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Sample records for apres irradiation gamma

  1. Régulation de la production, par des cellules endothéliales, de cytokines pro-inflammatoires après irradiation

    NASA Astrophysics Data System (ADS)

    van der Meeren, A.; Lafont, H.; Mathé, D.

    1998-04-01

    Gamma irradiation leads to an increased production of interleukin- (IL)-6 and IL-8 by human endothelial cells. In order to regulate the radio-induced production of these pro-inflammatory cytokines, we used the immunoregulatory cytokines IL-4 and IL-10. These agents were added either before or after a 10 Gy-irradiation. Our results show that it is possible to decrease the radio-induced production of IL-6 and IL-8 with the use of IL-4 and IL-10. Differences in the intensity of the response have been observed according to the time of treatment. The anti-inflammatory potential of both IL-4 and IL-10 was more pronounced when added after irradiation. Après irradiation gamma, des cellules endothéliales humaines ont une production accrue des interleukines (IL-) -6 et -8. Dans le but de réguler la production de ces cytokines pro-inflammatoires, nous avons utilisé des cytokines dites anti-inflammatoires, l'IL-4 et l'IL-10. Ces agents ont été ajoutés soit avant soit après une irradiation de 10Gy. Nos résultats montrent qu'il est possible de diminuer les productions radio-induites d'IL-6 et d'IL-8 par l'IL-4 et l'IL-10. Des différences dans l'intensité de la réponse ont toutefois été observées selon que l'IL-4 ou l'IL-10 ont été ajoutées avant ou après irradiation; leur efficacité anti-inflammatoire étant plus marquée lorsque les cytokines sont ajoutées après l'irradiation.

  2. Glucose stabilizes collagen sterilized with gamma irradiation.

    PubMed

    Ohan, Mark P; Dunn, Michael G

    2003-12-15

    Gamma irradiation sterilization (gamma-irradiation) fragments and denatures collagen, drastically decreasing critical physical properties. Our goal was to maintain strength and stability of gamma-irradiated collagen by adding glucose, which in theory can initiate crosslink formation in collagen during exposure to gamma-irradiation. Collagen films prepared with and without glucose were gamma-irradiated with a standard dose of 2.5 Mrad. Relative amounts of crosslinking and denaturation were approximated based on solubility and the mechanical properties of the films after hydration, heat denaturation, or incubation in enzymes (collagenase and trypsin). After exposure to gamma-irradiation, collagen films containing glucose had significantly higher mechanical properties, greater resistance to enzymatic degradation, and decreased solubility compared with control films. The entire experiment was repeated with a second set of films that were exposed first to ultraviolet irradiation (254 nm) to provide higher initial strength and then gamma-irradiated. Again, films containing glucose had significantly greater mechanical properties and resistance to enzymatic degradation compared with controls. Gel electrophoresis showed that glucose did not prevent peptide fragmentation; therefore, the higher strength and stability in glucose-incorporated films may be due to glucose-derived crosslinks. The results of this study suggest that glucose may be a useful additive to stabilize collagenous materials or tissues sterilized by gamma-irradiation.

  3. Production of modified starches by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Kang, Il-Jun; Byun, Myung-Woo; Yook, Hong-Sun; Bae, Chun-Ho; Lee, Hyun-Soo; Kwon, Joong-Ho; Chung, Cha-Kwon

    1999-04-01

    As a new processing method for the production of modified starch, gamma irradiation and four kinds of inorganic peroxides were applied to commercial corn starch. The addition of inorganic peroxides without gamma irradiation or gamma irradiation without the addition of inorganic peroxides effectively decreased initial viscosity, but did not sufficiently keep viscosity stable. The combination of adding ammonium persulfate (APS) and gamma irradiation showed the lowest initial viscosity and the best stability out of the tested four kinds of inorganic peroxides. Among the tested mixing methods of APS, soaking was found to be more effective than dry blending or spraying. Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability became feasible by the control of gamma irradiation dose levels and the amount of added APS to starch.

  4. Hardness Evolution of Gamma-Irradiated Polyoxymethylene

    NASA Astrophysics Data System (ADS)

    Hung, Chuan-Hao; Harmon, Julie P.; Lee, Sanboh

    2016-04-01

    This study focuses on analyzing hardness evolution in gamma-irradiated polyoxymethylene (POM) exposed to elevated temperatures after irradiation. Hardness increases with increasing annealing temperature and time, but decreases with increasing gamma ray dose. Hardness changes are attributed to defects generated in the microstructure and molecular structure. Gamma irradiation causes a decrease in the glass transition temperature, melting point, and extent of crystallinity. The kinetics of defects resulting in hardness changes follow a first-order structure relaxation. The rate constant adheres to an Arrhenius equation, and the corresponding activation energy decreases with increasing dose due to chain scission during gamma irradiation. The structure relaxation of POM has a lower energy barrier in crystalline regions than in amorphous ones. The hardness evolution in POM is an endothermic process due to the semi-crystalline nature of this polymer.

  5. Modifications de l'expression des gènes GST-μ et p53 dans des lignées tumorales cellulaires humaines O.R.L. après irradiation gamma : induction, études cellulaires et moléculaires

    NASA Astrophysics Data System (ADS)

    Dubessy, C.; Merlin, J. L.; Marchal, C.

    1998-04-01

    Cell sub-populations surviving to high radiation doses were selected. The KBm survival part was obtained by exposure to a mutagenic agent and irradiation, FaDum results of a progressive irradiation of FaDu. A semi-quantitative RT-PCR analysis revealed a significant overexpression of GST-μ and p53 genes for KBm and FaDum cell lines that remained stable for 18 months. The SF2, α, β, and MID parameters, determined by clonogenic assays, show no modifications of radiosensitivity. The variations of expression observed are not correlated to a radiosensitivity variation. The overexpression of GST-μ and p53 does not seem to be a radiosensitivity marker. Nous avons isolé des sous-populations de 2 lignées cellulaires humaines (KB et FaDu) de carcinomes des voies aéro-digestives supérieures survivant à de fortes doses d'irradiation. La fraction survivante KBm a été obtenu après exposition à un agent mutagène et à une irradiation, FaDum résulte de l'irradiation progressive de FaDu. Une analyse par RT-PCR semi-quantitative nous a permis de mettre en évidence une surexpression significative des gènes GST-μ et p53 pour les souches KBm et FaDum analysées après 18 mois de culture. Les paramètres, α, β, SF2, MID, déterminés par essais clonogéniques, n'indiquent pas de modification de la radiosensibilité. Les variations d'expression observées ne sont donc pas corrélées à une variation de radiosensibilité. La surexpression des gènes GST-μ et p53 ne semble pas constituer un marqueur de radiosensibilité.

  6. Dielectric relaxation of gamma irradiated muscovite mica

    SciTech Connect

    Kaur, Navjeet; Singh, Mohan; Singh, Lakhwant; Awasthi, A.M.; Lochab, S.P.

    2015-03-15

    Highlights: • The present article reports the effect of gamma irradiation on the dielectric relaxation characteristics of muscovite mica. • Dielectric and electrical relaxations have been analyzed in the framework of dielectric permittivity, electric modulus and Cole–Cole formalisms. • The frequency dependent electrical conductivity has been rationalized using Johnsher’s universal power law. • The experimentally measured electric modulus and conductivity data have been fitted using Havriliak–Negami dielectric relaxation function. - Abstract: In the present research, the dielectric relaxation of gamma irradiated muscovite mica was studied in the frequency range of 0.1 Hz–10 MHz and temperature range of 653–853 K, using the dielectric permittivity, electric modulus and conductivity formalisms. The dielectric constants (ϵ′ and ϵ′′) are found to be high for gamma irradiated muscovite mica as compared to the pristine sample. The frequency dependence of the imaginary part of complex electric modulus (M′′) and dc conductivity data conforms Arrhenius law with single value of activation energy for pristine sample and two values of activation energy for gamma irradiated mica sample. The experimentally assessed electric modulus and conductivity information have been interpreted by the Havriliak–Negami dielectric relaxation explanation. Using the Cole–Cole framework, an analysis of real and imaginary characters of the electric modulus for pristine and gamma irradiated sample was executed which reflects the non-Debye relaxation mechanism.

  7. Gamma irradiation effects in W films

    SciTech Connect

    Claro, Luiz H.; Santos, Ingrid A.; Silva, Cassia F.

    2013-05-06

    Using the van Der Pauw methodology, the surface resistivity of irradiated tungsten films deposited on Silicon substrate was measured. The films were exposed to {gamma} radiation using a isotopic {sup 60}Co source in three irradiation stages attaining 40.35 kGy in total dose. The obtained results for superficial resistivity display a time annealing features and their values are proportional to the total dose.

  8. Investigations on fiberoptic behaviour during gamma irradiation

    NASA Astrophysics Data System (ADS)

    Siehs, J.

    1980-12-01

    The behavior of bulk glasses and fiber optics under gamma irradiation and two types of annealing processes (thermal and optical) were investigated. The samples were irradiated in the thermal column of the TRIGA Mark II reactor. The irradiation induced losses of transmission were measured in a dual beam spectrophotometer. The transmission was measured one hour after reactor shut-down. Thermal annealing was done at 300, 400 and 500 C. Photo bleaching was investigated with a quartz-lamp, an arc-lamp and an UV-laser light.

  9. Mobile gamma-irradiation robot

    NASA Astrophysics Data System (ADS)

    Teply, J.; Franek, C.; Vocilka, J.; Stetka, R.; Vins, J.; Krotil, J.; Garba, A.

    1993-07-01

    The source container with 98 TBq of 137Cs and shielding made from depleted uranium has the total weight of 264 kg, height of 0.370 and diameter 0.272 m. The container is joined to accessories allowing movment of the radiation beam. The dose rate at a distance of 0.4 m in the beam axis is 50 Gy/h. Various technical means are available for manipulation and transport. The irradiation process proceeds according to a precalculated program. The safety measures have been taken to secure the possible application in historical buildings and similar objects. The licence from health physics authorities has been obtained. The first irradiation process performed is described.

  10. ESR identification of gamma-irradiated albendazole

    NASA Astrophysics Data System (ADS)

    Çolak, Seyda

    2010-01-01

    The use of ionizing radiation for sterilization of pharmaceuticals is a well-established technology. In the present work, the spectroscopic and kinetic features of the radicals induced in gamma-irradiated solid albendazole samples is investigated at different temperatures in the dose range of 3-34 kGy by electron spin resonance (ESR) spectroscopy. Irradiation with gamma radiation produced two different radical species in albendazole. They were fairly stable at room temperature but relatively unstable above room temperature, giving rise to an unresolved ESR spectrum consisting of three resonance peaks centered at g=2.0057. Decay activation energies of the contributing radical species were calculated to be 47.8 (±13.5) and 50.5 (±9.7) kJ/mol using the signal intensity decay data derived from annealing studies performed at high temperatures. A linear function of the applied dose was found to best describe the experimental dose-response data. Albendazole does not present the characteristics of good dosimetric materials. However, the discrimination of irradiated albendazole from its unirradiated form was possible even 6 months after storage in normal conditions. Based on these findings, it is concluded that albendazole and albendazole-containing drugs can be safely sterilized by gamma radiation and that ESR spectroscopy could be successfully used as a potential technique for monitoring their radiosterilization.

  11. Conformational changes of myosin by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Ju.-Woon; Yook, Hong.-Sun; Lee, Kyong.-Haeng; Kim, Jae.-Hun; Kim, Woo.-Jung; Byun, Myung.-Woo

    2000-05-01

    Conformational and decompositional changes of bovine skeletal muscle myosin caused by gamma irradiation were studied for understanding the effects of irradiation treatment on myofibrillar proteins. Myosin solution and beef cuts were irradiated 0, 1, 3, 5 and 10 kGy. Competitive indirect enzyme linked immunosorbent assay (Ci-ELISA) showed that subunits of myosin were structurally modified with different patterns. Binding abilities of anti-myosin whole molecule and anti heavy meromyosin S-1 IgG, which were produced from rabbits, with irradiated myosin decreased in the same tendency depending upon the dose. Anti-light meromyosin IgG appeared to have the highest binding ability at 3 kGy. Irradiated beef cuts (≥5 kGy) could be identified by Ci-ELISA. Myosin solution became increasingly turbid with increasing dose. Hydrophobicity of myosin solution also increased by irradiation. Electrophoretic patterns showed that the myosin heavy chain disappeared and new bands were generated at higher molecular weight ranges.

  12. Effects of gamma irradiation on deteriorated paper

    NASA Astrophysics Data System (ADS)

    Bicchieri, Marina; Monti, Michela; Piantanida, Giovanna; Sodo, Armida

    2016-08-01

    Even though gamma radiation application, also at the minimum dosage required for disinfection, causes depolymerization and degradation of the paper substrate, recently published papers seemed, instead, to suggest that γ-rays application could be envisaged in some conditions for Cultural Heritage original documents and books. In some of the published papers, the possible application of γ-rays was evaluated mainly by using mechanical tests that scarcely reflect the chemical modifications induced in the cellulosic support. In the present article the effect of low dosage γ-irradiation on cellulosic substrates was studied and monitored applying different techniques: colorimetry, spectroscopic measurements, carbonyl content and average viscometric degree of polymerization. Two different papers were investigated, a non-sized, non-filled cotton paper, and a commercial permanent paper. To simulate a real deteriorated document, which could need γ-rays irradiation, some samples were submitted to a hydrolysis treatment. We developed a treatment based on the exposition of paper to hydrochloric acid vapors, avoiding any contact of the samples with water. This method induces a degradation similar to that observed on original documents. The samples were then irradiated with 3 kGy γ-rays at a 5258 Gy/h rate. The aforementioned analyses were performed on the samples just irradiated and after artificial ageing. All tests showed negative effects of gamma irradiation on paper. Non-irradiated paper preserves better its appearance and chemical properties both in the short term and after ageing, while the irradiated samples show appreciable color change and higher oxidation extent. Since the Istituto centrale restauro e conservazione patrimonio archivistico e librario is responsible for the choice of all restoration treatments that could be applied on library and archival materials under the protection of the Italian State (http://www.icpal.beniculturali.it/allegati/DM-7

  13. Influence of gamma ray irradiation on metakaolin based sodium geopolymer

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  14. Silicon/HfO2 interface: Effects of gamma irradiation

    NASA Astrophysics Data System (ADS)

    Maurya, Savita

    2016-05-01

    Quality of MOS devices is a strong function of substrate and oxide interface. In this work we have studied how gamma photon irradiation affects the interface of a 13 nm thick, atomic layer deposited hafnium dioxide deposited on silicon wafer. CV and GV measurements have been done for pristine and irradiated samples to quantify the effect of gamma photon irradiation. Gamma photon irradiation not only introduces positive charge in the oxide and at the interface of Si/HfO2 interface but also induce phase change of oxide layer. Maximum oxide capacitances are affected by gamma photon irradiation.

  15. COBALT-60 Gamma Irradiation of Shrimp.

    NASA Astrophysics Data System (ADS)

    Sullivan, Nancy L. B.

    Meta- and ortho-tyrosine were measured using high performance liquid chromatography (HPLC) in conjunction with electrochemical detection in shrimp irradiated using cobalt-60 gamma radiation in the absorbed dose range 0.8 to 6.0 kGy, in nonirradiated shrimp, and in bovine serum albumin (BSA) irradiated in dilute aqueous solution at 25.0 kGy. Ortho-tyrosine was measured in nonirradiated BSA. Para-, meta-, and ortho-tyrosine were measured using HPLC in conjunction with uv-absorption detection in dilute aqueous solutions of phenylalanine irradiated in the absorbed dose range 16.0 to 195.0 kGy. The measured yields of tyrosine isomers were approximately linear as a function of absorbed dose in shrimp, and in irradiated solutions of phenylalanine up to 37.0 kGy. The occurrence of meta- and ortho-tyrosine, which had formerly been considered unique radiolytic products, has not previously been reported in nonirradiated shrimp or BSA. The conventional hydrolyzation and analytical techniques used in the present study to measure meta- and ortho-tyrosine may provide the basis for a method to detect and determine the dose used in food irradiation.

  16. Cobalt-60 gamma irradiation of shrimp

    SciTech Connect

    Sullivan, N.L.B.

    1993-01-01

    Meta- and ortho-tyrosine were measured using high performance liquid chromatography (HPLC) in conjunction with electrochemical detection in shrimp irradiated using cobalt-60 gamma radiation in the absorbed dose range 0.8 to 6.0 kGy, in nonirradiated shrimp, and in bovine serum albumin (BSA) irradiated in dilute aqueous solution at 25.0 kGy. Ortho-tyrosine was measured in nonirradiated BSA. Para-, meta-, and ortho-tyrosine was measured using HPLC in conjunction with uv-absorption detection in dilute aqueous solutions of phenylalanine irradiated in the absorbed dose range 16.0 to 195.0 kGy. The measured yields of tyrosine isomers were approximately linear as a function of absorbed dose in shrimp, and in irradiated solutions of phenylalanine up to 37.0 kGy. The occurrence of meta- and ortho-tyrosine, which had formerly been considered unique radiolytic products, has not previously been reported in nonirradiated shrimp or BSA. The conventional hydrolyzation and analytical techniques used in the present study to measure meta- and ortho-tyrosine may provide the basis for a method to detect and determine the dose used in food irradiation.

  17. ESR response of gamma-irradiated sulfamethazine

    NASA Astrophysics Data System (ADS)

    Çolak, Seyda; Korkmaz, Mustafa

    In the present work, characteristic features of the radiolytical intermediates produced in gamma-irradiated solid sulfamethazine (SMH) were investigated by electron spin resonance (ESR) spectroscopy. The heights of the resonance peaks, measured with respect to the spectrum baseline, were used to monitor microwave saturation, temperature and time-dependent kinetic features of the radical species contributing to the formation of recorded experimental ESR spectra. Three species having different spectroscopic and kinetic features were observed to be produced in gamma-irradiated SMH. SO2, which is the most sensitive group of radiation in the SMH molecule, was found to be at the origin of radiation-produced ionic radical species. Based on the experimental results derived from the present study, the applicability of ESR spectroscopy to radiosterilization of SMH was discussed. In the dose range of interest (0.5-10 kGy), the radiation yield of solid SMH was calculated to be very low (G=0.45) compared with those obtained for sulfonamide aqueous solutions (G=3.5-5.1). Based on these findings, it was concluded that SMH and SMH-containing drugs could be safely sterilized by gamma radiation and that ESR spectroscopy could be successfully used as a potential technique for monitoring their radiosterilization.

  18. ESR study of gamma irradiated Nylon3

    NASA Astrophysics Data System (ADS)

    Çatiker, Efkan; Güven, Olgun; Özarslan, Özdemir; Chipara, Mircea

    2013-03-01

    Nylon3 (poly-β-alanine) gamma irradiated in nitrogen was investigated by Electron Spin Resonance Spectroscopy to elucidate the type of radicals generated, their relative abundance, conversion into other radicalic species and their room temperature stability. Two types of radiation induced primary radicals have been detected. One of them (R1) occurs by hydrogen abstraction from methylene group next to the carbonyl group, while the other (R2) by hydrogen abstraction from methylene group next to amide group. R1 is observed to be converted into an alkoxy radical (R3). Decay kinetics of the radicals in nitrogen was also examined and decay mechanisms have been proposed for each radical.

  19. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

    SciTech Connect

    Clark, E.

    2011-09-22

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

  20. Effect of gamma irradiation on Korean traditional multicolored paintwork

    NASA Astrophysics Data System (ADS)

    Yoon, Minchul; Kim, Dae-Woon; Choi, Jong-il; Chung, Yong-Jae; Kang, Dai-Ill; Hoon Kim, Gwang; Son, Kwang-Tae; Park, Hae-Jun; Lee, Ju-Woon

    2015-10-01

    Gamma irradiation can destroy fungi and insects involved in the bio-deterioration of organic cultural heritages. However, this irradiation procedure can alter optical and structural properties of historical pigments used in wooden cultural heritage paintings. The crystal structure and color centers of these paintings must be maintained after application of the irradiation procedure. In this study, we investigated the effects of gamma irradiation on Korean traditional multicolored paintwork (Dancheong) for the preservation of wooden cultural heritages. The main pigments in Korean traditional wooden cultural heritages, Sukganju (Hematite; Fe2O3), Jangdan (Minium; Pb3O4), Whangyun (Crocoite; PbCrO4), and Jidang (Rutile; TiO2), were irradiated by gamma radiation at doses of 1, 5, and 20 kGy. After irradiation, changes in Commision Internationale d'Eclairage (CIE) color values (L*, a*, b*) were measured using the color difference meter, and their structural changes were analyzed using X-ray diffraction (XRD) analysis. The slightly change in less than 1 dE* unit by gamma irradiation was observed, and structural changes in the Dancheong were stable after exposure to 20 kGy gamma irradiation. In addition, gamma irradiation could be applied to painted wooden cultural properties from the Korean Temple. Based on the color values, gamma irradiation of 20 kGy did not affect the Dancheong and stability was maintained for five months. In addition, the fungicidal and insecticidal effect by less than 5 kGy gamma irradiation was conformed. Therefore, the optical and structural properties of Dancheong were maintained after gamma irradiation, which suggested that gamma irradiation can be used for the preservation of wooden cultural heritages painted with Dancheong.

  1. EPR investigation of some gamma-irradiated excipients

    NASA Astrophysics Data System (ADS)

    Aleksieva, Katerina; Yordanov, Nicola D.

    2012-09-01

    The results of electron paramagnetic resonance (EPR) studies on some excipients: lactose, microcrystalline cellulose (avicel), starch, dioxosilane (aerosil), talc and magnesium stearate before and after gamma-irradiation are reported. Before irradiation, all samples are EPR silent except talc. After gamma-irradiation, they show complex spectra except magnesium stearate, which is EPR silent. Studies show the influence of gamma-irradiation on EPR spectra and stability of gamma-induced radicals. Analysis of the EPR spectrum of gamma-irradiated talc shows that this material is radiation insensitive. Only lactose forms stable-free radicals upon gamma sterilization and can be used for identification of radiation processing for a long time period thereafter.

  2. Application of gamma irradiation for inhibition of food allergy

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Lee, Ju-Woon; Yook, Hong-Sun; Jo, Cheorun; Kim, Hee-Yun

    2002-03-01

    This study was carried out to evaluate the application of food irradiation technology as a method for reducing food allergy. Milk β-lactoglobulin, chicken egg albumin, and shrimp tropomyosin were used as model food allergens for experiments on allergenic and molecular properties by gamma irradiation. The amount of intact allergens in an irradiated solution was reduced by gamma irradiation depending upon the dose. These results showed that epitopes on the allergens were structurally altered by radiation treatment and that the irradiation technology can be applied to reduce allergenicity of allergic foods.

  3. Effect of gamma irradiation on the structure of fucoidan

    NASA Astrophysics Data System (ADS)

    Choi, Jong-il; Gu Lee, Sung; Jong Han, Se; Cho, Minho; Cheon Lee, Pyung

    2014-07-01

    The change of molecular structure of fucoidan by gamma irradiation was analyzed by spectral and chemical methods. Fucoidan samples with different molecular weights of 85, 30, 15, and 7 kDa were prepared by radiation degradation of 217 kDa fucoidan. In the molecular weight analysis, the polydispersity decreased by gamma radiation because of further degradation of higher weight molecules. Ultraviolet absorption and Fourier-transform infrared spectroscopy analyses were carried out to define the changes of the functional groups in fucoidan by gamma irradiation. Carboxyl groups and carbon double bonds increased by gamma irradiation; however, sulfate content remained unchanged. The granular fissures were observed from scanning electron microscopy in gamma-irradiated fucoidan.

  4. Sulphur flux through the sulphate assimilation pathway is differently controlled by adenosine 5'-phosphosulphate reductase under stress and in transgenic poplar plants overexpressing gamma-ECS, SO, or APR.

    PubMed

    Scheerer, Ursula; Haensch, Robert; Mendel, Ralf R; Kopriva, Stanislav; Rennenberg, Heinz; Herschbach, Cornelia

    2010-01-01

    Sulphate assimilation provides reduced sulphur for the synthesis of cysteine, methionine, and numerous other essential metabolites and secondary compounds. The key step in the pathway is the reduction of activated sulphate, adenosine 5'-phosphosulphate (APS), to sulphite catalysed by APS reductase (APR). In the present study, [(35)S]sulphur flux from external sulphate into glutathione (GSH) and proteins was analysed to check whether APR controls the flux through the sulphate assimilation pathway in poplar roots under some stress conditions and in transgenic poplars. (i) O-Acetylserine (OAS) induced APR activity and the sulphur flux into GSH. (ii) The herbicide Acetochlor induced APR activity and results in a decline of GSH. Thereby the sulphur flux into GSH or protein remained unaffected. (iii) Cd treatment increased APR activity without any changes in sulphur flux but lowered sulphate uptake. Several transgenic poplar plants that were manipulated in sulphur metabolism were also analysed. (i) Transgenic poplar plants that overexpressed the gamma-glutamylcysteine synthetase (gamma-ECS) gene, the enzyme catalysing the key step in GSH formation, showed an increase in sulphur flux into GSH and sulphate uptake when gamma-ECS was targeted to the cytosol, while no changes in sulphur flux were observed when gamma-ECS was targeted to plastids. (ii) No effect on sulphur flux was observed when the sulphite oxidase (SO) gene from Arabidopsis thaliana, which catalyses the back reaction of APR, that is the reaction from sulphite to sulphate, was overexpressed. (iii) When Lemna minor APR was overexpressed in poplar, APR activity increased as expected, but no changes in sulphur flux were observed. For all of these experiments the flux control coefficient for APR was calculated. APR as a controlling step in sulphate assimilation seems obvious under OAS treatment, in gamma-ECS and SO overexpressing poplars. A possible loss of control under certain conditions, that is Cd treatment

  5. Gamma irradiation influence on physical properties of milk proteins

    NASA Astrophysics Data System (ADS)

    Cieśla, K.; Salmieri, S.; Lacroix, M.; Tien, C. Le

    2004-09-01

    Gamma irradiation was found to be an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on calcium and sodium caseinates alone or combined with some globular proteins. Our current studies concern gamma irradiation influence on the physical properties of calcium caseinate-whey protein isolate-glycerol (1:1:1) solutions and gels, used for films preparation. Irradiation of solutions was carried out with Co-60 gamma rays applying 0 and 32 kGy dose. The increase in viscosity of solutions was found after irradiation connected to induced crosslinking. Lower viscosity values were detected, however, after heating of the solutions irradiated with a 32 kGy dose than after heating of the non-irradiated ones regarding differences in the structure of gels and resulting in different temperature-viscosity curves that were recorded for the irradiated and the non-irradiated samples during heating and cooling. Creation of less stiff but better ordered gels after irradiation arises probably from reorganisation of aperiodic helical phase and β-sheets, in particular from increase of β-strands, detected by FTIR. Films obtained from these gels are characterised by improved barrier properties and mechanical resistance and are more rigid than those prepared from the non-irradiated gels. The route of gel creation was investigated for the control and the irradiated samples during heating and the subsequent cooling.

  6. Thermoluminescence and dielectric response of gamma irradiated muscovite mica

    SciTech Connect

    Kaur, Sukhnandan Singh, Surinder Singh, Lakhwant; Lochab, S. P.

    2014-04-24

    The effect of gamma radiation dose on the thermoluminescence (TL) and dielectric properties of muscovite mica was studied. TL glow curves exhibited a single peak around 141 {sup 0}C and its activation energy was estimated to be about 0.89 eV. Different dielectric parameters like dielectric constant, dielectric loss and ac conductivity have been calculated in both pristine and gamma irradiated samples. These dielectric parameters have been studied as a function of irradiation dose.

  7. Effect of gamma ray irradiation on sodium borate single crystals

    NASA Astrophysics Data System (ADS)

    Kalidasan, M.; Asokan, K.; Baskar, K.; Dhanasekaran, R.

    2015-12-01

    In this work, the effects of 5 kGy, 10 kGy and 20 kGy doses of gamma ray irradiation on sodium borate, Na2[B4O5(OH)4]·(H2O)8 single crystals have been studied. Initially these crystals were grown by solution growth technique and identified as monoclinic using X-ray diffraction analysis. X-ray rocking curves confirm the formation of crystalline defects due to gamma rays in sodium borate single crystals. The electron paramagnetic resonance spectra have been recorded to identify the radicals created due to gamma ray irradiation in sodium borate single crystals. The thermoluminescence glow curves due to the defects created by gamma rays in this crystal have been observed and their kinetic parameters were calculated using Chen's peak shape method. The optical absorption increases and photoluminescence spectral intensity decreases for 5 kGy and 20 kGy doses gamma ray irradiated crystals compared to pristine and 10 kGy dose irradiated one. The effect of various doses of gamma rays on vibrational modes of the sodium borate single crystals was studied using FT-Raman and ATR-FTIR spectral analysis. The dielectric permittivity, conductance and dielectric loss versus frequency graphs of these crystals have been analyzed to know the effect of gamma ray irradiation on these parameters.

  8. Radiation Sterilization and Food Irradiation Using Gamma Radiation

    NASA Astrophysics Data System (ADS)

    O'Hara, Kevin

    2003-03-01

    Since the introduction of MDS Nordion's first irradiator in the early 1960's, a variety of gamma-processing systems has been developed. Each design is suited to a particular set of requirements - from high-throughput operations of diverse product lots to full automation or batch processing, all using gamma radiation. Gamma irradiator designs include the Centurion irradiator for temperature-sensitive food products like hamburgers and poultry; the Brevion, a compact batch irradiator providing flexibility, timeliness and simplicity on a whole new scale; a JS-10000 irradiator that operates in either automatic or batch mode to enable multipurpose product scheduling and optimum throughput; and, an irradiator that processes full pallets and is ideal for processing high-density products requiring excellent dose uniformity. These innovative irradiator designs help facilities to be more efficient, maximize operating time, improve product turnaround and minimize inventory levels. MDS Nordion's development of improved Point Kernel and Monte Carlo techniques is discussed, including their application in radiation source optimization, production irradiator design and process control. Absorbed-dose calculations also provide insight into the critical areas for dose mapping and routine monitoring, allowing for the optimum placement of dosimeters. Calculations may also be used to determine the absorbed-dose distribution within product, especially in areas of complex geometry such as material interfaces. The use of easily accessible, accurate and validated dose-calculation programs can be used to optimize the irradiation process. Key Words: dosimetry, irradiator design, dose calculation, modelling, modeling, process control, radiation source optimization.

  9. Effect of gamma irradiation on rice and its food products

    NASA Astrophysics Data System (ADS)

    Sung, Wen-Chieh

    2005-07-01

    Two milled indica rice varieties were exposed to gamma radiation with doses ranging from 0 to 1.0 kGy. The effects of gamma irradiation on rice flour pasting properties and the qualities of its food product, rice curd, were compared to the effects of storage. A dose of 1 kGy can decrease the flour paste viscosity and tenderize the texture of the rice curd to similar levels as those obtained after 12 months of storage. It was thus shown that gamma irradiation could shorten the indica rice aging time and improve the processing stability and quality of rice products.

  10. Raman and AFM study of gamma irradiated plastic bottle sheets

    NASA Astrophysics Data System (ADS)

    Ali, Yasir; Kumar, Vijay; Sonkawade, R. G.; Dhaliwal, A. S.

    2013-02-01

    In this investigation, the effects of gamma irradiation on the structural properties of plastic bottle sheet are studied. The Plastic sheets were exposed with 1.25MeV 60Co gamma rays source at various dose levels within the range from 0-670 kGy. The induced modifications were followed by micro-Raman and atomic force microscopy (AFM). The Raman spectrum shows the decrease in Raman intensity and formation of unsaturated bonds with an increase in the gamma dose. AFM image displays rough surface morphology after irradiation. The detailed Raman analysis of plastic bottle sheets is presented here, and the results are correlated with the AFM observations.

  11. Raman and AFM study of gamma irradiated plastic bottle sheets

    SciTech Connect

    Ali, Yasir; Kumar, Vijay; Dhaliwal, A. S.; Sonkawade, R. G.

    2013-02-05

    In this investigation, the effects of gamma irradiation on the structural properties of plastic bottle sheet are studied. The Plastic sheets were exposed with 1.25MeV {sup 60}Co gamma rays source at various dose levels within the range from 0-670 kGy. The induced modifications were followed by micro-Raman and atomic force microscopy (AFM). The Raman spectrum shows the decrease in Raman intensity and formation of unsaturated bonds with an increase in the gamma dose. AFM image displays rough surface morphology after irradiation. The detailed Raman analysis of plastic bottle sheets is presented here, and the results are correlated with the AFM observations.

  12. Fluorescence diagnostics for foods subjected to gamma irradiation

    NASA Astrophysics Data System (ADS)

    Kulawansa, Digala M.; Menzel, E. R.; Banford, H. M.

    1996-03-01

    We have examined the inherent fluorescence of pepper and cinnamon samples exposed to radiation from a 60Co gamma source. We find that in the pepper the fluorescence intensity increases with radiation dose and the ratio of fluorescence intensity at two specific wavelengths, 566 and 674 nm, increases with radiation dose. In contrast, in the cinnamon the distinction between unirradiated and irradiated is not clear. Our preliminary work on gamma ray irradiated pepper indicates that laser-induced fluorescence may be utilized to detect the absorbed dose of irradiation of food samples.

  13. Neutron and gamma irradiation damage to organic materials.

    SciTech Connect

    White, Gregory Von, II; Bernstein, Robert

    2012-04-01

    This document discusses open literature reports which investigate the damage effects of neutron and gamma irradiation on polymers and/or epoxies - damage refers to reduced physical chemical, and electrical properties. Based on the literature, correlations are made for an SNL developed epoxy (Epon 828-1031/DDS) with an expected total fast-neutron fluence of {approx}10{sup 12} n/cm{sup 2} and a {gamma} dosage of {approx}500 Gy received over {approx}30 years at < 200 C. In short, there are no gamma and neutron irradiation concerns for Epon 828-1031/DDS. To enhance the fidelity of our hypotheses, in regards to radiation damage, we propose future work consisting of simultaneous thermal/irradiation (neutron and gamma) experiments that will help elucidate any damage concerns at these specified environmental conditions.

  14. Neutron and gamma irradiation effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high-power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  15. Neutron and gamma irradiation effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  16. The study of gamma irradiation effects on poly (glycolic acid)

    NASA Astrophysics Data System (ADS)

    Rao Nakka, Rajeswara; Rao Thumu, Venkatappa; Reddy SVS, Ramana; Rao Buddhiraju, Sanjeeva

    2015-05-01

    We have investigated the effects of gamma irradiation on chemical structure, thermal and morphological properties of biodegradable semi-crystalline poly (glycolic acid) (PGA). PGA samples were subjected to irradiation treatment using a 60Co gamma source with a delivered dose of 30, 60 and 90 kGy, respectively. Gamma irradiation induces cleavage of PGA main chains forming ∼OĊH2 and ĊH2COO∼ radicals in both amorphous and crystalline regions. The free radicals formed in the amorphous region abstract atmospheric oxygen and convert them to peroxy radicals. The peroxy radical causes chain scission at the crystal interface through hydrogen abstraction from methylene groups forming the ∼ĊHCOO∼ (I) radical. Consequently, the observed electron spin resonance (ESR) doublet of irradiated PGA is assigned to (I). The disappearance of the ESR signal above 190°C indicates that free radicals are formed in the amorphous region and decay below the melting temperature of PGA. Fourier transform infrared and optical absorption studies confirm that the ? groups are not influenced by gamma irradiation. Differential scanning calorimetry (DSC) studies showed that the melting temperature of PGA decreased from 212°C to 202°C upon irradiation. Degree of crystallinity increased initially and then decreased with an increase in radiation as per DSC and X-ray diffraction studies. Irradiation produced changes in the physical properties of PGA as well as affecting the morphology of the material.

  17. Induction of Oral Tolerance by Gamma-Irradiated Ovalbumin Administration.

    PubMed

    Yang, Hui; Lee, Junglim; Seo, Ji Hyun; Oh, Kwang Hoon; Cho, Young Ho; Yoo, Yung Choon

    2016-01-01

    Oral administration of soluble antigen can induce peripheral tolerance to the antigen. This study was conducted to evaluate whether gamma-irradiated ovalbumin (OVA) can induce oral tolerance. To investigate this, we administrated intact or irradiated OVA to mice, induced allergic response using intact OVA and alum, then compared humoral and cellular immune responses. Mice treated with gammairradiated OVA had less OVA-specific IgE compared with those who were administered intact OVA. There was no difference in levels of OVA-specific IgG+A+M, IgG1, and IgG2a. Splenocytes of mice administered irradiated OVA showed similar OVA-specific T cell proliferation and secretion of IFN-γ and IL-4. However, there was an increase in IL-2 and a decrease of IL-6 secretion in mice treated with irradiated OVA. These results indicate that gamma-irradiated OVA have similar effects to intact OVA on antigen tolerance. PMID:27499658

  18. Induction of Oral Tolerance by Gamma-Irradiated Ovalbumin Administration

    PubMed Central

    Yang, Hui; Lee, Junglim; Seo, Ji Hyun; Oh, Kwang Hoon; Cho, Young Ho; Yoo, Yung Choon

    2016-01-01

    Oral administration of soluble antigen can induce peripheral tolerance to the antigen. This study was conducted to evaluate whether gamma-irradiated ovalbumin (OVA) can induce oral tolerance. To investigate this, we administrated intact or irradiated OVA to mice, induced allergic response using intact OVA and alum, then compared humoral and cellular immune responses. Mice treated with gammairradiated OVA had less OVA-specific IgE compared with those who were administered intact OVA. There was no difference in levels of OVA-specific IgG+A+M, IgG1, and IgG2a. Splenocytes of mice administered irradiated OVA showed similar OVA-specific T cell proliferation and secretion of IFN-γ and IL-4. However, there was an increase in IL-2 and a decrease of IL-6 secretion in mice treated with irradiated OVA. These results indicate that gamma-irradiated OVA have similar effects to intact OVA on antigen tolerance. PMID:27499658

  19. Health protection and food preservation by gamma irradiation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Results of several major studies on food systems for space missions beginning with Apollo 12 through Apollo-Soyuz and investigations of the application of irradiation to food for manned space flight are reported. The study of flight food systems involved the application of radurization (pasteurizing levels) doses of gamma irradiation to flour and bread supplied by Pepperidge Farms in advance of the missions. All flights from Apollo 12 through 17 carried irradiated fresh bread. On Apollo 17, cooperation with Natick Laboratories permitted the introduction of a ham sandwich using irradiated bread and irradiated sterile ham. Investigations centered on irradiated bread were conducted during the course of these missions. Studies were applied to the concept of improving fresh bread from the point of view of mold inhibition. The studies considered how irradiation could best be applied at what levels and on a variety of bread types. Throughout the studies of the application of gamma irradiation the emphasis was placed upon using low levels of irradiation in the pasteurizing or radurizing doses--under a Megarad. The primary goal was to determine if a public health benefit could be demonstrated using radurization along with food preservation and food quality improvements. The public health benefit would be parallel to that of pasteurization of milk as a concept. Publications are included providing the details of these observations, one dealing with the flour characteristics and the other dealing with the influence on fresh bread types. These demonstrate the major findings noted during the period of the studies examining bread.

  20. The pros and cons of polyethylene sterilization with gamma irradiation.

    PubMed

    Hopper, Robert H; Engh, C Anderson; Fowlkes, LaTonya B; Engh, Charles A

    2004-12-01

    This retrospective study evaluated the implant, patient and surgical factors associated with polyethylene wear for one type of porous-coated hemispheric total hip arthroplasty cup. Radiographic wear measurements among 567 Duraloc cups (512 patients) revealed that liners sterilized by gamma-irradiation wore 0.085 mm/year less than those that were sterilized by gas-plasma, a noncross-linking chemical surface treatment. The substantially decreased wear rate associated with gamma-irradiation was attributed to sterilization-induced polyethylene cross-linking. Shelf-aging adversely affected liners that were gamma irradiated in air. On average, highly crystalline Hylamer liners showed a 0.064 mm/year increase in wear rates for each year of shelf storage after terminal sterilization with gamma-irradiation in air. Among conventional Enduron liners, the effect of shelf aging after gamma-irradiation in air was more modest, increasing wear rates by 0.014 mm/year for each year of shelf storage. Because Hylamer's wear performance degraded at about five times the rate of Enduron's, the improved wear resistance associated with gamma-irradiation in air would be lost after 1.3 years of shelf aging for Hylamer compared with 6.1 years for Enduron. For every additional year of age at the time of surgery, the wear rate decreased by 0.003 mm/year. Increased body mass index, a preoperative diagnosis of inflammatory arthritis, and a ceramic femoral head also were associated with decreased wear rates. PMID:15577466

  1. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)

    SciTech Connect

    Clark, E.

    2013-09-13

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10°C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.

  2. Gamma irradiation treatment of cereal grains for chick diets

    SciTech Connect

    Campbell, G.L.; Classen, H.L.; Ballance, G.M.

    1986-04-01

    Wheat (W), triticale (T), hulled barley (HB), hull-less barley (HLB), hulled oats (HO), and hull-less oats (HLO) were gamma irradiated (/sup 60/Co) at 0, 3, 6 and 9 Mrad to study the effect of irradiation on the nutritional value of cereal grains for chicks. A significant curvilinear relationship between radiation dose and 3-wk body weight of chicks fed irradiated cereals was noted for T, HB, HLB, HO and HLO. Chicks fed W or T showed no effect or lower body weight, respectively, while body weights of chicks fed barley or oat samples were higher with irradiation. The improvement tended to be maximal at the 6 Mrad level. Irradiation significantly improved the gain-to-feed ratio for chicks fed either HO or HLO. Apparent fat retention and tibia ash were higher in chicks fed irradiated HLO than in those fed untreated HLO. In a second experiment chick body weight, apparent amino acid and fat retention, tibia ash, and gain-to-feed ratios were lower in chicks fed autoclaved (121 degrees C for 20 min) barley than in those fed untreated barley. Irradiation (6 Mrad) subsequent to autoclaving barley samples eliminated these effects. Irradiation appears to benefit cereals containing soluble or mucilagenous fiber types as typified by beta-glucan of barley and oats. These fibers appear prone to irradiation-induced depolymerization, as suggested by increased beta-glucan solubility and reduced extract viscosity for irradiated barley and oat samples.

  3. Survival Study of Zebrafish Embryos Under Gamma Irradiation

    NASA Astrophysics Data System (ADS)

    Mena, Pamela; Allende, Miguel; Morales, José Roberto

    2010-08-01

    Zebrafish embryos have interesting biological properties for the study of human diseases. The present work uses zebrafish embryos in a particular development state, to study biological effects due to gamma radiation, arising from a calibrated 60Co source. Initially, the lethal dose for fish embryos was determined and subsequent irradiations were performed at sub-lethal doses, in order to study more subtle effects.

  4. Gamma and electron-beam irradiation of cut flowers

    NASA Astrophysics Data System (ADS)

    Kikuchi, Olivia Kimiko

    2003-01-01

    Fresh cut flowers are commodities that require quarantine treatment for export/import. In the present work some cut flowers were irradiated in a gamma panoramic source and in an electron beam accelerator with doses up to 800 Gy, and the results for the radiation tolerance of the flowers are presented.

  5. Role of Sucrose in Gamma-irradiated Chrysanthemum Cut Flowers.

    PubMed

    Nakahara, K; Kikuchi, O K; Todoriki, S; Hosoda, H; Hayashi, T

    1998-01-01

    Vase solution containing 2% sucrose prevented the deterioration of chrysanthemum (Dendranthema grandiflorum Kitamura) cut flowers induced by gamma-rays at 750 Gy. Glucose, fructose, and sucrose in florets and leaves of irradiated chrysanthemums decreased more rapidly than those of unirradiated ones, when the cut chrysanthemums were held in a vase solution without sucrose. The sugar contents of florets and leaves and the respiratory rate of irradiated chrysanthemums held with sucrose remained at higher levels than those of unirradiated ones. Incorporation of (14)C from [(14)C]sucrose into CO2 was increased by irradiation. Incorporation of [α-(32)P]dTTP into trichloroacetic acid (TCA) insoluble substances in florets was increased by irradiation and by exogenous sucrose supply. These results suggest that sucrose in a vase solution was used as a respiratory substrate and facilitated the repair of radiation-induced damage, resulting in the extension of longevity of irradiated chrysanthemums.

  6. Sucrose synthesis in gamma irradiated sweet potato

    SciTech Connect

    Ailouni, S.; Hamdy, M.K.; Toledo, R.T.

    1987-01-01

    Effect of ..cap alpha..-irradiation carbohydrate metabolism was examined to elucidate mechanism of sucrose accumulation in sweet potato (SP). Enzymes examined were: ..beta..-amylase, phosphorylase, phosphoglucomutase, phosphoglucose isomerase, sucrose phosphate synthetase and sucrose synthetase. Irradiated SP (Red Jewell) sucrose was synthesized to yield 10.7% after 4 d PI. Activities of sugar synthesizing enzymes in irradiated SP were enhanced to different degrees using 100-200 Krad and 3 d PI at 24/sup 0/C. Phosphorylase and phosphoglucomutases specific activities reached 2.4 and 1.8 folds, respectively compared to control SP. ..beta..-amylase, phosphoglucose isomerase, sucrose synthetase and sucrose phosphate synthetase were also affected to yield 1.2, 1.3, 1.3 and 1.2 folds, respectively compared to controls. It is believed that amylase hydrolyzed starch to glucose which is converted to fructose by phosphoglucose isomerase. Sucrose is then formed by sucrose phosphate synthetase and/or sucrose synthetase leading to its accumulation. The irradiated SP was used for alcohol fermentation leading to 500 gal. of 200 proof ethanol/acre (from 500-600 bushels tuber/acre).

  7. The influence of Gamma Irradiation on flavonoïds content during storage of irradiated clementina

    NASA Astrophysics Data System (ADS)

    Oufedjikh, H.; Mahrouz, M.; Lacroix, M.; Amiot, M. J.; Taccini, M.

    1998-06-01

    The influence of Gamma irradiation on content of some important flavonoïds (flavonones glycosides and polymethoxylated flavones) was evaluated during storage of Moroccan clementina treated at a mean dose of 0.3 kGy and stored three months at 3'C. Results shows that at day one, gamma irradiation induced degradation of small quantities of these flavonoïds, however after 14 days of storage, the content of these compounds was significantly higher (p≤0.05) in irradiated samples. Irradiation stimulated biosynthesis of flavonoïds after 14 days of storage. Hesperidin was the major flavanones compounds in clementines. Nobiletin and Heptamethoxyflavone were the major polymethoxylated flavones in clementines. Our study demonstrated that the content of these compounds was significantly higher (p≤0.05) in irradiated samples.

  8. Rapid differentiation between gamma-irradiated and non irradiated potato tubers

    NASA Astrophysics Data System (ADS)

    Jona, Roberto; Fronda, Anna

    The use of gamma irradiation as commercial method for the preservation of fruits and vegetables calls for methods of differentiation between irradiated and non-irradiated foodstuffs. In a previous research, the polysaccharidic content of cell walls of irradiated tissue has been investigated, but it required rather long time to reach the result. A method devised to ascertain the vitality of cells has been applied to distinguish irradiated from non-irradiated potato tubers. 500 mg of tissue excised from tubers have been infiltrated with tetrazolium chloride 0.6% in phosphate buffer, pH 7.4. After 15 hrs of incubation at 30°C the treated tissues have been extracted with 95% ethanol whose O.D. has been measured at 530 mμ wavelength. The colour intensity of the alcohol allowed a very clearcut recognition of the irradiated tubers.

  9. Experimental qualification of a code for optimizing gamma irradiation facilities

    NASA Astrophysics Data System (ADS)

    Mosse, D. C.; Leizier, J. J. M.; Keraron, Y.; Lallemant, T. F.; Perdriau, P. D. M.

    Dose computation codes are a prerequisite for the design of gamma irradiation facilities. Code quality is a basic factor in the achievement of sound economic and technical performance by the facility. This paper covers the validation of a code by reference dosimetry experiments. Developed by the "Société Générale pour les Techniques Nouvelles" (SGN), a supplier of irradiation facilities and member of the CEA Group, the code is currently used by that company. (ERHART, KERARON, 1986) Experimental data were obtained under conditions representative of those prevailing in the gamma irradiation of foodstuffs. Irradiation was performed in POSEIDON, a Cobalt 60 cell of ORIS-I. Several Cobalt 60 rods of known activity are arranged in a planar array typical of industrial irradiation facilities. Pallet density is uniform, ranging from 0 (air) to 0.6. Reference dosimetry measurements were performed by the "Laboratoire de Métrologie des Rayonnements Ionisants" (LMRI) of the "Bureau National de Métrologie" (BNM). The procedure is based on the positioning of more than 300 ESR/alanine dosemeters throughout the various target volumes used. The reference quantity was the absorbed dose in water. The code was validated by a comparison of experimental and computed data. It has proved to be an effective tool for the design of facilities meeting the specific requirements applicable to foodstuff irradiation, which are frequently found difficult to meet.

  10. Effect of gamma irradiation on antinutritional factors in broad bean

    NASA Astrophysics Data System (ADS)

    Al-Kaisey, Mahdi T.; Alwan, Abdul-Kader H.; Mohammad, Manal H.; Saeed, Amjed H.

    2003-06-01

    The effect of gamma irradiation on the level of antinutritional factors (trypsin inhibitor (TI), phytic acid and oligosaccharides) of broad bean was investigated. The seeds were subjected to gamma irradiation at 0, 2.5, 5, 7.5 and 10 kGy, respectively using cobalt-60 gamma radiation with a dose rate 2.37 kGy/h. TI activity was reduced by 4.5%, 6.7%, 8.5% and 9.2% at 2.5, 5, 7.5 and 10 kGy, respectively. Meanwhile, irradiation at 10.2, 12.3, 15.4 and 18.2 kGy reduced the phytic acid content. The flatulence causing oligosaccharides were decreased as the radiation dose increased. The chemical composition (protein, oil, ash and total carbohydrates) of the tested seeds was determined. Gamma radiation seems to be a good procedure to improve the quality of broad bean from the nutritional point of view.

  11. Variation in electrical properties of gamma irradiated cadmium selenate nanowires

    NASA Astrophysics Data System (ADS)

    Chauhan, R. P.; Rana, Pallavi; Narula, Chetna; Panchal, Suresh; Choudhary, Ritika

    2016-07-01

    Preparation of low-dimensional materials attracts more and more interest in the last few years, mainly due to the wide field of potential commercial applications ranging from life sciences, medicine and biotechnology to communication and electronics. One-dimensional systems are the smallest dimension structures that can be used for efficient transport of electrons and thus expected to be critical to the function and integration of nanoscale devices. Nanowires with well controlled morphology and extremely high aspect ratio can be obtained by replicating a nanoporous polymer ion-track membrane with cylindrical pores of controlled dimensions. With this technique, materials can be deposited within the pores of the membrane by electrochemical reduction of the desired ion. In the present study, cadmium selenate nanowires were synthesized potentiostatically via template method. These synthesized nanowires were then exposed to gamma rays by using a 60Co source at the Inter University Accelerator Centre, New Delhi, India. Structural, morphological, electrical and elemental characterizations were made in order to analyze the effect of gamma irradiation on the synthesized nanowires. I-V measurements of cadmium selenate nanowires, before and after irradiation were made with the help of Keithley 2400 source meter and Ecopia probe station. A significant change in the electrical conductivity of cadmium selenate nanowires was found after gamma irradiation. The crystallography of the synthesized nanowires was also studied using a Rigaku X-ray diffractrometer equipped with Cu-Kα radiation. XRD patterns of irradiated samples showed no variation in the peak positions or phase change.

  12. Inactivation of Coxiella burnetti by gamma irradiation

    SciTech Connect

    Scott, G.H.; McCaul, T.F.; Williams, J.C.

    1989-01-01

    The gamma radiation inactivation kinetics for Coxiella burnetii at - 79 C were exponential. The radiation dose needed to reduce the number of infective C. burnetii by 90% varied from 0-64 to 1.2 kGy depending on the phase of hte micro-organism, purity of the culture and composition of suspending menstruum. The viability of preparations containing C. burnetti was completely abolished by 10 kGy without diminishing antigenicity or ability to elicit a protective immune response in vaccinated mice. Immunocytochemical examinations using monoclonal antibodies and electron microscopy demonstrated that radiation doses of 20 kGy did not alter cell-wall morphology or cell-surface antigenic epitopes.

  13. Enhanced release of bone morphogenetic proteins from demineralized bone matrix by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Sung, Nak-Yun; Choi, Jong-il

    2015-06-01

    Gamma irradiation is a useful method for sterilizing demineralized bone matrix (DBM), but its effect on the osteoinductivity of DBM is still controversial. In this study, the osteoinductive activity of gamma-irradiated DBM was examined using a mouse myoblastic cell line (C2C12). DBM was extracted from adult bovine bone and was irradiated at a dose of 25 kGy using a 60cobalt gamma-irradiator. Cell proliferation with DBM was not affected by gamma-irradiation, but alkaline phosphatase and osteocalcin productions were significantly increased in C2C12 cell groups treated with gamma-irradiated DBM. It was reasoned that bone morphogenetic proteins were more efficiently released from gamma-irradiated DBM than from the non-irradiated control. This result suggests the effectiveness of radiation sterilization of bone implants

  14. Enhancement of Antioxidant and Isoflavones Concentration in Gamma Irradiated Soybean

    PubMed Central

    Popović, Boris M.; Štajner, Dubravka; Mandić, Anamarija; Čanadanović-Brunet, Jasna; Kevrešan, Slavko

    2013-01-01

    Serbian soybean genotype Ana was gamma irradiated at doses of 1, 2, 4, and 10 kGy in order to evaluate the influence of gamma irradiation on isoflavone (genistein, daidzein, and their glycosides genistin and daidzin) contents and hydroxyl radical scavenging effect (HRSE). The increase in genistin and daidzin contents as well as antioxidant activities was observed especially at doses of 4 and 10 kGy. Results were also compared with our previous results relating to total phenol content (TPC), DPPH radical scavenger capacity (DPPH RSC), and ferric reducing antioxidant power (FRAP). Our results indicated that doses up to 10 kGy improve the antioxidant activities of soybean and also nutritional quality with respect to isoflavone content. All results were analyzed by multivariate techniques (correlation matrix calculation and autoscaling transformation of data). Significant positive correlations were observed between genistin, daidzin, DPPH RSC, and HRSE. PMID:24298214

  15. Spectroscopic investigation of PVA-TIO2 membranes gamma irradiated

    NASA Astrophysics Data System (ADS)

    Todica, Mihai; Udrescu, Luciana; Damian, Grigore; Astilean, Simion

    2013-07-01

    The modifications of the PVA-TiO2 membranes exposed to gamma radiations were investigated by ESR and XRD methods. The ESR spectra show the appearance of a strong signal associated with the breaking of the polymeric chain and the appearance of the unpaired electrons. The mechanism is influenced by the concentration of TiO2. The modification of local order of the polymeric chains after irradiation is confirmed by XRD method.

  16. gamma-Irradiation of PEGd,lPLA and PEG-PLGA multiblock copolymers. I. Effect of irradiation doses.

    PubMed

    Dorati, R; Colonna, C; Serra, M; Genta, I; Modena, T; Pavanetto, F; Perugini, P; Conti, B

    2008-01-01

    To evaluate the effects of different gamma irradiation doses on PEGd,lPLA and PEG-PLGA multiblock copolymers. The behaviour of the multiblock copolymers to irradiation was compared to that of PLA, PLGA polymers. PEGd,lPLA, PEG-PLGA, PLA and PLGA polymers were irradiated by using a (60)Co irradiation source at 5, 15, 25 and 50 kGy total dose. Characterization was performed on all samples before and after irradiation, by nuclear magnetic resonance (NMR), infrared absorption spectrophotometry (FTIR) and gel permeation chromatography (GPC). The effect of gamma irradiation on polymer stability was also evaluated. Results of NMR and FTIR suggest an increase in -OH and -COOH groups, attributed to scission reactions induced by irradiation treatment. Data of GPC analysis showed that the weight average molecular weight (Mw) of polymer samples decreased with increasing irradiation dose. The extent of Mw degradation expressed as percentage of Mw reduction was more prominent for polymers with high molecular weight as PEGd,lPLA and PLA. The dominant effect of gamma-irradiation on both polymer samples was chain scission. The multiblock copolymer PEGd,lPLA presented higher sensitivity to irradiation treatment with respect to PLA, likely due to the presence of PEG in the matrix. The effect of gamma irradiation continues over a much longer period of time after gamma irradiation has been performed. It is suggested that the material reacts with oxygen to form peroxyl free radicals, which may further undergo degradation reactions during storage after irradiation. PMID:18528761

  17. White spot syndrome virus inactivation study by using gamma irradiation

    NASA Astrophysics Data System (ADS)

    Heidareh, Marzieh; Sedeh, Farahnaz Motamedi; Soltani, Mehdi; Rajabifar, Saeed; Afsharnasab, Mohammad; Dashtiannasab, Aghil

    2014-09-01

    The present study was conducted to investigate the effect of gamma irradiation on white spot syndrome virus (WSSV). White spot syndrome virus is a pathogen of major economic importance in cultured penaeid shrimp industries. White spot disease can cause mortalities reaching 100% within 3-10 days of gross signs appearing. During the period of culture, immunostimulant agents and vaccines may provide potential methods to protect shrimps from opportunistic and pathogenic microrganisms. In this study, firstly, WSSV was isolated from infected shrimp and then multiplied in crayfish. WSSV was purified from the infected crayfish haemolymph by sucrose gradient and confirmed by transmission electron microscopy. In vivo virus titration was performed in shrimp, Penaeus semisulcatus. The LD50 of live virus stock was calculated 10 5.4/mL. Shrimp post-larvae (1-2 g) were treated with gamma-irradiated (different doses) WSSV (100 to 10-4 dilutions) for a period of 10 days. The dose/survival curve for irradiated and un-irradiated WSSV was drawn; the optimum dose range for inactivation of WSSV and unaltered antigenicity was obtained 14-15 kGy. This preliminary information suggests that shrimp appear to benefit from treatment with gammairradiated WSSV especially at 14-15 KGy.

  18. Chemical investigation of gamma-irradiated saffron (Crocus sativus L.).

    PubMed

    Zareena, A V; Variyar, P S; Gholap, A S; Bongirwar, D R

    2001-02-01

    Changes in aroma and coloring properties of saffron (Crocus sativus) after gamma-irradiation at doses of 2.5 and 5 kGy (necessary for microbial decontamination) were investigated. The volatile essential oil constituents responsible for aroma of the spice were isolated by steam distillation and then subsequently analyzed by gas chromatography/mass spectrometry (GC/MS). No significant qualitative changes were observed in these constituents upon irradiation, although a trained sensory panel could detect slight quality deterioration at a dose of 5 kGy. Carotene glucosides that impart color to the spice were isolated by solvent extraction and then subjected to thin-layer chromatography and high-performance liquid chromatography (HPLC). Fractionation of the above pigments into aglycon and glucosides was achieved by using ethyl acetate and n-butanol, respectively. Analysis of these fractions by HPLC revealed a decrease in glucosides and an increase in aglycon content in irradiated samples. The possibility of degradation of pigments during gamma irradiation is discussed.

  19. Human cytomegalovirus replicates in gamma-irradiated fibroblasts

    SciTech Connect

    Shanley, J.D.

    1986-12-01

    Because of the unique interdependence of human cytomegalovirus (HCMV) and the physiological state of the host cell, we evaluated the ability of human foreskin fibroblasts (HFF), exposed to gamma radiation, to support HCMV growth. Irradiation of HFF with 2,500 rADS prevented cellular proliferation and suppressed cellular DNA, but not RNA or protein synthesis. Treatment of HFF cells with 2,500 rADS 6 or 48 hours prior to infection did not alter the time course or virus yield during HCMV replication. Virus plaquing efficiency in irradiated cells was comparable to that of nonirradiated cells. As judged by thymidine incorporation and BUdR inhibition of virus replication, HCMV infection induced both thymidine kinase activity and host cell DNA synthesis in irradiated cells. In addition, virus could be recovered from HFF exposed to radiation 0-2 days after infection with HCMV. These studies indicate that the damage to cells by gamma irradiation does not alter the capacity of host cells to support HCMV replication.

  20. TEST RESULTS FROM GAMMA IRRADIATION OF ALUMINUM OXYHYDROXIDES

    SciTech Connect

    Fisher, D.; Westbrook, M.; Sindelar, R.

    2012-02-01

    Hydrated metal oxides or oxyhydroxides boehmite and gibbsite that can form on spent aluminum-clad nuclear fuel assemblies during in-core and post-discharge wet storage were exposed as granular powders to gamma irradiation in a {sup 60}Co irradiator in closed laboratory test vessels with air and with argon as separate cover gases. The results show that boehmite readily evolves hydrogen with exposure up to a dose of 1.8 x 10{sup 8} rad, the maximum tested, in both a full-dried and moist condition of the powder, whereas only a very small measurable quantity of hydrogen was generated from the granular powder of gibbsite. Specific information on the test setup, sample characteristics, sample preparation, irradiation, and gas analysis are described.

  1. Chemometric characterization of gamma irradiated chestnuts from Turkey

    NASA Astrophysics Data System (ADS)

    Barreira, João C. M.; Antonio, Amilcar L.; Günaydi, Tugba; Alkan, Hasan; Bento, Albino; Luisa Botelho, M.; Ferreira, Isabel C. F. R.

    2012-09-01

    Chestnut (Castanea sativa Miller) is a valuable natural resource, with high exportation levels. Due to their water content, chestnuts are susceptible to storage problems like dehydration or development of insects and microorganisms. Irradiation has been revealing interesting features to be considered as an alternative conservation technology, increasing food products shelf-life. Any conservation methodology should have a wide application range. Hence, and after evaluating Portuguese cultivars, the assessment of irradiation effects in foreign cultivars might act as an important indicator of the versatility of this technology. In this work, the effects of gamma irradiation (0.0, 0.5 and 3.0 kGy) on proximate composition, sugars, fatty acids (FA) and tocopherols composition of Turkish chestnuts stored at 4 °C for different periods (0, 15 and 30 days) were evaluated. Regarding proximate composition, the storage time (ST) had higher influence than the irradiation dose (ID), especially on fat, ash, carbohydrates and energetic value. Sucrose exhibited similar behavior in response to the assayed ST and ID. The prevalence of ST influence was also verified for FA, tocopherols and sucrose. Lauric, palmitoleic and linolenic acids were the only FA that underwent some differences with ID. Saturated, monounsaturated and polyunsaturated fatty acids levels were not affected either by storage or irradiation. α-Tocopherol was the only vitamer with significant differences among the assayed ST and ID. Overall, Turkish cultivars showed a compositional profile closely related with Portuguese cultivars, and seemed to confirm that gamma irradiation in the applied doses did not change chestnut chemical and nutritional composition.

  2. Improvement of saccharification process for bioethanol production from Undaria sp. by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Yoon, Minchul; Choi, Jong-il; Lee, Ju-Woon; Park, Don-Hee

    2012-08-01

    Recently, many research works have reported on improvements to the saccharification process that increase bioethanol production from cellulosic materials. Gamma irradiation has been studied as an effective method for the depolymerization of complex polysaccharides. In this study, the effect of gamma irradiation on saccharification of Undaria biomass for bioethanol production was investigated. The Undaria biomass was irradiated at doses of 0, 10, 50, 100, 200 and 500 kGy and then hydrolyzed using sulfuric acid. The effects of gamma irradiation were measured through microscopic analysis to determine morphological changes and concentration of the reducing sugar of hydrolysates. Microscopic images show that gamma irradiation causes structure breakage of the Undaria cell wall. The concentration of reducing sugar of hydrolysates significantly increased as a result of gamma irradiation, with or without acid hydrolysis. These results indicate that the combined method of gamma irradiation with acid hydrolysis can significantly improve the saccharification process for bioethanol production from marine algae materials.

  3. Identification of gamma-irradiated fruit juices by EPR spectroscopy

    NASA Astrophysics Data System (ADS)

    Aleksieva, K. I.; Dimov, K. G.; Yordanov, N. D.

    2014-10-01

    The results of electron paramagnetic resonance (EPR) study on commercially available juices from various fruits and different fruit contents: 25%, 40%, 50%, and 100%, homemade juices, nectars and concentrated fruit syrups, before and after gamma-irradiation are reported. In order to remove water from non- and irradiated samples all juices and nectars were filtered; the solid residue was washed with alcohol and dried at room temperature. Only concentrated fruit syrups were dried for 60 min at 40 °C in a standard laboratory oven. All samples under study show a singlet EPR line with g=2.0025 before irradiation with exception of concentrated fruit syrups, which are EPR silent. Irradiation of juice samples gives rise to complex EPR spectra which gradually transferred to “cellulose-like” EPR spectrum from 25% to 100% fruit content. Concentrated fruit syrups show typical “sugar-like“ spectra due to added saccharides. All EPR spectra are characteristic and can prove radiation treatment. The fading kinetics of radiation-induced EPR signals were studied for a period of 60 days after irradiation.

  4. Improvement of colour strength and colourfastness properties of gamma irradiated cotton using reactive black-5

    NASA Astrophysics Data System (ADS)

    Ahmad Bhatti, Ijaz; Adeel, Shahid; Nadeem, Raziya; Asghar, Toheed

    2012-03-01

    The dyeing behaviour of gamma irradiated cotton fabric using Reactive Black-5 dye powder has been investigated. The mercerized, bleached and plain weaved cotton fabric was irradiated to different absorbed doses of 100, 200, 300, 400, 500 and 600 Gy using Co-60 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature of dyeing, time of dyeing and pH of dyeing solutions were optimised. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organisation (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It is found that gamma irradiated cotton dyed with Reactive Black-5 has not only improved the colour strength but also enhanced the rating of fastness properties.

  5. Gamma-ray irradiation of ohmic MEMS switches

    NASA Astrophysics Data System (ADS)

    Maciel, John J.; Lampen, James L.; Taylor, Edward W.

    2012-10-01

    Radio Frequency (RF) Microelectromechanical System (MEMS) switches are becoming important building blocks for a variety of military and commercial applications including switch matrices, phase shifters, electronically scanned antennas, switched filters, Automatic Test Equipment, instrumentation, cell phones and smart antennas. Low power consumption, large ratio of off-impedance to on-impedance, extreme linearity, low mass, small volume and the ability to be integrated with other electronics makes MEMS switches an attractive alternative to other mechanical and solid-state switches for a variety of space applications. Radant MEMS, Inc. has developed an electrostatically actuated broadband ohmic microswitch that has applications from DC through the microwave region. Despite the extensive earth based testing, little is known about the performance and reliability of these devices in space environments. To help fill this void, we have irradiated our commercial-off-the-shelf SPST, DC to 40 GHz MEMS switches with gamma-rays as an initial step to assessing static impact on RF performance. Results of Co-60 gamma-ray irradiation of the MEMS switches at photon energies ≥ 1.0 MeV to a total dose of ~ 118 krad(Si) did not show a statistically significant post-irradiation change in measured broadband, RF insertion loss, insertion phase, return loss and isolation.

  6. Optical fiber sensor for low dose gamma irradiation monitoring

    NASA Astrophysics Data System (ADS)

    de Andrés, Ana I.; Esteban, Ã.`scar; Embid, Miguel

    2016-05-01

    An optical fiber gamma ray detector is presented in this work. It is based on a Terbium doped Gadolinium Oxysulfide (Gd2O2S:Tb) scintillating powder which cover a chemically etched polymer fiber tip. This etching improves the fluorescence gathering by the optical fiber. The final diameter has been selected to fulfill the trade-off between light gathering and mechanical strength. Powder has been encapsulated inside a microtube where the fiber tip is immersed. The sensor has been irradiated with different air Kerma doses up to 2 Gy/h with a 137Cs source, and the spectral distribution of the fluorescence intensity has been recorded in a commercial grade CCD spectrometer. The obtained signal-to-noise ratio is good enough even for low doses, which has allowed to reduce the integration time in the spectrometer. The presented results show the feasibility for using low cost equipment to detect/measure ionizing radiation as gamma rays are.

  7. Influence of irradiation upon few-layered graphene using electron-beams and gamma-rays

    SciTech Connect

    Wang, Yuqing; Feng, Yi Mo, Fei; Qian, Gang; Chen, Yangming; Yu, Dongbo; Wang, Yang; Zhang, Xuebin

    2014-07-14

    Few-layered graphene (FLG) is irradiated by electron beams and gamma rays. After 100 keV electron irradiation, the edges of FLG start bending, shrinking, and finally generate gaps and carbon onions due to sputtering and knock-on damage mechanism. When the electron beam energy is increased further to 200 keV, FLG suffers rapid and catastrophic destruction. Unlike electron irradiation, Compton effect is the dominant damage mechanism in gamma irradiation. The irradiation results indicate the crystallinity of FLG decreases first, then restores as increasing irradiation doses, additionally, the ratio (O/C) of FLG surface and the relative content of oxygen groups increases after irradiation.

  8. Resistance of some common fungi to gamma irradiation

    SciTech Connect

    Saleh, Y.G.; Mayo, M.S.; Ahearn, D.G.

    1988-08-01

    Ten species of fungi representing the genera Alternaria, Aspergillus, Caldosporium, Curvularia, Fusarium, and Penicillium were examined for their relative resistance to gamma irradiation from a /sup 137/Cs source. Inactivation doses for dematiaceous fungi in agar medium ranged from 0.6 to greater than 1.7 megarads, whereas those for moniliaceous fungi were less than 0.3 megarad. D10 values (the dose required to reduce the inoculum by 1 log) for Curvularia geniculata (greater than 0.29 megarad) exceeded those for control spores of Bacillus pumilus (0.15 megarad).

  9. EPR studies of gamma-irradiated taurine single crystals

    NASA Astrophysics Data System (ADS)

    Bulut, A.; Karabulut, B.; Tapramaz, R.; Köksal, F.

    2000-04-01

    An EPR study of gamma-irradiated taurine [C 2H 7NO 3S] single crystal was carried out at room temperature. The EPR spectra were recorded in the three at mutually perpendicular planes. There are two magnetically distinct sites in monoclinic lattice. The principle values of g and hyperfine constants for both sites were calculated. The results have indicated the presence of 32ṠO -2 and 33ṠO -2 radicals. The hyperfine values of 33ṠO -2 radical were used to obtain O-S-O bond angle for both sites.

  10. Gamma Irradiation of Magnetoresistive Sensors for Planetary Exploration

    PubMed Central

    Sanz, Ruy; Fernández, Ana B.; Dominguez, Jose A.; Martín, Boris; Michelena, Marina D.

    2012-01-01

    A limited number of Anisotropic Magnetoresistive (AMR) commercial-off-the-shelf (COTS) magnetic sensors of the HMC series by Honeywell, with and without integrated front-end electronics, were irradiated with gamma rays up to a total irradiation dose of 200 krad (Si), following the ESCC Basic Specification No. 22900. Due to the magnetic cleanliness required for these tests a special set-up was designed and successfully employed. Several parameters of the sensors were monitored during testing and the results are reported in this paper. The authors conclude that AMR sensors without front-end electronics seem to be robust against radiation doses of up to 200 krad (Si) with a dose rate of 5 krad (Si)/hour and up to a resolution of tens of nT, but sensors with an integrated front-end seem to be more vulnerable to radiation. PMID:22666039

  11. Chemical constituents of Panax ginseng exposed to. gamma. irradiation

    SciTech Connect

    Kwon, Joongho; Belanger, J.M.R.; Sigouin, M.; Lanthier, J.; Willemot, C.; Pare, J.R.J. )

    1990-03-01

    Chemical constituents were monitored to assess the biochemical and nutritional safety of Panax ginseng powders that were irradiated at doses of 1-10 kGy. Quantitative analysis has shown that the main effective components - saponins - are not altered by {sup 60}Co {gamma} irradiation. Ginsenoside-Rg{sub 1} was not affected by the treatment. Negligible changes were observed in the free carbohydrate contents. Doses of more than 5 kGy caused significant decreases in sulfur-containing amino acids and in tyrosine. At doses of 10 kGy, free amino acids, such as proline and lysine, showed an appreciable increase. The composition in minerals was not altered irrespective of the applied doses.

  12. gamma-Irradiation effects on the thermal decomposition behaviour and IR absorption spectra of piperacillin

    NASA Astrophysics Data System (ADS)

    Mahfouz, R. M.; Gaffar, M. A.; Abu El-Fadl, A.; Hamad, Ar. G. K.

    2003-11-01

    The thermal decomposition behaviour of unirradiated and pre-gamma-irradiated piperacillin (pipril) as a semi-synthetic penicillin antibiotic has been studied in the temperature range of (273-1072 K). The decomposition was found to proceed through three major steps both for unirradiated and gamma-irradiated samples. Neither appearance nor disappearance of new bands in the IR spectrum of piperacillin was recorded as a result of gamma-irradiation but only a decrease in the intensity of most bands was observed. A degradation mechanism was suggested to explain the bond rupture and the decrease in the intensities of IR bands of gamma-irradiated piperacillin.

  13. EPR study on non- and gamma-irradiated herbal pills

    NASA Astrophysics Data System (ADS)

    Aleksieva, K.; Lagunov, O.; Dimov, K.; Yordanov, N. D.

    2011-06-01

    The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048±0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show "cellulose-like" EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

  14. Recovery of the Brookhaven gamma forest following 18 years' irradiation

    SciTech Connect

    Kroot, I.B.

    1987-07-01

    Vegetative growth at the oak-pine forest at Brookhaven National Laboratory was examined 2-5 years following cessation of chronic irradiation from a 9500 Ci Cesium-137 gamma source. Zonation of vegetation, first seen early in the irradiation period, remains strongly evident. Unusual patterns of vegetative recovery include: a failure of a dense Carex (sedge) zone to spread into the adjacent devastated zone; a decrease in lichen density from that seen during irradiation, with no discernible cause; and significant persistent changes in soil P levels in the devastated zone, correlated with differential growth of an annual composite species. Recovery is marked by a rapid vegative spread of Rubus alleghenensis and Populus tremuloides into the devastated zone; almost complete dominance by Carex and Rubus with the former Carex zone; and a slow reinvasion by the late successional oak and pine species. Comparisons with data from surveys taken during the irradiation period show ( in all zones except the devastated zone) a significant decrease in species diversity during the recovery period.

  15. Effect of Low Dose Gamma Irradiation together with Lipid A on Human Leukocytes Activities In Vitro

    NASA Astrophysics Data System (ADS)

    Belyakova, E.; Dubnickova, M.; Boreyko, A.

    2010-01-01

    The influence of gamma irradiation and of Lipid A from Escherichia coli on phagocytosis, lyzosyme and peroxidase activities of human leukocytes, in vitro was investigated. Leukocytes samples were irradiated with 1 and 5 Gy, respectively. The number of irradiated leukocytes was decreased in the irradiated samples. Only samples with additive Lipid A were not damaged by irradiation. The Lipid A had positive influence on biological activities of the irradiated leukocytes.

  16. Effects of gamma irradiation on physicochemical properties of Korean red ginseng powder

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Yook, Hong-Sun; Kwon, Oh-Jin; Kang, Il-Jun

    1997-04-01

    Gamma irradiation was applied to Korean red ginseng powder to improve its quality. Major physicochemical properties (approximate composition, pH, acidity, browning pigment, hydrogen donating activity, fatty acids, minerals and saponin) were not significantly changed by gamma irradiation up to 10 kGy. The TBA value was increased depending on the increment of irradiation dose level. In free amino acids, threonine was increased while, serine and glutamic acid were decreased by gamma irradiation. In total amino acids, total contents were not significantly changed by gamma irradiation though tyrosine was slightly decreased P ⩽ 0.05. In free sugar, glucose, sucrose and maltose were significantly increased by 7.5 and 10 kGy gamma irradiation P ⩽ 0.05

  17. Selection of Novel Cowpea Genotypes Derived through Gamma Irradiation.

    PubMed

    Horn, Lydia N; Ghebrehiwot, Habteab M; Shimelis, Hussein A

    2016-01-01

    Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought. Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors. The objective of this study was to identify agronomically desirable cowpea genotypes after mutagenesis using gamma irradiation. Seeds of three traditional cowpea varieties widely grown in Namibia including Nakare (IT81D-985), Shindimba (IT89KD-245-1), and Bira (IT87D-453-2) were gamma irradiated with varied doses and desirable mutants were selected from M2 through M6 generations. Substantial genetic variability was detected among cowpea genotypes after mutagenesis across generations including in flowering ability, maturity, flower and seed colors and grain yields. Ten phenotypically and agronomically stable novel mutants were isolated at the M6 each from the genetic background of the above three varieties. The selected promising mutants' lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments. The novel cowpea genotypes selected through the study are valuable genetic resources for genetic enhancement and breeding. PMID:27148275

  18. Selection of Novel Cowpea Genotypes Derived through Gamma Irradiation

    PubMed Central

    Horn, Lydia N.; Ghebrehiwot, Habteab M.; Shimelis, Hussein A.

    2016-01-01

    Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought. Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors. The objective of this study was to identify agronomically desirable cowpea genotypes after mutagenesis using gamma irradiation. Seeds of three traditional cowpea varieties widely grown in Namibia including Nakare (IT81D-985), Shindimba (IT89KD-245-1), and Bira (IT87D-453-2) were gamma irradiated with varied doses and desirable mutants were selected from M2 through M6 generations. Substantial genetic variability was detected among cowpea genotypes after mutagenesis across generations including in flowering ability, maturity, flower and seed colors and grain yields. Ten phenotypically and agronomically stable novel mutants were isolated at the M6 each from the genetic background of the above three varieties. The selected promising mutants’ lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments. The novel cowpea genotypes selected through the study are valuable genetic resources for genetic enhancement and breeding. PMID:27148275

  19. Albumin grafting on biomaterial surfaces using gamma-irradiation

    SciTech Connect

    Kamath, K.R.

    1993-01-01

    Surface modification has been used extensively in various fields to introduce desirable surface properties without affecting the bulk properties of the material. In the area of biomaterials, the approach of surface modification offers an effective alternative to the synthesis of new biomaterials. The specific objective of this study was to modify different biomaterial surfaces by albumin grafting to improve their blood compatibility. The modified surfaces were characterized for surface-induced platelet activation and thrombus formation. This behavior was correlated with the conditions used for grafting. In particular, albumin was functionalized to introduce pendant double bonds into the molecule. The functionalized albumin was covalently attached to various surfaces, such as dimethyldichlorosilane-coated glass, polypropylene, polycarbonate, poly(vinyl chloride), and polyethylene by gamma-irradiation. Platelet adhesion and activation on these surfaces was examined using video microscopy and scanning electron microscopy. The extent of grafting was found to be dependent on the albumin concentration used for adsorption and the gamma-irradiation time. Release of the grafted albumin during exposure to blood was minimal. The albumin-grafted fibers maintained their thromboresistant properties even after storage at elevated temperatures for prolonged time periods. Finally, the approach was used to graft albumin on the PLEXUS Adult Hollow Fiber Oxygenators (Shiley). The blood compatibility of the grafted oxygenators improved significantly when compared to controls.

  20. Selection of Novel Cowpea Genotypes Derived through Gamma Irradiation.

    PubMed

    Horn, Lydia N; Ghebrehiwot, Habteab M; Shimelis, Hussein A

    2016-01-01

    Cowpea (Vigna unguiculata [L.] Walp.) yields are considerably low in Namibia due to lack of improved varieties and biotic and abiotic stresses, notably, recurrent drought. Thus, genetic improvement in cowpea aims to develop cultivars with improved grain yield and tolerance to abiotic and biotic stress factors. The objective of this study was to identify agronomically desirable cowpea genotypes after mutagenesis using gamma irradiation. Seeds of three traditional cowpea varieties widely grown in Namibia including Nakare (IT81D-985), Shindimba (IT89KD-245-1), and Bira (IT87D-453-2) were gamma irradiated with varied doses and desirable mutants were selected from M2 through M6 generations. Substantial genetic variability was detected among cowpea genotypes after mutagenesis across generations including in flowering ability, maturity, flower and seed colors and grain yields. Ten phenotypically and agronomically stable novel mutants were isolated at the M6 each from the genetic background of the above three varieties. The selected promising mutants' lines are recommended for adaptability and stability tests across representative agro-ecologies for large-scale production or breeding in Namibia or similar environments. The novel cowpea genotypes selected through the study are valuable genetic resources for genetic enhancement and breeding.

  1. A Study on Gamma Irradiation Synthesis of Copper Nanoparticles

    SciTech Connect

    Ahmad, Shahrul Izwan Bin; Ahmad, Md. Soot Bin Hj.; Radiman, Shahidan Bin

    2009-06-01

    A study on the effect of gamma radiation dose and dose rate on the yield of copper nanoparticles produced had been done. Its objective is to show the relationship between the absorbed doses with the yield of production. The copper sulphate solution is prepared with addition of ethanol as radical scavenger. Then the solution is bubbled with nitrogen for before being irradiated at different absorbed dose and dose rate. There are five different dose rates being used in this experiment. Atomic absorption spectroscopy (AAS) was used to detect directly the quantity of copper nanoparticles produced. The AAS results show positive linear relationship between the yields of copper nanoparticles with increasing absorbed dose. Yield of production show independency with dose rate at every absorbed dose. AAS result is supported with UV-Vis analysis data on the supernatant from irradiated products. Transmission electron microscope (TEM) confirms the existence of copper nanoparticles in all samples that being irradiated at absorbed dose of 100 kGy. The size of nanoparticles is range from 2 to 10 nm. Peak from the XRD analysis show the existence of pure copper.

  2. [The radiation-increased synthesis of phytochelatins in roots of gamma-irradiated barley seedlings].

    PubMed

    Danilin, I A; Dikarev, V G; Geras'kin, S A

    2004-01-01

    It was shown that gamma-irradiation and cadmium nitrate increased synthesis of phytochelatins in roots of barley seedlings. The stimulation of synthesis of phytochelatins in gamma-irradiated plants was shown for the first time. The results obtained indicate more important role of phytochelatins in intercellular metabolism than heavy-metal-binding.

  3. Gamma irradiation of corn starches with different amylose-to-amylopectin ratio.

    PubMed

    Chung, Kok-Heung; Othman, Zainon; Lee, Jau-Shya

    2015-10-01

    Corn starches with different amylose-to-amylopectin ratio (waxy, normal, Hylon V, and Hylon VII) were treated with five doses of gamma irradiation (1, 5, 10, 25, and 50 kGy). The effects of gamma irradiation on the physicochemical properties of starch samples were investigated. Waxy samples showed an increase of amylose-like fractions when irradiated at 10 kGy. The reduction in apparent amylose content increased with amylose content when underwent irradiation at 25 and 50 kGy. Low amylose starches lost their pasting ability when irradiated at 25 and 50 kGy. Results from thermal behavior and pasting profile suggested that low level of cross-linking occurred in Hylon VII samples irradiated at 5 kGy. Severe reduction in pasting properties, gelatinization temperatures and relative crystallinity with increasing irradiation intensity revealed that waxy samples were affected more by gamma irradiation; this also indicated amylopectin was the starch fraction most affected by gamma irradiation. Alteration level was portrayed differently when different kind of physicochemical properties were investigated, in which the pasting properties and crystallinity of starches were more immensely influenced by gamma irradiation while thermal behavior was less affected. Despite the irradiation level, the morphology and crystal pattern of starch granules were found remain unchanged by irradiation. PMID:26396368

  4. Change in the enzymatic dual function of the peroxiredoxin protein by gamma irradiation

    NASA Astrophysics Data System (ADS)

    An, Byung Chull; Lee, Seung Sik; Lee, Jae Taek; Park, Chul-Hong; Lee, Sang Yeol; Chung, Byung Yeoup

    2012-08-01

    PP1084 protein was exposed to gamma irradiation ranging from 5 to 500 kGy. Native PAGE showed minor structural changes in PP1084 at 5 kGy, and major structural changes at >15 kGy. Size-exclusion chromatography (SEC) showed the formation of a new shoulder peak when the protein was irradiated with 15 and 30 kGy, and a double peak appeared at 100 kGy. The results of PAGE and SEC imply that PP1084 protein is degraded by gamma irradiation, with simultaneous oligomerization. PP1084 chaperone activity reached the highest level at 30 kGy of gamma irradiation, and then, decreased in a dose-dependent manner with increasing gamma irradiation. However, the peroxidase activity significantly decreased following exposure to all intensities of gamma irradiation. The improvement of chaperone activity using gamma irradiation might be promoted by the oligomeric structures containing covalently cross-linked amino acids. Consequently, PP1084 modification using gamma irradiation could elevate chaperone activity by about 3-4 folds compared to the non-irradiated protein.

  5. Comparison of structural properties of pristine and gamma irradiated single-wall carbon nanotubes: Effects of medium and irradiation dose

    SciTech Connect

    Kleut, D.; Jovanovic, S.; Markovic, Z.; Kepic, D.; Tosic, D.; Romcevic, N.; Marinovic-Cincovic, M.; Dramicanin, M.; Holclajtner-Antunovic, I.; Pavlovic, V.; Drazic, G.; Milosavljevic, M.; Todorovic Markovic, B.

    2012-10-15

    A systematic study of the gamma irradiation effects on single wall carbon nanotube (SWCNT) structure was conducted. Nanotubes were exposed to different doses of gamma irradiation in three media. Irradiation was carried out in air, water and aqueous ammonia. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and Raman spectroscopy confirmed the changes in the SWCNT structure. TGA measurements showed the highest percentage of introduced groups for the SWCNTs irradiated with 100 kGy. FTIR spectroscopy provided evidence for the attachment of hydroxyl, carboxyl and nitrile functional groups to the SWCNT sidewalls. Those groups were confirmed by EA. All irradiated SWCNTs had hydroxyl and carboxyl groups irrelevant to media used for irradiation, but nitrile functional groups were only identified in SWCNTs irradiated in aqueous ammonia. Raman spectroscopy indicated that the degree of disorder in the carbon nanotube structure correlates with the irradiation dose. For the nanotubes irradiated with the dose of 100 kGy, the Raman I{sub D}/I{sub G} ratio was three times higher than for the pristine ones. Atomic force microscopy showed a 50% decrease in nanotube length at a radiation dose of 100 kGy. Scanning and transmission electron microscopies showed significant changes in the morphology and structure of gamma irradiated SWCNTs. - Highlights: Black-Right-Pointing-Pointer Gamma irradiation causes SWCNT covalent functionalization. Black-Right-Pointing-Pointer Type of covalently attached groups to SWCNT surface depends on irradiation medium. Black-Right-Pointing-Pointer The SWCNT shortening level increases with applied irradiation dose. Black-Right-Pointing-Pointer The average length of carbon nanotubes decreased by 50% at the highest dose. Black-Right-Pointing-Pointer The diameter of SWCNT bundles becomes small as irradiation dose rises.

  6. Mechanical properties of acellular mouse lungs after sterilization by gamma irradiation.

    PubMed

    Uriarte, Juan J; Nonaka, Paula N; Campillo, Noelia; Palma, Renata K; Melo, Esther; de Oliveira, Luis V F; Navajas, Daniel; Farré, Ramon

    2014-12-01

    Lung bioengineering using decellularized organ scaffolds is a potential alternative for lung transplantation. Clinical application will require donor scaffold sterilization. As gamma-irradiation is a conventional method for sterilizing tissue preparations for clinical application, the aim of this study was to evaluate the effects of lung scaffold sterilization by gamma irradiation on the mechanical properties of the acellular lung when subjected to the artificial ventilation maneuvers typical within bioreactors. Twenty-six mouse lungs were decellularized by a sodium dodecyl sulfate detergent protocol. Eight lungs were used as controls and 18 of them were submitted to a 31kGy gamma irradiation sterilization process (9 kept frozen in dry ice and 9 at room temperature). Mechanical properties of acellular lungs were measured before and after irradiation. Lung resistance (RL) and elastance (EL) were computed by linear regression fitting of recorded signals during mechanical ventilation (tracheal pressure, flow and volume). Static (Est) and dynamic (Edyn) elastances were obtained by the end-inspiratory occlusion method. After irradiation lungs presented higher values of resistance and elastance than before irradiation: RL increased by 41.1% (room temperature irradiation) and 32.8% (frozen irradiation) and EL increased by 41.8% (room temperature irradiation) and 31.8% (frozen irradiation). Similar increases were induced by irradiation in Est and Edyn. Scanning electron microscopy showed slight structural changes after irradiation, particularly those kept frozen. Sterilization by gamma irradiation at a conventional dose to ensure sterilization modifies acellular lung mechanics, with potential implications for lung bioengineering. PMID:25241281

  7. Inactivation of fungal contaminants on Korean traditional cashbox by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Choi, Jong-il; Lim, Sangyong

    2016-01-01

    In this study, gamma irradiation was applied to decontaminate a Korean cultural artifact, a wooden cashbox stored in local museum. Fungi isolated from the wooden cashbox were identified by 18S rDNA sequencing methods. It was observed that the isolated fungi exhibited high similarity to Aspergillus niger, Penicillium verruculosum, and Trichoderma viride. Each strain was tested for sensitivity to gamma irradiation, and was inactivated by the irradiation at a dose of 5 kGy. The wooden cashbox was thus gamma-irradiated at this dose (5 kGy), and consequently decontaminated. Two months after the irradiation, when the wooden cashbox was retested to detect biological contamination, no fungi were found. Therefore, these results suggest that gamma irradiation at a low dose of 5 kGy can be applied for successful decontamination of wooden artifacts.

  8. Effect of gamma irradiation on the conversion of ginsenoside Rb1 to Rg3

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hun; Kwon, Sun-Kyu; Sung, Nak-Yun; Jung, Pil-Mun; Choi, Jong-il; Kim, Jae-Kyung; Sharma, Arun K.; Lee, Ju-Woon

    2012-08-01

    Ginsenosides, the most important secondary metabolites in ginseng, have various biological activities. Many studies have focused on the conversion of one of the major ginsenosides, Rb1, to the more active minor ginsenoside, Rg3. This study was carried out to investigate the effect of gamma irradiation on the conversion of Rb1 to Rg3. Rb1 solutions were gamma-irradiated at doses of 10 and 30 kGy and analyzed by high performance liquid chromatography (HPLC). HPLC chromatograms showed a decreased content of Rb1 with increasing irradiation dose, but the content of Rg3 was increased. The highest content of Rg3 was present in the 30 kGy-irradiated Rb1 sample. The cytotoxic effects tested in cancer cell lines were increased in the gamma-irradiated group. Therefore, these results suggest that gamma irradiation can be an effective method for the conversion of the ginsenoside Rb1 to Rg3.

  9. Gamma-Irradiated Sterile Cornea for Use in Corneal Transplants in a Rabbit Model

    PubMed Central

    Yoshida, Junko; Heflin, Thomas; Zambrano, Andrea; Pan, Qing; Meng, Huan; Wang, Jiangxia; Stark, Walter J.; Daoud, Yassine J.

    2015-01-01

    Purpose: Gamma irradiated corneas in which the donor keratocytes and endothelial cells are eliminated are effective as corneal lamellar and glaucoma patch grafts. In addition, gamma irradiation causes collagen cross inking, which stiffens collagen fibrils. This study evaluated gamma irradiated corneas for use in corneal transplantations in a rabbit model comparing graft clarity, corneal neovascularization, and edema. Methods: Penetrating keratoplasty was performed on rabbits using four types of corneal grafts: Fresh cornea with endothelium, gamma irradiated cornea, cryopreserved cornea, and fresh cornea without endothelium. Slit lamp examination was performed at postoperative week (POW) one, two, and four. Corneal clarity, edema, and vascularization were graded. Confocal microscopy and histopathological evaluation were performed. A P < 0.05 was statistically significant. Results: For all postoperative examinations, the corneal clarity and edema were statistically significantly better in eyes that received fresh cornea with endothelium compared to the other three groups (P < 0.05). At POW 1, gamma irradiated cornea scored better than the cryopreserved and fresh cornea without endothelium groups in clarity (0.9 vs. 1.5 and 2.6, respectively), and edema (0.6 vs. 0.8 and 2.0, respectively). The gamma irradiated corneas, cryopreserved corneas and the fresh corneas without endothelium, developed haze and edema after POW 2. Gamma irradiated cornea remained statistically significantly clearer than cryopreserved and fresh cornea without endothelium during the observation period (P < 0.05). Histopathology indicated an absence of keratocytes in gamma irradiated cornea. Conclusion: Gamma irradiated corneas remained clearer and thinner than the cryopreserved cornea and fresh cornea without endothelium. However, this outcome is transient. Gamma irradiated corneas are useful for lamellar and patch grafts, but cannot be used for penetrating keratoplasty. PMID:26180475

  10. The gamma irradiation effects on structural and optical properties of silk fibroin/HPMC blend films

    NASA Astrophysics Data System (ADS)

    Shetty, G. Rajesha; Rao, B. Lakshmeesha; Gowda, Mahadeva; Shivananda, C. S.; Asha, S.; Byrappa, K.; Sangappa, Y.

    2016-05-01

    In this paper the structural, chemical and optical properties of gamma irradiated silk fibroin/Hydroxypropyl methyl cellulose (SF-HPMC) blend films were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-visible spectroscopy. The results indicate that the gamma radiation did not affect significantly the primary structure of polypeptide arrangement in the blend films. But the optical properties of the blends changed with gamma irradiation dosage.

  11. Electrical Characteristics of Mid-wavelength HgCdTe Photovoltaic Detectors Exposed to Gamma Irradiation

    NASA Astrophysics Data System (ADS)

    Qiao, H.; Hu, W. D.; Li, T.; Li, X. Y.; Chang, Y.

    2016-09-01

    The study of electrical characteristics of mid-wavelength HgCdTe photodiodes irradiated by steady-state gamma rays has been carried out. The measurement of the current-voltage curves during irradiation revealed an abnormal variation of zero biased resistance R 0, and it didn't tend to change monotonically as observed in the case of post irradiation measurement. The irradiation effect was dominated by bulk effect inferred from the fitting calculations, and the generation-recombination current in the depletion region was drastically affected by gamma irradiation. Another irradiation effect was the linear increase of the series resistance with irradiation dosage which was related with the change of transportation parameters of carriers. The influence of hydrogenation on the gamma irradiation effects was also studied for comparison with the same batch of HgCdTe photodiodes, and it was found that R 0 for the hydrogenated devices showed similar change to those without hydrogenation. The series resistance, however, gave a totally different irradiation effect from the non-hydrogenated detectors and showed little change up to nearly 1 Mrad(Si) of gamma irradiation, which may be explained by the annihilation of hydrogen radicals with the defects caused by gamma irradiation.

  12. The influence of low temperature on gamma-ray irradiated permanent magnets.

    PubMed

    Han, Young Chul; Cha, Hyun Gil; Kim, Chang Woo; Ji, Eun Sun; Kim, Young Hwan; Kang, Dong In; Kang, Young Soo

    2009-12-01

    The temperature effect on the magnetic property of gamma-ray irradiated Nd-Fe-B and Sr-Ferrite magnets has been investigated. When the permanent magnets are exposed to gamma-ray, it's magnetic and other related properties are declined with degree of dose. The decreased magnetic property by gamma-ray irradiation at low temperature is similar with the result of magnet at high temperature. The temperature effect on the gamma-ray irradiation at exposed moment is also regarded as one of the important parameters for the reduced magnetic properties. The gamma-irradiation at low temperature was carried out at 195 K, and the changed properties of two kinds of magnets before and after gamma-irradiation were comparatively studied. The increased demagnetization of the magnets were studied by Hall probe. And changed Curie temperature and micro-crystal structure of each permanent magnet by gamma-ray irradiation has been also studied. Moreover the strong and broad single line shape of ESR signal in the resonance magnetic field is attributed to unpaired electron of Fe2+ in the sample by the effect of gamma-ray irradiation.

  13. Effect of gamma irradiation on structural and biological properties of a PLGA-PEG-hydroxyapatite composite.

    PubMed

    Shahabi, Sima; Najafi, Farhood; Majdabadi, Abbas; Hooshmand, Tabassom; Haghbin Nazarpak, Masoumeh; Karimi, Batool; Fatemi, Seyyed Mostafa

    2014-01-01

    Gamma irradiation is able to affect various structural and biological properties of biomaterials In this study, a composite of Hap/PLGA-PEG and their ingredients were submitted to gamma irradiation doses of 25 and 50 KGy. Various properties such as molecular weight (GPC), thermal behavior (DSC), wettability (contact angle), cell viability (MTT assay), and alkaline phosphatase activity were studied for the composites and each of their ingredients. The results showed a decrease in molecular weight of copolymer with no change in the glass transition and melting temperatures after gamma irradiation. In general gamma irradiation can increase the activation energy ΔH of the composites and their ingredients. While gamma irradiation had no effect on the wettability of copolymer samples, there was a significant decrease in contact angle of hydroxyapatite and composites with increase in gamma irradiation dose. This study showed an increase in biocompatibility of hydroxyapatite with gamma irradiation with no significant effect on cell viability in copolymer and composite samples. In spite of the fact that no change occurred in alkaline phosphatase activity of composite samples, results indicated a decrease in alkaline phosphatase activity in irradiated hydroxyapatites. These effects on the properties of PLGA-PEG-hydroxyapatite can enhance the composite application as a biomaterial. PMID:25574485

  14. Effect of Gamma Irradiation on Structural and Biological Properties of a PLGA-PEG-Hydroxyapatite Composite

    PubMed Central

    Shahabi, Sima; Najafi, Farhood; Majdabadi, Abbas; Hooshmand, Tabassom; Haghbin Nazarpak, Masoumeh; Karimi, Batool

    2014-01-01

    Gamma irradiation is able to affect various structural and biological properties of biomaterials In this study, a composite of Hap/PLGA-PEG and their ingredients were submitted to gamma irradiation doses of 25 and 50 KGy. Various properties such as molecular weight (GPC), thermal behavior (DSC), wettability (contact angle), cell viability (MTT assay), and alkaline phosphatase activity were studied for the composites and each of their ingredients. The results showed a decrease in molecular weight of copolymer with no change in the glass transition and melting temperatures after gamma irradiation. In general gamma irradiation can increase the activation energy ΔH of the composites and their ingredients. While gamma irradiation had no effect on the wettability of copolymer samples, there was a significant decrease in contact angle of hydroxyapatite and composites with increase in gamma irradiation dose. This study showed an increase in biocompatibility of hydroxyapatite with gamma irradiation with no significant effect on cell viability in copolymer and composite samples. In spite of the fact that no change occurred in alkaline phosphatase activity of composite samples, results indicated a decrease in alkaline phosphatase activity in irradiated hydroxyapatites. These effects on the properties of PLGA-PEG-hydroxyapatite can enhance the composite application as a biomaterial. PMID:25574485

  15. Increasing genetic variability in black oats using gamma irradiation.

    PubMed

    Silveira, G; Moliterno, E; Ribeiro, G; Costa, P M A; Woyann, L G; Tessmann, E W; Oliveira, A C; Cruz, C D

    2014-12-04

    The black oat (Avena strigosa Schreb) is commonly used for forage, soil cover, and green manure. Despite its importance, little improvement has been made to this species, leading to high levels of genotypic disuniformity within commercial cultivars. The objective of this study was to evaluate the efficiency of different doses of gamma rays [(60)Co] applied to black oat seeds on the increase of genetic variability of agronomic traits. We applied doses of 0, 10, 50, 100, and 200 Gy to the genotype ALPHA 94087 through exposure to [(60)Co]. Two experiments were conducted in the winter of 2008. The first aimed to test forage trait measurements such as plant height, dry matter yield, number of surviving tillers, and seedling stand. The second test assessed seed traits, such as yield and dormancy levels. Gamma irradiation seems not to increase seed yield in black oats, but it was effective in generating variability for the other traits. Tiller number and plant height are important selection traits to increase dry matter yield. Selection in advanced generations of mutant populations can increase the probability of identifying superior genotypes.

  16. Gamma-ray spectroscopy on irradiated MTR fuel elements

    NASA Astrophysics Data System (ADS)

    Terremoto, L. A. A.; Zeituni, C. A.; Perrotta, J. A.; da Silva, J. E. R.

    2000-08-01

    The availability of burnup data is an important requirement in any systematic approach to the enhancement of safety, economics and performance of a nuclear research reactor. This work presents the theory and experimental techniques applied to determine, by means of nondestructive gamma-ray spectroscopy, the burnup of Material Testing Reactor (MTR) fuel elements irradiated in the IEA-R1 research reactor. Burnup measurements, based on analysis of spectra that result from collimation and detection of gamma-rays emitted in the decay of radioactive fission products, were performed at the reactor pool area. The measuring system consists of a high-purity germanium (HPGe) detector together with suitable fast electronics and an on-line microcomputer data acquisition module. In order to achieve absolute burnup values, the detection set (collimator tube+HPGe detector) was previously calibrated in efficiency. The obtained burnup values are compared with ones provided by reactor physics calculations, for three kinds of MTR fuel elements with different cooling times, initial enrichment grades and total number of fuel plates. Both values show good agreement within the experimental error limits.

  17. Electron spin resonance study of. gamma. -irradiated nylon 6

    SciTech Connect

    Takigami, S.; Matsumoto, I.; Nakamura, Y.

    1981-12-01

    The free radicals trapped in oriented nylon 6 filaments after ..gamma..-irradiation under vacuum at room temperature were studied by ESR spectroscopy. The ESR spectrum measured after irradiation gradually changed to a broad singlet spectrum with decrease in the intensity. The ESR spectrum consisted of radicals with different orientation effects with respect to the outer magnetic field, and saturation effects in reference to microwave power. The simulation of the ESR spectrum from a Gaussian function gave a better fit to the observed spectrum than the calculation from a Lorentzian function. From the resolution of the spectrum from a Gaussian function, the observed spectrum is generated from three kinds of radicals. The relative radical concentration for the first, second, and third radical is about 75%, 6%, and 19% of the total radical concentration, respectively. With regard to the stability of the radicals, the third radical shows a comparatively long lifetime. The first and second radicals show almost identical lifetime, and their concentrations reduce to about 40% of the initial value during the 2 days at room temperature.

  18. Gamma irradiation inhibits wound induced browning in shredded cabbage.

    PubMed

    Banerjee, Aparajita; Suprasanna, Penna; Variyar, Prasad S; Sharma, Arun

    2015-04-15

    Gamma-radiation induced browning inhibition in minimally processed shredded cabbage stored (10 °C) for up to 8 days was investigated. γ-irradiation (2 kGy) resulted in inhibition of browning as a result of down-regulation (1.4-fold) in phenylalanine ammonia lyase (PAL) gene expression and a consequent decrease in phenylalanine ammonia lyase (PAL) activity. Activity of polyphenol oxidase and peroxidase, total and individual phenolic content as well as o-quinone concentration were, however, unaffected. In the non-irradiated samples, PAL activity increased as a consequence of up-regulation of PAL gene expression after 24 and 48 h by 1.2 and 7.7-fold, respectively, during storage that could be linearly correlated with enhanced quinone formation and browning. Browning inhibition in radiation processed shredded cabbage as a result of inhibition of PAL activity was thus clearly demonstrated. The present work provides an insight for the first time on the mechanism of browning inhibition at both biochemical and genetic level.

  19. Online monitoring of gamma irradiated perfluorinated polymer optical fiber

    NASA Astrophysics Data System (ADS)

    Sporea, Dan; Mihai, Laura; Neguţ, Daniel; Stajanca, Pavol; Krebber, Katerina

    2016-04-01

    In this paper, we present the first results regarding the on-line monitoring of gamma-ray exposure effects on a commercial multi-mode perfluorinated polymer optical fiber (PF-POF), type GigaPOF-50SR from Chromis Fiberoptics. Our focus was to evaluate on-line the radiation induced attenuation (RIA) over a wide spectral range (320 nm - 1700 nm), in order to assess the fiber's radiation hardness and its possible use in radiation detection. An Ocean Optics QE65000 high sensitivity spectrometer and a StellarNet near-IR spectrometer were used to cover the spectral ranges 200 nm - 1μm and 900 nm - 1.6 μm, respectively. Electron paramagnetic resonance was used to monitor the recovery of the irradiation induced centers at room temperature. The study indicated that the optical fiber can be used as radiation monitor at low dose rates by measuring the attenuation in the UV, while higher dose rates irradiation can be observed by RIA monitoring at specific wavelengths in the visible spectral range.

  20. Bystander responses in low dose irradiated cells treated with plasma from gamma irradiated blood

    NASA Astrophysics Data System (ADS)

    Acheva, A.; Georgieva, R.; Rupova, I.; Boteva, R.; Lyng, F.

    2008-02-01

    There are two specific low-dose radiation-induced responses that have been the focus of radiobiologists' interest in recent years. These are the bystander effect in non-irradiated cells and the adaptive response to a challenge dose after prior low dose irradiation. In the present study we have investigated if plasma from irradiated blood can act as a 'challenge dose' on low dose irradiated reporter epithelial cells (HaCaT cell line). The main aim was to evaluate the overall effect of low dose irradiation (0.05 Gy) of reporter cells and the influence of bystander factors in plasma from 0.5 Gy gamma irradiated blood on these cells. The effects were estimated by clonogenic survival of the reporter cells. We also investigated the involvement of reactive oxygen species (ROS) as potential factors involved in the bystander signaling. Calcium fluxes and mitochondrial membrane potential (MMP) depolarization were also examined as a marker for initiation of apoptosis in the reporter cells. The results show that there are large individual differences in the production of bystander effects and adaptive responses between different donors. These may be due to the specific composition of the donor plasma. The observed effects generally could be divided into two groups: adaptive responses and additive effects. ROS appeared to be involved in the responses of the low dose pretreated reporter cells. In all cases there was a significant decrease in MMP which may be an early event in the apoptotic process. Calcium signaling also appeared to be involved in triggering apoptosis in the low dose pretreated reporter cells. The heterogeneity of the bystander responses makes them difficult to be modulated for medical uses. Specific plasma characteristics that cause these large differences in the responses would need to be identified to make them useful for radiotherapy.

  1. gamma. Irradiation induced formation of PCB-solvent adducts in aliphatic solvents

    SciTech Connect

    Lepine, F.; Milot, S.; Gagne, N. )

    1990-09-01

    {gamma}Irradiation induced formation of PCB-solvent adducts was investigated as a model for PCB residues in irradiated food. Formation of cyclohexyl adducts of PCBs was found to be significant when pure PCB congeners and Aroclor mixture were irradiated in cyclohexane and cyclohexene. Reaction pathways were investigated, and the effects of oxygen and electron scavenger were studied.

  2. Imaging of gamma-Irradiated Regions of a Crystal

    NASA Technical Reports Server (NTRS)

    Dragoi, Danut; McClure, Steven; Johnston, Allan; Chao, Tien-Hsin

    2004-01-01

    A holographic technique has been devised for generating a visible display of the effect of exposure of a photorefractive crystal to gamma rays. The technique exploits the space charge that results from trapping of electrons in defects induced by gamma rays. The technique involves a three-stage process. In the first stage, one writes a holographic pattern in the crystal by use of the apparatus shown in Figure 1. A laser beam of 532-nm wavelength is collimated and split into signal and reference beams by use of a polarizing beam splitter. On its way to the crystal, the reference beam goes through a two-dimensional optical scanner that contains two pairs of lenses (L1y, L2y and L1x,L2x) and mirrors M1 and M2, which can be rotated by use of micrometer drives to make fine adjustments. The signal beam is sent through a spatial light modulator that imposes the holographic pattern, then through two imaging lenses L(sub img) on its way to the crystal. An aperture is placed at the common focus of lenses Limg to suppress high-order diffraction from the spatial light modulator. The hologram is formed by interference between the signal and reference beams. A camera lens focuses an image of the interior of the crystal onto a charge-coupled device (CCD). If the crystal is illuminated by only the reference beam once the hologram has been formed, then an image of the hologram is formed on the CCD: this phenomenon is exploited to make visible the pattern of gamma irradiation of the crystal, as described next. In the second stage of the process, the crystal is removed from the holographic apparatus and irradiated with rays at a dose of about 100 krad. In the third stage of the process, the crystal is remounted in the holographic apparatus in the same position as in the first stage and illuminated with only the reference beam to obtain the image of the hologram as modified by the effect of the rays. The orientations of M1 and M2 can be adjusted slightly, if necessary, to maximize the

  3. Gamma irradiation increases the antioxidant properties of Tualang honey stored under different conditions.

    PubMed

    Khalil, Md Ibrahim; Sulaiman, Siti Amrah; Alam, Nadia; Moniruzzaman, Mohammed; Bai'e, Saringat; Man, Che Nin; Jamalullail, Syed Mohsin Sahil; Gan, Siew Hua

    2012-01-11

    This study was conducted to evaluate the effects of evaporation, gamma irradiation and temperature on the total polyphenols, flavonoids and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities of Tualang honey samples (n = 14) following storage over three, six or twelve months. The mean polyphenol concentrations of the six gamma irradiated honey samples at three, six and twelve months, respectively, were 96.13%, 98.01% and 102.03% higher than the corresponding values of the eight non-gamma irradiated samples. Similarly, the mean values for flavonoids at three, six and twelve months were 111.52%, 114.81% and 110.04% higher, respectively, for the gamma irradiated samples. The mean values for DPPH radical-scavenging activities at three, six and twelve months were also 67.09%, 65.26% and 44.65% higher, respectively, for the gamma irradiated samples. These data indicate that all gamma irradiated honey samples had higher antioxidant potential following gamma irradiation, while evaporation and temperature had minor effects on antioxidant potential.

  4. Influence of gamma-irradiation and microwaves on the antioxidant property of some essential oils.

    PubMed

    Farag, R S; el-Khawas, K H

    1998-03-01

    The antioxidant property of anise, caraway, cumin and fennel essential oils extracted from untreated, gamma-irradiated and microwaved fruits against sunflower oil oxidative rancidity was evaluated. The fruits were exposed to gamma-irradiation at 10 KGy and to microwaves at low oven power setting for 1 min. The essential oils were added individually (200 ppm) to sunflower oil and the rate of oil oxidation was followed by determining the peroxide value during storage at room temperature. The irradiated and microwaved essential oils exhibited an antioxidant activity and was superior to that of sunflower oil catalysed by a mixture of BHT + BHA (200 ppm) in most cases. The present data show that gamma-irradiation and microwave treatments did not affect the antioxidant property of the essential oils under study. In addition the essential oils extracted from the gamma-irradiated fruits were more effective as an antioxidant in sunflower oil than those produced from microwaved fruits.

  5. Effect of gamma irradiation on the microstructure and post-mortem anaerobic metabolism of bovine muscle

    NASA Astrophysics Data System (ADS)

    Yook, Hong.-Sun; Lee, Ju.-Woon; Lee, Kyong.-Haeng; Kim, Moo.-Kang; Song, Chi.-won; Byun, Myung.-Woo

    2001-05-01

    Experiments were performed to study the effect of gamma irradiation on morphological properties and post-mortem metabolism in bovine M. sternomandibularis with special reference to ultrastructure, shear force, pH and ATP breakdown. The shortening of sarcomere was not observed in gamma-irradiated muscle, however, the disappearance of M-line and of A- and I-bands was perceptible. During cold storage, the destruction of muscle bundles was faster in the gamma-irradiated muscle than in the non-irradiated with a dose-dependent manner. The same is true for the post mortem pH drop and ATP breakdown. So, experimental results confirmed that the anaerobic metabolism and morphological properties are noticeably affected by gamma irradiation in beef.

  6. Effect of gamma-irradiation on the survival of Listeria monocytogenes and allergenicity of cherry tomatoes

    NASA Astrophysics Data System (ADS)

    Todoriki, Setsuko; Bari, Latiful; Kitta, Kazumi; Ohba, Mika; Ito, Yasuhiro; Tsujimoto, Yuka; Kanamori, Norihito; Yano, Erika; Moriyama, Tatsuya; Kawamura, Yukio; Kawamoto, Shinichi

    2009-07-01

    The presence of Listeria monocytogenes in fresh produce is a growing concern because of the possibility of food-borne illness. Ionizing radiation is an effective non-thermal means of eliminating pathogenic bacteria in fresh produce; however, the effect of ionizing irradiation on the allergenic properties of the host commodities remains unknown. This study aimed (i) to determine the effective dose of gamma-irradiation in eliminating L. monocytogenes on whole cherry tomatoes and (ii) to evaluate the effect of gamma-irradiation on the allergenic properties of tomato proteins. Cherry tomatoes that were inoculated with a mixture of five L. monocytogenes strains were treated with gamma-rays from a 60Co source. A 1.25 kGy dose of gamma-irradiation was found to be sufficient to eliminate L. monocytogenes on whole cherry tomatoes. The immunoblot profile of serum samples obtained from two patients with tomato allergy revealed that gamma-irradiation did not affect the allergenicity of tomato proteins for up to 7 days after irradiation when the tomatoes were stored at 20 °C. Additionally, the m-RNA levels of β-fructofuranosidase, polygalacturonase, pectin esterase, and superoxide dismutase, the main allergenic proteins in tomato, were not affected by the applied irradiation dose. Thus, this study demonstrated that a 1.25 kGy dose of gamma-irradiation effectively eliminates L. monocytogenes on cherry tomatoes without affecting the expression of allergenic proteins in the fruits.

  7. Improvement of color and physiological properties of tuna-processing by-product by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Choi, Jong-il; Kim, Hyun-Joo; Kim, Jae-Hun; Song, Beom-Seok; Chun, Byeong-Soo; Ahn, Dong-Hyun; Byun, Myung-Woo; Lee, Ju-Woon

    2009-07-01

    Although the by-products from fishery industry had many nutrients, it is being wasted or only used as bacteria media. In this study, the effect of a gamma irradiation on the cooking drips of Thunnus thynnus (CDT) was investigated to examine the possible use of the cooking drips as a functional material for food and cosmetic composition. Total aerobic bacteria, and yeasts/molds from CDT were detected at the level of 2.79 and 2.58 Log CFU/mL, respectively. But, CDT was efficiently sterilized by a gamma irradiation at a low dose of 1 kGy. The Hunter L* value of the gamma-irradiated ethanol extract of CDT was increased, and the a* and b* values were decreased compared to the non-irradiated extract, showing color improvement. Antioxidant activity of the ethanol extract of CDT was increased by a gamma irradiation depending on the irradiation dose. The increased contents of polyphenolic compounds and proteins in CDT extract by gamma irradiation may be the reason of the increased biological activity. These results suggested that the wasted cooking drips can be successfully used as functional components with gamma irradiation treatment.

  8. Gamma irradiation improves the antioxidant activity of Aloe vera (Aloe barbadensis miller) extracts

    NASA Astrophysics Data System (ADS)

    Mi Lee, Eun; Bai, Hyoung-Woo; Sik Lee, Seung; Hyun Hong, Sung; Cho, Jae-Young; Yeoup Chung, Byung

    2012-08-01

    Aloe has been widely used in food products, pharmaceuticals, and cosmetics because of its aromatic and therapeutic properties. In the present study, the ethanolic extracts of aloe gel were gamma-irradiated from 10 to 100 kGy. After gamma irradiation, the color of the ethanolic extracts of aloe gel changed to red; this color persisted up to 40 kGy but disappeared above 50 kGy. Liquid chromatography/mass spectrometry analysis demonstrated the production of a new, unknown compound (m/z=132) after gamma irradiation of the ethanolic extracts of aloe gel. The amount of this unknown compound increased with increasing irradiation up to 80 kGy, and it was degraded at 100 kGy. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by the 1,1-diphenyl-2-picrylhydrazyl-radical scavenging capacity. The antioxidant activity of aloe extract was dramatically increased from 53.9% in the non-irradiated sample to 92.8% in the sample irradiated at 40 kGy. This strong antioxidant activity was retained even at 100 kGy. These results indicate that gamma irradiation of aloe extract can enhance its antioxidant activity through the formation of a new compound. Based on these results, increased antioxidant activity of aloe extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  9. Effect of gamma irradiation on the physicochemical properties of alkali-extracted rice starch

    NASA Astrophysics Data System (ADS)

    Ashwar, Bilal Ahmad; Shah, Asima; Gani, Asir; Rather, Sajad Ahmad; Wani, Sajad Mohd.; Wani, Idrees Ahmed; Masoodi, Farooq Ahmad; Gani, Adil

    2014-06-01

    Starches isolated from two newly released rice varieties (K-322 and K-448) were subject to irradiation at 0, 5, 10, and 20 kGy doses. Comparative study between native (not irradiated) and irradiated starch samples was carried out to evaluate the changes in physicochemical, morphological and pasting properties due to gamma irradiation. Significant decrease was found in apparent amylose content, pH, swelling power, syneresis, and pasting properties, whereas carboxyl content, water absorption capacity, and transmittance were found to increase with the increase in irradiation dose. Granule morphology of native and irradiated starches under scanning electron microscope revealed that granules were polygonal or irregular in shape. The starch granules were somewhat deformed by gamma irradiation. X-ray diffraction pattern showed A type of pattern in native as well as irradiated starches.

  10. Effect of gamma irradiation on DC electrical conductivity of ZnO nanoparticles

    SciTech Connect

    Swaroop, K.; Somashekarappa, H. M.; Naveen, C. S.; Jayanna, H. S.

    2015-06-24

    The temperature dependent dc electrical conductivity of gamma irradiated Zinc oxide (ZnO) nanoparticles is presented in this paper. The X-ray diffraction (XRD) pattern shows hexagonal wurtzite structure of ZnO. Fourier Transform Infrared Spectroscopy (FTIR) confirms Zn-O stretching vibrations. UV-Visible spectroscopy studies show that the energy band gap (E{sub g}) of the prepared ZnO nanoparticles increases with respect to gamma irradiation dose, which can be related to room temperature dc electrical conductivity. The result shows significant variation in the high temperature dc electrical conductivity of ZnO nanoparticles due to gamma irradiation.

  11. Effect of gamma irradiation on curcuminoids and volatile oils of fresh turmeric ( Curcuma longa)

    NASA Astrophysics Data System (ADS)

    Dhanya, R.; Mishra, B. B.; Khaleel, K. M.

    2011-11-01

    In our earlier study a radiation dose of 5 kGy was reported to be suitable for microbial decontamination and shelf life extension of fresh turmeric ( Curcuma longa), while maintaining its quality attributes. In continuation of that work, the effect of gamma radiation on curcuminoids and volatile oil constituents in fresh turmeric was studied. Fresh peeled turmeric rhizomes were gamma irradiated at doses of 1, 3 and 5 kGy. Curcuminoid content and volatile oils were analyzed by reverse phase HPLC and GC-MS, respectively. The curcuminoid content was slightly increased by gamma irradiation. No statistically significant changes were observed due to irradiation in majority of the volatile oil constituents.

  12. Apoptosis of murine BW 5147 thymoma cells induced by dexamethasone and gamma-irradiation.

    PubMed

    Kruman, I I; Matylevich, N P; Beletsky, I P; Afanasyev, V N; Umansky, S R

    1991-08-01

    The mode and the kinetics of the death of T-thymoma cells upon dexamethasone treatment and gamma-irradiation (10Gy) have been studied using flow cytometry and biochemical analysis. It has been shown that the hormone and gamma-irradiation induce cell death by apoptosis. In both cases the cells are initially blocked in G2/M and die only after overcoming the blockage and cytokinesis. A short exposure to dexamethasone results in a cytostatic effect, whereas a cytotoxic effect is absent. Reducing serum concentration to 2% causes more rapid death both following gamma-irradiation and dexamethasone. These results are discussed in relation to cell death and proliferation.

  13. Effect of gamma irradiation on high temperature hardness of low-density polyethylene

    NASA Astrophysics Data System (ADS)

    Chen, Pei-Yun; Yang, Fuqian; Lee, Sanboh

    2015-11-01

    Gamma irradiation can cause the change of microstructure and molecular structure of polymer, resulting in the change of mechanical properties of polymers. Using the hardness measurement, the effect of gamma irradiation on the high temperature hardness of low-density polyethylene (LDPE) was investigated. The gamma irradiation caused the increase in the melting point, the enthalpy of fusion, and the portion of crystallinity of LDPE. The Vickers hardness of the irradiated LDPE increases with increasing the irradiation dose, annealing temperature, and annealing time. The activation energy for the rate process controlling the reaction between defects linearly decreases with the irradiation dose. The process controlling the hardness evolution in LDPE is endothermic because LDPE is semi-crystalline.

  14. Effect of gamma irradiation on viscosity reduction of cereal porridges for improving energy density

    NASA Astrophysics Data System (ADS)

    Lee, Ju-Woon; Kim, Jae-Hun; Oh, Sang-Hee; Byun, Eui-Hong; Yook, Hong-Sun; Kim, Mee-Ree; Kim, Kwan-Soo; Byun, Myung-Woo

    2008-03-01

    Cereal porridges have low energy and nutrient density because of its viscosity. The objective of the present study was to evaluate the effect of irradiation on the reduction of viscosity and on the increasing solid content of cereal porridge. Four cereals, wheat, rice, maize (the normal starchy type) and waxy rice, were used in this study. The porridge with 3000 cP was individually prepared from cereal flour, gamma-irradiated at 20 kGy and tested. Gamma irradiation of 20 kGy was allowed that the high viscous and rigid cereal porridges turned into semi-liquid consistencies. The solid contents of all porridges could increase by irradiation, compared with non-irradiated ones. No significant differences of starch digestibility were observed in all cereal porridge samples. The results indicated that gamma irradiation might be helpful for improving energy density of cereal porridge with acceptable consistency.

  15. Dyeing behaviour of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves (Lawsonia inermis)

    NASA Astrophysics Data System (ADS)

    Rehman, Fazal-ur; Adeel, Shahid; Qaiser, Summia; Ahmad Bhatti, Ijaz; Shahid, Muhammad; Zuber, Mohammad

    2012-11-01

    Dyeing behavior of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves has been investigated. Cotton and dye powder are irradiated to different absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. The dyeing parameters such as dyeing time, electrolyte (salt) concentration and mordant concentrations using copper and iron as mordants are optimized. Dyeing is performed using un-irradiated and irradiated cotton with dye solutions and their color strength values are evaluated in CIE Lab system using Spectraflash -SF650. Methods suggested by International Standard Organization (ISO) have been employed to investigate the colourfastness properties such as colourfastness to light, washing and rubbing of irradiated dyed fabric. It is found that gamma ray treatment of cotton dyed with extracts of henna leaves has significantly improved the color strength as well as enhanced the rating of fastness properties.

  16. Semiconductor quantum dot scintillation under gamma-ray irradiation

    SciTech Connect

    Letant, S E; Wang, T

    2006-08-23

    We recently demonstrated the ability of semiconductor quantum dots to convert alpha radiation into visible photons. In this letter, we report on the scintillation of quantum dots under gamma-ray irradiation, and compare the energy resolution of the 59 keV line of Americium 241 obtained with our quantum dot-glass nanocomposite material to that of a standard sodium iodide scintillator. A factor 2 improvement is demonstrated experimentally and interpreted theoretically using a combination of energy-loss and photon transport models. These results demonstrate the potential of quantum dots for room-temperature gamma-ray detection, which has applications in medical imaging, environmental monitoring, as well as security and defense. Present technology in gamma radiation detection suffers from flexibility and scalability issues. For example, bulk Germanium provides fine energy resolution (0.2% energy resolution at 1.33 MeV) but requires operation at liquid nitrogen temperature. On the other hand, Cadmium-Zinc-Telluride is a good room temperature detector ( 1% at 662 keV) but the size of the crystals that can be grown is limited to a few centimeters in each direction. Finally, the most commonly used scintillator, Sodium Iodide (NaI), can be grown as large crystals but suffers from a lack of energy resolution (7% energy resolution at 662 keV). Recent advancements in nanotechnology6-10 have provided the possibility of controlling materials synthesis at the molecular level. Both morphology and chemical composition can now be manipulated, leading to radically new material properties due to a combination of quantum confinement and surface to volume ratio effects. One of the main consequences of reducing the size of semiconductors down to nanometer dimensions is to increase the energy band gap, leading to visible luminescence, which suggests that these materials could be used as scintillators. The visible band gap of quantum dots would also ensure both efficient photon counting

  17. Control of Postharvest Bacterial Soft Rot by Gamma Irradiation and its Potential Modes of Action

    PubMed Central

    Jeong, Rae-Dong; Chu, Eun-Hee; Park, Duck Hwan; Park, Hae-Jun

    2016-01-01

    Gamma irradiation was evaluated for its in vitro and in vivo antibacterial activity against a postharvest bacterial pathogen, Erwinia carotovora subsp. carotovora (Ecc). Gamma irradiation in a bacteria cell suspension resulted in a dramatic reduction of the viable counts as well as an increase in the amounts of DNA and protein released from the cells. Gamma irradiation showed complete inactivation of Ecc, especially at a dose of 0.6 kGy. In addition, scanning electron microscopy of irradiated cells revealed severe damage on the surface of most bacterial cells. Along with the morphological changes of cells by gamma irradiation, it also affected the membrane integrity in a dose-dependent manner. The mechanisms by which the gamma irradiation decreased the bacterial soft rot can be directly associated with the disruption of the cell membrane of the bacterial pathogen, along with DNA fragmentation, results in dose-dependent cell inactivation. These findings suggest that gamma irradiation has potential as an antibacterial approach to reduce the severity of the soft rot of paprika. PMID:27147935

  18. Color changes in CR-39 nuclear track detector by gamma and laser irradiation

    NASA Astrophysics Data System (ADS)

    Nouh, S. A.; Said, A. F.; Atta, M. R.; El-Melleegy, W. M.; El-Meniawy, S.

    2006-07-01

    A study of the effect of gamma and laser irradiation on the color changes of polyallyl diglycol (CR-39) solid-state nuclear track detector was performed. CR-39 detector samples were classified into two main groups. The first group was irradiated with gamma doses at levels between 20 and 300 kGy, whereas the second group was exposed to infrared laser radiation with energy fluences at levels between 0.71 and 8.53 J/cm(2) . The transmission of these samples in the wavelength range 300-2500 nm, as well as any color changes, was studied. Using the transmission data, both the tristimulus and the coordinate values of the Commission Internationale de l'Eclairage (CIE) LAB were calculated. Also, the color differences between the non-irradiated samples and those irradiated with different gamma or laser doses were calculated. The results indicate that the CR-39 detector acquires color changes under gamma or laser irradiation, but it has more response to color changes by gamma irradiation. In addition, structural property studies using infrared spectroscopy were performed. The results indicate that the irradiation of a CR-39 detector with gamma or laser radiations causes the cleavage of the carbonate linkage that can be attributed to the H abstraction from the backbone of the polymer, associated with the formation of CO 2 and OH with varying intensities.

  19. Detection of gamma-irradiation effect on DNA and protein using magnetic sensor and cyclic voltammetry.

    PubMed

    Park, Duck-Gun; Song, Hoon; Kishore, M B; Vértesy, G; Lee, Duk-Hyun

    2013-11-01

    In this study, a magnetic sensor utilizing Planar Hall Resistance (PHR) and cyclic Voltammetry (CV) for detecting the radiation effect was fabricated. Specifically, we applied in parallel a PHR sensor and CV device to monitor the irradiation effect on DNA and protein respectively. Through parallel measurements, we demonstrated that the PHR sensor and CV are sensitive enough to measure irradiation effect. The PHR voltage decreased by magnetic nanobead labeled DNA was slightly recovered after gamma ray irradiation. The behavior of cdk inhibitor protein p21 having a sandwich structure of Au/protein G/Ab/Ag/Ab was checked by monitoring the cyclic Voltammetry signal in analyzing the gamma ray irradiation effect.

  20. Use of gamma irradiation to prevent aflatoxin B 1 production in smoked dried fish

    NASA Astrophysics Data System (ADS)

    Ogbadu, G. H.

    Smoked dried fish bought from the Nigerian market was inoculated with spores of barAspergillus flavus (U.I. 81) and irradiated with doses of 0.625, 1.25, 2.50 and 5.00 KGy gamma irradiation. The effect of aflatoxin B 1 production on subsequent incubation for 8 days as stationary cultures was measured. The amount of aflatoxin B 1 produced was found to decrease with increased gamma irradiation dose levels. While the non-irradiated control produced significantly (at 1% level) greater amounts of aflatoxin B 1 as compared to the treated cultures.

  1. Poly(lactide-co-glycolide) microspheres containing bupivacaine: comparison between gamma and beta irradiation effects.

    PubMed

    Montanari, L; Cilurzo, F; Selmin, F; Conti, B; Genta, I; Poletti, G; Orsini, F; Valvo, L

    2003-07-31

    The beta- and gamma-irradiation effects on stability of microspheres made of poly(lactide-co-glycolide) 50:50 copolymer (PLGA) containing bupivacaine (BU) were studied. Microspheres containing 10, 25, and 40% w/w, respectively, of BU were prepared by spray drying and irradiated in air with beta- and gamma-irradiation at a dose of 25 kGy. Morphology (atomic force microscopy, particle-size analysis), physico-chemical characteristics (DSC and FT-IR spectroscopy), drug content and in vitro dissolution profile of microspheres were all determined; the stability of irradiated microspheres was evaluated over a 9-month period. The decrease of BU content in gamma-irradiated microspheres was almost always constant independent of the amount of BU per sample, therefore it was in inverse proportion to drug loading (range between 5 and 15%). BU release rate increased immediately after irradiation and increased slightly until 90 days of storage. As far as beta-irradiated microspheres are concerned, BU content decreased in a significant way (approximately 3%) only in microspheres containing 10% w/w of BU. Immediately after irradiation, drug release rate in beta-irradiated microspheres increased less than in the corresponding gamma-irradiated microspheres, and it did not change further over the following storage period. BU-loaded microspheres have been shown to be more stable against beta- than gamma-irradiation. AFM revealed that the surface roughness of the irradiated microspheres increases depending on irradiation. As such, if a parameter is quantifiable, it is proposed as a marker of degradation due to ionizing radiation. PMID:12880695

  2. [Effect of gamma-linolenic acid on microsomal oxidation in the rat liver following gamma-irradiation].

    PubMed

    Zavodnik, L B; Sushko, L I; Tarasov, Iu A; Ignatenko, K V; Chumachenko, S S; Ovchinnikov, V A; Brzosko, V; Buko, V U

    2001-01-01

    The antioxidant and radioprotector properties of gamma-linolenic acid isolated from the seeds of Borago officialis were studied on rats gamma-irradiated to a dose of 1 Gy. The irradiation caused an increase in the content of malonaldehyde in microsomal liver fraction and disturbed the metabolism of xenobiotics. The administration of gamma-linolenic acid in the form of a commercial drug Neoglandin (daily dose, 150 mg/kg, p.o.; over 1, 3, or 7 days after irradiation reduced the level of lipid peroxidation (for all treatment schedules), normalized the activity of NADPH-oxidase, NADH-oxidase, and NADPH-reductase, and increased the content of cytochromes P-450 and b5 as compared to bothirradiated and control animals. PMID:11589114

  3. DECOMMISSIONING THE BROOKHAVEN NATIONAL LABORATORY BUILDING 830 GAMMA IRRADIATION FACILITY.

    SciTech Connect

    BOWERMAN, B.S.; SULLIVAN, P.T.

    2001-08-13

    The Building 830 Gamma Irradiation Facility (GIF) at Brookhaven National Laboratory (BNL) was decommissioned because its design was not in compliance with current hazardous tank standards and its cobalt-60 sources were approaching the end of their useful life. The facility contained 354 stainless steel encapsulated cobalt-60 sources in a pool, which provided shielding. Total cobalt-60 inventory amounted to 24,000 Curies when the sources were shipped for disposal. The decommissioning project included packaging, transport, and disposal of the sources and dismantling and disposing of all other equipment associated with the facility. Worker exposure was a major concern in planning for the packaging and disposal of the sources. These activities were planned carefully according to ALARA (As Low As Reasonably Achievable) principles. As a result, the actual occupational exposures experienced during the work were within the planned levels. Disposal of the pool water required addressing environmental concerns, since the planned method was to discharge the slightly contaminated water to the BNL sewage treatment plant. After the BNL evaluation procedure for discharge to the sewage treatment plant was revised and reviewed by regulators and BNL's Community Advisory Council, the pool water was discharged to the Building 830 sanitary system. Because the sources were sealed and the pool water contamination levels were low, most of the remaining equipment was not contaminated; therefore disposal was straightforward, as scrap metal and construction debris.

  4. Effect of gamma irradiation on Listeria monocytogenes in frozen, artificially contaminated sandwiches.

    PubMed

    Clardy, S; Foley, D M; Caporaso, F; Calicchia, M L; Prakash, A

    2002-11-01

    Gamma irradiation has been shown to effectively control L monocytogenes in uncooked meats but has not been extensively studied in ready-to-eat foods. The presence of Listeria in ready-to-eat foods is often due to postprocess contamination by organisms in the food-manufacturing environment. Because gamma irradiation is applied after products are packaged, the treated foods are protected from environmental recontamination. Currently, a petition to allow gamma irradiation of ready-to-eat foods is under review by the Food and Drug Administration. This study was conducted to determine if gamma irradiation could be used to control L. monocytogenes in ready-to-eat sandwiches. Ham and cheese sandwiches were contaminated with L. monocytogenes, frozen at -40 degrees C, and exposed to gamma irradiation. Following irradiation, sandwiches were assayed for L. monocytogenes. A triangle test was performed to determine if irradiated and nonirradiated sandwiches differed in sensory quality. We found that the D10-values ranged from 0.71 to 0.81 kGy and that a 5-log reduction would require irradiation with 3.5 to 4.0 kGy. The results of a 39-day storage study of sandwiches inoculated with 10(7) CFU of L monocytogenes per g indicated that counts for nonirradiated sandwiches remained fairly constant. Counts for sandwiches treated with 3.9 kGy decreased by 5 log units initially and then decreased further during storage at 4 degrees C. Sensory panelists could distinguish between irradiated and nonirradiated sandwiches but were divided on whether irradiation adversely affected sandwich quality. Our results suggest that manufacturers of ready-to-eat foods could use gamma irradiation to control L. monocytogenes and improve the safety of their products.

  5. Role of gamma irradiation on the natural antioxidants in cumin seeds

    NASA Astrophysics Data System (ADS)

    Kim, Jae Hun; Shin, Mee-Hye; Hwang, Young-Jeong; Srinivasan, Periasamy; Kim, Jae Kyung; Park, Hyun Jin; Byun, Myung Woo; Lee, Ju Woon

    2009-02-01

    Antioxidants quench oxidation by transferring hydrogen atoms to free radicals. In the present investigation, the effect of gamma irradiation on the natural antioxidants of irradiated cumin was studied. Cumin samples were purchased from retailers and then irradiated in a cobalt-60 irradiator to 0, 1, 3, 5 and 10 kGy at ambient temperature. The effect of irradiation on the antioxidant properties of the cumin seed were investigated by evaluating the radical-scavenging effect on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, determination of ferric reducing antioxidant power (FRAP), total polyphenol content (TPC) and the antioxidant index by β-carotene/linoleic acid co-oxidation. Electron spin resonance (ESR) was performed to assess ionization of cumin seeds by gamma irradiation. Irradiation was found to nonsignificantly increase and/or maintain all antioxidant parameters, TPC and the ESR signal intensity was found to be increased in cumin seeds.

  6. Effect of gamma irradiation on nutrient digestibility in SPF mini-pig

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Yeob; Cho, Sung-Back; Kim, Yoo-Yong; Ohh, Sang-Jip

    2011-01-01

    This study was carried out to evaluate the effect of gamma irradiation on nutrient digestibility of either soy-based or milk-based diet for specific pathogen-free (SPF) mini-pigs. Gamma irradiation of the diets was done at dosage of 10 kGy with 60Co whereas autoclaving was executed at 121 °C for 20 min. Apparent crude protein digestibilities of gamma irradiated diets were higher ( p<0.05) than those of autoclaved diets regardless of diet type. Digestibilities of dry matter, gross energy and total carbohydrate in the irradiated diet were higher than those of the autoclaved diet. From the results of nutrient digestibility of mini-pig diets in this study, 10 kGy gamma radiation was suggested as a convenient diet radicidation method that can minimize the decrease in nutrient digestibility on feeding to SPF mini-pigs.

  7. Effect of gamma irradiation on HPMC/ZnO nanocomposite films

    SciTech Connect

    Rao, B. Lakshmeesha; Asha, S.; Madhukumar, R.; Latha, S.; Gowda, Mahadeva; Shivananda, C. S.; Harish, K. V.; Sangappa; Shetty, G. Rajesha

    2015-06-24

    The present work looks into the structural and mechanical properties modification in ZnO nanoparticle incorporated Hydroxypropyl methylcellulose (HPMC) polymer films, induced by gamma irradiation. The irradiation process was performed in gamma chamber at room temperature by use of Cobalt-60 source (Average energy of 1.25MeV) at different doses: 0, 50, 100, 150 and 200 kGy respectively. The changes in structural parameters and mechanical properties in pure and gamma irradiated HPMC/ZnO nanocomposite films have been studied using X-ray scattering (XRD) data and universal testing machine (UTM). It is found that gamma irradiation decreases the structural parameters and improves the mechanical properties of nanocomposite films.

  8. Comparative Effects of Gamma Irradiation and Ozone Treatment on Hygienic Quality of Korean Red Ginseng Powder

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Yook, Hong-Sun; Kang, Il-Jun; Chung, Cha-Kwon; Kwon, Joong-Ho; Choi, Kang-Ju

    1998-06-01

    For the purpose of improving hygienic quality of Korean red ginseng powder, the comparative effects of gamma irradiation and ozone treatment on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of the red ginseng powder. Physicochemical properties including compositions of the red ginseng saponin (ginsenosides) and fatty acids, pH and hydrogen doanting activity were not significantly changed by gamma irradiation, whereas, ozone treatment caused significant changes in fatty acid compositions, TBA value, pH, acidity and hydrogen donating activity. The results from this study led us to conclude that gamma irradiation was more effective than ozone treatment both for the improvement of hygienic quality and for the maintenance of physicochemical quality of red ginseng powder.

  9. Postharvest Control of Botrytis cinerea and Monilinia fructigena in Apples by Gamma Irradiation Combined with Fumigation.

    PubMed

    Cheon, Wonsu; Kim, Young Soo; Balaraju, Kotnala; Kim, Bong-Su; Lee, Byeong-Ho; Jeon, Yongho

    2016-08-01

    To extend the shelf life of apples in South Korea, we evaluated the effect of gamma irradiation alone or gamma irradiation combined with fumigation on the control of postharvest decay caused by Botrytis cinerea and Monilinia fructigena. An irradiation dose of 1.0 kGy caused the maximal inhibition of B. cinerea and M. fructigena spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.76 and 0.78 kGy for B. cinerea and M. fructigena, respectively. Inhibition of conidial germination of both fungal pathogens occurred at a greater level at the doses of 0.2 to 1.0 kGy compared with the nontreated control; 0.2 kGy caused 90.5 and 73.9% inhibition of B. cinerea and M. fructigena, respectively. Treatment in vitro with the ecofriendly fumigant ethanedinitrile had a greater effect compared with the nontreated control. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments. Interestingly, when irradiation was combined with fumigation, the percentage of disease inhibition increased more at lower (<0.4 kGy) than at higher doses of irradiation, suggesting that the combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions.

  10. Postharvest Control of Botrytis cinerea and Monilinia fructigena in Apples by Gamma Irradiation Combined with Fumigation.

    PubMed

    Cheon, Wonsu; Kim, Young Soo; Balaraju, Kotnala; Kim, Bong-Su; Lee, Byeong-Ho; Jeon, Yongho

    2016-08-01

    To extend the shelf life of apples in South Korea, we evaluated the effect of gamma irradiation alone or gamma irradiation combined with fumigation on the control of postharvest decay caused by Botrytis cinerea and Monilinia fructigena. An irradiation dose of 1.0 kGy caused the maximal inhibition of B. cinerea and M. fructigena spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.76 and 0.78 kGy for B. cinerea and M. fructigena, respectively. Inhibition of conidial germination of both fungal pathogens occurred at a greater level at the doses of 0.2 to 1.0 kGy compared with the nontreated control; 0.2 kGy caused 90.5 and 73.9% inhibition of B. cinerea and M. fructigena, respectively. Treatment in vitro with the ecofriendly fumigant ethanedinitrile had a greater effect compared with the nontreated control. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments. Interestingly, when irradiation was combined with fumigation, the percentage of disease inhibition increased more at lower (<0.4 kGy) than at higher doses of irradiation, suggesting that the combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions. PMID:27497129

  11. Effects of gamma irradiation as a quarantine treatment on development of codling moth larvae

    SciTech Connect

    Burditt, A.K. Jr.; Moffitt, H.R.; Hungate, F.P.

    1985-03-01

    Codling moth, Cydia pomonella (L.), larvae were exposed to gamma radiation at doses upto 160 Gy. Following irradiation the larvae were permited further development, pupation and adult emergence. The number of adults emerging, mature larvae and pupae present were determined. Data from these studies will be used to predict doses of gamma irradiation required as a quarantine treatment to prevent emergence of codling moth adults from fruit infested by larvae. 5 refs., 1 tab.

  12. Modifications induced by gamma irradiation to Makrofol polymer nuclear track detector

    PubMed Central

    Tayel, A.; Zaki, M.F.; El Basaty, A.B.; Hegazy, Tarek M.

    2014-01-01

    The aim of the present study was extended from obtaining information about the interaction of gamma rays with Makrofol DE 7-2 track detector to introduce the basis that can be used in concerning simple sensor for gamma irradiation and bio-engineering applications. Makrofol polymer samples were irradiated with 1.25 MeV 60Co gamma radiations at doses ranging from 20 to 1000 kG y. The modifications of irradiated samples so induced were analyzed using UV–vis spectrometry, photoluminescence spectroscopy, and the measurements of Vickers’ hardness. Moreover, the change in wettability of irradiated Makrofol was investigated by the contact angle determination of the distilled water. UV–vis spectroscopy shows a noticeable decrease in the energy band gap due to gamma irradiation. This decrease could be attributed to the appearance of a shift to UV spectra toward higher wavelength region after irradiation. Photoluminescence spectra reveal a remarkable change in the integrated photoluminescence intensity with increasing gamma doses, which may be resulted from some matrix disorder through the creation of some defected states in the irradiated polymer. The hardness was found to increase from 4.78 MPa for the unirradiated sample to 23.67 MPa for the highest gamma dose. The contact angle investigations show that the wettability of the modified samples increases with increasing the gamma doses. The result obtained from present investigation furnishes evidence that the gamma irradiations are a successful technique to modify the Makrofol DE 7-2 polymer properties to use it in suitable applications. PMID:25750755

  13. Improvement of shelf stability and processing properties of meat products by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Lee, Ju-Woon; Yook, Hong-Sun; Lee, Kyong-Haeng; Kim, Hee-Yun

    2002-03-01

    To evaluate the effects of gamma irradiation on the processing properties of meat products, emulsion-type sausage, beef patties and pork loin ham were manufactured. Most contaminated bacteria were killed by 3 kGy-irradiation to raw ground beef, and sausage can be manufactured with desirable flavor, a reduction of NaCl and phosphate, and extension of shelf life using gamma irradiation on the raw meat. The beef patties were manufactured with the addition of antioxidants (200 ppm), BHA, ascorbyl palmitate, α-tocopherol, or β-carotene, and gamma-irradiation. Retardation of lipid oxidation appeared at the patties with an antioxidant. A dose of 5 kGy was observed to be as effective as the use of 200 ppm NaNO 2 to provide and maintain the desired color of the product during storage. After curing, irradiation, heating and smoking could extensively prolong the shelf life of the hams.

  14. Effect of gamma irradiation on microbiological, chemical and sensory characteristics of licorice root product

    NASA Astrophysics Data System (ADS)

    Al-Bachir, M.; Al-Adawi, M. A.; Al-Kaid, A.

    2004-03-01

    Licorice root products were irradiated at doses of 0, 5, 10, 15 and 20 kGy in a 60Co package irradiator. Irradiated and unirradiated samples were stored at room temperatures. Microbial population on product, chemical changes and sensory properties of produced solution of licorice root products were evaluated after 0 and 12 months of storage. The results indicated that gamma irradiation reduced the counts of microorganisms on licorice root products. D10 of total count and klebsiella spp. were about 1.4 and 0.7 kGy, respectively. The mineral ions (Na, Ca and K) concentration in solution produced from irradiated products were lower than non-irradiated ones. Glycyrrhezinic acid and maltose concentration in solution produced from irradiated products were higher than non-irradiated ones. Sensory evaluation indicated that no significant differences ( P<0.05) were found between solution produced from irradiated and unirradiated products in color, flavor, texture, or taste.

  15. Gamma ray irradiated AgFeO{sub 2} nanoparticles with enhanced gas sensor properties

    SciTech Connect

    Wang, Xiuhua; Shi, Zhijie; Yao, Shangwu; Liao, Fan; Ding, Juanjuan; Shao, Mingwang

    2014-11-15

    AgFeO{sub 2} nanoparticles were synthesized via a facile hydrothermal method and irradiated by various doses of gamma ray. The products were characterized with X-ray powder diffraction, UV–vis absorption spectrum and transmission electron microscope. The results revealed that the crystal structure, morphology and size of the samples remained unchanged after irradiation, while the intensity of UV–Vis spectra increased with irradiation dose increasing. In addition, gamma ray irradiation improved the performance of gas sensor based on the AgFeO{sub 2} nanoparticles including the optimum operating temperature and sensitivity, which might be ascribed to the generation of defects. - Graphical abstract: Gamma ray irradiation improved the performance of gas sensor based on the AgFeO{sub 2} nanoparticles including sensitivity and optimum operating temperature, which might be ascribed to the generation of defects. - Highlights: • AgFeO{sub 2} nanoparticles were synthesized and irradiated with gamma ray. • AgFeO{sub 2} nanoparticles were employed to fabricate gas sensors to detect ethanol. • Gamma ray irradiation improved the sensitivity and optimum operating temperature.

  16. Characterization of blends of PP and SBS vulcanized with gamma irradiation

    NASA Astrophysics Data System (ADS)

    González, J.; Albano, C.; Candal, M. V.; Ichazo, M. N.; Hernández, M.

    2005-07-01

    The present work has the objective of analyzing blends of PP with 30 wt% SBS vulcanized with gamma irradiation. In order to do so, SBS was irradiated at 10, 25 and 50 kGy with gamma rays. Results indicate that the gel fraction increases with irradiation dose, varying from 0.3% to 13.0% for the doses employed. Concerning tensile properties, it can be seen that the incorporation of SBS non-irradiated or irradiated decreases Young's modulus, while increasing elongation at break. Respect to thermal studies, it was detected that SBS decreases melting enthalpy of blends, fact that implies a decrease on crystallinity degree, being this effect more noticeable when SBS is irradiated at doses higher than 10 kGy. On the other hand, melting temperature diminishes slightly when adding SBS to PP, but does not show significant variations when SBS is irradiated. PPs MFI decreased with the addition of SBS, being the effect more notorious with irradiation dose. Finally, it can be concluded that SBS can be vulcanized by gamma irradiation, and that the crosslinking degree increases with irradiation dose.

  17. Some microbial, chemical and sensorial properties of gamma irradiated sesame (Sesamum indicum L.) seeds.

    PubMed

    Al-Bachir, Mahfouz

    2016-04-15

    The effect on microbial, chemical and sensorial properties of sesame seeds was determined after irradiation and storage. The sesame seeds were analyzed before and after irradiation with 3, 6 and 9 kGy of gamma irradiation, and after 6 and 12 months of storage. The results showed that gamma irradiation had no significant (p>0.05) effect on the moisture, ash and fat content on sesame seeds. While, small differences, but sometimes significant (p<0.05), on protein and sugar contents were recorded between irradiated and non-irradiated samples. Total acidity percentage decreased significantly (p<0.05), while total volatile basic nitrogen (TVBN) increased significantly (p<0.05) due to irradiation. During storage, total acidity increased (p<0.05) and TVBN decreased (p<0.05). Gamma irradiation reduced the microorganisms of sesame seeds. Samples treated with 3 kGy or more remained completely free of fungi throughout the storage. While, only the samples treated with 9 kGy remained completely free of bacteria at the end of storage period (after 12 months). The scores for taste, flavor, color and texture of irradiated samples were higher, but not significantly (p>0.05) than those of non-irradiated samples. PMID:26616940

  18. Some microbial, chemical and sensorial properties of gamma irradiated sesame (Sesamum indicum L.) seeds.

    PubMed

    Al-Bachir, Mahfouz

    2016-04-15

    The effect on microbial, chemical and sensorial properties of sesame seeds was determined after irradiation and storage. The sesame seeds were analyzed before and after irradiation with 3, 6 and 9 kGy of gamma irradiation, and after 6 and 12 months of storage. The results showed that gamma irradiation had no significant (p>0.05) effect on the moisture, ash and fat content on sesame seeds. While, small differences, but sometimes significant (p<0.05), on protein and sugar contents were recorded between irradiated and non-irradiated samples. Total acidity percentage decreased significantly (p<0.05), while total volatile basic nitrogen (TVBN) increased significantly (p<0.05) due to irradiation. During storage, total acidity increased (p<0.05) and TVBN decreased (p<0.05). Gamma irradiation reduced the microorganisms of sesame seeds. Samples treated with 3 kGy or more remained completely free of fungi throughout the storage. While, only the samples treated with 9 kGy remained completely free of bacteria at the end of storage period (after 12 months). The scores for taste, flavor, color and texture of irradiated samples were higher, but not significantly (p>0.05) than those of non-irradiated samples.

  19. Effects of gamma and electron beam irradiation on the microbial quality of steamed tofu rolls

    NASA Astrophysics Data System (ADS)

    Jia, Qian; Gao, Meixu; Li, Shurong; Wang, Zhidong

    2013-01-01

    The effectiveness of two kinds of radiation processing, gamma and electron beam (ebeam) irradiation, for the inactivation of Staphylococcus aureus, Salmonella enteritidis and Listeria innocua which were inoculated in pre-sterilised steamed tofu rolls was studied. The corresponding effects of both irradiation types on total bacterial counts (TBCs) in commercial steamed tofu rolls available in the market were also examined. The microbiological results demonstrated that gamma irradiation yielded D10 values of 0.20, 0.24 and 0.22 kGy for S. aureus, S. enteritidis and L. innocua, respectively. The respective D10 values for ebeam irradiation were 0.31, 0.35 and 0.27 kGy. Gamma and ebeam irradiation yielded D10 values of 0.48 and 0.43 kGy for total bacterial counts in commercial steamed tofu rolls, respectively. The results suggest that ebeam irradiation has similar effect on decreasing TBCs in steamed tofu rolls, and gamma irradiation is slightly more effective than ebeam irradiation in reducing the populations of pathogenic bacteria. The observed differences in D10-values between them might be due to the significant differences in dose rate applied, and radiation processing of soybean products to improve their microbial quality could be available for other sources of protein.

  20. Using gamma irradiation for the recovery of anthocyanins from grape pomace

    NASA Astrophysics Data System (ADS)

    Ayed, N.; Yu, H.-L.; Lacroix, M.

    2000-03-01

    This research investigated the effect of gamma irradiation from 0 to 9 kGy, packaging in air or under vacuum, or in combination with other treatments for enhancing anthocyanin extraction from grape pomace. Results indicate that the irradiation at 6 kGy and packaging in the presence of a low concentration of sodium metabisulfite yielded the highest value of anthocyanin extraction.

  1. Using gamma irradiation and low temperature on microbial decontamination of red meat in Iran.

    PubMed

    Sedeh, F M; Arbabi, K; Fatolahi, H; Abhari, M

    2007-03-01

    Gamma irradiation can be used as one of the most efficient methods to reduce microorganisms in food. The irradiation of food is used for a number of purposes, including microbiological control, insects control and inhibition of sprouting and delay of senescence of living food. The aim of this study was to study effects of gamma irradiation, refrigeration and frozen storage as the combination process for improvement of red meat shelf-life. The bovine meat samples were treated with 0, 0.5, 1, 2 and 3 kGy of gamma irradiation and kept in refrigerator for 3 weeks and in freezer for 8 months. The control and irradiated samples were stored at 4-7°C and at -18°C for refrigeration and frozen storage, respectively; and microbial and chemical analyze was done at 1 week and 2 months intervals. In this study the optimum dose of gamma radiation in order to decrease the total count of Mesophilic bacteria, Coliforms, Staphylococcus aureus and especially for elimination of Salmonella was obtained at 3 kGy. Microbial analysis indicated that irradiation and storage at low temperature had a significant effect on the reduction of microbial loads. There was no significant difference in chemical characteristics during freezing storage in bovine meat. Also, irradiated meat samples (3 kGy) were stored in 4-7°C for 14 days, compared to 3 days for non irradiated samples. PMID:23100643

  2. Structural ordering of multi-walled carbon nanotubes (MWCNTs) caused by gamma (γ)-ray irradiation

    SciTech Connect

    Silambarasan, D. Vasu, V.; Iyakutti, K.; Asokan, K.

    2015-06-24

    Multi-walled carbon nanotubes (MWCNTs) were irradiated by Gamma (γ)-rays in air with absorbed doses of 25 and 50 kGy. As a result of γ-ray irradiation, the inter-wall distance of MWCNTs was decreased and their graphitic order was improved. The reduction in inter-wall distance and structural ordering was improved with the increasing dosage of irradiation. Experimental evidences are provided by powder XRD and micro-Raman analyses.

  3. Photorecovery of gamma irradiated cultures of blue-green alga, Anacystis nidulans.

    NASA Technical Reports Server (NTRS)

    Asato, Y.

    1971-01-01

    Evidence is given for photorecovery of Anacystis nidulans after exposures to Co 60 gamma radiation. After irradiation the levels of viable cells were higher in cultures kept in white light than in cultures kept dark for 24 hr. The post-irradiation survival rate increase after 30-min exposures to visible light is demonstrated in cultures irradiated with 35 krad. An increase in survival rates was not observed after exposures to ?red' light.

  4. Effect of gamma irradiation on mistletoe (Viscum album) lectin-mediated toxicity and immunomodulatory activity☆

    PubMed Central

    Sung, Nak-Yun; Byun, Eui-Baek; Song, Du-Sup; Jin, Yeung-Bae; Kim, Jae-Kyung; Park, Jong-Heum; Song, Beom-Seok; Jung, Pil-Mun; Byun, Myung-Woo; Lee, Ju-Woon; Park, Sang-Hyun; Kim, Jae-Hun

    2013-01-01

    This study evaluated the effect of gamma irradiation on the reduction of the toxicity of mistletoe lectin using both in vitro and in vivo models. To extract the lectin from mistletoe, an (NH4)2SO4 precipitation method was employed and the precipitant purified using a Sepharose 4B column to obtain the pure lectin fraction. Purified lectin was then gamma-irradiated at doses of 0, 5, 10, 15, and 20 kGy, or heated at 100 °C for 30 min. Toxic effects of non-irradiated, irradiated, and heat-treated lectins were tested using hemagglutination assays, cytotoxicity assays, hepatotoxicity, and a mouse survival test and immunological response was tested using cytokine production activity. Hemagglutination of lectin was remarkably decreased (P < 0.05) by irradiation at doses exceeding 10 kGy and with heat treatment. However, lectin irradiated with 5 kGy maintained its hemagglutination activity. The cytotoxicity of lectin was decreased by irradiation at doses over 5 kGy and with heat treatment. In experiments using mouse model, glutamate oxaloacetate transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels were decreased in the group treated with the 5 kGy irradiated and heat-treated lectins as compared to the intact lectin, and it was also shown that 5 kGy irradiated and heat-treated lectins did not cause damage in liver tissue or mortality. In the result of immunological response, tumor necrosis factor (TNF-α) and interleukin (IL-6) levels were significantly (P < 0.05) increased in the 5 kGy gamma-irradiated lectin treated group. These results indicate that 5 kGy irradiated lectin still maintained the immunological response with reduction of toxicity. Therefore, gamma-irradiation may be an effective method for reducing the toxicity of lectin maintaining the immune response. PMID:23847758

  5. Performance degradation of QAM based inter-satellite optical communication system under gamma irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Zhao, Shanghong; Gong, Zizheng; Zhao, Jing; Li, Xuan

    2016-01-01

    Main devices in quadrature amplitude modulation (QAM) based inter-satellite optical communication system were irradiated to a total dose of 20 krad with the dose rate of 5 rad/s using a Co60 radiation source. Gamma irradiation impacts on devices were analyzed and on the basis, system performance degradation was simulated. Variety of system BER along with onboard working time for different inter-satellite links was presented. In addition, some adaption methods were proposed to reduce gamma irradiation induced degradation.

  6. Combined effects of gamma-irradiation and modified atmosphere packaging on quality of some spices.

    PubMed

    Kirkin, Celale; Mitrevski, Blagoj; Gunes, Gurbuz; Marriott, Philip J

    2014-07-01

    Thyme (Thymus vidgaris L.), rosemary (Rosmarinus officinalis L.), black pepper (Piper nigrum L.) and cumin (Cuminum cyminum L.) in ground form were packaged in either air or 100% N2 and γ-irradiated at 3 different irradiation levels (7kGy, 12kGy, 17kGy). Total viable bacterial count, yeast and mould count, colour, essential oil yield and essential oil composition were determined. Microbial load was not detectable after 12kGy irradiation of all samples. Irradiation resulted in significant changes in colour values of rosemary and black pepper. The discolouration of the irradiated black pepper was lower in modified atmosphere packaging (MAP) compared to air packaging. Essential oil yield of irradiated black pepper and cumin was lower in air packaging compared to MAP. Gamma-irradiation generally decreased monoterpenes and increased oxygenated compounds, but the effect was lower in MAP. Overall, spices should be irradiated under an O2-free atmosphere to minimise quality deterioration.

  7. Molecular structure and physicochemical properties of potato and bean starches as affected by gamma-irradiation.

    PubMed

    Chung, Hyun-Jung; Liu, Qiang

    2010-08-01

    In this study, potato and bean starches were treated by gamma-irradiation up to 50kGy. Molecular structure and physicochemical properties of irradiated potato and bean starches were investigated. Microscopic observation under scanning electron microscope (SEM) and polarized microscope showed that some of potato and bean starch granules were destroyed by gamma-irradiation and the breakage was much greater at a higher dose (50 kGy). Carboxyl content and amylose leaching increased, whereas the swelling factor and apparent amylose content decreased after irradiation in both potato and bean starches. The proportions of short (DP 6-12) and long (DP > or = 37) amylopectin chains as well as average chain length increased with increasing irradiation dose. However, the proportion of DP 13-24 decreased by irradiation. The relative crystallinity, the degree of granule surface order, and gelatinization enthalpy decreased with an increase in irradiation dose. The extent of decrease in potato starch was greater than that in bean starch. The exothermic peak around 90-110 degrees C was observed in DSC thermogram when the potato starch was irradiated at 50 kGy. The pasting viscosity significantly decreased with an increase in irradiation dose. The proportion of slowly digestible starch (SDS) decreased and resistant starch (RS) content increased by irradiation in both potato and bean starches. However, the rapidly digestible starch (RDS) of potato starch increased with increasing irradiation dose, whereas the bean starch showed the opposite trend to potato starch in RDS content.

  8. Characterization of gamma irradiated petrolatum eye ointment base by headspace-gas chromatography-mass spectrometry.

    PubMed

    Hong, Lan; Altorfer, Hans

    2002-06-20

    The effects of gamma irradiation on petrolatum eye ointment base (EOB) and its ingredients (white petrolatum, liquid paraffin, and wool fat) were studied at different irradiation doses. Forty-one volatile radiolysis products were detected and identified by a combined system of headspace-gas chromatography-mass spectrometry (HS-GC-MS). The characteristics of the radiolysis products and the degradation pathway were discussed in each case, respectively. GC method demonstrates that the component distribution patterns of eye ointment as well as its individual ingredients have no differences before and after gamma irradiation. The influence of gamma treatment on EOB was quantitatively determined at 15, 25 and 50 kGy. The concentrations of the radiolysis products increase linearly with increasing doses. Both qualitative and quantitative data show that irradiated eye ointment is safe for human use.

  9. Effect of gamma irradiation on the reproductive system of the pond snail Physa acuta

    SciTech Connect

    Fujita, S.; Egami, N.

    1984-05-01

    Changes in the survival rate in adults and embryos of the pond snail Physa acuta were studied after acute whole-body ..gamma.. irradiation. The LD/sub 50/ value of the adult snails was about 40 kR. The LD/sub 50/ values of the embryos irradiated 0 and 1 day after oviposition were about 0.9 and 2 kR, respectively. Histological changes in the ovotestis, the number of eggs laid, and their hatchability were examined in the irradiated adult snails. A fall and a subsequent recovery were observed for these characteristics after irradiation with 8 kR of ..gamma.. rays. The relative constitution of the germ-cell populations was greatly changed by the same dose of ..gamma.. rays. After depletion, the ovotestis was first repopulated with gonia, and then with oocytes, spermatocytes, and spermatids.

  10. Recycling of gamma irradiated inner tubes in butyl based rubber compounds

    NASA Astrophysics Data System (ADS)

    Karaağaç, Bağdagül; Şen, Murat; Deniz, Veli; Güven, Olgun

    2007-12-01

    Recycling of gamma irradiated inner tubes made of butyl rubber in butyl based rubber compounds was studied. Gamma irradiated inner tube wastes and commercial butyl rubber crumbs devulcanized by conventional methods were replaced with butyl rubber up to 15 phr in the compound recipe. The rheological and mechanical properties and carbon black dispersion degree for both types of compounds were measured and then compared to those of virgin butyl rubber compound. It is well known that mechanical properties are deteriorated when rubber crumb is added to the virgin compound. The deterioration in the mechanical properties for the compounds prepared by recycling of irradiated inner tubes at 120 kGy is much lower than the compounds prepared by using commercial butyl crumbs. It has been observed that gamma irradiated used inner tubes were compatible with butyl rubber and could be recycled within butyl based rubber compounds.

  11. Effect of low dose gamma irradiation on plant and grain nutrition of wheat

    NASA Astrophysics Data System (ADS)

    Singh, Bhupinder; Datta, Partha Sarathi

    2010-08-01

    We recently reported the use of low dose gamma irradiation to improve plant vigor, grain development and yield attributes of wheat ( Singh and Datta, 2010). Further, we report here the results of a field experiment conducted to assess the effect of gamma irradiation at 0, 0.01, 0.03, 0.05, 0.07 and 0.1 kGy on flag leaf area, stomatal conductance, transpiration and photosynthetic rate and plant and grain nutritional quality. Gamma irradiation improved plant nutrition but did not improve the nutritional quality of grains particularly relating to micronutrients. Grain carotene, a precursor for vitamin A, was higher in irradiated grains. Low grain micronutrients seem to be caused by a limitation in the source to sink nutrient translocation rather than in the nutrient uptake capacity of the plant root.

  12. Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials.

    PubMed

    Carvalho, Fabíola Galbiatti de; Fucio, Suzana Beatriz Portugal de; Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Correr-Sobrinho, Lourenço; Puppin-Rontani, Regina Maria

    2009-01-01

    This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm(2) area). G1 and G3 were sterilized with a 14.5 KGy dose at 27 degrees C for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (alpha=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials. PMID:19738944

  13. Comparison of the efficacy of gamma and UV irradiation in sanitization of fresh carrot juice

    NASA Astrophysics Data System (ADS)

    Jo, Cheorun; Lee, Kyung Haeng

    2012-08-01

    As there is no pasteurization procedure for the manufacture of fresh vegetable juice, both industry and consumers have sought a method for improving the storage stability and shelf-life of this category of products. In this study, the effects of commercially available, non-thermal pasteurization processes, such as gamma and UV irradiation, were compared for their efficacy in sanitizing fresh carrot juice (FCJ). FCJ was manufactured, packaged, and gamma irradiated with doses of 0, 1, 3, and 5 kGy. The manufactured FCJ was also passed through 4 UV light lamps at doses of 3.67, 4.69, and 6.50 kGy. The total aerobic bacterial count of the FCJ approached the legal limit (105 CFU/mL) after manufacturing. Both treatments were effective in reducing the number of total aerobic bacteria, and the reduced number was maintained during storage for 7 days. Gamma irradiation was more effective in suppressing microbial growth during storage. When the doses for UV treatment and gamma irradiation were higher, the inactivation effects were higher. The reduction of ascorbic acid content was greater upon gamma irradiation than UV treatment. No difference was found in the contents of flavonoids and polyphenols in FCJ after either treatment. After 3 days of refrigerated storage, the sensory scores of gamma- or UV-irradiated FCJ were superior to those of the control. The results indicate that both non-thermal treatments were effective in improving storage stability and extending shelf-life, but gamma irradiation was slightly better in suppressing microbial growth after treatment.

  14. Mathematical modeling of drug release from bioerodible microparticles: effect of gamma-irradiation.

    PubMed

    Faisant, N; Siepmann, J; Richard, J; Benoit, J P

    2003-09-01

    Bioerodible polymers used in controlled drug delivery systems, such as poly(lactic-co-glycolic acid) (PLGA) undergo radiolytic degradation during gamma-irradiation. In spite of the considerable practical importance, yet only little knowledge is available on the consequences of this sterilization method on the resulting drug release patterns in a quantitative way. The major objectives of the present study were: (i) to monitor the effects of different gamma-irradiation doses on the physicochemical properties of drug-free and drug-loaded, PLGA-based microparticles; (ii) to analyze the obtained experimental results using adequate mathematical models; (iii) to get further insight into the occurring physical and chemical phenomena; and (iv) to relate the applied gamma-irradiation dose in a quantitative way to the resulting drug release rate. 5-Fluorouracil-loaded, PLGA-based microparticles were prepared with an oil-in-water solvent extraction method and exposed to gamma-irradiation doses ranging from 0 to 33 kGy. Size exclusion chromatography, differential scanning calorimetry, scanning electron microscopy, particle size analysis, determination of the actual drug loading and in vitro drug release kinetics were used to study the effects of the gamma-irradiation dose on the physicochemical properties of the microparticles. Two mathematical models-a simplified and a more comprehensive one-were used to analyze the experimental results. The simplified model considers drug diffusion based on Fick's second law for spherical geometry and a Higuchi-like pseudo-steady-state approach. The complex model combines Monte Carlo simulations (describing polymer erosion) with partial differential equations quantifying drug diffusion with time-, position- and direction-dependent diffusivities. Interestingly, exponential relationships between the gamma-irradiation dose and the initial drug diffusivity within the microparticles could be established. Based on this knowledge both models were

  15. Sterilization and protection of protein in combinations of Camellia sinensis green tea extract and gamma irradiation.

    PubMed

    Saloua, Kouass Sahbani; Salah, Kouass; Nasreddine, Benbettaieb; Samia, Ayari; Mouldi, Saidi; Ahmed, Landoulsi

    2011-04-01

    Sterilization of milk protein without heating is of great interest. Gamma irradiation is a very powerful method to decontaminated casein. Gamma-irradiation of proteins in aqueous media at doses higher than 5kGy is known to induce their aggregation (without oxygen) or degradation (in presence of oxygen). Camellia sinensis green tea extract addition before irradiation of caseins cow milk proteins was examined. It was found that the presence of C. sinensis green tea extract during irradiation in the presence of oxygen conditions prevented the protein aggregation even at doses higher than 10kGy, probably by scavenging oxygen radicals produced by irradiation. The protective role of C. sinensis green tea extract allowing the gamma-irradiation treatment of caseins cow milk proteins in solution, was asserted by sodium dodecyl-sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and by high performance liquid chromatography inverse phase (RP-HPLC). The total viable microorganisms content evaluated by Plate Count Agar (PCA) incubation for 12h at 37°C, showed that caseins protein preparations gamma-irradiated remained sterile at a dose 2kGy in absence of C. sinensis green tea extract and at a dose lower than 2kGy in the presence of C. sinensis green tea extract.

  16. Identification of gamma-irradiated papaya, melon and watermelon

    NASA Astrophysics Data System (ADS)

    Marín-Huachaca, Nélida S.; Mancini-Filho, Jorge; Delincée, Henry; Villavicencio, Anna Lúcia C. H.

    2004-09-01

    Ionizing radiation can be used to control spoilage microorganisms and to increase the shelf life of fresh fruits and vegetables in replacement for the treatment with chemical fumigants. In order to enforce labelling regulations, methods for detecting the irradiation treatment directly in the produce are required. Recently, a number of detection methods for irradiated food have been adopted by the Codex Comission. A rapid screening method for qualitative detection of irradiation is the DNA Comet Assay. The applicability of the DNA Comet Assay for distinguishing irradiated papaya, melon, and watermelon was evaluated. The samples were treated in a 60Co facility at dose levels of 0.0, 0.5, 0.75, and 1.0kGy. The irradiated samples showed typical DNA fragmentation whereas cells from non-irradiated ones appeared intact. In addition to the DNA Comet Assay also the half-embryo test was applied in melon and watermelon to detect the irradiation treatment.

  17. Studies on the physicochemical characteristics of oil extracted from gamma irradiated pistachio (Pistacia vera L.).

    PubMed

    Al-Bachir, Mahfouz

    2015-01-15

    The present study evaluated the quality of pistachio oil, as a function of irradiation, to determine the dose level causing undesirable changes to pistachio oil. Physicochemical fatty acid composition, acidity value, peroxide value, iodine value specification number, thiobarbituric acid (TBA) value and colour of pistachio oil extracted from samples treated with 0, 1, 2 and 3 kGy doses of gamma irradiation were determined. Gamma irradiation caused the alteration of fatty acids of pistachio oil which showed a decrease in oleic acid (C18:1) and an increase in linoleic acid (C18:2). All other fatty acids remained unaffected after irradiation. The higher used doses (2 and 3 kGy) decreased acidity value, peroxide value and iodine value, and increased specification number, with no effect on TBA value. Irradiation had a significant effect on colour values of pistachio oil. Parameters L, a and b increased at doses of 1 and 2 kGy.

  18. A preliminary study on viral decontamination of chicken serum using gamma-irradiation.

    PubMed

    Hamar, Gergely; Misák, Ferenc; Palya, Vilmos; de Foucauld, Jean

    2010-05-01

    A preliminary experiment was carried out to determine whether a decontamination procedure using gamma irradiation, similar to that adopted in the European guideline for bovine serum contaminated by pestivirus, could be applied to chicken serum. Chicken sera spiked with known amounts of enveloped and non-enveloped chicken viruses were gamma irradiated. The remaining live viruses were then measured by titration and the virus reduction capacity of the irradiation process was established for both enveloped and non-enveloped virus models. In parallel with the irradiation procedure, a classical in vivo extraneous agent test was also evaluated in order to see if it has the capacity to detect low enough levels of live viruses to be used for testing irradiated serum. The results suggest that the principles of the bovine serum decontamination procedure may be applied to chicken serum. Further studies are required to determine if this process would provide an acceptable solution for the viral 'decontamination' of chicken serum.

  19. Hepatoprotective effects of gamma-irradiated caraway essential oils in experimental sepsis.

    PubMed

    Fatemi, F; Allameh, A; Khalafi, H; Ashrafihelan, J

    2010-02-01

    Irradiation is an important method of processing herbal drugs, while our understanding of the effects of gamma-irradiation on pharmacological properties of seed products such as caraway essential oils is however still very limited. In this study, caraway seeds were irradiated at dose levels of 0, 10 and 25kGy. After extracting the essential oils, the effects of fresh and gamma-irradiated caraway oils (100mg/kg b.w) on preventing septic-related oxidative liver injury induced by cecal ligation and puncture (CLP) model were investigated by measuring oxidative stress parameters in the liver. CLP operation caused a marked increase in myeloperoxidase (MPO) activity which was readily reversed in rats treated with fresh and irradiated caraway oils. Likewise, thiobarbituric acid reactive substances (TBARS) level in the liver was compensated in rats treated with the fresh and irradiated caraway oils. Moreover, liver GSH which was initially depleted due to CLP was recovered by essential oil treatments. The protective role of oils was further confirmed by showing that liver function tests (ALT/AST) as well as histopathological changes following CLP operation were recovered in rats treated with oils from either fresh or irradiated caraway seeds. These data may suggest that gamma-irradiation to caraway seeds at 10 and 25kGy has no influence on the antioxidative properties of caraway essential oils.

  20. Effect of gamma irradiation on the hemocyte-mediated immune response of Aedes aegypti against microfilariae

    SciTech Connect

    Christensen, B.M.; Huff, B.M.; Li, J. )

    1990-07-01

    The effect of gamma irradiation on the melanotic encapsulation response of Aedes aegypti black eye Liverpool strain against inoculated Dirofilaria immitis microfilariae (mff) was assessed at 1, 2, 3, and 6 days postinoculation (PI). Mosquitoes received 6000 rad from a 137Cs source (Shepard Mark I irradiator) at 3 days postemergence and were inoculated with 15-20 mff 24 hr later. These mosquitoes were compared to nonirradiated controls that also were inoculated with 15-20 mff at 3 days postemergence. The immune response was significantly reduced in irradiated mosquitoes as compared with controls at all days PI. Although the response was significantly inhibited compared with controls, irradiated mosquitoes were still capable of eliciting a response against 69% of recovered mff at 6 days PI. External gamma irradiation did not significantly affect the proliferation of hemocytes associated with the melanotic encapsulation response of A. aegypti. The number of circulating hemocytes increased in irradiated mosquitoes in response to inoculated mff in a manner similar to nonirradiated, inoculated controls. Hemocyte monophenol oxidase activity, however, was significantly reduced in gamma-irradiated mosquitoes at 12 hr PI as compared with controls. The reduced immunological capacity of irradiated mosquitoes might be related to an interference with gene activity required for the synthesis or activation of enzymes that are directly or indirectly involved in the biochemical processes associated with the production of melanotic substances that sequester mff.

  1. Texture, color, lipid oxidation and sensory acceptability of gamma-irradiated marinated anchovy fillets

    NASA Astrophysics Data System (ADS)

    Tomac, Alejandra; Cova, María C.; Narvaiz, Patricia; Yeannes, María I.

    2015-01-01

    The effect of gamma irradiation (0, 2, 3 and 4 kGy) on vacuum-packed marinated anchovy fillets was analyzed for their texture, color, lipid oxidation and sensory acceptability after 10 months under refrigeration. Marinated (3% acetic acid, 10% sodium chloride and 0.2% citric acid) Engraulis anchoita fillets were vacuum-packed and irradiated with a cobalt-60 source at a semi-industrial irradiation facility. The irradiation caused a slight increase in hardness values regardless of the applied dose but maintained a consistent texture over the 10 months, even though the control samples softened, most likely due to degradation. This hardness increase did not affect the textural sensory acceptability. Irradiation did not modify the color but still reduced color changes during storage, benefitting the product's quality. TBARS was increased in every sample throughout storage, but irradiation decreased these values. Sensory acceptability was not affected by gamma irradiation. Therefore, gamma irradiation could be successfully applied to this type of product for the purpose of shelf-life extension.

  2. Poly(ADP-ribose) polymerase inhibition reverses vascular dysfunction after {gamma}-irradiation

    SciTech Connect

    Beller, Carsten J. . E-mail: Carsten.Beller@urz.uni-heidelberg.de; Radovits, Tamas; Seres, Leila; Kosse, Jens; Krempien, Robert; Gross, Marie-Luise; Penzel, Roland; Berger, Irina; Huber, Peter E.; Hagl, Siegfried; Szabo, Csaba; Szabo, Gabor

    2006-08-01

    Purpose: The generation of reactive oxygen species during {gamma}-irradiation may induce DNA damage, leading to activation of the nuclear enzyme poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) culminating in endothelial dysfunction. In the present study, we assessed the effect of PARP inhibition on changes in vascular function after acute and short-term irradiation. Methods and Materials: In the acute experiments, aortic rings were exposed to 20 Gy of {gamma}-irradiation. The aortae were harvested after 1 or 7 days. Two additional groups received the ultrapotent PARP inhibitor, INO-1001, for 1 or 7 days after irradiation. The aortic rings were precontracted by phenylephrine and relaxation to acetylcholine and sodium nitroprusside were studied. Results: The vasoconstrictor response to phenylephrine was significantly lower both acutely and 1 and 7 days after irradiation. Vasorelaxation to acetylcholine and sodium nitroprusside was not impaired acutely after irradiation. One and seven days after irradiation, vasorelaxation to acetylcholine and sodium nitroprusside was significantly enhanced. Treatment with INO-1001 reversed vascular dysfunction after irradiation. Conclusion: Vascular dysfunction was observed 1 and 7 days after irradiation, as evidenced by reduced vasoconstriction, coupled with endothelium-dependent and -independent hyperrelaxation. PARP inhibition restored vascular function and may, therefore, be suitable to reverse vascular dysfunction after irradiation.

  3. Gamma irradiation: effects on biomechanical properties of human bone-patellar tendon-bone allografts.

    PubMed

    Fideler, B M; Vangsness, C T; Lu, B; Orlando, C; Moore, T

    1995-01-01

    Sixty 10-mm bone-patellar tendon-bone allografts from young human donors were placed into four test groups, a control fresh-frozen group and three fresh-frozen irradiated groups. The irradiated groups were exposed to 2.0, 3.0, or 4.0 Mrad of gamma irradiation. The specimens were tested to tensile failure. The initial biomechanical strength of fresh-frozen allografts was reduced up to 15% when compared with fresh-frozen controls after 2.0 Mrad of irradiation. Maximum force, strain energy, modulus, and maximum stress demonstrated a statistically significant reduction after 2.0 Mrad of irradiation (P < 0.01). Stiffness, elongation, and strain were reduced but not with statistical significance. A 10% to 24% and 19% to 46% reduction in all biomechanical properties were found after 3.0 (P < 0.005) and 4.0 (P < 0.0005) Mrad of irradiation, respectively. After irradiation with a 4.0 Mrad dose, the ultimate load was below that of reported values for the human anterior cruciate ligament. It is clinically important to observe and document changes in human ligaments that result from currently used doses of gamma irradiation. The results from this study provide important information regarding the initial biomechanical properties of fresh-frozen human bone-patellar tendon-bone allografts after bacterial sterilization with gamma irradiation. The current accepted dose for sterilization is between 1.5 and 2.5 Mrad. There appeared to be a dose-dependent effect of irradiation on all the biomechanical parameters studied. Four of seven parameters were found to be reduced after 2.0 Mrad of irradiation. Reductions were found in all parameters after 3.0 and 4.0 Mrad of irradiation.

  4. EPR study on gamma-irradiated fruits dehydrated via osmosis

    NASA Astrophysics Data System (ADS)

    Yordanov, N. D.; Aleksieva, K.

    2007-06-01

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit "sugar-like" EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

  5. Validation of gamma irradiator controls for quality and regulatory compliance

    NASA Astrophysics Data System (ADS)

    Harding, Rorry B.; Pinteric, Francis J. A.

    1995-09-01

    Since 1978 the U.S. Food and Drug Administration (FDA) has had both the legal authority and the Current Good Manufacturing Practice (CGMP) regulations in place to require irradiator owners who process medical devices to produce evidence of Irradiation Process Validation. One of the key components of Irradiation Process Validation is the validation of the irradiator controls. However, it is only recently that FDA audits have focused on this component of the process validation. What is Irradiator Control System Validation? What constitutes evidence of control? How do owners obtain evidence? What is the irradiator supplier's role in validation? How does the ISO 9000 Quality Standard relate to the FDA's CGMP requirement for evidence of Control System Validation? This paper presents answers to these questions based on the recent experiences of Nordion's engineering and product management staff who have worked with several US-based irradiator owners. This topic — Validation of Irradiator Controls — is a significant regulatory compliance and operations issue within the irradiator suppliers' and users' community.

  6. Evaluating the Effects of Gamma-Irradiation for Decontamination of Medicinal Cannabis.

    PubMed

    Hazekamp, Arno

    2016-01-01

    In several countries with a National medicinal cannabis program, pharmaceutical regulations specify that herbal cannabis products must adhere to strict safety standards regarding microbial contamination. Treatment by gamma irradiation currently seems the only method available to meet these requirements. We evaluated the effects of irradiation treatment of four different cannabis varieties covering different chemical compositions. Samples were compared before and after standard gamma-irradiation treatment by performing quantitative UPLC analysis of major cannabinoids, as well as qualitative GC analysis of full cannabinoid and terpene profiles. In addition, water content and microscopic appearance of the cannabis flowers was evaluated. This study found that treatment did not cause changes in the content of THC and CBD, generally considered as the most important therapeutically active components of medicinal cannabis. Likewise, the water content and the microscopic structure of the dried cannabis flowers were not altered by standard irradiation protocol in the cannabis varieties studied. The effect of gamma-irradiation was limited to a reduction of some terpenes present in the cannabis, but keeping the terpene profile qualitatively the same. Based on the results presented in this report, gamma irradiation of herbal cannabis remains the recommended method of decontamination, at least until other more generally accepted methods have been developed and validated. PMID:27199751

  7. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L.

    NASA Astrophysics Data System (ADS)

    Tahir, D.; Halide, H.; Wahab, A. W.; Kurniawan, D.

    2014-09-01

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  8. Gamma irradiation effects and EPR investigation on poly(lactide-co-glycolide) microspheres containing bupivacaine.

    PubMed

    Montanari, L; Cilurzo, F; Conti, B; Genta, I; Groppo, A; Valvo, L; Faucitano, A; Buttafava, A

    2002-06-01

    The effects of gamma radiation on the stability of microspheres made of a polylactide-co-glycolide 50:50 copolymer (PLGA) and loaded with 40% bupivacaine (BU) were studied. The radiolysis mechanisms of BU and BU-loaded microspheres were investigated by using electronic paramagnetic resonance (EPR) analysis. Microspheres were prepared by means of a spray drying method. Gamma Irradiation was carried out in the open, at the dose of 25 kGy, by using a 60Co source. The stability of BU-loaded microspheres was evaluated over a 1-year period on the basis of drug content and dissolution profile. Non-irradiated microspheres were stable over the whole period under consideration. Immediately after irradiation the amount of BU released after 24 h from irradiated microspheres increased from 17 to 25%; in the following 3 months of storage it increased to about 35%, and then it kept constant for 1 year. Radicals generated by BU irradiation were identified by EPR analysis; the sensitivity to gamma radiation of BU was about four times lower than that of PLGA. Furthermore, the EPR spectra of loaded microspheres showed that the relative abundance of BU radicals plus PLGA radicals was proportionate to the electronic fractions of the components; this implies that no spin transfer BU/PLGA had occurred during gamma irradiation. PMID:12088056

  9. ATM is required for rapid degradation of cyclin D1 in response to {gamma}-irradiation

    SciTech Connect

    Choo, Dong Wan; Baek, Hye Jung; Motoyama, Noboru; Cho, Kwan Ho; Kim, Hye Sun; Kim, Sang Soo

    2009-01-23

    The cellular response to DNA damage induced by {gamma}-irradiation activates cell-cycle arrest to permit DNA repair and to prevent replication. Cyclin D1 is the key molecule for transition between the G1 and S phases of the cell-cycle, and amplification or overexpression of cyclin D1 plays pivotal roles in the development of several human cancers. To study the regulation of cyclin D1 in the DNA-damaged condition, we analyzed the proteolytic regulation of cyclin D1 expression upon {gamma}-irradiation. Upon {gamma}-irradiation, a rapid reduction in cyclin D1 levels was observed prior to p53 stabilization, indicating that the stability of cyclin D1 is controlled in a p53-independent manner. Further analysis revealed that irradiation facilitated ubiquitination of cyclin D1 and that a proteasome inhibitor blocked cyclin D1 degradation under the same conditions. Interestingly, after mutation of threonine residue 286 of cyclin D1, which is reported to be the GSK-3{beta} phosphorylation site, the mutant protein showed resistance to irradiation-induced proteolysis although inhibitors of GSK-3{beta} failed to prevent cyclin D1 degradation. Rather, ATM inhibition markedly prevented cyclin D1 degradation induced by {gamma}-irradiation. Our data indicate that communication between ATM and cyclin D1 may be required for maintenance of genomic integrity achieved by rapid arrest of the cell-cycle, and that disruption of this crosstalk may increase susceptibility to cancer.

  10. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L

    SciTech Connect

    Tahir, D. Halide, H. Kurniawan, D.; Wahab, A. W.

    2014-09-25

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  11. Evaluating the Effects of Gamma-Irradiation for Decontamination of Medicinal Cannabis

    PubMed Central

    Hazekamp, Arno

    2016-01-01

    In several countries with a National medicinal cannabis program, pharmaceutical regulations specify that herbal cannabis products must adhere to strict safety standards regarding microbial contamination. Treatment by gamma irradiation currently seems the only method available to meet these requirements. We evaluated the effects of irradiation treatment of four different cannabis varieties covering different chemical compositions. Samples were compared before and after standard gamma-irradiation treatment by performing quantitative UPLC analysis of major cannabinoids, as well as qualitative GC analysis of full cannabinoid and terpene profiles. In addition, water content and microscopic appearance of the cannabis flowers was evaluated. This study found that treatment did not cause changes in the content of THC and CBD, generally considered as the most important therapeutically active components of medicinal cannabis. Likewise, the water content and the microscopic structure of the dried cannabis flowers were not altered by standard irradiation protocol in the cannabis varieties studied. The effect of gamma-irradiation was limited to a reduction of some terpenes present in the cannabis, but keeping the terpene profile qualitatively the same. Based on the results presented in this report, gamma irradiation of herbal cannabis remains the recommended method of decontamination, at least until other more generally accepted methods have been developed and validated. PMID:27199751

  12. The change in dielectric constant, AC conductivity and optical band gaps of polymer electrolyte film: Gamma irradiation

    SciTech Connect

    Raghu, S. Subramanya, K. Sharanappa, C. Mini, V. Archana, K. Sanjeev, Ganesh Devendrappa, H.

    2014-04-24

    The effects of gamma (γ) irradiation on dielectric and optical properties of polymer electrolyte film were investigated. The dielectric constant and ac conductivity increases with γ dose. Also optical band gap decreased from 4.23 to 3.78ev after irradiation. A large dependence of the polymer properties on the irradiation dose was noticed. This suggests that there is a possibility of improving polymer electrolyte properties on gamma irradiation.

  13. Irradiation tests of prototype self-powered gamma and neutron detectors

    SciTech Connect

    Vermeeren, L.; Carcreff, H.

    2011-07-01

    In the framework of the SCK.CEN-CEA Joint Instrumentation Laboratory, we are developing and optimizing a self-powered detector for selective in-core monitoring of the gamma field. Several prototypes with bismuth emitters were developed and tested in a pure gamma field (the PAGURE gamma irradiation facility at CEA) and in mixed neutron and gamma fields (in the OSIRIS reactor at CEA and in the BR2 reactor at SCK.CEN). Detailed MCNP modelling was performed to calculate the gamma and neutron sensitivities. Apart from a few failing prototypes, all detectors showed equilibrium signals proportional to the gamma field with a good long-term stability (under irradiation during several weeks). A tubular geometry design was finally selected as the most appropriate for in-core gamma detection, coupling a larger sensitivity with better response characteristics. In the same experiment in BR2 six prototype Self-Powered Neutron Detectors (SPNDs) with continuous sheaths (i.e. without any weld between the sensitive part and the cable) were extensively tested: two SPNDs with Co emitter, two with V emitter and two with Rh emitters, with varying geometries. All detector responses were verified to be proportional to the reactor power. The prompt and delayed response contributions were quantified. The signal contributions due to the impact of gamma rays were experimentally determined. The evolution of the signals was continuously followed during the full irradiation period. The signal-to-noise level was observed to be well below 1% in typical irradiation conditions. The absolute neutron and gamma responses for all SPNDs are consistent. (authors)

  14. Low Dose Gamma Irradiation Potentiates Secondary Exposure to Gamma Rays or Protons in Thyroid Tissue Analogs

    SciTech Connect

    Green, Lora M

    2006-05-25

    We have utilized our unique bioreactor model to produce three-dimensional thyroid tissue analogs that we believe better represent the effects of radiation in vivo than two-dimensional cultures. Our thyroid model has been characterized at multiple levels, including: cell-cell exchanges (bystander), signal transduction, functional changes and modulation of gene expression. We have significant preliminary data on structural, functional, signal transduction and gene expression responses from acute exposures at high doses (50-1000 rads) of gamma, protons and iron (Green et al., 2001a; 2001b; 2002a; 2002b; 2005). More recently, we used our DOE funding (ending Feb 06) to characterize the pattern of radiation modulated gene expression in rat thyroid tissue analogs using low-dose/low-dose rate radiation, plus/minus acute challenge exposures. Findings from these studies show that the low-dose/low-dose rate “priming” exposures to radiation invoked changes in gene expression profiles that varied with dose and time. The thyrocytes transitioned to a “primed” state, so that when the tissue analogs were challenged with an acute exposure to radiation they had a muted response (or an increased resistance) to cytopathological changes relative to “un-primed” cells. We measured dramatic differences in the primed tissue analogs, showing that our original hypothesis was correct: that low dose gamma irradiation will potentiate the repair/adaptation response to a secondary exposure. Implications from these findings are that risk assessments based on classical in vitro tissue culture assays will overestimate risk, and that low dose rate priming results in a reduced response in gene expression to a secondary challenge exposure, which implies that a priming dose provides enhanced protection to thyroid cells grown as tissue analogs. If we can determine that the effects of radiation on our tissue analogs more closely resemble the effects of radiation in vivo, then we can better

  15. Effect of gamma irradiation on commercial eggs experimentally inoculated with Salmonella enteritidis

    NASA Astrophysics Data System (ADS)

    Tellez, I. G.; Trejo, R. M.; Sanchez, R. E.; Ceniceros, R. M.; Luna, Q. P.; Zazua, P.; Hargis, B. M.

    1995-02-01

    Using intact, fresh shell eggs, inoculated with 10 8 colony-forming units (cfu) of S. enteritidis, the effect of three doses of gamma irradiation on bacteriologic population and physical characteristics (Haugh units and yolk color) of the eggs was determinated. Penetration test area was picked at random just off the air cell of each egg. Aluminum cylinders were attached to the egg surface with a rim of molten paraffin, and 10 8S. enteritidis was then applied to inoculate the egg. Eggs were then irradiated within 2 hours using a Cobalt-60 gamma source at either 1, 2, or 3 kGy. A second set of inoculated, non-irradiated was used as controls. Following irradiation, eggs were maintained at 4°C for 42 hours prior culture. Irradiation with 1 kGy resulted in a significant (P < .05), 3.9 log reduction in detectable S. enteritidis in the shell and a higly significant (P < .025) 95% reduction in detectable S. enteritidis in the internal shell membranes. Irradiation of eggs with either 2 or 3 kGy reduced bacterial contamination to non-detectable levels in both the shell and internal membranes. However, irradiation at either 1, 2 or 3 kGy resulted in a significant (P <- .05) decrease (approximately 50%) in Haugh units. Additionally, irradiation of intact shell eggs at 2 or 3 Kgy significantly (P ≤ .05) reduced yolk color regardless of the level of irradiation exposure implemented. This data indicates that gamma irradiation of intact raw eggs is effective in reducing (1 kGy) or eliminating (2 or more kGy) S. enteritidis contamination. However, each of the levels of irradiation used in the present experiments caused marked reduction of selected measures of egg quality.

  16. Elimination of coliforms and Salmonella spp. in sheep meat by gamma irradiation treatment

    PubMed Central

    Henriques, Luciana Salles Vasconcelos; da Costa Henry, Fábio; Barbosa, João Batista; Ladeira, Silvania Alves; de Faria Pereira, Silvia Menezes; da Silva Antonio, Isabela Maria; Teixeira, Gina Nunes; Martins, Meire Lelis Leal; de Carvalho Vital, Helio; dos Prazeres Rodrigues, Dália; dos Reis, Eliane Moura Falavina

    2013-01-01

    This study aimed at evaluating the bacteriological effects of the treatment of sheep meat contaminated with total coliforms, coliforms at 45 °C and Salmonella spp. by using irradiation at doses of 3 kGy and 5 kGy. Thirty sheep meat samples were collected from animals located in Rio de Janeiro State, Brazil, and then grouped in three lots including 10 samples: non-irradiated (control); irradiated with 3 kGy; and irradiated with 5 kGy. Exposure to gamma radiation in a 137Cs source-driven irradiating facility was perfomed at the Nuclear Defense Section of the Brazilian Army Technological Center (CTEx) in Rio de Janeiro. The samples were kept under freezing temperature (−18 °C) until the analyses, which occurred in two and four months after irradiation. The results were interpreted by comparison with the standards of the current legislation and demonstrated that non-irradiated samples were outside the parameters established by law for all groups of bacteria studied. Gamma irradiation was effective in inactivating those microorganisms at both doses tested and the optimal dose was achieved at 3 kGy. The results have shown not only the need for sanitary conditions improvements in slaughter and processing of sheep meat but also the irradiation effectiveness to eliminate coliform bacteria and Salmonella spp. PMID:24688504

  17. Elimination of coliforms and Salmonella spp. in sheep meat by gamma irradiation treatment.

    PubMed

    Henriques, Luciana Salles Vasconcelos; da Costa Henry, Fábio; Barbosa, João Batista; Ladeira, Silvania Alves; de Faria Pereira, Silvia Menezes; da Silva Antonio, Isabela Maria; Teixeira, Gina Nunes; Martins, Meire Lelis Leal; de Carvalho Vital, Helio; dos Prazeres Rodrigues, Dália; dos Reis, Eliane Moura Falavina

    2013-12-01

    This study aimed at evaluating the bacteriological effects of the treatment of sheep meat contaminated with total coliforms, coliforms at 45 °C and Salmonella spp. by using irradiation at doses of 3 kGy and 5 kGy. Thirty sheep meat samples were collected from animals located in Rio de Janeiro State, Brazil, and then grouped in three lots including 10 samples: non-irradiated (control); irradiated with 3 kGy; and irradiated with 5 kGy. Exposure to gamma radiation in a (137)Cs source-driven irradiating facility was performed at the Nuclear Defense Section of the Brazilian Army Technological Center (CTEx) in Rio de Janeiro. The samples were kept under freezing temperature (-18 °C) until the analyses, which occurred in two and four months after irradiation. The results were interpreted by comparison with the standards of the current legislation and demonstrated that non-irradiated samples were outside the parameters established by law for all groups of bacteria studied. Gamma irradiation was effective in inactivating those microorganisms at both doses tested and the optimal dose was achieved at 3 kGy. The results have shown not only the need for sanitary conditions improvements in slaughter and processing of sheep meat but also the irradiation effectiveness to eliminate coliform bacteria and Salmonella spp.

  18. Effect of mercerization and gamma irradiation on the dyeing behaviour of cotton using stilbene based direct dye

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz Ahmad; Adeel, Shahid; Fazal-ur-Rehman; Irshad, Misbah; Abbas, Muhammad

    2012-07-01

    The dyeing behaviour of mercerized and gamma irradiated cotton fabric using stilbene based direct dye has been investigated. The fabric was treated with different concentrations of alkali to optimize the mercerization. The optimum mercerized cotton fabric was irradiated to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature, time of dyeing, pH of dyeing solutions and salt concentration were optimized. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organization (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It was found that mercerized and irradiated cotton have not only improved the colour strength but enhanced the rating of fastness properties also.

  19. Effect of gamma irradiation on physicochemical properties of stored pigeon pea (Cajanus cajan) flour.

    PubMed

    Bamidele, Oluwaseun P; Akanbi, Charles T

    2013-09-01

    The effect of gamma irradiation at various doses (5, 10, 15, 20 kGy) was observed on pigeon pea flour stored for 3 months on proximate composition, functional properties, and peroxide value. Sensory evaluation was also carried out on bean cake (moinmoin) made from nonirradiated and irradiated pigeon pea flour. The results showed that stored gamma-irradiated samples had significantly lower (P < 0.05) value of protein and little or no effect on moisture content. There were slight decreases in crude fiber and ash content of the irradiated samples compared with the control sample. The result of functional properties of the irradiated flours showed slight increase in water absorption capacity, swelling capacity and bulk density. The peroxide value of crude oil increased significantly with dose increases for the period of storage. The sensory evaluation of moinmoin samples prepared from irradiated pigeon pea flour showed no significant difference from the moinmoin sample prepared from nonirradiated flour. It can be concluded that gamma irradiation can extend the shelf life of pigeon pea flour. PMID:24804044

  20. Effect of gamma irradiation on physicochemical properties of stored pigeon pea (Cajanus cajan) flour

    PubMed Central

    Bamidele, Oluwaseun P; Akanbi, Charles T

    2013-01-01

    The effect of gamma irradiation at various doses (5, 10, 15, 20 kGy) was observed on pigeon pea flour stored for 3 months on proximate composition, functional properties, and peroxide value. Sensory evaluation was also carried out on bean cake (moinmoin) made from nonirradiated and irradiated pigeon pea flour. The results showed that stored gamma-irradiated samples had significantly lower (P < 0.05) value of protein and little or no effect on moisture content. There were slight decreases in crude fiber and ash content of the irradiated samples compared with the control sample. The result of functional properties of the irradiated flours showed slight increase in water absorption capacity, swelling capacity and bulk density. The peroxide value of crude oil increased significantly with dose increases for the period of storage. The sensory evaluation of moinmoin samples prepared from irradiated pigeon pea flour showed no significant difference from the moinmoin sample prepared from nonirradiated flour. It can be concluded that gamma irradiation can extend the shelf life of pigeon pea flour. PMID:24804044

  1. Developmental inhibition of gamma irradiation on the peach fruit moth Carposina sasakii (Lepidoptera: Carposinidae)

    NASA Astrophysics Data System (ADS)

    Ryu, Jihoon; Ahn, Jun-Young; Sik Lee, Seung; Lee, Ju-Woon; Lee, Kyeong-Yeoll

    2015-01-01

    Ionizing irradiation is a useful technique for disinfestation under plant quarantine as well as post-harvest management. Effects of gamma irradiation treatment were tested on different developmental events of Carposina sasakii, which is a serious pest of various orchard crops. Apple fruits infested by C. sasakii were irradiated by gamma rays ranging from 0 to 300 Gy. Inhibition rates were determined on behavioral events related to development, including larval exit from apples, cocoon formation, adult eclosion, and oviposition. Failure rates of all these developmental events increased with increasing doses of irradiation. Rates of larval exit from apples and cocoon formation decreased to 13.2% and 1.7%, respectively, at 300 Gy. However, the adult eclosion rate decreased to 5.4% at 100 Gy and was completely inhibited at doses greater than 150 Gy. LD99 values for the inhibition of cocoon formation and adult emergence was estimated into 313.4 and 191.0 Gy. Furthermore, adults developed from irradiated larvae completely failed to lay eggs. Thus, irradiation of infested apples at doses of 200 Gy and higher completely inhibited the next generation of C. sasakii. Our results suggest that gamma irradiation treatment would be a promising technique for the control of C. sasakii.

  2. Effects of gamma and electron beam irradiation on the properties of calendered cord fabrics

    NASA Astrophysics Data System (ADS)

    Aytaç, Ayşe; Deniz, Veli; Şen, Murat; Hegazy, El-Sayed; Güven, Olgun

    2010-03-01

    The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing radiation. Ny 6 and Ny 66 calendered fabrics are more sensitive even at low doses. Therefore, the effects of high energy irradiation on tyre cords have to be taken into consideration during tyre design reinforced with particularly Ny fabrics if pre-vulcanization with high energy radiation is to be applied.

  3. Effect of gamma irradiation on physicochemical properties of stored pigeon pea (Cajanus cajan) flour.

    PubMed

    Bamidele, Oluwaseun P; Akanbi, Charles T

    2013-09-01

    The effect of gamma irradiation at various doses (5, 10, 15, 20 kGy) was observed on pigeon pea flour stored for 3 months on proximate composition, functional properties, and peroxide value. Sensory evaluation was also carried out on bean cake (moinmoin) made from nonirradiated and irradiated pigeon pea flour. The results showed that stored gamma-irradiated samples had significantly lower (P < 0.05) value of protein and little or no effect on moisture content. There were slight decreases in crude fiber and ash content of the irradiated samples compared with the control sample. The result of functional properties of the irradiated flours showed slight increase in water absorption capacity, swelling capacity and bulk density. The peroxide value of crude oil increased significantly with dose increases for the period of storage. The sensory evaluation of moinmoin samples prepared from irradiated pigeon pea flour showed no significant difference from the moinmoin sample prepared from nonirradiated flour. It can be concluded that gamma irradiation can extend the shelf life of pigeon pea flour.

  4. X-ray absorption studies of gamma irradiated Nd doped phosphate glass

    SciTech Connect

    Rai, V. N.; Rajput, Parasmani; Jha, S. N.; Bhattacharyya, D.

    2015-06-24

    This paper presents the X-ray absorption near edge structure (XANES) studies of Nd doped phosphate glasses before and after gamma irradiation. The intensity and location of L{sub III} edge white line peak of Nd changes depending on its concentration as well as on the ratio of O/Nd in the glass matrix. The decrease in the peak intensity of white line after gamma irradiation indicates towards reduction of Nd{sup 3+} to Nd{sup 2+} in the glass matrix, which increases with an increase in the doses of gamma irradiation. Similarity in the XANES spectra of Nd doped phosphate glasses and Nd{sub 2}O{sub 3} suggests that coordination geometry around Nd{sup 3+} in glass samples may be identical to that of Nd{sub 2}O{sub 3}.

  5. Effect of monopropylene glycol and gamma irradiation on Yarrowia lipolytica lipase stabilization.

    PubMed

    Alloue, W A M; Destain, J; Ongena, M; Blecker, C; Thonart, P

    2008-01-01

    This work investigated the effects of monopropylene glycol, protease inhibitor, and gamma irradiation on Yarrowia lipolytica lipase stability during storage. Enzyme liquid stabilization was achieved by addition of monopropylene glycol (MPG) at respective concentrations of 50, 75, and 90%, the protease inhibitors (P2714 and P8215) at 0.1%, and the gamma irradiation with 10kGy, 15kGy, and 25kGy doses. The results showed that monopropylene glycol limited the microorganism growth and decreased the enzymatic activity at high concentration (up to 50%), at two temperatures (20 and 4 degrees C). Enzyme stored at 20 degrees C lost its activity by 80% after two months. This loss was attributed to the protease's effect. At this temperature, the protease's activities have been limited by the specific inhibitors. The gamma irradiations improve microbial safety of liquid enzyme. PMID:18569869

  6. The effects of gamma irradiation on neutron displacement sensitivity of lateral PNP bipolar transistors

    NASA Astrophysics Data System (ADS)

    Wang, Chenhui; Chen, Wei; Liu, Yan; Jin, Xiaoming; Yang, Shanchao; Qi, Chao

    2016-09-01

    The effects of gamma irradiation on neutron displacement sensitivity of four types of lateral PNP bipolar transistors (LPNPs) with different neutral base widths, emitter widths and the doping concentrations of the epitaxial base region are studied. The physical mechanisms of the effects are explored by defect analysis using deep level transient spectroscopy (DLTS) techniques and numerical simulations of recombination process in the base region of the lateral PNP bipolar transistors, and are verified by the experiments on gate-controlled lateral PNP bipolar transistors (GCLPNPs) manufactured in the identical commercial bipolar process with different gate bias voltage. The results indicate that gamma irradiation increases neutron displacement damage sensitivity of lateral PNP bipolar transistors and the mechanism of this phenomenon is that positive charge induced by gamma irradiation enhances the recombination process in the defects induced by neutrons in the base region, leading to larger recombination component of base current and greater gain degradation.

  7. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Chen, C. Y.; Fu, M. J.; Tsai, C. Y.; Lin, F. H.; Chen, K. Y.

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe3O4 was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered.

  8. Physiological and molecular characterization of the enhanced salt tolerance induced by low-dose gamma irradiation in Arabidopsis seedlings

    SciTech Connect

    Qi, Wencai; Zhang, Liang; Xu, Hangbo; Wang, Lin; Jiao, Zhen

    2014-07-25

    Highlights: • 50-Gy gamma irradiation markedly promotes the seedling growth under salt stress in Arabidopsis. • The contents of H{sub 2}O{sub 2} and MDA are obviously reduced by low-dose gamma irradiation under salt stress. • Low-dose gamma irradiation stimulates the activities of antioxidant enzymes under salt stress. • Proline accumulation is required for the low-gamma-ray-induced salt tolerance. • Low gamma rays differentially regulate the expression of genes related to salt stress. - Abstract: It has been established that gamma rays at low doses stimulate the tolerance to salt stress in plants. However, our knowledge regarding the molecular mechanism underlying the enhanced salt tolerance remains limited. In this study, we found that 50-Gy gamma irradiation presented maximal beneficial effects on germination index and root length in response to salt stress in Arabidopsis seedlings. The contents of H{sub 2}O{sub 2} and MDA in irradiated seedlings under salt stress were significantly lower than those of controls. The activities of antioxidant enzymes and proline levels in the irradiated seedlings were markedly increased compared with the controls. Furthermore, transcriptional expression analysis of selected genes revealed that some components of salt stress signaling pathways were stimulated by low-dose gamma irradiation under salt stress. Our results suggest that gamma irradiation at low doses alleviates the salt stress probably by modulating the physiological responses as well as stimulating the stress signal transduction in Arabidopsis seedlings.

  9. Polymerization of calcium caseinates solutions induced by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Lacroix, M.; Jobin, M.; Mezgheni, E.; Srour, M.; Boileau, S.

    1998-06-01

    Solutions of calcium caseinate (5%) combined with propylene glycol (PG) or triethylene glycol(TEG) (0, 2.5% and 5%) and used for the development of edible films and coatings, were irradiated at doses between 0 to 128 kGy. Solutions were chromatographed through toyopearl HW 55F resin to observe the effect of irradiation on cross-link reactions. In unirradiated calcium caseinate solutions, two peaks could be observed (fractions 30 and 37) while samples irradiated at 64 kGy and 128 kGy showed one shifted peak at fraction 32 and 29 respectively. No effect of the plasticizers was observed. According to proteins standards of knowed molecular weights, the molecular weight of calcium caseinate increased approximately 10 times when irradiated at 128 kGy and 5 times when irradiated at 64 kGy. The physico-chemical properties of bio-films prepared with the irradiated solutions, demonstrated that tensile strength at break increased with increase of irradiation dose. A maximum dose was obtained at 16 kGy.

  10. A Mitochondria-Targeted Nitroxide/Hemigramicidin S Conjugate Protects Mouse Embryonic Cells Against Gamma Irradiation

    SciTech Connect

    Jiang Jianfei; Belikova, Natalia A.; Hoye, Adam T.; Zhao Qing; Epperly, Michael W.; Greenberger, Joel S.; Wipf, Peter; Kagan, Valerian E.

    2008-03-01

    Purpose: To evaluate the in vitro radioprotective effect of the mitochondria-targeted hemigramicidin S-conjugated 4-amino-2,2,6,6-tetramethyl-piperidine-N-oxyl (hemi-GS-TEMPO) 5-125 in {gamma}-irradiated mouse embryonic cells and adenovirus-12 SV40 hybrid virus transformed human bronchial epithelial cells BEAS-2B and explore the mechanisms involved in its radioprotective effect. Methods and Materials: Cells were incubated with 5-125 before (10 minutes) or after (1 hour) {gamma}-irradiation. Superoxide generation was determined by using dihydroethidium assay, and lipid oxidation was quantitated by using a fluorescence high-performance liquid chromatography-based Amplex Red assay. Apoptosis was characterized by evaluating the accumulation of cytochrome c in the cytosol and externalization of phosphatidylserine on the cell surface. Cell survival was measured by means of a clonogenic assay. Results: Treatment (before and after irradiation) of cells with 5-125 at low concentrations (5, 10, and 20 {mu}M) effectively suppressed {gamma}-irradiation-induced superoxide generation, cardiolipin oxidation, and delayed irradiation-induced apoptosis, evaluated by using cytochrome c release and phosphatidylserine externalization. Importantly, treatment with 5-125 increased the clonogenic survival rate of {gamma}-irradiated cells. In addition, 5-125 enhanced and prolonged {gamma}-irradiation-induced G{sub 2}/M phase arrest. Conclusions: Radioprotection/mitigation by hemi-GS-TEMPO likely is caused by its ability to act as an electron scavenger and prevent superoxide generation, attenuate cardiolipin oxidation in mitochondria, and hence prevent the release of proapoptotic factors from mitochondria. Other mechanisms, including cell-cycle arrest at the G{sub 2}/M phase, may contribute to the protection.

  11. Gamma-Weighted Discrete Ordinate Two-Stream Approximation for Computation of Domain Averaged Solar Irradiance

    NASA Technical Reports Server (NTRS)

    Kato, S.; Smith, G. L.; Barker, H. W.

    2001-01-01

    An algorithm is developed for the gamma-weighted discrete ordinate two-stream approximation that computes profiles of domain-averaged shortwave irradiances for horizontally inhomogeneous cloudy atmospheres. The algorithm assumes that frequency distributions of cloud optical depth at unresolved scales can be represented by a gamma distribution though it neglects net horizontal transport of radiation. This algorithm is an alternative to the one used in earlier studies that adopted the adding method. At present, only overcast cloudy layers are permitted.

  12. Effect of gamma and neutron irradiation on the mechanical properties of Spectralon™ porous PTFE

    DOE PAGESBeta

    Gourdin, William H.; Datte, Philip; Jensen, Wayne; Khater, Hesham; Pearson, Mark; Girard, Sylvain; Paillet, Philippe; Alozy, Eric

    2016-07-21

    Here, we establish a correspondence between the mechanical properties (maximum load and failure elongation) of Spectralon™ porous PTFE irradiated with 14 MeV neutrons and 1.17 and 1.33 MeV gammas from a cobalt-60 source. From this correspondence we infer that the effects of neutrons and gammas on this material are approximately equivalent for a given absorbed dose.

  13. Biodegradable zein-based films: influence of gamma-irradiation on structural and functional properties.

    PubMed

    Soliman, Emad A; Mohy Eldin, Mohamed S; Furuta, Masakazu

    2009-03-25

    Zein, a predominant corn protein, is an alcohol-soluble protein extracted from corn and is characterized by unique film-forming properties. The characteristic brittleness of zein diminishes its usefulness as a structural material. The objective of this work was to study the effect of gamma-irradiation on improving the performance of zein films in packaging applications. This goal has been achieved by irradiating zein film-forming solutions with various doses of gamma-rays, namely, 10, 20, 30, and 40 kGy at dose rate of 10.5 kGy/h, using a Co(60) gamma-radiation source. The impact of radiation process on the structural properties has been explored through far-UV CD spectral analysis and scanning electron microscopy. Additionally, viscosity changes that reflect the effect of radiation treatment on degradation and/or cross-linking of protein chains have been measured. However, improvements in the performance of zein films as packaging materials that can be accomplished by radiation treatment have been investigated via monitoring of the color, surface density, roughness, mechanical properties (tensile strength and elongation percentage), water uptake, and water barrier properties. The results indicated that gamma-irradiation treatment of the film-forming solution can be used to improve the water barrier properties, as well as color and appearance of the zein films. Moreover, a sterilization effect is considered to be an additional advantage for applying gamma- irradiation. PMID:19292471

  14. Physical properties of gamma irradiated poly(vinyl alcohol) hydrogel preparations

    NASA Astrophysics Data System (ADS)

    Mondino, A. V.; González, M. E.; Romero, G. R.; Smolko, E. E.

    1999-08-01

    Poly(vinyl alcohol) films from 15% w/w aqueous solutions and a thickness of 0.2 mm were selected for this study. The films were first humidified and then acetalized and/or gamma irradiated. Then, their physical properties were tested. Tensile strength of the hydrogel films reached its maximum value in samples irradiated with a 80 kGy dose, in the case of acetalized films the dose necessary for maximum tensile strength was only 40 kGy. The combination of acetalization with formaldehyde and gamma radiation produced an elastic hydrogel with good tackiness and excellent mechanical and thermal strength.

  15. Facility for gamma irradiations of cultured cells at low dose rates: design, physical characteristics and functioning.

    PubMed

    Esposito, Giuseppe; Anello, Pasquale; Pecchia, Ilaria; Tabocchini, Maria Antonella; Campa, Alessandro

    2016-09-01

    We describe a low dose/dose rate gamma irradiation facility (called LIBIS) for in vitro biological systems, for the exposure, inside a CO2 cell culture incubator, of cells at a dose rate ranging from few μGy/h to some tens of mGy/h. Three different (137)Cs sources are used, depending on the desired dose rate. The sample is irradiated with a gamma ray beam with a dose rate uniformity of at least 92% and a percentage of primary 662keV photons greater than 80%. LIBIS complies with high safety standards. PMID:27423023

  16. Spirogyra varians mutant generated by high dose gamma-irradiation shows increased antioxidant properties

    NASA Astrophysics Data System (ADS)

    Lee, Hak-Jyung; Yoon, Minchul; Sung, Nak-Yun; Choi, Jong-il

    2012-08-01

    The aim of this study was to evaluate the antioxidant properties of a Spirogyra varians mutant (Mut) produced by gamma irradiation. Methanol extracts were prepared from Spirogyra varians wild-type and Mut plants, and their antioxidant activities and total phenolic content (TPC) were determined. Antioxidant parameters, including the 2-diphenyl-1-picrylhydrazyl radical-scavenging activity and ferric-reducing/antioxidant power, were higher in the Mut extract. Moreover, the TPC level was higher (P<0.05) in the Mut methanol extract. Therefore, these results suggest that gamma irradiation-induced S. varians Mut has superior antioxidant properties.

  17. Gamma irradiator dose mapping simulation using the MCNP code and benchmarking with dosimetry.

    PubMed

    Sohrabpour, M; Hassanzadeh, M; Shahriari, M; Sharifzadeh, M

    2002-10-01

    The Monte Carlo transport code, MCNP, has been applied in simulating dose rate distribution in the IR-136 gamma irradiator system. Isodose curves, cumulative dose values, and system design data such as throughputs, over-dose-ratios, and efficiencies have been simulated as functions of product density. Simulated isodose curves, and cumulative dose values were compared with dosimetry values obtained using polymethyle-methacrylate, Fricke, ethanol-chlorobenzene, and potassium dichromate dosimeters. The produced system design data were also found to agree quite favorably with those of the system manufacturer's data. MCNP has thus been found to be an effective transport code for handling of various dose mapping excercises for gamma irradiators.

  18. A feasibility study of gamma irradiation on Thailand frozen shrimps ( PENEAUS MONODON)

    NASA Astrophysics Data System (ADS)

    Lacroix, M. L.; Charbonneau, R.; Jobin, M.; Thibault, C.; Nouchpramool, K.; Charoen, S.; Gagnon, M.

    1995-02-01

    Two lots of frozen precooked shrimps from Thaïland "PENAEUS MONODON" Black tiger variety were irradiated at 1.8 to 3.6 kGy. This way, it was hoped to compare the effects of gamma irradiation on the microbiological quality and the organoleptic properties of frozen precooked shrimps after transportation from Thailand to Canada. The results indicated that the extension of shelf-life based on mesophiles content was from 33 days for the control to more than 47 days for the irradiated shrimps stored at 3 ± 1 °C. The results of sensory evaluation gave slightly fresher odor for the control than the irradiated shrimps. On day one, this effect was more apparent. The results of hedonic tests showed that the irradiated shrimps were acceptable during storage. In conclusion, the results demonstrate that the combined treatments (freezing plus irradiation) of precooked shrimps are useful for increasing the storage life of shrimps without affecting consumer acceptability.

  19. Enhancement of enzymatic hydrolysis of wheat straw by gamma irradiation-alkaline pretreatment

    NASA Astrophysics Data System (ADS)

    Yin, Yanan; Wang, Jianlong

    2016-06-01

    Pretreatment of wheat straw with gamma irradiation and NaOH was performed to enhance the enzymatic hydrolysis of wheat straw for production of reducing sugar. The results showed that the irradiation of wheat straw at 50 kGy decreased the yield of reducing sugar, however, the reducing sugar yield increased with increasing dose from 50 kGy to 400 kGy. The irradiation of wheat straw at 100 kGy can significantly decrease NaOH consumption and treatment time. The reducing sugar yield could reach 72.67% after irradiation at 100 kGy and 2% NaOH treatment for 1 h. The combined pretreatment of wheat straw by gamma radiation and NaOH immersion can increase the solubilization of hemicellulose and lignin as well as the accessible surface area for enzyme molecules.

  20. Characterization of LWRS Hybrid SiC-CMC-Zircaloy-4 Fuel Cladding after Gamma Irradiation

    SciTech Connect

    Isabella J van Rooyen

    2012-09-01

    The purpose of the gamma irradiation tests conducted at the Idaho National Laboratory (INL) was to obtain a better understanding of chemical interactions and potential changes in microstructural properties of a mock-up hybrid nuclear fuel cladding rodlet design (unfueled) in a simulated PWR water environment under irradiation conditions. The hybrid fuel rodlet design is being investigated under the Light Water Reactor Sustainability (LWRS) program for further development and testing of one of the possible advanced LWR nuclear fuel cladding designs. The gamma irradiation tests were performed in preparation for neutron irradiation tests planned for a silicon carbide (SiC) ceramic matrix composite (CMC) zircaloy-4 (Zr-4) hybrid fuel rodlet that may be tested in the INL Advanced Test Reactor (ATR) if the design is selected for further development and testing

  1. Modification of uterotropic effect of estrogens by whole-body gamma-irradiation.

    PubMed

    Bershtein, L M; Tsyrlina, E V; Poroshina, T E; Gamayunova, V B; Solntseva, O S; Kalinina, N M; Ivanov, S D; Kovalenko, I G; Vasil'ev, D A

    2001-08-01

    The effect of gamma-irradiation on the realization of the effects of estrogens was studied on rats treated with N-acetylcysteine, vitamins C and E, melatonin, and carnosine or subjected to forced swimming in a training mode. Irradiation (0.2 Gy) in combination with estrogens and without correction therapy induced genotoxic changes in the uterus, while irradiation in a higher dose (2 Gy) predominantly potentiated the hormonal effect of estrogens. Correction of the revealed abnormalities was achieved mainly with carnosine. The peculiarities of "estrogen toggle (re-targeting) effect" under the effect of gamma-irradiation and its elimination differed from those induced by ethanol intake or tobacco smoking, which is important for understanding the mechanisms of hormone-induced carcinogenesis.

  2. Sterilization of ready-to-cook Bibimbap by combined treatment with gamma irradiation for space food

    NASA Astrophysics Data System (ADS)

    Park, Jae-Nam; Song, Beom-Seok; Kim, Jae-Hun; Choi, Jong-il; Sung, Nak-Yun; Han, In-Jun; Lee, Ju-Woon

    2012-08-01

    Bibimbap, Korean traditional cooked rice mixed with various kinds of vegetables, together with mushrooms and a ground meat, and seasoned with red pepper paste, was developed as a ready-to-cook food by combined treatment with irradiation for the use in space. By gamma irradiation of 25 kGy, the total aerobic bacteria of Bibimbap that was initial by 6.3 log CFU/g decreased to below detection limit, but its sensory qualities were drastically decreased. To enhance the sensory quality, the effects of antioxidant in Bibimbap were evaluated. A treatment with 0.1% of vitamin C, vacuum packaging and gamma-irradiated at 25 kGy and -70 °C showed higher sensory scores than only the irradiation process. This result indicates that the radiation technology may be useful to produce a variety of space foods with high quality of taste and flavor, when combined with other methods.

  3. Chemical composition and lipoxygenase activity in soybeans (Glycine max L. Merr.) submitted to gamma irradiation

    NASA Astrophysics Data System (ADS)

    Barros, Érica Amanda de; Broetto, Fernando; Bressan, Dayanne F.; Sartori, Maria M. P.; Costa, Vladimir E.

    2014-05-01

    Soybeans are an important food due to their functional and nutritional characteristics. However, consumption by western populations is limited by the astringent taste of soybeans and their derivatives which results from the action of lipoxygenase, an enzyme activated during product processing. The aim of this study was to evaluate the effect of gamma irradiation on the chemical composition and specific activity of lipoxygenase in different soybean cultivars. Soybeans were stored in plastic bags and irradiated with doses of 2.5, 5 and 10 kGy. The chemical composition (moisture, protein, lipids, ashes, crude fiber, and carbohydrates) and lipoxygenase specific activity were determined for each sample. Gamma irradiation induced a small increase of protein and lipid content in some soybean cultivars, which did not exceed the highest content of 5% and 26%, respectively, when compared to control. Lipoxygenase specific activity decreased in the three cultivars with increasing gamma irradiation dose. In conclusion, the gamma irradiation doses used are suitable to inactivate part of lipoxygenase while not causing expressive changes in the chemical composition of the cultivars studied.

  4. Effect of gamma irradiation on the properties of plastic bottle sheet

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay; Ali, Yasir; Sonkawade, R. G.; Dhaliwal, A. S.

    2012-09-01

    In this article, the effects of gamma irradiation on the optical and structural properties of plastic bottle sheets have been studied. Bottle sheets were exposed with 1.25 MeV 60Co γ-ray's source at various dose levels within the range from 0 to 670 kGy. The changes so induced were analyzed by using UV-Vis and X-ray diffraction spectroscopy. UV-Vis spectra show the peaks, their shifting and broadening as a result of gamma irradiation. With increasing γ-dose, the values of the direct and indirect band gap are found to be decreased. These results are in good agreement with the corresponding results published previously for polyethylene terephthalate polymer. We also calculated numbers of carbon atoms per conjugation length. The X-ray diffraction spectra exhibited an increase in peak intensity after gamma irradiation. Furthermore, the percentage crystallinity and crystallite size for pristine and irradiated sample have been calculated. It has been found that both crystallinity and crystallite size increase due to irradiation. In addition, interchain distances, micro strain, inter planar distance, dislocation density and distortion parameters were calculated. The analysis revealed there is the significant decrease in micro strain, dislocation density and distortion parameters with an increase of gamma dose, which is in line with the crystallinity calculation. Moreover, Interchain and Interplanar distances were marginally changed. These results demonstrated the applicability of sheets as a cost-effective dosimeter.

  5. Effect of gamma irradiation on physical characteristics of Jordanian durum wheat and quality of semolina and lasagna products

    NASA Astrophysics Data System (ADS)

    Azzeh, F. S.; Amr, A. S.

    2009-09-01

    This study was conducted to determine the effect of using varying gamma irradiation doses on the physiochemical and rheological properties of semolina and its products. Ash, protein and water content were not influenced with gamma irradiation, while falling number and fungi counts decreased with increasing irradiation dose. Irradiation adversely affected wet gluten at 5 kGy dose. Dough stability was deteriorated vigorously with increasing irradiation dose. Sensory evaluation showed that lasagna produced from 0.25- and 1 kGy-irradiated semolina did not show any significant differences as compared with the control sample.

  6. Detection of gamma irradiated pepper and papain by chemiluminescence

    NASA Astrophysics Data System (ADS)

    Sattar, Abdus; Delincée, H.; Diehl, J. F.

    Chemiluminescence (CL) measurements of black pepper and of papain using luminol and lucigenin reactions were studied. Effects of grinding, irradiation (5-20 kGy) and particle size (750-140 μm) on CL of pepper, and of irradiation (10-30 kGy) on CL of papain, were investigated. All the tested treatments affected the luminescence response in both the luminol and lucigenin reactions; however, the pattern of changes in each case, was inconsistent. Optimum pepper size for maximum luminescence was 560 μm, and optimum irradiation doses were >15 kGy for pepper and >20 kGy for papain. Chemiluminescence may possibly be used as an indicator or irradiation treatment for pepper and papain at a dose of 10 kGy or higher, but further research is needed to establish the reliability of this method.

  7. Polymerization of vinyl acetate in bulk and emulsion by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Mesquita, Andrea C.; Mori, Manoel N.; Andrade e Silva, Leonardo G.

    2004-09-01

    The vinyl acetate polymerization to produce poly(vinyl acetate) was carried out in bulk and emulsion using a 60Co gamma irradiator Gammacell-220 type. The irradiation was carried out in a dose rate of 5.25 and 5.30 kGy/h, respectively. The polymers obtained were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC) and gel permeation chromatography (GPC). Tests of density, hardness and Vicat softening temperature were carried out.

  8. The morphological changes of Ascaris lumbricoides ova in sewage sludge water treated by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Shamma, M.; Al-Adawi, M. A.

    2002-10-01

    Untreated wastewater sampled from Damascus sewage water treatment plant containing nematode Ascaris lumbricoides ova were treated using gamma irradiation (doses between 1.5 and 8 kGy), immediately after irradiation the morphological and developmental status of eggs was examined microscopically. Major morphological changes of the contents of the eggs were detected. These eggs were incubated for 8 weeks, after this period no larvae "inside the eggs" were observed. Thus the morphological changes can be used as a viable parameter.

  9. Electron spin resonance of gamma-irradiated poly/ethylene 2,6-naphthalene dicarboxylate/.

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Pezdirtz, G. F.

    1971-01-01

    The two types of radicals trapped in gamma-irradiated PEN 2,6 are identified by ESR as - O - CH - CH2 - O - (radical I) and a radical located on the naphthalene ring (radical II). The concentrations of the radicals in the gross polyer are 10 to 20% of I and 80 to 90% of II. Similar trapped radicals are established in beta-irradiated PET, a structurally related polymer.

  10. Feasibility of sterilizing traditional Chinese medicines by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Fang, Xingwang; Wu, Jilan

    1998-06-01

    The feasibility of sterilizing traditional Chinese medicine (TCMs) by γ-irradiation has been systematically evaluated by the biological, toxicological and physicochemical tests on irradiated hundreds of TCMs. Those TCMs investigated in general show no significant biological or toxicological changes after irradiation, yet physicochemical changes are detectable in some irradiated TCMs, and water in TCMs enhances the effects. Those results obtained from radiolysis of some major effective components of TCMs in aqueous or ethanolic solutions reveal that the site selection of radiolytically generated radicals follows the example of simple compounds with same function groups. Wholesomeness and chemical clearance present a bright future to sterilizing TCMs by γ irradiation, however, some important measures and steps should be adopted: (1) The producers must strictly execute manufacturing procedure to reduce microbiological contamination thus lower the applied dose for sterilization which is recommended to be controlled under 5, 7 or 10 kGy, 10 kGy for dry herb, 7 kGy for herbal medicine and 5 kGy for some special herbal medicine; (2) Herb to be sterilized by γ-irradiation should exist in possible dry state; (3) Powder TCMs is recommended to mix with honey forming bolus, which can minimize the decomposition of herb.

  11. Antibacterial Activity of Gamma-irradiated Chitosan Against Denitrifying Bacteria

    NASA Astrophysics Data System (ADS)

    Vilcáez, Javier; Watanabe, Tomohide

    2010-11-01

    In order to find an environmentally benign substitute to hazardous inhibitory agents, the inhibitory effect of γ-irradiated chitosans against a mixed culture of denitrifying bacteria was experimentally evaluated. Unlike other studies using pure aerobic cultures, the observed effect was not a complete inhibition but a transient inhibition reflected by prolonged lag phases and reduced growth rates. Raw chitosan under acid conditions (pH 6.3) exerted the strongest inhibition followed by the 100 kGy and 500 kGy irradiated chitosans respectively. Therefore because the molecular weight of chitosan decreases with the degree of γ-irradiation, the inhibitory properties of chitosan due to its high molecular weight were more relevant than the inhibitory properties gained due to the modification of the surface charge and/or chemical structure by γ-irradiation. High dosage of γ-irradiated appeared to increase the growth of mixed denitrifying bacteria in acid pH media. However, in neutral pH media, high dosage of γ-irradiation appeared to enhance the inhibitory effect of chitosan.

  12. Restricting the ageing degradation of the mechanical properties of gamma irradiated UHMWPE using MWCNTs.

    PubMed

    Rama Sreekanth, P S; Kanagaraj, S

    2013-05-01

    Property degradation of the medical grade polymers after gamma irradiation is the primary concern that limits longevity of them. Though the conventional antioxidant material helps to reduce the degradation but it limits the degree of crosslinking of the polymer. The objective of the present work is to study the influence of multi walled carbon nanotubes (MWCNTs) on restricting the degradation of mechanical properties of medical grade ultra high molecular weight polyethylene (UHMWPE) after its irradiation. UHMWPE was reinforced by chemically treated MWCNTs at different concentrations such as 0.5, 1.0, 1.5, and 2.0 wt%. The test samples were then subjected to Co⁶⁰ gamma irradiation with an integral dose of 25, 50, 75 and 100 kGy in air. The mechanical properties of irradiated samples were evaluated within 10 days, 60 and 120 days after irradiation. It was observed that the mechanical properties of virgin UHMWPE and nanocomposites were enhanced immediately after irradiation but they were found to be reduced at later stages. It was also observed that the presence of MWCNTs limited the ageing degradation of the mechanical properties of UHMWPE. Raman spectroscopic and TEM studies confirmed the formation of irradiation induced defects on the MWCNTs. Electron spin resonance studies showed that the relative radical intensity of virgin UHWMPE was reduced significantly with an increase of MWCNTs concentration confirming the radical scavenging ability of them. It is concluded that MWCNTs restricted the ageing degradation of irradiated UHMWPE.

  13. Synergistic effect of the combined treatment with gamma irradiation and sodium dichloroisocyanurate to control gray mold (Botrytis cinerea) on paprika

    NASA Astrophysics Data System (ADS)

    Yoon, Minchul; Jung, Koo; Lee, Kwang-Youll; Jeong, Je-Yong; Lee, Ju-Woon; Park, Hae-Jun

    2014-05-01

    Gray mold (Botrytis cinerea) is one of the most major fungal pathogens in paprika. Generally, gamma irradiation over 1 kGy is effective for the control of fungal pathogens; however, a significant change in fruit quality (physical properties) on paprika was shown from gamma irradiation at over 0.6 kGy (p<0.05). Therefore, in this study, the synergistic disinfection effect of the combined treatment with gamma irradiation and sodium dichloroisocyanurate (NaDCC) was investigated to reduce the gamma irradiation dose. In an artificial inoculation experiment of B. cinerea isolated from naturally-infected postharvest paprika, fungal symptoms were observed in the stem and exocarp of paprika after conidial inoculation. From the sensitivity of gamma irradiation and NaDCC, B. cinerea conidia were fully inactivated by 4 kGy of gamma irradiation (D10 value 0.99 kGy), and were fully inactivated by 50 ppm NaDCC treatment. The fungal symptoms were not detected by the dose-dependent gamma irradiation (>4 kGy) and NaDCC (>50 ppm). As a result of the combined treatment of gamma irradiation and NaDCC, the D10 value was significantly reduced by 1.06, 0.88, 0.77, and 0.58 kGy (p<0.05). Moreover, fungal symptoms were more significantly reduced in combined treatment groups (gamma irradiation and NaDCC) than single treatment groups (gamma irradiation or NaDCC). These results suggest that combined treatment with irradiation and NaDCC treatment can be applied to preserve quality of postharvest paprika or other fruits.

  14. Biochemical composition and antioxidant activities of Arthrospira (Spirulina) platensis in response to gamma irradiation.

    PubMed

    Shabana, Effat Fahmy; Gabr, Mahmoud Ali; Moussa, Helal Ragab; El-Shaer, Enas Ali; Ismaiel, Mostafa M S

    2017-01-01

    Arthrospira (Spirulina) platensis is a blue-green alga, rich with bioactive components and nutrients. To evaluate effect of gamma irradiation, A. platensis was exposed to different doses of 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5kGy. The data showed that the phenolic and proline contents significantly increased with the increase of gamma irradiation doses up to 2.0kGy, above which a reduction was observed. The soluble proteins and malondialdehyde (MDA) contents were stimulated by all tested irradiation doses. Furthermore, the vitamins (A, K and B group) and mineral contents (N, P, Na, K, Ca, Mg and Fe) were stimulated by the irradiation doses compared with the control. The activities of some N-assimilating and antioxidant enzymes were significantly increased with the irradiation doses up to 2.0kGy. This study suggests the possible use of gamma irradiation as a stimulatory agent to raise the nutritive value and antioxidant activity of A. platensis. PMID:27507509

  15. Inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in black pepper and red pepper by gamma irradiation.

    PubMed

    Song, Won-Jae; Sung, Hye-Jung; Kim, Sung-Youn; Kim, Kwang-Pyo; Ryu, Sangryeol; Kang, Dong-Hyun

    2014-02-17

    This study evaluated the efficacy of gamma irradiation to inactivate foodborne pathogens in black pepper (Piper nigrum) and red pepper (dried Capsicum annuum). Black pepper and red pepper inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium were subjected to gamma irradiation in the range of 0, 1, 2, 3 and 5 kGy, and color change was evaluated after treatment. Pathogen populations decreased with increasing treatment doses. A gamma irradiation dose of 5 kGy decreased E. coli O157:H7 and S. Typhimurium populations >4.4 to >5.2 log CFU/g in black pepper without causing color change. Similarly, 5 kGy of gamma irradiation yielded reduction of 3.8 to >5.2 log CFU/g for E. coli O157:H7 and S. Typhimurium in red pepper. During gamma irradiation treatment, L*, a* and b* values of red pepper were not significantly changed except for 297 μm to 420 μm size red pepper treated with 5 kGy of gamma irradiation. Based on the D-value of pathogens in black pepper and red pepper, S. Typhimurium showed more resistant to gamma irradiation than did E. coli O157:H7. These results show that gamma irradiation has potential as a non-thermal process for inactivating foodborne pathogens in spices with minimal color changes.

  16. Mossbauer Spectroscopic Study of Gamma Irradiation on the Structural Properties of Hematite, Magnetite and Limonite Concrete for Nuclear Reactor Shielding

    NASA Astrophysics Data System (ADS)

    Eissa, N. A.; Kany, M. S. I.; Mohamed, A. S.; Sallam, A. A.; El Fouly, M. H.

    1998-12-01

    This work investigate the effect of gamma irradiation on a heavy type of concrete, constructed for nuclear reactor shield. The effect of gamma irradiation was studied after annealing the concrete samples at 300°C for 24 hours in air.

  17. Gamma-irradiated bacterial preparation having anti-tumor activity

    DOEpatents

    Vass, Arpad A.; Tyndall, Richard L.; Terzaghi-Howe, Peggy

    1999-01-01

    A bacterial preparation from Pseudomonas species isolated #15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

  18. Gamma irradiation effects in programmable read only memories

    NASA Astrophysics Data System (ADS)

    Vujisic, M.; Osmokrovic, P.; Loncar, B.

    2007-09-01

    This paper examines the reliability of commercial off the shelf (COTS) erasable programmable read only memory (EPROM) and electrically erasable programmable read only memory (EEPROM) components exposed to gamma radiation. Results obtained for 64 KB EPROM (NM27C512) and 16 KB EEPROM (M24128) components provide evidence that EPROMs have greater radiation hardness than EEPROMs. Moreover, the changes in EPROMs are reversible, and after erasure and reprogramming all EPROM components restore their functionality. On the other hand, changes in EEPROMs are irreversible. The obtained results are analysed and interpreted on the basis of gamma ray interaction with the oxide layer.

  19. Gamma-irradiated bacterial preparation having anti-tumor activity

    SciTech Connect

    Vass, A.A.; Tyndall, R.L.; Terzaghi-Howe, P.

    1999-11-16

    This application describes a bacterial preparation from Pseudomonas species isolated {number{underscore}sign}15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

  20. Effects of Platinum Nanocolloid in Combination with Gamma Irradiation on Normal Human Esophageal Epithelial Cells.

    PubMed

    Li, Qiang; Tanaka, Yoshiharu; Saitoh, Yasukazu; Miwa, Nobuhiko

    2016-05-01

    Our previous study demonstrated that platinum nanocolloid (Pt-nc), combined with lower-dose gamma irradiation at 3, 5, and 7 Gy significantly decreased proliferation and accelerated apoptosis of the human esophageal squamous cell carcinoma-derived cell line KYSE-70. The aim of the present study was to determine, under the same conditions as our previous study where gamma rays combined with Pt-nc were carcinostatic to KYSE-70 cells, if we could induce a radioprotective or the radiation-sensitizing effect on the human normal esophageal epithelial cells (HEEpiC). HEEpiC were treated with various Pt-nc concentrations and then irradiated with various gamma-ray doses. The proliferative status of HEEpiC was evaluated using trypan blue dye-exclusion and WST-8 assays. The cellular and nucleic morphological features were determined using crystal violet and Hoechst 33342 stainings, respectively. The intracellular level of reactive oxygen species (ROS) in HEEpiC was evaluated with a nitro blue tetrazolium (NBT) assay. The apoptotic status was detected with caspase-3, Bax, and Bcl-2 by Western blotting. Either Pt-nc or gamma irradiation could inhibit the growth of HEEpiC; however, their combined use exerted a significant proliferation-inhibitory effect in a Pt-nc dose-dependent manner than gamma irradiation alone. Pt-nc resulted in radiation sensitization rather than radiation protection on HEEpiC in vitro similar to KYSE-70 cells, when Pt-nc was administrated alone or combined with gamma irradiation. Thus, Pt-nc has an inhibitory effect on cell proliferation, a facilitative effect on apoptosis, and a certain degree of toxicity against HEEpiC. PMID:27483929

  1. Effects of Platinum Nanocolloid in Combination with Gamma Irradiation on Normal Human Esophageal Epithelial Cells.

    PubMed

    Li, Qiang; Tanaka, Yoshiharu; Saitoh, Yasukazu; Miwa, Nobuhiko

    2016-05-01

    Our previous study demonstrated that platinum nanocolloid (Pt-nc), combined with lower-dose gamma irradiation at 3, 5, and 7 Gy significantly decreased proliferation and accelerated apoptosis of the human esophageal squamous cell carcinoma-derived cell line KYSE-70. The aim of the present study was to determine, under the same conditions as our previous study where gamma rays combined with Pt-nc were carcinostatic to KYSE-70 cells, if we could induce a radioprotective or the radiation-sensitizing effect on the human normal esophageal epithelial cells (HEEpiC). HEEpiC were treated with various Pt-nc concentrations and then irradiated with various gamma-ray doses. The proliferative status of HEEpiC was evaluated using trypan blue dye-exclusion and WST-8 assays. The cellular and nucleic morphological features were determined using crystal violet and Hoechst 33342 stainings, respectively. The intracellular level of reactive oxygen species (ROS) in HEEpiC was evaluated with a nitro blue tetrazolium (NBT) assay. The apoptotic status was detected with caspase-3, Bax, and Bcl-2 by Western blotting. Either Pt-nc or gamma irradiation could inhibit the growth of HEEpiC; however, their combined use exerted a significant proliferation-inhibitory effect in a Pt-nc dose-dependent manner than gamma irradiation alone. Pt-nc resulted in radiation sensitization rather than radiation protection on HEEpiC in vitro similar to KYSE-70 cells, when Pt-nc was administrated alone or combined with gamma irradiation. Thus, Pt-nc has an inhibitory effect on cell proliferation, a facilitative effect on apoptosis, and a certain degree of toxicity against HEEpiC.

  2. Effects of gamma-irradiation and air annealing on Yb-doped Y3Al5O12 single crystal.

    PubMed

    Zeng, Xionghui; Xu, Xiaodong; Wang, Xiaodan; Zhao, Zhiwei; Zhao, Guangjun; Xu, Jun

    2008-03-01

    The effects of gamma-irradiation on the air-annealed 10at.% Yb:Y(3)Al(5)O(12) (YAG) and air annealing on the gamma-irradiated 10at.% Yb:YAG have been studied by the difference absorption spectra before and after treatment. The gamma-irradiation and air annealing led to opposite changes of the absorption properties of the Yb:YAG crystal. After air annealing, the gamma-irradiation induced centers were totally removed and the concentration of Fe(3+) and Yb(3+) were lightly increased. For the first time, the gamma-irradiation induced valence changes between Yb(3+) and Yb(2+) ions in Yb:YAG crystals have been observed.

  3. Change in Ion Beam Induced Current from Si Metal-Oxide-Semiconductor Capacitors after Gamma-Ray Irradiation

    SciTech Connect

    Ohshima, T.; Onoda, S.; Hirao, T.; Takahashi, Y.; Vizkelethy, G.; Doyle, B. L.

    2009-03-10

    To investigate the effects of gamma-ray irradiation on transient current induced in MOS capacitors by heavy ion incidence, Si MOS capacitors were irradiated with gamma-rays up to 60.9 kGy(SiO2). The change in Transient Ion Beam Induced Current (TIBIC) signals due to gamma-ray irradiation was investigated using 15 MeV-oxygen ion microbeams. After gamma-ray irradiation, the peak current of the TIBIC signal vs. bias voltage curve shifted toward negative voltages. This shift can be interpreted in terms of the charge trapped in the oxide. In this dose range, no significant effects of the interface traps induced by gamma-ray irradiation on the TIBIC signals were observed.

  4. [Use of the EC 1010 computer to calculate dosimetric parameters for irradiation procedures in gamma teletherapy].

    PubMed

    Likhovetskaia, R B; Dvorova, E V

    1983-05-01

    An ever growing flow of patients requires a good deal of time for the planning of irradiation procedures of patients and causes errors during manual calculations. A small-size computer EC 1010 is proposed for the calculation of dosimetric parameters of irradiation procedures on gamma-beam therapeutic units. A specially designed program is intended for the calculation of dosimetric parameters for different methods of moving and static irradiation taking into account tissue heterogeneity: multifield static irradiation, multizone rotation irradiation, irradiation using dose field forming devices (V-shaped filters, edge blocks, a grid diaphragm). In addition to the main calculated values, the listing contains in a suitable form all necessary information: the patient's name, date of calculation, a unit type for irradiation, irradiation procedure parameters. The computation of output parameters according to each preset program of irradiation takes no more than 1 min. The use of the computer EC 1010 for the calculation of dosimetric parameters of irradiation procedures gives an opportunity to considerably reduce calculation time, to avoid possible errors and to simplify the drawing up of documents.

  5. Beneficial effect of gamma irradiation on the N-deacetylation of chitin to form chitosan

    NASA Astrophysics Data System (ADS)

    Tahtat, Djamel; Uzun, Cengiz; Mahlous, Mohamed; Güven, Olgun

    2007-12-01

    The effect of gamma irradiation on the N-deacetylation of chitin to form chitosan was studied. Chitin from crab shells was irradiated up to 20 kGy and N-deacetylated in aqueous NaOH solution (40% and 60% w/w) at 60 and 100 °C for 60 min. The degree of N-deacetylation (DD) of non-irradiated and irradiated samples was determined by IR-band ratio method. It was found that higher extent of N-deacetylation was achieved for the chitin samples irradiated up to 20 kGy doses as compared to non-irradiated chitin. The DD values of chitin, prepared from non-irradiated and 20 kGy irradiated chitins by N-deacetylation at 60 °C with 40% NaOH for 60 min, were found to be 38% and 60%, respectively. The increase in DD by irradiation was interpreted as a result of reduction in molecular weight of chitin. Low dose irradiation of chitin has provided the possibility of its N-deacetylation into chitosan at much milder reaction conditions.

  6. Effects of gamma irradiation on chemical, microbial quality and shelf life of shrimp

    NASA Astrophysics Data System (ADS)

    Hocaoğlu, Aslı; Sükrü Demirci, Ahmet; Gümüs, Tuncay; Demirci, Mehmet

    2012-12-01

    In the present study the combined effect of gamma irradiation (1, 3 and 5 kGy) and storage at two temperatures: refrigeration (+4 °C) and frozen (-18 °C), on the shelf-life extension of fresh shrimp meat was investigated. The study was based on microbiological and physicochemical changes occuring in the shrimp samples. Total volatile base nitrogen values and trimethylamine values for irradiated shrimp samples were significantly lower than non-irradiated samples at both storage temperatures, and the rate of decrease was more pronounced in samples irradiated at the higher dose (p<0.05). Thiobarbituric acid values for irradiated shrimp samples were significantly higher than non-irradiated samples at both storage temperatures (p<0.05). pH values of shrimp samples were affected significantly by both irradiating dose and storage temperatures (p<0.05). Microbial counts for non-irradiated shrimp samples were higher than the respective irradiated samples at both storage temperatures (p<0.05). The results revealed that irradiation at high dose (5 kGy) might enhance lipid oxidation, although the growth of microorganisms and protein oxidation was inhibited.

  7. Effects of gamma irradiation on the yields of volatile extracts of Angelica gigas Nakai

    NASA Astrophysics Data System (ADS)

    Seo, Hye-Young; Kim, Jun-Hyoung; Song, Hyun-Pa; Kim, Dong-Ho; Byun, Myung-Woo; Kwon, Joog-Ho; Kim, Kyong-Su

    2007-11-01

    The study was carried out to determine the effects of gamma irradiation on the volatile flavor components including essential oils, of Angelica gigas Nakai. The volatile organic compounds from non- and irradiated A. gigas Nakai at doses of 1, 3, 5, 10 and 20 kGy were extracted by a simultaneous steam distillation and extraction (SDE) method and identified by GC/MS analysis. A total of 116 compounds were identified and quantified from non- and irradiated A. gigas Nakai. The major volatile compounds were identified 2,4,6-trimethyl heptane, α-pinene, camphene, α-limonene, β-eudesmol, α-murrolene and sphatulenol. Among these compounds, the amount of essential oils in non-irradiated sample were 77.13%, and the irradiated samples at doses of 1, 3, 5, 10 and 20 kGy were 84.98%, 83.70%, 83.94%, 82.84% and 82.58%, respectively. Oxygenated terpenes such as β-eudesmol, α-eudesmol, and verbenone were increased after irradiation but did not correlate with the irradiation dose. The yields of active substances such as essential oil were increased after irradiation; however, the yields of essential oils and the irradiation dose were not correlated. Thus, the profile of composition volatiles of A. gigas Nakai did not change with irradiation.

  8. Gamma ray irradiated silicon nanowires: An effective model to investigate defects at the interface of Si/SiOx

    SciTech Connect

    Yin, Kui; Zhao, Yi; Liu, Liangbin; Lee, Shuit-Tong; Shao, Mingwang E-mail: xuegi@nju.edu.cn; Wang, Xiaoliang E-mail: xuegi@nju.edu.cn Xue, Gi E-mail: xuegi@nju.edu.cn

    2014-01-20

    The effect of gamma ray irradiation on silicon nanowires was investigated. Here, an additional defect emerged in the gamma-ray-irradiated silicon nanowires and was confirmed with electron spin resonance spectra. {sup 29}Si nuclear magnetic resonance spectroscopy showed that irradiation doses had influence on the Q{sup 4} unit structure. This phenomenon indicated that the unique core/shell structure of silicon nanowires might contribute to induce metastable defects under gamma ray irradiation, which served as a satisfactory model to investigate defects at the interface of Si/SiOx.

  9. Ultrastructure of Campylobacter jejuni in gamma-irradiated mouse jejunum

    SciTech Connect

    Sosula, L.; Nicholls, E.M.; Skeen, M.

    1988-04-01

    This paper describes the ultrastructure of intracellular elongated, transitional and coccoid forms of Campylobacter jejuni, in irradiated mouse jejunum infected both in vitro and in vivo and in cultured human skin fibroblasts. Jejunum of irradiated mouse incubated for 1 hour under conditions favorable to the organisms showed minimal tissue degeneration. The intracellular organisms in this material were free cytoplasmic forms showing inner membrane degeneration, loss of cytoplasmic granules, and absence of flagella. The diameter of the coccoids was up to four times that of the elongated forms, as in plate cultures. Intracellular organisms were not found in challenged unirradiated controls, indicating that irradiation of mouse cells may be required for intracellular infection with human strains of C jejuni. In contrast, challenged human fibroblasts contained typical elongated organisms in cytoplasmic vacuoles. These findings are discussed with reference to Campylobacter strain, host resistance, and natural animal and human Campylobacter infections.

  10. Sulfur-containing components of gamma-irradiated garlic bulbs

    NASA Astrophysics Data System (ADS)

    Kwon, Joong-Ho; Choi, Jong-Uck; Yoon, Hyung-Sik

    Sulfur-containing components associated with garlic flavors were investigated to determine the effect of γ-irradiation at 0.1 kGy on the quality of garlic bulbs ( Allium sativum L.) during storage at 3±1°C and 80±5% RH for 10 months. Irradiation treatment had no influence on the amount of total sulfur and thiosulfinate of stored garlic for 10 months, while the storage period brought about a significant reduction ( P<0.05) in the content of both components after the 6-8th month of storage compared with that at the beginning of storage period. The identity of irradiated alliin ( S-allyl- L-cysteine sulfoxide) at sprout-inhibition dose was confirmed according to thin-layer chromatography, i.r. and NMR spectroscopy data.

  11. Changes of the immune reactivities of antibodies produced against gamma-irradiated antigen

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Lee, Ju-Woon; Seo, Ji-Hyun; Kim, Jae-Hun; Jo, Cheorun; Kim, Dong-Ho; Chung, Hyung-Wook

    2004-09-01

    To observe the changes of immunogenicity and antigenicity of gamma-irradiated ovalbumin (OVA), an antigen (Ag) solution (2.0 mg/ml) was prepared and irradiated with the absorbed doses of 3 and 10 kGy. Immunoglobulin G (IgG) was produced for each Ag. 0, 3 and 10 kGy-IgG were individually reacted against 3 Ags in an ELISA cross reactivity test. Cross reactivity of each IgG was significantly different for each Ag. Especially the 10 kGy-irradiated OVA lost most antigenicity compared to the 0 kGy-IgG.

  12. Crosslinking of metallocenic α-olefin propylene copolymers by vacuum gamma irradiation

    NASA Astrophysics Data System (ADS)

    Satti, A. J.; Andreucetti, N. A.; Quijada, R.; Vallés, E. M.

    2012-12-01

    Metallocenic polypropylene and copolymers with 3.7, and 9.2 mol% of hexene and 3.0 mol% of octadecene comonomer content were synthesized without the presence of additives and irradiated with 60Co gamma radiation under vacuum at room temperature. Size Exclusion Cromatography and gel extraction data showed that scission reactions predominate over crosslinking in the homopolymer and that there is a dose from where crosslinking started to increase considerably, in the irradiated copolymers. Rheology also showed evidence of chain-enlargements on the copolymers by means of an increase in the viscoelastic properties of the irradiated material.

  13. Effect of gamma irradiation on mechanical properties of human cortical bone: influence of different processing methods.

    PubMed

    Kaminski, Artur; Jastrzebska, Anna; Grazka, Ewelina; Marowska, Joanna; Gut, Grzegorz; Wojciechowski, Artur; Uhrynowska-Tyszkiewicz, Izabela

    2012-08-01

    The secondary sterilisation by irradiation reduces the risk of infectious disease transmission with tissue allografts. Achieving sterility of bone tissue grafts compromises its biomechanical properties. There are several factors, including dose and temperature of irradiation, as well as processing conditions, that may influence mechanical properties of a bone graft. The purpose of this study was to evaluate the effect of gamma irradiation with doses of 25 or 35 kGy, performed on dry ice or at ambient temperature, on mechanical properties of non-defatted or defatted compact bone grafts. Left and right femurs from six male cadaveric donors aged from 46 to 54 years, were transversely cut into slices of 10 mm height, parallel to the longitudinal axis of the bone. Compact bone rings were assigned to the eight experimental groups according to the different processing method (defatted or non-defatted), as well as gamma irradiation dose (25 or 35 kGy) and temperature conditions of irradiation (ambient temperature or dry ice). Axial compression testing was performed with a material testing machine. Results obtained for elastic and plastic regions of stress-strain curves examined by univariate analysis are described. Based on multivariate analysis it was found that defatting of bone rings had no significant effect on any mechanical parameter studied, whereas irradiation with both doses decreased significantly the ultimate strain and its derivative toughness. The elastic limit and resilience were significantly increased by irradiation with the dose 25 kGy, but not 35 kGy, when the time of irradiation was longer. Additionally, irradiation at ambient temperature decreased maximum load, elastic limit, resilience, and ultimate stress. As strain in the elastic region was not affected, decreased elastic limit resulted in lower resilience. The opposite phenomenon was observed in the plastic region, where in spite of the lower ultimate stress, the toughness was increased due to the

  14. Parotid gland pathophysiology after mixed gamma and neutron irradiation of cancer patients

    SciTech Connect

    Anderson, M.W.; Izutsu, K.T.; Rice, J.C.

    1981-11-01

    Electrolyte and protein concentrations were measured in parotid saliva samples obtained from patients receiving localized, fractionated, neutron and gamma irradiation for the treatment of cancer. Salivary sodium chloride concentration increased transiently but then usually decreased to preirradiation values after 2 weeks of therapy. There were concurrent decreases in salivary flow rate, pH, and bicarbonate concentration. The decreases in sodium chloride concentration and flow rate are inconsistent with a previously suggested, irradiation-induced ductal sodium resorption defect. The findings contribute toward understanding how salivary gland physiology is altered in irradiation injury.

  15. The effect of gamma irradiation on curcumin component of Curcuma domestica

    NASA Astrophysics Data System (ADS)

    Chosdu, R.; Erizal; Iriawan, T.; Hilmy, N.

    1995-02-01

    The effect of gamma irradiation on curcumin component of Curcuma domestica rhizome were investigated. Pure curcumin, sliced and powdered rhizome with 10% of moisture content were irradiated at 0, 10, 30 and 50 kGy (dose rate of 6 kGy/h). Curcumin content was analysed using HPLC method and ESR spectra. Results show that free radicals are already present in unirradiated rhizome. Gamma irradiation at the doses of 10, 30 and 50 kGy induced the free radicals formation of pure curcumin and Curcuma domestica rhizome. The ESR spectra of irradiated rhizome gave a very similar spectra to the signal of irradiated pure curcumin. The percentage of free radicals intensity from pure curcumin was very stable at room temperature up to 670 hours of storage. However, the percentage intensity of free radicals in the irradiated rhizome were decay during storage. Irradiation treatment and storage time did not give a significant change on curcumin content, water activity, pH and moisture content of rhizome investigated.

  16. The effect of cryogenic freezing and gamma irradiation on the survival of Salmonella on frozen shrimp

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unfortunately, contraction of foodborne illness due to consumption of contaminated seafood, including shrimp, is an occasional occurrence. Cryogenic freezing and gamma irradiation are safe and effective technologies that can be used to control and inactivate pathogenic bacteria in foods. In this stu...

  17. Gamma-irradiation effect on material properties behaviour of semiconductor package

    NASA Astrophysics Data System (ADS)

    Yusoff, Wan Yusmawati Wan; Jalar, Azman; Othman, Norinsan Kamil; Rahman, Irman Abdul

    2013-05-01

    Current trends in digitization led to the application of an electronic package in many fields which are exposed to radioactive environment. Quad-Flat No-Lead (QFN) package technology is among the latest form of semiconductor package development in submicron size scale. A QFN package is designed by combining multimaterial and multitechnology. The ability to predict and eventually to prevent mechanical failures of microelectronics has becoming increasingly important in the development of semiconductor technology. Therefore, the relationship between the microstructure property behaviour of QFN semiconductor package and gamma irradiation has been investigated. The inhouse fabricated QFN was exposed to gamma radiation from a Cobalt-60 source with different doses varies from 0.5 Gy, and 50.0 kGy. Following, the packages were then subjected to Scanning Acoustic Microscope (CSAM) and X-ray Imaging System (3D X-ray) in order to identify internal discontinuity due to irradiation. In this investigation, the three point bending technique was used to obtain the flexural strength of the package. Irradiation packages have shown a decrease in their flexural strength with the increasing of gamma dose. In-depth analysis exhibited that the increment of exposure dose also influenced the occurrence of delamination between silicon die and copper leadframe. The cracks were also observed on the surface of the silicon die. The gamma irradiation is believed to play an important role towards the microstructure property behaviour of SDQFN package.

  18. Formation of biologically relevant carboxylic acids during the gamma irradiation of acetic acid

    NASA Technical Reports Server (NTRS)

    Negron-Mendoza, A.; Ponnamperuma, C.

    1976-01-01

    Irradiation of aqueous solutions of acetic acid with gamma rays produced several carboxylic acids in small yield. Their identification was based on the technique of gas chromatography combined with mass spectrometry. Some of these acids are Krebs Cycle intermediates. Their simultaneous formation in experiments simulating the primitive conditions on the earth suggests that metabolic pathways may have had their origin in prebiotic chemical processes.

  19. Degradation of 3-chloro-4-hydroxybenzoic acid in biological treated effluent by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Chu, Libing; Wang, Jianlong

    2016-02-01

    Gamma irradiation-induced degradation of a chlorinated aromatic compound, 3-chloro-4-hydroxybenzoic acid (CHBA) in biological treated effluent was studied and the results were compared with those obtained in deionized water. Gamma irradiation led to a complete decomposition of CHBA and a partial mineralization in the treated effluent. The removal of CHBA followed the pseudo first-order reaction kinetic model and the rate constant in the treated effluent was 1.7-3.5 times lower than that in deionized water. The CHBA degradation rate was higher at acidic condition than at neutral and alkaline conditions. The radiolytic yield, G-value for CHBA degradation was lower in the treated effluent, which decreased with increase in absorbed doses and increased with increase in initial concentrations of CHBA. The degradation mechanism of CHBA using gamma irradiation was proposed through the oxidation by -OH and reduction by eaq- and H- radicals. As exposed to gamma irradiation, dechlorination takes place rapidly and combines with the oxidation and cleavage of the aromatic ring, producing chloride ions, small carboxylic acids, acetaldehyde and other intermediates into the solution.

  20. The effect of gamma-irradiation on drug release from bioerodible microparticles: a quantitative treatment.

    PubMed

    Faisant, N; Siepmann, J; Oury, P; Laffineur, V; Bruna, E; Haffner, J; Benoit, J

    2002-08-21

    The two major objectives of this study were: (i) to monitor the effect of different gamma-irradiation doses (4-33 kGy) on the release kinetics from 5-fluorouracil (5-FU)-loaded poly(D,L-lactide-co-glycolide) (PLGA)-based microparticles, and (ii) to analyze the obtained experimental data with a new mathematical model giving insight into the occurring mass transport phenomena. Drug release was found to depend significantly on the applied gamma-irradiation dose. Interestingly, the obtained release profiles were all biphasic: a rapid initial drug release phase ("burst") was followed by a slower, approximately constant drug release phase. Surprisingly, only the initial rapid drug release was accelerated by gamma-irradiation; the subsequent zero-order phase was almost unaffected. Importantly, the new mathematical model which is based on Fick's second law of diffusion and which considers polymer degradation was applicable to all the investigated systems. In addition, the gamma-irradiation dose could be quantitatively related to the resulting drug release rate. In conclusion, diffusion seems to be the dominating release rate controlling mechanism in all cases, with a significant contribution of the polymer degradation process. PMID:12176264

  1. Electrical Properties of Gamma Irradiated PVdF Based Polymer Electrolytes

    SciTech Connect

    Ayoub, N.; Amin, Y. M.; Arof, A. K.

    2010-07-07

    The effect of different doses of {gamma}-irradiation on the conductivity of PVdF-LiPF{sub 6} solid polymer electrolyte (SPE) was investigated at room temperature. The dielectric constant and loss are seen to increase with increasing radiation doses.

  2. Immunization of baboons with Schistosoma mansoni cercariae attenuated by gamma irradiation

    SciTech Connect

    Stek, M. Jr.; Minard, P.; Dean, D.A.; Hall, J.E.

    1981-06-26

    Studies on the efficacy of a vaccine against schistosomiasis in young baboons (Papio anubis) disclosed that immunization with Schistosoma mansoni cercariae attenuated by gamma irradiation induced significant protection against subsequent infection with normal, viable S. mansoni cercariae. Such immunization resulted in reduced worm burdens (70%) and egg excretion rates (82%). These results support immunization as a potential method for schistosomiasis control.

  3. Immunization of Baboons with Schistosoma mansoni Cercariae attenuated by gamma irradiation

    SciTech Connect

    Stek, M.; Minard, P.; Dean, D.A.; Hall, J.E.

    1981-06-01

    Studies on the efficacy of a vaccine against schistosomiasis in young baboons (Papio anubis) disclosed that immunization with Schistosoma mansoni cercariae attenuated by gamma irradiation induced significant protection against subsequent infection with normal, viable S. mansoni cercariae. Such immunization resulted in reduced worm burdens (70 percent) and egg excretion rates (82 percent). These results support immunization as a potential method for schistosomiasis control.

  4. Enhanced mass transfer during solid liquid extraction of gamma-irradiated red beetroot

    NASA Astrophysics Data System (ADS)

    Nayak, Chetan A.; Chethana, S.; Rastogi, N. K.; Raghavarao, K. S. M. S.

    2006-01-01

    The exposure to gamma-irradiation pretreatment increases cell wall permeabilization, resulting in loss of turgor pressure, which led to the increase of extractability of betanin from red beetroot. The degree of extraction of betanin was investigated using gamma irradiation as a pretreatment prior to the solid-liquid extraction process and compared with control beetroot samples. The beetroot subjected to different doses of gamma irradiation (2.5, 5.0, 7.5, 10.0 kGy) and control was dipped in an acetic acid medium (1% v/v) to extract the betanin. The diffusion coefficients for betanin as well as ionic component were estimated considering Fickian diffusion. The results indicated an increase in the diffusion coefficient of betanin (0.302×10 -9-0.463×10 -9 m 2/s) and ionic component (0.248×10 -9-0.453×10 -9 m 2/s) as the dose rate increased (from 2.5 to 10.0 kGy). The degradation constant was found to increase (0.050-0.079 min -1) with an increase gamma-irradiation doses (2.5-10.0 kGy), indicating lower stability of the betanin as compared to control sample at 65 °C.

  5. Spin-trap-radical chromatography of spin adducts produced from L-valine by. gamma. -irradiation

    SciTech Connect

    Makiino, K.; Suzuki, N.; Moriya, F.; Rokushika, S.; Hatano, H.

    1980-01-01

    Diastereomeric spin adducts produced by reaction of 2-methyl-2-nitrosopropane with the short-lived radicals from L-valine by ..gamma..-irradiation could be separated and identified by means of high performance liquid chromatography and ESR spectroscopy. 6 figures.

  6. Phototherapeutic Effect of Low-Level Laser on Thyroid Gland of Gamma-Irradiated Rats.

    PubMed

    Morcos, Nadia; Omran, Manar; Ghanem, Hala; Elahdal, Mahmoud; Kamel, Nashwa; Attia, Elbatoul

    2015-01-01

    One inescapable feature of life on the earth is exposure to ionizing radiation. The thyroid gland is one of the most sensitive organs to gamma-radiation and endocrine disrupters. Low-level laser therapy (LLLT) has been used to stimulate tissue repair, and reduce inflammation. The aim of this study was to gauge the value of using Helium-Neon laser to repair the damaged tissues of thyroid gland after gamma-irradiation. Albino rats were used in this study (144 rats), divided into control, gamma, laser, and gamma plus laser-irradiated groups, each group was divided into six subgroups according to time of treatment (total six sessions). Rats were irradiated once with gamma radiation (6 Gy), and an external dose of laser (Wavelength 632.8 nm, 12 mW, CW, Illuminated area 5.73 cm(2), 2.1 mW cm(-2) 120 s, 1.4 J, 0.252 J cm(-2)) twice weekly localized on thyroid region of the neck, for a total of six sessions. Animals were sacrificed after each session. Analysis included thyroid function, oxidative stress markers, liver function and blood picture. Results revealed improvement in thyroid function, liver function and antioxidant levels, and the blood cells count after LLLT.

  7. Phototherapeutic Effect of Low-Level Laser on Thyroid Gland of Gamma-Irradiated Rats.

    PubMed

    Morcos, Nadia; Omran, Manar; Ghanem, Hala; Elahdal, Mahmoud; Kamel, Nashwa; Attia, Elbatoul

    2015-01-01

    One inescapable feature of life on the earth is exposure to ionizing radiation. The thyroid gland is one of the most sensitive organs to gamma-radiation and endocrine disrupters. Low-level laser therapy (LLLT) has been used to stimulate tissue repair, and reduce inflammation. The aim of this study was to gauge the value of using Helium-Neon laser to repair the damaged tissues of thyroid gland after gamma-irradiation. Albino rats were used in this study (144 rats), divided into control, gamma, laser, and gamma plus laser-irradiated groups, each group was divided into six subgroups according to time of treatment (total six sessions). Rats were irradiated once with gamma radiation (6 Gy), and an external dose of laser (Wavelength 632.8 nm, 12 mW, CW, Illuminated area 5.73 cm(2), 2.1 mW cm(-2) 120 s, 1.4 J, 0.252 J cm(-2)) twice weekly localized on thyroid region of the neck, for a total of six sessions. Animals were sacrificed after each session. Analysis included thyroid function, oxidative stress markers, liver function and blood picture. Results revealed improvement in thyroid function, liver function and antioxidant levels, and the blood cells count after LLLT. PMID:25975382

  8. Evaluation of the efficiency and throughput of a gamma irradiator treating municipal sewage sludge.

    PubMed

    Benny, P G; Shah, M R; Sabharwal, S

    2011-03-01

    Sludge Hygienisation Research Irradiator (SHRI) Facility at Vadodara (India) has been disinfecting liquid sewage sludge with (60)Co gamma rays since 1992. At some point, the radiation process was modified from its originally designed closed-loop system to an open-loop system. Dosimetry experiments were performed to estimate absorbed doses to the sludge for different periods of irradiation of a 15m(3) batch in an open-loop irradiation process. The paper reports the dosimetry results and evaluated operational parameters of the irradiator, namely, effective dose rate in the open-loop system, irradiation efficiency, and throughput. Also, the open-loop system and the closed-loop system are compared in terms of the effective dose rate.

  9. Radiosterilisation of indomethacin PLGA/PEG-derivative microspheres: protective effects of low temperature during gamma-irradiation.

    PubMed

    Fernández-Carballido, Ana; Puebla, Patricia; Herrero-Vanrell, Rocío; Pastoriza, Pilar

    2006-04-26

    Currently, gamma-irradiation seems to be a good method for sterilising drug delivery systems made from biodegradable polymers. The gamma-irradiation of microspheres can cause several physicochemical changes in the polymeric matrix. These modifications are affected by the temperature, irradiation dose and nature of the encapsulated drug and additives. This study has aimed to evaluate the influence of temperature during the sterilisation process by gamma irradiation in indomethacin PLGA microspheres including a PEG-derivative. Microspheres were prepared by the solvent evaporation method from o/w emulsion and were then exposed to gamma-irradiation. A dose of 25 kGy was used to ensure effective sterilisation. Some microspheres were sterilised with dry ice protection that guaranteed a low temperature during the process whilst others were sterilised without such dry ice protection. The effects of gamma-irradiation on the characteristics of non-loaded PLGA/PEG-derivative and indomethacin loaded PLGA/PEG-derivative microspheres with and without protection were studied. Non-protected microspheres showed changes in their morphological surface, polymer glass transition temperature, molecular weight and release rate of indomethacin after sterilisation. However, microspheres sterilised with protection did not show significant differences after gamma-irradiation exposure. The sterilisation method was satisfactory when the indomethacin loaded microspheres including a PEG-derivative were exposed to gamma-irradiation at low temperature.

  10. Physicochemical, functional and pasting properties of flour produced from gamma irradiated tiger nut (Cyperus esculentus L.)

    NASA Astrophysics Data System (ADS)

    Ocloo, Fidelis C. K.; Okyere, Abenaa A.; Asare, Isaac K.

    2014-10-01

    Tiger nut (Cyperus esculentus L.) has been recognised as one of the best nutritional crops that can be used to augment the Ghanaian diet. The application of gamma irradiation as means of preserving tiger nut could modify the characteristics of resultant flour. The purpose of this study was to determine the physicochemical, functional and pasting characteristics of flour from gamma irradiated tiger nut. The yellow and black types of tiger nut were sorted, washed and dried in an air-oven at 60 oC for 24 h. The dried tiger nut samples were irradiated at 0.0, 2.5, 5.0 and 10.0 kGy and then flours produced from them. Moisture, ash, pH, titratable acidity, water and oil absorption capacities, swelling power, solubility, bulk density and pasting properties of the flours were determined using appropriate analytical methods. Results showed that irradiation did not significantly (P>0.05) affect the moisture and ash contents of the resultant flours. Gamma irradiation significantly (P≤0.05) increased titratable acidity with concomitant decrease in pH of the flours. No significant differences were observed for water and oil absorption capacities, swelling power as well as bulk density. Solubility significantly (P≤0.05) increased generally with irradiation dose. Peak viscosity, viscosities at 92 °C and 55 °C, breakdown and setback viscosities decreased significantly with irradiation dose. Flour produced from irradiated tiger nut has a potential in complementary food formulations due to its low viscosity and increased solubility values.

  11. Environmental application of gamma technology: Update on the Canadian sludge irradiator

    NASA Astrophysics Data System (ADS)

    Swinwood, Jean F.; Fraser, Frank M.

    1993-10-01

    Waste treatment and disposal technologies have recently been subjected to increasing public and regulatory scrutiny. Concern for the environment and a heightened awareness of potential health hazards that could result from insufficient or inappropriate waste handling methods have combined to push waste generators in their search for new treatment alternatives. Gamma technology can offer a new option for the treatment of potentially infectious wastes, including municipal sewage sludge. Sewage sludge contains beneficial plant nutrients and a high organic component that make it ideal as a soil conditioning agent or fertilizer bulking material. It also carries potentially infectious microorganisms which limit opportunities for beneficial recycling of sludges. Gamma irradiation-disinfection of these sludges offers a reliable, fast and efficient method for safe sludge recycling. Nordion International's Market Development Division was created in 1987 as part of a broad corporate reorganization. It was given an exclusive mandate to develop new applications of gamma irradiation technology and markets for these new applications. Nordion has since explored and developed opportunities in food irradiation, pharmaceutical/cosmetic products irradiation, biomedical waste sterilization, airline waste disinfection, and sludge disinfection for recycling. This paper focuses on the last of these -a proposed sludge recycling facility that incorporates a cobalt 60 sludge irradiator.

  12. Effects of gamma-ray irradiation on leaching of simulated 133Cs+ radionuclides from geopolymer wasteforms

    NASA Astrophysics Data System (ADS)

    Deng, Ning; An, Hao; Cui, Hao; Pan, Yang; Wang, Bing; Mao, Linqiang; Zhai, Jianping

    2015-04-01

    Leaching of simulated 133Cs+ radionuclides from geopolymer wasteforms was examined with regard to effects from gamma-ray irradiation. Specifically, the compressive strengths, microstructures, pore structures, and leaching resistance of geopolymer wasteforms before and after irradiation were characterized. The leaching experiments were performed by immersion of wasteforms in deionized water, ground water, and seawater. It was found that gamma rays did not produce significant morphological changes, except for changes in the pore size distribution. The cumulative leaching fraction of all the leachants from the irradiated samples increased relative to the non-radiated samples, particularly during long leaching periods (11-42 days). These results, and those from a mercury intrusion porosimeter analysis, can be attributed to irradiation-induced changes in pore structure. All the leaching indexes were greater than the minimum acceptable value of 6.0 set by the American Nuclear Society Standards committee, which indicated that the fly-ash geopolymers are suitable for radionuclide immobilization. However, the effects of gamma-ray irradiation on the immobilization of radionuclides cannot be ignored.

  13. Physicochemical properties of brown rice as influenced by gamma irradiation, variety and storage

    SciTech Connect

    Sabularse, V.C.

    1988-01-01

    Effects of gamma irradiation, variety and storage on physicochemical properties of brown rice from three Louisiana rice varieties: Mars, a medium grain variety, Lemont and Tebonnet, long grain varieties, were determined. Cooking time was significantly reduced in Mars and Lemont at doses of 200 and 300 Krads. Irradiation increased cooking rate, water uptake at 80{degree}C, water uptake ratios, total solids content in residual cooking liquid and starch damage from 100 to 300 Krad samples. Water uptake at 96{degree}C generally decreased with increasing dose levels. Evidence indicated alterations in the rice grain structures and composition. The component drastically affected by gamma irradiation was starch as shown by reduced cooking time, increased water uptake, increased amounts of starch and protein in residual cooking liquid, reduced volume expansion, increased damage starch and changes in amylographic pasting characteristics. Scanning electron microscopy showed more simple starch granules in irradiated samples than in nonirradiated samples. Structural changes in the bran layer due to gamma irradiation were not evident from electron micrographs.

  14. Induction of L-arabinose isomerase in gamma-irradiated Escherichia coli

    SciTech Connect

    Chatterjee, A.; Bhattacharya, A.K.

    1986-11-01

    Gamma irradiation of Escherichia coli B/r caused a dose-dependent inhibition of the capacity of the cells to synthesize L-arabinose isomerase in response to the inducer. At higher doses (18 krad and above), postirradiation incubation led to further inhibition of the capacity to synthesize L-arabinose isomerase, whereas cells receiving lower doses recovered from the damage to the enzyme synthesizing system following incubation. Cyclic AMP partially reversed the inhibitory effect on L-arabinose isomerase induction produced immediately after irradiation by all gamma-ray doses (up to 30 krad), but the enhanced inhibitory effect caused by induction in cells irradiated at higher doses could not be reversed by the nucleotide. It is suggested that although catabolite repression is partly responsible for causing the inhibition of the enzyme synthesizing capacity of the cells observed immediately after gamma irradiation, the enhanced inhibition caused by incubating cells irradiated at higher doses is not due to interference with the control mechanism regulated by catabolite repression.

  15. Crease recovery properties of cotton fabrics modified by urea resins under the effect of gamma irradiation

    NASA Astrophysics Data System (ADS)

    Hassan, Mahmoud S.

    2009-05-01

    Cotton fabrics initially dyed with reactive dyes were treated with dimethylol dihydroxy ethylene urea (DMDHEU) resin in order to improve the crease recovery properties. As a comparison, the treatment with DMDHEU was carried out by the conventional thermal curing and gamma irradiation. The effect of treatments on the colour properties, crease recovery, mechanical and thermal properties was studied. It was found that the finishing of cotton fabrics with gamma irradiation affords better crease recovery values at low doses without affecting the colour intensity and the physical properties than the finishing by thermal curing. However, the finishing with higher doses of gamma radiation affects the mechanical properties of cotton fabrics. On the other hand, it was found that the thermal properties were improved with increasing dose.

  16. Gamma Irradiation of Active Self-healing PLGA Microspheres for Efficient Aqueous Encapsulation of Vaccine Antigens

    PubMed Central

    Desai, Kashappa-Goud H.; Kadous, Samer; Schwendeman, Steven P.

    2013-01-01

    Purpose To investigate the effect of γ-irradiation of poly(lactic-co-glycolic acid) (PLGA)/Al(OH)3/0 or 5 wt% diethyl phthalate (DEP) microspheres for active self-healing encapsulation of vaccine antigens. Methods Microspheres were irradiated with 60Co at 2.5 and 1.8 MRad and 0.37 and 0.20 MRad/h. Encapsulation of tetanus toxoid (TT) was achieved by mixing Al(OH)3-PLGA microspheres with TT solution at 10-38°C. Electron paramagnetic resonance (EPR) spectroscopy was used to examine free radical formation. Glass transition temperature (Tg) and molecular weight of PLGA was measured by differential scanning calorimetry and gel permeation chromatography, respectively. Loading and release of TT were examined by modified Bradford, amino acid analysis, and ELISA assays. Results EPR spectroscopy results indicated absence of free radicals in PLGA microspheres after γ-irradiation. Antigen-sorbing capacity, encapsulation efficiency, and Tg of the polymer were also not adversely affected. When DEP-loaded microspheres were irradiated at 0.2 MRad/h, some PLGA pores healed during irradiation and PLGA healing during encapsulation was suppressed. The molecular weight of PLGA was slightly reduced when DEP-loaded microspheres were irradiated at the same dose rate. These trends were not observed at 0.37 MRad/h. Gamma irradiation slightly increased TT initial burst release. Apart from the slightly higher polymer molecular weight decline caused by higher irradiation dose in case of DEP-loaded microspheres, the small increase in total irradiation dose from 1.8 to 2.5 MRad had insignificant effect on the polymer and microspheres properties analyzed. Conclusion Gamma irradiation is a plausible approach to provide a terminally sterilized, self-healing encapsulation PLGA excipient for vaccine delivery. PMID:23515830

  17. Induced parthenogenesis by gamma-irradiated pollen in loquat for haploid production

    PubMed Central

    Blasco, Manuel; Badenes, María Luisa; del Mar Naval, María

    2016-01-01

    Successful haploid induction in loquat (Eriobotrya japonica (Thunb.) Lindl.) through in situ-induced parthenogenesis with gamma-ray irradiated pollen has been achieved. Female flowers of cultivar ‘Algerie’ were pollinated using pollen of cultivars ‘Changhong-3’, ‘Cox’ and ‘Saval Brasil’ irradiated with two doses of gamma rays, 150 and 300 Gy. The fruits were harvested 90, 105 and 120 days after pollination (dap). Four haploid plants were obtained from ‘Algerie’ pollinated with 300-Gy-treated pollen of ‘Saval Brasil’ from fruits harvested 105 dap. Haploidy was confirmed by flow cytometry and chromosome count. The haploids showed a very weak development compared to the diploid plants. This result suggests that irradiated pollen can be used to obtain parthenogenetic haploids. PMID:27795686

  18. Quality characteristics of oil extracted from gamma irradiated peanut (Arachis hypogea L.)

    NASA Astrophysics Data System (ADS)

    Al-Bachir, Mahfouz

    2015-01-01

    The effect of gamma radiation and storage on the characteristics of oil extracted from peanut seeds has been investigated in this study. Peanut seeds were undergone gamma irradiation process with the doses of 1, 2 and 3 kGy. The changes in chemical and physical attributes were observed immediately after irradiation and after 12 months of storage. The data obtained from the experiments showed that irradiation process had no effect on the chemical and physical qualities such as, fatty acid composition, peroxide value, iodine value specification number, TBA value and color of oil extracted from peanut seeds. On the contrary, the peroxide, acidity and TBA values of the peanut oil were decreased due to storage time.

  19. Suitability of gamma irradiation for preserving fresh-cut watercress quality during cold storage.

    PubMed

    Pinela, José; Barreira, João C M; Barros, Lillian; Verde, Sandra Cabo; Antonio, Amilcar L; Carvalho, Ana Maria; Oliveira, M Beatriz P P; Ferreira, Isabel C F R

    2016-09-01

    The suitability of gamma irradiation (1, 2 and 5kGy) for preserving quality parameters of fresh-cut watercress (Nasturtium officinale R. Br.) during storage at 4±1°C for 7d was investigated. The storage time decreased the protein content and the main carbohydrates, and increased the levels of malic and fumaric acids, sucrose and mono- and polyunsaturated fatty acids (MUFA and PUFA). The different irradiation doses did not caused any significant colour change. In general, the 2kGy dose favoured PUFA and was the most suitable to preserve the overall postharvest quality of fresh-cut watercress during cold storage. In turn, the 5kGy dose better preserved the antioxidant activity and total flavonoids and favoured MUFA, tocopherols and total phenolics, thus originating a final product with enhanced functional properties. Therefore, the suitability of gamma irradiation for preserving fresh-cut watercress quality during cold storage was demonstrated.

  20. Synthesis and characterization of zinc chloride containing poly(acrylic acid) hydrogel by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Park, Jong-Seok; Kuang, Jia; Gwon, Hui-Jeong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Seob Khil, Myung; Nho, Young-Chang

    2013-07-01

    In this study, the characterization of zinc chloride incorporated into a poly(acrylic acid) (PAAc) hydrogel prepared by gamma-ray irradiation was investigated. Zinc chloride powder with different concentrations was dissolved in the PAAc solution, and it was crosslinked with gamma-ray irradiation. The effects of various parameters such as zinc ion concentration and irradiation doses on characteristics of the hydrogel formed were investigated in detail for obtaining an antibacterial wound dressing. In addition, the gel content, pH-sensitive (pH 4 or 7) swelling ratio, and UV-vis absorption spectra of the zinc particles in the hydrogels were characterized. Moreover, antibacterial properties of these new materials against Staphylococcus aureus and Escherichia coli strains were observed on solid growth media. The antibacterial tests indicated that the zinc chloride containing PAAc hydrogels have good antibacterial activity.

  1. Gamma irradiation of cultural artifacts for disinfection using Monte Carlo simulations.

    PubMed

    Choi, Jong-il; Yoon, Minchul; Kim, Dongho

    2012-11-01

    In this study, it has been investigated the disinfection of Korean cultural artifacts by gamma irradiation, simulating the absorbed dose distribution on the object with the Monte Carlo methodology. Fungal contamination was identified on two traditional Korean agricultural tools, Hongdukkae and Holtae, which had been stored in a museum. Nine primary species were identified from these items: Bjerkandera adusta, Dothideomycetes sp., Penicillium sp., Cladosporium tenuissimum, Aspergillus versicolor, Penicillium sp., Entrophospora sp., Aspergillus sydowii, and Corynascus sepedonium. However, these fungi were completely inactivated by gamma irradiation at an absorbed dose of 20kGy on the front side. Monte Carlo N Particle Transport Code was used to simulate the doses applied to these cultural artifacts, and the measured dose distributions were well predicted by the simulations. These results show that irradiation is effective for the disinfection of cultural artifacts and that dose distribution can be predicted with Monte Carlo simulations, allowing the optimization of the radiation treatment.

  2. Major alteration of the pathological phenotype in gamma irradiated mdx soleus muscles

    SciTech Connect

    Weller, B.; Karpati, G.; Lehnert, S.; Carpenter, S. )

    1991-07-01

    Two thousand rads of gamma irradiation delivered to the lower legs of ten day old normal and x-chromosome linked muscular dystrophy (mdx) mice caused significant inhibition of tibial bone and soleus muscle fiber growth. In the irradiated mdx solei, there was a major loss of muscle fibers, lack of central nucleation, and some endomysial fibrosis. These features were caused by a failure of regeneration of muscle fibers due to impaired proliferative capacity of satellite cells. Gamma irradiation transforms the late pathological phenotype of mdx muscles, so that in one major aspect (muscle fiber loss) they resemble muscles in Duchenne muscular dystrophy. However, extensive endomysial fibrosis which is another characteristic feature of Duchenne muscular dystrophy did not develop. This experimental model could be useful for the functional investigation of possible beneficial effects of therapeutic interventions in mdx dystrophy.

  3. Preservative solution for gamma irradiated chrysanthemum cut flowers

    NASA Astrophysics Data System (ADS)

    Kikuchi, Olivia Kimiko; Del Mastro, Nelida Lucia; Wiendl, Frederico Maximiliano

    1995-09-01

    Yellow mini-chrysanthemums were irradiated in a Cobalt-60 Gammacell at the dose of 900 Gy (467 Gy/h) one day after harvest. Samples of 50 flowers, parcially opened buds were used to estimate the flower viability. Aluminum sulfate and 8-hydroxyquinoline sulfate were used as two preservative solutions aiming to protect the cut flowers. Our results indicated that the stem immersion in the preservative solutions before and after the irradiation treatment was an efficient procedure, stimulating the flowers development and maintaining the vase-life almost as long as the controls. The present work concludes that it would be possible to use preservative solutions to minimize the damaging effects of the ionizing radiation on chysanthemum cut flowers, maintaining at the same time the disinfestation action of radiation processing.

  4. Thermoluminescence of simulated interstellar matter after gamma-ray irradiation. Forsterite, enstatite and carbonates

    NASA Astrophysics Data System (ADS)

    Koike, K.; Nakagawa, M.; Koike, C.; Okada, M.; Chihara, H.

    2002-08-01

    Interstellar matter is known to be strongly irradiated by cosmic radiation and several types of cosmic ray particles. Simulated interstellar matter, such as synthesized forsterite (Mg2SiO4), enstatite (MgSiO3) and magnesite (MgCO3), has been irradiated with 60Co gamma-rays in liquid nitrogen, and also irradiated with fast neutrons at 10 K and 70 K by making use of the low-temperature irradiation facility of the Kyoto University Reactor (KUR-LTL. Maximum fast neutron dose is 1017nf /cm2). After irradiation, samples are stored in liquid nitrogen for several months to allow the decay of induced radioactivity. We measured the luminescence spectra of the gamma ray irradiated samples during warming to 370 K using a spectrophotometer. For the forsterite and magnesite, the spectra exhibit a rather intense peak at about 645-655 nm and 660 nm respectively, whereas luminescence scarcely appeared in the natural olivine sample. The spectra of forsterite is very similar to the ERE of the Red Rectangle.

  5. Gamma irradiation effects on stability of poly(lactide-co-glycolide) microspheres containing clonazepam.

    PubMed

    Montanari, L; Cilurzo, F; Valvo, L; Faucitano, A; Buttafava, A; Groppo, A; Genta, I; Conti, B

    2001-08-10

    This work was aimed at evaluating the effects of gamma irradiation on the stability of microspheres made of a poly(lactide-co-glycolide) copolymer (PLGA) and loaded with 15% w/w of clonazepam (CLO). The influence of CLO on PLGA radiolysis mechanisms and the identification of possible irradiation markers were also investigated. Microspheres were prepared by means of a spray-drying method. gamma Irradiation was carried out either under vacuum or in air, at a dose of 25 kGy, by using a 60Co source. The stability of CLO loaded microspheres was evaluated over a 6-month period on the basis of drug content and dissolution profile. Radiolysis mechanisms were investigated by using electronic paramagnetic resonance (EPR) analysis. The microspheres irradiated under vacuum were stable over the considered period of time. After irradiation in air, CLO release rate increased by approximately 10%, and did not change further in the following period of storage. The EPR analysis showed some radicals arising from both the polymeric matrix and the active ingredient. Polymer/CLO spin transfer reactions suggest that CLO had a radio-stabilising effect on the polymeric matrix. In the loaded microspheres, the intensity in time of the CLO radical signal is sufficient for its possible use as irradiation marker. PMID:11489319

  6. Gamma-irradiation effect on a commercial composite anticorrosive pigment and acidity-to-alkalinity conversion

    NASA Astrophysics Data System (ADS)

    Song, Weiqiang; Niu, Kaihui; Wu, Longchao

    2016-05-01

    A commercial composite anticorrosive pigment based on aluminum dihydrogen tripolyphosphate was studied after exposure to gamma irradiation (Co60, 0, 20, 50, 100 and 150 kGy) using FTIR, XRD, TGA and acid-base titration technologies. Although the FTIR spectra showed that the effect of the irradiation on functional groups in the pigments was not obvious, the decrease in the crystal lattice parameters of the irradiated pigments was observed in the XRD spectra compared to the non-irradiated sample. But the extent of the lattice parameter decrease monotonically with the increase of absorbed dose from 20 to 150 kGy, which was attributed to the decomposition of water and the simultaneous occurrence of lattice damage when the pigments were exposed to gamma rays. Of particular significance was the displayed basicity of the aqueous solutions of the irradiated pigments compared to the acidity of the solution of the non-irradiated pigment, which was attributed to the decomposition of P-OH groups (combined water).

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  8. Protection of swiss albino mice against whole-body gamma irradiation by Mentha piperita (Linn.).

    PubMed

    Samarth, R M; Goyal, P K; Kumar, Ashok

    2004-07-01

    The radioprotective effects of Mentha oil (Mentha piperita Linn.) against radiation induced haematological alterations in peripheral blood and the survival of Swiss albino mice were studied. Mentha oil 40 micro L/animal/day for 3 consecutive days when fed orally prior to whole-body gamma irradiation (8 Gy) showed protection of the animals in terms of the survival percentage and haematological parameters in mice. Fifty per cent of the animals died within 20 days and 100% mortality was observed up to 30 days post-irradiation in the control irradiated group. Whereas only 17% of the mice died within 30 days in the experimental group (Mentha oil pretreated irradiated). The total RBC count decreased maximally at 24 h (3.45 +/- 0.20 x 10(12)/L, p < 0.001), similar observations were obtained for the WBC count, haemoglobin content and haematocrit percentage in the irradiated control animals. However, in irradiated animals pretreated with Mentha oil, although the initial values of haematological components were lower they later showed a remarkable recovery reaching normal at 30 days post-irradiation compared with the irradiated control animals. In general, the recovery of the blood cell number in irradiated animals depends on the survival of stem cells and their derivatives. The results from the present study suggest that the oil of Mentha piperita (Linn.) has a radioprotective role in stimulating/protecting the haematopoietic system. Hence, enhanced survival and an increase in the haematological constituents of peripheral blood of mice against lethal gamma radiation was observed.

  9. Effects of gamma irradiation on physicochemical properties, antioxidant and microbial activities of sour cherry juice

    NASA Astrophysics Data System (ADS)

    Arjeh, Edris; Barzegar, Mohsen; Ali Sahari, Mohammad

    2015-09-01

    Recently, due to the beneficial effects of bioactive compounds, demand for minimally processed fruits and fruit juices has increased rapidly in the world. In this study, sour cherry juice (SCJ) was exposed to gamma irradiation at 0.0, 0.5, 1.5, 3.0, 4.5, and 6.0 kGy and then stored at 4 °C for 60 days. Total soluble solids (TSS), total acidity (TA), color, total phenolic content (TPC), total monomeric anthocyanin content (TMC), antioxidant activity, organic acid profile, and microbial analysis were evaluated at regular intervals during the storage. Results indicated that irradiation did not have any significant effect on TSS, while level of TA increased significantly at the dose of 6 kGy (p<0.05). Furthermore, irradiation treatment and storage time led to a significant increase in L* and b* values and a decrease in a* values. Total monomeric anthocyanin content of the irradiated SCJ was lower than that of the non-irradiated one (24% at 3.0 kGy) and also changed toward a more negative direction during the storage (63% at 3.0 kGy for 60 days). There was a significant decrease in the antioxidant activity (DPPH radical scavenging and FRAP assay) in both irradiated and stored SCJs. After irradiation (0-6 kGy), the results showed that the concentration of malic and oxalic acid significantly increased; but, the concentration of ascorbic, citric, fumaric, and succinic acids significantly decreased. Gamma irradiation with doses of ≥3 kGy resulted in overall reduction in microbial loads. Based on the results obtained from the changes of physicochemical properties, antioxidant activity, and microbial analysis, irradiation of SCJ at doses of higher than 3.0 kGy is not recommended.

  10. Response of thyroid follicular cells to gamma irradiation compared to proton irradiation: II. The role of connexin 32

    NASA Technical Reports Server (NTRS)

    Green, L. M.; Tran, D. T.; Murray, D. K.; Rightnar, S. S.; Todd, S.; Nelson, G. A.

    2002-01-01

    The objective of this study was to determine whether connexin 32-type gap junctions contribute to the "contact effect" in follicular thyrocytes and whether the response is influenced by radiation quality. Our previous studies demonstrated that early-passage follicular cultures of Fischer rat thyroid cells express functional connexin 32 gap junctions, with later-passage cultures expressing a truncated nonfunctional form of the protein. This model allowed us to assess the role of connexin 32 in radiation responsiveness without relying solely on chemical manipulation of gap junctions. The survival curves generated after gamma irradiation revealed that early-passage follicular cultures had significantly lower values of alpha (0.04 Gy(-1)) than later-passage cultures (0.11 Gy(-1)) (P < 0.0001, n = 12). As an additional way to determine whether connexin 32 was contributing to the difference in survival, cultures were treated with heptanol, resulting in higher alpha values, with early-passage cultures (0.10 Gy(-1)) nearly equivalent to untreated late-passage cultures (0.11 Gy(-1)) (P > 0.1, n = 9). This strongly suggests that the presence of functional connexin 32-type gap junctions was contributing to radiation resistance in gamma-irradiated thyroid follicles. Survival curves from proton-irradiated cultures had alpha values that were not significantly different whether cells expressed functional connexin 32 (0.10 Gy(-1)), did not express connexin 32 (0.09 Gy(-1)), or were down-regulated (early-passage plus heptanol, 0.09 Gy(-1); late-passage plus heptanol, 0.12 Gy(-1)) (P > 0.1, n = 19). Thus, for proton irradiation, the presence of connexin 32-type gap junctional channels did not influence their radiosensitivity. Collectively, the data support the following conclusions. (1) The lower alpha values from the gamma-ray survival curves of the early-passage cultures suggest greater repair efficiency and/or enhanced resistance to radiation-induced damage, coincident with the

  11. The role of gamma irradiation on the extraction of phenolic compounds in onion (Allium cepa L.)

    NASA Astrophysics Data System (ADS)

    Yang, Eun In; Lee, Eun Mi; Kim, Young Soo; Chung, Byung Yeoup

    2012-08-01

    The effect of gamma irradiation on the content of total phenolic compounds, especially quercetin (Q), in onion (Allium cepa L.) skin was investigated. Onion skin extracts contained two predominant flavonoid compounds, Q and quercetin-4'-glucoside (Q4'G). After 10 kGy gamma irradiation, the yield of Q in the extracts increased significantly from 36.8 to 153.9 μg/ml of the extract, and the Q4'G content decreased slightly from 165.0 to 134.1 μg/ml. In addition, the total phenolic compound content also increased after irradiation at 10 kGy, from 228.0 μg/g of fresh weight to 346.6 μg/g; negligible changes (237.1-256.7 μg/g) occurred at doses of up to 5 kGy. As we expected, radical-scavenging activity was enhanced remarkably (by 88.8%) in the 10 kGy irradiated sample. A dose-dependent increase in the peak intensity of the electron paramagnetic resonance (EPR) spectra was observed in all irradiated samples, with a maximum increase at 10 kGy. The intensity relative to that of the control was 0.15, and it increased to 1.10 in 10 kGy irradiated samples. The optimum gamma irradiation dose, which is sufficient to break the chemical or physical bonds and release soluble phenols of low molecular weight in onion skin, is about 10 kGy.

  12. Gamma irradiation: a method to produce an abiotic control for biological activated carbon.

    PubMed

    Stoquart, C; Vázquez-Rodríguez, G A; Servais, P; Barbeau, B

    2013-01-01

    The aim of this paper was to investigate the feasibility of using gamma irradiation to inhibit the microbial activity of biological powder activated carbon (PAC) without impacting its adsorptive properties. First of all, the range of dose of gamma rays required to produce abiotic PAC was selected on the basis of heterotrophic plate counts (HPC) inactivation and methylene blue (MB) adsorption kinetics. Doses inferior to 10 kGy were not sufficient to inhibit the culture of heterotrophic bacteria. On the other hand, doses superior to 15 kGy were demonstrated to affect the adsorption rate of MB. Consequently, a dose comprised between 10 and 15 kGy was selected for further investigation. In order to validate the adequacy of the range of dose (i.e. 10-15 kGy), adsorption characteristics were tested by monitoring the removal kinetics of refractory dissolved organic carbon (RDOC). No significant differences were observed between irradiated and non-irradiated biological PAC for the adsorption of RDOC. Irradiated, non-irradiated and virgin PAC were also evaluated in terms of abundance of viable (using the LIVE/DEAD BacLight method) bacteria and in terms of heterotrophic biomass activity. The results of the BacLight method demonstrated that attachment of the biofilm on the PAC was not impacted by the irradiation and heterotrophic activity measurements demonstrated that the latter could be radically reduced in the range of dose selected. In conclusion, when using a proper dose, the gamma irradiation of colonized activated carbon drastically reduced the heterotrophic activity on activated carbon without significantly impacting its adsorptive behaviour. PMID:24617066

  13. Gamma irradiation of the fetus damages the developing hemopoietic microenvironment rather than the hemopoietic progenitor cells

    SciTech Connect

    Yang, F.T.; Lord, B.I.; Hendry, J.H.

    1995-03-01

    Hemopoiesis is the product of two components: the hemopoietic tissue and the regulatory stromal microenvironment in which it resides. Plutonium-239, incorporated during fetal development in mice, is known to cause deficient hemopoiesis. A predetermined equivalent {gamma}-ray dose has now been used in combination with cross-transplantation experiments to separate these two components and define where the damage arises. It was confirmed that 1.8 Gy {gamma} irradiation at midterm gestation caused a 40% reduction in the hemopoietic stem (spleen colony-forming) cell population of their offspring which persisted to at least 24 weeks of age. Spleen colony formation after sublethal doses of {gamma} rays reflected this reduced complement of endogenous stem cells. The regulatory hemopoietic microenvironment, measured as fibroblastoid colony-forming cells, was similarly depleted. Normal growth of the CFU-S population after transplantation into standard recipients showed that the quality of the stem cell population in the offspring of irradiated mothers was not affected. By contrast, when used as recipients of a bone marrow transplant from either normal or irradiated offspring, the offspring of irradiated mothers were unable to support normal growth: there was a twofold difference in the number of CFU-S per femur for at least 100 days after transplantation. There were 70% fewer CFU-F in the femur 1 month after bone marrow transplantation when the offspring of irradiated mothers were used as transplant recipients compared to when normal offspring were used. This not only confirmed their reduced capacity to host normal stem cells but also indicated that CFU-F in the transplant were unable to compensate for the poor microenvironment in the irradiated offspring hosts. It is concluded that irradiation at midterm gestation damages the developing regulatory microenvironment but not the hemopoietic stem cell population that it hosts. 12 refs., 1 fig., 4 tabs.

  14. Gamma irradiation: a method to produce an abiotic control for biological activated carbon.

    PubMed

    Stoquart, C; Vázquez-Rodríguez, G A; Servais, P; Barbeau, B

    2013-01-01

    The aim of this paper was to investigate the feasibility of using gamma irradiation to inhibit the microbial activity of biological powder activated carbon (PAC) without impacting its adsorptive properties. First of all, the range of dose of gamma rays required to produce abiotic PAC was selected on the basis of heterotrophic plate counts (HPC) inactivation and methylene blue (MB) adsorption kinetics. Doses inferior to 10 kGy were not sufficient to inhibit the culture of heterotrophic bacteria. On the other hand, doses superior to 15 kGy were demonstrated to affect the adsorption rate of MB. Consequently, a dose comprised between 10 and 15 kGy was selected for further investigation. In order to validate the adequacy of the range of dose (i.e. 10-15 kGy), adsorption characteristics were tested by monitoring the removal kinetics of refractory dissolved organic carbon (RDOC). No significant differences were observed between irradiated and non-irradiated biological PAC for the adsorption of RDOC. Irradiated, non-irradiated and virgin PAC were also evaluated in terms of abundance of viable (using the LIVE/DEAD BacLight method) bacteria and in terms of heterotrophic biomass activity. The results of the BacLight method demonstrated that attachment of the biofilm on the PAC was not impacted by the irradiation and heterotrophic activity measurements demonstrated that the latter could be radically reduced in the range of dose selected. In conclusion, when using a proper dose, the gamma irradiation of colonized activated carbon drastically reduced the heterotrophic activity on activated carbon without significantly impacting its adsorptive behaviour.

  15. Wood-Polymer composites obtained by gamma irradiation

    SciTech Connect

    Gago, J.; Lopez, A.; Rodriguez, J.; Santiago, J.; Acevedo, M.

    2007-10-26

    In this work we impregnate three Peruvian woods (Calycophy spruceanum Be, Aniba amazonica Meiz and Hura crepitans L) with styrene-polyester resin and methyl methacrylate. The polymerization of the system was promoted by gamma radiation and the experimental optimal condition was obtained with styrene-polyester 1:1 and 15 kGy. The obtained composites show reduced water absorption and better mechanical properties compared to the original wood. The structure of the wood-polymer composites was studied by light microscopy. Water absorption and hardness were also obtained.

  16. The contract facilities for gamma irradiation at Dagneux, France

    NASA Astrophysics Data System (ADS)

    Pellerin, D.; Kavanagh, M. T.

    CONSERVATOME SA have operated a facility at DAGNEUX near LYON, France since 1961. This operation is among the very first of its kind in the entire world. The process is based on gamma rays from Cobalt 60 of which there are three separate units. In addition there is a small experimental unit using Cesium 137. At present CONSERVATOME is owned by TRANSNUCLEAIRE and EPICEA as principal shareholders and so has the support of the French Atomic Energy Commission. This paper describes the larger D3 unit and reviews some of the products treated at DAGNEUX.

  17. Effects of gamma irradiation and repetitive freeze-thaw cycles on the biomechanical properties of human flexor digitorum superficialis tendons.

    PubMed

    Ren, Dejie; Sun, Kang; Tian, Shaoqi; Yang, Xu; Zhang, Cailong; Wang, Wenhao; Huang, Hongjie; Zhang, Jihua; Deng, Yujie

    2012-01-10

    An increasing number of tissue banks have begun to focus on gamma irradiation and freeze-thaw in the reconstruction of anterior cruciate ligaments using allografts. The purpose of this study was to evaluate the biomechanical properties of human tendons after exposure to gamma radiation and repeated freeze-thaw cycles and to compare them with fresh specimens. Forty flexor digitorum superficialis tendons were surgically procured from five fresh cadavers and divided into four groups: fresh tendon, gamma irradiation, freeze-thaw and gamma irradiation+freeze-thaw. The dose of gamma irradiation was 25 kGy. Each freeze-thaw cycle consisted of freezing at -80 °C for 7 day and thawing at 25 °C for 6 h. These tendons underwent 4 freeze-thaw cycles. Biomechanical properties were analyzed during load-to-failure testing. The fresh tendons were found to be significantly different in ultimate load, stiffness and ultimate stress relative to the other three groups. The tendons of the gamma+freeze-thaw group showed a significant decrease in ultimate load, ultimate stress and stiffness compared with the other three groups. Gamma irradiation and repeated freezing-thawing (4 cycles) can change the biomechanical properties. However, no significant difference was found between these two processes on the effect of biomechanical properties. It is recommended that gamma irradiation (25 kGy) and repetitive freeze-thaw cycles (4 cycles) should not be adopted in the processing of the allograft tendons.

  18. Pretreatment with low-dose gamma irradiation enhances tolerance to the stress of cadmium and lead in Arabidopsis thaliana seedlings.

    PubMed

    Qi, Wencai; Zhang, Liang; Wang, Lin; Xu, Hangbo; Jin, Qingsheng; Jiao, Zhen

    2015-05-01

    Heavy metals are important environmental pollutants with negative impact on plant growth and development. To investigate the physiological and molecular mechanisms of heavy metal stress mitigated by low-dose gamma irradiation, the dry seeds of Arabidopsis thaliana were exposed to a Cobalt-60 gamma source at doses ranging from 25 to 150Gy before being subjected to 75µM CdCl2 or 500µM Pb(NO3)2. Then, the growth parameters, and physiological and molecular changes were determined in response to gamma irradiation. Our results showed that 50-Gy gamma irradiation gave maximal beneficial effects on the germination index and root length in response to cadmium/lead stress in Arabidopsis seedlings. The hydrogen peroxide and malondialdehyde contents in seedlings irradiated with 50-Gy gamma rays under stress were significantly lower than those of controls. The antioxidant enzyme activities and proline levels in the irradiated seedlings were significantly increased compared with the controls. Furthermore, a transcriptional expression analysis of selected genes revealed that some components of heavy metal detoxification were stimulated by low-dose gamma irradiation under cadmium/lead stress. Our results suggest that low-dose gamma irradiation alleviates heavy metal stress, probably by modulating the physiological responses and gene expression levels related to heavy metal resistance in Arabidopsis seedlings. PMID:25723134

  19. Mentha piperita as a pivotal neuro-protective agent against gamma irradiation induced DNA fragmentation and apoptosis : Mentha extract as a neuroprotective against gamma irradiation.

    PubMed

    Hassan, Hanaa A; Hafez, Hani S; Goda, Mona S

    2013-01-01

    Ionizing radiation is classified as a potent carcinogen, and its injury to living cells, in particular to DNA, is due to oxidative stress enhancing apoptotic cell death. Our present study aimed to characterize and semi-quantify the radiation-induced apoptosis in CNS and the activity of Mentha extracts as neuron-protective agent. Our results through flow cytometry exhibited the significant disturbance and arrest in cell cycle in % of M1: SubG1 phase, M2: G0/1 phase of diploid cycle, M3: S phase and M4: G2/M phase of cell cycle in brain tissue (p < 0.05). Significant increase in % of apoptosis and P53 protein expression as apoptotic biomarkers were coincided with significant decrease in Bcl(2) as an anti-apoptotic marker. The biochemical analysis recorded a significant decrease in the levels of reduced glutathione, superoxide dismutase, deoxyribonucleic acid (DNA) and ribonucleic acid contents. Moreover, numerous histopathological alterations were detected in brain tissues of gamma irradiated mice such as signs of chromatolysis in pyramidal cells of cortex, nuclear vacuolation, numerous apoptotic cell, and neural degeneration. On the other hand, gamma irradiated mice pretreated with Mentha extract showed largely an improvement in all the above tested parameters through a homeostatic state for the content of brain apoptosis and stabilization of DNA cycle with a distinct improvement in cell cycle analysis and antioxidant defense system. Furthermore, the aforementioned effects of Mentha extracts through down-regulation of P53 expression and up-regulation of Bcl(2) domain protected brain structure from extensive damage. Therefore, Mentha extract seems to have a significant role to ameliorate the neuronal injury induced by gamma irradiation.

  20. Gamma irradiation of peanut kernel to control mold growth and to diminish aflatoxin contamination

    NASA Astrophysics Data System (ADS)

    Y.-Y. Chiou, R.

    1996-09-01

    Peanut kernel inoculated with Aspergillus parasiticus conidia were gamma irradiated with 0, 2.5, 5.0 and 10 kGy using Co60. Levels higher than 2.5 kGy were effective in retarding the outgrowth of A. parasiticus and reducing the population of natural mold contaminants. However, complete elimination of these molds was not achieved even at the dose of 10 kGy. After 4 wk incubation of the inoculated kernels in a humidified condition, aflatoxins produced by the surviving A. parasiticus were 69.12, 2.42, 57.36 and 22.28 μ/g, corresponding to the original irradiation levels. Peroxide content of peanut oils prepared from the irradiated peanuts increased with increased irradiation dosage. After storage, at each irradiation level, peroxide content in peanuts stored at -14°C was lower than that in peanuts stored at an ambient temperature. TBA values and CDHP contents of the oil increased with increased irradiation dosage and changed slightly after storage. However, fatty acid contents of the peanut oil varied in a limited range as affected by the irradiation dosage and storage temperature. The SDS-PAGE protein pattern of peanuts revealed no noticeable variation of protein subunits resulting from irradiation and storage.

  1. Combined effects of gamma-irradiation and modified atmosphere packaging on quality of some spices.

    PubMed

    Kirkin, Celale; Mitrevski, Blagoj; Gunes, Gurbuz; Marriott, Philip J

    2014-07-01

    Thyme (Thymus vidgaris L.), rosemary (Rosmarinus officinalis L.), black pepper (Piper nigrum L.) and cumin (Cuminum cyminum L.) in ground form were packaged in either air or 100% N2 and γ-irradiated at 3 different irradiation levels (7kGy, 12kGy, 17kGy). Total viable bacterial count, yeast and mould count, colour, essential oil yield and essential oil composition were determined. Microbial load was not detectable after 12kGy irradiation of all samples. Irradiation resulted in significant changes in colour values of rosemary and black pepper. The discolouration of the irradiated black pepper was lower in modified atmosphere packaging (MAP) compared to air packaging. Essential oil yield of irradiated black pepper and cumin was lower in air packaging compared to MAP. Gamma-irradiation generally decreased monoterpenes and increased oxygenated compounds, but the effect was lower in MAP. Overall, spices should be irradiated under an O2-free atmosphere to minimise quality deterioration. PMID:24518340

  2. Inhibitory effect of gamma irradiation and its application for control of postharvest green mold decay of Satsuma mandarins.

    PubMed

    Jeong, Rae-Dong; Chu, Eun-Hee; Lee, Gun Woong; Cho, Chuloh; Park, Hae-Jun

    2016-10-01

    Gamma irradiation has been shown to be effective for the control of postharvest fungi in vitro, but little is known regarding antifungal action, responses to gamma irradiation, and its application to fresh produce. Gamma irradiation was evaluated for its in vitro and in vivo antifungal activity against Penicillium digitatum on Satsuma mandarin fruits. Green mold was inhibited in a dose-dependent manner. Gamma irradiation showed a complete inhibition of spore germination, germ tube elongation, and mycelial growth of P. digitatum, particularly at 1.0kGy. To further investigate the mechanisms by which gamma irradiation inhibits fungal growth, the membrane integrity and cellular leakage of conidia were tested, indicating that gamma irradiation results in the loss of plasma membrane integrity, causing the release of intracellular contents such as soluble proteins. In vivo assays demonstrated that established doses can completely inhibit the growth of fungal pathogens, but such high doses cause severe fruit damage. Thus, to eliminate the negative impact on fruit quality, gamma irradiation at lower doses was evaluated for inhibition of P. digitatum, in combination with a chlorine donor, sodium dichloro-s-triazinetrione (NaDCC). Interestingly, only a combined treatment with 0.4kGy of gamma irradiation and 10ppm of NaDCC exhibited significant synergistic antifungal activity against green mold decay. The mechanisms by which the combined treatment decreased the green mold decay of mandarin fruits can be directly associated with the disruption of cell membrane of the fungal pathogen, which resulted in a loss of cytoplasmic material from the hyphae. These findings suggest that a synergistic effect of combining treatment with gamma irradiation with NaDCC has potential as an antifungal approach to reduce the severity of green mold in mandarin fruits.

  3. Inhibitory effect of gamma irradiation and its application for control of postharvest green mold decay of Satsuma mandarins.

    PubMed

    Jeong, Rae-Dong; Chu, Eun-Hee; Lee, Gun Woong; Cho, Chuloh; Park, Hae-Jun

    2016-10-01

    Gamma irradiation has been shown to be effective for the control of postharvest fungi in vitro, but little is known regarding antifungal action, responses to gamma irradiation, and its application to fresh produce. Gamma irradiation was evaluated for its in vitro and in vivo antifungal activity against Penicillium digitatum on Satsuma mandarin fruits. Green mold was inhibited in a dose-dependent manner. Gamma irradiation showed a complete inhibition of spore germination, germ tube elongation, and mycelial growth of P. digitatum, particularly at 1.0kGy. To further investigate the mechanisms by which gamma irradiation inhibits fungal growth, the membrane integrity and cellular leakage of conidia were tested, indicating that gamma irradiation results in the loss of plasma membrane integrity, causing the release of intracellular contents such as soluble proteins. In vivo assays demonstrated that established doses can completely inhibit the growth of fungal pathogens, but such high doses cause severe fruit damage. Thus, to eliminate the negative impact on fruit quality, gamma irradiation at lower doses was evaluated for inhibition of P. digitatum, in combination with a chlorine donor, sodium dichloro-s-triazinetrione (NaDCC). Interestingly, only a combined treatment with 0.4kGy of gamma irradiation and 10ppm of NaDCC exhibited significant synergistic antifungal activity against green mold decay. The mechanisms by which the combined treatment decreased the green mold decay of mandarin fruits can be directly associated with the disruption of cell membrane of the fungal pathogen, which resulted in a loss of cytoplasmic material from the hyphae. These findings suggest that a synergistic effect of combining treatment with gamma irradiation with NaDCC has potential as an antifungal approach to reduce the severity of green mold in mandarin fruits. PMID:27356109

  4. Free radicals properties of gamma-irradiated penicillin-derived antibiotics: piperacillin, ampicillin, and crystalline penicillin.

    PubMed

    Wilczyński, Sławomir; Pilawa, Barbara; Koprowski, Robert; Wróbel, Zygmunt; Ptaszkiewicz, Marta; Swakoń, Jan; Olko, Paweł

    2014-03-01

    The aim of this work was to determine the concentrations and properties of free radicals in piperacillin, ampicillin, and crystalline penicillin after gamma irradiation. The radicals were studied by electron paramagnetic resonance (EPR) spectroscopy using an X-band spectrometer (9.3 GHz). Gamma irradiation was performed at a dose of 25 kGy. One- and two-exponential functions were fitted to the experimental data, in order to assess the influence of the antibiotics' storage time on the measured EPR lines. After gamma irradiation, complex EPR lines were recorded confirming the presence of a large number of free radicals formed during the irradiation. For all tested antibiotics, concentrations of free radicals and parameters of EPR spectra changed with storage time. The results obtained demonstrate that concentration of free radicals and other spectroscopic parameters can be used to select the optimal parameters of radiation sterilization of β-lactam antibiotics. The most important parameters are the constants τ (τ (1(A),(I)) and τ (2(A),(I))) and K (K (0(A),(I)), K (1(A),(I)), K (2(A),(I))) of the exponential functions that describe free radicals decay during samples storage.

  5. EPR investigation of gamma irradiated single crystal guaifenesin: A combined experimental and computational study

    NASA Astrophysics Data System (ADS)

    Tasdemir, Halil Ugur; Sayin, Ulku; Türkkan, Ercan; Ozmen, Ayhan

    2016-04-01

    Gamma irradiated single crystal of Guaifenesin (Glyceryl Guaiacolate), an important expectorant drug, were investigated with Electron Paramagnetic Resonance (EPR) spectroscopy between 123 and 333 K temperature at different orientations in the magnetic field. Considering the chemical structure and the experimental spectra of the gamma irradiated single crystal of guaifenesin sample, we assumed that alkoxy or alkyl-type paramagnetic species may be produced by irradiation. Depending on this assumption, eight possible alkoxy and alkyl-type radicals were modeled and EPR parameters of these modeled radicals were calculated using the B3LYP/6-311++G(d,p)-level of density functional theory (DFT). Theoretically calculated values of alkyl-type modeled radical(R3) are in good agreement with experimentally determined EPR parameters of single crystal. Furthermore, simulation spectra which are obtained by using the theoretical initial values are well matched with the experimental spectra. It was determined that a stable Cα •H2αCβHβCγH2γ (R3) alkyl radical was produced in the host crystal as a result of gamma irradiation.

  6. Optical and rheological study of gamma irradiated rare-earth nanoparticle based ferrofluids

    NASA Astrophysics Data System (ADS)

    Paul, Nibedita; Mohanta, Dambarudhar; Saha, Abhijit

    2012-12-01

    The present work reports on the optical and rheological properties of unexposed and gamma irradiated rare-earth (RE) oxide nanoparticle-based ferrofluids (FF). The ferrofluids were prepared by dispersing surfactant coated gadolinium oxide (Gd2O3) nanoparticles in ethanol medium and later on subjected to energetic gamma irradiation (1.25 MeV) at select doses. As predicted from transmission electron microscopy and X-ray diffraction (XRD) studies, the synthesized nanoparticles are of ˜7 nm size which crystallize into cubic crystal structure. The photoluminescence response reveals creation of defect states on nanoparticle surfaces when FFs are subjected to gamma irradiation. Whereas, rheology measurements showed unusual shear thinning behavior of the ferrofluids. The flow behavior of all the samples can be correlated to the bi-exponential decay curve fitting which reveals that decay phenomenon is governed by two independent mechanism: fast and slow events. The variation of the decay parameter with irradiation dose is attributed to the creation of point defects and weakening of inter nanoparticle bonding.

  7. Stability of the GaAs based Hall sensors irradiated by gamma quanta

    NASA Astrophysics Data System (ADS)

    Gradoboev, A. V.; Karlova, G. F.

    2015-04-01

    The present work is aimed at investigation of the stability of the GaAsbased Hall sensors (pickups) to irradiation by gamma quanta. The examined objects are the gallium arsenide based Hall sensors manufactured on thin active layers by the methods of vaporphase epitaxy (VPE), molecular beam epitaxy, and ion implantation. Our research methodology involves measurements of the volt-ampere characteristics (VACs) of all sensors for different values of the supply voltage polarity and electron concentration and mobility by the Van-der- Pau method as well as investigations of the noise properties of the sensors before and after irradiation. The sensors are irradiated by gamma quanta of Co60 at room temperature in the passive mode, that is, without imposition of an electrical bias. As a result of investigations, it is established that a part of the active layer of finite thickness adjoining the substrate plays an important role in the charge carrier transmission process depending on the concentration of deep-level centers in the substrate. Irradiation by high doses leads to degradation of VACs and increase in the spectral density of the sensor noise. Low gamma radiation doses have a stabilization effect on the sensors. Periodic relaxation processes are observed for a part of the structures manufactured by the VPE method. The assumption is made that they can be caused by the deep-level centersin GaAs.

  8. Effect of gamma irradiation on the structural properties and diffusion coefficient in Co-Zn ferrite

    NASA Astrophysics Data System (ADS)

    Hemeda, O. M.; El-Saadawy, M.

    2003-01-01

    A series of samples of Co 1- xZn xFe 2O 4 were prepared by the usual ceramic technique where x=0.3,0.5,0.6, and 0.8. The samples were irradiated by Co 60 gamma source with a high dose equal to 10 6 rad/h. The diffusion coefficient of oxygen vacancies was estimated from DC conductivity measurements. It was noticed that the diffusion coefficient increased after gamma irradiation for all Zn 2+ concentrations. This could be explained on the basis of displacement of metal ions from its original sites under the effect of irradiation leaving behind it lattice vacancies which increase the diffusion coefficient. The concentration of lattice vacancies increased, whereas the activation energy of diffusion process decreased after irradiation. The lattice parameter of the studied samples increased due to the formation of ferrous ions under the ionizing effect of gamma radiation. These changes in some physical properties of the studied samples are useful for the detection of nuclear contamination of environmental atmosphere.

  9. Effect of gamma irradiation on hyperthermal composting microorganisms for feasible application in space

    NASA Astrophysics Data System (ADS)

    Yoon, Minchul; Choi, Jong-il; Yamashita, Masamichi

    2013-05-01

    The composting system is the most efficient method for processing organic waste in space; however, the composting activity of microorganisms can be altered by cosmic rays. In this study, the effect of ionizing irradiation on composting bacteria was investigated. Sequence analyses of amplified 16S rRNA, 18S rRNA, and amoA genes were used to identify hyperthermal composting microorganisms. The viability of microorganisms in compost soil after gamma irradiation was directly determined using LIVE/DEAD BacLight viability kit. The dominant bacterial genera were Weissella cibaria and Leuconostoc sp., and the fungal genera were Metschnikowia bicuspidata and Pichia guilliermondii. Gamma irradiation up to a dose of 10 kGy did not significantly alter the microbial population. Furthermore, amylase and cellulase activities were maintained after high-dose gamma irradiation. Our results show that hyperthermal microorganisms can be used to recycle agricultural and fermented material in space stations and other human-inhabiting facilities on the Moon, Mars, and other planets.

  10. The effects of gamma-ray irradiation on organic materials of different conjugation lengths

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng; Taylor, Edward W.

    2009-08-01

    The radiation resistance of organic electro-optic and optoelectronic materials of different conjugation lengths for space applications is receiving increased attention. Earlier investigation reported that guest-host (G-H) poled polymer EO modulator devices composed of a phenyltetraene bridge-type chromophore in amorphous polycarbonate (CLD/APC) did not exhibit a decrease in EO response (i.e., an increase in modulation-switching voltage- Vπ) following irradiation by low dose [10-160 krad(Si)] 60Co gamma-rays. In this work, the post-irradiation responses of 60Co gamma-rays on CLD1/APC thin films are examined by various chemical and spectroscopic methods including: a solubility test, thin-layer chromatography, proton nuclear magnetic resonance spectroscopy, UV-vis absorption, and infra-red absorption. The results indicate that CLD1 and APC did not decompose under gamma-ray irradiation at dose levels ranging from 66-274 krad(Si) and from 61-154 krad(Si), respectively which support the previously reported data. A comparison with an in situ proton irradiated DRI/PMMA material is also presented.

  11. Gamma irradiation induced disintegration of waste activated sludge for biological hydrogen production

    NASA Astrophysics Data System (ADS)

    Yin, Yanan; Wang, Jianlong

    2016-04-01

    In this paper, gamma irradiation was applied for the disintegration and dissolution of waste activated sludge produced during the biological wastewater treatment, and the solubilized sludge was used as substrate for bio-hydrogen production. The experimental results showed that the solubilization of waste activated sludge was 53.7% at 20 kGy and pH=12, and the SCOD, polysaccharides, protein, TN and TP contents in the irradiated sludge solutions was 3789.6 mg/L, 268.3 mg/L, 1881.5 mg/L, 132.3 mg/L and 80.4 mg/L, respectively. The irradiated sludge was used for fermentative hydrogen production, and the hydrogen yield was 10.5±0.7 mL/g SCODconsumed. It can be concluded that the irradiated waste activated sludge could be used as a low-cost substrate for fermentative hydrogen production.

  12. Interaction of oxidation and crosslinking in gamma-irradiated ultrahigh molecular-weight polyethylene.

    PubMed

    Shen, Fu-Wen; McKellop, Harry A

    2002-09-01

    The interaction between oxidation and crosslinking in gamma-irradiated ultrahigh molecular-weight polyethylene with and without artificial aging was studied. The effect of the atmosphere during irradiation (air vs. low oxygen) occurred primarily within about 0.5 mm of the surface, that is, the depth to which oxygen had diffused when the polyethylene specimen was machined and when it was irradiated. Irradiation in the presence of oxygen induced oxidation instead of crosslinking, so that the level of crosslinking achieved was lower than that which normally would occur at the same dose in the absence of oxygen. Subsequent artificial aging reduced the gel content (crosslinking) and had a maximal effect on the surface and subsurface regions for the gamma-air and gamma-low oxygen polyethylenes, respectively. Thus the storage environments and durations prior to irradiation and prior to artificial aging must be taken into account when attempting to duplicate the oxidation-crosslinking profiles that occur with actual implants in clinical use. In addition, the oxidation mechanisms initiated by the artificial aging method used in this study (i.e., heating in air to 80 degrees C) initiated somewhat different oxidative reactions from those that occur during prolonged shelf life at room temperature or in vivo. In particular, the formation of a peak of oxidation below the free surface of the polyethylene is due to the combined effects of the distribution of residual free radicals and the diffusion gradient of the oxygen. The interactive relationship between oxidation and crosslinking characterized in the present study provides a fundamental basis for understanding the wear behavior of gamma-sterilized components in past clinical use. It also provides guidelines for the development of polyethylenes with improved resistance to oxidation and wear, with particular relevance to estimation of the amount of crosslinking need- ed to potentially eliminate the clinical problem of

  13. Microbial analysis and survey test of gamma-irradiated freeze-dried fruits for patient's food

    NASA Astrophysics Data System (ADS)

    Park, Jae-Nam; Sung, Nak-Yun; Byun, Eui-Hong; Byun, Eui-Baek; Song, Beom-Seok; Kim, Jae-Hun; Lee, Kyung-A.; Son, Eun-Joo; Lyu, Eun-Soon

    2015-06-01

    This study examined the microbiological and organoleptic qualities of gamma-irradiated freeze-dried apples, pears, strawberries, pineapples, and grapes, and evaluated the organoleptic acceptability of the sterilized freeze-dried fruits for hospitalized patients. The freeze-dried fruits were gamma-irradiated at 0, 1, 2, 3, 4, 5, 10, 12, and 15 kGy, and their quality was evaluated. Microorganisms were not detected in apples after 1 kGy, in strawberries and pears after 4 kGy, in pineapples after 5 kGy, and in grapes after 12 kGy of gamma irradiation. The overall acceptance score, of the irradiated freeze-dried fruits on a 7-point scale at the sterilization doses was 5.5, 4.2, 4.0, 4.1, and 5.1 points for apples, strawberries, pears, pineapples, and grapes, respectively. The sensory survey of the hospitalized cancer patients (N=102) resulted in scores of 3.8, 3.7, 3.9, 3.9, and 3.7 on a 5-point scale for the gamma-irradiated freeze-dried apples, strawberries, pears, pineapples, and grapes, respectively. The results suggest that freeze-dried fruits can be sterilized with a dose of 5 kGy, except for grapes, which require a dose of 12 kGy, and that the organoleptic quality of the fruits is acceptable to immuno-compromised patients. However, to clarify the microbiological quality and safety of freeze-dried fruits should be verified by plating for both aerobic and anaerobic microorganisms.

  14. Stimulatory Effects of Gamma Irradiation on Phytochemical Properties, Mitotic Behaviour, and Nutritional Composition of Sainfoin (Onobrychis viciifolia Scop.)

    PubMed Central

    Mat Taha, Rosna; Lay, Ma Ma; Khalili, Mahsa

    2014-01-01

    Sainfoin (Onobrychis viciifolia Scop. Syn. Onobrychis sativa L.) is a bloat-safe forage crop with high levels of tannins, which is renowned for its medicinal qualities in grazing animals. Mutagenesis technique was applied to investigate the influence of gamma irradiation at 30, 60, 90, and 120 Gy on mitotic behavior, in vitro growth factors, phytochemical and nutritional constituents of sainfoin. Although a percentage of plant necrosis and non-growing seed were enhanced by irradiation increment, the germination speed was significantly decreased. It was observed that gamma irradiated seeds had higher value of crude protein and dry matter digestibility compared to control seeds. Toxicity of copper was reduced in sainfoin irradiated seeds at different doses of gamma rays. Anthocyanin content also decreased in inverse proportion to irradiation intensity. Accumulation of phenolic and flavonoid compounds was enhanced by gamma irradiation exposure in leaf cells. HPLC profiles differed in peak areas of the two important alkaloids, Berberine and Sanguinarine, in 120 Gy irradiated seeds compared to control seeds. There were positive correlations between irradiation dose and some abnormality divisions such as laggard chromosome, micronucleus, binucleated cells, chromosome bridge, and cytomixis. In reality, radiocytological evaluation was proven to be essential in deducing the effectiveness of gamma irradiation to induce somaclonal variation in sainfoin. PMID:25147870

  15. Postharvest Disease Control of Colletotrichum gloeosporioides and Penicillium expansum on Stored Apples by Gamma Irradiation Combined with Fumigation

    PubMed Central

    Cheon, Wonsu; Kim, Young Soo; Balaraju, Kotnala; Kim, Bong-Su; Lee, Byeong-Ho; Jeon, Yongho

    2016-01-01

    To study the control of postharvest decay caused by Colletotrichum gloeosporioides and Penicillium expansum, gamma irradiation alone or in combination with fumigation was evaluated to extend the shelf life of apples in South Korea. An irradiation dose of 2.0 kGy resulted in the maximum inhibition of C. gloeosporioides and P. expansum spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.22 and 0.35 kGy for C. gloeosporioides and P. expansum, respectively. Microscopic observations revealed that when the fungal spores were treated with gamma irradiation (4.0 kGy), conidial germination was stopped completely resulting in no germ tube formation in C. gloeosporioides. Treatment with the eco-friendly fumigant ethanedinitrile had a greater antifungal activity against C. gloeosporioides and P. expansum in comparison with the non-treated control under in vitro conditions. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments to control postharvest decay on stored apples. Interestingly, when apples were treated with gamma irradiation in combined with fumigation, disease inhibition increased more at lower (< 0.4 kGy) than at higher doses of irradiation, suggesting that combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions. PMID:27721696

  16. Application of gamma irradiation for aging control and improvement of shelf-life of kimchi, korean salted and fermented vegetables

    NASA Astrophysics Data System (ADS)

    Song, Hyun-Pa; Kim, Dong-Ho; Yook, Hong-Sun; Kim, Kyung-Soo; Kwon, Joong-Ho; Byun, Myung-Woo

    2004-09-01

    This study was carried out to evaluate the application of food irradiation as a method for extending shelf life of Kimchi. Gamma irradiation up to 10 kGy in the early stage of Kimchi fermentation had a dose-dependent effect on the inactivation of fermentative microbes, lowering the lactate dehydrogenase (LDH) activity and delaying acidification. Although gamma irradiation on the mid-fermentation stage of Kimchi inactivated the fermentative microbes effectively, LDH activity remained high and acidification continued. Kimchi irradiated at 10 kGy had lower scores in acceptability than those of control, 2.5 and 5 kGy irradiated. Therefore, gamma irradiation upto 5 kGy in the early fermentation stage is recommended for aging control and the improvement of shelf life of Kimchi.

  17. Synergistic effect of mixed neutron and gamma irradiation in bipolar operational amplifier OP07

    NASA Astrophysics Data System (ADS)

    Yan, Liu; Wei, Chen; Shanchao, Yang; Xiaoming, Jin; Chaohui, He

    2016-09-01

    This paper presents the synergistic effects in bipolar operational amplifier OP07. The radiation effects are studied by neutron beam, gamma ray, and mixed neutron/gamma ray environments. The characterateristics of the synergistic effects are studied through comparison of different experiment results. The results show that the bipolar operational amplifier OP07 exhibited significant synergistic effects in the mixed neutron and gamma irradiation. The bipolar transistor is identified as the most radiation sensitive unit of the operational amplifier. In this paper, a series of simulations are performed on bipolar transistors in different radiation environments. In the theoretical simulation, the geometric model and calculations based on the Medici toolkit are built to study the radiation effects in bipolar components. The effect of mixed neutron and gamma irradiation is simulated based on the understanding of the underlying mechanisms of radiation effects in bipolar transistors. The simulated results agree well with the experimental data. The results of the experiments and simulation indicate that the radiation effects in the bipolar devices subjected to mixed neutron and gamma environments is not a simple combination of total ionizing dose (TID) effects and displacement damage. The data suggests that the TID effect could enhance the displacement damage. The synergistic effect should not be neglected in complex radiation environments.

  18. Effect of. gamma. -ray irradiation on sugar production from plant biomass

    SciTech Connect

    Han, Y.W.; Ciegler, A.

    1982-01-01

    During the past several years, evidence has indicated the effectiveness of gamma radiation in altering lignocellulosic polymers to enhance their susceptibility to chemical and enzymatic attack. Reassessment of high-energy radiation as a tool in reducing the use of fossil fuel suggested that the procedure might have practical value in modification of lignocellulosics prior to hydrolysis to sugars for use in fermentation. Select combinations of chemical pretreatment and gamma radiation can also lead to production of feedstocks useful to the chemical synthesis industry. Preliminary research indicated that the properties of lignocellulosics are changed and a variety of compounds are produced by gamma irradiation. In general, gamma irradiation of lignocellulosics such as wood, paper, and crop residues causes depolymerization of biopolymers and decomposition of carbohydrates at dosages between 10 and 100 Mrad, and the resulting materials shows a loss of crystallinity and increase in digestibility by subsequent hydrolysis by acid and enzymes. These changes may be advantageously used for production of energy from biomass. Large quantities of gamma-emitting /sup 137/Cs are found in fission-product wastes stored since the initiation of /sup 239/Pu production during World War II. The task of disposing of the radioactive wastes produced by nuclear power plants is often cited as one of the principal drawbacks to the use of nuclear fission for electric power generation. 1 figure, 3 tables.

  19. Structural and optical modifications in gamma-irradiated polyimide/silica nanocomposite

    NASA Astrophysics Data System (ADS)

    Nouh, S. A.; Tommalieh, M. J.; El-Shamy, N. T.

    2015-06-01

    The structural and optical properties of thin films of polyimide composites with nanosilica particle content of 15 wt%, prepared via sol-gel process, were studied as a function of the gamma dose. The resultant effect of gamma irradiation on the properties of polyimide/silica nanocomposite has been investigated using X-ray diffraction and UV spectroscopy. Absorption and reflectance spectra were collected by a spectrophotometer giving UV-radiation of wavelength range 200-800 nm. The optical data obtained were analyzed and the calculated values of the optical energy gap exhibited gamma dose dependence. The direct optical energy gap for the nonirradiated polyimide/silica nanocomposite is about 2.41 eV, and increases to a value of 2.65 eV when irradiated with gamma doses up to 300 kGy. It was found that the calculated refractive index of the polyamide/silica increases with the gamma dose in the range 50-300 kGy.

  20. Gamma-Ray Irradiation and Contact with High-Alkalinity Sludge: Stability Studies of Mercury Fulminate

    SciTech Connect

    Fondeur, F.F.; Wilmarth, W.R.; Peters, T.B.; Fink, S.D

    2005-09-15

    The stability of mercury fulminate under gamma-ray irradiation and in a high-alkalinity sludge environment was determined. Both differential scanning calorimetry and Fourier transform infrared spectroscopy were used to characterize mercury fulminate. Mercury fulminate completely decomposed in a gamma-ray source (0.86 Mrad/h) after a dose of 208 Mrad. This exposure equates to {approx}2.4 to 4 yr in Savannah River Site tanks. Mercury fulminate decomposed in contact with high-alkalinity wet sludge. This study suggests that any mercury fulminate or closely related energetic species decomposed long ago if it ever formed in the tank farm.

  1. Gamma irradiation of sun-dried apricots ( Prunus armeniaca L.) for quality maintenance and quarantine purposes

    NASA Astrophysics Data System (ADS)

    Hussain, Peerzada R.; Meena, Raghuveer S.; Dar, Mohd A.; Wani, Ali M.

    2011-07-01

    The study is aimed at the optimization of gamma irradiation treatment of sun-dried apricots for quality maintenance and quarantine purposes. Sun-dried apricots pre-treated with potassium meta-bisulphite (KMS) at 2.5% w/v were procured from progressive apricot grower of district Kargil, Ladakh region of Jammu and Kashmir state. The sun-dried apricots were packed in 250 gauge polyethylene packs and gamma irradiated in the dose range 1.0-3.0 kGy. The gamma irradiated fruit including control was stored under ambient (15±2-25±2 °C, RH 70-80%) conditions and periodically evaluated for physico-chemical, sensory and microbial quality parameters. Radiation treatment at dose levels of 2.5 and 3.0 kGy proved significantly ( p≤0.05) beneficial in retention of higher levels of β-carotene, ascorbic acid, total sugars and color values without impairing the taste as perceived by the sensory panel analysists. The above optimized doses retained the β-carotene content of sun-dried apricots to the extent of 71.2% and 72.6% compared to 63.9% in control samples after 18 months of storage. Irradiation treatment facilitated the release of residual sulfur dioxide in KMS pre-treated sun-dried apricots significantly ( p≤0.05) below the prescribed limit for dried products. During storage, two-fold decrease in sulfur dioxide content was recorded in irradiated samples (3.0 kGy) as compared to 16.9% in control. The above optimized doses besides maintaining the higher overall acceptability of sun-dried apricots resulted in 5 log reductions in microbial load just after irradiation and 1.0 and 1.3 log reductions in yeast and mold and bacterial count after 18 months of ambient storage.

  2. Effect of gamma irradiation on nutritional value of dry field beans (Phaseolus vulgaris) for chicks.

    PubMed

    Reddy, S J; Pubols, M H; McGinnis, J

    1979-07-01

    The effect of gamma irradiation (60Co) of different varieties and breeding lines of dry field beans (Phaseolus vulgaris) on chick growth was determined using a chick growth assay in which the diet contained approximately 50% beans. Total protein (N X 6.25) in beans was not changed appreciably by irradiation (21 Mrad) but protein solubility in water was decreased. Irradiation increased in vitro enzymatic digestibility of bean protein by pepsin and by a mixture of trypsin, chymotrypsin and peptidase. In the bioassay the diet was formulated to derive half of the total protein (22.6%) from beans. Autoclaved Pinto and Pink beans gave significantly better growth than Red Mexican and White Pea beans. The differences between Red Mexican and White Pea beans were not significant except for Red Mexican breeding line number RS-59. The nutritional value of all varieties of beans, based on chick growth, was significantly improved by gamma irradiation. The irradiation treatment of beans tended to increase nitrogen retention by chicks and decrease uric acid nitrogen excretion in relation to nitrogen intake. PMID:448472

  3. Effect of gamma irradiation on molecular structure and physicochemical properties of corn starch.

    PubMed

    Chung, H-J; Liu, Q

    2009-06-01

    Carboxyl content and amylose leaching of gamma-irradiated corn starch increased and swelling factor decreased with increasing radiation dose. The apparent amylose content decreased gradually from 28.7% for native starch to 20.9% for 50 kGy irradiated starch. The proportion of short amylopectin branch chains (DP 6 to 12) increased, while the proportion of longer branch chains (DP > or = 37) decreased with increasing radiation dose. The relative crystallinity and the degree of granule surface order decreased from 28.5% and 0.631 in native starch to 26.9% and 0.605 in 50 kGy irradiated starch, respectively. Pasting viscosity and gelatinization temperatures decreased with an increase in radiation dose. At a high dose (50 kGy), melting of amylose-lipid complex in DSC thermogram was not observed. The rapidly digestible starch (RDS) content slightly decreased up to 10 kGy but increased at 50 kGy. The resistant starch (RS) content slightly decreased at 2 kGy and then increased up to 50 kGy. The slowly digestible starch (SDS) content showed the opposite trend to RS content. Slower irradiation dose rate reduced carboxyl content, swelling factor, and amylose leaching. The apparent amylose content and amylopectin chain length distribution were not significantly affected by dose rate of gamma irradiation. However, the relative crystallinity and gelatinization enthalpy increased with slower dose rate. Slower dose rate decreased RDS and SDS contents, and increased RS content.

  4. Resistance of a cultured fish cell line (CAF-MM1) to. gamma. irradiation

    SciTech Connect

    Mitani, H.; Etoh, H.; Egami, N.

    1982-02-01

    Fish are generally more resistant to whole-body ionizing radiation than mammals. To study the radiosensitivity of fish in vitro, CAF-MM1 cells derived from the fin of the goldfish, Carassius auratus, were used. The survival parameters of CAF-MM1 obtained after ..gamma.. irradiation at 26/sup 0/C were 325 rad for D/sub o/, 975 rad for Dq, and 15 for n. No mammalian cell line with such a low sensitivity in the presence of O/sub 2/ has been reported. It was found that the large initial shoulder of the survival curve was paralleled by substantial repair of sublethal damage as evidenced by split-dose experiments. This low sensitivity to ..gamma.. irradiation did not change upon the administration of caffeine or postirradiation illumination, although these treatments were effective after uv irradiation. The decrease in the mitotic index in CAF-MM1 occurred immediately after irradiation, and it recovered within a very short time. This indicated that the duration of G2 arrest was shorter than that observed in mammalian cells. The data also suggest that the resistance of fish to whole-body irradiation is attributable to resistance at the cellular level.

  5. Modification of the microstructure of the films formed by gamma irradiated starch examined by SEM

    NASA Astrophysics Data System (ADS)

    Cieśla, K.; Sartowska, B.

    2016-01-01

    The paper concerns the effect of gamma irradiation carried out for starch on the microstructure of the films prepared using the starch and its composition with sodium laurate (NaLau) and cetyltrimethylammonium bromide (CTAB) studied by scanning electron microscopy (SEM). Potato starch was irradiated with 60Co gamma rays applying a dose of 30 kGy. Films were prepared by the solution casting method with the addition of 30 wt% glycerol as a plasticizer. Films containing NaLau and CTAB were prepared after performing the procedure, leading to starch-surfactant complexes. Mechanical tests and wetting angle measurements were performed for the films. SEM observations were carried out for the surfaces, fractures and/or sections of the films subjected to chemical fixation and for the dried films. The films obtained using irradiated starch are characterized by a smoother and more homogeneous structure as compared to those based on the non-irradiated starch. Besides, a number of small precipitates were observed on the films surfaces after drying and the number of those precipitates seemed to be higher after irradiation. The results can be related to differences in the microstructure of gels formed on the intermediate step of the films preparation and to the presence of two phases in the system and might serve for explanation of the radiation induced improvement of the hydrophilic/hydrophobic properties, a modification of the mechanical properties of the films, as well as for the changes of those properties resulting after storage.

  6. Inactivation and fragmentation of lectin from Bothrops leucurus snake venom by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Nunes, E. S.; Souza, M. A. A.; Vaz, A. F. M.; Coelho, L. C. B. B.; Aguiar, J. S.; Silva, T. G.; Guarnieri, M. C.; Melo, A. M. M. A.; Oliva, M. L. V.; Correia, M. T. S.

    2012-04-01

    Gamma radiation alters the molecular structure of biomolecules and is able to mitigate the action of snake venoms and their isolated toxins. The effect of γ-radiation on the folding of Bothrops lecurus venom lectin was measured by a hemagglutinating assay, intrinsic and bis-ANS fluorescence. Intrinsic and bis-ANS fluorescence analyses indicated that irradiation caused unfolding followed by aggregation of the lectin. Our results suggest that irradiation can lead to significant changes in the protein structure, which may promote the loss of its binding property and toxic action.

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

    SciTech Connect

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

    2003-12-01

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

  8. Effect of crystalline structure on the infrared spectra of. gamma. irradiated cotton cellulose

    SciTech Connect

    Moharram, M.A.; Hakeem, N.A.

    1980-03-01

    The effect of crystalline modifications on the infrared spectra of ..gamma..-irradiated cotton cellulose is presented. The crystalline modifications were brought about by treating cotton material with an aqueous solution of NaOH of various concentrations. The infrared spectra of the irradiated samples indicate an absorption band corresponding to the absorption of C=O groups. It was found that the intensity and frequency of this band depend on the crystalline structure. Thus, it appears at 1735 cm/sup -1/ in the spectrum of cellulose I and at 1610 cm/sup -1/ in the spectrum of cellulose II.

  9. Characterization of the polymer-filler interface in (gamma)-irradiated silica-reinforced polysiloxane composites

    SciTech Connect

    Chien, A T; Balazs, B; LeMay, J

    2000-04-03

    The changes in hydrogen bonding at the interface of silica-reinforced polysiloxane composites due to aging in gamma radiation environments were examined in this study. Solvent swelling was utilized to determine the individual contributions of the matrix polymer and polymer-filler interactions to the overall crosslink density. The results show how the polymer-filler hydrogen bonding dominates the overall crosslink density of the material. Air irradiated samples displayed decreased hydrogen bonding at the polymer-filler interface, while vacuum irradiation revealed the opposite effect.

  10. The effects of lipid A on gamma-irradiated human peripheral blood lymphocytes in vitro

    NASA Astrophysics Data System (ADS)

    Dubničková, M.; Kuzmina, E. A.; Chausov, V. N.; Ravnachka, I.; Boreyko, A. V.; Krasavin, E. A.

    2016-03-01

    The modulatory effects of lipid A (diphosphoryl lipid A (DLA) and monophosphoryl lipid A (MLA)) on apoptosis induction and DNA structure damage (single and double-strand breaks (SSBs and DSBs, respectively)) in peripheral human blood lymphocytes are studied for 60Co gamma-irradiation. It is shown that in the presence of these agents the amount of apoptotic cells increases compared with the irradiated control samples. The effect is most strongly pronounced for DLA. In its presence, a significant increase is observed in the number of radiation-induced DNA SSBs and DSBs. Possible mechanisms are discussed of the modifying influence of the used agents on radiation-induced cell reactions

  11. Shellfish depuration by gamma irradiation. Progress report No. 1, October 1, 1985-July 25, 1986

    SciTech Connect

    Beghian, L.; Melnick, J.

    1986-07-25

    Objective is to investigate the feasibility of employing food irradiation technology to reduce or eliminate the threat of viral diseases contracted as a result of consumption of raw or inadequately cooked shellfish. Several recently published studies warn of the health risks associated with eating of raw shellfish - particularly American oysters, Crassostrea virginica, and the hardshelled clam, Mercenaria mercenaria. This study addresses the possibility of reducing the incidence of molluscanborne diseases through the application of /sup 60/Co gamma irradiation processing to effect the inactivation of pathogenic viruses in live, raw shwllfish. Dosimetry, D/sub 10/ doses, and organoleptic effects were studied.

  12. Study of gamma irradiation effect on positron annihilation mechanism in PFA

    NASA Astrophysics Data System (ADS)

    Yang, J.; Li, Z. X.; Zhao, B. Z.; Zhang, P.; Lu, E. Y.; Zhang, J.; Yuan, D. Q.; Cao, X. Z.; Yu, R. S.; Wang, B. Y.

    2014-03-01

    Gamma irradiation effect on annihilation characteristics of positronium and free positron in tetrafluoroethylene-perluoro (alkoxy vinyl ether) copolymer (PFA) were studied independently by age momentum correlation (AMOC) and the correlation between Doppler broadening S parameter and o-Ps fraction (S-Io-Ps correlation). AMOC results revealed decreases in S parameter of o-Ps, owing to accumulation of polar atoms around free volume. S-Io-Ps correlation indicated a reduced intrinsic S parameter of free positron in irradiated PFA, which was caused by enhanced positron trapping on polar atoms due to densification of local segments and variation in the elemental environment around free volumes.

  13. Effect of gamma irradiation on the wear behaviour of human tooth enamel

    NASA Astrophysics Data System (ADS)

    Qing, Ping; Huang, Shengbin; Gao, Shanshan; Qian, Linmao; Yu, Haiyang

    2015-06-01

    Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel.

  14. Effect of gamma irradiation on the wear behaviour of human tooth enamel

    PubMed Central

    Qing, Ping; Huang, Shengbin; Gao, ShanShan; Qian, LinMao; Yu, HaiYang

    2015-01-01

    Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel. PMID:26099692

  15. Detection of irradiated fresh fruits treated by e-beam or gamma rays

    NASA Astrophysics Data System (ADS)

    Marin-Huachaca, Nélida Simona; Lamy-Freund, Maria Tereza; Mancini-Filho, Jorge; Delincée, Henry; Villavicencio, Anna Lúcia C. H.

    2002-03-01

    Since about 1990, the amount of commercially irradiated food products available worldwide has increased. Commercial irradiation of foods has been allowed in Brazil since 1973 and now more than 20 different food products are approved. Among these products are a number of fresh fruits which may be irradiated for insect disinfestation, to delay ripening and to extend shelf-life. Today, there is a growing interest to apply radiation for the treatment of fruits instead of using fumigation or e.g. vapour-heat treatments, and an increased international trade in irradiated fruits is expected. To ensure free consumer choice, methods to identify irradiated foods are highly desirable. In this work, three detection methods for irradiated fruits have been employed: DNA Comet Assay, the half-embryo test and ESR. Both electron-beam (e-beam) and gamma rays were applied in order to compare the response with these two different kinds of radiation. Fresh fruits such as oranges, lemons, apples, watermelons and tomatoes were irradiated with doses in the range 0, 0.50, 0.75, 1.0, 2.0 and 4.0kGy. For analysis, the seeds of the fruits were utilized. Both DNA Comet Assay and the half-embryo test enabled an easy identification of the radiation treatment. However, under our conditions, ESR measurements were not satisfactory.

  16. Mutagenic effect by phenylalanine during gamma-irradiation of plasmid DNA in aqueous solution under oxic conditions.

    PubMed

    Reitsma-Wijker, C A; Slotman, B J; Lafleur, M V

    2000-11-01

    Irradiation of DNA in aqueous solution or in cells with gamma-rays results in different mutational spectra, indicating that in both situations different patterns of DNA damages are induced. One of the causes for these different types of damages might be the formation of secondary, organic radicals, if cells are irradiated. Some organic compounds, including the amino acid phenylalanine, are well known to produce radicals during irradiation. Under oxic conditions these secondary radicals react with oxygen, thus forming peroxyl radicals which can be very harmful to DNA, and which may, therefore, induce DNA damage leading to mutations. This study examines the influence of the presence of phenylalanine during gamma-irradiation of DNA in aqueous solution under oxic conditions. The results indicate that the formation of phenylalanine radicals influences the types of induced mutations in the gamma-radiation-induced mutation spectrum. The most prominent difference is the increase in G:C to T:A transversions and the decrease in G:C to A:T transitions in the presence of phenylalanine. Further, it appears that the gamma-radiation-induced mutation spectrum after irradiation of DNA in aqueous solution is more comparable to the intracellular gamma-radiation-induced mutation spectrum in E. coli cells, if phenylalanine is present during irradiation. Therefore, these results suggest that the presence of phenylalanine during irradiation of DNA in aqueous solution gives a better impression of gamma-radiation-induced mutations in bacterial systems than water only. PMID:11035161

  17. Gamma irradiation-induced effects on the electrical properties of HfO2-based MOS devices

    NASA Astrophysics Data System (ADS)

    Manikanthababu, N.; Arun, N.; Dhanunjaya, M.; Nageswara Rao, S. V. S.; Pathak, A. P.

    2016-02-01

    Hafnium Oxide (HfO2) thin films were synthesized by e-beam evaporation and Radio frequency magnetron sputtering techniques. Au/HfO2/Si-structured Metal Oxide Semiconductor capacitors have been fabricated to study the effects of gamma irradiation on the electrical properties, leakage current versus voltage (I-V) and capacitance versus voltage (C-V) characteristics, as a function of irradiation dose. Systematic increase in leakage current as well as accumulation capacitance has been observed with increase in the irradiation dose. The influence of gamma irradiation and pre-existing defects on the evolution of oxide and interface traps have been studied in detail.

  18. Effects of low-level gamma irradiation on the characteristics of fermented pork sausage during storage

    NASA Astrophysics Data System (ADS)

    Kim, I. S.; Jo, C.; Lee, K. H.; Lee, E. J.; Ahn, D. U.; Kang, S. N.

    2012-04-01

    The effect of gamma irradiation (0.5, 1, 2, and 4 kGy) on the quality of vacuum-packaged dry fermented sausages during refrigerated storage was evaluated. At Day 0 of irradiation, the pH, redness (CIE a*), yellowness (CIE b*), 2-thiobarbituric acid-reactive substances (TBARS) and volatile basic nitrogen (VBN) values of samples irradiated at 2 and 4 kGy were higher (p<0.05), but the CIE L* values (lightness) were lower than those of the non-irradiated control (p<0.05). At<1 kGy irradiation, however, the pH, CIE L*, CIE a* and CIE b*-value of samples were not significantly influenced by irradiation. The CIE a*, and CIE b*-values of samples irradiated at 2 and 4 kGy decreased with the increase of storage time. The VBN, TBARS, and CIE L*-values of samples irradiated at 4 kGy were not changed significantly during refrigerated storage for 90 days (p>0.05). The total plate counts (TPC) and lactic acid bacteria (LAB) in the samples irradiated at 4 kGy were significantly lower (p<0.01) than those with lower irradiation doses. At the end of storage, the TPC, coliform, and LAB in the samples were not increased after irradiation at 1, 0.5 and 1 kGy, respectively. TPC and LAB were not detected in samples irradiated at 4 kGy at Day 90. In addition, no coliform bacteria were found in samples irradiated at 1 kGy during refrigerated storage. Sensory evaluation indicated that the rancid flavor of samples irradiated at 4 kGy was significantly higher, but aroma and taste scores were lower than those of the control at Day 3 of storage. Irradiation of dry fermented sausages at 2 kGy was the best conditions to prolong the shelf-life and decrease the rancid flavor without significant quality deterioration.

  19. Stored energy of gamma-irradiated WIPP salt

    SciTech Connect

    Moss, M.

    1980-03-01

    Samples of WIPP salt exposed at 363/sup 0/K to gamma radiation from a /sup 60/Co source were annealed at constant rates of heating in a differential scanning calorimeter in order to release the energy stored. Radiation doses were 2.2, 5.4, 8.2, 11 and 13 x 10/sup 9/ rad, and temperature scans were conducted from room temperature to 800/sup 0/K. The specific stored energy-dose relationship deduced from 80 K/min scans could be only approximately established due to the extreme variability of the specific energy in samples of a given dose. This variability probably results from unequal amounts of impurities in the 10 to 25 mg samples required for the calorimeter. The energy-dose relationship is best described empirically by lnQ/sub 0/(cal/g) = (-40.6 +- 2.6) + (1.84 +- 0.12) lnD(rad). Temperature scans of 10, 20, 40, and 80 K/min were performed to determine the activation energy E of the annealing process. For the four more highly dosed samples, E = 31.1 +- 5.6 kcal/mole. Based upon criteria established elsewhere, there appears to be no danger of the stored energy being released quickly in a nuclear waste repository of bedded salt, nor could serious consequences result from such a release by some unforeseen mechanism.

  20. Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

    SciTech Connect

    Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

    1982-10-01

    Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with /sup 60/Co gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of /sup 60/Co radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.

  1. Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

    SciTech Connect

    Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

    1982-10-01

    Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with /sup 60/CO gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of /sup 60/CO radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. The authors found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.

  2. Degradation of trimethoprim by gamma irradiation in the presence of persulfate

    NASA Astrophysics Data System (ADS)

    Zhang, Zhonglei; Yang, Qi; Wang, Jianlong

    2016-10-01

    The degradation and mineralization of trimethoprim (TMP) by gamma irradiation was investigated in the presence of persulfate (PS). The TMP was degraded at initial concentration of 20 mg/L in aqueous solution with addition of 0, 0.5, 1, 1.5, 2 mM persulfate respectively. The effect of pH values (6.5, 7.5 and 8.5) on TMP degradation was also determined. The experimental results showed that the degradation and mineralization of TMP could be significantly enhanced by persulfate at acidic condition (pH=6.5). Several intermediate products generated during gamma irradiation process through hydroxylation, demethylation and cleavage were identified using liquid chromatography with tandem mass spectrometry (HPLC-MS). The degradation pathway of TMP was tentatively proposed based on the identification of intermediate products.

  3. {sup 17}O NMR investigation of oxidative degradation in polymers under gamma-irradiation

    SciTech Connect

    ALAM,TODD M.; CELINA,MATHIAS C.; ASSINK,ROGER A.; CLOUGH,ROGER LEE; GILLEN,KENNETH T.

    2000-03-08

    The {gamma}-irradiated-oxidation of pentacontane (C{sub 50}H{sub 102}) and the polymer polyisoprene was investigated as a function of oxidation level using {sup 17}O nuclear magnetic resonance (NMR) spectroscopy. It is demonstrated that by using {sup 17}O labeled O{sub 2} gas during the {gamma}-irradiation process, details about the oxidative degradation mechanisms can be directly obtained from the analysis of the {sup 17}O NMR spectra. Production of carboxylic acids is the primary oxygen-containing functionality during the oxidation of pentacontane, while ethers and alcohols are the dominant oxidation product observed for polyisoprene. The formation of ester species during the oxidation process is very minor for both materials, with water also being produced in significant amounts during the radiolytic oxidation of polyisoprene. The ability to focus on the oxidative component of the degradation process using {sup 17}O NMR spectroscopy demonstrates the selectivity of this technique over more conventional approaches.

  4. Inactivation by gamma irradiation of animal viruses in simulated laboratory effluent

    SciTech Connect

    Thomas, F.C.; Ouwerkerk, T.; McKercher, P.

    1982-05-01

    Several animal viruses were treated with gamma radiation from a /sup 60/Co source under conditions which might be found in effluent from an animal disease laboratory. Swine vesicular disease virus, vesicular stomatitis virus, and blue-tongue virus were irradiated in tissues from experimentally infected animals. Pseudorabies virus, fowl plague virus, swine vesicular disease virus, and vesicular stomatitis virus were irradiated in liquid animal feces. All were tested in animals and in vitro. The D/sub 10/ values, that is, the doses required to reduce infectivity by 1 log/sub 10/, were not apparently different from those expected from predictions based on other data and theoretical considerations. The existence of the viruses in pieces of tissues or in liquid feces made no differences in the efficacy of the gamma radiation for inactivating them. Under the ''worst case'' conditions (most protective for virus) simulated in this study, no infectious agents would survive 4.0 Mrads.

  5. Gamma-irradiation of malic acid in aqueous solutions. [prebiotic significance

    NASA Technical Reports Server (NTRS)

    Negron-Mendoza, A.; Graff, R. L.; Ponnamperuma, C.

    1980-01-01

    The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  6. One-step synthesis of graphene-Pt nanocomposites by gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Tokai, Akihiro; Okitsu, Kenji; Hori, Fuminobu; Mizukoshi, Yoshiteru; Iwase, Akihiro

    2016-06-01

    We developed a one-step gamma-ray irradiation method to synthesize nanocomposites composed of graphene and Pt nanoparticles from aqueous solution containing graphene and Pt(IV) complex ions in the presence of 2-propanol (IPA) or sodium dodecyl sulfate (SDS). It was confirmed that gamma-ray irradiation provided carbonyl groups on graphene and Pt nanoparticles formed from the radiolytic reduction of Pt(IV) complex ions were deposited onto the carbonyl modified graphene. In the presence of IPA, small Pt nanoparticles were deposited on graphene, but large Pt nanoparticles were deposited in the presence of SDS: the size of Pt nanoparticles formed was larger in the presence of SDS than IPA. Based on the results, formation and deposition mechanisms of Pt nanoparticles were proposed.

  7. Kinetics of hardness evolution during annealing of gamma-irradiated polycarbonate

    SciTech Connect

    Yeh, S. H.; Chen, P. Y.; Lee, Sanboh; Harmon, Julie

    2012-12-01

    This study focuses on the evolution in microhardness values that accompany isothermal annealing in gamma-irradiated polycarbonate (PC). Hardness increases with increasing annealing time, temperature, and gamma radiation dose. A model composed of a mixture of first and zero order structure relaxation is proposed to interpret the hardness data. The rate constant data fit the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The extent of structural relaxation that controls the hardness in post-annealed PC increases with increasing annealing temperature and dose. The model demonstrates that hardness evolution in PC is an endothermic process. By contrast, when the model is applied to irradiated poly(methyl methacrylate) and hydroxyethyl methacrylate copolymer, hardness evolution is an exothermic process.

  8. Dystrophic Changes in Extraocular Muscles after Gamma Irradiation in mdx:utrophin+/− Mice

    PubMed Central

    McDonald, Abby A.; Kunz, Matthew D.; McLoon, Linda K.

    2014-01-01

    Extraocular muscles (EOM) have a strikingly different disease profile than limb skeletal muscles. It has long been known that they are spared in Duchenne (DMD) and other forms of muscular dystrophy. Despite many studies, the cause for this sparing is not understood. We have proposed that differences in myogenic precursor cell properties in EOM maintain normal morphology over the lifetime of individuals with DMD due to either greater proliferative potential or greater resistance to injury. This hypothesis was tested by exposing wild type and mdx:utrophin+/− (het) mouse EOM and limb skeletal muscles to 18 Gy gamma irradiation, a dose known to inhibit satellite cell proliferation in limb muscles. As expected, over time het limb skeletal muscles displayed reduced central nucleation mirrored by a reduction in Pax7-positive cells, demonstrating a significant loss in regenerative potential. In contrast, in the first month post-irradiation in the het EOM, myofiber cross-sectional areas first decreased, then increased, but ultimately returned to normal compared to non-irradiated het EOM. Central nucleation significantly increased in the first post-irradiation month, resembling the dystrophic limb phenotype. This correlated with decreased EECD34 stem cells and a concomitant increase and subsequent return to normalcy of both Pax7 and Pitx2-positive cell density. By two months, normal het EOM morphology returned. It appears that irradiation disrupts the normal method of EOM remodeling, which react paradoxically to produce increased numbers of myogenic precursor cells. This suggests that the EOM contain myogenic precursor cell types resistant to 18 Gy gamma irradiation, allowing return to normal morphology 2 months post-irradiation. This supports our hypothesis that ongoing proliferation of specialized regenerative populations in the het EOM actively maintains normal EOM morphology in DMD. Ongoing studies are working to define the differences in the myogenic precursor cells

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

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  10. The impact of hyper-gravity and gamma-irradiation on physiology of wheat seedlings.

    NASA Astrophysics Data System (ADS)

    Singh, Sandhya; Vidyasagar, Pandit

    2016-07-01

    Exposing plants to altered gravity and gamma radiation can provide us with a fundamental knowledge of plant behavior in such conditions, since the mechanisms involved in response of plants to these stresses is still unclear. The more we understand these mechanisms the more we can apply this information to take the journey of life beyond the boundaries of earth. Hence many experiments were performed on pre-imbibed wheat seeds (Lok-1 variety), wherein they were exposed to hyper-gravity stress (300g-1500g) and gamma-irradiation (Dose 20Gy-100Gy) separately. After exposure these seeds were grown in normal conditions and their growth, fluorescence parameters, and total proline content were observed on the 5th day of their growth. A gradual decline in overall growth and fluorescence parameters, with increase in hyper-gravity stress value (300g-1500g) or gamma-irradiation dose (20Gy-100Gy) was observed. Interestingly in the hyper-gravity studies a consistent increase in the total proline content was observed only till 1200g but the total proline content deteriorated thereafter for higher 'g' values. On the other hand gamma irradiation studies revealed that the total proline content continuously increased with increase in the gamma radiation dose (20Gy-100Gy). Later, pre-imbibed seeds were exposed to both stresses (combined as hyper-gravity (300g-1500g) + gamma-irradiation (40Gy)) and same parameters were studied revealing that there was comparatively greater decline in overall growth and fluorescence parameters of wheat seedlings. Also the total proline content gradually increased ( from 300g+40Gy-900g+40Gy) with 900g+40Gy stress value having highest value of total proline content but the total proline content decreased subsequently for higher stress values (1200g+40Gy, 1500g+40Gy). Results obtained in the current research showed that exposing pre-imbibed wheat seeds to hyper-gravity stress, gamma radiation or both combined together may affect the proline biosynthesis and

  11. Electron spin resonance of gamma-irradiated poly/ethylene 2,6-naphthalene dicarboxylate/.

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Pezdirtz, G. F.

    1971-01-01

    Study of the ESR spectra of this gamma-irradiated compound (PEN-2,6) aimed at determining the effect of replacing the phenylene ring with naphthalene rings in the polymer on the formation of radicals and at identifying the radical species. The two types of radicals trapped in the PEN-2,6 compound have been identified as -O-CH-CH2-O- (radical I) and a radical located on the naphthalene ring (radical II).

  12. Effect of gamma irradiation on bacteriophages used as viral indicators.

    PubMed

    Jebri, Sihem; Hmaied, Fatma; Jofre, Juan; MariemYahya; Mendez, Javier; Barkallah, Insaf; Hamdi, Moktar

    2013-07-01

    This study aimed to examine the susceptibility of indicator bacteriophages towards γ-radiation to evaluate their appropriateness as viral indicators for water quality control. The effects of γ-radiation on naturally occurring somatic coliphages, F-specific coliphages and Escherichia coli were examined in raw sewage and sewage sludge. As well, the effects of radiation on bacteriophages ΦX174 and MS2, and E. coli all grown in the laboratory and seeded in distilled water, autoclaved raw sewage and a 1% peptone solution were evaluated. The inactivation of E. coli was fairly similar in all matrices. In contrast, inactivation of bacteriophages was significantly greater in distilled water than in the other matrices. These results showed the great influence of the matrix characteristics on virus inactivation. Somatic coliphages in raw sewage and sewage sludge and ΦX174 in autoclaved sewage were inactivated similarly and were far more resistant than F-specific coliphages, MS2 and E. coli. As well, F-specific RNA bacteriophages in raw sewage and sewage sludge and MS2 in autoclaved sewage were inactivated similarly and were more resistant than E. coli. In contrast, MS2 was more susceptible to γ-radiation than E. coli in distilled water. Our results showed that ΦX174 is a suitable indicator for estimating virus inactivation by γ-irradiation and corroborate the use of somatic coliphages to survey the viral quality of treated water and sludges.

  13. Virus inactivation studies using ion beams, electron and gamma irradiation

    NASA Astrophysics Data System (ADS)

    Smolko, Eduardo E.; Lombardo, Jorge H.

    2005-07-01

    Known methods of virus inactivation are based on the chemical action of some substances such as acetylethylenimine, betapropiolactone, glycidalaldehyde, formaldehyde, etc. In such a process, the viral suspension should be kept at room or higher temperatures for 24-48 h. Under these conditions, physical and chemical agents act to degrade the virus antigenic proteins. On the contrary with ionizing radiations at low temperatures, the treatment does not cause such degradation allowing the study of different viral functions. In this work, particle (α, d and ß) and γ irradiations were used for partial and total inactivation of Foot and Mouth Disease Virus (FMDV), Rauscher Leukemia Virus (RLV) and Herpes Simplex Virus (HSV). Obtention of the D37 dose from survival curves and the application of the target theory, permitted the determination of molecular weight of the nucleic acid genomes, EBR values and useful information for vaccine preparation. For RLV virus, a two target model of the RNA genome was deduced in accordance with biological information while from data from the literature and our own work on the structure of the scrapie prion, considering the molecular weight obtained by application of the theory, a new model for prion replication is presented, based on a trimer molecule.

  14. Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

    SciTech Connect

    Constanzo, Julie; Paquette, Benoit; Charest, Gabriel; Masson-Côté, Laurence; Guillot, Mathieu

    2015-05-15

    Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brain were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.

  15. Thermal, tensile and rheological properties of high density polyethylene (HDPE) processed and irradiated by gamma-ray in different atmospheres

    SciTech Connect

    Ferreto, H. F. R. E-mail: ana-feitoza@yahoo.com.br; Oliveira, A. C. F. E-mail: ana-feitoza@yahoo.com.br; Parra, D. F. E-mail: ablugao@ipen.br; Lugão, A. B. E-mail: ablugao@ipen.br; Gaia, R.

    2014-05-15

    The aim of this paper is to investigate structural changes of high density polyethylene (HDPE) modified by ionizing radiation (gamma rays) in different atmospheres. The gamma radiation process for modification of commercial polymers is a widely applied technique to promote new physical-chemical and mechanical properties. Gamma irradiation originates free radicals which can induce chain scission or recombination, providing its annihilation, branching or crosslinking. This polymer was irradiated with gamma source of {sup 60}Co at doses of 5, 10, 20, 50 or 100 kGy at a dose rate of 5 kGy/h. The changes in molecular structure of HDPE, after gamma irradiations were evaluated using thermogravimetric analysis (TGA) and tensile machine and oscillatory rheology. The results showed the variations of the properties depending on the dose at each atmosphere.

  16. Thermal behavior of gamma-irradiated low-density polyethylene/paraffin wax blend

    NASA Astrophysics Data System (ADS)

    Abdou, Saleh M.; Elnahas, H. H.; El-Zahed, H.; Abdeldaym, A.

    2016-05-01

    The thermal properties of low-density polyethylene (LDPE)/paraffin wax blends were studied using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and melt flow index (MFI). Blends of LDPE/wax in ratios of 100/0, 98/2, 96/4, 94/6, 92/8, 90/10 and 85/15 (w/w) were prepared by melt-mixing at the temperature of 150°C. It was found that increasing the wax content more than 15% leads to phase separation. DSC results showed that for all blends both the melting temperature (Tm) and the melting enthalpy (ΔHm) decrease linearly with an increase in wax content. TGA analysis showed that the thermal stability of all blends decreases linearly with increasing wax content. No clear correlation was observed between the melting point and thermal stability. Horowitz and Metzger method was used to determine the thermal activation energy (Ea). MFI increased exponentially by increasing the wax content. The effect of gamma irradiation on the thermal behavior of the blends was also investigated at different gamma irradiation doses. Significant correlations were found between the thermal parameters (Tm, ΔHm, T5%, Ea and MFI) and the amount of wax content and gamma irradiation.

  17. EPR study of radicals produced by gamma-irradiation in marine mollusc (Venus sp.) fossils

    NASA Astrophysics Data System (ADS)

    Koseoglu, R.; Koksal, F.; Ciftci, E.

    2004-08-01

    In this study, gamma-irradiated marine mollusc (Venus sp.) fossils were investigated by electron paramagnetic resonance (EPR) at ambient temperature. Powder X-ray diffraction technique indicates that the Venus sp. fossils were made mainly of CaCO3. Before gamma-irradiation, the EPR lines of the powder of fossil samples showed the existence of Mn2+ (I = 5/2, 100% natural abundance) ions with g(av) = 2.0055 and A(av) = 9.4 mT gamma-Irradiation-induced additional defects in Venus sp. fossil were attributed to axial CO3- (gperpendicular to = 2.0171, g// = 2.0048), orthorhombic CO2- (g(x) = 2.0030, g(z) = 2.0018, g(y) = 1.9973, g(av) = 2.0007), freely rotating CO2- (g(iso) = 2.0007), isotropic SO2- (g = 2.0057), axial SO3- (g perpendicular to = 2.0036, g// = 2.0024) and isotropic SO3- (g = 2.0032) free radicals. The g-values of these free radicals were compared with the literature data belonging to similar defects.

  18. Tube shunt coverage with gamma-irradiated cornea allograft (VisionGraft)

    PubMed Central

    Ekici, Feyzahan; Moster, Marlene R; Cvintal, Victor; Hu, Wanda D; Waisbourd, Michael

    2015-01-01

    Purpose To investigate the clinical outcomes of tube shunt coverage using sterile gamma-irradiated cornea allograft. Patients and methods The Wills Eye Hospital Glaucoma Research Center retrospectively reviewed the medical records of 165 patients who underwent glaucoma tube shunt procedures using sterile gamma-irradiated cornea allograft (VisionGraft) between December 2012 and November 2013. Demographic characteristics, type of tube shunt, and position were noted. Complications were recorded at 1 day; 1 week; 1, 3, 6, and 12 months; and on the final postoperative visit. Results One hundred and sixty-nine eyes of 165 patients were included. The mean follow-up time was 4.8±3.5 (ranging from 1 to 16) months. There was no evidence of immunological reaction, infection, or exposure in 166 eyes (98.2%). Three eyes (1.8%) experienced graft or tube exposure within the first 3 postoperative months. Two of the cases had underlying diseases: bullous pemphigoid and chronic allergic conjunctivitis. Conclusion Coverage of tube shunts using gamma-irradiated cornea allograft had a low exposure rate and was well tolerated. The graft can be stored long term at room temperature and has an excellent postoperative cosmetic appearance. PMID:25995612

  19. Electron paramagnetic resonance of natural and gamma-irradiated alunite and kaolin mineral powders

    NASA Astrophysics Data System (ADS)

    Koksal, F.; Koseoglu, R.; Saka, I.; Basaran, E.; Sener, F.

    2004-06-01

    Natural alunite and kaolin minerals obtained from West Anatolia were investigated by electron paramagnetic resonance (EPR) in natural and gamma-irradiated states at room temperature and at 113 K. The paramagnetic centres at ambient temperature in natural alunite were attributed to the (C) over dot H 2OH, (C) over dot O-3(-), (S) over dot O-2(-), (C) over dot O-2(-) and [AlO4 ](0) radicals. In natural kaolin, the paramagnetic centres were attributed to the (C) over dot O-3(-), (S) over dot O-2(-) (C) over dot O-2(-) and [AlO4](0) radicals. The gamma-irradiation does not produce any detectable effects on these radicals. At 113 K, the lines for (C) over dot H2OH could not be observed well, probably due to the anisotropic behaviour of the hyperfine interaction of the methylene protons, but the lines for [AlO4](0) centres were found to be perfectly observable at above 20 mW microwave power in both alunite and kaolin powders before and after gamma-irradiation. The EPR parameters of the observed paramagnetic centres were reported.

  20. Characterization of modified PVDF membrane by gamma irradiation for non-potable water reuse.

    PubMed

    Lim, Seung Joo; Kim, Tak-Hyun; Shin, In Hwan

    2015-01-01

    Poly(vinylidene fluorine) (PVDF) membranes were grafted by gamma-ray irradiation and were sulfonated by sodium sulfite to modify the surface of the membranes. The characteristics of the modified PVDF membranes were evaluated by the data of Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscope (FE-SEM), the contact angle of the membrane surface and the water permeability. From the results of FT-IR, XPS and FE-SEM, it was shown that the modified membranes were successfully grafted by gamma-ray irradiation and were sulfonated. The content of oxygen and sulfur increased with the monomer concentration, while the content of fluorine sharply decreased. The pore size of the modified membranes decreased after gamma-ray irradiation. The contact angle and the water permeability showed that the hydrophilicity of the modified membranes played a role in determining the membrane performance. The feasibility study of the modified PVDF membranes for using non-potable water reuse were carried out using a laboratory-scale microfiltration system. Grey wastewater was used as the influent in the filtration unit, and permeate quality satisfied non-potable water reuse guidelines in the Republic of Korea. PMID:25812106

  1. Inactivation of RNA Viruses by Gamma Irradiation: A Study on Mitigating Factors

    PubMed Central

    Hume, Adam J.; Ames, Joshua; Rennick, Linda J.; Duprex, W. Paul; Marzi, Andrea; Tonkiss, John; Mühlberger, Elke

    2016-01-01

    Effective inactivation of biosafety level 4 (BSL-4) pathogens is vital in order to study these agents safely. Gamma irradiation is a commonly used method for the inactivation of BSL-4 viruses, which among other advantages, facilitates the study of inactivated yet morphologically intact virions. The reported values for susceptibility of viruses to inactivation by gamma irradiation are sometimes inconsistent, likely due to differences in experimental protocols. We analyzed the effects of common sample attributes on the inactivation of a recombinant vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein and green fluorescent protein. Using this surrogate virus, we found that sample volume and protein content of the sample modulated viral inactivation by gamma irradiation but that air volume within the sample container and the addition of external disinfectant surrounding the sample did not. These data identify several factors which alter viral susceptibility to inactivation and highlight the usefulness of lower biosafety level surrogate viruses for such studies. Our results underscore the need to validate inactivation protocols of BSL-4 pathogens using “worst-case scenario” procedures to ensure complete sample inactivation. PMID:27455307

  2. Inactivation of Alicyclobacillus acidoterrestris spores in apple and orange juice concentrates by gamma irradiation.

    PubMed

    Lee, Su-Yeon; Park, Sang-Hyun; Kang, Dong-Hyun

    2014-02-01

    The objective of this study was to evaluate the effect of different concentrations of reconstituted apple and orange juice on reduction of Alicyclobacillus acidoterrestris spores by gamma irradiation. Spores of A. acidoterrestris were inoculated into three concentrations of apple (18, 36, and 72 °Brix) and orange (11, 33, and 66 °Brix) juice and subjected to five radiation doses (1, 3, 5, 7, and 10 kGy). No significant reductions (P > 0.05) in spores were observed after the 1-kGy treatment for all apple and orange concentrations. Spores in 18, 36, and 72 °Brix apple juice concentrates subjected to 10 kGy were reduced to 4.34, 3.9, and 3.84 log CFU/ml, respectively. Similar results were observed for orange juice. When 10 kGy was applied to 11 °Brix orange juice, populations of spores were reduced by 5 log CFU/ml. The reduction of spores in 33 and 66 °Brix orange juice concentrates exposed to 10-kGy gamma irradiation was 4.54 and 3.85 log CFU/ml, respectively. Juice concentration did not affect (P > 0.05) the number of surviving A. acidoterrestris spores from the same kGy treatment. Gamma irradiation treatment did not change the pH or water activity of the juice (P > 0.05).

  3. Inactivation of RNA Viruses by Gamma Irradiation: A Study on Mitigating Factors.

    PubMed

    Hume, Adam J; Ames, Joshua; Rennick, Linda J; Duprex, W Paul; Marzi, Andrea; Tonkiss, John; Mühlberger, Elke

    2016-01-01

    Effective inactivation of biosafety level 4 (BSL-4) pathogens is vital in order to study these agents safely. Gamma irradiation is a commonly used method for the inactivation of BSL-4 viruses, which among other advantages, facilitates the study of inactivated yet morphologically intact virions. The reported values for susceptibility of viruses to inactivation by gamma irradiation are sometimes inconsistent, likely due to differences in experimental protocols. We analyzed the effects of common sample attributes on the inactivation of a recombinant vesicular stomatitis virus expressing the Zaire ebolavirus glycoprotein and green fluorescent protein. Using this surrogate virus, we found that sample volume and protein content of the sample modulated viral inactivation by gamma irradiation but that air volume within the sample container and the addition of external disinfectant surrounding the sample did not. These data identify several factors which alter viral susceptibility to inactivation and highlight the usefulness of lower biosafety level surrogate viruses for such studies. Our results underscore the need to validate inactivation protocols of BSL-4 pathogens using "worst-case scenario" procedures to ensure complete sample inactivation. PMID:27455307

  4. Radiation resistance of a gamma-ray irradiated nonlinear optic chromophore

    NASA Astrophysics Data System (ADS)

    Zhang, Cheng; Taylor, Edward W.

    2009-11-01

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

  5. Gamma-irradiation stability of saturated and unsaturated aliphatic polyanhydrides--ricinoleic acid based polymers.

    PubMed

    Teomim, D; Mäder, K; Bentolila, A; Magora, A; Domb, A J

    2001-01-01

    The effect of terminal sterilization by gamma-irradiation on several ricinoleic acid based polyanhydrides was investigated. The following polymers were used: poly(ricinoleic acid maleate) [P(RAM)], poly(ricinoleic acid succinate) [P(RAS)], poly(hydroxy stearic acid succinate) [P(HSAS)], poly(hydroxy stearic acid maleate) [P(HSAM)], and their copolymers with sebacic acid. The polymers were irradiated with an absorbed dose of 2.5 or 10 Mrad by means of a 60Co source under dry ice or at room temperature. No differences were found between samples irradiated under dry ice and at room temperature. Polymers prepared from monomers containing maleate residues, which contain double bonds adjusted to the anhydride linkage along the polymer chain, decreased in molecular weight, became insoluble, and showed fast hydrolytic degradation. For example, p(RAM), p(HSAM), and their copolymers with sebacic acid decreased in Mw from about 10,000 to about 2000, and from about 30,000 to about 5000, respectively, while polymers based on RAS and HSAS remained stable. This phenomenon was explained by an anhydride interchange-self-depolymerization process of the unsaturated anhydride bonds induced by gamma-irradiation. This explanation was supported by the depolymerization of another class of polymers having an anhydride bond between two double bonds, fumaric acid anhydride polymers. The anhydride bond that lies between two double bonds was found to be more sensitive to gamma-irradiation. This anhydride bond may be cleaved to form two radicals that further react with aliphatic anhydride bonds along the polymer chain to form inter- and/or intracyclization products. PMID:11710004

  6. Gamma irradiation and red cell haemolysis: a study at the Universiti Kebangsaan Malaysia Medical Centre.

    PubMed

    Yousuf, Rabeya; Mobin, Mohd Herman; Leong, Chooi Fun

    2015-08-01

    Gamma-irradiation of blood components is regarded a safe procedure used for prevention of transfusion associated graft-versus-host disease. However, reports showed that irradiation can cause erythrocyte haemolysis and damage to the RBC membrane. In University Kebangsaan Malaysia Medical Centre (UKMMC), a number of suspected transfusion reactions (TR) featured unusual isolated episodes of red-coloured-urine or haemoglobinuria among paediatric patients without clinical features of acute haemolytic TR. Haemolysis of irradiated red cells was suspected as a cause. This study was conducted to evaluate haemolytic changes of RBC components following irradiation. A prospective, pre- and post- irradiation comparative study was conducted on 36 paired RBC-components in the blood-bank, UKMMC in the year 2013. Samples were tested for plasma-Hb, percent-haemolysis, plasma-potassium (K⁺) and lactate dehydrogenase (LDH) level. Post-irradiation mean plasma-Hb and percent-haemolysis were significantly higher than pre-irradiation values at 0.09 ±0.06g/dl VS 0.10 ± 0.06g/dl and 0.19 ± 0.13% VS 0.22 ± .13% respectively, while plasma-K⁺ and LDH values did not show significant difference. However, the mean percent-haemolysis level was still within recommended acceptable levels for clinical use, supporting that irradiated RBC units were safe and of acceptable quality for transfusion. There was no conclusive reason for isolated haemoglobinuria following transfusion of irradiated red-cell products. Further research is suggested to investigate the other possible causes.

  7. Effect of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3).

    PubMed

    Pandya, G A; Prakash, L; Devasia, P; Modi, V V

    1988-01-01

    The effects of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3) in pot cultures have been studied. Compared to plants grown only in soil, shoot length, root length, fresh weight, dry weight, total proteins, total soluble sugars, starch and chlorophyll content of plants grown in soil supplemented with unirradiated or gamma-irradiated sludge were found to be significantly increased. Irradiation of sludge significantly stimulated the linear growth of shoot and root systems as well as fresh and dry weights of plants, compared to those grown in soil containing unirradiated sludge. There was also an improvement in the grain yield (weight of seed) when plants were grown in soil supplemented with irradiated sludge. The results obtained suggest that the gamma-irradiated sewage sludge can be beneficially recycled for agricultural uses.

  8. Effects of gamma irradiation on chemical composition and antioxidant potential of processed samples of the wild mushroom Macrolepiota procera.

    PubMed

    Fernandes, Ângela; Barreira, João C M; Antonio, Amilcar L; Oliveira, M Beatriz P P; Martins, Anabela; Ferreira, Isabel C F R

    2014-04-15

    It was previously demonstrated that gamma irradiation was the processing technology with the highest capacity to maintain the chemical profile of fresh Macrolepiota procera wild mushroom, when compared to freeze-dried or oven-dried samples. Herein, it was aimed to evaluate gamma irradiation effects on processed samples. Chemical composition and antioxidant potential of irradiated (0.5 and 1 kGy) fresh, frozen and dried samples were determined by chromatographic techniques and in vitro assays, respectively. M. procera irradiation attenuated the effects caused by oven-drying or freezing; combining freeze treatment with 0.5 kGy dose preserved total tocopherols. Rather than a conservation methodology, gamma irradiation might act as a useful adjuvant to other conservation techniques (e.g., freezing or oven-drying).

  9. Effect of gamma irradiation and its convergent treatment for control of postharvest Botrytis cinerea of cut roses

    NASA Astrophysics Data System (ADS)

    Chu, Eun-Hee; Shin, Eun-Jung; Park, Hae-Jun; Jeong, Rae-Dong

    2015-10-01

    Postharvest diseases cause considerable losses to harvested crops. Among them, gray mold (Botrytis cinerea) is a major problem of exporting to cut rose flowers into Korea. Irradiation treatment is an alternative to phytosanitary purposes and a useful nonchemical approach to the control of postharvest diseases. Gamma irradiation was evaluated for its in vitro and in vivo antifungal activity against B. cinerea on cut rose varieties, 'Shooting Star' and 'Babe'. The irradiating dose required to reduce the population by 90%, D10, was 0.99 kGy. Gamma irradiation showed complete inhibition of spore germination and mycelial growth of B. cinerea, especially 4.0 kGy in vitro. Antifungal activity of gamma irradiation on rose B. cinerea is a dose-dependent manner. A significant phytotoxicity such as bent neck in cut rose quality was shown from gamma irradiation at over 0.4 kGy (p<0.05) in both varieties. Although there is no significant difference in both varieties for fresh weight, in the case of flower rate, 'Babe' shows more sensitivity than 'Shooting Star'. In vivo assays demonstrated that established doses in in vitro, over 4 kGy, could completely inactive fungal pathogens, but such high doses can cause severe flowers damage. Thus, to eliminate negative impact on their quality, gamma irradiation was evaluated at lower doses in combination with an eco-friendly chemical, sodium dichloroisocyanurate (NaDCC) to examine the inhibition of B. cinerea. Intriguingly, only the combined treatment with 0.2 kGy of gamma irradiation and 70 ppm of NaDCC exhibited significant synergistic antifungal activity against blue mold decay in both varieties. Together, these results suggest that a synergistic effect of the combined treatment with gamma irradiation and NaDCC can be efficiently used to control the postharvest diseases in cut rose flowers, and will provide a promising technology for horticulture products for exportation.

  10. Application of gamma irradiation for inactivation of three pathogenic bacteria inoculated into meatballs

    NASA Astrophysics Data System (ADS)

    Gumus, Tuncay; Şukru Demirci, A.; Murat Velioglu, H.; Velioglu, Serap D.; Yilmaz, Ismail; Sagdic, Osman

    2008-09-01

    In this research, the effect of gamma irradiation on the inactivation of Escherichia coli O157:H7 (ATCC 33150), Staphylococcus aureus (ATCC 2392) and Salmonella typhimurium (NRRL 4463) inoculated into Tekirdag meatballs was investigated. The meatball samples were inoculated with pathogens and irradiated at the absorbed doses of 1, 2.2, 3.2, 4.5 and 5.2 kGy. E. coli O157:H7 count in 1 kGy irradiated meatballs stored in the refrigerator for 7 days was detected to be 4 log cfu/g lower than the count in nonirradiated samples ( p<0.05). S. aureus counts were decreased to 4 log cfu/g after being exposed to irradiation at a dose of 1 kGy. Although it was ineffective on elimination of S. typhimurium, irradiation at a dose of 3.2 kGy reduced E. coli O157:H7 and S. aureus counts under detectable values in the meatballs. However, none of the test organisms were detected in the samples after irradiation with 4.5 kGy doses.

  11. Effect of gamma-ray irradiation at low doses on the performance of PES ultrafiltration membrane

    NASA Astrophysics Data System (ADS)

    Zhang, Xue; Niu, Lixia; Li, Fuzhi; Yu, Suping; Zhao, Xuan; Hu, Hongying

    2016-10-01

    The influence of gamma irradiation on the performance of polyether sulfone (PES) ultrafiltration (UF) membrane was investigated at low absorbed doses (0-75 kGy) using a cobalt source. The performance of the UF membranes was tested using low level radioactive wastewater (LLRW) containing three types of surfactants (anionic, cationic and nonionic surfactants). The physical and chemical properties of membrane surface were analyzed, and relationships between these properties and separation performance and fouling characteristics were determined. At 10-75 kGy irradiation, there were no significant changes observed in the membrane surface roughness or polymer functional groups, however the contact angle decreased sharply from 92° to ca. 70° at irradiation levels as low as 10 kGy. When membranes were exposed to the surfactant-containing LLRW, the flux decreased more sharply for higher dosed irradiated membranes, while flux in virgin membranes increased during the filtration processes. The study highlights that fouling properties of membrane may be changed due to the changes of surface hydrophilicity at low dose irradiation, while other surface properties and retentions remain stable. Therefore, a membrane fouling test with real or simulated wastewater is recommended to fully evaluate the membrane irradiation resistance.

  12. EPR study of gamma-irradiated 2-Bromo-4'-methoxyacetophenone single crystals

    NASA Astrophysics Data System (ADS)

    Ugur Tasdemir, Halil; Türkkan, Ercan; Sayin, Ulku; Ozmen, Ayhan

    2016-03-01

    The gamma-irradiated single crystals of 2-Bromo-4‧-methoxyaceto-phenone (2B4MA) were investigated using electron paramagnetic resonance (EPR) technique. Density-functional theory calculations were employed to investigate and identify the radicals that have been assumed to be formed upon irradiation of 2B4MA single crystals. The EPR spectra of 2B4MA were recorded at different orientations in the magnetic field at room temperature. Taking into account the chemical structure and experimental spectra of irradiated single crystal of 2B4MA, it was assumed that at least two different radicals were produced in the sample. Following this assumption, six possible radicals were modeled and EPR parameters were calculated by using the DFT, B3LYP/6-311+G(d), for the modeled radicals individually. The calculated hyperfine coupling constants and g-tensors were used as initial values for simulation studies. The three crystallographic axes on the simulated spectra were well matched with experimental spectra for the two modeled radicals. Thus, we identified the R1 type radical and R4 type radical as paramagnetic species produced in gamma-irradiated 2B4MA.

  13. Effect of gamma irradiation on cell lysis and polyhydroxyalkanoate produced by Bacillus flexus

    NASA Astrophysics Data System (ADS)

    Divyashree, M. S.; Shamala, T. R.

    2009-02-01

    Bacillus flexus cultivated on sucrose and sucrose with plant oil such as castor oil produced polyhydroxybutyrate (PHB), a homopolymer of polyhydroxyalkanoate (PHA) and PHA copolymer (containing hydroxybutyrate and hexanoate), respectively. Gamma irradiation of these cells (5-40 kGy) resulted in cell damage and aided in the isolation of 45% and 54% PHA on biomass weight, correspondingly. Molecular weight of PHB increased from 1.5×10 5 to 1.9×10 5 after irradiation (10 kGy), with marginal increase of tensile strength from 18 to 20 MPa. At the same irradiation dosage, PHA copolymer showed higher molecular weight increase from 1.7×10 5 to 2.3×10 5 and tensile strength from 20 to 35 MPa. GC, GC-MS, FTIR and 1H NMR were used for the characterization of PHA. Gamma irradiation seems to be a novel technique, to induce cross-linking and molecular weight increase of PHA copolymer and aid in easy extractability of intracellular PHA, simultaneously.

  14. Aliphatic glucosinolate synthesis and gene expression changes in gamma-irradiated cabbage.

    PubMed

    Banerjee, Aparajita; Rai, Archana N; Penna, Suprasanna; Variyar, Prasad S

    2016-10-15

    Glucosinolates, found principally in the plant order Brassicales, are modulated by different post-harvest processing operations. Among these, ionizing radiation, a non-thermal process, has gained considerable interest for ensuring food security and safety. In gamma-irradiated cabbage, enhanced sinigrin, a major glucosinolate, has been reported. However, the molecular basis of such a radiation induced effect is not known. Herein, the effect of radiation processing on the expression of glucosinolate biosynthetic genes was investigated. RT-PCR based expression analysis of seven glucosinolate biosynthetic pathway genes (MYB28, CYP79F1, CYP83A1, SUR1, UGT74B1, SOT18 and TGG1) showed that CYP83A1, MYB28, UGT74B1, CYP79F1 and SUR1 were up-regulated in irradiated cabbage. The content of jasmonates, signalling molecules involved in glucosinolate induction was, however, unaffected in irradiated cabbage suggesting their non-involvement in glucosinolate induction during radiation processing. This is the first report on the effect of gamma irradiation on the expression of glucosinolate biosynthetic genes in vegetables.

  15. Neural network modelling of dose distribution and dose uniformity in the Tunisian Gamma Irradiator.

    PubMed

    Manai, K; Trabelsi, A

    2013-11-01

    In this paper an approach to model dose distributions, isodose curves and dose uniformity in the Tunisian Gamma Irradiation Facility using artificial neural networks (ANNs) are described. For this purpose, measurements were carried out at different points in the irradiation cell using polymethyl methacrylate dosemeters. The calculated and experimental results are compared and good agreement is observed showing that ANNs can be used as an efficient tool for modelling dose distribution in the gamma irradiation facility. Monte Carlo (MC) photon-transport simulation techniques have been used to evaluate the spatial dose distribution for extensive benchmarking. ANN approach appears to be a significant advance over the time-consuming MC or the less accurate regression methods for dose mapping. As a second application, a detailed dose mapping using two different product densities was carried out. The minimum and maximum dose locations and dose uniformity as a function of the irradiated volume for each product density were determined. Good agreement between ANN modelling and experimental results was achieved.

  16. Potential of recycling gamma-irradiated sewage sludge for use as a fertilizer: a study on chickpea (Cicer arietinum).

    PubMed

    Pandya, G A; Sachidanand, S; Modi, V V

    1989-01-01

    The effects of gamma-irradiated sludge on the growth and yield of chickpea (Cicer arietinum) in pot cultures have been studied. Compared to plants grown only in soil, root length, fresh weight and dry weight of plants grown in soil supplemented with unirradiated sludge were found to be significantly reduced. This inhibition in growth was found to be nullified when plants were grown in soil supplemented with gamma-irradiated sludge, suggesting that gamma radiation induced inactivation of toxic substance(s) in sludge. The protein content of plants grown in soil supplemented with irradiated sludge was also found to be significantly increased compared to those grown with unirradiated or no sludge, after 45 days. There was no significant effect of gamma irradiated sludge on shoot length, total soluble sugars, starch content and yield of chickpea plants. The results obtained suggest that the sludge tested, and obtained from the digester of a conventional domestic sewage treatment plant, is inhibitory to several growth parameters. Gamma irradiation of sewage resulted in removal of this inhibition. This suggests a possibility of beneficial and safe recycling of gamma-irradiated sludge for agricultural uses.

  17. Influence of gamma irradiation on structural, thermal and antibacterial properties of HPMC/ZnO nanocomposites

    NASA Astrophysics Data System (ADS)

    Rao, B. Lakshmeesha; Madhukumar, R.; Latha, S.; Shetty, G. Rajesha; Shivananda, C. S.; Chandra, K. Sharath; Sangappa, Y.

    2016-05-01

    This work was carried out to evaluate the effect of gamma irradiation on the structural, thermal and antibacterial properties of HPMC/ZnO nanocomposite films exposed to Cobalt-60 (Average energy: 1.25MeV). The X-ray diffraction study revealed that the crystallite size (L in Å) decreased as irradiation dose increased. The crystallinity (Xc) of the nanocomposites initially increased and at higher doses it was decreased. The thermal stability of the nanocomposites increased up to 50 kGy and after that decreased as the irradiation dose increased. But, HPMC/ZnO nanocomposite films, showed a promising range of antimicrobial activity against tested micro-organisms making nanocomposites suitable for food packing and other biomedical applications.

  18. Electron trapping in rad-hard RCA IC's irradiated with electrons and gamma rays

    NASA Technical Reports Server (NTRS)

    Danchenko, V.; Brashears, S. S.; Fang, P. H.

    1984-01-01

    Enhanced electron trapping has been observed in n-channels of rad-hard CMOS devices due to electron and gamma-ray irradiation. Room-temperature annealing results in a positive shift in the threshold potential far beyond its initial value. The slope of the annealing curve immediately after irradiation was found to depend strongly on the gate bias applied during irradiation. Some dependence was also observed on the electron dose rate. No clear dependence on energy and shielding over a delidded device was observed. The threshold shift is probably due to electron trapping at the radiation-induced interface states and tunneling of electrons through the oxide-silicon energy barrier to fill the radiation-induced electron traps. A mathematical analysis, based on two parallel annealing kinetics, hole annealing and electron trapping, is applied to the data for various electron dose rates.

  19. Studies of dielectric properties of mammalian tissues after gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Abd El-Salaam, S.; Sallam, S.; Talaat, M. S.

    1996-12-01

    In vitro dielectric measurements (relative permeability and conductivity) of excised liver, kidney, cardiac muscle, spleen and eye of rabbits, were carried out at frequencies of 1-250 kHz and at room temperature. These were done before, immediately and 7 days after gamma irradiation at doses 1-5 Gy. The obtained results indicated significant increase in both relative permitivity and conductivity of tissues at higher doses immediately after irradiation. After 7 days, the changes showed some recovery, more obvious at lower doses. These changes in dielectric properties, after irradiation, may reflect the particular biological organization of each tissue and some mechanisms of radiation damage to these tissues particular to cell membrane, counter-ion polarization associated with intrinsic membrane charges and conductive transport in extracellular medium. This may help to elucidate the mechanisms of variation of dielectric properties of different tissues under the effect of radiation.

  20. Gamma-irradiation tests of IR optical fibres for ITER thermography--a case study

    SciTech Connect

    Reichle, R.; Pocheau, C.; Jouve, M.

    2008-03-12

    In the course of the development of a concept for a spectrally resolving infrared thermography diagnostic for the ITER divertor we have tested 3 types of infrared (IR) fibres in Co{sup 60} irradiation facilities under {gamma} irradiation. The fibres were ZrF{sub 4} (and HfF{sub 4}) fibres from different manufacturers, hollow fibres (silica capillaries with internal Ag/AgJ coating) and a sapphire fibre. For the IR range, only the latter fibre type encourages to go further for neutron tests in a reactor. If one restricted the interest onto the near infrared range, high purity core silica fibres could be used. This study might be seen as a typical example of the relation between diagnostic development for a nuclear environment and irradiation experiments.

  1. Radiation decomposition of trichlorofluoromethane in flow system under 60Co gamma-ray irradiation.

    PubMed

    Yamamoto, T; Ootsuka, N

    1982-12-01

    Irradiation experiments of CCl3F were carried out with 60Co gamma-rays using the irradiation facility of the flow system. In the system, CCl3F was irradiated at 5.7 kGg/h (5.7 X 10(5) rad/h) and -30 degrees C. The decomposition behavior of CCl3F and the influence of impurities in the circulating gas on the decomposition were examined. The result was compared with that of ampoule scale. The decomposition yield of CCl3F and the yields of radiolytic products (fluorocarbons) increased in proportion to the absorbed dose. The decomposition yield per Mrad of CCl3F was 0.0246 mol%/Mrad (G = 2.9). This value was equal to 1.8 times that of the ampoule scale. The marked influence of impurities (air, CH4, I2) was recognized for the yields of halogen ions. PMID:7170349

  2. Characterization and potential applications of gamma irradiated chitosan and its blends with poly(vinyl alcohol).

    PubMed

    Bano, Ijaz; Ghauri, Muhammad Afzal; Yasin, Tariq; Huang, Qingrong; Palaparthi, Annie D'Souza

    2014-04-01

    Naturally available chitosan (CHI), of high molecular weight, results in reduced efficiency of these polymers for antibacterial activity. In this regard, irradiation is a widely used method for achieving reduction in molecular weight of polymers, which may improve some of its characteristics. Chitosan was extracted from crab shells and degraded by gamma radiations. Effect of radiation dose on chitosan was analyzed by Fourier transform infrared (FTIR) spectroscopy. Furthermore, the irradiated chitosan was blended with poly(vinyl alcohol) (PVA) and crosslinked with tetraethylorthosilicate (TEOS) into membranes. The membranes were found to be smooth, transparent and macroporous in structure, exhibiting high tensile strength (TS: 27-47 MPa) and elongation at break (EB: 292.6-407.3%). The effect of molecular weight of chitosan and chitosan blends on antibacterial activity was determined. Irradiated low molecular weight chitosan and membranes showed strong antibacterial activity against Escherichia coli and Bacillus subtilis.

  3. Effect of gamma irradiation on dielectric properties of manganese zinc nanoferrites

    SciTech Connect

    Angadi, V. Jagadeesha Rudraswamy, B.; Melagiriyappa, E.; Somashekarappa, H. M.; Nagabhushana, H.

    2014-04-24

    Naocrystalline ferrites Mn{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.00, 0.25, 0.50, 0.75 and 1.00) were prepared by combustion method. The samples were characterized by XRD technique. The dielectric measurements were carried out in the frequency range 40 Hz to 100 MHz at room temperature. All the measurements were performed before and after gamma {sup 60}Co irradiation. The X-ray diffraction patterns revealed the formation of nanocrystalline and single-phase spinel structure. The lattice parameter decrease with zinc ion concentration and increased after the irradiation due to ferric ions of smaller radius converted to ferrous ions of larger radius. The dielectric behavior is attributed to the Maxwell-Wagner type interfacial polarization. The dielctric contant, dielectric loss and AC conductivity enhanced after the irradiation.

  4. dl-. cap alpha. -tocopheryl succinate enhances the effect of. gamma. -irradiation on neuroblastoma cells in culture

    SciTech Connect

    Sarri, A.; Prasad, K.N.

    1984-01-01

    The effect of dl-..cap alpha..-tocopheryl (vitamin E) succinate in modifying the radiation response of mouse neuroblastoma (NBP/sub 2/) and mouse fibroblast (L-cells) cells in culture was studied on the criterion of growth inhibition (due to cell death and inhibition of cell division). Results show that vitamin E succinate markedly enhanced the effect of /sub 60/CO-..gamma..-irradiation on NB cells, but it did not significantly modify the effect of irradiation on mouse fibroblasts. Sodium succinate plus ethanol (0.25% final concentration) did not modify the radiation response of NB cells or fibroblasts. Butylated hydroxyanisole, a lipid soluble antioxidant, also enhanced the effect of irradiation on NB cells, indicating that the effect of vitamin E in modifying the radiation response may be mediated, in part, by antioxidation mechanisms.

  5. Molecular weight changes induced in an anionic polydimethylsiloxane by gamma irradiation in vacuum

    NASA Astrophysics Data System (ADS)

    Satti, Angel J.; Andreucetti, Noemí A.; Ciolino, Andrés E.; Vitale, Cristian; Sarmoria, Claudia; Vallés, Enrique M.

    2010-11-01

    An anionic almost monodisperse linear polydimethylsiloxane (PDMS) was subjected to gamma irradiation under vacuum at room temperature. The molecular weight changes induced by the radiation process have been investigated using size exclusion chromatography (SEC) with refraction index (RI) and multi angle laser light scattering (MALLS) detectors, to obtain the number and weight average molecular weights of the irradiated samples. The analysis of the data indicates that crosslinking reactions predominated over scission reactions. The results obtained by an SEC-RI have confirmed the presence of small, but measurable amounts of scission. A previously developed mathematical model of the irradiation process that accounts for simultaneous scission and crosslinking and allows for both H- and Y-crosslinks, fitted well the measured molecular weight data. This prediction is in accordance with the experimental data obtained by 29Si-Nuclear Magnetic Resonance spectroscopy (NMR) and previously reported data for commercial linear PDMS ( Satti et al., 2008).

  6. Volatile compounds and odor traits of dry-cured ham (Prosciutto crudo) irradiated by electron beam and gamma ray

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prosciutto crudo were irradiated at 0, 3 and 6kGy by gamma ray (GR) and electron beam (EB), respectively. The odor scores and volatile compounds were examined after 7 days storage at 4'. Volatile compounds from samples without and with irradiation at 6kGy were analyzed by GC-MS. Fifty-nine compounds...

  7. Evaluation of some selected vaccines and other biological products irradiated by gamma rays, electron beams and X-rays

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

    Molecular sizing potency results are presented for irradiated samples of one lot of Haemophilus b conjugate vaccine, pneumococcal polysaccharide type 6B and typhoid vi polysaccharide vaccine. The samples were irradiated (25 kGy) by gamma rays, electron beams and X-rays. IgG and IgM antibody response in mice test results (ELISA) are given for the Hib conjugate vaccine irradiated at 0°C or frozen in liquid nitrogen.

  8. Effect of gamma irradiation and cooking on cowpea bean grains ( Vigna unguiculata L. Walp)

    NASA Astrophysics Data System (ADS)

    Lima, Keila dos Santos Cople; Souza, Luciana Boher e.; Godoy, Ronoel Luiz de Oliveira; França, Tanos Celmar Costa; Lima, Antônio Luís dos Santos

    2011-09-01

    Leguminous plants are important sources of proteins, vitamins, carbohydrates, fibers and minerals. However, some of their non-nutritive elements can present undesirable side effects like flatulence provoked by the anaerobic fermentation of oligosaccharides, such as raffinose and stachyose, in the gut. A way to avoid this inconvenience, without any change in the nutritional value and post-harvesting losses, is an irradiation process. Here, we evaluated the effects of gamma irradiation on the amino acids, thiamine and oligosaccharide contents and on the fungi and their toxin percentages in cowpea bean ( Vigna unguiculata L. Walp) samples. For irradiation doses of 0.0, 0.5, 1.0, 2.5, 5.0 and 10.0 kGy the results showed no significant differences in content for the uncooked samples. However, the combination of irradiation and cooking processes reduced the non-nutritive factors responsible for flatulence. Irradiation also significantly reduced the presence of Aspergillus, Penicilium, Rhizopus and Fusarium fungi and was shown to be efficient in grain conservation for a storage time of 6 months.

  9. Effect of gamma irradiation on the nutritional quality of Agaricus bisporus strains cultivated in different composts.

    PubMed

    Andrade, Meire C N; Jesus, João P F; Vieira, Fabrício R; Viana, Sthefany R F; Spoto, Marta H F; Minhoni, Marli T A

    2014-05-14

    The effect of irradiation doses (0, 125, 250 and 500 Gy) on the nutritional quality of A. bisporus mushrooms (strains ABI-07/06, ABI-05/03 and PB-1) cultivated in composts based on oat straw (Avena sativa) and brachiaria (Brachiaria sp.) was evaluated. The experimental design was 4 x 3 x 2 factorial scheme (irradiation doses x strains x composts), with 24 treatments, consisting of two repetitions each, totaling 48 experimental units (samples of mushrooms). The samples were irradiated in Cobalt-60 irradiator, model Gammacell 220 kGy, with dose rate of 0.740 kGy h-1, according to the treatments proposed. Subsequently, the control (unirradiated) and the other treatments were maintained at 4±1°C and 90% RH in a climatic chamber for carrying out the chemical analysis of the mushrooms on the 1st and 14th day of storage. It was found that all A. bisporus strains evaluated were food with excellent nutritional value, because they presented high protein and fiber contents and low ethereal extract content; the chemical characterization of the mushrooms was influenced by the compost type in which they were cultivated; gamma irradiation influenced the chemical composition of mushrooms.

  10. Electron spin resonance studies of free radicals in gamma-irradiated soybean paste.

    PubMed

    Lee, E J; Volkov, V I; Lee, C H

    2001-07-01

    Free radicals in gamma-irradiated soybean paste were investigated by electron spin resonance (ESR) spectroscopy to determine the effect of temperature (77-296 K) and moisture content (1-54%) of samples irradiated at high dose (1-40 kGy). The samples were kept in liquid nitrogen (77 K) during irradiation and subsequent ESR measurements. The spectra shown at 77 K consisted of the hydrogen atom lines at low and high field and complicated symmetric spectrum. By increasing the microwave power, the line shape of ESR spectra altered, which indicated the detection of different paramagnetic centers at different microwave powers. In saturation curves, it was possible to select four types of spectra components which were different in their relaxation times. By the different irradiation doses, the change in free radical concentration showed a curvilinearly increasing relationship with irradiation dose in wet samples, whereas a proportional relationship was observed with dried samples. This might indicate that the indirect process of free radical formation was involved with the existence of free water radicals in the wet samples.

  11. Degradation and annealing studies on gamma rays irradiated COTS PPD CISs at different dose rates

    NASA Astrophysics Data System (ADS)

    Wang, Zujun; Ma, Yingwu; Liu, Jing; Xue, Yuan; He, Baoping; Yao, Zhibin; Huang, Shaoyan; Liu, Minbo; Sheng, Jiangkun

    2016-06-01

    The degradation and annealing studies on Colbalt-60 gamma-rays irradiated commercial-off-the-shelf (COTS) pinned photodiode (PPD) CMOS image sensors (CISs) at the various dose rates are presented. The irradiation experiments of COTS PPD CISs are carried out at 0.3, 3.0 and 30.0 rad(Si)/s. The COTS PPD CISs are manufactured using a standard 0.18-μm CMOS technology with four-transistor pixel PPD architecture. The behavior of the tested CISs shows a remarkable degradation after irradiation and differs in the dose rates. The dark current, dark signal non-uniformity (DSNU), random noise, saturation output, signal to noise ratio (SNR), and dynamic range (DR) versus the total ionizing dose (TID) at the various dose rates are investigated. The tendency of dark current, DSNU, and random noise increase and saturation output, SNR, and DR to decrease at 3.0 rad(Si)/s are far greater than those at 0.3 and 30.0 rad(Si)/s. The damage mechanisms caused by TID irradiation at the various dose rates are also analyzed. The annealing tests are carried out at room temperature with unbiased conditions after irradiation.

  12. Gamma 60Co-irradiation of organic matter in the Phosphoria Retort Shale

    NASA Astrophysics Data System (ADS)

    Lewan, M. D.; Ulmishek, G. F.; Harrison, W.; Schreiner, F.

    1991-04-01

    Irradiation experiments were conducted on a thermally immature rock sample of the Phosphoria Retort Shale and its isolated kerogen. A 60Co-source for gamma radiation was employed at dosages ranging from 81 to 885 Mrads, which are attainable by Paleozoic and Precambrian black shales with syngenetic uranium enrichments. Kerogen elemental, isotopic, and pyrolysate compositions are not affected at these dosages, but the bitumens extracted from the irradiated rock are affected. The major effects are reductions in the amounts of bitumen, acyclic isoprenoids, and high-molecular weight acyclic carboxylic acids. Natural differences in the amounts of bitumen and acyclic isoprenoid due to regional and stratigraphie variations in organic source input and depositional conditions make the radiation-induced reductions in these parameters difficult to use as indicators of natural radiation damage in black shales. However, the preferential reduction in the high-molecular weight acyclic carboxylic acids, which are ubiquitous in the living precursory organic matter, is diagnostic of experimental γ-irradiation but may not be diagnostic of natural irradiation. The overall process associated with radiation damage is polymerization by cross-linking through a free radical mechanism. As a result, irradiation of organic matter in black shales is more likely to retard rather than enhance petroleum generation.

  13. Manufacture of ice cream with improved microbiological safety by using gamma irradiation

    NASA Astrophysics Data System (ADS)

    Lee, Ju-Woon; Kim, Hyun-Joo; Yoon, Yohan; Kim, Jae-Hun; Ham, Jun-Sang; Byun, Myung-Woo; Baek, Min; Jo, Cheorun; Shin, Myung-Gon

    2009-07-01

    Children suffered from leukemia want to eat delicious dishes, such as cake and ice cream. However, it is very difficult to serve these foods to immune-compromised patients without application of any adequate sanitary measures. This study was conducted to evaluate application of irradiation to frozen ready-to-eat food, ice cream. Three ice creams with flavors of vanilla, chocolate and strawberry were manufactured and gamma irradiated at the absorbed doses of 1, 3, and 5 kGy at -70 °C. Total microflora and coliform bacteria were determined, and Listeria spp., Escherichia coli and Salmonella spp. were also tested by the use of API 20E Kit. Aerobic bacteria, yeast/mold and coliforms were contaminated in the levels of 2.3 to 3.3, 2.3 to 2.7 and 1.7 to 2.4 log CFU/g, respectively. In samples irradiated at 5 kGy, the growth of any microorganisms could not be observed. Listeria spp. and E. coli were detected at non-irradiated samples, but S. spp. was not existed. D10 values of L. ivanovii and E. coli were 0.75 and 0.31 kGy, respectively, in ice cream. From these results, irradiation technology can reduce the risk by the food-borne pathogens of ice cream.

  14. Effect of gamma irradiation on the friction and wear of ultrahigh molecular weight polyethylene

    NASA Technical Reports Server (NTRS)

    Jones, W. R.; Hady, W. F.; Crugnola, A.

    1981-01-01

    The effect of sterilization gamma irradiation on the friction and wear properties of ultrahigh molecular weight polyethylene (UHMWPE) sliding against stainless steel 316L in dry air at 23 C is investigated, the results to be used in the development of artificial joints which are to surgically replace diseased human joints. A pin-on-disk sliding friction apparatus is used, a constant sliding speed in the range 0.061-0.27 m/s is maintained, a normal load of 1 kgf is applied with dead weight, and the irradiation dose levels are: 0, 2.5, and 5.0 Mrad. Wear and friction data and conditions for each of the ten tests are summarized, and include: (1) wear volume as a function of the sliding distance for the irradiation levels, (2) incremental wear rate, and (3) coefficient of friction as a function of the sliding distance. It is shown that (1) the friction and wear properties of UHMWPE are not significantly changed by the irradiation doses of 2.5 and 5.0 Mrad, (2) the irradiation increases the amount of insoluble gel as well as the amount of low molecular weight material, and (3) after run-in the wear rate is either steady or gradually decreases as a function of the sliding distance.

  15. Effects of gamma irradiation on different stages of mealybug Dysmicoccus neobrevipes (Hemiptera: Pseudococcidae)

    NASA Astrophysics Data System (ADS)

    The, Doan Thi; Khanh, Nguyen Thuy; Lang, Vo Thi Kim; Van Chung, Cao; An, Tran Thi Thien; Thi, Nguyen Hoang Hanh

    2012-01-01

    Utilization of phytosanitary irradiation as a potential treatment to disinfest agricultural commodities in trade has expanded rapidly in the recent years. Cobalt-60 gamma ray target doses of 100, 150, 200 and 250 Gy were used to irradiate immatures and adults of Dysmicoccus neobrevipes (Beardsley) (Hemiptera: Pseudococcidae) infesting dragon fruits to find the most tolerant stage and the most optimal dose range for quarantine treatment. In general, irradiation affected significantly all life stages of D. neobrevipes mortality and adult reproduction. The pattern of tolerance to irradiation in D. neobrevipes was 1st instars<2nd instars<3rd instarsirradiation, predicted doses for 100% mortality of each different development stage in the above mentioned pattern were 224.6, 241.3, 330.9 and 581.5 Gy, respectively. No survived female adult produced offspring at 200 and 250 Gy. Dose range between 200 and 250 Gy could be efficient to prevent the reproduction of this mealybug.

  16. Graphene scavenges free radicals to synergistically enhance structural properties in a gamma-irradiated polyethylene composite through enhanced interfacial interactions.

    PubMed

    Kolanthai, Elayaraja; Bose, Suryasarathi; Bhagyashree, K S; Bhat, S V; Asokan, K; Kanjilal, D; Chatterjee, Kaushik

    2015-09-21

    A unique strategy for scavenging free radicals in situ on exposure to gamma irradiation in polyethylene (PE) nanocomposites is presented. Blends of ultra-high molecular weight PE and linear low-density PE (PEB) and their nanocomposites with graphene (GPEB) were prepared by melt mixing to develop materials for biomedical implants. The effect of gamma irradiation on the microstructure and mechanical properties was systematically investigated. The neat blend and the nanocomposite were subjected to gamma-ray irradiation in order to improve the interfacial adhesion between PE and graphene sheets. Structural and thermal characterization revealed that irradiation induced crosslinking and increased the crystallinity of the polymer blend. The presence of graphene further enhanced the crystallinity via crosslinks between the polymer matrix and the filler on irradiation. Graphene was found to scavenge free radicals as confirmed by electron paramagnetic resonance spectroscopy. Irradiation of graphene-containing polymer composites resulted in the largest increase in modulus and hardness compared to either irradiation or addition of graphene to PEB alone. This study provides new insight into the role of graphene in polymer matrices during irradiation and suggests that irradiated graphene-polymer composites could emerge as promising materials for use as articulating surfaces in biomedical implants. PMID:26266702

  17. Graphene scavenges free radicals to synergistically enhance structural properties in a gamma-irradiated polyethylene composite through enhanced interfacial interactions.

    PubMed

    Kolanthai, Elayaraja; Bose, Suryasarathi; Bhagyashree, K S; Bhat, S V; Asokan, K; Kanjilal, D; Chatterjee, Kaushik

    2015-09-21

    A unique strategy for scavenging free radicals in situ on exposure to gamma irradiation in polyethylene (PE) nanocomposites is presented. Blends of ultra-high molecular weight PE and linear low-density PE (PEB) and their nanocomposites with graphene (GPEB) were prepared by melt mixing to develop materials for biomedical implants. The effect of gamma irradiation on the microstructure and mechanical properties was systematically investigated. The neat blend and the nanocomposite were subjected to gamma-ray irradiation in order to improve the interfacial adhesion between PE and graphene sheets. Structural and thermal characterization revealed that irradiation induced crosslinking and increased the crystallinity of the polymer blend. The presence of graphene further enhanced the crystallinity via crosslinks between the polymer matrix and the filler on irradiation. Graphene was found to scavenge free radicals as confirmed by electron paramagnetic resonance spectroscopy. Irradiation of graphene-containing polymer composites resulted in the largest increase in modulus and hardness compared to either irradiation or addition of graphene to PEB alone. This study provides new insight into the role of graphene in polymer matrices during irradiation and suggests that irradiated graphene-polymer composites could emerge as promising materials for use as articulating surfaces in biomedical implants.

  18. Effect of cumulated dose on hydrogen emission from polyethylene irradiated under oxidative atmosphere using gamma rays and ion beams

    NASA Astrophysics Data System (ADS)

    Ferry, M.; Pellizzi, E.; Boughattas, I.; Fromentin, E.; Dauvois, V.; de Combarieu, G.; Coignet, P.; Cochin, F.; Ngono-Ravache, Y.; Balanzat, E.; Esnouf, S.

    2016-01-01

    This work reports the effect of very high doses, up to 10 MGy, on the H2 emission from high density polyethylene (HDPE) irradiated with gamma rays and ion beams, in the presence of oxygen. This was obtained through a two-step procedure. First, HDPE films were pre-aged, at different doses, using either gamma rays or ion beams. In the second step, the pre-aged samples were irradiated in closed glass ampoules for gas quantification, using the same beam type as for pre-ageing. The hydrogen emission rate decreases when dose increases for both gamma rays and ion beams. However, the decreasing rate appears higher under gamma rays than under ion beam irradiations and this is assigned to a lesser oxidation level under the latter. Herein, we show the effectiveness of the radiation-induced defects scavenging effect under oxidative atmosphere, under low and high excitation densities.

  19. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor

    NASA Astrophysics Data System (ADS)

    Ranwa, Sapana; Singh Barala, Surendra; Fanetti, Mattia; Kumar, Mahesh

    2016-08-01

    We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor’s performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment.

  20. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor.

    PubMed

    Ranwa, Sapana; Barala, Surendra Singh; Fanetti, Mattia; Kumar, Mahesh

    2016-08-26

    We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor's performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment. PMID:27418478

  1. Gamma irradiation of 2-mercaptobenzothiazole aqueous solution in the presence of persulfate.

    PubMed

    Bao, Qiburi; Chen, Lujun; Tian, Jinping; Wang, Jianlong

    2016-08-01

    Recently, water treatment by ionizing radiation has gained increasing attention as a powerful technology for the destruction of refractory pollutants. 2-Mercaptobenzothiazole (MBT) is known as a widespread, toxic and poorly biodegradable pollutant. This paper studied the gamma irradiation of aqueous solutions of MBT. Moreover, the effect of the addition of persulfate (S2O8(2-)) on the radiolytic destruction of MBT was investigated. The main transformation products of the studied compound were detected and the sequence of occurrence of the products was described. The change of biodegradability of MBT solution was also observed. The main results obtained in this study indicated that gamma radiation was effective for removing MBT in aqueous solution. Persulfate addition, which induced the formation of reactive sulfate radicals (SO4(-)), greatly enhanced the degradation of MBT. Benzothiazole was identified as the first radiation product, followed by 2-hydroxybenzothiazole. Decomposition of MBT started with the oxidation of -SH groups to sulfate ions. Possible pathways for MBT decomposition by gamma irradiation were proposed. The BOD/COD ratios of MBT samples were increased after radiation, indicating the improvement of biodegradability and reduction of toxicity. PMID:27521957

  2. Fractography evolution in accelerated aging of UHMWPE after gamma irradiation in air.

    PubMed

    Medel, F; Gómez-Barrena, E; García-Alvarez, F; Ríos, R; Gracia-Villa, L; Puértolas, J A

    2004-01-01

    We studied the fracture surface evolution of ultra high molecular weight polyethylene (UHMWPE) specimens, manufactured from GUR 1050 compression moulded sheets, after gamma sterilisation in air followed by different aging times after thermal treatment at 120 degrees C. Degradation profiles were obtained by FTIR and DSC measurements after 0, 7, 14, 24 and 36h aging. We observed by SEM the morphology patterns at these aging times, in surface fractographies after uniaxial tensile test of standardised samples. The results pointed out clear differences between short and long aging times. At shorter times, 7h, the behaviour was similar to non-degraded UHMWPE, exhibiting ductile behaviour. At longer times, 24-36h, this thermal protocol provided a highly degraded zone in the subsurface, similar to the white band found after gamma irradiation in air followed by natural aging, although closer to the surface, at 150-200mum. The microstructure of this oxidation zone, similarly found in gamma irradiated samples shelf-aged for 6-7 years, although with different distribution of microvoids, was formed by fibrils, associated with embrittlement of the oxidised UHMWPE. In addition, the evolution of the oxidation index, the enthalpy content, the mechanical parameters, and the depth of the oxidation front deduced from the fractographies versus aging time showed that a changing behaviour in the degradation rate appeared at intermediate aging times.

  3. Sterilization of allograft bone: is 25 kGy the gold standard for gamma irradiation?

    PubMed

    Nguyen, Huynh; Morgan, David A F; Forwood, Mark R

    2007-01-01

    For several decades, a dose of 25 kGy of gamma irradiation has been recommended for terminal sterilization of medical products, including bone allografts. Practically, the application of a given gamma dose varies from tissue bank to tissue bank. While many banks use 25 kGy, some have adopted a higher dose, while some choose lower doses, and others do not use irradiation for terminal sterilization. A revolution in quality control in the tissue banking industry has occurred in line with development of quality assurance standards. These have resulted in significant reductions in the risk of contamination by microorganisms of final graft products. In light of these developments, there is sufficient rationale to re-establish a new standard dose, sufficient enough to sterilize allograft bone, while minimizing the adverse effects of gamma radiation on tissue properties. Using valid modifications, several authors have applied ISO standards to establish a radiation dose for bone allografts that is specific to systems employed in bone banking. These standards, and their verification, suggest that the actual dose could be significantly reduced from 25 kGy, while maintaining a valid sterility assurance level (SAL) of 10(-6). The current paper reviews the methods that have been used to develop radiation doses for terminal sterilization of medical products, and the current trend for selection of a specific dose for tissue banks. PMID:16821106

  4. Identification of estrogenic activity change in sewage, industrial and livestock effluents by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Ahn, Byeong-Yong; Kang, Sung-Wook; Yoo, Jisu; Kim, Woong-Ki; Bae, Paek-Hyun; Jung, Jinho

    2012-11-01

    In this study, reduction of estrogenic activity in three different types of effluents from sewage, industrial and livestock wastewater treatment plants by gamma-irradiation was investigated using the yeast two-hybrid assay. After gamma-ray treatment at a dose of 10 kGy, estrogenic activities of sewage, industrial and livestock effluents decreased from 4.4 to 3.0, 1.5 to 1.0 and 16 to 9.9 ng-EEQ L-1, respectively. The substantial reduction of estrogenic activity in livestock effluent was attributable to the degradation of 17β-estradiol (E2), estrone (E1) and 17α-ethynylestradiol (EE2). Although bisphenol A (BPA) was found at the highest concentration in all effluents, its contribution to the estrogenic activity was not significant due to its low relative estrogenic potency. Meanwhile, the calculated estrogenic activity based on concentrations of E2, E1, EE2 and BPA in the effluents significantly differed from the measured ones. Overestimation may have resulted by dissolved organic matters in effluents inhibiting the estrogenic activity of E2, E1, EE2 and BPA, whereas underestimation was likely due to estrogenic by-products generated by gamma-irradiation.

  5. Influence of sterilization by gamma irradiation and of thermal annealing on creep of hydroxyapatite-reinforced polyethylene composites.

    PubMed

    Suwanprateeb, J; Tanner, K E; Turner, S; Bonfield, W

    1998-01-01

    Sterilization of medical devices by gamma (gamma)-irradiation is common. The effect of irradiation on a bone replacement material, HAPEX (hydroxyapatite-reinforced polyethylene composite), was investigated. Unfilled and hydroxyapatite-filled polyethylene at 0.20 and 0.40 filler volume fractions were gamma-irradiated at 2.5 Mrad, and the modified properties were studied by differential scanning calorimetery, isochronous experiments, and creep tests. The effect of thermal annealing of the samples from 140 degrees C also was examined. The results suggest that both irradiation and annealing increase creep resistance of the materials. These are associated with the formation of crosslinks and an increase in crystallinity, respectively. PMID:9429092

  6. Effect of gamma irradiation on chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils

    NASA Astrophysics Data System (ADS)

    Zantar, Said; Haouzi, Rachid; Chabbi, Mohamed; Laglaoui, Amin; Mouhib, Mohammed; Mohammed Boujnah; Bakkali, Mohammed; Zerrouk, Mounir Hassani

    2015-10-01

    The effects of gamma irradiation doses (10, 20 and 30 kGy) on chemical composition, antimicrobial and antioxidant activities of Thymus vulgaris and Mentha pulegium essential oils (EOs) have been studied. The chromatographic analysis showed that the studied EOs were constituted mainly by carvacrol for T. vulgaris and pulegone for M. pulegium. Gamma irradiation on the studied doses, affects quantitatively and not qualitatively some components of the investigated oils. This effect was dose dependent. While the antioxidant activity remains stable at any dose applied for the plants studied, the antimicrobial activity increased in the irradiated samples for gram negative bacteria and did not change for gram+bacteria. This study supports that gamma irradiation employed at sterilizing doses did not compromise the biological activities of medicinal and aromatic plants.

  7. Detection of gamma-irradiation induced DNA damage and radioprotection of compounds in yeast using comet assay.

    PubMed

    Nemavarkar, P S; Chourasia, B K; Pasupathy, K

    2004-06-01

    The single cell gel electrophoresis assay (SCGE), a very rapid and sensitive method, has been applied to follow gamma-irradiation induced DNA damage in budding yeast, Saccharomyces cerevisiae. Spheroplasting the gamma-irradiated yeast cells by enzyme glusulase, before subjecting them to electrophoresis, resulted in a well-defined appearance of comets. Yeast comets look quite different from mammalian comets. A linear relationship was observed between the doses of irradiation and the tail moments of comets. These studies were extended to follow the action of known radio-protectors, i.e., caffeine and disulfiram. The results revealed the usefulness SCGE as applied to yeast in studies of the gamma-irradiation-induced DNA breaks and also radio-protection by chemicals at doses that are not feasible with other eukaryotes. PMID:15304956

  8. Quantitative comparison of wear debris from UHMWPE that has and has not been sterilised by gamma irradiation.

    PubMed

    Besong, A A; Tipper, J L; Ingham, E; Stone, M H; Wroblewski, B M; Fisher, J

    1998-03-01

    Ultra-high-molecular-weight polyethylene (UHMWPE) components for total joint replacement generate wear particles which cause adverse biological tissue reactions leading to osteolysis and loosening. Sterilisation of UHMWPE components by gamma irradiation in air causes chain scissions which initiate a long-term oxidative process that degrades the chemical and mechanical properties of the polyethylene. Using a tri-pin-on-disc tribometer we studied the effect of ageing for ten years after gamma irradiation in air on the volumetric wear, particle size distribution and the number of particles produced by UHMWPE when sliding against a stainless-steel counterface. The aged and irradiated material produced six times more volumetric wear and 34 times more wear particles per unit load per unit sliding distance than non-sterilised UHMWPE. Our findings indicate that oxidative degradation of polyethylene after gamma irradiation in air with ageing produces more wear.

  9. Antibacterial silver nanoparticles in polyvinyl alcohol/sodium alginate blend produced by gamma irradiation.

    PubMed

    Eghbalifam, Naeimeh; Frounchi, Masoud; Dadbin, Susan

    2015-09-01

    Polyvinyl alcohol/sodium alginate/nano silver (PVA/SA/Ag) composite films were made by solution casting method. Gamma irradiation was used to synthesize silver nanoparticles in situ via reduction of silver nitrate without using harmful chemical agents for biomedical applications. UV-vis and XRD results demonstrated that spherical silver nanoparticles were produced even at low irradiation dose of 5 kGy. By increasing irradiation dose, more nanoparticles were synthesized while no PVA hydrogel was formed up to 15 kGy. Also the size of nanoparticles was reduced with increasing gamma dose evidenced by higher release rate of silver nanoparticles in lukewarm water and SEM images. Comparing SEM images with DLS results indicated good performance of PVA/SA as an efficient stabilizer in preventing agglomeration of the silver nanoparticles. Good miscibility of polyvinyl alcohol and sodium alginate observed on the SEM images was supported with FTIR spectroscopy. Upon addition of sodium alginate to polyvinyl alcohol and increasing silver nanoparticles, the melting peak shifted to lower temperature and crystallinity percent was decreased. Addition of sodium alginate led to remarkable increase in rigidity of PVA. The composites exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli even at very low level of silver nanoparticles. PMID:26123816

  10. Reaction of glass during gamma irradiation in a saturated tuff environment. Part 1. SRL 165 glass

    SciTech Connect

    Bates, J.K.; Fischer, D.F.; Gerding, T.J.

    1986-02-01

    The influence of gamma irradiation on the reaction of actinide-doped borosilicate glass (SRL 165) in a saturated tuff environment has been studied in a series of tests lasting up to 56 days. The following conclusions were reached. The reaction of, and subsequent actinide release from, the glass depends on the dynamic interaction between radiolysis effects, which cause the solution pH to become more acidic; glass reaction, which drives the pH more basic; and test component interactions that may extract glass components from solution. The use of large gamma irradiation dose rates to accelerate reactions that may occur in an actual repository radiation field may affect this dynamic balance by unduly influencing the mechanism of the glass-water reaction. Comparisons between the present results and data obtained by reacting similar glasses using MCC-1 and NNWSI rock cup procedures indicate that the irradiation conditions used in the present experiments do not dramatically influence the reaction rate of the glass. 8 figs., 9 tabs.

  11. Antibacterial silver nanoparticles in polyvinyl alcohol/sodium alginate blend produced by gamma irradiation.

    PubMed

    Eghbalifam, Naeimeh; Frounchi, Masoud; Dadbin, Susan

    2015-09-01

    Polyvinyl alcohol/sodium alginate/nano silver (PVA/SA/Ag) composite films were made by solution casting method. Gamma irradiation was used to synthesize silver nanoparticles in situ via reduction of silver nitrate without using harmful chemical agents for biomedical applications. UV-vis and XRD results demonstrated that spherical silver nanoparticles were produced even at low irradiation dose of 5 kGy. By increasing irradiation dose, more nanoparticles were synthesized while no PVA hydrogel was formed up to 15 kGy. Also the size of nanoparticles was reduced with increasing gamma dose evidenced by higher release rate of silver nanoparticles in lukewarm water and SEM images. Comparing SEM images with DLS results indicated good performance of PVA/SA as an efficient stabilizer in preventing agglomeration of the silver nanoparticles. Good miscibility of polyvinyl alcohol and sodium alginate observed on the SEM images was supported with FTIR spectroscopy. Upon addition of sodium alginate to polyvinyl alcohol and increasing silver nanoparticles, the melting peak shifted to lower temperature and crystallinity percent was decreased. Addition of sodium alginate led to remarkable increase in rigidity of PVA. The composites exhibited strong antibacterial activity against Staphylococcus aureus and Escherichia coli even at very low level of silver nanoparticles.

  12. Cationization and gamma irradiation effects on the dyeability of polyester fabric towards disperse dyes

    NASA Astrophysics Data System (ADS)

    Zohdy, Maged H.

    2005-06-01

    The effect of hydrazine hydrate (HZH) treatment and/or gamma irradiation on the dyeing, mechanical and thermal properties of polyester fabrics (PET) was studied. The different factors that may affect the dyeing performance, such as concentrations of HZH, benzyl alcohol and pH values, were investigated. In this regard, the colour strength of untreated polyester fabrics dyed with the dyestuffs Dispersol blue BR, Dispersol orange B2R and Dispersol red B2B was found to be 10.34, 10.76 and 10.12 compared to 24.61, 24.90 and 23.00 in the case of irradiated and HZH-treated polyester fabrics, respectively. These colour strength values were achieved by preirradiation at a dose of 75 kGy followed by treatment with 15 ml l-1 of HZH. Thermogravimetric analysis (TGA) showed that the thermal decomposition stability was improved by using gamma irradiation and the treatment with HZH as indicated by the calculated activation energies. FT-IR spectroscopy showed that the treatment with HZH acts as cationizer prior to dyeing with disperse dyes.

  13. Electron magnetic resonance study of gamma-irradiated poly(lactide-co-glycolide) microspheres.

    PubMed

    Claybourn, Mike; Gray, Helen; Murphy, Damien M; Purnell, Ian J; Rowlands, Christopher C

    2003-09-01

    A series of poly(lactide-co-glycolide) samples of compositions ranging from (75:25) to (65:35) to (50% (65:35):50% (50:50)) were gamma-irradiated under ambient conditions in air. The irradiation doses used were 15, 20, 25, and 30 kGy. The generation of radicals resulting from the gamma-irradiation was confirmed using EPR. Two major radical species were observed and identified as centered at alkyl and alkyl peroxy groups. The indication from the X-band (9 GHz) frequencies showed that alkyl radicals gave rise to a quartet hyperfine pattern. However, measurements performed at higher W-band frequencies (90 GHz) showed that the X-band spectra are actually a composite profile arising from a series of overlapping individual resonances. Using combined EPR and ENDOR (Electron-Nuclear DOuble Resonance) measurements, an alkyl peroxy radical was identified. For increasing glycolide concentration from 75:25 to the 50:50 blend, there was a factor of 7 increase in the concentration of radicals A and B. Furthermore, both radical species were found to be stable for several weeks after storage at ambient temperature conditions. At elevated temperatures and humidities, radical stability decreased--the decay rate was estimated at approximately 3x10(-8) mol K(-1). The stability characteristics of the radicals under different conditions are attributed to changes in the morphology of the polymer. PMID:12932720

  14. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    NASA Astrophysics Data System (ADS)

    Evora, M. C.; Araujo, J. R.; Ferreira, E. H. M.; Strohmeier, B. R.; Silva, L. G. A.; Achete, C. A.

    2015-04-01

    Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO4·7H2O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

  15. Effect of gamma irradiation on opto-structural, dielectric, and thermoluminescence properties of natural phlogopite mica

    SciTech Connect

    Kaur, Sukhnandan; Singh, Surinder; Singh, Lakhwant; Lochab, S. P.

    2013-09-07

    Gamma ray induced modifications in natural phlogopite mica have been studied in the dose range of 1–2000 kGy. These modifications were monitored using different techniques viz: ultraviolet-visible spectroscopy, Fourier Transform Infrared spectroscopy, dielectric measurements, X-ray diffraction, and thermoluminescence dosimeter. The analysis of the results reveals that the dose of 100 kGy produces significant change in the natural phlogopite mica as compared to pristine and other exposed samples. Ultraviolet-visible analysis provides the value of optical indirect, direct band gap, and Urbach energy. Cody model was used to calculate structural disorder from Urbach energy. Different dielectric parameters such as dielectric constant, dielectric loss, ac conductivity, and real and imaginary parts of electric modulus were calculated for pristine and irradiated samples at room temperature. Williamson Hall analysis was employed to calculate crystallite size and micro-strain of pristine and irradiated sheets. No appreciable changes in characteristic bands were observed after irradiation, indicating that natural phlogopite mica is chemically stable. The natural phlogopite mica may be recommended as a thermoluminescent dosimeter for gamma dose within 1 kGy–300 kGy.

  16. Gamma irradiation for terminal sterilization of 17beta-estradiol loaded poly-(D,L-lactide-co-glycolide) microparticles.

    PubMed

    Mohr, D; Wolff, M; Kissel, T

    1999-08-27

    17beta-Estradiol-loaded microparticles using poly-(D, L-lactide-co-glycolide) polymer (PLG) were prepared by a modified spray-drying method and the effects of gamma-irradiation on drug substance, polymer and microparticles were investigated. Irradiation doses ranging from 5.1 to 26.6 kGy were applied using a 60Co-radiation source. 17beta-Estradiol drug substance showed excellent stability against gamma-irradiation in the investigated dose range, whereas microencapsulated estradiol seems to be converted to conjugation products with PLG, and to a lesser extent to the degradation product 9,11-dehydroestradiol. The weight-average molecular weight of the PLG polymers decreased with increasing irradiation dose while polydispersity indices (M(w)/M(n)) remained nearly unchanged, compatible with a random chain scission mechanism in lactide/glycolide-copolymer degradation. In vitro drug release studies showed accelerated kinetics with increasing irradiation doses due to dose dependent polymer degradation. Microbiological process monitoring showed decreasing bioburden with increasing spraying time, which was successfully further reduced by applying irradiation sterilization. Microencapsulated test spore suspensions of Bacillus pumilus ATCC 27142, the official test specimen for the gamma-sterilization process, revealed effective reduction of bioburden, confirming its published D(10) value. In conclusion, our studies demonstrated efficacy of gamma-irradiation as terminal sterilization method for poly-(D,L-lactide-co-glycolide) polymer-based drug delivery systems. The sterilization conditions need to be carefully adjusted for the final dosage form. PMID:10469916

  17. Gamma Irradiation Facility at Sandia National Laboratories, Albuquerque, New Mexico. Final environmental assessment

    SciTech Connect

    1995-11-01

    The US Department of Energy (DOE) has prepared an environmental assessment (EA) on the proposed construction and operation of a new Gamma Irradiation Facility (GIF) at Sandia National Laboratories/New Mexico (SNL/NM). This facility is needed to: enhance capabilities to assure technical excellence in nuclear weapon radiation environments testing, component development, and certification; comply with all applicable ES and H safeguards, standards, policies, and regulations; reduce personnel radiological exposure to comply with ALARA limits in accordance with DOE orders and standards; consolidate major gamma ray sources into a central, secured area; and reduce operational risks associated with operation of the GIF and LICA in their present locations. This proposed action provides for the design, construction, and operation of a new GIF located within TA V and the removal of the existing GIF and Low Intensity Cobalt Array (LICA). The proposed action includes potential demolition of the gamma shield walls and removal of equipment in the existing GIF and LICA. The shielding pool used by the existing GIF will remain as part of the ACRR facility. Transportation of the existing {sup 60}Co sources from the existing LICA and GIF to the new facility is also included in the proposed action. Relocation of the gamma sources to the new GIF will be accomplished by similar techniques to those used to install the sources originally.

  18. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  19. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    SciTech Connect

    Schwarze, G.E.; Frasca, A.J.

    1994-09-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10{sup 13} n/cm {sup 2} and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  20. Optical properties of gamma irradiated soda-lime silicate glasses exchanged with copper

    NASA Astrophysics Data System (ADS)

    Macalik, B.

    2003-01-01

    The effect of copper ion exchange upon the optical absorption and room temperature gamma colouration of soda lime silicate glasses has been investigated. After ion exchange performed at 720 K, copper ions substitute mainly the alkali ions and do modify the optical absorption spectra of the specimens. It has been shown that gamma irradiation does not induce the formation of colloidal copper. Moreover, the colouration process itself is independent of the presence of copper ions. The generated colour centres are rather related to the presence of sodium and potassium ions. The optical bleaching by the UV light occurs in two stages. First disappear centres related to the Na-type defects and next those related to the K-type defects.

  1. Antioxidant activities of fucoidan degraded by gamma irradiation and acidic hydrolysis

    NASA Astrophysics Data System (ADS)

    Lim, Sangyong; Choi, Jong-il; Park, Hyun

    2015-04-01

    Low molecular weight fucoidan, prepared by radical degradation using gamma ray was investigated for its antioxidant activities with different assay methods. As the molecular weight of fucoidan decreased with a higher absorbed dose, ferric-reducing antioxidant power values increased, but β-carotene bleaching inhibition did not change significantly. The antioxidant activity of acid-degraded fucoidan was also examined to investigate the effect of different degradation methods. At the same molecular weight, fucoidan degraded by gamma irradiation showed higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity than that observed with the acidic method. This result reveals that in addition to molecular weight, the degradation method affects the antioxidant activity of fucoidan.

  2. Characterization of PE-g-HEMA films prepared by gamma irradiation through nuclear microprobe techniques

    NASA Astrophysics Data System (ADS)

    Ferreira, L. M.; Leal, J. P.; Rodrigues, P. A.; Alves, L. C.; Falcão, A. N.; Gil, M. H.

    2012-09-01

    PE-g-HEMA films with different grafting yields prepared by mutual gamma irradiation method at a 60Co source were characterized with ion beam analytical techniques using a nuclear microprobe. Qualitative analysis showed a random and heterogeneous distribution of contaminant elements, independent of the grafting degree, suggesting the existence of several sources of contamination at different stages of their preparation. Results also suggest that this "phased" contamination occurs simultaneously with mechanisms of agglomeration/entrapment of impurities during the gamma induced copolymerization reaction. Moreover, quantitative data showed that all contaminants found in the copolymeric films are natural contaminants of their reagents of preparation, although at concentrations without toxicological hazard, which points to a low cytotoxic potential.

  3. Effect of gamma irradiation on microbial load, physicochemical and sensory characteristics of soybeans (Glycine max L. Merrill)

    NASA Astrophysics Data System (ADS)

    Yun, Juan; Li, Xihong; Fan, Xuetong; Tang, Yao; Xiao, Yao; Wan, Sen

    2012-08-01

    Gamma irradiation is highly effective in inactivating microorganisms in various foods and offers a safe alternative method of food decontamination. In the present study, soybeans (Glycine max L. Merrill) were treated with 0, 1.0, 3.0, 5.0 and 10.0 KGy of gamma irradiation. Microbial populations on soybeans, isoflavone, tocopherol contents, raffinose family oligosaccharides, color and sensory properties were evaluated as a function of irradiation dose. The results indicated that gamma irradiation reduced aerobic bacterial and fungal load. Irradiation at the doses applied did not cause any significant change (p>0.05) in the contents of isoflavone of soybeans, but decreased tocopherol contents. The content of key flatulence-producing raffinose family oligosaccharides in irradiated soybeans (10.0 kGy) decreased by 82.1% compared to the control. Sensory analysis showed that the odor of the soybeans was organoleptically acceptable at doses up to 5.0 kGy and no significant differences were observed between irradiated and nonirradiated samples in flavor, texture and color after irradiation.

  4. Viruslike particles in the tissues of normal and gamma-irradiated Drosophila melanogaster.

    NASA Technical Reports Server (NTRS)

    Miquel, J.; Bensch, K. G.; Philpott, D. E.

    1972-01-01

    A new finding of viruslike particles in the salivary and accessory glands, muscles, and nerves of normal and gamma-irradiated Drosophila melanogaster is discussed. In morphology and size, the particles seemed identical to those described in earlier reports. On the basis of the available results, it cannot be affirmed that these particles infect only dividing cells, since they are found in all the Drosophila tissues so far examined. Their relation to the aging process is felt to be an interesting subject for further study.

  5. [Behavior of cats following gamma-irradiation of the head: the induced pleasure test].

    PubMed

    Davydov, B I; Ushakov, I B; Razgovorov, B L

    1985-01-01

    A decrease in the degree of manifestation of the induced pleasure response of male cats to the administration of valerian tincture was observed during the first 1-2 h following gamma-irradiation of the head with a dose of 1.29 C/kg. It is suggested that the absence of the reaction during the first 10-15 min after exposure is indicative of the presence of the phase of a pronounced excitation in the C.N.S. of the exposed animals. PMID:3975366

  6. Inactivation of mildew in rough rice and wheat by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Yu, Yong

    2010-06-01

    Rough rice and wheat were irradiated by gamma ray ( 60Co) with different doses and the mildew inactivation efficacy was investigated after 0, 6 and 12 month storage. Five genera of mildew in rough rice and wheat were detected, including Alternaria, Fusarium, Aspergillus, Penicillium and Rhizopus. For Aspergillus, four genera of mold were detected, including Aspergillus Kawachii, Aspergillus glaucus, Aspergillus niger, Aspergillus flavus. Detection rates of the five genera of mildew and four genera of Aspergillus were all reduced with increasing dose after 0, 6 and 12 months storage. The detection rates of the other four genera of mildew had no significant change during storage.

  7. The effect of gamma irradiation on the viscosity of two barley cultivars for broiler chicks

    NASA Astrophysics Data System (ADS)

    Al-Kaisey, Mahdi T.; Mohammed, Mahmoud A.; Alwan, Abdul-Kader H.; Mohammed, Manal H.

    2002-03-01

    Seeds of two barley cultivars (Local Black and Shoaa) were gamma irradiated at 0, 10, 50, 100, 150 and 200 kGy doses using Cobalt-60 source to decrease the viscosity. The viscosity was determined in the flour of the seeds using Ostwald U-tube viscometer. The viscosity values were reduced by 25%, 50%, 65%, 72% and 74% in Local Black barley cultivar, while, in Shoaa cultivar the reductions were 15%, 30%, 52%, 69% and 67% at 10, 50, 100, 150 and 200 kGy, respectively. The chemical compositions of the seeds were determined in all treatments.

  8. State of synapses of the cortex of cerebral hemispheres on gamma-irradiation

    SciTech Connect

    Gaidamakin, N.A.; Ushakov, I.B.

    1989-11-01

    In adult rats with developing neurological disorders we detected destructive changes in most of the synapses of the brain sensorimotor cortex 1.6-4.3 h after a single dose of gamma-irradiation (200 Gy). All functionally important parts on the axonal and dendritic sides of the synapses had undergone changes: mitochondria, synaptic vesicles, pre- and postsynaptic membranes, synaptic complexes, and subsynaptic consolidations, axonal and dendritic plasma, and their inclusions. These changes possibly cause disconnection of the neurons and provide a structural basis for neurological deficiencies following a high substantial ionizing radiation.

  9. Alpha particles are extremely damaging to developing hemopoiesis compared to gamma irradiation.

    PubMed

    Jiang, T N; Lord, B I; Hendry, J H

    1994-03-01

    Estimates of risk of stochastic effects from contamination with alpha-particle-emitting radionuclides are based on equivalent doses which take into account the RBE of the high-LET radiation. ICRP has recommended a dose-weighting factor, wR, of 20 for alpha-particle radiation. It is assumed that the RBEs for deterministic effects are considerably less than those for stochastic effects. However, the offspring of mice injected with 30 Bq g-1 239Pu at 13 days gestation develop a persistent deficit in hemopoietic stem cells which is primarily the result of damage to their regulatory microenvironment. Their spatial distribution in the marrow is also perturbed, and recent observations on those mice suggested a considerably higher factor than 20. To define a more realistic RBE for hemopoiesis, the effects of external gamma irradiation during the fetal development period have been compared directly with those of 239Pu incorporated via placental transfer on the development of hemopoietic tissue. Pregnant mice were irradiated with 60Co gamma rays (a) continuously from day 13 of gestation to birth at 0.15 or 0.6 Gy/day; (b) six repeated acute doses (0.6 Gy/min) at 0.1 or 0.3 Gy from day 13 of gestation; (c) one acute dose of 0.6 or 1.8 Gy on day 15 of gestation. The spatial distribution of hemopoietic stem cells in 8-week-old offspring was then determined and compared to that resulting from alpha-particle irradiation. In each case, the higher dose was required to match the results for alpha particles, suggesting an RBE for developing hemopoiesis of 250-360 compared to a continuous gamma-ray dose and a rather lower value of 130-180 compared to a single acute dose of gamma rays. This contrasts greatly to values for direct irradiation of the stem cells but argues that the effective RBE, measured for long-term effects in vivo, is the more realistic. It is concluded that an all-embracing factor can be grossly misleading in the specification of protection guidelines and can greatly

  10. Comparison of different chlorophenols degradation in aqueous solutions by gamma irradiation under reducing conditions

    NASA Astrophysics Data System (ADS)

    Peng, Yunxia; He, Shijun; Wang, Jianlong; Gong, Wenqi

    2012-10-01

    The reductive degradation of chlorophenols (CPs), including 2-CP, 4-CP and 2,4-DCP by gamma irradiation was investigated and compared. The results showed that the most efficient degradation took place with 2,4-DCP, followed by 2-CP and then 4-CP. This confirmed that the number and position of chlorine atoms existing in the benzene ring have significant impact on dechlorination and decomposition of CPs. The G-values of decomposition of CPs, the formation of intermediate products and chloride ion, and the degradation rate (KCPs and K) were also determined.

  11. Ionic conductivity and dielectric relaxation in {gamma}-irradiated TlGaTe{sub 2} crystals

    SciTech Connect

    Sardarli, R. M. Samedov, O. A.; Abdullayev, A. P.; Huseynov, E. K.; Salmanov, F. T.; Alieva, N. A.; Agaeva, R. Sh.

    2013-05-15

    The switching effect, field and temperature dependences of the permittivity and conductivity of TlGaTe{sub 2} crystals subjected to various {gamma}-irradiation doses are studied. Under rather low electric fields, the phenomenon of threshold switching with an S-shaped current-voltage characteristic containing a portion with negative differential resistance is observed in the crystals. In the region of critical voltages, current and voltage oscillations and imposed modulation are observed. Possible mechanisms of switching, ionic conductivity, disorder, and electrical instability in TlGaTe{sub 2} crystals are discussed.

  12. Transfection-mediated cell synchronization: acceleration of G1-S phase transition by gamma irradiation.

    PubMed

    Jung, E J; Flemington, E K

    2001-11-01

    We have previously provided evidence that the uptake of DNA into cells is cell cycle specific following transfection. We show here that, immediately after transfection, successfully transfected cells are greatly enriched for cells in early G1 or G0 phase and that, upon removal of the DNA precipitates, cells progress through G1 and enter S phase in a synchronous fashion. We also demonstrate that this approach can be utilized in meaningful cell-cycle experiments, and we show that gamma irradiation accelerates the G1-S phase transition in a cell line with a functionally inactive p53 protein. PMID:11730009

  13. Effects of gamma irradiation for inactivating Salmonella Typhimurium in peanut butter product during storage.

    PubMed

    Ban, Ga-Hee; Kang, Dong-Hyun

    2014-02-01

    Three types (A, B, and C) of peanut butter product with different water activities (0.18, 0.39, and 0.65 aw) inoculated with a 3-strain mixture of Salmonella Typhimurium were subjected to gamma irradiation (⁶⁰Co) treatment, with doses ranging from 0 to 3 kGy. The inactivation of S. Typhimurium in the 3 types of treated peanut butter product over a 14 day storage period and the influence of storage temperature at 4 (refrigerated) and 25 °C (ambient), and peanut butter product formulation were investigated. Three types of peanut butter product inoculated with S. Typhimurium to a level of ca. 6.6 log CFU/g and subjected to gamma irradiation experienced significant (p<0.05) reductions of 1.3 to 1.9, 2.6 to 2.8, and 3.5 to 4.0 log CFU/g at doses of 1, 2, and 3 kGy, respectively. The time required to reduce S. Typhimurium in peanut butter product to undetectable levels was 14, 5, and 5 days at 25°C after exposure to 3 kGy for products A, B, and C, respectively, and 7 days at 25 °C following exposure to 2 kGy for product C. During storage at 4 and 25 °C, survival of S. Typhimurium was lowest in product C compared to products A and B. Water activity (a(w)) of peanut butter product was likely the most critical factor affecting pathogen survival. When a(w) is reduced, radiolysis of water is reduced, thereby decreasing antimicrobial action. Overall, death was more rapid at 25 °C versus 4 °C for all peanut butter products during 14 day storage. Following gamma irradiation, acid values of peanut butter product were not significantly different from the control, and general observations failed to detect changes in color and aroma, even though lightness observed using a colorimeter was slightly reduced on day 0. The use of gamma irradiation has potential in preventing spoilage of post-packaged food by destroying microorganisms and improving the safety and quality of foods without compromising sensory quality.

  14. Effects of gamma irradiation for inactivating Salmonella Typhimurium in peanut butter product during storage.

    PubMed

    Ban, Ga-Hee; Kang, Dong-Hyun

    2014-02-01

    Three types (A, B, and C) of peanut butter product with different water activities (0.18, 0.39, and 0.65 aw) inoculated with a 3-strain mixture of Salmonella Typhimurium were subjected to gamma irradiation (⁶⁰Co) treatment, with doses ranging from 0 to 3 kGy. The inactivation of S. Typhimurium in the 3 types of treated peanut butter product over a 14 day storage period and the influence of storage temperature at 4 (refrigerated) and 25 °C (ambient), and peanut butter product formulation were investigated. Three types of peanut butter product inoculated with S. Typhimurium to a level of ca. 6.6 log CFU/g and subjected to gamma irradiation experienced significant (p<0.05) reductions of 1.3 to 1.9, 2.6 to 2.8, and 3.5 to 4.0 log CFU/g at doses of 1, 2, and 3 kGy, respectively. The time required to reduce S. Typhimurium in peanut butter product to undetectable levels was 14, 5, and 5 days at 25°C after exposure to 3 kGy for products A, B, and C, respectively, and 7 days at 25 °C following exposure to 2 kGy for product C. During storage at 4 and 25 °C, survival of S. Typhimurium was lowest in product C compared to products A and B. Water activity (a(w)) of peanut butter product was likely the most critical factor affecting pathogen survival. When a(w) is reduced, radiolysis of water is reduced, thereby decreasing antimicrobial action. Overall, death was more rapid at 25 °C versus 4 °C for all peanut butter products during 14 day storage. Following gamma irradiation, acid values of peanut butter product were not significantly different from the control, and general observations failed to detect changes in color and aroma, even though lightness observed using a colorimeter was slightly reduced on day 0. The use of gamma irradiation has potential in preventing spoilage of post-packaged food by destroying microorganisms and improving the safety and quality of foods without compromising sensory quality. PMID:24321602

  15. Structural investigations of bismuth lead borosilicate glasses under the influence of gamma irradiation through ultrasonic studies

    NASA Astrophysics Data System (ADS)

    Bootjomchai, Cherdsak; Laopaiboon, Jintana; Laopaiboon, Raewat

    2012-04-01

    The ultrasonic velocity measurements for different compositions of irradiated bismuth lead borosilicate glasses xBi2O3-(50-x)PbO-20B2O3-30SiO2 (x=2, 4, 6, 8, and 10 mol.%) were performed at room temperature using pulse-echo technique. Densities of glass samples were measured by Archimedes' principle using n-hexane as the immersion liquid. The results from the studies show that ultrasonic velocity, elastic moduli, Poisson's ratio, microhardness, and the Debye temperature increase with increasing bismuth oxide content and increasing gamma-radiation dose (3-12 Gy).

  16. Low survival of mice following lethal gamma-irradiation after administration of inhibitors of prostaglandin synthesis.

    PubMed

    Hofer, M; Pospísil, M; Tkadlecek, L; Viklická, S; Pipalová, I; Holá, J

    1992-01-01

    An impairment of the survival of mice subjected to whole-body gamma-irradiation with a lethal dose of 10 Gy and treated with a repeated postirradiation administration of prostaglandin synthesis inhibitors (PGSIs), indomethacin or diclofenac, was observed. Morphological examination of the gastrointestinal tract and the estimation of blood loss into its lumen in animals treated with diclofenac did not show serious damage such as haemorrhages or perforation, but revealed structural injury to the intestinal mucosa indicating inflammatory processes. The lesions found are supposed to be connected with increased intestinal permeability which leads to endotoxin escape from the gut and a subsequent increased mortality rate of irradiated animals. It may be concluded that PGSIs are not suitable for the management of radiation sickness after an exposure to lethal doses of ionizing radiation.

  17. Effect of gamma-irradiation on the lipid profile of nutmeg (Myristica fragrans Houtt.).

    PubMed

    Niyas, Zareena; Variyar, Prasad S; Gholap, Achyut S; Sharma, Arun

    2003-10-22

    The effect of gamma-irradiation on the lipid constituents of nutmeg (Myristica fragrans) was examined at radiation doses between 2.5 and 10 kGy. The fatty acid composition of the triacylglycerol, the major lipid component, was found to be made up of myristic (90%), palmitic (6%), lauric (3%), petroselinic (0.13%), and stearic acids (0.5%) as determined by gas chromatography-mass spectrometry. A dose-dependent decrease in the triacylglycerol content and a concomitant increase in free fatty acids characterized the lipid profile of the irradiated spice. This suggested a breakdown of acylglycerols during radiation processing, resulting in the release of free fatty acids. These changes were found to be significant at doses above 5 kGy. The impact of the above changes on the flavor of the spice is discussed. These studies suggest that radiation processing of nutmeg should be limited to a dose of 5 kGy.

  18. Behavior of optical thin-film materials and coatings under proton and gamma irradiation.

    PubMed

    Di Sarcina, Ilaria; Grilli, Maria Luisa; Menchini, Francesca; Piegari, Angela; Scaglione, Salvatore; Sytchkova, Anna; Zola, Danilo

    2014-02-01

    Optical materials and coatings are exposed to the flux of energetic particles when used in either space applications or nuclear energy plants. The study of their behavior in such an environment is important to avoid failure of the optical components during their operation. The optical performance of several thin-film materials ((HfO2, Ta2O5, Nb2O5, TiO2, SiO2) and coatings, under irradiation with high-dose gamma rays (5.8 MGy) and exposure to low-energy (60 keV) protons, has been investigated. Some variations of optical properties have been detected in silicon oxide after irradiation, while the other materials are stable in such conditions.

  19. Breeding erect plant type sweetpotato lines using cross breeding and gamma-ray irradiation.

    PubMed

    Kuranouchi, Toshikazu; Kumazaki, Tadashi; Kumagai, Toru; Nakatani, Makoto

    2016-06-01

    Few sweetpotato (Ipomoea batatas Lam.) cultivars with erect plant type are available despite their advantages over spreading type, such as simplicity of cultivation and ability to adapt to limited space. One of the reasons is insufficiency of their agronomic characteristics for table use. So, it is important to overcome these drawbacks of ER-type lines. We attempted to breed new erect plant type sweetpotato lines having good agronomic traits using cross breeding and mutation breeding with gamma-ray irradiation. With cross breeding we successfully developed new erect plant type lines with almost equal levels of yield as compared to 'Beniazuma', one of the leading cultivars in Japan. However, mutation breeding failed to develop any promising lines because we could not obtain distinct erect plant type lines. In the future larger numbers of plants should be used for mutation breeding, and irradiation methods should be improved. PMID:27436957

  20. Effects of gamma irradiation on the shoot length of Cicer seeds [rapid communication

    NASA Astrophysics Data System (ADS)

    Toker, Cengiz; Uzun, Bulent; Canci, Huseyin; Oncu Ceylan, F.

    2005-08-01

    The effects of radiation on the shoot and root lengths of germinated seedling of irradiated seeds of Cicer species, i.e. three kabuli types and four desi types of cultivated chickpea ( Cicer arietinum Ladiz.) and 2 annual wild types ( C. reticulatum Ladiz. and C. bijugum K.H. Rech.) were investigated. The seeds were irradiated with a 60Co gamma source using 0, 200, 300 and 400 Gy doses at 1.66 kGy h -1. At 200 Gy minor effects could be observed, but at 400 Gy an obvious depression of shoot length was observed. The kabuli types were more affected than the desi ones. The critical dose that prevented the shoot and root elongation varied among species and also ranged from genotypes to genotype within species.

  1. Lymphoid cell kinetics under continuous low dose-rate gamma irradiation: A comparison study

    NASA Technical Reports Server (NTRS)

    Foster, B. R.

    1975-01-01

    A comparison study was conducted of the effects of continuous low dose-rate gamma irradiation on cell population kinetics of lymphoid tissue (white pulp) of the mouse spleen with findings as they relate to the mouse thymus. Experimental techniques employed included autoradiography and specific labeling with tritiated thymidine (TdR-(h-3)). The problem studied involved the mechanism of cell proliferation of lymphoid tissue of the mouse spleen and thymus under the stress of continuous irradiation at a dose rate of 10 roentgens (R) per day for 105 days (15 weeks). The aim was to determine whether or not a steady state or near-steady state of cell population could be established for this period of time, and what compensatory mechanisms of cell population were involved.

  2. Gamma irradiation assisted fungal degradation of the polypropylene/biomass composites

    NASA Astrophysics Data System (ADS)

    Butnaru, Elena; Darie-Niţă, Raluca Nicoleta; Zaharescu, Traian; Balaeş, Tiberius; Tănase, Cătălin; Hitruc, Gabriela; Doroftei, Florica; Vasile, Cornelia

    2016-08-01

    White-rot fungus Bjerkandera adusta has been tested for its ability to degrade some biocomposites materials based on polypropylene and biomass (Eucalyptus globulus, pine cones, and Brassica rapa). γ-irradiation was applied to initiate the degradation of relatively inert polypropylene matrix. The degradation process has been studied by scanning electron microscopy, atomic force microscopy, infrared spectroscopy, contact angle measurements, rheological and chemiluminescence tests. These analyses showed that the polypropylene/biomass composites properties are worsen under the action of the selected microorganism. The formation of cracks and scrap particles over the entire matrix surface and the decrease of the complex viscosity values, as well as the dynamic moduli of gamma irradiated PP/biomass composite and exposed to Bjerkandera adusta fungus, indicate fungal efficiency in composite degradation.

  3. Ten year experience in operation of a sewage sludge treatment plant using gamma irradiation

    NASA Astrophysics Data System (ADS)

    Lessel, T.; Suess, A.

    The first sewage sludge gamma irradiation plant in a technical scale, using Co-60 has been successfully working in Geiselbullach near Munich, FRG, since July 1973. More than 250,000 m 3 of liquid sludge has been disinfected during that time. A very simple plant design, a fully automatical operation during 24 hours and a high availability proved the practical applicability of such a facility in a sewage water purification plant without any specially silled personnel. Beside wide investigations for hygienic aspects, changing of the physical sludge characteristics, effect of irradiated sludge on soil and plants the economic considerations were regarded as important. Experiments werde undertaken to optimize the flexibility of the plant operation and to reduce the necessary radiation dose for minimizing the operation costs.

  4. Facile Synthesis of Silver Nanoparticles Under {gamma}-Irradiation: Effect of Chitosan Concentration

    SciTech Connect

    Huang, N. M.; Radiman, S.; Ahmad, A.; Idris, H.; Lim, H. N.; Khiew, P. S.; Chiu, W. S.; Tan, T. K.

    2009-06-01

    In the present study, a biopolymer, low molecular weight chitosan had been utilized as a 'green' stabilizing agent for the synthesis of silver nanoparticles under {gamma}-irradiation. The as-synthesized silver nanoparticles have particle diameters in the range of 5 nm-30 nm depending on the percentage of chitosan used (0.1 wt%, 0.5 wt%, 1.0 wt% and 2.0 wt%). It was found that the yield of the silver nanoparticles was in accordance with the concentration of chitosan presence in the solution due to the reduction by the chitosan radical during irradiation. The highly stable chitosan encapsulated silver nanoparticles were characterized using transmission electron microscopy (TEM), UV-Visible spectrophotometer (UV-VIS) and X-ray diffraction spectroscopy (XRD)

  5. EPR study of gamma irradiated DL-methionine sulfone single crystals

    NASA Astrophysics Data System (ADS)

    Karabulut, Bünyamin; Yıldırım, İlkay

    2015-12-01

    Electron paramagnetic resonance (EPR) study of gamma irradiated dl-2-amino-4-(Methylsulfonyl) butyric acid (dl-methionine sulfone, hereafter dl-ABA) single crystals and powder was performed at room temperature. It has been found that this compound indicates the existence of C. O2- and N. H2 radicals after γ-irradiation. While g and hyperfine splitting values for the N. H2 radical were observed, for the C. O2- radical, only the g factor was measured. The EPR spectra have shown that N. H2 radical has two groups each having two distinct sites and C. O2- radical has one site. The principal g and hyperfine values for all sites were analyzed.

  6. Breeding erect plant type sweetpotato lines using cross breeding and gamma-ray irradiation

    PubMed Central

    Kuranouchi, Toshikazu; Kumazaki, Tadashi; Kumagai, Toru; Nakatani, Makoto

    2016-01-01

    Few sweetpotato (Ipomoea batatas Lam.) cultivars with erect plant type are available despite their advantages over spreading type, such as simplicity of cultivation and ability to adapt to limited space. One of the reasons is insufficiency of their agronomic characteristics for table use. So, it is important to overcome these drawbacks of ER-type lines. We attempted to breed new erect plant type sweetpotato lines having good agronomic traits using cross breeding and mutation breeding with gamma-ray irradiation. With cross breeding we successfully developed new erect plant type lines with almost equal levels of yield as compared to ‘Beniazuma’, one of the leading cultivars in Japan. However, mutation breeding failed to develop any promising lines because we could not obtain distinct erect plant type lines. In the future larger numbers of plants should be used for mutation breeding, and irradiation methods should be improved. PMID:27436957

  7. Polymerization of SDS-PAGE gel by gamma irradiation and its use for characterization by electrophoresis of a protein [rapid communication

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Ho; Kim, Jin-Hee; Seo, Ji-Hyun; Lee, Ju-Woon; Lim, Sang-Yong; Lee, Ho-Joon; Byun, Myung-Woo

    2005-12-01

    An SDS-PAGE gel strip was polymerized using a gamma irradiation process and used for electrophoresis. The relative mobility (Rf) and resolution of marker proteins were determined. Polymerization was induced by gamma irradiation in an acrylamide and N'-methylene bisacrylamide mixture with and without the polymerization initiators, ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED). The calibration curves of log 10 molecular weight of the protein versus the distance of the migration showed higher correlations in the gamma irradiated gel than in that of the APS-TEMED polymerized control. The Rf value of the protein was increased in the gel polymerized by gamma-irradiation.

  8. Fatty acid profile of gamma-irradiated and cooked African oil bean seed (Pentaclethra macrophylla Benth)

    PubMed Central

    Olotu, Ifeoluwa; Enujiugha, Victor; Obadina, Adewale; Owolabi, Kikelomo

    2014-01-01

    The safety and shelf-life of food products can be, respectively, ensured and extended with important food-processing technologies such as irradiation. The joint effect of cooking and 10 kGy gamma irradiation on the fatty acid composition of the oil of Pentaclethra macrophylla Benth was evaluated. Oils from the raw seed, cooked seeds, irradiated seeds (10 kGy), cooked, and irradiated seeds (10 kGy) were extracted and analyzed for their fatty acid content. An omega-6-fatty acid (linoleic acid) was the principal unsaturated fatty acid in the bean seed oil (24.6%). Cooking significantly (P < 0.05) increased Erucic acid by 3.3% and Linolenic acid by 23.0%. Combined treatment significantly (P < 0.05) increased C18:2, C6:0, C20:2, C18:3, C20:3, C24:0, and C22:6 being linoleic, caproic, eicosadienoic, linolenic, eicosatrienoic, ligoceric, and docosahexaenoic acid, respectively, and this increase made the oil sample to have the highest total fatty acid content (154.9%), unsaturated to saturated fatty acid ratio (109.6), and unsaturated fatty acid content (153.9%). 10 kGy irradiation induces the formation of C20:5 (eicosapentaenoic), while cooking induced the formation of C20:4 (arachidic acid), C22:6 (Heneicosanoic acid), and C22:2 (docosadienoic acid). Combined 10 kGy cooking and irradiation increased the susceptibility of the oil of the African oil bean to rancidity. PMID:25493197

  9. Fatty acid profile of gamma-irradiated and cooked African oil bean seed (Pentaclethra macrophylla Benth).

    PubMed

    Olotu, Ifeoluwa; Enujiugha, Victor; Obadina, Adewale; Owolabi, Kikelomo

    2014-11-01

    The safety and shelf-life of food products can be, respectively, ensured and extended with important food-processing technologies such as irradiation. The joint effect of cooking and 10 kGy gamma irradiation on the fatty acid composition of the oil of Pentaclethra macrophylla Benth was evaluated. Oils from the raw seed, cooked seeds, irradiated seeds (10 kGy), cooked, and irradiated seeds (10 kGy) were extracted and analyzed for their fatty acid content. An omega-6-fatty acid (linoleic acid) was the principal unsaturated fatty acid in the bean seed oil (24.6%). Cooking significantly (P < 0.05) increased Erucic acid by 3.3% and Linolenic acid by 23.0%. Combined treatment significantly (P < 0.05) increased C18:2, C6:0, C20:2, C18:3, C20:3, C24:0, and C22:6 being linoleic, caproic, eicosadienoic, linolenic, eicosatrienoic, ligoceric, and docosahexaenoic acid, respectively, and this increase made the oil sample to have the highest total fatty acid content (154.9%), unsaturated to saturated fatty acid ratio (109.6), and unsaturated fatty acid content (153.9%). 10 kGy irradiation induces the formation of C20:5 (eicosapentaenoic), while cooking induced the formation of C20:4 (arachidic acid), C22:6 (Heneicosanoic acid), and C22:2 (docosadienoic acid). Combined 10 kGy cooking and irradiation increased the susceptibility of the oil of the African oil bean to rancidity.

  10. Reduction of ochratoxin A in dry-cured meat products using gamma-irradiation.

    PubMed

    Domijan, Ana-Marija; Pleadin, Jelka; Mihaljević, Branka; Vahčić, Nada; Frece, Jadranka; Markov, Ksenija

    2015-01-01

    This study investigated the efficiency of gamma (γ)-irradiation in the reduction of ochratoxin A (OTA) present in dry-cured meat products prepared from intentionally contaminated raw materials from OTA-treated pigs. OTA concentrations determined in the samples (n = 24) ranged from 25.8 μg kg(-1) in bacon to 17.8 μg kg(-1) in smoked ham. After γ-irradiation at doses of 3, 7 and 10 kGy (i.e. the doses used in the food industry), a dose-depended OTA reduction was observed; however, it was not statistically significant. The mean OTA reduction achieved with 3-, 7- and 10-kGy γ-doses was approximated to 8.5%, 13.9% and 22.5%, respectively. The storage of irradiated samples (1 month, 4°C) did not significantly affect OTA levels. Based on the correlation between the OTA reduction level and basic chemical composition of dry-cured meat samples, OTA reduction may be linked to the samples' fat content. The results indicate that γ-irradiation can reduce OTA levels in dry-cured meat products, but only to a limited extent due to the complexity of the matrix.

  11. Whole-Genome Sequencing in Microbial Forensic Analysis of Gamma-Irradiated Microbial Materials

    PubMed Central

    Broomall, Stacey M.; Ait Ichou, Mohamed; Krepps, Michael D.; Johnsky, Lauren A.; Karavis, Mark A.; Hubbard, Kyle S.; Insalaco, Joseph M.; Betters, Janet L.; Redmond, Brady W.; Rivers, Bryan A.; Liem, Alvin T.; Hill, Jessica M.; Fochler, Edward T.; Roth, Pierce A.; Rosenzweig, C. Nicole; Skowronski, Evan W.

    2015-01-01

    Effective microbial forensic analysis of materials used in a potential biological attack requires robust methods of morphological and genetic characterization of the attack materials in order to enable the attribution of the materials to potential sources and to exclude other potential sources. The genetic homogeneity and potential intersample variability of many of the category A to C bioterrorism agents offer a particular challenge to the generation of attributive signatures, potentially requiring whole-genome or proteomic approaches to be utilized. Currently, irradiation of mail is standard practice at several government facilities judged to be at particularly high risk. Thus, initial forensic signatures would need to be recovered from inactivated (nonviable) material. In the study described in this report, we determined the effects of high-dose gamma irradiation on forensic markers of bacterial biothreat agent surrogate organisms with a particular emphasis on the suitability of genomic DNA (gDNA) recovered from such sources as a template for whole-genome analysis. While irradiation of spores and vegetative cells affected the retention of Gram and spore stains and sheared gDNA into small fragments, we found that irradiated material could be utilized to generate accurate whole-genome sequence data on the Illumina and Roche 454 sequencing platforms. PMID:26567301

  12. Effect of gamma irradiation on transport of charge carriers in Cu nanowires

    NASA Astrophysics Data System (ADS)

    Gehlawat, Devender; Chauhan, R. P.; Sonkawade, R. G.; Chakarvarti, S. K.

    2012-01-01

    In this paper, we report the effect of gamma ray photons on the electrical conductivity of 100 nm Cu nanowires prepared by the technique of electrodeposition using track-etched membranes. Different fluences of photons have been used to observe the effect and in each case of post-irradiation, electrical conductivity is found to increase in a linear manner with increase in applied potential difference; however the rate of increase of conductivity is different in different cases of radiation fluence. Grain boundary scattering is of significance for the post-irradiation parabolic nature of the I-V characteristics (IVC), which are of a linear pattern following Ohm's law before irradiation. Increase or decrease in the number of charge carriers during their transport through the nanowires is the result of two competitive processes—specular and diffusive scattering of charge carriers (electrons) from grain boundaries, which are itself a region of high resistance rather than inter-grain regions. The results have been discussed in light of the Mayadas and Shatzkes (MS) model with a slight modification for irradiated nanowires.

  13. Effect of gamma irradiation at intermediate doses on the performance of reverse osmosis membranes

    NASA Astrophysics Data System (ADS)

    Combernoux, Nicolas; Labed, Véronique; Schrive, Luc; Wyart, Yvan; Carretier, Emilie; Moulin, Philippe

    2016-07-01

    The goal of this study is to explain the degradation of Polyamide (PA) composite reverse osmosis membrane (RO) in function of the irradiation dose. Irradiations were performed with a gamma 60Co source in wet conditions and under oxygen atmosphere. For different doses of 0.2 and 0.5 MGy with a constant dose rate of 0.5 kGy h-1, RO membranes performances (NaCl retention, permeability) were studied before and after irradiation. ATR-FTIR, ion chromatography and gas chromatography were used to characterize structural modification. Results showed that the permeability of RO membranes irradiated at 0.2 MGy exhibited a small decrease, related to scissions of the PVA coating. However, retention did not change at this dose. At 0.5 MGy, permeability showed a large increase of a factor around 2 and retention began to decrease from 99% to 95%. Chromatography measurements revealed a strong link between permselectivity properties variation, ion leakage and oxygen consumption. Add to ATR-FTIR observations, these results emphasized that the cleavages of amide and ester bonds were observed at 0.5 MGy, more precisely the loss of hydrogen bonds between polyamide chains. By different analysis, modifications of the polysulfone layer occur until a dose of 0.2 MGy.

  14. Comparative effects of gamma irradiation and phosphine fumigation on the quality of white ginseng

    NASA Astrophysics Data System (ADS)

    Kwon, J.-H. J.-H.; Byun, M.-W. M.-W.; Kim, K.-S. K.-S.; Kang, I.-J. I.-J.

    2000-03-01

    The hygienic, physicochemical, and organoleptic qualities of white ginseng were monitored during 6 months under accelerated conditions (40°C, 90% r.h.) by observing its microbial populations, disinfestation, and some quality attributes following either gamma irradiation at 2.5-10 kGy or commercial phosphine (PH 3) fumigation. In a comparative study, both treatments were found to be effective for disinfecting the stored samples. Phosphine showed no appreciable decontaminating effects on microorganisms contaminated including coliforms, while 5 kGy irradiation was sufficient to control all microorganisms related to the quality of the packed samples. Irradiation at 5 kGy caused negligible changes in physicochemical attributes of the samples, such as ginsenosides, amino acids, fatty acids, and organoleptic properties, whereas phosphine fumigation was found detrimental to sensory flavor ( P<0.01). Quality deterioration occurred in the commercially-packed samples was in the following order: the control, 10 kGy-, phosphine-, and 2.5-5 kGy-treated samples. Accordingly, irradiation at <5 kGy was found to be an effective alternative to phosphine fumigation for white ginseng.

  15. Effect of gamma irradiation on microbial decontamination, and chemical and sensory characteristic of lycium fruit

    NASA Astrophysics Data System (ADS)

    Wen, Hsiao-Wei; Chung, Hsiao-Ping; Chou, Fong-In; Lin, I.-hsin; Hsieh, Po-Chow

    2006-05-01

    Lycium fruit, popular traditional Chinese medicine and food supplement generally is ingested uncooked, was exposed to several doses of gamma irradiation (0-14 kGy) to evaluate decontamination efficiency, changes in chemical composition, and changes in sensory characteristic. In this study, lycium fruit specimens contained microbial counts of 3.1×10 3-1.7×10 5 CFU/g and 14 kGy was sufficient for microbial decontamination. Before irradiation, the main microbe isolated from lycium fruit was identified as a strain of yeast, Cryptococcus laurentii. After 10 kGy of irradiation, a Gram-positive spore-forming bacterium, Bacillus cereus, was the only survivor. The first 90% reduction (LD 90) of C. laurentii and B. cereus was approximately 0.6 and 6.5 kGy, respectively, the D 10 doses of C. laurentii and B. cereus was approximately 0.6 and 1.7 kGy, respectively. After 14 kGy irradiation, except the vitamin C content, other chemical composition (e.g., crude protein, β-carotene, riboflavin, fructose, etc.) and the sensory characteristic of lycium fruit specimens did not have significant changes. In conclusion, 14 kGy is the optimal decontamination dose for lycium fruit for retention of its sensory quality and extension of shelf life.

  16. Thermoluminescence Response of Gamma Irradiated SrAl2O4:Eu2+/Dy3+ Nanophosphor

    NASA Astrophysics Data System (ADS)

    Bedyal, A. K.; Kumar, Vinay; Lochab, S. P.; Singh, Fouran; Ntwaeaborwa, O. M.; Swart, H. C.

    In this paper, we report on the thermoluminescence response of nanocrystalline co-doped alkaline earth aluminates synthesized by combustion method using metal nitrate as precursor and urea as fuel. A broad TL glow peak was observed at 367 K with a shoulder at 400K. TL Anal program has been used for GCD curve fitting. The Kinetic parameters like, the activation energy (Eα), the frequency factor (s) and the order of kinetics were calculated for the SrAl2O4: Eu2+, Dy3+nanophosphors. The best dopants combination was Eu (1 mol%) and Dy (2 mol%). The samples were irradiated with γ-dose in the range 20Gy-800Gy, at room temperature. A shift from 367 K to 376 K was also observed in the main peak with an increase in irradiation dose which suggest that the irradiation doses affect the distributions of traps produced by the gamma-ray irradiations. Kinetic parameters also suggest that TL glow curve in SrAl2O4: Eu2+, Dy3+ nanophosphors is obeying second order kinetics. The nanophosphors show linear response with dose.

  17. The effects of gamma irradiation on the vitamin E content and sensory qualities of pecan nuts ( Carya illinoensis)

    NASA Astrophysics Data System (ADS)

    Taipina, Magda S.; Lamardo, Leda C. A.; Rodas, Maria A. B.; del Mastro, Nelida L.

    2009-07-01

    Pecan nuts ( Carya illinoensis) were treated with gamma irradiation and evaluated for changes in vitamin E content and sensory properties. Irradiation at 1 and 3 kGy resulted in no changes in vitamin E content measured as α-tocopherol equivalents by a colorimetric method. A trained sensory panel found that irradiation at 1 kGy produced no significant changes in appearance, aroma, texture and flavor attributes. The vitamin E content of irradiated pecan nuts remained stable, but from the point of view of sensory quality a dose of merely 1 kGy can be considered as recommendable.

  18. Impact of gamma-irradiation on the properties of n-type AlGaN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Flitsiyan, Elena; Chernyak, Leonid

    2013-03-01

    Gamma-photon irradiation of AlGaN/GaN HEMTs with the modest dose of 700 Gy* resulted in significant deterioration of their DC characteristics. To understand the nature of the observed effect, we carried out a series of variable temperature EBIC measurements in the vicinity of HEMT's gate in-situ in Scanning Electron Microscope. The measurements were performed on 3 different devices, which were exposed to various gamma-irradiation doses. Temperature dependent EBIC measurements allowed obtaining activation energies for levels in the material's forbidden gap, which are responsible for carrier recombination. While the diffusion length decreases significantly with increasing irradiation dose, the activation energy, associated with carrier recombination, gets larger. This fact indicates generation of new deep levels caused by gamma-photon irradiation. These levels act as traps for electrons in AlGaN/GaN HEMT channel, thus reducing the drain current and leading to degradation of other device characteristics. The investigated effects of gamma irradiation are likely related to, epitaxial layer quality and composition. Therefore, the study of materials with variations in these properties is necessary to fully understand the irradiation-induced mechanisms.

  19. Changes in antigenicity of porcine serum albumin in gamma-irradiated sausage extract by treatment with pepsin and trypsin

    NASA Astrophysics Data System (ADS)

    Kim, Koth-Bong-Woo-Ri; Song, Eu-Jin; Lee, So-Young; Park, Jin-Gyu; Lee, Ju-Woon; Byun, Myung-Woo; Ahn, Dong-Hyun

    2011-11-01

    Pork is known as an allergenic food with porcine serum albumin (PSA, 66 kDa) representing the major allergen. This study was conducted to investigate the change in antigenicity of PSA in gamma-irradiated sausage extract treated with pepsin and trypsin. Sausage products (A and B) were irradiated at 1, 3, 10, and 20 kGy. After irradiation, sausage proteins were extracted and digested with pepsin (1:200, 30 min) and trypsin (1:300, 5, 30, 60, 90, and 120 min). The binding ability of PSA in extracts of the irradiated sausages (A and B) decreased by over 3 kGy relative to the binding ability of PSA in extracts of intact sausages and showed no notable differences when the dose of radiation ranged from 3 to 20 kGy. After treatment with pepsin and trypsin, the binding ability of PSA in extracts of the irradiated sausages was decreased more relative to that of intact sausages and showed no significant differences when the period of trypsin treatment is increased or when the dose of irradiation is increased. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results indicated that there was no visible change in the intensity of the PSA band in extracts of the irradiated sausages. After pepsin and trypsin treatment, the intensity of PSA band faded with increasing doses of irradiation. In conclusion, antigenicity of PSA in pork sausages could be reduced by gamma irradiation.

  20. Gamma irradiation of sorghum flour: Effects on microbial inactivation, amylase activity, fermentability, viscosity and starch granule structure

    NASA Astrophysics Data System (ADS)

    Mukisa, Ivan M.; Muyanja, Charles M. B. K.; Byaruhanga, Yusuf B.; Schüller, Reidar B.; Langsrud, Thor; Narvhus, Judith A.

    2012-03-01

    Malted and un-malted sorghum ( Sorghum bicolor (L.) Moench) flour was gamma irradiated with a dose of 10 kGy and then re-irradiated with 25 kGy. The effects of irradiation on microbial decontamination, amylase activity, fermentability (using an amylolytic L. plantarum MNC 21 strain), starch granule structure and viscosity were determined. Standard methods were used during determinations. The 10 kGy dose had no effect on microbial load of un-malted flour but reduced that of malted flour by 3 log cycles. Re-irradiation resulted in complete decontamination. Irradiation of malt caused a significant ( p<0.05) reduction in alpha and beta amylase activity (22% and 32%, respectively). Irradiation of un-malted flour increased the rates of utilization of glucose and maltose by 53% and 100%, respectively, during fermentation. However, microbial growth, rate of lactic acid production, final lactic acid concentration and pH were not affected. Starch granules appeared normal externally even after re-irradiation, however, granules ruptured and dissolved easily after hydration and gelatinization. Production of high dry matter density porridge (200 g dry matter/L) with a viscosity of 3500 cP was achieved by irradiation of un-malted flout at 10 kGy. Gamma irradiation can be used to decontaminate flours and could be utilized to produce weaning porridge from sorghum.

  1. The effect of fast neutron and gamma irradiation on thermal, structural and colorant properties of 2,6-diaminopyridine.

    PubMed

    Mohammadi, Hassangholi; Hassanzadeh, Ali; Khodabakhsh, Rasol

    2010-10-01

    The variation in structural, thermal and colorant properties of 2,6-diaminopyridine were studied using differential scanning calorimetry (DSC), UV-visible, NMR spectroscopies and powder X-ray diffraction techniques, before and after fast neutrons irradiation with 2.12 and 3.50 kGy and gamma irradiation with 136.16 Gy doses. Under fast neutron irradiation, the sample enthalpy values, and melting and boiling temperatures were varied with increase in the irradiation dose. But the variation in boiling temperature was more pronounced than that of the melting point. However, there was no drastic change in these transition temperatures. The kinetic parameters were calculated using free isoconversional and Kissinger analysis methods. Moreover, UV-visible spectra showed that fast neutron and gamma irradiations had destroyed the color of the title compound. The gamma irradiation showed similar effect on structural and thermal properties. Results are also shown where the intensity of XRD patterns strongly depends on the irradiation dose. According to the NMR results, it seems that the collision occurs between para-hydrogen of 2,6-DAP and fast neutrons.

  2. Effect of annealing on electronic carrier transport properties of gamma-irradiated AlGaN/GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Yadav, Anupama; Schwarz, Casey; Shatkhin, Max; Wang, Luther; Flitsiyan, Elena; Chernyak, Leonid; Liu, Lu; Hwang, Ya; Ren, Fan; Pearton, Stephen; Department of Physics, University of Central Florida Collaboration; Department of Chemical Engineering, University of Florida Collaboration; Department of Materials Science; Engineering, University of Florida Collaboration

    2014-03-01

    AlGaN/GaN High Electron Mobility Transistors were irradiated with 60Co gamma-ray doses from 100Gy to 1000Gy, in order to analyze the effects of irradiation on the devices' transport properties. Temperature dependent Electron Beam Induced Current (EBIC) measurements, conducted on the devices before and after exposure to gamma-irradiation, allowed for the obtaining of activation energy related to radiation-induced defects due to nitrogen vacancies. Later, the devices were annealed at 200o C for 25 minutes. All the measurements were performed again to study the effect of annealing on the gamma-irradiated devices. Annealing of gamma-irradiated transistors shows that partial recovery of device performance is possible at this temperature. DC current-voltage measurements were also conducted on the transistors to assess the impact of gamma-irradiation and annealing on transfer, gate and drain characteristics.

  3. Effect of gamma irradiation on hyaluronic acid and dipalmitoylphosphatidylcholine (DPPC) interaction

    SciTech Connect

    Ahmad, Ainee Fatimah; Mohd, Hur Munawar Kabir; Taqiyuddin Mawardi bin Ayob, Muhammad; Rosli, Nur Ratasha Alia Md; Mohamed, Faizal; Radiman, Shahidan; Rahman, Irman Abdul

    2014-09-03

    DPPC lipids are the major component constituting the biological membrane, and their importances in various physiological functions are well documented. Hyaluronic acid (HA) in the synovial joint fluid functions as a lubricant, shock absorber and a nutrient carrier. Gamma irradiation has also been found to be effective in depolymerizing and cleaving molecular chains related to free radicals, thus extends with changes in chemical composition as well as its physiological functions. This research are conducted to investigate the hyaluronic acid (HA) and 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) interaction in form of vesicles and its effect to gamma radiation. The size of DPPC vesicles formed via gentle hydration method is between 100 to 200 nm in diameter. HA (0.1, 0.5 and 1.0 mg/ml) was added into the vesicles and characterized by using TEM to determine vesicle size distributions, fusion and rupture of DPPC structure. The results demonstrated that the size of the vesicles approximately between 200 to 300 nm which caused by vesicles fusion with HA and formed even larger vesicles. After being irradiated by 0 to 200 Gy, the size of vesicles decreased as HA was degraded. To elucidate the mechanism of these effects, FTIR spectra were carried out and have shown that at absorption bands at 1700–1750 cm{sup −1} due to formation of carboxylic acid and leads to alteration of HA structure.

  4. Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers

    NASA Astrophysics Data System (ADS)

    Van Phu, Dang; Quoc, Le Anh; Duy, Nguyen Ngoc; Lan, Nguyen Thi Kim; Du, Bui Duy; Luan, Le Quang; Hien, Nguyen Quoc

    2014-04-01

    Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli ( E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

  5. Antioxidant Capacities and Total Phenolic Contents Enhancement with Acute Gamma Irradiation in Curcuma alismatifolia (Zingiberaceae) Leaves

    PubMed Central

    Taheri, Sima; Abdullah, Thohirah Lee; Karimi, Ehsan; Oskoueian, Ehsan; Ebrahimi, Mahdi

    2014-01-01

    The present study was conducted in order to assess the effect of various doses of acute gamma irradiation (0, 10, 15, and 20 Gy) on the improvement of bioactive compounds and their antioxidant properties of Curcuma alismatifolia var. Sweet pink. The high performance liquid chromatography (HPLC) and gas chromatography (GC) analysis uncovered that various types of phenolic, flavonoid compounds, and fatty acids gradually altered in response to radiation doses. On the other hand, antioxidant activities determined by 1,1-Diphenyl-2-picryl-hydrazyl (DPPH), ferric reduction, antioxidant power (FRAP), and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay showed a higher irradiation level significantly increased the antioxidant properties. This study revealed an efficient effect of varying levels of gamma radiation, based on the pharmaceutical demand to enhance the accumulation and distribution of bioactive compounds such as phenolic and flavonoid compounds, fatty acids, as well as their antioxidant activities in the leaves of C. alismatifolia var. Sweet pink. PMID:25056545

  6. EPR Investigation of Gamma-Irradiated Rapana Thomasiana (Gastropoda, Muricidae) Shell

    SciTech Connect

    Seletchi, Emilia Dana; Duliu, Octavian G.; Georgescu, Rodica

    2007-04-23

    The shell of Rapana Thomasiana snail, a carnivorous gastropod collected from the coasts of the Black Sea (Romania) was investigated by using Electron Paramagnetic Resonance (EPR) spectroscopy. The samples in powder form were irradiated with a 60Co gamma-ray source at ambient temperature in the dose range between 1.06 and 11.3 kGy. The measurements showed that the EPR signal intensity enhanced following saturation exponential with the absorbed dose. The estimated EPR parameters: g1 = 1.9976, g2 = 2.0006, g3 = 2.0015, g4 = 2.0030 and g5 = 2.0043 revealed a complex spectrum consisting of CO{sub 2}{sup -}, CO{sub 3}{sup 3-} and CO{sub 3}{sup -} species. A very weak signal at g6 = 2.0057 was associated to SO{sub 2}{sup -} electron center. All EPR signals of gamma-irradiated samples decreased with various rate with the of 100 deg. C isothermal annealing time.

  7. The effects of gamma irradiation on diclofenac sodium, liposome and niosome ingredients for rheumatoid arthritis

    PubMed Central

    Turker, Selcan; Çolak, Seyda; Korkmaz, Mustafa; Kiliç, Ekrem; Özalp, Meral

    2013-01-01

    The use of gamma rays for the sterilization of pharmaceutical raw materials and dosage forms is an alternative method for sterilization. However, one of the major problems of the radiosterilization is the production of new radiolytic products during the irradiation process. Therefore, the principal problem in radiosterilization is to determine and to characterize these physical and chemical changes originating from high-energy radiation. Parenteral drug delivery systems were prepared and in vitro characterization, biodistribution and treatment studies were done in our previous studies. Drug delivery systems (liposomes, niosomes, lipogelosomes and niogelosomes) encapsulating diclofenac sodium (DFNa) were prepared for the treatment of rheumatoid arthritis (RA). This work complies information about the studies developed in order to find out if gamma radiation could be applied as a sterilization method to DFNa, and the raw materials as dimyristoyl phosphatidylcholine (DMPC), surfactant I [polyglyceryl-3-cethyl ether (SUR I)], dicethyl phosphate (DCP) and cholesterol (CHOL) that are used to prepare those systems. The raw materials were irradiated with different radiation doses (5, 10, 25 and 50 kGy) and physicochemical changes (organoleptic properties pH, UV and melting point), microbiological evaluation [sterility assurance level (SAL), sterility and pyrogen test] and electron spin resonance (ESR) characteristics were studied at normal (25 °C, 60% relative humidity) and accelerated (40 °C, 75% relative humidity) stability test conditions. PMID:24265902

  8. Effect of gamma irradiation on hyaluronic acid and dipalmitoylphosphatidylcholine (DPPC) interaction

    NASA Astrophysics Data System (ADS)

    Ahmad, Ainee Fatimah; Mohd, Hur Munawar Kabir; bin Ayob, Muhammad Taqiyuddin Mawardi; Rosli, Nur Ratasha Alia Md; Mohamed, Faizal; Radiman, Shahidan; Rahman, Irman Abdul

    2014-09-01

    DPPC lipids are the major component constituting the biological membrane, and their importances in various physiological functions are well documented. Hyaluronic acid (HA) in the synovial joint fluid functions as a lubricant, shock absorber and a nutrient carrier. Gamma irradiation has also been found to be effective in depolymerizing and cleaving molecular chains related to free radicals, thus extends with changes in chemical composition as well as its physiological functions. This research are conducted to investigate the hyaluronic acid (HA) and 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) interaction in form of vesicles and its effect to gamma radiation. The size of DPPC vesicles formed via gentle hydration method is between 100 to 200 nm in diameter. HA (0.1, 0.5 and 1.0 mg/ml) was added into the vesicles and characterized by using TEM to determine vesicle size distributions, fusion and rupture of DPPC structure. The results demonstrated that the size of the vesicles approximately between 200 to 300 nm which caused by vesicles fusion with HA and formed even larger vesicles. After being irradiated by 0 to 200 Gy, the size of vesicles decreased as HA was degraded. To elucidate the mechanism of these effects, FTIR spectra were carried out and have shown that at absorption bands at 1700-1750 cm-1 due to formation of carboxylic acid and leads to alteration of HA structure.

  9. Removal of compounds used as plasticizers and herbicides from water by means of gamma irradiation.

    PubMed

    Rivera-Utrilla, José; Daiem, Mahmoud M Abdel; Sánchez-Polo, Manuel; Ocampo-Pérez, Raúl; López-Peñalver, Jesús J; Velo-Gala, Inmaculada; Mota, Antonio J

    2016-11-01

    Gamma radiation has been used to induce the degradation of compounds used as plasticizers and herbicides such as phthalic acid (PA), bisphenol A (BPA), diphenolic acid (DPA), 2,4-dichlorophenoxy-acetic acid (2,4-D), and 4-chloro-2-methylphenoxyacetic acid (MCPA) in aqueous solution, determining the dose constants, removal percentages, and radiation-chemical yields. The reaction rate constants of hydroxyl radical (HO), hydrated electron (eaq(-)) and hydrogen atom (H) with these pollutants were also obtained by means of competition kinetics, using 3-aminopyridine and atrazine as reference compounds. The results indicated that the elimination of these pollutants with gamma radiation mainly follows the oxidative pathway through reaction with HO radicals. The degradation by-products from the five pollutants were determined, detecting that the hydroxylation of the corresponding parent compounds was the main chemical process in the degradation of the pollutants. Moreover, a high decrease in the chemical oxygen demand has been observed for all pollutants. As expected, the degradation by-products generated by the irradiation of PA, BPA and DPA showed a lower toxicity than the parent compounds, however, in the case of 2,4-D and MCPA irradiation, interestingly, their by-products were more toxic than the corresponding original compounds. PMID:27366982

  10. Comparison of Free and Immobilized L-asparaginase Synthesized by Gamma-Irradiated Penicillium cyclopium.

    PubMed

    El-Refai, Heba A; Shafei, Mona S; Mostafa, Hanan; El-Refai, Abdel-Monem H; Araby, Eman M; El-Beih, Fawkia M; Easa, Saadia M; Gomaa, Sanaa K

    2016-01-01

    Gamma irradiation is used on Penicillium cyclopium in order to obtain mutant cells of high L-asparaginase productivity. Using gamma irradiation dose of 4 KGy, P. cyclopium cells yielded L-asparaginase with extracellular enzyme activity of 210.8 ± 3 U/ml, and specific activity of 752.5 ± 1.5 U/mg protein, which are 1.75 and 1.53 times, respectively, the activity of the wild strain. The enzyme was partially purified by 40-60% acetone precipitation. L-asparaginase was immobilized onto Amberlite IR-120 by ionic binding. Both free and immobilized enzymes exhibited maximum activity at pH 8 and 40 degrees C. The immobilization process improved the enzyme thermal stability significantly. The immobilized enzyme remained 100% active at temperatures up to 60 degrees C, while the free asparaginase was less tolerant to high temperatures. The immobilized enzyme was more stable at pH 9.0 for 50 min, retaining 70% of its relative activity. The maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) of the free form were significantly changed after immobilization. The K(m) value for immobilized L-asparaginase was about 1.3 times higher than that of free enzyme. The ions K+, Ba2+ and Na+ showed stimulatory effect on enzyme activity with percentages of 110%, 109% and 106% respectively.

  11. Effects of annealing treatment and gamma irradiation on the absorption and fluorescence spectra of Cr:GSGG laser crystal

    NASA Astrophysics Data System (ADS)

    Sun, D. L.; Luo, J. Q.; Xiao, J. Z.; Zhang, Q. L.; Jiang, H. H.; Yin, S. T.; Wang, Y. F.; Ge, X. W.

    2008-09-01

    The influence of annealing treatments and gamma-ray irradiation on the absorption and fluorescence spectra of Cr:GSGG crystals grown by the Czochralski method has been investigated. Two absorption bands located near 686 nm and 1050 nm were weakened markedly after the crystal was re-annealed in H2 atmosphere, which is due to the Cr4+ ions being de-oxidized into Cr3+ ions. The other two weak additional absorption bands induced by gamma-ray irradiation appearing near 310 nm and 480 nm are ascribed to the Fe2+ ions and F-type color centers, respectively. In particular, the gamma-ray irradiation with a dose of 100 Mrad has an effect of improving slightly the luminescence properties of Cr:GSGG crystals. The improvement mechanism is analyzed and discussed.

  12. Ionizing/displacement synergistic effects induced by gamma and neutron irradiation in gate-controlled lateral PNP bipolar transistors

    NASA Astrophysics Data System (ADS)

    Wang, Chenhui; Chen, Wei; Yao, Zhibin; Jin, Xiaoming; Liu, Yan; Yang, Shanchao; Wang, Zhikuan

    2016-09-01

    A kind of gate-controlled lateral PNP bipolar transistor has been specially designed to do experimental validations and studies on the ionizing/displacement synergistic effects in the lateral PNP bipolar transistor. The individual and mixed irradiation experiments of gamma rays and neutrons are accomplished on the transistors. The common emitter current gain, gate sweep characteristics and sub-threshold sweep characteristics are measured after each exposure. The results indicate that under the sequential irradiation of gamma rays and neutrons, the response of the gate-controlled lateral PNP bipolar transistor does exhibit ionizing/displacement synergistic effects and base current degradation is more severe than the simple artificial sum of those under the individual gamma and neutron irradiation. Enough attention should be paid to this phenomenon in radiation damage evaluation.

  13. EPR spectra induced by gamma-irradiation of some dry medical herbs

    NASA Astrophysics Data System (ADS)

    Yordanov, N. D.; Lagunov, O.; Dimov, K.

    2009-04-01

    The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050±0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show "cellulose-like" EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050±0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the "cellulose-like" EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as "carbohydrate-like" type. Only one intense EPR singlet with g=2.0048±0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months.

  14. Induction of antigen-specific Th1-type immune responses by gamma-irradiated recombinant Brucella abortus RB51.

    PubMed

    Sanakkayala, Neelima; Sokolovska, Anna; Gulani, Jatinder; Hogenesch, Harm; Sriranganathan, Nammalwar; Boyle, Stephen M; Schurig, Gerhardt G; Vemulapalli, Ramesh

    2005-12-01

    Brucella abortus strain RB51 is an attenuated rough mutant used as the live vaccine against bovine brucellosis in the United States and other countries. We previously reported the development of strain RB51 as a bacterial vaccine vector for inducing Th1-type immune responses against heterologous proteins. Because safety concerns may preclude the use of strain RB51-based recombinant live vaccines, we explored the ability of a gamma-irradiated recombinant RB51 strain to induce heterologous antigen-specific immune responses in BALB/c mice. Exposure of strain RB51G/LacZ expressing Escherichia coli beta-galactosidase to a minimum of 300 kilorads of gamma radiation resulted in complete loss of replicative ability. These bacteria, however, remained metabolically active and continued to synthesize beta-galactosidase. A single intraperitoneal inoculation of mice with 10(9) CFU equivalents of gamma-irradiated, but not heat-killed, RB51G/LacZ induced a beta-galactosidase-specific Th1-type immune response. Though no obvious differences were detected in immune responses to B. abortus-specific antigens, mice vaccinated with gamma-irradiated, but not heat-killed, RB51G/LacZ developed significant protection against challenge with virulent B. abortus. In vitro experiments indicated that gamma-irradiated and heat-killed RB51G/LacZ induced maturation of dendritic cells; however, stimulation with gamma-irradiated bacteria resulted in more interleukin-12 secretion. These results suggest that recombinant RB51 strains exposed to an appropriate minimum dose of gamma radiation are unable to replicate but retain their ability to stimulate Th1 immune responses against the heterologous antigens and confer protection against B. abortus challenge in mice.

  15. The influence of antiorthostatic unloading and long gamma-irradiation on rat bone marrow (MSCs)

    NASA Astrophysics Data System (ADS)

    Roe, Maria; Bobyleva, Polina; Shtemberg, Andrey; Buravkova, Ludmila

    With the prospect of long interplanetary spaceflight becoming a real possibility there are some important questions that need to be answered regarding the combined effects of microgravity and long gamma-irradiation.The aim of this study was to evaluate the effects of synchronous antiorthostatic unloading and fractional gamma-irradiation on the functional characteristics of rat bone marrow multipotent stromal cells (MSCs).This experiment was carried out following all rules laid out by the Commission on Bioethics at the SSC RF - IBMP RAS. In this experiment the Wistar rats were kept in an unloaded position for a duration of 30 days. They were also subjected to 6 doses of gamma-radiation on the “GOBO-60” with a source of (137) Cs. The dose rate set to 1 meter 50 sGr / H (Total dose of 3 Gr).The study revealed a significant reduction in the number of colonies (CFU-F) in all cultures from the experimental groups when compared to the control groups. The most significant reduction was observed in the group, which had been subject to combined unloading, and radiation. This result was confirmed by examination of cell cultures during 10 days of growth.We found that the CD45 expression was increased in the groups exposed to radiation. At the same time a reduction in the expression of CD90 was observed during combination of radiation and unloading we found.The experimental groups also differed from the control group showing smaller lipid inclusions and decreased expression of alkaline phosphates in the MSCs. This experiment concluded that the bone marrow MSCs after a combination of unloading and multiple radiation sessions, showed a decrease in proliferation and differentiation potential which could reduce the adaption and reparative capacity of the organism.

  16. Thermoluminescence Study of Gamma Irradiated Cr-Doped LiF Phosphors

    NASA Astrophysics Data System (ADS)

    Kumar, Satinder; Gathania, A. K.; Vij, Ankush; Kumar, Ravi

    2016-06-01

    We have synthesized Cr-doped LiF phosphors by using modified co-precipitation. X-ray diffraction study confirms the single-phase cubic structure up to 0.05 mol.% of Cr in LiF; afterwards, a secondary phase of formation was observed. The field emission scanning electron microscope (FESEM) images revealed micro-cubic surface morphology of samples. The thermoluminescent (TL) behavior of the samples studied after irradiating them with gamma rays in the dose range 0.1-30 kGy. The TL glow curve of Cr-doped LiF comprises a prominent peak observed at 407 K and a broad band ranging from 448 K to 512 K at a fixed gamma dose of 10 kGy. The shape of the TL glow curve remained similar at all concentrations of Cr in LiF; however, TL intensity was found to vary with Cr concentration, and Cr (0.02 mol.%)-doped LiF sample exhibit highest TL response. The glow curve of the optimized sample as a function of gamma irradiation dose within the range 0.1-30 kGy shows an almost linear increase in TL intensity of the main glow peak up to 10 kGy, and afterwards it decreases. Further, at the high dose of 30 kGy, the intensity of the prominent TL glow peak at 407 K decreases and another broad peak starts growing at 468 K signifying the formation of new trapping sites. The kinetic parameters, namely activation energy, order of kinetics, and frequency factor of the optimized sample were evaluated by using Chen's peak shape method and glow curve deconvolution (GCD) functions based on Kitti's equations.

  17. Effect of N-acetyl-l-cysteine on Saccharomyces cerevisiae irradiated with gamma-rays.

    PubMed

    Kim, Jin Kyu; Park, Jiyoung; Ryu, Tae Ho; Nili, Mohammad

    2013-07-01

    Ionizing radiation (IR) induces DNA strand breaks (DSBs), base damage, inhibition of protein activity, apoptosis by reactive oxygen species (ROS). Detoxification or removal of generated ROS can reduce oxidative damage. Antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase are immediately triggered for ROS scavenging. N-acetyl-l-cysteine (NAC) having a thiol, a precursor for reduced glutathione (GSH), is known as one of the antioxidants. In this study, the effect of NAC as an antioxidant and a radioprotector was investigated on survival rate, transcriptional level of antioxidant enzymes gene, and protein level including SOD activity and intracellular GSH in yeast Saccharomyces cerevisiae W303-1A strain mutated YBP1 gene irradiated with gamma-rays. NAC did not protect the gamma-ray-induced cell death. The gene expression of antioxidant enzymes including SOD1, SOD2, GPX1, and GPX2 was induced by gamma-rays. In contrast, the pretreatment of NAC reduced the expression of these genes. NAC reduced SOD activity and intracellular GSH level in yeast. These data suggest that NAC is able to reduce radiation-induced ROS levels in vivo but does not protect yeast cells against radiation-induced death.

  18. Effect of N-acetyl-l-cysteine on Saccharomyces cerevisiae irradiated with gamma-rays.

    PubMed

    Kim, Jin Kyu; Park, Jiyoung; Ryu, Tae Ho; Nili, Mohammad

    2013-07-01

    Ionizing radiation (IR) induces DNA strand breaks (DSBs), base damage, inhibition of protein activity, apoptosis by reactive oxygen species (ROS). Detoxification or removal of generated ROS can reduce oxidative damage. Antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase are immediately triggered for ROS scavenging. N-acetyl-l-cysteine (NAC) having a thiol, a precursor for reduced glutathione (GSH), is known as one of the antioxidants. In this study, the effect of NAC as an antioxidant and a radioprotector was investigated on survival rate, transcriptional level of antioxidant enzymes gene, and protein level including SOD activity and intracellular GSH in yeast Saccharomyces cerevisiae W303-1A strain mutated YBP1 gene irradiated with gamma-rays. NAC did not protect the gamma-ray-induced cell death. The gene expression of antioxidant enzymes including SOD1, SOD2, GPX1, and GPX2 was induced by gamma-rays. In contrast, the pretreatment of NAC reduced the expression of these genes. NAC reduced SOD activity and intracellular GSH level in yeast. These data suggest that NAC is able to reduce radiation-induced ROS levels in vivo but does not protect yeast cells against radiation-induced death. PMID:23623538

  19. Response of thyroid follicular cells to gamma irradiation compared to proton irradiation. I. Initial characterization of DNA damage, micronucleus formation, apoptosis, cell survival, and cell cycle phase redistribution

    NASA Technical Reports Server (NTRS)

    Green, L. M.; Murray, D. K.; Bant, A. M.; Kazarians, G.; Moyers, M. F.; Nelson, G. A.; Tran, D. T.

    2001-01-01

    The RBE of protons has been assumed to be equivalent to that of photons. The objective of this study was to determine whether radiation-induced DNA and chromosome damage, apoptosis, cell killing and cell cycling in organized epithelial cells was influenced by radiation quality. Thyroid-stimulating hormone-dependent Fischer rat thyroid cells, established as follicles, were exposed to gamma rays or proton beams delivered acutely over a range of physical doses. Gamma-irradiated cells were able to repair DNA damage relatively rapidly so that by 1 h postirradiation they had approximately 20% fewer exposed 3' ends than their counterparts that had been irradiated with proton beams. The persistence of free ends of DNA in the samples irradiated with the proton beam implies that either more initial breaks or a quantitatively different type of damage had occurred. These results were further supported by an increased frequency of chromosomal damage as measured by the presence of micronuclei. Proton-beam irradiation induced micronuclei at a rate of 2.4% per gray, which at 12 Gy translated to 40% more micronuclei than in comparable gamma-irradiated cultures. The higher rate of micronucleus formation and the presence of larger micronuclei in proton-irradiated cells was further evidence that a qualitatively more severe class of damage had been induced than was induced by gamma rays. Differences in the type of damage produced were detected in the apoptosis assay, wherein a significant lag in the induction of apoptosis occurred after gamma irradiation that did not occur with protons. The more immediate expression of apoptotic cells in the cultures irradiated with the proton beam suggests that the damage inflicted was more severe. Alternatively, the cell cycle checkpoint mechanisms required for recovery from such damage might not have been invoked. Differences based on radiation quality were also evident in the alpha components of cell survival curves (0.05 Gy(-1) for gamma rays, 0

  20. The effects of gamma irradiation on micro-hotplates with integrated temperature sensing diodes

    NASA Astrophysics Data System (ADS)

    Francis, Laurent A.; André, Nicolas; Boufouss, El Hafed; Gérard, Pierre; Ali, Zeeshan; Udrea, Florin; Flandre, Denis

    2014-06-01

    Micro-hotplates are MEMS structures of interest for low-power gas sensing, lab-on-chips and space applications, such as micro-thrusters. Micro-hotplates usually consist in a Joule heater suspended on a thin-film membrane while thermopiles or thermodiodes are added as temperature sensors and for feedback control. The implementation of micro-hotplates using a Silicon-On-Insulator technology makes them suited for co-integration with analog integrated circuits and operation at elevated environmental temperatures in a range from 200 to 300 °C, while the heater allows thermal cycling in the kHz regime up to 700 °C, e.g. necessary for the activation of gas sensitive metal-oxide on top of the membrane, with mWrange electrical power. The demonstrated resistance of micro-hotplates to gamma radiations can extend their use in nuclear plants, biomedical sterilization and space applications. In this work, we present results from electrical tests on micro-hotplates during their irradiation by Cobalt-60 gamma rays with total doses up to 18.90 kGy. The micro-hotplates are fabricated using a commercial 1.0 μm Silicon-On-Insulator technology with a tungsten Joule heater, which allows power-controlled operation above 600 °C with less than 60 mW, and temperature sensing silicon diodes located on the membrane and on the bulk. We show the immunity of the sensing platform to the harsh radiation environment. Beside the good tolerance of the thermodiodes and the membrane materials to the total radiation dose, the thermodiode located on the heating membrane is constantly annealed during irradiation and keeps a constant sensitivity while post-irradiation annealing can restore the thermodiode.

  1. Optical absorption of gamma-irradiated lithium-borate glasses doped with different transition metal oxides

    NASA Astrophysics Data System (ADS)

    Marzouk, S. Y.; Elalaily, N. A.; Ezz-Eldin, F. M.; Abd-Allah, W. M.

    2006-06-01

    We have investigated the effect of gamma irradiation on the optical properties of Li 2O-B 2O 3 containing two concentrations (0.2 or 0.5 g) of each one of the following transition metals, V, Mn, Fe or Ni oxide glass samples. We studied the impacts of gamma irradiation in terms of the mechanism by which radiation-induced defects are generated. A resolution of the observed absorption spectra showed several bands which were induced by photo-reduction or photo-oxidation assumed to take place by photo-chemical reaction according to the type of transition metal oxide (TMO). Small deviations of these induced bands characteristic of the glass constituents were observed and explained in terms of the physical properties, in relation to different oxidation states of TMO in the glass matrix. The series Mn 2+, Fe 2+ and Ni 2+ ions shows a trend of increased photo-oxidation with increasing electronegativity or decreasing mass of the ions. The prepared samples were studied in terms of their dosimetric characteristics: calibration curves from 1.0524 to 42.096 kGy and fading at (25 and 50 °C). Thermal bleaching of irradiated glass was found to permit the reduction of the larger part of TMO ions in Li 2O-B 2O 3. Also, the results showed that the degeneration of the induced bands was faster at 50 than at 25 °C. The optical energy gap Eg was found to decrease with the increase of the radiation dose, and it is suggested that the mechanism of optical transition is forbidden by indirect transition.

  2. Hesperidin a flavanoglycone protects against gamma-irradiation induced hepatocellular damage and oxidative stress in Sprague-Dawley rats.

    PubMed

    Pradeep, Kannampalli; Park, Sang Hyun; Ko, Kyong Cheol

    2008-06-10

    Oxidative stress plays a pivotal role in the pathogenesis and progression of gamma-irradiation induced cellular damage and the administration of dietary antioxidants has been suggested to protect against the subsequent tissue damage. Here, we present the data to explore the hepatoprotective and antioxidant effect of hesperidin, a naturally occurring citrus flavanoglycone, against gamma-irradiation induced oxidative damage in the liver of rats. Healthy male Sprague-Dawley rats were exposed to gamma-irradiation (1 Gy, 3 Gy and 5 Gy) and were administered hesperidin (50 mg/kg and 100 mg/kg, b.w, orally) for 7 days post irradiation. The changes in body weight, liver weight, spleen index, serum and liver aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), gamma-glutamyl transpeptidase (gamma-GT) and serum ceruloplasmin levels were determined along with differences in the liver histopathology. Liver thiobarbuturic acid reactive substance as an index for lipid peroxidation and the levels of enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase and the status of non-enzymatic antioxidants as an index for oxidative stress were also determined. Exposure to gamma-irradiation resulted in hepatocellular damage in a dose-dependent manner, featuring a significantly decreased body weight and liver weight and higher levels of serum AST, ALT, ALP, LDH and gamma-GT levels and a simultaneous decrease in their levels in the liver tissue. Oxidative stress was evidenced by elevated levels of lipid peroxidation and a decrease in the levels of key enzymatic and non-enzymatic antioxidants in the liver. However, the gamma-irradiation induced toxic effects were dramatically and dose-dependently inhibited by hesperidin treatment as observed by the restoration in the altered levels of the marker enzymes, lipid peroxidation, enzymatic and non-enzymatic antioxidants. The results of the biochemical

  3. Qualitative and Quantitative Assessment of Sewage Sludge by Gamma Irradiation with Pasteurization as a Tool for Hygienization

    NASA Astrophysics Data System (ADS)

    Priyadarshini, J.; Roy, P. K.; Mazumdar, A.

    2014-01-01

    In this research work, management of sewage sludge disposal on agricultural soils is addressed. The increasing amount of sewage sludge and more legislative regulation of its disposal have stimulated the need for developing new technologies to recycle sewage sludge efficiently. The research was structured along two main avenues, namely, the efficacy of the irradiation process for removing enteric pathogenic microorganisms and the potential of irradiated sludge as a soil amendment. This study investigated how application of irradiation with heat treatment reduced pathogens in sewage sludge. Raw and pasteurised Sewage sludge was treated at different dose treatment of 1.5, 3 and 5 kilogray (kGy) gamma irradiation individually and for 3 kGy sufficiency was achieved. Decrease in irradiation dose from 5 to 3 kGy was observed for pasteurised sludge resulting in saving of radiation energy. The presence of heavy metals in untreated sewage sludge has raised concerns, which decreases after irradiation.

  4. Assessing the effects of gamma irradiation and storage time in energetic value and in major individual nutrients of chestnuts.

    PubMed

    Fernandes, Angela; Barreira, João C M; Antonio, Amilcar L; Bento, Albino; Luisa Botelho, M; Ferreira, Isabel C F R

    2011-09-01

    Chestnut (Castanea sativa Miller) is an important food resource all over the world. In the present study, it is intended to evaluate if the application of gamma irradiation doses ≤ 3 kGy maintain chestnuts chemical and nutritional profiles unaffected. Furthermore, possible interactions among irradiation dose and storage time were accessed using linear discriminate analysis (LDA). The nutritional composition was evaluated through determination of proteins, fat, ash, carbohydrates and energetic value. The chemical composition was focused in the main nutrients found in chestnuts: sugars - sucrose, fatty acids - palmitic, oleic, linoleic and linolenic acids, tocopherols - γ-tocopherol. The obtained results seem to indicate that the irradiation treatment did not affect the nutritional and chemical quality of chestnut fruits. Otherwise, storage time exerted more evident influence in those parameters. The application of gamma irradiation emerges as a promising technology for chestnuts chemical quality, but food safety issues have to be evaluated in order to recommend its application as a useful conservation alternative.

  5. Effect of gamma irradiation on the vitamins, phytochemicals, antimicrobial and antioxidant properties of Ziziphus mauritiana Lam. leaves

    NASA Astrophysics Data System (ADS)

    Khattak, Khanzadi Fatima; Rahman, Taj Ur

    2016-10-01

    Plant based food products and medicines are given more consideration for their efficacy, safety and synergistic effects. Radiation processing has been valuably used for microbial decontamination and value addition of the plant materials. The current study is about the effect of gamma irradiation on the quality attributes of Ziziphus mauritiana Lam. leaves. The leaves of the plant were irradiated at the dose levels of 2.5, 5.0, 7.5, 10.0 and 12.5 kGy. The irradiated and control samples were evaluated for vitamin, phytochemicals, antibacterial and DPPH scavenging activities. The results showed that gamma irradiation doses up to 12.5 kGy enhanced the levels of certain phytochemicals and augmented the biological activities.

  6. Studies on enhancing the keeping quality of peach ( Prunus persica Bausch) Cv. Elberta by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Hussain, P. R.; Meena, R. S.; Dar, M. A.; Wani, A. M.

    2008-04-01

    The effect of gamma-irradiation on keeping quality of peach fruit was studied. The fruit, after harvesting at proper maturity stage, was irradiated in the dose range of 1.0-2.0 kGy, stored under ambient (temp. 25±2 °C, RH 70%) and refrigerated (temp. 3±1 °C, RH 80%) conditions and evaluated periodically for firmness, total soluble solids (TSS), anthocyanins, water-soluble pectic fractions, loss in weight and decay percentage. The anthocyanin evaluation of the fruits revealed that irradiation enhanced the colour development under both the storage conditions. The gamma-irradiation dose range of 1.2-1.4 kGy proved effective in maintaining higher TSS concentration, reducing weight loss and significantly ( p⩽0.05) delaying the decaying of the fruit by 6 days under ambient conditions and by 20 days under refrigerated storage conditions.

  7. Gamma irradiation of air-dried olive leaves: Effective decontamination and impact on the antioxidative properties and on phenolic compounds.

    PubMed

    Aouidi, Fathia; Ayari, Samia; Ferhi, Hana; Roussos, Sevastianos; Hamdi, Moktar

    2011-08-01

    Olive leaves are commercialized for their antioxidative value due to their valuable phenolic compounds. The present study aimed to evaluate the effect of gamma irradiation on microbial load, on antioxidative properties and on phenolic compounds of air-dried olive leaves. Irradiation was applied up to 25kGy (5kGy intervals) to powdered and intact samples. Total aerobic bacteria, yeast and mold, and lactic acid bacteria were counted after gamma irradiation. Decontamination was obtained at 20kGy. The radioresistance of microbial population was high with D10 values between 9.74 and 25.12kGy. Besides, gamma irradiation up to 25kGy was found to maintain the antioxidant capacity, molecular mass distribution of polyphenolics, total phenolics, ortho-diphenols, flavonoids, oleuropein, verbascoside and rutin contents. To conclude, the improvement of the microbial quality of air-dried olive leaves, without affecting phenolic composition and antioxidative properties, can be successively achieved by the application of gamma irradiation treatment. PMID:25214102

  8. Detection and original dose assessment of egg powders subjected to gamma irradiation by using ESR technique

    NASA Astrophysics Data System (ADS)

    Aydın, Talat

    2015-09-01

    ESR (electron spin resonance) techniques were applied for detection and original dose estimation to radiation-processed egg powders. The un-irradiated (control) egg powders showed a single resonance line centered at g=2.0086±0.0005, 2.0081±0.0005, 2.0082±0.0005 (native signal) for yolk, white and whole egg, respectively. Irradiation induced at least one additional intense singlet overlapping to the control signal and caused a significant increase in signal intensity without any changes in spectral patterns. Responses of egg powders to different gamma radiation doses in the range 0-10 kGy were examined. The stability of the radiation-induced ESR signal of irradiated egg powders were investigated over a storage period of about 5 months. Additive reirradiation of the egg powders produces a reproducible dose response function, which can be used to assess the initial dose by back-extrapolation. The additive dose method gives an estimation of the original dose within ±12% at the end of the 720 h storage period.

  9. Physicochemical and thermal properties of gamma-irradiated sago (Metroxylon sagu) starch

    NASA Astrophysics Data System (ADS)

    Othman, Zainon; Hassan, Osman; Hashim, Kamaruddin

    2015-04-01

    Sago (Metroxylon sagu) starch was exposed to gamma-irradiation in air at doses 6, 10 and 25 kGy. Subsequent changes in the physicochemical and thermal properties were measured. The apparent amylose content and swelling power of irradiated sago starch was significantly reduced while reducing sugars and starch solubility were significantly increased due to degradation. X-ray diffraction studies showed that radiation did not affect the crystalline type but induced a decrease in the degree of crystallinity, indicating the destruction of the ordered distribution of neighboring polysaccharide chains in the starch granules, in particular of the amylopectin component, which is responsible for starch crystallinity. Differential scanning calorimetry (DSC) of irradiated sago starch showed a small but significant increase in the onset and peak transition temperatures at 10 and 25 kGy dose; the conclusion temperature and gelatinization enthalpy was not affected. SEM and particle size analysis produced no evidence of physical damage to sago starch up to 25 kGy dose radiation treatment since the granular appearance and size distribution was retained.

  10. Effect of gamma irradiation on the structural and magnetic properties of Co–Zn spinel ferrite nanoparticles

    SciTech Connect

    Raut, Anil V.; Kurmude, D.V.; Shengule, D.R.; Jadhav, K.M.

    2015-03-15

    Highlights: • Co–Zn ferrite nanoparticles were examined before and after γ-irradiation. • Single phase cubic spinel structure of Co–Zn was confirmed by XRD data. • The grain size was reported in the range of 52–62 nm after γ-irradiation. • Ms, Hc, n{sub B} were reported to be increased after gamma irradiation. - Abstract: In this work, the structural and magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co–Zn ferrite nanoparticles prepared by sol–gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co{sup 60} γ-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co–Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (α) and other structural parameters of gamma-irradiated and un-irradiated Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n{sub B}) etc. magnetic parameters were increased after irradiation.

  11. Effects of stearic acid and gamma irradiation, alone and in combination, on pasting properties of high amylose maize starch.

    PubMed

    Ocloo, Fidelis C K; Minnaar, Amanda; Emmambux, Naushad M

    2016-01-01

    The effects of stearic acid and gamma irradiation on pasting properties of high amylose maize starch (HAMS) were studied. Stearic acid (0%, 1.5%, and 5%) was added to HAMS, and then irradiated at 0, 30, and 60 kGy before pasting. Stearic acid increased the paste viscosity of un-irradiated HAMS from 420 mPas to 557 and 652 mPas for 1.5% and 5% stearic acid, respectively. This observation related well with the formation of type II amylose-lipid complexes, with melting temperatures of about 100-120 °C. Gamma irradiation (30 and 6 0kGy) reduced pasting viscosity of HAMS. Pasting of gamma irradiated HAMS resulted in the formation of type I amylose-lipid complexes, with melting temperatures and enthalpies ranging from 82 to 102 °C and 0.22 to 1.85 J/g, respectively. Stearic acid addition followed by irradiation creates means of producing different types of amylose-lipid complexes from HAMS for industrial utilization.

  12. Structural and optical analysis of 60Co gamma-irradiated thin films of polycrystalline Ga10Se85Sn5

    NASA Astrophysics Data System (ADS)

    Ahmad, Shabir; Asokan, K.; Shahid Khan, Mohd.; Zulfequar, M.

    2015-12-01

    The present study focuses on the effects of gamma irradiation on structural and optical properties of polycrystalline Ga10Se85Sn5 thin films with a thickness of ∼300 nm deposited by the thermal evaporation technique on cleaned glass substrates. X-ray diffraction patterns of the investigated thin films show that crystallite growth occurs in the orthorhombic phase structure. The surface study carried out by using the scanning electron microscope (SEM) confirms that the grain size increases with gamma irradiation. The optical parameters were estimated from optical transmission spectra data measured from a UV-vis-spectrophotometer in the wavelength range of 200-1100 nm. The refractive index dispersion data of the investigated thin films follow the single oscillator model. The estimated values of static refractive index n0, oscillator strength Ed, zero frequency dielectric constant ε0, optical conductivity σoptical and the dissipation factor increases after irradiation, while the single oscillator energy Eo decreases after irradiation. It was found that the value of the optical band gap of the investigated thin films decreases and the corresponding absorption coefficient increases continuously with an increase in the dose of gamma irradiation. This post irradiation changes in the values of optical band gap and absorption coefficient were interpreted in terms of the bond distribution model.

  13. Effects of gamma irradiation on the radiation-resistant bacteria and polyphenol oxidase activity in fresh kale juice

    NASA Astrophysics Data System (ADS)

    Kim, Dongho; Song, Hyunpa; Lim, Sangyong; Yun, Hyejeong; Chung, Jinwoo

    2007-07-01

    Gamma radiation was performed to prolong the shelf life of natural kale juice. The total aerobic bacteria in fresh kale juice, prepared by a general kitchen process, was detected in the range of 10 6 cfu/ml, and about 10 2 cfu/ml of the bacteria survived in the juice in spite of gamma irradiation treatment with a dose of 5 kGy. Two typical radiation-resistant bacteria, Bacillus megaterium and Exiguobacterium acetylicum were isolated and identified from the 5 kGy-irradiated kale juices. The D10 values of the vegetative cell and endospore of the B. megaterium in peptone water were 0.63±0.05 and 1.52±0.05 kGy, respectively. The D10 value of the E. acetylicum was calculated as 0.65±0.06 kGy. In the inoculation test, the growth of the surviving B. megaterium and E. acetylicum in the 3-5 kGy-irradiated kale juice retarded and/or decreased significantly during a 3 d post-irradiation storage period. However, there were no significant differences in the residual polyphenol oxidase activity and browning index between the nonirradiated control and the gamma irradiated kale juice during a post-irradiation period.

  14. Characterization and dosimetry of a practical X-ray alternative to self-shielded gamma irradiators

    NASA Astrophysics Data System (ADS)

    Mehta, Kishor; Parker, Andrew

    2011-01-01

    The Insect Pest Control Laboratory of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture recently purchased an X-ray irradiator as part of their programme to develop the sterile insect technique (SIT). It is a self-contained type with a maximum X-ray beam energy of 150 keV using a newly developed 4 π X-ray tube to provide a very uniform dose to the product. This paper describes the results of our characterization study, which includes determination of dose rate in the centre of a canister as well as establishing absorbed dose distribution in the canister. The irradiation geometry consists of five canisters rotating around an X-ray tube—the volume of each canister being 3.5 l. The dose rate at the maximum allowed power of the tube (about 6.75 kW) in the centre of a canister filled with insects (or a simulated product) is about 14 Gy min -1. The dose uniformity ratio is about 1.3. The dose rate was measured using a Farmer type 0.18-cm 3 ionization chamber calibrated at the relevant low photon energies. Routine absorbed dose measurement and absorbed dose mapping can be performed using a Gafchromic® film dosimetry system. The radiation response of Gafchromic film is almost independent of X-ray energy in the range 100-150 keV, but is very sensitive to the surrounding material with which it is in immediate contact. It is important, therefore, to ensure that all absorbed dose measurements are performed under identical conditions to those used for the calibration of the dosimetry system. Our study indicates that this X-ray irradiator provides a practical alternative to self-shielded gamma irradiators for SIT programmes. Food and Agriculture Organization/International Atomic Energy Agency.

  15. Cytosine arabinoside enhancement of gamma irradiation induced mutations in human T-lymphocytes

    SciTech Connect

    O'Neill, J.P.; Sullivan, L.M.; Hunter, T.C.; Nicklas, J.A. )

    1991-01-01

    The frequency of 6-thioguanine resistant (TGr) mutants induced in human G0 phase T-lymphocytes by 200 cGy of gamma irradiation is greatly enhanced by incubation with cytosine arabinoside (ara-C) after irradiation. The mutant frequency increased with increasing incubation time in ara-C for up to 2 hr. This mutation induction required a phenotypic expression time of 5-8 days mass culture growth, similar to that found with mutants induced by 300 cGy of irradiation alone. Southern blot analysis of 40 isolated mutant clones revealed 8 independent mutations by T-cell receptor (TCR) gene rearrangement patterns. Four of these eight showed hprt gene structural alterations (0.50). An alternative method to allow phenotypic expression was developed to minimize the isolation of hprt/TCR sibling mutants. The use of in situ expression in the microtiter dish wells resulted in the isolation of 17 independent mutations in 19 mutant clones. Ten of these 17 mutations showed hprt structural alterations (0.59). The high fraction of mutations involving structural alterations detected by Southern blot analysis is consistent with the known induction of chromosome aberrations by irradiation plus ara-C treatment. We propose that both the increase in Mf and the increase in the incidence of hprt gene structural alterations are due to the accumulation of strand breaks in repairing regions of DNA under these conditions of ara-C induced inhibition of repair. We further propose that upon release of the ara-C inhibition, these repairing regions can interact to yield both gene mutations and chromosome aberrations.

  16. Evaluation of the Effect of a Gamma Irradiated DBM-Pluronic F127 Composite on Bone Regeneration in Wistar Rat

    PubMed Central

    Canciani, Barbara; Losi, Paola; Tripodi, Maria; Burchielli, Silvia; Ottoni, Priscilla; Salvadori, Piero Antonio; Soldani, Giorgio

    2015-01-01

    Demineralized bone matrix (DBM) is widely used for bone regeneration. Since DBM is prepared in powder form its handling properties are not optimal and limit the clinical use of this material. Various synthetic and biological carriers have been used to enhance the DBM handling. In this study we evaluated the effect of gamma irradiation on the physical-chemical properties of Pluronic and on bone morphogenetic proteins (BMPs) amount in DBM samples. In vivo studies were carried out to investigate the effect on bone regeneration of a gamma irradiated DBM-Pluronic F127 (DBM-PF127) composite implanted in the femur of rats. Gamma irradiation effects (25 kGy) on physical-chemical properties of Pluronic F127 were investigated by rheological and infrared analysis. The BMP-2/BMP-7 amount after DBM irradiation was evaluated by ELISA. Bone regeneration capacity of DBM-PF127 containing 40% (w/w) of DBM was investigated in transcortical holes created in the femoral diaphysis of Wistar rat. Bone porosity, repaired bone volume and tissue organization were evaluated at 15, 30 and 90 days by Micro-CT and histological analysis. The results showed that gamma irradiation did not induce significant modification on physical-chemical properties of Pluronic, while a decrease in BMP-2/BMP-7 amount was evidenced in sterilized DBM. Micro-CT and histological evaluation at day 15 post-implantation revealed an interconnected trabeculae network in medullar cavity and cellular infiltration and vascularization of DBM-PF127 residue. In contrast a large rate of not connected trabeculae was observed in Pluronic filled and unfilled defects. At 30 and 90 days the DBM-PF127 samples shown comparable results in term of density and thickness of the new formed tissue respect to unfilled defect. In conclusion a gamma irradiated DBM-PF127 composite, although it may have undergone a significant decrease in the concentration of BMPs, was able to maintains bone regeneration capability. PMID:25897753

  17. APR-2 Tropical Cyclone Observations

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Tanelli, S.

    2011-01-01

    The Second Generation Airborne Precipitation Radar (APR-2) participated in the Genesis and Rapid Intensification Processes (GRIP) experiment in August and September of 2010, collecting a large volume of data in several tropical systems, including Hurricanes Earl and Karl. Additional measurements of tropical cyclone have been made by APR-2 in experiments prior to GRIP (namely, CAMEX-4, NAMMA, TC4); Table 1 lists all the APR-2 tropical cyclone observations. The APR-2 observations consist of the vertical structure of rain reflectivity at 13.4 and 35.6 GHz, and at both co-polarization and crosspolarization, as well as vertical Doppler measurements and crosswind measurements. APR-2 normally flies on the NASA DC-8 aircraft, as in GRIP, collecting data with a downward looking, cross-track scanning geometry. The scan limits are 25 degrees on either side of the aircraft, resulting in a roughly 10-km swath, depending on the aircraft altitude. Details of the APR-2 observation geometry and performance can be found in Sadowy et al. (2003).The multiparameter nature of the APR-2 measurements makes the collection of tropical cyclone measurements valuable for detailed studies of the processes, microphysics and dynamics of tropical cyclones, as well as weaker systems that are associated with tropical cyclone formation. In this paper, we give a brief overview of how the APR-2 data are processed. We also discuss use of the APR-2 cross-track winds to estimate various quantities of interest in in studies of storm intensification. Finally, we show examples of the standard products and derived information.

  18. Effect of gamma irradiation on lipoxygenases, trypsin inhibitor, raffinose family oligosaccharides and nutritional factors of different seed coat colored soybean (Glycine max L.)

    NASA Astrophysics Data System (ADS)

    Kumar Dixit, Amit; Kumar, Vineet; Rani, Anita; Manjaya, J. G.; Bhatnagar, Deepak

    2011-04-01

    Three soybean genotypes Kalitur, Hara soya and NRC37 with black, green and yellow seed coat color, respectively, were gamma irradiated at 0.5, 2.0 and 5.0 kGy and tested for antinutritional and nutritional factors. Gamma irradiation at all doses reduced the level of lipoxygenase isomers, trypsin inhibitor (TI) and ascorbic acid in all the 3 soybean genotypes as compared to the unirradiated control. However, irradiation dose of 5.0 kGy increased the sucrose content of the soybean genotypes. No significant change was observed in oil, protein fatty acids and total tocopherol content of the 3 genotypes at any irradiation dose. It is suggested that inhibition of lipoxygenase, reduction in TI and ascorbic acid may be due to the breakage or oxidation of protein structure by the gamma irradiation. Similarly, gamma irradiation at higher doses may break glycosidic linkages in oligosaccharides to produce more sucrose and decrease the content of flatulence causing oligosaccharides.

  19. Characterization of Neutron and Gamma Dose in the Irradiation Cell of Texas A and M University Research Reactor

    SciTech Connect

    Vasudevan, Latha; Reece, Warren D.; Chirayath, Sunil S.; Aghara, Sukesh

    2011-07-01

    The Monte Carlo N-Particle (MCNP) code was used to develop a three dimensional computational model of the Texas A and M University Nuclear Science Center Reactor (NSCR) operating against the irradiation (dry cell) at steady state thermal power of 1 MW. The geometry of the NSCR core and the dry cell were modeled in detail. NSCR is used for a wide variety of experiments that utilizes the dry cell for neutron as well as gamma irradiation of samples. Information on the neutron and gamma radiation environment inside the dry cell is required to facilitate irradiation of samples. This paper presents the computed neutron flux, neutron and gamma dose rate, and foil reaction rates in the dry cell, obtained through MCNP5 simulations of the NSCR core. The neutron flux was measured using foil activation method and the reaction rates obtained from {sup 197}Au(n,{gamma}){sup 198}Au and {sup 54}Fe(n,p){sup 54}Mn were compared with the model and they showed agreement within {approx} 20%. The gamma dose rate at selected locations inside the dry cell was measured using radiochromic films and the results indicate slightly higher dose rates than predicted from the model. This is because the model calculated only prompt gamma dose rates during reactor operation while the radiochromic films measured gammas from activation products and fission product decayed gammas. The model was also used to calculate the neutron energy spectra for the energy range from 0.001 eV- 20 MeV. (authors)

  20. Determination of the changes of antifungal properties of Satureja hortensis, Thymus vulgaris and Thymbra spicata exposed to gamma irradiation

    NASA Astrophysics Data System (ADS)

    Gumus, Tuncay

    2010-01-01

    In this research, changes in the antifungal activity of the extract of Satureja hortensis, Thymus vulgaris and Thymbra spicata exposed to gamma irradiation against two aflatoxigenic moulds Aspergillus parasiticus NRRL 2999 and 465 were investigated. The samples of dry plant leaf powder were irradiated with doses of 1.2, 3.0, 5.1 kGy. While the antifungal activity of S. hortensis with 0 and 1.2 kGy dose irradiation against A. parasiticus NRRL 2999 was found to be similar, it decreased with 3.0 and 5.1 kGy irradiation doses ( P<0.05). On the contrary, antifungal activity of T. spicata increased until 3.0 kGy and then it decreased with 5.1 kGy irradiation dose ( P<0.05). For T. vulgaris, an increase of irradiation dose resulted in a decrease of antifungal activity against aflatoxigenic moulds. This research shows that antifungal properties of some spices can be changed by gamma irradiation.

  1. Modifications of Fowler-Nordheim injection characteristics in {gamma} irradiated MOS devices

    SciTech Connect

    Scarpa, A.; Paccagnella, A.; Montera, F.; Candelori, A.; Ghibaudo, G.; Pananakakis, G.; Fuochi, P.G.

    1998-06-01

    In this work the authors have investigated how gamma irradiation affects the tunneling conduction mechanism of a 20 nm thick oxide in MOS capacitors. The radiation induced positive charge is rapidly compensated by the injected electrons, and does not impact the gate current under positive injection after the first current-voltage measurement. Only a transient stress induced leakage current at low gate bias is observed. Instead, a radiation induced negative charge has been observed near the polysilicon gate, which enhances the gate voltage needed for Fowler-Nordheim conduction at negative gate bias. No time decay of this charge has been observed. Such charges slightly modify the trapping kinetics of negative charge during subsequent electrical stresses performed at constant current condition.

  2. Free ion yield observed in liquid isooctane irradiated by gamma rays. Comparison with the Onsager theory.

    PubMed

    Pardo, J; Franco, L; Gómez, F; Iglesias, A; Lobato, R; Mosquera, J; Pazos, A; Pena, J; Pombar, M; Rodríguez, A; Sendón, J

    2004-05-21

    We have analysed data on the free ion yield observed in liquid isooctane irradiated by 60Co gamma rays within the framework of the Onsager theory about initial recombination. Several distribution functions describing the electron thermalization distance have been used and compared with the experimental results: a delta function, a Gaussian-type function and an exponential function. A linear dependence between the free ion yield and the external electric field has been found at low-electric-field values (E < or = 1.2 x 10(3) V mm(-1)) in excellent agreement with the Onsager theory. At higher electric field values, we obtain a solution in power series of the external field using the Onsager theory.

  3. Catalytic poly(vinyl alcohol) functionalized membranes obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Silva, A. G.; Pinto, J. V.; Ramos, A. M.; Vital, J.; Ferreira, L. M.

    2012-09-01

    Polymeric catalytic membranes bearing sulfonic acid functions have been prepared by mutual gamma irradiation at a 60Co source, of poly(vinyl alcohol) (PVA) membranes and methanesulfonic acid. The effect of various synthesis conditions on membranes' physical-chemical properties and catalytic activity in the esterification reaction between acetic acid and isoamyl alcohol to obtain isoamyl acetate (banana flavor), was evaluated. The membranes were characterized by ATR-FTIR, TPP, AFM and SEM. Water contact angle determinations were also performed. The obtained results showed that within the range of conditions studied the increase in sulfonic acid groups' content is accompanied by an enhancement in the membranes catalytic activity, while the increase in absorbed dose leads to a decrease in catalytic activity.

  4. Study of free radicals in gamma irradiated cellulose of cultural heritage materials using Electron Paramagnetic Resonance

    NASA Astrophysics Data System (ADS)

    Kodama, Yasko; Rodrigues, Orlando, Jr.; Garcia, Rafael Henrique Lazzari; Santos, Paulo de Souza; Vasquez, Pablo A. S.

    2016-07-01

    Main subject of this article was to study room temperature stable radicals in Co-60 gamma irradiated contemporary paper using Electron Paramagnetic Resonance spectrometer (EPR). XRD was used to study the effect of ionizing radiation on the morphology of book paper. SEM images presented regions with cellulose fibers and regions with particles agglomeration on the cellulose fibers. Those agglomerations were rich in calcium, observed by EDS. XRD analysis confirmed presence of calcium carbonate diffraction peaks. The main objective of this study was to propose a method using conventional kinetics chemical reactions for the observed radical formed by ionizing radiation. Therefore, further analyses were made to study the half-life and the kinetics of the free radical created. This method can be suitably applied to study radicals on cultural heritage objects.

  5. {gamma} Irradiation-induced degradation of organochlorinated pollutants in fatty esters and in Cod

    SciTech Connect

    Lepine, F.L.; Brochu, F.; Milot, S.

    1995-02-01

    The {gamma} irradiation-induced degradation of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (DDD), and 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE) dissolved in methyl myristate and methyl oleate was studied. DDT and DDE produced DDD and 2,2-bis(4-chlorophenyl)chloroethylene (DDMU) respectively, in agreement with a previous study performed with aliphatic solvents. The degradation of these two former compounds was larger in methyl myristate than in methyl oleate and addition products between methyl myristate and the organochlorines were found. While DDD, DDE, and many PCB congeners in a cod sample were not measurably degraded at 15 KGy, DDT underwent 30% degradation. 9 refs., 1 fig., 2 tabs.

  6. Effect of gamma irradiation on physico-mechanical properties of spice packaging films

    NASA Astrophysics Data System (ADS)

    Mizani, Maryam; Sheikh, Nasrin; Ebrahimi, Samad N.; Gerami, Abas; Tavakoli, Farnaz A.

    2009-09-01

    Physico-mechanical properties of two types of laminated films, commercially used for spice packaging, are investigated after gamma irradiation at 8, 10 and 15 kGy. Data showed that polyethylene terephthalate/polyethylene terephthalate/linear low density polyethylene (PET/PET/LLDPE) was more resistant to radiation compared to biaxially oriented polypropylene/cast polypropylene (BOPP/CPP) and its barrier properties slightly improved up to 15 kGy. Oxygen transmission rate of BOPP/CPP was increased by 25%, and the melting peak temperature was decreased by 3.9% at 15 kGy, which may lead to oxidation of packaged spices and loss of their aroma/flavour, respectively.

  7. Preparation of hydrogels for atopic dermatitis containing natural herbal extracts by gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Lim, Youn-Mook; An, Sung-Jun; Kim, Hae-Kyoung; Kim, Yun-Hye; Youn, Min-Ho; Gwon, Hui-Jeong; Shin, Junhwa; Nho, Young-Chang

    2009-07-01

    Atopic dermatitis (AD) is a familial and chronic inflammatory pruritic skin disease that affects a large number of children and adults in industrialized countries. It is known that one of the prominent features of AD and chronic pruritus is partially due to the histamine released from mast cell. In this work, hydrogel patches with natural herbal extracts were prepared by "freezing and thawing", and a gamma irradiation. It showed eminent healing results as a consequence of long-term moisturizing effects and natural herbal extracts on atopic wounds. Besides its non-toxicity and human harmlessness, it can be easily attached to or detached from the skin without any trace and help patients to feel refreshment when attached. Based on this work, the hydrogel patches we made can be potentially used as an alternative remedy for not only pruritus in AD, but other dermatitis.

  8. Effect of gamma irradiation on the change of solubility and anti-inflammation activity of chrysin in macrophage cells and LPS-injected endotoxemic mice

    NASA Astrophysics Data System (ADS)

    Byun, Eui-Baek; Jang, Beom-Su; Byun, Eui-Hong; Sung, Nak-Yun

    2016-10-01

    This study evaluated the changes of solubility and anti-inflammatory properties of structurally modified gamma-irradiated chrysin. Chrysin was irradiated at various doses for a physical analysis and determining any structural changes and solubility. As shown through the physical analysis, the main peak of the chrysin was decreased as the irradiation dose increased, and it was concomitant with the appearance of several new peaks, which were highly increased in 50 kGy gamma-irradiated chrysin. The solubility was markedly increased in the gamma-irradiated groups. As shown through a physiological analysis, both gamma-irradiated- (15-50 kGy) and intact-chrysin (0 kGy) did not exert cytotoxicity to bone-marrow derived macrophages. The treatment of LPS-stimulated macrophages with 50 kGy gamma-irradiated chrysin resulted in a dose-dependent decrease in pro-inflammatory mediators, such as iNOS-mediated NO, PGE2, COX-2, and cell surface marker (CD80 and CD86), as well as pro-inflammatory cytokines (TNF-α and IL-6), when compared to the intact-chrysin treated group. Mechanically, we found that the inhibition of these pro-inflammatory mediators induced by gamma-irradiated chrysin occurred through an inhibition of MAPKs (ERK1/2 and p38) and the NF-κB signaling pathways. Furthermore, the anti-inflammatory activity remained in the LPS-injected animal model. In this model, gamma-irradiated chrysin treatment highly increased the mouse survival, and significantly decreased the serum cytokine (TNF-α, IL-6 and IL-1β) levels. From these findings, the anti-inflammatory action by gamma-irradiated chrysin may be closely mediated with structural modification. It seems likely that gamma irradiation can be an effective tool for improvement of the physical and physiological properties of polyphenols.

  9. Gamma irradiation as a biological decontaminant and its effect on common fingermark detection techniques and DNA profiling.

    PubMed

    Hoile, Rebecca; Banos, Connie; Colella, Michael; Walsh, Simon J; Roux, Claude

    2010-01-01

    The use of disease-causing organisms and their toxins against the civilian population has defined bioterrorism and opened forensic science up to the challenges of processing contaminated evidence. This study sought to determine the use of gamma irradiation as an effective biological decontaminant and its effect on the recovery of latent fingermarks from both porous and nonporous items. Test items were contaminated with viable spores marked with latent prints and then decontaminated using a cobalt 60 gamma irradiator. Fingermark detection was the focus with standard methods including 1,2-indanedione, ninhydrin, diazafluoren-9-one, and physical developer used during this study. DNA recovery using 20% Chelex extraction and quantitative real-time polymerase chain reaction was also explored. Gamma irradiation proved effective as a bacterial decontaminant with D-values ranging from 458 to 500 Gy for nonporous items and 797-808 Gy for porous ones. The results demonstrated the successful recovery of latent marks and DNA establishing gamma irradiation as a viable decontamination option.

  10. Gamma irradiation as a biological decontaminant and its effect on common fingermark detection techniques and DNA profiling.

    PubMed

    Hoile, Rebecca; Banos, Connie; Colella, Michael; Walsh, Simon J; Roux, Claude

    2010-01-01

    The use of disease-causing organisms and their toxins against the civilian population has defined bioterrorism and opened forensic science up to the challenges of processing contaminated evidence. This study sought to determine the use of gamma irradiation as an effective biological decontaminant and its effect on the recovery of latent fingermarks from both porous and nonporous items. Test items were contaminated with viable spores marked with latent prints and then decontaminated using a cobalt 60 gamma irradiator. Fingermark detection was the focus with standard methods including 1,2-indanedione, ninhydrin, diazafluoren-9-one, and physical developer used during this study. DNA recovery using 20% Chelex extraction and quantitative real-time polymerase chain reaction was also explored. Gamma irradiation proved effective as a bacterial decontaminant with D-values ranging from 458 to 500 Gy for nonporous items and 797-808 Gy for porous ones. The results demonstrated the successful recovery of latent marks and DNA establishing gamma irradiation as a viable decontamination option. PMID:20002271

  11. Effects of high-temperature anneals and {sup 60}Co gamma-ray irradiation on strained silicon on insulator

    SciTech Connect

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

    2007-10-01

    Strained silicon on insulator was exposed to high-temperature annealing and high-dose {sup 60}Co gamma ({gamma})-ray irradiation to study the tenacity of the bond between the strained Si film and the underlying buried oxide. During the high-temperature anneals, the samples were ramped at a rate of 150 deg. C/s to 850 deg. C then ramped to 1200, 1250, and 1300 deg. C at a rate of approximately 5x10{sup 5} deg. C/s for millisecond duration anneals. For the irradiation experiments, the samples were irradiated with {sup 60}Co {gamma} rays to a dose of 51.5 kGy. All samples were characterized by ultraviolet (UV) Raman, pseudo metal-oxide-semiconductor field-effect transistor ({psi}-MOSFET) current voltage, Hall mobility, and photoluminescence (PL) to verify changes in strain. UV Raman, PL, and {psi}-MOSFET measurements show no strain relaxation for the high-temperature annealed samples and only very slight relaxation for the {gamma}-ray irradiated samples.

  12. Furan formation from fatty acids as a result of storage, gamma irradiation, UV-C and heat treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Furan is a possible human carcinogen that has been found in many thermally processed foods. The effects of thermal processing, gamma and UV-C irradiation on formation of furan from different fatty acids was studied. In addition, formation of furan from fatty acid emulsions during storage at 25C and...

  13. Characterization and identification of gamma-irradiated sauces by electron spin resonance spectroscopy using different sample pretreatments.

    PubMed

    Akram, Kashif; Ahn, Jae-Jun; Kwon, Joong-Ho

    2013-06-01

    Tomato ketchup, barbeque sauce, sweet chili sauce, and spaghetti sauce were gamma irradiated at 0, 1, 5, and 10 kGy. Electron spin resonance (ESR) technique was used to characterize the irradiated sauces, targeting radiation-induced cellulose radicals and using a modified sample pretreatment method. The samples were first washed with water, and then the residues were extracted with alcohol. The non-irradiated sauces exhibited the single central signal, whose intensity showed a significant increase on irradiation. The ESR spectra from the radiation-induced cellulose radicals, with two side peaks (g=2.02012 and g=1.98516) equally spaced (± 3 mT) from the central signal, were also observed in the irradiated sauces. The improvements in the central (natural) and radiation-induced (two side peaks corresponding to the cellulose radicals) signal intensities were obvious, when compared with routine freeze-drying and alcoholic-extraction techniques. PMID:23411320

  14. [Comparative study of effect of infrared, submillimeter, and millimeter electromagnetic radiation on wing somatic mutations in Drosophila melanogaster induced by gamma-irradiation].

    PubMed

    Fedorov, V I; Pogodin, A S; Dubatolova, T D; Varlamov, A V; Leont'ev, K V; Khamoian, A G

    2001-01-01

    It was shown that the number of spontaneous and gamma-radiation-induced somatic mutations in wing cells of fruit flies (third instar larvae) exposed to laser irradiation of submillimeter range (lambda = 81.5 microns) was significantly lower than in control. Laser irradiation did not affect the number of recombinations. Exposure to laser radiation in the infrared range and electromagnetic waves of the millimeter range (lambda = 3.8 mm) enhanced the effect of gamma-irradiation.

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

    PubMed

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

    2013-11-15

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

  16. [Effects of 25 Gy gamma-ray irradiation on the expression of CD62p in manually enriched human platelets].

    PubMed

    Zhao, Lin-Na; Zhao, Hong-Sheng; Li, Jian-Bin; Shan, Hong; Han, Xiao-Gai; Jiao, Hong-Liang

    2010-04-01

    This study was purposed to investigate the effects of 25 Gy gamma-ray irradiation on the CD62p expression, platelet count and the mean platelet volume (MPV) of manually enriched platelet suspension in different time of shelf life at 22 degrees C. Each of 16 bags with plasma-rich platelet was divided into two bags, one of which was exposed to 25 Gy gamma-ray of 137Cs and the other ones was not exposed. 16 bags then were preserved for 72 hours according to AABB standards. The irradiated platelets were regarded as the observation group, and the other ones were regarded as the control group, the expression of p-selectin (CD62p) in the above 2 groups was detected by flow cytometry before irradiation and at 24, 72 hours after irradiation respectively; at the same time, the platelet count and MPV were assayed by using blood cell counter. The results showed that the expression level of CD62p on platelet in irradiated and control groups increased along with the prolonging of preservation time, the expression rate of CD62p on the platelets preserved for 24 hours was higher than that on fresh platelets with significant difference (p<0.05); the expression rate of CD62p on the platelets preserved for 72 hours obviously was enhanced as compared with platelets preserved for 24 hours (p<0.01). There were no significant differences in CD62p expression rate, platelet count and MPV between irradiated and control groups preserved for 24 and 72 hours (p>0.05), however the MPV of irradiated and control groups preserved for 72 hours was higher than that of fresh platelets (p<0.05). It is concluded that the gamma-ray irradiation does not affect the quantity and quality of platelets, but the preservation time for manually enriched platelet suspension should be shortened as far as possible.

  17. Response-surface models for deterministic effects of localized irradiation of the skin by discrete {beta}/{gamma} -emitting sources

    SciTech Connect

    Scott, B.R.

    1995-12-01

    Individuals who work at nuclear reactor facilities can be at risk for deterministic effects in the skin from exposure to discrete {Beta}- and {gamma}-emitting ({Beta}{gamma}E) sources (e.g., {Beta}{gamma}E hot particles) on the skin or clothing. Deterministic effects are non-cancer effects that have a threshold and increase in severity as dose increases (e.g., ulcer in skin). Hot {Beta}{gamma}E particles are {sup 60}Co- or nuclear fuel-derived particles with diameters > 10 {mu}m and < 3 mm and contain at least 3.7 kBq (0.1 {mu}Ci) of radioactivity. For such {Beta}{gamma}E sources on the skin, it is the beta component of the dose that is most important. To develop exposure limitation systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for evaluating the risk of deterministic effects of localized {Beta} irradiation of the skin. The purpose of this study was to develop dose-rate and irradiated-area dependent, response-surface models for evaluating risks of significant deterministic effects of localized irradiation of the skin by discrete {Beta}{gamma}E sources and to use modeling results to recommend approaches to limiting occupational exposure to such sources. The significance of the research results as follows: (1) response-surface models are now available for evaluating the risk of specific deterministic effects of localized irradiation of the skin; (2) modeling results have been used to recommend approaches to limiting occupational exposure of workers to {Beta} radiation from {Beta}{gamma}E sources on the skin or on clothing; and (3) the generic irradiated-volume, weighting-factor approach to limiting exposure can be applied to other organs including the eye, the ear, and organs of the respiratory or gastrointestinal tract and can be used for both deterministic and stochastic effects.

  18. Use of gamma-irradiation technology in combination with edible coating to produce shelf-stable foods

    NASA Astrophysics Data System (ADS)

    Ouattara, B.; Sabato, S. F.; Lacroix, M.

    2002-03-01

    This research was undertaken to determine the effectiveness of low-dose gamma-irradiation combined with edible coatings to produce shelf-stable foods. Three types of commercially distributed food products were investigated: precooked shrimps, ready to cook pizzas, and fresh strawberries. Samples were coated with various formulations of protein-based solutions and irradiated at total doses between 0 and 3 kGy. Samples were stored at 4°C and evaluated periodically for microbial growth. Sensorial analysis was also performed using a nine-point hedonic scale to evaluate the organoleptic characteristics (odor, taste and appearance). The results showed significant ( p⩽0.05) combined effect of gamma-irradiation and coating on microbial growth (APCs and Pseudomonas putida). The shelf-life extension periods ranged from 3 to 10 days for shrimps and from 7 to 20 days for pizzas, compared to uncoated/unirradiated products. No significant ( p>0.05) detrimental effect of gamma-irradiation on sensorial characteristics (odor, taste, appearance) was observed. In strawberries, coating with irradiated protein solutions resulted in significant reduction of the percentage of mold contamination.

  19. EPR study of free radicals in non- and gamma-irradiated nutritive supplements containing anthocyanins concentrate from lyophilized red wine

    NASA Astrophysics Data System (ADS)

    Mladenova, Ralitsa B.; Firzov, Cyril; Yordanov, Nicola D.

    2010-09-01

    Nutritive supplements Enoviton, Enoviton C and Enoviton CE containing standardized anthocyanins from lyophilized red wine, vitamins (some of them) and excipients were investigated by EPR spectrometry before and after gamma-irradiation. Non-irradiated samples exhibit one singlet line with g=2.0039±0.0002, most probably due to free radicals from anthocyanins. After irradiation with 10 kGy gamma-rays, tablets of Еnoviton, Еnoviton С and Еnoviton СЕ, all exhibit complex EPR signals centered at a g-value of g=2.0034. The EPR spectrum of irradiated Enoviton is different from that of Еnoviton С or Еnoviton СЕ due to the overlap of the spectra of microcrystalline cellulose and the background singlet spectrum present in all tablets with the EPR resonance due to irradiated ascorbic acid (in Еnoviton С and Еnoviton СЕ). Gamma-induced free radicals exhibit long time stability—for a six months period the intensity of central peak decrease with 30-40%.

  20. Effects of carotenoids on damage of biological lipids induced by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Saito, Takeshi; Fujii, Noriko

    2014-05-01

    Carotenoids are considered to be involved in the radioresistant mechanisms of radioresistant bacteria. In these bacterial cells, carotenoids are present in biological lipids, and therefore may be related to the radiation-induced damage of lipids. However, only limited data are available for the role of carotenoids in such damage. In this study, we irradiated an α-linolenic acid-benzene solution with gamma rays and analyzed the resulting oxidative degradation and peroxidation damage in the presence or absence of two typical carotenoids: β-carotene and astaxanthin. The analyses revealed that oxidative degradation and peroxidation of α-linolenic acid, as evaluated by the amount of malondialdehyde and conjugated diene formed, respectively, increased in a dose-dependent manner. Moreover, 8.5×10-3 M β-carotene inhibited gamma radiation-induced oxidative degradation of α-linolenic acid, whereas 5.0×10-5 and 5.0×10-6 M β-carotene, and 5.0×10-7 and 5.0×10-8 M astaxanthin promoted degradation. In contrast, neither β-carotene nor astaxanthin affected peroxidation of α-linolenic acid. These results suggest that an optimum concentration of carotenoids in radioresistant bacteria protects biological lipid structures from radiation-induced damage.