that take into account the radiation type, the biological half-life and the tissue or organ at risk are used to convert the physically absorbed dose in units of gray (or red) to the biologically significant committed equivalent dose and effective dose, measured in units of Sv (or rem). There is considerable controversy over the shape of the dose-response curve at the chronic low dose levels important for enviromental contamination. Proposed models include linear models, non-linear models and threshold models. Because risks at low dose must be extrapolated from available date at high doses, the shape of the dose-response curve has important implications for the environmental regulations used to protect the general public. The health effect of radiation damage depends on a combination of events of on the cellular, tissue and systemic levels. These lead to mutations and cellular of the irradiated parent cell. The dose level at which significant damage occurs depends on the cell type. Cells that reproduce rapidily, such as those found in bone marrow or the gastrointestinal tract, will be more sensitive to radiation than those that are longer lived, such as striated muscle or nerve cells. The effects of high radiation doses on an organ depends on the various cell types it contains

  11. Low dose radiation and ALARA: the potential risks to patients and staff from alpha-therapy

    International Nuclear Information System (INIS)

    Priest, N.D.

    2014-01-01

    This year a new drug containing radium-223, an alpha-emitting radionuclide, was approved for use by the US Food and Drug Administration for the palliative treatment of advanced prostate cancer metastases. Other drugs containing short-lived alpha-emitters are on clinical trial in Europe. Commonly, these employ a radionuclide attached to an antibody that specifically targets tumor cells to produce a highly localized radio-therapeutic dose to the tumor. However, normal tissues within the body will also be irradiated, albeit sometimes at low dose, and the question arises as to whether this presents a significant additional risk to the patient. Similarly, medical staff that handle these radionuclides could receive intakes of the radionuclides. What is the risk to staff? To assess the risk resulting from small tissue alpha-doses the toxicological, both human and animal, database was re-examined. The results of 20 epidemiological and toxicological studies with alpha-emitting radionuclides were analysed. In all cases a polynomial function provided a better fit to the data than a linear, no thresholds function. Also, in 19 cases a threshold dose below which no cancer is seen was indicated. The position of this threshold varied according to cancer type, but was typically in the range 0.1 to 1.0Gy of tissue dose - with a mean of 0.5Gy. It is concluded that alpha-radiation induced tumorogenesis is a threshold response and that as long as tissue doses are kept below these thresholds no additional cancers would be seen in either patients receiving alpha-therapy or in staff exposed to 'spilt' radionuclide. The presence of thresholds questions the appropriateness of current ALARA practices that are mostly used to drive occupational alpha-radiation exposures to as close to zero as possible. (author)

  12. Low dose radiation and ALARA: the potential risks to patients and staff from alpha-therapy

    Energy Technology Data Exchange (ETDEWEB)

    Priest, N.D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    This year a new drug containing radium-223, an alpha-emitting radionuclide, was approved for use by the US Food and Drug Administration for the palliative treatment of advanced prostate cancer metastases. Other drugs containing short-lived alpha-emitters are on clinical trial in Europe. Commonly, these employ a radionuclide attached to an antibody that specifically targets tumor cells to produce a highly localized radio-therapeutic dose to the tumor. However, normal tissues within the body will also be irradiated, albeit sometimes at low dose, and the question arises as to whether this presents a significant additional risk to the patient. Similarly, medical staff that handle these radionuclides could receive intakes of the radionuclides. What is the risk to staff? To assess the risk resulting from small tissue alpha-doses the toxicological, both human and animal, database was re-examined. The results of 20 epidemiological and toxicological studies with alpha-emitting radionuclides were analysed. In all cases a polynomial function provided a better fit to the data than a linear, no thresholds function. Also, in 19 cases a threshold dose below which no cancer is seen was indicated. The position of this threshold varied according to cancer type, but was typically in the range 0.1 to 1.0Gy of tissue dose - with a mean of 0.5Gy. It is concluded that alpha-radiation induced tumorogenesis is a threshold response and that as long as tissue doses are kept below these thresholds no additional cancers would be seen in either patients receiving alpha-therapy or in staff exposed to 'spilt' radionuclide. The presence of thresholds questions the appropriateness of current ALARA practices that are mostly used to drive occupational alpha-radiation exposures to as close to zero as possible. (author)

  13. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    International Nuclear Information System (INIS)

    Wong, T.P.W.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2009-01-01

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  14. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  15. Human cytogenetic dosimetry: a dose-response relationship for alpha particle radiation from 241Am

    International Nuclear Information System (INIS)

    DuFrain, R.J.; Littlefield, L.G.; Joiner, E.E.; Frome, E.L.

    1979-01-01

    Cytogenetic dosimetry estimates to guide treatment of persons internally contaminated with transuranic elements have not previously been possible because appropriate in vitro dose-response curves specifically for alpha particle irradiation of human lymphocytes do not exist. Using well-controlled cytogenetic methods for human lymphocyte culture, an experimentally derived dose-response curve for 241 Am alpha particle (5.49 and 5.44 MeV) radiation of G 0 lymphocytes was generated. Cells were exposed to 43.8, 87.7, 175.3 or 350.6 nCi/ml 241 Am for 1.7 hr giving doses of 0.85, 1.71, 3.42 or 6.84 rad. Based on dicentric chromosome yield, the linear dose-response equation is Y = 4.90(+-0.42) x 10 -2 X, with Y given as dicentrics per cell and X as dose in rads. The study also shows that the two-break asymmetrical exchanges in cells damaged by alpha particle radiation are overdispersed when compared to a Poisson distribution. An example is presented to show how the derived dose-response equation can be used to estimate the radiation dose for a person internally contaminated with an actinide. An experimentally derived RBE value of 118 at 0.85 rad is calculated for the efficiency of 241 Am alpha particle induction of dicentric chromosomes in human G 0 lymphocytes as compared with the efficiency of 60 Co gamma radiation. The maximum theoretical value for the RBE for cytogenetic damage from alpha irradiation was determined to be 278 at 0.1 rad or less which is in marked contrast to previously reported RBE values of approx. 20. (author)

  16. Radiation. Doses, effect, risk

    International Nuclear Information System (INIS)

    Vapirev, E.; Todorov, P.

    1994-12-01

    This book outlines in a popular form the topic of ionizing radiation impacts on living organisms. It contains data gathered by ICRP for a period of 35 years. The essential dosimetry terms and units are presented. Natural and artificial sources of ionizing radiation are described. Possible biological radiation effects and diseases as a consequence of external and internal irradiation at normal and accidental conditions are considered. An assessment of genetic risk for human populations is presented and the concept of 'acceptable risk' is discussed

  17. Utilization of a Si-surface-barrier-detector for alpha-spectrometry and its application in radiation protection for the detection of law alpha-activities

    International Nuclear Information System (INIS)

    Steger, F.; Urbanich, E.; Lovranich, E.; Hefner, A.

    1974-12-01

    Due to the construction of the ''Safeguard Analytical Laboratory''(IAEA), the institute for radiation protection at the Research Center Seibersdorf is interested in a method for the alpha-spectroscopic determination of Pu-239 for personnel and environmental monitoring. Therefore an alpha-spectrometer has been built which will mainly be used for the excretion analysis. The design of the apparatus is described, results of measurements are given and other fields of its application are discussed. (C.R.)

  18. Handbook of radiation effects

    International Nuclear Information System (INIS)

    Holmes-Siedle, A.; Adams, L.

    1993-01-01

    This handbook is intended to serve as a tool for designers of equipment and scientific instruments in cases where they are required to ensure the survival of the equipment in radiation environments. High-technology materials, especially semiconductors and optics, tend to degrade on exposure to radiation in many different ways. Intense high-energy radiation environments are found in nuclear reactors and accelerators, machines for radiation therapy, industrial sterilization, and space. Some engineers have to build equipment which will survive a nuclear explosion from a hostile source. Proper handling of a disaster with radioactive materials requires equipment which depends utterly on semiconductor microelectronics and imaging devices. Thus the technology of radiation-tolerant electronics is an instrument for good social spheres as diverse as disaster planning and the exploration of Mars. In order to design equipment for intense environments like those described above, then degradation from high-energy irradiation must be seen as a basic design parameter. The aim of this handbook is to assist the engineer or student in that thought; to make it possible to write intelligent specifications; to offer some understanding of the complex variety of effects which occur when high-technology components encounter high-energy radiation; and to go thoroughly into the balance of choices of how to alleviate the effects and hence achieve the design aims of the project. Separate abstracts were prepared for 15 chapters of this book

  19. Biological Effects of Ionizing Radiation

    Science.gov (United States)

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  20. Radiation effects on living systems

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1980-10-01

    This bibliography includes papers and reports by Atomic Energy of Canada Limited scientists concerning radiation effects on living systems. It is divided into three sections: Radiobiology, Radiation Biochemistry and Radiation Chemistry. (auth)

  1. Doping of semiconductors using radiation defects produced by irradiation with protons and alpha particles

    International Nuclear Information System (INIS)

    Kozlov, V.A.; Kozlovski, V.V.

    2001-01-01

    One of the modern methods for modifying semiconductors using beams of protons and alpha particles is analyzed; this modification is accomplished by the controlled introduction of radiation defects into the semiconductor. It is shown that doping semiconductors with radiation defects produced by irradiation with light ions opens up fresh opportunities for controlling the properties of semiconducting materials and for the development of new devices designed for optoelectronics, microelectronics, and nanoelectronics based on these materials; these devices differ favorably from those obtained by conventional doping methods, i.e., by diffusion, epitaxy, and ion implantation

  2. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    Price, J.; Wei, W.C.; Chong, C.Y.

    1979-01-01

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size

  3. Cranial nerve damage in patients after alpha (heavy)-particle radiation to the pituitary

    International Nuclear Information System (INIS)

    Price, J.; Wei, W.C.; Chong, C.Y.

    1979-01-01

    The records of 161 patients were reviewed to determine if radiation damage had occurred following cranial irradiation. All of these patients had received alpha-particle radiation to their pituitary glands during the period when this form of therapy was given for diabetic retinopathy. Extraocular muscle palsy developed in 11 of these patients, iridoplegia in six, and fifth nerve damage in six. All of the palsies developed within a short period following their irradiation, and a definite dose relationship was present. The dose rate was approximately 100 rads/min for all cases. Fractionation varied but it is known for all cases

  4. Interaction of alpha radiation with thermally-induced defects in silicon

    International Nuclear Information System (INIS)

    Ali, Akbar; Majid, Abdul

    2008-01-01

    The interaction of radiation-induced defects created by energetic alpha particles and thermally-induced defects in silicon has been studied using a Deep Level Transient Spectroscopy (DLTS) technique. Two thermally-induced defects at energy positions E c -0.48 eV and E c -0.25 eV and three radiation-induced defects E2, E3 and E5 have been observed. The concentration of both of the thermally-induced defects has been observed to increase on irradiation. It has been noted that production rates of the radiation-induced defects are suppressed in the presence of thermally-induced defects. A significant difference in annealing characteristics of thermally-induced defects in the presence of radiation-induced defects has been observed compared to the characteristics measured in pre-irradiated samples

  5. A model for the stepwise radiation inactivation of the alpha 2-dimer of Na,K-ATPase

    Energy Technology Data Exchange (ETDEWEB)

    Norby, J.G.; Jensen, J. (Univ. of Aarhus (Denmark))

    1989-11-25

    This study is a direct continuation of Jensen, J., and Norby. A new model in which we propose that the in situ organization of the Na,K-ATPase alpha-subunit is an alpha 2-dimer and which describes the stepwise degradation by radiation inactivation of this assembly is presented on the basis of the following findings. Radiation inactivation size for alpha-peptide integrity, normal nucleotide, vanadate and ouabain binding, and K-pNPPase activity is close to m(alpha) = 112 kDa; for Na-ATPase activity it is 135 kDa and for Na,K-ATPase activity it increases from 140 to about 195 kDa with increasing assay ATP concentration (equal to increasing average turnover). Normal Tl+ occlusion had the same radiation inactivation size as Vmax for Na,K-ATPase, i.e. about 195 kDa. The binding experiments disclosed radiation-produced molecules with active binding sites but with a lower than normal affinity. Radiation inactivation size for the total binding capacity of ADP and ouabain was therefore smaller than the size of an alpha-peptide, namely about 70 kDa, and for total Tl+ occlusion it was down to 40 kDa. We can explain all these observations by using a new approach to target size analysis and by assuming a dimeric organization of the alpha-subunit. Each alpha-peptide is degraded stepwise by first destruction of either a 42- or a 70-kDa domain, and the partly damaged peptide may retain biochemical activity. We conclude that there is no role for the beta-subunit in catalysis and that the alpha-peptide is organized as an alpha 2-dimer in the membrane with each alpha-subunit being able to perform complete catalytic cycles (and probably also active transport), provided that it is stabilized by an adjacent alpha-peptide or a sufficiently large fragment thereof.

  6. A model for the stepwise radiation inactivation of the alpha 2-dimer of Na,K-ATPase

    International Nuclear Information System (INIS)

    Norby, J.G.; Jensen, J.

    1989-01-01

    This study is a direct continuation of Jensen, J., and Norby. A new model in which we propose that the in situ organization of the Na,K-ATPase alpha-subunit is an alpha 2-dimer and which describes the stepwise degradation by radiation inactivation of this assembly is presented on the basis of the following findings. Radiation inactivation size for alpha-peptide integrity, normal nucleotide, vanadate and ouabain binding, and K-pNPPase activity is close to m(alpha) = 112 kDa; for Na-ATPase activity it is 135 kDa and for Na,K-ATPase activity it increases from 140 to about 195 kDa with increasing assay ATP concentration (equal to increasing average turnover). Normal Tl+ occlusion had the same radiation inactivation size as Vmax for Na,K-ATPase, i.e. about 195 kDa. The binding experiments disclosed radiation-produced molecules with active binding sites but with a lower than normal affinity. Radiation inactivation size for the total binding capacity of ADP and ouabain was therefore smaller than the size of an alpha-peptide, namely about 70 kDa, and for total Tl+ occlusion it was down to 40 kDa. We can explain all these observations by using a new approach to target size analysis and by assuming a dimeric organization of the alpha-subunit. Each alpha-peptide is degraded stepwise by first destruction of either a 42- or a 70-kDa domain, and the partly damaged peptide may retain biochemical activity. We conclude that there is no role for the beta-subunit in catalysis and that the alpha-peptide is organized as an alpha 2-dimer in the membrane with each alpha-subunit being able to perform complete catalytic cycles (and probably also active transport), provided that it is stabilized by an adjacent alpha-peptide or a sufficiently large fragment thereof

  7. Study of threshold energy registration of alpha particles on lexan nuclear track detector (passive) by Kr F laser pre-radiation

    International Nuclear Information System (INIS)

    Parvin, P.; Jaleh, B.; Hashemi, M. M.; Katoozi, M.; Amiri Rad, N.; Zamanipour, Z.; Zarea, A.

    2002-01-01

    The effect of Kr F laser pre-radiation has been investigated on both alpha track density and threshold energy of track registration. While no significant difference was observed on track density an nevertheless ∼100 keV shift of threshold energy occurred due to UV superficial hardening of Lexan detector

  8. Effects of alpha-particles on survival and chromosomal aberrations in human mammary epithelial cells

    Science.gov (United States)

    Durante, M.; Grossi, G. F.; Gialanella, G.; Pugliese, M.; Nappo, M.; Yang, T. C.

    1995-01-01

    We have studied the radiation responses of a human mammary epithelial cell line, H184B5 F5-1 M/10. This cell line was derived from primary mammary cells after treatment with chemicals and heavy ions. The F5-1 M/10 cells are immortal, density-inhibited in growth, and non-tumorigenic in athymic nude mice and represent an in vitro model of the human epithelium for radiation studies. Because epithelial cells are the target of alpha-particles emitted from radon daughters, we concentrated our studies on the efficiency of alpha-particles. Confluent cultures of M/10 cells were exposed to accelerated alpha-particles [beam energy incident at the cell monolayer = 3.85 MeV, incident linear energy transfer (LET) in cell = 109 keV/microns] and, for comparison, to 80 kVp x-rays. The following endpoints were studied: (1) survival, (2) chromosome aberrations at the first postirradiation mitosis, and (3) chromosome alterations at later passages following irradiation. The survival curve was exponential for alpha-particles (D0 = 0.73 +/- 0.04 Gy), while a shoulder was observed for x-rays (alpha/beta = 2.9 Gy; D0 = 2.5 Gy, extrapolation number 1.6). The relative biological effectiveness (RBE) of high-LET alpha-particles for human epithelial cell killing was 3.3 at 37% survival. Dose-response curves for the induction of chromosome aberrations were linear for alpha-particles and linearquadratic for x-rays. The RBE for the induction of chromosome aberrations varied with the type of aberration scored and was high (about 5) for chromosome breaks and low (about 2) for chromosome exchanges.(ABSTRACT TRUNCATED AT 250 WORDS).

  9. Effective liquid drop description for alpha decay of atomic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, O.A.P.; Duarte, S.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencia y Tecnologia Nuclear (ISCTN), La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1998-06-01

    Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author) 44 refs., 5 figs., 3 tabs.; e-mail: telo at ird.gov.br

  10. Effect of alpha1-blockers on stentless ureteroscopic lithotripsy

    Directory of Open Access Journals (Sweden)

    Jianguo Zhu

    2016-02-01

    Full Text Available ABSTRACT Objective To evaluate the clinical efficiency of alpha1-adrenergic antagonists on stentless ureteroscopic lithotripsy treating uncomplicated lower ureteral stones. Materials and Methods From January 2007 to January 2013, 84 patients who have uncomplicated lower ureteral stones treated by ureteroscopic intracorporeal lithotripsy with the holmium laser were analyzed. The patients were divided into two groups, group A (44 patients received indwelled double-J stents and group B (40 patients were treated by alpha1-adrenergic antagonists without stents. All cases of group B were treated with alpha1 blocker for 1 week. Results The mean operative time of group A was significantly longer than group B. The incidences of hematuria, flank/abdominal pain, frequency/urgency after surgery were statistically different between both groups. The stone-free rate of each group was 100%. Conclusions The effect of alpha1-adrenergic antagonists is more significant than indwelling stent after ureteroscopic lithotripsy in treating uncomplicated lower ureteral stones.

  11. Effects of TNF-alpha on Endothelial Cell Collective Migration

    Science.gov (United States)

    Chen, Desu; Wu, Di; Helim Aranda-Espinoza, Jose; Losert, Wolfgang

    2013-03-01

    Tumor necrosis factor (TNF-alpha) is a small cell-signaling protein usually released by monocytes and macrophages during an inflammatory response. Previous work had shown the effects of TNF-alpha on single cell morphology, migration, and biomechanical properties. However, the effect on collective migrations remains unexplored. In this work, we have created scratches on monolayers of human umbilical endothelial cells (HUVECs) treated with 25ng/mL TNF-alpha on glass substrates. The wound healing like processes were imaged with phase contrast microscopy. Quantitative analysis of the collective migration of cells treated with TNF-alpha indicates that these cells maintain their persistent motion and alignment better than untreated cells. In addition, the collective migration was characterized by measuring the amount of non-affine deformations of the wound healing monolayer. We found a lower mean non-affinity and narrower distribution of non-affinities upon TNF-alpha stimulation. These results suggest that TNF-alpha introduces a higher degree of organized cell collective migration.

  12. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Heribanova, A.

    1995-01-01

    The basic principles and pathways of effects of ionizing radiation on living organisms and cells are outlined. The following topics are covered: effects of radiation on living matter (direct effects, radical or indirect effects, dual radiation action, and molecular biological theories); effects of radiation on cells and tissues (cell depletion, changes in the cytogenetic information, reparation mechanisms), dose-response relationship (deterministic effects, stochastic effects), and the effects of radiation on man (acute radiation sickness, acute local changes, fetus injuries, non-tumorous late injuries, malignant tumors, genetic changes). (P.A.). 3 tabs., 2 figs., 5 refs

  13. Radiation effects on superconductivity

    International Nuclear Information System (INIS)

    Brown, B.S.

    1975-01-01

    The effect of radiation on the superconducting transition temperature (T/sub c/), upper critical field (H/sub c2/), and volume-pinning-force density (F/sub p/) were discussed for the three kinds of superconducting material (elements, alloys, and compounds). 11 figures, 3 tables, 86 references

  14. Use of studies with laboratory animals to assess the potential early health effects of combined internal alpha and beta irradiation

    International Nuclear Information System (INIS)

    Scott, B.R.; Hahn, F.F.; Guilmette, R.A.; Muggenburg, B.A.; Snipes, M.B.; Boecker, B.B.; McClellan, R.O.

    1986-01-01

    The potential health impacts of radionuclides released in nuclear accidents are of major concern to the public and to regulatory and other governmental agencies. One mode of potential exposure is by inhalation of airborne radionuclides, which could lead to combined internal irradiation by high (alpha) and low (beta) linear energy transfer (LET) radiations. Epidemiological data for health effects of human inhalation exposure are too limited to derive reliable estimates of risks of potential health effects. However, results of studies in which beagle dogs were exposed by inhalation to insoluble radioactive aerosols can be used to estimate expected effects in humans. Data for mortality from radiation pneumonitis and pulmonary fibrosis caused by internal irradiation of dog lungs by alpha or beta radiations are used to derive the relative biological effectiveness (RBE) of alpha irradiation compared to beta irradiation; predict the expected combined effects of alpha and beta irradiation of dog lungs; and extrapolate the results to humans. The extrapolation to humans assumed that, for similar ages at exposure, dog and human lungs have similar sensitivities to lung irradiation. Results of theoretical calculations related to mortality from early effects indicated that the synergistic effects of high- and low-LET radiations should depend on the percentages of the total dose contributed by high- and low-LET radiations, and for very low or very high doses, synergistic effects should be negligible. 23 refs., 8 figs

  15. Genetic effects of radiation

    International Nuclear Information System (INIS)

    Selby, P.B.

    1977-01-01

    Many of the most important findings concerning the genetic effects of radiation have been obtained in the Biology Division of Oak Ridge National Laboratory. The paper focuses on some of the major discoveries made in the Biology Division and on a new method of research that assesses damage to the skeletons of mice whose fathers were irradiated. The results discussed have considerable influence upon estimates of genetic risk in humans from radiation, and an attempt is made to put the estimated amount of genetic damage caused by projected nuclear power development into its proper perspective

  16. Electron Microscopy Study of Stainless Steel Radiation Damage Due to Long-Term Irradation by Alpha Particles Emitted From Plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Unlu, Kenan [Univ. of Texas, Austin, TX (United States); Rios-Martinez, Carlos [Univ. of Texas, Austin, TX (United States); Saglam, Mehmet [Univ. of Texas, Austin, TX (United States); Hart, Ron R. [Texas A & M Univ., College Station, TX (United States); Shipp, John D. [Texas A & M Univ., College Station, TX (United States); Rennie, John [Texas A & M Univ., College Station, TX (United States)

    1998-04-16

    Radiation damage and associated surface and microstructural changes produced in stainless steel encapsulation by high-fluence alpha particle irradiations from weapons-grade plutonium of 316-stainless steel are being investigated.

  17. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  18. Immunostimulatory effects of natural human interferon-alpha (huIFN-alpha) on carps Cyprinus carpio L.

    Science.gov (United States)

    Watanuki, Hironobu; Chakraborty, Gunimala; Korenaga, Hiroki; Kono, Tomoya; Shivappa, R B; Sakai, Masahiro

    2009-10-15

    Human interferon-alpha (huIFN-alpha) is an important immunomodulatory substance used in the treatment and prevention of numerous infectious and immune-related diseases in animals. However, the immunostimulatory effects of huIFN-alpha in fish remain to be investigated. In the current study, the immune responses of the carp species Cyprinus carpio L. to treatment with huIFN-alpha were analyzed via measurement of superoxide anion production, phagocytic activity and the expression of cytokine genes including interleukin-1beta, tumor necrosis factor-alpha and interleukin 10. Low doses of huIFN-alpha were administered orally once a day for 3 days, and sampling was carried out at 1, 3 and 5 days post-treatment. Our results indicate that a low dose of huIFN-alpha significantly increased phagocytic activity and superoxide anion production in the carp kidney. The huIFN-alpha-treated fish also displayed a significant upregulation in cytokine gene expression. The current study demonstrates the stimulatory effects of huIFN-alpha on the carp immune system and highlights the immunomodulatory role of huIFN-alpha in fish.

  19. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Marko, A.M.

    1981-05-01

    In this review radiation produced by the nuclear industry is placed into context with other sources of radiation in our world. Human health effects of radiation, derivation of standards and risk estimates are reviewed in this document. The implications of exposing the worker and the general population to radiation generated by nuclear power are assessed. Effects of radiation are also reviewed. Finally, gaps in our knowledge concerning radiation are identified and current research on biological effects, on environmental aspects, and on dosimetry of radiation within AECL and Canada is documented in this report. (author)

  20. Two-stream cyclotron radiative instabilities due to the marginally mirror-trapped fraction for fustion alphas in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Arunasalam, V.

    1995-07-01

    It is shown here that the marginally mirror-trapped fraction of the newly-born fusion alpha particles in the deuterium-tritium (DT) reaction dominated tokamak plasmas can induce a two-stream cyclotron radiative instability for the fast Alfven waves propagating near the harmonics of the alpha particle cyclotron frequency {omega}{sub c{alpha}}. This can explain both the experimentally observed time behavior and the spatially localized origin of the fusion product ion cyclotron emission (ICE) in TFTR at frequencies {omega} {approx} m{omega}{sub c{alpha}}.

  1. Rapid appearance of transient secondary adrenocortical insufficiency after alpha-particle radiation therapy for Cushing's disease

    International Nuclear Information System (INIS)

    Cook, D.M.; Jordan, R.M.; Kendall, J.W.; Linfoot, J.A.

    1976-01-01

    A 17-year-old woman received 12,000 rads of alpha-particle radiation for the treatment of Cushing's disease. One day after the completion of therapy, the patient developed nausea, vomiting, headache, and postural hypotension. Laboratory evaluation demonstrated a marked fall of the previously elevated urinary 17-hydroxycorticosteroids (17-OHCS) and undetectable plasma cortisols. The urinary 17-OHCS transiently returned to supranormal levels but over a 2 1 / 2 -week period decreased and then remained low. The patient also demonstrated a subnormal urinary aldosterone excretion in relation to plasma renin activity (PRA) during 10 mEq/24 h sodium restriction. The remainder of the endocrine evaluation was normal, suggesting that pituitary function otherwise remained intact. One and one-half years after alpha-particle therapy, the patient's urinary 17-OHCS were normal and responded normally to metyrapone. The relationship between urinary aldosterone excretion and PRA also was normal. It is postulated that there was an infarction of an ACTH secreting pituitary tumor leaving the remainder of the pituitary intact. A chronically elevated circulating level of ACTH with sudden loss of ACTH secretion appeared to have been responsible for the initial low urinary aldosterone as well as the low urinary 17-OHCS. This is the first reported case of a presumed pituitary tumor infarction in association with alpha-particle pituitary radiation

  2. Control of persistent vesical bleeding due to radiation cytitis by intravesical application of 15(s) 15-methyl prostaglandin F2-alpha

    International Nuclear Information System (INIS)

    Hemal, A.K.; Praveen, B.V.; Sankaranarayanan, A.; Vaidyanathan, S.

    1989-01-01

    A 45 year old female who received radiotherapy for stage II-B uterine cervical cancer four and half years ago, presented with persistent hematuria due to radiation cystitis. 15(S) 15-methyl prostaglandin F 2 -alpha (1 mg in 100 ml of normal saline) was instilled into the bladder daily for two days. The severity of bleeding decreased considerably. However, significant hematuria recurred 19 days later which continued despite bladder irrigation with normal saline, 1 mg of 15(S) 15-Me PGF 2 alpha mixed with hydroxyethyl cellulose gel to a volume of 10 ml was then instilled into the urinary bladder daily for three days and macroscopic hematuria ceased. Urinary frequency and urgency were the side effects which lasted for ten days. There has been no recurrence of macroscopic hematuria during the five months followup. In conclusion, 15(S) 15-Me PGF 2 - alpha may be administered intravesically to control moderate hematuria due to radiation cystitis. (author). 5 refs

  3. Biological effects of alpha particles in lung tissue

    International Nuclear Information System (INIS)

    Hofmann, W.; Daschil, F.

    1985-01-01

    Allowing for concomitant cellular inactivation, the tumour incidence function can be written as the product of two probabilities, for malignant transformation and for not being killed. Cell survival of mammalian cells in culture after heavy ion irradiation has been described successfully by the formalism of track structure theory for cellular inactivation. Thus a transformation function is derived by extracting cellular radiosensitivity parameters from experimental data on mutation to thioguanine resistance. For defined conditions of radon daughter inhalation, from the fraction of inhaled radionuclides deposited and retained on bronchial airway surfaces are calculated. The LET distribution in sensitive bronchial stem cells hit by alpha particles depends on initial alpha particle energy, airway diameter, and stem cell depth. Applying the methodology of track structure theory and using cellular radiosensitivity parameters for cell killing and mutation, the radiation risk at a given stem cell depth is expressed by the probabilities for cellular survival, for mutation or transformation, and the joint probability for cancer induction. (author)

  4. Radiation Effects Research Foundation

    International Nuclear Information System (INIS)

    1979-01-01

    The last day of March 1978 marked the completion of the first 3 years of operation of the Radiation Effects Research Foundation in Hiroshima and Nagasaki. RERF was established on 1 April 1975 as successor to the Atomic Bomb Casualty Commission which had been in continuous operation since 1947. This record of the first 3 years of operation consists of selected reports and other documents prepared in the course of conducting the business of RERF and includes a brief history, a late radiation effects that might be conducted at RERF. The wisdom and thought given to the research program and its operation by the Scientific Council and the Board of Directors is reflected in the minutes of their meetings which are included in the Appendix. (Mori, K.)

  5. Effect of alpha irradiation on UO{sub 2} surface reactivity in aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Jegou, C.; Muzeau, B.; Broudic, V.; Poulesquen, A.; Roudil, D. [Commissariat a l' Energie Atomique (CEA), Rhone Valley Research Center, DIEC/SESC/LMPA, Bagnols-sur-Ceze (France); Jorion, F. [Commissariat a l' Energie Atomique (CEA), Rhone Valley Research Center, DRCP/SE2A/LEMA, Bagnols-sur-Ceze (France); Corbel, C. [Commissariat a l' Energie Atomique (CEA), Saclay Research Center, DSM/DRECAM/SCM, Gif sur Yvette (France)

    2005-07-01

    The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO{sub 2} matrix in aqueous media subjected to {alpha}-{beta}-{gamma} radiation. The {beta}-{gamma} emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO{sub 2} pellets doped with alpha emitters ({sup 238}Pu and {sup 239}Pu) to quantify the impact of alpha irradiation on UO{sub 2} matrix alteration. Three batches of doped UO{sub 2} pellets with different alpha flux levels (3.30 x 10{sup 4}, 3.30 x 10{sup 5}, and 3.2 x 10{sup 6} {alpha} cm{sup -2} s{sup -1}) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO{sub 2} matrix alteration mechanisms under alpha irradiation. Interim storage in air of UO{sub 2} pellets doped with alpha emitters results in variations of the UO{sub 2} surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO{sub 2} pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO{sub 2} to UO{sub 2+x}. However, leaching experiments performed in deaerated media after annealing the samples and

  6. Radiation Bystander Effects Mechanism

    Directory of Open Access Journals (Sweden)

    Shokohzaman Soleymanifard

    2009-06-01

    Full Text Available Introduction: Radiation Induced Bystander Effect (RIBE which cause radiation effects in non-irradiated cells, has challenged the principle according to which radiation traversal through the nucleus of a cell is necessary for producing biological responses. What is the mechanism of this phenomenon? To have a better understanding of this rather ambiguous concept substantial number of original and reviewed article were carefully examined. Results: Irradiated cells release molecules which can propagate in cell environment and/or transmit through gap junction intercellular communication. These molecules can reach to non-irradiated cells and transmit bystander signals. In many investigations, it has been confirmed that these molecules are growth factors, cytokines, nitric oxide and free radicals like reactive oxygen species (ROS. Transmission of by stander signal to neighboring cells persuades them to produce secondary growth factors which in their turn cause further cell injuries. Some investigators suggest, organelles other than nucleus (mitochondria and cell membrane are the origin of these signals.  There is another opinion which suggests double strand breaks (DSB are not directly generated in bystander cells, rather they are due to smaller damage like single strand breaks which accumulate and end up to DSB. Although bystander mechanisms have not been exactly known, it can be confirmed that multiple mechanisms and various pathways are responsible for this effect. Cell type, radiation type, experimental conditions and end points identify the dominant mechanism. Conclusion: Molecules and pathways which are responsible for RIBE, also cause systemic responses to other non-irradiation stresses. So RIBE is a kind of systemic stress or innate immune responses, which are performed by cell microenvironment. Irradiated cells and their signals are components of microenvironment for creating bystander effects.

  7. Radiation effects in metals

    International Nuclear Information System (INIS)

    Leteurtre Jean.

    1978-01-01

    The current understanding of radiation damage in metals is reviewed, simplifying the actual complexity of the effects by considering some aspects separately. The production of point defects in metals, the primary damage state are first studied. The second part of the lecture is devoted to the evolution of this primary damage state as a function of temperature and dose: the steady state concentration of point defects, the nucleation of secondary defects and their growth are successively considered

  8. Temperature thresholds for surface blistering of platinum and stainless steel exposed to curium-242 alpha radiations

    International Nuclear Information System (INIS)

    McDonell, W.R.; Dillich, S.

    1981-01-01

    Implantation of helium in materials exposed to alpha-emitting radionuclides such as 242 Cm causes surface blistering at elevated temperatures. The temperature thresholds for such blistering are of practical importance to the selection of suitable container materials for radionuclides, and are of fundamental interest with regard to the mechanisms of helium blistering of materials in radiation environments. The purpose of this investigation was to establish temperature thresholds for surface blistering of platinum and stainless-steel container materials by post-irradiation heating of specimens exposed at room temperature to alpha particles from an external 242 Cm source. These thresholds were compared with (1) the analogous temperature thresholds for surface blistering of materials exposed to external beams of accelerator helium ions, and (2) thresholds for swelling and grain-boundary cracking of materials in which helium is generated internally by (n,α) reactions during reactor exposures

  9. Alpha radioactivity in tobacco leaves: Effect of fertilizers

    Energy Technology Data Exchange (ETDEWEB)

    Nain, Mahabir [Department of Physics, Government College Karnal, Haryana 132001 (India)], E-mail: mnain@rediffmail.com; Chauhan, R.P. [Department of Physics, National Institute of Technology, Kurukshetra 136119 (India); Chakarvarti, S.K. [Department of Applied Physics, NIT, Kurukshetra 136119 (India)

    2008-08-15

    The link between cigarette smoke and cancer has long been established. Smokers are 10 times at a greater risk of developing lung cancer than that of non-smokers. The toxicity in tobacco is considered mainly due to the presence of chemi-toxins like nicotine, tar, aromatic hydrocarbons, sterols and many other materials leading to mutagenicity and carcinogenicity. There are many reports on the presence of naturally occurring radionuclides viz., {sup 210}Po and {sup 210}Pb in tobacco. Investigations on alpha-emitting radionuclides, especially on {sup 210}Po have gained significant importance as alpha interactions with chromosomes of cells may contribute to early arteriosclerosis developments in tobacco smokers. Due to relatively high activity concentration of {sup 210}Po and {sup 210}Pb that are found in tobacco and its product cigarette can increase the internal intake of both the radionuclides and their concentrations in lung tissues. This causes an increase in the internal radiation dose which enhances the instances of lung cancer. Many workers have tried to explain the role of {sup 210}Po in tobacco in the epidemiological investigation of cancer and tumour formation. In the present work, the estimation of alpha radioactivity in tobacco leaves taken from tobacco plants grown using different types of chemical fertilizers like diammonium phosphate (DAP), zinc sulphate, potash, super phosphate, urea etc. in varying amounts before the plantation of the seedlings has been made. For these measurements we used {alpha}-sensitive LR-115 type II plastic track detectors. The results indicate an increase in alpha radioactivity with the use of some fertilizers.

  10. Lyman-alpha detector designed for rocket measurements of the direct solar radiation at 121.5 nm

    International Nuclear Information System (INIS)

    Guineva, V.; Tashev, V.; Witt, G.; Gumbel, J.; Khaplanov, M.

    2007-01-01

    Rocket measurements of the direct Lyman-alpha radiation penetrating in the atmosphere were planned during the HotPay I rocket experiment, June 2006, Project ASLAF (Attenuation of the Solar Lyman-Alpha Flux), Andoya Rocket Range (ARR), Norway. The basic goal of ASLAF project was the study of the processes in the summer mesosphere and thermosphere (up to 110 km), at high latitudes using the Lyman-alpha measurements. The resonance transition 2 P- 2 S of the atomic hydrogen (Lyman-alpha emission) is the strongest and most conspicuous feature in the solar EUV spectrum. Due to the favourable circumstance, that the Lyman-alpha wavelength (121.5 nm) coincides with a minimum of the O 2 absorption spectrum, the direct Lyman-alpha radiation penetrates well in the mesosphere. The Lyman-alpha radiation is the basic agent of the NO molecules ionization, thus generating the ionospheric D-layer, and of the water vapour photolysis, being one of the main H 2 O loss processes. The Lyman-alpha radiation transfer depends on the resonance scattering from the hydrogen atoms in the atmosphere and on the O 2 absorption. Since the Lyman-alpha extinction in the atmosphere is a measure for the column density of the oxygen molecules, the atmospheric temperature profile can be calculated thereof. The detector of solar Lyman-alpha radiation was manufactured in the Stara Zagora Department of the Solar-Terrestrial Influences Laboratory (STIL). Its basic part is an ionization chamber, filled in with NO. A 60 V power supply is applied to the chamber. The produced photoelectric current from the sensor is fed to a 2-channels amplifier, providing an analogue signal. The characteristics of the Lyman-alpha detector were studied. It passed successfully all tests and the results showed that the instrument could be used in rocket experiments to measure the Lyman-alpha flux. From the measurements of the detector, the Lyman-alpha vertical profile can be obtained. The forthcoming scientific data analysis will

  11. TENORM wastes and the potential alpha radiation dose to aquatic biota

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    2002-01-01

    In the years seventies release-rates and derived limits for releasing radionuclides into the environment were adopted for each particular radionuclide and for a number of pathways. The release-rate limit adopted for alpha emitters was 10 15 Bq.y -1 for a single site, but limited to 10 14 Bq.y -1 for 226 Ra and supported 210 Po. In addition, to meet the requirements of the London Convention, a derived limit should be expressed in terms of concentration, which for alpha emitters was 10 10 Bq.t -1 , but limited to 10 14 Bq.t -1 for 226 Ra and supported 210 Po, assuming an upper limit to the mass dumping rate of 10 5 t per year at a single dumping site. New data on the radioactivity in the marine environment and biota, including plankton, indicated a potential alpha radiation dose to these aquatic organisms due to the release of technologically enhanced naturally occurring radioactive materials (TENORM) wastes. At the highest accumulation of 239 Pu in the zooplankton Gammarus in Thule, Greenland, due to an accidental release associated with military activities, the dose rate reached about 0.14 μGy.h -1 . Such dose rate was similar to that received by the phytoplankton Chaetoceros and Rhizosolenia from Agulhas current, Africa, due to naturally occurring radioactive materials (NORM) supposedly enhanced for almost one century of gold mining at first, and subsequently because of heap-leaching uranium extraction from the tailings left behind by earlier gold miners. The paper will discuss the alpha radiation dose to aquatic biota, in general, and to plankton, in particular, due to potential releases of TENORM wastes in the aquatic environment. (author)

  12. Cumulative radiation effect

    International Nuclear Information System (INIS)

    Kirk, J.; Gray, W.M.; Watson, E.R.

    1977-01-01

    In five previous papers, the concept of Cumulative Radiation Effect (CRE) has been presented as a scale of accumulative sub-tolerance radiation damage, with a unique value of the CRE describing a specific level of radiation effect. Simple nomographic and tabular methods for the solution of practical problems in radiotherapy are now described. An essential feature of solving a CRE problem is firstly to present it in a concise and readily appreciated form, and, to do this, nomenclature has been introduced to describe schedules and regimes as compactly as possible. Simple algebraic equations have been derived to describe the CRE achieved by multi-schedule regimes. In these equations, the equivalence conditions existing at the junctions between schedules are not explicit and the equations are based on the CREs of the constituent schedules assessed individually without reference to their context in the regime as a whole. This independent evaluation of CREs for each schedule has resulted in a considerable simplification in the calculation of complex problems. The calculations are further simplified by the use of suitable tables and nomograms, so that the mathematics involved is reduced to simple arithmetical operations which require at the most the use of a slide rule but can be done by hand. The order of procedure in the presentation and calculation of CRE problems can be summarised in an evaluation procedure sheet. The resulting simple methods for solving practical problems of any complexity on the CRE-system are demonstrated by a number of examples. (author)

  13. Radiation effects on microelectronics

    International Nuclear Information System (INIS)

    Gover, J.E.

    1987-01-01

    Applications of radiation-hardened microelectronics in nuclear power systems include (a) light water reactor (LWR) containment building, postaccident instrumentation that can operate through the beta and gamma radiation released in a design basis loss-of-coolant accident; (b) advanced LWR instrumentation and control systems employing distributed digital integrated circuit (IC) technology to achieve a high degree of artificial intelligence and thereby reduce the probability of operator error under accident conditions; (c) instrumentation, command, control and communication systems for space nuclear power applications that must operate during the neutron and gamma-ray core leakage environments as well as the background electron, proton, and heavy charged particle environments of space; and (d) robotics systems designed for the described functions. Advanced microelectronics offer advantages in cost and reliability over alternative approaches to instrumentation and control. No semiconductor technology is hard to all classes of radiation effects phenomena. As the effects have become better understood, however, significant progress has been made in hardening IC technology. Application of hardened microelectronics to nuclear power systems has lagged military applications because of the limited market potential of hardened instruments and numerous institutional impediments

  14. Radiation effect on implanted pacemakers

    International Nuclear Information System (INIS)

    Pourhamidi, A.H.

    1983-01-01

    It was previously thought that diagnostic or therapeutic ionizing radiation did not have an adverse effect on the function of cardiac pacemakers. Recently, however, some authors have reported damaging effect of therapeutic radiation on cardiac pulse generators. An analysis of a recently-extracted pacemaker documented the effect of radiation on the pacemaker pulse generator

  15. Radiation effects on polyethylenes

    International Nuclear Information System (INIS)

    Suzuki, T.; Oki, Y.; Numajiri, M.; Miura, T.; Kondo, K.; Tanabe, Y.; Ishiyama, M.; Ito, Y.

    1992-01-01

    Radiation effects on four kinds of polyethylenes were studied from the viewpoints of mechanical properties, free radicals and free volumes. The samples were irradiated using a cobalt 60 gamma source to give doses up to 3MGy. The degradation of mechanical strength due to gamma-irradiation was evaluated by the elongation at break and its tensile strength. Radiation induced free radicals were measured by ESR. Free volumes observed by the o-Ps component of the positron annihilation spectrum are normally the large ones located in the amorphous regions and after irradiation these are created in crystalline regions, too. The sizes and the relative numbers of free volumes were evaluated by lifetimes and intensities of a long-lived component of positronium, respectively. Using these data, the properties of polyethylenes before and after irradiation are discussed. (author)

  16. Energetic response of Chlorella vulgaris to alpha radiation and PCB stress

    International Nuclear Information System (INIS)

    Schaffer, S.A.

    1982-01-01

    This research project has evaluated the bioenergetic response of the green alga Chlorella vulgaris following acute exposure to either the physical stress of radiation or the chemical stress of PCBs. After exposure, changes in survival or growth, adenylate pools (ATP, ADP, and AMP), CO 2 fixation and oxygen evolution and uptake were measured. By employing anaerobic conditions, or the electron transport inhibitor DCMU or dark conditions separately and in specific combinations, this study evaluated the response of three separate algal ATP producing mechanisms (respiration, total and cyclic photophosphorylation) to alpha radiation or PCB. The use of the adenylate energy charge ratio as an indicator of stress was also evaluated. The results of the radiation experiments indicated that alpha particle exposure between 25 to 275 rads caused a one-hour latent demand for ATP due to radioinduced DNA repair. In order to compensate for this ATP demand, nonessential utilization of ATP was decreased by slowing the rate of carbon fixation. The results also suggest that use of radiation as a tool to study algal physiology. The data obtained from the PCB experiments again showed each phosphorylation mechanism to be insensitive to 10, 100 and 200 ppm Aroclor 1254 exposures. Data suggest, however, that PCBs caused an increased photosynthetic rate, and total adenylate pool with decreased growth. The use of the adenylate energy charge ratio as a stress indicator was assessed. Because this ratio did not fluctuate at doses of radiation or PCBs that caused reduced survival and growth rates, this study concluded that for Chlorella the adenylate energy charge ration was a poor indicator of sublethal stress

  17. V. Physical effects in ionizing radiation passage through matter

    International Nuclear Information System (INIS)

    1984-01-01

    The ionization of the medium during absorption of alpha particles is described. The ranges are given of alpha particles in the air and in certain liquids and solids. The absorption of protons and deuterons takes place similarly as in alpha particles but protons and deuterons have a bigger range at the same energy. The term half-thickness has been introduced for the absorption of beta particles. For different energies of beta particles the absorption of these particles is graphically represented for different materials. The greatest attention is devoted to the absorption of electromagnetic radiation, i.e., X radiation and gamma radiation. The mechanisms are explained of absorption by photoelectric effect, the Compton effect and electron pair formation. In X radiation radiotherapy, filters are used, mostly aluminium, copper or zinc plates. The values are given of radiation intensity for different thicknesses of aluminium and copper filters and a survey is given of combined filters for 220 to 400 kV. For radiotherapy purposes great attention is devoted to the calculation of the depth dose. The effects are discussed of ionizing radiation on photographic emulsion, on changes in the colouring of some substances and fluorescence. Also given are the biological effects of ionizing radiation and the theory of direct and indirect effects is briefly described. (E.S.)

  18. Biological effects of ionising radiation

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    The paper reports the proceedings of a conference organised jointly by Friends of the Earth (U.K.) and Greenpeace (International). The aim of the conference was to discuss the effects of low level radiation, particularly on man, within the terms of dose/risk relationships. The topics discussed included: sources of radiation, radiation discharges from nuclear establishments, predictive modelling of radiation hazards, radiation effects at Hiroshima, low dose effects and ICRP dose limits, variation in sensitivity to radiation, and the link between childhood cancer and nuclear power. (U.K.)

  19. Neurobehavioral teratogenic effects of clomipramine and alpha-methyldopa

    NARCIS (Netherlands)

    Mirmiran, M; Van Haaren, F; Louwerse, A; van de Poll, N E; de Boer, Sietse

    1989-01-01

    Neonatal treatment of rats with centrally acting drugs such as clomipramine was shown to affect adult body and brain weight, behavior and sleep. We made a further study of the effects of clomipramine and tested one dose of alpha-methyldopa. Male rats were treated twice daily with saline, 7.5 or 15

  20. The Effects of Curcumin on Alpha Amylase in Diabetics Rats

    Directory of Open Access Journals (Sweden)

    Mahmood Najafian

    2015-12-01

    Full Text Available Background One of the therapeutic approaches to lower postprandial blood glucose is to inhibition breakdown of starch by inhibiting carbohydrate hydrolysis enzymes. Alpha-amylase catalyzes the hydrolysis of α-(1, 4-D-glycosidic linkages of starch and other glucose polymers. Inhibitors of this enzyme could be used in the treatment of diabetes. Objectives Based on this purpose we examined the effect of curcumin on alpha amylase and its IC50 and Ki. Materials and Methods In this experimental study, 60 rats were divided into two major groups, normal and diabetic, and each was subsequently divided into five subgroups. One of them as control group that received grape seed oil and four of them as experimental groups that received curcumin at 10, 20, 40 and 80 mg/kg (each group include six rats. Blood glucose levels were measured every three days. Serum insulin levels were measured three times, in the first day, middle and end of the experimental period. The activity of serum alpha amylase was measured in the end of experimental period. Results The results showed that curcumin is a competitive inhibitor for alpha amylase with IC50 = 51.32 µM and Ki = 20.17 µM. In both diabetic and normal groups in all doses nearly dose dependent manner reduced blood glucose and insulin levels. In both diabetic and normal groups decreased levels of serum alpha amylase activity. Conclusions It may be concluded that curcumin is a potent inhibitor of alpha amylase and has beneficial effects in the treatment of overweight and diabetes

  1. Biological radiation effects

    International Nuclear Information System (INIS)

    Koggl, D.; Dedenkov, A.N.

    1986-01-01

    All nowadays problems of radio biology are considered: types of ionizing radiations, their interaction with material; damage of molecular structures and their reparation; reaction of cells and their recovery from radiation damage; reaction of the whole organism and its separate systems. Particular attention is given to the problems of radiation carcinogenesis and radiation hazard for man

  2. Cumulative radiation effect

    International Nuclear Information System (INIS)

    Kirk, J.; Cain, O.; Gray, W.M.

    1977-01-01

    Cumulative Radiation Effect (CRE) represents a scale of accumulative sub-tolerance radiation damage, with a unique value of the CRE describing a specific level of radiation effect. Computer calculations have been used to simplify the evaluation of problems associated with the applications of the CRE-system in radiotherapy. In a general appraisal of the applications of computers to the CRE-system, the various problems encountered in clinical radiotherapy have been categorised into those involving the evaluation of a CRE at a point in tissue and those involving the calculation of CRE distributions. As a general guide, the computer techniques adopted at the Glasgow Institute of Radiotherapeutics for the solution of CRE problems are presented, and consist basically of a package of three interactive programs for point CRE calculations and a Fortran program which calculates CRE distributions for iso-effect treatment planning. Many examples are given to demonstrate the applications of these programs, and special emphasis has been laid on the problem of treating a point in tissue with different doses per fraction on alternate treatment days. The wide range of possible clinical applications of the CRE-system has been outlined and described under the categories of routine clinical applications, retrospective and prospective surveys of patient treatment, and experimental and theoretical research. Some of these applications such as the results of surveys and studies of time optimisation of treatment schedules could have far-reaching consequences and lead to significant improvements in treatment and cure rates with the minimum damage to normal tissue. (author)

  3. Effect of Photon Hormesis on Dose Responses to Alpha Particles in Zebrafish Embryos

    Directory of Open Access Journals (Sweden)

    Candy Yuen Ping Ng

    2017-02-01

    Full Text Available Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio as the in vivo vertebrate model. The toxicity of these ionizing radiations in the zebrafish embryos was assessed using the apoptotic counts at 20, 24, or 30 h post fertilization (hpf revealed through acridine orange (AO staining. For alpha-particle doses ≥ 4.4 mGy, the additional X-ray dose of 10 mGy significantly reduced the number of apoptotic cells at 24 hpf, which proved the presence of photon hormesis. Smaller alpha-particle doses might not have inflicted sufficient aggregate damages to trigger photon hormesis. The time gap T between the X-ray (10 mGy and alpha-particle (4.4 mGy exposures was also studied. Photon hormesis was present when T ≤ 30 min, but was absent when T = 60 min, at which time repair of damage induced by alpha particles would have completed to prevent their interactions with those induced by X-rays. Finally, the drop in the apoptotic counts at 24 hpf due to photon hormesis was explained by bringing the apoptotic events earlier to 20 hpf, which strongly supported the removal of aberrant cells through apoptosis as an underlying mechanism for photon hormesis.

  4. Effects of background radiation

    International Nuclear Information System (INIS)

    Knox, E.G.; Stewart, A.M.; Gilman, E.A.; Kneale, G.W.

    1987-01-01

    The primary objective of this investigation is to measure the relationship between exposure to different levels of background gamma radiation in different parts of the country, and different Relative Risks for leukaemias and cancers in children. The investigation is linked to an earlier analysis of the effects of prenatal medical x-rays upon leukaemia and cancer risk; the prior hypothesis on which the background-study was based, is derived from the earlier results. In a third analysis, the authors attempted to measure varying potency of medical x-rays delivered at different stages of gestation and the results supply a link between the other two estimates. (author)

  5. Radiation effects on vasoproliferation

    International Nuclear Information System (INIS)

    Yamaura, Hirotsugu; Matsuzawa, Taiju

    1975-01-01

    The authors quantitatively examined radiation effects on vascular proliferarion, using the rat transparent chamber technique to observe the living microcirculation. We studied the process of vasoproliferation and revascularization from the surrounding pre-existing vessels into the surgically avascularized area in the chamber, by measuring the vascular lenght photographically. A hyper-vascularized zone, about 0.5 mm in with, was formed on the vascularizing frontier, the significance of which is so far not known. When the chambers were irradiated with various doses of 60 Co γ-rays, a dose dependent inhibition of vasoproliferation was observed. (auth.)

  6. Radiation effects on vasoproliferation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaura, H; Matsuzawa, T [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer

    1975-06-01

    The authors quantitatively examined radiation effects on vascular proliferarion, using the rat transparent chamber technique to observe the living microcirculation. We studied the process of vasoproliferation and revascularization from the surrounding pre-existing vessels into the surgically avascularized area in the chamber, by measuring the vascular lenght photographically. A hyper-vascularized zone, about 0.5 mm in with, was formed on the vascularizing frontier, the significance of which is so far not known. When the chambers were irradiated with various doses of /sup 60/Co ..gamma..-rays, a dose dependent inhibition of vasoproliferation was observed.

  7. Resonance-enhanced two-photon ionization of ions by Lyman alpha radiation in gaseous nebulae.

    Science.gov (United States)

    Johansson, S; Letokhov, V

    2001-01-26

    One of the mysteries of nebulae in the vicinity of bright stars is the appearance of bright emission spectral lines of ions, which imply fairly high excitation temperatures. We suggest that an ion formation mechanism, based on resonance-enhanced two-photon ionization (RETPI) by intense H Lyman alpha radiation (wavelength of 1215 angstroms) trapped inside optically thick nebulae, can produce these spectral lines. The rate of such an ionization process is high enough for rarefied gaseous media where the recombination rate of the ions formed can be 10(-6) to 10(-8) per second for an electron density of 10(3) to 10(5) per cubic centimeter in the nebula. Under such conditions, the photo-ions formed may subsequently undergo further RETPI, catalyzed by intense He i and He ii radiation, which also gets enhanced in optically thick nebulae that contain enough helium.

  8. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1986-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 references, 3 figures, 2 tables

  9. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1985-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as μ-randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, 1/2d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 refs., 3 figs., 2 tabs

  10. Biological Effects of Individual Alpha Particles

    International Nuclear Information System (INIS)

    L. A. Braby; R. R. Ford

    2002-01-01

    In order to provide quantitative data on the mechanisms of intercellular communication leading to bystander effects in irradiated cell populations, a positive ion microbeam irradiation system was set up at Texas A and M University and the rate at which photobleached and active fluorescent molecules are exchanged between irradiated and unirradiated cells was studied. AG1522 human fibroblast cells were chosen as one of the lines in this study because they had been shown to be proficient at bystander effects, and because they exhibited scrape loading response and lindane inhibition of effects which suggest that gap junction communication was involved. Surprisingly, detailed measurements of recovery from photobleaching suggested that gap junction communication did not occur in these cells. More detailed studies with gap junction inhibitors and with immunohistochemistry assays for gap junctions seem to confirm that these cells do not communicate in this way. A cell line which does communicate by gap junctions, Clone 9, shows no change in communication rates before and after irradiation. Other techniques, such as assessment of nuclear cross section were developed to determine if bystander effects alter cell progression through the cell cycle and the growth of individual cells

  11. Biological radiation effects

    International Nuclear Information System (INIS)

    Sejourne, Michele.

    1977-01-01

    This work examines ionizing radiations: what they are, where they come from, their actions and consequences, finally the norms and preventive measures necessary to avoid serious contamination, whether the individual or the population in general is involved. Man has always been exposed to natural irradiation, but owing to the growing use of ionizing radiations both in medicine and in industry, not to mention nuclear tests and their use as an argument of dissuasion, the irradiation of human beings is increasing daily. Radioactive contamination does remain latent, apart from acute cases, but this is where the danger lies since the consequences may not appear until long after the irradiation. Of all biological effects due to the action of radioelements the genetic risk is one of the most important, affecting the entire population and especially the generations to come. The risk of cancer and leukemia induction plays a substantial part also since a large number of people may be concerned, depending on the mode of contamination involved. All these long-term dangers do not of course exclude the various general or local effects to which the individual alone may be exposed and which sometimes constitute a threat to life. As a result the use of ionizing radiations must be limited and should only be involved if no other process can serve instead. The regulations governing radioelements must be stringent and their application strictly supervised for the better protection of man. This protection must be not only individual but also collective since pollution exists in air, water and land passes to plants and animals and finally reaches the last link in the food chain, man [fr

  12. Radiation effects and radiation risks. 2. ed.

    International Nuclear Information System (INIS)

    Lengfelder, E.; Forst, D.; Feist, H.; Pratzel, H.G.

    1990-01-01

    The book presents the facts and the principles of assessment and evaluation of biological radiation effects in general and also with particular reference to the reactor accident of Chernobyl, reviewing the consequences and the environmental situation on the basis of current national and international literature, including research work by the authors. The material compiled in this book is intended especially for physicians, but will also prove useful for persons working in the public health services, in administration, or other services taking care of people. The authors tried to find an easily comprehensible way of presenting and explaining the very complex processes and mechanisms of biological radiation effects and carcinogenesis, displaying the physical primary processes and the mechanisms of the molecular radiation effects up to the effects of low-level radiation, and present results of comparative epidemiologic studies. This section has been given considerable space, in proportion to its significance. It also contains literature references for further reading, offering more insight and knowledge of aspects of special subject fields. The authors also present less known results and data and discuss them against the background of well-known research results and approaches. Apart from the purpose of presenting comprehensive information, the authors intend to give an impact for further thinking about the problems, and helpful tools for independent decisions and action on the basis of improved insight and assessment, and in this context particularly point to the problems induced by the Chernobyl reactor accident. (orig.) With 10 maps in appendix [de

  13. Effects of radiation

    International Nuclear Information System (INIS)

    Masse, R.

    2006-01-01

    The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

  14. Alpha self irradiation effects in nuclear borosilicate glass

    International Nuclear Information System (INIS)

    Peuget, S.; Roudil, D.; Deschanels, X.; Jegou, C.; Broudic, V.; Bart, J.M.

    2004-01-01

    The properties of actinide glasses are studied in the context of high-level waste management programs. Reprocessing high burnup fuels in particular will increase the minor actinide content in the glass package, resulting in higher cumulative alpha decay doses in the glass, and raising the question of the glass matrix behavior and especially its containment properties. The effect of alpha self-irradiation on the glass behavior is evaluated by doping the glass with a short-lived actinide ( 244 Cm) to reach in several years the alpha dose received by the future glass packages over several thousand years. 'R7T7' borosilicate glasses were doped with 3 different curium contents (0.04, 0.4 and 1.2 wt% 244 CmO 2 ). The density and mechanical properties of the curium-doped glasses were characterized up to 2. 10 18 α/g, revealing only a slight evolution of the macroscopic behavior of R7T7 glass in this range. The leaching behavior of curium-doped glass was also studied by Soxhlet tests. The results do not show any significant evolution of the initial alteration rate with the alpha dose. (authors)

  15. Effect of alpha irradiation on UO2 surface reactivity in aqueous media

    International Nuclear Information System (INIS)

    Jegou, C.; Muzeau, B.; Broudic, V.; Poulesquen, A.; Roudil, D.; Jorion, F.; Corbel, C.

    2005-01-01

    The option of direct disposal of spent nuclear fuel in a deep geological formation raises the need to investigate the long-term behavior of the UO 2 matrix in aqueous media subjected to α-β-γ radiation. The β-γ emitters account for most of the activity of spent fuel at the moment it is removed from the reactor, but diminish within a millennial time frame by over three orders of magnitude to less than the long-term activity. The latter persists over much longer time periods and must therefore be taken into account over a geological disposal time scale. Leaching experiments with solution renewal were carried out on UO 2 pellets doped with alpha emitters ( 238 Pu and 239 Pu) to quantify the impact of alpha irradiation on UO 2 matrix alteration. Three batches of doped UO 2 pellets with different alpha flux levels (3.30 x 10 4 , 3.30 x 10 5 , and 3.2 x 10 6 α cm -2 s -1 ) were studied. The results obtained in aerated and deaerated media immediately after sample annealing or interim storage in air provide a better understanding of the UO 2 matrix alteration mechanisms under alpha irradiation. Interim storage in air of UO 2 pellets doped with alpha emitters results in variations of the UO 2 surface reactivity, which depends on the alpha particle flux at the interface and on the interim storage duration. The variation in the surface reactivity and the greater uranium release following interim storage cannot be attributed to the effect of alpha radiolysis in aerated media since the uranium release tends toward the same value after several leaching cycles for the doped UO 2 pellet batches and spent fuel. Oxygen diffusion enhanced by alpha irradiation of the extreme surface layer and/or radiolysis of the air could account for the oxidation of the surface UO 2 to UO 2+x . However, leaching experiments performed in deaerated media after annealing the samples and preleaching the surface suggest that alpha radiolysis does indeed affect the dissolution, which varies with the

  16. Radiation effects on living systems

    International Nuclear Information System (INIS)

    Hawley, N.J.

    1984-04-01

    This bibliography includes papers and reports by Atomic Energy of Canada Limited scientists concerning radiation effects on living systems. It is divided into three sections: Radiobiology, Radiation Biochemistry and Radiation Chemistry. It is intended that the bibliography will be updated regularly

  17. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1977-03-01

    A summary is given of studies on radiation effects in light-emitting diodes, laser diodes, detectors, optical isolators and optical fibers. It is shown that the study of radiation damage in these devices can provide valuable information concerning the nature of the devices themselves, as well as methods of hardening these devices for applications in radiation environments

  18. Genetic effects of ionising radiation

    International Nuclear Information System (INIS)

    Saunders, P.A.H.

    1991-12-01

    Ionizing radiation effects on the gem cells, which can result in genetic abnormalities, are described. The basic mechanisms of radiation interactions with chromosomes, or specifically DNA, which can result in radiation induced mutation are discussed. Methods of estimating genetic risks, and some values for quantitative risk estimates are given. (U.K.). 13 refs., 2 figs., 1 tab

  19. Biological effects of particle radiation

    International Nuclear Information System (INIS)

    Sakamoto, Kiyohiko

    1988-01-01

    Conventional radiations such as photons, gamma rays or electrons show several physical or biological disadvantages to bring tumors to cure, therefore, more and more attentions is being paid to new modalitie such as fast neutrons, protons, negative pions and heavy ions, which are expected to overcome some of the defects of the conventional radiations. Except for fast neutrons, these particle radiations show excellet physical dose localization in tissue, moreover, in terms of biological effects, they demonstrate several features compared to conventional radiations, namely low oxygen enhancement ratio, high value of relative biological effectiveness, smaller cellular recovery, larger therapeutic gain factor and less cell cycle dependency in radiation sensitivity. In present paper the biological effects of particle radiations are shown comparing to the effects of conventional radiations. (author)

  20. Terrestrial radiation effects in ULSI devices and electronic systems

    CERN Document Server

    Ibe, Eishi H

    2014-01-01

    A practical guide on how mathematical approaches can be used to analyze and control radiation effects in semiconductor devices within various environments Covers faults in ULSI devices to failures in electronic systems caused by a wide variety of radiation fields, including electrons, alpha -rays, muons, gamma rays, neutrons and heavy ions. Readers will learn the environmental radiation features at the ground or avionics altitude. Readers will also learn how to make numerical models from physical insight and what kind of mathematical approaches should be implemented to analyze the radiation effects. A wide variety of mitigation techniques against soft-errors are reviewed and discussed. The author shows how to model sophisticated radiation effects in condensed matter in order to quantify and control them. The book provides the reader with the knowledge on a wide variety of radiation fields and their effects on the electronic devices and systems. It explains how electronic systems including servers and rout...

  1. Biology of ionizing radiation effects

    International Nuclear Information System (INIS)

    Ferradini, C.; Pucheault, J.

    1983-01-01

    The present trends in biology of ionizing radiation are reviewed. The following topics are investigated: interaction of ionizing radiations with matter; the radiolysis of water and aqueous solutions; properties of the free radicals intervening in the couples O 2 /H 2 O and H 2 O/H 2 ; radiation chemistry of biological compounds; biological effects of ionizing radiations; biochemical mechanisms involving free radicals as intermediates; applications (biotechnological applications, origins of life) [fr

  2. The biological effects of radiation

    International Nuclear Information System (INIS)

    Sykes, D.A.

    1979-01-01

    The hazards of radiations to man are briefly covered in this paper. The natural background sources of radiations are stated and their resulting doses are compared to those received voluntarily by man. The basis of how radiations cause biological damage is given and the resulting somatic effects are shown for varying magnitude of dose. Risk estimates are given for cancer induction and genetic effects are briefly discussed. Finally four case studies of radiation damage to humans are examined exemplifying the symptoms of large doses of radiations [af

  3. Radiation effects on lymphocytes

    International Nuclear Information System (INIS)

    Roser, B.

    1976-01-01

    This review of the ontogeny of lymphocyte populations concentrates on sites of production, rates of production, and the factors governing the differentiation and longevity of the various lymphocyte pools. The physiology of the lymphocyte pools is described with particular emphasis on recirculation from blood to lymph through lymphoid tissues. The separate routes of recirculation of both thymus-derived and nonthymus-derived lymphocytes and the possible anatomical sites and mechanisms of lymphocyte cooperation are discussed. Radiation effects on lymphocyte populations are divided into two sections. First, the effects of whole-body irradiation on the total lymphocyte pools are discussed including the differential effects of irradiation on T lymphocytes, B lymphocytes, lymphoblasts, and plasma cells. The differential sensitivity of various types of immune response is correlated, where possible, with the differential sensitivity of the lymphocyte types involved. Second, experimental attempts to selectively deplete discrete subpopulations of the total lymphocyte pools, e.g., recirculating cells, are briefly discussed with particular emphasis on studies on the effects of the localization of radionuclides in lymphoid tissue

  4. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Experiments with small animals, tissue cultures, and inanimate materials help with understanding the effects of ionizing radiation that occur at the molecular level and cause the gross effects observed in man. Topics covered in this chapter include the following: Radiolysis of Water; Radiolysis of Organic Compounds; Radiolysis in Cells; Radiation Exposure and Dose Units; Dose Response Curves; Radiation Effects in Animals; Factors Affecting Health Risks. 8 refs., 3 figs., 5 tabs

  5. On surface clustering and Pauli principle effects in alpha decay

    International Nuclear Information System (INIS)

    Holan, S.

    1983-01-01

    The importance of the correct description of nuclear surface region in alpha decay calculations is pointed out. A model is proposed takinq into account explicitly surface clustering and Pauli principle effects which are essential in this region. A method for solving the main integrodifferential equation of the model by using the oscillator shell basis and the Collatz method is worked out. The first numerical results are obtained for nonlocal potential of the atpha particle-daughter nucleus interaction

  6. Metabolism and biological effects of alpha-emitting radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Bair, W. J.

    1979-05-01

    The emphasis of much of the current and planned research on the toxicity of alpha-emitting radionuclides is directed toward the complexities of actual and potential conditions of occupational environmental exposures of human beings. These, as well as the more limited studies on mechanisms of biological transport and effects, should increase our ability to predict health risks more accurately and to deal more confidently with human exposures, if and when they occur.

  7. Effects of radiation on man

    International Nuclear Information System (INIS)

    Saunders, P.A.H.

    1981-01-01

    The available evidence on the effects of radiation on man and the predictions that have been made of possible low level effects are reviewed. Data from United Nations Scientific Committee of the Effects of Atomic Radiation (UNSCEAR) and the committee on the Biological Effects of Ionising Radiation (BEIR) is used to illustrate the acute, delayed and hereditary effects of high dose levels. The effects of low dose levels are discussed on the assumption that both somatic and hereditary effects can be predicted on the basis of linear extrapolation from high dose effects. (U.K.)

  8. Alpha-tocopherol succinate- and AMD3100-mobilized progenitors mitigate radiation combined injury in mice

    International Nuclear Information System (INIS)

    Singh, Vijay K.; Wise, Stephen Y.; Fatanmi, Oluseyi O.; Beattie, Lindsay A.; Ducey, Elizabeth J.; Seed, Thomas M.

    2014-01-01

    The purpose of this study was to elucidate the role of alpha-tocopherol succinate (TS)- and AMD3100-mobilized progenitors in mitigating combined injury associated with acute radiation exposure in combination with secondary physical wounding. CD2F1 mice were exposed to high doses of cobalt-60 gamma-radiation and then transfused intravenously with 5 million peripheral blood mononuclear cells (PBMCs) from TS- and AMD3100-injected mice after irradiation. Within 1 h after irradiation, mice were exposed to secondary wounding. Mice were observed for 30 d after irradiation and cytokine analysis was conducted by multiplex Luminex assay at various time-points after irradiation and wounding. Our results initially demonstrated that transfusion of TS-mobilized progenitors from normal mice enhanced survival of acutely irradiated mice exposed 24 h prior to transfusion to supralethal doses (11.5–12.5 Gy) of 60 Co gamma-radiation. Subsequently, comparable transfusions of TS-mobilized progenitors were shown to significantly mitigate severe combined injuries in acutely irradiated mice. TS administered 24 h before irradiation was able to protect mice against combined injury as well. Cytokine results demonstrated that wounding modulates irradiation-induced cytokines. This study further supports the conclusion that the infusion of TS-mobilized progenitor-containing PBMCs acts as a bridging therapy in radiation-combined-injury mice. We suggest that this novel bridging therapeutic approach involving the infusion of TS-mobilized hematopoietic progenitors following acute radiation exposure or combined injury might be applicable to humans. (author)

  9. A critical review of radiation effects on borosilicate glasses

    International Nuclear Information System (INIS)

    Lanza, F.; Manara, A.; Rutten, F. van

    1981-01-01

    Most of the experimental values have been obtained by loading the glass with alpha emitters like Cm 244 and Pu 238. The data existing in literature on stored energy, and density variation are presented and discussed. Attention is given to the variation of the leaching rate due to the radiation effect. Samples loaded with alpha emitters have given data up to 0.17 dpa and such bombarded with heavy ions show large effects due to dose rate effects. A study on defect formation has shown that under electrons irradiation, formation of bubbles is possible. (DG)

  10. Chemical effects of radiation

    International Nuclear Information System (INIS)

    Philips, G.O.

    1986-01-01

    Ionizing radiations initiate chemical changes in materials because of the high energy of their quanta. In water, highly reactive free radicals are produced which can initiate secondary changes of solutes, and in chemical of biological molecules in contact with the water. Free radicals can also be directly produced in irradiated medical products. Their fate can be identified and the molecular basis of radiation inactivation clarified. Methods have now been developed to protect and minimise such radiation damage. (author)

  11. Radiation dosimetry of iodine-123 HEAT, an alpha-1 receptor imaging agent

    International Nuclear Information System (INIS)

    Thomas, K.D.; Greer, D.M.; Couch, M.W.; Williams, C.M.

    1987-01-01

    Biologic distribution data in the rat were obtained for the alpha-1 adrenoceptor imaging agent (+/-) 2-[beta-(iodo-4-hydroxyphenyl)ethylaminomethyl]tetralone (HEAT) labeled with [ 123 I]. The major excretory routes were through the liver (67%) and the kidney (33%). Internal radiation absorbed dose estimates to nine source organs, total body, the GI tract, gonads, and red bone marrow were calculated for the human using the physical decay data for [ 123 I]. The critical organ was found to be the lower large intestine, receiving 1.1 rad per mCi of [ 123 I]HEAT administered. The total-body dose was found to be 58 mrad per mCi

  12. Monitoring of gross alpha in the air and exposure gamma radiation on and around the coal fire power at Paiton

    International Nuclear Information System (INIS)

    Sutarman; Warsono, Asep

    1998-01-01

    Coal is burned in furnace operating at up to 1,700 o C in order to produce electrical energy and ash (bottom ash and fly-ash). The fly-ash is released to the atmosphere or environment around the coal fire power. Therefore, the environmental radioactivity monitoring should be carried out for gross alpha in the air and exposure gamma radiation. The measurement of gross alpha have been carried out using the alpha scintillation counter with the ZnS(Ag) detector, and measurement of gamma radiation using the high pressure ion chamber. The results obtained showed that the gross alpha in the air were the ranging from (7.1 ± 1,2) mBq m -3 to (12.2 ± 1.9) mBq m -3 and the exposure gamma radiation were (3.69 ± 0.11) μR/h to (9.55 ± 0.15) μR/h. The data were still lower than the limit of the maximum permissible concentration and annual intake for breathing but the gross alpha data were higher than in the nuclear installations. (authors)

  13. Targeted alpha therapy using Radium-223: From physics to biological effects.

    Science.gov (United States)

    Marques, I A; Neves, A R; Abrantes, A M; Pires, A S; Tavares-da-Silva, E; Figueiredo, A; Botelho, M F

    2018-05-25

    With the advance of the use of ionizing radiation in therapy, targeted alpha therapy (TAT) has assumed an important role around the world. This kind of therapy can potentially reduce side effects caused by radiation in normal tissues and increased destructive radiobiological effects in tumor cells. However, in many countries, the use of this therapy is still in a pioneering phase. Radium-223 ( 223 Ra), an alpha-emitting radionuclide, has been the first of its kind to be approved for the treatment of bone metastasis in metastatic castration-resistant prostate cancer. Nevertheless, the interaction mechanism and the direct effects of this radiopharmaceutical in tumor cells are not fully understood neither characterized at a molecular level. In fact, the ways how TAT is linked to radiobiological effects in cancer is not yet revised. Therefore, this review introduces some physical properties of TAT that leads to biological effects and links this information to the hallmarks of cancer. The authors also collected the studies developed with 223 Ra to correlate with the three categories reviewed - properties of TAT, 5 R's of radiobiology and hallmarks of cancer- and with the promising future to this radiopharmaceutical. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Neurophysiological appropriateness of ionizing radiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Nyagu, A I; Loganovsky, K N [Department of Neurology, Inst. of Clinical Radiology, Scientific Centre for Radiation Medicine of Academy of Medical Sciences of Ukraine, Kiev (Ukraine)

    1997-11-01

    The goal of this study was to compare bioelectrical activity of the brain in remote period of acute radiation sickness (ARS), chronic and prenatal irradiation as a result of the Chernobyl disaster. Registration of computerized 19-channel EEG, visual and somato-sensory evoked potentials have been carried out for 70 patients who had a verified ARS, 100 Chernobyl disaster survivors, who have been working in the Chernobyl exclusion zone since 1986-87 during 5 and more years, 50 prenatally irradiated children, and relevant controls. The relative risks of neurophysiological abnormalities are 4.5 for the ARS-patients, 3.6 for the chronically irradiated persons and 3.7 for the prenatally irradiated children. The data obtained testify to possibility of radiation-induced neurophysiological abnormalities in examined Chernobyl accident survivors which seems to be non-stochastic effects of ionizing radiation. For all examined irradiated patients it was typically an increasing of {delta}- and {beta}- powers of EEG, particularly, in the frontal lobe shifted to the left fronto-temporal region, but spectral power of both {theta}- and {alpha}-range was significantly depressed. Aforesaid signs together with data of evoked potentials reflect the structural and functional abnormalities of limbic system and the left hemisphere as the first revealed neurophysiological appropriateness of ionizing radiation effects. (author). 25 refs.

  15. SU-C-303-02: Correlating Metabolic Response to Radiation Therapy with HIF-1alpha Expression

    International Nuclear Information System (INIS)

    Campos, D; Peeters, W; Nickel, K; Eliceiri, K; Kimple, R; Van Der Kogel, A; Kissick, M

    2015-01-01

    Purpose: To understand radiation induced alterations in cellular metabolism which could be used to assess treatment or normal tissue response to aid in patient-specific adaptive radiotherapy. This work aims to compare the metabolic response of two head and neck cell lines, one malignant (UM-SCC-22B) and one benign (Normal Oral Keratinocyte), to ionizing radiation. Responses are compared to alterations in HIF-1alpha expression. These dynamics can potentially serve as biomarkers in assessing treatment response allowing for patient-specific adaptive radiotherapy. Methods: Measurements of metabolism and HIF-1alpha expression were taken before and X minutes after a 10 Gy dose of radiation delivered via an orthovoltage x-ray source. In vitro changes in metabolic activity were measured via fluorescence lifetime imaging (FLIM) to assess the mean lifetime of NADH autofluorescence following a dose of 10 Gy. HIF-1alpha expression was measured via immunohistochemical staining of in vitro treated cells and expression was quantified using the FIJI software package. Results: FLIM demonstrated a decrease in the mean fluorescence lifetime of NADH by 100 ps following 10 Gy indicating a shift towards glycolytic pathways for malignant cells; whereas this benign cell line showed little change in metabolic signature. Immunohistochemical analysis showed significant changes in HIF-1alpha expression in response to 10 Gy of radiation that correlate to metabolic profiles. Conclusion: Radiation induces significant changes in metabolic activity and HIF-1alpha expression. These alterations occur on time scales approximating the duration of common radiation treatments (approximately tens of minutes). Further understanding these dynamics has important implications with regard to improvement of therapy and biomarkers of treatment response

  16. SU-C-303-02: Correlating Metabolic Response to Radiation Therapy with HIF-1alpha Expression

    Energy Technology Data Exchange (ETDEWEB)

    Campos, D [University of Wisconsin Madison, Madison, WI (United States); Peeters, W [Radboud University Medical Center, Nijmegen, GA (United States); Nickel, K [University of Wisconsin, Madison, WI (United States); Eliceiri, K; Kimple, R; Van Der Kogel, A; Kissick, M [University of Wisconsin, Madison, Wisconsin (United States)

    2015-06-15

    Purpose: To understand radiation induced alterations in cellular metabolism which could be used to assess treatment or normal tissue response to aid in patient-specific adaptive radiotherapy. This work aims to compare the metabolic response of two head and neck cell lines, one malignant (UM-SCC-22B) and one benign (Normal Oral Keratinocyte), to ionizing radiation. Responses are compared to alterations in HIF-1alpha expression. These dynamics can potentially serve as biomarkers in assessing treatment response allowing for patient-specific adaptive radiotherapy. Methods: Measurements of metabolism and HIF-1alpha expression were taken before and X minutes after a 10 Gy dose of radiation delivered via an orthovoltage x-ray source. In vitro changes in metabolic activity were measured via fluorescence lifetime imaging (FLIM) to assess the mean lifetime of NADH autofluorescence following a dose of 10 Gy. HIF-1alpha expression was measured via immunohistochemical staining of in vitro treated cells and expression was quantified using the FIJI software package. Results: FLIM demonstrated a decrease in the mean fluorescence lifetime of NADH by 100 ps following 10 Gy indicating a shift towards glycolytic pathways for malignant cells; whereas this benign cell line showed little change in metabolic signature. Immunohistochemical analysis showed significant changes in HIF-1alpha expression in response to 10 Gy of radiation that correlate to metabolic profiles. Conclusion: Radiation induces significant changes in metabolic activity and HIF-1alpha expression. These alterations occur on time scales approximating the duration of common radiation treatments (approximately tens of minutes). Further understanding these dynamics has important implications with regard to improvement of therapy and biomarkers of treatment response.

  17. Response of tumour necrosis factor alpha (TNF ) in blood and spleen mice that vaccinated with P.berghei radiation

    International Nuclear Information System (INIS)

    Darlina; Tur R; Teja K

    2015-01-01

    Tumor necrosis factor is a glycoprotein derived from helper T lymphocytes that play an important role in the body's response against malaria infection. However, TNF-α has double play that is on appropriate levels will provide protection and healing, while at excessive levels which may be a response to hyperparasitemia. Thus investigated the expression of TNF alpha secreted blood lymphocytes and spleen cells the mice that's infected with 1 x 10 7 P.berghei infectious or inactivated by radiation. Levels of TNF alpha serum and spleen cell culture medium was monitored on days 2, 7, 14 post infection. Monitoring of parasite growth every two days for 60 days. Determination of TNF alpha levels were measure using ELISA. The results showed parasitaemia mice infected with 175 Gy irradiated parasites have pre patent period of 16 days longer than the control (non-irradiated parasites) with low parasitaemia. TNF alpha concentration that secreted spleen cells of mice vaccinated higher than control mice. Concentration of TNF alpha that secreted blood lymphocyte of mice vaccinated lower than control mice. It was concluded that the secretion of TNF alpha by blood lymphocytes caused more pathogenic factors of the parasite, while the secretion of TNF alpha in spleen due to an immune response against the parasite. (author)

  18. Study of alpha-tocopherol as a protector of damages induced to the skin by ionizing radiation

    International Nuclear Information System (INIS)

    Lucero, M.J.; Vigo, J.; Leon, M.J.; Sanchez, J.A.; Martin, F.

    1997-01-01

    An experimental study was carried out in animals for determining the characteristics of alpha-tocopherol protection against lesions caused by free radicals produced by ionizing radiation. Two different concentrations of alpha-tocopherol were applied on the same exposed sample. A linear electron accelerator of 6 MeV was used for the production of free radicals and a dose of 2800 cGy. The lesions were submitted to clinical studies for anatomic pathologies. The conclusion of this study is that alpha-tocopherol applied to skin before and immediately after the exposure to ionizing radiation has the capability to protect it, developing a perfectly differentiated epidermis and of greater thickness than normally considered

  19. Computer modelling of radiation-induced bystander effect

    International Nuclear Information System (INIS)

    Khvostunov, Igor K.; Nikjoo, Hooshang

    2002-01-01

    Radiation-induced genomic instability and bystander effects are now well established consequences of exposure of living cells to ionising radiation. It has been observed that cells not directly hit by radiation tracks may still exhibit radiation effects. We present a quantitative modelling of the radiation-induced bystander effect based on a diffusion model of spreading the bystander signal. The model assumes the bystander factor to be a protein of low molecular weight, given out by the hit cell, diffusing in the medium and reacting with non-hit cells. The model calculations successfully predict the results of cell survival in an irradiated conditioned medium. The model predicts the shape of dose-effect relationship for cell survival and oncogenic transformation induced by broad-beam and micro-beam irradiation by alpha-particles. (author)

  20. Diffusion effects in undulator radiation

    Directory of Open Access Journals (Sweden)

    Ilya Agapov

    2014-11-01

    Full Text Available Quantum diffusion effects in undulator radiation in semiclassical approximation are considered. Short-term effects on the electron beam motion are discussed and it is shown that approaches based on diffusion approximation with drift-diffusion coefficients derived from undulator or bending magnet radiation spectrum, and on Poisson statistics with radiation spectrum defined by the local beding field, all lead to similar results in terms of electron energy spread for cases of practical interest. An analytical estimate of the influence of quantum diffusion on the undulator radiation spectrum is derived.

  1. Measurements of the light conversion efficiency of lithium borate for alpha particles relative to cobalt-60 gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, D.T.; Wall, B.F.; Fisher, E.S. (National Radiological Protection Board, Harwell (UK))

    1982-01-01

    The results are reported of measurements of the light conversion efficiencies of lithium borate TLD phosphor of British Nuclear Fuels Ltd. manufacture to 5.65 MeV and 2.4 MeV alpha particles relative to /sup 60/Co gamma radiation.

  2. Generation of continuous coherent radiation at Lyman-alpha and 1S-2P Spectroscopy of atomic hydrogen

    NARCIS (Netherlands)

    Pahl, A.; Fendel, P.; Henrich, B.R.; Walz, J.; Hansch, T.W.; Eikema, K.S.E.

    2005-01-01

    Continuous coherent radiation from wavelengths from 121 to 123 nm in the vacuum ultraviolet (VUV) was generated by four-wave sum-frequency mixing in mercury vapor. A yield of 20 nW at Lyman-alpha (121.57 nm) was achieved. We describe the experimental setup in detail and present a calculation of the

  3. Temperature Dependency and Alpha Response of Semi-Insulating GaAs Schottky Radiation Detector at Low Bias Voltage

    International Nuclear Information System (INIS)

    Kang, Sang Mook; Ha, Jang Ho; Park, Se Hwan; Kim, Han Soo; Kim, Yong Kyun

    2009-01-01

    The last decade has seen a growing interest in semiconductor radiation detectors operated at room or nearly room temperature. Great efforts have been invested in the development of radiation detectors based on semi-insulating (SI) GaAs. The main reasons are as follows: (i) high resistance against radiation damage; (ii) it possesses a good energy resolution, which relates to its active volume; (iii) such a detector also exhibits fast signal rise times, which results from a high mobility and drift velocity of charge carriers; (iv) its large band gap energy allows a SI GaAs detector to operate at room temperature. Other important features are a good technology base and low production and operating costs. An alpha particle monitoring method for the detection of Pu-238 and U-235 is becoming important in homeland security. Alpha measurement in a vacuum is known to provide a good resolution sufficient to separate an isotope abundance in nuclear materials. However, in order to apply it to a high radiation field like a spent fuel treatment facility, a nuclear material loading and unloading process in a vacuum is one of the great disadvantages. Therefore, the main technical issue is to develop a detector for alpha detection at air condition and low power operation for integration type device. In this study we fabricated GaAs Schottky detector by using semi-insulating (SI) wafer and measured current-voltage characteristic curve and alpha response with 5.5 MeV Am-241 source

  4. Radiation and biophysical studies on cells and viruses. Progress report, April 1, 1976--June 30, 1977. [Gamma radiation, alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Cole, A.

    1977-01-01

    Progress is reported on the following research projects: genetic structure of DNA, chromosomes, and nucleoproteins; particle beam studies of radiosensitive sites; division delay in CHO cells induced by partly penetrating alpha particles; location of cellular sites for mutation induction; sites for radioinduced cell transformation using partly penetrating particle beams; gamma-ray and particle irradiation of nucleoproteins and other model systems; quantitation of surface antigens on normal and neoplastic cells by x-ray fluorescence; hyperthermic effects on cell survival and DNA repair mechanisms; and studies on radioinduced cell transformation. (HLW)

  5. Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos

    International Nuclear Information System (INIS)

    Ng, C.Y.P.; Cheng, S.H.; Yu, K.N.

    2017-01-01

    In the present work, we studied the effects of low-dose X-ray photons on the alpha-particle induced bystander effects between embryos of the zebrafish, Danio rerio. The effects on the naive whole embryos were studied through quantification of apoptotic signals (amounts of cells undergoing apoptosis) at 24 h post fertilization (hpf) using vital dye acridine orange staining, followed by counting the stained cells under a fluorescent microscope. We report data showing that embryos at 5 hpf subjected to a 4.4 mGy alpha-particle irradiation could release a stress signal into the medium, which could induce bystander effect in partnered naive embryos sharing the same medium. We also report that the bystander effect was deactivated when the irradiated embryos were subjected to a concomitant irradiation of 10 or 14 mGy of X-rays, but no such deactivation was achieved if the concomitant X-ray dose dropped to 2.5 or 5 mGy. In the present study, the significant drop in the amount of apoptotic signals on the embryos having received 4.4 mGy alpha particles together X-rays irradiation from 2.5 or 5 mGy to 10 or 14 mGy, together with the deactivation of RIBE with concomitant irradiation of 10 or 14 mGy of X-rays supported the participation of photon hormesis with an onset dose between 5 and 10 mGy, which might lead to removal of aberrant cells through early apoptosis or induction of high-fidelity DNA repair. As we found that photons and alpha particles could have opposite biological effects when these were simultaneously irradiated onto living organisms, these ionizing radiations could be viewed as two different environmental stressors, and the resultant effects could be regarded as multiple stressor effects. The present work presented the first study on a multiple stressor effect which occurred on bystander organisms. In other words, this was a non-targeted multiple stressor effect. The photon hormesis could also explain some failed attempts to observe neutron-induced bystander

  6. Radiation effect on polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Deng Pengyang; Zhong Xiaoguang; Sun Jiazhen

    1999-01-01

    Polytetrafluoroethylene (PTFE) has always been regarded as a typical kind of radiation degradation polymer. But, in fact, PTFE can be induced crosslinking by γ-ray or electron beam at some special conditions (free oxygen and a narrow temperature region at 335 +- 5 degree C). Compared with radiation degradiation PTFE, cosslinking PTFE owns a lot of new properties. Some articles concerning with these have been published, which will be systematically reviewed in this

  7. Radiation effects on cell membranes

    International Nuclear Information System (INIS)

    Koeteles, G.J.

    1982-01-01

    Experimental data are presented concerning the effects of relatively low doses of x radiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the manifold influence of radiation-induced membrane phenomenon on the development and regeneration of radiation injuries. (author)

  8. Radiation effects in optoelectronic devices

    International Nuclear Information System (INIS)

    Barnes, C.E.; Wiczer, J.J.

    1984-05-01

    Purpose of this report is to provide not only a summary of radiation damage studies at Sandia National Laboratories, but also of those in the literature on the components of optoelectronic systems: light emitting diodes (LEDs), laser diodes, photodetectors, optical fibers, and optical isolators. This review of radiation damage in optoelectronic components is structured according to device type. In each section, a brief discussion of those device properties relevant to radiation effects is given

  9. The effects of cosmic radiation on implantable medical devices

    International Nuclear Information System (INIS)

    Bradley, P.

    1996-01-01

    Metal oxide semiconductor (MOS) integrated circuits, with the benefits of low power consumption, represent the state of the art technology for implantable medical devices. Three significant sources of radiation are classified as having the ability to damage or alter the behavior of implantable electronics; Secondary neutron cosmic radiation, alpha particle radiation from the device packaging and therapeutic doses(up to 70 Gγ) of high energy radiation used in radiation oncology. The effects of alpha particle radiation from the packaging may be eliminated by the use of polyimide or silicone rubber die coatings. The relatively low incidence of therapeutic radiation incident on an implantable device and the use of die coating leaves cosmic radiation induced secondary neutron single event upset (SEU) as the main pervasive ionising radiation threat to the reliability of implantable devices. A theoretical model which predicts the susceptibility of a RAM cell to secondary neutron cosmic radiation induced SEU is presented. The model correlates well within the statistical uncertainty associated with both the theoretical and field estimate. The predicted Soft Error Rate (SER) is 4.8 x l0 -12 upsets/(bit hr) compared to an observed upset rate of 8.5 x 10 -12 upsets/(bit hr) from 20 upsets collected over a total of 284672 device days. The predicted upset rate may increase by up to 20% when consideration is given to patients flying in aircraft The upset rate is also consistent with the expected geographical variations of the secondary cosmic ray neutron flux, although insufficient upsets precluded a statistically significant test. This is the first clinical data set obtained indicating the effects of cosmic radiation on implantable devices. Importantly, it may be used to predict the susceptibility of future to the implantable device designs to the effects of cosmic radiation

  10. Dosimetric characterization of BeO samples in alpha, beta and X radiation beams using luminescent techniques

    International Nuclear Information System (INIS)

    Groppo, Daniela Piai

    2013-01-01

    In the medical field, the ionizing radiation is used both for therapeutic and diagnostic purposes, in a wide range of radiation doses. In order to ensure that the objective is achieved in practice, detailed studies of detectors and devices in different types of radiations beams are necessary. In this work a dosimetric characterization of BeO samples was performed using the techniques of thermoluminescence (TL) and optically stimulated luminescence (OSL) by a comparison of their response for alpha, beta and X radiations and the establishment of an appropriated system for use in monitoring of these radiations beams. The main results are: the high sensitivity to beta radiation for both techniques, good reproducibility of TL and OSL response (coefficients of variation lower than 5%), maximum energy dependence of the X radiation of 28% for the TL technique, and only 7% for the OSL technique, within the studied energy range. The dosimetric characteristics obtained in this work show the possibility of applying BeO samples to dosimetry of alpha, beta and X radiations, considering the studied dose ranges, using the TL and OSL techniques. From the results obtained, the samples of BeO showed their potential use for beam dosimetry in diagnostic radiology and radiotherapy. (author)

  11. Szilard-Chalmers effect in natural. cap alpha. disintegrations

    Energy Technology Data Exchange (ETDEWEB)

    Haissinsky, M; Cottin, M

    1948-11-01

    The Szilard-Chalmers effect resulting from the reaction UI(/sup 238/U) ..-->.. UX1(/sup 234/Th) was investigated. The authors developed a chemical method adapted from a technique of Starke (Naturwissenschaften 30, 577(1942)) to separate UX1 which was formed by ..cap alpha.. emission. The experimental accuracy is insufficient to indicate the influence of the degree of dilution of the chemical solutions used on the efficiency of separation, but it is shown that there is a marked decrease in efficiency when solid compounds are used, which is consistent with a hypothesis of Franck and Rabinowitsch (Trans. Faraday Soc. 30, 120(1934)).

  12. Effects of radiation; Effets des radiations

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

  13. Effects of radiation; Effets des radiations

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R. [Office de Protection contre les Rayonnements Ionisants, 78 - le Vesinet (France)

    2006-07-01

    The medical consequences of a whole-body irradiation come from the destruction of cells and inflammatory reactions it provokes. The most sensitive organs are the tissues that actively split. The embryo is particularly sensitive, from 200 mSv for the effects on the brain development. The reproduction functions are reached for man from 2000 mSv, the ovary sensitivity is less, the oocytes do not split after the fetus life. For adult the bone marrow outrage leads to the disappearing of blood cells (4000 mSv). The doses from 6000 to 10000 mSv lead the failure of the digestive system and lung. for the upper doses every tissue is reached, particularly by the effects on cells of blood vessels. Important brain dysfunctions appear beyond 10000 mSv. As regards the delayed effects of overexposures the epidemiology brings to light sanitary consequences of the exposure of the population to the ionizing radiations and requires that all the possible factors associated for that purpose are considered. About hereditary effects, it appears that moderate acute radiation exposures of even a relatively large human population must have little impact, in spite of the rate of spontaneous congenital deformations is of the order of 6 %. For the induction of cancers, it is not observed excess for doses lower than 200 mSv for adults and 100 mSv for children (the populations studied are survival people of hiroshima and Nagasaki, patients treated by irradiation, uranium miners, children exposed to radioactive iodine after Chernobylsk accident). To simplify an expression of the risk has been fixed to 5% of induced cancer by Sv for population and 4% by Sv for workers, the different being explained by the demography and the sensitivity of the youngest age groups. As regards the low doses of radiations, a bundle of convergent epidemiological observations notices the absence of effects of the low doses rates. Biological mechanisms, notably of repair are approached, then certain accidents (Goiania

  14. Ionizing radiations: effects and sources

    International Nuclear Information System (INIS)

    Vignes, S.; Nenot, J.C.

    1978-01-01

    Having first mentioned the effects of ionizing radiations in cancerogenisis, pre-natal, and genetic fields, the authors present the different sources of radiations and estimate their respective contributions to the total irradiation dose. Their paper makes reference to the main elements of a report issued by the United Nations Scientific Committee in 1977 [fr

  15. Genetic effects of ionising radiation

    International Nuclear Information System (INIS)

    Saunders, P.

    1981-01-01

    The mutagenic effects of ionising radiation on germ cells with resulting genetic abnormalities in subsequent generations, are considered. Having examined a simple model to explain the interaction of ionising radiation with genetic material and discussed its limitations, the methods whereby mutations are transmitted are discussed. Methods of estimating genetic risks and the results of such studies are examined. (U.K.)

  16. Calculation of the Electronic Parameters of an Al/DNA/p-Si Schottky Barrier Diode Influenced by Alpha Radiation

    Directory of Open Access Journals (Sweden)

    Hassan Maktuff Jaber Al-Ta'ii

    2015-02-01

    Full Text Available Many types of materials such as inorganic semiconductors have been employed as detectors for nuclear radiation, the importance of which has increased significantly due to recent nuclear catastrophes. Despite the many advantages of this type of materials, the ability to measure direct cellular or biological responses to radiation might improve detector sensitivity. In this context, semiconducting organic materials such as deoxyribonucleic acid or DNA have been studied in recent years. This was established by studying the varying electronic properties of DNA-metal or semiconductor junctions when exposed to radiation. In this work, we investigated the electronics of aluminium (Al/DNA/silicon (Si rectifying junctions using their current-voltage (I-V characteristics when exposed to alpha radiation. Diode parameters such as ideality factor, barrier height and series resistance were determined for different irradiation times. The observed results show significant changes with exposure time or total dosage received. An increased deviation from ideal diode conditions (7.2 to 18.0 was observed when they were bombarded with alpha particles for up to 40 min. Using the conventional technique, barrier height values were observed to generally increase after 2, 6, 10, 20 and 30 min of radiation. The same trend was seen in the values of the series resistance (0.5889–1.423 Ω for 2–8 min. These changes in the electronic properties of the DNA/Si junctions could therefore be utilized in the construction of sensitive alpha particle detectors.

  17. Effect of alpha linolenic acid supplementation on serum prostate specific antigen (PSA): results from the alpha omega trial

    NARCIS (Netherlands)

    Brouwer, Ingeborg A.; Geleijnse, Johanna M.; Klaasen, Veronique M.; Smit, Liesbeth A.; Giltay, Erik J.; de Goede, Janette; Heijboer, Annemieke C.; Kromhout, Daan; Katan, Martijn B.

    2013-01-01

    Alpha linolenic acid (ALA) is the major omega-3 fatty acid in the diet. Evidence on health effects of ALA is not conclusive, but some observational studies found an increased risk of prostate cancer with higher intake of ALA. We examined the effect of ALA supplementation on serum concentrations of

  18. Utility of Normal Tissue-to-Tumor {alpha}/{beta} Ratio When Evaluating Isodoses of Isoeffective Radiation Therapy Treatment Plans

    Energy Technology Data Exchange (ETDEWEB)

    Gay, Hiram A., E-mail: hgay@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States); Jin Jianyue [Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan (United States); Chang, Albert J. [Department of Radiation Oncology, University of California, San Francisco, California (United States); Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2013-01-01

    Purpose: To achieve a better understanding of the effect of the number of fractions on normal tissue sparing for equivalent tumor control in radiation therapy plans by using equivalent biologically effective dose (BED) isoeffect calculations. Methods and Materials: The simple linear quadratic (LQ) model was assumed to be valid up to 10 Gy per fraction. Using the model, we formulated a well-known mathematical equality for the tumor prescription dose and probed and solved a second mathematical problem for normal tissue isoeffect. That is, for a given arbitrary relative isodose distribution (treatment plan in percentages), 2 isoeffective tumor treatment regimens (N fractions of the dose D and n fractions of the dose d) were denoted, which resulted in the same BED (corresponding to 100% prescription isodose). Given these situations, the LQ model was further exploited to mathematically establish a unique relative isodose level, z (%), for the same arbitrary treatment plan, where the BED to normal tissues was also isoeffective for both fractionation regimens. Results: For the previously stated problem, the relative isodose level z (%), where the BEDs to the normal tissue were also equal, was defined by the normal tissue {alpha}/{beta} ratio divided by the tumor {alpha}/{beta} times 100%. Fewer fractions offers a therapeutic advantage for those portions of the normal tissue located outside the isodose surface, z, whereas more fractions offer a therapeutic advantage for those portions of the normal tissue within the isodose surface, z. Conclusions: Relative isodose-based treatment plan evaluations may be useful for comparing isoeffective tumor regimens in terms of normal tissue effects. Regions of tissues that would benefit from hypofractionation or standard fractionation can be identified.

  19. Epigenetic effects of ionizing radiation

    International Nuclear Information System (INIS)

    EI-Naggar, A.M.

    2007-01-01

    Data generated during the last three decades provide evidence of Epigenetic Effects that ave-induced by ionizing radiation, particularly those of high LET values, and low level dose exposures. Epigenesist is defined as the stepwise process by which genetic information, as modified by environmental influences, is translated into the substance and behavior of cells, tissues, organism.The epigenetic effects cited in the literature are essentially classified into fine types depending on the type and nature of the effect induced.The most accepted postulation, for the occurrence of these epigenetic effects, is a radiation induced bio electric disturbances in the environment of the non-irradiated cellular volume. This will trigger signals that will induce effects in the unirradiated cells.The epigenetic effects referenced in the literature up to date are five types; namely, Genomic Instability, Bystander. Effects, Clastogenic Plasma Factors,, Abscopal Effects, and Tran generational Effects.The demonstration of Epigenetic Effects associated with exposure to ionizing radiation indicates the need to re- examine the concept of radiation dose and target size. Also an improved understanding of qualifiring and quantifying radiation risk estimates may be attained. Also, a more logical means to understand the underlying mechanisms of radiation induced carcinogenic transformation of cells

  20. Genomic Profiling of a Human Leukemic Monocytic Cell-Line (THP-1 Exposed to Alpha Particle Radiation

    Directory of Open Access Journals (Sweden)

    Vinita Chauhan

    2012-01-01

    Full Text Available This study examined alpha (α- particle radiation effects on global changes in gene expression in human leukemic monocytic cells (THP-1 for the purposes of mining for candidate biomarkers that could be used for the development of a biological assessment tool. THP-1 cells were exposed to α-particle radiation at a dose range of 0 to 1.5 Gy. Twenty-four hours and three days after exposure gene expression was monitored using microarray technology. A total of 16 genes were dose responsive and classified as early onset due to their expression 24 h after exposure. Forty-eight transcripts were dose responsive and classified as late-onset as they were expressed 72 h after exposure. Among these genes, 6 genes were time and dose responsive and validated further using alternate technology. These transcripts were upregulated and associated with biological processes related to immune function, organelle stability and cell signalling/communication. This panel of genes merits further validation to determine if they are strong candidate biomarkers indicative of α-particle exposure.

  1. Radiation hazards and biological effects of ionising radiation on man

    International Nuclear Information System (INIS)

    Siti Najila Mohd Janib

    2004-01-01

    The contents of this chapter are follows - Mechanism of damage: direct action of radiation, indirect action of radiation. Classification of effects: somatic effect, induction of cancer, factors, affecting somatic effects, genetic effect, inherited abnormalities, induced effects, early effects, late effects, deterministic effect, stochastic effect. Effect of specific group: development abnormality, childhood Cancer, fertile women, risk and uncertainty, comparison of risk

  2. Radiation and radiation effects; Strahlung und Strahlenwirkung

    Energy Technology Data Exchange (ETDEWEB)

    Neumaier, S. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). Arbeitsgruppe Strahlenschutz; Janssen, H. [Physikalisch-Technische Bundesanstalt, Berlin (Germany). Abt. Ionisierende Strahlung

    2006-12-15

    The average dose incurred by the German population is about 4 millisievert p.a., about half of which results from natural radiation sources. The second half is caused nearly completely by medical applications. Only a very small fraction of the annual dose results from technical applications. This special issue of PTB focuses on the measuring problems relating to natural radiation sources and technical applications of ionizing radiation. The current contribution also outlines some important aspects of radiation exposure from medical applications. (orig.)

  3. Two-stream cyclotron radiative instabilities due to the marginally mirror-trapped fraction for fustion alphas in tokamaks

    International Nuclear Information System (INIS)

    Arunasalam, V.

    1995-07-01

    It is shown here that the marginally mirror-trapped fraction of the newly-born fusion alpha particles in the deuterium-tritium (DT) reaction dominated tokamak plasmas can induce a two-stream cyclotron radiative instability for the fast Alfven waves propagating near the harmonics of the alpha particle cyclotron frequency ω cα . This can explain both the experimentally observed time behavior and the spatially localized origin of the fusion product ion cyclotron emission (ICE) in TFTR at frequencies ω ∼ mω cα

  4. Radiobiological Effects of Alpha-Particles from Astatine-211: From DNA Damage to Cell Death

    Energy Technology Data Exchange (ETDEWEB)

    Claesson, Kristina

    2011-05-15

    In recent years, the use of high linear energy transfer (LET) radiation for radiotherapeutic applications has gained increased interest. Astatine-211 (211At) is an alpha-particle emitting radionuclide, promising for targeted radioimmunotherapy of isolated tumor cells and microscopic clusters. To improve development of safe radiotherapy using 211At it is important to increase our knowledge of the radiobiological effects in cells. During radiotherapy, both tumors and adjacent normal tissue will be irradiated and therefore, it is of importance to understand differences in the radio response between proliferating and resting cells. The aim of this thesis was to investigate effects in fibroblasts with different proliferation status after irradiation with alpha-particles from 211At or X-rays, from inflicted DNA damage, to cellular responses and biological consequences. Throughout this work, irradiation was performed with alpha-particles from 211A or X-rays. The induction and repair of double-strand breaks (DSBs) in human normal fibroblasts were investigated using pulsed-field gel electrophoresis and fragment analysis. The relative biological effectiveness (RBE) of 211At for DSB induction varied between 1.4 and 3.1. A small increase of DSBs was observed in cycling cells compared to stationary cells. The repair kinetics was slower after 211At and more residual damage was found after 24 h. Comparison between cells with different proliferation status showed that the repair was inefficient in cycling cells with more residual damage, regardless of radiation quality. Activation of cell cycle arrests was investigated using immunofluorescent labeling of the checkpoint kinase Chk2 and by measuring cell cycle distributions with flow cytometry analysis. After alpha-particle irradiation, the average number of Chk2-foci was larger and the cells had a more affected cell cycle progression for several weeks compared with X-irradiated cells, indicating a more powerful arrest after 211At

  5. Effect of cetuximab in combination with alpha-radioimmunotherapy in cultured squamous cell carcinomas

    Energy Technology Data Exchange (ETDEWEB)

    Nestor, Marika, E-mail: marika.nestor@bms.uu.s [Unit of Otolaryngology and Head and Neck Surgery, Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala (Sweden); Unit of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Uppsala University, S-751 85 Uppsala (Sweden); Sundstroem, Magnus [Unit of Molecular Pathology, Department of Genetics and Pathology, Uppsala University (Sweden); Anniko, Matti [Unit of Otolaryngology and Head and Neck Surgery, Department of Surgical Sciences, Uppsala University, S-751 85 Uppsala (Sweden); Tolmachev, Vladimir [Unit of Biomedical Radiation Sciences, Department of Oncology, Radiology and Clinical Immunology, Uppsala University, S-751 85 Uppsala (Sweden)

    2011-01-15

    Aim: The monoclonal antibody cetuximab, targeting the epidermal growth factor receptor (EGFR), is a promising molecular targeting agent to be used in combination with radiation for anticancer therapy. In this study, effects of cetuximab in combination with alpha-emitting radioimmunotherapy (RIT) in a panel of cultured human squamous cell carcinomas (SCCs) were assessed. Methods: SCC cell lines were characterized and treated with cetuximab in combination with anti-CD44v6 RIT using the astatinated chimeric monoclonal antibody U36 ({sup 211}At-cMAb U36). Effects on {sup 211}At-cMAb U36 uptake, internalization and cell proliferation were then assessed in SCC cells. Results: Cetuximab in combination with {sup 211}At-cMAb U36 mediated increased growth inhibition compared to RIT or cetuximab alone in two cell lines. However, cetuximab also mediated radioprotective effects compared to RIT alone in two cell lines. The radioprotective effects occurred in the cell lines in which cetuximab clearly inhibited cell growth during radiation exposure. Cetuximab treatment also influenced {sup 211}At-cMAb-U36 uptake and internalization, suggesting interactions between CD44v6 and EGFR. Conclusions: Results from this study demonstrate the vast importance of further clarifying the mechanisms of cetuximab and radiation response, and the relationship between EGFR and suitable RIT targets. This is important not only in order to avoid potential radioprotective effects, but also in order to find and utilize potential synergistic effects from these combinations.

  6. Effect of cetuximab in combination with alpha-radioimmunotherapy in cultured squamous cell carcinomas

    International Nuclear Information System (INIS)

    Nestor, Marika; Sundstroem, Magnus; Anniko, Matti; Tolmachev, Vladimir

    2011-01-01

    Aim: The monoclonal antibody cetuximab, targeting the epidermal growth factor receptor (EGFR), is a promising molecular targeting agent to be used in combination with radiation for anticancer therapy. In this study, effects of cetuximab in combination with alpha-emitting radioimmunotherapy (RIT) in a panel of cultured human squamous cell carcinomas (SCCs) were assessed. Methods: SCC cell lines were characterized and treated with cetuximab in combination with anti-CD44v6 RIT using the astatinated chimeric monoclonal antibody U36 ( 211 At-cMAb U36). Effects on 211 At-cMAb U36 uptake, internalization and cell proliferation were then assessed in SCC cells. Results: Cetuximab in combination with 211 At-cMAb U36 mediated increased growth inhibition compared to RIT or cetuximab alone in two cell lines. However, cetuximab also mediated radioprotective effects compared to RIT alone in two cell lines. The radioprotective effects occurred in the cell lines in which cetuximab clearly inhibited cell growth during radiation exposure. Cetuximab treatment also influenced 211 At-cMAb-U36 uptake and internalization, suggesting interactions between CD44v6 and EGFR. Conclusions: Results from this study demonstrate the vast importance of further clarifying the mechanisms of cetuximab and radiation response, and the relationship between EGFR and suitable RIT targets. This is important not only in order to avoid potential radioprotective effects, but also in order to find and utilize potential synergistic effects from these combinations.

  7. Radiation Effects in Nuclear Waste Materials

    International Nuclear Information System (INIS)

    Weber, William J.

    2005-01-01

    The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials. This work provides the underpinning science to develop improved glass and ceramic waste forms for the immobilization and disposition of high-level tank waste, excess plutonium, plutonium residues and scrap, other actinides, and other nuclear waste streams. Furthermore, this work is developing develop predictive models for the performance of nuclear waste forms and stabilized nuclear materials. Thus, the research performed under this project has significant implications for the immobilization of High-Level Waste (HLW) and Nuclear Materials, two mission areas within the Office of Environmental Management (EM). With regard to the HLW mission, this research will lead to improved understanding of radiation-induced degradation mechanisms and their effects on dissolution kinetics, as well as development of predictive models for waste form performance. In the Nuclear Materials mission, this research will lead to improvements in the understanding of radiation effects on the chemical and structural properties of materials for the stabilization and long-term storage of plutonium, highly-enriched uranium, and other actinides. The research uses plutonium incorporation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of alpha decay and beta decay on relevant glasses and ceramics. The research under this project has the potential to result in improved glass and ceramic materials for the stabilization and immobilization of high-level tank waste, plutonium residues and scraps, surplus weapons plutonium, highly-enriched uranium, other actinides, and other radioactive materials

  8. Radiation Effects in Nuclear Waste Materials

    International Nuclear Information System (INIS)

    Weber, William J.; Wang, Lumin; Hess, Nancy J.; Icenhower, Jonathan P.; Thevuthasan, Suntharampillai

    2003-01-01

    The objective of this project is to develop a fundamental understanding of radiation effects in glasses and ceramics, as well as the influence of solid-state radiation effects on aqueous dissolution kinetics, which may impact the performance of nuclear waste forms and stabilized nuclear materials. This work provides the underpinning science to develop improved glass and ceramic waste forms for the immobilization and disposition of high-level tank waste, excess plutonium, plutonium residues and scrap, other actinides, and other nuclear waste streams. Furthermore, this work is developing develop predictive models for the performance of nuclear waste forms and stabilized nuclear materials. Thus, the research performed under this project has significant implications for the immobilization of High-Level Waste (HLW) and Nuclear Materials, two mission areas within the Office of Environmental Management (EM). With regard to the HLW mission, this research will lead to improved understanding of radiation-induced degradation mechanisms and their effects on dissolution kinetics, as well as development of predictive models for waste form performance. In the Nuclear Materials mission, this research will lead to improvements in the understanding of radiation effects on the chemical and structural properties of materials for the stabilization and long-term storage of plutonium, highly-enriched uranium, and other actinides. The research uses plutonium incorporation, ion-beam irradiation, and electron-beam irradiation to simulate the effects of alpha decay and beta decay on relevant glasses and ceramics. The research under this project has the potential to result in improved glass and ceramic materials for the stabilization and immobilization of high-level tank waste, plutonium residues and scraps, surplus weapons plutonium, highly-enriched uranium, other actinides, and other radioactive materials

  9. Probability of bystander effect induced by alpha-particles emitted by radon progeny using the analytical model of tracheobronchial tree

    International Nuclear Information System (INIS)

    Jovanovic, B.; Nikezic, D.

    2010-01-01

    Radiation-induced biological bystander effects have become a phenomenon associated with the interaction of radiation with cells. There is a need to include the influence of biological effects in the dosimetry of the human lung. With this aim, the purpose of this work is to calculate the probability of bystander effect induced by alpha-particle radiation on sensitive cells of the human lung. Probability was calculated by applying the analytical model cylinder bifurcation, which was created to simulate the geometry of the human lung with the geometric distribution of cell nuclei in the airway wall of the tracheobronchial tree. This analytical model of the human tracheobronchial tree represents the extension of the ICRP 66 model, and follows it as much as possible. Reported probabilities are calculated for various targets and alpha-particle energies. Probability of bystander effect has been calculated for alpha particles with 6 and 7.69 MeV energies, which are emitted in the 222 Rn chain. The application of these results may enhance current dose risk estimation approaches in the sense of the inclusion of the influence of the biological effects. (authors)

  10. Radiation effects on structural materials

    International Nuclear Information System (INIS)

    Ghoniem, N.M.

    1991-01-01

    This report discusses the following topics on the effect radiation has on thermonuclear reactor materials: Atomic Displacements; Microstructure Evolution; Materials Engineering, Mechanics, and Design; Research on Low-Activation Steels; and Research Motivated by Grant Support

  11. Biological effects of ionizing radiation

    International Nuclear Information System (INIS)

    Gisone, Pablo; Perez, Maria R.

    2001-01-01

    It has been emphasised the importance of DNA as the main target for ionizing radiation, that can induce damage by its direct action on this molecule or by an indirect effect mediated by free-radicals generated by water radiolysis. Biological effects of ionizing radiation are influenced not only by the dose but also by the dose-rate and the radiation quality. Radiation induced damage, mainly DNA single and double strand breaks, is detected by molecular sensors which in turn trigger signalling cascades leading to cell cycle arrest to allow DNA repair or programmed cell death (apoptosis). Those effects related with cell death, named deterministic, exhibits a dose-threshold below which they are not observed. Acute radiation syndrome and radiological burns are examples of this kind of effects. Other radiation induced effects, called stochastic, are the consequence of cell transformation and do not exhibit a dose-threshold. This is the case of cancer induction and hereditary effects. The aim of this presentation is briefly describe the main aspects of deterministic and stochastic effects from the point of view of radiobiology and radio pathology. (author)

  12. Effects after prenatal radiation exposures

    International Nuclear Information System (INIS)

    Streffer, C.

    2001-01-01

    The mammalian organism is highly radiosensitive during all prenatal developmental periods. For most effects a dose relationship with a threshold is observed. These threshold doses are generally above the exposures from medical diagnostic procedures. The quality and extent of radiation effects are very much dependent on the developmental stage during which an exposure takes place and on the radiation dose. An exposure during the preimplantation period will cause lethality. Malformations are usually induced after exposures during the major organogenesis. Growth retardation is also possible during the late organogenesis and foetal periods. The lower limits of threshold doses for these effects are in the range of 100 mGy. A radiation exposure during the early foetal period can lead to severe mental retardation and impairment of intelligence. There are very serious effects with radiation doses above 0.3 Gy. Carcinogenesis can apparently occur after radiation exposures during the total prenatal development period. The radiation risk factor up to now has not been clear, but it seems that it is in the range of risk factors for cancer that are observed after exposures during childhood. For radiation doses that are used in radiological diagnostics the risk is zero or very low. A termination of pregnancy after doses below 100 mGy should not be considered. (author)

  13. Effects of radiation on erythropoiesis

    Energy Technology Data Exchange (ETDEWEB)

    Harriss, E B

    1971-04-01

    Since the pioneer work of Heineke (1903; 1905) many workers have studied the effect of radiation on haemopoiesis. Their work has been reviewed by Bloom (1948), by Jacobson (1954) and more recently by Bond et al. (1965). The subject continues to stimulate much interest but is now more concerned with the effects of radiation on the multipotential stem cell pool than on radiation damage to the erythropoietic cells themselves. Death from haemopoietic failure following an LD{sub 50/30} dose of radiation is probably not attributable to failure of erythropoiesis; while damage to the erythropoietic system certainly plays a part in the syndrome, it is not a major factor contributing to the death of the animal. Although the severity and time course of the response vary with the species studied, the general effects of radiation on erythropoiesis are similar in all mammalian bone marrow studied to date. Likewise, though the severity of the reaction varies somewhat with the energy of the radiation and has been used to compare the relative biological effectiveness of different types of radiation (Sinclair et al., 1962; Sztanyik, 1967), the response is different only in degree and not in its fundamental pattern. The initial syndrome of depression and recovery will therefore be described largely by reference to work performed on the response of the rat to single acute exposures of either whole-body or partial-body irradiation with conventional X-rays.

  14. Aerosol effects in radiation transfer

    International Nuclear Information System (INIS)

    Binenko, V.I.; Harshvardhan, H.

    1993-01-01

    The radiative properties and effects of aerosols are assessed for the following aerosol sources: relatively clean background aerosol, dust storms and dust outbreaks, anthropogenic pollution, and polluted cloud layers. Studies show it is the submicron aerosol fraction that plays a dominant radiative role in the atmosphere. The radiative effect of the aerosol depends not only on its loading but also on the underlying surface albedo and on solar zenith angle. It is only with highly reflecting surfaces such as Arctic ice that aerosols have a warming effect. Radiometric, microphysical, mineral composition, and refractive index measurements are presented for dust and in particular for the Saharan aerosol layer (SAL). Short-wave radiative heating of the atmosphere is caused by the SAL and is due mainly to absorption. However, the SAL does not contribute significantly to the long-wave thermal radiation budget. Field program studies of the radiative effects of aerosols are described. Anthropogenic aerosols deplete the incoming solar radiation. A case field study for a regional Ukrainian center is discussed. The urban aerosol causes a cooling of metropolitan centers, compared with outlying areas, during the day, which is followed by a warming trend at night. In another study, an increase in turbidity by a factor of 3 due to increased industrialization for Mexico City is noted, together with a drop in atmospheric transmission by 10% over a 50-year period. Numerous studies are cited that demonstrate that anthropogenic aerosols affect both the microphysical and radiative properties of clouds, which in turn affect regional climate. Particles acting as cloud nuclei are considered to have the greatest indirect effect on cloud absorptivity of short-wave radiation. Satellite observations show that low-level stratus clouds contaminated by ship exhaust at sea lead to an increase in cloud albedo

  15. Specific outcomes of the research on the radiation stability of the French nuclear glass towards alpha decay accumulation

    Science.gov (United States)

    Peuget, S.; Delaye, J.-M.; Jégou, C.

    2014-01-01

    This paper presents an overview of the main results of the French research on the long-term behavior of SON68 nuclear glass towards alpha decay accumulation. The effect of the radiation damage induced by alpha decay and also helium build-up were investigated by examining glass specimens, doped with a short-lived actinide 244Cm, irradiated by light and heavy ions. Additionally, atomistic simulations by molecular dynamics have provided further information on the atomic-scale effects of the macroscopic phenomena observed. These studies have shown that some macroscopic properties vary with the accumulation of alpha decay, but then stabilize after integrated doses of the order of 4 × 1018 α g-1. For example, the glass density diminishes by about 0.6%, its Young's modulus by about 15%, and its hardness by about 30%, while its fracture toughness increases by around 50%. The SEM and TEM characterization showed that the glass is still homogeneous. No phase separation, crystallization or bubbles formation was noticed up to an alpha decay dose corresponding to several thousand years of disposal of nuclear glass canister. Moreover the initial alteration rate of the glass is not significantly affected by the glass damage induced by alpha decays or heavy ions irradiations. The comparison of the macroscopic evolutions of the Cm doped glass with those obtained for glasses irradiated with light or heavy ions (from either experimental and molecular dynamic studies) suggests that the macroscopic evolutions are induced by the nuclear interactions induced by the recoil nuclei of alpha decay. The analysis of the behavior of the glass structure subjected to ballistic effects with various spectroscopic studies, together with the results of atomistic modeling by molecular dynamics, have identified some slight changes in the local order around some cations. Moreover a modification of the medium-range order has also been demonstrated through changes in the bond angles between network

  16. Specific outcomes of the research on the radiation stability of the French nuclear glass towards alpha decay accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Peuget, S., E-mail: sylvain.peuget@cea.fr; Delaye, J.-M.; Jégou, C.

    2014-01-15

    This paper presents an overview of the main results of the French research on the long-term behavior of SON68 nuclear glass towards alpha decay accumulation. The effect of the radiation damage induced by alpha decay and also helium build-up were investigated by examining glass specimens, doped with a short-lived actinide {sup 244}Cm, irradiated by light and heavy ions. Additionally, atomistic simulations by molecular dynamics have provided further information on the atomic-scale effects of the macroscopic phenomena observed. These studies have shown that some macroscopic properties vary with the accumulation of alpha decay, but then stabilize after integrated doses of the order of 4 × 10{sup 18} α g{sup −1}. For example, the glass density diminishes by about 0.6%, its Young’s modulus by about 15%, and its hardness by about 30%, while its fracture toughness increases by around 50%. The SEM and TEM characterization showed that the glass is still homogeneous. No phase separation, crystallization or bubbles formation was noticed up to an alpha decay dose corresponding to several thousand years of disposal of nuclear glass canister. Moreover the initial alteration rate of the glass is not significantly affected by the glass damage induced by alpha decays or heavy ions irradiations. The comparison of the macroscopic evolutions of the Cm doped glass with those obtained for glasses irradiated with light or heavy ions (from either experimental and molecular dynamic studies) suggests that the macroscopic evolutions are induced by the nuclear interactions induced by the recoil nuclei of alpha decay. The analysis of the behavior of the glass structure subjected to ballistic effects with various spectroscopic studies, together with the results of atomistic modeling by molecular dynamics, have identified some slight changes in the local order around some cations. Moreover a modification of the medium-range order has also been demonstrated through changes in the bond angles

  17. Low level radiation: biological effects

    International Nuclear Information System (INIS)

    Loken, M.K.

    1983-01-01

    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. Inferences as to the possible biological effects of low level radiation are generally based on extrapolations from those effects observed and measured following acute exposures to considerably higher doses of radiation. Thus, in order to shed light on the question of the possible biological effects of low level radiation, a wide variety of studies have been carried out using cells in culture and various species of plant and animal life. This manuscript makes reference to some of those studies with indications as to how and why the studies were done and the conclusions that might be drawn there from. In addition reference is made to the handling of this information by scientists, by environmentalists, and by the news media. Unfortunately, in many instances the public has been misled by what has been said and/or written. It is hoped that this presentation will provide an understandable and reasonable perspective on the various appropriate uses of radiation in our lives and how such uses do provide significant improvement in our health and in our quality of life

  18. On-line gross alpha radiation monitoring of natural waters with extractive scintillating resins

    International Nuclear Information System (INIS)

    Hughes, Lara; De Vol, T.A.

    2003-01-01

    Extractive scintillating resins, which are used to simultaneously separate and quantify radioactivity in aqueous solutions, were developed for low-level alpha radiation monitoring of natural waters. Resins were investigated with bis(2-ethylhexyl)methane-diphosphonic acid (H 2 DEH[MDP], Dipex[reg]) extractant, which has a strong affinity for tri-, tetra- and hexavalent actinides in dilute acids. Extractive scintillating resins were manifested (1) as a mixed bed of scintillating resin and extraction chromatographic resin and (2) by diffusing the organic fluor 2-(1-naphtyl)-5-phenyloxazole into macroporous polystyrene chromatographic resin, then coating with H 2 DEH[MDP], or by coating H 2 DEH[MDP] on scintillating polyvinyltoluene beads. The scintillation light was detected with a modified Hidex Triathler to allow for continuous flow measurements. The average detection efficiencies were 51.7±2.6% and 65.8±10.1% for natural uranium and 241 Am, respectively, for the extractant coated scintillator. The resin was stable for solution flow of up to 1000 ml resulting in rapid real-time quantification of natural uranium in groundwater down to 30 μg/ml

  19. An intensity monitor for solar hydrogen Lyman-alpha radiation (TAIYO SXU)

    International Nuclear Information System (INIS)

    Oshio, Takanori; Masuoka, Toshio; Higashino, Ichiro; Watanabe, Norihiko.

    1975-01-01

    The absolute intensity of hydrogen Lyman-alpha (1216A) from the total solar disk is currently monitored by an ion chamber as a part of the satellite mission of TAIYO. The apparatus consists of an ion chamber with a special input control mask and associated electronics. The ion chamber with an MgF 2 window and filled with NO gas is sensitive to a narrow spectral band including the Lα. The special mask serves to keep the angular response of the detector constant at the elevation angle of the sun relative to the plane perpendicular to the spinning axis of the satellite within an error of the order of one percent, when the angle is within +-30 0 . A flux reducer attenuates the incident radiation upon the detector by a factor of 20 to lengthen the life of detector. The associated electronics measures the output current of the ion chamber, holds the maximum value of the output every four-second period and sends it to the telemeter. From the currently observed data, the absolute intensity of the solar Lα is 3.2 x 10 11 photons/cm 2 sec and constant within +-4.2% during the period from 24 February to 31 May, 1975. (auth.)

  20. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity

    International Nuclear Information System (INIS)

    Kudryasheva, N.S.; Rozhko, T.V.

    2015-01-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1 – absence of effects (stress recognition), 2 – activation (adaptive response), and 3 – inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. - Highlights: • Luminous bacteria demonstrate nonlinear dose-effect relation in radioactive solutions. • Response to low-dose radiation includes 3 stages: threshold, activation, inhibition. • ROS are responsible for low-dose effects of alpha-emitting radionuclides. • Luminous marine bacteria are a convenient tool to study radiation hormesis

  1. Bystander effect of alpha-particle irradiation on mutagenicity and its associated mechanism

    International Nuclear Information System (INIS)

    Lu Ying; Yang Zhihua; Cao Zhenshan; Fan Feiyue; Zhu Maoxiang

    2004-01-01

    The work is to investigate α-particle irradiation-induced bystander effects on the mutagenicity in human chromosome 11 in the human-hamster hybrid (A L cells) and its possible mechanism. A L cells were used for assaying mutation rates of human chromosome 11 through screening mutants in the presence of anti-CD59 surface antigen antibody (S1) and complement. A grid was interposed between α-particle source and the cells being irradiated, so as to fix proportion of the irradiated cells (15%) and the bystander effects on the mutagenicity were detected. Free radical scavenger DMSO and intercellular communication inhibitor Lindane were selected to investigate the potential mechanism of α-particle induced bystander effect. There was clear dose-dependent relationship between mutation rate and the dose of alpha particle radiation. However, the mutant fractions of cell population shielded by the grid in α-particle irradiation system were much higher than the expected levels of irradiated cells. Lindane, but not DMSO, could obviously decrease this bystander effect induced by α-particle irradiation. Alpha-particle irradiation can induce bystander effect on the mutagenicity, in which intercellular communication may play important roles

  2. Topical Day on Biological Effects of Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Baatout, S.; Jacquet, P.

    1997-05-15

    The topical day has been focussed on the potential effects of ionizing radiation on human health. A general overview on molecular and biophysical aspects of radiation, its effects on cells and organisms, and the contribution of radiobiology to radiation protection and risk assessment is given. The genetic effects of radiation and its effects on the developing organism, the effects of radiation on the cell cycle and the mechanisms of radiation induced apoptosis were also discussed.

  3. Topical Day on Biological Effects of Radiation

    International Nuclear Information System (INIS)

    Baatout, S.; Jacquet, P.

    1997-01-01

    The topical day has been focussed on the potential effects of ionizing radiation on human health. A general overview on molecular and biophysical aspects of radiation, its effects on cells and organisms, and the contribution of radiobiology to radiation protection and risk assessment is given. The genetic effects of radiation and its effects on the developing organism, the effects of radiation on the cell cycle and the mechanisms of radiation induced apoptosis were also discussed

  4. Effects of radiation-counselling convergence education on radiation awareness

    Energy Technology Data Exchange (ETDEWEB)

    Seoung, Youl Hun [Dept. of Radiological Science, College of Health Science, Cheongju University, Cheongju (Korea, Republic of)

    2017-06-15

    The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit.

  5. Effects of radiation-counselling convergence education on radiation awareness

    International Nuclear Information System (INIS)

    Seoung, Youl Hun

    2017-01-01

    The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit

  6. Radiation, chemicals and combined effects

    International Nuclear Information System (INIS)

    Sinclair, W.K.

    1991-01-01

    A brief background has been provided on current carcinogenic risks from ionizing radiation and their magnitude in background circumstances. The magnitude of the risks from possibly carcinogenic chemicals at background levels in air, water and food are surprisingly similar. The exception is, perhaps, for the single source of radon which, while variable, on the average stands out above all other sources. Some basic principles concerning the interaction of combined radiation and chemicals and some practical examples where the two interact synergistically to enhance radiation effects has also been provided. Areas for human research in the future are discussed. (Author)

  7. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ( 211 At) and natural bismuth-212 ( 212 Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ( 223 Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  8. Reoxygenation of human coronary smooth muscle cells suppresses HIF-1{alpha} gene expression and augments radiation-induced growth delay and apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Grumann, T.; Arab, A.; Bode, C.; Hehrlein, C. [Dept. of Cardiology, Univ. Clinic of Freiburg (Germany); Guttenberger, R. [Dept. of Radiotherapy, Univ. Clinic of Freiburg (Germany)

    2006-01-01

    Background and Purpose: Catheter-based coronary brachytherapy with {beta}- and {gamma}-radiation is an evidence-based method to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA) and stent implantation, but the outcome may be PTCA are hypoxic. A lack of oxygen decreases the effect of low LET (linear energy transfer) irradiation. The authors assumed that reoxygenation of hypoxic human coronary smooth muscle cells (HCSMCs) improves the results of coronary brachytherapy. The expression of hypoxia-inducible factor 1{alpha} (HIF-1{alpha}) gene, and the rates of growth and apoptosis of hypoxic and reoxygenated HCSMCs after {gamma}-iradiation were therefore analyzed. Material and Methods: An in vitro model of megacolonies of HCSMCs was developed. After exposure to chronic hypoxia the HCSMCs were irradiated with graded doses of 2, 4, 8, and 16 Gy using a {sup 60}Co source either under hypoxia (pO{sub 2}<3 mmHg) or after reoxygenation (pO{sub 2}{approx}150 mmHg). RT-PCR (reverse transcription-polymerase chain reaction) analysis was used to quantify HIF-1{alpha} gene expression and the growth of HCSMC megacolonies was measured serially. The oxygen enhancement ratio (OER) was calculate from the specific growth delay. Apoptosis of HCSMCs was quantified by counting cells with specific DNA strand breaks using the TUNEL assy. Results: HIF-1{alpha} gene expression was markedly suppressed in reoxygenated cells versus hypoxic cells 30 min after {gamma}-irradiation at all radiation doses (158{+-}46% vs. 1,675{+-}1,211%; p<0.01). Apoptosis was markedly increased in reoxygenated HCSMCs. The OER was 1.8(95% CI[confidence interval]1.3-2.4). Therefore, reoxygenated HCSMCs require 44% less radiation dose to achieve the equivalent biological radiation effect compared to hypoxic HCSMCs. Conclusion: Reoxygenation of coronary smooth muscle cells should be considered an option to increase efficacy of coronary brachytherapy. This could be used to reduce radiation dose

  9. Measuring space radiation shielding effectiveness

    OpenAIRE

    Bahadori Amir; Semones Edward; Ewert Michael; Broyan James; Walker Steven

    2017-01-01

    Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles ...

  10. Radiation effects in optical components

    International Nuclear Information System (INIS)

    Friebele, E.J.

    1987-01-01

    This report discusses components of high performance optical devices may be exposed to high energy radiation environments during their lifetime. The effect of these adverse environments depends upon a large number of parameters associated with the radiation (nature, energy, dose, dose rate, etc.) or the system (temperature, optical performance requirements, optical wavelength, optical power, path length, etc.), as well as the intrinsic susceptibility of the optical component itself to degradation

  11. Environmental dosimetry and radiation effects

    International Nuclear Information System (INIS)

    Woodhead, D.S.

    1997-01-01

    Specific assessment of the potential effects on wild organisms of increased radiation exposure arising from the authorized disposal of radioactive wastes to the environment requires two interrelated sets of information. First, an estimate is required of the incremental radiation exposure; and second, dose rate-response relationships are necessary to predict the potential impact of the estimated incremental exposure. Each of these aspects will be discussed in detail. (author)

  12. Assessment of radiological risk parameters associated with some selected rivers around oil mineral producing sites in Abia State, Nigeria due to gross alpha and beta radiations

    International Nuclear Information System (INIS)

    Enyinna, Paschal Ikenna; Uzochukwu, Francis C.

    2016-01-01

    The study of gross alpha and beta radiation in environmental components and water bodies in particular is very crucial to the environmental, radiation and medical Physicist as this helps to promote good water quality and environmental hygiene. This research work understudied the radiological risk parameters due to gross alpha and beta radiations associated with three selected rivers around crude oil production sites in Abia State, Nigeria. Gross alpha and beta activities were computed for the three rivers based on analytical measurements carried out using a well-calibrated IN-20 model gas-flow proportional counter. Radiological risk parameters were computed from the activity concentrations which included; annual effective dose equivalent of radiation from ingested water (AEDE), annual gonadal dose equivalent (AGDE), and excess lifetime cancer risk (ELCR). The mean of the total AEDE due to the sum of alpha and beta radiations for the three rivers are 0.868 ± 0.221 mSv/y, 1.008 ± 0.156 mSv/y, and 0.917 ± 0.214 mSv/y; and are above the World Health Organization (WHO) permissible limit of 0.1 mSv/y. The mean of the total AGDE are 4.048 ± 1.063 mSv/y, 4.756 ± 0.739 mSv/y, and 4.295 ± 1.026 mSv/y; and are above the world average limit of 0.3 mSv/y. The mean of the total ELCR are (3.038 ± 0.774) X 10"-"3, (3.529 ± 0.547) X 10"-"3, and (3.210 ± 0.748) X 10"-"3; and are above the world average limit of 0.29 X 10"-"3. Most values of ELCR computed in this work are >6.0 X 10"-"4 estimated to be the risk of fatal and weighted nonfatal health conditions over a lifetime (70 years) derived from the radiation dose of 0.1 mSv/y (WHO permissible limit for drinking water). Drinking water from these surveyed sources could impact negatively on the end users. (author)

  13. Relative response of TL and component-resolved OSL to alpha and beta radiations in annealed sedimentary quartz

    International Nuclear Information System (INIS)

    Polymeris, George S.; Afouxenidis, Dimitrios; Raptis, Spyridoula; Liritzis, Ioannis; Tsirliganis, Nestor C.; Kitis, George

    2011-01-01

    Knowledge of the relative luminescence response to alpha and beta radiation is very important in TL and OSL dating. In the present study the relative alpha to beta response is studied in a sedimentary quartz sample, previously fired at 900 deg. C for 1 h, in the dose region between 1 and 128 Gy, for both thermoluminescence (TL) and linearly modulated optically stimulated luminescence (LM - OSL). The LM - OSL measurements were performed at room temperature and at 125 deg. C. All OSL signals were deconvolved into their individual components. Comparison of OSL curves after alpha and beta irradiation strongly supports that quartz OSL components follow first order kinetics in both cases. In the case of TL, the relative alpha to beta response is found to be very different for each TL glow-peak, but it does not depend strongly on irradiation dose. In the case of LM - OSL measurements, it is found that the relative behaviour of the alpha to beta response is different for three distinct regions, namely the fast OSL component, the region of medium OSL component originating from the TL glow-peak at 110 deg. C when stimulation takes place at room temperature and finally the region of slow OSL component. Following stimulation at ambient temperature, the relative alpha to beta response of all components was not observed to depend significantly on dose, with the value of ratio being 0.03 and a tendency to decrease with increasing dose. However, in the case of measurements performed at 125 deg. C, the relative response of the fast components is much enhanced, and for the remaining components it increases with increasing dose. Special care must be taken to examine the relative alpha to beta response of the fast component at 125 deg. C which contrasts the relative response of the TL peak at ca. 325 deg. C. The implications for the dating of annealed quartz are also briefly discussed. - Highlights: → Relative alpha to beta response for TL and LM-OSL is studied in annealed

  14. Variance of the number of tumors in a model for the induction of osteosarcoma by alpha radiation

    International Nuclear Information System (INIS)

    Groer, P.G.; Marshall, J.H.

    1976-01-01

    An earlier report on a model for the induction of osteosarcoma by alpha radiation gave differential equations for the mean numbers of normal, transformed, and malignant cells. In this report we show that for a constant dose rate the variance of the number of cells at each stage and time is equal to the corresponding mean, so the numbers of tumors predicted by the model have a Poisson distribution about their mean values

  15. Radiation effects at the SSC

    Energy Technology Data Exchange (ETDEWEB)

    Gilchriese, M.G.D. [ed.] [Superconducting Super Collider Lab., Dallas, TX (United States)

    1988-06-01

    This report contains a preliminary study of the effects of the radiation levels expected at the SSC on potential detector components and a subset of materials to be used in the SSC accelerators. The report does not contain a discussion of radiation damage to electronics components that may be used at the SSC. We have investigated many of the effects of radiation on silicon detectors, on wire chambers, on scintillating materials and the associated readout, on optical fibers for data transmission and on structural or other materials to be used in detector or accelerator components. In the SSC accelerator complex, in particular the storage rings, radiation damage will not present significant problems different than those now faced by existing high energy accelerators. We find that the effects of radiation damage on SSC detector components will be significant at the design luminosity of the ssc and will limit, or determine, many of the options for different detector components. In this regard the reader should keep in mind that, in the absence of a specific detector design, it is not possible to form definitive conclusions regarding the viability of the detector components. Since the radiation levels in experiments at the SSC will depend on the geometry and composition of the apparatus, simple yes /no generalizations about the feasibility of a detector component are not possible.

  16. Radiation-induced changes in production of prostaglandins Fsub(2. cap alpha. ), E, and thromboxane B/sub 2/ in guinea pig parenchymal lung tissues

    Energy Technology Data Exchange (ETDEWEB)

    Steel, L K; Catravas, G N [Armed Forces Radiobiology Research Inst., Bethesda, MD (USA)

    1982-11-01

    At 1 hour to 4 days after unilateral exposure of guinea pigs to a single dose (0.5, 1.5, or 3.0 Gy) of gamma-radiation, changes were detected in prostaglandin and thromboxane concentrations in parenchymal lung tissues. At 1-3 hours after exposure, tissue levels of PGFsub(2..cap alpha..), PGE, and thromboxane B/sub 2/ were significantly elevated in animals receiving 3.0 Gy, with the magnitude of alteration revealing a radiation dose effect. By 24 hours, tissue prostaglandin and thromboxane levels returned to near control values. Lung tissue synthesis of prostaglandins in response to H-1 receptor stimulation by the exogenous addition of histamine revealed similar radiation dose effects. The carboxylic acid ionophore A23187, exogenously applied to lung tissues, revealed a transient peak of increased sensitivity to ionophore stimulation for TxB/sub 2/ synthesis at 24 hours and for PGFsub(2..cap alpha..) at 72 hours post-irradiation. The data suggest that significant alterations in prostaglandin and thromboxane concentrations in parenchymal lung tissues occur following irradiation, in a dose-dependent manner, and that altered responsiveness to H-1 receptor stimulation and divalent cation transport also occur.

  17. Health effects of ionising radiation

    International Nuclear Information System (INIS)

    Mohammadi, S.

    2000-01-01

    Human and animal studies have shown an increased incidence of cancer and malformation due to radioactive materials and external radiation. The biological effects of radiation on tissues are the occurrence of morphological and functional changes in the body. The critical parts of the body are those tissues or organs which when irradiated, are likely to influence the health of the individual or its offspring. The probability of these changes depends on the radiation dose. There are two main types of damage due to radiation dose. Radiation Sickness with well-defined symptoms like cancer and inherited disorders which can appear after several years. A second type of damage, namely Acute Radiation Sickness results after exposure of the whole or parts of the body to high doses of radiation greater than 1 Gy. There are safety standards for the amount of dose equivalent that is taken as acceptable. The International Commission on Radiological Protection (ICRP) has given norms in which natural and medical causes were not included. These are given as recommended values (1966) and proposed values (2000), both in mSv/yr: population at large: 1.7 and 0.4; members of the public: 5 and 2; and radiologic workers: 50 and 20, respectively. Taking into account the increased number of reactor accidents, the question is how safe is our safety standards? Even when one is able to connect a quantitative risk with a radiation dose, there are three fundamental principles which we should obey in dealing with risks from radiation. These are: (1) Avoid any risk. (2) The risk should be related to the possible benefit. (3) Any dose below the politically agreed limits is acceptable

  18. Harmful effects of ultraviolet radiation

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Tanning for cosmetic purposes by sunbathing or by using artificial tanning devices is widespread. The hazards associated with exposure to ultraviolet radiation are of concern to the medical profession. Depending on the amount and form of the radiation, as well as on the skin type of the individual exposed, ultraviolet radiation causes erythema, sunburn, photodamage (photoaging), photocarcinogenesis, damage to the eyes, alteration of the immune system of the skin, and chemical hypersensitivity. Skin cancers most commonly produced by ultraviolet radiation are basal and squamous cell carcinomas. There also is much circumstantial evidence that the increase in the incidence of cutaneous malignant melanoma during the past half century is related to increased sun exposure, but this has not been proved. Effective and cosmetically acceptable sunscreen preparations have been developed that can do much to prevent or reduce most harmful effects to ultraviolet radiation if they are applied properly and consistently. Other safety measures include (1) minimizing exposure to ultraviolet radiation, (2) being aware of reflective surfaces while in the sun, (3) wearing protective clothing, (4) avoiding use of artificial tanning devices, and (5) protecting infants and children

  19. Biological effects of nuclear radiation

    International Nuclear Information System (INIS)

    Hotz, G.

    1975-01-01

    After a brief survey about the main radiobiological effects caused by ionizing radiation, human symptoms after irradiation and incorporation are shown. The special radiotoxic effect of radionuclides which are chemically associated with metabolism-specific elements such as calcium and potassium is shown and methods of treatment are indicated. (ORU) [de

  20. Radiation Effects in Carbon Nanoelectronics

    Directory of Open Access Journals (Sweden)

    Cory D. Cress

    2012-07-01

    Full Text Available We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  1. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

  2. Mathematical models for radiation effects on human health

    International Nuclear Information System (INIS)

    Negi, U.S.; Petwal, K.C.

    2015-01-01

    In this paper, we are proposing a theoretical approach of basic mathematical models for radiation effect on human health. The largest natural sources of radiation exposure to humans are radon gas. While radon gas has always been in the environment, awareness of its contribution to human radiation exposure has increased in recent years. Radon's primary pathway is through air space in soil and rock. Pressure differences between the soil and the inside of buildings may cause radon gas to move indoors. Radon decays to radon daughters, some of which emit alpha radiation. Alpha-emitting radon daughters are adsorbed on to dust particles which, when inhaled, are trapped in the lungs and may cause gene damage, mutations and finally cancer. Exposure to excess UV radiation increases risk of skin cancer but there is also a dark side. The incidence of all types of skin cancer is related to exposure to UV radiation. Non-melanoma skin cancer, eye melanoma, and lip cancer have also been related to natural UV light

  3. Effects of x-ray irradiation on the induction of. cap alpha. -amylase synthesis by gibberelic acid in the aleurone system of barley

    Energy Technology Data Exchange (ETDEWEB)

    Zellner, H

    1974-01-01

    The influence of ionizing radiation on a system without DNA replication and cell division was investigated with the aid of GA/sub 3/-induced ..cap alpha..-amylase synthesis in aleurone cells of barley. The reaction of the system was determined by dose effect curves (after irradiation of one half of the endosperms in rest) for the synthesis and secretion of ..cap alpha..-amylase, protein, and reducing sugars. The system proves to be highly radiation-resistant. The course of the synthesis of ..cap alpha..-amylase after X-ray irradiation with varying doses during enzyme synthesis suggests that transcription occurs in the middle of the lag-phase and is the most sensitive stage in enzyme synthesis, while translation alone is less sensitive to radiation.

  4. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, W.T.; Walker, B.A. [Environmental Evaluation Group, Albuquerque, NM (United States)

    1997-08-01

    Waste Isolation Pilot Plant (WIPP) alpha continuous air monitor (CAM) performance was evaluated to determine if CAMs could detect accidental releases of transuranic radioactivity from the underground repository. Anomalous alpha spectra and poor background subtraction were observed and attributed to salt deposits on the CAM sampling filters. Microscopic examination of salt laden sampling filters revealed that aerosol particles were forming dendritic structures on the surface of the sampling filters. Alpha CAM detection efficiency decreased exponentially as salt deposits increased on the sampling filters, suggesting that sampling-filter salt was performing like a fibrous filter rather than a membrane filter. Aerosol particles appeared to penetrate the sampling-filter salt deposits and alpha particle energy was reduced. These findings indicate that alpha CAMs may not be able to detect acute releases of radioactivity, and consequently CAMs are not used as part of the WIPP dynamic confinement system. 12 refs., 12 figs., 1 tab.

  5. Kinetic theory of radiation effects

    International Nuclear Information System (INIS)

    Mansur, L.K.

    1987-01-01

    To help achieve the quantitative and mechanistic understanding of these processes, the kinetic theory of radiation effects has been developed in the DOE basic energy sciences radiation effects and fusion reactor materials programs, as well as in corresponding efforts in other countries. This discipline grapples with a very wide range of phenomena and draws on numerous sub-fields of theory such as defect physics, diffusion, elasticity, chemical reaction rates, phase transformations and thermodynamics. The theory is cast in a mathematical framework of continuum dynamics. Issues particularly relevant to the present inquiry can be viewed from the standpoints of applications of the theory and areas requiring further progress

  6. Transforming growth factor alpha is a critical mediator of radiation lung injury.

    Science.gov (United States)

    Chung, Eun Joo; Hudak, Kathryn; Horton, Jason A; White, Ayla; Scroggins, Bradley T; Vaswani, Shiva; Citrin, Deborah

    2014-09-01

    Radiation fibrosis of the lung is a late toxicity of thoracic irradiation. Epidermal growth factor (EGF) signaling has previously been implicated in radiation lung injury. We hypothesized that TGF-α, an EGF receptor ligand, plays a key role in radiation-induced fibrosis in lung. Mice deficient in transforming growth factor (TGF-α(-/-)) and control C57Bl/6J (C57-WT) mice were exposed to thoracic irradiation in 5 daily fractions of 6 Gy. Cohorts of mice were followed for survival (n ≥ 5 per group) and tissue collection (n = 3 per strain and time point). Collagen accumulation in irradiated lungs was assessed by Masson's trichrome staining and analysis of hydroxyproline content. Cytokine levels in lung tissue were assessed with ELISA. The effects of TGF-α on pneumocyte and fibroblast proliferation and collagen production were analyzed in vitro. Lysyl oxidase (LOX) expression and activity were measured in vitro and in vivo. Irradiated C57-WT mice had a median survival of 24.4 weeks compared to 48.2 weeks for irradiated TGF-α(-/-) mice (P = 0.001). At 20 weeks after irradiation, hydroxyproline content was markedly increased in C57-WT mice exposed to radiation compared to TGF-α(-/-) mice exposed to radiation or unirradiated C57-WT mice (63.0, 30.5 and 37.6 μg/lung, respectively, P = 0.01). C57-WT mice exposed to radiation had dense foci of subpleural fibrosis at 20 weeks after exposure, whereas the lungs of irradiated TGF-α (-/-) mice were largely devoid of fibrotic foci. Lung tissue concentrations of IL-1β, IL-4, TNF-α, TGF-β and EGF at multiple time points after irradiation were similar in C57-WT and TGF-α(-/-) mice. TGF-α in lung tissue of C57-WT mice rose rapidly after irradiation and remained elevated through 20 weeks. TGF-α(-/-) mice had lower basal LOX expression than C57-WT mice. Both LOX expression and LOX activity were increased after irradiation in all mice but to a lesser degree in TGF-α(-/-) mice. Treatment of NIH-3T3 fibroblasts with TGF

  7. Radiation research contracts: Biological effects of small radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Hug, O [International Atomic Energy Agency, Division of Health, Safety and Waste Disposal, Vienna (Austria)

    1959-04-15

    To establish the maximum permissible radiation doses for occupational and other kinds of radiation exposure, it is necessary to know those biological effects which can be produced by very small radiation doses. This particular field of radiation biology has not yet been sufficiently explored. This holds true for possible delayed damage after occupational radiation exposure over a period of many years as well as for acute reactions of the organism to single low level exposures. We know that irradiation of less than 25 Roentgen units (r) is unlikely to produce symptoms of radiation sickness. We have, however, found indications that even smaller doses may produce certain instantaneous reactions which must not be neglected

  8. Health effects of ionizing radiation

    International Nuclear Information System (INIS)

    Radford, E.P.

    1980-01-01

    This presentation is restricted to the health effects of low doses of ionizing radiation. In general, these cumulative exposures are well below 100 rem, or about 50 times background or less. The two effects of interest in this dose range are genetic mutations and cancer production. The genetic effects will not be discussed in detail. The chief reason for the rise in risk estimates for cancer is the longer follow-up of exposed populations

  9. Effect of alpha particles on Toroidal Alfven Eigenmodes

    International Nuclear Information System (INIS)

    Berk, H.L.

    1992-11-01

    An overview is given of the analytic structure for the linear theory of the Toroidal Alfven Eigenmode (TAE), where multiple gap structures occur. A discussion is given of the alpha particle drive and the various dissipation mechanisms that can stabilize the system. A self-consistent calculation of the TAE mode, for a low-beta high-aspect-ratio plasma, indicates that though the alpha particle drive is comparable to the dissipation mechanisms, overall stability is still achieved for ignited ITER-like plasma. A brief discussion is given of the nonlinear theory for the TAE mode and how nonlinear alpha particle dynamics can be treated by mapping methods

  10. Experimental study on the effects of recombinant adenoviral-mediated mI{kappa}B{alpha} gene combined with irradiation on the treatment of hepatocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kejun, Zhang; Dechun, Li; Dongming, Zhu [The First Affiliated Hospital to Suzhou Univ., Suzhou (China); Caixia, Song

    2007-10-15

    Objective: To explore the effect of recombinant adenovirus vector mediated mutant I{kappa}B{alpha} (mI{kappa}B{alpha}) combined with radiation on the hepatocarcinoma. Methods: Limited dilution method was used to test the virus titer in 293 cells. The HCC9204 cells were infected with MOI 10,20,30 and 50 for 48 h, respectively. The expression of p65 and mI{kappa}B{alpha} protein was analyzed by Western blot. Transfected HCC9204 cells and controls were treated with 4 Gy {gamma} rays. The inhibition rate of HCC9204 cells was examined by MTT. Rat models of HCC9204 was constructed. AdmI{kappa}B{alpha} plasmids were injected into tumor tissue and the tumors were administered with 6 Gy {gamma} irradiation 48 hours later. Tumor growth at different time points was recorded during 28 days. Results: The titer of AdmI{kappa}B{alpha} is 1.252 x 10{sup 9} pfu/ml. The expression of mI{kappa}B{alpha} protein was increased with titer of AdmI{kappa}B{alpha}, and p65 protein began to decrease when MOI was 10, and reached the lowest when MOI was 50, they were all dose-dependent. The proliferation of HCC9204 cell lines were suppressed, as was more significant combined with radiation, and the effect was in a viral dose-dependent manner. From days 7 to 28 after AdmI{kappa}B{alpha} gene and radiotherapy, the tumor growth was significantly slower than after irradiation or gene therapy alone. Conclusions: Recombinant adenoviral-mediated mI{kappa}B{alpha} gene, combined with irradiation, can increase the cell-killing effect. It is better than that of either one alone. (authors)

  11. Destabilizing effect of alpha particles in a Maxwellian plasma

    International Nuclear Information System (INIS)

    Wang, M.Y.

    1976-01-01

    Various plasma waves which are possibly excited by MeV alphas have been investigated. For a delta birth distribution it is found that: a) The right-circularly polarized Alfven wave can be excited. Its growth rate is linearly proportional to the α-particle density. b) The drift Alfven wave is stable against α-particles. c) For a uniform temperature, the plasma wave spectrum changes from three branches with n/sub α/ = 0 to four branches for n/sub α/ not equal to 0 case. d) α-particles can destabilize the ion drift acoustic wave even with uniform temperature. However, the ion acoustic wave appears to be stable against fusion products in a fusion grade plasma. e) If their effect on the background plasma spectrum is neglected, α-particles can excite the electromagnetic cyclotron wave in a range of harmonics (band structure). The growth rate is proportional to the square root of α-particle density. f) If the effect of α-particle on the plasma spectrum is included, we find that electromagnetic cyclotron wave is stable

  12. Effects of alpha-decay on spent fuel corrosion behaviour

    International Nuclear Information System (INIS)

    Wiss, T.; Rondinella, V.V.; Cobos, J.; Wegen, D.H.; Amme, M.; Ronchi, C.

    2004-01-01

    An overview of results in the area of spent fuel characterization as nuclear waste is presented. These studies are focused on primary aspects of spent fuel corrosion, by considering different fuel compositions and burn ups, as well as a wide set of environmental conditions. The key parameter is the storage time of the fuel e.g. in view of spent fuel retrieval or in view of its final disposal. To extrapolate data obtainable from a laboratory-acceptable timescale to those expected after storage periods of interest have elapsed (amounting in the extreme case to geological ages) is a tough challenge. Emphasis is put on key aspects of fuel corrosion related to fuel properties at a given age and environmental conditions expected in the repository: e.g. the fuel activity (radiolysis effects), the effects of helium build-up and of groundwater composition. A wide range of techniques, from traditional leaching experiments to advanced electrochemistry, and of materials, including spent fuel with different compositions/burnups and analogues like the so-called alpha-doped UO 2 , are employed for these studies. The results confirm the safety of European underground repository concepts. (authors)

  13. Stimulating effects of ionizing radiation

    International Nuclear Information System (INIS)

    Jaworowski, Z.

    1995-01-01

    The influence of low doses on human organism is not definite known up to now. The worldwide discussion on this topic has been presented. A lot of analysed statistical data proved that the stimulating effect of low doses of ionizing radiation really exists and can have a beneficial influence on human health. 43 refs, 4 figs, 6 tabs

  14. Radiation effects on video imagers

    International Nuclear Information System (INIS)

    Yates, G.J.; Bujnosek, J.J.; Jaramillo, S.A.; Walton, R.B.; Martinez, T.M.; Black, J.P.

    1985-01-01

    Radiation sensitivity of several photoconductive, photoemissive, and solid state silicon-based video imagers was measured by analyzing stored photocharge induced by irradiation with continuous and pulsed sources of high energy photons and neutrons. Transient effects as functions of absorbed dose, dose rate, fluences, and ionizing particle energy are presented

  15. Biopositive Effects of Ionizing Radiation?

    International Nuclear Information System (INIS)

    Broda, E.

    1972-01-01

    This paper was written for a talk given by E. Broda in Vienna for an event organised by the chemical physical society, the Austrian biochemical society and the Austrian biophysical society in December 1972. In this paper Broda analyses the question of biopositive effects of ionizing radiation. (nowak)

  16. SM22{alpha}-induced activation of p16{sup INK4a}/retinoblastoma pathway promotes cellular senescence caused by a subclinical dose of {gamma}-radiation and doxorubicin in HepG2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Rim; Lee, Hee Min; Lee, So Yong; Kim, Eun Jin; Kim, Kug Chan [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Paik, Sang Gi [Department of Biology, School of Biosciences and Biotechnology, Chungnam National University, Daejeon (Korea, Republic of); Cho, Eun Wie, E-mail: ewcho@kribb.re.kr [Daejeon-KRIBB-FHCRC Cooperation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, In Gyu, E-mail: igkim@kaeri.re.kr [Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-09-10

    Research highlights: {yields} SM22{alpha} overexpression in HepG2 cells leads cells to a growth arrest state, and the treatment of a subclinical dose of {gamma}-radiation or doxorubicin promotes cellular senescence. {yields} SM22{alpha} overexpression elevates p16{sup INK4a} followed by pRB activation, but there are no effects on p53/p21{sup WAF1/Cip1} pathway. {yields} SM22{alpha}-induced MT-1G activates p16{sup INK4a}/pRB pathway, which promotes cellular senescence by damaging agents. -- Abstract: Smooth muscle protein 22-alpha (SM22{alpha}) is known as a transformation- and shape change-sensitive actin cross-linking protein found in smooth muscle tissue and fibroblasts; however, its functional role remains uncertain. We reported previously that SM22{alpha} overexpression confers resistance against anti-cancer drugs or radiation via induction of metallothionein (MT) isozymes in HepG2 cells. In this study, we demonstrate that SM22{alpha} overexpression leads cells to a growth arrest state and promotes cellular senescence caused by treatment with a subclinical dose of {gamma}-radiation (0.05 and 0.1 Gy) or doxorubicin (0.01 and 0.05 {mu}g/ml), compared to control cells. Senescence growth arrest is known to be controlled by p53 phosphorylation/p21{sup WAF1/Cip1} induction or p16{sup INK4a}/retinoblastoma protein (pRB) activation. SM22{alpha} overexpression in HepG2 cells elevated p16{sup INK4a} followed by pRB activation, but did not activate the p53/p21{sup WAF1/Cip1} pathway. Moreover, MT-1G, which is induced by SM22{alpha} overexpression, was involved in the activation of the p16{sup INK4a}/pRB pathway, which led to a growth arrest state and promoted cellular senescence caused by damaging agents. Our findings provide the first demonstration that SM22{alpha} modulates cellular senescence caused by damaging agents via regulation of the p16{sup INK4a}/pRB pathway in HepG2 cells and that these effects of SM22{alpha} are partially mediated by MT-1G.

  17. Modification of radiation effects

    International Nuclear Information System (INIS)

    Lindenbaum, A.

    1975-01-01

    Results are reported from studies on the tissue distribution of 239 Pu and 241 Am in mice and beagle dogs and the effectiveness of various therapeutic treatments for decorporation. In dogs injected with monomeric Pu the value of a regimen of early and prolonged treatment with DTPA (diethylenetriaminepentaacetic acid) for minimizing the Pu burden in the soft tissues and skeleton was demonstrated. These results have immediate implication for DTPA treatment in man. New studies in mice verified the action of pyran copolymer antiviral agents in enhancing the effectiveness of DTPA for removal of polymeric Pu from the liver. Recent application of autoradiographic procedures for quantitatively comparing short- and long-term localization of monomeric and polymeric 239 Pu in dog liver showed that there is no net translocation of monomeric Pu within the liver between 6 and 90 days following injection. One of the molecular studies presently underway aims at synthesis of a variety of DTPA esters. The diethyl ester has already been prepared and tested for toxicity in mice. These compounds are designed to bring DTPA into contact with plutonium deposits unavailable to the action of ionic DTPA. (U.S.)

  18. Radiation effects on eye components

    Science.gov (United States)

    Durchschlag, H.; Fochler, C.; Abraham, K.; Kulawik, B.

    1999-08-01

    The most important water-soluble components of the vertebrate eye (lens proteins, aqueous humor, vitreous, hyaluronic acid, ascorbic acid) have been investigated in aqueous solution, after preceding X- or UV-irradiation. Spectroscopic, chromatographic, electrophoretic, hydrodynamic and analytic techniques have been applied, to monitor several radiation damages such as destruction of aromatic and sulfur-containing amino acids, aggregation, crosslinking, dissociation, fragmentation, and partial unfolding. Various substances were found which were able to protect eye components effectively against radiation, some of them being also of medical relevance.

  19. Effect of alpha-tocopherol and alpha-tocopheryl quinone on the radiosensitivity of thiol-depleted mammalian cells

    International Nuclear Information System (INIS)

    Hodgkiss, R.J.; Stratford, M.R.; Watfa, R.R.

    1989-01-01

    The effect of hypoxic cell radiosensitizers is increased when mammalian cells are depleted of endogenous glutathione by buthionine sulphoximine pre-treatment in vitro; a similar gain has not been observed in tumors in vivo despite evidence of glutathione depletion in vivo following buthionine sulphoximine treatment. However, concentrations of biological reducing agents other than glutathione were not measured in the in vivo experiments. Other reducing agents found in tumors include alpha-tocopherol, which reduces the sensitizing efficiency of nitro-aromatic sensitizers in thiol-depleted mammalian cells. These data suggest that the failure to observe large gains in misonidazole sensitizing efficiency in thiol-depleted tumors in vivo may be due, in part, to the presence of biological reducing agents such as alpha-tocopherol

  20. Phase 2 Randomized Controlled Trial of Radiation Therapy Plus Concurrent Interferon-Alpha and Retinoic Acid Versus Cisplatin for Stage III Cervical Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Partha, E-mail: BasuP@iarc.fr [Screening Group, Early Detection and Prevention Section, International Agency for Research on Cancer, Lyon (France); Jenson, Alfred Bennett [James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky (United States); Majhi, Tapas; Choudhury, Prabir [Department of Radiation Oncology, Chittaranjan National Cancer Institute, Kolkata (India); Mandal, Ranajit; Banerjee, Dipanwita [Department of Gynecological Oncology, Chittaranjan National Cancer Institute, Kolkata (India); Biswas, Jaydip [Department of Surgical Oncology, Chittaranjan National Cancer Institute, Kolkata (India); Pan, Jianmin; Rai, Shesh Nath; Ghim, Shin je; Miller, Donald [James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky (United States)

    2016-01-01

    Purpose: Because a combination of retinoic acid, interferon-alpha, and radiation therapy demonstrated synergistic action and effectiveness to treat advanced cervical cancers in earlier studies, we designed this randomized phase 2 open-label trial to assess efficacy and safety of interferon alpha-2b (IFN) and 13-cis-retinoic acid (RA) administered concomitantly with radiation therapy (IFN-RA-radiation) to treat stage III cervical cancer. Methods and Materials: Stage III cervical cancer patients were randomized to study and control groups in a 1:1 ratio. All patients were treated with radiation therapy; study arm patients received IFN (3 × 10{sup 6} IU subcutaneously) 3 times a week for 4 weeks and daily RA (40 mg orally) for 30 days starting on day 1 of radiation, whereas control arm patients received weekly cisplatinum (40 mg/m{sup 2}) for 5 weeks during radiation. Patients were followed for 3 years. The primary endpoint was overall survival at 3 years. Results: Patients in the study (n=104) and control (n=105) groups were comparable for clinicopathological characteristics, radiation therapy–related variables and treatment response. Proportions of disease-free patients in the study and control groups were 38.5% and 44.8%, respectively, after median follow-up of 29.2 months. Hazard ratios were 0.67 (95% confidence interval [CI]: 0.44-1.01) and 0.69 (95% CI: 0.44-1.06) for overall and disease-fee survival, respectively, comparing the study group to control, and demonstrated an inferior outcome with RA-IFN-radiation, although differences were statistically nonsignificant. Kaplan-Meier curves of disease-free and overall survival probabilities also showed inferior survival in the study group compared to those in the control. Acute toxicities of chemoradiation were significantly higher with 2 acute toxicity-related deaths. Conclusions: Treatment with RA-IFN-radiation did not demonstrate survival advantage over chemoradiation despite being less toxic. The

  1. Effective radiological contamination control and monitoring techniques in high alpha environments.

    Science.gov (United States)

    Funke, Kevin C

    2003-02-01

    In the decommissioning of a highly contaminated alpha environment, such as the one at Hanford's 233-S Plutonium Concentration Facility, one of the key elements of a successful radiological control program is an integrated safety approach. This approach begins with the job-planning phase where the scope of the work is described. This is followed by a brainstorming session involving engineering and craft to identify how to perform the work in a logical sequence of events. Once the brainstorming session is over, a Job Hazard Analysis is performed to identify any potential problems. Mockups are utilized to enable the craft to get hands on experience and provide feedback and ideas to make the job run smoother. Ideas and experience gained during mockups are incorporated into the task instruction. To assure appropriate data are used in planning and executing the job, our principal evaluation tools included lapel and workplace air sampling, plus continuous air monitors and frequent surveys to effectively monitor job progress. In this highly contaminated alpha environment, with contamination levels ranging from 0.3 Bq cm-2 to approximately 100,000 Bq cm-2 (2,000 dpm per 100 cm2 to approximately 600 million dpm per 100 cm2), with average working levels of 1,600-3,200 Bq cm-2 (10-20 million dpm per 100 cm2) without concomitant ambient radiation levels, control of the spread of contamination is key to keeping airborne levels As Low As Reasonably Achievable.

  2. Radiation Effects in Paediatric radiography

    International Nuclear Information System (INIS)

    Mutwasi, O.

    2006-01-01

    Diagnostic imaging has evolved from single technique to a field which we have a choice from many modalities. Some without radiation. Radiation producing modalities include plain films (low dose), Fluoroscopy (mid range dose), Computed tomography (high dose). Radiography dose can significantly be influenced in plain radiography by varying speed of screens, cassette construction and type of radiography. E.g. digital or computed. In computed or digital radiography we are no longer able to tell h igh dose b y the quality of images. The final image is by great extend a product of post processing algorithms. It's for this reasons that the basic understanding of the sensitivity and specifying of various types of examinations and of specifically radiation effects is mandatory for a paediatric imager

  3. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

    2007-11-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

  4. Biological radiation effects

    International Nuclear Information System (INIS)

    Russo, A.

    2000-01-01

    Everyone is exposed to a complex mix of electromagnetic fields (EMF) of different frequencies that permeate our environment. Exposures to these EMF are increasing significantly as technology advances unabated and new applications are found. Technological progress in the broadest sense of the word has always been associated with various hazards and risks, both perceived and real. The industrial, commercial and household application on EMF is no exception. Throughout the world, the general public is concerned that exposure to EMF from such sources as high voltage power lines, broadcasting networks, mobile telephones and their base stations could lead to adverse health consequences, especially in children. As a result, the construction of new power lines and broadcasting and mobile telephone network has met with considerable opposition in many countries. Public exposure to EMF is regulated by a variety of voluntary and legal limits, together with various national safety standards. Guidelines are designed to avoid all identified hazards, from short and long term exposure, recommended limits. The aim of this paper is to report the summary of the actual scientific knowledge about the potential health effects and hazards due to man made EMF and the new tendencies of the social and political choices [it

  5. Dual Effects of Alpha-Hydroxy Acids on the Skin

    Directory of Open Access Journals (Sweden)

    Sheau-Chung Tang

    2018-04-01

    Full Text Available AHAs are organic acids with one hydroxyl group attached to the alpha position of the acid. AHAs including glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid are often used extensively in cosmetic formulations. AHAs have been used as superficial peeling agents as well as to ameliorate the appearance of keratoses and acne in dermatology. However, caution should be exercised in relation to certain adverse reactions among patients using products with AHAs, including swelling, burning, and pruritus. Whether AHAs enhance or decrease photo damage of the skin remains unclear, compelling us to ask the question, is AHA a friend or a foe of the skin? The aim of this manuscript is to review the various biological effects and mechanisms of AHAs on human keratinocytes and in an animal model. We conclude that whether AHA is a friend or foe of human skin depends on its concentration. These mechanisms of AHAs are currently well understood, aiding the development of novel approaches for the prevention of UV-induced skin damage.

  6. Alpha radiation-induced alterations of the proliferation kinetics, chromatin structure and gene expression in mammalian cells

    International Nuclear Information System (INIS)

    Hieber, L.

    1983-01-01

    Exponentially growing mammalian cells were exposed to 3.4 MeV alpha particles. The chromatin of cells arrested in G2 by alpha irradiation was severely damaged, though all cells were still capable to condensate their chromatin after fusion with mitotic cells. In addition to the common types of aberrations (breaks, gaps, dicentrics and exchanges) cells were found possessing one or more chromosomes with long stretches of undercondensed chromatin. Repair of these lesions was indicated by site specific unscheduled DNA synthesis and by the observation that condensation of these regions improved during G2 arrest. Furthermore, during G2 arrest the synthesis of two cellular proteins was stimulated. This was studied by two-dimensional gel electrophoresis of 35 S-methionine labeled cellular proteins. All these findings provided evidence that radiation-induced G2 arrest is caused by chromatin damage, which prevents regular chromosome condensation for mitosis. (orig./MG) [de

  7. Alpha slow-moving high-density-lipoprotein subfraction in serum of a patient with radiation enteritis and peritoneal carcinosis

    International Nuclear Information System (INIS)

    Peynet, J.; Legrand, A.; Messing, B.; Thuillier, F.; Rousselet, F.

    1989-01-01

    An alpha slow-moving high-density-lipoprotein (HDL) subfraction was seen in a patient presenting with radiation enteritis and peritoneal carcinosis, who was given long-term cyclic parenteral nutrition. This subfraction, observed in addition to normal HDL, was precipitated with low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL) by sodium phosphotungstate-magnesium chloride. The patient's serum lipoproteins were analyzed after fractionation by density gradient ultracentrifugation. The alpha slow-moving HDL floated in the ultracentrifugation subfractions with densities ranging from 1.028 to 1.084 kg/L, and their main apolipoproteins included apolipoprotein E in addition to apolipoprotein A-I. These HDL were larger than HDL2. The pathogenesis of this unusual HDL subfraction is hypothesized

  8. Effectiveness and Mechanisms of Antagonism of Toxic Effects of Cyanide by Alpha-Keto Acids.

    Science.gov (United States)

    1986-12-31

    until the miss-w near death. Lethal blood levels of cyanide in alpha-KG treated animl. as levels of 5-7 mcg cyani0e, which so 5-7 times the expected...lethal levels . rwm these studies, alpha-KC is effettive in antagonising administered dos of CH of five time the lethal dose before the toxic effects are...parameters in the dog .................. 26 Table 6 The effects of cyanide on 2,3 diphosphoglyceric acid .......... 28 Table 7 Stability of solution of ci

  9. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    1996-01-01

    The Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Tm), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, Tecogen, a division of Thermo Power Corporation, a Thermo Electron company, is developing a real-time, field-deployable, alpha monitor based on a solid-state silicon wafer semiconductor (patent pending, to be assigned to the Department of Energy). The Thermo Alpha Monitor (TAM) will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste Focus Area and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This instrument for direct counting of alpha-emitters in aqueous streams is presently being developed by Thermo Power under a development program funded by the DOE Environmental Management program (DOE-EM), administered by the Morgantown Energy Technology Center (METC). Under this contract, Thermo Power has demonstrated a solid-state, silicon-based semiconductor instrument, which uses a proprietary film-based collection system to quantitatively extract the

  10. The biological effectiveness of heavy ion radiations in the environment

    International Nuclear Information System (INIS)

    Craven, P.A.

    1996-03-01

    Although heavy ions are rarely encountered in the majority of terrestrial environments, the exposure of humans to this fascinating class of ionizing radiation is becoming more frequent. Long-duration spaceflight, new radiotherapeutic procedures and enhanced levels of radon, and other naturally-occurring alpha particle emitters, have all increased concern and stimulated interest recently within the radiological protection and radiobiological communities. Significant data concerning the long-term effects of low levels of heavy ions on mammalian systems are correspondingly scarce, leading to increased emphasis on modelling all aspects of the radiation-organism interaction. Contemporary radiation protection procedures reflect the need for a more fundamental understanding of the mechanisms responsible for the biological actions of such radiations. Major deficiencies exist in the current recommendations for assessment of relative effectiveness, the enhanced severity of the biological consequences instigated by heavy ions, over conventional sparsely ionizing radiations. In an attempt to remedy some of the inadequate concepts and assumptions presently employed and, simultaneously, to gain insight into the fundamental mechanisms behind the notion of radiation quality, a series of algorithms have been developed and executed as computer code, to evaluate the biological effectiveness of heavy ion radiation ''tracks'' according to a number of criteria. These include consideration of the spatial characteristics of physical energy deposition in idealised cellular structures (finite particle range, radial extension of tracks via δ-ray emission) and the likelihood of induction and mis-repair of severe molecular lesions (double-strand breaks, multiply-damaged sites). (author)

  11. Genomic instability and radiation effects

    International Nuclear Information System (INIS)

    Christian Streffer

    2007-01-01

    Complete text of publication follows. Cancer, genetic mutations and developmental abnormalities are apparently associated with an increased genomic instability. Such phenomena have been frequently shown in human cancer cells in vitro and in situ. It is also well-known that individuals with a genetic predisposition for cancer proneness, such as ataxia telangiectesia, Fanconi anaemia etc. demonstrate a general high genomic instability e.g. in peripheral lymphocytes before a cancer has developed. Analogous data have been found in mice which develop a specific congenital malformation which has a genetic background. Under these aspects it is of high interest that ionising radiation can increase the genomic instability of mammalian cells after exposures in vitro an in vivo. This phenomenon is expressed 20 to 40 cell cycles after the exposure e.g. by de novo chromosomal aberrations. Such effects have been observed with high and low LET radiation, high LET radiation is more efficient. With low LET radiation a good dose response is observed in the dose range 0.2 to 2.0 Gy, Recently it has been reported that senescence and genomic instability was induced in human fibroblasts after 1 mGy carbon ions (1 in 18 cells are hit), apparently bystander effects also occurred under these conditions. The instability has been shown with DNA damage, chromosomal aberrations, gene mutation and cell death. It is also transferred to the next generation of mice with respect to gene mutations, chromosomal aberrations and congenital malformations. Several mechanisms have been discussed. The involvement of telomeres has gained interest. Genomic instability seems to be induced by a general lesion to the whole genome. The transmission of one chromosome from an irradiated cell to an non-irradiated cell leads to genomic instability in the untreated cells. Genomic instability increases mutation rates in the affected cells in general. As radiation late effects (cancer, gene mutations and congenital

  12. Notes on radiation effects on materials

    International Nuclear Information System (INIS)

    Anno, J.N.

    1984-01-01

    The effects of radiation from nuclear reactions on various classes of materials are examined in an introductory textbook for students of nuclear engineering. Topics discussed include the units and general scale of radiation damage, fundamental interactions of neutrons and gamma rays with materials, transient radiation effects on electrical components, radiation effects on organic materials and on steels, nuclear fission effects, surface effects of nuclear radiations, radiation effects on biological material, and neutron and gamma-ray dosimetry. Graphs, diagrams, tables of numerical data, and problems for each chapter are provided. 122 references

  13. Thermal effects in radiation processing

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1985-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The csub(p) of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation. (author)

  14. Thermal effects in radiation processing

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1984-01-01

    The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The specific heat of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation

  15. Health effects of radiation and the implications for radiation safety

    International Nuclear Information System (INIS)

    Gonzalez, A.J.; Anderer, J.

    1991-01-01

    In this Paper two elements of a multiphase analysis of radiation exposures in the living environment - the human health effects of ionizing radiation and the implications for radiation safety policy and practices - are presented. Part 1 draws together the current state of scientific knowledge and insight about the human health effects of radiation, describing these in terms of known cause-related deterministic effects and of the estimated incidence of stochastic effects as defined by biostatistics and biological models. The 1988 UNSCEAR report provides an authoritative basis for such an examination. Part 2 explores some of the major implications that the state-of-the-art of radiation biology has - or should have - for radiation safety policy and practices. (author)

  16. Effect of radioactive isotope 32P upon alpha amylase activity and glucose concentration in chickens

    International Nuclear Information System (INIS)

    Kraljevic, P.; Emanovic, D.; Simpraga, M.; Nejedli, S.; Stojevic, Z.

    1996-01-01

    An attempt has been made to investigate whether alpha amylase activity and glucose concentration in blood plasma can serve as the help in establishing on early diagnosis of organic or functional damage caused by ionizing radiation in chickens. Fifty day old hybrid chickens of heavy 'Jata' breeds of both sexes, were treated by 32 P administered intramusculary as sodium orthophosphate in a single dose of 333 MBq per kilogram of body weight. Blood samples was taken from the wing vein on day 1, 3, 5, 7 and 10 after administration of 32 P. Alpha amylase activity and glucose concentration were determined spectrophotometrically using kits produced by 'Radonja', Sisak. Alpha amylase activity was decreased and glucose concentration was increased during investigated period. Yet, the further investigations are needed to find out whether these two parameters can be used for early diagnosis of injury in chicken organism by ionizing radiation. (author)

  17. Alpha amylase and Alpha glucosidase inhibitory effects of aqueous stem extract of Salacia oblonga and its GC-MS analysis

    Directory of Open Access Journals (Sweden)

    Gladis Raja Malar Chelladurai

    2018-05-01

    Full Text Available ABSTRACT Our present investigation deals with the phytochemical screening, estimation of total flavonoids, terpenoids and tannin contents to evaluate the anti-diabetic activities of Salacia oblonga stem followed by GC-MS analysis. It explores the natural compounds and the potential α-amylase and α-glucosidase inhibitory actions of stem extracts. The aqueous stem extract was selected from other extracts (ethanol, acetone, petroleum ether and chloroform for the in vitro study of anti-diabetic activity by alpha amylase and alpha glucosidase inhibitory assays. The stem extract was also analyzed by gas chromatography mass spectrometry to identify the natural chemical components. Phytochemical analysis of aqueous stem extract showed major classes of secondary metabolites such as phenols, flavonoids, alkaloids, terpenoids, tannins, saponins. The total flavonoid, terpenoid, and tannin contents were quantified as 19.82±0.06 mg QE/g, 96.2±0.20 mg/g and 11.25±0.03 mg TAE/g respectively. The percentage inhibition of assays showed maximum inhibitory effects (59.46±0.04% and 68.51±0.01% at a concentration of 100 mg/mL. The IC50 values of stem extract was found to be 73.56 mg/mL and 80.90 mg/mL for alpha amylase and alpha glucosidase inhibition. Fifteen chemical constituents were found by GC-MS analysis. This study suggest the aqueous stem extract of Salacia oblonga might be considered as potential source of bio active constituents with excellent antidiabetic activity.

  18. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity.

    Science.gov (United States)

    Kudryasheva, N S; Rozhko, T V

    2015-04-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1--absence of effects (stress recognition), 2--activation (adaptive response), and 3--inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Effects of ionizing radiation on extracellular matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, F. [School of Physics, University of Exeter, Exeter EX44QL (United Kingdom)], E-mail: f.mohamed@ex.ac.uk; Bradley, D.A. [Department of Physics, University of Surrey, Guildford GU72XH (United Kingdom); Winlove, C.P. [School of Physics, University of Exeter, Exeter EX44QL (United Kingdom)

    2007-09-21

    The extracellular matrix is a ubiquitous and important component of tissues. We investigated the effects of ionizing radiation on the physical properties of its principal macromolecular components, pericardial collagen, ligament elastin and hyaluronan, a representative glycosaminoglycan. Samples were exposed to X-rays from an electron linear accelerator in the range of 10-100 Gy to cover the range of irradiation exposure during radiotherapy. A uniaxial mechanical testing protocol was used to characterize the fibrous proteins. For pericardial tissue the major change was an increase in the elastic modulus in the toe region of the curve ({<=}20% strain), from 23{+-}18 kPa for controls to 57{+-}22 kPa at a dose of 10 Gy (p=0.01, {alpha}=0.05). At larger strain ({>=}20% strain), the elastic modulus in the linear region decreased from 1.92{+-}0.70 MPa for control pericardium tissue to 1.31{+-}0.56 MPa (p=0.01, {alpha}=0.05) for 10 Gy X-irradiated sample. Similar observations have been made previously on tendon collagen at larger strains. For elastin, the stress-strain relationship was linear up to 30% strain, but the elastic modulus decreased significantly with irradiation (controls 626{+-}65 kPa, irradiated 474{+-}121 kPa (p=0.02, {alpha}=0.05), at 10 Gy X-irradiation). The results suggest that for collagen the primary effect of irradiation is generation of additional cross-links, while for elastin chain scissions are important. The viscosity of HA (at 1.25% w/v and 0.125% w/v) was measured by both cone and plate and capillary viscometry, the former providing measurement at uniform shear rate and the latter providing a more sensitive indication of changes at low viscosity. Both techniques revealed a dose-dependent reduction in viscosity (from 3400{+-}194 cP for controls to 1500{+-}88 cP at a shear rate of 2 s{sup -1} and dose of 75 Gy), again suggesting depolymerization.

  20. Research on radiation effect and radiation protection at JAEA

    International Nuclear Information System (INIS)

    Saito, Kimiaki

    2007-01-01

    Researches on radiation effect and radiation protection at JAEA have been carried out in different sections. In recent years, the organizations were rearranged to attain better research circumstances, and new research programs started. At present, radiation effect studies focus on radiation effect mechanisms at atomic, molecular and cellular levels including simulation studies, and protection studies focus on dosimetry for conditions difficult to cover with currently used methods and data as well as the related basic studies. The outlines of the whole studies and also some descriptions on selected subjects will be given in this paper. (author)

  1. Health effect of exposure to internally deposited alpha-emitting radionuclides

    International Nuclear Information System (INIS)

    Iwata, Shiro

    1989-01-01

    The health effect of exposure on human population to internally deposited alpha-emitting radionuclides and their decay products has been considered as most hazardous radiation effect. However, the harmful late effects by the intake of radioactive nuclides are not definite in the epidemiological and clinical viewpoint. Only two cases, radium and thorium, have since long been noted for their deletrious effects to man. As the former, it has been first reported that dial workers in USA using 226 Ra can suffer from 'radiumjaw' which is a cancer of the bone of jaws. Another radium isotope, 224 Ra, was used for a medical reason as therapy against turberculosis of bone to German children during the years 1946∼1950, and has given rise to bone cancer. As the latter, Thorotrast (the commercial name of a colloidal thorium dioxide preparation), introduced for angiography in 1929 and utilized until about 1950, was found to cause malignant hepatic tumors, liver cirrhosis and blood diseases such as some kinds of leukemia and anemia. In Japan, the former cases have seldom found though, the latter cases are assumed over 1000. Especially, Thorotrast administered war-wounded ex-servicemen in World War II have been beyond 300 persons. The epidemiological and clinico-pathological studies have been demonstrated by the research Group on Biological Effect of Thorium in Special Project Research on Energy, Japan, as a fundamental study of the safe treatment of nuclear fuel materials. The resultant data of the study and risk evaluation of liver cancer for Japanese Thorotrast administered patients are reviewed related to that of another alpha-emitting radionuclides. (author)

  2. Divergent effects of tumor necrosis factor alpha on apoptosis of human neutrophils

    NARCIS (Netherlands)

    van den Berg, J. M.; Weyer, S.; Weening, J. J.; Roos, D.; Kuijpers, T. W.

    2001-01-01

    Apoptosis of neutrophils is a key mechanism to control the intensity of the acute inflammatory response. Previously, the cytokine tumor necrosis factor alpha (TNF-alpha) was reported by some to have pro-apoptotic and by others to have antiapoptotic effects on neutrophils. The aim of this study was

  3. Specific spheres of application of ionising radiation effects, some realized results and comparative advantages

    International Nuclear Information System (INIS)

    Benderac, R.

    2007-01-01

    The papers discusses some results of ionizing radiation effects in realization of non-destructive methods, achieved progress from the aspect of innovation, comparative results with previously used methods, etc. A review is given of methods based on alpha-radiography, auto-alpha radiography, beta-radiography, X-ray-fluorescent analysis, X- and gamma radiography, and photos of specific samples of neutron radiography [sr

  4. Diagnostics of red-shifted H-alpha line emission from a C-class flare with full non-LTE radiative and hydrodynamic approach

    Science.gov (United States)

    Druett, M. K.; Zharkova, V. V.; Scullion, E.; Zharkov, S.; Matthews, S. A.

    2016-12-01

    We analyse H-alpha line profiles with strong redshifts during the C1.8 flare on 1st July 2012 obtained from the Swedish Solar Telescope (SST) closely resembling the previous observations (Wuelser and Marti, 1989). The flare has a magnetic field configuration with two levels of loop structures. The kernels with red shifts are observed in one of the H-alpha ribbons in the south-west location formed after the main impulse recorded in the north-east. The locations of H-alpha kernels with red shifts reveal close temporal and spatial correlation with weaker HXR signatures and coincide with the locations of coronal jets observed with AIA/SDO. For interpretation we apply a revised 1D hydrodynamic and non-LTE (NLTE) radiative model for 5 level plus continuum model hydrogen atom (Druett & Zharkova, 2016) considering radiative, thermal and non-thermal excitation and ionisation by beam electrons with the updated beam densities (Zharkova & Dobranskis, 2016) and analytical excitation/ionisation rates (Zharkova& Kobylinskijj, 1993). We find the simultaneous solutions of steady state and radiative transfer equations in all optically-thick lines and continua. The electron and ion temperatures, ambient density and macrovelocity of the ambient plasma are derived from a 1D hydrodynamic model with initial condition of the pre-flaring photosphere for the two fluid ambient plasma heated by beam electrons (Zharkova & Zharkov, 2007). We simulate distributions over precipitation depth of ionisation and departure coefficients for all the hydrogen atom transitions including the deviation of ionisation from Saha equation affected by non-thermal electron beams. We show that in the very first seconds after the beam onset Balmer line profiles are sensitive to the effect of beam electrons. The combination of the additional ionisation caused by beam electrons leading to a very strong Stark effect in Balmer lines with the hydrodynamic heating and formation of a low temperature shock in the

  5. Therapeutic effect of anti-feline TNF-alpha monoclonal antibody for feline infectious peritonitis.

    Science.gov (United States)

    Doki, Tomoyoshi; Takano, Tomomi; Kawagoe, Kohei; Kito, Akihiko; Hohdatsu, Tsutomu

    2016-02-01

    Feline infectious peritonitis virus (FIPV) replication in macrophages/monocytes induced tumor necrosis factor (TNF)-alpha production, and that the TNF-alpha produced was involved in aggravating the pathology of FIP. We previously reported the preparation of a feline TNF-alpha (fTNF-alpha)-neutralizing mouse monoclonal antibody (anti-fTNF-alpha mAb). This anti-fTNF-alpha mAb 2-4 was confirmed to inhibit the following fTNF-alpha-induced conditions in vitro. In the present study, we investigated whether mAb 2-4 improved the FIP symptoms and survival rate of experimentally FIPV-inoculated SPF cats. Progression to FIP was prevented in 2 out of 3 cats treated with mAb 2-4, whereas all 3 cats developed FIP in the placebo control group. Plasma alpha1-glycoprotein and vascular endothelial growth factor levels were improved by the administration of mAb 2-4, and the peripheral lymphocyte count also recovered. These results strongly suggested that the anti-fTNF-alpha antibody is effective for the treatment of FIP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Efficacy of Topical Alpha Ointment (Containing Natural Henna Compared to Topical Hydrocortisone (1% in the Healing of Radiation-Induced Dermatitis in Patients with Breast Cancer: A Randomized Controlled Clinical Trial

    Directory of Open Access Journals (Sweden)

    Mansour Ansari

    2013-12-01

    Full Text Available Background: This two-arm, randomized clinical study aimed to compare efficacy between topical Alpha ointment and topical hydrocortisone cream (1% in the healing of radiation-induced dermatitis in breast cancer patients. Methods: The inclusion criteria comprised newly pathologically proven, locally advanced breast cancer (treated with modified radical mastectomy followed by sequential adjuvant treatments, including chest wall radiotherapy [45-50.4 Gy] and grade 2 and/or 3 chest wall dermatitis. The exclusion criteria were comprised of any underlying disease or medications interfering with the wound healing process, previous history of chest wall radiotherapy, and concurrent use of chemotherapy. Sixty eligible patients were randomly assigned to use either topical Alpha ointment (study arm, n=30 or topical hydrocortisone cream (1% (control arm, n=30 immediately after receiving a total dose of 45-50 Gy chest wall radiotherapy. Results: The mean radiation dose was 49.1 Gy in the control arm and 48.8 Gy in the study arm. The mean dermatitis area was 13.54 cm2 in the control arm and 17.02 cm2 in the study arm. Topical Alpha ointment was more effective on the healing of radiation-induced dermatitis than was topical hydrocortisone cream (1% (P=0.001. This effect was significant in the second week (P=0.007. In addition, Alpha ointment decreased the patients’ complaints such as pain (P<0.001, pruritus (P=0.009, and discharge (P=0.010 effectively and meaningfully. Conclusion: Topical Alpha ointment was more effective on the healing of radiation-induced dermatitis than was topical hydrocortisone cream (1% in our patients with breast cancer. Trial Registration Numbers: IRCT201206099979N1 ACTRN12612000837820

  7. Efficacy of topical alpha ointment (containing natural henna) compared to topical hydrocortisone (1%) in the healing of radiation-induced dermatitis in patients with breast cancer: a randomized controlled clinical trial.

    Science.gov (United States)

    Ansari, Mansour; Farzin, Dehsara; Mosalaei, Ahmad; Omidvari, Shapour; Ahmadloo, Niloofar; Mohammadianpanah, Mohammad

    2013-12-01

    This two-arm, randomized clinical study aimed to compare efficacy between topical Alpha ointment and topical hydrocortisone cream (1%) in the healing of radiation-induced dermatitis in breast cancer patients. The inclusion criteria comprised newly pathologically proven, locally advanced breast cancer (treated with modified radical mastectomy followed by sequential adjuvant treatments, including chest wall radiotherapy [45-50.4 Gy]) and grade 2 and/or 3 chest wall dermatitis. The exclusion criteria were comprised of any underlying disease or medications interfering with the wound healing process, previous history of chest wall radiotherapy, and concurrent use of chemotherapy. Sixty eligible patients were randomly assigned to use either topical Alpha ointment (study arm, n=30) or topical hydrocortisone cream (1%) (control arm, n=30) immediately after receiving a total dose of 45-50 Gy chest wall radiotherapy. The mean radiation dose was 49.1 Gy in the control arm and 48.8 Gy in the study arm. The mean dermatitis area was 13.54 cm(2) in the control arm and 17.02 cm(2) in the study arm. Topical Alpha ointment was more effective on the healing of radiation-induced dermatitis than was topical hydrocortisone cream (1%) (P=0.001). This effect was significant in the second week (P=0.007). In addition, Alpha ointment decreased the patients' complaints such as pain (P<0.001), pruritus (P=0.009), and discharge (P=0.010) effectively and meaningfully. Topical Alpha ointment was more effective on the healing of radiation-induced dermatitis than was topical hydrocortisone cream (1%) in our patients with breast cancer. IRCT201206099979N1, ACTRN12612000837820.

  8. Protective effect of poly ({alpha}-L-glutamate) against UV and {gamma}-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, Masakazu E-mail: mfuruta@riast.osakafu-u.ac.jp; Huy, Nguyen Quang; Tsuchiya, Akihito; Nakatsuka, Hiroshige; Hayashi, Toshio

    2004-10-01

    We occasionally found that poly ({alpha}-L-glutamate) showed a superior protective effect on enzymes against UV and {sup 60}Co-{gamma} irradiation. We selected papain and {alpha}-amylase as a model enzyme and irradiated the aqueous solution (10 mg/ml) of each enzyme with UV and {sup 60}Co-{gamma} rays in the presence of poly ({alpha}-L-glutamate) ({alpha}-PGA), poly (glucosyl oxyethyl methacrylate (GEMA)), and glucose (1.25% w/v each). The mixture of the three compounds has a significant protective effect on the activity of papain solution showing 40% of remaining activity twice as much as the control containing no additive at the dose of 15 kGy. Among them, {alpha}-PGA showed the highest protecting effect on the both papain and {alpha}-amylase even after 10-kGy irradiation at which 50% of the activity was retained. {alpha}-PGA also showed significant protective activity on {alpha}-amylase against UV both in solution and under dried state.

  9. Effect of tumor necrosis factor-alpha infusion on the incretin effect in healthy volunteers

    DEFF Research Database (Denmark)

    Nielsen, Signe Tellerup; Lehrskov-Schmidt, Louise; Krogh-Madsen, Rikke

    2013-01-01

    Type 2 diabetes mellitus (T2DM) is associated with peripheral insulin resistance, impaired incretin effect, and increased plasma levels of tumor necrosis factor-alpha (TNF-α). Whereas TNF-α infusion at a dose that induces systemic inflammation in healthy volunteers has been demonstrated to induce...

  10. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    Unknown

    1999-01-01

    The US Department of Energy (DOE) has expressed a need for an on-line, real-time instrument for assaying alpha-emitting radionuclides (uranium and the transuranics) in effluent waters leaving DOE sites to ensure compliance with regulatory limits. Due to the short range of alpha particles in water (approximately40 Im), it is necessary now to intermittently collect samples of water and send them to a central laboratory for analysis. A lengthy and costly procedure is used to separate and measure the radionuclides from each sample. Large variations in radionuclide concentrations in the water may go undetected due to the sporadic sampling. Even when detected, the reading may not be representative of the actual stream concentration. To address these issues, the Advanced Technologies Group of Thermo Power Corporation (a Thermo Electron company) is developing a real-time, field-deployable alpha monitor based on a solid-state silicon wafer semiconductor (US Patent 5,652,013 and pending, assigned to the US Department of Energy). The Thermo Water Alpha Monitor will serve to monitor effluent water streams (Subsurface Contaminants Focus Area) and will be suitable for process control of remediation as well as decontamination and decommissioning (D and D) operations, such as monitoring scrubber or rinse water radioactivity levels (Mixed Waste, Plutonium, and D and D Focus Area). It would be applicable for assaying other liquids, such as oil, or solids after proper preconditioning. Rapid isotopic alpha air monitoring is also possible using this technology. This report details the program's accomplishments to date. Most significantly, the Alpha Monitoring Instrument was successfully field demonstrated on water 100X below the Environmental Protection Agency's proposed safe drinking water limit--down to under 1 pCi/1. During the Field Test, the Alpha Monitoring Instrument successfully analyzed isotopic uranium levels on a total of five different surface water, process water, and

  11. Alpha Blockers

    Science.gov (United States)

    ... quickly, but their effects last only a few hours. Long-acting medications take longer to work, but their effects last longer. Which alpha blocker is best for you depends on your health and the condition being treated. Alpha blockers are ...

  12. Genetic and somatic effects of ionizing radiation

    International Nuclear Information System (INIS)

    1986-01-01

    This is the ninth substantive report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) to the General Assembly. This report contains reviews on three special topics in the field of biological effects of ionizing radiation that are among those presently under consideration by the Committee: genetic effects of radiation, dose-response relationships for radiation-induced cancer and biological effects of pre-natal irradiation

  13. Caffeine-mediated release of alpha-radiation-induced G2 arrest increases the yield of chromosome aberrations

    International Nuclear Information System (INIS)

    Luecke-Huhle, C.; Hieber, L.; Wegner, R.D.

    1983-01-01

    Severe and partly irreversible G2 arrest caused by americium-241 alpha-particles in Chinese hamster V79 cells acted as a competing process to the yield of detectable aberrant mitoses at metaphase. With increasing dose of alpha-radiation an increasing fraction of cells was irreversibly arrested in G2 with the consequence of interphase death before the first post-irradiation mitosis. This irreversible G2 arrest (demonstrated by flow cytofluorometry and mitotic indices) could be overcome by adding caffeine 8 hours after irradiation, the time point of maximum G2 arrest (80-90 per cent of all cells). Within 3.5 hours the number of aberrant mitoses increased by this treatment from 54 to 96 per cent and from 65 to 99.9 per cent for doses of 1.75 and 4.38 Gy of alpha-particles, respectively. The aberration frequency per mitotic cell, scored as chromatid and isochromatid breaks, rings, interchanges and dicentrics increased by a factor of about 3 after releasing G2 arrested cells. The frequency distribution of aberrations per cell revealed that, after 4.38 Gy, 58 per cent of the formerly G2-arrested cells had more than five aberrations per cell compared to only 8 per cent without the interaction of caffeine. (author)

  14. Effects of tamsulosin metabolites at alpha-1 adrenoceptor subtypes

    NARCIS (Netherlands)

    Taguchi, K.; Saitoh, M.; Sato, S.; Asano, M.; Michel, M. C.

    1997-01-01

    We have investigated the affinity and selectivity of tamsulosin and its metabolites, M1, M2, M3, M4 and AM1, at the tissue and the cloned alpha-1 adrenoceptor subtypes in the radioligand binding and the functional studies. In the radioligand binding studies, the compounds competed for [3H]prazosin

  15. Natural alpha recoil particle radiation and ionizing radiation sensitivities in quartz detected with EPR: implications for geochronometry

    International Nuclear Information System (INIS)

    Rink, W.J.; Odom, A.L.

    1991-01-01

    The electron paramagnetic resonance EPR signals in granitic quartz samples of known age are studied. Time-integrated alpha recoil activity and EPR signal intensity are more significantly correlated than sample age and EPR signal intensity. Neutron activation analysis for internal uranium and thorium in quartz are reported. Natural germanium EPR signals are observed in pegmatitic quartz samples and one granitic quartz. Pegmatitic quartz exhibits germanium EPR center growth competing strongly with E' center growth, apparently leading to depleted natural concentrations of E' centers. Calculations of lattice vacancy accumulation associated with alpha recoil damage are presented and compared with concentrations of paramagnetic oxygen vacancies in the quartz. Based on the results reported, the potential and problems associated with dating quartz are discussed, relating both to accumulated lattice damage and the additive dose methods. (author)

  16. Effect of dietary alpha-tocopherol supplementation and gamma-irradiation on alpha-tocopherol retention and lipid oxidation in cooked minced chicken

    International Nuclear Information System (INIS)

    Galvin, K.; Morrissey, P.A.; Buckley, D.J.

    1998-01-01

    The effects of dietary alpha-tocopherol supplementation and gamma-irradiation on alpha-tocopherol retention and lipid oxidation in cooked minced chicken during refrigerated storage were studied. Minced breast and thigh meat from broilers fed diets supplemented with 100, 200 or 400 mg alpha-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0 kGy. Cooked irradiated and unirradiated meat was stored at 4 degrees C for 5 days. alpha-Tocopherol concentrations increased with increasing dietary supplementation. Concentrations decreased during storage, but retention was not affected by irradiation. Lipid stability was determined by measuring the formation of thiobarbituric acid-reacting substances (TBARS) and cholesterol oxidation products (COPs) during storage. TBARS and COPs increased during storage and were reduced by increasing levels of dietary alpha-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg alpha-tocopheryl acetate/kg feed. Irradiation tended to increase COPs during storage, although no consistent effects were observed. In general supplementation with over 400 mg alpha-tocopheryl acetate/kg feed may be required to control cholesterol oxidation in minced chicken. The results suggest that, overall, irradiation had little effect on lipid stability in alpha-tocopherol-supplemented meat following cooking and storage

  17. A photon-transparent alpha-radiation source, its method of manufacture and applications thereof

    International Nuclear Information System (INIS)

    Charuau, Jean; Cimetiere, Claudette; Desroches, Jean; Dupoux, Jean.

    1974-01-01

    The source comprises, in succession, a glass substratum, an alpha-emitting thin layer placed on said substratum and fixed thereto, and an inert coating constituted by a layer of pyrex glass. That can be applied to the measurement of fluorescent deposits of small thickness for aerosols determination [fr

  18. DEVELOPMENT OF AN ON-LINE, REAL-TIME ALPHA RADIATION MEASURING INSTRUMENT FOR LIQUID STREAMS

    International Nuclear Information System (INIS)

    Unknown

    1999-01-01

    Thermo Power Corporation has proven the technical viability of an on-line, real-time alpha radionuclide instrument for aqueous sample analysis through laboratory and initial field tests of the instrument. The instrument has been shown to be isotonically sensitive to extremely low (ten parts per trillion, or femto Curies per liter) levels of a broad range of radioisotopes. Performance enhancement and other scaling data obtained during the course of this investigation have shown that on-line, real-time operation is possible, with a sub 30-minute response time analyzing 20 ppb (30 pCi/1) natural uranium. Now that these initial field tests in Oak Ridge, Tennessee have been successfully completed, Thermo Power plans to conduct comprehensive field tests of the instrument. The purpose of these endurance tests will be to determine the endurance characteristics of the Thermo Alpha Monitor for Water when it is used by non-Thermo Power personnel in a series of one or more extended field tests. Such endurance testing is the vital next step towards the commercialization of the Alpha Monitor. Subsequently, it will be possible to provide the DOE with an instrument that has the capability of obtaining rapid feedback about the concentrations of alpha-emitting isotope contamination in effluent water streams (Subsurface Contaminants Focus Area). It will also be useful for process control of remediation and D and D operations such as monitoring scrubber/rinse water radioactivity levels (Mixed Waste, Plutonium and D and D Focus Areas)

  19. Effect of Ionizing Radiation on Luminous Bacteria Cells

    International Nuclear Information System (INIS)

    Kudryasheva, N.; Rozhko, T.; Alexandrova, M.; Vasyunkina, E.; Arkhipova, V.

    2011-01-01

    Marine luminous bacteria were used to monitor toxicity of alpha- (Am-241, U-235+238) and beta- (tritium) radionuclide solutions. Increase or inhibition of bacterial luminescence was observed under exposure to radionuclides. Radiation toxicity of Am and chemical toxicity of U were demonstrated. Effects of U were similar to those of stable heavy metals: sensitivity was about 10-5 M. Sensitivity of the bacteria to Am-241 was 300 Bq/L (10 -11 M). Inhibition of bacterial growth was observed under exposure to Am-241 and tritium. Role of peroxides and electron transfer processes in the effects of radionuclides on luminous bacteria is discussed.

  20. The Alpha value decrease when the annual individual effective dose decreases?

    International Nuclear Information System (INIS)

    Sordi, Gian M.; Marchiusi, Thiago; Sousa, Jefferson de J.

    2008-01-01

    A recent IAEA publication tells that a few entities took different alpha values for maxima individual doses. Beyond to disregard the international agencies, that recommend only one alpha value for each country, the alpha values decreases when the individual doses decreases and the practice happens exactly the conversely as we will show in this paper. We will prove that the alpha value increase when the maximum individual doses decreases in a four different manner. The first one we call the theoretical conception and it is linked to the emergent of the ALARA policy and to the purpose that led to the 3/10 of the annual limits, for to decrease the individual doses as a first resort and a 1/10 as a last resort. The second prove will be based in a small mine example used in the ICRP publication number 55 concerning to the optimization and the quantitative decision-aiding techniques in radiological protection where we will determine the alpha value ranges in which each radiological protection options becomes the analytical solution. The third prove will be based in the determination of the optimized thickness example of a plane shielding for a radiation source exposed in the ICRP publication number 37. We will use, also, the numerical example provided there. Eventually, as four prove we will show that the alpha value dos not only increases with the maximum individual dose decrease, but also, with the shielding geometry. (author)

  1. Different small, acid-soluble proteins of the alpha/beta type have interchangeable roles in the heat and UV radiation resistance of Bacillus subtilis spores

    International Nuclear Information System (INIS)

    Mason, J.M.; Setlow, P.

    1987-01-01

    Spores of Bacillus subtilis strains which carry deletion mutations in one gene (sspA) or two genes (sspA and sspB) which code for major alpha/beta-type small, acid-soluble spore proteins (SASP) are known to be much more sensitive to heat and UV radiation than wild-type spores. This heat- and UV-sensitive phenotype was cured completely or in part by introduction into these mutant strains of one or more copies of the sspA or sspB genes themselves; multiple copies of the B. subtilis sspD gene, which codes for a minor alpha/beta-type SASP; or multiple copies of the SASP-C gene, which codes for a major alpha/beta-type SASP of Bacillus megaterium. These findings suggest that alpha/beta-type SASP play interchangeable roles in the heat and UV radiation resistance of bacterial spores

  2. Prostaglandin production by melanocytic cells and the effect of alpha-melanocyte stimulating hormone.

    Science.gov (United States)

    Nicolaou, Anna; Estdale, Sian E; Tsatmali, Marina; Herrero, Daniel Pascual; Thody, Anthony J

    2004-07-16

    Prostaglandins are potent mediators of the inflammatory response and are also involved in cancer development. In this study, we show that human melanocytes and FM55 melanoma cells express cyclooxygenase-1 and -2 (COX-1 and -2) and thus have the capability to produce prostaglandins. The FM55 cells produced predominantly PGE2 and PGF2alpha, whereas the HaCaT keratinocyte cell line produced mainly PGE2. The anti-inflammatory peptide, alpha-melanocyte stimulating hormone (alpha-MSH), reduced prostaglandin production in FM55 and HaCaT cells and reversed the effect of the pro-inflammatory cytokine TNF-alpha in the former. These results indicate that melanocytes produce prostaglandins and that alpha-MSH, by inhibiting this response, may play an important role in regulating inflammatory responses in the skin.

  3. Ionising radiation - physical and biological effects

    International Nuclear Information System (INIS)

    Holter, Oe.; Ingebretsen, F.; Parr, H.

    1979-01-01

    The physics of ionising radiation is briefly presented. The effects of ionising radiation on biological cells, cell repair and radiosensitivity are briefly treated, where after the effects on man and mammals are discussed and related to radiation doses. Dose limits are briefly discussed. The genetic effects are discussed separately. Radioecology is also briefly treated and a table of radionuclides deriving from reactors, and their radiation is given. (JIW)

  4. Radiation effects on microelectronics in space

    International Nuclear Information System (INIS)

    Srour, J.R.; McGarrity, J.M.

    1988-01-01

    The basic mechanisms of space radiation effects on microelectronics are reviewed in this paper. Topics discussed include the effects of displacement damage and ionizing radiation on devices and circuits, single event phenomena, dose enhancement, radiation effects on optoelectronic devices and passive components, hardening approaches, and simulation of the space radiation environment. A summary is presented of damage mechanisms that can cause temporary or permanent failure of devices and circuits operating in space

  5. Effect of radiation in radiotherapy

    International Nuclear Information System (INIS)

    Hirata, Hideki; Fujibuchi, Toshio; Saito, Tsutomu

    2013-01-01

    The title subject is easily explained for the deterministic effect, secondary cancer formation and case reports of accidental exposure at radiotherapy. For the deterministic effect, the dose-effect relationship is sigmoidal in normal and cancer tissues, and the more separated are their curves, the more favorable is the radiotherapy. TD 5/5 is the tolerable dose to yield <5% of irreversible radiation injury to the normal tissue within 5 years after the therapy and is generally dose-limiting. The curves are of various shapes depending on the tissue composition that its functional subunit (FSU) is parallel like lobules of the liver, or in series like neuron. Symptoms appear complicated on these factors. Recent development of CT-based therapeutic planning has made it possible to analyze the partial tissue volume to be irradiated and its absorbed dose by the relationship (dose volume histogram, DVH) between the electron density vs CT value regardless to anatomy. The normal tissue complication probability is a model composed from the physical DVH and biological factors of FSU composition and cellular radiation susceptibility, and is a measure of the irreversible late effect manifested in normal tissues. Epidemiology has shown the increased risk of secondary cancer formation by radiotherapy. Children are highly susceptible to this, and in adults undergoing the therapy of a certain cancer, it is known that the risk of radiation carcinogenesis is increased in the particular tissue. There are presented such case reports of accidental excessive exposure at radiotherapy as caused by an inappropriate use of detector, partial loss of data in a therapeutic planning device, reading of reversed MRI image, and too much repeated use of the old-type electric portal imaging device. (T.T.)

  6. Radiation Effects in Nuclear Ceramics

    Directory of Open Access Journals (Sweden)

    L. Thomé

    2012-01-01

    Full Text Available Due to outstanding physicochemical properties, ceramics are key engineering materials in many industrial domains. The evaluation of the damage created in ceramics employed in radiative media is a challenging problem for electronic, space, and nuclear industries. In this latter field, ceramics can be used as immobilization forms for radioactive wastes, inert fuel matrices for actinide transmutation, cladding materials for gas-cooled fission reactors, and structural components for fusion reactors. Information on the radiation stability of nuclear materials may be obtained by simulating the different types of interactions involved during the slowing down of energetic particles with ion beams delivered by various types of accelerators. This paper presents a review of the radiation effects occurring in nuclear ceramics, with an emphasis on recent results concerning the damage accumulation processes. Energetic ions in the KeV-GeV range are used to explore the nuclear collision (at low energy and electronic excitation (at high energy regimes. The recovery by electronic excitation of the damage created by ballistic collisions (SHIBIEC process is also addressed.

  7. Rederivation of the alpha effect in terms of the magnetic fluctuation spectrum

    International Nuclear Information System (INIS)

    Keinigs, R.K.; Gerwin, R.A.

    1982-08-01

    We demonstrate that the alpha effect can be expressed in terms of the integrated current helicity spectrum of the turbulence. This is a much more convenient form than that obtained using a kinematic velocity field description

  8. Radiation protection in radionuclide investigations

    International Nuclear Information System (INIS)

    Taylor, D.M.

    1985-01-01

    The subject is covered in sections: introduction; radiation and radioactivity; alpha particles; beta particles; neutrons; electromagnetic radiation; units of radioactivity and radiation; biological effects of radiation; the philosophy of radiation protection (ALARA principle); practical aspects of radiation protection; work with unsealed radiation sources; radionuclide studies in experimental animals; radiation safety during clinical investigations; legislative control of radiation work; radioactive waste disposal; emergency procedures; conclusion. (U.K.)

  9. Minidosimetry of alpha-radiation from 239-Pu in the skeleton

    International Nuclear Information System (INIS)

    Polig, E.

    1980-01-01

    A novel technique for evaluating alpha-autoradiograms of the skeleton was developed and applied. The method involves scanning the alpha-track distribution on cellulose-nitrate detector foils and determination of tissue structure from Alizarin-stained bone sections (150 μm) by means of a computer controlled microscope photometer. Geometrical alignment between the two samples is preserved during the measuring process. After combining the files containing the track density distribution with the corresponding digitized bone images on a random access storage medium, detailed information concerning the radionuclide distribution on a microscopic scale, dose rates, hit frequencies etc. are extracted by a sequence of FORTRAN-programs. The potential of the method is demonstrated in a study dealing with the distribution of 239-Pu in the lumbar vertebra of adult rats. The measured dose rate distribution is discussed in terms of hit probabilities for cell nuclei and consequences for quantitative tumour models are indicated. (H.K.)

  10. Radioprotection effects of TMG to radical scavenger effect of the mice in radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Yeunhwa; Hasegawa, Takeo; Oshima, Masami [Suzuka Univ. of Medical Science, Suzuka (Japan)] [and others

    2002-07-01

    Now there is many it, and the radiotherapy that is one of cancer therapy is used by single or anticancer drug and combination. A chemical material has been used as radioprotector, but the use is limited conventionally by a serious side effect. Vitamin E derivative[TMG 2- ({alpha} - D-Glucopyranosyl) Methyl-2,5,7,8-Teramethyl -chorman-6-OL] which we are water-soluble, And is the nature material as well for the fetal teratogenicity that I use ICR mouse used for a malformed experiment frequently in this study, and sensibility for radiation is the highest, we studied radiation protection effect of TMG. As a result, as for the fetal malformed incidence, it was admitted that it fell in shifts and changes by administering TMG before radiation exposure. Decrease depression of degradation of a skeletal malformation rate in particular and fetal weight was recognized, and an individual level made radiation protection indication of TMG clear. In addition, that there was radioprotection effect for embryonic death by radiation was made clear by premedication doing TMG equally, and that there was protection effect for radiation exposure in a cell level same as an individual level was proved, and TMG showed the potency that it was it in radioprotector promising in the future. Furthermore, by what we reviewed about congenital defect for radiation, effect for skeletal malformation incidence and sensibility of embryonic cell level in organogenesis, we analyzed mechanism of protection effect of TMG for fetal teratogenicity by radiation experimentally.

  11. Radiation effects on cell membranes

    International Nuclear Information System (INIS)

    Koeteles, G.J.

    1982-01-01

    The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries. (orig.)

  12. Radiation effects on cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Koeteles, G.J.

    1982-11-01

    The recent developments in the field of membrane biology of eukaryotic cells result in revival of relevant radiobiological studies. The spatial relations and chemical nature of membrane components provide rather sensitive targets. Experimental data are presented concerning the effects of relatively low doses of X-irradiation and low concentration of tritiated water (HTO) on various receptor functions - concanavalin A, cationized ferritin, poliovirus - of plasma membranes of animal and human cells which point to early and temporary disturbances of the composite structures and functions of membranes. References are given to the multifold roles of radiationinduced membrane phenomena on the development and regeneration of radiation injuries.

  13. Effect of radiation on food

    Energy Technology Data Exchange (ETDEWEB)

    Sofyan, R [National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre

    1983-07-01

    Research reports on the effect on radiation on food are reviewed. Irradiation processing inhibits the sprouting of vegetables, delays ripening, reduces the number of microorganisms that spoil food, controls patrogenic organisms and parasites found in food, disinfests food of insects, and disinfects spices of microbes. So far there has been no evidence that food irradiaton introduces nutritional or microbiological problems. The FAO/WHO/IAEA expert committee on the wholesomeness of irradiated food recommend the acceptability from a toxicological stand-point of any food commodity irradiated up to an overall average dose of 10 kilograys.

  14. Effect of radiation on food

    International Nuclear Information System (INIS)

    Sofyan, Rochestri

    1983-01-01

    Research reports on the effect on radiation on food are reviewed. Irradiation processing inhibits the sprouting of vegetables, delays ripening, reduces the number of microorganisms that spoil food, controls patrogenic organisms and parasites found in food, disinfests food of insects, and disinfects spices of microbes. So far there has been no evidence that food irradiaton introduces nutritional or microbiological problems. The FAO/WHO/IAEA expert committee on the wholesomeness of irradiated food recommend the acceptability from a toxicological stand-point of any food commodity irradiated up to an overall average dose of 10 kilograys. (RUW)

  15. The work of ICRP Committee 1 on radiation effects

    International Nuclear Information System (INIS)

    Rëhm, W.

    2018-01-01

    Among the four ICRP Committees, Committee 1 deals with the effects of ionizing radiation. For example, this committee considers the risks and mechanisms of induction of cancer and heritable disease; discusses the risks, severity, and mechanisms of induction of tissue/organ damage and developmental defects; and reviews effects of ionizing radiation on non-human biota on a population level. The present paper gives an overview on the recent activities of the committee including the last meetings in Chennai, India, in 2016, and in Paris, France, in 2017. The paper also discusses briefly the focus of the currently active C1 Task Groups on alpha emitters, low-dose and low-dose-rate effects, and detriment calculation methodology

  16. Effects of radiation upon gastrointestinal motility

    Institute of Scientific and Technical Information of China (English)

    Mary F Otterson

    2007-01-01

    Whether due to therapeutic or belligerent exposure, the gastrointestinal effects of irradiation produce symptoms dreaded by a majority of the population. Nausea, vomiting, diarrhea and abdominal cramping are hallmarks of the prodromal phase of radiation sickness, occurring hours to days following radiation exposure. The prodromal phase is distinct from acute radiation sickness in that the absorptive, secretory and anatomic changes associated with radiation damage are not easily identifiable. It is during this phase of radiation sickness that gastrointestinal motility significantly changes. In addition, there is evidence that motor activity of the gut contributes to some of the acute and chronic effects of radiation.

  17. The Brookhaven Radiation Effects Facility

    Energy Technology Data Exchange (ETDEWEB)

    Grand, P.; Snead, C.L.; Ward, T.

    1988-01-01

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H{sup -}, H{sup o}, and H{sup +} beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 {mu}s to 500 {mu}s length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 {sigma}) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs.

  18. The Brookhaven Radiation Effects Facility

    International Nuclear Information System (INIS)

    Grand, P.; Snead, C.L.; Ward, T.

    1988-01-01

    The Neutral Particle Beam (NPB) Radiation Effects Facility (REF), funded by the Strategic Defense Initiative Office (SDIO) through the Defense Nuclear Agency (DNA) and the Air Force Weapons Laboratory (AFWL), has been constructed at Brookhaven National Laboratory (BNL). Operation started in October 1986. The facility is capable of delivering pulsed H - , H/sup o/, and H + beams of 100 to 200 MeV energy up to 30 mA peak current. Pulses can be adjusted from 5 μs to 500 μs length at a repetition rate of 5 pps. The beam spot on target is adjustable from 3 to 100 cm diameter (2 σ) resulting in a maximum dose of about 10 MRads (Si) per pulse (small beam spot). Experimental use of the REF is being primarily supported by the SDI lethality (LTH-4) program. The program has addressed ionization effects in electronics, both dose rate and total dose dependence, radiation-sensitive components, and dE/dx effects in energetic materials including propellants and high explosives (HE). This paper describes the facility, its capabilities and potential, and the experiments that have been carried out to date or are being planned. 2 refs., 10 figs

  19. Effects of radiation on DNA

    International Nuclear Information System (INIS)

    Braddock, M.

    1985-07-01

    The hydroxyl radical (OH radical) is the most damaging radical produced by the effect of ionizing radiation in water. The rate of reaction of the OH radical with purified, native and isodisperse DNA has been determined as compared with calf thymus DNA. This has been achieved by direct observation of the rate of formation of the DNA-OH radical adduct, and by competition with SCN - . Results obtained from direct observation are consistent with calculations which have been performed using the encounter frequency model of Braams and Ebert. However, results obtained for OH radical with DNA derived from competition plots suggest a rate constant somewhat lower than that obtained from direct observation. The relative merits of both techniques are discussed. In order to study the effect of energy deposited directly in the DNA, dry films of purified plasmid DNA have been irradiated in a system where the indirect effects of radical interaction have been minimized. The present results indicate that with different molecular lengths of plasmid DNA, non-random breakage may occur, and that additional damage may be brought about at sites of previously existing damage. Differences in the sensitivity of plasmid DNA molecules of varying lengths to radiation induced double strand breaks have been demonstrated. (author)

  20. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    International Nuclear Information System (INIS)

    Bartlett, W.T.; Walker, B.A.

    1996-01-01

    Alpha continuous air monitors (CAMs) will be used at the Waste Isolation Pilot Plant (WIPP) to measure airborne transuranic radioactivity that might be present in air exhaust or in work-place areas. WIPP CAMs are important to health and safety because they are used to alert workers to airborne radioactivity, to actuate air-effluent filtration systems, and to detect airborne radioactivity so that the radioactivity can be confined in a limited area. In 1993, the Environmental Evaluation Group (EEG) reported that CAM operational performance was affected by salt aerosol, and subsequently, the WIPP CAM design and usage were modified. In this report, operational data and current theories on aerosol collection were reviewed to determine CAM quantitative performance limitations. Since 1993, the overall CAM performance appears to have improved, but anomalous alpha spectra are present when sampling-filter salt deposits are at normal to high levels. This report shows that sampling-filter salt deposits directly affect radon-thoron daughter alpha spectra and overall monitor efficiency. Previously it was assumed that aerosol was mechanically collected on the surface of CAM sampling filters, but this review suggests that electrostatic and other particle collection mechanisms are more important than previously thought. The mechanism of sampling-filter particle collection is critical to measurement of acute releases of radioactivity. 41 refs

  1. Impact of alpha-, gamma-, and delta-tocopherol on the radiation induced oxidation of rapeseed oil triacylglycerols

    Energy Technology Data Exchange (ETDEWEB)

    Braunrath, Robert; Isnardy, Bettina; Solar, Sonja, E-mail: sonja.solar@univie.ac.at; Elmadfa, Ibrahim

    2010-07-15

    Gamma-irradiation (doses: 2, 4, 7, and 10 kGy) was used as oxidation tool to study the antioxidant effects of alpha-, gamma-, and delta-tocopherol (enrichments 500-5000 ppm) in purified rapeseed oil triacylglycerols (RSOTG). Fatty acid composition, tocopherol degradation, primary (conjugated dienes (CD) and peroxide value (POV)) and secondary (p-anisidine value) oxidation products were chosen as test parameters. Fatty acid composition did not change. While secondary oxidation products could not be found in the irradiated samples, the POVs and CDs showed a significant, dose-dependent increase. alpha-Tocopherol did not inhibit the formation of peroxides, whereas gamma- and delta-tocopherol reduced the POVs by more than 30%. No uniform effect of the different tocopherol concentrations at the particular doses could be established. The influence of the individual tocopherols on the CD formation was not pronounced. The degradation of the tocopherols decreased with increasing concentration. None of the tocopherols showed a prooxidant effect.

  2. Effects of ionizing radiation on vitamins

    International Nuclear Information System (INIS)

    Thayer, D.W.; Fox, J.B. Jr.; Lakritz, L.

    1991-01-01

    Vitamins are known to be sensitive to the effects of ionizing radiation. Since most foods contain a large proportion of water, the most probable reaction of the ionizing radiation would be with water; and as vitamins are present in very small amounts compared with other substances in the food they will be affected indirectly by the radiation. This chapter discusses the effect of ionizing radiation on water soluble vitamins and fat soluble vitamins. (author)

  3. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  4. Medical response to effects of ionising radiation

    International Nuclear Information System (INIS)

    Crosbie, W.A.; Gittus, J.H.

    1989-01-01

    The proceedings of a conference on 'Medical Response to Effects of Ionising Radiation' in 1989 in the form of nineteen papers published as a book. Topics discussed include radiation accidents at nuclear facilities, the medical management of radiation casualties, the responsibilities, plans and resources for coping with a nuclear accident and finally the long term effects of radiation, including leukaemia epidemiology studies. All papers were selected and indexed separately. (UK)

  5. Effect of alpha linolenic acid supplementation on serum prostate specific antigen (PSA: results from the alpha omega trial.

    Directory of Open Access Journals (Sweden)

    Ingeborg A Brouwer

    Full Text Available Alpha linolenic acid (ALA is the major omega-3 fatty acid in the diet. Evidence on health effects of ALA is not conclusive, but some observational studies found an increased risk of prostate cancer with higher intake of ALA. We examined the effect of ALA supplementation on serum concentrations of prostate-specific antigen (PSA, a biomarker for prostate cancer.The Alpha Omega Trial (ClinicalTrials.gov Identifier: NCT00127452 was a double-blind, placebo-controlled trial of ALA and the fish fatty acids eicosapentanoic acid (EPA and docosahexanoic acid (DHA on the recurrence of cardiovascular disease, using a 2×2 factorial design. Blood was collected at the start and the end of the intervention period. The present analysis included 1622 patients with a history of a myocardial infarction, aged 60-80 years with an initial PSA concentration 4 ng/mL.Mean serum PSA increased by 0.42 ng/mL on placebo (n = 815 and by 0.52 ng/mL on ALA (n = 807, a difference of 0.10 (95% confidence interval: -0.02 to 0.22 ng/mL (P = 0·12. The odds ratio for PSA rising above 4 ng/mL on ALA versus placebo was 1.15 (95% CI: 0.84-1.58.An additional amount of 2 g of ALA per day increased PSA by 0.10 ng/mL, but the confidence interval ranged from -0.02 to 0.22 ng/mL and included no effect. Therefore, more studies are needed to establish whether or not ALA intake has a clinically significant effect on PSA or prostate cancer.ClinicalTrials.gov; Identifier: NCT00127452. URL: http://www.clinicaltrials.gov/ct2/show/NCT00127452.

  6. Protective Effect of Chitin Urocanate Nanofibers against Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    Ikuko Ito

    2015-12-01

    Full Text Available Urocanic acid is a major ultraviolet (UV-absorbing chromophore. Chitins are highly crystalline structures that are found predominantly in crustacean shells. Alpha-chitin consists of microfibers that contain nanofibrils embedded in a protein matrix. Acid hydrolysis is a common method used to prepare chitin nanofibrils (NFs. We typically obtain NFs by hydrolyzing chitin with acetic acid. However, in the present study, we used urocanic acid to prepare urocanic acid chitin NFs (UNFs and examined its protective effect against UVB radiation. Hos: HR-1 mice coated with UNFs were UVB irradiated (302 nm, 150 mJ/cm2, and these mice showed markedly lower UVB radiation-induced cutaneous erythema than the control. Additionally, sunburn cells were rarely detected in the epidermis of UNFs-coated mice after UVB irradiation. Although the difference was not as significant as UNFs, the number of sunburn cells in mice treated with acetic acid chitin nanofibrils (ANFs tended to be lower than in control mice. These results demonstrate that ANFs have a protective effect against UVB and suggest that the anti-inflammatory and antioxidant effects of NFs influence the protective effect of ANFs against UVB radiation. The combination of NFs with other substances that possess UV-protective effects, such as urocanic acid, may provide an enhanced protective effect against UVB radiation.

  7. Combined effects of alpha particles and depleted uranium on Zebrafish (Danio rerio) embryos

    International Nuclear Information System (INIS)

    Ng, Candy Y.P.; Pereira, Sandrine; Cheng, Shuk Han; Adam-Guillermin, Christelle; Garnier-Laplace, Jacqueline; Yu, Kwan Ngok

    2016-01-01

    The combined effects of low-dose or high-dose alpha particles and depleted uranium (DU) in Zebrafish (Danio rerio) embryos were studied. Three schemes were examined—(i) [I L U L ]: 0.44 mGy alpha-particle dose + 10 µg/l DU exposure, (ii) [I H U H ]: 4.4 mGy alpha-particle dose + 100 µg/l DU exposure and (iii) [I H U L ]: 4.4 mGy alpha-particle dose + 10 µg/l DU exposure—in which Zebrafish embryos were irradiated with alpha particles at 5 h post fertilization (hpf) and/or exposed to uranium at 5–6 hpf. The results were also compared with our previous work, which studied the effects of [I L U H ]: 0.44 mGy alpha-particle dose + 100 µg/l DU exposure. When the Zebrafish embryos developed to 24 hpf, the apoptotic signals in the entire embryos, used as the biological endpoint for this study, were quantified. Our results showed that [I L U L ] and [I H U L ] led to antagonistic effects, whereas [I H U H ] led to an additive effect. The effect found for the previously studied case of [I L U H ] was difficult to define because it was synergistic with reference to the 100 µg/l DU exposure, but it was antagonistic with reference to the 0.44 mGy alpha-particle dose. All the findings regarding the four different schemes showed that the combined effects critically depended on the dose response to each individual stressor. We also qualitatively explained these findings in terms of promotion of early death of cells predisposed to spontaneous transformation by alpha particles, interacting with the delay in cell death resulting from various concentrations of DU exposure

  8. Effect of alpha amylase on early childhood caries: a matched case-control study

    OpenAIRE

    Mojarad, Farzad; Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan; Fazlollahifar, Samira; Department of Pediatric Dentistry, School of Dentistry, Hamadan University of Medical Sciences, Hamadan; Poorolajal, Jalal; Research Center for Health Sciences, Department of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan; Hajilooi, Mehrdad; Department of Pathology, School of Dentistry, Hamadan University of Medical Sciences, Hamadan

    2013-01-01

    Objectives: There are a few studies addressing the relationship between salivary alpha-amylase and dental caries. This study was implemented in order to investigate the effect of salivary alpha-amylase level on early childhood caries (ECC).Materials and Methods: In this matched case-control study, which was carried out from November 2011 to March 2012 in Hamadan City, the west of Iran, mean levels of salivary alpha-amylase of 84 ECC-active cases were compared to that of 84 ECC-free controls u...

  9. Radiation effects in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Begay, F.; Rosen, L.; Petersen, D.F.; Mason, C.; Travis, B. [Los Alamos National Lab., NM (United States); Yazzie, A. [Navajo Nation, Window Rock, AZ (United States). Dept. of History; Isaac, M.C.P.; Seaborg, G.T. [Lawrence Berkeley National Lab., CA (United States); Leavitt, C.P. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Physics and Astronomy

    1999-04-01

    Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska.

  10. Oncogenic action of beta, proton, alpha and electron radiation on the rat skin

    International Nuclear Information System (INIS)

    Burns, F.J.

    1980-01-01

    Rat skin is being utilized as an empirical model for testing dose and time related aspects of the oncogenic action of ionizing radiation, ultraviolet light, and polycyclic aromatic hydrocarbons. Molecular lesions in the skin DNA, including, strand breaks and thymine dimers, are being measured and compared to tumor induction. The induction and repair kinetics of molcular lesions are being compared to split dose repair. Modifiers and radiosensitizers are being utilized to test specific aspects of a chromosome breakage theory of radiation oncogenesis

  11. Effects of ionizing radiation on life

    International Nuclear Information System (INIS)

    Rausch, L.

    1982-01-01

    Radiobiology in the last years was able to find detailed explanations for the effects of ionizing radiation on living organisms. But it is still impossible to make exact statements concerning the damages by radiation. Even now, science has to content itself with probability data. Moreover no typical damages of ionizing radiation can be identified. Therefore, the risks of ionizing radiation can only be determined by comparison with the spontaneous rate of cancerous or genetic defects. The article describes the interaction of high-energy radiation with the molecules of the organism and their consequences for radiation protection. (orig.)

  12. Theory of the induction of bone cancer by alpha radiation: a summary

    International Nuclear Information System (INIS)

    Marshall, J.H.; Groer, P.G.

    1976-01-01

    A theory of the induction of osteosarcoma by alpha particles is summarized. When the postulates of the theory have been written as a set of four differential equations, they have been found to provide acceptable fits to the dose-time-response surface for 226 Ra- 228 Ra in man and for 226 Ra in dogs. That is, the theory appears to fit not only the cumulative incidence as a function of radium intake for man and dog over the whole range of dose, but also the distribution of appearance times of the tumors at each dose level

  13. Alpha heating and isotopic mass effects in JET plasmas with sawteeth

    Energy Technology Data Exchange (ETDEWEB)

    Budny, R. V. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Team, JET [EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, UK

    2016-02-09

    The alpha heating experiment in the Joint European Torus (JET) 1997 DTE1 campaign is re-examined. Several effects correlated with tritium content and thermal hydrogenic isotopic mass < A> weaken the conclusion that alpha heating was clearly observed. These effects delayed the occurrence of significant sawtooth crashes allowing the electron and ion temperatures T e and T i to achieve higher values. Under otherwise equal circumstances T e and T i were typically higher for discharges with higher < A >, and significant scaling of T i, T e, and total stored energy with < A > were observed. The higher T i led to increased ion–electron heating rates with magnitudes comparable to those computed for alpha electron heating. Rates of other heating/loss processes also had comparable magnitudes. Simulations of T e assuming the observed scaling of T i are qualitatively consistent with the measured profiles, without invoking alpha heating

  14. Protective effect of exercise and alpha tocopherol on atherosclerosis promotion in hypercholesterolemic domestic rabbits

    Science.gov (United States)

    Shekh, Mudhir S.; Mahmud, Almas M. R.

    2017-09-01

    This study was designed to determine effects of exercise training (Moderate and severe) and alpha tocopherol on lipid profiles and organ weights in hypercholesterolemic domestic rabbits. Hypercholesterolemia (HC) and atherosclerotic lesions were induced by feeding the male rabbits the standard chow supplemented with 1% cholesterol (atherogenic diet) for 36 days. Experimental rabbits were divided into seven groups: normal (T1), HC control (T2), HC plus alpha tocopherol (0.5mg /animal/day) (T3), HC plus moderate exercise 40 minutes/day (0.5km/day) 5 days/week (T4), HC plus severe exercise 40 minutes/day (1km/day) 5 days/week (T5), HC plus alpha tocopherol plus moderate exercise (T6) and HC plus alpha tocopherol plus severe exercise (T7). After the treatment period of 36th day, blood samples were collected and total cholesterol (TC), Triglyceride (TG), Very low-density lipoprotein (VLDL)-cholesterol, High-density lipoproteins (HDL)-cholesterol, Low-density lipoprotein (LDL)-cholesterol, serum glucose, body and organ weights were assayed and compared with hypercholesterolemic control. Combination of moderate exercise with alpha tocopherol produced significant reduction (Pgroup showed no significant change in all lipid profiles. However, the decrement in the above parameters was comparable with hypercholesterolemic rabbits in combination of severe exercise with alpha tocopherol. The results suggest that the combination of moderate exercise with alpha tocopherol can be exploited for prevention of atherosclerosis in hypercholesterolemic rabbits.

  15. γ radiation effects on Collembola

    International Nuclear Information System (INIS)

    Loring, S.J.

    1985-01-01

    Pitfall traps were used to collect surface-active Collembola at intervals of 10-100 m from a γ radiation source on Long Island, N.Y., during the summer of 1968. Thirty-two species of Collembola were collected along the radiation transect. Community diversities were similar at all intervals except 10 m. Collembola appeared resistant to γ radiation; only chronic, very high γ radiation exposure seriously affected population levels and community diversity of surface Collembola

  16. Biologic effects of electromagnetic radiation and microwave

    International Nuclear Information System (INIS)

    Deng Hua

    2002-01-01

    Electromagnetic radiation and microwave exist mankind's environment widely. People realize they disserve authors' health when authors make use of them. Electromagnetic radiation is one of the major physic factors which injure people's health. A review of the biologic mechanism about electromagnetic radiation and microwave, their harmful effects to human body, problems in authors' research and the prospect

  17. Study of biological effect of radiation

    International Nuclear Information System (INIS)

    Li Guisheng

    1992-01-01

    The some progress on the study of biological effect for protract exposure to low dose rate radiation is reported, and it is indicated that the potential risk of this exposure for the human health and the importance of the routine monitoring of radiation dose for various nuclear installations. The potential exposure to the low dose rate radiation would attract people's extra attention

  18. Molecular and cellular effects of radiations

    International Nuclear Information System (INIS)

    Peak, M.J.; Peak, J.G.; Ito, A.; Roth, R.M.

    1985-01-01

    This program is concerned with the basic nature of the biological effects of mutagenic and carcinogenic environmental radiations, including those solar ultraviolet and visible radiations responsible for the most common form of human cancer: cancer of the skin. Concentrating on the damages to DNA caused by these radiations, the program attempts to delineate the basic mechanisms whereby such damage may occur. 14 refs

  19. Effect of decoyinine on the regulation of alpha-amylase synthesis in Bacillus subtilis.

    OpenAIRE

    Nicholson, W L; Chambliss, G H

    1987-01-01

    Decoyinine, an inhibitor of GMP synthetase, allows sporulation in Bacillus subtilis to initiate and proceed under otherwise catabolite-repressing conditions. The effect of decoyinine on alpha-amylase synthesis in B. subtilis, an event which exhibits regulatory features resembling sporulation initiation, was examined. Decoyinine did not overcome catabolite repression of alpha-amylase synthesis in a wild-type strain of B. subtilis but did cause premature and enhanced synthesis in a mutant strai...

  20. Radiation effects on biochemical systems

    International Nuclear Information System (INIS)

    Seddon, G.M.

    2000-04-01

    Xanthine oxidase catalyses the oxidative hydroxylation of hypoxanthine, xanthine and a wide range of carbonyl compounds. The enzyme exists as an oxidase and a dehydrogenase; both catalyze the oxidation of the same substrates. Steady state radiolysis and pulse radiolysis were used to generate oxidative and reductive free radicals. Their effects on the enzymatic activity of xanthine oxidase were determined. Initially inactivation studies were carried out to evaluate the extent to which radiolysis in aqueous solution affects the enzyme activity. Values of D 37 and G inactivation were calculated following irradiation in the presence of free radical scavengers and in the presence of catalase and superoxide dismutase. The kinetic constants Vmax and Km were also determined following radiolysis. The effect of ionising radiation on the iron content of xanthine oxidase was measured using atomic absorption spectrometry. Native gel electrophoresis and iso-electric focussing were performed in an attempt to demonstrate changes in the overall structure of the enzyme. The binding of xanthine oxidase to heparin was carried out by measuring, (1) the displacement of methylene blue (MB + ) from a heparin-MB + complex, (2) affinity chromatography and, (3) pulse radiolysis. The effect of irradiation on the binding process was investigated using techniques (1) and (2). Finally the radiation-induced conversion of xanthine oxidase to dehydrogenase was established. The results indicate that xanthine oxidase is inactivated greatest in the presence of air and irradiation causes Vmax to he reduced and Km to increase. The iron content of irradiated xanthine oxidase is unaffected. Electrophoresis shows the enzyme becomes fragmented and the isoelectric points of the fragments vary over a wide range of pH. Binding of xanthine oxidase to heparin as measured by displacement of MB + from a heparin-MB + complex suggests that irradiation increases the affinity of the enzyme for the polyanion, whereas

  1. The effects of radiation on man

    International Nuclear Information System (INIS)

    Saunders, P.

    1981-01-01

    Available evidence on the effects of high levels of radiation on man and the predictions which have been made on possible low level effects, by extrapolation of the high level data, are summarised. The factors which influence the biological effects of radiation are examined and acute, delayed, somatic and hereditary effects as reported in the literature, are discussed. (U.K.)

  2. Long term effects of radiation in man

    International Nuclear Information System (INIS)

    Tso Chih Ping; Idris Besar

    1984-01-01

    An overview of the long term effects of radiation in man is presented, categorizing into somatic effects, genetic effects and teratogenic effects, and including an indication of the problems that arise in their determination. (author)

  3. Note: Real time optical sensing of alpha-radiation emitting radioactive aerosols based on solid state nuclear track detector

    International Nuclear Information System (INIS)

    Kulkarni, A.; Bak, M. S.; Ha, S.; Joshirao, P.; Manchanda, V.; Kim, T.

    2015-01-01

    A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO 3 ) 4 ⋅ 5H 2 O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories

  4. Note: Real time optical sensing of alpha-radiation emitting radioactive aerosols based on solid state nuclear track detector

    Science.gov (United States)

    Kulkarni, A.; Ha, S.; Joshirao, P.; Manchanda, V.; Bak, M. S.; Kim, T.

    2015-06-01

    A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO3)4 ṡ 5H2O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories.

  5. Note: Real time optical sensing of alpha-radiation emitting radioactive aerosols based on solid state nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, A.; Bak, M. S., E-mail: tkim@skku.edu, E-mail: moonsoo@skku.edu [School of Mechanical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Ha, S. [SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Joshirao, P.; Manchanda, V. [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, T., E-mail: tkim@skku.edu, E-mail: moonsoo@skku.edu [School of Mechanical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-06-15

    A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO{sub 3}){sub 4} ⋅ 5H{sub 2}O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories.

  6. Resolution of G(s)alpha and G(q)alpha/G(11)alpha proteins in membrane domains by two-dimensional electrophoresis: the effect of long-term agonist stimulation.

    Science.gov (United States)

    Matousek, P; Novotný, J; Svoboda, P

    2004-01-01

    Low-density membrane-domain fractions were prepared from S49 lymphoma cells and clone e2m11 of HEK293 cells expressing a large number of thyrotropin-releasing hormone receptor (TRH-R) and G(11)alpha by flotation on sucrose density gradients. The intact cell structure was broken by detergent-extraction, alkaline-treatment or drastic homogenization. Three types of low-density membranes were resolved by two-dimensional electrophoresis and analyzed for G(s)alpha (S49) or G(q)alpha/G11) (e2m11) content. Four individual immunoblot signals of Gsalpha protein were identified in S49 lymphoma cells indicating complete resolution of the long G(s)alpha L+/-ser and short G(s)alpha S+/-ser variants of G(s)alpha. All these were diminished by prolonged agonist (isoprenaline) stimulation. In e2m11-HEK cells, five different immunoblot signals were detected indicating post-translational modification of G proteins of G(q)alpha/G(11)alpha family. The two major spots corresponding to exogenously (over)expressed G(11)alpha and endogenous G(q)alpha were reduced; the minor spots diminished by hormonal stimulation. Parallel analysis by silver staining of the total protein content indicated that no major changes in protein composition occurred under these conditions. Our data thus indicate that agonist-stimulation of target cells results in down-regulation of all different members of G(s) and G(q)/G(11) families. This agonist-specific effect may be demonstrated in crude membrane as well as domain/raft preparations and it is not accompanied by changes in overall protein composition.

  7. Radiation effects on materials in high-radiation environments

    International Nuclear Information System (INIS)

    Weber, W.J.; Mansur, L.K.; Clinard, F.W. Jr.; Parkin, D.M.

    1991-01-01

    A workshop on Radiation Effects on Materials in High-Radiation Environments was held in Salt Lake City, Utah (USA) from August 13 to 15, 1990 under the auspices of the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy. The workshop focused on ceramics, alloys, and intermetallics and covered research needs and capabilities, recent experimental data, theory, and computer simulations. It was concluded that there is clearly a continuing scientific and technological need for fundamental knowledge on the underlying causes of radiation-induced property changes in materials. Furthermore, the success of many current and emerging nuclear-related technologies critically depend on renewed support for basic radiation-effects research, irradiation facilities, and training of scientists. The highlights of the workshop are reviewed and specific recommendations are made regarding research needs. (orig.)

  8. Graphene Field Effect Transistor for Radiation Detection

    Science.gov (United States)

    Li, Mary J. (Inventor); Chen, Zhihong (Inventor)

    2016-01-01

    The present invention relates to a graphene field effect transistor-based radiation sensor for use in a variety of radiation detection applications, including manned spaceflight missions. The sensing mechanism of the radiation sensor is based on the high sensitivity of graphene in the local change of electric field that can result from the interaction of ionizing radiation with a gated undoped silicon absorber serving as the supporting substrate in the graphene field effect transistor. The radiation sensor has low power and high sensitivity, a flexible structure, and a wide temperature range, and can be used in a variety of applications, particularly in space missions for human exploration.

  9. Influence of some exo nucleases in response to the induced genetic damage in Escherichia coli by alpha radiation

    International Nuclear Information System (INIS)

    Aguilar M, M.

    2005-01-01

    Within the strategies with those that E. coli counts to overcome to the genetic damage there is the SOS response, a group of genes that participate in repair and/or tolerance that it confers to the bacteria major opportunities of surviving. These genes are repressed and its only are expressed when it happens genetic damage. So that this system is activated it is necessary that DNA of a band exists and in this sense the double ruptures (RDB) its are not able to induce this response unless there is a previous processing. In stumps with defects in certain genes that have to do with repair of RDB (as recO, recJ and xonA) the activity of SOS is smaller than in a wild stump what suggests that these participate in the previous processes to the activation of the response. The ionizing radiation produce among other many lesions, RDB in greater or smaller proportion, depending on the ionization capacity. A parameter to evaluate this capacity is the lineal energy transfer (LET), defined as the average energy given by unit of distance travelled. In general the LET of the corpuscular radiations is a lot but high that of the electromagnetic one, for what produces bigger quantity of ionizations inside a restricted zone and it increases by this way the probability that RDB has been generated. This work has for object to infer the participation of xonA and recJ in this response and to evaluate the damage produced by ionizing radiation of different LET (alpha particles of different energies) in a stump with all the functional repair mechanisms. Its were considered two parameters: the survival and the activity of SOS evaluated by means of the chromo test. The results indicate that the activity of these exo nucleases is necessary for the repair of RDB as well as for the processing of lesions foresaw to the activation of SOS. As for the treatment with alphas of different energies is observed that so much the survival like the activity of SOS vary as the LET of the radiation changes

  10. Biodistribution and radiation dosimetry of the {alpha}{sub 7} nicotinic acetylcholine receptor ligand [{sup 11}C]CHIBA-1001 in humans

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, Muneyuki [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022 (Japan); Wu, Jin; Toyohara, Jun [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022 (Japan); Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Oda, Keiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022 (Japan); Ishikawa, Masatomo [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022 (Japan); Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022 (Japan); Hashimoto, Kenji [Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Ishiwata, Kiichi, E-mail: ishiwata@pet.tmig.or.j [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1 Naka-cho, Itabashi-ku, Tokyo 173-0022 (Japan)

    2011-04-15

    Introduction: 4-[{sup 11}C]Methylphenyl 2,4-diazabicyclo[3.2.2]nonane-2-carboxylate ([{sup 11}C]CHIBA-1001) is a newly developed positron emission tomography (PET) ligand for mapping {alpha}{sub 7} nicotinic acetylcholine receptors. We investigated whole-body biodistribution and radiation dosimetry of [{sup 11}C]CHIBA-1001 in humans and compared the results with those obtained in mice. Methods: Dynamic whole-body PET was carried out for three human subjects after administering a bolus injection of [{sup 11}C]CHIBA-1001. Emission scans were collected in two-dimensional mode over five bed positions. Regions of interest were placed over 12 organs. Radiation dosimetry was estimated from the residence times of these source organs using the OLINDA program. Biodistribution data from mice were also used for the prediction of radiation dosimetry in humans, and results with and those without accommodation of different proportions of organ-to-total-body mass were compared with the results from the human PET study. Results: In humans, the highest accumulation was observed in the liver, whereas in mice, the highest accumulation was observed in the urinary bladder. The estimated effective dose from the human PET study was 6.9 {mu}Sv/MBq, and that from mice was much underestimated. Conclusion: Effective dose estimates for [{sup 11}C]CHIBA-1001 were compatible with those associated with other common nuclear medicine tests. Absorption doses among several organs were considerably different between the human and mouse studies. Human dosimetry studies for the investigation of radiation safety are desirable as one of the first clinical trials of new PET probes before their application in subsequent clinical investigations.

  11. Radiation-induced polymerization and radiation effect on polymers

    International Nuclear Information System (INIS)

    Seguchi, Tadao

    1977-12-01

    The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

  12. Untargeted effects of ionizing radiation: Implications for radiation pathology

    International Nuclear Information System (INIS)

    Wright, Eric G; Coates, Philip J

    2006-01-01

    The dogma that genetic alterations are restricted to directly irradiated cells has been challenged by observations in which effects of ionizing radiation, characteristically associated with the consequences of energy deposition in the cell nucleus, arise in non-irradiated cells. These, so called, untargeted effects are demonstrated in cells that have received damaging signals produced by irradiated cells (radiation-induced bystander effects) or that are the descendants of irradiated cells (radiation-induced genomic instability). Radiation-induced genomic instability is characterized by a number of delayed adverse responses including chromosomal abnormalities, gene mutations and cell death. Similar effects, as well as responses that may be regarded as protective, have been attributed to bystander mechanisms. Whilst the majority of studies to date have used in vitro systems, some adverse non-targeted effects have been demonstrated in vivo. However, at least for haemopoietic tissues, radiation-induced genomic instability in vivo may not necessarily be a reflection of genomically unstable cells. Rather the damage may reflect responses to ongoing production of damaging signals; i.e. bystander responses, but not in the sense used to describe the rapidly induced effects resulting from direct interaction of irradiated and non-irradiated cells. The findings are consistent with a delayed and long-lived tissue reaction to radiation injury characteristic of an inflammatory response with the potential for persisting bystander-mediated damage. An important implication of the findings is that contrary to conventional radiobiological dogma and interpretation of epidemiologically-based risk estimates, ionizing radiation may contribute to malignancy and particularly childhood leukaemia by promoting initiated cells rather than being the initiating agent. Untargeted mechanisms may also contribute to other pathological consequences

  13. A-bomb radiation effects digest

    International Nuclear Information System (INIS)

    Shigematsu, Itsuzo; Akiyama, Mitoshi; Sasaki, Hideo; Ito, Chikako; Kamada, Nanao.

    1993-01-01

    This publication is the digest of the book 'Genbaku Hoshasen no Jintai Eikyo (Effects of A-bomb Radiation on the Human Body)' (365p.), published in Japanese by Hiroshima International Council for Medical Care of the Radiation-Exposed. Following a brief description on the damage of the atomic bomb, the subjects of malignant tumors, endocrine and metabolic deseases, ocular lesions, dermatologic effects, prenatal exposure, chromosoal aberrations, mutations, sensitivity to radiation, immune function, genetic effects and other effects of radiation are summarized. (J.P.N.)

  14. Radiation dose to the lungs due to inhalation of alpha emitters

    International Nuclear Information System (INIS)

    Haque, A.K.M.M.; Al-Affan, I.A.M.

    1987-01-01

    The radiation dose to the lungs due to inhalation of radon daughters has been computed with improved data on lung models, aerosol parameters, deposition and clearance mechanisms. The dose corresponds to mean radon concentration of 23 Bq/m 3 indoors (recent NRPB Survey) for different living conditions. The dose rate to basal cells in gen. 5 is 12 mGy/WLM. (author)

  15. Long-term effects of ionizing radiation

    International Nuclear Information System (INIS)

    Kaul, Alexander; Burkart, Werner; Grosche, Bernd; Jung, Thomas; Martignoni, Klaus; Stephan, Guenther

    1997-01-01

    This paper approaches the long-term effects of ionizing radiation considering the common thought that killing of cells is the basis for deterministic effects and that the subtle changes in genetic information are important in the development of radiation-induced cancer, or genetic effects if these changes are induced in germ cells

  16. Radiation hazards and their effects

    International Nuclear Information System (INIS)

    Lunu, Shyam; Kumar, Hemant; Joshi, Pankaj Kumar; Songara, Venkteshwer

    2012-01-01

    Radiation can be classified into ionizing radiation and non-ionizing radiation, based on whether it is capable of ionizing atoms and breaking chemical bonds. Ultraviolet and higher frequency such as X-rays, gamma rays are ionizing. These pose their own special hazards. Non ionizing radiation is associated with two major potential hazards. i.e. electrical and biological. Additionally includes electric current caused by radiation can generate sparks and create a fire or explosive hazards. Strong radiation can induce current capable of delivering an electric shock. Extremely high power electromagnetic radiation can cause electric currents strong enough to create sparks when an induced voltage exceeds the breakdown voltage of surrounding mediums. A 2009 study at the University of Basal in Switzerland found that intermitted exposure of human cells to a 50 Hz electromagnetic field at a flux density of 10 Gy induced a slight but significant increase of DNA fragmentation in the comet assay. Mobile phones radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world. Mobile phones use electromagnetic radiation in the microwaves range and some believes this may be harmful to human health. (author)

  17. Effects of total dose of ionizing radiation on integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Marcilei A.G.; Cirne, K.H.; Gimenez, S.; Santos, R.B.B. [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Added, N.; Barbosa, M.D.L.; Medina, N.H.; Tabacniks, M.H. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Lima, J.A. de; Seixas Junior, L.E.; Melo, W. [Centro de Tecnologia da Informacao Paulo Archer, Sao Paulo, SP (Brazil)

    2011-07-01

    Full text: The study of ionizing radiation effects on materials used in electronic devices is of great relevance for the progress of global technological development and, particularly, it is a necessity in some strategic areas in Brazil. Electronic circuits are strongly influenced by radiation and the need for IC's featuring radiation hardness is largely growing to meet the stringent environment in space electronics. On the other hand, aerospace agencies are encouraging both scientific community and semiconductors industry to develop hardened-by-design components using standard manufacturing processes to achieve maximum performance, while significantly reducing costs. To understand the physical phenomena responsible for changes in devices exposed to ionizing radiation several kinds of radiation should then be considered, among them alpha particles, protons, gamma and X-rays. Radiation effects on the integrated circuits are usually divided into two categories: total ionizing dose (TID), a cumulative dose that shifts the threshold voltage and increases transistor's off-state current; single events effects (SEE), a transient effect which can deposit charge directly into the device and disturb the properties of electronic circuits. TID is one of the most common effects and may generate degradation in some parameters of the CMOS electronic devices, such as the threshold voltage oscillation, increase of the sub-threshold slope and increase of the off-state current. The effects of ionizing radiation are the creation of electron-hole pairs in the oxide layer changing operation mode parameters of the electronic device. Indirectly, there will be also changes in the device due to the formation of secondary electrons from the interaction of electromagnetic radiation with the material, since the charge carriers can be trapped both in the oxide layer and in the interface with the oxide. In this work we have investigated the behavior of MOSFET devices fabricated with

  18. Effect of radiation-induced amorphization on smectite dissolution.

    Science.gov (United States)

    Fourdrin, C; Allard, T; Monnet, I; Menguy, N; Benedetti, M; Calas, G

    2010-04-01

    Effects of radiation-induced amorphization of smectite were investigated using artificial irradiation. Beams of 925 MeV Xenon ions with radiation dose reaching 73 MGy were used to simulate the effects generated by alpha recoil nuclei or fission products in the context of high level nuclear waste repository. Amorphization was controlled by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. An important coalescence of the smectite sheets was observed which lead to a loss of interparticle porosity. The amorphization is revealed by a loss of long-range structure and accompanied by dehydroxylation. The dissolution rate far-from-equilibrium shows that the amount of silica in solution is two times larger in the amorphous sample than in the reference clay, a value which may be enhanced by orders of magnitude when considering the relative surface area of the samples. Irradiation-induced amorphization thus facilitates dissolution of the clay-derived material. This has to be taken into account for the safety assessment of high level nuclear waste repository, particularly in a scenario of leakage of the waste package which would deliver alpha emitters able to amorphize smectite after a limited period of time.

  19. Fracture toughness in nuclear waste glasses and ceramics: environmental and radiation effects

    International Nuclear Information System (INIS)

    Weber, W.J.; Matzke, H.J.

    1986-03-01

    The effects of atmospheric moisture and radiation damage on fracture properties of nuclear waste glasses and ceramics was investigated by indentation techniques. In nuclear waste glasses, atmospheric moisture has no measurable effect on hardness but decreases the fracture toughness; radiation damage, on the other hand, decreased the hardness and increased the fracture toughness. In nuclear ceramics, self-radiation damage from alpha decay decreased the hardness and elastic modules; the fracture toughness increased with dose to a broad maximum and then decreased slightly with further increases in dose

  20. Tumorigenic action of beta, proton, alpha and electron radiation on the rat skin

    International Nuclear Information System (INIS)

    Burns, F.J.

    1980-01-01

    Rat skin is utilized as a model system for studying dose and time related aspects of the oncogenic action of ionizing radiation, ultraviolet light and polycyclic aromatic hydrocarbons. Molecular lesions in the DNA of the epidermis, including strand breaks and thymine dimers, are measured and compared to the temporal and dose related aspects of tumor induction. The induction and repair kinetics of molecular lesions are compared to split dose recovery as modified by sensitizers and type of radition of oncogenic damage

  1. Some characteristics and effects of natural radiation

    International Nuclear Information System (INIS)

    Mc Laughlin, J.P.

    2015-01-01

    Since life first appeared on the Earth, it has, in all its subsequent evolved forms including human, been exposed to natural radiation in the environment both from terrestrial and extra-terrestrial sources. Being an environmental mutagen, ionising natural radiation may have played a role of some significance in the evolution of early life forms on Earth. It has been estimated by United Nations Scientific Committee on the Effects of Atomic Radiation that at the present time, exposure to natural radiation globally results in an annual average individual effective dose of about 2.4 mSv. This represents about 80 % of the total dose from all sources. The three most important components of natural radiation exposure are cosmic radiation, terrestrial radioactivity and indoor radon. Each of these components exhibits both geographical and temporal variabilities with indoor radon exposure being the most variable and also the largest contributor to dose for most people. In this account, an overview is given of the characteristics of the main components of the natural radiation environment and some of their effects on humans. In the case of cosmic radiation, these range from radiation doses to aircrew and astronauts to the controversial topic of its possible effect on climate change. In the case of terrestrial natural radiation, accounts are given of a number of human exposure scenarios. (author)

  2. Alpha and beta adrenergic effects on metabolism in contracting, perfused muscle

    DEFF Research Database (Denmark)

    Richter, Erik; Ruderman, N B; Galbo, H

    1982-01-01

    The role of alpha- and beta-adrenergic receptor stimulation for the effect of epinephrine on muscle glycogenolysis, glucose- and oxygen uptake and muscle performance was studied in the perfused rat hindquarter at rest and during electrical stimulation (60 contractions/min). Adrenergic stimulation...... was obtained by epinephrine in a physiological concentration (2.4 X 10(-8) M) and alpha- and beta-adrenergic blockade by 10(-5) M phentolamine and propranolol, respectively. Epinephrine enhanced net glycogenolysis during contractions most markedly in slow-twitch red fibers. In these fibers the effect...... was mediated by alpha- as well as by beta-adrenergic stimulation, the latter involving production of cAMP, phosphorylase activation and synthase inactivation. In contrast, in fast-twitch fibers only beta-adrenergic mechanisms were involved in the glycogenolytic effect of epinephrine. Moreover, inactivation...

  3. Radiation effects in ice: New results

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Fama, M.; Loeffler, M.J.; Raut, U.; Shi, J.

    2008-01-01

    Studies of radiation effects in ice are motivated by intrinsic interest and by applications in astronomy. Here we report on new and recent results on radiation effects induced by energetic ions in ice: amorphization of crystalline ice, compaction of microporous amorphous ice, electrostatic charging and dielectric breakdown and correlated structural/chemical changes in the irradiation of water-ammonia ices

  4. Radiation effects of ion beams on polymers

    International Nuclear Information System (INIS)

    Tagawa, Seiichi

    1993-01-01

    Recent progress in the radiation effects of ion beams on polymers are reviewed briefly. Our recent work on the radiation effects of ion beams on polystyrene thin films on silicon wafers and time resolved emission studies on polymers are described. (orig.)

  5. Health effects models for nuclear power plant accident consequence analysis. Modification of models resulting from addition of effects of exposure to alpha-emitting radionuclides: Revision 1, Part 2, Scientific bases for health effects models, Addendum 2

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamson, S. [Wisconsin Univ., Madison, WI (United States); Bender, M.A. [Brookhaven National Lab., Upton, NY (United States); Boecker, B.B.; Scott, B.R. [Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States). Inhalation Toxicology Research Inst.; Gilbert, E.S. [Pacific Northwest Lab., Richland, WA (United States)

    1993-05-01

    The Nuclear Regulatory Commission (NRC) has sponsored several studies to identify and quantify, through the use of models, the potential health effects of accidental releases of radionuclides from nuclear power plants. The Reactor Safety Study provided the basis for most of the earlier estimates related to these health effects. Subsequent efforts by NRC-supported groups resulted in improved health effects models that were published in the report entitled {open_quotes}Health Effects Models for Nuclear Power Plant Consequence Analysis{close_quotes}, NUREG/CR-4214, 1985 and revised further in the 1989 report NUREG/CR-4214, Rev. 1, Part 2. The health effects models presented in the 1989 NUREG/CR-4214 report were developed for exposure to low-linear energy transfer (LET) (beta and gamma) radiation based on the best scientific information available at that time. Since the 1989 report was published, two addenda to that report have been prepared to (1) incorporate other scientific information related to low-LET health effects models and (2) extend the models to consider the possible health consequences of the addition of alpha-emitting radionuclides to the exposure source term. The first addendum report, entitled {open_quotes}Health Effects Models for Nuclear Power Plant Accident Consequence Analysis, Modifications of Models Resulting from Recent Reports on Health Effects of Ionizing Radiation, Low LET Radiation, Part 2: Scientific Bases for Health Effects Models,{close_quotes} was published in 1991 as NUREG/CR-4214, Rev. 1, Part 2, Addendum 1. This second addendum addresses the possibility that some fraction of the accident source term from an operating nuclear power plant comprises alpha-emitting radionuclides. Consideration of chronic high-LET exposure from alpha radiation as well as acute and chronic exposure to low-LET beta and gamma radiations is a reasonable extension of the health effects model.

  6. Regulation of bovine kidney alpha-ketoglutarate dehydrogenase complex by calcium ion and adenine nucleotides. Effects on S0.5 for alpha-ketoglutarate.

    Science.gov (United States)

    Lawlis, V B; Roche, T E

    1981-04-28

    Regulation of bovine kidney alpha-ketoglutarate dehydrogenase complex by energy-linked metabolites was investigated. Ca2+, ADP, or inorganic phosphate markedly enhanced the activity of the complex, and ATP or, to a lesser extent, GTP decreased the activity of the complex. Initial velocity studies with alpha-ketoglutarate as the varied substrate demonstrated that these modulators induced large changes in S0.5 for alpha-ketoglutarate (based on analysis in Hill plots) with no change in the maximum velocity (as determined by double-reciprocal plots). For all conditions studied, the Hill coefficients were significantly less than 1.0 with slopes that were linear over wide ranges of alpha-ketoglutarate concentrations, indicating negative cooperativity that probably resulted from multiple site-site interactions. Ca2+ (maintained at 10 muM by a Ca2+ buffer) decreased the S0.5 for alpha-ketoglutarate 63-fold (from 25 to 0.40 mM); even in the presence of a positive effector, ADP or phosphate, Ca2+ decreased the S0.5 for alpha-ketoglutarate 7.8- or 28-fold, respectively. Consistent with a mechanism of action dependent of Ca2+, ADP (1.60 mM) or phosphate (20 mM) reduced the S0.5 for alpha-ketoglutarate in the presence of Ca2+ (i.e., 4.5- or 1.67-fold, respectively); however, these effectors elicited larger decreases in S0.5 in the absence of Ca2+ (i.e., 37- or 3.7-fold, respectively). ATP (1.6 mM) increased the S0.5 for alpha-ketoglutarate, and Ca2+ appreciably reduced the effect, lowering the S0.5 98-fold from 66 to 0.67 mM. Thus the activity of the kidney alpha-ketoglutarate dehydrogenase complex is poised to increase as the energy potential in mitochondria declines, and Ca2+ has a pronounced modulatory effect. Comparative studies on bovine heart alpha-ketoglutarate dehydrogenase complex and the effects of varying the ADP/ATP ratio in the presence or absence of Ca2+ or phosphate are also described.

  7. [Radiation-induced bystander effect: the important part of ionizing radiation response. Potential clinical implications].

    Science.gov (United States)

    Wideł, Maria; Przybyszewski, Waldemar; Rzeszowska-Wolny, Joanna

    2009-08-18

    It has long been a central radiobiological dogma that the damaging effects of ionizing radiation, such as cell death, cytogenetic changes, apoptosis, mutagenesis, and carcinogenesis, are the results of the direct ionization of cell structures, particularly DNA, or indirect damage via water radiolysis products. However, several years ago attention turned to a third mechanism of radiation, termed the "bystander effect" or "radiation-induced bystander effect" (RIBE). This is induced by agents and signals emitted by directly irradiated cells and manifests as a lowering of survival, cytogenetic damage, apoptosis enhancement, and biochemical changes in neighboring non-irradiated cells. The bystander effect is mainly observed in in vitro experiments using very low doses of alpha particles (range; mGy, cGy), but also after conventional irradiation (X-rays, gamma rays) at low as well as conventional doses. The mechanisms responsible for the bystander effect are complex and still poorly understood. It is believed that molecular signals released from irradiated cells induce different signaling ways in non-irradiated neighboring cells, leading to the observed events. The molecular signals may be transmitted through gap junction intercellular communication and through a medium transfer mechanism. The nature of these transmitted factors are diverse, and still not definitely established. It seems that RIBE may have important clinical implications for health risk associated with radiation exposure. Potentially, this effect may have important implications in the creation of whole-body or localized side effects in tissues beyond the irradiation field and also in low-dose radiological and radioisotope diagnostics. Factors emitted by irradiated cells may result in the risk of genetic instability, mutations, and second primary cancer induction. They might also have their own part in inducing and extending post-radiation side effects in normal tissue. The bystander effect may be a

  8. Radiobiologic effects at low radiation levels

    International Nuclear Information System (INIS)

    Casarett, G.W.

    1975-01-01

    Data are reviewed on the effects of low radiation doses on mammals. Data from the 1972 report on the Biological Effects of Ionizing Radiation issued by the Advisory Committee of the National Academy of Sciences and National Research Council are discussed. It was concluded that there are certain radiosensitive systems in which low doses of radiation may cause degenerative effects, including gametogenic epithelium, lens of the eye, and developing embryos. Despite extensive investigation of genetic effects, including chromosomal effects, neither the amount of change that will be caused by very low levels of irradiation nor the degree of associated detriment is known

  9. Real-time, automated characterization of surfaces for alpha and beta radiation

    International Nuclear Information System (INIS)

    Egidi, P.V.

    1997-01-01

    A new data collection system, called ABACUS trademark, has been developed that automates and expedites the collection, conversion, and reporting of radiological survey data of surfaces. Field testing of the system by Oak Ridge National Laboratory/Environmental Technology Section is currently underway. Preliminary results are presented. The system detects, discriminates, and separately displays the results for alpha and beta contamination scans on floors and walls with a single pass. Fixed-position static counting is also possible for quantitative measuring. The system is currently configured with five 100 cm 2 dual-phosphor plastic scintillation detectors mounted in a lightweight aluminum fixture that holds the detectors in a fixed array. ABACUS trademark can be configured with other detectors if desired. Ratemeter/scalars traditionally coupled to individual detectors have been replaced by a single unit that houses the power supply and discriminator circuit boards to support up to five detectors. The system is designed to be used by a single operator. Each detector's position and data are transmitted once per second and recorded on a nearby laptop computer. The data are converted to appropriate units, color-coded, and mapped to display graphically the findings for each detector in real-time. Reports can be generated immediately following the survey. Survey data can be exported in a variety of formats. Benefits of ABACUS trademark are: (1) immediate feedback to decision makers using the observational approach to characterization or remediation, (2) thorough documentation of survey results, (3) increased statistical confidence in scans by recording counts every second, (4) reduced paperwork and elimination of transcription errors, and (5) time and cost savings for collection, conversion, mapping, evaluating, and reporting data over traditional methods

  10. Physics of intense, high energy radiation effects.

    Energy Technology Data Exchange (ETDEWEB)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-02-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic

  11. Physics of intense, high energy radiation effects

    International Nuclear Information System (INIS)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-01-01

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic calculations, the

  12. Properties and Gamma Radiation Stability of Immobilized Alpha Amylase on Synthetic and Natural Polymer Blends

    International Nuclear Information System (INIS)

    Ismaill, S.A.; Mobasher, E.F.; Shousha, M.A.

    2009-01-01

    αAmylase was immobilized onto two different copolymers. One of them was chitosan/alginate copolymer. The other copolymer was N- isopropyl acrylamide and alginate. αAmylase was immobilized by entrapment method. The optimum temperature and thermal inactivation of the free enzyme and the immobilized one were investigated. The activity of the immobilized enzyme was stable at higher temperature. Immobilized enzyme was stable under different ph. The immobilized enzymes showed a slight decrease in the relative activity after being used 12 times. Storage of the free and immobilized enzymes for 2 months showed that the free αamylase lost most of its catalytic activity after storage at this period. The storage of the immobilized enzyme in dry state was much better than that in the wet state. Storage at room temperature showed much less stability of the immobilized enzyme than in 4 degree C. Exposure the free and immobilized enzymes to gamma- radiation at doses (0-50 kGy) showed complete loss in activity of free enzyme at 5 kGy, while the immobilized enzyme showed high resistance to gamma- radiation. The kinetic studies of free and immobilized enzymes showed that the immobilization process increased Km and decreased V m ax values of the enzyme

  13. Properties and Gamma Radiation Stability of Immobilized Alpha Amylase on Synthetic and Natural Polymer Blends

    International Nuclear Information System (INIS)

    Ismaill, S.A.; Mobasher, E.F.; Shousha, M.A.

    2008-01-01

    αAmylase was immobilized onto two different copolymers. One of them was chitosan/alginate copolymer. The other copolymer was N- isopropyl acrylamide and alginate. αAmylase was immobilized by entrapment method. The optimum temperature and thermal inactivation of the free enzyme and the immobilized one were investigated. The activity of the immobilized enzyme was stable at higher temperature. Immobilized enzyme was stable under different ph. The immobilized enzymes showed a slight decrease in the relative activity after being used 12 times. Storage of the free and immobilized enzymes for 2 months showed that the free αamylase lost most of its catalytic activity after storage at this period. The storage of the immobilized enzyme in dry state was much better than that in the wet state. Storage at room temperature showed much less stability of the immobilized enzyme than in 4 degree C. Exposure the free and immobilized enzymes to gamma- radiation at doses (0-50 kGy) showed complete loss in activity of free enzyme at 5 kGy, while the immobilized enzyme showed high resistance to gamma- radiation. The kinetic studies of free and immobilized enzymes showed that the immobilization process increased Km and decreased V m ax values of the enzyme

  14. Radiation Effects on Polymers - XI

    DEFF Research Database (Denmark)

    Ghanem, N. A.; El-Awady, N. I.; Singer, Klaus Albert Julius

    1979-01-01

    With the aim of improving properties of cellulose acetate membranes for reverse osmosis desalination, grafting was performed using high energy electrons. In this paper, the grafting parameters (radiation dose and method, monomer concentration, solvents, chain transfer agent and redox system...

  15. Radiation effects in polycarbonate capacitors

    Directory of Open Access Journals (Sweden)

    Vujisić Miloš

    2009-01-01

    Full Text Available The aim of this paper is to examine the influence of neutron and gamma irradiation on the dissipation factor and capacitance of capacitors with polycarbonate dielectrics. The operation of capacitors subject to extreme conditions, such as the presence of ionizing radiation fields, is of special concern in military industry and space technology. Results obtained show that the exposure to a mixed neutron and gamma radiation field causes a decrease of capacitance, while the loss tangent remains unchanged.

  16. Low-dose radiation pretreatment improves survival of human ceiling culture-derived proliferative adipocytes (ccdPAs) under hypoxia via HIF-1 alpha and MMP-2 induction

    International Nuclear Information System (INIS)

    Adachi, Naoki; Kubota, Yoshitaka; Kosaka, Kentarou; Akita, Shinsuke; Sasahara, Yoshitarou; Kira, Tomoe; Kuroda, Masayuki; Mitsukawa, Nobuyuki; Bujo, Hideaki; Satoh, Kaneshige

    2015-01-01

    Poor survival is a major problem of adipocyte transplantation. We previously reported that VEGF and MMPs secreted from transplanted adipocytes are essential for angiogenesis and adipogenesis. Pretreatment with low-dose (5 Gy) radiation (LDR) increased VEGF, MMP-2, and HIF-1 alpha mRNA expression in human ceiling culture-derived proliferative adipocytes (hccdPAs). Gene expression after LDR differed between adipose-derived stem cells (hASCs) and hccdPAs. Pretreatment with LDR improved the survival of hccdPAs under hypoxia, which is inevitable in the early stages after transplantation. Upregulation of VEGF and MMP-2 after LDR in hccdPAs is mediated by HIF-1 alpha expression. Our results suggest that pretreatment with LDR may improve adipocyte graft survival in a clinical setting through upregulation of VEGF and MMP-2 via HIF-1 alpha. - Highlights: • Ceiling culture-derived proliferative adipocytes (ccdPAs) react to radiation. • Low-dose radiation (LDR) pretreatment improves survival of ccdPAs under hypoxia. • Gene expression after LDR differs between ccdPAs and adipose-derived stem cells. • LDR-induced increase in MMP-2 and VEGF is dependent on HIF-1 alpha induction. • LDR pretreatment may improve the adipocyte graft survival rate in clinical settings

  17. Low-dose radiation pretreatment improves survival of human ceiling culture-derived proliferative adipocytes (ccdPAs) under hypoxia via HIF-1 alpha and MMP-2 induction

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Naoki [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Kubota, Yoshitaka, E-mail: kubota-cbu@umin.ac.jp [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Kosaka, Kentarou; Akita, Shinsuke; Sasahara, Yoshitarou; Kira, Tomoe [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Kuroda, Masayuki [Center for Advanced Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Mitsukawa, Nobuyuki [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan); Bujo, Hideaki [Department of Clinical-Laboratory and Experimental-Research Medicine, Toho University, Sakura Medical Center, 564-1 Shimoshizu, Sakura-shi, Chiba, #285-8741 (Japan); Satoh, Kaneshige [Department of Plastic Surgery, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba, #260-8677 (Japan)

    2015-08-07

    Poor survival is a major problem of adipocyte transplantation. We previously reported that VEGF and MMPs secreted from transplanted adipocytes are essential for angiogenesis and adipogenesis. Pretreatment with low-dose (5 Gy) radiation (LDR) increased VEGF, MMP-2, and HIF-1 alpha mRNA expression in human ceiling culture-derived proliferative adipocytes (hccdPAs). Gene expression after LDR differed between adipose-derived stem cells (hASCs) and hccdPAs. Pretreatment with LDR improved the survival of hccdPAs under hypoxia, which is inevitable in the early stages after transplantation. Upregulation of VEGF and MMP-2 after LDR in hccdPAs is mediated by HIF-1 alpha expression. Our results suggest that pretreatment with LDR may improve adipocyte graft survival in a clinical setting through upregulation of VEGF and MMP-2 via HIF-1 alpha. - Highlights: • Ceiling culture-derived proliferative adipocytes (ccdPAs) react to radiation. • Low-dose radiation (LDR) pretreatment improves survival of ccdPAs under hypoxia. • Gene expression after LDR differs between ccdPAs and adipose-derived stem cells. • LDR-induced increase in MMP-2 and VEGF is dependent on HIF-1 alpha induction. • LDR pretreatment may improve the adipocyte graft survival rate in clinical settings.

  18. Biological effects of high LET radiations

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Masami [Nagasaki Univ. (Japan). Faculty of Pharmaceutical Sciences

    1997-03-01

    Biological effect of radiation is different by a kind of it greatly. Heavy ions were generally more effective in cell inactivation, chromosome aberration induction, mutation induction and neoplastic cell transformation induction than {gamma}-rays in SHE cells. (author)

  19. Genetic effects of ionizing radiation

    International Nuclear Information System (INIS)

    Myers, D.K.; Childs, J.D.

    1980-01-01

    The genetic material in living organisms is susceptible to damage from a wide variety of causes including radiation exposure. Most of this damage is repaired by the organism; the residual damage and damage which is not correctly repaired can lead to genetic changes such as mutations. In lower organisms, most offspring carry an unaltered copy of the genetic information that was present in the parental organism, most of the genetic changes which do occur are not caused by natural background radiation, and the increase in frequency of genetic changes after irradiation at low-dose rates is directly proportional to total radiation dose. The same principles appear to be valid in mammals and other higher organisms. About 105 out of every 1000 humans born suffer from some genetic or partly-genetic condition requiring medical attention at some time. It has been estimated that approximately 1 person in every 2000 born carry a deleterious genetic mutation that was caused by the continued exposure of many generations of our ancestors to natural background radiation. On the same basis, it is predicted that the incidence of genetic diseases would be increased to 106 per 1000 in the children and grandchildren of radiation workers who were exposed to 1 rem per year commencing at age 18. However, there was no detectable change in the health and fitness of mice whose male ancestors were repeatedly exposed to high radiation doses up to 900 rem per generation. (auth)

  20. Anti-apoptotic effects of Z alpha1-antitrypsin in human bronchial epithelial cells.

    LENUS (Irish Health Repository)

    Greene, C M

    2010-05-01

    alpha(1)-antitrypsin (alpha(1)-AT) deficiency is a genetic disease which manifests as early-onset emphysema or liver disease. Although the majority of alpha(1)-AT is produced by the liver, it is also produced by bronchial epithelial cells, amongst others, in the lung. Herein, we investigate the effects of mutant Z alpha(1)-AT (ZAAT) expression on apoptosis in a human bronchial epithelial cell line (16HBE14o-) and delineate the mechanisms involved. Control, M variant alpha(1)-AT (MAAT)- or ZAAT-expressing cells were assessed for apoptosis, caspase-3 activity, cell viability, phosphorylation of Bad, nuclear factor (NF)-kappaB activation and induced expression of a selection of pro- and anti-apoptotic genes. Expression of ZAAT in 16HBE14o- cells, like MAAT, inhibited basal and agonist-induced apoptosis. ZAAT expression also inhibited caspase-3 activity by 57% compared with control cells (p = 0.05) and was a more potent inhibitor than MAAT. Whilst ZAAT had no effect on the activity of Bad, its expression activated NF-kappaB-dependent gene expression above control or MAAT-expressing cells. In 16HBE14o- cells but not HEK293 cells, ZAAT upregulated expression of cIAP-1, an upstream regulator of NF-kappaB. cIAP1 expression was increased in ZAAT versus MAAT bronchial biopsies. The data suggest a novel mechanism by which ZAAT may promote human bronchial epithelial cell survival.

  1. Sequential nearest-neighbor effects on computed {sup 13}C{sup {alpha}} chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Vila, Jorge A. [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States); Serrano, Pedro; Wuethrich, Kurt [The Scripps Research Institute, Department of Molecular Biology (United States); Scheraga, Harold A., E-mail: has5@cornell.ed [Cornell University, Baker Laboratory of Chemistry and Chemical Biology (United States)

    2010-09-15

    To evaluate sequential nearest-neighbor effects on quantum-chemical calculations of {sup 13}C{sup {alpha}} chemical shifts, we selected the structure of the nucleic acid binding (NAB) protein from the SARS coronavirus determined by NMR in solution (PDB id 2K87). NAB is a 116-residue {alpha}/{beta} protein, which contains 9 prolines and has 50% of its residues located in loops and turns. Overall, the results presented here show that sizeable nearest-neighbor effects are seen only for residues preceding proline, where Pro introduces an overestimation, on average, of 1.73 ppm in the computed {sup 13}C{sup {alpha}} chemical shifts. A new ensemble of 20 conformers representing the NMR structure of the NAB, which was calculated with an input containing backbone torsion angle constraints derived from the theoretical {sup 13}C{sup {alpha}} chemical shifts as supplementary data to the NOE distance constraints, exhibits very similar topology and comparable agreement with the NOE constraints as the published NMR structure. However, the two structures differ in the patterns of differences between observed and computed {sup 13}C{sup {alpha}} chemical shifts, {Delta}{sub ca,i}, for the individual residues along the sequence. This indicates that the {Delta}{sub ca,i} -values for the NAB protein are primarily a consequence of the limited sampling by the bundles of 20 conformers used, as in common practice, to represent the two NMR structures, rather than of local flaws in the structures.

  2. Effects of radiations on electronic components - Course IN2P3, release 6

    International Nuclear Information System (INIS)

    2007-01-01

    As many off-the-shelf electronic components are now present onboard satellites, launchers and planes, this course proposes an overview of effects radiations can have on these components, notably in space applications. A first part proposes an overview of radiative environments, and more particularly presents the space radiative environment (solar wind, solar flares, cosmic radiation, radiation belts). It also presents the atmospheric and Earth radiative environment due to cosmic radiation, the alpha radiation (origin of particles, particle flow), the radiative environment within an accelerator. The second part addresses the effects of these radiative environments on electronic components, and the associated standards and tests. It addresses cumulative effects and proposes a detailed analysis of the effects of an ionizing dose on a MOS transistor, an analysis of the effects of ionising dose rate on a bipolar NPN or PNP vertical or lateral transistor, an analysis of the effects of atomic displacements, and a discussion of structure modifications. The next part describes various single events: the Single Event Upset (SEU) and the Multiple Bit Upset (MBU) in the case of a SRAM, the SEL (Single Event Latch-up) phenomenon, the SEGR (Single Event Gate Rupture) phenomenon in the case of a Power MOSFET, and the SEB (Single Event Burnout) phenomenon in the case of a Power MOSFET

  3. Modification of genetic effects of gamma radiation by laser radiation

    International Nuclear Information System (INIS)

    Khotyljova, L.V.; Khokhlova, S.A.; Khokhlov, I.V.

    1988-01-01

    Full text: Mutants obtained by means of ionizing radiation and chemical mutagens often show low viability and productivity that makes their use in plant breeding difficult. Methods reducing the destructive mutagen action on important functions of plant organism and increasing quality and practical value of induced mutants would be interesting. We believe that one method for increasing efficiency of experimental mutagenesis in plants is the application of laser radiation as a modificator of genetic effects of ionizing radiation and chemical mutagens. Combined exposure of wheat seedlings to a gamma radiation dose of 2 kR and to laser radiation with the wave length of 632.8 nm (power density - 20 mVt/cm 2 , exposure - 30 min.) resulted in reducing the chromosomal aberration percentage from 30.5% in the gamma version to 16.3% in the combined treatment version. A radiosensibilizing effect was observed at additional exposure of gamma irradiated wheat seeds to laser light with the wave length of 441.6 nm where chromosomal aberration percentage increased from 22% in the gamma-irradiation version to 31% in the combined treatment version. By laser radiation it is also possible to normalize mitotic cell activity suppressed by gamma irradiation. Additional seedling irradiation with the light of helium-neon laser (632.8 nm) resulted in recovery of mitotic cell activity from 21% to 62% and increasing the average content of DNA per nucleus by 10%. The influence of only laser radiation on plant variability was also studied and it was shown that irradiation of wheat seeds and seedlings with pulsed and continuous laser light of visible spectrum resulted in phenotypically altered forms in M 2 . Their frequencies was dependent upon power density, dose and radiation wave length. Number of altered forms increased in going from long-wave to short-wave spectrum region. In comparing efficiency of different laser types of pulsed and continuous exposure (dose - 180 J/cm 2 ) 2% of altered

  4. Radiation effects on light sources and detectors

    International Nuclear Information System (INIS)

    Barnes, C.E.

    1985-01-01

    The rapidly expanding field of optoelectronics includes a wide variety of both military and non-military applications in which the systems must meet radiation exposure requirements. Herein, we review the work on radiation effects on sources and detectors for such optoelectronic systems. For sources the principal problem is permanent damage-induced light output degradation, while for detectors it is ionizing radiation-induced photocurrents

  5. Field methods for determining contents of alpha-radiating nuclides on the areas contaminated with depositions after the Chernobyl nuclear power station failure

    International Nuclear Information System (INIS)

    Pitkevich, V.A.; Duba, V.V.

    1992-01-01

    The work is aimed at creating field methods for estimating contents of alpha-radiating nuclides on the areas contaminated with depositions after the Chernobyl' station failure and for measuring the density of alpha-particles flux at various depths of soil. The methods make it possible to estimate the character of migration of isotopes Pu in depth. Instrumental and physical grounding of the methods are given. One can find the results of field measurements of α-active nuclides content in depositions. The results of measurement prove theoretical and practical feasibility of the suggested methods. 2 refs.; 4 figs.; 1 tabs

  6. The acute effects of alpha and beta irradiation of mouse skin and the factors affecting the response

    International Nuclear Information System (INIS)

    Needham, S.G.; Coggle, J.E.

    1991-01-01

    Several problems regarding acute effects of alpha and beta irradiation were investigated in order to clarify protection problems of localised doses to the skin. A study into the acute biological effects of different energy beta emitters and the effects of energy and area on the response showed direct relationships between these criteria for a range of different acute responses with different time courses. Three different types of acute response were found and these are described as 'moist desquamation', 'acute ulceration' and 'acute epidermal necrosis'. An unexpected finding was that the lower energy beta emitter 170 Tm was as efficient at inducing scab formation as the higher energy 90 Sr sources for the same area of exposure. Experiments using 2x4 cm 2 exposures to 224 Cm alpha particles showed that the response to this poorly penetrating radiation was minimal after doses as high as 180 Gy measured at 10 μm into the skin. In comparison, large area exposure to 170 Tm produced areas of prolonged scabbing after doses up to 100 Gy. However, the intensity of the reaction varied between strains. (author)

  7. Influence of thermal barrier effect of grain boundaries on bulk cascades in alpha-zirconium revealed by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Yanan; Lai, Wensheng, E-mail: wslai@tsinghua.edu.cn

    2016-03-15

    The effect of grain boundaries (GBs) on bulk cascades in nano-structured alpha-zirconium has been studied by molecular dynamics (MD) simulations. It turns out that the existence of GBs increases the defect productivity in grains, suggesting that the GBs may act as a thermal barrier and postpone the annihilation of defects within grains. Moreover, it is found that the thermal barrier effect of GBs facilitates the shift of symmetric tilt GBs to the grain with higher temperature, and the smaller the tilt angle is, the easier the boundary shift will be. Thus, the influence of GBs on radiation damage in the nano-structured materials comes from the competition between damage increase in grains and defect annihilation at GBs.

  8. Theoretical and experimental radiation effectiveness of the free radical dosimeter alanine to irradiation with heavy charged particles

    DEFF Research Database (Denmark)

    Hansen, Jørgen-Walther; Olsen, K. J.

    1985-01-01

    Dose-response characteristics have been measured for the crystalline amino acid L-.alpha.-alanine irradiated with ion beams of 6 and 16 MeV protons, 20 MeV .alpha. particles, 21 MeV7Li ions, 64 MeV16O ions, and 80 MeV32S ions. The experimental radiation effectiveness (RE) with reference to low-LE...

  9. Effects of ionizing radiation on cryogenic infrared detectors

    Science.gov (United States)

    Moseley, S. H.; Silverberg, R. F.; Lakew, B.

    1989-01-01

    The Diffuse Infrared Background Experiment (DIRBE) is one of three experiments to be carried aboard the Cosmic Background Explorer (COBE) satellite scheduled to be launched by NASA on a Delta rocket in 1989. The DIRBE is a cryogenic absolute photometer operating in a liquid helium dewar at 1.5 K. Photometric stability is a principal requirement for achieving the scientific objectives of this experiment. The Infrared Astronomy Satellite (IRAS), launched in 1983, which used detectors similar to those in DIRBE, revealed substantial changes in detector responsivity following exposure to ionizing radiation encountered on passage through the South Atlantic Anomaly (SAA). Since the COBE will use the same 900 Km sun-synchronous orbit as IRAS, ionizing radiation-induced performance changes in the detectors were a major concern. Here, ionizing radiation tests carried out on all the DIRBE photodetectors are reported. Responsivity changes following exposure to gamma rays, protons, and alpha particle are discussed. The detector performance was monitored following a simulated entire mission life dose. In addition, the response of the detectors to individual particle interactions was measured. The InSb photovoltaic detectors and the Blocked Impurity Band (BIB) detectors revealed no significant change in responsivity following radiation exposure. The Ge:Ga detectors show large effects which were greatly reduced by proper thermal annealing.

  10. Radiation-induced bystander effect: The important part of ionizing radiation response. Potential clinical implications

    Directory of Open Access Journals (Sweden)

    Maria Wideł

    2009-08-01

    Full Text Available It has long been a central radiobiological dogma that the damaging effects of ionizing radiation, such as cell death, cytogenetic changes, apoptosis, mutagenesis, and carcinogenesis, are the results of the direct ionization of cell structures, particularly DNA, or indirect damage via water radiolysis products. However, several years ago attention turned to a third mechanism of radiation, termed the “bystander effect” or “radiation-induced bystander effect” (RIBE. This is induced by agents and signals emitted by directly irradiated cells and manifests as a lowering of survival, cytogenetic damage, apoptosis enhancement, and biochemical changes in neighboring non-irradiated cells. The bystander effect is mainly observed in in vitro experiments using very low doses of alpha particles (range; mGy, cGy, but also after conventional irradiation (X-rays, gamma rays at low as well as conventional doses. The mechanisms responsible for the bystander effect are complex and still poorly understood. It is believed that molecular signals released from irradiated cells induce different signaling ways in non-irradiated neighboring cells, leading to the observed events. The molecular signals may be transmitted through gap junction intercellular communication and through a medium transfer mechanism. The nature of these transmitted factors are diverse, and still not defi nitely established. It seems that RIBE may have important clinical implications for health risk associated with radiation exposure. Potentially, this effectmay have important implications in the creation of whole-body or localized side effects in tissues beyond the irradiation fi eld and also in low-dose radiological and radioisotope diagnostics. Factors emitted by irradiated cells may result in the risk of genetic instability, mutations, and second primary cancer induction. They might also have their own part in inducing and extending post-radiation side effects in normal tissue. The

  11. Bystander Effects of Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B. [Harvard T.H. Chan School of Public Health, Boston, MA (United States). Dept. of Genetics and Complex Diseases

    2017-01-17

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low-dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  12. Bystander Effects of Ionizing Radiation

    International Nuclear Information System (INIS)

    Little, John B.

    2017-01-01

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low-dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  13. Chernobyl health effects: radiation or stress?

    International Nuclear Information System (INIS)

    Grinkhal', G.

    1996-01-01

    Consideration is given to results of wide-scale examination of human population, subjected to the effect of radiation in result of Chernobyl accident. The examined contingents consisted of liquidators, evacuated from 30-km zone, people still living in contamination territories, children of irradiated parents and children, who received large radiation doses. High levels of respiratory system diseases, digestive system diseases, cardiovascular diseases and nervous system diseases were revealed for these people. It was revealed that stress, socio-economic and chemical factors played sufficient role in disease incidence. It is shown that fair of radiation may damage more, than radiation itself

  14. Late effects of radiation: host factors

    International Nuclear Information System (INIS)

    Fry, R.J.M.; Storer, J.B.

    1983-01-01

    The paper discusses the influence of host factors on radiation late effects and in particular cancer. Radiation induces cellular changes that result in initiated cells with a potential to become cancers. The expression of the initiated cells as tumors is influenced, if not determined, by both tissue and systemic factors that are sex-, age-, and species-dependent

  15. Biological radiation effects and radioprotection standards

    International Nuclear Information System (INIS)

    Clerc, H.

    1991-03-01

    In this report, after recalling the mode of action of ionizing radiations, the notions of dose, dose equivalents and the values of natural irradiation, the author describes the biological radiation effects. Then he presents the ICRP recommendations and their applications to the french radioprotection system

  16. Radiation effects on Fischer-Tropsch syntheses

    International Nuclear Information System (INIS)

    Hatada, M.; Matsuda, K.

    1977-01-01

    Radiation effects on Fischer-Tropsch synthesis has been examined using high dose rate electron beams and Fe-Cu-diatomaceous earth catalyst. Yields of saturated hydrocarbons were found to increase by irradiation, but the yields of these compounds were decreased by raising reaction temperature without irradiation, suggesting the presence of radiation chemical process in catalytic reactions. (author)

  17. Radiation effects in charge coupled devices

    International Nuclear Information System (INIS)

    Williams, R.A.; Nelson, R.D.

    1975-01-01

    Charge coupled devices (CCD s) exhibit a number of advantages (low cost, low power, high bit density) in their several applications (serial memories, imagers, digital filters); however, fairly elementary theoretical considerations indicate that they will be very vulnerable to permanent radiation damage, by both neutrons and ionizing radiation, and to transient upset by pulsed ionizing radiation. Although studies of permanent ionizing-radiation damage in CCD's have been reported, little information has been published concerning their overall nuclear radiation vulnerability. This paper presents a fairly comprehensive experimental study of radiation effects in a 256-cell surface-channel, CCD shift-register. A limited amount of similar work is also presented for a 128-cell surface-channel device and a 130 cell peristaltic CCD shift register. The radiation effects phenomena discussed herein, include transient-ionizing-radiation responses, permanent ionizing- radiation damage to transfer efficiency, charge-carrying capacity and input transfer gate bias, and neutron damage to storage time--determined from dark current and charge-up time measurements

  18. Effect of ascorbic acid and alpha-tocopherol supplementations on serum leptin, tumor necrosis factor alpha, and serum amyloid A levels in individuals with type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Mostafa Jamalan

    2015-10-01

    Full Text Available Objective: Diabetes mellitus Type 2 is one of the most widespread chronic metabolic diseases. In most cases, this type of diabetes is associated with alterations in levels of some inflammatory cytokines and hormones. Considering anti-inflammatory properties of plant extracts rich in ascorbic acid (vitamin C and alpha-tocopherol (vitamin E, anti-diabetic properties of these two well-known antioxidant vitamins were investigated through measurement of serum levels of high-sensitivity C-reactive protein (hs-CRP, insulin, leptin, tumor necrosis factor alpha (TNF-α, and serum amyloid A (SAA in patients with diabetes mellitus type 2. Methods: Male patients (n=80 were randomly divided into two groups each consisted of 40 subjects. Test groups were supplemented with ascorbic acid (1000 mg/day or alpha-tocopherol (300 mg/day orally during four weeks. Before and after treatment, serum biochemical factors of subjects were measured and compared. Results: Our results showed that both ascorbic acid and alpha-tocopherol could induce significant anti-inflammatory effects by decreasing the level of inflammatory factors such as TNF-α, SAA, and hs-CRP in diabetes mellitus type 2 patients. Effects of alpha-tocopherol and ascorbic acid in decreasing serum leptin level were similar. Ascorbic acid in contrast to alpha-tocopherol diminished fasting insulin and HOMA index but had no effect on LDL serum level. Conclusion: Concerning the obtained results, it is concluded that consumption of supplementary vitamins C and E could decrease induced inflammatory response in patients with diabetes mellitus type 2.  It is also possible that vitamin C and vitamin E supplementation can attenuate incidence of some proposed pathological effects of diabetes mellitus.

  19. Effect of alpha drift and instabilities on tokamak plasma edge conditions

    International Nuclear Information System (INIS)

    Miley, G.H.; Choi, C.K.

    1983-01-01

    As suprathermal fusion products slow down in a Tokamak, their average drift is inward. The effect of this drift on the alpha heating and thermalization profiles is examined. In smaller TFTR-type devices, heating in the outer region can be cut in half. Also, the fusion-product energy-distribution near the plasma edge has a positive slope with increasing energy, representing a possible driving mechanism for micro-instabilities. Another instability that can seriously affect outer plasma conditions and shear Alfven transport of alphas is also considered

  20. Coherence effects in radiative scattering

    International Nuclear Information System (INIS)

    Knoll, J.; Lenk, R.

    1993-03-01

    The bremsstrahl-production of photons in dense matter is reinvestigated using the example of an exactly solvable quantum mechanical model in one space dimension. Coherence phenomena between successive radiative scatterings among the constituents lead to a modification of the production cross section in the medium relative to the incoherent quasi-free prescription used in kinetic models. Analytic expressions for the correction factor have been derived comparing the quantum rates with the corresponding incoherent quasi-free rates. The result has implications for the kinetic description of all kinds of radiative processes in nucleus-nucleus collisions, both on the level of hadron and parton dynamics. (orig.)

  1. Regulatory aspects of the transport of high radiation level and alpha waste in France

    International Nuclear Information System (INIS)

    Devillers, C.; Grenier, M.; Lombard, J.; Mathieu, F.

    1993-01-01

    The introduction of the 10 mSv.h -1 at 3 m limit for LSA unshielded material makes it impossible to transport, as LSA material, the highest radiation level wastes from EdF PWR's operations. At present, the EdF's waste blocks can be transported as LSA III material by special arrangement. A new package design, equivalent to a Type B package, will be available for their transport before the end of the year 1995. It consists of a re-usable steel cylinder over-packing each block. Compliance of this package model with transport safety requirements will be demonstrated by taking into account the non-dispersability, as LSA III material, of the irradiating waste. A two-step approach has been accepted by the French Competent Authority for the transport of these wastes: (1) a specific ISO 20 container, thermally insulated, can be used by special arrangement for the transport of LSA combustible material having a total activity per conveyance higher than 100 A2. Furthermore, additional safety measures have to be implemented for these consignments. (2) After the end of 1995, a Type B package must be used for activity contents per conveyance higher than 100 A2. A specific 20' ISO container, complying with Type B requirements, is being developed for that purpose. (author)

  2. Alpha-radiator distribution in the skin and body for contamination of various types

    International Nuclear Information System (INIS)

    Khodyreva, M.A.; Sit'ko, R.Ya.; Simakov, A.V.; Andreeva, N.A.

    1977-01-01

    To evaluate the hazard of skin contamination with dry salts of α-radiators ( 210 Po, 241 Am and 237 Np) and their solutions, experiments have been made on sucking-pigs, whose skin by its morphological and functional features resembles that of a man. It has been found that after 6-hour contact in the absence of sanitary treatment, the distribution of the radionuclides in the upper layer of the skin (100 μm) is practically the same for both kinds of contamination. In deeper skin layers and in the organism the content of nuclides studied deposited in the form of the dry salts is 1.5-7 times higher in comparison with the skin and organism contamination with a solution which is connected with the pH value of contaminant. The results obtained probe the necessity of proper hand skin protection in activities with 210 Po and transplutonium elements and that of early skin decontamination, no matter what kind of contamination is

  3. Physics of radiation effects in crystals

    CERN Document Server

    Johnson, RA

    1986-01-01

    ``Physics of Radiation Effects in Crystals'' is presented in two parts. The first part covers the general background and theory of radiation effects in crystals, including the theory describing the generation of crystal lattice defects by radiation, the kinetic approach to the study of the disposition of these defects and the effects of the diffusion of these defects on alloy compositions and phases. Specific problems of current interest are treated in the second part and include anisotropic dimensional changes in x-uranium, zirconium and graphite, acceleration of thermal creep in reactor ma

  4. Effects of radiation on scintillating fiber performance

    International Nuclear Information System (INIS)

    Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Young, K.G.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Parr, H.

    1992-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain needed information and calculational procedures used in performing predications for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. These calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented

  5. Effects of radiation on scintillating fiber performance

    International Nuclear Information System (INIS)

    Young, K.G.; Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Paar, H.

    1993-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain desired information and calculational procedures used in performing predictions for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. The calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented

  6. Characteristics of natural background external radiation and effective dose equivalent

    International Nuclear Information System (INIS)

    Fujimoto, Kenzo

    1989-01-01

    The two sources of natural radiation - cosmic rays and primordial radionuclides - are described. The factors affecting radiation doses received from natural radiation and the calculation of effective dose equivalent due to natural radiation are discussed. 10 figs., 3 tabs

  7. The time-course of alpha neurofeedback training effects in healthy participants

    NARCIS (Netherlands)

    Dekker, M.K.J.; Sitskoorn, M.M.; Denissen, A.; van Boxtel, G.J.M.

    2014-01-01

    The time-course of alpha neurofeedback training (NFT) was investigated in 18 healthy participants who received 15 sessions of training (eyes open), each consisting of three training periods (data are from Van Boxtel et al., 2012). Here we report on the within- and between-session training effects

  8. A Comparative Study of Effects of Omega‑3 Fatty Acids, Alpha Lipoic ...

    African Journals Online (AJOL)

    Background: Diabetes Mellitus is a metabolic disorder characterized by abnormal lipid and glucose metabolism. Various modes of adjuvant therapy have been advocated to ameliorate insulin resistance. Aim: This study was intended to assess the effects of antioxidants; alpha lipoic acid (ALA), omega 3 fatty acid and vitamin ...

  9. Alpha particle effects as a test domain for PAP, a Plasma Apprentice Program

    International Nuclear Information System (INIS)

    Mynick, H.E.

    1987-01-01

    A new type of computational tool under development, employing techniques of symbolic computation and artificial intelligence to automate as far as possible the research activities of a human plasma theorist, is described. Its present and potential uses are illustrated using the area of the theory of alpha particle effects in fusion plasmas as a sample domain. (orig.)

  10. Effect of hypoxia-inducible factor 1-alpha (HIF-1α) on proliferation ...

    African Journals Online (AJOL)

    Jane

    2011-07-25

    Jul 25, 2011 ... Full Length Research Paper. Effect of hypoxia-inducible factor 1-alpha ... 1Department of Neurosurgery, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025,. China. 2Department of Neurosurgery, Chaoyang Hospital, Huainan, Anhui, China. 3Department of Neurosurgery ...

  11. Effects of L-ascorbic acid and alpha-tocopherol on biochemical ...

    African Journals Online (AJOL)

    Background: The purpose of this study is to determine the effect of L-ascorbic acid and alpha-tocopherol as well as combination of these vitamins with or without exposure to physical exercise on intensity of lipid peroxidation, activity of xanthine oxidase, activity of total antioxidative system, concentration of glutathione, and ...

  12. Prevention and Treatment of Functional and Structural Radiation Injury in the Rat Heart by Pentoxifylline and Alpha-Tocopherol

    International Nuclear Information System (INIS)

    Boerma, Marjan; Roberto, Kerrey A.; Hauer-Jensen, Martin

    2008-01-01

    Purpose: Radiation-induced heart disease (RIHD) is a severe side effect of thoracic radiotherapy. This study examined the effects of pentoxifylline (PTX) and α-tocopherol on cardiac injury in a rat model of RIHD. Methods and Materials: Male Sprague-Dawley rats received fractionated local heart irradiation with a daily dose of 9 Gy for 5 days and were observed for 6 months after irradiation. Rats were treated with a combination of PTX, 100 mg/kg/day, and α-tocopherol (20 IU/kg/day) and received these compounds either from 1 week before until 6 months after irradiation or starting 3 months after irradiation, a time point at which histopathologic changes become apparent in our model of RIHD. Results: Radiation-induced increases in left ventricular diastolic pressure (in mm Hg: 35 ± 6 after sham-irradiation, 82 ± 11 after irradiation) were significantly reduced by PTX and α-tocopherol (early treatment: 48 ± 7; late treatment: 53 ± 6). PTX and α-tocopherol significantly reduced deposition of collagen types I (radiation only: 3.5 ± 0.2 μm 2 per 100 μm 2 ; early treatment: 2.7 ± 0.8; late treatment: 2.2 ± 0.2) and III (radiation only: 13.9 ± 0.8; early treatment: 11.0 ± 1.2; late treatment: 10.6 ± 0.8). On the other hand, radiation-induced alterations in heart/body weight ratios, myocardial degeneration, left ventricular mast cell densities, and most echocardiographic parameters were not significantly altered by PTX and α-tocopherol. Conclusions: Treatment with PTX and α-tocopherol may have beneficial effects on radiation-induced myocardial fibrosis and left ventricular function, both when started before irradiation and when started later during the process of RIHD

  13. Overview of radiation effects research in photonics

    Science.gov (United States)

    Webb, Robert C.; Cohn, Lewis M.; Taylor, Edward W.; Greenwell, Roger A.

    1995-05-01

    A brief overview of ongoing radiation effects research in photonics is presented focusing on integrated optic and acousto-optic components. A short summary of radiation-induced effects in electro-optic modulators, detector arrays, and other photonic technologies is presented along with extensive references. The coordinated radiation effects studies among researchers within the Tri-Service Organizations and international experimental teams are beginning to demonstrate consistent measurements of radiation-induced effects in photonic components and confirming earlier reported data. This paper will present an overview of these coordinated investigations and focus on key research being conducted with the AFMC Phillips Laboratory, Naval Research Laboratory, Defence Nuclear Agency, NATO Nuclear Effects Task Group, and the Tri-Service Photonics Coordinating Committee.

  14. Effects of small radiation doses

    International Nuclear Information System (INIS)

    Fuchs, G.

    1986-01-01

    The term 'small radiation dosis' means doses of about (1 rem), fractions of one rem as well as doses of a few rem. Doses like these are encountered in various practical fields, e.g. in X-ray diagnosis, in the environment and in radiation protection rules. The knowledge about small doses is derived from the same two forces, on which the radiobiology of human beings nearly is based: interpretation of the Hiroshima and Nagasaki data, as well as the experience from radiotherapy. Careful interpretation of Hiroshima dates do not provide any evidence that small doses can induce cancer, fetal malformations or genetic damage. Yet in radiotherapy of various diseases, e.g. inflammations, doses of about 1 Gy (100 rad) do no harm to the patients. According to a widespread hypothesis even very small doses may induce some types of radiation damage ('no threshold'). Nevertheless an alternative view is justified. At present no decision can be made between these two alternatives, but the usefullness of radiology is definitely better established than any damage calculated by theories or extrapolations. Based on experience any exaggerated fear of radiations can be met. (author)

  15. Effect of radiation processing on meat tenderisation

    International Nuclear Information System (INIS)

    Kanatt, Sweetie R.; Chawla, S.P.; Sharma, Arun

    2015-01-01

    The effect of radiation processing (0, 2.5, 5 and 10 kGy) on the tenderness of three types of popularly consumed meat in India namely chicken, lamb and buffalo was investigated. In irradiated meat samples dose dependant reduction in water holding capacity, cooking yield and shear force was observed. Reduction in shear force upon radiation processing was more pronounced in buffalo meat. Protein and collagen solubility as well as TCA soluble protein content increased on irradiation. Radiation processing of meat samples resulted in some change in colour of meat. Results suggested that irradiation leads to dose dependant tenderization of meat. Radiation processing of meat at a dose of 2.5 kGy improved its texture and had acceptable odour. - Highlights: • Effect of radiation processing on tenderness of three meat systems was evaluated. • Dose dependant reduction in shear force seen in buffalo meat. • Collagen solubility increased with irradiation

  16. Effects of gamma radiation in tomato seeds

    Energy Technology Data Exchange (ETDEWEB)

    Wiendl, Toni A.; Wiendl, Fritz W.; Franco, Suely S.H.; Franco, Jose G.; Althur, Valter, E-mail: tawiendl@hotmail.com, E-mail: gilmita@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Arthur, Paula B., E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2013-07-01

    Tomato dry seeds of the hybrid 'Gladiador' F1 were exposed to low doses of gamma radiation from Co-60 source at 0,509 kGy tax rate in order to study stimulation effects of radiation on germination and plant growth. Eight treatments radiation doses were applied as follows: 0 (control); 2,5; 5,0; 7,5; 10,0; 12,5; 15,0; 20,0 Gy. Seed germination as well as green fruits number, harvested fruit number, fruit weight and total production were assessed to identify occurrence of stimulation. Tomato seeds and plants were handled as for usual tomato production in Brazil. Low doses of gamma radiation treatment in the seeds stimulate germination and substantially increase fruit number and total production up to 86% at 10 Gy dose. There are evidences that the use of low doses of gamma radiation can stimulate germination and plant production thus, showing hormetic effects. (author)

  17. Radiation effect on rocket engine performance

    Science.gov (United States)

    Chiu, Huei-Huang; Kross, K. W.; Krebsbach, A. N.

    1990-01-01

    Critical problem areas involving the effect of radiation on the combustion of bipropellants are addressed by formulating a universal scaling law in combination with a radiation-enhanced vaporization combustion model. Numerical algorithms are developed and data pertaining to the Variable Thrust Engine (VTE) and the Space Shuttle Main Engine (SSME) are used to conduct parametric sensitivity studies to predict the principal intercoupling effects of radiation. The analysis reveals that low-enthalpy engines, such as the VTE, are vulnerable to a substantial performance setback due to radiative loss, whereas the performance of high-enthalpy engines such as the SSME are hardly affected over a broad range of engine operation. Combustion enhancement by radiative heating of the propellant has a significant impact on propellants with high absorptivity.

  18. Effects of gamma radiation in tomato seeds

    International Nuclear Information System (INIS)

    Wiendl, Toni A.; Wiendl, Fritz W.; Franco, Suely S.H.; Franco, Jose G.; Althur, Valter; Arthur, Paula B.

    2013-01-01

    Tomato dry seeds of the hybrid 'Gladiador' F1 were exposed to low doses of gamma radiation from Co-60 source at 0,509 kGy tax rate in order to study stimulation effects of radiation on germination and plant growth. Eight treatments radiation doses were applied as follows: 0 (control); 2,5; 5,0; 7,5; 10,0; 12,5; 15,0; 20,0 Gy. Seed germination as well as green fruits number, harvested fruit number, fruit weight and total production were assessed to identify occurrence of stimulation. Tomato seeds and plants were handled as for usual tomato production in Brazil. Low doses of gamma radiation treatment in the seeds stimulate germination and substantially increase fruit number and total production up to 86% at 10 Gy dose. There are evidences that the use of low doses of gamma radiation can stimulate germination and plant production thus, showing hormetic effects. (author)

  19. Biological effects of proton radiation: an update

    International Nuclear Information System (INIS)

    Girdhani, S.; Hlatky, L.; Sachs, R.

    2015-01-01

    Proton radiation provides significant dosimetric advantages when compared with gamma radiation due to its superior energy deposition characteristics. Although the physical aspects of proton radiobiology are well understood, biological and clinical endpoints are understudied. The current practice to assume the relative biological effectiveness of low linear energy transfer (LET) protons to be a generic value of about 1.1 relative to photons likely obscures important unrecognised differentials in biological response between these radiation qualities. A deeper understanding of the biological properties induced by proton radiation would have both radiobiological and clinical impact. This article briefly points to some of the literature pertinent to the effects of protons on tissue-level processes that modify disease progression, such as angiogenesis, cell invasion and cancer metastasis. Recent findings hint that proton radiation may, in addition to offering improved radio-therapeutic targeting, be a means to provide a new dimension for increasing therapeutic benefits for patients by manipulating these tissue-level processes. (authors)

  20. Evaluation of GABAergic neuroactive steroid 3alpha-hydroxy-5alpha-pregnane-20-one as a neurobiological substrate for the anti-anxiety effect of ethanol in rats.

    Science.gov (United States)

    Hirani, Khemraj; Sharma, Ajay N; Jain, Nishant S; Ugale, Rajesh R; Chopde, Chandrabhan T

    2005-07-01

    Acute systemic ethanol administration is known to elevate plasma and cerebral levels of neuroactive steroid 3alpha-hydroxy-5alpha-pregnane-20-one (3alpha, 5alpha-THP; allopregnanolone) to a concentration sufficient to potentiate GABA(A) receptors. We have earlier demonstrated that 3alpha, 5alpha-THP mediates the antidepressant-like effect of ethanol in Porsolt forced swim test. The aim of the present study is to explain the relationship between endogenous GABAergic neurosteroids and anxiolytic effect of ethanol in Sprague-Dawley rats. The mediation of 3alpha, 5alpha-THP in the anti-anxiety effect of ethanol was assessed by pharmacological interactions of ethanol with various endogenous neurosteroidal modulators and using simulated physiological conditions of altered neurosteroid content in elevated plus maze (EPM) test. Pretreatment of 3alpha, 5alpha-THP (0.5-2.5 mug/rat, i.c.v.) or neurosteroidogenic agents such as 3alpha, 5alpha-THP precursor progesterone (5 or 10 mg/kg, i.p.), 11-beta hydroxylase inhibitor metyrapone (50 or 100 mg/kg, i.p.) or the GABA(A) receptor agonist muscimol (25 ng/rat, i.c.v.) significantly potentiated the anti-anxiety effect of ethanol (1 g/kg, i.p.). On the other hand, the GABAergic antagonistic neurosteroid dehydroepiandrosterone sulphate (DHEAS) (1 mg/kg, i.p.), the GABA(A) receptor blocker bicuculline (1 mg/kg, i.p.), the 5alpha-reductase inhibitor finasteride (50 x 2 mg/kg, s.c.) or the mitochondrial diazepam binding inhibitory receptor antagonist PK11195 (1 mg/kg, i.p.) reduced ethanol-induced preference of time spent and number of entries into open arms. Anti-anxiety effect of ethanol was abolished in adrenalectomized (ADX) rats as compared to sham-operated control. This ADX-induced blockade was restored by prior systemic injection of progesterone, signifying the contribution of peripheral steroidogenesis in ethanol anxiolysis. Socially isolated animals known to exhibit decreased brain 3alpha, 5alpha-THP and GABA(A) receptor

  1. The effects of ionizing radiation on man

    International Nuclear Information System (INIS)

    Watson, G.M.

    1975-08-01

    This paper describes the major effects of ionizing radiation on man and the relationship between such effects and radiation dose, with the conclusion that standards of radiological safety must be based on the carcinogenetic and mutagenic properties of ionizing radiation. Man is exposed to radiation from natural sources and from man-made sources. Exposure from the latter should be regulated but, since there is little observational or experimental evidence for predicting the effects of the very small doses likely to be required for adequate standards of safety, it is necessary to infer them from what is seen at high doses. Because the formal relationship between dose and effect is not fully understood, simplifying assumptions are necessary to estimate the effects of low doses. Two such assumptions are conventionally used; that there is a linear relationship between dose and effect at all levels of dose, and that the rate at which a dose of radiation is given does not alter the magnitude of the effect. These assumptions are thought to be conservative, that is they will not lead to an underestimation of the effects of small radiation doses although they may give an over-estimate. (author)

  2. Fast Neutron Radiation Effects on Bacillus Subtili

    International Nuclear Information System (INIS)

    Chen Xiaoming; Zhang Jianguo; Chu Shijin; Ren Zhenglong; Zheng Chun; Yang Chengde; Tan Bisheng

    2009-01-01

    To examine the sterilizing effect and mechanism of neutron radiation, Bacillus subtilis var. niger. strain (ATCC 9372) spores were irradiated with the fast neutron from the Chinese fast burst reactor II(CFBR-II). The plate-count results indicated that the D 10 value was 384.6 Gy with a neutron radiation dose rate of 7.4 Gy/min. The rudimental catalase activity of the spores declined obviously with the increase in the radiation dose. Meanwhile, under the scanning electron microscope, no visible influence of the neutron radiation on the spore configuration was detected even if the dose was increased to 4 kGy. The content and distribution of DNA double-strand breaks induced by neutron radiation at different doses were measured and quantified by pulsed-field gel electrophoresis (PFGE). Further analysis of the DNA release percentage (PR), the DNA breakage level (L), and the average molecular weight, indicated that DNA fragments were obviously distributed around the 5 kb regions at different radiation doses, which suggests that some points in the DNA molecule were sensitive to neutron radiation. Both PR and L varied regularly to some extent with the increase in radiation dose. Thus neutron radiation has a high sterilization power, and can induce falling enzyme activity and DNA breakage in Bacillus subtilis spores

  3. Radiative effects of global MODIS cloud regimes

    Science.gov (United States)

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji

    2018-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations. PMID:29619289

  4. Radiative Effects of Global MODIS Cloud Regimes

    Science.gov (United States)

    Oraiopoulos, Lazaros; Cho, Nayeong; Lee, Dong Min; Kato, Seiji

    2016-01-01

    We update previously published MODIS global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 dataset. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux datasets. Our results clearly show the CRs are radiatively distinct in terms of shortwave, longwave and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance datasets suffering from imperfect spatiotemporal matching depend on CR, and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations.

  5. Predicted solar cell edge radiation effects

    International Nuclear Information System (INIS)

    Gates, M.T.

    1993-01-01

    The Advanced Solar Cell Orbital Test (ASCOT) will test six types of solar cells in a high energy proton environment. During the design of the experiment a question was raised about the effects of proton radiation incident on the edge of the solar cells and whether edge radiation shielding was required. Historical geosynchronous data indicated that edge radiation damage is not detectable over the normal end of life solar cell degradation; however because the ASCOT radiation environment has a much higher and more energetic fluence of protons, considerably more edge damage is expected. A computer analysis of the problem was made by modeling the expected radiation damage at the cell edge and using a network model of small interconnected solar cells to predict degradation in the cell's electrical output. The model indicated that the deepest penetration of edge radiation was at the top of the cell near the junction where the protons have access to the cell through the low density cell/cover adhesive layer. The network model indicated that the cells could tolerate high fluences at their edge as long as there was high electrical resistance between the edge radiated region and the contact system on top of the cell. The predicted edge radiation related loss was less than 2% of maximum power for GaAs/Ge solar cells. As a result, no edge radiation protection was used for ASCOT

  6. Inhibition of K+ permeability diminishes alpha 2-adrenoceptor mediated effects on norepinephrine release

    International Nuclear Information System (INIS)

    Zimanyi, I.; Folly, G.; Vizi, E.S.

    1988-01-01

    The effect of two different potassium channel blockers, 4-aminopyridine (4-AP) and quinine, on the alpha 2-adrenoceptor mediated modulation of norepinephrine (NE) release was investigated. Pairs of mouse vasa deferentia were loaded with 3 H-norepinephrine ( 3 H-NE), superfused continuously, and stimulated electrically. 4-AP (5.3 x 10(-4) M), and quinine (10(-5) M) enhanced the stimulation-evoked release of tritium significantly. The electrically induced release of radioactivity was reduced by alpha 2-adrenoceptor agonists (1-NE and xylazine) and enhanced by the alpha 2-adrenoceptor antagonist yohimbine. Both effects were affected markedly by 4-AP or quinine: the depressant action of 1-NA and xylazine was partially antagonized and the facilitatory effect of yohimbine was completely abolished during the blockade of the potassium channels. It is suggested that the blockade of the potassium permeability counteracts negative feedback modulation; therefore, it seems likely that the stimulation of alpha 2-adrenoceptors leads to an enhanced potassium permeability and hyperpolarization of varicose axon terminals

  7. The effects of individual upper alpha neurofeedback in ADHD: an open-label pilot study.

    Science.gov (United States)

    Escolano, C; Navarro-Gil, M; Garcia-Campayo, J; Congedo, M; Minguez, J

    2014-12-01

    Standardized neurofeedback (NF) protocols have been extensively evaluated in attention-deficit/hyperactivity disorder (ADHD). However, such protocols do not account for the large EEG heterogeneity in ADHD. Thus, individualized approaches have been suggested to improve the clinical outcome. In this direction, an open-label pilot study was designed to evaluate a NF protocol of relative upper alpha power enhancement in fronto-central sites. Upper alpha band was individually determined using the alpha peak frequency as an anchor point. 20 ADHD children underwent 18 training sessions. Clinical and neurophysiological variables were measured pre- and post-training. EEG was recorded pre- and post-training, and pre- and post-training trials within each session, in both eyes closed resting state and eyes open task-related activity. A power EEG analysis assessed long-term and within-session effects, in the trained parameter and in all the sensors in the (1-30) Hz spectral range. Learning curves over sessions were assessed as well. Parents rated a clinical improvement in children regarding inattention and hyperactivity/impulsivity. Neurophysiological tests showed an improvement in working memory, concentration and impulsivity (decreased number of commission errors in a continuous performance test). Relative and absolute upper alpha power showed long-term enhancement in task-related activity, and a positive learning curve over sessions. The analysis of within-session effects showed a power decrease ("rebound" effect) in task-related activity, with no significant effects during training trials. We conclude that the enhancement of the individual upper alpha power is effective in improving several measures of clinical outcome and cognitive performance in ADHD. This is the first NF study evaluating such a protocol in ADHD. A controlled evaluation seems warranted due to the positive results obtained in the current study.

  8. The Effects of Ionizing Radiation on Mammalian Cells.

    Science.gov (United States)

    Biaglow, John E.

    1981-01-01

    Discusses the effects of radiation on dividing cells and factors influencing these effects; also briefly reviews the radical mechanism for radiation damage. Emphasizes the importance of oxygen in radiation effects. (CS)

  9. Secondary isotope effects on alpha-cleavage reactions

    International Nuclear Information System (INIS)

    Ingemann, S.; Hammerum, S.

    1980-01-01

    Kinetic deuterium isotope effects on mass spectral reactions have in several instances been utilized to provide structural information and to answer mechanistic questions. Typically, the influence of the deuterium label on the rate of one of a number of competing reactions has been studied. Secondary isotope effects have usually been assumed to be relatively insignificant in comparison with the observed kinetic effects, even though various workers have shown that secondary isotope effects may indeed exert a considerable influence on the rates of competing simple cleavages. Recent studies have provided quantitative data to show that the mere presence of deuterium atoms up to six bonds away may influence the rate of a simple cleavage reaction. In relation to an investigation of rearrangements accompanying simple cleavage reactions, a semi-quantitative measure was needed of the variation of the secondary isotope effect with the number of bonds between the deuterium label and the point of rupture. The influence has therefore been examined of the presence of remote deuterium atoms on a typical simple cleavage reaction, the α-cleavage of aliphatic amines. As a model compound, N-methyldipentylamine was chosen, systematically labelled with deuterium. (author)

  10. Chiral amphiphilic self-assembled alpha,alpha'-linked quinque-, sexi, and septithiophenes : synthesis, stability and odd-even effects

    NARCIS (Netherlands)

    Henze, O.; Feast, W.J.; Gardebien, F.; Jonkheijm, P.; Lazzaroni, R.; Leclère, P.E.L.G.; Meijer, E.W.; Schenning, A.P.H.J.

    2006-01-01

    The synthesis, characterization, and self-assembly in butanol of a series of well-defined ,'-linked quinqui-, sexi-, and septithiophenes substituted, via ester links at their termini, by chiral oligo(ethylene oxide) chains carrying an alpha, beta, delta, and epsilon methyl, respectively, are

  11. Significance of radiation-induced bystander effects in radiation therapy

    International Nuclear Information System (INIS)

    Suzuki, Masao

    2014-01-01

    Since 1994, a Phase I/II clinical study and radiotherapy have carried out using carbon-ion beams produced with the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences. Now we constructed the new treatment facility for the advanced carbon-ion therapy at HIMAC applying a 3D fast spot scanning system with pencil beams. In the field of fundamental biological studies for high-LET heavy ions, there are some reports regarding bystander effects after exposure to alpha particles derived from 238 Pu or He-ion microbeams. However, only limited sets of studies have examined bystander effects after exposure to different ion species heavier than helium, such as carbon ions. We have been investigating bystander cellular responses in both normal human and human tumor cells irradiated with the HIMAC carbon ions. Bystander cell-killing effect was observed in the cells harboring wild-type P53 gene, but not in the P53-mutated cells. Moreover, observed bystander effect was suppressed by treating with a specific inhibitor of gap-junction mediated cell-cell communication. There is clear evidence that the carbon-ion irradiation enables the enhanced cell killing in cells with wild-type P53 gene via gap-junction mediated bystander effect. (author)

  12. Internal friction, microstructure, and radiation effects

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Sommer, W.F.; Davidson, D.R.

    1984-01-01

    A brief review is given of internal friction relaxation peaks and background internal friction. The microstructural origin of the internal friction is discussed. Particular emphasis is placed on radiation effects

  13. Effects of solar radiation on glass

    Science.gov (United States)

    Tucker, Dennis S.; Kinser, Donald L.

    1991-01-01

    The effects of solar radiation of selected glasses are reported. Optical property degradation is studied using UV-Vis spectrophotometry. Strength changes are measured using a concentric ring bend test. Direct fracture toughness measurements using an indentation test are planned.

  14. Decomposition of radiational effects of model feedbacks

    International Nuclear Information System (INIS)

    Ellsaesser, H.W.; MacCracken, M.C.; Potter, G.L.; Mitchell, C.S.

    1981-08-01

    Three separate doubled CO 2 experiments with the statistical dynamic model are used to illustrate efforts to study the climate dynamics, feedbacks, and interrelationships of meteorological parameters by decomposing and isolating their individual effects on radiation transport

  15. Sterilizing radiation effects on selected polymers

    International Nuclear Information System (INIS)

    Skiens, W.E.

    1979-03-01

    The mechanism of radiation effects and their industrial applications are discussed for the following classes of polymers: thermoplastics, thermosets, elastomers, films and fibers, and adhesives/coatings/potting compounds. 35 references, 3 tables

  16. Radiobiology: Biologic effects of ionizing radiations

    International Nuclear Information System (INIS)

    Held, K.D.

    1987-01-01

    The biologic effects after exposure to ionizing radiation, such as cell death or tissue injury, result from a chain of complex physical, chemical, metabolic, and histologic events. The time scale of these radiation actions spans many orders of magnitude. The physical absorption of ionizing radiation occurs in about 10 -18 s, while late carcinogenic and genetic effects are expressed years or even generations later. Collectively, these effects form the science of radiobiology. Many of the concepts discussed in this chapter have been developed through the study of effects generated in tissues by external radiation sources, but they apply generally and often specifically to internally distributed radiopharmaceuticals which form the central topic of this book

  17. Genetic effects of ionizing radiations in Eucaryocytes

    International Nuclear Information System (INIS)

    Jullien, Pierre

    1976-01-01

    The litterature on the genetic effects of ionizing radiations is reviewed, especially as concerns specific loci or chromosome mutations. Extrapolation from one species to another is considered as well as extra-nuclear mutations [fr

  18. The effect of ionizing radiation on cyanophyta

    International Nuclear Information System (INIS)

    Kondrat'eva, N.V.; Shevchenko, T.F.; Golubkova, M.G.

    1989-01-01

    Publication data on the effect of ionizing radiation on cyanophyta are generalized. The conclusion about the presence of premises for forming cyanophyta radiobiology as special direction of procaryotic algae investigation is made

  19. [Effects of radiation exposure on human body].

    Science.gov (United States)

    Kamiya, Kenji; Sasatani, Megumi

    2012-03-01

    There are two types of radiation health effect; acute disorder and late on-set disorder. Acute disorder is a deterministic effect that the symptoms appear by exposure above a threshold. Tissues and cells that compose the human body have different radiation sensitivity respectively, and the symptoms appear in order, from highly radiosensitive tissues. The clinical symptoms of acute disorder begin with a decrease in lymphocytes, and then the symptoms appear such as alopecia, skin erythema, hematopoietic damage, gastrointestinal damage, central nervous system damage with increasing radiation dose. Regarding the late on-set disorder, a predominant health effect is the cancer among the symptoms of such as cancer, non-cancer disease and genetic effect. Cancer and genetic effect are recognized as stochastic effects without the threshold. When radiation dose is equal to or more than 100 mSv, it is observed that the cancer risk by radiation exposure increases linearly with an increase in dose. On the other hand, the risk of developing cancer through low-dose radiation exposure, less 100 mSv, has not yet been clarified scientifically. Although uncertainty still remains regarding low level risk estimation, ICRP propound LNT model and conduct radiation protection in accordance with LNT model in the low-dose and low-dose rate radiation from a position of radiation protection. Meanwhile, the mechanism of radiation damage has been gradually clarified. The initial event of radiation-induced diseases is thought to be the damage to genome such as radiation-induced DNA double-strand breaks. Recently, it is clarified that our cells could recognize genome damage and induce the diverse cell response to maintain genome integrity. This phenomenon is called DNA damage response which induces the cell cycle arrest, DNA repair, apoptosis, cell senescence and so on. These responses act in the direction to maintain genome integrity against genome damage, however, the death of large number of

  20. The effect of carbohydrates on alpha-amylase activity measurements

    NARCIS (Netherlands)

    Baks, T.; Janssen, A.E.M.; Boom, R.M.

    2006-01-01

    The Ceralpha method can be used for ¿-amylase activity measurements during the hydrolysis of starch at high substrate concentrations (>40 wt.%). However, the results are affected by the carbohydrates present in the samples. The effect of carbohydrates on the Ceralpha ¿-amylase activity

  1. Effects of radiations on ornamental fish

    International Nuclear Information System (INIS)

    Anita; Kalyankar, Amol D.; Ohlyan, Sunita; Gupta, R.K.

    2012-01-01

    Radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiations: ionizing and non-ionizing. Ultraviolet, X-rays, and gamma rays are some examples of radiation. 'Ornamental fish' is designed for aquatic hobbyists and the aquatic industry for several purposes. UV light has two primary uses in fish culture: Controlling green water and disinfecting the water supply. Many proponents of UV disinfection sometimes overlook the additional benefits relating to ornamental fish; those being that cleaner water reduces the stress on the fish by not having to fight off diseases, thus enhancing its immune system and leading to faster growth and more brilliant colors. Ultraviolet sterilizers are often used in aquaria to help control unwanted microorganisms in the water. UV radiation also ensures that exposed pathogens cannot reproduce, thus decreasing the likelihood of a disease outbreak in an aquarium. Despite of these benefits, the ill-effects of radiations cannot be ruled out. Ultraviolet Radiation-induced DNA Damage is seen in the skin of the Platyfish Xiphophorus. Higher radiation doses may cause the gastrointestinal syndrome that leads to defects of the intestinal mucosa barrier with successive contamination of musculature. Exposure to UV radiation can kill the fish and induce sublethal effects in embryos, larvae and adults. The change in skin includes irregularity of skin surface, epidermal oedema, necrosis etc. Irradiation may badly influence the textural attributes of fish muscle. (author)

  2. Effect of ionizing radiations on connective tissue

    International Nuclear Information System (INIS)

    Altman, K.I.; Gerber, G.B.

    1980-01-01

    The effects of ionizing radiations on connective tissue in lung, heart, vasculature, kidney, skin, and skeletal tissues are reviewed. Special emphasis is given to the effect of ionizing radiations on vasculo-connective tissue and fibrotic changes following radiation-induced injury to organs and tissues. In order to put the subject matter in proper prospective, the general biochemistry, physiology, and pathology of connective tissue is reviewed briefly together with the participation of connective tissue in disease. The review closes with an assessment of future problems and an enumeration and discussion of important, as yet unanswered questions

  3. Radiation abuse and its effects

    Energy Technology Data Exchange (ETDEWEB)

    Halm, A

    1976-06-01

    This paper delves into overuse practiced in diagnostic radiography. The conventional attitudes to low-dose irradiation are critically examined, as is the MPD related to individual radiosensitivity. Concern is expressed that a sizeable proportion of radiologists ignore important aspects of the Code of Practice and this attitude is readily emulated in the hospital setting. The author advocates education within the medical profession and the community on the risks involved in radiation abuse and the benefits derived from justified exposures to x rays.

  4. Radiation Effects in M and NEMS

    Science.gov (United States)

    2016-03-31

    electrical basis of operation of M&NEM structures? In particular, cumulative damage by non - ionizing energy loss can, in principle, alter the... Radiation Effects in M&NEMS Michael Alles, Kirill Bolotin, Alex Zettl, Brian Homeijer, Jim Davidson, Ronald Schrimpf, Robert Reed, Dan Fleetwood...understanding radiation effects on the relevant properties of the constituent materials and structures, particularly advanced 2D materials, and the

  5. Modifiers of radiation effects in the eye

    Science.gov (United States)

    Kleiman, Norman J.; Stewart, Fiona A.; Hall, Eric J.

    2017-11-01

    World events, including the threat of radiological terrorism and the fear of nuclear accidents, have highlighted an urgent need to develop medical countermeasures to prevent or reduce radiation injury. Similarly, plans for manned spaceflight to a near-Earth asteroid or journey to Mars raise serious concerns about long-term effects of space radiation on human health and the availability of suitable therapeutic interventions. At the same time, the need to protect normal tissue from the deleterious effects of radiotherapy has driven considerable research into the design of effective radioprotectors. For more than 70 years, animal models of radiation cataract have been utilized to test the short and long-term efficacy of various radiation countermeasures. While some compounds, most notably the Walter Reed (WR) class of radioprotectors, have reported limited effectiveness when given before exposure to low-LET radiation, the human toxicity of these molecules at effective doses limits their usefulness. Furthermore, while there has been considerable testing of eye responses to X- and gamma irradiation, there is limited information about using such models to limit the injurious effects of heavy ions and neutrons on eye tissue. A new class of radioprotector molecules, including the sulfhydryl compound PrC-210, are reported to be effective at much lower doses and with far less side effects. Their ability to modify ocular radiation damage has not yet been examined. The ability to non-invasively measure sensitive, radiation-induced ocular changes over long periods of time makes eye models an attractive option to test the radioprotective and radiation mitigating abilities of new novel compounds.

  6. Radiation effects on eye components

    International Nuclear Information System (INIS)

    Durchschlag, H.; Fochler, C.; Abraham, K.; Kulawik, B.

    1998-01-01

    The radiation damage (X-ray, UV light) of the most important components of the vertebrate eye (crystallins and other proteins, hyaluronic acid, vitreous, aqueous humour, ascorbic acid) has been investigated by various methods of physical chemistry. UV absorption and fluorescence spectroscopy as well as circular dichroism unveiled changes of the chromophores/fluorophores of the constituent biopolymers and low-molecular components, together with alterations of helix content and the occurrence of aggregation. Size-exclusion chromatography, analytical ultracentrifugation, densimetry, viscometry and light scattering experiments monitored changes of the global structure of proteins and polysaccharides involved. Electrophoreses allowed conclusions on fragmentation, unfolding and crosslinking. Analytical methods provided information regarding the integrity of groups of special concern (SH, SS) and revealed the existence of stable noxious species (H 2 O 2 ). By means of various measures and additives, manifold modifications of the impact of both ionizing and nonionizing radiation may be achieved. Caused by differences in the primary reactions, eye polymers are protected efficaciously by typical OH radical scavengers against X-irradiation, whereas compounds which exhibit absorption behavior in the UV range turn out to act as potent protectives ('chemical filters') against UV light. A few substances, such as ascorbate, are able to provide protection against both sorts of radiation and are even able to exhibit a slight chemical repair of already damaged particles. The results obtained are of importance for understanding pathological alterations of the eye (loss of transparency, cataractogenesis) and for developing new strategies for protection and repair of eye components. (author)

  7. Radiation effects on biodegradable polyesters

    International Nuclear Information System (INIS)

    Hiroshi Mitomo; Darmawan Darwis; Fumio Yoshii; Keizo Makuuchi

    1999-01-01

    Poly(3-hydroxybutyrate) [P(3HB)] and its copolymer poly(3-hydroxybutyrate-co-3hydroxyvalerate) [P(3HB-co-3HV)] are microbial biodegradable polyesters produced by many types of bacteria. Poly(butylene succinate) (PBS) and poly(E-caprolactone) (PCL) are also biodegradable synthetic polyesters which have been commercialized. These thermoplastics are expected for wide usage in environmental protection and blocompatible applications. Radiation grafting of hydrophilic monomers onto many polymers, e.g., polyethylene and polypropylene has been studied mainly for biomedical applications. In the present study, radiation-induced graft polymerization of vinyl monomers onto PHB and P(3HB-co-3HV) was carried out and improvement of their properties was studied. Changes in the properties and biodegradability were compared with the degree of grafting. Radiation-induced crosslinking of PBS and PCL which relatively show thermal and irradiation stability was also carried out to improve their thermal stability or processability. Irradiation to PBS and PCL mainly resulted in crosslinking and characterization of these crosslinked polyesters was investigated

  8. Perturbed effects at radiation physics

    International Nuclear Information System (INIS)

    Külahcı, Fatih; Şen, Zekâi

    2013-01-01

    Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer–Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables. - Highlights: • Perturbation methodology is applied to Radiation Physics. • Layer attenuation coefficient (LAC) and perturbed LAC are proposed for contact materials. • Perturbed linear attenuation coefficient is proposed. • Perturbed mass attenuation coefficient (PMAC) is proposed. • Perturbed cross-section is proposed

  9. Surface effect of KrF laser exposure on ECE of alpha particle tracks in polycarbonate polymer

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, P. [Physics Department, Amirkabir University, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of) and Laser Research Center, Atomic Energy Organization of Iran, AEOI, Tehran (Iran, Islamic Republic of)]. E-mail: parvin@aut.ac.ir; Jaleh, B. [Physics Department, Bu Ali Sina University, Hamadan (Iran, Islamic Republic of); Sheikh, N. [Gamma Irradiation Center, AEOI, Tehran (Iran, Islamic Republic of); Amiri, N. [Physics Department, Emam Hossien University, Tehran (Iran, Islamic Republic of)

    2005-11-15

    The optical penetration depth for polycarbonate (PC) at 308nm due to XeCl laser is about 450{mu}m while those of KrF (248nm) and ArF (193nm) lasers become noticeably shorter to 1{mu}m and 20nm, respectively, to show the strong superficial absorption at shorter UV wavelengths. On the other hand, KrF laser exposure on polycarbonate, at doses above 6J/cm{sup 2}, creates the surface crosslinking. In spite of several reliable methods available, such as 'hot set' and 'gel content', to determine the bulk crosslinking, there are a few consistent techniques to evaluate the surface crosslinking effect quantitatively. It includes hardening measurements using nanoindenter or AFM (atomic force microscopy). In this work, we present a technique for the measurement of superficial crosslinking, based on electrochemical etching of alpha irradiated polycarbonate accordingly. The mean diameter of the developed tracks nonlinearly decreases for KrF laser treatment at higher doses. The relative shrinkage of track diameters due to UV exposure before alpha irradiation, comparing to those without UV pre-radiation, indicates that UV laser makes the polymer surface hardened. The variation of mean track diameters can be strongly used to quantify the surface crosslinking.

  10. Surface effect of KrF laser exposure on ECE of alpha particle tracks in polycarbonate polymer

    International Nuclear Information System (INIS)

    Parvin, P.; Jaleh, B.; Sheikh, N.; Amiri, N.

    2005-01-01

    The optical penetration depth for polycarbonate (PC) at 308nm due to XeCl laser is about 450μm while those of KrF (248nm) and ArF (193nm) lasers become noticeably shorter to 1μm and 20nm, respectively, to show the strong superficial absorption at shorter UV wavelengths. On the other hand, KrF laser exposure on polycarbonate, at doses above 6J/cm 2 , creates the surface crosslinking. In spite of several reliable methods available, such as 'hot set' and 'gel content', to determine the bulk crosslinking, there are a few consistent techniques to evaluate the surface crosslinking effect quantitatively. It includes hardening measurements using nanoindenter or AFM (atomic force microscopy). In this work, we present a technique for the measurement of superficial crosslinking, based on electrochemical etching of alpha irradiated polycarbonate accordingly. The mean diameter of the developed tracks nonlinearly decreases for KrF laser treatment at higher doses. The relative shrinkage of track diameters due to UV exposure before alpha irradiation, comparing to those without UV pre-radiation, indicates that UV laser makes the polymer surface hardened. The variation of mean track diameters can be strongly used to quantify the surface crosslinking

  11. The alpha-particle irradiator set up at the ISS for radiobiological studies on targeted and non-targeted effects

    International Nuclear Information System (INIS)

    Esposito, G.; Antonelli, F.; Belli, M.; Campa, A.; Simone, G.; Sorrentino, E.; Tabocchini, M.A.

    2008-01-01

    In this paper we describe the alpha-particle irradiator that has been set up at the Istituto Superiore di Sanita (ISS) for controlled exposure of cultured mammalian cells. It can be equipped with two different sources, namely 2'4'4'Cm and 2'4'1'Am, allowing irradiation at different dose-rates (typically 1-100 mGy/min). The irradiator has dimensions small enough to be inserted into a standard cell culture incubator to perform irradiation of cultured cells in physiological conditions. The dose uniformity is such that the variations in the irradiation area are less than ± 12% of the average dose value on different irradiation areas up to ∼ 25 cm'2. Moreover, in the framework of the FP6 Euratom Integrated Project Non-targeted effects of ionizing radiation (NOTE), Petri dishes were realized for housing permeable membrane insert(s) to be used in co-culture experiments. Aluminium shields were also realized for half shield irradiation experiments. The alpha-particle irradiator of the ISS has been successfully used for studying DNA damage, namely double strand breaks (DSB, as measured by the γ-H2AX assay), in directly hit and in bystander primary human fibroblasts [it

  12. Effective dose: a radiation protection quantity

    CERN Document Server

    Menzel, H G

    2012-01-01

    Modern radiation protection is based on the principles of justification, limitation, and optimisation. Assessment of radiation risks for individuals or groups of individuals is, however, not a primary objective of radiological protection. The implementation of the principles of limitation and optimisation requires an appropriate quantification of radiation exposure. The International Commission on Radiological Protection (ICRP) has introduced effective dose as the principal radiological protection quantity to be used for setting and controlling dose limits for stochastic effects in the regulatory context, and for the practical implementation of the optimisation principle. Effective dose is the tissue weighted sum of radiation weighted organ and tissue doses of a reference person from exposure to external irradiations and internal emitters. The specific normalised values of tissue weighting factors are defined by ICRP for individual tissues, and used as an approximate age- and sex-averaged representation of th...

  13. Non-targeted effects of ionising radiation

    International Nuclear Information System (INIS)

    Belyakov, O.V.

    2008-01-01

    The universality of the target theory of radiation-induced effects is challenged by observations on non-targeted effects such as bystander effects and genomic instability. Essential features of non-targeted effects are that they do not require direct nuclear exposure by radiation and they are particularly significant at low doses. This new evidence suggests a need for a new paradigm in radiation biology. The new paradigm would cover both the classical (targeted) and the non-targeted effects. New aspects include the role of cellular communication and tissue-level responses. A better understanding of non-targeted effects may have important consequences for health risk assessment and, consequently, on radiation protection. Non-targeted effects may contribute to the estimation of cancer risk from occupational, medical and environmental exposures. In particular, they may have implications for the applicability of the Linear-No-Threshold (LNT) model in extrapolating radiation risk data into the low-dose region. This also means that the adequacy of the concept of dose to estimate risk is challenged by these findings. Moreover, these effects may provide new mechanistic explanations for the development of non-cancer diseases. Further research is required to determine if these effects, typically measured in cell cultures, are applicable in tissue level, whole animals, and ultimately in humans. (orig.)

  14. Biological effects of high-energy radiation

    International Nuclear Information System (INIS)

    Curtis, S.B.

    1976-01-01

    The biological effects of high-energy radiation are reviewed, with emphasis on the effects of the hadronic component. Proton and helium ion effects are similar to those of the more conventional and sparsely ionizing x- and γ-radiation. Heavy-ions are known to be more biologically effective, but the long term hazard from accumulated damage has yet to be assessed. Some evidence of widely varying but dramatically increased effectiveness of very high-energy (approximately 70 GeV) hadron beams is reviewed. Finally, the importance of the neutron component in many situations around high-energy accelerators is pointed out

  15. Biological effects and hazards of radiation exposure

    International Nuclear Information System (INIS)

    Boas, J.F.; Solomon, S.B.

    1990-01-01

    Radiation induced carcinogenesis and mutagenesis form the main risk to health from exposure to low levels of radiation. This risk effects can be at least qualitatively understood by considering the effects of radiation on cell DNA. Whilst exposure to high levels of radiation results in a number of identifiable effects, exposure to low levels of radiation may result in effects which only manifest themselves after many years. Risk estimates for low levels of radiation have been derived on the basis of a number of assumptions. In the case of uranium mine workers a major hazard arises from the inhalation of radon daughters. Whilst the correlation between radon daughter exposure and lung cancer incidence is well established, the numerical value of the risk factor is the subject of controversy. ICRP 50 gives a value of 10 cases per 10 6 person-years at risk per WLM (range 5-15 x 10 -6 PYR -1 WLM -1 ). The effect of smoking on lung cancer incidence rates amongst miners is also controversial. Nevertheless, smoking by miners should be discouraged

  16. The effect of spectral filters on VEP and alpha-wave responses

    Directory of Open Access Journals (Sweden)

    Kevin T. Willeford

    2016-04-01

    Conclusions: The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75% to luminance, and in some cases, specific spectral effects (e.g., blue and red. VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared.

  17. Effect of hydrostatic pressure on the tensile properties of alpha uranium

    International Nuclear Information System (INIS)

    Chandler, E.F.

    1984-09-01

    This report examines the effect of a superimposed hydrostatic pressure on the tensile properties of four grades of rolled unalloyed alpha uranium. The materials varied in carbon content and heat treatment. The principal effect of increasing pressure is an increase in the ductility of the materials. By not heat treating the uranium after the rolling process, the interaction of carbon content on mechanical properties is almost nullified. (author)

  18. Radiation abuse and its effects

    International Nuclear Information System (INIS)

    Halm, A.

    1976-01-01

    This paper delves into overuse practiced in diagnostic radiography. The conventional attitudes to low-dose irradiation are critically examined, as is the MPD related to individual radiosensitivity. Concern is expressed that a sizeable proportion of radiologists ignore important aspects of the Code of Practice and this attitude is readily emulated in the hospital setting. The author advocates education within the medical profession and the community on the risks involved in radiation abuse and the benefits derived from justified exposures to x rays. (author)

  19. The effects of ionizing radiation and review of the Young-Woollard document

    International Nuclear Information System (INIS)

    Marko, A.M.; Myers, D.K.

    1983-04-01

    A review of a document entitled 'The Health Dangers of Uranium Mining and Jurisdictional Questions' has been prepared. E.R. Young and R.F. Woollard submitted, in 1980, this document to the British Columbia Royal Commission of Inquiry, Health and Environmental Protection - Uranium Mining (INIS-mf--7757). When we reviewed the document it became clear that the views concerning effects of low-level radiation including alpha irradiation do not have scientific consensus. For this reason we have included a brief summary of conclusions produced by various international and national bodies on the effects of radiation on humans

  20. Experimental setup for studying the effects of alpha particles on zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Yum, E.H.W.; Ng, C.K.M. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Lin, A.C.C.; Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong (China)], E-mail: peter.yu@cityu.edu.hk

    2007-11-15

    In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 {mu}m were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human.

  1. Experimental setup for studying the effects of alpha particles on zebrafish embryos

    International Nuclear Information System (INIS)

    Yum, E.H.W.; Ng, C.K.M.; Lin, A.C.C.; Cheng, S.H.; Yu, K.N.

    2007-01-01

    In the present work, we have studied the feasibility to use an experimental setup based on polyallyldiglycol-carbonate (PADC) films to study effects of alpha particles on dechorionated zebrafish embryos. Thin PADC films with a thickness of 16 μm were prepared from commercially available CR-39 films by chemical etching and used as support substrates for holding zebrafish embryos for alpha-particle irradiation. These films recorded alpha-particle hit positions, quantified the number and energy of alpha particles actually incident on the embryo cells, and thus enabled the calculation of the dose absorbed by the embryo cells. Irradiation was made at 4 h post fertilization (hpf) with absorbed doses up to 2.3 mGy. Images of the embryos at 48 hpf were examined for identification of morphologic abnormalities. The preliminary results showed that absorbed doses corresponding to the abnormally developed embryos ranged from 0.41 to 2.3 mGy, which was equivalent to 0.21-1.2 mGy in human

  2. Effect of alpha 2-adrenoceptor agonists on gastric pepsin and acid secretion in the rat.

    Science.gov (United States)

    Tazi-Saad, K.; Chariot, J.; Del Tacca, M.; Rozé, C.

    1992-01-01

    1. The purpose of the present study was to analyze the effects of the alpha 2-adrenoceptor agonists clonidine, guanabenz, detomidine and medetomidine on pepsin secretion in conscious rats provided with gastric chronic fistula and to compare this with acid secretion. 2. Basal interdigestive gastric secretion, which is mainly neurally driven in the rat, and the secretion directly stimulated by the two main stimulants of chief cells, cholecystokinin octapeptide (CCK8) and methacholine, were studied. 3. Basal secretion of pepsin and acid was inhibited by all four drugs with comparable EC50S. 4. CCK-stimulated pepsin and acid secretion was less sensitive than basal pepsin and acid secretion to alpha 2-adrenoceptor inhibition. 5. Methacholine-stimulated pepsin and acid secretion was not changed by clonidine and guanabenz; methacholine-stimulated acid was even marginally increased by clonidine. 6. These results do not favour the presence of alpha 2-receptors on chief cells in the rat stomach. They rather suggest that pepsin inhibition by alpha 2-adrenoceptor agonists is indirect and due to central or peripheral inhibition of the discharge of nerve fibres activating pepsin secretion. PMID:1356566

  3. Biological Effects of Ionizing Radiation

    International Nuclear Information System (INIS)

    Durand, J.L.

    2000-01-01

    The aim of this work is to verify the existence of the adaptive response phenomenon induced by low doses of ionizing radiation in living cells.A wild-type yeast Saccharomyces cerevisiae (Baker's yeast) was chosen as the biological target.As a parameter to quantify the sensibility of the target to radiation, the Lethal Dose 50 (LD50 ) was observed. In our experimental condition a value of (60 ± 1) Gy was measured for LD50 with Dose Rate of (0.44 ± 0.03) Gy/min. The method employed to show up the adaptive response phenomenon consisted in exposing the sample to low ''conditioning'' doses, which would initiate these mechanisms. Later the samples with and without conditioning were exposed to higher ''challenging'' doses (such as LD50), and the surviving fractions were compared. In order to maximize the differences, the doses and the time between irradiations were varied. The best results were obtained with both a conditioning dose of (0.44 ± 0.03) Gy and a waiting time of 2 hs until the application of the challenging dose. Following this procedures the 80% of the conditioned samples has survived, after receiving the application of the LD50. The adaptive response phenomenon was also verified for a wide range of challenging doses

  4. Bi209 alpha activity

    International Nuclear Information System (INIS)

    Araujo Penna, M.M. de.

    1970-01-01

    The study for measuring Bi 209 alpha activity is presented. Ilford L4 nuclear emulsion pellicles loaded with bismuth citrate to obtain a load of 100 mg/cm 3 of dry emulsion, were prepared. Other pellicles were prepared with the same. Ilford L4 gel to estimate the background radiation. To observe 'fading' effect, pellicles loaded with bismuth were submitted to neutrons of high energy, aiming to record recoil proton tracks. The pellicles were confined in nitrogen atmosphere at temperature lower than -10 0 C. The Bi 209 experimental half-life was obtained and compared with the estimated theoretical data. (M.C.K.) [pt

  5. Individual Alpha Peak Frequency Predicts 10 Hz Flicker Effects on Selective Attention.

    Science.gov (United States)

    Gulbinaite, Rasa; van Viegen, Tara; Wieling, Martijn; Cohen, Michael X; VanRullen, Rufin

    2017-10-18

    Rhythmic visual stimulation ("flicker") is primarily used to "tag" processing of low-level visual and high-level cognitive phenomena. However, preliminary evidence suggests that flicker may also entrain endogenous brain oscillations, thereby modulating cognitive processes supported by those brain rhythms. Here we tested the interaction between 10 Hz flicker and endogenous alpha-band (∼10 Hz) oscillations during a selective visuospatial attention task. We recorded EEG from human participants (both genders) while they performed a modified Eriksen flanker task in which distractors and targets flickered within (10 Hz) or outside (7.5 or 15 Hz) the alpha band. By using a combination of EEG source separation, time-frequency, and single-trial linear mixed-effects modeling, we demonstrate that 10 Hz flicker interfered with stimulus processing more on incongruent than congruent trials (high vs low selective attention demands). Crucially, the effect of 10 Hz flicker on task performance was predicted by the distance between 10 Hz and individual alpha peak frequency (estimated during the task). Finally, the flicker effect on task performance was more strongly predicted by EEG flicker responses during stimulus processing than during preparation for the upcoming stimulus, suggesting that 10 Hz flicker interfered more with reactive than proactive selective attention. These findings are consistent with our hypothesis that visual flicker entrained endogenous alpha-band networks, which in turn impaired task performance. Our findings also provide novel evidence for frequency-dependent exogenous modulation of cognition that is determined by the correspondence between the exogenous flicker frequency and the endogenous brain rhythms. SIGNIFICANCE STATEMENT Here we provide novel evidence that the interaction between exogenous rhythmic visual stimulation and endogenous brain rhythms can have frequency-specific behavioral effects. We show that alpha-band (10 Hz) flicker impairs stimulus

  6. Ovarian response markers lead to appropriate and effective use of corifollitropin alpha in assisted reproduction.

    Science.gov (United States)

    La Marca, Antonio; D'Ippolito, Giovanni

    2014-02-01

    Corifollitropin alpha is a highly effective gonadotrophin, which maintains multifollicular growth for a week. The advantages of its administration include ease of use of the drug, making the treatment more patient friendly, resulting in a lower level of distress for the patient. At the same time, the pregnancy rate resulting from its use in IVF/intracytoplasmic sperm injection cycles is similar to that found when daily recombinant FSH is administered. The ovarian response to corifollitropin alpha is dependent on clinically established predictors such as baseline FSH, antral follicle count (AFC) and age. There is a general trend towards a higher ovarian response with an increasing AFC and the number of oocytes per attempt decreased with increasing baseline FSH and age. Even if the risk of ovarian hyperstimulation syndrome following corifollitropin alpha is very similar to the rate reported in literature for young women undergoing IVF, the risk of overstimulation may be reduced by avoiding maximal ovarian stimulation in women anticipated to be hyperresponders. High basal anti-Müllerian hormone and/or AFC can identify women with enhanced functional ovarian reserve at risk of overstimulation, and the risk is even higher if maximally stimulated with corifollitropin alpha or high dose of daily recombinant FSH. Corifollitropin alpha is a highly effective gonadotrophin which maintains multifollicular growth for a week. The ovarian response to corifollitropin was demonstrated to be dependent on clinically established predictors such as baseline FSH, antral follicle count (AFC) and age. There was a general trend toward a higher ovarian response with an increasing AFC and the mean number of oocytes per attempt decreased with increasing baseline FSH and age. Even if the risk of ovarian hyperstimulation syndrome (OHSS) following corifollitropin alpha is very similar to the rate of OHSS reported in literature for young women undergoing IVF, the risk of overstimulation may be

  7. Energy landscape, structure and rate effects on strength properties of alpha-helical proteins

    International Nuclear Information System (INIS)

    Bertaud, Jeremie; Hester, Joshua; Jimenez, Daniel D; Buehler, Markus J

    2010-01-01

    The strength of protein domains is crucial to identify the mechanical role of protein domains in biological processes such as mechanotransduction, tissue mechanics and tissue remodeling. Whereas the concept of strength has been widely investigated for engineered materials, the strength of fundamental protein material building blocks and how it depends on structural parameters such as the chemical bonding, the protein filament length and the timescale of observation or deformation velocity remains poorly understood. Here we report a systematic analysis of the influence of key parameters that define the energy landscape of the strength properties of alpha-helical protein domains, including energy barriers, unfolding and refolding distances, the locations of folded and unfolded states, as well as variations of the length and pulling velocity of alpha-helical protein filaments. The analysis is facilitated by the development of a double-well mesoscale potential formulation, utilized here to carry out a systematic numerical analysis of the behavior of alpha-helices. We compare the results against widely used protein strength models based on the Bell model, one of the simplest models used to characterize the strength of protein filaments. We find that, whereas Bell-type models are a reasonable approximation to describe the rupture of alpha-helical protein domains for a certain range of pulling speeds and values of energy barriers, the model ceases to hold for very large energy barriers and for very small pulling speeds, in agreement with earlier findings. We conclude with an application of our mesoscale model to investigate the effect of the length of alpha-helices on their mechanical strength. We find a weakening effect as the length of alpha-helical proteins increases, followed by an asymptotic regime in which the strength remains constant. We compare strand lengths found in biological proteins with the scaling law of strength versus alpha-helix filament length. The

  8. Radiation effects on ion exchange materials

    International Nuclear Information System (INIS)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references

  9. Radiation effects on ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references.

  10. Radiation effects on optical data transmission systems

    International Nuclear Information System (INIS)

    Leskovar, B.

    1989-01-01

    The state of the art of optical transmitters, low loss fiber waveguides and receivers in both steady state and pulsed radiation environments is reviewed and summarized. Emphasis is placed on the effects of irradiation on the performance of light emitting and laser diodes, optical fiber waveguides and photodiodes. The influence of radiation-induced attenuation of optical fibers due to total dose, dose rate, time after irradiation, temperature, radiation history, photobleaching, OH and impurity content, dopant type and concentration is described. The performance of candidate components of the transmission system intended for deployment in the Superconducting Super Collider Detector and primary beam tunnel nuclear environment is discussed

  11. Exploring graphene field effect transistor devices to improve spectral resolution of semiconductor radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Richard Karl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Jeffrey B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hamilton, Allister B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-12-01

    Graphene, a planar, atomically thin form of carbon, has unique electrical and material properties that could enable new high performance semiconductor devices. Graphene could be of specific interest in the development of room-temperature, high-resolution semiconductor radiation spectrometers. Incorporating graphene into a field-effect transistor architecture could provide an extremely high sensitivity readout mechanism for sensing charge carriers in a semiconductor detector, thus enabling the fabrication of a sensitive radiation sensor. In addition, the field effect transistor architecture allows us to sense only a single charge carrier type, such as electrons. This is an advantage for room-temperature semiconductor radiation detectors, which often suffer from significant hole trapping. Here we report on initial efforts towards device fabrication and proof-of-concept testing. This work investigates the use of graphene transferred onto silicon and silicon carbide, and the response of these fabricated graphene field effect transistor devices to stimuli such as light and alpha radiation.

  12. Radiation effects on the integrity of paper

    International Nuclear Information System (INIS)

    Otero D'Almeida, Maria Luiza; Medeiros Barbosa, Patricia de Souza; Boaratti, Marcelo Fernando Guerra; Borrely, Sueli Ivone

    2009-01-01

    Books and documents attacked by fungi and insects have already been treated by radiation for disinfestations purposes. However, there is still need to investigate the influence of radiation on the cellulose paper structure. The aim of this research was to study the effects of radiation on paper properties, especially those related to strength and appearance. Paper sheets for this study were prepared in the laboratory, using bleached eucalyptus pulp as raw material. No additives were used to concentrate the attention only on the effects of irradiation on the pure cellulose matrix. The samples were irradiated at IPEN's 60 Co Gammacell irradiator with six radiation doses, from 3 to 15 kGy at the dose rate 0.817 Gy/s. The properties of paper sheets were tested after irradiation and compared with unirradiated samples according to ISO methods. No significant changes were detected in paper samples irradiated up to 15 kGy.

  13. Effect of gamma radiation on Campylobacter jejuni

    International Nuclear Information System (INIS)

    Lambert, J.D.; Maxcy, R.B.

    1984-01-01

    Radiation resistance of Campylobacter jejuni in broth, ground beef, and ground turkey meat was determined using dose levels from 0-200 Krad at -30 +/- 10 0 C, at 0-5 0 C, and at 30 +/- 10 0 C. Irradiation at -30 0 C increased radiation resistance of cultures in ground meats; broth cultures were not greatly influenced by temperature. The effect of culture age on radiation resistance was also evaluated using cells in various physiological phases. Age did not have a pronounced effect on radiation resistance. The largest D 10 value for C. jejuni was 32 Krad, which was less than D 10 values commonly reported for salmonellae. 20 references, 4 figures

  14. Radiation effects on DNA methylation in mice

    International Nuclear Information System (INIS)

    Komura, J.; Kurishita, A.; Miyamura, Y.; Ono, T.; Tawa, R.; Sakurai, H.

    1992-01-01

    Effects of ionizing radiation on DNA methylation in liver, brain and spleen were examined by high performance liquid chromatography (HPLC). The total methylated cytosine level in the genome was reduced within 8 hours after 3.8 Gy of irradiation in liver of adult mice. But no appreciable effect was observed in brain and spleen. When mice were irradiated at newborn, liver DNA revealed no change in methylated cytosine level. Even though slight effects of radiation were detected in he methylation of the c-myc and c-fos genes, they were only temporary and no long-term effects were observed. These data suggest that the effect of radiation on DNA methylation in vivo is not prevailing a DNA damage, but rather influenced much through biological parameters. (author)

  15. {sup 213}Bi-DOTATOC receptor-targeted alpha-radionuclide therapy induces remission in neuroendocrine tumours refractory to beta radiation: a first-in-human experience

    Energy Technology Data Exchange (ETDEWEB)

    Kratochwil, C.; Giesel, F.L.; Mier, W.; Haberkorn, U. [University Hospital Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); Bruchertseifer, F.; Apostolidis, C.; Morgenstern, A. [European Commission, Institute for Transuranium Elements, Karlsruhe (Germany); Boll, R.; Murphy, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2014-11-15

    Radiopeptide therapy using a somatostatin analogue labelled with a beta emitter such as {sup 90}Y/{sup 177}Lu-DOTATOC is a new therapeutic option in neuroendocrine cancer. Alternative treatments for patients with refractory disease are rare. Here we report the first-in-human experience with {sup 213}Bi-DOTATOC targeted alpha therapy (TAT) in patients pretreated with beta emitters. Seven patients with progressive advanced neuroendocrine liver metastases refractory to treatment with {sup 90}Y/{sup 177}Lu-DOTATOC were treated with an intraarterial infusion of {sup 213}Bi-DOTATOC, and one patient with bone marrow carcinosis was treated with a systemic infusion of {sup 213}Bi-DOTATOC. Haematological, kidney and endocrine toxicities were assessed according to CTCAE criteria. Radiological response was assessed with contrast-enhanced MRI and {sup 68}Ga-DOTATOC-PET/CT. More than 2 years of follow-up were available in seven patients. The biodistribution of {sup 213}Bi-DOTATOC was evaluable with 440 keV gamma emission scans, and demonstrated specific tumour binding. Enduring responses were observed in all treated patients. Chronic kidney toxicity was moderate. Acute haematotoxicity was even less pronounced than with the preceding beta therapies. TAT can induce remission of tumours refractory to beta radiation with favourable acute and mid-term toxicity at therapeutic effective doses. (orig.)

  16. 213Bi-DOTATOC receptor-targeted alpha-radionuclide therapy induces remission in neuroendocrine tumours refractory to beta radiation: a first-in-human experience

    International Nuclear Information System (INIS)

    Kratochwil, C.; Giesel, F.L.; Mier, W.; Haberkorn, U.; Bruchertseifer, F.; Apostolidis, C.; Morgenstern, A.; Boll, R.; Murphy, K.

    2014-01-01

    Radiopeptide therapy using a somatostatin analogue labelled with a beta emitter such as 90 Y/ 177 Lu-DOTATOC is a new therapeutic option in neuroendocrine cancer. Alternative treatments for patients with refractory disease are rare. Here we report the first-in-human experience with 213 Bi-DOTATOC targeted alpha therapy (TAT) in patients pretreated with beta emitters. Seven patients with progressive advanced neuroendocrine liver metastases refractory to treatment with 90 Y/ 177 Lu-DOTATOC were treated with an intraarterial infusion of 213 Bi-DOTATOC, and one patient with bone marrow carcinosis was treated with a systemic infusion of 213 Bi-DOTATOC. Haematological, kidney and endocrine toxicities were assessed according to CTCAE criteria. Radiological response was assessed with contrast-enhanced MRI and 68 Ga-DOTATOC-PET/CT. More than 2 years of follow-up were available in seven patients. The biodistribution of 213 Bi-DOTATOC was evaluable with 440 keV gamma emission scans, and demonstrated specific tumour binding. Enduring responses were observed in all treated patients. Chronic kidney toxicity was moderate. Acute haematotoxicity was even less pronounced than with the preceding beta therapies. TAT can induce remission of tumours refractory to beta radiation with favourable acute and mid-term toxicity at therapeutic effective doses. (orig.)

  17. Modification of certain pharmacological effects of ethanol by lipophilic alpha-1 adrenergic agonists

    Energy Technology Data Exchange (ETDEWEB)

    Menon, M.K.; Dinovo, E.C.; Haddox, V.G.

    1987-09-28

    The influence of four centrally-acting alpha-1 adrenoceptor agonists, namely, 2(2-chloro-5-trifluoromethylphenylimino) imidazolidine (St 587), cirazoline, (-) 1,2,3,4-tetrahydro-8-methoxy-5-methylthio-2-naphthalenamine ((-)SKF 89748A) and 2-(2-methylindazol-4-imino)imidazolidine (Sgd 101/75) on the pharmacological effects of ethanol was investigated. All four drugs reduced the duration of ethanol-induced hypnosis in C57B1/6 mice, this effect being proportional to their relative potencies to exert central alpha-1 agonism. In prazosin-pretreated mice, St 587 failed to reduce the hypnotic effect of ethanol, which provided strong evidence for the role of alpha-1 agonism for the hypnosis reducing effect of St 587. Hyperactivity induced in C57B1/6 mice by a subhypnotic dose of ethanol and St 587 was reported earlier. In the present study, St 587, cirazoline and (-)SKF 89748A produced similar response, but no correlation between this effect and ethanol hypnosis blockade could be established. 19 references, 8 figures, 2 tables.

  18. Evidence for beneficial low level radiation effects and radiation hormesis

    International Nuclear Information System (INIS)

    Feinendegen, L.E.

    2005-01-01

    Low doses in the mGy range cause a dual effect on cellular DNA. One effect concerns a relatively low probability of DNA damage per energy deposition event and it increases proportional with dose, with possible bystander effects operating. This damage at background radiation exposure is orders of magnitudes lower than that from endogenous sources, such as ROS. The other effect at comparable doses brings an easily obeservable adaptive protection against DNA damage from any, mainly endogenous sources, depending on cell type, species, and metabolism. Protective responses express adaptive responses to metabolic perturbations and also mimic oxygen stress responses. Adaptive protection operates in terms of DNA damage prevention and repair, and of immune stimulation. It develops with a delay of hours, may last for days to months, and increasingly disappears at doses beyond about 100 to 200 mGy. Radiation-induced apoptosis and terminal cell differentiation occurs also at higher doses and adds to protection by reducing genomic instability and the number of mutated cells in tissues. At low doses, damage reduction by adaptive protection against damage from endogenous sources predictably outweighs radiogenic damage induction. The analysis of the consequences of the particular low-dose scenario shows that the linear-no-threshold (LNT) hypothesis for cancer risk is scientifically unfounded and appears to be invalid in favor of a threshold or hormesis. This is consistent with data both from animal studies and human epidemiological observations on low-dose induced cancer. The LNT hypothesis should be abandoned and be replaced by a hypothesis that is scientifically justified. The appropriate model should include terms for both linear and non-linear response probabilities. Maintaining the LNT-hypothesis as basis for radiation protection causes unressonable fear and expenses. (author)

  19. The radiation effects on the living cell

    International Nuclear Information System (INIS)

    Sage, E.; Dutrillaux, B.; Soussi, Th.; Boiteux, S.; Lopez, B.; Feunteun, J.

    1999-06-01

    This publication is a presentation of particular points discussed during the colloquium of the 15-18 june 1999, for which scientific researches are performed at the CEA/CNRS. They deal with the radiobiology, for the radiation effects on living matter; with the DNA, for the knowledge and repair mechanisms on cells submitted to ionizing radiations; with the exposition to UV in correlation with neoplasms; with the P53 gene which is a tumour suppressor. (A.L.B.)

  20. Genetic effects of radiation. Annex I

    International Nuclear Information System (INIS)

    1982-01-01

    This Annex is aimed at an updating of the 1977 UNSCEAR report, which presented a detailed review of the genetic effects of ionizing radiation, especially those parts that require significant revisions in the light of new data. There is an extensive bibliography with over 1000 references. Particular emphasis is given to those data that are relevant to the evaluation of genetic radiation hazards in man.