White spot syndrome virus inactivation study by using gamma irradiation

The present study was conducted to investigate the effect of gamma irradiation on white spot syndrome virus （WS SV）. 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 1054/mL. Shrimp post-larvae （1-2 g） were treated with gamma-irradiated （different doses） WSSV （10^o 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 gamma- irradiated WSSV especially at 14-15 KGy.

Thermal Characteristics of PVA-PANI-ZnS Nanocomposite Film Synthesized by Gamma Irradiation Method

Gamma irradiation is employed for in situ preparation of PVA-PANI-ZnS nanocomposite. The irradiation dose is varied from 10 to 40 kGy at 10 kGy intervals. The XRD result confirms the formation of crystalline phases corresponding to ZnS nanoparticles, PVA and PANI. Field emission scanning electron microscopy shows the formation of agglomerated PANI along the PVA backbone, within which the ZnS nanoparticles are dispersed.UV-visible spectroscopy is conducted to measure the transmittance spectra of samples revealing the electronic absorption characteristics of ZnS and PANI nanoparticles. Photo-acoustic（PA） setup is installed to investigate the thermal properties of samples. The PA spectroscopy indicates a high value of thermal diffusivity for samples due to the presence of ZnS and PANI nanoparticles. Moreover, at higher doses, the more polymerization and formation of PANI and ZnS nanoparticles result in enhancement of thermal diffusivity.

The Effects of Gamma Irradiation on Molecular Weight, Morphology and Physical Properties of PHBV/Cloisite 30B Bionanocomposites

In this paper,the effects of gamma irradiation on Cast poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)and PHBV/Cloisite 30B(C30B)(3 wt%)bionanocomposite prepared by melt compounding,were evaluated at various doses,i.e.,5,15,20,50 and 100 kGy at room temperature in air.Changes in molecular weight,morphology and physical properties were investigated.The study showed that the main degradation mechanism occurring in gamma irradiation in both Cast PHBV and C-PHBV/3C30B bionanocomposite is chain scission,responsible for the decrease of molecular weight.Differential scanning calorimetry(DSC)data indicated a regular decrease in crystallization temperature,melting temperature and crystallinity index for all irradiated samples with increasing the dose.Further,DSC thermograms of both Cast PHBV and PHBV bionanocomposite exhibited double melting peaks due probably to changes in the PHBV crystal structure.Tensile and DMA data showed a reduction in Young’s modulus,strength,elongation at break and storage modulus with the radiation dose;the decrease was however more pronounced for Cast PHBV.The morphological damages were much less pronounced for the PHBV bionanocomposite sample compared to Cast PHBV,for which some irregularities and defects were observed at 100 kGy.This study highlighted the ability of C30B to counterbalance the detrimental effect of radiolytic degradation on the functional properties of PHBV up to 100 kGy,thus acting as a potential anti-rad.

Micro-Tuber Production in Diploid and Tetraploid Potato after Gamma Irradiation of in Vitro Cuttings for Mutation Induction

Micro-tubers are important propagules in potato breeding and potato production, and they are also dormant and easily transported and therefore good targets for mutation induction in potato mutation breeding. A prerequisite for mutation breeding is to determine optimal mutation treatments. Therefore, radio-sensitivity tests of a tetraploid and a diploid potato to gamma irradiation were undertaken. Effects of different gamma sources on radio-activity were also studied. In vitro potato cuttings were gamma irradiated using a wide dose range (0, 3, 6, 9, 12, 15 and 20 Gy). The irradiated cuttings were then cultured to induce micro-tubers directly in vitro. Micro-tuber morphotypes were assessed after irradiation of cuttings using three gamma sources with emission activities of 1.8, 7.07 and 139 Gy/min. The diploid species (Solanum verrucosum) was more radio-sensitive than the tetraploid cultivar Desirée (Solanum tuberosum). Gamma dose rates had significant influences on subsequent micro-tuber production at various mutant generations. Effects included reductions in the number, size and weight of micro-tubers produced. Gamma dose was more lethal for the diploid potato genotype and micro-tubers produced were small compared to those produced by the tetraploid genotype after irradiation. Different treatments are recommended for diploid and tetraploid potato irradiation in producing large mutant micro-tuber populations. The mutant micro-tuber populations may then be screened for interesting mutations/trait for both genetics and plant breeding purposes.

Improvement of Rice （Oryza sativa L.） var. Ciherang and Cempo Ireng Productivity Using Gamma Irradiation

Rice is the source of important food in the world. The demand of rice tends to increase every year, thus research to increase genetic variation of rice by gamma irradiation has been conducted. This research aimed to study the influence of gamma irradiation doses on the vegetative growth, yield and quality. The randomized completely block design was used with two factors --gamma irradiation doses and varieties. Two rice varieties were Ciherang and Cempo Ireng, while doses of gamma irradiation consisted of six levels： 0, 100, 200, 300, 400 and 500 Gy. The results indicated that the treatment of 200 Gy gamma irradiation to Ciherang could improve the number of grains/panicle, protein content, degraded plant height and amylose contents. Gamma irradiation to Cempo Ireng at dose of 200 Gy could improve the number of grains/panicle, 1,000 grain weight, while it decreased days to 50% heading and plant harvest age.

Effects of Gamma Irradiation on the Kinetics of the Adsorption and Desorption of Hydrogen in Carbon Microfibres

In this study, three types of carbon fibres were used, they were ex-polyacrylonitrile carbon fibres with high bulk modulus, ex-polyacrylonitrile fibres with high strength, and vapour grown carbon fibres. All the samples were subjected to a hydrogen adsorption process at room temperature in an over-pressured atmosphere of 25 bars. The adsorption process was monitored through electrical resistivity measurements. As conditioning of the fibres, a chemical activation by acid etching followed by γ-ray irradiation with 60Co radioisotopes was performed. The surface energy was determined by means of the sessile drop test. Both conditioning treatments are supplementary;the chemical activation works on the outer surface and the γ-irradiation works in the bulk material as well. Apparently, the most significant parameter for hydrogen storage is the crystallite size. From this point of view, the most convenient materials are those with small grain size because hydrogen is accumulated mainly in the grain boundaries.

An Approach on the Hydrogen Absorption in Carbon Black after Gamma Irradiation

In this work, different samples of an industrial carbon black are used to study the hydrogen intake from an over pressurized atmosphere and its changes due to alteration of its level of crystallinity produced by γ-irradiation. The monitoring of the hydrogen adsorption was made by means of thermogravimetric analysis and by measurements of some electrical parameters as the Seebeck coefficient. X-ray diffraction shows that the irradiation diminishes the level of crystalline perfection. These results show interesting possibilities to use carbon black as cheap hydrogen absorbers.

Stability of the Antioxidant Activity of Flavonoids after Gamma Irradiation

Food irradiation has the purpose of destroying insects or microorganisms, thereby increasing the safety and shelf life of foods. Flavonoids are ubiquitous plant secondary products with radical scavenger ability. In the present study their antioxidant stability after gamma irradiation was evaluated. The flavonoids showed fast scavenger ability measured with the 2.2-diphenyl-1-picrylhydrazyl radical (DPPH) after high doses of radiation. The low damage caused by irra- diation on antioxidant capacity of the flavonoids shows their potential use in combating chemical oxidation of bio- molecules in irradiated foods.

Analysis of variation in temperature-responsive leaf color mutant lines induced from Gamma irradiation in rice(Oryza sativa L.)

Eight lines of temperature-responsive leaf colormutants induced by applying 300 Gy Gamma-ray irradiation to Thermo-sensitive genic malesterile line 2177s,were obtained through con-tinuous selection in seven generations..Theleaves of these lines started to become greenafter the fourth leaf extension,and except

Synergistic Effects of Gamma Irradiation,Tensile Stress and Moisture on the Radiolysis of Silicone Foam

The present work involves the investigation of the synergistic effects of gamma irradiation,tensile stress and absorbed moisture on the radiolysis behaviors of silicone foams by experiments and theoretical simulations.For both the pristine and dehydrated samples,the permanent tensile set increases with the initial tensile strain.Further analysis uncovers that the dehydrated samples exhibit greater permanent tensile sets,lower further elongation and higher Young’s modulus than the counterparts of the pristine samples with the same initial tensile strain and gamma dose,verifying the vital synergistic effects on crosslinking network and aggregation structures caused by moisture and gamma radiation.The synergistic effects unveiled by reactive molecular dynamics at the atomic scale are due to the moisture-induced neutralization and stabilization of the macromolecular radicals.The steric hindrance of moisture located at the interface of silica and polymer chains also conduces to the observed synergistic effects due to the inhibited crosslinking reactions.

Gamma irradiation of 2-mercaptobenzothiazole aqueous solution in the presence of persulfate

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（S2O82-） 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-U）, 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.

Effects of Gamma Irradiation for Sterilization on Aqueous Dispersions of Length Sorted Carbon Nanotubes

There is currently great interest in the potential use of carbon nanotubes as delivery vessels for nanotherapeutics and other medical applications. However, no data are available on the effects of sterilization methods on the properties of nanotube dispersions, the form in which most medical applications will be processed. Here we show the effects of gamma irradiation from a 60Co source on the dispersion and optical properties of single-wall carbon nanotubes in aqueous dispersion. Samples of different length-refined populations were sealed in ampoules and exposed to a dose of approximately 28 kGy, a level sufficient to ensure sterility of the dispersions. In contrast to literature results for solid-phase nanotube samples, the effects of gamma irradiation on the dispersion and optical properties of the nanotube samples were found to be minimal. Based on these results, gamma irradiation appears sufficiently non-destructive to be industrially useful for the sterilization of nanotube dispersions.

Difference in electron-and gamma-irradiation effects on output characteristic of color CMOS digital image sensors

Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have been studied in comparison to those from theγ-irradiated sensors. For the electron-irradiated sensors, the non-uniformity increases obviouslyand a small bright region on the dark image appears at the dose of 0.4 kGy. The average brightnessincreases at 0.4 kGy, increases sharply at 0.5 kGy. The picture is very blurry only at 0.6 kGy,showing the sensor undergoes severe performance degradation. Electron radiation damage is much moresevere than γ radiation damage for the CMOS image sensors. A possible explanation is presented inthis paper.

The impact of gamma irradiation and storage on the physicochemical properties of tomato fruits in Ghana

Objectives:Tomato is a popular fruit that makes significant contributions to human nutrition for its content of sugars,acids,vitamins,minerals,lycopene,and other constituents.The fruit,however,has a short shelf life due to its climacteric nature.In view of this,an experiment was conducted to determine the effect of postharvest treatment on the physicochemical properties of fresh tomato fruits.Materials and Methods:Freshly harvested tomato fruits were subjected to 0,1,2,3,and 4 kGy gamma radiation and stored at 10±1℃ and 28±1℃.Parameters analysed during the study include pH,total titratable acidity,weight loss,total solids,and moisture content of the sample.Results:At both storage temperatures,results of the analyses were in the range of 2.80%-38.67%for weight loss,0.23%-0.51% for total titratable acidity,3.5%-5.0% for total soluble solids,94.43%-96.53% for moisture content,and pH was generally low in the samples stored at 10±1℃.Generally,gamma irradiation had an effect on the total soluble solids,total titratable acids,pH values,and moisture content and physiological weight loss at both storage temperatures.Conclusion:From the study,storing Burkina variety at a low temperature preserves the tomato fruits better than storing them at ambient temperature.

Micro-plasma noise of 30 krad gamma irradiation broken-down GaN-based LED

A correlation model between micro plasma noise and gamma irradiation of GaN-based LED is built.The reverse bias I-V characteristics and micro-plasma noise were measured in it, before and after Gamma irradiation. It is found that even after 30 krad Gamma irradiation, the GaN-based LED has soft breakdown failure. The reverse soft breakdown region current local instability of this device before irradiation is analyzed by the microplasma noise method. The results were obtained that if the GaN-based LED contained micro-plasma defects, it will fail after low doses（30 krad） of gamma irradiation. The results clearly reflect the micro-plasma defects induced carriers fluctuation noise and the local instability of GaN-based LED reverse bias current.

Thermoluminescent response of gamma irradiated Na^(+)–Cu^(+) ionexchanged silicate glass in large dose range

The introduction of metals into vitreous matrices is the origin of various interesting phenomena;in particular,the presence of copper ions in glass has been the subject of considerable research because of its numerous applications.The ion-exchange process is primarily used to introduce copper ions into glass matrices.The thermoluminescence(TL)of silicate glass was studied to evaluate its potential as gamma-sensitive material for dosimetric applications;the effect of copper doping on the thermoluminescent sensitivity was investigated using the Cu-Na ion-exchange technique for different concentrations and doping conditions,over a wide dose range of 10 mGy to 100 kGy.The results showed that Cu doping significantly improved the sensitivity of the glasses to gamma radiation.After the ion-exchange,two peaks appeared in the glow curves at approximately 175 and 230°C,respectively,which possibly originated from the Cu^(+) centers,along with a weak TL peak at around 320℃.We also attempted to explain the origin of the observed thermoluminescence by exploiting the Electron paramagnetic resonance(EPR)spectra.The results clearly show quenching of the TL emission with increasing copper concentrations.The present work indicates that the thermoluminescence response of these glasses to gamma rays can be reasonably measured in the range of 0.001-100 kGy.This study also facilitates the understanding of the basic TL mechanism in this glass system.

Layered Ag-graphene films synthesized by Gamma ray irradiation for stable lithium metal ano des in carb on ate-based electrolytes

Lithium metal batteries are considered as high energy density battery systems with very promising prospects and have bee n widely studied.However,The uncon trollable plating/strippi ng behavior,infinite volume change and den drites formation of lithium metal anode restrict the applicati on.The unc on trolled n ucleati on of lithium caused by the non uniform multi-physical field distributions,can lead to the undesirable lithium deposition.Herein,a graphene composite uniformly loaded with Ag nano-particles(Ag NPs)is prepared through a facile Gamma ray irradiation method and assembled into self-supported film with layered structure(Ag-rGO film).Whe n such film is used as a lithium metal an ode host,the uncontrolled deposition is converted into a highly nucleation-induced process.On one hand,the Ag NPs distributed between the in terlayers of graphe ne can preferentially induce lithium nu cleati on and en able uniform deposition morphology of lithium between interlayers.On the other hand,the stable layered graphene structure can accommodate volume change,stabilize the interface between anode and electrolyte and inhibit dendrites formation.Therefore,the layered Ag-rGO film as anode host can reach a high Coulombic efficiency over 93.3% for 200 cycle(786 h)at a current density of 1 mA cm^(-2) for 2 mAh cm^(-2) in carbonate-based electrolyte.This work proposes a facile Gamma ray irradiation method to prepare metal/3D-skeleton structure as lithium anode host and demonstrates the potential to regulate the lithium metal deposition behaviors via manipulating the distribution of lithiophilic metal(e.g.Ag)in 3D frameworks.This may offer a practicable thinking for the subsequent design of the lithium metal anode.

Fixation and Creep of Compressed Wood of Chinese Fir Irradiated with Gamma Rays

In order to discuss the mechanisms of permanent fixation of wood compression set , compressed wood of Chinese fir (Cunninghamia lanceolata) was irradiated by gamma rays from 60 Co. The irradiation doses were 0 (for match specim ens), 10 3, 5×10 3, 10 4, 5×10 4, 10 5, 5×10 5, 10 6, 5×10 6 Gy, res pectively. Then the weight loss, the equilibrium moisture content (EMC), the rec overy of wood compression set after adsorption (RSA) and the recovery after imme rsion in water (RSW), as well as the creep behaviour under a dry specimen condit ion and under an adsorption and subsequent desorption condition were measured an d discussed. This research proves that the doses of gamma irradiation have great effect on weight loss, EMC, RSA, RSW of irradiated compressed wood of Chinese f ir. The weight loss and the EMC increase, the RSA and the RSW fall drastically w hen the irradiation doses exceed 10 6 Gy. Both the instantaneous compliance and the creep compliance of the irradiated specimens under the two measurement cond itions show the general trend of increase with the increase of gamma irradiation doses. It can be deduced that decomposition or decrystallization reactions happ en in the wood cell wall at high gamma irradiation doses, especially at doses of around 5×10 6 Gy. In addition, this research proves that decomposition of mai n components of cell wall of compressed wood will lead to fixation of compressio n set of wood to a certain degree.

In Vitro Antioxidant and Radio Protective Activities of Lycopene from Tomato Extract against Radiation—Induced DNA Aberration

Background: The accumulation of free radicals is linked to a number of diseases. Free radicals can be scavenged by antioxidants and reduce their harmful effects. It is therefore essential to look for naturally occurring antioxidants that come from plants, as synthetic antioxidants are toxic, carcinogenic and problematic for the environment. Lycopene is one of the carotenoids, a pigment that dissolves in fat and has antioxidant properties. Materials and Methods: The antioxidant and free radical scavenging activity were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The impact of lycopene on bacteria (E. coli) susceptibility to γ-radiation was examined by radio sensitivity assay. The study also examined the induction of strand breaks in plasmid pUC19 DNA and how lycopene extract protected the DNA from γ-radiation in vitro. Results: At varying concentrations, lycopene demonstrated its ability to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH). IC50 for lycopene was determined at 112 μg/mL which was almost partial to IC50 of standard antioxidant L-ascorbic acid. The D10 value 180 Gy of E. coli was found to be >2-fold higher in the extract-containing lycopene sample than in the extract-free controls. The lycopene extracts inhibited the radiation-induced deterioration of the plasmid pUC19 DNA. At an IC50 concentration, lycopene provided the highest level of protection. Conclusion: Lycopene functions as an efficient free radical scavenger and possible natural antioxidant source. For cancer patients and others who frequently expose themselves to radiation, lycopene may be a useful plant-based pharmaceutical product for treating a variety of diseases caused by free radicals.