Science.gov

Sample records for dose gamma-radiation induced

  1. Gamma Radiation Doses In Sweden

    SciTech Connect

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-08-07

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

  2. Low-Dose Gamma Radiation Does Not Induce an Adaptive Response for Micronucleus Induction in Mouse Splenocytes.

    PubMed

    Bannister, L A; Serran, M L; Mantha, R R

    2015-11-01

    Low-dose ionizing radiation is known to induce radioadaptive responses in cells in vitro as well as in mice in vivo. Low-dose radiation decreases the incidence and increases latency for spontaneous and radiation-induced tumors in mice, potentially as a result of enhanced cellular DNA repair efficiency or a reduction in genomic instability. In this study, the cytokinesis-block micronucleus (CBMN) assay was used to examine dose response and potential radioadaptive response for cytogenetic damage and cell survival in C57BL/6 and BALB/c spleen cells exposed in vitro or in vivo to low-dose 60Co gamma radiation. The effects of genetic background, radiation dose and dose rate, sampling time and cell cycle were investigated with respect to dose response and radioadaptive response. In C57BL/6 mice, a linear-quadratic dose-response relationship for the induction of micronuclei (MN) was observed for doses between 100 mGy and 2 Gy. BALB/c mice exhibited increased radiosensitivity for MN induction compared to C57BL/6 mice. A 20 mGy dose had no effect on MN frequencies in splenocytes of either mouse strain, however, increased spleen weight and a reduced number of dead cells were noted in the C57BL/6 strain only. Multiple experimental parameters were investigated in radioadaptive response studies, including dose and dose rate of the priming dose (20 mGy at 0.5 mGy/min and 100 mGy at 10 mGy/min), time interval (4 and 24 h) between priming and challenge doses, cell cycle stage (resting or proliferating) at exposure and kinetics after the challenge dose. Radioadaptive responses were not observed for MN induction for either mouse strain under any of the experimental conditions investigated. In contrast, a synergistic response for radiation-induced micronuclei in C57BL/6 spleen was detected after in vivo 20 mGy irradiation. This increase in the percentage of cells with cytogenetic damage was associated with a reduction in the number of nonviable spleen cells, suggesting that low-dose

  3. High doses of gamma radiation suppress allergic effect induced by food lectin

    NASA Astrophysics Data System (ADS)

    Vaz, Antônio F. M.; Souza, Marthyna P.; Vieira, Leucio D.; Aguiar, Jaciana S.; Silva, Teresinha G.; Medeiros, Paloma L.; Melo, Ana M. M. A.; Silva-Lucca, Rosemeire A.; Santana, Lucimeire A.; Oliva, Maria L. V.; Perez, Katia R.; Cuccovia, Iolanda M.; Coelho, Luana C. B. B.; Correia, Maria T. S.

    2013-04-01

    One of the most promising areas for the development of functional foods lies in the development of effective methods to reduce or eliminate food allergenicity, but few reports have summarized information concerning the progress made with food irradiation. In this study, we investigated the relationship between allergenicity and molecular structure of a food allergen after gamma irradiation and evaluate the profile of the allergic response to irradiated allergens. Cramoll, a lectin isolated from a bean and used as a food allergen, was irradiated and the possible structural changes were accompanied by spectrofluorimetry, circular dichroism and microcalorimetry. Subsequently, sensitized animals subjected to intragastric administration of non-irradiated and irradiated Cramoll were treated for 7 days. Then, body weight, leukocytes, cytokine profiles and histological parameters were also determined. Cramoll showed complete inhibition of intrinsic activity after high radiation doses. Changes in fluorescence and CD spectra with a simultaneous collapse of the tertiary structure followed by a pronounced decrease of native secondary structure were observed after irradiation. After oral challenge, sensitized mice demonstrate an association between Cramoll intake, body weight loss, eosinophilia, lymphocytic infiltrate in the gut and Eotaxin secretion. Irradiation significantly reduces, according to the dose, the effects observed by non-irradiated food allergens. We confirm that high-dose radiation may render protein food allergens innocuous by irreversibly compromising their molecular structure.

  4. Modification of microcrystalline cellulose by gamma radiation-induced grafting

    NASA Astrophysics Data System (ADS)

    Madrid, Jordan F.; Abad, Lucille V.

    2015-10-01

    Modified microcrystalline cellulose (MCC) was prepared through gamma radiation-induced graft polymerization of glycidyl methacrylate (GMA). Simultaneous grafting was employed wherein MCC with GMA in methanol was irradiated with gamma radiation in nitrogen atmosphere. The effects of different experimental factors such as monomer concentration, type of solvent and absorbed dose on the degree of grafting, Dg, were studied. The amount of grafted GMA, expressed as Dg, was determined gravimetrically. Information from grafted samples subjected to Fourier transformed infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode showed peaks corresponding to GMA which indicates successful grafting. The X-ray diffraction (XRD) analysis revealed that the crystalline region of MCC was not adversely affected after grafting with GMA. The thermogravimetric analysis (TGA) data showed that the decomposition of grafted MCC occurred at higher temperature compared to the base MCC polymer.

  5. Caffeine induces a second wave of apoptosis after low dose-rate gamma radiation of HL-60 cells.

    PubMed

    Vávrová, Jirina; Mareková-Rezácová, Martina; Vokurková, Doris; Szkanderová, Sylva; Psutka, Jan

    2003-10-01

    Most cell lines that lack functional p53 protein are arrested in the G(2) phase of the cell cycle due to DNA damage. It was previously found that the human promyelocyte leukemia cells HL-60 (TP53 negative) that had been exposed to ionizing radiation at doses up to 10 Gy were arrested in the G(2) phase for a period of 24 h. The radioresistance of HL-60 cells that were exposed to low dose-rate gamma irradiation of 3.9 mGy/min, which resulted in a pronounced accumulation of the cells in the G(2) phase during the exposure period, increased compared with the radioresistance of cells that were exposed to a high dose-rate gamma irradiation of 0.6 Gy/min. The D(0) value (i.e. the radiation dose leading to 37% cell survival) for low dose-rate radiation was 3.7 Gy and for high dose-rate radiation 2.2 Gy. In this study, prevention of G(2) phase arrest by caffeine (2 mM) and irradiation of cells with low dose-rate irradiation in all phases of the cell cycle proved to cause radiosensitization (D(0)=2.2 Gy). The irradiation in the presence of caffeine resulted in a second wave of apoptosis on days 5-7 post-irradiation. Caffeine-induced apoptosis occurring later than day 7 post-irradiation is postulated to be a result of unscheduled DNA replication and cell cycle progress.

  6. Gamma-radiation-induced phosphorylation of p53 on serine 15 is dose-dependent in MOLT-4 leukaemia cells.

    PubMed

    Tichý, A; Záskodová, D; Zoelzer, F; Vávrová, J; Sinkorová, Z; Pejchal, J; Osterreicher, J; Rezácová, M

    2009-01-01

    Molecular indicators of the absorbed dose of ionizing radiation are powerful tools in biodosimetry. The studies reported here were undertaken with the motivation to find such a marker among the mo lecules involved in ataxia-telangiectasia mutated kinase- dependent signalling induced by ionizing radiation (ATM-kinase, checkpoint kinase-2, protein p53, and oncoprotein Mdm2). In our previous work on T-lymphocyte leukaemia MOLT-4 cells we described the mentioned molecules of ATM-dependent pathway and none of them showed a pronounced dosedependent response. Here we employed Western blotting and ELISA assay to investigate the response of post-translationally modified p53 (particularly phosphorylated on serine 15) after gamma-irradiation. We have found the amount of phosphorylated p53 to be homogenously increased after irradiation by the doses of 0.5 to 7.5 Gy. The dose-dependent response was pronounced especially after the doses up to 3.0 Gy. The presented data indicate that p53 phosphorylated on serine 15 might be used as a potential biodosimetric marker.

  7. Gamma radiation-induced conditioned taste aversions in rats: A comparison of the protective effects of area postrema lesions with differing doses of radiation

    SciTech Connect

    Ossenkopp, K.P.; Giugno, L. )

    1989-10-01

    Lesions which destroy the area postrema (AP) and damage the adjacent nucleus of the solitary tract (NTS) attenuate or abolish conditioned taste aversions (CTA) induced by a variety of pharmacological agents as well as exposure to radiation. In the present experiment, 4 groups of male rats received lesions of AP and 4 groups were given sham lesions. One sham-lesioned and one AP-lesioned group were given a single pairing of 1-hr access to a novel 0.10% sodium saccharin solution followed immediately with exposure to 0, 100, 200, or 400 rad of gamma radiation, respectively. Four days later all groups were given daily two-bottle preference tests (saccharin vs. water) on 4 consecutive days. The sham-lesioned groups exposed to the radiation (100, 200, or 400 rad) developed profound aversions to the saccharin on all test days (p less than 0.001). In contrast, all of the AP-lesioned groups as well as the sham-irradiated (0 rad) sham-lesioned group exhibited strong, comparable (p greater than 0.30) preferences for saccharin. Thus, lesion of AP abolished the radiation-induced CTA at all dose levels of radiation. These results raise the possibility of pharmacological intervention at the level of AP to prevent radiation-induced CTA in cancer patients undergoing radiation therapy.

  8. Ceramic Matrix Composites Performances Under High Gamma Radiation Doses

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  9. Gamma radiation induced changes in nuclear waste glass containing Eu

    NASA Astrophysics Data System (ADS)

    Mohapatra, M.; Kadam, R. M.; Mishra, R. K.; Kaushik, C. P.; Tomar, B. S.; Godbole, S. V.

    2011-10-01

    Gamma radiation induced changes were investigated in sodium-barium borosilicate glasses containing Eu. The glass composition was similar to that of nuclear waste glasses used for vitrifying Trombay research reactor nuclear waste at Bhabha Atomic Research Centre, India. Photoluminescence (PL) and electron paramagnetic resonance (EPR) techniques were used to study the speciation of the rare earth (RE) ion in the matrix before and after gamma irradiation. Judd-Ofelt ( J- O) analyses of the emission spectra were done before and after irradiation. The spin counting technique was employed to quantify the number of defect centres formed in the glass at the highest gamma dose studied. PL data suggested the stabilisation of the trivalent RE ion in the borosilicate glass matrix both before and after irradiation. It was also observed that, the RE ion distributes itself in two different environments in the irradiated glass. From the EPR data it was observed that, boron oxygen hole centre based radicals are the predominant defect centres produced in the glass after irradiation along with small amount of E’ centres. From the spin counting studies the concentration of defect centres in the glass was calculated to be 350 ppm at 900 kGy. This indicated the fact that bulk of the glass remained unaffected after gamma irradiation up to 900 kGy.

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

    NASA Astrophysics Data System (ADS)

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

    2005-04-01

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

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

    PubMed

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

    2010-01-01

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

  12. High Dose Gamma Radiation Selectively Reduces GABAA-slow Inhibition

    PubMed Central

    Dagne, Beza A; Sunay, Melis K; Cayla, Noëlie S; Ouyang, Yi-Bing; Knox, Susan J; Giffard, Rona G; Adler, John R.

    2017-01-01

    Studies on the effects of gamma radiation on brain tissue have produced markedly differing results, ranging from little effect to major pathology, following irradiation. The present study used control-matched animals to compare effects on a well characterized brain region following gamma irradiation. Male Sprague-Dawley rats were exposed to 60 Gy of whole brain gamma radiation and, after 24-hours, 48-hours, and one-week periods, hippocampal brain slices were isolated and measured for anatomical and physiological differences. There were no major changes observed in tissue appearance or evoked synaptic responses at any post-irradiation time point. However, exposure to 60 Gy of irradiation resulted in a small, but statistically significant (14% change; ANOVA p < 0.005; n = 9) reduction in synaptic inhibition seen at 100 ms, indicating a selective depression of the gamma-aminobutyric acid (GABAA) slow form of inhibition. Population spike (PS) amplitudes also transiently declined by ~ 10% (p < 0.005; n = 9) when comparing the 24-hour group to sham group. Effects on PS amplitude recovered to baseline 48 hour and one week later. There were no obvious negative pathological effects; however, a subtle depression in circuit level inhibition was observed and provides evidence for ‘radiomodulation’ of brain circuits.

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

    PubMed

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

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  15. Mitigation of whole-body gamma radiation-induced damages by Clerodendron infortunatum in mammalian organisms.

    PubMed

    Chacko, Tiju; Menon, Aditya; Majeed, Teeju; Nair, Sivaprabha V; John, Nithu Sara; Nair, Cherupally Krishnan Krishnan

    2016-11-17

    Several phytoceuticals and extracts of medicinal plants are reported to mitigate deleterious effects of ionizing radiation. The potential of hydro-alcoholic extract of Clerodendron infortunatum (CIE) for providing protection to mice exposed to gamma radiation was investigated. Oral administration of CIE bestowed a survival advantage to mice exposed to lethal doses of gamma radiation. Radiation-induced depletion of the total blood count and bone marrow cellularity were prevented by treatment with CIE. Damage to the cellular DNA (as was evident from the comet assay and the micronucleus index) was also found to be decreased upon CIE administration. Radiation-induced damages to intestinal crypt cells was also reduced by CIE. Studies on gene expression in intestinal cells revealed that there was a marked increase in the Bax/Bcl-2 ratio in mice exposed to whole-body 4 Gy gamma radiation, and that administration of CIE resulted in significant lowering of this ratio, suggestive of reduction of radiation-induced apoptosis. Also, in the intestinal tissue of irradiated animals, following CIE treatment, levels of expression of the DNA repair gene Atm were found to be elevated, and there was reduction in the expression of the inflammatory Cox-2 gene. Thus, our results suggest a beneficial use of Clerodendron infortunatum for mitigating radiation toxicity.

  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

    SciTech Connect

    Kim, Tae Rim; Lee, Hee Min; Lee, So Yong; Kim, Eun Jin; Kim, Kug Chan; Paik, Sang Gi; Cho, Eun Wie; Kim, In Gyu

    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. Gamma Radiation-Induced Damage in the Zinc Finger of the Transcription Factor IIIA

    PubMed Central

    Miao, YuJi; Hu, XiaoDan; Min, Rui; Liu, PeiDang; Zhang, HaiQian

    2016-01-01

    A zinc finger motif is an element of proteins that can specifically recognize and bind to DNA. Because they contain multiple cysteine residues, zinc finger motifs possess redox properties. Ionizing radiation generates a variety of free radicals in organisms. Zinc finger motifs, therefore, may be a target of ionizing radiation. The effect of gamma radiation on the zinc finger motifs in transcription factor IIIA (TFIIIA), a zinc finger protein, was investigated. TFIIIA was exposed to different gamma doses from 60Co sources. The dose rates were 0.20 Gy/min and 800 Gy/h, respectively. The binding capacity of zinc finger motifs in TFIIIA was determined using an electrophoretic mobility shift assay. We found that 1000 Gy of gamma radiation impaired the function of the zinc finger motifs in TFIIIA. The sites of radiation-induced damage in the zinc finger were the thiol groups of cysteine residues and zinc (II) ions. The thiol groups were oxidized to form disulfide bonds and the zinc (II) ions were indicated to be reduced to zinc atoms. These results indicate that the zinc finger motif is a target domain for gamma radiation, which may decrease 5S rRNA expression via impairment of the zinc finger motifs in TFIIIA. PMID:27803644

  18. Gamma-radiation-induced wood-plastic composites from Syrian tree species

    NASA Astrophysics Data System (ADS)

    Bakraji, Elias Hanna; Salman, Numan; Al-kassiri, Haroun

    2001-05-01

    Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a 60Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used.

  19. Gamma radiation-induced blue shift of resonance peaks of Bragg gratings in pure silica fibres

    SciTech Connect

    Faustov, A V; Mégret, P; Wuilpart, M; Kinet, D; Gusarov, A I; Zhukov, A V; Novikov, S G; Svetukhin, V V; Fotiadi, A A

    2016-02-28

    We report the first observation of a significant gamma radiation-induced blue shift of the reflection/transmission peak of fibre Bragg gratings inscribed into pure-silica core fibres via multiphoton absorption of femtosecond pulses. At a total dose of ∼100 kGy, the shift is ∼20 pm. The observed effect is attributable to the ionising radiation-induced decrease in the density of the silica glass when the rate of colour centre formation is slow. We present results of experimental measurements that provide the key parameters of the dynamics of the gratings for remote dosimetry and temperature sensing. (laser crystals and braggg ratings)

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

    NASA Astrophysics Data System (ADS)

    Andjelković, Marko S.; Ristić, Goran S.; Jakšić, Aleksandar B.

    2015-02-01

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

  1. A paracrine signal mediates the cell transformation response to low dose gamma radiation in JB6 cells

    SciTech Connect

    Weber, Thomas J.; Siegel, Robert W.; Markillie, Lye Meng; Chrisler, William B.; Lei, Xingye C.; Colburn, Nancy H.

    2005-05-01

    Radiation at low doses (? 50 cGy) can enhance or reduce tumor incidence in the mouse skin multistage model of carcinogenesis, depending on the timing of radiation exposure relative to chemical initiator. Here we have used JB6 mouse epidermal cells, an in vitro model of late stage tumor promotion, to evaluate the effects of low dose gamma radiation on cell transformation response. JB6 cells were isolated from the DNA-dependent Protein Kinase (DNA-PK) deficient Balb/c mouse that exhibits an unusually sensitive mammary tumor response to ionizing radiation. Exposure of JB6 cells to low dose (2-20 cGy) gamma radiation increased cell transformation response in a dose- and cell density-dependent fashion. JB6 cells were transfected with a membrane targeted enhanced yellow fluorescent protein (EYFP-membrane) and used as bystander cells in a co-culture model. Co-culture of 10 cGy irradiated JB6 cells with na?ve EYFP-membrane cells resulted in a significant increase in EYFP-expressing colonies, relative to co-cultures of sham exposed P+ cells/na?ve EYFP-membrane cells. In contrast, low dose gamma radiation (20 cGy) reduced tumor promoter (epidermal growth factor; 12-O-tetradecanoyl phorbol-13-acetate)-induced transformation response and cell survival in a clonogenic assay to a comparable extent (40%). Our results demonstrate different selective pressures depending on whether low dose radiation modulated the cell transformation response of irradiated or bystander cells, or whether irradiation occurred in conjunction with tumor promoter treatment. The co-culture system developed here is a promising model to define positive and negative selective pressures induced by low dose radiation in a DNA damage repair deficient context that are relevant to carcinogenesis responses.

  2. Radiation-Induced Central Nervous System Death - A study of the Pathologic Findings in Monkeys Irradiated with Massive Doses of Cobalt-60 (Gamma) Radiation

    DTIC Science & Technology

    1959-04-01

    U.S. DEPARTMENT OF COMMERCE National Technical Information Service AD-AO36 168 RADIATION-INDUCED CENTRAL NERVOUS SYSTEM DEATH - A STUDY OF THE...ý." - ý " . :..’ýý.ý-. .. , . ý 4 ý .. -- ’ý.- -!:;:ý’,. 1,ý,-: WJiAUOK4KOUED CENTRAL NERVOUS SYSTEM NT A Study of the Pathologic Findings in...University SCHOOL OF AVIATION MEDICINE, USAF Randolph AFB, Texas April 1959 7757-. AdIAIONH-INDUCED CENTRAL NEVOUS $Y$194 DUTH A Study of the Pathologic

  3. Determination of canine dose conversion factors in mixed neutron and gamma radiation fields. Technical report

    SciTech Connect

    Torres, B.A.; Bhatt, R.C.; Myska, J.C.; Holland, B.K.

    1996-07-01

    The primary objective of mixed-field neutron/gamma radiation dosimetry in canine irradiation experiments conducted at the Armed Forces Radiobiology Research Institute (AFRRI) is to determine the absorbed midline tissue dose (MLT) at the region of interest in the canine. A dose conversion factor (DCF) can be applied to free-in-air (FIA) dose measurements to estimate the MLT doses to canines. This report is a summary of the measured DCFs that were used to determine the MLT doses in canines at AFRRI from 1979 to 1992.

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

    PubMed

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

    2012-11-01

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

  5. A meta-analysis of leukaemia risk from protracted exposure to low-dose gamma radiation

    PubMed Central

    Schubauer-Berigan, M K

    2010-01-01

    Context More than 400 000 workers annually receive a measurable radiation dose and may be at increased risk of radiation-induced leukaemia. It is unclear whether leukaemia risk is elevated with protracted, low-dose exposure. Objective We conducted a meta-analysis examining the relationship between protracted low-dose ionising radiation exposure and leukaemia. Data sources Reviews by the National Academies and United Nations provided a summary of informative studies published before 2005. PubMed and Embase databases were searched for additional occupational and environmental studies published between 2005 and 2009. Study selection We selected 23 studies that: (1) examined the association between protracted exposures to ionising radiation and leukaemia excluding chronic lymphocytic subtype; (2) were a cohort or nested case–control design without major bias; (3) reported quantitative estimates of exposure; and (4) conducted exposure–response analyses using relative or excess RR per unit exposure. Methods Studies were further screened to reduce information overlap. Random effects models were developed to summarise between-study variance and obtain an aggregate estimate of the excess RR at 100 mGy. Publication bias was assessed by trim and fill and Rosenthal's file drawer methods. Results We found an ERR at 100 mGy of 0.19 (95% CI 0.07 to 0.32) by modelling results from 10 studies and adjusting for publication bias. Between-study variance was not evident (p=0.99). Conclusions Protracted exposure to low-dose gamma radiation is significantly associated with leukaemia. Our estimate agreed well with the leukaemia risk observed among exposed adults in the Life Span Study (LSS) of atomic bomb survivors, providing increased confidence in the current understanding of leukaemia risk from ionising radiation. However, unlike the estimates obtained from the LSS, our model provides a precise, quantitative summary of the direct estimates of excess risk from studies of

  6. Inhibition of gamma-radiation induced DNA damage in plasmid pBR322 by TMG, a water-soluble derivative of vitamin E.

    PubMed

    Rajagopalan, Rema; Wani, Khalida; Huilgol, Nagaraj G; Kagiya, Tsutomu V; Nair, Cherupally K Krishnan

    2002-06-01

    Alpha-tocopherol monoglucoside (TMG), a water-soluble derivative of alpha-tocopherol, has been examined for its ability to protect DNA against radiation-induced strand breaks. Gamma radiation, up to a dose of 6 Gy (dose rate, 0.7 Gy/minute), induced a dose-dependent increase in single strand breaks (SSBs) in plasmid pBR322 DNA. TMG inhibited the formation of gamma-radiation induced DNA single strand breaks (SSBs) in a concentration-dependent manner; 500 microM of TMG protected the single strand breaks completely. It also protected thymine glycol formation induced by gamma-radiation in a dose-dependent manner, based on an estimation of thymine glycol by HPLC.

  7. The effect of low doses of gamma radiation on the electrophysical properties of mesoporous silicon

    NASA Astrophysics Data System (ADS)

    Bilenko, D. I.; Galushka, V. V.; Zharkova, E. A.; Sidorov, V. I.; Terin, D. V.; Khasina, E. I.

    2017-02-01

    The effect of low exposure doses (5-40 kR) of gamma radiation on the electrical properties of structures based on a mesoporous silicon (SiMP) layer is investigated. It is demonstrated that the conductivity of the SiMP layer increases, the Fermi level shifts, and the trap density changes in gamma-irradiated Al/SiMP/ p-Si/Al structures. Long-term stable switched-state memory in the region of the I-V curve hysteresis is revealed. This effect is controlled by the irradiation dose.

  8. Decomposition Byproducts Induced by Gamma Radiation and their Toxicity: the Case of 2-Nitrophenol.

    PubMed

    Alsager, Omar A; Basfar, Ahmed A; Muneer, Majid

    2017-04-10

    The induced degradation and detoxification of 2-nitrophenol (2-NP) in aqueous media by gamma irradiation were carefully evaluated in this study. Gamma radiation at absorbed doses as low as 20 kGy was able to degrade 2-NP to reach a removal of at least 85% across the investigated range of concentration (50-150 ppm). 2-NP breaks down to aromatic based compounds with increasing number of byproducts upon increasing the radiation treatment from the absorbed dose of 50% decomposition (D50) to the absorbed dose of 90% decomposition (D90), after which no byproducts could be detected indicating the formation of undetectable aliphatic hydrocarbons, insoluble, or volatile byproducts. Toxicology studies showed that the degradation of 2-NP under absorbed doses up to D90 resulted in a more toxic byproducts than the parent compound and a remarkable reduction in the toxicity was observed with the irradiated samples with absorbed doses above D90. Furthermore, the effect of other experimental conditions on the decomposition efficiency of 2-NP were investigated along with their influence on the toxicity. Varying the pH of the media to acidic or basic conditions did not significantly alter the degradation behavior of 2-NP. However, a notable improvement of the detoxification was associated with the samples of acidic pH. Adding 0.5% of H2O2 to 2-NP solutions had a positive effect by reducing D90 by a factor of nine and diminishing the toxicity by two folds. The results of the present study pave the way to the real application of gamma radiation and similar technologies to decompose contaminates such as 2-NP of high toxicity, poor biodegradability and carcinogenic and recalcitrant properties.

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

    PubMed

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

    2010-04-06

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

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

    PubMed Central

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

    2010-01-01

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

  11. The effect of high dose rate transient gamma radiation on high-energy optical fibers

    NASA Astrophysics Data System (ADS)

    Akinci, A.; Bowden, M. D.; Cheeseman, M. C.; Knowles, S. L.; Meister, D. C.; Pecak, S. N.; Simmons Potter, K.

    2009-08-01

    High power laser systems have a number of uses in a variety of scientific and defense applications, for example laser induced breakdown spectroscopy (LIBS) or laser-triggered switches. In general, high power optical fibers are used to deliver the laser energy from the source to the target in preference to free space beams. In certain cases, such as nuclear reactors, these optical systems are expected to operate in ionizing radiation environments. In this paper, a variety of modern, currently available commercial off-the-shelf (COTS) optical fiber designs have been assessed for successful operation in the transient gamma radiation environment produced by the HERMES III accelerator at Sandia National Laboratories, USA. The performance of these fibers was evaluated for high (~1 MW) and low (<1 W) optical power transmission during high dose rate, high total dose gamma irradiation. A significant reduction in low optical power transmission to 32% of maximum was observed for low OH- content fibers, and 35% of maximum for high OH- fibers. The high OH- fibers were observed to recover to 80% transmission within 1 μs and 100% transmission within 1 ms. High optical power transmission losses followed generally similar trends to the low optical power transmission losses, though evidence for an optical power dependent recovery was observed. For 10-20 mJ, 15 ns laser pulses, around 46% was transmitted coincident with the radiation pulse, recovering to 70% transmission within 40 ns of the radiation pulse. All fibers were observed to completely recover within a few minutes for high optical powers. High optical power densities in excess of 1 GW/cm2 were successfully transmitted during the period of highest loss without any observed damage to the optical fibers.

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

    PubMed

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

    2014-11-01

    Due to the production of free radicals, gamma radiation may pose a hazard to living organisms. The high-dose radiation effects have been extensively studied, whereas the ecotoxicity data on low-dose gamma radiation is still limited. The present study was therefore performed using Atlantic salmon (Salmo salar) to characterize effects of low-dose (15, 70 and 280 mGy) gamma radiation after short-term (48h) exposure. Global transcriptional changes were studied using a combination of high-density oligonucleotide microarrays and quantitative real-time reverse transcription polymerase chain reaction (qPCR). Differentially expressed genes (DEGs; in this article the phrase gene expression is taken as a synonym of gene transcription, although it is acknowledged that gene expression can also be regulated, e.g., at protein stability and translational level) were determined and linked to their biological meanings predicted using both Gene Ontology (GO) and mammalian ortholog-based functional analyses. The plasma glucose level was also measured as a general stress biomarker at the organism level. Results from the microarray analysis revealed a dose-dependent pattern of global transcriptional responses, with 222, 495 and 909 DEGs regulated by 15, 70 and 280 mGy gamma radiation, respectively. Among these DEGs, only 34 were commonly regulated by all radiation doses, whereas the majority of differences were dose-specific. No GO functions were identified at low or medium doses, but repression of DEGs associated with GO functions such as DNA replication, cell cycle regulation and response to reactive oxygen species (ROS) were observed after 280mGy gamma exposure. Ortholog-based toxicity pathway analysis further showed that 15mGy radiation affected DEGs associated with cellular signaling and immune response; 70mGy radiation affected cell cycle regulation and DNA damage repair, cellular energy production; and 280mGy radiation affected pathways related to cell cycle regulation and DNA

  13. Gamma radiation-induced synthesis and characterization of Polyvinylpyrrolidone nanogels

    NASA Astrophysics Data System (ADS)

    Ges, A. A.; Viltres, H.; Borja, R.; Rapado, M.; Aguilera, Y.

    2017-01-01

    Due to the importance of bioactive peptides, proteins and drug for pharmaceutical purpose, there is a growing interest for suitable delivery systems, able to increase their bioavailability and to target them to the desired location. Some of the most studied delivery systems involve encapsulation or entrapment of drugs into biocompatible polymeric devices. A multitude of techniques have been described for the synthesis of nanomaterials from polymers, however, the use of ionizing radiation (γ, e-), to obtain nano- and microgels polymer is characterized by the possibility of obtaining products with a high degree of purity. Although, in the world, electronic radiation is used for this purpose, gamma radiation has not been utilized for these purposes. In this paper is developed the formulation the formulation of Polyvinylpyrrolidone (PVP) nanogels synthesized by gamma radiation techniques, for their evaluation as potential system of drug delivery. Experiments were performed in absence of oxygen using aqueous solutions of PVP (0.05% -1%). Crosslinking reactions were carried out at 25° C in a gamma irradiation chamber with a 60Co source (MPX-γ 30). The Viscosimetry, Light Scattering, X-Ray Diffraction and Transmission Electron Microscopy (TEM), were used as characterization techniques.

  14. Study of bulk damage in high resistivity silicon detectors irradiated by high dose of {sup 60}Co {gamma}-radiation

    SciTech Connect

    Li, Z.; Li, C.J.

    1996-04-01

    High dose (> 200 Mrad) {gamma}-radiation induced displacement damage (or bulk damage) in high resistivity (6--10 k{Omega}-cm) silicon detectors has been studied. It has been found that detector bulk leakage current increases with {gamma} dose at a rate of 3.3 {times} 10{sup {minus}7} A/cm{sup 3}/Mrad. This introduction rate of bulk leakage current makes the introduction of generation centers by 210 Mrad of {gamma}-radiation comparable to that by 1 {times} 10{sup 12} n/cm{sup 2} of neutron radiation. Significant carrier removal (or donor removal), about 100%, was found in detectors irradiated to 215 Mrad. Space charge sign inversion (SCSI) (or type inversion) was observed in detectors irradiated to {ge} 215 Mrad using transient current technique (TCT). As many as seven deep levels have been observed by current deep level transient spectroscopy (I-DLTS). There was little or no annealing (or reverse annealing) for detectors irradiated to 215 Mrad. Some annealing for detectors irradiated to 500 Mrad have been observed.

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  16. Low doses of gamma radiation in the management of postharvest Lasiodiplodia theobromae in mangos

    PubMed Central

    Santos, Alice Maria Gonçalves; Lins, Severina Rodrigues Oliveira; da Silva, Josenilda Maria; de Oliveira, Sônia Maria Alves

    2015-01-01

    The postharvest life of mango is limited by the development of pathogens, especially fungi that cause rot, among which stands out the Lasiodiplodia theobromae. Several control methods have been employed to minimize the damages caused by this fungus, chemical control can leave residues to man and nature; physical control by the use of gamma radiation in combination with modified atmosphere and cold storage. The use of gamma radiation helps to reduce the severity of the pathogen assist in the ripening process of fruits, even at low doses (0.25, 0.35 and 0.45 kGy) chemical properties such as pH, soluble solids, acid ascorbic, titratable acidity and also the quality parameters of the pulp showed no damage that are ideal for trade and consumption of mangoes. This treatment can be extended for use in the management of diseases such as natural infections for penducular rot complex that has as one of L. theobroma pathogens involved. PMID:26413068

  17. Terrestrial gamma radiation dose rate in Ryukyu Islands, subtropical region of Japan.

    PubMed

    Furukawa, M; Kina, S; Shiroma, M; Shiroma, Y; Masuda, N; Motomura, D; Hiraoka, H; Fujioka, S; Kawakami, T; Yasuda, Y; Arakawa, K; Fukahori, K; Jyunicho, M; Ishikawa, S; Ohomoto, T; Shingaki, R; Akata, N; Zhuo, W; Tokonami, S

    2015-11-01

    In order to explain the distribution of natural radiation level in the Asia, in situ measurements of dose rate in air due to terrestrial gamma radiation have been conducted in a total of 21 islands that belong to Ryukyu Islands (Ryukyu Archipelago), subtropical rejoin of southwest Japan. Car-borne surveys have also been carried out in Okinawa-jima, the biggest island of the archipelago. Based on the results for these measurements, arithmetic mean, the maximum and the minimum of the dose rates at 1 m in height from the unpaved soil ground in the archipelago were estimated to be 47, 165 and 8 nGy h(-1), respectively. A comparative study of car-borne data obtained prior to and subsequent to the 2011 Fukushima nuclear accident, as for Okinawa-jima, indicated that the nuclear accident has no impact on the environmental radiation at the present time.

  18. Effect of curcumin analog on gamma-radiation-induced cellular changes in primary culture of isolated rat hepatocytes in vitro.

    PubMed

    Srinivasan, M; Sudheer, A Ram; Rajasekaran, K N; Menon, Venugopal P

    2008-10-22

    The present study was aimed to evaluate the radioprotective effect of curcumin analog, on gamma-radiation-induced toxicity in primary cultures of isolated rat hepatocytes. Hepatocytes were isolated from the liver of rats by collagenase perfusion. The DNA damage was analysed by single cell gel electrophoresis (comet assay). An increase in the severity of DNA damage was observed with the increase in gamma-radiation dose at 1-4 Gy in cultured rat hepatocytes. The levels of lipid peroxidative indices like thiobarbituric acid reactive substances (TBARSs) were increased significantly, whereas the levels of reduced glutathione (GSH) and antioxidant enzymes were significantly decreased in gamma-irradiated groups. The maximum damage to hepatocytes was observed at 4Gy gamma-irradiation. Pretreatment with different concentrations of curcumin analog (1.38, 6.91 and 13.82 microM) shows a significant decrease in the levels of TBARS and DNA damage. Pretreatment with curcumin analog prevents the loss of enzymic and non-enzymic antioxidants like GSH upon gamma-irradiation. The maximum protection of hepatocytes was observed at 6.91 microM of curcumin analog pretreatment. Thus, our result shows that pretreatment with curcumin analog protects the hepatocytes against gamma-radiation-induced cellular damage.

  19. Measurements of environmental terrestrial gamma radiation dose rate in three mountainous locations in the western region of Saudi Arabia

    SciTech Connect

    Al-Ghorabie, Fayez H.H. . E-mail: alghorabie_f@hotmail.com

    2005-06-01

    This paper describes measurements of external gamma radiation dose rate from terrestrial gamma-rays 1 m above the ground in three different mountainous locations in the western region of the Kingdom of Saudi Arabia. These locations are At-Taif city, Al-Hada village, and Ash-Shafa village. CaSO{sub 4}:Dy (TLD-900) thermoluminescent dosimeters were used for the detection of terrestrial gamma radiation at 40 different places in the three locations. The values of terrestrial gamma radiation dose rate measured ranged between 14 and 279 nGy h{sup -1} for the time interval from June 2001 to June 2002. The measured dose rate varied with the season of the year. The average gamma radiation dose rates were 468, 541, and 781 {mu}Gy y{sup -1} for At-Taif city, Al-Hada village, and Ash-Shafa village, respectively. The corresponding average absorbed doses to the population of the three locations were 328, 379, and 547 {mu}Sv y{sup -1}, respectively. The quality factor of 0.7 Sv Gy{sup -1} was applied in the calculations of the absorbed dose to humans.

  20. Gamma radiation induces hydrogen absorption by copper in water

    PubMed Central

    Lousada, Cláudio M.; Soroka, Inna L.; Yagodzinskyy, Yuriy; Tarakina, Nadezda V.; Todoshchenko, Olga; Hänninen, Hannu; Korzhavyi, Pavel A.; Jonsson, Mats

    2016-01-01

    One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories. PMID:27086752

  1. Gamma radiation induces hydrogen absorption by copper in water.

    PubMed

    Lousada, Cláudio M; Soroka, Inna L; Yagodzinskyy, Yuriy; Tarakina, Nadezda V; Todoshchenko, Olga; Hänninen, Hannu; Korzhavyi, Pavel A; Jonsson, Mats

    2016-04-18

    One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.

  2. Gamma radiation induces hydrogen absorption by copper in water

    NASA Astrophysics Data System (ADS)

    Lousada, Cláudio M.; Soroka, Inna L.; Yagodzinskyy, Yuriy; Tarakina, Nadezda V.; Todoshchenko, Olga; Hänninen, Hannu; Korzhavyi, Pavel A.; Jonsson, Mats

    2016-04-01

    One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.

  3. Gamma radiation measurements and dose rates in commercially-used natural tiling rocks (granites).

    PubMed

    Tzortzis, Michalis; Tsertos, Haralabos; Christofides, Stelios; Christodoulides, George

    2003-01-01

    The gamma radiation in samples of a variety of natural tiling rocks (granites) imported in Cyprus for use in the building industry was measured, employing high-resolution gamma-ray spectroscopy. The rock samples were pulverised, sealed in 1-l plastic Marinelli beakers, and measured in the laboratory with an accumulating time between 10 and 14 h each. From the measured gamma-ray spectra, activity concentrations were determined for (232)Th (range from 1 to 906 Bq kg(-1)), (238)U (from 1 to 588 Bq kg(-1)) and (40)K (from 50 to 1606 Bq kg(-1)). The total absorbed dose rates in air calculated from the concentrations of the three radionuclides ranged from 7 to 1209 nGy h(-1) for full utilization of the materials, from 4 to 605 nGy h(-1) for half utilization and from 2 to 302 nGy h(-1) for one quarter utilization. The total effective dose rates per person indoors were determined to be between 0.02 and 2.97 mSv y(-1) for half utilization of the materials. Applying dose criteria recently recommended by the EU for superficial materials, 25 of the samples meet the exemption dose limit of 0.3 mSv y(-1), two of them meet the upper dose limit of 1 mSv y(-1) and only one clearly exceeds this limit.

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

    SciTech Connect

    Devi, P.U.; Baskar, R.; Hande, M.P. )

    1994-04-01

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

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

    PubMed

    Karam, P A; Leslie, S A

    1999-12-01

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

  6. Influence of seed extract of Syzygium Cumini (Jamun) on mice exposed to different doses of gamma-radiation.

    PubMed

    Jagetia, Ganesh Chandra; Baliga, Manjeshwar Shrinath; Venkatesh, Ponemone

    2005-03-01

    The radioprotective activity of the hydroalcoholic extract of jamun seeds (SCE) was studied in mice exposed to different doses of gamma radiation. The mice were injected with 0, 5, 10, 20, 40, 60, 80, 100, 120, 140 or 160 mg/kg body weight of SCE, before exposure to 10 Gy of gamma radiation, to select the optimum dose of radiation protection. The 80 mg/kg SCE was found to offer highest protection, therefore, further studies were carried out using this dose. The drug was more effective when administered through the intraperitoneal route at equimolar doses than the oral route. Since higher survival was observed for the i.p. route (50%), than the oral route (29.2%), all other studies were carried out by injecting SCE intraperitoneally. The mice treated with 80 mg/kg body weight SCE intraperitoneally before exposure to 6, 7, 8, 9, 10 and 11 Gy of gamma radiation showed reduction in the symptoms of radiation sickness and mortality at all exposure doses and caused a significant increase in the animal survival when compared with the concurrent double distilled water (DDW) + irradiation group. The SCE treatment protected mice against the gastrointestinal as well as bone marrow deaths and the DRF was found to be 1.24.

  7. Effect of pretreatment with cysteamine on gamma-radiation-induced sister chromatid exchanges in mouse bone marrow cells in vivo

    SciTech Connect

    Mendiola-Cruz, M.T.; Morales-Ramirez, P.

    1989-04-01

    The effect of pretreatment with cysteamine on gamma-radiation-induced sister chromatid exchanges (SCEs) and on the mitotic index and average generation time was determined. Groups of mice were treated in one of the following regimens: (1) irradiated, (2) treated with cysteamine and irradiated, (3) treated with cysteamine only, or (4) left untreated. Intraperitoneal administration of cysteamine preceding gamma-radiation exposure protected against SCE induction. However, radioprotection was not reflected by change in the mitotic index or in the average generation time. The results suggest that, under the experimental conditions of this study, the SCEs are caused by free radicals produced by gamma radiation, but not the additional damage indices measured.

  8. Radioprotective effect of sesamol on gamma-radiation induced DNA damage, lipid peroxidation and antioxidants levels in cultured human lymphocytes.

    PubMed

    Prasad, N Rajendra; Menon, Venugopal P; Vasudev, V; Pugalendi, K V

    2005-05-05

    Sesamol pretreated (1, 5 and 10 microg/ml) lymphocytes were exposed to different doses of gamma-radiation, i.e., 1, 2 and 4 Gray (Gy) and the cellular changes were estimated by using cytokinesis blocked micronucleus assay (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Radiation significantly increased MN, DC frequencies, TBARS levels and decreased GSH and antioxidant enzyme levels in a dose dependent manner. The highest damage to lymphocytes was observed at 4 Gy irradiation. On the other hand, sesamol pretreatment significantly decreased MN, DC frequencies, TBARS levels and increased GSH levels and SOD, CAT and GPx activities in a concentration dependent manner. At 1 Gy irradiation all concentrations of sesamol (1, 5 and 10 microg/ml) significantly protects the lymphocytes from radiation damage. At 2 Gy irradiation 5 and 10 microg/ml of sesamol shows significant radioprotection. Since the highest damage was observed at 4 Gy irradiation both 1 and 5 microg/ml of sesamol pretreatment were not sufficient to protect the lymphocytes from radiation damage but 10 microg/ml of sesamol significantly (p<0.05) protects the lymphocytes from radiation effect. Thus, sesamol pretreatment gives significant protection to cultured human lymphocytes against gamma-radiation induced cellular damage. The possible mechanism involved in the radioprotective influence of sesamol is discussed.

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

    PubMed

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

    2005-12-01

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

  10. CARBON FIBRE COMPOSITE MATERIALS PRODUCED BY GAMMA RADIATION INDUCED CURING OF EPOXY RESINS

    SciTech Connect

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

    2008-08-28

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

  11. Protective effect of ferulic acid on gamma-radiation-induced micronuclei, dicentric aberration and lipid peroxidation in human lymphocytes.

    PubMed

    Prasad, N Rajendra; Srinivasan, M; Pugalendi, K V; Menon, Venugopal P

    2006-02-28

    In this study we examined radioprotective effect of ferulic acid (FA) on gamma radiation-induced dicentric aberration and lipid peroxidation with reference to alterations in cellular antioxidant status in cultured lymphocytes. To establish most effective protective support we used three different concentrations of FA (1, 5 and 10 microg/ml) and three different doses of gamma-radiation (1, 2 and 4 Gy). Treatment of lymphocytes with FA alone (at 10 microg/ml) gave no significant change in micronuclei (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) or glutathione peroxidase (GPx) activities when compared with normal lymphocytes; irradiation at 1, 2 and 4 Gy increased the MN and DC frequencies in a dose-dependent manner. Treatment with FA for 30 min before radiation exposure resulted in a significant decline of MN and DC yields as FA concentration increased. Compared to 1 Gy exposure alone, the extent to which FA (1 microg/ml) reduced the MN and DC yields was 75% and 50%, respectively. With 4 Gy irradiation, FA (10 microg/ml) decreased 45% MN and 25% DC frequencies. FA-pretreated lymphocytes (1, 5 and 10 microg/ml) showed progressively decreased TBARS levels after irradiation. Irradiation (1, 2 and 4 Gy) significantly decreased GSH levels, SOD, CAT and GPx activities in a dose-dependent manner. Pretreatment with 10 microg/ml of FA significantly (p<0.05) prevented the decreases in the radiation-induced GSH, SOD, CAT and GPx activities. These findings suggest potential use and benefit of FA as a radioprotector.

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  13. Investigation of gamma radiation induced changes in local structure of borosilicate glass by TDPAC and EXAFS

    NASA Astrophysics Data System (ADS)

    Kumar, Ashwani; Nayak, C.; Rajput, P.; Mishra, R. K.; Bhattacharyya, D.; Kaushik, C. P.; Tomar, B. S.

    2016-12-01

    Gamma radiation induced changes in local structure around the probe atom (Hafnium) were investigated in sodium barium borosilicate (NBS) glass, used for immobilization of high level liquid waste generated from the reprocessing plant at Trombay, Mumbai. The (NBS) glass was doped with 181Hf as a probe for time differential perturbed angular correlation (TDPAC) spectroscopy studies, while for studies using extended X-ray absorption fine structure (EXAFS) spectroscopy, the same was doped with 0.5 and 2 % (mole %) hafnium oxide. The irradiated as well as un-irradiated glass samples were studied by TDPAC and EXAFS techniques to obtain information about the changes (if any) around the probe atom due to gamma irradiation. TDPAC spectra of unirradiated and irradiated glasses were similar and reminescent of amorphous materials, indicating negligible effect of gamma radiation on the microstructure around Hafnium probe atom, though the quaqdrupole interaction frequency ( ω Q) and asymmetry parameter ( η) did show a marginal decrease in the irradiated glass compared to that in the unirradiated glass. EXAFS measurements showed a slight decrease in the Hf-O bond distance upon gamma irradiation of Hf doped NBS glass indicating densification of the glass matrix, while the cordination number around hafnium remains unchanged.

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

    NASA Astrophysics Data System (ADS)

    Bartoníček, B.; Plaček, V.; Hnát, V.

    2007-05-01

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

  15. Removing Noises Induced by Gamma Radiation in Cerenkov Luminescence Imaging Using a Temporal Median Filter

    PubMed Central

    Li, Yang; Zhan, Yonghua; Kang, Fei; Wang, Jing

    2016-01-01

    Cerenkov luminescence imaging (CLI) can provide information of medical radionuclides used in nuclear imaging based on Cerenkov radiation, which makes it possible for optical means to image clinical radionuclide labeled probes. However, the exceptionally weak Cerenkov luminescence (CL) from Cerenkov radiation is susceptible to lots of impulse noises introduced by high energy gamma rays generating from the decays of radionuclides. In this work, a temporal median filter is proposed to remove this kind of impulse noises. Unlike traditional CLI collecting a single CL image with long exposure time and smoothing it using median filter, the proposed method captures a temporal sequence of CL images with shorter exposure time and employs a temporal median filter to smooth a temporal sequence of pixels. Results of in vivo experiments demonstrated that the proposed temporal median method can effectively remove random pulse noises induced by gamma radiation and achieve a robust CLI image. PMID:27648450

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

    PubMed Central

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

    2009-01-01

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

  17. Lycopene as a natural protector against gamma-radiation induced DNA damage, lipid peroxidation and antioxidant status in primary culture of isolated rat hepatocytes in vitro.

    PubMed

    Srinivasan, M; Sudheer, A Ram; Pillai, K Raveendran; Kumar, P Raghu; Sudhakaran, P R; Menon, V P

    2007-04-01

    The present study was designed to evaluate the radioprotective effect of lycopene, a naturally occurring dietary carotenoid, on gamma-radiation induced toxicity in cultured rat hepatocytes. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), ceruloplasmin, vitamins A, E, C and uric acid. The DNA damage was analysed by single cell gel electrophoresis (comet assay). The increase in the severity of DNA damage was observed with the increase in gamma-radiation dose (1, 2 and 4 Gy) in cultured rat hepatocytes. TBARS were increased significantly whereas the levels of GSH, vitamins C, E and A, ceruloplasmin, uric acid and antioxidant enzymes were significantly decreased in gamma-irradiated groups. The maximum damage to hepatocytes was observed at 4 Gy irradiation. Pretreatment with lycopene (1.86, 9.31 and 18.62 microM) showed a significant decrease in the levels of TBARS and DNA damage. The antioxidant enzymes increased significantly along with the levels of GSH, vitamins A, E, C, uric acid and ceruloplasmin. The maximum protection of hepatocytes was observed at 9.31 muM of lycopene pretreatment. Thus, our results show that pretreatment with lycopene offers protection against gamma-radiation induced cellular damage and can be developed as an effective radioprotector during radiotherapy.

  18. Protection by pantothenol and beta-carotene against liver damage produced by low-dose gamma radiation.

    PubMed

    Slyshenkov, V S; Omelyanchik, S N; Moiseenok, A G; Petushok, N E; Wojtczak, L

    1999-01-01

    Rats were exposed to a total dose of 0.75 Gy of gamma radiation from a 60Co source, receiving three doses of 0.25 Gy at weekly intervals. During two days before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg beta-carotene per kg body mass. The animals were killed after the third irradiation session, and their blood and livers were analyzed. As found previously (Slyshenkov, V.S., Omelyanchik, S.N., Moiseenok, A.G., Trebukhina, R.V. & Wojtczak, L. (1998) Free Radical Biol. Med. 24, 894-899), in livers of animals not supplied with either pantothenol or beta-carotene and killed one hour after the irradiation, a large accumulation of lipid peroxidation products, as conjugated dienes, ketotrienes and thiobarbituric acid-reactive substances, could be observed. The contents of CoA, pantothenic acid, total phospholipids, total glutathione and GSH/GSSG ratio were considerably decreased, whereas the NAD/NADH ratio was increased. All these effects were alleviated in animals supplied with beta-carotene and were completely abolished in animals supplied with pantothenol. In the present paper, we extended our observations of irradiation effects over a period of up to 7 days after the last irradiation session. We found that most of these changes, with the exception of GSH/GSSG ratio, disappeared spontaneously, whereas supplementation with beta-carotene shortened the time required for the normalization of biochemical parameters. In addition, we found that the activities of glutathione reductase, glutathione peroxidase, catalase and NADP-dependent malate (decarboxylating) dehydrogenase ('malic enzyme') in liver were also significantly decreased one hour after irradiation but returned to the normal level within 7 days. Little or no decrease in these activities, already 1 h after the irradiation, could be seen in animals supplemented with either beta-carotene or pantothenol. It is concluded that pantothenol is an excellent radioprotective

  19. Comparative toxicity and micronuclei formation in Tribolium castaneum, Callosobruchus maculatus and Sitophilus oryzae exposed to high doses of gamma radiation.

    PubMed

    Ahmadi, Mehrdad; Mozdarani, Hossein; Abd-Alla, Adly M M

    2015-07-01

    The effects of gamma radiation on mortality and micronucleus formation in Tribolium castaneum Herbst, Callosobruchus maculatus (F.) and Sitophilus oryzae (L.) genital cells were evaluated. Two groups of healthy and active adult insects 1-3 and 8-10 days old were irradiated with various doses (50-200 Gy) gamma ray. Seven days post-irradiation; mortality rates and micronucleus formation were assessed in genital cells of the irradiated insects. The results show that with increasing gamma doses, the mortality rate of each species increased and T. castaneum and S. oryzae showed the low and high sensitivity respectively. It was shown that the micronucleus appearance in the tested insects had correlation with amount and intensity of radiation doses. Moreover our results indicate different levels in the genotoxicity of gamma radiation among the insects' genital cells under study. The frequency of micronuclei in genital cells of 1-3 days old insects exposed to 50 and 200 Gy were 12.6 and 38.8 Mn/1000 cells in T. castaneum, 20.8 and 46.8 Mn/1000 cells in C. maculatus and 16.8 and 57.2 Mn/1000 cells in S. oryzae respectively. A high sensitivity of the genital cells to irradiation exposure was seen in S. oryzae correlated with its high mortality rate compared with the other two species. These results might be indicative of inflicting chromosomal damage expressed as micronucleus in high mortality rates observed in the pest population; an indication of genotoxic effects of radiation on the studied species.

  20. Gamma radiation used as hygienization technique for foods does not induce viable but non-culturable state (VBNC) in Salmonella enterica subsp. enterica serovar Typhimurium.

    PubMed

    Saroj, Sunil; Shashidhar, R; Bandekar, Jayant

    2009-10-01

    Gamma radiation has been widely used for hygienization of food products. Whether gamma radiation stress induces VBNC state in Salmonella is of great concern. Therefore, the study was carried out to determine whether gamma radiation exposure induces VBNC state in Salmonella enterica subsp. enterica serovar Typhimurium (S. typhimurium). The parameters tested were culturability on agar medium, transcriptional activity by RT-PCR, cytoplasmic membrane integrity, and direct viable count using LIVE/DEAD BacLight bacterial viability kit. The LIVE/DEAD BacLight counts for S. typhimurium cells treated with 0.5 and 1.0 kGy radiation dose were 0.8 and 0.1% of the control, respectively. Plate counts for S. typhimurium cells treated with 0.5 and 1.0 kGy radiation dose were 0.7 and 0.05% of the control, respectively. No viable cells of S. typhimurium were detected by both plate count and LIVE/DEAD BacLight after radiation treatment with 2 kGy. No transcriptional activity was detected in cells treated with 2 kGy radiation dose. If there were VBNC cells present, then significant differences in the counts between the LIVE/DEAD BacLight microscopic counts and plate agar counts must be observed. No significant difference (P > 0.05) in the counts were observed. Thus, it can be concluded that treatment with 2 kGy results in complete killing and does not induce VBNC state in S. typhimurium.

  1. Gamma radiation field intensity meter

    DOEpatents

    Thacker, L.H.

    1994-08-16

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

  2. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H.

    1995-01-01

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

  3. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H.

    1994-01-01

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

  4. Gamma radiation field intensity meter

    SciTech Connect

    Thacker, L.H.

    1995-10-17

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

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

    NASA Astrophysics Data System (ADS)

    Plaza-Rosado, Heriberto

    1991-09-01

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

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

    NASA Technical Reports Server (NTRS)

    Plaza-Rosado, Heriberto

    1991-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  8. The combined effect of uranium and gamma radiation on biological responses and oxidative stress induced in Arabidopsis thaliana.

    PubMed

    Vanhoudt, Nathalie; Vandenhove, Hildegarde; Horemans, Nele; Wannijn, Jean; Van Hees, May; Vangronsveld, Jaco; Cuypers, Ann

    2010-11-01

    Uranium never occurs as a single pollutant in the environment, but always in combination with other stressors such as ionizing radiation. As effects induced by multiple contaminants can differ markedly from the effects induced by the individual stressors, this multiple pollution context should not be neglected. In this study, effects on growth, nutrient uptake and oxidative stress induced by the single stressors uranium and gamma radiation are compared with the effects induced by the combination of both stressors. By doing this, we aim to better understand the effects induced by the combined stressors but also to get more insight in stressor-specific response mechanisms. Eighteen-day-old Arabidopsis thaliana seedlings were exposed for 3 days to 10 muM uranium and 3.5 Gy gamma radiation. Gamma radiation interfered with uranium uptake, resulting in decreased uranium concentrations in the roots, but with higher transport to the leaves. This resulted in a better root growth but increased leaf lipid peroxidation. For the other endpoints studied, effects under combined exposure were mostly determined by uranium presence and only limited influenced by gamma presence. Furthermore, an important role is suggested for CAT1/2/3 gene expression under uranium and mixed stressor conditions in the leaves.

  9. Gamma radiation at a human relevant low dose rate is genotoxic in mice

    PubMed Central

    Graupner, Anne; Eide, Dag M.; Instanes, Christine; Andersen, Jill M.; Brede, Dag A.; Dertinger, Stephen D.; Lind, Ole C.; Brandt-Kjelsen, Anicke; Bjerke, Hans; Salbu, Brit; Oughton, Deborah; Brunborg, Gunnar; Olsen, Ann K.

    2016-01-01

    Even today, 70 years after Hiroshima and accidents like in Chernobyl and Fukushima, we still have limited knowledge about the health effects of low dose rate (LDR) radiation. Despite their human relevance after occupational and accidental exposure, only few animal studies on the genotoxic effects of chronic LDR radiation have been performed. Selenium (Se) is involved in oxidative stress defence, protecting DNA and other biomolecules from reactive oxygen species (ROS). It is hypothesised that Se deficiency, as it occurs in several parts of the world, may aggravate harmful effects of ROS-inducing stressors such as ionising radiation. We performed a study in the newly established LDR-facility Figaro on the combined effects of Se deprivation and LDR γ exposure in DNA repair knockout mice (Ogg1−/−) and control animals (Ogg1+/−). Genotoxic effects were seen after continuous radiation (1.4 mGy/h) for 45 days. Chromosomal damage (micronucleus), phenotypic mutations (Pig-a gene mutation of RBCCD24−) and DNA lesions (single strand breaks/alkali labile sites) were significantly increased in blood cells of irradiated animals, covering three types of genotoxic activity. This study demonstrates that chronic LDR γ radiation is genotoxic in an exposure scenario realistic for humans, supporting the hypothesis that even LDR γ radiation may induce cancer. PMID:27596356

  10. Gamma radiation at a human relevant low dose rate is genotoxic in mice

    NASA Astrophysics Data System (ADS)

    Graupner, Anne; Eide, Dag M.; Instanes, Christine; Andersen, Jill M.; Brede, Dag A.; Dertinger, Stephen D.; Lind, Ole C.; Brandt-Kjelsen, Anicke; Bjerke, Hans; Salbu, Brit; Oughton, Deborah; Brunborg, Gunnar; Olsen, Ann K.

    2016-09-01

    Even today, 70 years after Hiroshima and accidents like in Chernobyl and Fukushima, we still have limited knowledge about the health effects of low dose rate (LDR) radiation. Despite their human relevance after occupational and accidental exposure, only few animal studies on the genotoxic effects of chronic LDR radiation have been performed. Selenium (Se) is involved in oxidative stress defence, protecting DNA and other biomolecules from reactive oxygen species (ROS). It is hypothesised that Se deficiency, as it occurs in several parts of the world, may aggravate harmful effects of ROS-inducing stressors such as ionising radiation. We performed a study in the newly established LDR-facility Figaro on the combined effects of Se deprivation and LDR γ exposure in DNA repair knockout mice (Ogg1‑/‑) and control animals (Ogg1+/‑). Genotoxic effects were seen after continuous radiation (1.4 mGy/h) for 45 days. Chromosomal damage (micronucleus), phenotypic mutations (Pig-a gene mutation of RBCCD24‑) and DNA lesions (single strand breaks/alkali labile sites) were significantly increased in blood cells of irradiated animals, covering three types of genotoxic activity. This study demonstrates that chronic LDR γ radiation is genotoxic in an exposure scenario realistic for humans, supporting the hypothesis that even LDR γ radiation may induce cancer.

  11. Induced of plastid mutations in soybean plant (Glycine max L. Merrill) with gamma radiation and determination with RAPD.

    PubMed

    Atak, Cimen; Alikamanoğlu, Sema; Açik, Leyla; Canbolat, Yasemin

    2004-11-22

    The aim of our study was to induce with radiation of atrazine resistant and tolerated mutants in Coles, Amsoy-71 and 1937 soybean varieties. Atrazine that is photosynthetic inhibitor is the most important herbicide of S-triazin group, and shows toxic effect on soybean plant. For the improvement of the atrazine resistant plants with mutation breeding, the seeds belonging to the three varieties were irradiated with 200 Gy of gamma radiation dose. The irradiated seeds were sown in the field and at the end of harvesting season, every pod at node situated on the main stem was picked up separately and M2 generations were obtained. At the plants, which were obtained from M2 generation, chlorophyll mutants were determined and atrazine selection was made. The percentage of chlorophyll mutants for Amsoy-71, Coles and 1937 soybean varieties were found as 1.07, 1.48 and 1.32, respectively. At the end of atrazine selection, the percentages of atrazine resistant plants for Amsoy-71, Coles and 1937 soybean varieties were 0.80, 0.60 and 0.53, respectively. The percentages of atrazine tolerated plants were 1.07, 1.18 and 1.05, respectively as well. In our research; the differences among the mutants replying to atrazine in various concentrations were examined by using RAPD procedure as the molecular marker techniques in comparison with polymorphism. In the study done by using 14 primers; according to the amplification results, the differences between atrazine resistant plants were shown.

  12. Short Communication: Rheological properties of blood serum of rats after irradiation with different gamma radiation doses in vivo.

    PubMed

    Abdelhalim, Mohamed Anwar K; Moussa, Sherif Aa; Ms, Al-Ayed

    2016-01-01

    The blood serum rheological properties open the door to find suitable radio-protectors and convenient therapy for many cases of radiation exposure. The present study aimed to investigate the rheological properties of rat blood serum at wide range of shear rates after whole body irradiation with different gamma radiation doses in vivo. Healthy male rats were divided into five groups; one control group and 4 irradiated groups. The irradiation process was carried out using Co60 source with dose rate of 0.883cG/sec. Several rheological parameters were measured using Brookfield LVDV-III Programmable rheometer. A significant increase in viscosity and shear stress was observed with 25 and 50Gy corresponding to each shear rate compared with the control; while a significant decrease observed with 75 and 100Gy. The viscosity exhibited a Non-Newtonian behaviour with the shear rate while shear stress values were linearly related with shear rate. The decrease in blood viscosity might be attributed to changes in molecular weight, pH sensitivity and protein structure. The changes in rheological properties of irradiated rats' blood serum might be attributed to destruction changes in the haematological and dimensional properties of rats' blood products.

  13. Assessment of terrestrial gamma radiation doses for some Egyptian granite samples.

    PubMed

    El Arabi, A M; Ahmed, N K; Salahel Din, K

    2008-01-01

    External exposures of population to ionising radiation due to naturally occurring radionuclides in sixty-three granite samples from three different locations in south eastern desert of Egypt were considered in this article. Average outdoor gamma dose rates in air were 190, 290 and 330 nGy h(-1) for Elba, Qash Amir and Hamra Dome granites, respectively. The corresponding doses in indoor air are 270, 400 and 470 nGy h(-1), respectively. These average values give rise to annual effective dose (outdoor, indoor and in total) 0.24, 1.4 and 1.6 mSv for Elba granite. For Qash Amir and Hamra Dome granites the corresponding values were 0.35, 2 and 2.3 mSv and 0.41, 2.3 and 2.7 mSv, respectively.

  14. Calculation of gamma radiation dose rate and radon concentration due to granites used as building materials in Iran.

    PubMed

    Abbasi, A

    2013-07-01

    Natural radioactivity concentrations in granite building materials that are commonly used in Iran have been surveyed by using a gamma-ray spectrometry system, using a high-purity germanium detector. Health hazards from gamma radiation doses due to granite and radon concentration have been calculated. The dose rate of exposure from granite building materials on humans is obtained as a result of an external exposure from gamma-emitting radionuclides in the granites. Another mode of exposure is from the inhalation of the decay products of (222)Ra and (220)Ra. The average concentrations of (232)Th, (226)Ra and (40)K were in the ranges of 6.5-172.2, 3.8-94.2 and 556.9-1539.2 Bq kg(-1), respectively. The radon exhalation rates have also been studied and values were in the range of 0.32 ± 0.01 to 7.86 ± 1.65 Bq m(-2) h(-1). For two models of standard living rooms (5.0 m × 4.0 m area; 2.8 m), the radon concentration (Ci) and the absorbed dose (D) rates were calculated and the results were found to be 10.64-29.32 Bq m(-3), 3.84-68.02 nGy h(-1) and 0.02-0.33 mSv y(-1) for Model 1, 10.07-15.38 Bq m(-3) and 2.29-39.99 nGy h(-1) for Model 2, respectively. According to our estimations, mechanical ventilation systems (λν = 0.5 h(-1)) in a room all granite samples would produce radon concentration <100 Bq m(-3).

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

    SciTech Connect

    Billiard, Fabienne; Buard, Valerie; Benderitter, Marc; Linard, Christine

    2011-07-01

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

  16. Gamma radiation effects on seed germination, growth and pigment content, and ESR study of induced free radicals in maize (Zea mays).

    PubMed

    Marcu, Delia; Damian, Grigore; Cosma, Constantin; Cristea, Victoria

    2013-09-01

    The effects of gamma radiation are investigated by studying plant germination, growth and development, and biochemical characteristics of maize. Maize dry seeds are exposed to a gamma source at doses ranging from 0.1 to 1 kGy. Our results show that the germination potential, expressed through the final germination percentage and the germination index, as well as the physiological parameters of maize seedlings (root and shoot lengths) decreased by increasing the irradiation dose. Moreover, plants derived from seeds exposed at higher doses (≤0.5 kGy) did not survive more than 10 days. Biochemical differences based on photosynthetic pigment (chlorophyll a, chlorophyll b, carotenoids) content revealed an inversely proportional relationship to doses of exposure. Furthermore, the concentration of chlorophyll a was higher than chlorophyll b in both irradiated and non-irradiated seedlings. Electron spin resonance spectroscopy used to evaluate the amount of free radicals induced by gamma ray treatment demonstrates that the relative concentration of radiation-induced free radicals depends linearly on the absorbed doses.

  17. Evolutionary mechanism of the defects in the fluoride-containing phosphate based glasses induced by gamma radiation

    NASA Astrophysics Data System (ADS)

    Wang, Pengfei; He, Quanlong; Lu, Min; Li, Weinan; Peng, Bo

    2016-01-01

    In the laser driven inertial confinement fusion (ICF) experimental target chamber, like the 3ω (351 nm) laser irradiation, the irradiation of gamma ray and X-rays, will also cause the formation and increase of various defects in the investigated series of fluoride-containing phosphate based glasses that have potential use in novel high performance color separation optics. The induced defects contribute to the increase of absorption in the UV region, which will make the UV performance of these laser glasses deteriorated. Some of the induced defects can be bleached to some extent through the subsequent thermal treatment process, resulting from the release and capture of the electrons in conduction band. Through the gamma radiation and post-heat treatment experiments, a general model of the evolutionary mechanism of the defects in these fluoride-containing phosphate based glasses was proposed.

  18. Effect of gamma radiation on Brugia L3 development in vivo and the kinetics of granulomatous inflammation induced by these parasites.

    PubMed

    Nasarre, C; Rao, U R; Coleman, S U; Klei, T R

    1997-12-01

    Previous studies have shown that the downregulation of parasite-specific cellular immune response in Brugia-infected jirds requires viable worms but is not dependent on microfilariae (MF) for either induction or maintenance of this phenomenon. To clarify further which life cycle stages induce filarial hyporesponsiveness, jirds were infected intraperitoneally with third stage larvae (L3) exposed to 0, 15, 25, 35, 45, or 90 krad of gamma radiation to differentially alter L3 development. Necropsies were performed at 7, 14, 28, and 118 days postinoculation (DPI). The degree of parasite development, intraperitoneal inflammation, and pulmonary granulomatous inflammation (PGRN) to parasite antigen-coated beads embolized in the lungs were monitored at the time of necropsy. Parasite survival and worm lengths were inversely related to the irradiation dose. Gamma radiation at 35, 45, or 90 krad prevented larval molt to the adult stage. Some parasites irradiated with 15 or 25 krad developed beyond fourth stage larvae (L4) to infertile adult females. The PGRN peaked at 14 DPI in all infected groups. Downregulation of the PGRN occurred after 14 DPI in groups that received nonirradiated L3 or L3 irradiated with 15 krad. No significant decrease of the PGRN occurred in groups that received parasites irradiated with more than 15 krad. Significant peritoneal inflammation as indicated by an increase in macrophages occurred only in jirds that received nonirradiated L3. These data demonstrate the importance of the adult stages in inducing downmodulation in the absence of MF and suggest that the L4 may also play a role in the induction of this phenomenon. An alternate conclusion is that parasite burden and not developmental stage is important in the induction of this hyporesponsive state.

  19. Enhanced one-carbon flux towards DNA methylation: Effect of dietary methyl supplements against gamma-radiation-induced epigenetic modifications.

    PubMed

    Batra, Vipen; Sridhar, Swathi; Devasagayam, Thomas Paul Asir

    2010-02-12

    Radiation exposure poses a major risk for workers in the nuclear power plants and other radiation related industry. In this context, we demonstrate that gamma-radiation is an efficient DNA demethylating agent and its injurious effect can be minimized by dietary methyl supplements (folate, choline and vitamin B12). To elucidate the possible underlying mechanism(s), male Swiss mice were maintained on normal control diet (NCD) and methyl-supplemented diet (MSD). After 2 weeks of NCD and MSD dietary regimen, we exposed the animals to gamma-radiation (2, 4 and 6Gy) and investigated the profile of downstream metabolites and activity levels of one-carbon (C(1)) flux generating enzymes. In MSD fed and irradiated animals, hepatic folate levels increased (P<0.01), while hepatic homocysteine levels decreased (P<0.01) compared to NCD fed and irradiated animals. Although hepatic folate level increased significantly in MSD fed animals (P<0.01), it showed a decrease in response to high doses of gamma-irradiation. Under these conditions, a marked suppression of S-adenosylmethionine (SAM) levels occurred in NCD fed and irradiated animals, suggesting reduced conversion of homocysteine to SAM. Concomitant with decline in liver SAM Pool, activities of DNA methyltransferase (Dnmt, that methylates DNA) and methionine synthase (MSase, that regenerates methionine from homocysteine) were both decreased in NCD fed and irradiated mice. However, in MSD fed and irradiated mice, they were increased. These results strongly indicated that increased levels of dnmt and MSase may enhance C(1) flux towards DNA methylation reactions in MSD fed animals. These results were confirmed and further substantiated by measuring genomic DNA methylation levels, which were maintained at normal levels in MSD fed and irradiated mice compared to NCD fed and irradiated animals (P<0.01). In conclusion, our results suggest that maintenance of genomic DNA methylation under gamma-radiation stress might be a very dynamic

  20. Gamma radiation-induced grafting of glycidyl methacrylate (GMA) onto water hyacinth fibers

    NASA Astrophysics Data System (ADS)

    Madrid, Jordan F.; Nuesca, Guillermo M.; Abad, Lucille V.

    2013-04-01

    Water hyacinth fibers (Eichhornia crassipes) were functionalized using radiation-induced graft polymerization of glycidyl methacrylate by γ-rays from 60Co source. The simultaneous grafting technique was employed wherein the water hyacinth fibers were irradiated in nitrogen atmosphere in the presence of glycidyl methacrylate dissolved in water/methanol solvent. The effects of different grafting parameters to the grafting yield were evaluated. The optimal values of solvent, absorbed dose, dose rate, and concentration of monomer were found to be 1:3 (volume/volume) water-methanol solvent, 10 kGy, 8 kGy h-1 dose rate and 5% volume/volume glycidyl methacrylate, respectively. Using the optimum conditions, degree of grafting of approximately 58% was achieved. The grafted water hyacinth fibers were characterized using Attenuated Total Reflectance-Fourier Transformed Infrared Spectroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). The results of these tests confirmed the successful grafting of glycidyl methacrylate onto water hyacinth fibers.

  1. A cyanocobalamin dosimeter for monitoring gamma-radiation doses of 0.1-2 kGy

    NASA Astrophysics Data System (ADS)

    Maged, A. F.; Hamza, M. S. A.; Saad, E. A.

    1997-08-01

    A simple dosimeter is described for measuring gamma-ray doses useful for insect sterilization, seed-sprouting inhibition and food shelf-life extensions. The red aqueous solution of cyanocobalamin (B 12) before irradiation, assumes a stable yellow color when irradiated. It shows a linear response of absorbance decrease with the dose over the range of 0.1-2.0 kGy when the concentration of cyanocobalamin is equal 0.09 mM. The radiation-induced color is analyzed spectrophotometrically at the maximum absorption band (361 nm). The absorption spectra, dose response and post-irradiation stability of the dosimeter are discussed.

  2. Spectroscopic evaluation of painted layer structural changes induced by gamma radiation in experimental models

    NASA Astrophysics Data System (ADS)

    Manea, Mihaela M.; Moise, Ioan V.; Virgolici, Marian; Negut, Constantin D.; Barbu, Olimpia-Hinamatsuri; Cutrubinis, Mihalis; Fugaru, Viorel; Stanculescu, Ioana R.; Ponta, Corneliu C.

    2012-02-01

    The degradation of cultural heritage objects by insects and microorganisms is an important issue for conservators, art specialists and humankind in general. Gamma irradiation is an efficient method of polychrome wooden artifacts disinfestation. Color changes and other modifications in the physical chemical properties of materials induced by gamma irradiation are feared by cultural heritage responsible committees and they have to be evaluated objectively and precisely. In this paper FTIR and FT-Raman spectroscopy methods were used to investigate the structural changes in some experimental models of tempera paint layers on wood following 11 kGy gamma irradiation at two dose rates. Radiation chemistry depends on the particular pigment, matrix formed by protein, resin (in case of varnished samples) and water presence. For the majority of painted layer in experimental models very small spectral variations were observed. Small changes in the FTIR spectra were observed for the raw sienna experimental model: for the higher dose rate the egg yolk protein oxidation peaks and the CH stretching bands due to lipids degradation products increased.

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  4. A radiochromic folm dosimeter for gamma radiation in the absorbed-dose range 0.1-10 kGy

    NASA Astrophysics Data System (ADS)

    Khan, Hasan M.; Farahani, Mahnaz; William L., McLaughlin

    A commercially available leuco-dye film (FWT-63-02), having a thickness of 0.55 mm, has been investigated spectrophotometrically for its characteristics as a radiochromic dosimeter and for its potential use in food-irradiation applications. The γ-ray irradiation of the nearly colorless, transparent film induces blue color with an absorption maximum at 600 nm. The increase in absorbance at 600 nm per unit thickness of film (Δ A mm -1) is linear with dose in the dose range up to 8 kGy, with a slope of 0.91 mm -1·kGy -1. After a modest additional increase during the first day following irradiation, the radiation-induced color is stable when stored at room temperature at least for 5 weeks. The response slope is 16% higher when stored at 60°C, however, after the initial 1-day increase it is stable for several weeks when stored at that temperature. The response of the dosimeter is independent of dose rate in the range 0.5-170 Gy min -1.

  5. Ferulic acid inhibits gamma radiation-induced DNA strand breaks and enhances the survival of mice.

    PubMed

    Maurya, Dharmendra Kumar; Devasagayam, Thomas Paul Asir

    2013-02-01

    Ferulic acid (FA) is a monophenolic phenylpropanoid occurring in plant products such as rice bran, green tea, and coffee beans. It has been shown to have significant antioxidant effects in many studies. In the present study, we show that intraperitoneal administration of FA at a dose of 50 mg/kg body weight 1 hour prior to or immediately after whole-body γ-irradiation of mice with 4 Gy results in considerable reduction in the micronuclei formation in peripheral blood reticulocytes. Administration of the same amount of FA immediately after 4 Gy γ-irradiation showed significant decrease in the amount of DNA strand breaks in murine peripheral blood leukocytes and bone marrow cells as examined by comet assay. Further, immunostaining of mouse splenic lymphocytes for phspho-γH2AX was carried out, and it was observed that FA inhibits the γH2AX foci formation. Finally, the survival of mice upon 6, 8, and 10 Gy γ-ray exposure was monitored. FA enhances the survival of mice by a factor of 2.5 at a dose of 6 Gy γ-radiation but not at higher doses. In conclusion, FA has protective potential in both pre- and postirradiation exposure scenarios and enhances the survival of mice possibly by decreasing DNA damage as examined by γH2AX foci, micronuclei formation, and comet assay.

  6. [Malignant transformation of human fibroblasts by neutrons and by gamma radiation: Relationship to mutations induced

    SciTech Connect

    1993-12-31

    A brief overview if provided of selected reports presented at the International Symposium on Molecular Mechanisms of Radiation- and Chemical Carcinogen-Induced Cell Transformation held at Mackinac Island, Michigan on September 19-23, 1993.

  7. Pine polyphenols from Pinus koraiensis prevent injuries induced by gamma radiation in mice

    PubMed Central

    Li, Hui; Xu, Yier; Sun, Guicai

    2016-01-01

    Pine polyphenols (PPs) are bioactive dietary constituents that enhance health and help prevent diseases through antioxidants. Antioxidants reduce the level of oxidative damages caused by ionizing radiation (IR). The main purpose of this paper is to study the protective effect of PPs on peripheral blood, liver and spleen injuries in mice induced by IR. ICR (Institute of Cancer Research) male mice were administered orally with PPs (200 mg/kg b.wt.) once daily for 14 consecutive days prior to 7 Gy γ-radiations. PPs showed strong antioxidant activities. PPs significantly increased white blood cells, red blood cells and platelets counts. PPs also significantly reduced lipid peroxidation and increased the activities of superoxide dismutase, catalase and glutathione peroxidases, and the level of glutathione. PPs reduced the spleen morphologic injury. In addition, PPs inhibited mitochondria-dependent apoptosis pathways in splenocytes induced by IR. These results indicate that PPs are radioprotective promising reagents. PMID:27069807

  8. Pine polyphenols from Pinus koraiensis prevent injuries induced by gamma radiation in mice.

    PubMed

    Li, Hui; Wang, Zhenyu; Xu, Yier; Sun, Guicai

    2016-01-01

    Pine polyphenols (PPs) are bioactive dietary constituents that enhance health and help prevent diseases through antioxidants. Antioxidants reduce the level of oxidative damages caused by ionizing radiation (IR). The main purpose of this paper is to study the protective effect of PPs on peripheral blood, liver and spleen injuries in mice induced by IR. ICR (Institute of Cancer Research) male mice were administered orally with PPs (200 mg/kg b.wt.) once daily for 14 consecutive days prior to 7 Gy γ-radiations. PPs showed strong antioxidant activities. PPs significantly increased white blood cells, red blood cells and platelets counts. PPs also significantly reduced lipid peroxidation and increased the activities of superoxide dismutase, catalase and glutathione peroxidases, and the level of glutathione. PPs reduced the spleen morphologic injury. In addition, PPs inhibited mitochondria-dependent apoptosis pathways in splenocytes induced by IR. These results indicate that PPs are radioprotective promising reagents.

  9. Reversal of gamma-radiation-induced leukemogenesis in mice by immunomodulation with thiabendazole and dinitrofluorobenzene

    SciTech Connect

    Elgebaly, S.A.; Barton, R.; Forouhar, F.

    1985-04-01

    The effect of thiabendazole (TBZ) and dinitrofluorobenzene (DNFB) on radiation-induced leukemogenesis was investigated in the C57BL/6 mouse model. Administration of TBZ-DNFB during, post, or during and post irradiation successfully blocked leukemogenesis, as indicated by the absence of leukemia blast cells in thymus and peripheral blood, as well as prevented thymic lymphoma. TBZ-DNFB treatment prevented the development of leukemia when studies were terminated both after 7 months of last irradiation (disease fully developed) and after 5 months of last irradiation (disease in the process of development). This TBZ-DNFB treatment also resulted in a significant increase in survival.

  10. Oxidative stress and gamma radiation-induced cancellous bone loss with musculoskeletal disuse

    PubMed Central

    Kondo, Hisataka; Yumoto, Kenji; Alwood, Joshua S.; Mojarrab, Rose; Wang, Angela; Almeida, Eduardo A. C.; Searby, Nancy D.; Limoli, Charles L.

    2010-01-01

    Exposure of astronauts in space to radiation during weightlessness may contribute to subsequent bone loss. Gamma irradiation of postpubertal mice rapidly increases the number of bone-resorbing osteoclasts and causes bone loss in cancellous tissue; similar changes occur in skeletal diseases associated with oxidative stress. Therefore, we hypothesized that increased oxidative stress mediates radiation-induced bone loss and that musculoskeletal disuse changes the sensitivity of cancellous tissue to radiation exposure. Musculoskeletal disuse by hindlimb unloading (1 or 2 wk) or total body gamma irradiation (1 or 2 Gy of 137Cs) of 4-mo-old, male C57BL/6 mice each decreased cancellous bone volume fraction in the proximal tibiae and lumbar vertebrae. The extent of radiation-induced acute cancellous bone loss in tibiae and lumbar vertebrae was similar in normally loaded and hindlimb-unloaded mice. Similarly, osteoclast surface in the tibiae increased 46% as a result of irradiation, 47% as a result of hindlimb unloading, and 64% as a result of irradiation + hindlimb unloading compared with normally loaded mice. Irradiation, but not hindlimb unloading, reduced viability and increased apoptosis of marrow cells and caused oxidative damage to lipids within mineralized tissue. Irradiation also stimulated generation of reactive oxygen species in marrow cells. Furthermore, injection of α-lipoic acid, an antioxidant, mitigated the acute bone loss caused by irradiation. Together, these results showed that disuse and gamma irradiation, alone or in combination, caused a similar degree of acute cancellous bone loss and shared a common cellular mechanism of increased bone resorption. Furthermore, irradiation, but not disuse, may increase the number of osteoclasts and the extent of acute bone loss via increased reactive oxygen species production and ensuing oxidative damage, implying different molecular mechanisms. The finding that α-lipoic acid protected cancellous tissue from the

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

    NASA Astrophysics Data System (ADS)

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

    1997-05-01

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

  12. Gene expression profiling in MOLT-4 cells during gamma-radiation-induced apoptosis.

    PubMed

    Lindgren, Theres; Stigbrand, Torgny; Riklund, Katrine; Johansson, Lennart; Eriksson, David

    2012-06-01

    This study aims to identify the temporal changes in gene expression in MOLT-4, a leukemia cell line, in response to radiation and to present a comprehensive description of the pathways and processes that most significantly relate to the cellular biological responses. A global gene expression profile of 24,500 genes was performed on MOLT-4 tumor cells following exposure to 5 Gy of ionizing radiation ((60)Co) using a bead chip array (Illumina). Signaling pathways and processes significantly altered following irradiation were explored using MetaCore. Cellular viability [3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], activation of cell cycle checkpoints [fluorescence activated cell sorting (FACS)], and induction of apoptosis (FACS, caspase assays) were evaluated to correlate these biological responses to the gene expression changes. Totally, 698 different genes displayed a significantly altered expression following radiation, and out of these transcripts, all but one showed increased expression. One hour following irradiation, the expression was changed only for a few genes. Striking changes appeared at later time-points. From 3 to 24 h post-irradiation, a significant fraction of the genes with altered expression were found to be involved in cell cycle checkpoints and their regulation (CDKN1A), DNA repair (GADD45A, DDB2, XPC), apoptosis induction (DR5, FasR, Apo-2L, Bax), and T-cell activation/proliferation (CD70, OX40L). Irradiated MOLT-4 cells were arrested at the G2-checkpoint, followed by a decrease in cell viability, most pronounced 48 h after exposure. The cell death was executed by induced apoptosis and was visualized by an increase in subG1 cells and an increased activation of initiator (caspase-8 and caspase-9) and execution (caspase-3) caspases. Activation of cell cycle arrest and apoptosis correlated well in time with the changes in gene expression of those genes important for these biological processes. Activation of the apoptotic signaling

  13. Suppressed expression of non-DSB repair genes inhibits gamma-radiation-induced cytogenetic repair and cell cycle arrest.

    PubMed

    Zhang, Ye; Rohde, Larry H; Emami, Kamal; Hammond, Dianne; Casey, Rachael; Mehta, Satish K; Jeevarajan, Antony S; Pierson, Duane L; Wu, Honglu

    2008-11-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in double-strand break (DSB) repair, and its impact on cytogenetic responses has not been well studied. The purpose of this study is to identify new roles of IR inducible genes in regulating DSB repair and cell cycle progression. In this study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by small interfering RNA in human fibroblast cells. Frequency of micronuclei (MN) formation and chromosome aberrations were measured to determine efficiency of cytogenetic repair, especially DSB repair. In response to IR, the formation of MN was significantly increased by suppressed expression of five genes: Ku70 (DSB repair pathway), XPA (nucleotide excision repair pathway), RPA1 (mismatch repair pathway), RAD17 and RBBP8 (cell cycle control). Knocked-down expression of four genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Moreover, decreased XPA, p21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Nine of these eleven genes, whose knock-down expression affected cytogenetic repair, were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate IR-induced biological consequences. Furthermore, eight non-DBS repair genes showed involvement in regulating DSB repair, indicating that

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

    SciTech Connect

    Zabanov, S.A.; Vasil`eva, L.A.; Ratner, V.A. |

    1995-06-01

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

  15. Sensitivity of the green algae Chlamydomonas reinhardtii to gamma radiation: Photosynthetic performance and ROS formation.

    PubMed

    Gomes, Tânia; Xie, Li; Brede, Dag; Lind, Ole-Christian; Solhaug, Knut Asbjørn; Salbu, Brit; Tollefsen, Knut Erik

    2017-02-01

    The aquatic environment is continuously exposed to ionizing radiation from both natural and anthropogenic sources, making the characterization of ecological and health risks associated with radiation of large importance. Microalgae represent the main source of biomass production in the aquatic ecosystem, thus becoming a highly relevant biological model to assess the impacts of gamma radiation. However, little information is available on the effects of gamma radiation on microalgal species, making environmental radioprotection of this group of species challenging. In this context, the present study aimed to improve the understanding of the effects and toxic mechanisms of gamma radiation in the unicellular green algae Chlamydomonas reinhardtii focusing on the activity of the photosynthetic apparatus and ROS formation. Algal cells were exposed to gamma radiation (0.49-1677mGy/h) for 6h and chlorophyll fluorescence parameters obtained by PAM fluorometry, while two fluorescent probes carboxy-H2DFFDA and DHR 123 were used for the quantification of ROS. The alterations seen in functional parameters of C. reinhardtii PSII after 6h of exposure to gamma radiation showed modifications of PSII energy transfer associated with electron transport and energy dissipation pathways, especially at the higher dose rates used. Results also showed that gamma radiation induced ROS in a dose-dependent manner under both light and dark conditions. The observed decrease in photosynthetic efficiency seems to be connected to the formation of ROS and can potentially lead to oxidative stress and cellular damage in chloroplasts. To our knowledge, this is the first report on changes in several chlorophyll fluorescence parameters associated with photosynthetic performance and ROS formation in microalgae after exposure to gamma radiation.

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

    SciTech Connect

    Marsh, S.F.

    1991-01-01

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

  17. Amifostine ameliorates recognition memory defect in acute radiation syndrome caused by relatively low-dose of gamma radiation.

    PubMed

    Lee, Hae-June; Kim, Joong-Sun; Song, Myoung-Sub; Seo, Heung-Sik; Yang, Miyoung; Kim, Jong Choon; Jo, Sung-Kee; Shin, Taekyun; Moon, Changjong; Kim, Sung-Ho

    2010-03-01

    This study examined whether amifostine (WR-2721) could attenuate memory impairment and suppress hippocampal neurogenesis in adult mice with the relatively low-dose exposure of acute radiation syndrome (ARS). These were assessed using object recognition memory test, the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay, and immunohistochemical markers of neurogenesis [Ki-67 and doublecortin (DCX)]. Amifostine treatment (214 mg/kg, i.p.) prior to irradiation significantly attenuated the recognition memory defect in ARS, and markedly blocked the apoptotic death and decrease of Ki-67- and DCX-positive cells in ARS. Therefore, amifostine may attenuate recognition memory defect in a relatively low-dose exposure of ARS in adult mice, possibly by inhibiting a detrimental effect of irradiation on hippocampal neurogenesis.

  18. Gamma radiation effects in amorphous silicon and silicon nitride photonic devices.

    PubMed

    Du, Qingyang; Huang, Yizhong; Ogbuu, Okechukwu; Zhang, Wei; Li, Junying; Singh, Vivek; Agarwal, Anuradha M; Hu, Juejun

    2017-02-01

    Understanding radiation damage is of significant importance for devices operating in radiation-harsh environments. In this Letter, we present a systematic study on gamma radiation effects in amorphous silicon and silicon nitride guided wave devices. It is found that gamma radiation increases the waveguide modal effective indices by as much as 4×10-3 in amorphous silicon and 5×10-4 in silicon nitride at 10 Mrad dose. This Letter further reveals that surface oxidation and radiation-induced densification account for the observed index change.

  19. Low Dose Gamma Radiation Monitoring Through TiO{sub 2} Doped Lead Phthalocyanine (Pb-Pc) Based Schottky Device

    SciTech Connect

    Janu, Yojana; Gautam, Anil; Kumar, Manish; Prasad, Narottam; Deol, Y. S.; Roy, M. S.

    2008-04-23

    The concept of Organic thin film based solid-state dosimeters is relatively new and more effective. The organic conductor based solid-state dosimeter provides a mean for low cost, ease to fabricate and sensitive radiation sensor which can be employed as pocket dosimeter for army personals getting exposed to nuclear radiation while working in the radioactive environment This concept is being utilized here for monitoring the effect of nuclear radiation on our organic material based sandwiched devices. In the present communication, lead Phthalocyanine (PbPc) doped with TiO{sub 2} (5% by weight) is developed into the form of thin film structure. The developed ITO/PbPc: TiO{sub 2}/Ag Schottky device structure was characterized in terms of change in its electrical and optical properties before and after exposure to radiation Exposure to radiation imparts an accelerated decrease in forward bias current and capacitance characteristics reveal a linear relationship between dose v/s current behavior which supports its suitability as pocket dosimeter for the dose ranging from 50 mR to 800 mR.

  20. Defective expression of Notch1 and Notch2 in connection to alterations of c-Myc and Ikaros in gamma-radiation-induced mouse thymic lymphomas.

    PubMed

    López-Nieva, P; Santos, J; Fernández-Piqueras, J

    2004-07-01

    Gamma-radiation-induced thymic lymphomas constitute a heterogeneous group of T-cell lymphomas. Some tumour suppressor genes and oncogenes have been shown to be defective in a fraction of such lymphomas, yet a considerable number of these remain elusive in terms of gene alterations. In the present work we present evidence that gamma-radiation-induced thymic lymphomas in (C57BL/6 J x BALB/c) F1 hybrid mice often exhibit increased levels of Notch1 expression, but, contrary to what was expected, they also exhibit a clearly reduced Notch2 mRNA expression, suggesting a cooperative antagonism of these genes. These results represent the first reported instance for the involvement of Notch2 inactivation in the development of thymic primary tumours while confirming the role of Notch1 as an activated oncogene. Additional analyses revealed that c-Myc over-expression and partial inactivation of Znfn1a1/Ikaros appear to be relevant events some how coupled to alterations in Notch genes inducing these kinds of tumours.

  1. Evaluation of genotoxicity of the acute gamma radiation on earthworm Eisenia fetida using single cell gel electrophoresis technique (Comet assay).

    PubMed

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

    2015-12-01

    Earthworms (Eisenia fetida) most suitable biological indicators of radioactive pollution. Radiation-induced lesions in DNA can be considered to be molecular markers for early effects of ionizing radiation. Gamma radiation produces a wide spectrum of DNA. Some of these lesions, i.e., DNA strand breaks and alkali labile sites can be detected by the single-cell gel electrophoresis (SCGE) or comet assay by measuring the migration of DNA from immobilized nuclear DNA. E. fetida were exposed to different doses of gamma radiation, i.e., 1, 5, 10, 20, 30, 40 and 50Gy, and comet assay was performed for all the doses along with control at 1, 3 and 5h post irradiation to evaluate the genotoxicity of gamma radiation in this organism. The DNA damage was measured as percentage of comet tail DNA. A significant increase in DNA damage was observed in samples exposed to 5Gy and above, and the increase in DNA damage was dose dependent i.e., DNA damage was increased with increased doses of radiation. The highest DNA damage was noticed at 1h post irradiation and gradually decreased with time, i.e., at 3 and 5h post irradiation. The present study reveals that gamma radiation induces DNA damage in E. fetida and the comet assay is a sensitive and rapid method for its detection to detect genotoxicity of gamma radiation.

  2. An integrated view of gamma radiation effects on marine fauna: from molecules to ecosystems.

    PubMed

    Won, Eun-Ji; Dahms, Hans-U; Kumar, K Suresh; Shin, Kyung-Hoon; Lee, Jae-Seong

    2015-11-01

    Accidental release of nuclides into the ocean is causing health risks to marine organisms and humans. All life forms are susceptible to gamma radiation with a high variation, depending on various physical factors such as dose, mode, and time of exposure and various biological factors such as species, vitality, age, and gender. Differences in sensitivity of gamma radiation are also associated with different efficiencies of mechanisms related to protection and repair systems. Gamma radiation may also affect various other integration levels: from gene, protein, cells and organs, population, and communities, disturbing the energy flow of food webs that will ultimately affect the structure and functioning of ecosystems. Depending on exposure levels, gamma radiation induces damages on growth and reproduction in various organisms such as zooplankton, benthos, and fish in aquatic ecosystems. In this paper, harmful effects of gamma-irradiated aquatic organisms are described and the potential of marine copepods in assessing the risk of gamma radiation is discussed with respect to physiological adverse effects that even affect the ecosystem level.

  3. Determination of the Absorption Coefficient and Cloudiness Multiplicity Attenuation During the Gamma-Radiation Passage

    NASA Astrophysics Data System (ADS)

    Orlova, K. N.; Borovikov, I. F.; Gaidamak, M. A.

    2016-08-01

    The paper presents background value equivalent dose of gamma-radiation investigation in different weather: clear cloudy and overcast. The change of the dose rate of gamma radiation, depending on the weather and the ability cloudiness to shield gamma rays is shown. A new method for eliminating the consequences of accidents at nuclear power plants or plants using radioactive elements is proposed. A calculation method of cloudiness coefficient absorption and cloudiness gamma-radiation multiplicity attenuation is developed. The gamma- radiation multiplicity attenuation and the absorption coefficient of gamma radiation were calculated.

  4. Gamma-radiation-induced ATM-dependent signalling in human T-lymphocyte leukemic cells, MOLT-4.

    PubMed

    Tichý, Ales; Záskodová, Darina; Rezácová, Martina; Vávrová, Jirina; Vokurková, Doris; Pejchal, Jaroslav; Vilasová, Zdena; Cerman, Jaroslav; Osterreicher, Jan

    2007-01-01

    ATM kinase (ATM) is essential for activation of cell cycle check points and DNA repair in response to ionizing radiation (IR). In this work we studied the molecular mechanisms regulating DNA repair and cell death in human T-lymphocyte leukemic cells, MOLT-4. Apoptosis was evaluated by flow-cytometric detection of annexin V. Early apoptotic cells were determined as sub-G1 cells and late apoptotic cells were determined as APO2.7-positive ones. Proteins involved in ATM signalling pathway were analysed by Western-blotting. We observed a rapid (0.5 h) phosphorylation of ATM declining after 6 h after irradiation by all the doses studied (1.5, 3.0, and 7.5 Gy). Checkpoint kinase-2 (Chk-2) was also phosphorylated after 0.5 h but its phosphorylated form persisted 4, 2, and 1 h after the doses of 1.5, 3.0, and 7.5 Gy, respectively. The amount of p53 protein and its form phosphorylated on Ser-392 increased 1 h after irradiation (1-10 Gy). The lethal dose of 7.5 Gy caused an immediate induction and phosphorylation of p53 after 0.5 h post-irradiation. At the time of phosphorylation of p53, we found simultaneous phosphorylation of the oncoprotein Mdm2 on Ser-166. Neither ATM nor its downstream targets showed a dose-dependent response after 1 h when irradiated by the doses of 1-10 Gy. MOLT-4 cells were very sensitive to the effect of IR. Even low doses, such as 1.5 Gy, induced apoptosis 16 h after irradiation (evaluated according to the cleavage of nuclear lamin B to a 48-kDa fragment). IR-induced molecular signalling after exposure to all the tested doses was triggered by rapid phosphorylation of ATM and Chk-2. Subsequent induction of p53 protein and its phosphorylation was accompanied by concomitant phosphorylation of its negative regulator, oncoprotein Mdm2, and followed by induction of apoptosis.

  5. Diffuse gamma radiation

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  6. Inhaled /sup 147/Pm and/or total-body gamma radiation: Early mortality and morbidity in rats

    SciTech Connect

    Filipy, R.E.; Lauhala, K.E.; McGee, D.R.; Cannon, W.C.; Buschbom, R.L.; Decker, J.R.; Kuffel, E.G.; Park, J.F.; Ragan, H.A.; Yaniv, S.S.; Scott, B.R.

    1989-05-01

    Rats were given doses of /sup 60/Co gamma radiation and/or lung burdens of /sup 147/Pm (in fused aluminosilicate particles) within lethal ranges in an experiment to determine and compare morbidity and mortality responses for the radiation insults within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Acute mortality and morbidity from inhaled promethium were caused primarily by radiation pneumonitis and pulmonary fibrosis that occurred more than 53 days after exposure. Acute mortality and morbidity from total-body gamma irradiation occurred within 30 days of exposure and resulted from the bone-marrow radiation syndrome. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell levels and by reduced body weight gain in animals that survived the acute gamma radiation syndrome. Inhaled promethium caused a loss of body weight and diminished pulmonary function, but its only effect on blood cell levels was lymphocytopenia. Combined gamma irradiation and promethium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Promethium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the later effect of promethium lung burdens. 70 refs., 68 figs., 21 tabs.

  7. Analysis of drought-tolerant sugar beet (Beta vulgaris L.) mutants induced with gamma radiation using SDS-PAGE and ISSR markers.

    PubMed

    Sen, Ayse; Alikamanoglu, Sema

    2012-01-01

    Drought is one of the major environmental stresses which greatly affect the plant growth and productivity. In the present study, various doses (0-75Gy) of gamma rays were applied to investigate the effect of radiation on shoot tip explants. It was observed that the regeneration rates and plant fresh weights decreased significantly with an increase in radiation dose. The optimal irradiation doses for mutation induction were determined at 15 and 20Gy. Afterwards, the induction of somatic mutation in sugar beet (Beta vulgaris L.) was investigated by irradiation of shoot tips with 15 and 20Gy gamma rays. Irradiated shoot tips were sub-cultured and M(1)V(1)-M(1)V(3) generations were obtained. Mutants tolerant to drought stress were selected on MS medium, supplemented with 10 and 20gl(-1) PEG6000. Of the M(1)V(3) plantlets, drought-tolerant mutants were selected. Leaf soluble proteins obtained from the control and drought-tolerant mutants were analyzed by SDS-PAGE. A total of 22 protein bands were determined and 2 of them were observed to be drought-tolerant mutants except the control. Polymorphism was also detected among the control and drought-tolerant mutants by DNA fingerprinting using ISSR markers. A total of 106 PCR fragments were amplified with 19 ISSR primers and 91 of them were polymorphic. The dendrograms were separated into two main clusters. First cluster included M8 mutant plant, which was applied 20Gy gamma radiation and regenerated on selective culture media containing 10gl(-1) PEG6000 concentration, and the second cluster was further divided into five sub-clusters.

  8. Effects of Xylopia aethiopica (Annonaceae) fruit methanol extract on gamma-radiation-induced oxidative stress in brain of adult male Wistar rats.

    PubMed

    Adaramoye, O A; Popoola, Bosede O; Farombi, E O

    2010-09-01

    Xylopia aethiopica (XA) (Annonaceae) possesses great nutritional and medicinal values. This study was designed to investigate the effects of XA fruit methanol extract on oxidative stress in brain of rats exposed to whole body gamma-radiation (5 Gy). Vitamin C (VC) served as standard antioxidant. Forty-four rats were divided into 4 groups of 11 rats each. One group served as control, two different groups were treated with XA and VC (250 mg/kg), 6 weeks before and 8 weeks after irradiation, and fourth group was only irradiated. Rats were sacrificed 1 and 8 weeks after irradiation. The antioxidant status, viz. Lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione-s-transferase (GST) and glutathione (GSH) were estimated. Results indicate a significant increase (p < 0.05) in levels of brain LPO after irradiation. LPO increased by 90% and 151%, after 1 and 8 weeks of irradiation, respectively. Irradiation caused significant (p < 0.05) decreases in levels of GSH and GST by 61% and 43% after 1 week and, 75% and 73%, respectively, after 8 weeks of exposure. CAT and SOD levels were decreased by 62% and 68%, respectively, after 8 weeks of irradiation. Treatment with XA and VC ameliorated the radiation-induced decreases in antioxidant status of the animals. These suggest that XA could have beneficial effect by inhibiting oxidative damage in brain of exposed rats.

  9. Repair of DNA double-strand breaks is not modulated by low-dose gamma radiation in C57BL/6J mice.

    PubMed

    Blimkie, Melinda S J; Fung, Luke C W; Petoukhov, Eugenia S; Girard, Cyrielle; Klokov, Dmitry

    2014-05-01

    In this study, we sought to determine whether low-dose ionizing radiation, previously shown to induce a systemic adaptive response in C57BL/6J mice, is capable of enhancing the rate of DNA double-strand break repair. Repair capacity was determined by measuring γ-H2AX levels in splenic and thymic lymphocytes, using flow cytometry, at different times after a challenge irradiation (2 Gy, (60)Co). Irradiation with low doses (20 and 100 mGy) was conducted in vivo, whereas the challenge dose was applied to primary cultures of splenocytes and thymocytes in vitro 24 h later. Obtained kinetics curves of formation and loss of γ-H2AX indicated that cells from low-dose irradiated mice did not express more efficient DNA double-strand break repair compared to controls. Immunoblot analysis of γ-H2AX and Phospho-Ser-1981 ATM confirmed that DNA damage signaling was not modulated by preliminary low-dose radiation. Mouse embryonic fibroblasts of C57BL genetic background failed to show clonogenic survival radioadaptive response or enhanced repair of DNA double-strand breaks as evaluated by immunofluorescence microscopy of γ-H2AX foci. Our results indicate that radiation adaptive responses at systemic levels, such as increases in the tumor latency times in aging mice, may not be mediated by modulated DNA repair, and that the genetic background may affect expression of a radioadaptive response.

  10. Measuring DNA Damage and Repair in Mouse Splenocytes After Chronic In Vivo Exposure to Very Low Doses of Beta- and Gamma-Radiation.

    PubMed

    Flegal, Matthew; Blimkie, Melinda S; Wyatt, Heather; Bugden, Michelle; Surette, Joel; Klokov, Dmitry

    2015-07-03

    Low dose radiation exposure may produce a variety of biological effects that are different in quantity and quality from the effects produced by high radiation doses. Addressing questions related to environmental, occupational and public health safety in a proper and scientifically justified manner heavily relies on the ability to accurately measure the biological effects of low dose pollutants, such as ionizing radiation and chemical substances. DNA damage and repair are the most important early indicators of health risks due to their potential long term consequences, such as cancer. Here we describe a protocol to study the effect of chronic in vivo exposure to low doses of γ- and β-radiation on DNA damage and repair in mouse spleen cells. Using a commonly accepted marker of DNA double-strand breaks, phosphorylated histone H2AX called γH2AX, we demonstrate how it can be used to evaluate not only the levels of DNA damage, but also changes in the DNA repair capacity potentially produced by low dose in vivo exposures. Flow cytometry allows fast, accurate and reliable measurement of immunofluorescently labeled γH2AX in a large number of samples. DNA double-strand break repair can be evaluated by exposing extracted splenocytes to a challenging dose of 2 Gy to produce a sufficient number of DNA breaks to trigger repair and by measuring the induced (1 hr post-irradiation) and residual DNA damage (24 hrs post-irradiation). Residual DNA damage would be indicative of incomplete repair and the risk of long-term genomic instability and cancer. Combined with other assays and end-points that can easily be measured in such in vivo studies (e.g., chromosomal aberrations, micronuclei frequencies in bone marrow reticulocytes, gene expression, etc.), this approach allows an accurate and contextual evaluation of the biological effects of low level stressors.

  11. [Effect of continuous gamma-radiation at low doses on clonogenic hemopoietic (CFU-S) and stromal (CFU-F) bone marrow cells ].

    PubMed

    Domaratskaia, E I; Starostin, V I; Tsetlin, V V; Butorina, N N; Bueverova, E I; Bragina, E V; Khrushchov, N G

    2002-01-01

    We studied the effects of low doses of continuous gamma-irradiation (Co60, 10 days, mean daily dose power 1.5-2.0 mGy, total dose 15 mGy) on hemopoietic and stromal progenitor cells of murine bone marrow. The content of hemopoietic clonogenic cells representing a "younger" (CFU-S-11) and more "mature" (CFU-S-7) categories in the compartment of stem cells was determined in the bone marrow. The state of bone marrow stroma was estimated by the method of in vitro cloning according to the number of progenitor cells that form colonies of fibroblasts (CFU-F) and by the method of ectopic transplantation according to the capacity of stroma of organizing and building new hemopoietic territories. Continuous gamma-irradiation at low doses, that were by one order of magnitude lower than those inducing hermesis, exerted a stimulating effect on both hemopoietic (CFU-S) and stromal (CFU-F) progenitor cells. The number of CFU-S in the compartment of stem cells of the bone marrow markedly increased and they formed larger hemopoietic territories but these cells appeared to create a qualitatively different microenvironment, which stimulated the proliferation of CFU-S.

  12. Galactic plane gamma-radiation

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    Analysis of the SAS 2 data together with the COS B results shows that the distribution of galactic gamma-radiation has several similarities to that of other large-scale tracers of galactic structure. The radiation is primarily confined to a thin disc which exhibits offsets from b = 0 degrees similar to warping at radio frequencies. The principal distinction of the gamma-radiation is a stronger contrast in intensity between the region from 310 to 45 degrees in longitude and the regions away from the center that can be attributed to a variation in cosmic-ray density as a function of position in Galaxy. The diffuse galactic gamma-ray energy spectrum shows no significant variation in direction, and the spectrum seen along the plane is the same as that for the galactic component of the gamma-radiation at high altitudes. The uniformity of the galactic gamma-ray spectrum, the smooth decrease in intensity as a function of altitude, and the absence of any galactic gamma-ray sources at high altitudes indicate a diffuse origin for bulk of the galactic gamma-radiation rather than a collection of localized sources.

  13. Cytokine profile of conditioned medium from human tumor cell lines after acute and fractionated doses of gamma radiation and its effect on survival of bystander tumor cells.

    PubMed

    Desai, Sejal; Kumar, Amit; Laskar, S; Pandey, B N

    2013-01-01

    Cytokines are known to play pivotal roles in cancer initiation, progression and pathogenesis. Accumulating evidences suggest differences in basal and stress-induced cytokine profiles of cancers with diverse origin. However, a comprehensive investigation characterising the cytokine profile of various tumor types after acute and fractionated doses of gamma-irradiation, and its effect on survival of bystander cells is not well known in literature. In the present study, we have evaluated the cytokine secretion profile of human tumor cell lines (HT1080, U373MG, HT29, A549 and MCF-7) either before (basal) or after acute (2, 6 Gy) and fractionated doses (3×2 Gy) of gamma-irradiation in culture medium obtained from these cells by multiplex bead array/ELISA. Moreover, clonogenic assays were performed to evaluate the effect of conditioned medium (CM) on the survival and growth of respective cells. Based on the screening of 28 analytes, our results showed that the basal profiles of these cell lines varied considerably in terms of the number and magnitude of secreted factors, which was minimum in MCF-7. Interestingly, TNF-α, IL-1β, PDGF-AA, TGF-β1, fractalkine, IL-8, VEGF and GCSF were found in CM of all the cell lines. However, secretion of certain cytokines was cell line-specific. Moreover, CM caused increase in clonogenic survival of respective tumor cells (in the order HT1080>U373MG>HT29>A549>MCF-7), which was correlated with the levels of IL-1β, IL-6, IL-8, GMCSF and VEGF in their CM. After irradiation, the levels of most of the cytokines increased markedly in a dose dependent manner. The fold change in cytokine levels was lower in irradiated conditioned medium (ICM) of tumor cells collected after fractionated than respective acute dose, except in MCF-7. Interestingly, amongst these cell lines, the radiation-induced fold increase in cytokine levels was maximum in ICM of A549 cells. Moreover, bystander A549 cells treated with respective ICM showed dose dependent

  14. Semiquinone glucoside derivative (SQGD) isolated from Bacillus sp. INM-1 protects against gamma radiation-induced oxidative stress.

    PubMed

    Mishra, Saurabh; Malhotra, Poonam; Gupta, Ashutosh K; Singh, Praveen K; Javed, Saleem; Kumar, Raj

    2014-03-01

    In the present study, radioprotective potential of Semiquinone glucoside derivative (SQGD) isolated from radioresistant bacterium Bacillus sp. INM-1 was evaluated. γ-Radiation induced protein carbonylation, plasmid DNA damage, enzyme functional impairment, lipid peroxidation, HO radicals generation and their protection by SQGD was assessed. As a result of SQGD treatment, significant inhibition (p<0.05) in protein carbonylation was observed with BSA. SQGD treatment was found to restore supercoiled (~70±3.21%) form of irradiated plasmid DNA against γ-irradiation. SQGD protects enzymes (EcoR1 and BamH1) against radiation-induced dysfunctioning. SQGD significantly inhibited (p<0.05) lipid peroxidation in liposomes, brain and liver homogenate. Higher HO(•) radicals-averting activity of SQGD was observed in the serum and liver homogenate of C57BL/6 mice against H2O2-induced oxidative stress. In conclusion, SQGD demonstrates excellent radical-scavenging activity towards bio-macromolecules in irradiated environment and can be developed as an ideal radioprotector against radiation-induced oxidative stress in future.

  15. Effects of an acute dose of gamma radiation exposure on stem diameter growth, carbon gain, and biomass partitioning in Helianthus annuus

    SciTech Connect

    Thiede, M.E.

    1988-05-25

    Nineteen-day-old dwarf sunflower plants (Helianthus annuus, variety NK894) received a variable dose (0-40 Gy) from a cobalt-60 gamma source. A very sensitive stem monitoring device, developed at Battelle's Pacific Northwest Laboratories, Richland, Washington was used to measure real-time changes in stem diameter. Exposure of plants caused a significant reduction in stem growth and root biomass. Doses as low as 5 Gy resulted in a significant increase in leaf density, suggesting that nonreversible morphological growth changes could be induced by very low doses of radiation. Carbohydrate analysis of 40-Gy irradiated plants demonstrated significantly more starch content in leaves and significantly less starch content in stems 18 days after exposure than did control plants. In contrast, the carbohydrate content in roots of 40-Gy irradiated plants were not significantly different from unirradiated plants 18 days after exposure. These results indicate that radiation either decreased phloem transport or reduced the availability of sugar reducing enzymes in irradiated plants. 44 refs., 12 figs.

  16. Gamma-Radiation-Induced Degradation of Actively Pumped Single-Mode Ytterbium-Doped Optical Laser - Postprint

    DTIC Science & Technology

    2015-01-01

    discussed. Keywords: Radiation effects, radiation-induced absorption, gamma irradiation, rare- earth doped fibers, rare- earth doped fiber amplifiers...passive optical fibers have identified that the major mechanism of performance degradation is the creation of absorbing species in the fiber, which in...turn inhibit the transmission of light at certain wavelengths1,2,3,4. In recent years, the use of rare- earth (RE) doped optical fibers has expanded

  17. Gamma Radiation Tolerance of Magnetic Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Ren, Fanghui; Jander, Albrecht; Dhagat, Pallavi; Nordman, Cathy

    2011-10-01

    Determining the radiation tolerance of magnetic tunnel junctions (MTJ), which are the storage elements of non-volatile magnetoresistive random access memories (MRAM), is important for investigating their potential application in space. In this effort, the effect of gamma radiation on MTJs with MgO tunnel barriers was studied. Experimental and control groups of samples were characterized by ex situ measurements of the magnetoresistive hysteresis loops and I-V curves. The experimental group was exposed to gamma rays from a ^60Co source. The samples initially received a dose of 5.9 Mrad (Si) after which they were again characterized electrically and magnetically. Irradiation was then continued for a cumulative dose of 10 Mrad and the devices re-measured. The result shows no change in magnetic properties such as coercivity or exchange coupling due to irradiation. After correcting for differences in temperature at the time of testing, the tunneling magnetoresistance was also found to be unchanged. Thus, it has been determined that MgO-based MTJs are highly tolerant of gamma radiation, particularly in comparison to silicon field-effect transistors which have been shown to degrade with gamma ray exposure even as low as 100 Krad [Zhiyuan Hu. et al., IEEE trans. on Nucl. Sci., vol. 58, 2011].

  18. Effect of gamma radiation on honey quality control

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  19. Alterations in the hematological profile in rat following whole body gamma radiation with and without venoruton pretreatment

    SciTech Connect

    Kanwar, K.C.; Verma, A.

    1992-07-01

    The radioprotective effect of venoruton [O-({beta}-hydroxyethyl)-rutoside] has been assessed in the hematological profile of Swiss albino male rats subjected to a single dose of 300 rads whole body gamma radiation. The results showed that the severity of the radiation-induced abnormalities in the red and white blood cells is significantly lessened by venoruton administered prior to radiation exposure. 34 refs., 2 tabs.

  20. Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicity.

    PubMed

    Madureira, Joana; Pimenta, Andreia I; Popescu, Larisa; Besleaga, Alexandra; Dias, Maria Inês; Santos, Pedro M P; Melo, Rita; Ferreira, Isabel C F R; Cabo Verde, Sandra; Margaça, Fernanda M A

    2017-02-01

    A comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters.

  1. Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation

    SciTech Connect

    Wyrobek, A. J.; Manohar, C. F.; Nelson, D. O.; Furtado, M. R.; Bhattacharya, M. S.; Marchetti, F.; Coleman, M.A.

    2011-04-18

    We investigated the low dose dependency of the transcriptional response of human cells to characterize the shape and biological functions associated with the dose response curve and to identify common and conserved functions of low dose expressed genes across cells and tissues. Human lymphoblastoid (HL) cells from two unrelated individuals were exposed to graded doses of radiation spanning the range of 1-10 cGy were analyzed by transcriptome profiling, qPCR and bioinformatics, in comparison to sham irradiated samples. A set of {approx}80 genes showed consistent responses in both cell lines; these genes were associated with homeostasis mechanisms (e.g., membrane signaling, molecule transport), subcellular locations (e.g., Golgi, and endoplasmic reticulum), and involved diverse signal transduction pathways. The majority of radiation-modulated genes had plateau-like responses across 1-10 cGy, some with suggestive evidence that transcription was modulated at doses below 1 cGy. MYC, FOS and TP53 were the major network nodes of the low-dose response in HL cells. Comparison our low dose expression findings in HL cells with those of prior studies in mouse brain after whole body exposure, in human keratinocyte cultures, and in endothelial cells cultures, indicates that certain components of the low dose radiation response are broadly conserved across cell types and tissues, independent of proliferation status.

  2. Bioburden assessment and gamma radiation inactivation patterns in parchment documents

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  3. Inhaled /sup 239/PuO/sub 2/ and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

    SciTech Connect

    Filipy, R.E.; Decker, J.R.; Lai, Y.L.; Lauhala, K.E.; Buschbom, R.L.; Hiastala, M.P.; McGee, D.R.; Park, J.F.; Kuffel, E.G.; Ragan, H.A.; Cannon, W.C.; Yaniv, S.S.; Scott, B.R.

    1988-08-01

    Rats and beagle dogs were given doses of /sup 60/Co gamma radiation and/or body burdens of /sup 239/PuO/sub 2/ within lethal ranges in an experiment to determine and compare morbidity and mortality responses of both species within 1 year after exposure. Radiation-induced morbidity was assessed by measuring changes in body weights, hematologic parameters, and pulmonary-function parameters. Gamma radiation caused transient morbidity, reflected by immediately depressed blood cell concentrations and by long-term loss of body weight and diminished pulmonary function in animals of both species that survived the acute gamma radiation syndrome. Inhaled plutonium caused a loss of body weight and diminished pulmonary function in both species, but its only effect on blood cell concentrations was lymphocytopenia in dogs. Combined gamma irradiation and plutonium lung burdens were synergistic, in that animals receiving both radiation insults had higher morbidity and mortality rates than would be predicted based on the effect of either kind of radiation alone. Plutonium lung burdens enhanced the effect of gamma radiation in rats within the first 30 days of exposure, and gamma radiation enhanced the long-term effect of plutonium lung burdens in both species. Rats were less sensitive to both kinds of radiation, whether administered alone or in combination. 71 refs., 105 figs., 48 tabs.

  4. The effects of integrated treatment of UV light and low dose gamma radiation on Escherichia coli O157:H7 and Salmonella enterica on grape tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In recent years considerable numbers of foodborne disease outbreaks associated with produce were reported and specifically Tomatoes have been involved with a number of multi state outbreaks. The purpose of this study was to evaluate efficacy of integrated treatment of UVC and low dose Gamma radiatio...

  5. Assessment of background gamma radiation levels using airborne gamma ray spectrometer data over uranium deposits, Cuddapah Basin, India - A comparative study of dose rates estimated by AGRS and PGRS.

    PubMed

    Srinivas, D; Ramesh Babu, V; Patra, I; Tripathi, Shailesh; Ramayya, M S; Chaturvedi, A K

    2017-02-01

    areas to assess any changes in gamma radiation levels due to mining and milling activities in future.

  6. Key comparison BIPM.RI(I)-K4 of the absorbed dose to water standards of the PTB, Germany and the BIPM in 60Co gamma radiation

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Burns, D. T.; Kapsch, R.-P.; Krauss, A.

    2016-01-01

    An indirect comparison has been made of the standards for absorbed dose to water in 60Co radiation of the Physikalisch-Technische Bundesanstalt, (PTB), Germany and of the Bureau International des Poids et Mesures (BIPM). The measurements at the BIPM were carried out in October 2015. The comparison result, based on the calibration coefficients for two transfer standards and evaluated as a ratio of the PTB and the BIPM standards for absorbed dose to water, is 0.9977 with a combined standard uncertainty of 3.8 × 10-3. The results are analysed and presented in terms of degrees of equivalence for entry in the BIPM key comparison database. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  7. Improving degradation of paracetamol by integrating gamma radiation and Fenton processes.

    PubMed

    Cruz-González, Germán; Rivas-Ortiz, Iram B; González-Labrada, Katia; Rapado-Paneque, Manuel; Chávez-Ardanza, Armando; Nuevas-Paz, Lauro; Jáuregui-Haza, Ulises J

    2016-10-14

    Degradation of paracetamol (N-(4-hydroxiphenyl)acetamide) in aqueous solution by gamma radiation, gamma radiation/H2O2 and gamma radiation/Fenton processes was studied. Parameters affecting the radiolysis of paracetamol such as radiation dose, initial concentration of pollutant, pH and initial oxidant concentration were investigated. Gamma radiation was performed using a (60)Co source irradiator. Paracetamol degradation and mineralization increased with increasing absorbed radiation dose, but decreased with increasing initial concentration of the drug in aqueous solution. The addition of H2O2 resulted in an increased effect on irradiation-driven paracetamol degradation in comparison with the performance of the irradiation-driven process alone: paracetamol removal increased from 48.9% in the absence of H2O2 to 95.2% for H2O2 concentration of 41.7 mmol/L. However, the best results were obtained with gamma radiation/Fenton process with 100% of the drug removal at 5 kGy, for optimal H2O2 and Fe(2+) concentrations at 13.9 and 2.3 mmol/L, respectively, with a high mineralization of 63.7%. These results suggest gamma radiation/H2O2 and gamma radiation/Fenton processes as promising methods for paracetamol degradation in polluted wastewaters.

  8. Secondary metabolite perturbations in Phaseolus vulgaris leaves due to gamma radiation.

    PubMed

    Ramabulana, T; Mavunda, R D; Steenkamp, P A; Piater, L A; Dubery, I A; Madala, N E

    2015-12-01

    Oxidative stress is a condition in which the balance between the production and elimination of reactive oxygen species (ROS) is disturbed. However, plants have developed a very sophisticated mechanism to mitigate the effect of ROS by constantly adjusting the concentration thereof to acceptable levels. Electromagnetic radiation is one of the factors which results in oxidative stress. In the current study, ionizing gamma radiation generated from a Cobalt-60 source was used to induce oxidative stress in Phaseolus vulgaris seedlings. Plants were irradiated with several radiation doses, with 2 kGy found to be the optimal, non-lethal dose. Metabolite distribution patterns from irradiated and non-irradiated plants were analyzed using UHPLC-qTOF-MS and multivariate data models such as principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA). Metabolites such as hydroxycinnamic phenolic acids, flavonoids, terpenes, and a novel chalcone were found to be perturbed in P. vulgaris seedlings treated with the aforementioned conditions. The results suggest that there is a compensatory link between constitutive protectants and inducible responses to injury as well as defense against oxidative stress induced by ionizing radiation. The current study is also the first to illustrate the power of a metabolomics approach to decipher the effect of gamma radiation on crop plants.

  9. Collagen I confers gamma radiation resistance.

    PubMed

    Azorin, E; González-Martínez, P R; Azorin, J

    2012-12-01

    The effect of collagen on the response of somatomammotroph tumor cells (GH3) to gamma, radiation therapy was studied in vitro. After incubating confluent GH3 cell monolayers in a serum-free, maintaining medium, either with or without collagen, the monolayers were irradiated with 137Cs, gamma radiation. Collagen reduces cell mortality via ERK1/2 activation, abolishing gamma radiation, cell death, and promotes cell invasion when acting in synergy with collagen and in association with the, MAPK/ERK1/2 signaling pathway activation. The presence of collagen in somatomammotroph tumors, confers resistance to radiation.

  10. Gamma radiation characteristics of plutonium dioxide fuel

    NASA Technical Reports Server (NTRS)

    Gingo, P. J.

    1969-01-01

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

  11. Dibasic calcium phosphate dihydrate, USP material compatibility with gamma radiation

    NASA Astrophysics Data System (ADS)

    Betancourt Quiles, Maritza

    Gamma radiation is a commonly used method to reduce the microbial bioburden in compatible materials when it is applied at appropriate dose levels. Gamma irradiation kills bacteria and mold by breaking down the organism’s DNA and inhibiting cell division. The purpose of this study is to determine the radiation dosage to be used to treat Dibasic Calcium Phosphate Dihydrate, USP (DCPD) and to evaluate its physicochemical effects if any, on this material. This material will be submitted to various doses of gamma radiation that were selected based on literature review and existing regulations that demonstrate that this method is effective to reduce or eliminate microbial bioburden in natural source and synthetic materials. Analytical testing was conducted to the DCPD exposed material in order to demonstrate that gamma radiation does not alter the physicochemical properties and material still acceptable for use in the manufacture of pharmaceutical products. The results obtained through this study were satisfactory and demonstrated that the gamma irradiation dosages from 5 to 30 kGy can be applied to DCPD without altering its physicochemical properties. These are supported by the Assay test data evaluation of lots tested before and after gamma irradiation implementation that show no significant statistical difference between irradiated and non irradiated assay results. The results of this study represent an achievement for the industry since they provide as an alternative the use of Gamma irradiation technology to control the microbial growth in DCPD.

  12. Gamma radiation effects on siloxane-based additive manufactured structures

    NASA Astrophysics Data System (ADS)

    Schmalzer, Andrew M.; Cady, Carl M.; Geller, Drew; Ortiz-Acosta, Denisse; Zocco, Adam T.; Stull, Jamie; Labouriau, Andrea

    2017-01-01

    Siloxane-basedadditive manufactured structures prepared by the direct ink write (DIW) technology were exposed to ionizing irradiation in order to gauge radiolysis effects on structure-property relationships. These well-defined 3-D structures were subjected to moderate doses of gamma irradiation in an inert atmosphere and characterized by a suite of experimental methods. Changes in thermal, chemical, microstructure, and mechanical properties were evaluated by DSC, TGA, FT-IR, mass spectroscopy, EPR, solvent swelling, SEM, and uniaxial compressive load techniques. Our results demonstrated that 3-D structures made from aromatic-free siloxane resins exhibited hardening after being exposed to gamma radiation. This effect was accompanied by gas evolution, decreasing in crystallization levels, decreasing in solvent swelling and damage to the microstructure. Furthermore, long-lived radiation-induced radicals were not detected by EPR methods. Our results are consistent with cross-link formation being the dominant degradation mechanism over chain scission reactions. On the other hand, 3-D structures made from high phenyl content siloxane resins showed little radiation damage as evidenced by low off gassing.

  13. Titanium-Water Thermosyphon Gamma Radiation Exposure and Results

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    Titanium-water thermosyphons are being considered for use in heat rejection systems for fission power systems. Their proximity to the nuclear reactor will result in some gamma irradiation. Noncondensable gas formation from radiation-induced breakdown of water over time may render portions of the thermosyphon condenser inoperable. A series of developmental thermosyphons were operated at nominal operating temperature under accelerated gamma irradiation, with exposures on the same order of magnitude as that expected in 8 years of heat rejection system operation. Temperature data were obtained during exposure at three locations on each thermosyphon: evaporator, condenser, and condenser end cap. Some noncondensable gas was evident; however, thermosyphon performance was not affected because the noncondensable gas was compressed into the fill tube region at the top of the thermosyphon, away from the heat rejecting fin. The trend appeared to be an increasing amount of noncondensable gas formation with increasing gamma irradiation dose. Hydrogen is thought to be the most likely candidate for the noncondensable gas and hydrogen is known to diffuse through grain boundaries. Post-exposure evaluation of one thermosyphon in a vacuum chamber and at temperature revealed that the noncondensable gas diffused out of the thermosyphon over a relatively short period of time. Further research shows a number of experimental and theoretical examples of radiolysis occurring through gamma radiation alone in pure water.

  14. RBE (relative biological effectiveness) of tritium beta radiation to gamma radiation and x-rays analyzed by both molecular and genetic methods

    SciTech Connect

    Lee, W.R.

    1988-01-01

    The relative biological effectiveness (RBE) of tritium beta radiation to /sup 60/Co gamma radiation was determined using sex-linked recessive lethals (SLRL) induced in Drosophila melanogaster spermatozoa as the biological effect. The SLRL test, a measure of mutations induced in germ cells transmitted through successive generations, yields a linear dose-response curve in the range used in these experiments. From these ratios of the slopes of the /sup 3/H beta and the /sup 60/ Co gamma radiation linear dose response curves, an RBE of 2.7 is observed. When sources of error are considered, this observation suggests that the tritium beta particle is 2.7 /plus minus/ 0.3 times more effective per unit of energy absorbed in inducing gene mutations transmitted to successive generation than /sup 60/Co gamma radiation. Ion tracks with a high density of ions (high LET) are more efficient than tracks with a low ion density (low LET) in inducing transmissible mutations, suggesting interaction among products of ionization. Molecular analysis of x-ray induced mutations shows that most mutations are deletions ranging from a few base pairs as determined from sequence data to multi locus deletions as determined from complementation tests and Southern blots. 14 refs., 1 fig.

  15. Synthesis of high-molecular-weight polymer of methyl chloride salt of N,N-dimethylaminoethyl methacrylate by radiation-induced polymerization at high pressure. [Gamma radiation

    SciTech Connect

    Ishigaki, I.; Okada, T.; Sasuga, T.; Takehisa, M.; Machi, S.

    1981-02-01

    Polymer of the methyl chloride salt of N,N-dimethylaminoethyl methacrylate and its copolymer with acrylamide are used as cationic flocculants for the treatment of waste water containing organic suspensions. As reported, radiation-induced polymerization is one of the most convenient methods because of its temperature independence of initiation and extremely large G-value. In general, a flocculant with higher molecular weight has larger flocculation effects. The high-molecular-weight products were prepared in high monomer concentration and a low dose rate. This paper concerns the polymerization and copolymerization of methyl chloride salt of N,N-dimethylaminoethyl methacrylate at high pressure, up to 7000 kg/cm/sup 2/, providing high-molecular-weight cationic flocculants.

  16. Long period grating response to gamma radiation

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Stǎncalie, Andrei; Neguţ, Daniel; Delepine-Lesoille, Sylvie; Lablonde, Laurent

    2016-04-01

    We report the evaluation of one long period grating (LPG) and one fiber Bragg grating (FBG) under gamma irradiation. The LPG was produced by the melting-drawing method based on CO2 laser assisted by a micro-flame and was engraved in a commercial single mode fiber SMF28 from Corning, grating length 25 mm, grating pitch of 720 μm. After the manufacturing of the grating, the fiber was re-coated with Acrylate and the grating was inserted into special ceramic case transparent to gamma radiation. The FBG is commercialized by Technica SA, and it is written in SMF-28 optical fiber (λ= 1546 nm; grating length of 12 mm; reflectivity > 80 %; bandwidth - BW @3 dB < 0.3 nm; side lobe suppress ratio - SLSR >15 dB; Acrylate recoating). By on-line monitoring of the LPG wavelength deep with an optical fiber interrogator during the irradiation exposure and pauses, both the irradiation induced shift (maximum 1.45 nm) and the recovery (in the range of 200 pm) phenomena were observed. Temperature sensitivity of the LPS was not affected by gamma irradiation.

  17. Apparatus and method for detecting gamma radiation

    DOEpatents

    Sigg, R.A.

    1994-12-13

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

  18. Apparatus and method for detecting gamma radiation

    DOEpatents

    Sigg, Raymond A.

    1994-01-01

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

  19. Caffeine does not cause override of the G2/M block induced by UVc or gamma radiation in normal human skin fibroblasts

    PubMed Central

    Deplanque, G; Vincent, F; Mah-Becherel, M C M; Cazenave, J-P; Bergerat, J-P; Klein-Soyer, C

    2000-01-01

    Caffeine has for many years been known to be involved in the sensitization of DNA to damage. One potential mechanism recently put forward is an override of the G2/M block induced by irradiation, which would leave the cells less time for DNA repair prior to mitosis. However, different cell types display a variety of responses and no clear pathway has yet emerged, especially as little is known about the capacity of this agent to enhance DNA damage in normal, untransformed cells. Continuous exposure to commonly used caffeine concentrations (1–5 mM) inhibited the proliferation of normal human fibroblasts (NHFs) in a dose-dependent manner to up to 80% at 5 mM. Exposure of exponentially growing NHFs to UVc radiation (20 J m–2) or γ radiation (2.5–8 Gy) led to a 45–60% inhibition of proliferation and protracted accumulation of cells in the G2/M phase. Addition of 2 mM caffeine after irradiation induced slowing of the S phase passage, with a resultant delay in G2/M accumulation mimicking a G2/M block override. These results were confirmed by stathmokinetic studies, which showed delayed entry of the cells into mitosis in the presence of caffeine. Our data demonstrate that caffeine primarily inhibits replicative DNA synthesis and suggest that, at least in normal cells, caffeine potentiates the cytotoxicity of radiation by intervening in DNA repair rather than by overriding the G2/M block. © 2000 Cancer Research Campaign PMID:10917550

  20. The shape of the dose-response curve for radiation-induced neoplastic transformation in vitro: evidence for an adaptive response against neoplastic transformation at low doses of low-LET radiation.

    PubMed

    Redpath, J L; Liang, D; Taylor, T H; Christie, C; Elmore, E

    2001-12-01

    A dose-response curve for gamma-radiation-induced neoplastic transformation of HeLa x skin fibroblast human hybrid cells over the dose range 0.1 cGy to 1 Gy is presented. In the experimental protocol used, the spontaneous (background) frequency of neoplastic transformation of sham-irradiated cultures was compared to that of cultures which had been irradiated with (137)Cs gamma radiation and either plated immediately or held for 24 h at 37 degrees C prior to plating, for assay for neoplastic transformation. The pooled data from a minimum of three repeat large-scale experiments at each dose demonstrated a reduced transformation frequency for the irradiated compared to the sham-irradiated cells for doses of 0.1, 0.5, 1, 5 and 10 cGy for the delayed-plating arm. The probability of this happening by chance is given by 1/2(n), where n is the number of observations (5); i.e., 1/32 congruent with 0.031. This is indicative of an adaptive response against spontaneous neoplastic transformation at least up to a dose of 10 cGy of gamma radiation. The high-dose data obtained at 30 and 50 cGy and 1 Gy showed a good fit to a linear extrapolation through the sham-irradiated, zero-dose control. The delayed-plating data at 10 cGy and below showed a statistically significant divergence from this linear extrapolation.

  1. Low dose radiation-induced endothelial cell retraction.

    PubMed

    Kantak, S S; Diglio, C A; Onoda, J M

    1993-09-01

    We characterized in vitro the effects of gamma-radiation (12.5-100 cGy) on pulmonary microvascular endothelial cell (PMEC) morphology and F-actin organization. Cellular retraction was documented by phase-contrast microscopy and the organization of actin microfilaments was determined by immunofluorescence. Characterization included radiation dose effects, their temporal duration and reversibility of the effects. A dose-dependent relationship between the level of exposure (12.5-100 cGy) and the rate and extent of endothelial retraction was observed. Moreover, analysis of radiation-induced depolymerization of F-actin microfilament stress fibres correlated positively with the changes in PMEC morphology. The depolymerization of the stress fibre bundles was dependent on radiation dose and time. Cells recovered from exposure to reform contact inhibited monolayers > or = 24 h post-irradiation. Concomitantly, the depolymerized microfilaments reorganized to their preirradiated state as microfilament stress fibres arrayed parallel to the boundaries of adjacent contact-inhibited cells. The data presented here are representative of a series of studies designed to characterize low-dose radiation effects on pulmonary microvascular endothelium. Our data suggest that post-irradiation lung injuries (e.g. oedema) may be induced with only a single fraction of therapeutic radiation, and thus microscopic oedema may initiate prior to the lethal effects of radiation on the microvascular endothelium, and much earlier than would be suggested by the time course for clinically-detectable oedema.

  2. Inspection of cargo containers using gamma radiation

    NASA Astrophysics Data System (ADS)

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

    1997-02-01

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

  3. 30 CFR 57.5047 - Gamma radiation surveys.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Gamma radiation surveys. 57.5047 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047 Gamma radiation surveys. (a) Gamma radiation surveys shall be conducted annually in all underground mines...

  4. 30 CFR 57.5047 - Gamma radiation surveys.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Gamma radiation surveys. 57.5047 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047 Gamma radiation surveys. (a) Gamma radiation surveys shall be conducted annually in all underground mines...

  5. 30 CFR 57.5047 - Gamma radiation surveys.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Gamma radiation surveys. 57.5047 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047 Gamma radiation surveys. (a) Gamma radiation surveys shall be conducted annually in all underground mines...

  6. 30 CFR 57.5047 - Gamma radiation surveys.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Gamma radiation surveys. 57.5047 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047 Gamma radiation surveys. (a) Gamma radiation surveys shall be conducted annually in all underground mines...

  7. 30 CFR 57.5047 - Gamma radiation surveys.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Gamma radiation surveys. 57.5047 Section 57..., Radiation, Physical Agents, and Diesel Particulate Matter Radiation-Underground Only § 57.5047 Gamma radiation surveys. (a) Gamma radiation surveys shall be conducted annually in all underground mines...

  8. Proximity of Radiation Desiccation Response Motif to the core promoter is essential for basal repression as well as gamma radiation-induced gyrB gene expression in Deinococcus radiodurans.

    PubMed

    Anaganti, Narasimha; Basu, Bhakti; Mukhopadhyaya, Rita; Apte, Shree Kumar

    2017-03-02

    The radioresistant D. radiodurans regulates its DNA damage regulon (DDR) through interaction between a 17bp palindromic cis-regulatory element called the Radiation Desiccation Response Motif (RDRM), the DdrO repressor and a protease IrrE. The role of RDRM in regulation of DDR was dissected by constructing RDRM sequence-, position- or deletion-variants of Deinococcal gyrB gene (DR0906) promoter and by RDRM insertion in the non-RDRM groESL gene (DR0606) promoter, and monitoring the effect of such modifications on the basal as well as gamma radiation inducible promoter activity by quantifying fluorescence of a GFP reporter. RDRM sequence-variants revealed that the conservation of sequence at the 5th and 13th position and the ends of RDRM is essential for basal repression by interaction with DdrO. RDRM position-variants showed that the sequence acts as a negative regulatory element only when located around transcription start site (TSS) and within the span of RNA polymerase (RNAP) binding region. RDRM deletion-variants indicated that the 5' sequence of RDRM possibly possesses an enhancer-like element responsible for higher expression yields upon repressor clearance post-irradiation. The results suggest that RDRM plays both a negative as well as a positive role of in the regulation of DDR in D. radiodurans.

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

    NASA Astrophysics Data System (ADS)

    Suljovrujic, E.; Micic, M.

    2015-01-01

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

  10. Gamma radiation effects on time-dependent iodine partitioning

    SciTech Connect

    Marshall, P.W.; Lutz, J.B.; Kelly, J.L.

    1987-03-01

    A need for characterization of the iodine source term used in safety calculations for hypothesized light water reactor core disruptive accidents has motivated a study in iodine volatility. Previous experimental studies have been directed at evaluating volatility of iodine at a single time shortly (1 to 12 h) after introduction into the aqueous phase. The very important variables of time in solution and gamma radiation dose rate for a range of iodine concentrations (10/sup -8/ to 10/sup -5/ gI/ml) and pHs (5, 9, and 11) are explored. All experiments were performed at --25/sup 0/C, first in the absence of a significant radiation field and later with a gamma radiation dose rate ranging from 0.003 to 0.06 Mrad/h. Iodine was introduced as either molecular I/sub 2/ or NaI with /sup 131/I (8.04-day half-life) as a tracer. Results of experiments with nonirradiated systems indicated very little volatility with NaI-initiated studies. The I/sub 2/-initiated systems at pH 5 were the most volatile whereas experiments at pH 9 and 11 showed decreasing iodine volatility with time. From the experiments at pH 9, it is inferred that the partition coefficient of HOI is -- 1000.

  11. EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS

    SciTech Connect

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

    2009-04-21

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

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

    PubMed

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

    2013-01-01

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

  13. Curcumin Regulates Low-Linear Energy Transfer {gamma}-Radiation-Induced NF{kappa}B-Dependent Telomerase Activity in Human Neuroblastoma Cells

    SciTech Connect

    Aravindan, Natarajan; Veeraraghavan, Jamunarani; Madhusoodhanan, Rakhesh; Herman, Terence S.; Natarajan, Mohan

    2011-03-15

    Purpose: We recently reported that curcumin attenuates ionizing radiation (IR)-induced survival signaling and proliferation in human neuroblastoma cells. Also, in the endothelial system, we have demonstrated that NF{kappa}B regulates IR-induced telomerase activity (TA). Accordingly, we investigated the effect of curcumin in inhibiting IR-induced NF{kappa}B-dependent hTERT transcription, TA, and cell survival in neuroblastoma cells. Methods and Materials: SK-N-MC or SH-SY5Y cells exposed to IR and treated with curcumin (10-100 nM) with or without IR were harvested after 1 h through 24 h. NF{kappa}B-dependent regulation was investigated either by luciferase reporter assays using pNF{kappa}B-, pGL3-354-, pGL3-347-, or pUSE-I{kappa}B{alpha}-Luc, p50/p65, or RelA siRNA-transfected cells. NF{kappa}B activity was analyzed using an electrophoretic mobility shift assay and hTERT expression using the quantitative polymerase chain reaction. TA was determined using the telomerase repeat amplification protocol assay and cell survival using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertrazolium bromide and clonogenic assay. Results: Curcumin profoundly inhibited IR-induced NF{kappa}B. Consequently, curcumin significantly inhibited IR-induced TA and hTERT mRNA at all points investigated. Furthermore, IR-induced TA is regulated at the transcriptional level by triggering telomerase reverse transcriptase (TERT) promoter activation. Moreover, NF{kappa}B becomes functionally activated after IR and mediates TA upregulation by binding to the {kappa}B-binding region in the promoter region of the TERT gene. Consistently, elimination of the NF{kappa}B-recognition site on the telomerase promoter or inhibition of NF{kappa}B by the I{kappa}B{alpha} mutant compromises IR-induced telomerase promoter activation. Significantly, curcumin inhibited IR-induced TERT transcription. Consequently, curcumin inhibited hTERT mRNA and TA in NF{kappa}B overexpressed cells. Furthermore, curcumin enhanced

  14. Inactivation of aflatoxin B1 by using the synergistic effect of hydrogen peroxide and gamma radiation

    SciTech Connect

    Patel, U.D.; Govindarajan, P.; Dave, P.J. )

    1989-02-01

    Inactivation of aflatoxin B1 was studied by using gamma radiation and hydrogen peroxide. A 100-krad dose of gamma radiation was sufficient to inactivate 50 micrograms of aflatoxin B1 in the presence of 5% hydrogen peroxide, and 400 krad was required for total degradation of 100 micrograms of aflatoxin in the same system. Degradation of aflatoxin B1 was confirmed by high-pressure liquid chromatographic and thin-layer chromatographic analysis. Ames microsomal mutagenicity test showed loss of aflatoxin activity. This method of detoxification also reduces the toxin levels effectively in artificially contaminated groundnuts.

  15. Gamma Radiation Effects on Peanut Skin Antioxidants

    PubMed Central

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

    2012-01-01

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

  16. Gamma radiation effects on peanut skin antioxidants.

    PubMed

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

    2012-01-01

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

  17. Gamma-radiation-induced grafting of binary mixture of methacrylic acid and 4-vinyl pyridine onto Teflon-FEP film as an effective polar membrane for separation processes

    NASA Astrophysics Data System (ADS)

    Kaur, Inderjeet; Rattan, Sunita; Chauhan, Sandeep; Gupta, Nitika

    2010-05-01

    Ionic bifunctional membranes have been synthesized by grafting binary mixture of methacrylic acid (MAAc) and 4-vinyl pyridine (4-VP) onto Teflon-FEP film by pre-irradiation method. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters. Maximum percentage of grafting of binary mixture (MAAc-co-4-VP) (71.29%) was obtained at an optimum total dose of 54.48 kGy and the total concentration was 9.49 mol/L ([4-VP] = 0.07 mol/L and [MAAc ] = 9.42 mol/L) in 5 ml of water. The effect of alcohols as additives to the reaction medium on percent grafting of the binary mixture has also been studied. The membranes were characterized by FTIR spectroscopy, scanning electron microscopy and thermogravimetric analysis. Swelling studies of the membranes were performed in different solvents such as water, benzene, carbon tetrachloride and dimethyl formamide (DMF). Maximum swelling was observed in DMF with minimum swelling in benzene. Metal ion (Cu 2+, Ni 2+ and Fe 2+) uptake studies show better affinity for Fe 2+ ions. Conductance measurements in different aqueous salt solution showed that these membranes have affinity for Na +/K + ions and Cl - ions and hence can be used in desalination/separation processes for the separation of both type of cationic and anionic ions.

  18. UVB and gamma-radiation induce the expression of mRNAs encoding the ribosomal subunit L13A in rat keratinocytes.

    PubMed

    Shahmolky, N; Lefebvre, D L; Poon, R; Bai, Y; Sharma, M; Rosen, C F

    1999-09-01

    Ultraviolet B radiation produces an array of cellular perturbations in the skin. We isolated a keratinocyte cDNA encoding the rat 60S ribosomal subunit protein L13a following differential cDNA library screening with UVB-enriched probes. In contrast to the reported structure of liver L13a, the keratinocyte L13a cDNA contains a longer 3'-untranslated region. Northern blot analysis detected two L13a mRNA transcripts, approximately 800 bp and approximately 1.2 kb, in keratinocytes and a variety of rat tissues. Both L13a mRNA transcripts were induced by UVB irradiation, forskolin and gamma-irradiation. In contrast, no induction of L13a mRNA transcript levels was observed following exposure of keratinocytes to 12-O-tetradecanoylphorbol-13-acetate, serum and the DNA damage-inducing agents methyl methanesulfonate or 4-nitroquinoline-N-oxide. These observations suggest that increased expression of ribosomal subunit genes may be a molecular component of the keratinocyte response to UVB in particular and not part of a nonspecific response to DNA damage.

  19. Mutant quantity and quality in mammalian cells (AL) exposed to cesium-137 gamma radiation: effect of caffeine

    NASA Technical Reports Server (NTRS)

    McGuinness, S. M.; Shibuya, M. L.; Ueno, A. M.; Vannais, D. B.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

    1995-01-01

    We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian AL human-hamster hybrid cells exposed to 137Cs gamma radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1- mutants by 137Cs gamma radiation. Molecular analysis of 235 S1- mutants using a series of DNA probes mapped to the human chromosome 11 in the AL hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, 137Cs gamma rays alone or 137Cs gamma rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These "complex" mutations were rare for 137Cs gamma irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by 137Cs gamma irradiation.

  20. Structural and chemical changes in ultra-high-molecular-weight polyethylene due to gamma radiation-induced crosslinking and annealing in air.

    PubMed

    Viano, A M; Spence, K E; Shanks, M A; Scott, M A; Redfearn, R D; Carlson, C W; Holm, T A; Ray, A K

    2007-01-01

    Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) is the material of choice for one of the articulating surfaces in many total joint replacements, notably hip and knee prostheses. The various methods used by the orthopaedic biomaterials industry to sterilize and anneal UHMWPE components, and the resulting oxidation and crosslinking, affect the mechanical wear resistance properties in ways still unknown at the microscopic and molecular levels. Transmission electron microscopy and chemical pyrolysis were used to quantify crosslinking induced by gamma irradiation and annealing in air. Changes in lamellar stacking and the amount of crosslinking suggest two types of crosslinking: relatively unstable crosslinks in the amorphous region initially resulting from gamma irradiation which are later replaced by more thermally stable crosslinks resulting from rearrangements at the annealing temperature. Lamellar mobility, the ability of crystalline lamellae to flow in the material, is enhanced during the transition from one type of bond to the other, and this appears to optimize near eight hours of annealing time. Results from decomposition and percent crystallinity measurements provide further support for this theory.

  1. Protective Role of Hsp27 Protein Against Gamma Radiation-Induced Apoptosis and Radiosensitization Effects of Hsp27 Gene Silencing in Different Human Tumor Cells

    SciTech Connect

    Aloy, Marie-Therese Hadchity, Elie; Bionda, Clara; Diaz-Latoud, Chantal; Claude, Line; Rousson, Robert; Arrigo, Andre-Patrick; Rodriguez-Lafrasse, Claire

    2008-02-01

    Purpose: The ability of heat shock protein 27 (Hsp27) to protect cells from stressful stimuli and its increased levels in tumors resistant to anticancer therapeutics suggest that it may represent a target for sensitization to radiotherapy. In this study, we investigate the protective role of Hsp27 against radiation-induced apoptosis and the effect of its attenuation in highly expressing radioresistant cancer cell lines. Methods and Materials: We examined clonogenic death and the kinetics of apoptotic events in different tumor cell lines overexpressing or underexpressing Hsp27 protein irradiated with photons. The radiosensitive Jurkat cell line, which does not express Hsp27 constitutively or in response to {gamma}-rays, was stably transfected with Hsp27 complementary DNA. Attenuation of Hsp27 expression was accomplished by antisense or RNAi (interfering RNA) strategies in SQ20B head-and-neck squamous carcinoma, PC3 prostate cancer, and U87 glioblastoma radioresistant cells. Results: We measured concentration-dependent protection against the cytotoxic effects of radiation in Jurkat-Hsp27 cells, which led to a 50% decrease in apoptotic cells at 48 hours in the highest expressing cells. Underlying mechanisms leading to radiation resistance involved a significant increase in glutathione levels associated with detoxification of reactive oxygen species, a delay in mitochondrial collapse, and caspase activation. Conversely, attenuation of Hsp27 in SQ20B cells, characterized by their resistance to apoptosis, sensitizes cells to irradiation. This was emphasized by increased apoptosis, decreased glutathione basal level, and clonogenic cell death. Sensitization to irradiation was confirmed in PC3 and U87 radioresistant cells. Conclusion: Hsp27 gene therapy offers a potential adjuvant to radiation-based therapy of resistant tumors.

  2. Effects of gamma radiation on perfluorinated polymer optical fibers

    NASA Astrophysics Data System (ADS)

    Stajanca, Pavol; Mihai, Laura; Sporea, Dan; Neguţ, Daniel; Sturm, Heinz; Schukar, Marcus; Krebber, Katerina

    2016-08-01

    The paper presents the first complex study of gamma radiation effects on a low-loss perfluorinated polymer optical fiber (PF-POF) based on Cytop® polymer. Influence of gamma radiation on fiber's optical, mechanical and climatic performance is investigated. The radiation-induced attenuation (RIA) in the visible and near-infrared region (0.4 μm-1.7 μm) is measured and its origins are discussed. Besides attenuation increase, radiation is also shown to decrease the thermal degradation stability of the fiber and to increase its susceptibility to water. With regard to complex fiber transmission performance upon irradiation, the optimal operation wavelength region of PF-POF-based systems intended for use in radiation environments is determined to be around 1.1 μm. On the other hand, the investigated fiber holds potential for low-cost RIA-based optical fiber dosimetry applications with sensitivity as high as 260 dBm-1/kGy in the visible region.

  3. Gamma -radiations connected to atmospheric precipitations

    NASA Astrophysics Data System (ADS)

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

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

  4. Gamma radiation shielding and health physics characteristics of diaspore-flyash concretes.

    PubMed

    Singh, Kanwaldeep; Singh, Sukhpal; Singh, S P; Mudahar, Gurmel S; Dhaliwal, A S

    2015-06-01

    Different gamma radiation interaction parameters has been measured experimentally for the prepared diaspore-flyash concretes at 59.54, 662, 1173 and 1332 keV using narrow-beam transmission geometry and results are found to be in good agreement with theoretical values computed with a computer programme, WinXCom. The radiation exposure rate and absorbed dose rate for the gamma radiation with and without shielding of diaspore-flyash concretes have been determined using linear attenuation results. The results show that on average, there is reduction of 95%, 53% and 40% in dose rate for gamma sources (241)Am, (137)Cs and (60)Co, respectively with diaspore-flyash concretes as shielding material. Other health physics parameters namely equivalent dose, effective dose, gamma flux and energy fluence rate have also been determined.

  5. Gamma response study of radiation sensitive MOSFETs for their use as gamma radiation sensor

    NASA Astrophysics Data System (ADS)

    Srivastava, Saurabh; Aggarwal, Bharti; Singh, Arvind; Kumar, A. Vinod; Topkar, Anita

    2016-05-01

    Continuous monitoring of gamma dose is important in various fields like radiation therapy, space-related research, nuclear energy programs and high energy physics experiment facilities. The present work is focused on utilization of radiation-sensitive Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) to monitor gamma radiation doses. Static characterization of these detectors was performed to check their expected current-voltage relationship. Threshold voltage and transconductance per unit gate to source voltage (K factor) were calculated from the experimental data. The detector was exposed to gamma radiation in both, with and without gate bias voltage conditions, and change in threshold voltage was monitored at different gamma doses. The experimental data was fitted to obtain equation for dependence of threshold voltage on gamma dose. More than ten times increase in sensitivity was observed in biased condition (+3 V) compared to the unbiased case.

  6. Gamma radiation induced resistivity changes in Iron

    NASA Astrophysics Data System (ADS)

    Tundwal, Ambika; Kumar, V.; Datta, A.

    2017-03-01

    Monte Carlo Code JA-IPU is used for estimation of Frenkel pairs and their effect on change of resistivity of Iron on irradiation by gamma spectrum of Co60. The Code includes three cascade processes of incident gamma, produced electrons and recoiled atoms and simulation of the lattice structure of the target material. Change in experimentally measured resistivity of Iron is found to vary with number of Frenkel pairs as (x - 1) ln N d .

  7. Composition and apparatus for detecting gamma radiation

    DOEpatents

    Hofstetter, Kenneth J.

    1994-01-01

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

  8. Composition and apparatus for detecting gamma radiation

    DOEpatents

    Hofstetter, K.J.

    1994-08-09

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

  9. Effects of gamma-Radiation on Select Lipids and Antioxidants

    NASA Technical Reports Server (NTRS)

    Gandolph, Jacob; Mauer, Lisa; Perchonok, Michele

    2006-01-01

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

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

    SciTech Connect

    Hamilton, B.F.; Benjamin, S.A.; Angleton, G.M.; Lee, A.C. )

    1989-08-01

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

  11. Perfluorinated polymer optical fiber for gamma radiation monitoring

    NASA Astrophysics Data System (ADS)

    Stajanca, P.; Mihai, L.; Sporea, D.; Negut, D.; Krebber, K.

    2016-05-01

    The sensitivity of low-loss perfluorinated polymer optical fiber (PF-POF) to gamma radiation is investigated for on-line radiation monitoring purposes. The radiation-induced attenuation (RIA) of a commercial PF-POF based on Cytop material is measured in the visible spectral region. The fiber RIA shows strong wavelength dependence with rapid increase towards the blue side of the spectrum. The wide range of radiation sensitivities is available via careful selection of appropriate monitoring wavelength. The accessible sensitivities span from 1.6 +/- 0.2 dBm-1/kGy measured at 750 nm to 18.3 +/- 0.7 dBm-1/kGy measured at 420 nm. The fairly high radiation sensitivity as well as its wide tunability makes the fiber a promising candidate for a broad range of applications.

  12. SSPM Scintillator Readout for Gamma Radiation Detection

    SciTech Connect

    Baker, S A; Wendelberger, B; Young, J A; Green, J A; Guise, R E; Franks, L; Staples, C

    2011-09-01

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

  13. SSPM scintillator readout for gamma radiation detection

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  14. Formulation of a nasogastric liquid feed and shelf-life extension using gamma radiation.

    PubMed

    Hajare, Sachin N; Gautam, Satyendra; Nair, Anjali B; Sharma, Arun

    2014-08-01

    Nasogastric liquid feed formulation (NGLF) was developed for immunocompromised patients who are vulnerable targets of pathogenic assault. NGLF consisted of cereals, pulses, vegetables, and milk powder to provide balanced nutrients; however, the shelf life was only a few hours because this product was highly prone to microbial contamination and proliferation due to its high water content and rich nutrients. Postpreparation storage and distribution was very difficult, even at chilled temperatures. To overcome this problem, the NGLF was irradiated at various doses (2.5 to 10 kGy). Gamma irradiation at 10 kGy reduced the microbial load to nondetectable levels, and the product could be stored up to 1 month without any detectable increase in microbial load. The sensory evaluation did not indicate differences between the nonirradiated fresh, irradiated fresh, and stored samples. Nutritional quality in terms of total carbohydrates, dietary fiber, proteins, calories, vitamins A and C, and the micronutrients calcium, iron, and zinc was not affected by irradiation. NGLF also possessed antimutagenic potential against ethylmethanesulphonate-induced mutagenesis in Escherichia coli cells as evaluated by the rifampin resistance assay. This property of NGLF remained unchanged even after exposure to a 10-kGy dose of gamma radiation. Thus, irradiated NGLF seemed to be a safe and wholesome food for immunocompromised patients.

  15. Gamma Radiation Reduced Toxicity of Azoxystrobin Tested on Artemia franciscana.

    PubMed

    Dvorak, P; Zdarsky, M; Benova, K; Falis, M; Tomko, M

    2016-06-01

    Fungicide azoxystrobin toxicity was monitored by means of a 96-h biotest with Artemia franciscana nauplius stages after exposure to solutions with concentrations of 0.2, 0.4, 0.6 and 0.8 mg L(-1) irradiated with (60)Co gamma radiation with doses of 1, 2.5, 5 and 10 kGy. The effects of ionization radiation on azoxystrobin toxicity were mainly manifested by a statistically significant reduction of lethality after 72- and 96-h exposure. A maximum reduction of lethality of 72 % was achieved using doses of 1-5 kGy for an azoxystrobin initial concentration of 0.4 mg L(-1) and after 72 h of exposure. At a 96-h exposure, a difference of lethal effects reached up to 70 % for a dose of 10 kGy. The observed effect of gamma ionizing radiation on azoxystrobin toxicity suggest that this approach can be applied as an alternative for a reduction of azoxystrobin residua in food.

  16. [Protection of cadaver tissues exposed to high gamma radiation].

    PubMed

    Matus-Jiménez, J; Flores-Fletes, J R; Carrillo, A

    2013-01-01

    Bone tissue is the most widely used tissue for the treatment of various conditions. As a result of this, allografts are used at an increasing frequency and processes for their harvest, preservation and sterilization have improved. The sterilization method that grants the greatest sterilization is high-dose gamma radiation, which destroys prions and any microorganism thus assuring that patients will not experience any infection. But given that radiation use has proven to deteriorate bone and tendon tissue, efforts have been made to protect the latter. One way to do this is a commercially available substance called Clearant. Studies conducted elsewhere have found that it does protect bone and tendon tissue. This study was therefore conducted with allograft samples exposed to high-dose radiation. Its purpose was to assess, with photon microscopy using various dyes and electron microscopy, the presence of color changes as well as the destruction of the anatomical structure. The same tissue was followed-up throughout the process until it was placed in the patient. The review found no structural changes in bone and tendon tissues exposed to high radiation doses (60 kilograys) when the Clearant process was used, and concluded that the former may be used safely in orthopedic or traumatologic diseases.

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

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

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

  18. Coffee-mediated protective effects against directly acting genotoxins and gamma-radiation in mouse lymphoma cells.

    PubMed

    Abraham, S K; Vukicevic, V; Stopper, H

    2004-03-01

    The cytokinesis-block micronucleus test was performed using L5178Y mouse lymphoma cells to ascertain whether or not standard (caffeinated) instant coffee, the commonly consumed polyphenolic beverage with antioxidant activity can protect against chromosomal damage induced by the directly acting agents N-methyl-N-nitro-N-nitrosoguanidine (MNNG), mitomycin C (MMC), methyl methanesulfonate (MMS) and gamma radiation. Our results demonstrated significant reductions in the in vitro genotoxic effects of MNNG, MMC, and MMS following co-treatment of mouse lymphoma cells with standard instant coffee. Subsequently, the comet assay was carried out to assess the effect of coffee co-treatment on the level of DNA damage induced by MMS in mouse lymphoma cells. The results demonstrated a significant reduction in MMS-induced DNA damage following co-treatment with standard instant coffee. Protective effects were observed in mouse lymphoma cells which were treated with coffee immediately after exposure to gamma radiation (1 and 2 Gy). Another experiment showed protection when the mammalian cells were irradiated (0.5 and 1 Gy) midway (at 2 h) during a 4 h coffee treatment. However, the protective effect against the lower dose (0.5 Gy) was not significant. In addition we assessed the modulatory effect of coffee on MNNG-induced apoptotic frequency by flow cytometry. The results revealed only a minor influence of coffee on the frequency of apoptotic cells induced by the test compounds, rendering an increase in sensitivity for apoptosis as a reason for the reduced genomic damage an unlikely or at least incomplete explanation.

  19. Effect of gamma radiation on resting B lymphocytes. I. Oxygen-dependent damage to the plasma membrane results in increased permeability and cell enlargement

    SciTech Connect

    Ashwell, J.D.; Schwartz, R.H.; Mitchell, J.B.; Russo, A.

    1986-05-15

    Although the susceptibility of resting B lymphocytes to radiation-induced interphase death is well known, the mechanism by which this occurs is not understood. In this report, we use three measures of plasma membrane integrity (increase in cell volume, uptake of trypan blue, and release of /sup 51/Cr) to assess the effect of radiation on the resting B cell plasma membrane. The delivery of 500 to 1000 rad caused the majority of resting B cells to enlarge slightly, whereas 3000 rad caused virtually all of the cells to approximately double in size within 3 to 4 hr. Measurement of the release of /sup 51/Cr from resting B cells revealed a similar relationship between the dose of radiation and the loss of radioactive label. Trypan blue exclusion was also found to diminish as a function of radiation dose. An analysis of a variety of lymphoid cells suggested that sensitivity to the membrane damaging effects of gamma radiation was in the order of resting B cells greater than resting T cells greater than a long-term L3T4+ T cell clone greater than a B cell lymphoma. LPS-induced B cell blasts treated with 3000 rad were equivalent to 1000 rad-treated resting B cells. The effects of the gamma radiation could be ameliorated by excluding oxygen at the time of irradiation, or by adding the free radical scavenging agent cysteamine. These data are compatible with the hypothesis that gamma radiation results in damage to the plasma membrane of resting lymphocytes via the generation of highly reactive free radical species. This damage is reflected in a rapid increase in plasma membrane permeability and swelling of the cells, and may play a major role in causing interphase death.

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  1. Characterization of methyl methacrylate grafting onto preirradiated biodegradable lignocellulose fiber by gamma-radiation.

    PubMed

    Khan, Ferdous

    2005-01-14

    Gamma-radiation-induced graft copolymerization of methyl methacrylate onto natural lignocellulose (jute) fiber was carried out by the preirradiation method in an aqueous medium by using octylphenoxy-polyethoxyethanol as an emulsifier. The different factors that influenced the graft copolymer reaction process were investigated. In the case of radiation-dose-dependent grafting, samples irradiated in the presence of air produced up to 73% graft weight compared to 53% obtained in the case of irradiation in a nitrogen environment. By assuming Arrhenius reaction kinetics, the activation energy (E(a)) of the grafting reaction process was evaluated for different reaction temperatures. Moreover, the graft copolymer reaction was controlled by incorporating a homopolymer-inhibiting agent and three different chain-transfer agents in the reaction medium. The mechanical and thermal properties of jute fiber 'as received' and jute-graft-poly(methyl methacrylate) were also investigated. The results showed that the percentage of grafting with jute fiber has a significant effect on the properties. The kinetic parameters were evaluated from TGA thermograms by using Broido's method in the temperature range 240-350 degrees C. Scanning electron micrographs show that the structural changes on the surface of jute fibers were induced by graft copolymerization of methyl methacrylate monomer. Fiber-fiber surface friction was measured in terms of the average maximum load and the kinetic friction. SEM of jute-graft-poly(methyl methacrylate).

  2. Gamma radiation effects on mechanical properties and morphology of a polyurethane derivate from castor oil

    NASA Astrophysics Data System (ADS)

    Azevedo, Elaine Cristina; Orivaldo Chierice, Gilberto; Claro Neto, Salvador; Scheidegger Soboll, Daniel; Mauro Nascimento, Eduardo; Lepienski, Carlos Mauricio

    2011-03-01

    In this study, an adhesive of a polyurethane derivate from castor oil was irradiated with gamma radiation from a 60Co source, at doses from 0.2 to 25 kGy. This adhesive polyurethane is considered for use in hospital furniture because it does not liberate dangerous solvents. Hardness and elastic modulus were measured by instrumented indentation with a pyramidal Berkovich indenter, using loads from 0.08-40 mN with a nanoindenter XP. The instrumented indentation hardness was 110 MPa for an untreated sample, increasing to 124 MPa after irradiation with 25 kGy, at penetration depths of about 5 μm. The increases in elastic modulus induced by radiation were less pronounced. This polyurethane is naturally cross-linked and the relative modifications in the hardness are attributed to an additional cross-linking process induced by radiation. X-ray diffraction indicates a slight increase in crystallinity. The roughness measured by atomic force microscopy increases after gamma irradiation.

  3. Usage of computational methods of gamma radiation transfer equation for estimating doses of population exposure due to nuclear power plant`s emergency releases of radionuclides (within the frame of a radioecological data base RECOR)

    SciTech Connect

    Bolibok, A.A.; Pitkevich, V.A.

    1993-12-31

    In this paper, the problem of the radioactive cloud dose evaluation for populated settlements has been raised. However, an available accuracy of such evaluation depends on the accuracy of initial data and of the used method. We conclude that the conservative dose models such as the semi-infinite uniform cloud model underestimate the dose absorbed in air at the ground for long-term releases. Nevertheless, we believe that it is necessary to verify the obtained results by comparison with experimental data and other models.

  4. Influence of gamma-radiation on the nutritional and functional qualities of lotus seed flour.

    PubMed

    Bhat, Rajeev; Sridhar, Kandikere Ramaiah; Karim, Alias A; Young, Chiu C; Arun, Ananthapadmanabha B

    2009-10-28

    In the present study, we investigated the physicochemical and functional properties of lotus seed flour exposed to low and high doses of gamma-radiation (0-30 kGy; the dose recommended for quarantine and hygienic purposes). The results indicated raw seed flour to be rich in nutrients with minimal quantities of antinutritional factors. Irradiation resulted in a dose-dependent increase in some of the proximal constituents. The raw and gamma-irradiated seeds meet the Food and Agricultural Organization-World Health Organization recommended pattern of essential amino acids. Some of the antinutritional factors (phytic acid, total phenolics, and tannins) were lowered with gamma-irradiation, while the seed flours were devoid of lectins, L-3,4-dihydroxyphenylalanine, and polonium-210. The functional properties of the seed flour were significantly improved with gamma-radiation. gamma-radiation selectively preserved or improved the desired nutritional and functional traits of lotus seeds, thus ensuring a safe production of appropriate nutraceutically valued products.

  5. Gamma radiation shielding analysis of lead-flyash concretes.

    PubMed

    Singh, Kanwaldeep; Singh, Sukhpal; Dhaliwal, A S; Singh, Gurmel

    2014-11-04

    Six samples of lead-flyash concrete were prepared with lead as an admixture and by varying flyash content - 0%, 20%, 30%, 40%, 50% and 60% (by weight) by replacing cement and keeping constant w/c ratio. Different gamma radiation interaction parameters used for radiation shielding design were computed theoretically and measured experimentally at 662keV, 1173keV and 1332keV gamma radiation energy using narrow transmission geometry. The obtained results were compared with ordinary-flyash concretes. The radiation exposure rate of gamma radiation sources used was determined with and without lead-flyash concretes.

  6. Inactivation of avirulent Yersinia pestis in Butterfield's phosphate buffer and frankfurters by UVC (254 nm) and gamma radiation.

    PubMed

    Sommers, Christopher H; Cooke, Peter H

    2009-04-01

    Yersinia pestis is the causative agent of plague. Although rare, pharyngeal plague in humans has been associated with consumption or handling of meat prepared from infected animals. The risks of contracting plague from consumption of deliberately contaminated food are currently unknown. Gamma radiation is a penetrating form of electromagnetic radiation, and UVC radiation is used for decontamination of liquids or food surfaces. Gamma radiation D10-values (the radiation dose needed to inactivate 1 log unit pathogen) were 0.23 (+/-0.01) and 0.31 (+/-0.03) kGy for avirulent Y. pestis inoculated into Butterfield's phosphate buffer and onto frankfurter surfaces, respectively, at 0 degree C. A UVC radiation dose of 0.25 J/cm2 inactivated avirulent Y. pestis suspended in Butterfield's phosphate buffer. UVC radiation doses of 0.5 to 4.0 J/cm2 inactivated 0.97 to 1.20 log units of the Y. pestis surface inoculated onto frankfurters. A low gamma radiation dose of 1.6 kGy could provide a 5-log reduction and a UVC radiation dose of 1 to 4 J/cm2 would provide a 1-log reduction of Y. pestis surface inoculated onto frankfurters. Y. pestis was capable of growth on frankfurters during refrigerated storage (10 degrees C). Gamma radiation of frankfurters inhibited the growth of Y. pestis during refrigerated storage, and UVC radiation delayed the growth of Y. pestis.

  7. Gamma radiation influence on technological characteristics of wheat flour

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  8. Gamma radiation effects on Sporothrix schenckii yeast cells.

    PubMed

    Lacerda, Camila Maria de Souza; Martins, Estefânia Mara do Nascimento; de Resende, Maria Aparecida; de Andrade, Antero Silva Ribeiro

    2011-06-01

    Sporotrichosis is a subcutaneous mycosis caused by Sporothrix schenckii. Zoonotic transmission to man can occur after scratches or bites of animals, mainly cats. In this study, the gamma radiation effects on yeast of S. schenckii were analyzed with a view of developing a radioattenuated vaccine for veterinary use. The cultures were irradiated at doses ranging from 1.0 to 9.0 kGy. The reproductive capacity was measured by the ability of cells to form colonies. No colonies could be recovered above 8.0 kGy, using inocula up to 10(7) cells. Nevertheless, yeast cells irradiated with 7.0 kGy already were unable to produce infection in immunosuppressed mice. Evaluation by the FungaLight™ Kit (Invitrogen) indicated that yeast cells remained viable up to 9.0 kGy. At 7.0 kGy, protein synthesis, estimated by the incorporation of [L-(35)S] methionine, continues at levels slightly lower than the controls, but a significant decrease was observed at 9.0 kGy. The DNA of 7.0 kGy irradiated cells, analyzed by electrophoresis in agarose gel, was degraded. Cytoplasmic vacuolation was the main change verified in these cells by transmission electron microscopy. The dose of 7.0 kGy was considered satisfactory for yeast attenuation since irradiated cells were unable to produce infection but retained viability, metabolic activity, and morphology.

  9. The Impact of Gamma Radiation on Sediment Microbial Processes

    PubMed Central

    Brown, Ashley R.; Boothman, Christopher; Pimblott, Simon M.

    2015-01-01

    Microbial communities have the potential to control the biogeochemical fate of some radionuclides in contaminated land scenarios or in the vicinity of a geological repository for radioactive waste. However, there have been few studies of ionizing radiation effects on microbial communities in sediment systems. Here, acetate and lactate amended sediment microcosms irradiated with gamma radiation at 0.5 or 30 Gy h−1 for 8 weeks all displayed NO3− and Fe(III) reduction, although the rate of Fe(III) reduction was decreased in 30-Gy h−1 treatments. These systems were dominated by fermentation processes. Pyrosequencing indicated that the 30-Gy h−1 treatment resulted in a community dominated by two Clostridial species. In systems containing no added electron donor, irradiation at either dose rate did not restrict NO3−, Fe(III), or SO42− reduction. Rather, Fe(III) reduction was stimulated in the 0.5-Gy h−1-treated systems. In irradiated systems, there was a relative increase in the proportion of bacteria capable of Fe(III) reduction, with Geothrix fermentans and Geobacter sp. identified in the 0.5-Gy h−1 and 30-Gy h−1 treatments, respectively. These results indicate that biogeochemical processes will likely not be restricted by dose rates in such environments, and electron accepting processes may even be stimulated by radiation. PMID:25841009

  10. Gamma Radiation Dose Rate in Air due to Terrestrial Radionuclides in Southern Brazil: Synthesis by Geological Units and Lithotypes Covered by the Serra do Mar Sul Aero-Geophysical Project

    SciTech Connect

    Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    The absorbed dose rates in air due to terrestrial radionuclides were estimated from aerial gamma spectrometric data for an area of 48,600 km{sup 2} in Southern Brazil. The source data was the Serra do Mar Sul Aero-Geophysical Project back-calibrated in a cooperative work among the Geological Survey of Brazil, the Geological Survey of Canada, and Paterson, Grant and Watson Ltd. The concentrations of eU (ppm), eTh (ppm) and K (%) were converted to dose rates in air (nGy{center_dot}h{sup -1}) by accounting for the contribution of each element's concentration. Regional variation was interpreted according to lithotypes and a synthesis was performed according to the basic geological units present in the area. Higher values of total dose were estimated for felsic igneous and metamorphic rocks, with average values varying up to 119{+-}24 nGy{center_dot}h{sup -1}, obtained by Anitapolis syenite body. Sedimentary, metasedimentary and metamafic rocks presented the lower dose levels, and some beach deposits reached the lowest average total dose, 18.5{+-}8.2 nGy{center_dot}h{sup -1}. Thorium gives the main average contribution in all geological units, the highest value being reached by the nebulitic gneisses of Atuba Complex, 71{+-}23 nGy{center_dot}h{sup -1}. Potassium presents the lowest average contribution to dose rate in 53 of the 72 units analyzed, the highest contribution being obtained by intrusive alkaline bodies (28{+-}12 nGy{center_dot}h{sup -1}). The general pattern of geographic dose distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.

  11. Satellite observation of atmospheric nuclear gamma radiation.

    PubMed

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

    1989-02-01

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

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

    PubMed Central

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

    2010-01-01

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

  13. Effect of high-power gamma-radiation on the /sup 90/Sr distribution in the ground

    SciTech Connect

    Sobolev, I.A.; Barinov, A.S.; Khomchik, L.M.; Ozhovan, M.I.; Timofeev, E.M.

    1986-02-01

    This paper examines the effect of gamma-radiation on the Sr-90 distribution in argillaceous soil. For the irradiated argillaceous ground specimens, the authors investigated the ion-exchange capacity and the Sr-90 distribution coefficient concentration in the solid phase to the Sr-90 concentration in the contacting equilibrium solution. The investigation of the irradiated ground samples has shown that the ion-exchange capacity remains virtually unchanged up to a total dose of 2.3 x 10/sup 8/ rd. The effect of gamma-radiation on the Sr-90 distribution coefficient was investigated in two series of experiments.

  14. Inactivation of rabies diagnostic reagents by gamma radiation

    SciTech Connect

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

    1980-11-01

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

  15. Effect of gamma radiation on morphological & optical properties of ZnO nanopowder

    NASA Astrophysics Data System (ADS)

    Qindeel, Rabia

    Gamma radiation is the most energetic, highly penetrating electromagnetic radiation with extremely high frequency. In this light, the influence of gamma irradiation on the morphological and the optical properties of zinc oxide (ZnO) nanopowder is investigated for different applications. In particular, the zinc oxide (ZnO) nanopowder is prepared by the homogenous precipitation method with the post-oxidation annealing taking place in air atmosphere. The optical properties of the ZnO nanopowder are observed using a UV-Vis spectrophotometer in the wavelength range of 200-800 nm, while scanning electron microscopy (SEM) is used for surface analysis. Samples are irradiated using a Co60 gamma source with high and low dose. The energy band gap of ZnO nanopowder is calculated before and after gamma radiation.

  16. Mutant quantity and quality in mammalian cells (A{sub L}) exposed to cesium-137 gamma radiation: Effect of caffeine

    SciTech Connect

    McGuinness, S.M.; Shibuya, M.L.; Ueno, A.M.

    1995-06-01

    We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian A{sub L} human-hamster hybrid cells exposed to {sup 137}Cs {gamma} radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1{sup {minus}} mutants by {sup 137}Cs {gamma} radiation. Molecular analysis of 235 S1{sup {minus}} mutants using a series of DNA probes mapped to the human chromosome 11 in the A{sub L} hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, {sup 137}Cs {gamma} rays alone or {sup 137}Cs {gamma} rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These {open_quotes}complex{close_quotes} mutations were rare for {sup 137}Cs {gamma} irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by {sup 137}Cs {gamma} irradiation. 62 refs., 3 figs., 3 tabs.

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

    PubMed

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

    2010-05-01

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

  18. Inactivation of murine norovirus-1 in the edible seaweeds Capsosiphon fulvescens and Hizikia fusiforme using gamma radiation.

    PubMed

    Park, Shin Young; Kang, Sujin; Ha, Sang-Do

    2016-06-01

    This study investigated the effects of gamma radiation (3-10 kGy) upon the inactivation of murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate. The edible green and brown algae, fulvescens (Capsosiphon fulvescens) and fusiforme (Hizikia fusiforme), respectively, were experimentally contaminated with 5-6 log10 plaque forming units (PFU)/ml MNV-1. The titer of MNV-1 significantly decreased (P < 0.05) as the dose of gamma radiation increased. MNV-1 titer decreased to 1.16-2.46 log10 PFU/ml in fulvescens and 0.37-2.21 log10 PFU/ml in fusiforme following irradiation. However, all Hunters ('L', 'a' and 'b') and sensory qualities (appearance, color, flavor, texture and overall acceptability) were not significantly (P > 0.05) different in both algae following gamma radiation. The Weibull model was used to generate non-linear survival curves and to calculate Gd values for 1, 2, and 3 log10 reductions of MNV-1 in fulvescens (R(2) = 0.992) and fusiforme (R(2) = 0.988). A Gd value of 1 (90% reduction) corresponded to 2.89 and 3.93 kGy in fulvescens and fusiforme, respectively. A Gd value of 2 (99% reduction) corresponded to 7.75 and 9.02 kGy in fulvescens and fusiforme, respectively, while a Gd value of 3 (99.9% reduction) in fulvescens and fusiforme corresponded with 13.83 and 14.93 kGy of gamma radiation, respectively. A combination of gamma radiation at medium doses and other treatments could be used to inactivate ≥ 3 log10 PFU/ml NoV in seaweed. The inactivation kinetics due to gamma radiation against NoV in these algae might provide basic information for use in seaweed processing and distribution.

  19. Selection of putative Terra Maranhão plantain cultivar mutants obtained by gamma radiation.

    PubMed

    Reis, R V; Amorim, E P; Ledo, C A S; Pestana, R K N; Gonçalves, Z S; Borém, A

    2015-05-11

    The aim of this study was to select putative Terra Maranhão plantain cultivar mutants obtained by gamma radiation, with good agronomic traits and short height. A total of 315 buds were irradiated in vitro with gamma rays in doses of 20 Gy and were subcultivated and evaluated in the field over 2 production cycles. The clones were evaluated to select the best 10% of the plants. Cultivation was undertaken at a spacing of 3 x 4 m, and fertilization was carried out according to the technical recommendations for the crop. A total of 111 irradiated plants and 41 controls were evaluated in the field. Among the irradiated plants selected, genotypes that exhibited reduced height were observed. The genotypes Irra 04, Irra 13, Irra 19, and Irra 21 exhibited a height of 3.6 m, which was below the mean value of the controls selected. Other irradiated genotypes selected such as Irra 14 and Irra 16, with a height of 3.65 m, are promising because, in addition to reduced height, they exhibited good bunch weight and shorter period to flowering in relation to the mean value of the controls, which is a significant factor for the next stages in breeding. These results confirm the possibility of inducing mutations in Terra type banana plants to obtain desirable agronomic traits and short height.

  20. Hydrogel membranes of PVAl/ clay by gamma radiation

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  1. Titanium-Water Thermosyphon Gamma Radiation Effects and Results

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  2. Trypanosoma cruzi Gene Expression in Response to Gamma Radiation

    PubMed Central

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

    2012-01-01

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

  3. Influence on cell proliferation of background radiation or exposure to very low, chronic gamma radiation. [Paramecium tetraurelia; Synechococcus lividus

    SciTech Connect

    Planel, H.; Soleilhavoup, J.P.; Tixador, R.; Richoilley, G.; Conter, A.; Croute, F.; Caratero, C.; Gaubin, Y.

    1987-05-01

    Investigations carried out on the protozoan Paramecium tetraurelia and the cyanobacteria Synechococcus lividus, which were shielded against background radiation or exposed to very low doses of gamma radiation, demonstrated that radiation can stimulate the proliferation of these two single-cell organisms. Radiation hormesis depends on internal factors (age of starting cells) and external factors (lighting conditions). The stimulatory effect occurred only in a limited range of doses and disappeared for dose rates higher than 50 mGy/y.

  4. Study on the structure and electrical behaviour of zinc aluminate ceramics irradiated with gamma radiation

    NASA Astrophysics Data System (ADS)

    Abd El All, S.; Fawzy, Y. H. A.; Radwan, R. M.

    2007-09-01

    The preparation process of zinc aluminate (ZnAl2 O4) ceramic powder, as well as the sintering temperature have been consequently governed using scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. A broad exothermic peak in the range 223-310 °C is observed due to the crystallization of ZnAl2O4 powder. Then the final resultant powder was irradiated with gamma rays at different doses from 30 to 150 kGy. The effect of gamma irradiation on the structure and the electrical behaviour of ZnAl2O4 ceramics has been obtained. The induced changes in the structure have been studied via SEM, XRD and FTIR spectrometers. The obtained results reveal no changes in the spinel phase of ZnAl2O4, while some displacements of the constituent individual atoms for the irradiated samples are observed. The I-V characteristic curves and the dielectric properties of the prepared ceramic powder have been measured for unirradiated and irradiated samples. These curves exhibit nonlinearity of this type of ceramics, where the dc current gradually increases with the increase in the dose. The irradiation of ZnAl2O4 with gamma radiation was found to increase the nonlinearity of the I-V curves. The dielectric constant and loss were found to decrease as the dose increases. Therefore, the irradiation of ZnAl2O4 with gamma rays can improve its utility as an electronic protector in electrical circuits against sudden overvoltage.

  5. Effects of Dietary Iron and Gamma Radiation on the Rat Retina

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    A health risk of concern for NASA relates to radiation exposure and its synergistic effects with other space environmental factors, includi ng nutritional status of the crew. Astronauts consume almost three times the recommended daily allowance of iron due to the use of fortifie d foods aboard the International Space Station, with iron intake occa sionally exceeding six times the recommended values. Recently, NASA has become concerned with visual changes associated with spaceflight, a nd research is being conducted to elucidate the etiology of eye structure alterations in the spaceflight environment. Terrestrially, iron o verload is also associated with certain optic neuropathies. In additi on, due to its role in Fenton reactions, iron can potentiate oxidative stress, which is a recognized cause of cataract formation. As part o f a study investigating the combined effects of radiation exposure an d iron overload on multiple physiological systems, we focused on defining the effects of both treatments on eye biology. In this study, 12- week-old Sprague-Dawley rats were assigned to one of four experimental groups: normal iron/no radiation (Control/Sham), high iron/no radiat ion (Fe/Sham), normal iron/gamma radiation (3 Gy cumulative dose, fra ctionated at 0.375 Gy/d every other day for 16 d) (Control/Rad), and high iron/gamma radiation (Fe/Rad). Oxidative stress-induced DNA damag e, measured as concentration of the marker 8-hydroxy-2'-deoxyguanosine (8OHdG) in eye retinal tissue by enzyme-immunoanalysis did not show significant changes among treatments. However, there was an overall i ncrease in 8OHdG immunostaining density in retina sections due to radiation exposure (P = 0.05). Increased dietary iron and radiation expos ure had an interactive effect (P = 0.02) on 8OHdG immunostaining of t he retinal ganglion cell layer with iron diet increasing the signal in the group not exposed to radiation (P = 0.05). qPCR gene expression profiling of relevant target genes

  6. Protective effects of erdosteine against nephrotoxicity caused by gamma radiation in male albino rats.

    PubMed

    Elkady, A A; Ibrahim, I M

    2016-01-01

    The aim of this study was focused on investigating the possible protective effect of erdosteine against gamma radiation-induced renal lesions in male albino rats. Twenty-eight albino rats were divided into four equal groups as follows: control group, irradiated group (animals subjected to whole-body gamma irradiation at a dose of 5 Gy), treated group (each rat received 100 mg/kg body weight once daily, orally by gastric tube, erdosteine for 1 week), and treated irradiated group (each rat received 100 mg/kg body weight once daily, orally by gastric tube, erdosteine for 1 week, then exposed to whole-body gamma irradiation at a dose of 5 Gy). The results revealed that the administration of erdosteine to rats before irradiation significantly ameliorated the changes occurred in kidney function (creatinine and urea) compared with irradiated group. Also the changes in serum tumor necrosis factor α, interleukin 1β, and interleukin 6 activities were markedly improved compared with the corresponding values of irradiated group. Kidney catalase and glutathione peroxidase (GPx) activities and reduced glutathione concentration showed approximately normal level when compared with the irradiated group. The histopathological results showed distinctive pattern of renal lesions in irradiated group, while in treated irradiated group the renal tissues showed relatively well-preserved architecture. Erdosteine acts in the kidney as a potent scavenger of free radicals to prevent or ameliorate the toxic effects of gamma irradiation as shown in the biochemical and histopathological changes and might provide substantial protection against radiation-induced inflammatory damage.

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

  8. Measurement of background gamma radiation in the northern Marshall Islands.

    PubMed

    Bordner, Autumn S; Crosswell, Danielle A; Katz, Ainsley O; Shah, Jill T; Zhang, Catherine R; Nikolic-Hughes, Ivana; Hughes, Emlyn W; Ruderman, Malvin A

    2016-06-21

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of (137)Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered.

  9. Measurement of background gamma radiation in the northern Marshall Islands

    PubMed Central

    Bordner, Autumn S.; Crosswell, Danielle A.; Katz, Ainsley O.; Shah, Jill T.; Zhang, Catherine R.; Nikolic-Hughes, Ivana; Hughes, Emlyn W.; Ruderman, Malvin A.

    2016-01-01

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of 137Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <<0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered. PMID:27274073

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

    NASA Technical Reports Server (NTRS)

    Dermer, C. D.

    1986-01-01

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

  11. Transcription profile of DNA damage response genes at G₀ lymphocytes exposed to gamma radiation.

    PubMed

    Saini, Divyalakshmi; Shelke, Shridevi; Mani Vannan, A; Toprani, Sneh; Jain, Vinay; Das, Birajalaxmi; Seshadri, M

    2012-05-01

    Ionizing radiation induces a plethora of DNA damages in human cells which may alter the level of mRNA expression. We have analyzed mRNA expression profile of DNA damage response genes involved in G(0)/G(1) check point pathway in whole blood to assess their radio-adaptive response, if any, to gamma radiation. Blood samples were collected from twenty-five random, normal, and healthy male donors with written informed consent and irradiated at doses between 0.1 and 2.0 Gy (0.7 Gy/min). DNA strand breaks were studied using comet assay, whereas DNA double-strand breaks were visualized using γH2AX as a biomarker. Dose response if any, at transcriptional level was studied for all these dose groups at 1 and 5-h post-irradiation. Adaptive response at transcriptional level was studied at three different priming doses (0.1, 0.3, and 0.6 Gy) separately followed by a challenging dose of 2.0 Gy after 4 h. For both the experiments, total RNA was isolated from PBMCs obtained from irradiated whole blood and reverse transcribed to cDNA. The level of mRNA expression of ATM, ATR, GADD45A, CDKN1A, P53, CDK2, MDM2, and Cyclin E was studied using real-time quantitative PCR. A significant dose-dependant increase in the percentage of DNA damage in tail was observed using comet assay. Similarly, increased number of foci was observed at γH2AX with increasing dose. At transcriptional level, a significant dose-dependent up-regulation at GADD45A, CDKN1A, and P53 genes up to 1.0 Gy was observed at 5-h post-irradiation (P ≤ 0.05). Radio-adaptive response at mRNA expression level was observed at CDK2, Cyclin E, and P53, whereas ATM, ATR, GADD45A, MDM2, ATM, and ATR have not shown any radio-adaptive changes in the expression profile. DNA damage response genes involved in G(0)/G(1) checkpoint pathway has important implications in terms of radiosensitivity in vivo and changes in the transcriptional profile might throw some new insights to understand the mechanism of adaptive response.

  12. Tolerance to Gamma Radiation in the Marine Heterotardigrade, Echiniscoides sigismundi

    PubMed Central

    Hygum, Thomas L.; Andersen, Kasper N.; Clausen, Lykke K. B.; Møbjerg, Nadja

    2016-01-01

    Tardigrades belong to the most radiation tolerant animals on Earth, as documented by a number of studies using both low-LET and high-LET ionizing radiation. Previous studies have focused on semi-terrestrial species, which are also very tolerant to desiccation. The predominant view on the reason for the high radiation tolerance among these semi-terrestrial species is that it relies on molecular mechanisms that evolved as adaptations for surviving dehydration. In this study we report the first study on radiation tolerance in a marine tardigrade, Echiniscoides sigismundi. Adult specimens in the hydrated active state were exposed to doses of gamma radiation from 100 to 5000 Gy. The results showed little effect of radiation at 100 and 500 Gy but a clear decline in activity at 1000 Gy and higher. The highest dose survived was 4000 Gy, at which ca. 8% of the tardigrades were active 7 days after irradiation. LD50 in the first 7 days after irradiation was in the range of 1100–1600 Gy. Compared to previous studies on radiation tolerance in semi-terrestrial and limnic tardigrades, Echiniscoides sigismundi seems to have a lower tolerance. However, the species still fits into the category of tardigrades that have high tolerance to both desiccation and radiation, supporting the hypothesis that radiation tolerance is a by-product of adaptive mechanisms to survive desiccation. More studies on radiation tolerance in tardigrade species adapted to permanently wet conditions, both marine and freshwater, are needed to obtain a more comprehensive picture of the patterns of radiation tolerance. PMID:27997621

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

    NASA Astrophysics Data System (ADS)

    Singh, Baljit; Sharma, Vikrant

    2013-11-01

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

  14. Shelf life of ground beef patties treated by gamma radiation.

    PubMed

    Roberts, W T; Weese, J O

    1998-10-01

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

  15. Disinfection of domestic effluents by gamma radiation: effects on the inactivation of Ascaris lumbricoides eggs.

    PubMed

    de Souza, Gloria S M B; Rodrigues, Ludmila A; de Oliveira, Warllem J; Chernicharo, Carlos A L; Guimarães, Marcos P; Massara, Cristiano L; Grossi, Pablo A

    2011-11-01

    This work investigated the inactivation of Ascaris lumbricoides eggs in domestic effluents by gamma radiation from a (60)Co source. Domestic wastewater was treated in a compact demo-scale system consisting of a UASB reactor and a trickling filter; treatment was carried out at the Center for Research and Training on Sanitation (CePTS), Federal University of Minas Gerais, in Belo Horizonte-MG, Brazil. One-liter of treated wastewater samples was artificially contaminated with an average of 1000 non-embryonated Ascaris lumbricoides eggs from human feces; samples were then irradiated in a multiple-purpose irradiator at different doses (0.5-5 kGy). Eggs were recovered from the wastewater and the viability of these irradiated eggs was evaluated; the description of the egg developmental phases with each dose of gamma radiation was recorded. Radiation doses of 3.5 kGy effectively disinfected effluents with lower concentrations of A. lumbricoides eggs; higher radiation doses of 5 kGy were necessary to disinfect effluents with higher eggs concentrations.

  16. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    SciTech Connect

    Paulus, Wilfred; Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Bakar, Maria Abu; Yusoff, Wan Yusmawati Wan

    2015-09-25

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 ± 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 ± 0.0210 GPa and 0.1631 ± 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 ± 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  17. Enhancement of ZnO-rGO nanocomposite thin films by gamma radiation for E. coli sensor

    NASA Astrophysics Data System (ADS)

    Noor Azmy, Noor Azwen; A. Bakar, Ahmad Ashrif; Arsad, Norhana; Idris, Sarada; Mohmad, Abdul Rahman; Abdul Hamid, Aidil

    2017-01-01

    The fabricated E. coli sensor of ZnO-rGO nanocomposite thin films by gamma radiation was investigated. Nanocomposite films were prepared via sol-gel method and were irradiated at 10 kGy at room temperature. The surface characteristic of as-prepared samples have been characterized by x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The proposed structure shows that exposed gamma radiation may change the microstructure of the films occurs as a result of their flexible structure. Uv-vis spectra of nanocomposite were studied to investigate the optical behavior of ZnO-rGO films and the optical energy band gap and Urbach energy were found to be gamma dose dependent. The sensing properties were identified by measuring the changes of conductivity of film using I-V measurement. Upon exposure to E. coli, the radiated ZnO-rGO films (1.00 vol% GO) exhibited higher sensitivity, as much as 4.62 × 10-3, than un-radiated films, 1.04 × 10-3. This enhancement of the I-V response was attributed to a positive influence of the gamma radiation in these films. The results prove that our ZnO-rGO nanocomposites thin films by gamma radiation demonstrate a strong performance for the detection of microbiological organisms in water.

  18. Orchid flowers tolerance to gamma-radiation

    NASA Astrophysics Data System (ADS)

    Kikuchi, Olivia Kimiko

    2000-03-01

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

  19. Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  20. Gamma radiation effects on the dynamic fatigue measurements of glass discs

    NASA Technical Reports Server (NTRS)

    Ananaba, T. O. J.; Kinser, D. L.

    1985-01-01

    Circular specimens of low iron soda lime silicate glass were blasted with grit after having a circular notch etched into their centers. After separation into two groups, one group was exposed to gamma radiation. The fracture strengths of all samples were then tested by the biaxial technique, i.e., specimens were balanced on three balls and loaded in the center by a piston. The irradiated samples had received a 140,000 Gy dose from a Co-60 source. An enhanced interaction between the ambient moisture and the grit-blasted central notch was observed in the irradiated samples, which displayed accelerated corrosion.

  1. Evaluation of the in vivo genotoxic effects of gamma radiation on the peripheral blood leukocytes of head and neck cancer patients undergoing radiotherapy.

    PubMed

    Kadam, Samit B; Shyama, Soorambail K; Almeida, Valentine G

    2013-04-15

    The present study aimed to evaluate the genotoxic effects of ionizing radiation on non-target cells of Head and Neck Squamous Cell Carcinoma (HNSCC) patients exposed to various cumulative doses of gamma rays during radiotherapy. The ten patients (P1-P10) were treated with cobalt 60 gamma radiation (External Beam Radiotherapy) for a period of five to six weeks with a daily fraction of 2Gy for 5 days each week. The genotoxic effects of radiation (single strand breaks - SSBs) in these patients were analyzed using the alkaline single cell gel electrophoresis (SCGE) technique, with the Olive Tail Moment (OTM) as the critical parameter. A sample of each patient's peripheral blood before starting with radiotherapy (pre-therapy) served as the control, and blood collected at weekly time intervals during the course of the radiotherapy served as treated (10, 20, 30, 40, 50 and 60Gy) samples. In vivo radiosensitivity of these patients, as indicated by SSB's after the cumulative radiation doses at the various times, was assessed using Student's t-test. Significant DNA damage relative to the individual patient's pre-therapy baseline data was observed in all patients. Inter-individual variation of the genotoxic effects was analyzed using two-way ANOVA. The correlation between doses for the means of smoker and non-smoker patients was calculated using the Pearson test. The results of this study may indicate the need to reduce the daily radiotherapy dose further to prevent genotoxic effects on non-target cells, thus improving safety. Furthermore, these results may indicate that the estimation of DNA damage following exposure to a gamma radiation, as measured by the comet assay in whole blood leukocytes, can be used to screen human populations for radiation-induced genetic damage at the molecular level.

  2. Sewage sludge pasteurization by gamma radiation: Financial viability case studies

    NASA Astrophysics Data System (ADS)

    Swinwood, Jean F.; Kotler, Jiri

    This paper examines the financial viability of sewage sludge pasteurization by gamma radiation, by examining the following three North American scenarios: 1) Small volume sewage treatment plant experiencing high sludge disposal costs. 2) Large volume sewage treatment plant experiencing low sludge disposal costs. 3) Large volume sewage treatment plant experiencing high sludge disposal costs.

  3. The effect of gamma radiation on recombination frequency in Caenorhabditis elegans.

    PubMed

    Kim, J S; Rose, A M

    1987-06-01

    We have studied the effect of gamma radiation on recombination frequency for intervals across the cluster of linkage group I in Caenorhabditis elegans. Recombination frequency increased approximately twofold across the dpy-5-unc-13 interval after treatment with 2000 rads (1 rad = 10 mGy) of cobalt 60 gamma radiation. Several factors affecting the magnitude of the increase have been characterized. Recombination frequency increased more with higher doses of radiation. However, the increase in recombination frequency with increasing dose was accompanied by a reduced average number of progeny from radiation-treated individuals. The amount of the increase was affected by meiotic stage, age at the time of treatment (premeiotic), and radiation dose. The increase in recombination was detectable in the B brood and remained elevated for the remainder of egg production. X-chromosome nondisjunction was also increased by radiation treatment. A high frequency of the recombinant progeny produced with radiation treatment were sterile unlike their nonrecombinant siblings. When parameters affecting recombination frequency are held constant during treatment, chromosomal regions of high gene density on the meiotic map increased more (fourfold) than an adjacent region of low gene density (no increase). The greatest increase was across the dpy-14-unc-13 interval near the center of the gene cluster. These results may suggest that the physical length of DNA per map unit is greater within the cluster than outside.

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

    NASA Astrophysics Data System (ADS)

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

    1991-04-01

    A new radiation-sensitive imaging material, called GafChromic™ Dosimetry Media, offers advances in high-dose radiation dosimetry and high-resolution radiography for gamma radiation and electrons. The potential uses in radiation processing, radiation sterilization of medical devices, population control of insects by irradiation, food irradiation, blood irradiation for organ-transplant immuno-suppression, clinical radiography, and industrial radiography have led to the present sensitometric study over the breadth of the wide dynamic range of this new routine detector and imaging material, namely, absorbed doses from 10 Gy to 5 × 10 4 Gy. The thin-coated film is colorless before irradiation, and registers a deep-blue image upon irradiation, with two absorption bands at about 650 nm (major band) and 600 nm (minor band). The response to electrons, in terms of increase in absorbance per unit absorbed dose, is the same as that to gamma radiation within the estimated uncertainty of the measurements (± 5%, 95% confidence level). The spatial resolving power is > 1200 lines/mm. After the first 24 hours, the image is stable over many months (within ± 5% in absorbance), however, the system should be irradiated and analyzed at approximately the temperatures used during calibration, because of temperature dependence during irradiation and readout, and temperatures greater than 55°C should be avoided.

  5. Tracking Human Adenovirus Inactivation by Gamma Radiation under Different Environmental Conditions

    PubMed Central

    Pimenta, Andreia I.; Guerreiro, Duarte; Madureira, Joana; Margaça, Fernanda M. A.

    2016-01-01

    ABSTRACT Adenovirus is the most prevalent enteric virus in waters worldwide due to its environmental stability, which leads to public health concerns. Mitigation strategies are therefore required. The aim of this study was to assess the inactivation of human adenovirus type 5 (HAdV-5) by gamma radiation in aqueous environments. Various substrates with different organic loads, including domestic wastewater, were inoculated with HAdV-5 either individually or in a viral pool (with murine norovirus type 1 [MNV-1]) and were irradiated in a Cobalt-60 irradiator at several gamma radiation doses (0.9 to 10.8 kGy). The infectivity of viral particles, before and after irradiation, was tested by plaque assay using A549 cells. D10 values (dose required to inactivate 90% of a population or the dose of irradiation needed to produce a 1 log10 reduction in the population) were estimated for each substrate based on virus infectivity inactivation exponential kinetics. The capability of two detection methods, nested PCR and enzyme-linked immunosorbent assay (ELISA), to track inactivated viral particles was also assessed. After irradiation at 3.5 kGy, a reduction of the HAdV-5 titer of 4 log PFU/ml on substrates with lower organic loads was obtained, but in highly organic matrixes, the virus titer reduction was only 1 log PFU/ml. The D10 values of HAdV-5 in high organic substrates were significantly higher than in water suspensions. The obtained results point out some discrepancies between nested PCR, ELISA, and plaque assay on the assessments of HAdV-5 inactivation. These results suggest that the inactivation of HAdV-5 by gamma radiation, in aqueous environments, is significantly affected by substrate composition. This study highlights the virucidal potential of gamma radiation that may be used as a disinfection treatment for sustainable water supplies. IMPORTANCE Human adenovirus (HAdV) is the most prevalent of the enteric viruses in environmental waters worldwide. The purposes of

  6. Gamma radiation effects on silicon photonic waveguides.

    PubMed

    Grillanda, Stefano; Singh, Vivek; Raghunathan, Vivek; Morichetti, Francesco; Melloni, Andrea; Kimerling, Lionel; Agarwal, Anuradha M

    2016-07-01

    To support the use of integrated photonics in harsh environments, such as outer space, the hardness threshold to high-energy radiation must be established. Here, we investigate the effects of gamma (γ) rays, with energy in the MeV-range, on silicon photonic waveguides. By irradiation of high-quality factor amorphous silicon core resonators, we measure the impact of γ rays on the materials incorporated in our waveguide system, namely amorphous silicon, silicon dioxide, and polymer. While we show the robustness of amorphous silicon and silicon dioxide up to an absorbed dose of 15 Mrad, more than 100× higher than previous reports on crystalline silicon, polymer materials exhibit changes with doses as low as 1 Mrad.

  7. Gamma radiation transmission along the multibend mazes.

    PubMed

    Kim, Sangrok

    2016-08-01

    Installing a maze on the corridor reduces much shielding materials in shielding door at the end of the pathway. In this study, gamma transmission was measured along single-, double-, and triple-bend mazes, which were applied to nondestructive test workplace by Monte Carlo method. In the facility using (192)Ir 1.85TBq, the lengths of corridors to reduce the effective dose under the limitation without shielding door were 10 and 6m in double- and triple-bend mazes, respectively.

  8. Phosphate Glass Gamma-Radiation Dosimeter

    DTIC Science & Technology

    1952-11-30

    phosphate i 3 5 6 1 8 10 10 11 11 12 12 i3 lit it Hi 15 15 15 15 15 16 16 17 1? 3 18 33 id 39 19 39 29 39 20...INFORMATION — RESTRICTED wmmtm POLAROID CORPORATION —RESEARCH DEPARTMENT RESTRICTED -10- Seotion 3 -A. Properties of Silver Phosphate Glass A...Dose Fluorescence* fi it i. - 4 " J" S®,’ As indicated above, when the glass has been exposed to 100 v of 1» 3

  9. Novel synthetic (S,S) and (R,R)-secoisolariciresinol diglucosides (SDGs) protect naked plasmid and genomic DNA From gamma radiation damage.

    PubMed

    Mishra, Om P; Pietrofesa, Ralph; Christofidou-Solomidou, Melpo

    2014-07-01

    Secoisolariciresinol diglucoside (SDG) is the major lignan in wholegrain flaxseed. However, extraction methods are complex and are associated with low yield and high costs. Using a novel synthetic pathway, our group succeeded in chemically synthesizing SDG (S,S and R,R enantiomers), which faithfully recapitulates the properties of their natural counterparts, possessing strong antioxidant and free radical scavenging properties. This study further extends initial findings by now investigating the DNA-radioprotective properties of the synthetic SDG enantiomers compared to the commercial SDG. DNA radioprotection was assessed by cell-free systems such as: (a) plasmid relaxation assay to determine the extent of the supercoiled (SC) converted to open-circular (OC) plasmid DNA (pBR322) after exposure of the plasmid to gamma radiation; and (b) determining the extent of genomic DNA fragmentation. Exposure of plasmid DNA to 25 Gy of γ radiation resulted in decreased supercoiled form and increased open-circular form, indicating radiation-induced DNA damage. Synthetic SDG (S,S) and SDG (R,R), and commercial SDG at concentrations of 25-250 μM significantly and equipotently reduced the radiation-induced supercoiled to open-circular plasmid DNA in a dose-dependent conversion. In addition, exposure of calf thymus DNA to 50 Gy of gamma radiation resulted in DNA fragments of low-molecular weight (<6,000 bps), which was prevented in a dose-dependence manner by all synthetic and natural SDG enantomers, at concentrations as low as 0.5 μM. These novel results demonstrated that synthetic SDG (S,S) and SDG (R,R) isomers and commercial SDG possess DNA-radioprotective properties. Such properties along with their antioxidant and free radical scavenging activity, reported earlier, suggest that SDGs are promising candidates for radioprotection for normal tissue damage as a result of accidental exposure during radiation therapy for cancer treatment.

  10. Carbon Nanotubes Synthesis Through Gamma Radiation

    NASA Astrophysics Data System (ADS)

    Tirado, Pablo; Garcia, Rafael; Montes, Jorge; Melendrez, Rodrigo; Barboza, Marcelino; Contreras, Oscar

    2015-03-01

    Carbon nanotubes show a great potential of applications since there discovery by Iijima in 1991[1] due to their numerous physical-chemical properties such as their high weight to strength relationship, which make them ideal to use in high resistance compound materials, and in many other applications[2] In this work, a novel method for the synthesis of carbon nanotubes is presented, starting from an ultra-thin sheet of graphite synthesized by the chemical vapor decomposition technique (CVD), using ultra high purity methane and hydrogen at 1200°C in a horizontal quartz reactor. For the synthesis of carbon nanotubes, the graphite sheets were exposed to different doses of radiation, with the objective of breaking the graphite bonds and form carbon nanotubes; a Gammacell equipment model 220 Excel was used for the purpose, which counts with a radiation source of cobalt 60, and a current radiation rate of 0.9 Gy/seconds. The time of exposure to radiation was varied in each sample, according to the desired dose of radiation in each case, afterwards the samples were characterized using the Raman spectroscopy and TEM microscopy techniques with the objective of observing the kind of nanotubes formed, their morphology and their number of defects. Results will be shown during the poster session.

  11. Gamma radiation resistance of spin Seebeck devices

    NASA Astrophysics Data System (ADS)

    Yagmur, A.; Uchida, K.; Ihara, K.; Ioka, I.; Kikkawa, T.; Ono, M.; Endo, J.; Kashiwagi, K.; Nakashima, T.; Kirihara, A.; Ishida, M.; Saitoh, E.

    2016-12-01

    Thermoelectric devices based on the spin Seebeck effect (SSE) were irradiated with gamma (γ) rays with the total dose of around 3 × 105 Gy in order to investigate the γ-radiation resistance of the devices. To demonstrate this, Pt/Ni0.2Zn0.3Fe2.5O4/Glass and Pt/Bi0.1Y2.9Fe5O12/Gd3Ga5O12 SSE devices were used. We confirmed that the thermoelectric, magnetic, and structural properties of the SSE devices are not affected by the γ-ray irradiation. This result demonstrates that SSE devices are applicable to thermoelectric generation even in high radiation environments.

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

    SciTech Connect

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

    1985-11-01

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

  13. Rhizophagus irregularis MUCL 41833 can colonize and improve P uptake of Plantago lanceolata after exposure to ionizing gamma radiation in root organ culture.

    PubMed

    Kothamasi, David; Wannijn, Jean; van Hees, May; Nauts, Robin; van Gompel, Axel; Vanhoudt, Nathalie; Cranenbrouck, Sylvie; Declerck, Stéphane; Vandenhove, Hildegarde

    2016-04-01

    Long-lived radionuclides such as (90)Sr and (137)Cs can be naturally or accidentally deposited in the upper soil layers where they emit β/γ radiation. Previous studies have shown that arbuscular mycorrhizal fungi (AMF) can accumulate and transfer radionuclides from soil to plant, but there have been no studies on the direct impact of ionizing radiation on AMF. In this study, root organ cultures of the AMF Rhizophagus irregularis MUCL 41833 were exposed to 15.37, 30.35, and 113.03 Gy gamma radiation from a (137)Cs source. Exposed spores were subsequently inoculated to Plantago lanceolata seedlings in pots, and root colonization and P uptake evaluated. P. lanceolata seedlings inoculated with non-irradiated AMF spores or with spores irradiated with up to 30.35 Gy gamma radiation had similar levels of root colonization. Spores irradiated with 113.03 Gy gamma radiation failed to colonize P. lanceolata roots. P content of plants inoculated with non-irradiated spores or of plants inoculated with spores irradiated with up to 30.35 Gy gamma radiation was higher than in non-mycorrhizal plants or plants inoculated with spores irradiated with 113.03 Gy gamma radiation. These results demonstrate that spores of R. irregularis MUCL 41833 are tolerant to chronic ionizing radiation at high doses.

  14. Reusable shielding material for neutron- and gamma-radiation

    NASA Astrophysics Data System (ADS)

    Calzada, Elbio; Grünauer, Florian; Schillinger, Burkhard; Türck, Harald

    2011-09-01

    At neutron research facilities all around the world radiation shieldings are applied to reduce the background of neutron and gamma radiation as far as possible in order to perform high quality measurements and to fulfill the radiation protection requirements. The current approach with cement-based compounds has a number of shortcomings: "Heavy concrete" contains a high amount of elements, which are not desired to obtain a high attenuation of neutron and/or gamma radiation (e.g. calcium, carbon, oxygen, silicon and aluminum). A shielding material with a high density of desired nuclei such as iron, hydrogen and boron was developed for the redesign of the neutron radiography facility ANTARES at beam tube 4 (located at a cold neutron source) of FRM-II. The composition of the material was optimized by help of the Monte Carlo code MCNP5. With this shielding material a considerable higher attenuation of background radiation can be obtained compared to usual heavy concretes.

  15. Designing Equipment for Use in Gamma Radiation Environments

    SciTech Connect

    Vandergriff, K.U.

    1990-01-01

    High levels of gamma radiation are known to cause degradation in a variety of materials and components. When designing systems to operate in a high radiation environment, special precautions and procedures should be followed. This report (1) outlines steps that should be followed in designing equipment and (2) explains the general effects of radiation on various engineering materials and components. Much information exists in the literature on radiation effects upon materials. However, very little information is available to give the designer a step-by-step process for designing systems that will be subject to high levels of gamma radiation, such as those found in a nuclear fuel reprocessing facility. In this report, many radiation effect references are relied upon to aid in the design of components and systems.

  16. Gamma radiation background measurements from Spacelab 2

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  17. Rheology of Indian Honey: Effect of Temperature and Gamma Radiation.

    PubMed

    Saxena, Sudhanshu; Panicker, Lata; Gautam, Satyendra

    2014-01-01

    Honey brands commonly available in Indian market were characterized for their rheological and thermal properties. Viscosity of all the honey samples belonging to different commercial brands was found to decrease with increase in temperature (5-40°C) and their sensitivity towards temperature varied significantly as explained by calculating activation energy based on Arrhenius model and ranged from 54.0 to 89.0 kJ/mol. However, shear rate was not found to alter the viscosity of honey indicating their Newtonian character and the shear stress varied linearly with shear rate for all honey samples. Honey is known to contain pathogenic microbial spores and in our earlier study gamma radiation was found to be effective in achieving microbial decontamination of honey. The effect of gamma radiation (5-15 kGy) on rheological properties of honey was assessed, and it was found to remain unchanged upon radiation treatment. The glass transition temperatures (T g ) of these honey analyzed by differential scanning calorimetry varied from -44.1 to -54.1°C and remained unchanged upon gamma radiation treatment. The results provide information about some key physical properties of commercial Indian honey. Radiation treatment which is useful for ensuring microbial safety of honey does not alter these properties.

  18. Preparation of a polybutadiene stationary phase immobilized by gamma radiation for reversed-phase high-performance liquid chromatography.

    PubMed

    Lopes, Nilva P; Collins, Kenneth E; Jardim, Isabel C S F

    2003-02-14

    Polybutadiene (PBD) has been immobilized on HPLC silica by gamma radiation doses in the range from 5 to 180 kGy. Columns prepared from these reversed-phase materials, as well as from similar non-irradiated materials, were tested with standard sample mixtures and characterized by elemental analysis (% C) and infrared spectroscopy. A low dose of 5 kGy is sufficient to produce a layer of immobilized PBD which functions as an efficient and stable stationary phase. Higher doses give thicker immobilized layers having less favorable chromatographic properties.

  19. Gamma Radiation Aging Study of a Dow Corning SE 1700 Porous Structure Made by Direct Ink Writing

    SciTech Connect

    Small, Ward; Alviso, Cindy T.; Metz, Tom R.

    2015-11-13

    Dow Corning SE 1700 (reinforced polydimethylsiloxane) porous structures were made by direct ink writing (DIW). The specimens (~50% porosity) were subjected to a compressive strain of ~25% while exposed to a gamma radiation dose of 1, 5, or 10 Mrad under vacuum. Compression set and load retention of the aged specimens were measured after a ~24 h relaxation period. Compression set (relative to deflection) increased with radiation dose: 11, 35, and 51% after 1, 5, and 10 Mrad, respectively. Load retention was 96-97% for the doses tested. The SE 1700 compared favorably to M9763 cellular silicone tested under the same conditions.

  20. A Systems Genetic Approach to Identify Low Dose Radiation-Induced Lymphoma Susceptibility/DOE2013FinalReport

    SciTech Connect

    Balmain, Allan; Song, Ihn Young

    2013-05-15

    The ultimate goal of this project is to identify the combinations of genetic variants that confer an individual's susceptibility to the effects of low dose (0.1 Gy) gamma-radiation, in particular with regard to tumor development. In contrast to the known effects of high dose radiation in cancer induction, the responses to low dose radiation (defined as 0.1 Gy or less) are much less well understood, and have been proposed to involve a protective anti-tumor effect in some in vivo scientific models. These conflicting results confound attempts to develop predictive models of the risk of exposure to low dose radiation, particularly when combined with the strong effects of inherited genetic variants on both radiation effects and cancer susceptibility. We have used a Systems Genetics approach in mice that combines genetic background analysis with responses to low and high dose radiation, in order to develop insights that will allow us to reconcile these disparate observations. Using this comprehensive approach we have analyzed normal tissue gene expression (in this case the skin and thymus), together with the changes that take place in this gene expression architecture a) in response to low or high- dose radiation and b) during tumor development. Additionally, we have demonstrated that using our expression analysis approach in our genetically heterogeneous/defined radiation-induced tumor mouse models can uniquely identify genes and pathways relevant to human T-ALL, and uncover interactions between common genetic variants of genes which may lead to tumor susceptibility.

  1. Oxidation of naringenin by gamma-radiation

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

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

  2. Determination of carbamate and organophosphorus pesticides in vegetable samples and the efficiency of gamma-radiation in their removal.

    PubMed

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  5. [The of gamma-radiation for induction of apomixis in sea-buckthorn (Hippophaë rhamnoides L.)].

    PubMed

    Todya, V A; Chankseliani, Z Zh; Mchedlishvili, M V

    2006-01-01

    The results of studying of the induced apomixis in pollen of sea-buckthorn irradiated by the 60Co gamma-Radiation are considered. Was established that the most effective dose for pollination of the experimental plants is 50 k Gy. In total, from 46 seedlings 19 cases of apomictic origin were revealed, 7 individuals were found to be haploid (n = = 12) and 19 ones were diploid (2n = 24) of maternal origin. Was supposed that apomictic plants (19 seedlings) have parthenogenetic origin. The reason for such conclusion is that the irradiated anomalous pollen tubes despite not having spermia, are entering embryo sac and stimulate the development of apomictic embryo from non-fertilized female gametes. Apparently, pollen tubes cause the induction of DNA replication in the ovules and the development of parthenogenetic plants. Consequently, the described method can be used for the regulation of parthenogenesis in sea-buckthorn to change natural ratio (1 : 1) of male to female plants in desirable quantity.

  6. Appraisal of marigold flower based lutein as natural colourant for textile dyeing under the influence of gamma radiations

    NASA Astrophysics Data System (ADS)

    Adeel, Shahid; Gulzar, Tahsin; Azeem, Muhammad; Fazal-ur-Rehman; Saeed, Muhammad; Hanif, Iram; Iqbal, Naeem

    2017-01-01

    Maintaining colour strength and fastness of the fabrics dyed with natural colourants had been the major constraint of utilizing plant based dyes in modern textile practices. The present study was concerned with the extraction of lutein dye from marigold (Tagetes erecta L.) flowers and role of gamma radiation in improving colour strength and fastness characteristics of the extracted dye. The investigation of dyed fabric in spectraflash showed that gamma ray treatment of 30 kGy was the optimum absorbed dose for surface modification to improve its dye uptake ability. Good colour strength was obtained when irradiated cotton (RC, 30 kGy) was dyed with extract of radiated marigold flower powder (RP) at 70 °C for 85 min, keeping M:L of 1:50 using dye bath of pH 5.0. The results from mordanting experiments revealed that 7% of tannic acid as pre-mordant and 5% of Cu as post-mordant were the best treatments to improve colour strength. It was found that gamma ray induced extraction of lutein from marigold flowers had a potential to be utilized as natural dyes in textile sector to produce yellowish green shades.

  7. Monte Carlo Calculations for Neutron and Gamma Radiation Fields on a Fast Neutron Irradiation Device

    NASA Astrophysics Data System (ADS)

    Vieira, A.; Ramalho, A.; Gonçalves, I. C.; Fernandes, A.; Barradas, N.; Marques, J. G.; Prata, J.; Chaussy, Ch.

    We used the Monte Carlo program MCNP to calculate the neutron and gamma fluxes on a fast neutron irradiation facility being installed on the Portuguese Research Reactor (RPI). The purpose of this facility is to provide a fast neutron beam for irradiation of electronic circuits. The gamma dose should be minimized. This is achieved by placing a lead shield preceded by a thin layer of boral. A fast neutron flux of the order of 109 n/cm2s is expected at the exit of the tube, while the gamma radiation is kept below 20 Gy/h. We will present results of the neutron and gamma doses for several locations along the tube and different thickness of the lead shield. We found that the neutron beam is very collimated at the end of the tube with a dominant component on the fast region.

  8. Proton and Gamma Radiation Effects in Undoped, Single-doped and co-doped YLiF4 and LuLiF4

    NASA Technical Reports Server (NTRS)

    Lee, Hyung; Bai, Yingxin; Yu, Kirong; Singh, U.

    2009-01-01

    Proton and gamma radiation effects in various YLiF4 and LuLiF4 crystals have been investigated. The radiation induced color centers compared with six different kinds of crystal samples in ranges up to 200 krads and 200 MeV. The radiation induced absorption coefficients are strongly dependent on polarization and concentration of rare-earth ions.

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

    SciTech Connect

    Sui, Meihua; Fan Weimin . E-mail: fanw@musc.edu

    2005-03-15

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

  10. Paeoniflorin protects human EA.hy926 endothelial cells against gamma-radiation induced oxidative injury by activating the NF-E2-related factor 2/heme oxygenase-1 pathway.

    PubMed

    Yu, Jing; Zhu, Xiaoyun; Qi, Xin; Che, Juanjuan; Cao, Bangwei

    2013-04-26

    Pulmonary endothelial cells have been demonstrated to have a critical role in the pathogenesis of radiation-induced lung injury. Our preliminary experiments indicated that paeoniflorin protected human EA.hy926 endothelial cells from radiation-induced oxidative injury. This study was designed to confirm the protective effect of paeoniflorin against radiation-induced endothelial cellular damage and to elucidate the underlying mechanisms. Preincubation of EA.hy926 cells with paeoniflorin before γ-radiation resulted in significant inhibition of apoptosis, a decrease in mitochondrial membrane potential and enhanced cell viability. In particular, we showed that paeoniflorin significantly reduced the formation of intracellular reactive oxygen species (ROS), the level of malondialdehyde (MDA) and lactate dehydrogenase (LDH) leakage, and enhanced production of the endogenous antioxidants, glutathione (GSH) and superoxide dismutase (SOD) in EA.hy926 cells. Treatment of these cells with paeoniflorin significantly induced HO-1 expression. Moreover, paeoniflorin promoted the nuclear translocation of nuclear factor erythroid 2 related factor-2 (Nrf-2). The paeoniflorin-induced HO-1 expression was abrogated by Nrf2 siRNA. Furthermore, inhibition of HO-1 with zinc protoporphyrin IX (ZNPP) significantly reversed the protective effect of paeoniflorin against radiation-induced damage in EA.hy926 cells. Our findings confirmed that paeoniflorin protected EA.hy926 cells against radiation-induced injury through the Nrf2/HO-1 pathway.

  11. Induction of p53 protein by gamma radiation in lymphocyte lines from breast cancer and ataxia telangiectasia patients.

    PubMed Central

    Birrell, G. W.; Ramsay, J. R.

    1995-01-01

    Exposure of human cells to gamma-radiation causes levels of the tumour-suppressor nuclear protein p53 to increase in temporal association with the decrease in replicative DNA synthesis. Cells from patients with the radiosensitive and cancer-prone disease ataxia telangiectasia (AT) exhibit radioresistant DNA synthesis and show a reduced or delayed gamma-radiation-induced increase in p53 protein levels. We have used Western immunoblotting with semiquantitative densitometry to examine the gamma-radiation-induced levels of p53 protein in 57 lymphoblastoid cell lines (LCLs) derived from patients with AT, carriers of the AT gene, breast cancer patients and normal donors. We confirm the previously reported reduced induction in AT homozygote LCLs (n = 8) compared with normal donor LCLs (n = 17, P = 0.01). We report that AT heterozygote LCLs (n = 5) also have a significantly reduced p53 induction when compared with LCLs from normal donors (n = 17, P = 0.02). The response of breast cancer patient cells was not significantly different from normal donor cells but 18% (5/27) had a p53 response in the AT heterozygote range (95% confidence interval) compared with only 6% (1/17) of the normal donor cells. We found no significant correlation between p53 induction and cellular radiosensitivity in LCLs from breast cancer patients. These methods may be useful in identifying individuals at greater risk of the DNA-damaging effects of ionising radiation. Images Figure 2 PMID:7577453

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

    SciTech Connect

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

    2005-08-08

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

  13. Modification of low dose radiation induced radioresistance by 2-deoxy-D-glucose in Saccharomyces cerevisiae: mechanistic aspects.

    PubMed

    Bala, Madhu; Goel, Harish C

    2007-07-01

    Use of 2-deoxy-D-glucose (2-DG) in combination with radiotherapy to radio-sensitize the tumor tissue is undergoing clinical trials. The present study was designed to investigate the effect of 2-DG on radiation induced radioresistance (RIR) in normal cells. The sub-lethal radiation dose to the normal cells at the periphery of target tumor tissue is likely to induce radioresistance and protect the cells from lethal radiation dose. 2-DG, since, enters both normal and tumor cells, this study have clinical relevance. A diploid respiratory proficient strain D7 of S. cerevisiae was chosen as the model system. In comparison to non-pre-irradiated cultures, the cultures that were pre-exposed to low doses of UVC (254 nm) or (60)Co-gamma-radiation, then maintained in phosphate buffer (pH 6.0, 67 mM), containing 10 mM glucose (PBG), for 2-5 h, showed 18-35% higher survivors (CFUs) after subsequent exposure to corresponding radiation at lethal doses suggesting the radiation induced radioresistance (RIR). The RIR, in the absence of 2-DG, was associated with reduced mutagenesis, decreased DNA damage, and enhanced recombinogenesis. Presence of 2-DG in PBG countered the low dose induced increase in survivors and protection to DNA damage. It also increased mutagenesis, altered the recombinogenesis and the expression of rad50 gene. The changes differed quantitatively with the type of radiation and the absorbed dose. These results, since, imply the side effects of 2-DG, it is suggested that new approaches are needed to minimize the retention of 2-DG in normal cells at the time of radiation exposure.

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

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

    SciTech Connect

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

    2004-11-05

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

  16. Retrospective dosimetry after criticality accidents using low-frequency EPR: a study of whole human teeth irradiated in a mixed neutron and gamma-radiation field.

    PubMed

    Zdravkova, M; Crokart, N; Trompier, F; Asselineau, B; Gallez, B; Gaillard-Lecanu, E; Debuyst, R

    2003-08-01

    In the context of accidental or intentional radiation exposures (nuclear terrorism), it is essential to separate rapidly those individuals with substantial exposures from those with exposures that do not constitute an immediate threat to health. Low-frequency electron paramagnetic resonance (EPR) spectroscopy provides the potential advantage of making accurate and sensitive measurements of absorbed radiation dose in teeth without removing the teeth from the potential victims. Up to now, most studies focused on the dose-response curves obtained for gamma radiation. In radiation accidents, however, the contribution of neutrons to the total radiation dose should not be neglected. To determine how neutrons contribute to the apparent dose estimated by EPR dosimetry, extracted whole human teeth were irradiated at the SILENE reactor in a mixed neutron and gamma-radiation field simulating criticality accidents. The teeth were irradiated in free air as well as in a paraffin head phantom. Lead screens were also used to eliminate to a large extent the contribution of the gamma radiation to the dose received by the teeth. The EPR signals, obtained with a low-frequency (1.2 GHz) spectrometer, were compared to dosimetry measurements at the same location. The contribution of neutrons to the EPR dosimetric signal was negligible in the range of 0 to 10 Gy and was rather small (neutron/gamma-ray sensitivity in the range 0-0.2) at higher doses. This indicates that the method essentially provides information on the dose received from the gamma-ray component of the radiation.

  17. Effects of gamma radiation and storage time on the physical, chemical and sensory qualities of ''Georgia Jet'' sweet potatoes

    SciTech Connect

    Yakubu, P.I.

    1986-12-01

    Effect of gamma radiation and storage time on sprouting, rotting, changes in nutritional composition and sensory quality of Georgia Jet Sweet Potatoes were studied. All radiation doses used in the study inhibited sprouting. Sweet potatoes were severely injured at doses of 1.5 and 2.0 kGy and these doses affected their storage life and sensory quality. There was no significant difference in nutrient composition of sweet potatoes irradiated at doses of 0.8, 0.5, 0.1 kGy and the control. A dose of gamma rays of 0.5 kGy and above may not be desirable for sweet potatoes. The optimum dose may lie between 0.5 and 0.1 kGy.

  18. Monitoring precipitation and lightning via changes in atmospheric gamma radiation

    SciTech Connect

    Greenfield, M.B.; Domondon, A.; Tsuchiya, S.; Tomiyama, G.

    2003-08-26

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

  19. Biological wound dressings sterilized with gamma radiation: Mexican clinical experience

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

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

  20. Effects of gamma radiation on nymphal development and reproductive capacity of the large milkweed bug, Oncopeltus fasciatus (Dallas) (Hemiptera - Lygaeidae)

    SciTech Connect

    Moursy, L.E.

    1985-01-01

    Gamma radiation adversely affected important fitness components of Oncopeltus fasciatus, particularly as expressed by nymphal development, subsequent reproductive capacity, mating competitiveness and longevity. Early treated 5th instar nymphs are about 2X more sensitive to gamma radiation than late treated 5th instar nymphs based upon LD50 values. The extremes in sensitivity were 5.01 kilorads (krad) for early treated males and 13.09 krad for females treated late in the 5th instar. Wing deformities resulted from doses in the same range as those for mortality. Fifty percent of early treated males had wing deformities at a dose of 10.81 krad while a dose of 12.5 and 12.89 krad was necessary for 50% wing deformities in males and females, respectively, when treated late in the 5th instar. Fecundity and fertility were affected at lower dosages of radiation than for mortality. The treatment of both sexes produced the greatest effect. Fecundity was reduced by 50% at 1.22 krad, while 50% reduction in fertility occurred at about half that dose, or 0.66 krad. Somewhat greater doses were required when females alone were treated and mated with untreated males. In this case a 50% reduction occurred with 1.87 and 1.07 krad for fecundity and fertility, respectively. When males alone were treated, ED50 values were 2.24 and 1.58 krad for fecundity and fertility, respectively.

  1. Effect of Gamma Radiations on the Quality and Shelf Life of Strawberry Fruit of the Uttrakhand Region

    NASA Astrophysics Data System (ADS)

    Sharma, Prianka; Rastogi, Meetu

    2016-08-01

    Present study was conducted to investigate the effect of gamma radiations on the quality and shelf life of strawberries. The aim of this study was to evaluate gamma radiation doses in range of 0.3- 1.5 kGy. The irradiated strawberries were stored in ambient (temperature 25 +- 2oC, RH 70 %) and refrigerated (3 +-1oC, RH 80%) conditions. In samples treated with dose 1.2-1.5 kGy no decay was recorded up to 9 days of ambient conditions. Under refrigerated conditions, strawberry samples of unirradiated and irradiated in the range of 0.3-0.9 kGy started decaying after 14 days of storage. No decay was observed in the samples treated with 1.2-1.5 kGy up to 28 days of refrigerated storage. Dose of 1.2 kGy was significantly effective in reducing the weight loss and in maintaining the higher overall acceptability under both the storage conditions compared to the other treatments. This dose also proved effective in retention of significantly higher levels of total sugars compared to the other treatments. Thus, it was established that irradiating strawberries with dose of 1.2 kGy can prove beneficial in facilitating the marketing of the fruit to distant places other than the local markets, thereby benefiting the growers.

  2. Lung tumorigenic response of strain A mice exposed to hypoxic cell sensitizers alone and in combination with gamma-radiation

    SciTech Connect

    Mian, T.A.; Theiss, J.C.; Grdina, D.J.

    1983-01-01

    The influence of metronidazole, misonidazole, and desmethylmisonidazole on the induction of lung adenomas in the strain A mouse was examined. Two dose levels of the hypoxic cell sensitizers, 0.2 and 0.6 mg/g, were used either alone or in combination with 900 rads of gamma-radiation in a fractionated dose schedule of twice a week for 3 weeks. In the groups of mice which received hypoxic cell sensitizers only, the prevalence and the mean number of lung tumors per mouse were somewhat increased (p less than 0.10) in the group receiving the higher dose (0.6 mg/g) of misonidazole but was not significantly different from results for the control animals in the other two sensitizer groups. The combination of hypoxic cell sensitizer and radiation did not show any significant enhancement of lung tumor response when compared with the group which received radiation only. The dose of radiation used in this study significantly enhanced lung tumor formation in mice when compared with that in the control group. Thus, under the experimental exposure conditions used in this investigation, which were somewhat similar to the exposure conditions occurring in clinical treatment, each of the hypoxic cell sensitizers tested failed to sensitize significantly the mice to the carcinogenic effects of gamma-radiation.

  3. DNA sequence analysis of spontaneous and gamma-radiation (anoxic)-induced lacId mutations in Escherichia coli umuC122::Tn5: differential requirement for umuC at G.C vs. A.T sites and for the production of transversions vs. transitions.

    PubMed

    Sargentini, N J; Smith, K C

    1994-12-01

    Escherichia coli umuC122::Tn5 cells were gamma-irradiated (137Cs, 750 Gy, under N2), and lac-constitutive mutants were produced at 36% of the wild-type level (the umuC strain was not deficient in spontaneous mutagenesis, and the mutational spectrum determined by sequencing 263 spontaneous lacId mutations was very similar to that for the wild-type strain). The specific nature of the umuC strain's partial radiation mutability was determined by sequencing 325 radiation-induced lacId mutations. The yields of radiation-induced mutation classes in the umuC strain (as a percentage of the wild-type yield) were: 80% for A.T-->G.C transitions, 70% for multi-base additions, 60% for single-base deletions, 53% for A.T-->C.G transversions, 36% for G.C-->A.T transitions, 25% for multi-base deletions, 21% for A.T-->T.A transversions, 11% for G.C-->C.G transversions, 9% for G.C-->T.A transversions, and 0% for multiple mutations. Based on these deficiencies and other factors, it is concluded that the umuC strain is near-normal for A.T-->G.C. transitions, single-base deletions and possibly A.T-->C.G transversions; is generally deficient for mutagenesis at G.C sites and for transversions, and is grossly deficient in multiple mutations. Damage at G.C sites seems more difficult for translesion DNA synthesis to bypass than damage at A.T sites, and especially when trying to produce a transversion. The yield of G.C-->A.T transitions in the umuC strain (36% of the wild-type level) argues that abasic sites are involved in no more than 64% of gamma-radiation-induced base substitutions in the wild-type strain. Altogether, these data suggest that the UmuC and UmuD' proteins facilitate, rather than being absolutely required for, translesion DNA synthesis; with the degree of facilitation being dependent both on the nature of the noncoding DNA damage, i.e., at G.C vs. A.T sites, and on the nature of the misincorporated base, i.e., whether it induces transversions or transitions.

  4. Genomic Instability Induced by Low Dose Irradiation

    SciTech Connect

    Evans, Helen H. Sedwick, David W. Veigl, Martina L.

    2006-07-15

    The goal of this project was to determine if genomic instability could be initiated by poorly repaired DNA damage induced by low doses of ionizing radiation leading to a mutator phenotype. Human cells were irradiated, then transfected with an unirradiated reporter gene at various times AFTER exposure. The vector carried an inactive GFP gene that fluoresced when the gene was activated by a delayed mutation. Fluorescent cells were measured in the interval of 50 hours to four days after transfection. The results showed that delayed mutations occurred in these cells after exposure to relatively low doses (0.3-1.0 Gy) of low or high ionizing radiation, as well as after treatment with hyrodgen peroxide (30-100 micromolar). The occurrence was both dose and time dependent, often decreasing at higher doses and later times. No marked difference was observed between the response of mis-match repair-proficient and -deficient cell lines. Although the results were quite reproducible within single experiments, difficulties were observed from experiment to experiment. Different reagents and assays were tested, but no improvement resulted. We concluded that this method is not sufficiently robust or consisent to be useful in the assay of the induction of genomic instability by low doses of radiation, at least in these cell lines under our conditions.

  5. External gamma radiation and mortality from cardiovascular diseases in the German WISMUT uranium miners cohort study, 1946-2008.

    PubMed

    Kreuzer, M; Dufey, F; Sogl, M; Schnelzer, M; Walsh, L

    2013-03-01

    It is currently unclear whether exposure of the heart and vascular system, at lifetime accumulated dose levels relevant to the general public (<500 mGy), is associated with an increased risk of cardiovascular disease. Therefore, data from the German WISMUT cohort of uranium miners were investigated for evidence of a relationship between external gamma radiation and death from cardiovascular diseases. The cohort comprises 58,982 former employees of the Wismut company. There were 9,039 recorded deaths from cardiovascular diseases during the follow-up period from 1946 to 2008. Exposures to external gamma radiation were estimated using a detailed job-exposure matrix. The exposures were based on expert ratings for the period 1946-1954 and measurements thereafter. The excess relative risk (ERR) per unit of cumulative gamma dose was obtained with internal Poisson regression using a linear ERR model with baseline stratification by age and calendar year. The mean cumulative gamma dose was 47 mSv for exposed miners (86 %), with a maximum of 909 mSv. No evidence for an increase in risk with increasing cumulative dose was found for mortality from all cardiovascular diseases (ERR/Sv = -0.13; 95 % confidence interval (CI): -0.38; 0.12) and ischemic heart diseases (n = 4,613; ERR/Sv = -0.03; 95 % CI: -0.38, 0.32). However, a statistically insignificant increase (n = 2,073; ERR/Sv = 0.44; 95 % CI: -0.16, 1.04) for mortality from cerebrovascular diseases was observed. Data on smoking, diabetes, and overweight are available for subgroups of the cohort, indicating no major correlation with cumulative gamma radiation. Confounding by these factors or other risk factors, however, cannot be excluded. In conclusion, the results provide weak evidence for an increased risk of death due to gamma radiation only for cerebrovascular diseases.

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

    PubMed

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

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  8. Neutron and gamma-radiation sensitivity of plasmid DNA of varying superhelical density

    SciTech Connect

    Swenberg, C.E.; Speicher, J.M.

    1995-12-01

    Several families of negatively supercoiled topoisomers of plasmid pIBI30 were prepared by a modification of the procedure of Singleton and Wells. The average superhelical density ({sigma}) was determined by two-dimensional agarose gel electrophoresis and varied from -0.010 to -0.067, corresponding to a change in the number of supercoils from 3 to 19 and an effective volume change from 1.6 x 10{sup 8} to 4 x 10{sup 8} {angstrom}{sup 3}. Samples were exposed to either fission-neutron or {sup 60}Co {gamma} radiation and assayed for single-strand breaks by agarose gel electrophoresis. Form I DNA for all topoisomers decreased exponentially with increasing dose. The D{sub 37} values for both neutron and {gamma} radiation increased monotonically with increasing {vert_bar}{sigma}{vert_bar}. Using a branched plectonemic (interwound) form for DNA over the range of {sigma} studied and standard (single-hit) target theory, a quantitative linear fit to (D{sub 37}{sup -1}) as a function of the effective DNA radius, S({angstrom}), was obtained. The model predicts that both the slope (a) and the intercept (b) of (D{sub 37}){sup -1} as a function of S({angstrom}) are directly proportional to the length of DNA and the radiation fluence. Furthermore, the ratio b/a (= r{sub o}) at {sigma} = 0 depends only on the ionic strength of the medium and is independent of the radiation source parameters. Our results support the model and we calculate r{sub o} = 13.4 {+-} 1.4 nm, a value consistent with other investigations. Our results are consistent with studies using {sup 137}Cs but disagree with data obtained for X rays. 31 refs., 6 figs., 1 tab.

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

    DOEpatents

    Hondorp, Hugh L.

    1984-01-01

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

  10. Effect and aftereffect of gamma radiation pretreatment on enzymatic hydrolysis of wheat straw.

    PubMed

    Yang, Chunping; Shen, Zhiqiang; Yu, Guoce; Wang, Jianlong

    2008-09-01

    Irradiation pretreatment of wheat straw was carried out at different doses by using Co-60 gamma radiation. The weight loss and fragility of wheat straw after irradiation, the combination effect of irradiation and mechanical crushing on enzymatic hydrolysis of wheat straw as well as the aftereffect of irradiation were examined. It is shown that irradiation can cause significant breakdown of the structure of wheat straw. The weight loss of wheat straw increased and the size distribution after crushing moved to fine particles at elevated irradiation doses. The glucose yield of enzymatic hydrolysis of wheat straw increased with increasing doses and achieved the maximum (13.40%) at 500 kGy. A synergistic effect between irradiation and crushing was observed, with a glucose yield of 10.24% at a dose of 500 kGy with powder of 140 mesh. The aftereffect of irradiation had important impact on enzymatic hydrolysis of wheat straw. The aftereffect (at 22nd day) of 400 kGy irradiation accounted for 20.0% of the initial effect for glucose production, and the aftereffects of 50, 100, 200 (at 9th day) and 300 kGy (at 20th day) accounted for 12.9%, 14.9%, 8.9% and 9.1%, respectively, for reducing sugar production.

  11. The effect of gamma radiation on the ultrastructure of sweet potatoes (Ipomoea batatas)

    SciTech Connect

    Brown, A.

    1986-12-01

    Radiation is being used to increase the storage life of fresh foods. Various doses of gamma radiation were administered to Jewel cultivar sweet potatoes and the effects were monitored by direct observation and by scanning and transmission electron microscopy. Potatoes were divided into two groups: those irradiated immediately after harvest (doses = 0 kGy - 0.4 KGy) and those irradiated one week after harvest (doses = 0 kGy - 0.4 kGy). Potatoes were examined and viewed each month for 7 months. Gross observations included weight, color and texture of the sweet potatoes. Those potatoes irradiated immediately after harvest spoiled faster than those irradiated one week after harvest. Scanning electron microscopy demonstrated several cellular modifications accompanying spoilage. Cell collapse was greatest at the higher radiation doses during the periods of 1 to 5 months post-irradiation. The shape and size of starch granules varied with storage time and radiation levels. The mitochondria, cell walls and plasma membranes appeared normal as seen by transmission electron microscopy until 6 months post-irradiation for potatoes irradiated both immediately after harvest and one week after harvest. Thereafter, degradative changes were observed.

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  13. Impact of gamma radiation on the eruption rate of rat incisors

    NASA Astrophysics Data System (ADS)

    El-Faramawy, Nabil; El-Haddad, Khaled; Ali, Mohamed; Talaat, Mona

    2015-09-01

    The present work aims to test the effect of gamma radiation on the rate of eruption of rat incisors. One hundred and five adult male albino rats were used and irradiated at different gamma doses. The effects of irradiation were investigated by numerical measurements of eruption rate, histological investigation using light microscope and spectral analysis using Fourier Transform Infra-Red (FTIR). No detectable changes were observed in the groups with smaller radiation doses. There was a significant decrease in the eruption rate starting from the 4 Gy radiation dose. The observation of histological sections revealed disturbance in cellular elements responsible for eruption as well as periodontal disturbance in the samples irradiated with 4 and 6 Gy. FTIR Spectroscopy of control group and the group irradiated by 0.5 Gy showed similar absorption bands with minor differences. However, samples irradiated by 1 Gy showed significant changes in both molecular structure and conformation related to carbonates and hydroxyl groups. From the previous results, it could be concluded that gamma irradiation negatively affects the eruption rate of the rat incisors especially with higher doses.

  14. Improvement of PVC floor tiles by gamma radiation

    NASA Astrophysics Data System (ADS)

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

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

  15. The origin of the diffuse background gamma-radiation

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  16. Gamma Radiation from PSR B1055-52

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  17. Gamma Radiation from PSR B1055-52

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  18. The origin of the diffuse background gamma radiation

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  19. Metformin and low dose radiation modulates cisplatin-induced oxidative injury in rat via PPAR-γ and MAPK pathways.

    PubMed

    Mansour, Heba H; El Kiki, Shereen M; Galal, Shereen M

    2017-02-15

    Cisplatin (CIS) is a chemotherapeutic agent used for therapy of many tumors and has been limited by its toxicity. The aim of this study was to investigate the role of Peroxisome proliferator-activated receptor-gamma (PPAR-γ), mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B(NFkB) in the pathogenesis of hepatic damage induced by CIS, and investigated the modulatory effect of metformin (MET) and/or low dose gamma radiation (LDR) on CIS-induced hepatotoxicity in rats. CIS(7.5 mg/kg, i.p.) hepatotoxicity was evidenced by alteration of serum hepatic indices (ALT and AST) accompanied with decreased hepatic PPAR-γ, superoxide dismutase (SOD) activities and reduced glutathione (GSH) content, whereas the levels of malondialdehyde (MDA), total nitrate/nitrite (NOx) and NFkB significantly increased as well as MAPK activity compared with the control, MET and LDR groups. Furthermore, CIS induces apoptosis as indicated by an elevation of hepatic caspase-3. Treatment with MET (150 mg/kg, orally for 14 days) and/or LDR (0.5 Gy), prior to CIS alleviates CIS-induced hepatic damage by mitigating oxidative/ nitrosative stress and PPAR-γ activity reduction, hepatic caspase-3 elevation, and inhibition of NFκB, and MAPK activity levels.

  20. Method for imaging quantum dots during exposure to gamma radiation

    NASA Astrophysics Data System (ADS)

    Immucci, Andrea N.; Chamson-Reig, Astrid; Yu, Kui; Wilkinson, Diana; Li, Chunsheng; Stodilka, Robert Z.; Carson, Jeffrey J. L.

    2011-03-01

    Quantum dots have been used in a wide variety of biomedical applications. A key advantage of these particles is that their optical properties depend predictably on size, which enables tuning of the emission wavelength. Recently, it was found that CdSe/ZnS quantum dots lose their ability to photoluminescence after exposure to gamma radiation (J. Phys. Chem. C., 113: 2580-2585 (2009). A method for readout of the loss of quantum dot photoluminescence during exposure to radiation could enable a multitude of real-time dosimetry applications. Here, we report on a method to image photoluminescence from quantum dots from a distance and under ambient lighting conditions. The approach was to construct and test a time-gated imaging system that incorporated pulsed illumination. The system was constructed from a pulsed green laser (Nd:YAG, 20 pulses/s, 5 ns pulse duration, ~5 mJ/pulse), a time-gated camera (LaVision Picostar, 2 ns gate width), and optical components to enable coaxial illumination and imaging. Using the system to image samples of equivalent concentration to the previous end-point work, quantum dot photoluminescence was measureable under ambient room lighting at a distance of 25 cm from the sample with a signal to background of 7.5:1. Continuous exposure of samples to pulsed laser produced no measureable loss of photoluminescence over a time period of one hour. With improvements to the light collection optics the range of the system is expected to increase to several metres, which will enable imaging of samples during exposure to a gamma radiation source.

  1. Gamma irradiation-induced oxidative stress and developmental impairment in the hermaphroditic fish, Kryptolebias marmoratus embryo.

    PubMed

    Rhee, Jae-Sung; Kim, Bo-Mi; Kang, Chang-Mo; Lee, Young-Mi; Lee, Jae-Seong

    2012-08-01

    This study investigated the effects of gamma radiation on the early developmental stages in hermaphroditic fish embryos of Kryptolebias marmoratus. The authors measured reactive oxygen species (ROS) level and antioxidant enzyme activities with the endpoint hatching rate after gamma irradiation of different embryonic stages. Then, the transcriptional changes of antioxidant enzyme-coding genes were evaluated by quantitative real-time reverse transcription polymerase chain reaction in response to gamma radiation on embryonic stages. Gamma radiation inhibited hatching rate and caused developmental impairment in a dose-dependent manner. Embryos showed tolerances in a developmental stage-dependent manner, indicating that early embryonic stages were more sensitive to the negative effects of gamma radiation than were later stages. After 5 Gy rate of radiation, the ROS level increased significantly at embryonic stages 2, 3, and 4 with a significant induction of all antioxidant enzyme activities. The expressions of glutathione S-transferase isoforms, catalase, superoxide dismutase (Mn-SOD, Cu/Zn-SOD), glutathione reductase, and glutathione peroxidase mRNA were upregulated in a dose-and-developmental stage-dependent manner. This finding indicates that gamma radiation can induce oxidative stress and subsequently modulates the expression of antioxidant enzyme-coding genes as one of the defense mechanisms. Interestingly, embryonic stage 1 exposed to gamma radiation showed a decreased expression in most antioxidant enzyme-coding genes, suggesting that this is also related to a lower hatching rate and developmental impairment. The results of this study provide a better understanding of the molecular mode of action of gamma radiation in aquatic organisms.

  2. Exploring the effects of low-level laser therapy on fibroblasts and tumor cells following gamma radiation exposure.

    PubMed

    Ramos Silva, Camila; Cabral, Fernanda Viana; de Camargo, Claudinei Francisco Morais; Núñez, Silvia Cristina; Mateus Yoshimura, Tania; de Lima Luna, Arthur Cássio; Maria, Durvanei Augusto; Ribeiro, Martha Simões

    2016-12-01

    Ionizing radiation (IR) induces DNA damage and low-level laser therapy (LLLT) has been investigated to prevent or repair detrimental outcomes resulting from IR exposure. Few in vitro studies, however, explore the biological mechanisms underlying those LLLT benefits. Thus, in this work, fibroblasts and tumor cells are submitted to IR with doses of 2.5 Gy and 10 Gy. After twenty-four-h, the cells are exposed to LLLT with fluences of 30 J cm(-2) , 90 J cm(-2) , and 150 J cm(-2) . Cellular viability, cell cycle phases, cell proliferation index and senescence are evaluated on days 1 and 4 after LLLT irradiation. For fibroblasts, LLLT promotes - in a fluence-dependent manner - increments in cell viability and proliferation, while a reduction in the senescence was observed. Regarding tumor cells, no influences of LLLT on cell viability are noticed. Whereas LLLT enhances cell populations in S and G2 /M cell cycle phases for both cellular lines, a decrease in proliferation and increase in senescence was verified only for tumor cells. Putting together, the results suggest that fibroblasts and tumor cells present different responses to LLLT following exposure to gamma-radiation, and these promising results should stimulate further investigations. Senescence of tumor cells and fibroblasts on the 4(th) day after ionizing radiation (IR) and low-level laser therapy (LLLT) exposures. The number of senescent cells increased significantly for tumor cells (a) while for fibroblasts no increment was observed (b). The blue collor indicates senescence activity.

  3. Field Deployable Gamma Radiation Detectors for DHS Use

    SciTech Connect

    Sanjoy Mukhopadhyay

    2007-08-01

    Recently, the Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial off-the-shelf and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable gamma radiation detectors that are attempting to meet the DNDO specifications. Commercially available, transportable, handheld radio isotope identification devices (RIID) are inadequate for DHS requirements in terms of sensitivity, resolution, response time, and reach-back capability. The leading commercial vendor manufacturing handheld gamma spectrometer in the United States is Thermo Electron Corporation. Thermo Electron's identiFINDER{trademark}, which primarily uses sodium iodide crystals (3.18 x 2.54cm cylinders) as gamma detectors, has a Full-Width-at-Half-Maximum energy resolution of 7 percent at 662 keV. Thermo Electron has just recently come up with a reach-back capability patented as RadReachBack{trademark} that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field. The current project has the goal to build a prototype handheld gamma spectrometer, equipped with a digital camera and an embedded cell phone to be used as an RIID with higher sensitivity, better resolution, and faster response time (able to detect the presence of gamma-emitting radio isotopes within 5 seconds of approach), which will make it useful as a field deployable tool. The handheld equipment continuously monitors the ambient gamma radiation, and, if it comes across any radiation anomalies with higher than normal gamma gross counts, it sets an alarm condition. When a substantial alarm level is reached, the system automatically triggers the saving of relevant

  4. Field Deployable Gamma Radiation Detectors for DHS Use

    SciTech Connect

    Sanjoy Mukhopadhyay

    2007-08-31

    Recently, the U.S. Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable gamma radiation detectors that are attempting to meet the DNDO specifications. Commercially available, transportable, handheld radio isotope identification devices (RIID) are inadequate for DHS’s requirements in terms of sensitivity, resolution, response time and reach back capability. The leading commercial vendor manufacturing handheld gamma spectrometer in the United States is Thermo Electron Corporation. Thermo Electron’s identiFINDER™, which primarily uses sodium iodide crystals (3.18-cm x 2.54-cm cylinders) as gamma detector, has a Full-Width-at-Half-Maximum energy resolution of 7 percent at 662 keV. Thermo Electron has just recently come up with a reach-back capability patented as RadReachBack™ that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field. The current project has the goal to build a prototype handheld gamma spectrometer, equipped with a digital camera and an embedded cell phone to be used as an RIID with higher sensitivity (comparable to that of a 7.62-cm x 7.62-cm sodium iodide crystal at low gamma energy ranging from 30 keV to 3,000 keV), better resolution (< 3.0 percent at 662 keV), faster response time (able to detect the presence of gamma-emitting radio isotopes within 5 seconds of approach), which will make it useful as a field deployable tool. The handheld equipment continuously monitors the ambient gamma radiation and, if it comes across any radiation anomalies with higher than normal gamma gross counts, it sets

  5. Field-deployable gamma-radiation detectors for DHS use

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy

    2007-09-01

    Recently, the Department of Homeland Security (DHS) has integrated all nuclear detection research, development, testing, evaluation, acquisition, and operational support into a single office: the Domestic Nuclear Detection Office (DNDO). The DNDO has specific requirements set for all commercial off-the-shelf and government off-the-shelf radiation detection equipment and data acquisition systems. This article would investigate several recent developments in field deployable gamma radiation detectors that are attempting to meet the DNDO specifications. Commercially available, transportable, handheld radio isotope identification devices (RIID) are inadequate for DHS' requirements in terms of sensitivity, resolution, response time, and reach-back capability. The leading commercial vendor manufacturing handheld gamma spectrometer in the United States is Thermo Electron Corporation. Thermo Electron's identiFINDER TM, which primarily uses sodium iodide crystals (3.18 x 2.54cm cylinders) as gamma detectors, has a Full-Width-at-Half-Maximum energy resolution of 7 percent at 662 keV. Thermo Electron has just recently come up with a reach-back capability patented as RadReachBack TM that enables emergency personnel to obtain real-time technical analysis of radiation samples they find in the field1. The current project has the goal to build a prototype handheld gamma spectrometer, equipped with a digital camera and an embedded cell phone to be used as an RIID with higher sensitivity, better resolution, and faster response time (able to detect the presence of gamma-emitting radio isotopes within 5 seconds of approach), which will make it useful as a field deployable tool. The handheld equipment continuously monitors the ambient gamma radiation, and, if it comes across any radiation anomalies with higher than normal gamma gross counts, it sets an alarm condition. When a substantial alarm level is reached, the system automatically triggers the saving of relevant spectral data and

  6. Effects of gamma radiation on development, sterility, fecundity, and sex ratio of Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae)

    SciTech Connect

    Entrekin, D.L.; Oliver, J.H. Jr.; Pound, J.M.

    1987-06-01

    Protonymphal Dermanyssus gallinae were irradiated with 0.50, 0.75, 1.0, 3.0, and 6.0 krad of gamma radiation and subsequently monitored regarding their developmental, feeding, and mating success. Also, sex ratios of adults treated as protonymphs were recorded as were sex ratios of embryos and F1 adults produced by these adults. Doses up to 1.0 krad did not prevent development of treated protonymphs to the adult stage or stop mating. Three krad reduced the number of treated protonymphs attaining adulthood and 6.0-krad treatment prevented all mites from developing to the adult stage. Egg (embryo) production was normal for mites treated with 0.50 krad, but significantly curtailed by doses of 0.75 krad and greater. Radiation doses used in this study did not appear to affect the normal variable sex ratios observed in untreated mites.

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

    SciTech Connect

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

    1988-10-01

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

  8. Gamma radiation synthesis of colloidal AgNPs for its potential application in antimicrobial fabrics

    NASA Astrophysics Data System (ADS)

    Bera, Anuradha; Garai, Purabi; Singh, Rita; Prakash Gupta, P.; Malav, Shatrughan; Singh, Durgeshwer; Kumar, Devendra; Tiwari, B. L.; Vaijapurkar, S. G.

    2015-10-01

    Highly stable colloidal solution of silver nanoparticles in a water-isopropanol-polyvinyl alcohol system was prepared through 60Co-gamma radiation at total dose of 35 kGy at dose rate of 5.67 kGy/h under nitrogen atmosphere. Ultraviolet-visible (UV-vis), X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) of the obtained colloidal solution indicated the formation of spherical shaped well mono dispersed silver nanoparticles with average diameter about 30 nm having very narrow size distribution. The radiolytically obtained nanosilver colloid was coated onto cotton fabrics by a simple industrial screen printing method and its adhesion with the fabric was found out by leaching studies using Atomic Absorption Spectrophotometry (AAS). Good adhesion was achieved by the adopted method wherein 89.5% of the coated nanosilver was retained in the fabric even after keeping the fabrics soaked in water for more than 60 h. Antimicrobial efficacy tests of the nanosilver coated cotton fabric showed that nanosilver coating is effective in killing both bacterial and fungal strains even at very low nanosilver loading (21.81 μgm/cm2). Nanosilver coating on the cotton fabric did not allow microbes (Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Candida albicans) to adhere and proliferate on fabric surface. Staphylococci (Staphylococcus aureus) and Yeast (Candida albicans) showed inhibition zones in presence of these nanosilver coated fabrics while no inhibition zone was observed with the uncoated control fabric.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

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

  11. Improved detector for the measurement of gamma radiation

    NASA Astrophysics Data System (ADS)

    Zelt, F. B.

    1985-07-01

    The present invention lies in the field of gamma ray spectrometry of geologic deposits and other materials, such as building materials (cement, asphalt, etc.) More specifically, the invention is an improved device for the gamma ray spetcrometery of gelogical deposits as a tool for petroleum exploration, geologic research and monitoring of radio-active materials such as in uranium mill tailings and the like. Improvement consists in enlarging the area of the receptor face and without any necessarily substantial increase in the volume of the receptor crystal over the current cylindrical shapes. The invention also provides, as a corollary of the increase in area receptor crystal face, a reduction in the weight of the amount of material necessary to provide effective shielding of the crystal from atmospheric radiation and radiation from deposits not under examination. The area of the receptor crystal face is increased by forming the crystal as a truncated cone with the shielding shaped as a hollow frustrum of a cone. A photomultiplier device is secured to the smaller face of the crystal. The improved detector shape can also be used in scintillometers which measure total gamma radiation.

  12. An experimental search for gamma radiation associated with thunderstorm activity

    SciTech Connect

    Fryberger, D.

    1992-11-01

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

  13. An experimental search for gamma radiation associated with thunderstorm activity

    SciTech Connect

    Fryberger, D.

    1992-11-01

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

  14. On the omnipresent background gamma radiation of the continuous spectrum

    NASA Astrophysics Data System (ADS)

    Banjanac, R.; Maletić, D.; Joković, D.; Veselinović, N.; Dragić, A.; Udovičić, V.; Aničin, I.

    2014-05-01

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

  15. Current Trends in Gamma Radiation Detection for Radiological Emergency Response

    SciTech Connect

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

    2011-09-01

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

  16. Current trends in gamma radiation detection for radiological emergency response

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Guss, Paul; Maurer, Richard

    2011-09-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

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

    DOEpatents

    Dioszegi, Istvan; Salwen, Cynthia; Vanier, Peter

    2014-12-30

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

  19. Up-regulation of 8-oxo-dGTPase activity of MTH1 protein in the brain, testes and kidneys of mice exposed to (137)Cs gamma radiation.

    PubMed

    Bialkowski, Karol; Szpila, Anna; Kasprzak, Kazimierz S

    2009-08-01

    Abstract Mammalian MTH1 protein is an antimutagenic (2'-deoxy)ribonucleoside 5'-triphosphate pyrophosphohydrolase that prevents the incorporation of oxidatively modified nucleotides into nucleic acids. It decomposes most specifically the miscoding products of oxidative damage to purine nucleic acid precursors (e.g. 8-oxo-dGTP, 2-oxo-dATP, 2-oxo-ATP, 8-oxo-GTP) that may cause point mutations or transcription errors when incorporated into DNA and RNA, respectively. The increased expression of MTH1 mRNA and MTH1 protein was previously proposed as a molecular marker of oxidative stress. Therefore, we hypothesized that increased 8-oxo-dGTPase activity of MTH1 protein in mouse organs could serve as a dose-dependent marker of exposure to ionizing radiation, which is known to induce oxidative stress. To test our hypothesis, we measured 8-oxo-dGTPase activity in six organs of male BL6 mice after exposure to 0, 10, 25 and 50 cGy and 1 Gy of (137)Cs gamma radiation given as a single whole-body dose (1 Gy/min). The mice were killed 4, 8 and 24 h after irradiation. A statistically significant induction of 8-oxo-dGTPase was found in brains, testes and kidneys but not in lungs, hearts or livers. Brains, which demonstrated the highest (4.3-fold) increase of 8-oxo-dGTPase activity, were shown to express approximately 50% higher levels of MTH1 protein. However, due to the lack of a simple positive correlation between the dose and the observed 8-oxo-dGTPase activity in brain, testes and kidneys, we conclude that measurements of 8-oxo-dGTPase activity in these organs may serve as a rough indicator rather than a quantifiable marker of radiation-induced oxidative stress.

  20. Influence of gamma radiation on microbiological parameters of the ethanolic fermentation of sugar-cane must

    NASA Astrophysics Data System (ADS)

    Alcarde, A. R.; Walder, J. M. M.; Horii, J.

    2003-04-01

    The influence of gamma radiation on reducing the population of some bacteria Bacillus and Lactobacillus that usually contaminate the sugar-cane must and its effects on acidity of the medium and viability of the yeast during fermentation were evaluated. The treatment with gamma radiation reduced the bacterial load of the sugar-cane must. Consequently, the volatile acidity produced during the fermentation of the must decreased and the viability of the yeast afterwards added increased.

  1. Cytogenetic comparison of the responses of mouse and human peripheral blood lymphocytes to /sup 60/Co gamma radiation

    SciTech Connect

    Kligerman, A.D.; Halperin, E.C.; Erexson, G.L.; Honore, G.; Westbrook-Collins, B.; Allen, J.W.

    1988-08-01

    Experiments were conducted to compare the chromosome damaging effects of /sup 60/Co gamma radiation on mouse and human peripheral blood lymphocytes (PBLs). Either whole blood or isolated and pelleted mononuclear leucocytes (MNLs) were irradiated with a /sup 60/Co unit to yield exposures of 1, 2, 3, or 4 Gy. In addition, mice were whole-body irradiated in vivo with the same doses so that an in vitro-in vivo comparison could be made. The results indicate that mouse PBLs irradiated in whole blood, whether in vivo or in vitro, respond similarly to /sup 60/Co gamma rays as measured by dicentric chromosome formation. In addition, mouse and human PBLs showed a similar radiosensitivity, but because the mouse PBL data were best fitted to an exponential function and the human PBL data to a quadratic function, direct comparisons were difficult to make. Pelleted MNLs from mice were much less sensitive to the clastogenic effects of gamma radiation than whole blood. This is believed to be due to hypoxic conditions that developed during irradiation and transport. Human PBLs did not show a marked difference whether irradiated in whole blood or as pelleted MNLs in tissue culture medium.

  2. Evidence for a Solar Influence on Gamma Radiation from Radon

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Steinitz, G.; Fischbach, E.; Javorsek, D.; Jenkins, J.

    2012-12-01

    We have analyzed 29,000 measurements of gamma radiation associated with the decay of radon confined to an airtight vessel at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between January 28 2007 and May 10 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis reveals a number of strong periodicities, including two at approximately 11.2 year-1 and 12.5 year-1. We consider it significant that these same oscillations have previously been detected in nuclear-decay data acquired at the Brookhaven National Laboratory and at the Physiklisch-Technische Bundesanstalt. We have suggested that these oscillations are due to some form of solar radiation (possibly neutrinos) that has its origin in the deep solar interior. A curious property of the GSI data is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. Time-frequency analysis also yields quite different results from daytime and nighttime data. These procedures have also been applied to data collected from subsurface geological sites in Israel, Tenerife, and Italy, which have a variety of geological and geophysical scenarios, different elevations, and depths below the surface ranging from several meters to 1000 meters. In view of these results, and in view of the fact that there is at present no clear understanding of the behavior of radon in its natural environment, there would appear to be a need for multi-disciplinary research. Investigations that clarify the nature and mechanisms of solar influences may help clarify the nature and mechanisms of geological influences.

  3. Networked gamma radiation detection system for tactical deployment

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald; Smith, Ethan; Guss, Paul; Mitchell, Stephen

    2015-08-01

    A networked gamma radiation detection system with directional sensitivity and energy spectral data acquisition capability is being developed by the National Security Technologies, LLC, Remote Sensing Laboratory to support the close and intense tactical engagement of law enforcement who carry out counterterrorism missions. In the proposed design, three clusters of 2″ × 4″ × 16″ sodium iodide crystals (4 each) with digiBASE-E (for list mode data collection) would be placed on the passenger side of a minivan. To enhance localization and facilitate rapid identification of isotopes, advanced smart real-time localization and radioisotope identification algorithms like WAVRAD (wavelet-assisted variance reduction for anomaly detection) and NSCRAD (nuisance-rejection spectral comparison ratio anomaly detection) will be incorporated. We will test a collection of algorithms and analysis that centers on the problem of radiation detection with a distributed sensor network. We will study the basic characteristics of a radiation sensor network and focus on the trade-offs between false positive alarm rates, true positive alarm rates, and time to detect multiple radiation sources in a large area. Empirical and simulation analyses of critical system parameters, such as number of sensors, sensor placement, and sensor response functions, will be examined. This networked system will provide an integrated radiation detection architecture and framework with (i) a large nationally recognized search database equivalent that would help generate a common operational picture in a major radiological crisis; (ii) a robust reach back connectivity for search data to be evaluated by home teams; and, finally, (iii) a possibility of integrating search data from multi-agency responders.

  4. Gamma radiation in the reduction of S almonella spp. inoculated on minimally processed watercress ( Nasturtium officinalis)

    NASA Astrophysics Data System (ADS)

    Martins, C. G.; Behrens, J. H.; Destro, M. T.; Franco, B. D. G. M.; Vizeu, D. M.; Hutzler, B.; Landgraf, M.

    2004-09-01

    Consumer attitudes towards foods have changed in the last two decades increasing requirements for freshlike products. Consequently, less extreme treatments or additives are being required. Minimally processed foods have freshlike characteristics and satisfy this new consumer demand. Besides freshness, the minimally processing also provide convenience required by the market. Salad vegetables can be source of pathogen such as Salmonella, Escherichia coli O157:H7, Shigella spp. The minimal processing does not reduce the levels of pathogenic microorganisms to safe levels. Therefore, this study was carried out in order to improve the microbiological safety and the shelf-life of minimally processed vegetables using gamma radiation. Minimally processed watercress inoculated with a cocktail of Salmonella spp was exposed to 0.0, 0.2, 0.5, 0.7, 1.0, 1.2 and 1.5 kGy. Irradiated samples were diluted 1:10 in saline peptone water and plated onto tryptic soy agar that were incubated at 37°C/24 h. D 10 values for Salmonella spp. inoculated in watercress varied from 0.29 to 0.43 kGy. Therefore, a dose of 1.7 kGy will reduce Salmonella population in watercress by 4 log 10. The shelf-life was increased by 1 {1}/{2} day when the product was exposed to 1 kGy.

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

    Brazil is a great producer of tropical fruits including mangoes. Among several purposes gamma radiation can be applied as phytosanitary treatment. This is well studied in scientific papers and more recently demonstrated through commercial advances like bilateral protocols established between India and USA. The whole experiment evolved two parts where each of them used fruits from different maturity stages (stages 2 and 3). This experiment was carried out with around 300 fruits in each part of the study. The main objective was to get the experience close to commercial conditions. The irradiation was realized in Multipurpose Cobalt-60 source belonging to IPEN-CNEN/SP (developed in house by own technology). The absorbed doses were 0.2, 0.5 and 0.75 kGy. After irradiation all fruits were kept at 12 °C in acclimatized chamber during 14 days. After this period the fruits were brought to environmental conditions (25 °C) for around 14 more days of duration. These conditions were established to simulate the exportation conditions from Brazil to distant countries. Physical-chemical analysis (pH, titrable acidity, total soluble solids (°Brix) and texture) as well as visual observation (mass loss, rotting, internal and skin color) were evaluated. The results from this experiment could demonstrate that the characteristics of the mangoes are more dependent on time and temperature storage rather than irradiation.

  6. Antibacterial properties of Au doped polycarbonate synthesized by gamma radiation assisted diffusion method

    NASA Astrophysics Data System (ADS)

    Hareesh, K.; Deore, Avinash V.; Dahiwale, S. S.; Sanjeev, Ganesh; Kanjilal, D.; Ojha, Sunil; Dhole, N. A.; Kodam, K. M.; Bhoraskar, V. N.; Dhole, S. D.

    2015-07-01

    Gold (Au)-Polycarbonate (PC) matrix was prepared by gamma radiation assisted diffusion of Au nanoparticles in PC matrix. UV-Visible spectroscopy showed the surface plasmon resonance around 550 nm which corresponds to Au and this peak shift towards lower wavelength i.e. blue shift indicating the decrease in particle size of Au. Rutherford Backscattering (RBS) experiment confirmed the diffusion of Au in PC and depth of diffusion is found to be around 0.85 μm. X-ray Diffractogram (XRD) results also revealed the diffusion of Au in PC where the peak observed at 2θ∼38.29° which correspond to the FCC structure. Scanning Electron Microscope (SEM) images showed the hexagonal shaped Au nanoparticles and average particle size is found to be around 110 nm. These samples also showed anti-bacterial properties with both gram positive and gram negative bacteria's and revealed the inhibition of the overall growth of the bacteria with gamma dose.

  7. Use of gamma radiation on control of Clostridium botulinum in mortadella formulated with different nitrite levels

    NASA Astrophysics Data System (ADS)

    Dutra, Monalisa Pereira; Aleixo, Glécia de Cássia; Ramos, Alcinéia de Lemos Souza; Silva, Maurício Henriques Louzada; Pereira, Marcio Tadeu; Piccoli, Roberta Hilsdorf; Ramos, Eduardo Mendes

    2016-02-01

    This study investigated the effects of applying different doses of gamma radiation (0, 10 and 20 kGy) on Clostridium botulinum spores (107 spores/g) inoculated into mortadellas with different nitrite contents (0, 150 and 300 ppm). We also evaluated the order of application of heat (cooking) and irradiation processing. The products were evaluated for survival of C. botulinum, pH, water activity (Aw), redox potential (Eh) and residual nitrite content. In the non-irradiated raw batters, almost all spores could be recovered when no nitrite was added and only half was recovered with the addition of 150 ppm of nitrite. The use of 150 ppm of nitrite was able to inhibit the germination or growth of C. botulinum in non-irradiated cooked mortadellas after 48 h of processing. However, after 30 days of chilling storage (4 °C), it was possible to recover 105 UFC/g of this microorganism. The gamma irradiation (>10 kGy) had a positive effect on the inactivation of C. botulinum in mortadellas, independent of the sodium nitrite level used and the cooking/irradiation processing order.

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

    PubMed Central

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

    2013-01-01

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

  9. Advances in commercial application of gamma radiation in tropical fruits at Brazil

    NASA Astrophysics Data System (ADS)

    Sabato, S. F.; Silva, J. M.; Cruz, J. N.; Broisler, P. O.; Rela, P. R.; Salmieri, S.; Lacroix, M.

    2009-07-01

    All regions of Brazil are potential areas for growing tropical fruits. As this country is already a great producer and exporter of tropical fruits, ionizing radiation has been the subject of studies in many commodities. An important project has been carried out to increase the commercial use of gamma radiation in our country. Instituto de Pesquisas Energeticas e Nucleares (IPEN)-CNEN/SP together with field producers in northeast region and partners like International Atomic Energy Agency (IAEA), CIC, Empresa Brasileira Pesquisa na Agricultura (EMBRAPA) joined to demonstrate this technology, its application and commercial feasibility. The objective of this study is to show advances in feasibility demonstrate the quality of the irradiated fruits in an international consignment from Brazil to Canada. In this work, Tommy Atkins mangoes harvested in northeast region of Brazil were sent to Canada. The fruits were treated in a gamma irradiation facility at doses 0.4 and 1.0 kGy. The control group was submitted to hydrothermal treatment (46 °C for 110 min). The fruits were stored at 11 °C for 10 days until the international transportation and kept at an environmental condition (22 °C) for 12 days, where their physical-chemical and sensorial properties were evaluated. The financial part of the feasibility study covers the scope of the investment, including the net working capital and production costs.

  10. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body.

    PubMed

    Pattison, John E

    2013-03-01

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant.

  11. Measurement of gamma radiation levels in soil samples from Thanjavur using γ-ray spectrometry and estimation of population exposure

    PubMed Central

    Senthilkumar, B.; Dhavamani, V.; Ramkumar, S.; Philominathan, P.

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using γ-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232Th, 238U and 40K is 42.9±9.4 Bq.kg−1, 14.7±1.7 Bq.kg−1 and 149.5±3.1 Bq.kg−1 respectively are derived from all the soil samples studied. The activity concentration of 232Th, 238U and 40K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h−1 and 59.1 nGy.h−1 with an arithmetic mean of 43.3 ±9 nGy.h−1. This value is lesser than the population weighted world-averaged of 60 nGy.h−1. Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 μSv.y−1 with an arithmetic mean of 53.1±11 μSv.y−1. The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels. PMID:20177570

  12. Measurement of gamma radiation levels in soil samples from Thanjavur using gamma-ray spectrometry and estimation of population exposure.

    PubMed

    Senthilkumar, B; Dhavamani, V; Ramkumar, S; Philominathan, P

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides (232)Th, (238)U and (40)K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using gamma-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of (232)Th, (238)U and (40)K is 42.9+/-9.4 Bq.kg(-1), 14.7+/-1.7 Bq.kg(-1) and 149.5+/-3.1 Bq.kg(-1) respectively are derived from all the soil samples studied. The activity concentration of (232)Th, (238)U and (40)K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h(-1) and 59.1 nGy.h(-1) with an arithmetic mean of 43.3 +/-9 nGy.h(-1). This value is lesser than the population weighted world-averaged of 60 nGy.h(-1). Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 muSv.y(-1) with an arithmetic mean of 53.1+/-11 muSv.y(-1). The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels.

  13. Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope - Part 1

    NASA Astrophysics Data System (ADS)

    El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; Maghraby, Ahmed; El-Zainy, Medhat

    2011-12-01

    In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope. For doses up to 0.5 Gy, there was no evidence of the existence of cracks on the enamel surface. With 1 Gy irradiation dose, cracks were clearly observed with localized erosive areas. At 2 Gy irradiation dose, the enamel showed morphological alterations as disturbed prismatic and interprismatic areas. An increase in dentinal tubules diameter and a contemporary inter-tubular dentine volume decrease were observed with higher irradiation dose. Concerning cementum, low doses,<0.5 Gy, showed surface irregularities and with increase in the irradiation dose to≥1 Gy, noticeable surface irregularities and erosive areas with decrease in Sharpey's fiber sites were observed. These observations could shed light on the hazardous effects of irradiation fields to the functioning of the human teeth.

  14. Variation in the radon concentrations and outdoor gamma radiation levels in relation to different geological formations in the thermal regions of Bursa, Turkey.

    PubMed

    Akkaya, Gizem; Kahraman, Ayşegül; Koray, Abdullah; Kaynak, Gökay

    2016-09-01

    Spring waters used as spas and their region may contain significant amounts of natural radionuclides. The main sources of exposure are the inhalation of radon and its decay products released from the water and soil and terrestrial gamma-radiation. In order to evaluate the potential risk of thermal regions in Bursa, located in the impact area of the NAF (North Anatolian Fault), radon and thoron concentrations in soil gas, radon concentrations in thermal waters and outdoor gamma radiation levels were measured in thermal regions that have different geological formations. The radon and thoron concentrations in soil-gas were found to vary from 2272  ±  121 to 245196  ±  3455 Bq m(-3) and from 999  ±  218 to 178 848  ±  17 742 Bq m(-3), respectively. The radon concentrations in thermal waters ranged from 0.99  ±  0.21 to 226.74  ±  2.51 Bq l(-1) in the rainy season and from 0.26  ±  0.10 to 178.03  ±  12.86 Bq l(-1) in the dry season. The measured outdoor gamma radiation levels varied from 38 to 180 nGy h(-1). The gamma dose rates were found to be strong positively correlating with the radon and thoron concentrations in soil-gas. The radon and outdoor gamma radiation levels were observed to be a function of the geological formations of the area.

  15. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay.

    PubMed

    Praveen Kumar, M K; Shyama, S K; Sonaye, B S; Naik, U Roshini; Kadam, S B; Bipin, P D; D'costa, A; Chaubey, R C

    2014-05-01

    Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of 'Comet assay' for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in both bivalve species. This showed a dose-dependent increase of genetic damage induced in bivalves by EMS as well as gamma radiation. Further, the highest DNA damage was observed at 24h. The damage gradually decreased with time, i.e. was smaller at 48 and 72 h than at 24h post irradiation in both species of bivalves. This may indicate repair of the damaged DNA and/or loss of heavily damaged cells as the post irradiation time advanced. The present study

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

    SciTech Connect

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

    2007-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    SciTech Connect

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

    2011-12-01

    Little is currently known about the effects of gamma-ray irradiation on oxide magnet materials. In particular, the effect of particle size on radiation susceptibility was investigated. Two commercial powders of BaFe{sub 12}O{sub 19} were thoroughly characterized, then exposed to 1 MGy of gamma radiation from a {sup 60}Co source. AC susceptibility and DC magnetometry and Moessbauer spectroscopy were performed after irradiation and compared to pre-irradiated measurements. DC magnetization and AC susceptibility decreased for both samples with the relative change of DC magnetization being larger for the micrometer-sized particles and the relative change of the AC susceptibility being larger for the nanometer-sized particles. Moessbauer spectroscopy indicated a decrease in both the hyperfine fields and in their distribution for each Fe site, particularly in the larger particle sample. Decreases in susceptibility are believed to be due to radiation-induced amorphization at the particle surfaces as well as amorphization and nucleation of new crystallites at internal crystallite boundaries, resulting in overall reduction in the particle magnetic moment. This radiation damage mechanism is different than that seen in previous studies of neutron and heavy ion irradiation of BaFe{sub 12}O{sub 19}.

  19. Neonatal low-dose gamma irradiation-induced impaired fertility in mature rats.

    PubMed

    Freud, A; Canfi, A; Sod-Moriah, U A; Chayoth, R

    1990-11-01

    The reproductive capacity of mature rats at the age of 8 days was studied following neonatal exposure to 0.06 Gy dose of gamma-radiation. Decreased litter size and reduced body weight of the pups on weaning day, but not at parturition, were observed in female rats. The reduced litter size was not associated with impaired ovulation, impaired uterine implantation or mortality in utero, but resulted from increased death rate or at near parturition. Of the neonatally irradiated males 29% were found to be sterile and had degenerated or necrotic testes. The testicular damage and the reduced growth rate of the offspring of the irradiated females demonstrate the extreme sensitivity of the immature reproductive system to ionizing radiation, even at very low doses.

  20. Influence of relaxation transitions on radiation-initiated cationic graft polymerization. [Gamma radiation

    SciTech Connect

    Kudryavtsev, V.N.; Kabanov, V.Ya.; Chalykh, A.E.; Spitsyn, V.I.

    1982-05-01

    Radiation grafting of vinyl n-butyl ether (VBE) to polyvinyl chloride (PVC) over a broad temperature range was investigated. The relaxation transitions in the PVC/VBE system were also determined. Grafting of vinyl alkyl ethers proceeds entirely by a cationic mechanism in a reaction medium that has been dried to a water concentration no greater than 0.1-1.0 ppm. In this connection, the diffusion properties of water in the temperature region were studied. Commercial films of unplasticized PVC (thickness 200 M); were subjected to swelling in two systems: in a 50% solution of VBE in benzene at 25/sup 0/C, and in the pure monomer at 40/sup 0/C. The reaction mixtures were first dried over metallic sodium in a deaerated atmosphere. The specimens were irradiated in a Co gamma-radiation unit to a dose of 10 kGy at a dose rate of 3 Gy/sec. The first reaction mixture was investigated over a range of temperatures from -60/sup 0/ to +70/sup 0/C, and the second from -15/sup 0/ to +50/sup 0/C. The degree of grafting was determined from the increase in weight of the original ungrafted film. The temperature was held to within +/-1/sup 0/C. The relaxation transitions in the swollen polymer systems were determined by two methods, thermostimulated current (TSC) and thermomechanics (TM). It was found that in the region of the glass transition of a swollen PVC-VBE system, radiation-initiated cationic graft polymerization proceeds at a maximal rate, and there are changes in state of the water molecules (the agents of breaking the ion reaction chain) and in their diffusion properties within the matrix.

  1. Accuracy of soil water content estimates from gamma radiation monitoring data

    NASA Astrophysics Data System (ADS)

    Mao, Jie; Huisman, Johan Alexander; Reemt Bogena, Heye; Vereecken, Harry

    2016-04-01

    Terrestrial gamma radiation is known to be sensitive to soil water content, and could be promising for soil water content determination because of the availability of continental-scale gamma radiation monitoring networks. However, the accuracy of soil water content estimates that can be obtained from this type of data is currently unknown. Therefore, the aim of this study is to assess the accuracy of soil water content estimates from measured time series of gamma radiation. For this, four gamma radiation monitoring stations were each equipped with four soil water content sensors at 5 and 15 cm depth to provide reference soil water content measurements. The contributions of terrestrial radiation and secondary cosmic radiation were separated from the total amount of measured gamma radiation by assuming that the long-term contribution of secondary cosmic radiation was constant, and that variations were related to changes in air pressure and incoming neutrons. In addition, precipitation effects related to atmospheric washout of radon progenies to the ground that cause an increase of gamma radiation were considered by excluding time periods with precipitation and time periods less than three hours after precipitation. The estimated terrestrial gamma radiation was related to soil water content using an exponential function with two fit parameters. For daily soil water content estimates, the goodness of fit ranged from R2= 0.21 to 0.48 and the RMSE ranged from 0.048 to 0.117 m3m-3. The accuracy of the soil water content estimates improved considerably when a weekly resolution was used (RMSE ranged from 0.029 to 0.084 m3m-3). Overall, these results indicate that gamma radiation monitoring data can be used to obtain useful soil water content information. The remaining differences between measured and estimated soil water content can at least partly be explained by the fact that the terrestrial gamma radiation is strongly determined by the upper few centimeters of the soil

  2. Sensory evaluation by gamma radiation effect on protein allergen of laying hen eggs

    NASA Astrophysics Data System (ADS)

    Harder, M. N. C.; Arthur, V.; Perina, V. C. S.; Silva, L. C. A. S.; Bortoleto, G. G.

    2012-08-01

    Although considered the most complete food and nutritionally shown to be part of a healthy diet, the egg is the source of many eating disorders, especially for infants. Irradiation has been used in studies not only as a means of microbiological control, but also on its structural action in the substances molecules and has been used to reduce the allergenic effects. The aim of this study was to evaluate the sensory effects of Co60 gamma radiation on proteins, enabling the acceptability of allergy food for genetically intolerant people. Eggs commercial fresh and freeze-dried and subjected to gamma irradiation by Co60 source at doses 0 (control), 10 kGy; 20 kGy and 30 kGy and rates of doses of 19.4 kGy/h and 31.8 kGy/h. Acceptability test was used by the hedonic scale, since it is necessary to know the "affective status" of consumers for the product, implying a preference, i.e. the most preferred samples are the most accepted and vice versa. The samples were presented as the habit of consumption (cooked) to a group of 41 adults panelists of both gender, aged from 21 to 40 years, and served under complete block design balanced with respect to the order of presentation. The evaluated attributes was flavor, appearance and overall acceptability. In general, for boiled eggs and freeze-dried, it was observed that the control sample was the most acceptable, followed by the sample irradiated with 10 kGy in both dose rates. In addition, panelists presented in testimony that they found interesting changes due to irradiation; also said they would not buy the product because of the marked change in appearance and smell, which at one point he ended up in disgust and detract from sales of the product, but they would buy irradiated with 10 kGy in both dose rate and dose of 20 kGy at a dose rate of 19.4 kGy/h.

  3. Study of a number of biochemical indices of the blood and tissue of dogs after prolonged gamma-radiation

    NASA Technical Reports Server (NTRS)

    Alers, I.; Alersova, E.; Praslichka, T.; Mishurova, E.; Sedlakova, A.; Malatova, Z.; Akhunov, A. A.; Markelov, B. A.

    1974-01-01

    The glucose content in blood and the lipid content in serum and tissues of dogs exposed to chronic radiation for 3 and 5 years were studied. In tissues of these animals, the concentration of soluble DNA and DNA contained in DNP was studied in the spleen, lymph node (deep cervical node) and bone marrow of thigh bones. Results indicate that chronic gamma irradiation significantly changes concentrations of glucose in the blood, and that of several lipids in serum and tissues. A reduction in the concentration of DNP in tested organs reflects changes in the relative number of cells with various nuclear cytoplasmic ratios; most pronounced changes in biochemical indices occur in dogs exposed to chronic gamma radiation in doses of 125 rad per year.

  4. Effect of gamma radiation on the expression of mRNA growth factors in glycerol cryopreserved human amniotic membrane.

    PubMed

    Yatim, Rusidah Mat; Kannan, Thirumulu Ponnuraj; Ab Hamid, Suzina Sheikh

    2016-12-01

    Human amniotic membrane (HAM) due to its high biocompatibility, low immunogenicity, anti-microbial, anti-viral properties as well as the presence of growth factors has been used in various clinical applications. The growth factors play an important role in wound healing. The current study aimed to explore the effect of 15 kGy gamma radiation dose on selected growth factors and receptors mRNA present in HAM. Eight growth factors, namely, EGF, HGF, KGF, TGF-α, TGF-β1, TGF-β2, TGF-β3 and bFGF and two growth factor receptors, HGFR and KGFR were evaluated in this study. The total RNA was extracted and converted to complimentary DNA using commercial kits. Subsequently, the mRNA expressions of these growth factors were evaluated using real-time PCR and the results were statistically analyzed using REST-MCS software. This study confirmed the presence of these mRNA growth factors and receptors in fresh, glycerol cryopreserved and irradiated glycerol cryopreserved HAM. In glycerol cryopreserved HAM, the results showed up-regulation of HGF and bFGF and down-regulation of EGF, HGFR, KGF, KGFR, TGF-α, TGF-β1, TGF-β2 and TGF-β3 relative to the fresh HAM which acted as the control, whereas in irradiated glycerol cryopreserved HAM, the results showed up-regulation of EGF, HGF, KGF, KGFR, TGF-β1, TGF-β2 and TGF-β3 and down-regulation of HGFR, TGF-α and bFGF relative to the glycerol cryopreserved HAM which acted as the control. However, these mRNA expressions did not show any statistical significant difference compared to the control groups. This study concluded that a dose of 15 kGy of gamma radiation did not affect the mRNA expression for the growth factors' and receptors' in the glycerol cryopreserved HAM.

  5. Ambient gamma radiation levels (indoor and outdoor) in the villages around Jaduguda (India) using card-based CaSO₄: Dy TL dosemeters.

    PubMed

    Maharana, Mandakini; Swarnkar, M; Chougaonkar, M P; Mayya, Y S; Sengupta, D

    2011-01-01

    A systematic study of the gamma radiation levels (indoor and outdoor) in the villages surrounding the uranium-enriched regions around Jaduguda, India has been undertaken by monitoring selected dwellings in six villages. Each dwelling unit was monitored for a total duration of 1 y. The gamma radiation measurements were carried out using card-based CaSO(4): Dy thermoluminescent dosemeters. The estimated average annual gamma dose values for indoor and outdoor were 980 and 924 (µGy y(-1)), respectively, for the entire region studied. The maximum indoor and outdoor gamma doses experienced in North Dungridih and South Dungridih villages were 1305 and 1223 (µGy y(-1)), respectively. The minimum indoor and outdoor gamma dose values observed in Chatikocha village were 624 and 696 (µGy y(-1)), respectively. Seasonal variation of the indoor gamma values was not observed during the year; however, a small variation was seen with the type of building materials used for construction purposes. A statistical analysis was attempted to characterise the distribution of terrestrial gamma radiation obtained in the study area. The average quarterly indoor gamma values for spring, summer, monsoon and winter seasons as prevalent in the regions were 267±71, 262±54, 213±91, 238±66 (µGy 90 d(-1)), respectively. The annual effective doses to the local population residing in the selected dwelling units were estimated to be 0.6 and 0.1 (mSv y(-1)) for indoor and outdoor, respectively, using an occupancy factor of 0.8 and 0.2.

  6. Ultra-low dose naltrexone enhances cannabinoid-induced antinociception.

    PubMed

    Paquette, Jay; Olmstead, Mary C; Olmstead, Mary

    2005-12-01

    Both opioids and cannabinoids have inhibitory effects at micromolar doses, which are mediated by activated receptors coupling to Gi/o-proteins. Surprisingly, the analgesic effects of opioids are enhanced by ultra-low doses (nanomolar to picomolar) of the opioid antagonist, naltrexone. As opioid and cannabinoid systems interact, this study investigated whether ultra-low dose naltrexone also influences cannabinoid-induced antinociception. Separate groups of Long-Evans rats were tested for antinociception following an injection of vehicle, a sub-maximal dose of the cannabinoid agonist WIN 55 212-2, naltrexone (an ultra-low or a high dose) or a combination of WIN 55 212-2 and naltrexone doses. Tail-flick latencies were recorded for 3 h, at 10-min intervals for the first hour, and at 15-min intervals thereafter. Ultra-low dose naltrexone elevated WIN 55 212-2-induced tail flick thresholds without extending its duration of action. This enhancement was replicated in animals receiving intraperitoneal or intravenous injections. A high dose of naltrexone had no effect on WIN 55 212-2-induced tail flick latencies, but a high dose of the cannabinoid 1 receptor antagonist SR 141716 blocked the elevated tail-flick thresholds produced by WIN 55 212-2+ultra-low dose naltrexone. These data suggest a mechanism of cannabinoid-opioid interaction whereby activated opioid receptors that couple to Gs-proteins may attenuate cannabinoid-induced antinociception and/or motor functioning.

  7. The biobehavioral and neuroimmune impact of low-dose ionizing radiation

    PubMed Central

    York, Jason M; Blevins, Neil A; Meling, Daryl D; Peterlin, Molly B; Gridley, Daila S; Cengel, Keith A; Freund, Gregory G

    2011-01-01

    In the clinical setting, repeated exposures (10–30) to low-doses of ionizing radiation (≤ 200 cGy), as seen in radiotherapy for cancer, causes fatigue. Almost nothing is known, however, about the fatigue inducing effects of a single exposure to environmental low-dose ionizing radiation that might occur during high-altitude commercial air flight, a nuclear reactor accident or a solar particle event (SPE). To investigate the short-term impact of low-dose ionizing radiation on mouse biobehaviors and neuroimmunity, male CD-1 mice were whole body irradiated with 50 cGy or 200 cGy of gamma or proton radiation. Gamma radiation was found to reduce spontaneous locomotor activity by 35% and 36%, respectively, 6 h post irradiation. In contrast, the motivated behavior of social exploration was un-impacted by gamma radiation. Examination of pro-inflammatory cytokine gene transcripts in the brain demonstrated that gamma radiation increased hippocampal TNF-α expression as early as 4 h post-irradiation. This was coupled to subsequent increases in IL-1RA (8 h and 12 h post irradiation) in the cortex and hippocampus and reductions in activity-regulated cytoskeleton-associated protein (Arc) (24 h post irradiation) in the cortex. Finally, restraint stress was a significant modulator of the neuroimmune response to radiation blocking the ability of 200 cGy gamma radiation from impairing locomotor activity and altering the brain-based inflammatory response to irradiation. Taken together, these findings indicate that low-dose ionizing radiation rapidly activates the neuroimmune system potentially causing early onset fatigue-like symptoms in mice. PMID:21958477

  8. Comparison of genotoxic potency of styrene 7,8-oxide with gamma radiation and human cancer risk estimation of styrene using the rad-equivalence approach.

    PubMed

    Godderis, Lode; Aka, P; Kirsch-Volders, M; Veulemans, H

    2007-05-01

    Styrene is suspected to cause lympho-hematopoietic malignancies through the formation of styrene 7,8-oxide. However, we are still unable to calculate the cancer risk for workers exposed to styrene using epidemiological data. The aims of this study were to determine the blood dose after styrene exposure and to compare the genotoxic potency of styrene 7,8-oxide and gamma radiation in order to calculate the cancer risk by means of the rad-equivalence approach. Leucocytes of 20 individuals were exposed to 0, 0.1, 0.2 or 0.3 mM styrene 7,8-oxide (1 h) or 1, 2 or 3 gray (=100, 200, 300 rad) gamma radiation. Genotoxicity was evaluated with the cytokinesis-block micronucleus assay. Comparison of the two slopes of the regression lines between micronuclei and dose revealed a genotoxic potency for styrene 7,8-oxide of 37 rad/mMh, corresponding with a median value derived from mutagenicity studies (1, 37, 208 rad/mMh). At exposure levels of 1 ppm styrene, a blood styrene 7,8-oxide concentration between 0.03 x 10(-)(6) and 0.42 x 10(-)(6) mM is to be expected using data of toxicokinetic models and human exposure studies. With the cancer risk per unit dose of gamma radiation as benchmark, we calculated a lifetime risk of acquiring a fatal lympho-hematopoietic cancer of 0.17 in 10(3) workers (between 0.037 x 10(-)(3) and 5.0 x 10(-)(3)) exposed to 20 ppm styrene during 40 years.

  9. Swelling and thermodynamic studies of temperature responsive 2-hydroxyethyl methacrylate/itaconic acid copolymeric hydrogels prepared via gamma radiation

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida L. J.; Mićić, Maja M.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2007-08-01

    The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 °C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 °C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 °C, in order to evaluate their potential for medical applications.

  10. On the mechanism of the interactions of neutrons and gamma radiation with nuclear graphite—Implications to HTGRs

    NASA Astrophysics Data System (ADS)

    Goodwin, C.; Barkatt, A.; Al-Sheikhly, M.

    2014-04-01

    Nuclear-grade varieties of graphite being considered for use in high-temperature gas reactors were exposed to gamma radiation (up to 87 MGy) and to fast neutrons (up to 5.4×1017 n/cm2 in air, 8.8×1011 n/cm2 in water-saturated helium). Results of XPS measurements indicated that gamma or mixed-field irradiation initially enhances the oxygen content in the surface region of the graphite, but this content decreases at higher doses, probably due to decomposition of surface CO complexes. Results of EPR measurements showed that gamma irradiation at low doses causes a decrease in the concentration of unpaired spins, but higher doses cause this concentration to rise. SQUID measurements of magnetic susceptibility support the EPR findings. At the dose range explored in this study, no structural changes were observed using XRD and Raman spectroscopy. In general, no significant differences were observed among the five varieties of graphite with respect to the effects of irradiation. Impurity analysis by means of GDMS and ICP-AES showed that impurity concentrations that concentrations of impurities, particularly those of neutron-absorbing impurities, were within the range specified for high-purity nuclear graphite. Activation relevant impurity concentrations, too, were very low.

  11. 77 FR 62267 - Proposed Extension of Existing Information Collection; Gamma Radiation Surveys

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-12

    ... be provided for all persons exposed to average gamma radiation measurements in excess of 2.0... to the person listed in the FOR FURTHER INFORMATION section of this notice. III. Current Actions The... as the total burden hours and burden costs supporting this information collection extension...

  12. Use of gamma radiation as a form of preservation of sweet potatoes. Quarterly progress report

    SciTech Connect

    Not Available

    1985-01-01

    This progress report covers: harvest and conditioning following harvest; effects of ..gamma.. radiation on the sweet potato weevil, organoleptic properties of sweet potatoes, protein content of same, and sweet potato quality (vitamins, color, texture, and carbohydrates). Evaluation of preliminary results indicate that changes should be made in irradiation procedures/conditions and analyses. (DLC)

  13. Use of gamma radiation as a form of preservation of sweet potatoes

    NASA Astrophysics Data System (ADS)

    The effects of (GAMMA) radiation on the sweet potato weevil, organoleptic properties of sweet potatoes, protein content of same, and sweet potato quality (vitamins, color, texture, and carbohydrates) are discussed. Evaluation of preliminary results indicate that changes should be made in irradiation procedures/conditions and analyses.

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  15. Comparison of antibodies raised against heat-and gamma radiation-killed bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For antibody generation, pathogenic bacteria are often heat-treated prior to inoculation into host animals in order to prevent infection and subsequently, premature death of the host. Inoculation of host rabbits with gamma radiation-killed pathogenic bacteria was employed with the hopes of generati...

  16. Measuring the activity of a 51Cr neutrino source based on the gamma-radiation spectrum

    NASA Astrophysics Data System (ADS)

    Gorbachev, V. V.; Gavrin, V. N.; Ibragimova, T. V.; Kalikhov, A. V.; Malyshkin, Yu. M.; Shikhin, A. A.

    2015-12-01

    A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of 51Cr is presented.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. [Gamma-radiation action on cells of algae Euglena gracilis].

    PubMed

    Glinkova, E; Zhuchkina, N I; Koltovoĭ, N A; Koltovaia, N A

    2012-01-01

    Considering the potentials of algae Euglena to constitute a part of biological systems of human life support, effects of low radiation doses on algal cells and radiosensitivity dependence on their genotype were studied. In experiments with gamma-irradiation (60Co) of Euglena gracilis, the highest radioresistance was demonstrated by strain Z. OFL; the chloroplasts lacking Z-derived strain showed hypersensitivity to radiation. E. bacillaris and derived chlorophyll-lacking strains W3 and W10 had intermediate radiosensitivity. Irradiation with the doses of up to 10 Gy produced a hormetic effect in the stock strains. Cells death was observed only after irradiation by doses above 100 Gy. The stimulating effect was exerted both on radioresistance and growth rate. Dyes made possible rapid evaluation of the proportion of living and dead cells. Comparison of two survival tests showed that the classic medium inoculation overestimates cell deaths as it disregards the living non-proliferating cells.

  19. Gamma radiation effects on some properties of YBCO

    NASA Astrophysics Data System (ADS)

    Luo, L.; Zhang, Y. H.; Hu, S. H.; Liu, W. H.; Zhang, G. L.; Hu, W. X.

    1991-07-01

    Radiation effects of polycrystalline YBCO bulk sample irradiated by 60Co γ-rays, dose of 1×10 6 up to 7.5×10 8 rad, at room temperature on critical temperature and critical current were investigated. IR spectrum was also used to study the mechanism of the irradiation. A considerably strong dependence of these parameters upon the irradiation dose was observed. No significant effects on the critical temperature were found, but the critical current in zero magnetic field changed greatly. It shows a tendency to decrease with the increase of the irradiation dose except for a slight increase with the dose less than about 2×10 7 rad and no simple relations between critical currents and irradiation doses was found. A typical case is that the critical current is reduced to about 60% when the dose reaches 5×10 9 rad, but the dependence of critical currents on the magnetic field shows that the critical currents are higher than those of the unirradiated one in the range of magnetic field higher than 100 G and decrease more slowly in a magnetic field compared with the unirradiated one. The results indicate that the defects produced by γ-ray irradiation are beneficial to flux pinning in higher fields. IR spectra analysis reveals that the intensity of the peak responsible for the Cu(1)- O(1) chain vibration is decreased, indicating that the bond of the Cu(1)-O(1) may be partly broken through collision process of the Compton electron produced by the γ-ray. This effect probably gives rise to a decrease of the critical currents.

  20. Environmental gamma radiation measurement in district Swat, Pakistan.

    PubMed

    Jabbar, T; Khan, K; Subhani, M S; Akhter, P; Jabbar, A

    2008-01-01

    External exposure to environmental gamma ray sources is an important component of exposure to the public. A survey was carried out to determine activity concentration levels and associated doses from (226)Ra, (232)Th, (40)K and (137)Cs by means of high-resolution gamma ray spectrometry in the Swat district, famous for tourism. The mean concentrations for (226)Ra, (232)Th and (40)K were found to be 50.4 +/- 0.7, 34.8 +/- 0.7 and 434.5 +/- 7.4 Bq kg(-1), respectively, in soil samples, which are slightly more than the world average values. However, (137)Cs was only found in the soil sample of Barikot with an activity concentration of 34 +/- 1.2 Bq kg(-1). Only (40)K was determined in vegetation samples with an average activity of 172.2 +/- 1.7 Bq kg(-1), whereas in water samples, all radionuclides were found below lower limits of detection. The radium equivalent activity in all soil samples is lower than the limit set in the Organisation for Economic Cooperation and Development report (370 Bq kg(-1)). The value of the external exposure dose has been determined from the content of these radionuclides in soil. The average terrestrial gamma air absorbed dose rate was observed to be 62.4 nGy h(-1), which yields an annual effective dose of 0.08 mSv. The average value of the annual effective dose lies close to the global range of outdoor radiation exposure given in United Nations Scientific Committee on the Effects of Atomic Radiation. However, the main component of the radiation dose to the population residing in the study area arises from cosmic ray due to high altitude.

  1. Is Gamma Radiation Suitable to Preserve Phenolic Compounds and to Decontaminate Mycotoxins in Aromatic Plants? A Case-Study with Aloysia citrodora Paláu.

    PubMed

    Pereira, Eliana; Barros, Lillian; Antonio, Amilcar L; Cabo Verde, Sandra; Santos-Buelga, Celestino; Ferreira, Isabel C F R; Rodrigues, Paula

    2017-02-23

    This study aimed to determine the effect of gamma radiation on the preservation of phenolic compounds and on decontamination of dry herbs in terms of ochratoxin A (OTA) and aflatoxin B1 (AFB1), using Aloysia citrodora Paláu as a case study. For this purpose, artificially contaminated dry leaves were submitted to gamma radiation at different doses (1, 5, and 10 kGy; at dose rate of 1.7 kGy/h). Phenolic compounds were analysed by HPLC-DAD-ESI/MS and mycotoxin levels were determined by HPLC-fluorescence. Eleven phenolic compounds were identified in the samples and despite the apparent degradation of some compounds (namely verbasoside), 1 and 10 kGy doses point to a preservation of the majority of the compounds. The mean mycotoxin reduction varied between 5.3% and 9.6% for OTA and from 4.9% to 5.2% for AFB1. It was not observed a significant effect of the irradiation treatments on mycotoxin levels, and a slight degradation of the phenolic compounds in the irradiated samples was observed.

  2. Mediate gamma radiation effects on some packaged food items

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

  3. Effects of gamma radiation on fetal development in mice

    PubMed Central

    Dehghan, Tahere; Mozdarani, Hossein; Khoradmehr, Arezoo; Kalantar, Seyed Mehdi

    2016-01-01

    Background: Many cancer patients receive radiotherapy which may lead to serious damages to the ovary storage and the matrix muscle state. Some of these patients may admit to infertility clinics for having pregnancy and on the other hand hormonal administration for superovulation induction is a routine procedure in assisted reproduction technology (ART) clinics. Objective: This study aimed to investigate fertility and fetuses of hormone treated super ovulated female mice who had received whole-body gamma irradiation before mating. Materials and Methods: Female mice were randomly categorized into a control group and 3 experimental groups including: Group I (Irradiation), Group II (Superovulation), and Group III (Superovulation and Irradiation). In hormone treated groups, mice were injected with different doses of pregnant mare's serum gonadotropin (PMSG) followed with human chorionic gonadotropin (HCG). Irradiation was done using a Co-60 gamma ray generator with doses of 2 and 4 Gy. Number of fetuses counted and the fetus’s weight, head circumference, birth height, the number of live healthy fetuses, the number of fetuses with detected anomalies in the body, the sum of resorption and arrested fetuses were all recorded as outcome of treatments. Results: In the group I and group II, increased radiation and hormone dose led to a decrease in the number of survived fetuses (45 in 2 Gy vs. 29 in 4 Gy for irradiated group) as well as from 76 in 10 units into 48 in 15 units. In the group III, a higher dose of hormone in the presence of a 2 Gy irradiation boosted the slink rate; i.e. the number of aborted fetuses reached 21 cases while applying the dose of 15 Iu, whereas 6 cases of abortion were reported applying the hormone with a lower dose. Among different parameters studied, there was a significant difference in parameters of weight and height in the mouse fetuses (p=0.01). Conclusion: The data indicated that use of ovarian stimulating hormones in mice that received pre

  4. Enhancement of the grafting performance and of the water absorption of cassava starch graft copolymer by gamma radiation

    NASA Astrophysics Data System (ADS)

    Kiatkamjornwong, Suda; Meechai, Nispa

    1997-06-01

    Enhancement of the gamma radiation grafting of acrylonitrile onto gelatinized cassava starch was investigated. Infrared spectrometry was used to follow the chemical changes in the grafting reaction and from saponification. The saponified starch- g-PAN (HSPAN) was then characterized in terms of grafting parameters to provide a guide for the optimum total dose (kGy) and the appropriate ratio of starch/acrylonitrile for a fixed dose rate of 2.5 × 10 -1 kGy/min. Other dose rates were also carried out to obtain the appropriate result of grafting copolymerization and of water absorption. A thin aluminium foil, covering the inner wall of the reaction vessel, was found to be far more effective than any other metal films in the enhancement of the grafting reaction and the water absorption as well. Nitric acid in the medium increases the grafting yield and the water absorption. Methyl ether hydroquinone inhibitor was evaluated for its ability to increase homopolymerization and decrease graft reaction. When styrene was used as a comonomer, it hampered the grafting of acrylonitrile onto starch backbone. The water absorption capacity was improved by freeze-drying the HSPAN. The treatment of the HSPAN with aluminium trichloride hexahydrate was found to enhance the degree of wicking, but to decrease the water absorbency.

  5. Effect of Gamma Irradiation on Cement Composites Observed with XRD and SEM Methods in the Range of Radiation Dose 0-1409 MGy

    NASA Astrophysics Data System (ADS)

    Łowińska-Kluge, A.; Piszora, P.

    2008-08-01

    The effect of gamma radiation in the range of 0-1409 MGy on the structure of a new mineral additive to cement based composites was investigated in the perspective of employing them as radioactive waste protection material. According to the authors knowledge, it is the first paper dealing with observations of the cement matrix, both pure and modified, treated with so giant radiation dose. The absorption of gamma radiation modifies the morphology of the additive grains, causes decomposition of cement hydrates and clinker relicts in cement paste containing the additive at twice higher radiation dose than that inducing the decomposition of the reference pure cement paste and the cement paste containing pozzolane additives.

  6. Natural gamma-radiation in the Aeolian volcanic arc.

    PubMed

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

    2001-11-01

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

  7. Low-dose cyclophosphamide-induced acute hepatotoxicity

    PubMed Central

    Subramaniam, S. Ravih; Cader, Rizna Abdul; Mohd, Rozita; Yen, Kong Wei; Ghafor, Halim Abdul

    2013-01-01

    Patient: Male, 48 Final Diagnosis: Low dose cyclophosphamide-induced acute hepatotoxicity Symptoms: Epigastric pain Medication: Withdrawal of cyclophosphamide Clinical Procedure: — Specialty: Nephrology • Hepatology • Gastroenterology • Toxicology Objective: Unexpected drug reaction Background: Cyclophosphamide is commonly used to treat cancers, systemic vasculitides, and kidney diseases (e.g., lupus nephritis and focal segmental glomerulosclerosis). Acute adverse effects include bone marrow suppression, hemorrhagic cystitis, nausea, vomiting, and hair loss. Hepatotoxicity with high dose cyclophosphamide is well recognized but hepatitis due to low dose cyclophosphamide has rarely been described. Case Report: We report the case of a 48-year-old Chinese man with a rapidly progressive glomerulonephritis secondary to granulomatosis with polyangiitis who developed severe acute hepatic failure within 24 hours of receiving low-dose intravenous cyclophosphamide. The diagnosis of granulomatosis with polyangiitis was supported with a positive c-ANCA serology. The patient was treated with high dose methylprednisolone, plasmapheresis, intermittent hemodialysis, and low-dose intravenous cyclophosphamide. Conclusions: Hepatotoxicity may occur even after low-dose intravenous cyclophosphamide treatment. To the best of our knowledge, this is the first report of severe, non-viral, liver inflammation developing within 24 hours of administration of low-dose intravenous cyclophosphamide (200 mg). Physicians should be aware of this serious adverse reaction and should not repeat the cyclophosphamide dose when there is hepatotoxicity caused by the first dose. Initial and follow-up liver function tests should be monitored in all patients receiving cyclophosphamide treatment. PMID:24023976

  8. Radiation-induced changes in the cuticular hydrocarbons of the granary weevil and their relationship to desiccation and adult mortality

    SciTech Connect

    Sriharan, S. . Div. of Natural and Applied Sciences)

    1989-07-01

    Radiation from the nuclear waste products, such as Cesium-137, offers a scope and could be used for large scale disinfestation of grain. It is known that 0.15 to 0.20 kGy dose of gamma radiation is sufficient to kill insects in grain and grain products. However, the mode of action (in terms of lethal effects) is not understood. The purpose of this project, therefore, is to study the ways in which gamma radiation causes death in the granary weevil. Sitophilus granarius (L.) is a major and cosmopolitan pest of stored grain all over the world. Radiation damage, in particular the specific effects on the physiology of the insects exposed to radiation has been elucidated. In stored grain insects, conservation of water is a critical factor for their survival. Epicuticular hydrocarbons play an important role in water proofing. The laboratory rearing of the granary weevil was standardized so that large numbers of weevils of known ages could be produced for experimentation. Stock cultures were maintained at 27 {plus minus} 2{degree}C and 65 {plus minus} 5% R.H. Tests with various age groups (adults) and different doses of gamma radiation indicate that lethal effects are both age and dose related. Younger weevils, in general, survive for a longer period after irradiation compared to older weevils. Complete mortality results within about two weeks after exposure to gamma radiation at dose of 0.15 kGy or above. Data on wet and dry weights of the weevils kept at different (low, medium and higher) levels of humidity after irradiation indicate that gamma radiation induces greater water loss leading to desiccation and early death. Low humidity environment (17% R.H.) greatly accelerates lethal effects.

  9. Protective Effects of Hydrogen against Low-Dose Long-Term Radiation-Induced Damage to the Behavioral Performances, Hematopoietic System, Genital System, and Splenic Lymphocytes in Mice

    PubMed Central

    Lei, Xiao; Zhao, Hainan; Liu, Pengfei; Xu, Yang; Chen, Yuanyuan; Chuai, Yunhai

    2016-01-01

    Molecular hydrogen (H2) has been previously reported playing an important role in ameliorating damage caused by acute radiation. In this study, we investigated the effects of H2 on the alterations induced by low-dose long-term radiation (LDLTR). All the mice in hydrogen-treated or radiation-only groups received 0.1 Gy, 0.5 Gy, 1.0 Gy, and 2.0 Gy whole-body gamma radiation, respectively. After the last time of radiation exposure, all the mice were employed for the determination of the body mass (BM) observation, forced swim test (FST), the open field test (OFT), the chromosome aberration (CA), the peripheral blood cells parameters analysis, the sperm abnormality (SA), the lymphocyte transformation test (LTT), and the histopathological studies. And significant differences between the treatment group and the radiation-only groups were observed, showing that H2 could diminish the detriment induced by LDLTR and suggesting the protective efficacy of H2 in multiple systems in mice against LDLTR. PMID:27774116

  10. Low doses of neutrons induce changes in gene expression

    SciTech Connect

    Woloschak, G.E.; Chang-Liu, C.M. ); Panozzo, J.; Libertin, C.R. )

    1993-01-01

    Studies were designed to identify genes induced following low-dose neutron but not following [gamma]-ray exposure in fibroblasts. Our past work had shown differences in the expression of [beta]-protein kinase C and c-fos genes, both being induced following [gamma]-ray but not neutron exposure. We have identified two genes that are induced following neutron, but not [gamma]-ray, exposure: Rp-8 (a gene induced by apoptosis) and the long terminal repeat (LTR) of the human immunodeficiency (HIV). Rp-8 mRNA induction was demonstrated in Syrian hamster embryo fibroblasts and was found to be induced in cells exposed to neutrons administered at low (0.5 cGy/min) and at high dose rate (12 cGy/min). The induction of transcription from the LTR of HIV was demonstrated in HeLa cells bearing a transfected construct of the chloramphenicol acetyl transferase (CAT) gene driven by the HIV-LTR promoter. Measures of CAT activity and CAT transcripts following irradiation demonstrated an unresponsiveness to [gamma] rays over a broad range of doses. Twofold induction of the HIV-LTR was detected following neutron exposure (48 cGy) administered at low (0.5 cGy/min) but not high (12 cGy/min) dose rates. Ultraviolet-mediated HIV-LTR induction was inhibited by low-dose-rate neutron exposure.

  11. Low doses of neutrons induce changes in gene expression

    SciTech Connect

    Woloschak, G.E.; Chang-Liu, C.M.; Panozzo, J.; Libertin, C.R.

    1993-06-01

    Studies were designed to identify genes induced following low-dose neutron but not following {gamma}-ray exposure in fibroblasts. Our past work had shown differences in the expression of {beta}-protein kinase C and c-fos genes, both being induced following {gamma}-ray but not neutron exposure. We have identified two genes that are induced following neutron, but not {gamma}-ray, exposure: Rp-8 (a gene induced by apoptosis) and the long terminal repeat (LTR) of the human immunodeficiency (HIV). Rp-8 mRNA induction was demonstrated in Syrian hamster embryo fibroblasts and was found to be induced in cells exposed to neutrons administered at low (0.5 cGy/min) and at high dose rate (12 cGy/min). The induction of transcription from the LTR of HIV was demonstrated in HeLa cells bearing a transfected construct of the chloramphenicol acetyl transferase (CAT) gene driven by the HIV-LTR promoter. Measures of CAT activity and CAT transcripts following irradiation demonstrated an unresponsiveness to {gamma} rays over a broad range of doses. Twofold induction of the HIV-LTR was detected following neutron exposure (48 cGy) administered at low (0.5 cGy/min) but not high (12 cGy/min) dose rates. Ultraviolet-mediated HIV-LTR induction was inhibited by low-dose-rate neutron exposure.

  12. Gamma radiation monitoring at the Eastern North Atlantic (ENA), Graciosa Island ARM facility

    NASA Astrophysics Data System (ADS)

    Barbosa, Susana; Miranda, Pedro; Azevedo, Eduardo B.; Nitschke, Kim

    2016-04-01

    Continuous monitoring of gamma radiation is often performed in nuclear facilities and industrial environments as a way to control the ambient radioactivity and give warning of potential accidents. However, gamma radiation is also ubiquitous in the natural environment. The main sources are i) cosmic radiation from space, including secondary radiation from the interaction with atoms in the atmosphere, ii) terrestrial sources from mineral grains in soils and rocks, particularly Potassium (K-40), Uranium (U-238) and Thorium (Th-232) and their decay products (e.g. Radium, Ra-226) , and iii) airborne Radon gas (Rn-222), which is the dominant source of natural environmental radioactivity. The temporal variability of this natural radiation background needs to be well understood and quantified in order to discriminate non-natural sources of radiation in the environment and artificial radionuclides contamination. To this end, continuous gamma radiation monitoring is being performed at the Eastern North Atlantic (ENA) facility located in the Graciosa island (Azores, 39N; 28W), a fixed site of the Atmospheric Radiation Measurement programme (ARM), established and supported by the Department of Energy (DOE) of the United States of America with the collaboration of the local government and University of the Azores. The site is unique for the study of the natural radioactivity background on one hand due to the remote oceanic geographical location, in the middle of the North Atlantic Ocean and clear of direct continental influence, and on the other hand because of the comprehensive dataset of atmospheric parameters that is available for enhancing the interpretation of the radiation measurements, as a result of the vast array of very detailed and high-quality atmospheric measurements performed at the ARM-ENA facility. Gamma radiation in the range 475 KeV to 3000 KeV is measured continuously with a 3" x 3" NaI(Tl) scintillator. The campaign started started in May 2015, with gamma

  13. A FTIR/chemometrics approach to characterize the gamma radiation effects on iodine/epoxy-paint interactions in Nuclear Power Plants.

    PubMed

    Colombani, Juliette; Chauvet, Elodie; Amat, Sandrine; Dupuy, Nathalie; Gigmes, Didier

    2017-04-01

    The effects of radiation on polymeric materials are a topic of concern in a wide range of industries including the sterilization, and the nuclear power industry. While much work has concentrated on systems like polyolefins that are radiation sterilized, some work has been done on epoxy systems. The epoxy system studied is an epoxy/amine paint which is representative of the paint that covers the inner surfaces of the French nuclear reactor containment buildings. In case of a severe accident on a Nuclear Power Plant, fission products can be released from the nuclear fuel to the reactor containment building. Among them, volatile iodine (I2) can be produced and can interact with the epoxy-paint. This paint is also subjected to gamma radiation damages (due to the high dose in the containment coming from radionuclides released from the fuel). So the epoxy-paint studied was exposed to gamma radiation under air atmosphere after being loaded with I2 or not. The aim of this study is to characterize by FTIR spectroscopy the iodine-paint interactions, then to identify the radiation damages on the epoxy-paint, and to check their effects on these iodine-paint interactions. This work shows the potential of multi-block analysis method (ANOVA-PCA and COMDIM = AComDim) for such a study as it allows to identify the nature of iodine/epoxy-paint interactions and to characterize the gamma radiation damages on the epoxy-paint. AComDim method conduces to the extraction of Common Components to different tables and highlights factors of influence and their interactions.

  14. The Dose Window for Radiation-Induced Protective Adaptive Responses

    PubMed Central

    Mitchel, Ronald E. J.

    2009-01-01

    Adaptive responses to low doses of low LET radiation occur in all organisms thus far examined, from single cell lower eukaryotes to mammals. These responses reduce the deleterious consequences of DNA damaging events, including radiation-induced or spontaneous cancer and non-cancer diseases in mice. The adaptive response in mammalian cells and mammals operates within a certain window that can be defined by upper and lower dose thresholds, typically between about 1 and 100 mGy for a single low dose rate exposure. However, these thresholds for protection are not a fixed function of total dose, but also vary with dose rate, additional radiation or non-radiation stressors, tissue type and p53 functional status. Exposures above the upper threshold are generally detrimental, while exposures below the lower threshold may or may not increase either cancer or non-cancer disease risk. PMID:20585438

  15. [Mechanism of cytogenetic adaptive response induced by low dose radiation].

    PubMed

    Cai, L; Liu, S

    1990-11-01

    Cytogenetic observation on human lymphocytes indicated that pre-exposure of 10, 50 and 75 mGy X-rays could induced the adaptive response. Experimental results with different temperature treatment showed that the adaptive response induced by low dose radiation could be enhanced by 41 degrees C and 43 degrees C, but inhibited by 4 degrees C in addition the treatment by 41 degrees C for one hour could also cause the adaptive response as did low dose radiation. Results showed that adaptive response induced by low dose radiation (10 or 50 mGy X-rays) could be eliminated by the protein synthesis inhibitor, implying that the adaptive response is related with the metabolism of cells, especially with the production of certain protective proteins.

  16. HMSPP nanocomposite and Brazilian bentonite properties after gamma radiation exposure

    NASA Astrophysics Data System (ADS)

    Fermino, D. M.; Parra, D. F.; Oliani, W. L.; Lugao, A. B.; Díaz, F. R. V.

    2013-03-01

    This work concerns the study of the mechanical and thermal behavior of the nanocomposite high melt strength polypropylene (HMSPP) (obtained at a dose of 12.5 kGy) and a bentonite clay Brazilian Paraiba (PB), which is known as "chocolate" and is used in concentrations of 5% and 10% by weight, in comparison to the American Cloisite 20A clay nanocomposites. An agent compatibilizer polypropylene-graft (PP-g-AM) was added at a 3% concentration, and the clay was dispersed using the melt intercalation technique using a twin-screw extruder. The specimens were prepared by the injection process. The mechanical behavior was evaluated by strength, flexural strength and impact tests. The thermal behavior was evaluated by the techniques of differential scanning calorimetry (DSC) and thermogravimetry (TGA). The morphology of the nanocomposites was studied with scanning electron microscopy (SEM), while the organophilic bentonite and nanocomposites were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR).

  17. Petroleum and diesel sulfur degradation under gamma radiation

    NASA Astrophysics Data System (ADS)

    Andrade, Luana dos Santos; Calvo, Wilson Aparecido Parejo; Sato, Ivone Mulako; Duarte, Celina Lopes

    2015-10-01

    Hydrodesulfurization (HDS) is currently the most common method used by refineries to remove sulfur compounds from petroleum fractions. However, it is not highly effective for removing thiophene compounds such as benzothiophene. Additionally, this process generates high costs for the oil industry. In the present work, ionizing radiation was used in order to study the effect on the degradation of petroleum and diesel sulfur compounds. Crude oil and diesel fuel samples were studied, without any pretreatment, and irradiated using a cobalt-60 gamma cell in a batch system at absorbed doses of 30 kGy and 50 kGy. The sulfur compounds were extracted and then analyzed by gas chromatography associated with mass spectrometry (GCMS). A high efficiency of ionizing radiation was observed regarding the degradation of sulfur compounds such as benzothiophene and benzenethiol and the formation of fragments, for example 1.2-dimethylbenzene and toluene.

  18. EPR dosimetry in a mixed neutron and gamma radiation field.

    PubMed

    Trompier, F; Fattibene, P; Tikunov, D; Bartolotta, A; Carosi, A; Doca, M C

    2004-01-01

    Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident absorbed dose, analyzed results show the EPR potentiality and complementarity with regular criticality techniques.

  19. Gamma radiation resistant Fabry-Perot fiber optic sensors

    NASA Astrophysics Data System (ADS)

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

    2002-08-01

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

  20. Evaluation of gamma radiation levels for reducing pathogenic bacteria and fungi in animal sewage and laboratory effluents.

    PubMed Central

    Garcia, M M; Brooks, B W; Stewart, R B; Dion, W; Trudel, J R; Ouwerkerk, T

    1987-01-01

    Sewage samples collected from animal wastes and from effluents at an animal disease laboratory were inoculated with known numbers of pathogenic organisms and subjected to various doses of gamma radiation from a 60Co source. Surviving test organisms were quantitatively determined by selective and enrichment techniques. The experiment was modeled as a quantal assay in which probit analysis was applied to obtain D10 values. The D10 value represents the irradiating dose required to reduce the population by 90%. The D10 value ranged from 13.4 krad for Campylobacter fetus to 156.6 krad for Streptococcus faecalis in animal sewage. However, the D10 value for the laboratory effluent was generally lower. Based on the estimated D10 values, the rating of the test organisms in decreasing order of radiosensitivity appeared as follows: Brucella abortus, Campylobacter fetus subsp. fetus, Campylobacter jejuni, Campylobacter coli, Campylobacter laridis, Mycobacterium fortuitum, Aspergillus fumigatus, Salmonella muenster, Candida albicans, Clostridium difficile and Streptococcus faecalis. If the D5 and D1 values were utilized, this listing would be only slightly altered. PMID:3651881

  1. Assessment effect of gamma radiation on the flight ability of the peach fruit fly, Bactrocera zonata (Saunders).

    PubMed

    El-Gendy, Ismail Ragab; El-Aw, M A M; Hashem, A G; Draz, K A

    2013-12-01

    The sterile insect technique is one of the most methods of fruit flies control. Flight ability of the Peach Fruit Fly (PFF), Bactrocera zonata was conducted under laboratory conditions to evaluate the effect of gamma radiation on flight ability of PFF, B. zonata. Pupae of PFF, B. zonata, were irradiated in an air atmosphere at 24, 48 and 72 h before adult emergence with three doses of Cobalt 60 (10, 30 and 50 Gray) and tested against 6, 12 and 20 cm tube heights. Flight Ability Percentage (FAP) of PFF was carried out for newly emerged flies and six-days-old of adult flies. FAP of newly emerged-and six- days-old of adult flies was inversely proportional to the tube heights, doses of gamma rays and with progress the age of flies. The FAP value was significantly higher at 6 cm tube height, followed by 12 cm then 20 cm tube heights for all tested levels of gamma rays, respectively.

  2. Foxp3(+)-Treg cells enhanced by repeated low-dose gamma-irradiation attenuate ovalbumin-induced allergic asthma in mice.

    PubMed

    Park, Bum Soo; Hong, Gwan Ui; Ro, Jai Youl

    2013-05-01

    Gamma radiation is used for several therapeutic indications such as cancers and autoimmune diseases. Low-dose whole-body γ irradiation has been shown to activate immune responses in several ways, however, the effect and mechanism of irradiation on allergic asthma remains poorly understood. This study investigated whether or not irradiation exacerbates allergic asthma responses and its potential mechanism. C57BL/6 mice were sensitized and challenged with ovalbumin (OVA) to induce asthma. The mice received whole-body irradiation once daily for 3 consecutive days with a dose of 0.667 Gy using (137)Cs γ rays 24 h before every OVA challenge. Repeated low-dose irradiation reduced OVA-specific IgE levels, the number of inflammatory cells including mast cells, goblet cell hyperplasia, collagen deposition, airway hyperresponsiveness, expression of inflammatory cytokines, CCL2/CCR2, as well as nuclear factor kappa B (NF-κB) and activator protein-1 activities. All of these factors were increased in BAL cells and lung tissue of OVA-challenged mice. Irradiation increased the number of Treg cells, expression of interleukin (IL)-10, IL-2 and IL-35 in BAL cells and lung tissue. Irradiation also increased Treg cell-expressed Foxp3 and IL-10 by NF-κB and RUNX1 in OVA-challenged mice. Furthermore, while Treg cell-expressing OX40 and IL-10 were enhanced in lung tissue or act-bone marrow-derived mast cells (BMMCs) with Treg cells, but BMMCs-expressing OX40L and TGF-β were decreased. The data suggest that irradiation enhances Foxp3(+)- and IL-10-producing Treg cells, which reduce OVA-induced allergic airway inflammation and tissue remodeling through the down-regulation of migration by the CCL2/CCR2 axis and activation of mast cells via OX40/OX40L in lung tissue of OVA-challenged mice.

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

    PubMed Central

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  5. Radiation-induced genomic instability: radiation quality and dose response

    NASA Technical Reports Server (NTRS)

    Smith, Leslie E.; Nagar, Shruti; Kim, Grace J.; Morgan, William F.

    2003-01-01

    Genomic instability is a term used to describe a phenomenon that results in the accumulation of multiple changes required to convert a stable genome of a normal cell to an unstable genome characteristic of a tumor. There has been considerable recent debate concerning the importance of genomic instability in human cancer and its temporal occurrence in the carcinogenic process. Radiation is capable of inducing genomic instability in mammalian cells and instability is thought to be the driving force responsible for radiation carcinogenesis. Genomic instability is characterized by a large collection of diverse endpoints that include large-scale chromosomal rearrangements and aberrations, amplification of genetic material, aneuploidy, micronucleus formation, microsatellite instability, and gene mutation. The capacity of radiation to induce genomic instability depends to a large extent on radiation quality or linear energy transfer (LET) and dose. There appears to be a low dose threshold effect with low LET, beyond which no additional genomic instability is induced. Low doses of both high and low LET radiation are capable of inducing this phenomenon. This report reviews data concerning dose rate effects of high and low LET radiation and their capacity to induce genomic instability assayed by chromosomal aberrations, delayed lethal mutations, micronuclei and apoptosis.

  6. A comparison of 4 MeV Proton and Co-60 gamma irradiation induced degradation in the electrical characteristics of N-channel MOSFETs

    NASA Astrophysics Data System (ADS)

    Anjum, Arshiya; Vinayakprasanna, N. H.; Pradeep, T. M.; Pushpa, N.; Krishna, J. B. M.; Gnana Prakash, A. P.

    2016-07-01

    N-channel depletion MOSFETs were irradiated with 4 MeV Proton and Co-60 gamma radiation in the dose range of 100 krad(Si) to 100 Mrad(Si). The electrical characteristics of MOSFET such as threshold voltage (Vth), density of interface trapped charges (ΔNit), density of oxide trapped charges (ΔNot), transconductance (gm), mobility (μ), leakage current (IL) and drain saturation current (ID Sat) were studied as a function of dose. A considerable increase in ΔNit and ΔNot and decrease in Vth,gm, μ, and ID Sat was observed after irradiation. The results of 4 MeV Proton irradiation were compared with that of Co-60 gamma radiation and it is found that the degradation is more for the devices irradiated with 4 MeV Protons when compared with the Co-60 gamma radiation. This indicates that Protons induce more trapped charges in the field oxide region when compared to the gamma radiation.

  7. Sewage sludge pasteurization by gamma radiation: A Canadian demonstration project — 1988-91

    NASA Astrophysics Data System (ADS)

    Swinwood, Jean F.; Wilson, Bruce K.

    Nordion International Inc. and a Canadian city, in cooperation with the Federal & Provincial Ministries of the Environment, began a project in 1988 to construct and operate a commercial-scale sewage sludge pasteurization facility using gamma radiation technology. The facility is scheduled to begin operations in 1991. This paper discusses the objectives and scope of the project, the design of the irradiation system, and the plans to market the pasteurized sludge as a high-value, organic soil conditioner and fertilizer.

  8. Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

    NASA Astrophysics Data System (ADS)

    Singh, Durgeshwer; Singh, Rita

    2012-11-01

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

  9. Characterization of muon and gamma radiations at the PTOLEMY site

    NASA Astrophysics Data System (ADS)

    Betts, Susannah; Gentile, Charles; Tully, Chris; Zapata, Sandra; Chris Tully Collaboration

    2013-10-01

    PTOLEMY is an experimental project at Princeton Plasma Physics Laboratory designed to determine the present day number density of relic neutrinos through measurement of electrons produced from neutrino capture on tritium. The weak interaction cross section for relic neutrino interactions necessitates high sensitivity measurements that could be influenced by high energy particles, like muons and gamma ray photons, which induce nuclear transitions and secondary electrons. Muons produced from the collision of cosmic rays with atmospheric nuclei are a significant source of background radiation at and below Earth's surface. The muon flux is measured by the coincidence of minimum ionization radiation loss in two plastic scintillator paddles. The spectrum of gamma ray photons is measured using sodium iodide based scintillators. These measurements will provide a characterization of the background and rates at the PTOLEMY site.

  10. Dose and volume impact on radiation-induced xerostomia.

    PubMed

    Marmiroli, Luca; Salvi, Giovanna; Caiazza, Adolfo; Di Rienzo, Luigi; Massaccesi, Mariangela; Murino, Paola; Macchia, Gabriella

    2005-01-01

    Radiation-induced xerostomia consists in the chronic dryness of the mouth caused by parotid gland irradiation. Parotid glands produce approximately 60% of saliva while the rest is secreted by submandibular and accessory salivary glands. Methods of measuring the salivary output are essentially represented by 99mTc-pertechnate scintigraphy or simpler albeit less accurate methods in stimulated or unstimulated saliva. There are subjective and objective criteria of classification and grading of the secretion of saliva. Radiation-induced xerostomia, namely the residual salivary gland function is evidently associated with the mean dose absorbed. The salivary output tends to decrease after the end of radiotherapy. The partial dose-volume is substantially correlated with the mean dose to the whole gland. As for ipsilateral irradiation for head and neck cancer, conformal RT or IMRT allow to spare the contralateral parotid gland without increasing the risk of contralateral nodal recurrences. The monitoring system of late toxicity used by the authors is presented.

  11. Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPARγ-Independent Up-Regulation of Reactive Oxygen Species-Induced Deoxyribonucleic Acid Damage Signals in Non-Small Cell Lung Cancer Cells

    SciTech Connect

    Han, Eun Jong; Im, Chang-Nim; Park, Seon Hwa; Moon, Eun-Yi; Hong, Sung Hee

    2013-04-01

    Purpose: To investigate possible radiosensitizing activities of the well-known peroxisome proliferator-activated receptor (PPAR)γ ligand ciglitazone and novel PPARγ ligands CAY10415 and CAY10506 in non-small cell lung cancer (NSCLC) cells. Methods and Materials: Radiosensitivity was assessed using a clonogenic cell survival assay. To investigate the mechanism underlying PPARγ ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPARγ ligands and γ-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPARγ ligands induced cell death and ROS generation in a PPARγ-independent manner, enhanced γ-radiation–induced apoptosis and caspase-3–mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPARγ ligand/γ-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-γ ligands may enhance the γ-radiation-induced DNA damage response, possibly by increasing γ-H2AX expression. Moreover, the combination treatment significantly increased ROS generation, and the ROS scavenger N-acetylcysteine inhibited the combined treatment-induced ROS generation and apoptotic cell death. Conclusions: Taken together, these results indicated that the combined treatment of PPARγ ligands and γ-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.

  12. Synthesis of polytetrafluoroethylene based olefinic copolymer by gamma radiation grafting

    NASA Astrophysics Data System (ADS)

    Ferreto, H. F. R.; Lima, L. F. C. P.; Parra, D. F.; Zaia, V.; Lugão, A. B.

    2007-12-01

    High speed extrusion of linear low density polyethylene (LLDPE) is limited by processes shortcoming known as 'melt fracture' and 'sharkskin', which are surface defect of the extruded polymer. This defect results in a product with a rough surface that lacks luster and with poor surface properties. The fluoropolymer processing additives are used to eliminate the surface defect by coating the die wall and inducing slip at the coated fluoropolymer surface/LLDPE interface. The aim of this study was to obtain a recycled polytetrafluoroethylene polymer grafted with an olefin that could improve the extrudability of the LLDPE. The copolymer was obtained by irradiating recycled PTFE in an inert atmosphere followed by grafting an olefinic monomer the polymeric matrix (PTFE). After a certain time of contact, the copolymer was heat treated to allow recombination and elimination of the radicals, both in a reactive and/or inert atmosphere. The olefinic monomer used was 1,3-butadiene. The 1,3-butadiene monomer was found to be more effective with respect to grafting. The specimens were studied using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). The obtained copolymer (0.2-2.0 wt%) was mixed with LLDPE. The rheological properties of the mixture were determined with a torque rheometer. The results indicated that the developed process rendered a copolymer which when added to LLDPE, improved the extrusion process and eliminated the defect 'melt fracture'.

  13. Dose-dependent changes in the locomotor responses to methamphetamine in BALB/c mice: low doses induce hypolocomotion.

    PubMed

    Singh, Rana A K; Kosten, Therese A; Kinsey, Berma M; Shen, Xiaoyun; Lopez, Angel Y; Kosten, Thomas R; Orson, Frank M

    2012-12-01

    The overall goal of the present study was to determine the effects of different doses of (+)-methamphetamine (meth) on locomotor activity of Balb/C mice. Four experiments were designed to test a wide range of meth doses in BALB/c female mice. In Experiment 1, we examined locomotor activity induced by an acute administration of low doses of meth (0.01 and 0.03mg/kg) in a 90-min session. Experiment 2 was conducted to test higher meth doses (0.3-10mg/kg). In Experiment 3, separate sets of mice were pre-treated with various meth doses once or twice (one injection/week) prior to a locomotor challenge with a low meth dose. Finally, in Experiment 4, we tested whether locomotor activation would be affected by pretreatment with a low or moderate dose of meth one month prior to the low meth dose challenge. Results show that low doses of meth induce hypolocomotion whereas moderate to high doses induce hyperlocomotion. Prior exposure to either one moderate or high dose of meth or to two, low doses of meth attenuated the hypolocomotor effect of a low meth dose one week later. This effect was also attenuated in mice tested one month after administration of a moderate meth dose. These results show that low and high doses of meth can have opposing effects on locomotor activity. Further, prior exposure to the drug leads to tolerance, rather than sensitization, of the hypolocomotor response to low meth doses.

  14. Tolerance to Gamma Radiation in the Tardigrade Hypsibius dujardini from Embryo to Adult Correlate Inversely with Cellular Proliferation

    PubMed Central

    Beltrán-Pardo, Eliana; Jönsson, K. Ingemar; Harms-Ringdahl, Mats; Haghdoost, Siamak; Wojcik, Andrzej

    2015-01-01

    Tardigrades are highly tolerant to desiccation and ionizing radiation but the mechanisms of this tolerance are not well understood. In this paper, we report studies on dose responses of adults and eggs of the tardigrade Hypsibius dujardini exposed to gamma radiation. In adults the LD50/48h for survival was estimated at ~ 4200 Gy, and doses higher than 100 Gy reduced both fertility and hatchability of laid eggs drastically. We also evaluated the effect of radiation (doses 50 Gy, 200 Gy, 500 Gy) on eggs in the early and late embryonic stage of development, and observed a reduced hatchability in the early stage, while no effect was found in the late stage of development. Survival of juveniles from irradiated eggs was highly affected by a 500 Gy dose, both in the early and the late stage. Juveniles hatched from eggs irradiated at 50 Gy and 200 Gy developed into adults and produced offspring, but their fertility was reduced compared to the controls. Finally we measured the effect of low temperature during irradiation at 4000 Gy and 4500 Gy on survival in adult tardigrades, and observed a slight delay in the expressed mortality when tardigrades were irradiated on ice. Since H. dujardini is a freshwater tardigrade with lower tolerance to desiccation compared to limno-terrestrial tardigrades, the high radiation tolerance in adults, similar to limno-terrestrial tardigrades, is unexpected and seems to challenge the idea that desiccation and radiation tolerance rely on the same molecular mechanisms. We suggest that the higher radiation tolerance in adults and late stage embryos of H. dujardini (and in other studied tardigrades) compared to early stage embryos may partly be due to limited mitotic activity, since tardigrades have a low degree of somatic cell division (eutely), and dividing cells are known to be more sensitive to radiation. PMID:26208275

  15. Tolerance to Gamma Radiation in the Tardigrade Hypsibius dujardini from Embryo to Adult Correlate Inversely with Cellular Proliferation.

    PubMed

    Beltrán-Pardo, Eliana; Jönsson, K Ingemar; Harms-Ringdahl, Mats; Haghdoost, Siamak; Wojcik, Andrzej

    2015-01-01

    Tardigrades are highly tolerant to desiccation and ionizing radiation but the mechanisms of this tolerance are not well understood. In this paper, we report studies on dose responses of adults and eggs of the tardigrade Hypsibius dujardini exposed to gamma radiation. In adults the LD50/48h for survival was estimated at ~ 4200 Gy, and doses higher than 100 Gy reduced both fertility and hatchability of laid eggs drastically. We also evaluated the effect of radiation (doses 50 Gy, 200 Gy, 500 Gy) on eggs in the early and late embryonic stage of development, and observed a reduced hatchability in the early stage, while no effect was found in the late stage of development. Survival of juveniles from irradiated eggs was highly affected by a 500 Gy dose, both in the early and the late stage. Juveniles hatched from eggs irradiated at 50 Gy and 200 Gy developed into adults and produced offspring, but their fertility was reduced compared to the controls. Finally we measured the effect of low temperature during irradiation at 4000 Gy and 4500 Gy on survival in adult tardigrades, and observed a slight delay in the expressed mortality when tardigrades were irradiated on ice. Since H. dujardini is a freshwater tardigrade with lower tolerance to desiccation compared to limno-terrestrial tardigrades, the high radiation tolerance in adults, similar to limno-terrestrial tardigrades, is unexpected and seems to challenge the idea that desiccation and radiation tolerance rely on the same molecular mechanisms. We suggest that the higher radiation tolerance in adults and late stage embryos of H. dujardini (and in other studied tardigrades) compared to early stage embryos may partly be due to limited mitotic activity, since tardigrades have a low degree of somatic cell division (eutely), and dividing cells are known to be more sensitive to radiation.

  16. Modification of fecundity and fertility during oogenesis by. gamma. radiation and/or ozone with a cytological analysis in the ectoparasitic wasp, Habrobracon juglandis (Ashmead)

    SciTech Connect

    Ofuoku, E.E.

    1984-01-01

    In Experiment I, adult female wasps were exposed to ozone for 0, 2, 4, 6, 8, 10, 12, 16, 24, and 27 h. The results indicated that the 27 h of ozone exposure produced 100% lethality on the first day. Exposures below 27 h progressively decreased life span with increasing length of exposure. In Experiment II A, adult virgin Habrobracon females were exposed to ozone for 0, 2, 4, 6, 8, 10, 12, 16, and 24 h to determine the effects of ozone on fecundity (egg laying ability) and fertility (egg hatching ability). The results showed that ozone significantly decreased fecundity and fertility in all meiotic stages except metaphase I. In Experiment II B, adult virgin Habrobracon females were exposed to Co-60 ..gamma.. radiation. All treated wasps showed significant progressive decreases in fecundity and fertility with increases in radiation dose. In Experiment II C, adult virgin Habrobracon females were exposed to Co-60 ..gamma.. radiation, to ozone, or to combinations thereof to determine the effects of these insults on fecundity and fertility. Together or singly ozone and radiation reduced fecundity and fertility. In Experiment III, adult virgin Habrobracon females were exposed to the conditions of Experiment II C to correlate by cytological examination of the ovarioles the effects of ionizing radiation and/or ozone on the germ cells at specific meiotic stages. Results obtained from the cytological study explain the fecundity and fertility observations.

  17. AP-PCR assay of DNA alterations in the progeny of male mice exposed to low-level gamma-radiation.

    PubMed

    Vasil'eva, G V; Bezlepkin, V G; Lomaeva, M G; Sirota, N P; Gaziev, A I

    2001-03-07

    By comparative analysis of fingerprints of arbitrarily primed polymerase chain reaction (AP-PCR) products, DNA alterations in somatic cells of the progeny (F1 generation) of male mice chronically exposed to low-doses of gamma-radiation was investigated. Male BALB/c mice exposed to 10-50 cGy were mated with unirradiated females 15 days after irradiation. DNA was isolated from biopsies taken from tail tips of 2-month-old progeny. Preliminary AP-PCRs were carried out with 17 primers representing core sequences of micro- and/or minisatellites or their flanking oligonucleotides. Best quantitatively reproduced AP-PCR fingerprints of genomic DNA were obtained with one of these primers, a 20-mer oligonucleotide flanking the micro-satellite locus Atplb2 on mouse chromosome 11. Comparative analysis of individual fingerprints of AP-PCR products obtained on DNA templates from the progeny of irradiated and intact males revealed an increased variability of micro-satellite-associated sequences and an increased frequency of "non-parental bands" in DNA-fingerprints from the progeny of males chronically exposed to gamma-radiation 15 days before mating (at the postmeiotic stage of spermatogenesis). The results show that increased micro-satellite instability can be initiated by irradiation of the male parent to subsequently arise or be transmitted to the soma of the F1 generations.

  18. Physical changes associated with gamma doses on Wood/ Polypropylene Composites

    NASA Astrophysics Data System (ADS)

    Ndiaye, Diène; Tidjani, Adams

    2014-08-01

    The effect of gamma- radiation on the morphology, thermal behavior and mechanical properties of wood polypropylene composites has been investigated. Simultaneous thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been performed on WPC samples of (9.5 ± 0.1) mg. These samples were exposed to different gamma-dose in the range 10 to 100kGy. The results indicated that gamma radiation improves the mechanical properties while the thermal stability is decreased. With gamma radiation, the scanning electron microscopy (SEM) of the micrographs became smoother and we can notice an improvement of interaction between polymer and wood fibers.

  19. Effect of gamma radiation on antioxidant capacity of green tea, yerba mate, and chamomile tea as evaluated by different methods

    NASA Astrophysics Data System (ADS)

    Gerolis, Luanai Grazieli Luquini; Lameiras, Fernando Soares; Krambrock, Klaus; Neves, Maria Jose.

    2017-01-01

    Tea is a traditional plant extract with important cultural ties. It is the most widely consumed beverage in the world. Tea consumption has some health benefits including antioxidant stimulus. Gamma radiation is currently used to control of postharvest pathogens on tea herb. However, free radicals can be generated, which consumes antioxidant molecules. A positive relation was found between radiation doses used and free radicals generation in green tea (Camellia sinensis), yerba mate (Ilex paraguariensis), and chamomile tea (Matricaria recutita). Total antioxidant capacity (TAC) of aqueous and methanol extracts of these herbs was determined by various methods to compare the effect of irradiation of herb on antioxidant capacity of the extracts. TAC was evaluated by measuring: total phenols (decreased with irradiation in mate and green teas), total flavonoids (stable in aqueous extracts and decreased with irradiation in methanol extract of mate and chamomile), Trolox equivalent or ABTS (unchanged under irradiation), DPPH* scavenging capacity (stable on aqueous extract but diminished in methanol extract after irradiation), β carotene/acid linoleic ability (stable with the exception of chamomile tea that increased after irradiation) and, capacity to chelate ferrous ions (unchanged with irradiation). In conclusion, gamma irradiation reduced the capacity of some antioxidants but preserved the capacity of others. This study showed that one isolated test does not suffice to perform this evaluation reliably, which is a reflection of the diversity and complexity of the effects of irradiation on antioxidant molecules present in different samples.

  20. Protective effects of melatonin and vitamin E in brain damage due to gamma radiation: an experimental study.

    PubMed

    Erol, Fatih S; Topsakal, Cahide; Ozveren, M Faik; Kaplan, Metin; Ilhan, Nevin; Ozercan, I Hanifi; Yildiz, Oguz G

    2004-01-01

    Gamma radiation is known to cause serious damage in the brain, and many agents have been used for neuroprotection. In this study, lipid peroxidation levels and histopathological changes in brain tissues of whole-body irradiated rats with likely radiation injury were compared to those with melatonin and vitamin E protection. Forty rats in four equal groups were used. The control group received neither radiation nor medication. The remaining groups received doses of 720 cGy in two equal fractions 12 h apart. The second group received radiation but no medication, the third received radiation plus 100 mg/kg per day of vitamin E i.p., and the fourth received radiation plus 100 mg/kg per day of melatonin i.p. over 5 days. On the 10th postoperative day, all the rats were decapitated and specimens from parietal cortices were analyzed for tissue malondialdehyde (MDA) levels and histopathological changes. Increases in MDA were relatively well prevented by melatonin treatment but less so with vitamin E therapy. On histopathological examination, melatonin significantly reduced the rates of edema, necrosis, and neuronal degeneration, whereas vitamin E reduced only necrosis. Neither substance was capable of preventing vasodilatation. In conclusion, melatonin may be useful in preventing the pathological changes of secondary brain damage as a result of free oxygen radicals generated by irradiation.

  1. Synthesis of β-Ca2P2O7:Tb(3+) to gamma radiation detection by thermoluminescence.

    PubMed

    Roman-Lopez, J; Lozano, I B; Cruz-Zaragoza, E; Castañeda, J I Guzman; Díaz-Góngora, J A I

    2017-03-06

    In this work, luminescent emissions of beta-calcium pyrophosphate doped with terbium ions (β-Ca2P2O7:Tb(3+)) were studied. The Ca2P2O7:Tb(3+) powders were prepared by precipitation and annealed at 900°C for 2h was applied on the powders to observe the beta phase. Radioluminescence measurements showed emission bands related with (5)D3 ((5)D4)→(7)FJ transitions of Tb(3+) ions. Three overlapped peaks at 126, 165 and 220°C were observed in thermoluminescence response. A linear TL dose-response in the range of 0.2-10Gy and an acceptable TL reproducibility were showed by the β-Ca2P2O7:Tb(3+) samples exposed to (60)Co gamma radiation. The TL glow curves were analyzed by Initial Rise method and Computational Glow-Curve Deconvolution assuming a General Order Kinetic model to evaluate the kinetic parameters related with the TL peaks.

  2. Assessment of mutagenic damage by monofunctional alkylating agents and gamma radiation in haploid and diploid frogs, Xenopus laevis

    SciTech Connect

    Hart, D.R.; Armstrong, J.B.

    1984-01-01

    Adult male South African clawed frogs, Xenopus laevis, were mutagenized by 3-day immersion in aqueous solutions of ethyl methanesulfonate (EMS), diethyl nitrosamine (DEN), or ethyl nitrosourea (ENU), or by acute exposure to gamma radiation. They were then spawned repeatedly at 2-week intervals with untreated females, and embryonic survival of the progeny was used to assess genetic damage. Recessive lethal effects were assessed from reduced survival of androgenetic haploid progeny. Neither recessive nor dominant lethal effects were obtained after exposure to 100 mg/liter EMS or 2 g/liter DEN. At 250 mg/liter EMS, peak dominant lethality occurred 3-5 weeks after treatment. Most embryos hatched, but many were abnormal and died shortly after hatching. Haploid survival was significantly reduced over a broader period, from 1 to 13 weeks after mutagenesis. Treatment with 75 mg/liter ENU produced effects similar to the 250-mg/liter EMS mutagenesis. At 400 mg/liter EMS, the frequency and severity of the effects on both diploid and haploid embryos were increased over the lower dose. Gamma irradiation at 1500 R produced effects similar to the 400-mg/liter mutagenesis, except that peak dominant lethality extended from 1 to 7 weeks.

  3. Chromosomal aberrations in peripheral blood lymphocytes exposed to a mixed beam of low energy neutrons and gamma radiation.

    PubMed

    Wojcik, A; Obe, G; Lisowska, H; Czub, J; Nievaart, V; Moss, R; Huiskamp, R; Sauerwein, W

    2012-09-01

    Cells exposed to thermal neutrons are simultaneously damaged by radiations with high and low linear energy transfer (LET). A question relevant for the assessment of risk of exposure to a mixed beam is whether the biological effect of both radiation types is additive or synergistic. The aim of the present investigation was to calculate whether the high and low LET components of a thermal neutron field interact when damaging cells. Human peripheral blood lymphocytes were exposed to neutrons from the HB11 beam at the Institute for Energy and Transport, Petten, Netherlands, in a 37 °C water phantom at varying depths, where the mix of high and low LET beam components differs. Chromosomal aberrations were analysed and the relative biological effectiveness (RBE) values as well as the expected contributions of protons and photons to the aberration yield were calculated based on a dose response of aberrations in lymphocytes exposed to (60)Co gamma radiation. The RBE for 10 dicentrics per 100 cells was 3 for mixed beam and 7.2 for protons. For 20 dicentrics per 100 cells the respective values were 2.4 and 5.8. Within the limitations of the experimental setup the results indicate that for this endpoint there is no synergism between the high and low LET radiations.

  4. Low Dose IR Creates an Oncogenic Microenvironment by Inducing Premature

    SciTech Connect

    Yuan, Zhi-Min

    2013-04-28

    Introduction Much of the work addressing ionizing radiation-induced cellular response has been carried out mainly with the traditional cell culture technique involving only one cell type, how cellular response to IR is influenced by the tissue microenvironment remains elusive. By use of a three-dimensional (3D) co-culture system to model critical interactions of different cell types with their neighbors and with their environment, we recently showed that low-dose IR-induced extracellular signaling via the tissue environment affects profoundly cellular responses. This proposal aims at determining the response of mammary epithelial cells in a tissue-like setting.

  5. LiCaAlF6 scintillators in neutron and gamma radiation fields

    NASA Astrophysics Data System (ADS)

    Viererbl, L.; Klupák, V.; Vinš, M.; Koleška, M.; Šoltés, J.; Yoshikawa, A.; Nikl, M.

    2016-09-01

    Intentionally doped LiCaAlF6 (LiCAF) single crystals are prospective scintillators, especially for thermal neutron detection through the 6Li(n,t)4He nuclear reaction. Four different LiCAF scintillator samples were tested in various neutron and gamma fields. Two of the tested samples were LiCAF:Eu and LiCAF:Eu,Na single crystals, and another two samples were made of LiCAF:Eu micro crystals dispersed in transparent rubber, with different rubber dimensions. All LiCAF samples contain lithium enriched to6Li. A plutonium-beryllium source was used as a neutron source. The neutron spectrum was modified by moderator and filter to get different ratios between thermal, epithermal and fast neutron fluence rates. The MCNP code was used for calculations of the fluence rates for different configurations. Radionuclides 137Cs and 60Co were applied as gamma radiation sources. The light signal from the scintillator was evaluated with a photomultiplier and a multichannel analyzer. The purpose of this work was to study the characteristics of LiCAF scintillators, especially the ability to discriminate signals from neutron and gamma radiation, which is the basic scintillator condition for neutron detection in mixed neutron-gamma radiation fields. Generally, the discrimination can be done by the pulse height and/or the pulse shape of the evaluated signals. Both methods can be used for a LiCAF scintillator. However, only the pulse height discrimination method is discussed in this paper. The possibility of fast neutron detection with LiCAF scintillators was also tested.

  6. Construction and validation of a dose-response curve using the comet assay to determine human radiosensitivity to ionizing radiation.

    PubMed

    Güerci, A; Zúñiga, L; Marcos, R

    2011-01-01

    Individual radiosensitivity is an individual characteristic associated with an increased reaction to ionizing radiation. The purpose of our work is to establish a dose-response curve useful to classify individuals as radiosensitive or radioresistant. Thus, a dose-response curve was constructed by measuring in vitro responses to increasing doses (0 to 8 Gy) of gamma radiation in the comet assay. The obtained curve fit well with a linear equation in the range of 0 to 8 Gy. The overall dose-response curve was constructed for percent DNA in tail, as a measure of the genetic damage induced by irradiation. To probe the goodness of the constructed curve, a validation study was carried out with whole blood from two donors in a blind study. Results show that, for the two applied doses (2 and 6 Gy), the obtained values fit well inside the interval of confidence of the curve. In conclusion, our results demonstrate the usefulness of the comet assay in determining individual responses to defined doses of gamma radiation. The standard dose-response curve constructed may be used to detect individuals departing from reference values.

  7. An Attempt to Measure the Gamma Radiation Dosage at Hiroshima from Photosensitive Material

    SciTech Connect

    Brixner, Berlyn; McmIllan, Edwin; Meade, Roger Allen

    2016-09-23

    After Japan surrendered in August 1945, a team of Los Alamos scientists entered both Hiroshima and Nagasaki to assess the damage of Little Boy and Fat Man. Two of these scientists, Berlyn Brixner and Edwin McMillan, discovered a stock of photographic film in Hiroshima that had been fogged by the gamma radiation from Little Boy. They devised an experiment that they thought might be used to determine the exposure levels in the city. Below is both their description of the film stock and the attempt to determine the exposure levels at Hiroshima.

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

    DOEpatents

    Condreva, K.J.

    1997-01-14

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

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

    DOEpatents

    Condreva, Kenneth J.

    1997-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  11. Operation Plumbbob. Program 2. Neutron and gamma radiation from Shot Laplace

    SciTech Connect

    Chiment, J.A.; Goetz, J.L.; Facer, G.C.

    1984-10-31

    The objectives of this experiment were to determine, for Shot Laplace, a 1.22-kt device fired late in Operation Plumbbob: (1) intensity and decay of the neuron-induced gammafield; (2) neutron flux and spectra as a function of distance; (3) neutron flux as a function of soil depth with certain selected detectors; and (4) neutron dose and initial gamma dose as a function of distance.

  12. Influence of gamma radiation on the colour strength and fastness properties of fabric using turmeric (Curcuma longa L .) as natural dye

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz A.; Adeel, Shahid; Jamal, M. Asghar; Safdar, Muhammad; Abbas, Muhammad

    2010-05-01

    The effect of gamma radiation on the dyeing of cotton with extract of turmeric ( Curcuma longa L.) powder has been investigated. Cotton fabric and turmeric powder were irradiated to absorbed doses of 1, 2, 3, 4 and 6 kGy using Co-60 gamma irradiator. Dyeing parameters such as temperature, pH and mordant concentration were optimized. Dyeing was performed using un-irradiated and irradiated cotton with the extracts of un-irradiated and irradiated turmeric powder in order to investigate the effect of radiation treatment on the colour strength of dyed fabric. The reported data of un-irradiated and irradiated fabrics dyed with un-irradiated and irradiated dyes were obtained using the spectraflash SF-650. The colourfastness to light, rubbing- and washing-fastness properties showed that gamma irradiation has improved the dyeing characteristics from fair to good.

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  14. Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

    NASA Technical Reports Server (NTRS)

    Chopra, Arsh; Ramirez, Gustavo A.; Venkateswaran, Kasthuri J.; Vaishampayan, Parag A.

    2011-01-01

    Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 mRad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

  15. Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

    NASA Technical Reports Server (NTRS)

    Chopra, Arsh; Ramirez, Gustavo A.; Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.

    2011-01-01

    Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 Mrad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

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

    NASA Technical Reports Server (NTRS)

    Peck, Eugene L.

    1992-01-01

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

  17. Response of organic liquid scintillators to fast neutrons and gamma radiation

    NASA Astrophysics Data System (ADS)

    Hoertz, Paul G.; Mills, Karmann; Davis, Lynn; Baldasaro, Nicholas; Gupta, Vijay

    2013-03-01

    Liquid organic scintillators are cocktails of aromatic fluorophores in an aromatic solvent. They find widespread use in Liquid Scintillation Counters with applications in medical diagnostics as well as fundamental nuclear and particle physics. Ultima Gold™ XR, a commercially available organic liquid scintillator from Perkin Elmer, can be used in both aqueous and non-aqueous systems and is typically used for beta detection in medical diagnostics. Its performance under gamma radiation and neutron radiation is less well-characterized. Special and normal Ultima Gold™ XR liquid scintillators were exposed in separate experiments to fast neutrons and high energy photons from a nuclear reactor and to gamma rays from a Co-60 source. To perform the measurements in the radiation chamber, a custom light collection system consisting of a fiber optic cable, spectrometer and a diffuse reflecting optical cavity was fabricated. Advanced calibration procedures, traceable to NIST standards, were developed to determine photon fluxes and flux densities of the scintillators under ionizing radiation conditions. The scintillator emission spectra under gamma radiation from a Co-60 source and neutron radiation from a pool-type nuclear reactor were recorded and compared. Results on the spectrometer design and comparison of the spectra under different exposure are presented.

  18. Gamma radiation and ozone sensing properties of In IIO 3:ZnO:SnO II thin films

    NASA Astrophysics Data System (ADS)

    Arshak, K.; Korostynska, O.; Hickey, G.

    2007-05-01

    This work explores the radiation and ozone sensing properties of mixed oxides in the form of thin films. External effects, such as radiation and ozone, cause defects in the materials it interacts with and, consequently, it causes changes in their properties. These changes manifest themselves as the alterations in both the electrical and the optical parameters, which are being measured and employed for dosimetry sensor development. An Edwards E306A thermal coating system was used for In IIO 3:ZnO:SnO II (90% : 5% : 5%) films deposition. For the electrical properties measurements, Cu electrodes were manufactured on the glass substrate via thermal evaporation of Cu; then AZ5214 photoresist was spin-coated over it and exposed to UV light via the acetate, containing the desired electrodes patterns. After the exposure, the substrate was placed in Electrolube PDN250ML developer solution and then rinsed in water and placed in the etching solution of SEMO 3207 fine etch crystals to reveal the electrode pattern. The optical properties of In IIO 3:ZnO:SnO II thin films were explored using CARY 1E UV-Visible Spectrophotometer. The values of the optical band gap E opt are estimated in the view of the Mott and Davis' theory. It was noted that E opt decreases with the increase in radiation dose, i.e. the overall disorder of the system is increased. Doping of In IIO 3 with 5% ZnO and 5% SnO II dramatically changes the overall structure of the film and thus affected its sensing to gamma radiation and ozone. Mixing metal oxides in certain proportions provides a tool for controlling the sensors response.

  19. Benchmark dose of lead inducing anemia at the workplace.

    PubMed

    Karita, Kanae; Yano, Eiji; Dakeishi, Miwako; Iwata, Toyoto; Murata, Katsuyuki

    2005-08-01

    To estimate the critical dose of lead inducing anemia in humans, the effects of lead on hemoglobin (Hb) and hematocrit (Hct) levels and red blood cell (RBC) count were examined in 388 male lead-exposed workers with blood lead (BPb) levels of 0.05-5.5 (mean 1.3) micromol/L by using the benchmark dose (BMD) approach. The BPb level was significantly related to Hb (regression coefficient beta=-0.276), RBC (beta=-11.35), and Hct (beta=-0.563) among the workers (p < 0.001) when controlling for age and working status. The average BPb levels were significantly higher in the workers with anemia (1.85 micromol/L), based on the WHO criteria, than in those without anemia (1.26 micromol/L). The benchmark dose levels of BPb (i.e., lower 95% confidence limits of BMD), calculated from the K-power model set at an abnormal probability of 5% in unexposed workers and an excess risk of 5% in exposed workers were estimated to be 0.94 micromol/L (19.5 microg/dl) for Hb, 0.94 micromol/L (19.4 microg/dl) for RBC, and 1.43 micromol/L (29.6 microg/dl) for Hct. These findings suggest that reduction in hematopoietic indicators may be initiated at BPbs below the level currently considered without effect.

  20. Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.

    PubMed

    Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

    2013-10-01

    This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere.

  1. Effects of gamma radiation on total phenolics, trypsin and tannin inhibitors in soybean grains

    NASA Astrophysics Data System (ADS)

    de Toledo, T. C. F.; Canniatti-Brazaca, S. G.; Arthur, V.; Piedade, S. M. S.

    2007-10-01

    The objective was determining possible radiation-induced alterations (with doses of 2, 4 and 8 kGy) in raw or cooked grains from five soybean cultivars through the analysis of some antinutrient. Total phenolic ranged from 2.46 to 10.83 mg/g, the trypsin inhibited from 18.19 to 71.64 UTI/g and tannins from 0.01 to 0.39 mg/g. All the antinutrient studied underwent reduction with increases in the doses and cooking process was effective too.

  2. Ferulic acid (FA) abrogates γ-radiation induced oxidative stress and DNA damage by up-regulating nuclear translocation of Nrf2 and activation of NHEJ pathway.

    PubMed

    Das, Ujjal; Manna, Krishnendu; Khan, Amitava; Sinha, Mahuya; Biswas, Sushobhan; Sengupta, Aaveri; Chakraborty, Anindita; Dey, Sanjit

    2017-01-01

    The present study was aimed to evaluate the radioprotective effect of ferulic acid (FA), a naturally occurring plant flavonoid in terms of DNA damage and damage related alterations of repair pathways by gamma radiation. FA was administered at a dose of 50 mg/kg body weight for five consecutive days prior to exposing the swiss albino mice to a single dose of 10 Gy gamma radiation. Ionising radiation induces oxidative damage manifested by decreased expression of Cu, Zn-SOD (SOD stands for super oxide dismutase), Mn-SOD and catalase. Gamma radiation promulgated reactive oxygen species (ROS) mediated DNA damage and modified repair pathways. ROS enhanced nuclear translocation of p53, activated ATM (ataxia telangiectasia-mutated protein), increased expression of GADD45a (growth arrest and DNA-damage-inducible protein) gene and inactivated Non homologous end joining (NHEJ) repair pathway. The comet formation in irradiated mice peripheral blood mononuclear cells (PBMC) reiterated the DNA damage in IR exposed groups. FA pretreatment significantly prevented the comet formation and regulated the nuclear translocation of p53, inhibited ATM activation and expression of GADD45a gene. FA promoted the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and activated NHEJ repair pathway to overcome ROS mediated oxidative stress and DNA damage. Therefore, the current study stated that FA can challenge the oxidative stress by (i) inducing nuclear translocation of Nrf2, (ii) scavenging ROS, and (iii) activating NHEJ DNA repair process.

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

    NASA Astrophysics Data System (ADS)

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

    2005-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Gosselin, P.; Charbonneau, R.

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

  5. Hemostatic potential of natural/synthetic polymer based hydrogels crosslinked by gamma radiation

    NASA Astrophysics Data System (ADS)

    Barba, Bin Jeremiah D.; Tranquilan-Aranilla, Charito; Abad, Lucille V.

    2016-01-01

    Various raw materials and hydrogels prepared from their combination were assessed for hemostatic capability using swine whole blood clotting analysis. Initial screening showed efficient coagulative properties from κ-carrageenan and its carboxymethylated form, and α-chitosan, even compared to commercial products like QuikClot Zeolite Powder. Blending natural and synthetic polymers formed into hydrogels using gamma radiation produced materials with improved properties. KC and CMKC hydrogels were found to have the lowest blood clotting index in granulated form and had the higher capacity for platelet adhesion in foamed form compared to GelFoam. Possible mechanisms involved in the evident thrombogenicity of the materials include adsorption of platelets and related proteins that aid in platelet activation (primary hemostasis), absorption of water to concentrate protein factors that control the coagulation cascade, contact activation by its negatively charged surface and the formation of gel-blood clots.

  6. The effect of gamma radiation on some succinic acid derivatives in the solid state

    NASA Astrophysics Data System (ADS)

    Sütçü, Kerem; Osmanoǧlu, Y. Emre

    2017-01-01

    2,2-dimethyl succinic acid, 2,3-dimethyl succinic acid and monomethyl succinate were exposed to gamma radiation in the form of powder. EPR measurements were carried out to investigate the free radicals produced in all of them, following irradiation. Three of the radical species formed after irradiation were identified and spectroscopic parameters were discussed thereafter. The radical species were attributed to the ĊHCH2, HOOCCH(CH3)2ĊCOOH and H3COOCCH2ĊHCOOH radicals, respectively. The hyperfine splitting constants for all radicals were confirmed by the simulation of the experimental spectra. The radiation sensitivity of the samples was mainly attributed to the EPR line properties of stable radicals.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  8. The effects of electron and gamma radiation on epoxy-based materials

    NASA Technical Reports Server (NTRS)

    Fornes, R. E.; Memory, J. D.; Gilbert, R. D.; Long, E. R., Jr.

    1982-01-01

    Specimens of graphite/epoxy composites and epoxy resins were exposed to electron and gamma radiation, followed by mechanical property and fundamental measurements. Measurement techniques included: scanning electron microscopy, X-ray diffraction analysis, and electron spin resonance spectroscopic analysis. Results indicate little or no change in flexural properties of miniature specimens of a graphite/epoxy composite and no change in failure mode at the fiber-resin interface and in the crystallinity of the fiber and the resin. Some doubt in the observation of stable flexural properties is cast by electron paramagnetic resonance spectra of a relatively large number of radiation-generated radicals. These generally lead to a change in cross-linking and in chain-scissioning which should alter mechanical properties.

  9. A new natural gamma radiation measurement system for marine sediment and rock analysis

    NASA Astrophysics Data System (ADS)

    Vasiliev, M. A.; Blum, P.; Chubarian, G.; Olsen, R.; Bennight, C.; Cobine, T.; Fackler, D.; Hastedt, M.; Houpt, D.; Mateo, Z.; Vasilieva, Y. B.

    2011-11-01

    A new high-efficiency and low-background system for the measurement of natural gamma radioactivity in marine sediment and rock cores retrieved from beneath the seabed was designed, built, and installed on the JOIDES Resolution research vessel. The system includes eight large NaI(Tl) detectors that measure adjacent intervals of the core simultaneously, maximizing counting times and minimizing statistical error for the limited measurement times available during drilling expeditions. Effect to background ratio is maximized with passive lead shielding, including both ordinary and low-activity lead. Large-area plastic scintillator active shielding filters background associated with the high-energy part of cosmic radiation. The new system has at least an order of magnitude higher statistical reliability and significantly enhances data quality compared to other offshore natural gamma radiation (NGR) systems designed to measure geological core samples. Reliable correlations and interpretations of cored intervals are possible at rates of a few counts per second.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

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

    NASA Technical Reports Server (NTRS)

    Moiseev, Alexander

    2008-01-01

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

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

    SciTech Connect

    Osterhuber, R.; Fehrke, F.; Condreva, K.

    1998-05-01

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

  13. Terrestrial gamma radiation baseline mapping using ultra low density sampling methods.

    PubMed

    Kleinschmidt, R; Watson, D

    2016-01-01

    Baseline terrestrial gamma radiation maps are indispensable for providing basic reference information that may be used in assessing the impact of a radiation related incident, performing epidemiological studies, remediating land contaminated with radioactive materials, assessment of land use applications and resource prospectivity. For a large land mass, such as Queensland, Australia (over 1.7 million km(2)), it is prohibitively expensive and practically difficult to undertake detailed in-situ radiometric surveys of this scale. It is proposed that an existing, ultra-low density sampling program already undertaken for the purpose of a nationwide soil survey project be utilised to develop a baseline terrestrial gamma radiation map. Geoelement data derived from the National Geochemistry Survey of Australia (NGSA) was used to construct a baseline terrestrial gamma air kerma rate map, delineated by major drainage catchments, for Queensland. Three drainage catchments (sampled at the catchment outlet) spanning low, medium and high radioelement concentrations were selected for validation of the methodology using radiometric techniques including in-situ measurements and soil sampling for high resolution gamma spectrometry, and comparative non-radiometric analysis. A Queensland mean terrestrial air kerma rate, as calculated from the NGSA outlet sediment uranium, thorium and potassium concentrations, of 49 ± 69 nGy h(-1) (n = 311, 3σ 99% confidence level) is proposed as being suitable for use as a generic terrestrial air kerma rate background range. Validation results indicate that catchment outlet measurements are representative of the range of results obtained across the catchment and that the NGSA geoelement data is suitable for calculation and mapping of terrestrial air kerma rate.

  14. Measuring the activity of a {sup 51}Cr neutrino source based on the gamma-radiation spectrum

    SciTech Connect

    Gorbachev, V. V. Gavrin, V. N.; Ibragimova, T. V.; Kalikhov, A. V.; Malyshkin, Yu. M.; Shikhin, A. A.

    2015-12-15

    A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of {sup 51}Cr is presented.

  15. Inactivation of Staphylococcus saprophyticus in chicken meat and exudate using high pressure processing, gamma radiation, and ultraviolet light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stapylococcus saprophyticus is a common contaminant in foods and causes urinary tract infections in humans. Three nonthermal food safety intervention technologies used to improve the safety foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). A...

  16. Preliminary results on soil-emitted gamma radiation and its relation with the local atmospheric electric field at Amieira (Portugal)

    NASA Astrophysics Data System (ADS)

    Lopes, F.; Silva, H. G.; Bárias, S.; Barbosa, S. M.

    2015-10-01

    The atmospheric electric field near the Earth's surface is dominated by atmospheric pollutants and natural radioactivity, with the latter directly linked to radon (222Rn) gas. For a better comprehension on the temporal variability of both the atmospheric electric field and the radon concentration and its relation with local atmospheric variables, simultaneous measurements of soil-emitted gamma radiation and potential gradient (defined from the vertical component of the atmospheric electric field) were taken every minute, along with local meteorological parameters (e.g., temperature, atmospheric pressure, relative humidity and daily solar radiation). The study region is Amieira, part of the Alqueva lake in Alentejo Portugal, where an interdisciplinary meteorological campaign, ALEX2014, took place from June to August 2014. Soil gamma radiation is more sensitive to small concentrations of radon as compared with alpha particles measurements, for that reason it is more suited for sites with low radon levels, as expected in this case. Preliminary results are presented here: statistical and spectral analysis show that i) the potential gradient has a stronger daily cycle as compared with the gamma radiation, ii) most of the energy of the gamma signal is concentrated in the low frequencies (close to 0), contrary to the potential gradient that has most of the energy in frequency 1 (daily cycle) and iii) a short-term relation between gamma radiation and the potential gradient has not been found. Future work and plans are also discussed.

  17. Effects of Hesperidin as a Radio-protector on Apoptosis in Rat Peripheral Blood Lymphocytes after Gamma Radiation

    PubMed Central

    Fardid, R.; Ghorbani*, Zh.; Haddadi, Gh.; Behzad-Behbahani, A.; Arabsolghar, R.; Kazemi, E.; Okhovat, M.A.; Hosseinimehr, S.J.

    2016-01-01

    Introduction: Hesperidin (HES), as the most abundant flavonoid existing in the citrus, is widely used by human daily. The radio-protective effects of Hesperidin have been confirmed in various measurement systems. This study aimed to evaluate the effects of Hesperidin on the changes in the apoptosis level and expression of apoptotic genes target (bax, bcl-2 and ration of bax/bcl-2) in the peripheral blood lymphocytes of male rats after gamma radiation. Materials and Methods: 64 male rats were divided into eight groups: Control, HES (100 mg/kg b.w, orally, 7 days), whole body irradiation with 2 and 8Gy, pre-administrated with 50 and 100 mg/kg body weight of Hesperidin for 7 days before irradiation with 2 and 8 Gy. 24 hours after radiation, apoptotic lymphocytes were evaluated using PE Annexin V Apoptosis detection I kit and the levels of mRNA for bax and bcl-2 were evaluated by real time reverse transcription polymerase chain reaction. Results: A significant reduction in apoptosis of the lymphocytes was demonstrated in group animals receiving 8 Gy compared to the group which received 2 Gy irradiation (p<0.0001). However, apoptosis significantly increased in group of rats who received Hesp before irradiation (p<0.05). The increase of apoptosis by Hesperidin administration can be attributed to the decreased expression of bax and significantly reduced expression of bcl-2 and finally increasing the ration of bax/bcl-2. Conclusion: The results suggest that administration of 50 and 100 mg/kg of Hesperidin induces apoptotic effects by changing expression level of bax, bcl-2 and also the ratio of bax/bcl2. PMID:28144590

  18. Adult myeloid leukaemia, geology, and domestic exposure to radon and gamma radiation: a case control study in central Italy

    PubMed Central

    Forastiere, F.; Sperati, A.; Cherubini, G.; Miceli, M.; Biggeri, A.; Axelson, O.

    1998-01-01

    OBJECTIVES: To investigate whether indoor randon or gamma radiation might play a part in myeloid leukaemia as suggested by studies based on crude geographical or geological data for exposure assessment. METHODS: For six months randon and gamma radiation was measured with solid state nuclear track detectors and thermoluminescent dosimeters in dwellings of 44 adult male cases of acute myeloid leukaemia and 211 controls (all subjects deceased). Conditional logistic regression ORs (ORs) and 95% confidence intervals (95% CIs) were estimated for quartiles of radon and gamma radiation and for municipality and dwelling characteristics. RESULTS: The risk of leukaemia was associated with an increasing urbanisation index (p value for trend = 0.008). An increased OR was found among those living in more modern houses (OR 3.0, 95% CI 1.4 to 6.6). Confirming the findings of a previous study in the same area, geological features bore a positive association with myeloid leukemia, even by adjusting for level of urbanisation. Contrary to expectations from the previous study, however, no association appeared between myeloid leukaemia and radon and gamma radiation; for the highest quartiles of exposure, ORs were 0.56 (95% CI 0.2 to 1.4) and 0.52 (95% CI 0.2 to 1.4), respectively. Considering only subjects who had lived > or = 20 years in the monitored home and adjusting for urbanisation, there was still no effect of exposure to radiation. CONCLUSIONS: In view of the limited numbers, the results do not in general refute a possible risk of myeloid leukaemia from exposure to indoor radon or gamma radiation, but decrease the credibility of such a relation in the area studied and also of other studies suggesting an effect without monitoring indoor radiation. Some other fairly strong determinants have appeared--that is, level of urbanisation and living in modern houses-- that might need further consideration.   PMID:9614394

  19. New model for assessing dose, dose rate, and temperature sensitivity of radiation-induced absorption in glasses

    SciTech Connect

    Gilard, Olivier; Quadri, Gianandrea; Caussanel, Matthieu; Duval, Herve; Reynaud, Francois

    2010-11-15

    A new theoretical approach is proposed to explain the dose, dose rate and temperature sensitivity of the radiation-induced absorption (RIA) in glasses. In this paper, a {beta}{sup th}-order dispersive kinetic model is used to simulate the growth of the density of color centers in irradiated glasses. This model yields an explanation for the power-law dependence on dose and dose rate usually observed for the RIA in optical fibers. It also leads to an Arrhenius-like relationship between the RIA and the glass temperature during irradiation. With a very limited number of adjustable parameters, the model succeeds in explaining, with a good agreement, the RIA growth of two different optical fiber references over wide ranges of dose, dose rate and temperature.

  20. Radioactivity of Tobacco Leaves and Radiation Dose Induced from Smoking

    PubMed Central

    Papastefanou, Constantin

    2009-01-01

    The radioactivity in tobacco leaves collected from 15 different regions of Greece and before cigarette production was studied in order to find out any association between the root uptake of radionuclides from soil ground by the tobacco plants and the effective dose induced to smokers from cigarette tobacco due to the naturally occurring primordial radionuclides, such as 226Ra and 210Pb of the uranium series and 228Ra of the thorium series and/or man-made radionuclides, such as 137Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the activities of the radioisotopes of radium, 226Ra and 228Ra in the tobacco leaves reflected their origin from the soil by root uptake rather than fertilizers used in the cultivation of tobacco plants. Lead-210 originated from the air and was deposited onto the tobacco leaves and trapped by the trichomes. Potassium-40 in the tobacco leaves was due to root uptake either from soil or from fertilizer. The cesium radioisotopes 137Cs and 134Cs in tobacco leaves were due to root uptake and not due to deposition onto the leaf foliage as they still remained in soil four years after the Chernobyl reactor accident, but were absent from the atmosphere because of the rain washout (precipitation) and gravitational settling. The annual effective dose due to inhalation for adults (smokers) for 226Ra varied from 42.5 to 178.6 μSv/y (average 79.7 μSv/y), while for 228Ra from 19.3 to 116.0 μSv/y (average 67.1 μSv/y) and for 210Pb from 47.0 to 134.9 μSv/y (average 104.7 μSv/y), that is the same order of magnitude for each radionuclide. The sum of the effective doses of the three radionuclides varied from 151.9 to 401.3 μSv/y (average 251.5 μSv/y). The annual effective dose from 137Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv/y (average 199.3 nSv/y). PMID:19440399

  1. Migration of dioctyladipate plasticizer from food-grade PVC film into chicken meat products: effect of gamma-radiation.

    PubMed

    Goulas, A E; Kontominas, M G

    1996-03-01

    Food-grade PVC film containing 28.3% dioctyladipate (DOA) plasticizer was used to wrap chicken meat samples, with and without skin, contained in a polystyrene tray. Samples were then irradiated with gamma-radiation [60Co] at doses equal to 4 kGy and 9 kGy corresponding to "cold pasteurization". Irraddiation was carried out at 8-10 degrees C and samples were subsequently stored at 4-5 degrees C. Contaminated chicken meat samples were analysed for DOA at intervals between 7 h and 240 h of contact, using an indirect GC method. Identical non-irradiated (control) samples were also analysed for their DOA content. Results showed no statistically significant differences in migrated amounts of DOA between irradiated and non-irradiated samples. Neither were differences observed between samples irradiated at 4 kGy and 9 kGy. This was supported by identical IR spectra recorded for irradiated and non-irradiated samples and leads to the conclusion that, at such intermediate radiation doses ( < or = kGy), the migration characteristics of PVC film are not affected. DOA migration was found to be time dependent, approaching equilibrium after approximately 170 h for the chicken flesh plus skin samples and 120 h for the chicken flesh samples. The amount of DOA migrated into chicken flesh plus skin samples was significantly greater (3.2-22.3 mg/dm2) than that for chicken flesh samples (0.9-8.9 mg/dm2). After 240 h of sample/film contact under refrigeration, loss of DOA was approximately 35.6% for chicken flesh plus skin samples and 14.3% for chicken flesh samples. Sample spoilage, as demonstrated by off-odour development, occurred after approximately 120 h of refrigerated storage. Diffusion coefficients for DOA were calculated and were found to be lower for chicken flesh (1 x 10(-13) than for flesh plus skin (4.4 x 10(-13)) samples.

  2. Morbidity and mortality reduction by supplemental vitamin A or beta-carotene in CBA mice given total-body gamma-radiation

    SciTech Connect

    Seifter, E.; Rettura, G.; Padawer, J.; Stratford, F.; Weinzweig, J.; Demetriou, A.A.; Levenson, S.M.

    1984-11-01

    Male CBA mice received graded doses (450-750 rad) of total-body gamma-radiation (TBR) from a dual-beam /sup 137/Cs irradiator. Commencing directly after TBR, 2 days later, or 6 days later, groups of mice received supplemental vitamin A (Vit A) or beta-carotene (beta-Car), compounds previously found to reduce radiation disease in mice subjected to partial-body X-irradiation. Given directly after TBR, supplemental Vit A decreased mortality, evidenced by increases in the radiation dose required to kill 50% of the mice within 30 days (LD50/30). In one experiment, Vit A increased the LD50/30 from 555 to 620 rad; in another experiment, Vit A increased the dose from 505 to 630 rad. Similarly, in a third experiment, supplemental beta-Car increased the LD50/30 from 510 to 645 rad. Additionally, each compound increased the survival times, even of those mice that died within 30 days. In addition to reduction of mortality and prolongation of survival time, supplemental Vit A moderated weight loss, adrenal gland hyperemia, thymus involution, and lymphopenia--all signs of radiation toxicity. Delaying the supplementation for 2 days after irradiation did not greatly reduce the efficacy of Vit A; however, delaying supplementation for 6 days decreased its effect almost completely.

  3. Induction of a Radio-Adaptive Response by Low-dose Gamma Irradiation in Mouse Cardiomyocytes

    NASA Technical Reports Server (NTRS)

    Westby, Christian M.; Seawright, John W.; Wu, Honglu

    2011-01-01

    One of the most significant occupational hazards to an astronaut is the frequent exposure to radiation. Commonly associated with increased risk for cancer related morbidity and mortality, radiation is also known to increase the risk for cardiovascular related disorders including: pericarditis, hypertension, and heart failure. It is believed that these radiation-induced disorders are a result of abnormal tissue remodeling. It is unknown whether radiation exposure promotes remodeling through fibrotic changes alone or in combination with programmed cell death. Furthermore, it is not known whether it is possible to mitigate the hazardous effects of radiation exposure. As such, we assessed the expression and mechanisms of radiation-induced tissue remodeling and potential radio-adaptive responses of p53-mediated apoptosis and fibrosis pathways along with markers for oxidative stress and inflammation in mice myocardium. 7 week old, male, C57Bl/6 mice were exposed to 6Gy (H) or 5cGy followed 24hr later with 6Gy (LH) 137Cs gamma radiation. Mice were sacrificed and their hearts extirpated 4, 24, or 72hr after final irradiation. Real Time - Polymerase Chain Reaction was used to evaluate target genes. Apoptotic genes Bad and Bax, pro-cell survival genes Bcl2 and Bcl2l2, fibrosis gene Vegfa, and oxidative stress genes Sod2 and GPx4 showed a reduced fold regulation change (Bad,-6.18; Bax,-6.94; Bcl2,-5.09; Bcl2l2,-4.03; Vegfa, -11.84; Sod2,-5.97; GPx4*,-28.72; * = Bonferroni adjusted p-value < or = 0.003) 4hr after H, but not after 4hr LH compared to control. Other p53-mediated apoptosis genes Casp3, Casp9, Trp53, and Myc exhibited down-regulation but did not achieve a notable level of significance 4hr after H. 24hr after H, genetic down-regulation was no longer present compared to 24hr control. These data suggest a general reduction in genetic expression 4hrs after a high dose of gamma radiation. However, pre-exposure to 5cGy gamma radiation appears to facilitate a radio

  4. Inactivation of Mycobacterium paratuberculosis and Mycobacterium tuberculosis in fresh soft cheese by gamma radiation

    NASA Astrophysics Data System (ADS)

    Badr, Hesham M.

    2011-11-01

    The effectiveness of gamma irradiation on the inactivation of Mycobacterium paratuberculosis, Mycobacterium bovis and Mycobacterium tuberculosis in fresh soft cheese that prepared from artificially inoculated milk samples was studied. Irradiation at dose of 2 kGy was sufficient for the complete inactivation of these mycobacteria as they were not detected in the treated samples during storage at 4±1 °C for 15 days. Moreover, irradiation of cheese samples, that were prepared from un-inoculated milk, at this effective dose had no significant effects on their gross composition and contents from riboflavin, niacin and pantothenic acid, while significant decreases in vitamin A and thiamin were observed. In addition, irradiation of cheese samples had no significant effects on their pH and nitrogen fractions contents, except for the contents of ammonia, which showed a slight, but significant, increases due to irradiation. The analysis of cheese fats indicated that irradiation treatment induced significant increase in their oxidation parameters and contents from free fatty acids; however, the observed increases were relatively low. On the other hand, irradiation of cheese samples induced no significant alterations on their sensory properties. Thus, irradiation dose of 2 kGy can be effectively applied to ensure the safety of soft cheese with regards to these harmful mycobacteria.

  5. Influence of gamma radiation on potato starch gelatinization studied by differential scanning calorimetry

    NASA Astrophysics Data System (ADS)

    Cieśla, Krystyna; Eliasson, Ann-Charlotte

    2002-05-01

    The paper presents a study of the influence of the conditions applied during differential scanning calorimetry (DSC) measurements (concentration and heating rate) on the possible detection of the differences between gelatinization occurring in both non-irradiated and irradiated potato starch with a dose of 20 kGy. Differences in gelatinization of irradiated and non-irradiated potato starch during DSC analysis was attributed to the radiation induced destruction of crystalline ordering. This was confirmed by studies of the samples irradiated to very high doses (446 and 600 kGy), and by comparing with the effect of grinding. Changes of starch properties caused by radiodepolymerization—contrary to those caused by grinding—influences gelatinization behaviour much more than the WAXS crystallinity in solid state.

  6. Stage specificity, dose response, and doubling dose for mouse minisatellite germ-line mutation induced by acute radiation.

    PubMed

    Dubrova, Y E; Plumb, M; Brown, J; Fennelly, J; Bois, P; Goodhead, D; Jeffreys, A J

    1998-05-26

    Germ-line mutation induction at mouse minisatellite loci by acute irradiation with x-rays was studied at premeiotic and postmeiotic stages of spermatogenesis. An elevated paternal mutation rate was found after irradiation of premeiotic spermatogonia and stem cells, whereas the frequency of minisatellite mutation after postmeiotic irradiation of spermatids was similar to that in control litters. In contrast, paternal irradiation did not affect the maternal mutation rate. A linear dose-response curve for paternal mutation induced at premeiotic stages was found, with a doubling dose of 0.33 Gy, a value close to those obtained in mice after acute spermatogonia irradiation using other systems for mutation detection. High frequencies of spontaneous and induced mutations at minisatellite loci allow mutation induction to be evaluated at low doses of exposure in very small population samples, which currently makes minisatellite DNA the most powerful tool for monitoring radiation-induced germ-line mutation.

  7. Strategy for stochastic dose-rate induced enhanced elimination of malignant tumour without dose escalation.

    PubMed

    Paul, Subhadip; Roy, Prasun Kumar

    2016-09-01

    The efficacy of radiation therapy, a primary modality of cancer treatment, depends in general upon the total radiation dose administered to the tumour during the course of therapy. Nevertheless, the delivered radiation also irradiates normal tissues and dose escalation procedure often increases the elimination of normal tissue as well. In this article, we have developed theoretical frameworks under the premise of linear-quadratic-linear (LQL) model using stochastic differential equation and Jensen's inequality for exploring the possibility of attending to the two therapeutic performance objectives in contraposition-increasing the elimination of prostate tumour cells and enhancing the relative sparing of normal tissue in fractionated radiation therapy, within a prescribed limit of total radiation dose. Our study predicts that stochastic temporal modulation in radiation dose-rate appreciably enhances prostate tumour cell elimination, without needing dose escalation in radiation therapy. However, constant higher dose-rate can also enhance the elimination of tumour cells. In this context, we have shown that the sparing of normal tissue with stochastic dose-rate is considerably more than the sparing of normal tissue with the equivalent constant higher dose-rate. Further, by contrasting the stochastic dose-rate effects under LQL and linear-quadratic (LQ) models, we have also shown that the LQ model over-estimates stochastic dose-rate effect in tumour and under-estimates the stochastic dose-rate effect in normal tissue. Our study indicates the possibility of utilizing stochastic modulation of radiation dose-rate for designing enhanced radiation therapy protocol for cancer.

  8. Myasthenic crisis and polymyositis induced by one dose of nivolumab.

    PubMed

    Kimura, Toshihiro; Fukushima, Satoshi; Miyashita, Azusa; Aoi, Jun; Jinnin, Masatoshi; Kosaka, Takayuki; Ando, Yukio; Matsukawa, Masakazu; Inoue, Hiroyuki; Kiyotani, Kazuma; Park, Jae-Hyun; Nakamura, Yusuke; Ihn, Hironobu

    2016-07-01

    An 80-year-old man, who developed multiple lymph node and skin metastasis of malignant melanoma, received nivolumab monotherapy. Two weeks after the first dose, he experienced anorexia and fatigue, and suffered from progressive, severe dyspnea and muscle weakness. We diagnosed him with myocarditis, myositis, and myasthenic crisis induced by nivolumab. We commenced steroid therapy, immune absorption therapy, plasma exchange therapy, and i.v. immunoglobulin therapy, and succeeded in saving his life. Because his serum level of anti-acetylcholine receptor antibodies in a sample collected before nivolumab treatment were positive and were elevated significantly after nivolumab, we suspected that nivolumab triggered a severe autoimmune response, which progressed subclinical myasthenia gravis to myasthenic crisis. We carried out T cell receptor repertoire analysis using next-generation sequencing technologies and identified infiltration of clonally expanded T cell populations in the skeletal muscle after nivolumab treatment, implying a very strong T cell immune response against muscular cells. To avoid severe immune-related adverse events, the exclusion of patients with subclinical autoimmune disease is very important for treatment with immune checkpoint inhibitors.

  9. Effect of 60Co-gamma radiation on the properties of furs

    NASA Astrophysics Data System (ADS)

    Raina, R. K.; Wali, B. K.; Wani, A. M.

    Furs pretanned with various combinations of vegetable tanning agents and retanned with alum have been irradiated with 60Co γ-radiation in the dose range 5.0-114.0 kGy. The physico-chemical modifications induced by the radiation have been assessed by measuring changes in tensile strength, absorption of water, elongation and shrinkage temperature. For investigations, samples have been taken from the same topographic region of the rabbit furs, belonging to the same age and sex. The results are discussed hereunder.

  10. Nanostructure of PDMS-TEOS-PrZr hybrids prepared by direct deposition of gamma radiation energy

    NASA Astrophysics Data System (ADS)

    Lancastre, Joana J. H.; Falcão, António N.; Margaça, Fernanda M. A.; Ferreira, Luís M.; Miranda Salvado, Isabel M.; Almásy, László; Casimiro, Maria H.; Meiszterics, Anikó

    2015-10-01

    Organic-inorganic materials have been the object of intense research due to their wide range of properties and therefore innumerous applications. We prepared organic-inorganic hybrid materials by direct energy deposition on a mixture of polydimethylsiloxane silanol terminated (33 wt% fixed content), tetraethylorthosilicate and a minor content of zirconium propoxide that varied from 1 to 5 wt% using gamma radiation from a Co-60 source. The samples, dried in air at room temperature, are bulk, flexible and transparent. Their nanostructure was investigated by small angle neutron scattering. It was found that the inorganic oxide network has fractal structure, which becomes denser as the zirconium propoxide content decreases. The results suggest that oxide nanosized regions grow from the OH terminal group of PDMS which are the condensation seeds. Their number and position remains unaltered with the variation of zirconium propoxide content that only affects their microstructure. A model is proposed for the nanostructure of the oxide network that develops in the irradiation processed hybrid materials.

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  12. Analysis of gamma radiation from a radon source: Indications of a solar influence

    NASA Astrophysics Data System (ADS)

    Sturrock, P. A.; Steinitz, G.; Fischbach, E.; Javorsek, D.; Jenkins, J. H.

    2012-08-01

    This article presents an analysis of about 29,000 measurements of gamma radiation associated with the decay of radon in a sealed container at the Geological Survey of Israel (GSI) Laboratory in Jerusalem between 28 January 2007 and 10 May 2010. These measurements exhibit strong variations in time of year and time of day, which may be due in part to environmental influences. However, time-series analysis reveals a number of periodicities, including two at approximately 11.2 year-1 and 12.5 year-1. We have previously found these oscillations in nuclear-decay data acquired at the Brookhaven National Laboratory and at the Physiklisch-Technische Bundesanstalt, and we have suggested that these oscillations are attributable to some form of solar radiation that has its origin in the deep solar interior. A curious property of the GSI data is that the annual oscillation is much stronger in daytime data than in nighttime data, but the opposite is true for all other oscillations. This may be a systematic effect but, if it is not, this property should help narrow the theoretical options for the mechanism responsible for decay-rate variability.

  13. An integrated systems approach for understanding cellular responses to gamma radiation.

    PubMed

    Whitehead, Kenia; Kish, Adrienne; Pan, Min; Kaur, Amardeep; Reiss, David J; King, Nichole; Hohmann, Laura; DiRuggiero, Jocelyne; Baliga, Nitin S

    2006-01-01

    Cellular response to stress entails complex mRNA and protein abundance changes, which translate into physiological adjustments to maintain homeostasis as well as to repair and minimize damage to cellular components. We have characterized the response of the halophilic archaeon Halobacterium salinarum NRC-1 to (60)Co ionizing gamma radiation in an effort to understand the correlation between genetic information processing and physiological change. The physiological response model we have constructed is based on integrated analysis of temporal changes in global mRNA and protein abundance along with protein-DNA interactions and evolutionarily conserved functional associations. This systems view reveals cooperation among several cellular processes including DNA repair, increased protein turnover, apparent shifts in metabolism to favor nucleotide biosynthesis and an overall effort to repair oxidative damage. Further, we demonstrate the importance of time dimension while correlating mRNA and protein levels and suggest that steady-state comparisons may be misleading while assessing dynamics of genetic information processing across transcription and translation.

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

    SciTech Connect

    Gano, K.A.

    1981-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

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

    PubMed

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

    2011-10-01

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

  17. Sensitivity of Roberts Syndrome Cells to gamma radiation, mitomycin C, and protein synthesis inhibitors

    SciTech Connect

    Van Den Berg, D.J.; Francke, U. )

    1993-07-01

    Roberts syndrome (RS) is a rare autosomal recessive disorder characterized by pre- and postnatal growth retardation, limb reduction abnormalities, and craniofacial anomalies. Mitotic chromosomes from RS individuals display repulsion of heterochromatin regions or centromere splitting, leading to a railroad-track appearance of mitotic chromosomes. Abnormalities in metaphase duration, anaphase progression, nuclear morphology, and increased frequency of micronucleation have been reported in RS cells. Cells from RS heterozygotes are normal in these respects, and in vitro complementation of the defects in somatic cell hybrids has been reported. Therefore, in preparation for the isolation of cDNAs that complement the RS defect, the authors investigated various drug treatments to identify an agent that specifically involves the growth of RS cells. Based on the cytogenetic and cell biologic findings, they chose agents that increase micronucleation or inhibit protein synthesis. They found that RS cells are hypersensitive to gamma radiation, mitomycin C, G418 and hygromycin B, but not to colcemid or streptonigrin when compared to normal cells. DNA content and cell viability analysis confirmed that the sensitivity to gamma irradiation was primarily due to increased cell death.

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

    SciTech Connect

    Gano, K.A.

    1981-01-01

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

  19. Size Effects on Gamma Radiation Response of Magnetic Properties of Barium Hexaferrite Powders

    SciTech Connect

    McCloy, John S.; Kukkadapu, Ravi K.; Crum, Jarrod V.; Johnson, Bradley R.; Droubay, Timothy C.

    2011-12-08

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

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  1. Chromosome fragility in New Zealand black mice: effect of ultraviolet and gamma radiations on fetal fibroblasts in vitro

    SciTech Connect

    Reddy, A.L.; Fialkow, P.J.

    1980-04-01

    The sensitivity of fibroblasts cultured from New Zealand Black (NZB) and BALB/c mouse fetuses to uv and gamma radiations was tested with two methods: (1) colony-forming ability and (2) chromosome abnormalities. When compared with BALB/c cells, NZB cells had reduced colony-forming ability and increased chromosome abnormalities after uv irradiation. However, no differences were seen in colony formation or frequency of chromosome abnormalities between NZB and BALB/c cells after exposure to gamma radiation. This apparent uv specificity strengthens the suggestion that NZB mice might be used as a model to study the relationship between chromosome abnormalities and cancer in human syndromes such as xeroderma pigmentosum, which is characterized by chromosome instability.

  2. Gamma radiation impact on performance of OOK, DPSK and homodyne BPSK based optical inter-satellite communication system

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Hou, Rui; Qiang, Ruoxin

    2015-09-01

    Performance of optical inter-satellite communication system is influenced by the harsh space radiation environment. Gamma radiation effects on main devices of communication system are analyzed and on the basis of existing experimental data, performance degradation of on off keying (OOK), differential phase shift keying (DPSK) and homodyne binary phase shift keying (BPSK) based system under 1 kGy gamma irradiation is simulated. Variation of Q factors and bit error ratio of these systems with different radiation position are achieved and discussed. The result shows that it is more urgent to improve the radiation hardness of transmitter, and the introduction of local laser is a considerable method to reduce gamma radiation impact on system performance.

  3. [The effectiveness of fractionated exposure of sarcoma M-1 to gamma-radiation and fast neutrons].

    PubMed

    Iuzhakov, V V; Sevan'kaeva, L E; Ul'ianenko, S E; Iakovleva, N D; Kuznetsova, M N; Tsyganova, M G; Fomina, N K; Ingel', I E; Lychagin, A A

    2013-01-01

    The effectiveness of fractionated exposure to gamma- and neutron radiation in their separate and combined use on the growth and functional morphology of mutant p53 sarcoma M-1 in rats was studied. Investigation techniques included immunostaining of PCNA and mutant p53 expressing cells, determination of mitotic activity and apoptotic death of tumor cells, as well as computer analysis of microscopic images. The antitumor efficacy of different types of radiation is shown to be determined by different levels of apoptosis induction, reduced proliferation and cellularity. Neutron radiation of the impulse generator has a marked damaging effect on the vasculature and the development of tumor necrosis. Fractionated irradiation at equal daily doses led to the decrease in the relative effectiveness of radio-inactivation of tumor cells. After 9 fractions of irradiation, the calculated value of the RBE of fast neutrons normalized to the input dose of 1 Gy by the coefficient of tumor growth inhibition, a reduced proliferative activity of PCNA and induced apoptosis of tumor cells was 3.4, 3.7 and 3.1, respectively. In the mode of daily superfractionation with splitting the dose in two fractions, the effectiveness of the combined exposure corresponded to the additive effect of gamma- and neutron radiation with a tendency toward synergism. There are reasons to believe that high resistance of sarcoma M-1 to the ionizing radiation impact is due not only to a fraction of hypoxic cells, but also the mutant status of p53 gene.

  4. Improving Low-Dose Blood-Brain Barrier Permeability Quantification Using Sparse High-Dose Induced Prior for Patlak Model

    PubMed Central

    Fang, Ruogu; Karlsson, Kolbeinn; Chen, Tsuhan; Sanelli, Pina C.

    2014-01-01

    Blood-brain-barrier permeability (BBBP) measurements extracted from the perfusion computed tomography (PCT) using the Patlak model can be a valuable indicator to predict hemorrhagic transformation in patients with acute stroke. Unfortunately, the standard Patlak model based PCT requires excessive radiation exposure, which raised attention on radiation safety. Minimizing radiation dose is of high value in clinical practice but can degrade the image quality due to the introduced severe noise. The purpose of this work is to construct high quality BBBP maps from low-dose PCT data by using the brain structural similarity between different individuals and the relations between the high- and low-dose maps. The proposed sparse high-dose induced (shd-Patlak) model performs by building a high-dose induced prior for the Patlak model with a set of location adaptive dictionaries, followed by an optimized estimation of BBBP map with the prior regularized Patlak model. Evaluation with the simulated low-dose clinical brain PCT datasets clearly demonstrate that the shd-Patlak model can achieve more significant gains than the standard Patlak model with improved visual quality, higher fidelity to the gold standard and more accurate details for clinical analysis. PMID:24200529

  5. Improving low-dose blood-brain barrier permeability quantification using sparse high-dose induced prior for Patlak model.

    PubMed

    Fang, Ruogu; Karlsson, Kolbeinn; Chen, Tsuhan; Sanelli, Pina C

    2014-08-01

    Blood-brain barrier permeability (BBBP) measurements extracted from the perfusion computed tomography (PCT) using the Patlak model can be a valuable indicator to predict hemorrhagic transformation in patients with acute stroke. Unfortunately, the standard Patlak model based PCT requires excessive radiation exposure, which raised attention on radiation safety. Minimizing radiation dose is of high value in clinical practice but can degrade the image quality due to the introduced severe noise. The purpose of this work is to construct high quality BBBP maps from low-dose PCT data by using the brain structural similarity between different individuals and the relations between the high- and low-dose maps. The proposed sparse high-dose induced (shd-Patlak) model performs by building a high-dose induced prior for the Patlak model with a set of location adaptive dictionaries, followed by an optimized estimation of BBBP map with the prior regularized Patlak model. Evaluation with the simulated low-dose clinical brain PCT datasets clearly demonstrate that the shd-Patlak model can achieve more significant gains than the standard Patlak model with improved visual quality, higher fidelity to the gold standard and more accurate details for clinical analysis.

  6. Prevention of Gamma Radiation-Induced Mortality in Mice by the Isoflavone Genistein

    DTIC Science & Technology

    2005-01-01

    activity, grip strength, body weight, testes weight, or histopathology. The results demonstrate that a single subcutane- ous administration of the flavonoid ...occurring isoflavone found in soybeans, has gained increas- ing attention because of its association with beneficial effects for treatment of cardiovascular ...693-694. [Erlejman 2004] A.G. Erlejman, S.V. Verstraeten, C.G. Fraga, P.I. Oteiza, The interaction of flavonoids with membranes: potential

  7. Gamma radiation induced background determination for (n,γ) measurements with 4π detectors.

    SciTech Connect

    Reifarth, R.; Browne, J. C.; Esch, E. I.; Haight, R. C.; O'Donnell, J. M.; Kronenberg, A.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Greife, U.

    2003-07-29

    The main focus of this report is to investigate possibilities to disentangle the target originating γ- background from background caused by scattered neutrons at the sample assuming a DANCE like detector to measure detect the capture events.

  8. Gamma-radiation-induced dielectric relaxation characteristics of layered crystals of phlogopite mica

    NASA Astrophysics Data System (ADS)

    Kaur, Navjeet; Singh, Mohan; Singh, Lakhwant; Awasthi, A. M.; Kumar, Jitender

    2013-12-01

    In the present investigation, the influence of gamma irradiation on the dielectric relaxation characteristics of phlogopite mica was studied over the frequency range of 0.1 Hz-10 MHz and in the temperature range of 593-813 K by measuring the dielectric permittivity, electric modulus and conductivity. By comparing the dielectric spectra obtained for pristine and irradiated samples, it was observed that gamma irradiation significantly enhances the dielectric constants (ɛ‧ and ɛ″) of phlogopite mica because of the production of defects and lattice disorder by the gamma irradiation. The values of the activation energy for pristine and irradiated mica (determined from the electric modulus and the conductivity) were found to be substantially similar, suggesting that the same types of charge carriers are involved in the relaxation mechanism. The experimentally measured electric modulus and conductivity data could be well interpreted by the Havriliak-Negami dielectric relaxation function. The scaling of the electric-modulus spectra of both pristine and irradiated mica results in a master curve, which indicates that the relaxation mechanism is independent of temperature. Cole-Cole plots were also employed to analyze the non-Debye relaxation mechanism. This research will boost the reader's interest concerning the emerging contributions of irradiation and materials such as mica in electrical engineering.

  9. High dose of ascorbic acid induces cell death in mesothelioma cells.

    PubMed

    Takemura, Yukitoshi; Satoh, Motohiko; Satoh, Kiyotoshi; Hamada, Hironobu; Sekido, Yoshitaka; Kubota, Shunichiro

    2010-04-02

    Malignant mesothelioma is an asbestos-related fatal disease with no effective cure. Recently, high dose of ascorbate in cancer treatment has been reexamined. We studied whether high dose of ascorbic acid induced cell death of four human mesothelioma cell lines. High dose of ascorbic acid induced cell death of all mesothelioma cell lines in a dose-dependent manner. We further clarified the cell killing mechanism that ascorbic acid induced reactive oxygen species and impaired mitochondrial membrane potential. In vivo experiment, intravenous administration of ascorbic acid significantly decreased the growth rate of mesothelioma tumor inoculated in mice. These data suggest that ascorbic acid may have benefits for patients with mesothelioma.

  10. Improvement of physico-mechanical, thermomechanical, thermal and degradation properties of PCL/gelatin biocomposites: Effect of gamma radiation

    NASA Astrophysics Data System (ADS)

    Zaman, Haydar U.; Beg, M. D. H.

    2015-04-01

    This research was to study the effects of gelatin content variation and gamma radiation after the 2-ethylhexyl acrylate (EHA) pre-treatment on the foundamental properties of gelatin film laminated polycaprolactone (PCL) biocomposites. PCL/gelatin film (PCL/GF) composites were fabricated by compression molding and their properties were studied by physico-mechanical, thermomechanical, thermal and degradation properties. The results from mechanical properties such as tensile modulus and impact strength of the composites increased with increasing of gelatin content up to 10 wt% and then decreased while the tensile strength and elongation at break decreased. EHA monomer (2-8 wt%) was added to the gelatin solution and films were prepared by casting and found to increase the mechanical properties of the PCL/EHA blended gelatin film (PCL/EGF) composites. Treatment of the gelatin film with gamma radiation after the EHA pre-treatment showed the best mechanical properties of the resulting composites. Dynamic mechanical thermal analysis results showed that the storage modulus of the PCL/EGF and PCL/EHA blended gelatin film with gamma radiation (PCL/GEGF) composites was increased significantly. The degradation properties in water and soil were determined for the non-irradiated and irradiated composites. It was observed that the non-irradiated composite degrades more than that of the irradiated composites.

  11. Acute quetiapine dose-dependently exacerbates anhedonia induced by withdrawal from escalating doses of d-amphetamine.

    PubMed

    Zhornitsky, Simon; Potvin, Stéphane; Stip, Emmanuel; Rompré, Pierre-Paul

    2010-10-01

    Recent clinical studies show that the atypical antipsychotic medication, quetiapine, may be beneficial in the treatment of substance abuse by alleviating the withdrawal-negative affect stage of addiction. Since the effect of quetiapine on central reward function is largely unknown we studied its effects on brain stimulation reward in animals under withdrawal from escalating doses of d-amphetamine. Male Sprague-Dawley rats were trained to produce an operant response to receive a short train of electrical stimulation to the lateral hypothalamus. Measures of reward threshold were determined with the curve-shift method in different groups of rats before, and during four days after treatment with escalating doses (1 to 10mg/kg, i.p.) of d-amphetamine or its vehicle. At 24h of withdrawal, the effects of two doses of quetiapine (2 and 10mg/kg i.p.) were tested. Animals treated with d-amphetamine showed a 25% reward deficit at 24h of withdrawal, an effect that decreased progressively over the next three days. Quetiapine attenuated reward in the vehicle-control animals, and amplified the anhedonia at the moderate, but not the low, dose in the animals under withdrawal. These results show that acute treatment with clinically relevant doses of quetiapine for the treatment of schizophrenia may exacerbate anhedonia induced by amphetamine withdrawal. Further research should investigate whether repeated treatment with quetiapine has the ability to reverse amphetamine withdrawal-induced anhedonia.

  12. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding

    NASA Technical Reports Server (NTRS)

    George, K.; Willingham, V.; Wu, H.; Gridley, D.; Nelson, G.; Cucinotta, F. A.

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  13. Chromosome aberrations in human lymphocytes induced by 250 MeV protons: effects of dose, dose rate and shielding.

    PubMed

    George, K; Willingham, V; Wu, H; Gridley, D; Nelson, G; Cucinotta, F A

    2002-01-01

    Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm2 aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples.

  14. [The advance of model of action in low-dose chronic benzene exposure induced hematotoxicity].

    PubMed

    Gao, Chen; Zhang, Zhengbao; Chen, Liping; Chen, Wen

    2015-09-01

    Benzene is classified as Group 1 carcinogen by IARC. It has been found that benzene induces hematotoxicity even in low dose exposure. The identification of key events during benzene induced hematotoxicty leads to adjustment of occupational exposure limits of benzene. In this review, we focus on the exposure, metabolism, target organs, key epigenetic changes, toxicty effects and end points of low-dose chronic benzene exposure induced hematotoxicity and finally discuss the perspectives on the future study of this area.

  15. A study of neutron and gamma radiation effects on transmission of various types of glasses, optical coatings, cemented optics and fiber

    NASA Astrophysics Data System (ADS)

    Javed Akhtar, S. M.; Ashraf, Mohammad; Khan, Shaukat Hameed

    2007-08-01

    A study of radiation effects on various types of glasses, dielectric optical coatings, cemented optics and fiber was undertaken with a view to select them for extreme radiation environments. Samples were exposed to different radiation doses in the Pakistan Research Reactor-I (PARR-I) for neutron and Cobalt 60 source for gamma irradiation. Transmissions were measured before and after irradiation. The dielectric coatings were subjected to additional tests (adhesion, abrasion and humidity, etc.) as per MIL-M-13508C and MIL-C-675C. All 15 glasses studied showed varying amounts of transmission loss as expected, with negligible degradation for three types. Recovery of transmissions with time/ageing was also studied, with more or less complete recovery with temperature annealing. A faster bleaching of darkened/brown glasses was achieved by using UV lamps or UV laser. The dielectric coatings (HR, AR) and one of the two commercial optical cements showed excellent resistance to neutrons and gamma radiations, and could be good candidates for the fabrication and utilization of optical components in extreme radiation environments. The data allowed several Chinese glasses to be studied for the first time.

  16. Gamma radiation effect on structural properties of PLLA/PCL blends

    NASA Astrophysics Data System (ADS)

    Kodama, Y.; Machado, L. D. B.; Giovedi, C.; Nakayama, K.

    2007-12-01

    Poly(L-lactic acid) (PLLA) and poly(ɛ-caprolactone) (PCL) extruded homopolymers and PLLA/PCL blends films were irradiated with gamma rays from Co-60 at doses in the range of 25-500 kGy to investigate the effect of the ionizing radiation on the morphological properties of the samples. The morphology of the homopolymers and the blends were observed by scanning electron microscope (SEM). The micrographs of the fractured homopolymers and blends have shown immiscibility of the blends. The crystallization of PLLA can be observed in the annealed samples. Samples irradiated with 100 kGy presented few variations in the morphology. But in PCL homopolymer and PCL/PLLA 50/50 wt% blend irradiated with 500 kGy dose it was possible to observe significant alteration. The ruptured sample surface of irradiated PCL with 500 kGy became full of scales probably due to an increase of crosslinking density induced by the ionizing radiation, but apparently no changes promoted by ionizing radiation could be observed on the irradiated PLLA by SEM.

  17. Diverse delayed effects in human lymphoblastoid cells surviving exposure to high-LET (56)Fe particles or low-LET (137)Cs gamma radiation

    NASA Technical Reports Server (NTRS)

    Evans, H. H.; Horng, M. F.; Ricanati, M.; Diaz-Insua, M.; Jordan, R.; Schwartz, J. L.

    2001-01-01

    To obtain information on the origin of radiation-induced genomic instability, we characterized a total of 166 clones that survived exposure to (56)Fe particles or (137)Cs gamma radiation, isolated approximately 36 generations after exposure, along with their respective control clones. Cytogenetic aberrations, growth alterations, responses to a second irradiation, and mutant frequencies at the Na(+)/K(+) ATPase and thymidine kinase loci were determined. A greater percentage of clones that survived exposure to (56)Fe particles exhibited instability (defined as clones showing one or more outlying characteristics) than in the case of those that survived gamma irradiation. The phenotypes of the unstable clones that survived exposure to (56)Fe particles were also qualitatively different from those of the clones that survived gamma irradiation. A greater percentage (20%) of the unstable clones that survived gamma irradiation than those that survived exposure to (56)Fe particles (4%) showed an altered response to the second irradiation, while an increase in the percentage of clones that had an outlying frequency of ouabain-resistant and thymidine kinase mutants was more evident in the clones exposed to (56)Fe particles than in those exposed to gamma rays. Growth alterations and increases in dicentric chromosomes were found only in clones with more than one alteration. These results underscore the complex nature of genomic instability and the likelihood that radiation-induced genomic instability arises from different original events.

  18. Induction of sterility in Anastrepha Fraterculus (Diptera: Tephritidae) by gamma radiation

    SciTech Connect

    Allinghi, A.; Gramajo, C.; Willink, E.; Vilardi, J.

    2007-03-15

    In relation to the application of the sterile insect technique (SIT) for the South American fruit fly Anastrepha fraterculus (Wiedemann), we analyzed the effect on adult fertility of different doses of gamma irradiation and the age of pupae at the time of irradiation. In a first experiment, we applied doses of 50, 70, and 90 Gy to pupae at 24, 48, 72, and 96 h before adult emergence. In a second experiment we irradiated pupae 48 h before emergence with 20, 40, and 60 Gy and estimated male and female fertility and sperm transfer by irradiated males. The results indicated pupal age at irradiation does not significantly affect male fertility. If males irradiated with 60 Gy are crossed to non-irradiated females the fertility is about 1%. Females irradiated with 40 Gy did not lay eggs independently of the male to which they mated. No significant effects of radiation were observed with respect to the ability of males to transfer sperm. A dose of 70 Gy applied 48 h before adult emergence induces 100% sterility in both males and females. (author) [Spanish] Para la aplicacion de la tecnica del insecto esteril (TIE) en Anastrepha fraterculus (Wiedemann), en este trabajo analizamos el efecto de diferentes dosis de irradiacion gamma y la edad optima de la pupa al momento de la irradiacion. En el primer experimento se evaluaron las dosis de 50, 70, y 90 Gy en pupas de 24, 48, 72, y 96 h antes de la emergencia del adulto. En el segundo experimento se irradiaron pupas 48 h antes de la emergencia con dosis de 20, 40, 60 Gy y se estimo la fertilidad de los machos y las hembras, y la transferencia de espermas por los machos irradiados. Los resultados indicaron que la irradiacion no modifico significativamente la fertilidad de los machos. En las cruzas de machos irradiados a 60 Gy con hembras no irradiadas se observo 1% de eclosion larvaria, mientras que las hembras irradiadas a 40 Gy no pusieron huevos. La irradiacion no afecto significativamente la transferencia de espermas de los

  19. Use of gamma radiation as a form of preservation of sweet potatoes: Phase 2: Final report for period January 1, 1986-December 31, 1986

    SciTech Connect

    Tolbert, M.E.M.; Loretan, P.A.

    1987-04-01

    Effects of gamma radiation and storage time on storage roots of 'Georgia Jet' and 'Jewel' sweet potatoes and on the sweetpotato weevil Cylas formicarius elegantulus (Summers) were studied. The storage roots were irradiated: immediately after harvest and before curing immediately after curing, or after curing plus three months of storage. Storage was at 14 to 16/sup 0/C with 85 to 90% relative humidity. Sweet potatoes were examined at different stages of storage over nine months for sprouting, storage rot development, flesh color, texture, moisture, carbohydrates, starch granules - cell ultrastructure, ascorbic acid, enzyme activity, peroxidase and polyphenol oxidase, protein and organoleptic properties. It was found that sweet potatoes should never be irradiated prior to curing since increased rotting results. No significant difference was found in storage rot development between control and irradiated after curing at doses up to 0.20 kGy. Nutritive components were in most cases not significantly affected by radiation at the four doses studies. Nutritive qualities of moisture, texture, starch, ascorbic acid, sugar, color and enzymes all changed to one extent or another with increased storage time. Irradiation speeds up the process of cell wall collapse and accumulation of cytoplasmic debris, but this also occurs later in the control. Isoelectric focusing results demonstrate that radiation effects on proteins are very small up to a dose of 0.20 kGy. HPLC results indicated that irradiation of the roots caused accumulation of new proteins while impairing the formation of others. Fecundity of the sweetpotato weevil was reduced at 15/sup 0/C compared to 28/sup 0/C.

  20. Assessment of organochlorine hydrocarbons transformation in contaminated agricultural products and foodstuffs under gamma-radiation

    NASA Astrophysics Data System (ADS)

    Mel’nikova, T. V.; Polyakova, L. P.; Oudalova, A. A.

    2017-01-01

    The problem of an estimation of organochlorinated pollutants transformation (particularly organochlorinated pesticides (OCP) and polychlorinated biphenyls (PCB)) under gamma-irradiation has become important in connection with radiation technologies application in the food industry. According to earlier researches, small doses of OCP lead to serious damages of an organism, comparable with damages from high doses. Among radiolysis products of OCP in model solutions various substances on a structure have been found out. Though of trace concentration of each of them, in sum with the initial pesticides residue they make up significant of mass contamination (as shown earlier up to 90% from initial OCP). In this work fish samples (bream) containing OCPs (15.20 ng/g of hexachlorocyclohexane isomers and 87.10 ng/g of DDT and its metabolites), as well as PCB (18.51 ng/g) were studied. The minced fish was irradiated at dose of 10 kGy with dose rate of 1.35 Gy/sec. Then, by methods of gas-liquid chromatography (GLC) and gas chromatography-mass spectrometry (GC-MS), it was found that the OCPs degradation varied from 3 up to 61% and the PCB degradation – 24-52%. Significant complication of chemical composition was shown comparing to the primary biological sample contamination. As a result of fish irradiation, secondary pollution appeared that included residues of primary organochlorine hydrocarbons and their radiation-induced metabolites. Among the investigated OCPs the most stable proved to be alfa-hexachlorocyclohexane (alfa-HCH), the least stable – DDT which corresponds to the previous findings about the radiation stability of OCPs in model solutions. Mass spectra of the irradiated samples of minced bream showed the presence of radiation metabolites of OCPs, that had also been found at irradiation of model solutions of 2,2-di(4-chlorophenyl)-1-chlorethylene (DDMU), DDD and 1a, 2e, 3e, 4e, 5e-pentahlorcyclohexane. There was revealed a decomposition product formed during

  1. Pb low doses induced genotoxicity in Lactuca sativa plants.

    PubMed

    Silva, S; Silva, P; Oliveira, H; Gaivão, I; Matos, M; Pinto-Carnide, O; Santos, C

    2017-03-01

    Soil and water contamination by lead (Pb) remains a topic of great concern, particularly regarding crop production. The admissible Pb values in irrigation water in several countries range from ≈0.1 to ≈5 mg L(-1). In order to evaluate putative effects of Pb within legal doses on crops growth, we exposed Lactuca sativa seeds and seedlings to increasing doses of Pb(NO3)2 up to 20 mg L(-1). The OECD parameter seed germination and seedling/plant growth were not affected by any of the Pb-concentrations used. However, for doses higher than 5 mg L(-1) significant DNA damage was detected: Comet assay detected DNA fragmentation at ≥ 5 mg L(-1) and presence of micronuclei (MN) were detected for 20 mg L(-1). Also, cell cycle impairment was observed for doses as low as 0.05 mg L(-1) and 0.5 mg L(-1) (mostly G2 arrest). Our data show that for the low doses of Pb used, the OECD endpoints were not able to detect toxicity, while more sensitive endpoints (related with DNA damage and mitotic/interphase disorders) identified genotoxic and cytostatic effects. Furthermore, the nature of the genotoxic effect was dependent on the concentration. Finally, we recommend that MN test and the comet assay should be included as sensitive endpoints in (eco)toxicological assays.

  2. Impact of dose and volume on radiation-induced mucositis.

    PubMed

    Mantini, Giovanna; Manfrida, Stefania; Cellini, Francesco; Giammarino, Daniela; Petrone, Adelina; Vitucci, Pasquale; Cellini, Numa

    2005-01-01

    There is a relationship between a given radiation dose and the resulting biological effect in the management of head and neck cancer. Radiation mucositis represents a frequent complication in cancer chemoradiation. Its prevention and treatment are major goals in radiation therapy schedules. Critical tissues can be spared using high conformal radiation therapy (3DCRT) based on consensus guidelines for target volume. Current approaches to radiation mucositis with respect to the dose and volume impact are illustrated. The monitoring system of late toxicity used by the authors is presented.

  3. A model to calculate the induced dose rate around an 18 MV ELEKTA linear accelerator.

    PubMed

    Perrin, Bruce; Walker, Anne; Mackay, Ranald

    2003-03-07

    The dose rate due to activity induced by (gamma, n) reactions around an ELEKTA Precise accelerator running at 18 MV is reported. A model to calculate the induced dose rate for a variety of working practices has been derived and compared to the measured values. From this model, the dose received by the staff using the machine can be estimated. From measured dose rates at the face of the linear accelerator for a 10 x 10 cm2 jaw setting at 18 MV an activation coefficient per MU was derived for each of the major activation products. The relative dose rates at points around the linac head, for different energy and jaw settings, were measured. Dose rates adjacent to the patient support system and portal imager were also measured. A model to calculate the dose rate at these points was derived, and compared to those measured over a typical working week. The model was then used to estimate the maximum dose to therapists for the current working schedule on this machine. Calculated dose rates at the linac face agreed to within +/- 12% of those measured over a week, with a typical dose rate of 4.5 microSv h(-1) 2 min after the beam has stopped. The estimated maximum annual whole body dose for a treatment therapist, with the machine treating at only 18 MV, for 60000 MUs per week was 2.5 mSv. This compares well with value of 2.9 mSv published for a Clinac 21EX. A model has been derived to calculate the dose from the four dominant activation products of an ELEKTA Precise 18 MV linear accelerator. This model is a useful tool to calculate the induced dose rate around the treatment head. The model can be used to estimate the dose to the staff for typical working patterns.

  4. Quantification of DNA strand breaks and abasic sites by oxime derivatization and accelerator mass spectrometry: application to gamma-radiation and peroxynitrite.

    PubMed

    Zhou, Xinfeng; Liberman, Rosa G; Skipper, Paul L; Margolin, Yelena; Tannenbaum, Steven R; Dedon, Peter C

    2005-08-01

    We report a highly sensitive method to quantify abasic sites and deoxyribose oxidation products arising in damaged DNA. The method exploits the reaction of aldehyde- and ketone-containing deoxyribose oxidation products and abasic sites with [(14)C]methoxyamine to form stable oxime derivatives, as originally described by Talpaert-Borle and Liuzzi [Reaction of apurinic/apyrimidinic sites with [(14)C]methoxyamine. A method for the quantitative assay of AP sites in DNA, Biochim. Biophys. Acta 740 (1983) 410-416]. The sensitivity of the method was dramatically improved by the application of accelerator mass spectrometry to quantify the (14)C, with a limit of detection of 1 lesion in 10(6) nucleotides in 1 microg of DNA. The method was validated using DNA containing a defined quantity of abasic sites, with a >0.95 correlation between the quantities of abasic sites and those of methoxyamine labels. The original applications of this and similar oxyamine derivatization methods have assumed that abasic sites are the only aldehyde-containing DNA damage products. However, deoxyribose oxidation produces strand breaks and abasic sites containing a variety of degradation products with aldehyde and ketone moieties. To assess the utility of methoxyamine labeling for quantifying strand breaks and abasic sites, the method was applied to plasmid DNA treated with gamma-radiation and peroxynitrite. For gamma-radiation, there was a 0.99 correlation between the quantity of methoxyamine labels and the quantity of strand breaks and abasic sites determined by a plasmid nicking assay; the abasic sites comprised less than 10% of the radiation-induced DNA damage. Studies with peroxynitrite demonstrate that the method, in conjunction with DNA repair enzymes that remove damaged bases to produce aldehydic sugar residues or abasic sites, is also applicable to quantifying nucleobase lesions in addition to strand break products. Compared to other abasic site quantification techniques, the modified

  5. ACDOS2: an improved neutron-induced dose rate code

    SciTech Connect

    Lagache, J.C.

    1981-06-01

    To calculate the expected dose rate from fusion reactors as a function of geometry, composition, and time after shutdown a computer code, ACDOS2, was written, which utilizes up-to-date libraries of cross-sections and radioisotope decay data. ACDOS2 is in ANSI FORTRAN IV, in order to make it readily adaptable elsewhere.

  6. Determining the radon exhalation rate from a gold mine tailings dump by measuring the gamma radiation.

    PubMed

    Ongori, Joash N; Lindsay, Robert; Newman, Richard T; Maleka, Peane P

    2015-02-01

    The mining activities taking place in Gauteng province, South Africa have caused millions of tons of rocks to be taken from underground to be milled and processed to extract gold. The uranium bearing tailings are placed in an estimated 250 dumps covering a total area of about 7000 ha. These tailings dumps contain considerable amounts of radium and have therefore been identified as large sources of radon. The size of these dumps make traditional radon exhalation measurements time consuming and it is difficult to get representative measurements for the whole dump. In this work radon exhalation measurements from the non-operational Kloof mine dump have been performed by measuring the gamma radiation from the dump fairly accurately over an area of more than 1 km(2). Radon exhalation from the mine dump have been inferred from this by laboratory-based and in-situ gamma measurements. Thirty four soil samples were collected at depths of 30 cm and 50 cm. The weighted average activity concentrations in the soil samples were 308 ± 7 Bq kg(-1), 255 ± 5 Bq kg(-1) and 18 ± 1 Bq kg(-1) for (238)U, (40)K and (232)Th, respectively. The MEDUSA (Multi-Element Detector for Underwater Sediment Activity) γ-ray detection system was used for field measurements. The radium concentrations were then used with soil parameters to obtain the radon flux using different approaches such as the IAEA (International Atomic Energy Agency) formula. Another technique the MEDUSA Laboratory Technique (MELT) was developed to map radon exhalation based on (1) recognising that radon exhalation does not affect (40)K and (232)Th activity concentrations and (2) that the ratio of the activity concentration of the field (MEDUSA) to the laboratory (HPGe) for (238)U and (40)K or (238)U and (232)Th will give a measure of the radon exhalation at a particular location in the dump. The average, normalised radon flux was found to be 0.12 ± 0.02 Bq m(-2) s(-1) for the mine dump.

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

    SciTech Connect

    Lim, Y.H.

    1986-01-01

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

  8. Beneficial effects of low dose radiation in response to the oncogenic KRAS induced cellular transformation

    PubMed Central

    Kim, Rae-Kwon; Kim, Min-Jung; Seong, Ki Moon; Kaushik, Neha; Suh, Yongjoon; Yoo, Ki-Chun; Cui, Yan-Hong; Jin, Young Woo; Nam, Seon Young; Lee, Su-Jae

    2015-01-01

    Recently low dose irradiation has gained attention in the field of radiotherapy. For lack of understanding of the molecular consequences of low dose irradiation, there is much doubt concerning its risks on human beings. In this article, we report that low dose irradiation is capable of blocking the oncogenic KRAS-induced malignant transformation. To address this hypothesis, we showed that low dose irradiation, at doses of 0.1 Gray (Gy); predominantly provide defensive response against oncogenic KRAS -induced malignant transformation in human cells through the induction of antioxidants without causing cell death and acts as a critical regulator for the attenuation of reactive oxygen species (ROS). Importantly, we elucidated that knockdown of antioxidants significantly enhanced ROS generation, invasive and migratory properties and abnormal acini formation in KRAS transformed normal as well as cancer cells. Taken together, this study demonstrates that low dose irradiation reduces the KRAS induced malignant cellular transformation through diminution of ROS. This interesting phenomenon illuminates the beneficial effects of low dose irradiation, suggesting one of contributory mechanisms for reducing the oncogene induced carcinogenesis that intensify the potential use of low dose irradiation as a standard regimen. PMID:26515758

  9. Beneficial effects of low dose radiation in response to the oncogenic KRAS induced cellular transformation.

    PubMed

    Kim, Rae-Kwon; Kim, Min-Jung; Seong, Ki Moon; Kaushik, Neha; Suh, Yongjoon; Yoo, Ki-Chun; Cui, Yan-Hong; Jin, Young Woo; Nam, Seon Young; Lee, Su-Jae

    2015-10-30

    Recently low dose irradiation has gained attention in the field of radiotherapy. For lack of understanding of the molecular consequences of low dose irradiation, there is much doubt concerning its risks on human beings. In this article, we report that low dose irradiation is capable of blocking the oncogenic KRAS-induced malignant transformation. To address this hypothesis, we showed that low dose irradiation, at doses of 0.1 Gray (Gy); predominantly provide defensive response against oncogenic KRAS -induced malignant transformation in human cells through the induction of antioxidants without causing cell death and acts as a critical regulator for the attenuation of reactive oxygen species (ROS). Importantly, we elucidated that knockdown of antioxidants significantly enhanced ROS generation, invasive and migratory properties and abnormal acini formation in KRAS transformed normal as well as cancer cells. Taken together, this study demonstrates that low dose irradiation reduces the KRAS induced malignant cellular transformation through diminution of ROS. This interesting phenomenon illuminates the beneficial effects of low dose irradiation, suggesting one of contributory mechanisms for reducing the oncogene induced carcinogenesis that intensify the potential use of low dose irradiation as a standard regimen.

  10. Pretreatment with low doses of acenocoumarol inhibits the development of acute ischemia/reperfusion-induced pancreatitis.

    PubMed

    Warzecha, Z; Sendur, P; Ceranowicz, P; Dembinski, M; Cieszkowski, J; Kusnierz-Cabala, B; Tomaszewska, R; Dembinski, A

    2015-10-01

    Coagulative disorders are known to occur in acute pancreatitis and are related to the severity of this disease. Various experimental and clinical studies have shown protective and therapeutic effect of heparin in acute pancreatitis. Aim of the present study was to determine the influence of acenocoumarol, a vitamin K antagonist, on the development of acute pancreatitis. Studies were performed on male Wistar rats weighing 250 - 270 g. Acenocoumarol at the dose of 50, 100 or 150 μg/kg/dose or vehicle were administered once a day for 7 days before induction of acute pancreatitis. Acute pancreatitis was induced in rats by pancreatic ischemia followed by reperfusion. The severity of acute pancreatitis was assessed after 5-h reperfusion. Pretreatment with acenocoumarol given at the dose of 50 or 100 μg/kg/dose reduced morphological signs of acute pancreatitis. These effects were accompanied with a decrease in the pancreatitis-evoked increase in serum activity of lipase and serum concentration of pro-inflammatory interleukin-1β. Moreover, the pancreatitis-evoked reductions in pancreatic DNA synthesis and pancreatic blood flow were partially reversed by pretreatment with acenocoumarol given at the dose of 50 and 100 μg/kg/dose. Administration of acenocoumarol at the dose of 150 μg/kg/dose did not exhibit any protective effect against ischemia/reperfusion-induced pancreatitis. We concluded that pretreatment with low doses of acenocoumarol reduces the severity of ischemia/reperfusion-induced acute pancreatitis.

  11. The radiation tolerance of MTP and LC optical fibre connectors to 500 kGy(Si) of gamma radiation

    NASA Astrophysics Data System (ADS)

    Hall, D. C.; Hamilton, P.; Huffman, B. T.; Teng, P. K.; Weidberg, A. R.

    2012-04-01

    The LHC luminosity upgrade, known as the High Luminosity LHC (HL-LHC), will require high-speed optical links to read out data from the detectors. The optical fibre connectors contained within such a link must have a small form factor and be capable of operating in the harsh radiation environment at the HL-LHC. MTP ribbon fibre connectors and LC single fibre connectors were exposed to 500 kGy(Si) of gamma radiation and their radiation hardness was investigated. Neither type of connector exhibited evidence for any significant radiation damage and both connectors could be qualified for use at HL-LHC detectors.

  12. [Effect of gamma-radiation on the activity of proteases associated with spleen and brain nuclear histones of young and old rats].

    PubMed

    Kutsyĭ, M P

    2011-01-01

    It has been found that proteases specifically splitting histones are associated with histones from spleen and brain nuclei of 4- and 26-month-old rats. The activity ofproteases isolated together with histones increases after irradiation of rats with 10 Gy The activation degree of these proteases depends on the animal age and postradiation period. Activation ofhistone-associated proteases by means of gamma-radiation is more pronounced in spleen nuclei from old rats than from the young ones. Irradiation of animals has been found to reduce histone H1 and core histone contents in the spleen and brain nuclei of both young and old rats. The radiation-induced proteolysis ofhistone H1 and core histones in spleen and brain nuclei leads to chromatin deconden-sation and DNA degradation by nucleases. The activity of histone-associated proteases is substantially higher in the nuclei of intensively proliferating spleen cells than in the brain nuclei. The experimental data indicate that histone-associated proteases participate in the regulation of DNA transcription, replication, and degradation.

  13. Characterization of binge-dosed methamphetamine-induced neurotoxicity and neuroinflammation.

    PubMed

    McConnell, Sarah E A; O'Banion, M Kerry; Cory-Slechta, Deborah A; Olschowka, John A; Opanashuk, Lisa A

    2015-09-01

    Methamphetamine (MA) is a potent, highly addictive psychostimulant abused by millions of people worldwide. MA induces neurotoxicity, damaging striatal dopaminergic terminals, and neuroinflammation, with striatal glial activation leading to pro-inflammatory cytokine and reactive oxygen species production. It is unclear whether MA-induced neuroinflammation contributes to MA-induced neurotoxicity. In the current study, we examined the linkage between the time course and dose response of MA-induced neurotoxicity and neuroinflammation. Adult male mice underwent a binge dosing regimen of four injections given every 2h with doses of 2, 4, 6, or 8 mg/kg MA per injection, and were sacrificed after 1, 3, 7, or 14 days. Binge MA treatment dose-dependently caused hyperthermia and induced hypoactivity after one day, though activity returned to control levels within one week. Striatal dopamine (DA) was diminished one day after treatment with at least 4 mg/kg MA, while DA turnover rates peaked after seven days. Although striatal tyrosine hydroxylase and DA transporter levels were also decreased one day after treatment with at least 4 mg/kg MA, they trended toward recovery by day 14. All doses of MA activated striatal glia within one day. While astrocyte activation persisted, microglial activation was attenuated over the two weeks of the study. These findings help clarify the relationship between MA-induced neuroinflammation and neurotoxicity, particularly regarding their temporal and dose-specific dynamics.

  14. Effects of Respiration-Induced Density Variations on Dose Distributions in Radiotherapy of Lung Cancer

    SciTech Connect

    Mexner, Vanessa; Wolthaus, Jochem W.H.; Herk, Marcel van; Damen, Eugene M.F.; Sonke, Jan-Jakob

    2009-07-15

    Purpose: To determine the effect of respiration-induced density variations on the estimated dose delivered to moving structures and, consequently, to evaluate the necessity of using full four-dimensional (4D) treatment plan optimization. Methods and Materials: In 10 patients with large tumor motion (median, 1.9 cm; range, 1.1-3.6 cm), the clinical treatment plan, designed using the mid-ventilation ([MidV]; i.e., the 4D-CT frame closest to the time-averaged mean position) CT scan, was recalculated on all 4D-CT frames. The cumulative dose was determined by transforming the doses in all breathing phases to the MidV geometry using deformable registration and then averaging the results. To determine the effect of density variations, this cumulative dose was compared with the accumulated dose after similarly deforming the planned (3D) MidV-dose in each respiratory phase using the same transformation (i.e., 'blurring the dose'). Results: The accumulated tumor doses, including and excluding density variations, were almost identical. Relative differences in the minimum gross tumor volume (GTV) dose were less than 2% for all patients. The relative differences were even smaller in the mean lung dose and the V20 (<0.5% and 1%, respectively). Conclusions: The effect of respiration-induced density variations on the dose accumulated over the respiratory cycle was very small, even in the presence of considerable respiratory motion. A full 4D-dose calculation for treatment planning that takes into account such density variations is therefore not required. Planning using the MidV-CT derived from 4D-CT with an appropriate margin for geometric uncertainties is an accurate and safe method to account for respiration-induced anatomy variations.

  15. [Mechanisms of gamma-inducible death of Jurkat cells line].

    PubMed

    Gamkrelidze, M M; Bezhitashvili, N D; Pavliashvili, A T; Mchedlishvili, T V; Sanikidze, T V

    2008-06-01

    Mechanisms of radio-inducible death of Jurkat cells were investigated. Human lymphoblastoid T-cell line Jurkat is widely established model for studying apoptosis mechanisms. The cell was radiated by "Teragam" (Czech Republic) by dose 2 g during 1 minute. After radiation cells were incubated at standard conditions during 24 hours. After gamma radiation in cell population amount of cells in gaplois (apoptotic G 0) stage was increased 8,2 folds, in diplois (G 0/G1) stage - by 17%, in synthetic (S) stage decreased by 35% and tetraploid (G2/M) stage by 73% in comparison to control group. It was revealed intensive production of free radicals of oxygen and nitric oxide and decreasing activity of antioxidant enzymes (superoxidismutasa, catalasa and glutathione peroxidase). Revealed dependence between intensification of apoptosis and radiation-induced arrest of cell cycle G2/M phase may be determined by excess amount of free oxygen and nitrogen radicals generated in Jurkat cells as a result of nondirect effects of low doses of gamma radiation.

  16. Gamma radiation interacts with melanin to alter its oxidation-reduction potential and results in electric current production.

    PubMed

    Turick, Charles E; Ekechukwu, Amy A; Milliken, Charles E; Casadevall, Arturo; Dadachova, Ekaterina

    2011-08-01

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

  17. Advanced performance and scalability of Si nanowire field-effect transistors analyzed using noise spectroscopy and gamma radiation techniques

    SciTech Connect

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

    2013-11-28

    High-quality Si nanowire field effect transistors (FETs) were fabricated using thermal nanoimprint and chemical wet etching technologies. FET structures of different lengths demonstrate high carrier mobility with values of about 750 cm{sup 2}/Vs and low volume densities of active traps in the dielectric layers of 5 × 10{sup 17} cm{sup −3} eV{sup −1}. We investigated the transport properties of these n-type channel structures using low-frequency noise spectroscopy before and after gamma radiation treatment. Before gamma irradiation, FET structures with lengths of less than 4 μm exhibited noise from contact regions with 1/(L{sup 2}) dependence for the relative 1/f noise. After gamma radiation, the spectra reflected the priority of channel noise with 1/L dependence for all samples. The transport characteristics show that the fabricated nanowire FETs improved scalability, decreased parameter scattering, and increased stability after treatment. The results demonstrate that these nanowire FETs are promising for nanoelectronic and biosensor applications due to the cost-efficient technology and advanced performance of FETs with improved stability and reliability.

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

    SciTech Connect

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

    2011-05-17

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

  19. 1H NMR metabolomics study of spleen from C57BL/6 mice exposed to gamma radiation

    DOE PAGES

    Xiao, Xiongjie; Hu, M.; Liu, M.; ...

    2016-01-27

    Due to the potential risk of accidental exposure to gamma radiation, it’s critical to identify the biomarkers of radiation exposed creatures. In the present study, NMR based metabolomics combined with multivariate data analysis to evaluate the metabolites changed in the C57BL/6 mouse spleen after 4 days whole body exposure to 3.0 Gy and 7.8 Gy gamma radiations. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employed for classification and identification potential biomarkers associated with gamma irradiation. Two different strategies for NMR spectral data reduction (i.e., spectral binning and spectral deconvolution) are combined with normalize tomore » constant sum and unit weight before multivariate data analysis, respectively. The combination of spectral deconvolution and normalization to unit weight is the best way for identifying discriminatory metabolites between the irradiation and control groups. Normalized to the constant sum may achieve some pseudo biomarkers. PCA and OPLS results shown that the exposed groups can be well separated from the control group. Leucine, 2-aminobutyrate, valine, lactate, arginine, glutathione, 2-oxoglutarate, creatine, tyrosine, phenylalanine, π-methylhistidine, taurine, myoinositol, glycerol and uracil are significantly elevated while ADP is decreased significantly. As a result, these significantly changed metabolites are associated with multiple metabolic pathways and may be potential biomarkers in the spleen exposed to gamma irradiation.« less

  20. 1H NMR metabolomics study of spleen from C57BL/6 mice exposed to gamma radiation

    SciTech Connect

    Xiao, Xiongjie; Hu, M.; Liu, M.; Hu, Jianzhi Z.

    2016-01-27

    Due to the potential risk of accidental exposure to gamma radiation, it’s critical to identify the biomarkers of radiation exposed creatures. In the present study, NMR based metabolomics combined with multivariate data analysis to evaluate the metabolites changed in the C57BL/6 mouse spleen after 4 days whole body exposure to 3.0 Gy and 7.8 Gy gamma radiations. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employed for classification and identification potential biomarkers associated with gamma irradiation. Two different strategies for NMR spectral data reduction (i.e., spectral binning and spectral deconvolution) are combined with normalize to constant sum and unit weight before multivariate data analysis, respectively. The combination of spectral deconvolution and normalization to unit weight is the best way for identifying discriminatory metabolites between the irradiation and control groups. Normalized to the constant sum may achieve some pseudo biomarkers. PCA and OPLS results shown that the exposed groups can be well separated from the control group. Leucine, 2-aminobutyrate, valine, lactate, arginine, glutathione, 2-oxoglutarate, creatine, tyrosine, phenylalanine, π-methylhistidine, taurine, myoinositol, glycerol and uracil are significantly elevated while ADP is decreased significantly. As a result, these significantly changed metabolites are associated with multiple metabolic pathways and may be potential biomarkers in the spleen exposed to gamma irradiation.

  1. Enrichment of magnetic alignment stimulated by {gamma}-radiation in core-shell type nanoparticle Mn-Zn ferrite

    SciTech Connect

    Naik, P. P.; Tangsali, R. B.; Sonaye, B.; Sugur, S.

    2013-02-05

    Core shell type nanoparticle Mn{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4} systems with x=0.55, 0.65 and 0.75 were prepared using autocombustion method. The systems were characterized using tools like XRD and IR for structure confirmation. Magnetic parameter measurements like Saturation magnetization and coercivity were obtained from hysteresis loop which exhibited a symmetry shift due to core shell nature of the nanoparticles. Nanoparticles of particle size between 21.2nm to 25.7nm were found to show 20 percent shrinkage after being radiated by the {gamma}-radiation. This is due to variation in the cation distribution which also affects the cell volume of the cubic cell. Lattice constant reduction observed is reflected in the magnetic properties of the samples. A considerable hike in the saturation magnetization of the samples was observed due to enrichment of magnetic alignment in the magnetic core of the particles. Samples under investigation were irradiated with gamma radiation from Co{sup 60} source for different time intervals.

  2. 1H NMR Metabolomics Study of Spleen from C57BL/6 Mice Exposed to Gamma Radiation

    PubMed Central

    Xiao, X; Hu, M; Liu, M; Hu, JZ

    2016-01-01

    Due to the potential risk of accidental exposure to gamma radiation, it’s critical to identify the biomarkers of radiation exposed creatures. In the present study, NMR based metabolomics combined with multivariate data analysis to evaluate the metabolites changed in the C57BL/6 mouse spleen after 4 days whole body exposure to 3.0 Gy and 7.8 Gy gamma radiations. Principal component analysis (PCA) and orthogonal projection to latent structures analysis (OPLS) are employed for classification and identification potential biomarkers associated with gamma irradiation. Two different strategies for NMR spectral data reduction (i.e., spectral binning and spectral deconvolution) are combined with normalize to constant sum and unit weight before multivariate data analysis, respectively. The combination of spectral deconvolution and normalization to unit weight is the best way for identifying discriminatory metabolites between the irradiation and control groups. Normalized to the constant sum may achieve some pseudo biomarkers. PCA and OPLS results shown that the exposed groups can be well separated from the control group. Leucine, 2-aminobutyrate, valine, lactate, arginine, glutathione, 2-oxoglutarate, creatine, tyrosine, phenylalanine, π-methylhistidine, taurine, myoinositol, glycerol and uracil are significantly elevated while ADP is decreased significantly. These significantly changed metabolites are associated with multiple metabolic pathways and may be potential biomarkers in the spleen exposed to gamma irradiation. PMID:27019763

  3. Low-Dose Aronia melanocarpa Concentrate Attenuates Paraquat-Induced Neurotoxicity.

    PubMed

    Case, A J; Agraz, D; Ahmad, I M; Zimmerman, M C

    2016-01-01

    Herbicides containing paraquat may contribute to the pathogenesis of neurodegenerative disorders such as Parkinson's disease. Paraquat induces reactive oxygen species-mediated apoptosis in neurons, which is a primary mechanism behind its toxicity. We sought to test the effectiveness of a commercially available polyphenol-rich Aronia melanocarpa (aronia berry) concentrate in the amelioration of paraquat-induced neurotoxicity. Considering the abundance of antioxidants in aronia berries, we hypothesized that aronia berry concentrate attenuates the paraquat-induced increase in reactive oxygen species and protects against paraquat-mediated neuronal cell death. Using a neuronal cell culture model, we observed that low doses of aronia berry concentrate protected against paraquat-mediated neurotoxicity. Additionally, low doses of the concentrate attenuated the paraquat-induced increase in superoxide, hydrogen peroxide, and oxidized glutathione levels. Interestingly, high doses of aronia berry concentrate increased neuronal superoxide levels independent of paraquat, while at the same time decreasing hydrogen peroxide. Moreover, high-dose aronia berry concentrate potentiated paraquat-induced superoxide production and neuronal cell death. In summary, aronia berry concentrate at low doses restores the homeostatic redox environment of neurons treated with paraquat, while high doses exacerbate the imbalance leading to further cell death. Our findings support that moderate levels of aronia berry concentrate may prevent reactive oxygen species-mediated neurotoxicity.

  4. Low-Dose Aronia melanocarpa Concentrate Attenuates Paraquat-Induced Neurotoxicity

    PubMed Central

    Case, A. J.; Agraz, D.; Ahmad, I. M.; Zimmerman, M. C.

    2016-01-01

    Herbicides containing paraquat may contribute to the pathogenesis of neurodegenerative disorders such as Parkinson's disease. Paraquat induces reactive oxygen species-mediated apoptosis in neurons, which is a primary mechanism behind its toxicity. We sought to test the effectiveness of a commercially available polyphenol-rich Aronia melanocarpa (aronia berry) concentrate in the amelioration of paraquat-induced neurotoxicity. Considering the abundance of antioxidants in aronia berries, we hypothesized that aronia berry concentrate attenuates the paraquat-induced increase in reactive oxygen species and protects against paraquat-mediated neuronal cell death. Using a neuronal cell culture model, we observed that low doses of aronia berry concentrate protected against paraquat-mediated neurotoxicity. Additionally, low doses of the concentrate attenuated the paraquat-induced increase in superoxide, hydrogen peroxide, and oxidized glutathione levels. Interestingly, high doses of aronia berry concentrate increased neuronal superoxide levels independent of paraquat, while at the same time decreasing hydrogen peroxide. Moreover, high-dose aronia berry concentrate potentiated paraquat-induced superoxide production and neuronal cell death. In summary, aronia berry concentrate at low doses restores the homeostatic redox environment of neurons treated with paraquat, while high doses exacerbate the imbalance leading to further cell death. Our findings support that moderate levels of aronia berry concentrate may prevent reactive oxygen species-mediated neurotoxicity. PMID:26770655

  5. Adhesion of leukocytes to dermal endothelial cells is induced after single-dose, but reduced after repeated doses of UVA.

    PubMed

    Heckmann, M; Pirthauer, M; Plewig, G

    1997-12-01

    Approximately 20-50% of ultraviolet A (UVA) irradiation delivered to the skin surface may reach the human dermal microvascular endothelial cells (HDMEC) that play a pivotal role in cellular inflammatory tissue; however, the pathophysiologic role of HDMEC in UVA-induced skin changes is largely unknown. Based on previous in vivo and in vitro studies revealing UVA-induced expression of endothelial adhesion molecules, we studied isolated HDMEC under various conditions in order to further delineate the impact of UVA on these cells. The expression of cell adhesion molecules was determined by flow cytometry and the resulting changes of stable adhesion of leukocytes to endothelial cells were quantitated for granulocytes, lymphocytes, and monocytes using a newly developed multicellular adhesion assay. Additionally, antibody blocking experiments were performed to delineate the role of individual cell adhesion molecules in UVA-induced leukocyte adherence. High-dose polychromatic UVA (25 J per cm2, maximal emission at 375 nm) induced intercellular adhesion molecule-1 and E-selectin with different kinetics but correlating the adhesion of leukocyte subsets. This effect subsided, however, in the course of 3-6 daily applied UVA doses. Moreover, pro-inflammatory cytokine challenge by tumor necrosis factor-alpha and interleukin-1-alpha resulted in significantly weaker induction of intercellular adhesion molecule-1 and E-selectin in repeatedly UVA-exposed HDMEC. Differential quantitation of peripheral blood derived granulocytes, lymphocytes, and monocytes revealed reduced adhesion particularly of lymphocytes followed by monocytes and granulocytes compared with leukocyte adhesion to nonirradiated but cytokine-stimulated HDMEC. It is concluded that UVA substantially influences endothelial cell adhesion molecules expression and thus directly interferes with leukocyte adhesion to endothelial cells. Divergent UVA-induced effects in this respect can be attributed to the mode of UV exposure

  6. The Use of Gamma Radiation for the Treatment of Cultural Heritage in the Argentine National Atomic Energy Commission: Past, Present, and Future.

    PubMed

    Calvo, Ana Maria Del Carmen; Docters, Andrea; Miranda, María Virginia; Saparrat, Mario Carlos Nazareno

    2017-02-01

    The use of gamma radiation for treating biodeteriorated cultural heritage on paper has been studied at the Comisión Nacional de Energía Atómica-CNEA (Argentina) since 2001. In order to preserve books, publications, and documents that have been attacked by insects or fungi, gamma radiation techniques have been used at CNEA. The activities include basic research as well as their applications in infected documents and papers currently used in libraries and archives. New papers were subjected to accelerated ageing in order to evaluate the effects of gamma radiation on their physical and mechanical properties. Current studies include resistance to radiation in two batches of highly cellulolytic fungi, associated with indoor environment. They are present in papers and adhesives used for conservation purposes at the Laboratory of Preventive Conservation and Restoration of Documents. A joint study has been started in CNEA with the National University of La Plata.

  7. DETECTION OF LOW DOSE RADIATION INDUCED DNA DAMAGE USING TEMPERATURE DIFFERENTIAL FLUORESCENCE ASSAY

    EPA Science Inventory

    A rapid and sensitive fluorescence assay for radiation-induced DNA damage is reported. Changes in temperature-induced strand separation in both calf thymus DNA and plasmid DNA (puc 19 plasmid from Escherichia coli) were measured after exposure to low doses of radiation. Exposur...

  8. DETECTION OF LOW DOSE RADIATION INDUCED DNA DAMAGE USING TEMPERATURE DIFFERENNTIAL FLUORESENCE ASSAY

    EPA Science Inventory

    A rapid and sensitive fluorescence assay for radiation-induced DNA damage is reported. Changes in temperature-induced strand separation in both calf thymus DNA and plasmid DNA (puc 19 plasmid from Escherichia coli) were measured after exposure to low doses of radiation. Exposures...

  9. AN EXTRACT OF PENICILLIUM CHRYSOGENUM INDUCES DOSE-DEPENDENT ALLERGIC ASTHMA RESPONSES IN MICE

    EPA Science Inventory

    Rationale: Penicillium chrysogenum, a common indoor mold, is known to have several allergens and can induce allergic responses in a mouse model of allergic penicilliosis. Our hypothesis is that soluble components of P. chrysogenum (PCE) can dose-dependently induce responses typ...

  10. Dose and dose rate effects of whole-body gamma-irradiation: II. Hematological variables and cytokines

    NASA Technical Reports Server (NTRS)

    Gridley, D. S.; Pecaut, M. J.; Miller, G. M.; Moyers, M. F.; Nelson, G. A.

    2001-01-01

    The goal of part II of this study was to evaluate the effects of gamma-radiation on circulating blood cells, functional characteristics of splenocytes, and cytokine expression after whole-body irradiation at varying total doses and at low- and high-dose-rates (LDR, HDR). Young adult C57BL/6 mice (n = 75) were irradiated with either 1 cGy/min or 80 cGy/min photons from a 60Co source to cumulative doses of 0.5, 1.5, and 3.0 Gy. The animals were euthanized at 4 days post-exposure for in vitro assays. Significant dose- (but not dose-rate-) dependent decreases were observed in erythrocyte and blood leukocyte counts, hemoglobin, hematocrit, lipopolysaccharide (LPS)-induced 3H-thymidine incorporation, and interleukin-2 (IL-2) secretion by activated spleen cells when compared to sham-irradiated controls (p < 0.05). Basal proliferation of leukocytes in the blood and spleen increased significantly with increasing dose (p < 0.05). Significant dose rate effects were observed only in thrombocyte counts. Plasma levels of transforming growth factor-beta 1 (TGF-beta 1) and splenocyte secretion of tumor necrosis factor-alpha (TNF-alpha) were not affected by either the dose or dose rate of radiation. The data demonstrate that the responses of blood and spleen were largely dependent upon the total dose of radiation employed and that an 80-fold difference in the dose rate was not a significant factor in the great majority of measurements.

  11. Redox maintenance and concerted modulation of gene expression and signaling pathways by a nanoformulation of curcumin protects peripheral blood mononuclear cells against gamma radiation.

    PubMed

    Soltani, Behrooz; Ghaemi, Nasser; Sadeghizadeh, Majid; Najafi, Farhood

    2016-09-25

    Exposure to ionizing radiation (IR) could be detrimental to health. Oxidative stress, DNA damage, and inflammation are implicated in radiation damage. Curcumin, a natural polyphenol, has remarkable antioxidant, anti-inflammation and anticarcinogenic properties and is reported to protect cells and organisms against gamma-rays. We have recently enhanced solubility of curcumin via a novel dendrosomal nanoformulation (DNC). The objective of this study was to assess the potential efficacy of this nanoformulation in protecting human peripheral blood mononuclear cells (PBMC) against gamma-radiation. IR-induced damage was evident in reactive oxygen species, antioxidant enzymes activities, glutathione, lipid peroxidation, and viability assays. Treatment by DNC, showing superiority to curcumin, effectively counteracted these effects and reduced DNA damage as determined via 8-OHdG levels and lipid peroxidation as measured by the level of TBARS (as well as lipid hydroperoxides and 8-isoprostane). PBMC pretreatment by DNC prior to irradiation proved effective as well. Uptake kinetics revealed enhanced uptake of DNC compared to curcumin, particularly after irradiation. DNC suppressed IR-induced NF-κB activation 18 h post-irradiation. It induced Nrf2 binding activity early after irradiation which was sustained to 18 h. Gene expression analysis of a chosen set of radiation response genes in irradiated PBMC revealed a similar profile for DNA damage response and repair genes including FDXR, XPC, DDB2, and GADD45 in DNC-treated cells compared to IR control. However, in response to radiation, an altered profile of expression was noticed for CDKN1A (p21), MDM2, IFNG, and BBC3 (PUMA) genes after DNC treatment.

  12. Local Correlation Between Monte-Carlo Dose and Radiation-Induced Fibrosis in Lung Cancer Patients

    SciTech Connect

    Stroian, Gabriela; Martens, Chandra; Souhami, Luis; Collins, D. Louis; Seuntjens, Jan

    2008-03-01

    Purpose: To present a new method of evaluating the correlation between radiotherapy (RT)-induced fibrosis and the local dose delivered to non-small-cell lung cancer patients. Methods and Materials: Treatment plans were generated using the CadPlan treatment planning system (pencil beam, no heterogeneity corrections), and RT delivery was based on these plans. Retrospective Monte-Carlo dose calculations were performed, and the Monte-Carlo distributions of dose to real tissue were calculated using the planning computed tomography (CT) images and the number of monitor units actually delivered. After registration of the follow-up CT images with the planning CT images, different grades of radiologic fibrosis were automatically segmented on the follow-up CT images. Subsequently, patient-specific fibrosis probabilities were studied as a function of the local dose and a function of time after RT completion. Results: A strong patient-specific variation in the fibrosis volumes was found during the follow-up period. For both lungs, the threshold dose for which the probability of fibrosis became significant coincided with the threshold dose at which significant volumes of the lung were exposed. At later stages, only fibrosis localized in the high-dose regions persisted for both lungs. Overall, the Monte-Carlo dose distributions correlated much better with the probability of RT-induced fibrosis than did the CadPlan dose distributions. Conclusion: The presented method allows for an accurate, systematic, patient-specific and post-RT time-dependent numeric study of the relationship between RT-induced fibrosis and the local dose.

  13. The Dosimetric Parameters Investigation of the Pulsed X-ray and Gamma Radiation Sources

    NASA Astrophysics Data System (ADS)

    Stuchebrov, S. G.; Miloichikova, I. A.; Shilova, X. O.

    2016-01-01

    The most common type of radiation used for diagnostic purposes are X-rays. However, X-rays methods have limitations related to the radiation dose for the biological objects. It is known that the use of the pulsed emitting source synchronized with the detection equipment for internal density visualization of objects significant reduces the radiation dose to the object. In the article the analysis of the suitability of the different dosimetric equipment for the radiation dose estimation of the pulsed emitting sources is carried out. The approbation results on the pulsed X-ray generator RAP-160-5 of the dosimetry systems workability with the pulse radiation and its operation range are presented. The results of the dose field investigation of the portable betatron OB-4 are demonstrated. The depth dose distribution in the air, lead and water of the pulsed bremsstrahlung generated by betatron are shown.

  14. Time and dose-response effects of honokiol on UVB-induced skin cancer development.

    PubMed

    Guillermo, Ruth F; Chilampalli, Chandeshwari; Zhang, Xiaoying; Zeman, David; Fahmy, Hesham; Dwivedi, Chandradhar

    2012-06-01

    Honokiol has shown chemopreventive effects in chemically-induced and UVB-induced skin cancer in mice. In this investigation, we assessed the time-effects of a topical low dose of honokiol (30 μg), and then the effects of different honokiol doses (30, 45, and 60 μg) on a UVB-induced skin cancer model to find an optimal dose and time for desirable chemopreventive effects. UVB radiation (30 mJ/cm(2), 5 days/week for 25 or 27 weeks) was used to induce skin carcinogenesis in SKH-1 mice. For the time-response experiment 30 μg honokiol in acetone was applied topically to the animals before the UVB exposure (30 min, 1 h, and 2 h) and after the UVB exposure (immediately, 30 min, and 1 h). Control groups were treated with acetone. For the dose-response study, animals were treated topically with acetone or honokiol (30, 45, and 60 μg) one hour before the UVB exposure. In the time-response experiment, honokiol inhibited skin tumor multiplicity by 49-58% while reducing tumor volumes by 70-89%. In the dose-response study, honokiol (30, 45, and 60 μg) significantly decreased skin tumor multiplicity by 36-78% in a dose-dependent manner, while tumor area was reduced by 76-94%. Honokiol (60 μg) significantly reduced tumor incidence by 40% as compared to control group. Honokiol applied in very low doses (30 μg) either before or after UVB radiation shows chemopreventive effects. Honokiol (30, 45, and 60 μg) prevents UVB-induced skin cancer in a dose-dependent manner. Honokiol can be an effective chemopreventive agent against skin cancer.

  15. DNA alterations and effects on growth and reproduction in Daphnia magna during chronic exposure to gamma radiation over three successive generations.

    PubMed

    Parisot, Florian; Bourdineaud, Jean-Paul; Plaire, Delphine; Adam-Guillermin, Christelle; Alonzo, Frédéric

    2015-06-01

    This study examined chronic effects of external Cs-137 gamma radiation on Daphnia magna exposed over three successive generations (F0, F1 and F2) to environmentally relevant dose rates (ranging from 0.007 to 35.4 mGy h(-1)). Investigated endpoints included survival, growth, reproduction and DNA alterations quantified using random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Results demonstrated that radiation effects on survival, growth and reproduction increased in severity from generation F0 to generation F2. Mortality after 21 days at 35.4 mGy h(-1) increased from 20% in F0 to 30% in F2. Growth was affected by a slight reduction in maximum length at 35.4 mGy h(-1) in F0 and by reductions of 5 and 13% in growth rate, respectively, at 4.70 and 35.4 mGy h(-1) in F2. Reproduction was affected by a reduction of 19% in 21 day-fecundity at 35.4 mGy h(-1) in F0 and by a delay of 1.9 days in brood release as low as 0.070 mGy h(-1) in F2. In parallel, DNA alterations became significant at decreasing dose rates over the course of F0 (from 4.70 mGy h(-1) at hatching to 0.007 mGy h(-1) after ∼21 days) and from F0 to F2 (0.070 mGy h(-1) at hatching to 0.007 mGy h(-1) after ∼21 days), demonstrating their rapid accumulation in F0 daphnids and their transmission to offspring generations. Transiently more efficient DNA repair leading to some recovery at the organism level was suggested in F1, with no effect on survival, a slight reduction of 12% in 21 day-fecundity at 35.4 mGy h(-1) and DNA alterations significant at highest dose rates only. The study improved our understanding of long term responses to low doses of radiation at the molecular and organismic levels in a non-human species for a better radioprotection of aquatic ecosystems.

  16. Establishing the irradiation dose for paper decontamination

    NASA Astrophysics Data System (ADS)

    Moise, Ioan Valentin; Virgolici, Marian; Negut, Constantin Daniel; Manea, Mihaela; Alexandru, Mioara; Trandafir, Laura; Zorila, Florina Lucica; Talasman, Catalina Mihaela; Manea, Daniela; Nisipeanu, Steluta; Haiducu, Maria; Balan, Zamfir

    2012-08-01

    Museums, libraries and archives are preserving documents that are slowly degrading due to the inherent ageing of the cellulose substrate or to the technological errors of the past (acid paper, iron gall ink). Beside this, large quantities of paper are rapidly damaged by biological attacks following natural disasters and improper storage conditions. The treatment of paper documents with ionizing radiation can be used for mass decontamination of cultural heritage items but conservators and restaurators are still reserved because of the radiation induced degradation. We conducted a study for establishing the dose needed for the effective treatment of paper documents, taking into account the biological burden and the irradiation effects on paper structure. We used physical testing specific to paper industry and less destructive analytical methods (thermal analysis). Our results show that an effective treatment can be performed with doses lower than 10 kGy. Old paper appears to be less affected by gamma radiation than recent paper but the sampling is highly affected by the non-uniform degree of the initial degradation status. The extent of testing for degradation and the magnitude of acceptable degradation should take into account the biological threat and the expected life time of the paper documents.

  17. Differential Response and Priming Dose Effect on the Proteome of Human Fibroblast and Stem Cells Induced by Exposure to Low Doses of Ionizing Radiation.

    PubMed

    Hauptmann, Monika; Haghdoost, Siamak; Gomolka, Maria; Sarioglu, Hakan; Ueffing, Marius; Dietz, Anne; Kulka, Ulrike; Unger, Kristian; Babini, Gabriele; Harms-Ringdahl, Mats; Ottolenghi, Andrea; Hornhardt, Sabine

    2016-03-01

    It has been suggested that a mechanistic understanding of the cellular responses to low dose and dose rate may be valuable in reducing some of the uncertainties involved in current risk estimates for cancer- and non-cancer-related radiation effects that are inherited in the linear no-threshold hypothesis. In this study, the effects of low-dose radiation on the proteome in both human fibroblasts and stem cells were investigated. Particular emphasis was placed on examining: 1. the dose-response relationships for the differential expression of proteins in the low-dose range (40-140 mGy) of low-linear energy transfer (LET) radiation; and 2. the effect on differential expression of proteins of a priming dose given prior to a challenge dose (adaptive response effects). These studies were performed on cultured human fibroblasts (VH10) and human adipose-derived stem cells (ADSC). The results from the VH10 cell experiments demonstrated that low-doses of low-LET radiation induced unique patterns of differentially expressed proteins for each dose investigated. In addition, a low priming radiation dose significantly changed the protein expression induced by the subsequent challenge exposure. In the ADSC the number of differentially expressed proteins was markedly less compared to VH10 cells, indicating that ADSC differ in their intrinsic response to low doses of radiation. The proteomic results are further discussed in terms of possible pathways influenced by low-dose irradiation.

  18. Gene expression profiling in undifferentiated thyroid carcinoma induced by high-dose radiation

    PubMed Central

    Bang, Hyun Soon; Choi, Moo Hyun; Kim, Cha Soon; Choi, Seung Jin

    2016-01-01

    Published gene expression studies for radiation-induced thyroid carcinogenesis have used various methodologies. In this study, we identified differential gene expression in a human thyroid epithelial cell line after exposure to high-dose γ-radiation. HTori-3 cells were exposed to 5 or 10 Gy of ionizing radiation using two dose rates (high-dose rate: 4.68 Gy/min, and low-dose rate: 40 mGy/h) and then implanted into the backs of BALB/c nude mice after 4 (10 Gy) or 5 weeks (5 Gy). Decreases in cell viability, increases in giant cell frequency, anchorage-independent growth in vitro, and tumorigenicity in vivo were observed. Particularly, the cells irradiated with 5 Gy at the high-dose rate or 10 Gy at the low-dose rate demonstrated more prominent tumorigenicity. Gene expression profiling was analyzed via microarray. Numerous genes that were significantly altered by a fold-change of >50% following irradiation were identified in each group. Gene expression analysis identified six commonly misregulated genes, including CRYAB, IL-18, ZNF845, CYP24A1, OR4N4 and VN1R4, at all doses. These genes involve apoptosis, the immune response, regulation of transcription, and receptor signaling pathways. Overall, the altered genes in high-dose rate (HDR) 5 Gy and low-dose rate (LDR) 10 Gy were more than those of LDR 5 Gy and HDR 10 Gy. Thus, we investigated genes associated with aggressive tumor development using the two dosage treatments. In this study, the identified gene expression profiles reflect the molecular response following high doses of external radiation exposure and may provide helpful information about radiation-induced thyroid tumors in the high-dose range. PMID:27006382

  19. Gis predictive mapping of terrestrial gamma radiation in the Northern State, Sudan.

    PubMed

    Hamed Bashier, E; Salih, I; Khatir Sam, A

    2012-09-01

    This study presents the evaluation of absorbed dose in air due to gamma-emitting nuclides from (238)U and (232)Th series, (40)K and (137)Cs and the corresponding geographical information system (GIS) predictive mapping for the Northern State. Activity concentration of (238)U, (232)Th , (40)K and (137)Cs in soil samples collected from different locations have been measured using high-resolution gamma spectrometry. On  average, activity concentrations were 19±4 ((238)U), 47±11 ((232)Th), 317±65 ((40)K) and 2.26 Bq kg(-1) for (137)Cs. Absorbed dose rate in air at a height of 1 m above ground surface was calculated using seven sets of dose rate conversion factors (DRCFs) and the corresponding annual effective dose was estimated. On average, the values obtained fall within a narrow range of 44 and 53 nGy h(-1), indicating that the variation in absorbed dose rate is insignificant for different DRCFs. The corresponding annual effective dose ranged from 53 to 65 µSv y(-1). Using GIS, prediction maps for concentrations of (238)U, (232)Th, (40)K and (137)Cs were produced. Also, a map for absorbed dose rate in air at a height of 1 m above the ground level was produced, which showed a trend of increasing from the west towards south-east of the State.

  20. Harnessing a radiation inducible promoter of Deinococcus radiodurans for enhanced precipitation of uranium.

    PubMed

    Misra, Chitra Seetharam; Mukhopadhyaya, Rita; Apte, Shree Kumar

    2014-11-10

    Bioremediation is an attractive option for the treatment of radioactive waste. We provide a proof of principle for augmentation of uranium bioprecipitation using the radiation inducible promoter, Pssb from Deinococcus radiodurans. Recombinant cells of D. radiodurans carrying acid phosphatase gene, phoN under the regulation of Pssb when exposed to 7 kGy gamma radiation at two different dose rates of 56.8 Gy/min and 4 Gy/min, showed 8-9 fold increase in acid phosphatase activity. Highest whole cell PhoN activity was obtained after 2h in post irradiation recovery following 8 kGy of high dose rate radiation. Such cells showed faster removal of high concentrations of uranium than recombinant cells expressing PhoN under a radiation non-inducible deinococcal promoter, PgroESL and could precipitate uranium even after continuous exposure to 0.6 Gy/min gamma radiation for 10 days. Radiation induced recombinant D. radiodurans cells when lyophilized retained high levels of PhoN activity and precipitated uranium efficiently. These results highlight the importance of using a suitable promoter for removal of radionuclides from solution.