Cobalt-60 Gamma Radiation Research Articles

Gamma, electron beam and X-ray irradiation effects on polymers in an advanced bone cement mixer device

The medical device industry has been investigating ways to increase the use of alternatives to cobalt-60 gamma radiation and ethylene-oxide gas sterilization, such as electron beam (E-beam) and X-ray radiation, due to regulatory and market pressures. One impediment to switching to E-beam or X-ray technology for sterilization is the lack of data on the effects of these radiation sources on medical device polymers. To provide such data this work considers irradiation and testing of a common single-use medical bone cement mixing system, the Stryker Advanced Cement Mixer (ACM®), that is composed of seven polymer materials. The ACM® devices considered here were processed to sterilization-relevant doses (15, 25, 50, and 70 kGy) using three radiation technologies: gamma, E-beam, and X-ray. The system and its polymer components were tested for product functionality, as well as mechanical and visual properties to determine how exposure effects may be influenced by radiation technology and dose level. We found that although there were instances of statistically significant differences in effects between the gamma-irradiated products and those irradiated with E-beam and X-ray, those effects were negligible in terms of retained functionality of the product and retained mechanical properties of the polymer components. Overall, results of this study demonstrate that, for of the effects studied, E-beam and X-ray are viable alternatives to cobalt-60 gamma radiation for sterilization of the polymer-based device investigated.

Effects of gamma-ray irradiation dose and dose rates on the growth and radiosensitivity of soybean varieties Grobogan and Mutiara 1

Abstract Enhancing soybean production can be achieved through plant breeding, utilizing gamma ray radiation mutation techniques to develop superior varieties. Understanding radiosensitivity is crucial for comprehending the impact of radiation on plant morphology and physiology. This study aims to investigate the impacts of varying doses and dose rates of Cobalt-60 gamma radiation on the growth and development of two soybean varieties, Grobogan and Mutiara 1. This study was conducted to understand how varied radiation doses influence growth parameters and to determine the radiosensitivity, LD50 value, in mutants of the Grobogan and Mutiara 1 soybean varieties. The study employed a randomized complete design with two factors. The first factor was radiation dose ranging from 0 to 1000 Gy. The second factor was dose rate, categorized into low dose rate (219.5 Gy/hour) and high dose rate (4470.2 Gy/hour). The results revealed that the LD50 value of Grobogan variety was estimated at 588.56 Gy at a low dose rate and 657.17 Gy at a high dose rate, while the Mutiara 1 variety had an LD50 value estimate of 512.36 Gy at a low dose rate and 514.30 Gy at a high dose rate. The study also found that the gamma ray radiation dose in the seedling phase trial influenced several growth parameters, including germination percentage, seedling height, development of stem nodes, and formation of leaves. Furthermore, field phase trial showed that a range of radiation dose at 100-300 Gy led to an increase in the number of branches in both soybean varieties and plant height in the Grobogan variety. It also resulted in an increase in the production of pods and total weight of seeds in the Mutiara 1 variety. These findings offer valuable insights into optimizing radiation doses for increasing genetic diversity in soybean.

Effects of gamma, electron beam, and X-ray irradiation on the plastic components of a universal bone cement mixer medical device

Due to market and regulatory pressures, many healthcare manufacturers are considering alternatives to cobalt-60 gamma radiation, including accelerator-based electron beam (E-beam) and X-ray radiation for product sterilization. In this work, the effects of irradiation on a representative medical product, comprised of eight distinct polymer materials, were directly compared for three radiation technologies – cobalt-60 gamma, E-beam, and X-ray – at four dose levels (15, 25, 50, and 70 kGy). The objective was to determine how radiation effects (deleterious or beneficial) are influenced by source and dose level, with the specific goal of determining whether E-beam radiation and/or X-ray radiation could be viable alternatives to gamma radiation for device sterilization. The specific product considered is a single-use medical device for orthopedic surgery, the Stryker Instruments MixeVac III bone cement mixer, which is currently sterilized using gamma radiation from cobalt-60 sources. Following ASTM International standards and input from the manufacturer, we characterized the effects of the three radiation sources on product functionality as well as on the mechanical and optical properties of the constituent polymers. Results indicate that although measurable differences in properties between the standard gamma irradiated materials and the alternative E-beam and X-ray irradiated materials were observed, those differences were small. Statistically significant differences were noted in the case of yellowness index for polyvinyl chloride, high-density polyethylene, and polycarbonate, and in the case of tensile elongation at break for high impact polystyrene and polyvinyl chloride. In general, the results of this study support the viability of E-beam and X-ray radiation as alternative options to cobalt-60 gamma radiation for sterilization of Stryker single-use universal bone cement mixer medical devices.

The renoprotective potential of montelukast: a scoping review

Introduction: Kidney damage can result from various factors, leading to structural and functional changes in the kidney. Acute kidney injury (AKI) refers to a sudden decline in kidney function, while chronic kidney disease involves a gradual deterioration lasting more than 3 months. Mechanisms of renal injury include impaired microcirculation, inflammation, and oxidative stress. Cysteinyl-leukotrienes (CysLTs) are inflammatory substances contributing to tissue damage. Montelukast, a leukotriene receptor antagonist, has shown potential renoprotective effects in experimental models of kidney injury. Methods: The authors conducted a scoping review using PubMed, Scopus, and Web of Science databases to identify relevant studies investigating the impact of montelukast on renal diseases. Articles published until 2022 were included and evaluated for quality. Data extraction and analysis were performed based on predetermined inclusion criteria. Results: The scoping review included 30 studies from 8 countries. Montelukast demonstrated therapeutic effects in various experimental models of nephrotoxicity and AKI induced by agents such as cisplatin, lipopolysaccharide, diclofenac, amikacin, Escherichia coli, cyclosporine, methotrexate, cobalt-60 gamma radiation, doxorubicin, and cadmium. Studies involving human subjects with nephrotic syndrome, pyelonephritis, and other renal diseases also reported positive outcomes with montelukast treatment. Montelukast exhibited anti-inflammatory, anti-apoptotic, antioxidant, and neutrophil-inhibiting properties, leading to improved kidney function and histopathological changes. Conclusions: Montelukast shows promise as a renoprotective medication, particularly in early-stage kidney injury. Its ability to mitigate inflammation, oxidative stress, and neutrophil infiltration contributes to its therapeutic effects. Further research is needed to explore the clinical applications and mechanisms underlying the renoprotective action of montelukast.

Multiscale Modeling of Plutonium Radiation Chemistry in Nitric Acid Solutions. 1. Cobalt-60 Gamma Irradiation of Pu(IV).

Careful manipulation of the plutonium oxidation states is essential in the study and utilization of its rich redox chemistry. To achieve this level of control, a comprehensive mechanistic understanding of radiation-induced plutonium redox chemistry is critical due to the unavoidable exposure of plutonium to ionizing radiation fields, both inherent and from in-process applications. To this end, we have developed an experimentally evaluated multiscale computer model for the prediction of gamma radiation-induced Pu(IV) redox chemistry in concentrated nitric acid solutions (1.0, 3.0, and 6.0 M). Under these acidic, aqueous solution conditions, cobalt-60 gamma irradiation afforded marginal net conversion of Pu(IV) to Pu(VI), the extent of which was dependent on the concentration of HNO3 and absorbed gamma dose. Multiscale calculations, which are in excellent agreement with experimental data, indicate that this observation is due to a combination of inherent plutonium disproportionation reactions and several radiation-induced processes, including redox cycling between Pu(IV) and Pu(III), as achieved by the reduction of Pu(IV) by nitrous acid and hydrogen peroxide, the oxidation of Pu(III) by nitrate and hydroxyl radicals, and the sequential oxidation of Pu(IV) to Pu(V) and Pu(VI) by the remaining available yield of nitrate radicals.

Mechanism of improving anaerobic fermentation performance of kitchen waste pretreated by ionizing irradiation-part 1: rice.

Ionizing irradiation, as a new pretreatment method for the anaerobic fermentation of organic pollutants, is featured with fast reaction speed, good treatment effect, no need to add any chemical reagents, and no secondary pollution. This study explores the mechanism of improving anaerobic fermentation performance of rice samples pretreated by cobalt-60 gamma irradiation through the influence on fermentation substrate, acidogenic phase and methanogenic phase. The results reveal that the soluble chemical oxygen demand of the irradiated rice sample at an absorbed dose of 9.6 kGy increases by 12.4 times due to the dissolution of small molecules of fat-soluble organic matter. The yield of biogas in the acidogenic phase increases by 22.2% with a slight increase in hydrogen gas content. The yield of biogas and methane gas content in the methanogenic phase increases by 27.3% and 15%, respectively. Microbial genome analysis, performed with MiSeq high-throughput sequencing and metagenomic methods, suggests the microbial abundance and metabolic functions in the anaerobic fermentation process change significantly as a result of the pretreatment by gamma irradiation.

PERTUMBUHAN TANAMAN KEDELAI (GLYCINE MAX L.) HASIL RADIASI SINAR GAMMA CESIUM-137

The study of the Effect of Cesium-137 Gamma Ray Radiation on the Growth of Soybean Plants (Glycine max L.) aims to determine the quality of growth of soybean plants (Glycine max L.). The Cesium-137 source was used as a source of irradiation in the study, with a constant distance (x) of irradiation of 100 cm from the wall, with dose variations of 0 Control, 25 mGy, 50 mGy, 75 mGy, 100 mGy and 120 mGy. The method used in this research is descriptive statistical analysis. The samples used in this research are soybean seeds from the Langkowa Soybean plantation, Tonasa Village, Tombolopao Subdistrict and packaged soybeans taken from the packaging seeds of Flower Seed Shop Jl. Veteran Selatan No.395. The results of this study showed that the sprout growth time with a dose treatment of B5 (75 mGy) took 9 days to grow, the percentage of stem height (cm) at a dose of B5 (75 mGy) the average stem height was 3.7 cm, the percentage of leaf width (cm) at a dose of B4 (100 mGy) the average leaf width was 2.9 cm, the percentage of the number of leaves (sheets) at a dose of B3 (75 mGy) the average number of leaves was 4 sheets. The use of Cesium-137 and Cobalt-60 Gamma radiation in plant breeding can be utilised on various types of plants to increase plant cultivation and better production results.

Optically Stimulated Luminescence in LiF–MgF2 system and its response as medical radiation dosimeter

Optically Stimulated Luminescence (OSL) based dosimeters are garnering attention in the field of radiation dosimetry due to a number of benefits like portable equipment, easy and efficient excitation and read out process, re-readability of the dose etc.. Though varieties of fluoroperovskites have been studied as OSL materials, no research on LiMgF3 (Lithium Magnesium Fluoride) as an OSL material has yet been conducted. In the current work, LiF–MgF2 system with a low effective atomic number was synthesized using the high temperature solid state reaction approach and its OSL dosimetry properties were investigated. The prepared sample was thoroughly characterized by employing a variety of techniques, such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and UV–Vis (ultraviolet–visible) spectrophotometry. The structure of the sample was found to be polycrystalline with size in the micrometre range. OSL properties of LMF have been investigated for different doses of gamma and beta along with related OSL kinetic parameters. It exhibits good dose linearity under blue stimulation for gamma (100 mGy - 700 Gy) and beta (30 mGy - 5Gy) radiation. We have also investigated the reusability (3%), reproducibility (2–3%), and fading (45% in 40 days) of the phosphor. To check the viability of the sample in radiation dosimetry under medical treatment in radiotherapy, various dosimetric properties were studied in Linear Accelerator (LINAC) x-rays in MV energy range and Cobalt-60 gamma radiation. These studies include the response of the phosphor to various energies (called energy dependence), field size effect, the effect of the dose rate of the radiation beam, and relative depth dose response. The overall response of the phosphor (comparable with ion chamber in RT experiments) makes the material a potential candidate to be used as an OSL phosphor in medical radiation dosimetry.

The Radioprotectant, BIO 300, Protects the Lungs from Total-Body Irradiation Injury in C57L/J Mice.

Acute exposure to high dose radiation can cause acute radiation syndrome (ARS), a potentially life-threatening illness. Individuals that survive ARS are at risk of developing the delayed effects of acute radiation exposure, with the lungs being particularly susceptible (DEARE-lung). For individuals at risk of radiation exposure, there are no Food and Drug Administration-approved medical countermeasures (MCMs) for prophylactic or post-exposure use that can prevent or mitigate DEARE-lung. BIO 300 is a novel formulation of synthetic genistein that has been extensively studied as a prophylactic MCM for the hematopoietic subsyndrome of ARS (H-ARS). Here, we used a C57L/J mouse model of total-body irradiation (TBI) to investigate whether prophylactic administration of BIO 300 is able to prevent animals from developing DEARE-lung. Oral and parenteral formulations of BIO 300 administered prior to TBI were compared against standard of care, PEGfilgrastim, administered shortly after radiation exposure, and the combination of oral BIO 300 administered prior to TBI and with PEGfilgrastim administered post-exposure. All animals were exposed to 7.75 Gy cobalt-60 gamma-radiation and the primary endpoint was lung histopathology at 180 days post-TBI. Animals treated with BIO 300 had a significant reduction in the incidence of interstitial lung inflammation compared to vehicle groups for both the oral (0% vs. 47%) and parenteral (13% vs. 44%) routes of administration. Similar results were obtained for the incidence and severity of pulmonary fibrosis in animals treated with oral BIO 300 (incidence, 47% vs. 100% and mean severity score, 0.53 vs. 1.3) and parenteral BIO 300 (incidence, 63% vs. 100% and mean severity score, 0.69 vs. 1.7). PEGfilgrastim alone had no significant effect in reducing the incidence of inflammation or fibrosis compared to vehicle. The combination of oral BIO 300 and PEGfilgrastim significantly reduced the incidence of interstitial inflammation (13% vs. 46%) and the severity of pulmonary fibrosis (mean severity score, 0.93 vs. 1.6). Results in the C57L/J mice were compared to those in CD2F1 mice, which are less prone to lung injury following total-body irradiation. Taken together, these studies indicate that BIO 300 is a promising MCM that is able to prophylactically protect against DEARE-lung.

Effect of gamma irradiation on structural, morphological, optical and thermal properties of Ca doped CuO nanostructure thin films

Semiconductor optoelectronic and photonic devices are used in many harsh environment applications such as space and nuclear reactor etc. Gamma radiation in such environments significantly interacts with the semiconductor materials used in these devices, changing their structural, optical, morphological and thermal properties. Therefore, it is vital to investigate the gamma radiation effect of the material to be exposed to radiation in terms of the performance and lifetime of the application. In this study, nanostructured thin films were produced by doping different ratios (0, 0.3, 1.25, 2.5 and 5 mg/mL) of Ca to the copper oxide (CuO) is a semiconductor used in optoelectronic and photonic devices. The thin films produced were deposited on the glass substrate by the spin coating method. The effects of gamma rays on the structural, morphological, optical and thermal properties of the films were investigated by irradiating with different doses (1, 5, 15, 50, 100 and 150 kGy) used a Cobalt-60 gamma radiation source. The structural, morphological, optical and thermal properties of Ca doped CuO nanostructured thin films were investigated by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), atomic force microscope (AFM), mechanical profilometer, UV-Vis spectrophotometry (UV-Vis) and thermogravimetric differential thermal analyzer (TG/DTA). The band gap of thin films were been calculated using Tauc’s plot. The obtained results showed that high-dose gamma radiation caused defects in undoped and Ca doped CuO nanostructured thin films and affected their structural, morphological, thermal and optical properties. Despite the resulting defects, Ca doped CuO nanostructured thin films showed higher absorption intensity and thermal stability against gamma rays. These results showed that Ca doped CuO nanostructured thin films are suitable for many harsh environment applications such as space and nuclear reactors.

Determination of Lethality Curve for Cobalt-60 Gamma-Radiation Source in Rhesus Macaques Using Subject-Based Supportive Care.

Well-characterized and validated animal models are required for the development of medical countermeasures (MCMs) for acute radiation syndrome to mitigate injury due to high doses of total- or partial-body irradiation. Animal models used in MCM development must reflect a radiation dose- and time-dependent relationship, clinical presentation, and pathogenesis of organ injuries in humans. The objective of the current study was to develop the lethality curve for the Armed Forces Radiobiology Research Institute high level cobalt-60 gamma-radiation source in nonhuman primates (NHPs) after total-body irradiation. A dose-response relationship was determined using NHPs (rhesus macaques, N = 36, N = 6/radiation dose) irradiated with 6 doses in the range of 6.0 to 8.5 Gy, with 0.5 Gy increments at a dose rate of 0.6 Gy/min. Animals were provided subject-based supportive care including blood transfusions and were monitored for 60 days postirradiation. Survival was the primary endpoint of the study and the secondary endpoint included hematopoietic recovery. The lethality curve suggested LD30/60, LD50/60, and LD70/60 values as 5.71, 6.78, and 7.84 Gy, respectively. The results of this study will be valuable to provide specific doses for various lethalities of 60Co-gamma radiation to test radiation countermeasures in rhesus macaques using subject-based supportive care including blood transfusion.

Radiolytic Gas Production from Aluminum Coupons (Alloy 1100 and 6061) in Helium Environments-Assessing the Extended Storage of Aluminum Clad Spent Nuclear Fuel.

Corrosion of aluminium alloy clad nuclear fuel, during reactor operation and under subsequent wet storage conditions, promotes the formation of aluminium hydroxide and oxyhydroxide layers. These hydrated mineral phases and the chemisorbed and physisorbed waters on their surfaces are susceptible to radiation-induced processes that yield molecular hydrogen gas (H2), which has the potential to complicate the long-term storage and disposal of aluminium clad nuclear fuel through flammable and explosive gas mixture formation, alloy embrittlement, and pressurization. Here, we present a systematic study of the radiolytic formation of H2 from aluminium alloy 1100 (AA1100) and 6061 (AA6061) coupons in “dry” (~0% relative humidity) and “wet” (50% relative humidity) helium environments. Cobalt-60 gamma irradiation of both aluminium alloy types promoted the formation of H2, which increased linearly up to ~2 MGy, and afforded G-values of 1.1 ± 0.1 and 2.9 ± 0.1 for “dry” and “wet” AA1100, and 2.7 ± 0.1 and 1.7 ± 0.1 for “dry” and “wet” AA6061. The negative correlation of H2 production with relative humidity for AA6061 is in stark contrast to AA1100 and is attributed to differences in the extent of corrosion and varying amounts of adsorbed water in the two alloys, as characterized using optical profilometry, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction techniques.

Development of Live Attenuated Salmonella Typhimurium Vaccine Strain Using Radiation Mutation Enhancement Technology (R-MET).

Salmonella enterica is a leading cause of food-borne diseases in humans worldwide, resulting in severe morbidity and mortality. They are carried asymptomatically in the intestine or gallbladder of livestock, and are transmitted predominantly from animals to humans via the fecal-oral route. Thus, the best preventive strategy is to preemptively prevent transmission to humans by vaccinating livestock. Live attenuated vaccines have been mostly favored because they elicit both cellular and humoral immunity and provide long-term protective immunity. However, developing these vaccines is a laborious and time-consuming process. Therefore, most live attenuated vaccines have been mainly used for phenotypic screening using the auxotrophic replica plate method, and new types of vaccines have not been sufficiently explored. In this study, we used Radiation-Mutation Enhancement Technology (R-MET) to introduce a wide variety of mutations and attenuate the virulence of Salmonella spp. to develop live vaccine strains. The Salmonella Typhimurium, ST454 strain (ST WT) was irradiated with Cobalt60 gamma-irradiator at 1.5 kGy for 1 h to maximize the mutation rate, and attenuated daughter colonies were screened using in vitro macrophage replication capacity and in vivo mouse infection assays. Among 30 candidates, ATOMSal-L6, with 9,961-fold lower virulence than the parent strain (ST454) in the mouse LD50 model, was chosen. This vaccine candidate was mutated at 71 sites, and in particular, lost one bacteriophage. As a vaccine, ATOMSal-L6 induced a Salmonella-specific IgG response to provide effective protective immunity upon intramuscular vaccination of mice. Furthermore, when mice and sows were orally immunized with ATOMSal-L6, we found a strong protective immune response, including multifunctional cellular immunity. These results indicate that ATOMSal-L6 is the first live vaccine candidate to be developed using R-MET, to the best of our knowledge. R-MET can be used as a fast and effective live vaccine development technology that can be used to develop vaccine strains against emerging or serotype-shifting pathogens.

In vitro selection of blackberry (Rubus fruticosus 'Tupy') plants resistant to Botrytis cinerea using gamma ray-irradiated shoot tips.

Blackberry is an economically important crop in Mexico, and its yield is substantially reduced by gray mold, a disease caused by Botrytis cinerea. One of the means to obtain B. cinerea-resistant plants is gamma irradiation. Shoot tips of in vitro-micropropagated blackberry plants (Rubus fruticosus 'Tupy') were irradiated with five doses of Cobalt-60 gamma radiation (0, 15, 30, 45, and 60 Gy) and cultured on Murashige and Skoog basal medium containing 1.0 mg l-1 benzylaminopurine and 0.06 mg l-1 indole-3-butyric acid (MSB medium). After 28 days of culture, survival was evaluated to determine mean lethal dose (LD50), and 200 shoots were further irradiated at the determined LD50 (30.8 Gy). After 28 days, the surviving shoots were micropropagated on MSB medium for 60 days. Non-irradiated shoots were screened for the in vitro selection of resistant B. cinerea, exposing them to different concentrations of sterile culture filtrate of B. cinerea (0, 2, 4, 6, 8, and 10 g l-1) for 28 days to determine mean lethal concentration (LC50), and the irradiated surviving shoots were further exposed to the determined LC50 (4.6 g l-1). Three surviving lines (rfgum5, rfgum6, and rfgum17) that did not present changes compared with the control shoots were micropropagated to obtain plantlets, which were further subjected to in vitro resistance assays using detached leaves inoculated with B. cinerea (1×103 spores ml-1). Plants of rfgum5 and rfgum6 mutant lines were highly resistant and presented similar growth to control plants. Therefore, this methodology is useful to obtain B. cinerea-resistant blackberry plants.

Synthesis of poly(N-vinyl pyrrolidone) (PVP) nanogels by gamma irradiation using different saturation atmospheres

Nanogels are internally crosslinked particles of nanometric size used in various fields e.g. as such as carriers in drug delivery systems. They can be produced using ionizing radiation in dilute aqueous solutions. This method is carried out in a pure polymer-solvent system, avoiding the addition of any additives such as monomers, surfactants, catalysts and crosslinking agents and no further purification step is necessary. Poly(N-vinyl pyrrolidone) (PVP K-90) nanogels were prepared by gamma irradiation in an aqueous solution. The samples were prepared in triplicate in multipurpose cobalt-60 gamma irradiator using 1, 10, 25 and 100 mM PVP solutions. Samples were irradiated in argon and nitrous oxide conditions with doses from 1 kGy up to 25 kGy with 10 kGy/h dose rate. The mean particle size (Rh) was determined by Dynamic Light Scattering (DLS) and radius of gyration (Rg) and weight-average molecular weight (Mw) by Static Light Scattering (SLS). These samples were morphologically characterized using Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). Samples prepared with 100 mM PVP K-90 solution formed macroscopic gels, in the samples obtained with 25 mM PVP K-90 solution there was a prevalence of intermolecular crosslinking. On the other hand, in the samples generated with 10 mM PVP K-90 solution, there was a predominance of intramolecular crosslinking demonstrated in the tendency to: decrease in the radius of gyration (Rg), in the constancy of the weight-average molecular weight (Mw), in the increase in polymer coil density (ρcoil), in the Rg/Rh ratio (shape factor) around 1.0 indicating homogenous, internally cross-linked spheres, in the high relief spherical structures observed in the AFM images and in the spherical particles with high contrast observed in the TEM images. The saturation of the samples with nitrous oxide doubled formation of hydroxyl radicals, favoring the generation of polymeric radicals. Higher average number of radicals in each macromolecule contributed to the higher number of intramolecular crosslinks.

One-step synthesis of tin oxide nanoparticles in aqueous solution induced by free radicals

Tin oxide nanoparticles of uniform size with around 5 nm distribution were synthesized in the aqueous solution of stannous chloride under an oxidizing environment. The syntheses were carried out with Cobalt-60 gamma radiation in N2O saturated solution, photoirradiation using 300 nm UV lamps as well as normal chemical route in the presence of H2O2 at room temperature under ambient laboratory conditions. The nanoparticles were characterized by XRD, FTIR and Raman spectroscopy, SEM and HRTEM measurements. The synthesis mechanism was investigated through the electron pulse radiolysis studies. It was established that the formation of tin oxide nanoparticles takes place only through the reactions of oxidizing free radicals like OH• or Cl2•- with Sn2+ ions in aqueous solution. The formation of tin oxide was found follow similar pathways in all the three cases, except that it took a longer time in the case of normal chemical route as compared to the other two routes. The size and shapes of the nanoparticles were found to be identical in all these three cases.

Gamma-tocotrienol, a radiation countermeasure, reverses proteomic changes in serum following total-body gamma irradiation in mice

Radiological incidents or terrorist attacks would likely expose civilians and military personnel to high doses of ionizing radiation, leading to the development of acute radiation syndrome. We examined the effectiveness of prophylactic administration of a developmental radiation countermeasure, γ-tocotrienol (GT3), in a total-body irradiation (TBI) mouse model. CD2F1 mice received GT3 24 h prior to 11 Gy cobalt-60 gamma-irradiation. This dose of radiation induces severe hematopoietic acute radiation syndrome and moderate gastrointestinal injury. GT3 provided 100% protection, while the vehicle control group had 100% mortality. Two-dimensional differential in-gel electrophoresis was followed by mass spectrometry and Ingenuity Pathway Analysis (IPA). Analysis revealed a change in expression of 18 proteins in response to TBI, and these changes were reversed with prophylactic treatment of GT3. IPA revealed a network of associated proteins involved in cellular movement, immune cell trafficking, and inflammatory response. Of particular interest, significant expression changes in beta-2-glycoprotein 1, alpha-1-acid glycoprotein 1, alpha-2-macroglobulin, complement C3, mannose-binding protein C, and major urinary protein 6 were noted after TBI and reversed with GT3 treatment. This study reports the untargeted approach, the network, and specific serum proteins which could be translated as biomarkers of both radiation injury and protection by countermeasures.

Changes in Growth, Morphology, and Physiology of Tetrahymena pyriformis Exposed to Continuous Cesium-137 and Cobalt-60 Gamma-Radiation.

This study investigated the effects of gamma-radiation on Tetrahymena pyriformis. The experimental approach consists of exposing T. pyriformis growing in presence of Cesium-137 (137Cs) at dose rates of 1, 2, 4, and 6cGyh-1 and Cobalt-60 (60Co) at dose rates of 8, 10, 15, and 20cGyh-1. The radiation doses effects on growth, morphology, some metabolic enzymes, and reactive oxygen species (ROS) markers have been evaluated. When cells were growing in irradiating conditions at dose rates beyond 4cGyh-1, a decreasing of cells and generation numbers with a prolongation of generation time and a change of morphological aspect with rounding-off of cells were observed compared to the control. The 50%-inhibitory dose (ID50) for radiation was estimated at 1568.72 ± 158.45cGy. The gamma-radiation at dose rates more than 6cGyh-1, affected both glyceraldehyde 3-phosphate dehydrogenase and succinate dehydrogenase by inhibiting their activities. All of these effects were more pronounced when cells were irradiated at the dose rate of 20cGyh-1 using 60Co source. For ROS markers generated by gamma-radiation in T. pyriformis, the results showed an increase of the lipid peroxidation in cells grown in presence of gamma-radiation at dose rates more than 6cGyh-1 and an enhancement in catalase and superoxide dismutase activitiesfrom the dose rate of 1cGyh-1. These encouraging results suggested the use of T. pyriformis as a unicellular model cell to investigate other aspects of the response to ionizing radiation.

Use of gamma irradiation for decorative coloring of glass in the Moroccan NIAR facility

The applications that cover the use of ionizing radiation are numerous, very diverse and belong to several fields of activity such as, the medical and agricultural fields etc. The aim of this work is to highlight an application of decorative glass coloring by gamma radiation. Crystal white glass cups are placed on small rotating tables and subjected to exposure to gamma radiation from the cobalt-60 gamma irradiator of the National Institute of Agronomic Research (INRA-Morocco / Tangier) for doses between 0 and 1.5 KGy. The results obtained show the variation in the color of glass between light brown to dark brown depending on the absorbed dose.

Effects of the Cobalt-60 gamma radiation on Pichia pastoris glyceraldehyde-3-phosphate dehydrogenase

Purpose Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key enzyme of the glycolytic pathway, can play a physiological regulatory role and vital other roles in metabolism. This study investigated the effects of gamma radiation generated by Cobalt-60 source on GAPDH activity and protein levels in Pichia pastoris as an eukaryotic organism model. Materials and methods After purification of the GAPDH from P. pastoris, in vitro effects of irradiation to the dose of 2 Gy, using Cobalt-60 at the dose rate of 0.25 Gy/min, on activity and kinetic parameters were investigated. In vivo effects of gamma exposition (dose of 5 Gy) on P. pastoris GAPDH and on reactive oxygen species (ROS) markers were also explored. Results and conclusions The in vitro irradiation of the purified GAPDH reduces the specific activity and the maximum velocity (V max) without alteration of substrates binding (K m). No changes occurred in the specific activity and in kinetic parameters when P. pastoris cells were exposed to Cobalt-60 source. However, this in vivo irradiation of cells produced a significant increase of the GAPDH protein level. The changes of GAPDH activity and the increase of the enzyme population as a target for gamma radiation exposure will play a role in cells adaptation under stress conditions. On the other hand, the increase of malondialdehyde and carbonyl contents and the enhancement of catalase and superoxide dismutase in irradiated cells have been noticed. The antioxidant system can play an important role in the protection of P. pastoris GAPDH against the gamma induced-ROS damage. This is the first report of the P. pastoris GAPDH as a physiological target of gamma exposition.