High Doses Of Gamma Radiation Research Articles

Modification of WS2 thin film properties using high dose gamma irradiation

The tunability of the transition metal dichalcogenide properties has gained attention from numerous researchers due to their wide application in various fields including quantum technology. In the present work, WS2 has been deposited on fluorine doped tin oxide substrate and its properties have been studied systematically. These samples were irradiated using gamma radiation for various doses, and the effect on structural, morphological, optical and electrical properties has been reported. The crystallinity of the material is observed to be decreased, and the results are well supported by x-ray diffraction, Raman spectroscopy techniques. The increase in grain boundaries has been supported by the agglomeration observed in the scanning electron microscopy micrographs. The XPS results of WS2 after gamma irradiation show evolution of oxygen, carbon, C=O, W–O and SO4 −2 peaks, confirming the addition of impurities and formation of point defect. The gamma irradiation creates point defects, and their density increases considerably with increasing gamma dosage. These defects crucially altered the structural, optical and electrical properties of the material. The reduction in the optical band gap with increased gamma irradiation is evident from the absorption spectra and respective Tauc plots. The I–V graphs show a 1000-fold increase in the saturation current after 100 kGy gamma irradiation dose. This work has explored the gamma irradiation effect on the WS2 and suggests substantial modification in the material and enhancement in electrical properties.

Optical properties of thin films monitored in real-time at high gamma radiation doses using long period fiber gratings

In this work, we report an all-optical-fiber-based method to monitor in real-time the changes in thin film optical properties when exposed to harsh environments such as high doses of gamma radiation. The method is based on a long period grating (LPG) inscribed in a radiation resistant optical fiber, which is coated with a thin film to be analyzed. Due to impact of the environment on the film properties, the transmission spectrum of the LPG changes. To validate this methodology, we deposited oxides of various metals, i.e. aluminum (Al2O3), titanium (TiO2), and tantalum (Ta2O5), as well as a polymeric film, namely polystyrene (PS), on the LPG surface and measured the resonant wavelength shift induced by high doses of gamma exposure (dose rate of 2.3 kGy/h, up to a total dose of 46 kGy). The changes could be observed in real-time up to maximum reached dose and during the recovery period. The results are significantly dependent on thin film material. Among the oxides, TiO2 thin film demonstrated the highest susceptibility to irradiation, whereas Al2O3 exhibited the least impact. Additionally, a good recovery potential for Ta2O5 thin film was observed, hinting at its promising application in dosimetry. Conversely, the PS film exhibited a permanent effect induced by irradiation. This is the first real-time experimental study of the impact of high dose gamma radiation on thin film optical properties using a universal optical-fiber-based device. The findings pave the way for assessing radiation hardness of thin film materials or utilizing such a method to optimize material treatment involving ionizing radiation.

Study of bulk damage of high dose gamma irradiated p-type silicon diodes with various resistivities

The bulk damage of p-type silicon detectors caused by high doses of gamma irradiation has been studied. The study was carried out on three types of n+-in-p silicon diodes with comparable geometries but different initial resistivities. This allowed to determine how different initial parameters of studied samples influence radiation-induced changes in the measured characteristics. The diodes were irradiated by a Cobalt-60 gamma source to total ionizing doses ranging from 0.50 up to 8.28 MGy, and annealed for 80 minutes at 60 °C. The Geant4 toolkit for simulation of the passage of particles through matter was used to simulate the deposited energy homogeneity, to verify the equal distribution of total deposited energies through all the layers of irradiated samples, and to calculate the secondary electron spectra in the irradiation box. The main goal of the study was to characterize the gamma-radiation induced displacement damage by measuring current-voltage characteristics (IV), and the evolution of the full depletion voltage (V FD) with the total ionizing dose, by measuring capacitance-voltage characteristics (CV). It has been observed that the bulk leakage current increases linearly with total ionizing dose, and the damage coefficient depends on the initial resistivity of the silicon diode. The effective doping concentration and therefore V FD significantly decreases with increasing total ionizing dose, before starting to increase again at a specific dose. We assume that this decrease is caused by the effect of acceptor removal. Another noteworthy observation of this study is that the IV and CV measurements of the gamma irradiated diodes do not reveal any annealing effect.

Studies of chemical bonds loss and optical modifications of CR-39 caused by gamma rays

The induced impacts of high doses of gamma irradiation on the structural variations of poly-allyl-diglycol carbonate (PADC) polymers (CR-39) were studied in terms of X-ray diffraction (XRD) patterns. CR-39 samples were irradiated separately at different ranging from 200 to 800 kGy; (step 200). A deconvolution process of the XRD spectra of CR-39 samples for all gamma irradiation doses was performed. The results of this deconvolution process for the pristine specimen show three diffraction peaks at about 20.30°, 28.16° and 41.70° of 2θ. The broad peaks at 28.16o and 41.70°, and the highest peak at 20.30° of XRD confirm the amorphous nature and low degrees of crystallinity, respectively. The position, area, intensity and full width at half maximum of these peaks are changed with further doses of gamma irradiation. With additional gamma irradiations, the intensities of all peaks decrease significantly. The highest and sharpest peak properties are employed to determine the crystallinity, crystallite size, and radiation chemical yield (G-value) for the loss of carbonate ester bonds using a proposed method. Higher doses of gamma irradiation result in a decrease in crystallinity while increasing crystallite size. Furthermore, the optical band gaps reduced from 4.81 to 3.49 eV when the irradiated dose increased from 0 to 800 kGy. Furthermore, the third order nonlinear susceptibility increased from 0.84x10−12 esu to 2.25x10−12 esu with increasing the radiation doses from 0 to 800 kGy. Moreover, the nonlinear refractive increased from 1.52x10−11 to 3.69x10−11 with increasing the radiation doses from 0 to 800 kGy. On the other hand, the number of carbon atoms in each cluster increased from 51 to 97 when the irradiated dose increased from 0 kGy to 800 kGy.

Gamma Irradiation Doses reduce Cooking time and Improve Nutritional Profile of selected Pigeon pea [Cajanus cajan (L.) Millsp] Genotypes in Nigeria

Pigeon Pea (Cajanus cajan L.) is a self-pollinating perennial legume shrub with over 30,000 accessions deposited world-wide. Despite the nutritional importance of pigeon peas, its detrimental traits such as its long cooking time, has led to low cultivation of the crop and inhibit its consumers’ request. Concerted efforts to improve both the quality and quantity of this crop through mutation breeding informed this research. It was based on this premise that the study was aimed to evaluate gamma irradiation influences on the nutrient quality and cooking duration of selected pigeon pea varieties in Nigeria. Four accessions of pigeon peas (‘NG/SA/11/08/108’, ‘NG/AO/MAY/00/021/01’, ‘TCC-2’ and ‘NG/SA/07/191’) were obtained from National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan. They were irradiated at the Oncological Department ABU Teaching Hospital, Shika, Zaria, using Cobalt-60 (60CO) irradiation source. Standard procedures were followed to determine the effects of the irradiation on cookability and nutritional profile of the M1 plants and their respective controls. It was established that all the parameters tested were irradiation dose dependent. In NG/AO/MAY/00/021/01, 100 Gy produced the highest protein (20.40 %) and highest carbohydrate (68.93 %) contents. Anti-nutritional factors such as cyanide were lower (48.83, 46.22, 43.65 and 44.75 mg/kg in NG/AO/MAY/00/021/01, NG/SA/11/08/108, NG/SA/07/191 and TCC-2) at 400 Gy than those of their respective controls (54.83, 56.83, 53. and 53.55 mg/kg). The amount of Magnesium increased with higher doses of gamma irradiation (1.37 g/100 g for 200 Gy NG/AO/MAY/00/021/01; 1.03 g/100g for 400 Gy NG/SA/11/08/108 and 1.13 g/100 g for TCC-2). There were significant reductions in cooking time in 400 Gy treatments for all the genotypes. The differences between the control and the least cooking time in 400 Gy were 11, 16, 22 and 15 minutes for NG/AO/MAY/00/021/01, NG/SA/11/08/108, NG/SA/07/191 and TCC-2, respectively. It was therefore concluded that these variations could be exploited for further improvement of the crop for food security. Keywords: Cooking time, Mutation breeding, Gamma irradiation, Cookability, Dose dependent

Impact of the gamma and electron beam irradiations on yeast-spot disease fungal agent and physicochemical attributes of hazelnut (Corylus avellana L.)

In this study, the effects of gamma irradiation (GMI) and electron beam irradiation (EBI) on the yeast spot fungus Eremothecium coryli isolated from hazelnuts and the physicochemical features of irradiated hazelnut samples were evaluated. Results demonstrated that GMI doses ≥2 and EBI doses ≥4 effectively removed E. coryli from artificially contaminated hazelnuts and reduced the contamination by 5 log CFU/g. GMI and EBI at higher doses resulted in an increment in malondialdehyde content (MDA) and a change in the profile of fatty acids. Both treatments caused an enhancement in total phenolic content (TPC) and antioxidant activity in the DPPH assay but declined antioxidant activity in the ABTS assay at a dose of 6 kGy. L*, a*, and b* color indices were changed, and the surface color of the hazelnuts became darker. Total protein solubility (TSP) and protein profile of the samples were affected by GMI and EBI. Higher doses of GMI and EBI reduced the hardness of the hazelnuts and led to a more fragile texture. The overall acceptability of the samples was adversely affected by GMI, but it was not affected by EBI treatment. Hence, GMI (≥2 kGy) and EBI (≥4 kGy) have the potential to be applied as a fungal disinfection method; lower doses (≥2 kGy) of both treatments can sustain desirable physicochemical attributes and sensory characteristics of hazelnuts.

Changes in physicochemical characteristics of cation exchange resins by high dose gamma irradiation

Chemical and thermal characteristics of cation exchange resins were examined after irradiation of gamma rays. The degradation of cation exchange resins was mainly observed at doses of up to 500 kGy, whereas the balance between degradation and cross-linking reactions was sustained at 700 kGy. While the carbon content decreased significantly up to a maximum dose of 500 kGy, it showed an increase at higher doses. Conversely, the oxygen content exhibited a decrease in contrast to the carbon content. The continuous reduction in sulfur content was attributed to the decomposition of sulfonic groups. Gamma-ray irradiation caused a decrease in the initiation temperature of sulfonic groups and PS-DVB, but unlike the chemical properties of cation exchange resins due to gamma-ray irradiation, the thermal properties of resins remained unaffected.

Low-Dose Ionizing Radiation-Crosslinking Immunoprecipitation (LDIR-CLIP) Identified Irradiation-Sensitive RNAs for RNA-Binding Protein HuR-Mediated Decay.

Although ionizing radiation (IR) is widely used for therapeutic and research purposes, studies on low-dose ionizing radiation (LDIR) are limited compared with those on other IR approaches, such as high-dose gamma irradiation and ultraviolet irradiation. High-dose IR affects DNA damage response and nucleotide-protein crosslinking, among other processes; however, the molecular consequences of LDIR have been poorly investigated. Here, we developed a method to profile RNA species crosslinked to an RNA-binding protein, namely, human antigen R (HuR), using LDIR and high-throughput RNA sequencing. The RNA fragments isolated via LDIR-crosslinking and immunoprecipitation sequencing were crosslinked to HuR and protected from RNase-mediated digestion. Upon crosslinking HuR to target mRNAs such as PAX6, ZFP91, NR2F6, and CAND2, the transcripts degraded rapidly in human cell lines. Additionally, PAX6 and NR2F6 downregulation mediated the beneficial effects of LDIR on cell viability. Thus, our approach provides a method for investigating post-transcriptional gene regulation using LDIR.

High-Dose Ionizing Radiation Impairs Healthy Dendrite Growth in C. elegans

PurposeThe nervous system is vulnerable to radiation damage, and further optimization is required to increase the efficacy of radiotherapy while reducing harm to neurons. Given recent developments in heavy ion therapy, experimental models would be valuable to improve these therapies. Here, we utilized the nematode Caenorhabditis elegans (C. elegans) to evaluate the effects of high-dose radiation on neuron development. Methods and MaterialsIn this study, we used confocal microscopy to assess dendritic growth of the PVD nociceptor following high-dose gamma-irradiation from a Cs-137 source. ResultsIrradiation during an early larval stage (L2) delayed overall development but also independently impaired dendrite outgrowth in the PVD nociceptive neuron. Irradiation at L4 larval stage did not result in significant alterations in dendrite morphology. ConclusionsThe nematode C. elegans can serve as a high-throughput model to study the effects of high-dose radiation on dendrite growth. We propose that C. elegans can be useful for studies of experimental radiation therapy modalities and dose rates for translational research.

A human lung alveolus-on-a-chip model of acute radiation-induced lung injury

Acute exposure to high-dose gamma radiation due to radiological disasters or cancer radiotherapy can result in radiation-induced lung injury (RILI), characterized by acute pneumonitis and subsequent lung fibrosis. A microfluidic organ-on-a-chip lined by human lung alveolar epithelium interfaced with pulmonary endothelium (Lung Alveolus Chip) is used to model acute RILI in vitro. Both lung epithelium and endothelium exhibit DNA damage, cellular hypertrophy, upregulation of inflammatory cytokines, and loss of barrier function within 6 h of radiation exposure, although greater damage is observed in the endothelium. The radiation dose sensitivity observed on-chip is more like the human lung than animal preclinical models. The Alveolus Chip is also used to evaluate the potential ability of two drugs - lovastatin and prednisolone - to suppress the effects of acute RILI. These data demonstrate that the Lung Alveolus Chip provides a human relevant alternative for studying the molecular basis of acute RILI and may be useful for evaluation of new radiation countermeasure therapeutics.

Synergistic effect of Gamma-Irradiation on morphological, structural, and optical properties of Carbon-coated Nickel Cobalt Oxide/rGO nanocomposites

Radiation exposure induces defects in the crystal structure, leading to alterations in the structural, optical, and morphological properties of metal oxides. These irradiated metal oxides have found extensive use in various household applications. In this particular investigation, carbon-coated nickel cobalt oxide/rGO nanocomposites were synthesized through ultrasonication. Subsequently, these nanocomposites were subjected to three different doses of gamma radiation using a 60Co source. Both un-irradiated and irradiated samples were subjected to characterization using FTIR, SEM, XRD, and UV-Vis spectroscopy. The FTIR analysis confirmed the presence of a spinel-type structure in NiCo2O4. SEM analysis revealed the presence of crumbled sheets of rGO, and the irradiation process caused a transformation of these stacked sheets into thinner sheets. XRD analysis indicated a decrease in crystalline size and an increase in dislocation density with higher doses of gamma irradiation. UV-Vis spectroscopy demonstrated a reduction in both direct and indirect optical band gaps as a result of gamma irradiation. Furthermore, it was observed that Urbach energy and refractive index increased with gamma irradiation. Based on these findings, it can be concluded that gamma irradiation has a significant impact on the morphological, structural, and optical properties of NiCo2O4/rGO@C nanocomposites.

Transcriptomic and genomic effects of gamma-radiation exposure on strains of the black yeast Exophiala dermatitidis evolved to display increased ionizing radiation resistance.

Melanized fungi thrive in extreme environments, including those with high levels of ionizing radiation. To understand the role that melanin may play in ionizing radiation resistance, we previously performed an adaptive laboratory evolution experiment in which we used melanized and non-melanized strains of the yeast Exophiala dermatitidis to develop evolved lines that exhibit increased ionizing radiation resistance. In this study, we further characterized these evolved lines by analyzing their response to ionizing radiation at the transcriptomic and genomic levels. RNA sequencing showed that the response to gamma irradiation in both unevolved and evolved strains involved the induction of DNA repair genes. However, in the melanized lines evolved to exhibit increased ionizing radiation resistance, DNA-associated genes were constitutively expressed, compared to their expression levels in wild type. Non-melanized lines that were evolved to be resistant to ionizing radiation, on the other hand, exhibited upregulation of genes involved in redox homeostasis, even under non-irradiated conditions. Additionally, we characterized genome-wide mutations induced by a single high dose of gamma radiation in these evolved lines and observed that while melanin did not directly affect survival after gamma radiation exposure, melanized lines that evolved to exhibit higher ionizing radiation resistance experienced fewer mutations, whereas similarly evolved, non-melanized lines accumulated more mutations, similar to the parent, non-melanized strain. These results underscore the complex yet measurable role of melanin in the response to ionizing radiation in E. dermatitidis. Furthermore, this study enhances our understanding of the mechanisms underlying the recovery after ionizing radiation exposure in melanized fungi and offers insights into the potential therapeutic applications of melanin and other redox molecules for protecting against ionizing radiation-induced damage. IMPORTANCE Ionizing radiation poses a significant threat to living organisms and human health, given its destructive nature and widespread use in fields such as medicine and the potential for nuclear disasters. Melanized fungi exhibit remarkable survival capabilities, enduring doses up to 1,000-fold higher than mammals. Through adaptive laboratory evolution, we validated the protective role of constitutive upregulation of DNA repair genes in the black yeast Exophiala dermatitidis, enhancing survival after radiation exposure. Surprisingly, we found that evolved strains lacking melanin still achieved high levels of radioresistance. Our study unveiled the significance of robust activation and enhancement of redox homeostasis, as evidenced by the profound transcriptional changes and increased accumulation of mutations, in substantially improving ionizing radiation resistance in the absence of melanin. These findings underscore the delicate balance between DNA repair and redox homeostasis for an organism's ability to endure and recover from radiation exposure.

Gamma irradiation synthesis and modification of palladium supported on graphene oxide as oxygen reduction reaction electrocatalyst

This work aims to investigate the preparation of palladium (Pd) particles on graphene oxide (GO) support via gamma radiolysis and to study their electrochemical activity towards the oxygen reduction reaction (ORR). The results show that the Pd precursor concentration used in the preparation process influences the loading, size, and distribution of the Pd particles. The electrochemical analysis shows that the Pd/GO samples synthesized through gamma radiolysis exhibit excellent activity toward ORR. Additionally, the gamma irradiation used in the synthesis process shows beneficial effects on the Pd/GO. High gamma irradiation doses increase the electron transfer number and reduce the peroxide yield of the Pd/GO.

High Dose Gamma Radiation Induced Modifications in Chemical, Electrical and Morphological Properties of PES Polymer

High Dose Gamma Radiation Induced Modifications in Chemical, Electrical and Morphological Properties of PES Polymer

Fourier Transform IR Spectroscopic Study of the Influence of a High Dose of Gamma Radiation on the Composition of Functional Groups in Potato Tubers

Fourier Transform IR Spectroscopic Study of the Influence of a High Dose of Gamma Radiation on the Composition of Functional Groups in Potato Tubers

Novel polyvinyl alcohol film dosimeter containing 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye for high dose application

A new dyed polyvinyl alcohol (PVA) film dosimeter based on 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MMT) tetrazolium dye is proposed in this study for measuring high gamma radiation dose. Gamma cell irradiator that contains Co-60 gamma-ray source was used to expose the novel MMT-PVA films to different doses up to 25 kGy. The changed in optical property of irradiated and unirradiated films were characterized by UV–Vis spectrophotometer. The results show that the dose sensitive and the linear range of irradiated films were increased considerably with increase of MMT concentration from 1 to 5 mM. The dose response of dyed PVA film changed substantially with changing relative humidity (12–74%) as well as irradiation temperature (10–40 °C). The absorbance of the un-irradiated films does not change up to 10 days in dark while a significant increase in their absorbance was reported for similar films under fluorescent light. The irradiated dosimeters that kept in dark showed a perfect stability for 54 days. It was found that no obvious impact of dose rate on the irradiated MMT-PVA film dosimeters.

Fourier Transform IR Spectroscopic Study of the Influence of a High Dose of Gamma Radiation on the Composition of Functional Groups in Potato Tubers

Fourier Transform IR Spectroscopic Study of the Influence of a High Dose of Gamma Radiation on the Composition of Functional Groups in Potato Tubers

EFFECT OF GAMMA IRRADIATION ON Salvia officinalis L. AND Melissa officinalis L. IN VITRO PLANTS

Salvia officinalis L. (sage) and Melissa officinalis L. (lemon balm) are two valuable medicinal plants from Lamiaceae family. Considering the therapeutic potential of sage and lemon balm extracts, there is currently great interest to increase the production of biological material and the synthesis of bioactive compounds by different methods. Both micropropagation and gamma irradiation represent efficient methods of stimulating the synthesis of bioactive compounds in plants. In order to produce biological material, it is important to establish the doses of gamma radiation that do not have a phytotoxic effect on plants. The aim of the present study was to evaluate the effect of different doses of gamma irradiation (100, 300, and 500 Gy) on sage and lemon balm by quantifying of some biochemical compounds (assimilatory pigments, soluble carbohydrates, and total polyphenols) in in vitro plants. The results obtained revealed that high doses of gamma radiation have phytotoxic effect on in vitro raised plants. However, micropropagation is an efficient method to produce high quality biological material, source for obtaining extracts with therapeutic potential.

Efficacy of iron-silver bimetallic nanoparticles to enhance radiotherapy

Radiotherapy (RT) is one of the primary cancer treatment methods. Radiosensitizers are used to enhance RT and protect healthy tissue. Heavy metals have been studied as radiosensitizers. Thus, iron oxide and iron oxide/silver nanoparticles have been the main subjects of this investigation. A simple honey-based synthesis of iron (IONPs) and iron-silver bimetallic nanoparticles (IO@AgNPs) were prepared followed by characterization with transmission electron microscope (TEM), absorption spectra, vibrating sample magnetometer (VSM), and X-ray diffraction (XRD). Additionally, Ehrlich carcinoma was induced in 30 adult BALB/c mice and divided into 6 groups. Mice of group G1 were not treated with nanoparticles or exposed to irradiation (control group), and group G2 and G3 were treated with IONPs and IO@AgNPs respectively. Mice of group G4 were exposed to a high dose of gamma radiation (HRD) (12 Gy). Groups G5 and G6 were treated with IONPs and IO@AgNPs followed by exposure to a low dose of gamma radiation (LRD) (6 Gy) respectively. The impact of NP on the treatment protocol was evaluated by checking tumor growth, DNA damage, and level of oxidative stress in addition to investigating tumor histopathology. Additional research on the toxicity of this protocol was also evaluated by looking at the liver’s cytotoxicity. When compared to HRD therapy, combination therapy (bimetallic NPs and LRD) significantly increased DNA damage by about 75% while having a stronger efficacy in slowing Ehrlich tumor growth (at the end of treatment protocol) by about 45%. Regarding the biosafety concern, mice treated with combination therapy showed lower alanine aminotransferase (ALT) levels in their liver tissues by about half the value of HRD. IO@AgNPs enhanced the therapeutic effect of low-dose radiation and increased the efficacy of treating Ehrlich tumors with the least amount of harm to normal tissues as compared to high radiation dosage therapy.

Gamma Rays as Modifiers of the Compressive and Flexural Properties of Polyester Polymer Concrete

To improve the mechanical and thermal properties of materials, alternative posttreatments have been proposed. One of these posttreatments is based on the use of ionizing radiation. This work studied the effects of gamma rays on the mechanical and thermal properties of polymer concrete (PC) produced with 80% silica sand and 20% polyester resin. High gamma irradiation doses (100–500 kGy) were used. Mechanical properties (compressive and flexural strength), and thermal properties (thermal conductivity, specific heat, and thermal diffusivity) were analyzed. The results show that the highest values of compressive and flexural strength and elasticity modulus occur when polymer concrete is irradiated at 400 kGy. The compressive strength of the reference concrete was 51 MPa; this resistance increased to 62 MPa (23% higher) when polymer concrete was irradiated at 400 kGy. The modulus of elasticity increased 12%, from 2.17 to 2.44 GPa, whereas the flexural strength increased from 16.2 to 17.7 MPa (9%). Changes in the thermal properties (mainly the specific heat) were obtained at 100 and 200 kGy doses. The results were related to the surface modifications produced in the irradiated polyester resin (analyzed by scanning electron microscopy) and its chemical structure (studied by Fourier-transform infrared and Raman spectroscopies).