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In this study, Poly(vinyl alcohol)/cellulose nanofiber (PVA/CNF) hydrogels have been successfully prepared using γ-ray irradiation, annealing, and rehydration processes. In addition, the effects of CNF content and annealing methods on the hydrogel properties, including gel fraction, micromorphology, crystallinity, swelling behavior, and tensile and friction properties, are investigated. Consequently, the results show that at an absorbed dose of 30 kGy, the increase in CNF content increases the gel fraction, tensile strength, and elongation at break of irradiated PVA/CNF hydrogels, but decreases the water absorption. In addition, the cross-linking density of the PVA/CNF hydrogels is significantly increased at an annealing temperature of 80 °C, which leads to the transition of the cross-sectional micromorphology from porous networks to smooth planes. For the PVA/CNF hydrogel with a CNF content of 0.6%, the crystallinity increases from 19.9% to 25.8% after tensile annealing of 30% compared to the original composite hydrogel. The tensile strength is substantially increased from 65.5 kPa to 21.2 MPa, and the modulus of elasticity reaches 4.2 MPa. Furthermore, it shows an extremely low coefficient of friction (0.075), which suggests that it has the potential to be applied as a material for artificial joint cartilage. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ion chromatography was used to investigate the effects of γ-ray irradiation dose, vitamin C (VC) content and niacinamide content on nitrite degradation in aqueous solution and spiced donkey meat, and the volatile components of irradiated spiced donkey meat were analyzed by gas chromatography-ion mobility spectrometry. The results showed that γ-ray irradiation could effectively degrade nitrite in both aqueous solution and spiced donkey meat. A synergistic effect was observed when γ-ray irradiation and VC were used together. Nicotinamide had an inhibitory effect on the irradiation degradation of nitrite in aqueous solution, but had a synergistic effect on the irradiation degradation of nitrite in spiced donkey meat. Nitrite ions in aqueous solution were converted to nitrate ions by the irradiation. After 8 or 10 kGy irradiation, the contents of hexanal and heptanal increased, and donkey meat had an off-flavor. This study provides technical support and a theoretical basis for the degradation of nitrite in spiced donkey meat by γ-ray irradiation.

In this study, Poly(vinyl alcohol)/cellulose nanofiber (PVA/CNF) hydrogels have been successfully prepared using γ-ray irradiation, annealing, and rehydration processes. In addition, the effects of CNF content and annealing methods on the hydrogel properties, including gel fraction, micromorphology, crystallinity, swelling behavior, and tensile and friction properties, are investigated. Consequently, the results show that at an absorbed dose of 30 kGy, the increase in CNF content increases the gel fraction, tensile strength, and elongation at break of irradiated PVA/CNF hydrogels, but decreases the water absorption. In addition, the cross-linking density of the PVA/CNF hydrogels is significantly increased at an annealing temperature of 80 °C, which leads to the transition of the cross-sectional micromorphology from porous networks to smooth planes. For the PVA/CNF hydrogel with a CNF content of 0.6%, the crystallinity increases from 19.9% to 25.8% after tensile annealing of 30% compared to the original composite hydrogel. The tensile strength is substantially increased from 65.5 kPa to 21.2 MPa, and the modulus of elasticity reaches 4.2 MPa. Furthermore, it shows an extremely low coefficient of friction (0.075), which suggests that it has the potential to be applied as a material for artificial joint cartilage.

Simple Summary: Animal feeds contain a substantial number and diversity of microorganisms due to bacterial contamination during processing, transportation, and storage, and some of them have pathogenic potential. To test the effect of gamma (γ)-ray irradiation on the elimination of bacteria in different feeds, we treated fishmeal, feather meal, meat meal, soybean meal, and vitamin complexes with graded doses of γ-ray irradiation. We found that a dose of 6–9 kGy was sufficient to eliminate most of the bacteria in the investigated feed. We also found that fishmeal with a high bacterial load and Escherichia coli (E. coli) contamination induced an increased diarrhea index and impaired the growth performance of weaning piglets but that these effects were reduced by γ-ray irradiation treatment at 6 kGy. These findings demonstrate that γ-ray irradiation can be used to treat feeds with biosafety concerns. Animal feeds contain a substantial number and diversity of microorganisms, and some of them have pathogenic potential. The objectives of this study were to investigate the effects of different doses of gamma (γ)-ray irradiation on the bacteria count in different types of feed and then to test the effect of γ-ray-irradiation-treated fishmeal on the gut health and growth performance of weaning piglets. In trial 1, three fishmeal samples, two feather meal samples, three meat meal samples, three soybean meal samples, and three vitamin complexes were treated with γ-ray irradiation doses of 0, 3, 6, or 9 kGy. The 6 and 9 kGy doses eliminated most of the bacteria in the feed but also resulted in a loss of vitamin C and B1. In trial 2, 96 weaning piglets were fed one of the following three diets with eight replicates (pens) per group over a 14-day period: (1) the control diet—the basal diet supplemented with 6% fishmeal with a low bacteria count (40 CFU/g) and no E. coli; (2) the fishmeal-contaminated diet (FM-contaminated) diet—the basal diet supplemented with 6% fishmeal with a high bacteria count (91,500 CFU/g) and E. coli contamination; and (3) the irradiated fishmeal (irradiated FM) diet—the basal diet supplemented with γ-ray-irradiation-treated E. coli-contaminated fishmeal. The piglets that received the FM-contaminated diet had significantly lower average daily gain and a greater diarrhea index compared to those fed the control diet, whereas γ-ray irradiation treatment abrogated the negative effect of the E. coli-contaminated fishmeal. Collectively, γ-ray irradiation at a dose of 6–9 kGy was sufficient to eliminate the microorganisms in the feed, thereby benefitting the growth performance and gut health of the weaning piglets. [ABSTRACT FROM AUTHOR]

Chilled pigeon meat was irradiated with different doses of 60Co-γ rays, and the effect of irradiation on the quality and lipid oxidation of chilled pigeon meat was investigated through the determination of biochemical and physicochemical indexes, volatile flavor components and microstructure observation. The results showed that with an increase in irradiation dose, the a* value, total volatile basic nitrogen (TVB-N) value, juice loss percentage, peroxide value (POV), thiobarbituric acid reactive substances (TBARS) value and acid value increased significantly (P < 0.05), and total bacterial number (TBN), L* value, b* value and texture parameters decreased significantly (P < 0.05); the diameter of muscle fibers decreased significantly (P < 0.05) and the gap between muscle fibers increased; and the contents of total, saturated and monounsaturated fatty acids increased significantly (P < 0.05), while the contents of polyunsaturated fatty acids decreased significantly (P < 0.05), indicating that irradiation treatment can promote the oxidative hydrolysis of lipids into free fatty acids and the decomposition of polyunsaturated fatty acids in pigeon meat. A total of 73 volatile components belonging to 8 chemical classes were detected in pigeon meat. Among them, hydrocarbons and aldehydes were most abundant, indicating that lipid oxidation has an important impact on the flavor of irradiated pigeon meat. The results of this study can provide a theoretical basis for the application of irradiation in the processing of livestock and poultry meat.

To explore the effects of absorbed dose and particle size on enzymatic hydrolysis and fermentation of reed straws (Phragmites australias), the straws were irradiated with γ-ray irradiation at different doses (0-500 kGy) and then passed through different aperture sieves after mechanical grinding. The effects of absorbed doses and sieving aperture size on particle size distribution, comminution energy, main component content, enzymatic hydrolysis conversion rate, and ethanol conversion rate of cellulose were examined, and the optimal respective sieving aperture for reed straws with different absorbed doses were determined. The results showed that with decreasing sieve aperture size, reed straw quality decreased significantly and was negatively correlated with the absorbed dose; the comminution energy of reed straws decreased with increasing absorbed doses. With respect to consistent quality of sieved reed straws, the comminution energy increased significantly with decreasing sieving particle size. In reed straws with the same absorbed dose, the enzymatic hydrolysis conversion rate and ethanol conversion rate of cellulose increased with decreasing sieving aperture size. Compared with reed straws with particle size r ˂ 0.850 mm, the cellulose enzymatic hydrolysis conversion rates in reed straws with particle size r ˂ 0.180 mm increased by 129.20%, 85.98%, and 106.63% at absorbed doses of 0 kGy, 206 kGy, and 404 kGy, respectively, and cellulose ethanol conversion increased by 136.04%, 21.75%, and 4.39%, respectively. By compre- hensively comparing the increased ratios of comminution energy, cellulose enzymatic hydrolysis conversion rate, and cellulose ethanol conversion rate, the optimal sieving aperture of non-irradiated (0 kGy) reed straws was deter-mined to be 0.850 mm, and that of reed straws irradiated with 206 kGy or 404 kGy was determined to be 0.425 mm.

In this study, graphdiyne was prepared using a γ-irradiated N-doping photogram to transform two-dimensional graphdiyne into a one-dimensional tubular structure for use as substrate-supported iron nanoparticles for cathodic redox reaction (ORR) in fuel cells. Methods such as scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and isothermal nitrogen adsorption and other characterization methods were used to characterize and analyze the surface morphology, element composition, crystalline structure, and defect degree of the prepared composites. In the alkaline solution, the prepared catalyst was characterized by ORR performance, four-electron selectivity, kinetics and stability via cyclic voltammetry test, linear sweep voltammetry test and electrochemical AC impedance spectroscopy test. The results showed that after γ-ray irradiation, the nitrogen-doped graphite monoalkyne-loaded iron nanoparticle (NGY-Fe) catalyst had a larger specific surface area (411.3 m2/g) and a multilevel pore structure, which was conducive to the exposure of the active center. Moreover, the O2 permeation barrier was decreased, and the ORR activity of the NGY-Fe was significantly improved, especially in terms of the stability and methanol resistance, which were far superior to those of the commercially available commercial Pt/C catalysts.

γ-Irradiation and synchrotron-radiation-based X-ray absorption fine-structure (XAFS) spectroscopy have been used to induce structure disorder through the interaction of γ-rays (200 kGy) with fabricated Mn-doped ZnO nanoparticles (NPs) and then to examine thoroughly the resultant structural change. The extracted electronic/fine XAFS structural parameters reflect a compositional and γ-irradiation co-dependence. The average crystal structure of samples prepared by the sol-gel method was investigated by X-ray diffraction (XRD). A detailed structural XRD data analysis was carried out by applying a Rietveld refinement using the MAUD program. XAFS spectra were collected at the Zn K-edge (9659 eV) in transmission mode and at the Mn K-edge (6539 eV) in fluorescence mode. Direct evidence of the solubility of Mn ions in the ZnO structure was demonstrated by fitting the extended-XAFS (EXAFS) signal. Near-edge XAFS (XANES) analysis provided the oxidation states of Zn and Mn ions through fingerprint XANES spectra of the sample along with those of standard compounds. Linear combination fitting showed that the most fit chemical forms of Zn and Mn in the samples are ZnO and MnO, respectively. The oxidation states of both Zn and Mn XAFS absorbers were confirmed from pre-edge fitting. The results of the magnetic measurements were explained in light of the average and electronic/local structural information obtained from XRD, XANES and EXAFS techniques. The magnetic properties of the samples translate into an induced change in the average crystal and electronic/local structures upon Mn concentration change and γ-irradiation. XRD confirmed the successful preparation of hexagonal Mn-doped ZnO NPs with a crystallite size in the range 33–41 nm. Both XRD and EXAFS analysis detected a minor amount of Mn3O4 as a secondary phase. XANES and EXAFS provided information exploring the outstanding potential of the utilized protocol for detecting precisely the presence of the secondary phase of Mn3O4, which changes with Mn content (x). Mean-square relative displacement (σ2) values extracted from the EXAFS fitting were found to grow for Zn–Zn/Mn paths demonstrating the substitution of Mn/Zn into Zn crystal sites. The EXAFS analysis explains the reasons behind the enhancement in the magnetic properties and shows that the Mn doping content at x = 0.05 produces the most local atomic disorder in ZnO NPs. There is a strong harmony among the XRD, XANES, EXAFS and magnetization behavior of the Mn-doped ZnO NPs. Maximum magnetization was acquired at an Mn content of 0.05. γ-Ray-irradiated Zn1–xMnxO NPs are recommended as optimized candidates for showing the diversity of the applications.

Ionizing radiation damages DNA and may lead to the development of cancer. Irradiation also generates reactive oxygen species (ROS) which cause damage to various biological molecules. Relatively low dose‐rate irradiation causes less damage. However, the damage and its effects on cell fate are difficult to evaluate. To develop a method to analyze the damage and accompanying changes in physiology in cells irradiated by γ‐rays at a relatively low dose‐rate, we used the protein array technique to quantify marker proteins involved in the stress response and the regulation of cell growth and death. This method enabled efficient analyses of many replicates of experimental data on cell lysate samples. We detected relatively small changes in the levels of these proteins in the irradiated cells. Changes in protein levels suggested ROS production and DNA damage as well as cell cycle retardation and the progression of cellular senescence. Thus, our approach shows promise for analyzing the biological effects of relatively low dose‐rate irradiation. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Animal feeds contain a substantial number and diversity of microorganisms, and some of them have pathogenic potential. The objectives of this study were to investigate the effects of different doses of gamma (γ)-ray irradiation on the bacteria count in different types of feed and then to test the effect of γ-ray-irradiation-treated fishmeal on the gut health and growth performance of weaning piglets. In trial 1, three fishmeal samples, two feather meal samples, three meat meal samples, three soybean meal samples, and three vitamin complexes were treated with γ-ray irradiation doses of 0, 3, 6, or 9 kGy. The 6 and 9 kGy doses eliminated most of the bacteria in the feed but also resulted in a loss of vitamin C and B1. In trial 2, 96 weaning piglets were fed one of the following three diets with eight replicates (pens) per group over a 14-day period: (1) the control diet—the basal diet supplemented with 6% fishmeal with a low bacteria count (40 CFU/g) and no E. coli; (2) the fishmeal-contaminated diet (FM-contaminated) diet—the basal diet supplemented with 6% fishmeal with a high bacteria count (91,500 CFU/g) and E. coli contamination; and (3) the irradiated fishmeal (irradiated FM) diet—the basal diet supplemented with γ-ray-irradiation-treated E. coli-contaminated fishmeal. The piglets that received the FM-contaminated diet had significantly lower average daily gain and a greater diarrhea index compared to those fed the control diet, whereas γ-ray irradiation treatment abrogated the negative effect of the E. coli-contaminated fishmeal. Collectively, γ-ray irradiation at a dose of 6–9 kGy was sufficient to eliminate the microorganisms in the feed, thereby benefitting the growth performance and gut health of the weaning piglets.

The Ca-based organic framework (Ca-SINAP-1) loaded with silver was successfully prepared, which has a certain γ-ray irradiation resistance of 50 kGy. X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller specific surface area analysis, and pore volume analysis were used to characterize the sample and its Xe adsorption capacity. The results showed that loading of silver on the sample surface did not change the original structure of Ca-SINAP-1. However, the Xe uptake reached a maximum of 3.29 mmol/g and the Xe/Kr separation coefficient was 10.71 when silver loading was 0.93%. With increasing AgNO3 concentration in ethanol, the Xe adsorption quantity decreased because excess silver loading blocked the channels, and thus prevented Xe adsorption. The good irradiation resistance and high Xe/Kr selectivity make Ca-SINAP-1 a potential material for treating radioactive off-gas emitted from molten salt reactors.

The effects of γ-ray irradiation on the thermal stability and creep resistance of ultra-high molecular weight polyethylene (UHMWPE) were studied. First, UHMWPE powder was hot pressed into 1 mm thick sheets using a vulcanization molding machine. The chemical structure, thermal stability, microstructure, tensile properties, and creep properties of the irradiated plate samples were studied. The results demonstrated that, after γ-ray irradiation, the melting points, crystallinity, and thermal stability increased; the gel content increased to 89%; and the motility of molecular chains decreased. Compared with the creep resistance of the unirradiated sample, that of the irradiated sample increased by approximately 40%. In this study, the thermal stability and creep resistance of UHMWPE were significantly improved via the radiation cross-linking process, which provided a method for the preparation of UHMWPE materials with high creep resistance and high thermal stability.

During the long-term deep geological disposal of high-level radioactive waste, buffer materials, such as bentonite, in the waste repositories are irradiated with gamma (γ) rays, affecting their structural stability. Furthermore, bentonite colloids are formed owing to the erosion of bentonite particles by groundwater. However, the effects of prolonged irradiation on the stability of bentonite colloids and their interaction with radionuclides, which can affect the migration of the radionuclides, are yet to be elucidated. Herein, we investigated the stability of colloid prepared from irradiated bentonite with varying doses of γ rays and conducted static adsorption batch experiments to examine their U(VI) adsorption behavior. The results showed that the stability of bentonite colloids was affected by their concentration, storage time, pH, and temperature. An investigation into their polymerization kinetics revealed that the critical coagulation concentration of bentonite colloids decreased with increasing irradiation dose, indicating that the colloids formed from unirradiated bentonite were stable. Furthermore, the U(VI) adsorption capacity of bentonite colloids decreased with increasing irradiation dose. This study provides new insights into the formation and stability of colloids of buffer materials after their irradiation and is expected to contribute significantly to the study of the migration behavior of nuclides by colloidal carriers. [Display omitted] [ABSTRACT FROM AUTHOR]

γ-Irradiation and synchrotron-radiation-based X-ray absorption fine-structure (XAFS) spectroscopy have been used to induce structure disorder through the interaction of γ-rays (200 kGy) with fabricated Mn-doped ZnO nanoparticles (NPs) and then to examine thoroughly the resultant structural change. The extracted electronic/fine XAFS structural parameters reflect a compositional and γ-irradiation co-dependence. The average crystal structure of samples prepared by the sol-gel method was investigated by X-ray diffraction (XRD). A detailed structural XRD data analysis was carried out by applying a Rietveld refinement using the MAUD program. XAFS spectra were collected at the Zn K-edge (9659 eV) in transmission mode and at the Mn K-edge (6539 eV) in fluorescence mode. Direct evidence of the solubility of Mn ions in the ZnO structure was demonstrated by fitting the extended-XAFS (EXAFS) signal. Near-edge XAFS (XANES) analysis provided the oxidation states of Zn and Mn ions through fingerprint XANES spectra of the sample along with those of standard compounds. Linear combination fitting showed that the most fit chemical forms of Zn and Mn in the samples are ZnO and MnO, respectively. The oxidation states of both Zn and Mn XAFS absorbers were confirmed from pre-edge fitting. The results of the magnetic measurements were explained in light of the average and electronic/local structural information obtained from XRD, XANES and EXAFS techniques. The magnetic properties of the samples translate into an induced change in the average crystal and electronic/local structures upon Mn concentration change and γ-irradiation. XRD confirmed the successful preparation of hexagonal Mn-doped ZnO NPs with a crystallite size in the range 33-41 nm. Both XRD and EXAFS analysis detected a minor amount of Mn3O4 as a secondary phase. XANES and EXAFS provided information exploring the outstanding potential of the utilized protocol for detecting precisely the presence of the secondary phase of Mn3O4, which changes with Mn content (x). Mean-square relative displacement (σ2) values extracted from the EXAFS fitting were found to grow for Zn-Zn/Mn paths demonstrating the substitution of Mn/Zn into Zn crystal sites. The EXAFS analysis explains the reasons behind the enhancement in the magnetic properties and shows that the Mn doping content at x = 0.05 produces the most local atomic disorder in ZnO NPs. There is a strong harmony among the XRD, XANES, EXAFS and magnetization behavior of the Mn-doped ZnO NPs. Maximum magnetization was acquired at an Mn content of 0.05. γ-Ray-irradiated Zn1-xMnxO NPs are recommended as optimized candidates for showing the diversity of the applications. [ABSTRACT FROM AUTHOR]

Up to now, facile and pollution-free routes for catalyst preparation are in high demand. In this study, a green and cost-effective strategy was successfully developed to construct platinum/graphene aerogel (Pt/GA) nanocomposites by the co-reduction of graphene oxides (GO) and chloroplatinic acid (H2PtCl6·6H2O) with the assists of γ-ray irradiation in the absence of any other reductants. Characterization studies indicated that the energy of γ-ray irradiation and the hole scavenger isopropanol (IPA) played a vital role in forming small Pt nanoparticles with uniform size of ∼3 nm on the surface of graphene aerogel (GA). Furthermore, Pt/GA synthesized with a mass ratio of 2:1 (Pt/GA-2) exhibited a lowest activation energy value and outstanding catalytic properties for the reduction of 4-nitrophenol (4-NP). The excellent catalytic and cycling performance suggest that Pt/GA-2 catalyst has a promising prospect for the reduction of nitroaromatic compounds in wastewater treatment and other industrial applications.

The effects of γ-ray irradiation on the lipophilic and hydrophobic properties of two types of polypropylene (PP) foam materials were systematically studied. Isotactic polypropylene (iPP) and high-melt-strength polypropylene (HMSPP) sheets were prepared by hot pressing with a thickness of 1 mm, and then PP foams were prepared by supercritical CO2 batch foaming. Finally, the foamed samples were irradiated with γ-rays. The results showed that the melting points and crystallization temperatures of the two foams decreased after irradiation. The scanning electron microscope images showed that the cell walls of both PP foams appeared cracks and the roughness of the foam’s cross-section increased significantly. The water contact angle of iPP foam largely increased by 26.4%, and the contact angle of HMSPP foam increased from 135.2° to 141.8°, which almost reached the super-hydrophobic level. The enhanced roughness increased the hydrophilic defects and the droplet adhesion resistance. Moreover, the appearance of the cracks in the cell walls increased the connectivity between cells, which largely increased the foam oil absorption permeability and the oil absorption quantity. This study provides a method for preparing lipophilic and hydrophobic foam.

The serious damage caused to 3D braided carbon fiber (CF)/epoxy (EP) composites in high-energy irradiation environments is a pressing research topic that has not yet been reported. This study analyzed the γ-irradiation multi-scale damage of the matrix, interfaces, and near-interface regions in 3D braided CF/EP composites with three different braiding angles (18°, 28°, 38°) at atomic, microscopic, and macroscopic scales. The molecular structure and atomic charge information alterations of epoxy matrix were characterized using soft X-ray absorption spectroscopy (sXAS). When the irradiation dose reached 1000 KGy, the compressive strength of composites decreased by 20.88 %, 18.07 %, and 16.60 %, respectively, with an increase in the braiding angle. Micro-CT observation, along with statistical computing, confirmed that irradiation causes interface damage and increases the defect volume of 3D braided composites. Nanoindentation was used to compare the modulus of carbon fiber, interface, near-interface regions and matrix in irradiated composites and the function of CF/resin interface as an irradiation defect capture site in the irradiation resistance of resin-matrix composites has been newly established. In addition, the mechanism behind the effect of braiding angle on macroscopic properties was also analyzed. [Display omitted] • The braided structures exhibited varying responses to irradiation, with 3D-38° showing the highest performance retention. • Soft X-ray absorption spectrometry was developed to characterize the valence changes of oxygen and carbon in irradiated resin. • Interface as an irradiation defect capture site consumes most of the energy and reduces the damage of resin near the interface. [ABSTRACT FROM AUTHOR]

In order to explore the scavenging ability of free radicals in polymers and the derivation mechanism with the different influence of the composition and various structure of nanomaterials, two-dimensional graphene oxide, one-dimensional carbon nanotubes and zero-dimensional carbon black in carbon nanomaterials, and halloysite nanotubes in silicate nanomaterials were selected to carry out a task. The results manifest that the content of free radicals produced by γ-ray irradiation in epoxy resin reduced because of the introduction nanoparticle. Among them, the epoxy resin reinforced by graphene oxide has the least free radical, followed by carbon nanotubes, halloysite nanotubes and carbon black, respectively. The analysis shows that the free radical scavenging capability was significantly different in variety types of nanomaterials. The free radical scavenging ability of carbon nanomaterials is ascribed to its well-organized honeycomb lattice, which is different from the fact that silicate nanomaterials is attributed to its electron acceptor sites. Meanwhile, the stable electron cloud was formed in the carbon nanomaterials, which is more conducive to eliminate the free radicals. The addition of nanomaterials decreases the number of free radicals in the resin, and correspondingly weakens the damage of free radicals for the resin, resulting in improving the thermal stability and mechanical properties of the epoxy resin.

BackgroundCyclic olefin copolymer (COC), synthesized by catalytic copolymerization of ethylene and norbornene, can be applied in medical devices and drug packaging, owing to its many outstanding properties such as good light transmittance, water vapor barrier and biocompatibility. When this type of medical devices or drug package is sterilized by high energy irradiation, COC will inevitably undergo changes such as radiation scission, oxidation, discoloration and so on. It is of great significance to explain the performance change of COC from the free radical reaction initiated by ionization radiation for the radiation sterilization application of COC medical supplies.PurposeThis study aims to investigate radiation effect of COC in the dose range of radiation sterilization.MethodsEffects of γ-rays on chemical structure, free radical, glass transition temperature, thermal stability, molecular weight distribution, surface properties and melt index of the irradiated COC with the sterilization dose were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible absorption spectroscopy (UV-vas), electron spin resonance spectroscopy (ESRS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), water contact angle (WCA) and melt mass-flow rate measurement.ResultsThe concentration of free radicals produced by COC irradiation in air increases linearly with the increase of absorbed dose. With the increase of absorbed dose, radiation degradation is dominant, hence the average molecular weight of the radiation oxidation products include carbonyl and hydroxyl compounds decreases, and the surface hydrophilicity is enhanced whilst the melt index is increased.ConclusionsThe molecular chain breakage caused by radiation and the reaction between free radicals and oxygen are the main causes of COC degradation.

BackgroundThe adsorption and separation of Xenon (Xe) / Krypton (Kr) has received increasing attention due to the concern of reprocessing radioactive isotopes of Xe and Kr from off-gas of used nuclear fuel as well as the commercial value of high purity Xe gas. At present, the separation of Xe/Kr is mainly through cryogenic distillation, which is energy and capital intensive. Porous materials such as metal-organic frameworks (MOFs) have shown the ability to selectively adsorb xenon and krypton at relative high temperature, hence are expected to replace cryogenic distillation to achieve low-cost Xe/Kr separation.PurposeThis study aims to investigate the gamma radiation stability of three MOFs (Co/DOBDC, Ni/DOBDC, Co3(HCOO)6) used for Xe and Kr adsorption separation.MethodsFirst of all, three MOFs, i.e., Co/DOBDC, Ni/DOBDC, and Co3(HCOO)6, were synthesized and activated according to the preparation methods in the published literature, and the adsorption isotherms of Xe and Kr in three MOFs samples were measured by using physical adsorption instrument with a specially designed water circulating system to maintain a constant temperature (273 K). Then, these samples were irradiated with γ-ray (1.322 MeV) at a gamma dose rate of 0~1 kGy·h-1 at ambient temperature. Samples' properties, such as Henry constant, Henry selectivity and ideal adsorbed solution theory (IAST) selectivity of Xe/Kr, before and after irradiation, were characterized by X-ray diffraction (XRD) patterns and N2 adsorption measurements. Finally, the γ-ray radiation stability of Co/DOBDC, Ni/DOBDC and Co3(HCOO)6 were studied, and the pore properties (specific surface area and pore volume) before and after irradiation were compared.Results & ConclusionsExperimental results from the observed single-component Xe and Kr isotherms, Henry's constants, Henry's constant ratio and IAST selectivity of the sample, show that Co/DOBDC and Ni/DOBDC as adsorbents have the potential to adsorb and storage high concentration Xe whilst Co3(HCOO)6 has the potential for adsorption separation of Xe and Kr in low concentration. Radiation resistance test results show that the pore properties of Co/DOBDC and Ni/DOBDC change significantly after different doses of γ-ray irradiation, and the change degree of pore properties of Co/DOBDC is large than that of Ni/DOBDC whilst the pore properties of Co3(HCOO)6 basically do not change after γ-ray radiation at a total dose of 9 kGy, indicating that Co3(HCOO)6 can be considered as a potential adsorbent for Xe/Kr separation under radioactive conditions.

Aging is characterized by a progressive deterioration in metabolic functions. The present study aimed to investigate the antagonistic effects of ginsenoside Rg1 (Rg1) on the γ-ray irradiation-induced aging of mixed hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs). C57BL/6 mice were divided into a control group, a γ-ray irradiation group that served as an aging mouse model, and an Rg1 group. The Rg1 group was treated with Rg1 at dosage of 20 mg/kg/day for 7 days prior to γ-ray irradiation. The aging mouse model was established by exposing the mice to 6.5-Gy γ-ray total-body irradiation. Stem cell antigen 1 positive (Sca-1+) HSC/HPCs isolated from the mice were examined using a senescence-associated β-galactosidase (SA-β-Gal) staining assay. The cell cycle of the HSC/HPCs was examined using flow cytometry. A mixed hematopoietic progenitor cell colony-forming unit (CFU-mix) assay was also conducted. The mRNA and protein expression levels of sirtuin 1 (SIRT1), SIRT3, forkhead box O3 (FOXO3) and superoxide dismutase (SOD2) were evaluated using western blot and reverse transcription-quantitative PCR assays. The results indicated that Rg1 treatment significantly increased white blood cell, red blood cell and platelet counts in peripheral blood compared with those in the γ-ray irradiation group (P<0.05). However, Rg1 significantly attenuated the senescence of Sca-1+ HSC/HPCs in the γ-ray irradiation aging mice model. The proportion of SA-β-Gal stained HSC/HPCs was significantly decreased and CFU-Mix counts were significantly increased in the Rg1 group compared with the γ-ray irradiation group (P<0.05). Rg1 significantly increased the mRNA and protein levels of SIRT1, SIRT3, FOXO3 and SOD2 in the Sca-1+ HSC/HPCs compared with those in the γ-ray irradiation group (P<0.05). The percentage of Sca-1+ HSC/HPCs arrested at the G1 phase in the Rg1 group was significantly decreased compared with that in the γ-ray irradiation group (P<0.05). In conclusion, the present study indicates that Rg1 exerts anti-aging effects via the regulation of SIRT1-FOXO3 and SIRT3-SOD2 signaling pathways, and triggering the progression of Sca-1+ HSC/HPCs from the G1 phase to the S phase in γ-ray irradiation-induced aging mice. [ABSTRACT FROM AUTHOR]

In this article, we demonstrate that a physics-based compact model can facilitate to analyze the reliability using an example of γ-ray induced instability in AlGaN/GaN HEMTs. First, the typical AlGaN/GaN HEMTs are subjected to the cumulative γ-ray irradiation, exhibiting the drain current (ID) increase. In order to further elucidation, the root cause, the compact model is implemented and calibrated with the pristine case. Then, ID – VG and ID – VD characteristics subjected to the γ-ray irradiation are fitted with the compact model. The extracted μ and Rc are consistent with the results obtained by the Hall measurement and circular transmission line measurement (C-TLM). By comparing the fitted curves with considering: 1) fitted μ (Rc is fixed as the pristine case) and 2) fitted Rc (μ is fixed as the pristine case), the shift of μ is identified as the root cause leading to the ID increase because of the better fitting results. Therefore, with the assistance of the physics-based compact model, the shift of the parameter can be further analyzed to understand the origin of the instability. [ABSTRACT FROM AUTHOR]

Intensive study on structure transformation of muscovite single crystal under high-dose γ-ray irradiation is essential for its use in irradiation detection and also beneficial for mechanism cognition on defect formation within a matrix of clay used in the disposal of high-level radioactive waste (HLRW). In this work, muscovite single crystal was irradiated with Co-60 γ ray in air at a dose rate of 54 Gy min−1 with doses of 0–1000 kGy. Then, structure transformation and mechanism were explored by Raman spectrum, Fourier-transform infrared spectrum, X-ray diffraction, thermogravimetric analysis, CA, scanning electron microscope and atomic force microscopy. The main results show that variations in the chemical/crystalline structure are dose-dependent. Low-dose irradiation sufficiently destroyed the structure, removing Si–OH, thus declining hydrophilicity. With dose increase up to 100 kGy, CA increased from 20° to 40°. Except for hydrophilicity variation, shrink occurred in the (004) lattice plane which later recovered; the variation range at 500 kGy irradiation was 0.5% close to 0.02 Å. The main mechanisms involved were framework break and H2O radiolysis. Framework break results in Si–OH removal and H2O radiolysis results in extra OH introduction. The extra introduced OH probably results in Si–OH bond regeneration, lattice plane shrink and recovered surface hydrophilicity. The importance of framework break and H2O radiolysis on structure transformation is dose-dependence. At low doses, framework break seems more important while at high doses H2O radiolysis is important. Generally, variations in the chemical structure and surface property are nonlinear and less at high doses. This indicates using the chemical structure or surface property variation to describe irradiation is correct at low doses but not at high doses. This finding is meaningful for realizing whether muscovite is suitable for detecting high-dose irradiation or not, and mechanism exploration is efficient for identifying the procedure for defect formation within the matrix of clay used in disposal HLRW in practice.

Abstract In developing high-performance electrode materials for ion batteries, manifold methods to assemble definite structures of graphene-SnO x composite anodes are presented. Here we have firstly put forward an efficient strategy based on fortissimo penetration from γ-ray irradiation to assemble graphene and Sn/SnO 2 composite, which is formed by a large-scale and simple synthesis method. And uniform SnO 2 and Sn nanoparticles sandwiched between graphene sheets (sandwich-like Sn/SnO 2 @ graphene composite) are fabricated due to the synergism of interlamellar limitation of graphene oxide and ultra-strong penetration and high energy of γ-ray, which help to improve conductivity of Sn/SnO 2 and can prevent Sn/SnO 2 agglomeration and volume expansion due to graphene sheets buffed. High initial capacity about 2970.3 mAh g−1 and stable cycle performance are exhibited. This facile method has potential prospects to offer an attractive alternative approach for preparation of metal nanoparticles/graphene composite as high performance electrodes for Li/Na-ion batteries. Highlights • A strategy on γ-ray irradiation to assemble anode material is presented. • The formation cause is about interlamellar limitation of GO and penetration of γ-ray. • Sn/SnO 2 @graphene composite with sandwich-like structure is formed. • High initial capacity about 2970.3 mAh g−1 and stable cycle performance are obtained. [ABSTRACT FROM AUTHOR]

Ionizing radiation induces biological/physiological changes and affects commensal microbes, but few studies have examined the relationship between the physiological changes induced by irradiation and commensal microbes. This study investigated the role of commensal microbes in the γ-ray irradiation-induced physiological changes in Drosophila melanogaster. The bacterial load was increased in 5 Gy irradiated flies, but irradiation decreased the number of operational taxonomic units. The mean lifespan of conventional flies showed no significant change by irradiation, whereas that of axenic flies was negatively correlated with the radiation dose. γ-Ray irradiation did not change the average number of eggs in both conventional and axenic flies. Locomotion of conventional flies was decreased after 5 Gy radiation exposure, whereas no significant change in locomotion activity was detected in axenic flies after irradiation. γ-Ray irradiation increased the generation of reactive oxygen species in both conventional and axenic flies, but the increase was higher in axenic flies. Similarly, the amounts of mitochondria were increased in irradiated axenic flies but not in conventional flies. These results suggest that axenic flies are more sensitive in their mitochondrial responses to radiation than conventional flies, and increased sensitivity leads to a reduced lifespan and other physiological changes in axenic flies.

In this paper, chitosan (CS)/graphene oxide (GO) composite films were prepared, and the effect of γ-ray irradiation on the properties of composite films was investigated. The irradiation crosslinking reaction occurred in composite films with the existence of acetic acid, and the properties changed upon the various irradiation dose. The swelling degree of the composite film with 0 wt % GO decreased with the increasing of the irradiation dose, but the swelling degree of which with GO increased instead. The thermal stability increased with the increasing of the irradiation dose, but the effect of the irradiation on the thermal stability weakened as the increasing of the content of GO, due to the enhanced irradiation resistance performance. The tensile strength increased firstly and decreased subsequently with the increasing of the irradiation dose and the content of GO. Composite films showed the enhanced antibacterial activity against Bacillus subtilis, compared to Escherichia coli and Staphylococcus aureus. The antibacterial activity weakened with the increasing of the content of GO. The antibacterial activity was relatively stronger when the irradiation dose was 20 KGy. In addition, the structural, crystal, and morphological properties of composite films were characterized by FT-IR, XRD, and SEM. It is worth noting that the GO was pre-functionalized via KH560 for the better compatibility with CS matrix. [ABSTRACT FROM AUTHOR]

Polyethersulfone (PES) and monomer methacrylic acid (MAA) were chosen to synthesize the grafted polymer PES-g-PMAA by simultaneous γ-ray irradiation in homogenous phase. Membranes prepared from pristine PES and PES-g-PMAA with different degrees of grafting (DGs), have been obtained. The kinetics of grafting reaction and the DG values were studied through sulphur elemental analysis. The morphology study of the membranes showed formation of sponge-like structure in the sub-layer of membrane, along with grafting PMAA onto the PES chains. By ultrafiltration experiments, a regular pH-dependent permeability and thermal-dependent permeability of PES-g-PMAA membranes was demonstrated through introduction of PMAA onto the PES which reduced the water flux of the membranes. The pH-dependent permeability could be attributed to pH-sensitive reconfiguration of PMAA molecule chains on the surface of membrane pore, while thermal-dependent permeability might be caused by better thermal-sensibility of PMAA chains inside the membrane. [ABSTRACT FROM AUTHOR]

The effect of γ-ray irradiation on the surface plasmon resonance (SPR) sensing capability of refractive index (n = 1.418–1.448) of the silica glass optical fiber comprised of germano-silicate glass cladding embedded with Au nano-particles (NPs) was investigated. As the γ-ray irradiation increased from 1 h to 3 h with the dose rate of 1190 Gy/h, the morphology of the Au NPs and the SPR spectrum were found to change. The average diameter of Au NPs increased with the aspect ratio from 1 to 2, and the nano-particles became grown to the clusters. The SPR band wavelength shifted towards a longer wavelength with the increase of total dose of γ-ray irradiation regardless of the corresponding refractive indices. The SPR sensitivities (wavelength/refractive index unit, nm/RIU) also increased from 407 nm/RIU to 3553 nm/RIU, 1483 nm/RIU, and 2335 nm/RIU after the γ-ray irradiation at a total dose of 1190 Gy, 2380 Gy, and 3570 Gy, respectively.

Nanostructured MgFeO magnetic photocatalysts are facilely synthesized by Co γ-ray irradiation assisted polyacrylamide gel route. The influence of different irradiation doses on the morphologies, phase purity, energy bandgap, magnetic properties and photocatalytic activity of the as-prepared MgFeO nanoparticles were studied. The experimental results demonstrate that the phase purity, particle size, morphology, energy bandgap, magnetic properties and photocatalytic activity of MgFeO nanoparticles can be manipulated by the different irradiation doses. In particular, γ-ray irradiation improves the photocatalytic activity of MgFeO nanoparticles significantly. These MgFeO nanoparticles showed high efficiency for the degradation of methylene blue with simulated sunlight irradiation. These results bring up new ideas for the design of nanostructured MgFeO magnetic photocatalysts with tuned magnetic properties and photocatalytic activity through a Co γ-ray irradiation assisted polyacrylamide gel route. Graphical Abstract: Schematic representation of the polymerization reaction for MgFeO nanoparticle synthesis, starting from acrylamide and bis-acrylamide (left). Mg-ferrite magnetic photocatalysts were synthesized by γ-ray irradiated assisted polyacrylamide gel route. Optimized utilization of irradiation dose, and sintering temperature allowed the formation of Mg-ferrite nanoparticles with a narrow size distribution. In particular, γ-ray irradiation improves the magnetic properties and photocatalytic activity of MgFeO magnetic photocatalysts significantly. This MgFeO nanoparticles showed high efficiency for the degradation of methylene blue (MB) with simulated sunlight irradiation. [ABSTRACT FROM AUTHOR]

γ-Ray irradiation is used for the synthesis of silver–Polystyrene polyvinyl pyrrolidone nanocomposite microspheres with a controlled shape, size, and functional properties. A monodispersed polystyrene microsphere was synthesized using dispersion polymerization induced by γ-ray irradiation. A polystyrene microsphere surface was used to attract Silver (Ag) nanoparticles in which it is created on it via the continuous reduction of Ag + by γ-ray irradiation. Transmission Electron Microscopy, X-ray Diffraction Analysis, Ultraviolet–Visible Absorption, Thermal Gravimetric Analysis and Fourier Transform Infrared Spectroscopy are used for characterization of the final product. The discussion focuses on the physical–chemical aspects of the method. Special attention is paid to the preparation of nanocomposites with individual (non-aggregated) nanoparticles with a narrow size distribution and versatile morphologies, including the design of nanoparticles and nanocomposites that can perform multifunctional purposes. The focus was also on the problem of the spatial arrangement of nanoparticles and the elucidation of the role of polymers using this method. The synergistic role of the ingredients on the performance of nanocomposites was also discussed. [ABSTRACT FROM AUTHOR]

Cosmic radiation has always been the most obvious barrier to planetary travels, especially in long-duration deep space exploration missions. Therefore, the reliability of satellite materials and the requirements of satellite miniaturization have received considerable attention. In this paper, the effect of γ-ray irradiation on the reliability of Sn50Pb49Sb1/Cu solder joints was investigated. It was found that the influence of γ-ray irradiation on the thickness and morphology of the intermetallic compound layer in Sn50Pb49Sb1/Cu was not obvious. However, the formation and growth of micro-voids and micro-cracks was observed in Pb-based solid solutions. Due to the Compton effect, the γ-ray photon could knock the electron out of its orbit, which created the energetic electron. The accumulation of dislocated atoms and lattice vacancies generated by energetic electrons could be the main factor that caused the formation of micro-voids and micro-cracks. The pull force of Sn50Pb49Sb1/Cu solder joints was reduced by 22% after being irradiated at the dose rate of 0.25 Gy(Si)/s for 960 h. Fractographic analysis showed that after irradiation, the fracture type of solder joints was still ductile but the ductility of the solder joints decreased with slightly inconspicuous dimples.

The radial structural heterogeneity of thermally-stabilized polyacrylonitrile (PAN) fiber is considered to be a limiting factor affecting the mechanical properties of the resulting carbon fibers. In this study, we demonstrate that a low-dose (60 kGy) γ-ray irradiation pretreatment can effectively mitigate the radial structural heterogeneity of PAN fibers after thermal stabilization. The characterization results indicate that low-dose γ-ray irradiation only affects the physical structure of PAN through decreasing its crystalline size and crystallinity, rather than inducing chemical cross-linking and/or intramolecular cyclization. It is proposed that an increased amorphous region in PAN fibers prompted by low-dose γ-ray irradiation can facilitate oxygen diffusion from skin to core during stabilization, which results in the increased structural homogeneity of stabilized PAN fibers.

In this paper, chitosan (CS)/graphene oxide (GO) composite films were prepared, and the effect of γ-ray irradiation on the properties of composite films was investigated. The irradiation crosslinking reaction occurred in composite films with the existence of acetic acid, and the properties changed upon the various irradiation dose. The swelling degree of the composite film with 0 wt % GO decreased with the increasing of the irradiation dose, but the swelling degree of which with GO increased instead. The thermal stability increased with the increasing of the irradiation dose, but the effect of the irradiation on the thermal stability weakened as the increasing of the content of GO, due to the enhanced irradiation resistance performance. The tensile strength increased firstly and decreased subsequently with the increasing of the irradiation dose and the content of GO. Composite films showed the enhanced antibacterial activity against Bacillus subtilis, compared to Escherichia coli and Staphylococcus aureus. The antibacterial activity weakened with the increasing of the content of GO. The antibacterial activity was relatively stronger when the irradiation dose was 20 KGy. In addition, the structural, crystal, and morphological properties of composite films were characterized by FT-IR, XRD, and SEM. It is worth noting that the GO was pre-functionalized via KH560 for the better compatibility with CS matrix.

In the present study the bulk etch rate, the bulk activation energy, the track density and the degree of crystallinity percentage have been examined for gamma irradiated samples with 60Co source at doses ranging from 0 to 200 kGy. After gamma irradiation the samples were exposed to zirconium sand to collect α-particle tracks. Samples were etched at 60, 65, 70, 75 and 80°C in 6.25 N NaOH solution for 4 h. Results indicated that, the bulk etch rate increases with the increase of gamma absorbed dose at different etching temperatures. The bulk activation energy and the track density decreased with the increase of the gamma absorbed dose. The degree of crystallinity percentage for un-etched and etched samples also has been studied for different gamma doses. The increase in bulk etch rate and the decrease in both of bulk activation energy and track density with increase in the gamma dose may be due to the degradation in CR-39 polymeric material. [ABSTRACT FROM AUTHOR]

We investigated changes in the physical and chemical properties of rapeseed straw after treatment with different doses of 60 Co γ-irradiation (0 kGy-1200 kGy). Raman spectra, electron spin resonance (ESR), and nuclear magnetic resonance (NMR) analyses of the pretreated samples showed that the irradiation partially destroyed the intra- or intermolecular structure of rapeseed straw. Particle size distribution and specific surface area analyses suggested that irradiation decreased the particle size, narrowed the distribution range, and increased the specific surface area. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) curves showed that increasing the irradiated dose decreased the thermal stability of the treated rapeseed straw and increased the reactivity. Elemental analyses suggested that the oxygen content slightly increased, suggesting that oxygen in the air may be involved in the reaction. These results demonstrate that γ-irradiation can induce a series of changes in the physical and chemical properties of rapeseed straw. [ABSTRACT FROM AUTHOR]

60Co γ-ray irradiation-initiated reversible addition–fragmentation chain transfer (RAFT) polymerization at room temperature with 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the chain transfer agent was first applied to acrylonitrile (AN) polymerization, providing a “green” platform for preparing polyacrylonitrile (PAN)-based carbon fibers using an environment-friendly energy source. Various effects of dose rate, molar ratio of the monomer to the chain transfer agent, monomer concentration and reaction time on the AN polymerization behaviors were performed to improve the controllability of molecular the weight and molecular weight distribution of the obtained PAN. The feature of the controlled polymerization was proven by the first-order kinetics, linear increase of the molecular weight with the monomer conversion and a successful chain-extension experiment. The molecular weight and molecular weight distribution of PAN were characterized by size exclusion chromatography (SEC). 1H NMR and Matrix assisted laser desorption ionization/time of flight mass spectra (MALDI-TOF-MS) confirmed the chain-end functionality of PAN, which also was supported by the successful chain-extension experiments of original PANs with acrylonitrile and styrene as the second monomers respectively.

Highlights: [•] Abrogation of XRCC 1 could increase the sensitivity of γ-ray in HepG2 cells. [•] The enhanced sensitivity of γ-ray could be attributed to the increased SSB and DSB. [•] Increasing cell cycle arrest lead to enhance the irradiation sensitivity. [•] DNA-PKcs and gadd153 expression were contributed at least in part to these effects of irradiation sensitivity. [ABSTRACT FROM AUTHOR]

Abstract: Vanadium, an essential micronutrient, has been implicated in controlling diabetes and carcinogenesis and in impeding reactive oxygen species (ROS) generation. γ-ray irradiation triggers DNA damage by inducing ROS production and causes diminution in radiosensitive immunocytes. In this study, we elucidate the immune activation capacities of Jeju water containing vanadium on immunosuppression caused by γ-ray irradiation, and identify its mechanism using various low doses of NaVO3. We examined the intracellular ROS generation, DNA damage, cell proliferation, population of splenocytes, and cytokine/antibody profiles in irradiated mice drinking Jeju water for 180days and in non-irradiated and in irradiated splenocytes both of which were treated with NaVO3. Both Jeju water and 0.245μM NaVO3 attenuated the intracellular ROS generation and DNA damage in splenocytes against γ-ray irradiation. Splenocytes were significantly proliferated by the long-term intake of Jeju water and by 0.245μM NaVO3 treatment, and the expansion of B cells accounted for the increased number of splenocytes. Also, 0.245μM NaVO3 treatment showed the potency to amplify the production of IFN-γ and total IgG in irradiated splenocytes, which correlated with the expansion of B cells. Collectively, Jeju water containing vanadium possesses the immune activation property against damages caused by γ-irradiation. [Copyright &y& Elsevier]

Abstract: In the present study, chitosan had been utilized as a “green” stabilizing agent for the synthesis of spherical silver nanoparticles in the range of 5–30nm depending on the percentage of chitosan used (0.1, 0.5, 1.0 and 2.0wt%) under γ-irradiation. X-ray diffractometer identified the nanoparticles as pure silver having face-centered cubic phase. Ultraviolet–visible spectra exhibited the influence of γ-irradiation total absorbed dose and chitosan concentration on the yield of silver nanoparticles. The antibacterial properties of the silver nanoparticles were tested against Methicillin-resistant Staphylococcus aureus (MRSA) (gram-positive) and Aeromonas hydrophila (gram-negative) bacteria. This work provides a simple and “green” method for the synthesis of highly stable silver nanoparticles in aqueous solution with good antibacterial property. [Copyright &y& Elsevier]

Dried herbal samples consisting of root, rhizome, cortex, fruit, peel, flower, spike, ramulus, folium, and whole plant of 20 different medicinal herbs were investigated using pulsed photostimulated luminescence (PPSL), thermoluminescence (TL), and electron spin resonance spectroscopy (ESR) to identify γ-ray irradiation treatment. Samples were irradiated at 0–50 kGy using a 60Co irradiator. PPSL measurement was applied as a rapid screening method. Control samples of 19 different herbs had photon counts less than the lower threshold value (700 counts 60 s−1). The photon counts of non-irradiated clematidis radix and irradiated evodia and gardenia fruits were between the lower and upper threshold values (700–5,000 counts 60 s−1). TL ratios, i.e., integrated areas of the first glow (TL1)/the second glow (TL2), were found to be less than 0.1 in all non-irradiated samples and higher than 0.1 in irradiated ones providing definite proof of radiation treatment. ESR spectroscopy was applied as an alternative rapid method. In most of the irradiated samples, mainly radiation-induced cellulosic, sugar, and relatively complicated carbohydrate radical ESR signals were detected. No radiation-specific ESR signal, except one intense singlet, was observed for irradiated scrophularia and scutellaria root and artemisiae argyi folium. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Nickel selenide nanoparticles were synthesized using γ-ray irradiation in the presence of natural polymer, chitosan as capping agent. Chitosan is the deacetylated product of chitin, the second most abundant organic resources after cellulose. The nanoparticles were produced using nickel acetate and selenium dioxide and the as-prepared chitosan stabilized nanoparticles were soluble and stable in aqueous solution. The morphology and structure of the nickel selenide nanoparticles were characterized using transmission electron microscope (TEM) and X-ray diffraction (XRD). Optical properties of the nanoparticles were characterized by UV–Visible spectrophotometer and photoluminescent spectroscopy. The XRD result shows that the nickel selenide conformed to Ni3Se2 with crystal structure of rhombohedral. The absorption spectrum of the Ni3Se2 nanoparticles covered from around 300–600nm which makes it a potential photovoltaic and optoelectronic device material. In this report, γ-ray irradiation provided a “green”, simple and clean route for the synthesis of chitosan stabilized Ni3Se2 nanoparticles. The size and size distribution of the nickel selenide nanoparticles were influenced by the concentration of chitosan and absorbed dose of γ-ray irradiation. [Copyright &y& Elsevier]

Abstract: Ag nanoparticles were directly deposited on anatase TiO2 clusters via a two-step route, which included a 60Co γ-ray irradiation method after acidic peptization of amorphous TiO2. The as-prepared TiO2 clusters could act as effective stabilizers to immobilize Ag nanoparticles reduced in the process of γ-radiolysis. The composite consisted of TiO2 particles with about 5nm and Ag particles with less than 2nm in diameter, and it was highly dispersed in aqueous solution and thermodynamically stable. After calcining Ag/TiO2 composites in flowing N2 gas, a largely enhanced photocatalytic activity was verified by photodegradation of methylene blue (MB). [Copyright &y& Elsevier]

Abstract: We explored the synthesis of Ag/SiO2 catalysts via γ-ray irradiation at room temperature. AgNO3/SiO2 prepared by the conventional incipient wetness impregnation method was employed as the precursor. Ag/SiO2 catalyst prepared by calcining AgNO3/SiO2 at 500°C was also prepared for comparison. The Ag/SiO2 catalysts were characterized with X-ray diffraction, X-ray photoelectron spectroscopy, and diffuse reflectance UV–vis spectrum, and their catalytic activities towards CO oxidation were also tested. γ-Ray irradiation successfully reduced Ag+ anchored on SiO2 into silver nanoparticles at room temperature. Existence of excess water during the γ-ray irradiation led to the formation of larger silver nanoparticles. These catalysts behaved differently in CO catalytic oxidation. Compared with Ag/SiO2 prepared by calcination that showed a certain low temperature catalytic activity but poor stability, Ag/SiO2 prepared by room temperature γ-ray irradiation showed an inferior low temperature catalytic activity and a better stability. The different catalytic behavior is associated with the various crystalline sizes of silver nanoparticles in Ag/SiO2 prepared by different methods. [Copyright &y& Elsevier]

The radiation-induced degradation of acetochlor was investigated in this work. In a mixed solvent composed of acetonitrile and water at a ratio of 20/80 in volume, the acetochlor degradation rate was proportional to the radiation dose rate and acetochlor concentration. The acetochlor degradation efficiency was higher under alkali conditions and lower under acidic conditions. The contribution to the acetochlor degradation by the radicals was in the order of: eaq- > •OH > H•. The quantum efficiency ratios of OH, eaq- and H• for the degradation of acetochlor were calculated as 1:3:1. [Copyright &y& Elsevier]