Effect Of Γ-radiation Research Articles

Effect of γ-radiation on silica aerogel and composite material for thermal insulation applications in nuclear power pipeline

SiO2 aerogel and its composite materials are considered as promising high-temperature thermal insulation materials due to their high porosity, low density and low thermal conductivity. However, a major obstacle for their application in nuclear power systems is the currently insufficient mechanism of the radiation effect. This study therefore aimed to investigated the changes in the microstructure, hydrophobic properties and thermal insulation properties of aerogel and ultrafine glass fiber reinforced aerogel composite (uGF/SiO2 aerogel) before and after γ-radiation, and explore the mechanism of the γ-radiation effect of aerogel materials. With an increase in cumulative radiation dose, the microstructure of aerogel suffered significant radiation damage, causing a gradual increase in crystallinity and thermal conductivity. When the cumulative dose reached 1700 kGy, the nanoparticles in the aerogel agglomerated and crystallized significantly, leading to an approximately 30 % increase in thermal conductivity. Notably, at the radiation of 1700 kGy, the uGF/SiO2 aerogel exhibited excellent structure stability, with a thermal conductivity of 31.60 mW/m·K, which was 3.27 % higher than that of unirradiated sample. This indicated the uGF/SiO2 aerogel exhibited excellent thermal performance and thermal stability even after γ-radiation. The study on the radiation effect of aerogel materials offers valuable insights for the composition optimization of aerogel used in nuclear power applications.

A study of the effect of γ-radiation on the current-carrying mechanism in the P-CuTlS2 single crystal

The electrical conductivity and volt–ampere characteristics (VAC) of the p-CuTlS2 single crystal with specific resistance [Formula: see text] and irradiated by [Formula: see text]-quantum were studied in the range of 100–300[Formula: see text]K temperature and 10–104[Formula: see text]V/cm. It was determined that the cause of the conduction disorder observed in the CuTlS2 single crystal at low electric fields and high radiation doses is the formation of defect clusters dominated by cation vacancies. A sharp increase in current at high electric fields and temperatures occurs as a result of thermo-field ionization of the acceptor level with activation energy [Formula: see text][Formula: see text]eV and the ionization voltage decreases with increasing radiation dose. Based on the determination of the parameters ([Formula: see text]) that determine the mechanism of current flow, the dependence of the shape of the potential hole on the radiation dose was determined.

Effect of apricot kernel seed extract on biophysical properties of chitosan film for packaging applications

Chitosan is a natural biodegradable biopolymer that has drawbacks in mechanical and antibacterial properties, limiting its usage in biological and medicinal fields. Chitosan is combined with other naturally occurring substances possessing biological antibacterial qualities in order to broaden its application. Ethanolic apricot kernel seed extract was prepared, analyzed, and incorporated into chitosan film with different concentrations (0.25, 0.5, and 0.75 wt%). Furthermore, the effect of AKSE and γ-radiation (20 Gy and 20 kGy) on the physical properties of the film was studied. The prepared films were characterized by Fourier transform infrared spectroscopy (FTIR), which revealed that AKSE did not cause any change in the molecular structure, whereas the γ-irradiation dose caused a decrease in the peak intensity of all concentrations except 0.75 wt%, which was the most resistant. In addition, their dielectric, optical, and antimicrobial properties were studied. Also, AKSE-enhanced optical qualities, allowed them to fully block light transmission at wavelengths of 450–600 nm. The dielectric properties, i.e., permittivity (ε′), dielectric loss (ε′′), and electrical conductivity (σ), increased with increasing AKSE concentration and film irradiation. The antimicrobial studies revealed that the antimicrobial activity against Escherichia coli and Canodida albicans increased with AKSE incorporation.

Individual and combinative effect of NaCl and γ-radiation on NADPH-generating enzymes activity in corn (Zea mays L.) sprouts

Being a universal reducing agent nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) plays an important role in the cellular metabolism and the implementation of anti-stress reactions in plants. There are only a few enzymes that ensure the NADPH pool formation in cells. Among them, the most important are glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49), malate dehydrogenase decarboxylating (DMDH, malic enzyme, EC 1.1.1.40) and NADP-isocitrate dehydrogenase (NADP-IDH, EC 1.1.1.42). The presented investigation is devoted to studying the influence of the individual and combinative effects of NaCl and γ-radiation as abiotic stress factors on biometric indicators and activity of these NADPH-generating enzymes, on organic content, and the formation of paramagnetic centers as defense reaction in corn (Zagatala-68 genotype) sprouts. It was found that 100 mM NaCl had an inhibitory effect on the development of sprouts. Relatively lower doses (50 Gy and 100 Gy) of γ-radiation had a positive, but its higher doses (150 Gy and 200 Gy) had a negative effect on this process. 500 Gy was a lethal dose (LD) for the corn sprouts. Combinative stress in all cases considerably delayed the development of sprouts. G6PDH showed the highest activity in the first, whereas, NADP-IDH showed the same activity in the last days of the experiment. All three enzymes, especially the G6PDH, have been activated in both root and stem tissues under the influence of stress factors (either radiation or salt). Combinative stress (γ-radiation + salt) also led to an induction of these activities which was necessary to neutralize the negative consequences of stress factors. Stress factors in all cases also had a negative effect on the content of organic matter in seedlings. Ionizing gamma radiation, which resulted in the formation of new paramagnetic centers as an anti-stress defense reaction in many cases was observed in wheat seedlings, but not in corn sprouts, which clearly shows that there are some differences in the protective mechanisms of these C3- and C4-types of plants to γ-radiation.

Cognitive Flexibility Is Selectively Impaired by Radiation and Is Associated with Differential Recruitment of Adult-Born Neurons.

Exposure to elevated doses of ionizing radiation, such as those in therapeutic procedures, catastrophic accidents, or space exploration, increases the risk of cognitive dysfunction. The full range of radiation-induced cognitive deficits is unknown, partly because commonly used tests may be insufficiently sensitive or may not be adequately tuned for assessing the fine behavioral features affected by radiation. Here, we asked whether γ-radiation might affect learning, memory, and the overall ability to adapt behavior to cope with a challenging environment (cognitive/behavioral flexibility). We developed a new behavioral assay, the context discrimination Morris water maze (cdMWM) task, which is hippocampus-dependent and requires the integration of various contextual cues and the adjustment of search strategies. We exposed male mice to 1 or 5 Gy of γ rays and, at different time points after irradiation, trained them consecutively in spatial MWM, reversal MWM, and cdMWM tasks, and assessed their learning, navigational search strategies, and memory. Mice exposed to 5 Gy performed successfully in the spatial and reversal MWM tasks; however, in the cdMWM task 6 or 8 weeks (but not 3 weeks) after irradiation, they demonstrated transient learning deficit, decreased use of efficient spatially precise search strategies during learning, and, 6 weeks after irradiation, memory deficit. We also observed impaired neurogenesis after irradiation and selective activation of 12-week-old newborn neurons by specific components of cdMWM training paradigm. Thus, our new behavioral paradigm reveals the effects of γ-radiation on cognitive flexibility and indicates an extended timeframe for the functional maturation of new hippocampal neurons.SIGNIFICANCE STATEMENT Exposure to radiation can affect cognitive performance and cognitive flexibility - the ability to adapt to changed circumstances and demands. The full range of consequences of irradiation on cognitive flexibility is unknown, partly because of a lack of suitable models. Here, we developed a new behavioral task requiring mice to combine various types of cues and strategies to find a correct solution. We show that animals exposed to γ-radiation, despite being able to successfully solve standard problems, show delayed learning, deficient memory, and diminished use of efficient navigation patterns in circumstances requiring adjustments of previously used search strategies. This new task could be applied in other settings for assessing the cognitive changes induced by aging, trauma, or disease.

Effects of γ-radiation on fluorite crystals with a trivalent rare-earth ions

The paper considers phenomena of formation of color centers due to intrinsic and impurity defects in fluorite crystals activated by rare-earth ions Pr3+, Nd3+, Yb3+ under γ- and UV-radiation. Using CaF2 activated with Yb3+ and Pr3+ ions as an example, the work shows the effect of the photodynamic process on the photochemical resistance to formation of color centers of a Yb-containing crystal. It also demonstrates the effect of heating on the restoration of the original color of a Pr-containing crystal after γ-radiation as a result of change in the electronic state of praseodymium ions. The features of the formation of ions in the R2+ state in CaF2:R3+ (R3+ = Pr, Nd, Yb) crystals after γ-irradiation are investigated and explained, and quantitative estimates of the R3+→R2+ conversion processes are given.

Gamma-radiation enhancement of sensing properties of FBGs in a few-mode polymer CYTOP fiber.

We investigate the effect of γ-radiation on temperature (T) and relative humidity (RH) sensitivities of polymer perfluorinated fiber Bragg gratings (FBGs). To this aim, different γ-radiation doses (80, 120, 160, and 520 kGy) were applied to a set of FBGs. We show that irradiated FBGs demonstrate an RH sensitivity rise with the received dose: from 13.3 pm/%RH for a pristine FBG up to 56.8 pm/%RH for a 520-kGy dose at 30℃. In contrast, T sensitivity decreases with radiation dose with a subsequent change of sign from positive to negative. Therefore, by experimental interpolation, T sensitivity can be eliminated at around a 160-kGy dose. This opens the possibility of designing an RH sensor with enhanced sensitivity, which at the same time is insensitive to T.

Joint effects of gamma radiation and zinc on duckweed Lemna minor L.

When assessing the consequences of combined chemical and radiation pollution on bodies of water, it is important to take into account the interaction of different factors, especially the possible synergistic increase in the toxic effect on growth, biochemical and physiological processes of living organisms. In this work, we studied the combined effect of γ-radiation and zinc on freshwater duckweed Lemna minor L. Irradiated plants (doses were 18, 42, and 63 Gy) were placed on a medium with an excess of zinc (3.15, 6.3, 12.6 μmol/L) for 7 days. Our results showed that the accumulation of zinc in tissues increased in irradiated plants when compared to non-irradiated plants. The interaction of factors in assessing their effect on the growth rate of plants was most often additive, but there was also a synergistic increase in the toxic effect at a zinc concentration of 12.6 μmol/L and irradiation at doses of 42 and 63 Gy. When comparing the combined and separate effects of gamma radiation and zinc, it was found that a reduction in the area of fronds (leaf-like plates) was caused exclusively due to the effects of radiation. Zinc and γ-radiation contributed to the enhancement of membrane lipid peroxidation. Irradiation stimulated the production of chlorophylls a and b, as well as carotenoids.

The Effects of γ-Radiation on the Physical and Electrical Properties of Silicone Encapsulation for Electronic Power Conditioners

Since the electronic power conditioner (EPC) is a crucial part of a space traveling-wave tube amplifier (STWTA), its reliability issue must be considered. The most effective way to prevent insulation breakdown is potting. Silicone elastomers are commonly used as an encapsulant for the EPC because of their good physical and electrical properties. The properties of the encapsulant and the interfaces change under the influence of γ-radiation, which may result in the failure of the potted modules. In this work, a comprehensive evaluation methodology is proposed for silicone-based potted modules, where besides physical and electrical properties, the effect of γ-radiation on the encapsulated interface is also considered. The results show that with the increase of the irradiation dose, the crosslinking density, hardness, elastic modulus, volume resistivity, dielectric constant, and storage modulus are increased by 301.6%, 76.3%, 289.7%, 396.1%, 5.0%, and 589.8%, respectively. In contrast, the elongation at break and dielectric loss factor are decreased by 83.8% and 57.8%. In addition, the tensile strength and breakdown strength first increase and then decrease, while the coefficient of thermal expansion of the interface shows the opposite trend. Since the interface bonding state does not change and the electric field strength of the tip decreases slightly with an increasing dielectric constant, the average value of the partial discharge inception voltage increased slightly.

Differential-thermal analysis and a microscopic study of the effect of γ-radiation on CuTlSe2 single crystal

Herein, the X-ray phase analysis (XPA) and differential-thermal analysis (DTA) of the CuTlSe2 compound obtained by the Bridgman–Stockbarger method have been investigated. As a result of the study, the values of energy absorption and mass losses of CuTlSe2 single crystal have been estimated depending on the temperature given their change mechanisms. The surface morphology of single crystals of the ternary coppercopounds (Cu-Tl-X ([Formula: see text])) in the initial state, annealing and after exposure to gamma-radiation is studied by atomic force microscopy. It is shown that the surface relief undergoes modification in the absorbed dose region of [Formula: see text] 500[Formula: see text]krad.

Hierarchical Self-Assembly in DNA Ionogel: Effect of γ-Radiation on Gel Properties

DNA ionogels prepared by adding 1-ethyl-3-methylimidazolium chloride on low energy gamma irradiated DNA solution samples reveal non-trivial self-assembly. Variations in secondary structure and low-frequency gel rigidity modulus G0 captured this unique hitherto unexplored features of these gels. Interestingly, at higher radiation dose (0 to 100 Gy) samples could partially lose their initial rigidity. Dynamic light scattering revels dose dependent relaxation dynamics corresponding to ergodicity breaking time. In particular, viscosity and rheology showed that the time of gelation tgel, temperature of gelation Tgel and strength of gelation G0 are gamma ray dose dependent. DNA Ionogel melting with temperature shows self-assembled characteristics of this biomaterial. Gelation kinetics of ionizing radiation treated DNA strands have been studied in literature.

Ultrafine iron particles/polystyrene composites: effects of gamma radiation and manufacture aging on the AC electrical characterization

The present investigation deals with the effects of the (gamma) γ-radiation and samples’ aging on the ac electrical properties of ultrafine iron polystyrene composites. The composites with an average thickness of 1.07 mm contain different iron particle concentrations (10, 20 and 30) by weight %. The results show that the ac electrical properties of the γ-irradiated composites are different from the non-irradiated ones. Rather relative changes in values after irradiation were registered for the impedance, dielectric constant, and the ac electrical conductivity. After irradiation, both the conductivity and the dielectric constant are enhanced relatively with the impedance becoming relatively lower in value. Also, the results show that the age of the samples affects the ac electrical properties of the tested composites. It has been found that after a few years, the electrical conductivity of the composites becomes lower in value compared to what it was a few years ago, which indicates that composites tend to lose their desired electrical properties with passage of time. So, as a potential solution for this physical behavior, the samples were exposed to γ-radiation in an attempt to enhance the metal–polymer bonding and release more free electrons within the composites. The properties such as impedance, dielectric constant, electrical conductivity of the composites were studied before and after γ-irradiation. Later, these studied electrical properties were compared with results reported few years ago. The frequency range applied in this study is consistent with Jonscher’s power law model.

Effects of γ-radiation on chickpea (Cicer arietinum) varieties and their tolerance to salinity stress

Chickpea (Cicer arietinum L.) is a bisexual and self-pollinated legume. It improves the soil fertility through its natural ability to fix atmospheric nitrogen with its symbiotic bacteria. Salinity is one of the most important abiotic stress factors affecting plant growth. γ-radiation is a very effective tool for inducing mutations in many plants. This study evaluated the γ-radiation effect on germination, cell division and plant growth of first-generation plants. Seeds of seven chickpea varieties were irradiated with γ-radiation doses ranging between 50 Gy and 600 Gy. Non-significant differences in germination percentage were recorded for seeds exposed to 50 Gy, 100 Gy, and 200 Gy of γ-radiation in comparison to the corresponding controls except ILC 484. The mitotic index (MI) of root cells increased at the low doses of 50 Gy, 100 Gy and 200 Gy comparing and reduced at the higher doses in all chickpea varieties to the control. All doses of γ-radiation induced a variable range of chromosomal abnormalities; the most common were bridges, laggard chromosomes, stickiness at metaphase, chromosome breaks, micronuclei and binucleate cells. The 300 Gy to 600 Gy doses induced degradation of nuclear membranes. The salinity treatments at 25 mM NaCl and 60 mM NaCl reduced seedling’s growth of all cultivars. The dose of 100 Gy alleviated the impact of salinity at a concentration of 25 mM NaCl for all varieties, except FLIP 84-188 and FLIP 97-263. The 60 mM NaCl treatment significantly reduced early growth of all cultivars and its effect was not alleviated by the γ-radiation.

The impact of background γ-radiation on erythrocyte nuclear pathology, the serotonergic system, and cytochrome P-450 in hens (GALLUS GALLUS DOMESTICUS) from Azerbaijan.

High levels of background γ-radiation exist in the suburbs of Baku, Azerbaijan. We examined the impact of radiation on erythrocyte nuclear pathologies, levels of cytochrome P-450, and serotonin-modulating anticonsolidation protein (SMAP) in the tissues of the hens from three settlements with different levels of background radiation. Higher levels of radiation resulted in increased nuclear pathologies, upregulation of tissue SMAP levels, and downregulation of cytochrome P-450. We also carried out controlled dosage studies on Wistar male rats, which showed significant upregulation of heat shock proteins with molecular mass 70 kDa (HSP70) in the bone marrow 3 and 5 h after SMAP intraperitoneal administration. Administration of SMAP to rats 3 h prior to γ-radiation exposure (8 Gy) provided significant protection to somatic cell nuclei. We conclude that SMAP can provide protection from the genotoxic effects of γ-radiation through upregulation of HSP70 or the transformation of chromatin into a condensed, more protective conformational state.

Optimizing the Fabric Architecture and Effect of γ-Radiation on the Mechanical Properties of Jute Fiber Reinforced Polyester Composites.

The fiber architecture can significantly influence the rate of impregnation of a resin in making composites and the load-bearing ability of individual fibers on testing of the loading directions. Moreover, achieving the maximum mechanical performance of a natural fiber composite selection of yarn liner density and optimization of fabric structure and further modification of the composites remains a great challenge for the composite research community. In this study, a number of jute-based woven derivatives (plain, 2/1 twill, 3/1 twill, zigzag based on a 2/2 twill, and diamond based on a 2/2 twill) have been constructed from similar linear densities of yarn. The effect of the fabric architecture and further modification of optimized composites by applying γ-radiation is also explained in this study. The experimental results show a 54% increase in tensile strength, a 75% increase in tensile modulus, a 69% increase in flexural strength, a 124% increase in flexural modulus, and 64% increase in impact strength of twill (3/1) structured jute fiber polyester composites in comparison to other plain and twill structured composites. A further mechanical improvement of around 20–30% is possible for the optimized twill structured composites by applying γ-radiation on the composites. An FTIR, TGA, and SEM study confirms the chemical, thermal, and fractographic changes after applying the modification of composites.

Polarity-Specific Profiling of Metabolites in Single Cells by Probe Electrophoresis Mass Spectrometry.

Sensitive analysis of metabolites in a single cell is of fundamental significance for the better understanding of biological variability, differential susceptibility in disease therapy, and cell-to-cell heterogeneity as well. Herein, polarity-specific profiling of metabolites in a single cell was implemented by probe electrophoresis mass spectrometry (PEMS), which combined electrophoresis sampling of metabolites from a single cell and nanoelectrospray ionization-mass spectrometry (nanoESI-MS) analysis of the sampled metabolites. Enhanced extraction of either negatively or positively charged metabolites from a single cell was achieved by applying a DC voltage offset of +2.0 and -2.0 V to the probe, respectively. The experimental data demonstrated that PEMS features high throughput (≥200 peaks) and high sensitivity (≥10-times signal enhancement for [Choline + H]+, [Glutamine + H]+, [Arginine + H]+, etc.) in comparison with direct nanoESI-MS analysis. The biological effects of CdSe quantum dots (QDs) and γ-radiation on Allium cepa cells were investigated by PEMS, which revealed that CdSe QDs lead to the increase of intracellular amines while γ-radiation causes the decrease of intracellular acids. Therefore, this work provides an alternative platform to probe novel insights of cells by sensitive analysis of polarity-specific metabolites in a single cell.

Combination of NOS- and PDK-Inhibitory Activity: Possible Way to Enhance Antitumor Effects.

We have previously demonstrated a high antitumor potential of NOS inhibitor T1023 (1-isobutanoyl-2-isopropylisothiourea hydrobromide): antitumor antiangiogenic activity in several animal tumor models and its ability to synergistically enhance the antitumor effects of bevacizumab, cyclophosphamide and γ-radiation. At the same time, rather rapid adaptation of experimental neoplasias to T1023 treatment was often observed. We attempted to enhance the antitumor activity of this NOS inhibitor by supplementing its molecular structure with a PDK-inhibiting fragment, dichloroacetate (DCA), which is capable of hypoxia-oriented toxic effects. We synthesized compound T1084 (1-isobutanoyl-2-isopropylisothiourea dichloroacetate). Its toxic properties, NOS-inhibiting and PDK-inhibiting activity in vivo, and antitumor activity on the mouse Ehrlich carcinoma model (SEC) were investigated in compare with T1023 and Na-DCA. We found that the change of the salt-forming acid from HBr to DCA does not increase the toxicity of 1-isobutanoyl-2-isopropylisothiourea salts, but significantly expands the biochemical and anti-tumor activity. New compound T1084 realizes in vivo NOS-inhibiting and PDK-inhibiting activity, quantitatively, at the level of the previous compounds, T1023 and Na-DCA. In two independent experiments on SEC model, a pronounced synergistic antitumor effect of T1084 was observed in compare with T1023 and Na-DCA at equimolar doses. There were no signs of SEC adaptation to T1084 treatment, while experimental neoplasia rapidly desensitized to the separate treatment of both T1023 and Na-DCA. The totality of the data obtained indicates that the combination of antiangiogenic and hypoxia-oriented toxic effects (in this case, within the molecular structure of the active substance) can increase the antitumor effect and suppress the development of hypoxic resistance of neoplasias. In general, the proposed approach can be used for the design of new anticancer agents.

Effects of Low-dose Gamma Radiation on Expression of Apoptotic Genes in Rat Peripheral Blood Lymphocyte.

Background: Exposure to high-dose ionizing radiation is known as a human carcinogen factor, but our information about the effects of low-dose ionizing radiation such as occupational exposures is limited. The main concern of scientific community is biological consequences due to low-dose radiations.Objective: This study aims to evaluate the effects of low-dose γ-radiation on expression changes of apoptotic genes (bax and bcl-2) in the rat peripheral blood lymphocytes.Material and Methods: In this experimental study, 42 adult male rats were classified into 6 groups, which was exposed to various doses values ranged from 20 mGy to 1000 mGy by γ-rays from a Co-60 source. Blood samples were provided for analysis of gene expression 24 h after gamma radiation by relative quantitative Reverse Transcription - Polymerase Chain Reaction (RT-PCR). Radiation sensitivity of rat lymphocytes was measured by the bax/bcl-2 ratio as a predictive marker for radio-sensitivity. Results: The results of this study showed that low dose of gamma radiation can induce down-regulation of bax in rat peripheral blood lymphocytes. Despite other mechanisms of cellular radio-protection, changes in expression of these apoptotic genes can be the primary pathway in responses of the lymphocytes radio-protection to the exposure. Our study revealed a significant decrease in the bax/bcl-2 ratio at 50 mGy dose compare to control and the other irradiated groups (p < 0.05).Conclusion: These results suggest that changes in the bax/bcl-2 ratio especially in radiation workers, as a key factor in apoptosis, can be considered as a biological marker in low-dose gamma radiation.

Role of leptin/STAT3 signaling and RIP-kinases in fucoxanthin influences on mice exposed to LPS and gamma radiation

Endotoxemia remains a critical clinical dilemma due to high mortality rate provoked by the systemic inflammatory response, which often leads to sever hepatic injury and immune dysregulation. This study aimed at delineating the modulatory effect of fucoxanthin (FX) and γ-radiation (IR) on LPS-induced spleen and liver injury. LPS sensitized mice showed enhanced splenic and hepatic TLR4/NF-κB- signaling, suppressed splenic α-7nAchR-expression, activated hepatic RIPK/HMGB-1, impaired hepatic leptin/STAT-3 signaling, extensive oxidative stress, and marked apoptosis with sever degenerative histopathological examination. FX and/or IR protected liver and spleen against detrimental effects evoked by LPS. Overall, FX and/or IR exhibited protective effect against endotoxemia.

A Review of the Effect of Irradiation on the Corrosion of Copper-Coated Used Fuel Containers

Radiation induced corrosion is one of the possible modes of materials degradation in the concept of long-term management of used nuclear fuel. Depending on the environmental conditions surrounding the used fuel container, a range of radiolysis products are expected to form that could impact the corrosion of the copper coating. For instance, γ-radiolysis of pure water produces molecular oxidants such as H2O2 and the radiolysis of humid air produces compounds such as NOx and HNO3. This review is confined to a discussion of the effect of γ-radiation on the corrosion of copper-coated containers. A simplified mixed-potential model is also presented to calculate the extent of copper corrosion by using the steady-state concentration of H2O2 generated during the first 300 years of emplacement, when the radiation field is significant.