Low-Dose Gamma Radiation Fields Decrease Cell Viability, Damage DNA, and Increase the Expression of Hsp70 and p53 Proteins in Human Leukocytes

Ionizing radiations are tools in diagnosis and treatment of diseases. Leukopenia from exposure to ionizing radiation has been reported. Due to their radiosensitivity, leukocytes are a biological model to analyze cell damage. Therefore, cell viability, DNA damage, and Hsp70 and p53 expression in human leukocytes exposed to low-dose gamma radiation fields from a 137Cs source were evaluated. A decrease in cell viability, DNA damage and an increase in the expression of Hsp70 and p53 proportional to the radiation dose received was found, which was 0.2, 0.4, 0.6, 0.8 and 1.0 mGy.

Nerve regeneration following implantation of axotomized nerves pretreated with gamma radiation

BACKGROUND： It has been shown that irradiation to the neurolemma can reduce immuuogenicity. However, it is still poorly understood whether the degenerated nerve can affect peripheral nerve regeneration OBJECTIVE： To observe the effect of radiation-damaged nerve transplantation on functional recovery of the peripheral nerve. DESIGN, TIME AND SETTING： Self-control animal trial was performed at the Experimental Center of Orthopedics, Tangdu Hospital of Fourth Military Medical University from January to October 2005. MATERIALS： Fifty-four healthy, Chinese rabbits, irrespective of gender, were randomly divided into experimental （n = 36） and control （n = 18） groups. A 60 Co Y -radiation machine and NDI-200 nerve electromyograph were provided by the Experimental Center of Orthopedics, Tangdu Hospital of Fourth Military Medical University. METHODS： A median incision was made in the posterior right thigh of rabbits after abdominal anesthesia. A 30-mm segment of sciatic nerve was excised from the inferior margin of the piriform muscle to the tibiofibular intersection. The sciatic nerve in the experimental group was sterilely radiated with 350 Gy for 9.5 minutes. The damaged nerve segment was then re-transplanted. In the control group, the sciatic nerve was re-transplanted directly following excision. Nerve conduction velocity was determined at 4, 6, and 8 months post-surgery. MAIN OUTCOME MEASURES： Functional assessments, such as gait, nutritional status of skin on dorsum of foot, toe spreading reflex, and foot holding, were made between 1 and 180 days post-surgery. The common peroneal nerve and tibial nerve reflexes under clamping were observed at 4, 6, and 8 months post-surgery to evaluate functional restoration of the peripheral nerve. Electromyogram was performed to observe nerve conduction velocity. RESULTS： From postoperative days 1 to 26, the limbs that were transplanted with irradiated nerve exhibited dragged walking, foot drop, sole ulcers, depilation, self-induced injury to the toes, and other denervation behaviors. From 95 to 120 days after re-transplantation, the ulcers recovered, in addition to recovered toe-spreading reflex. When subjected to the clamping text, nerve reflex occurred. Compared with animals transplanted with normal nerve, nerve conduction velocity in the experimental group was slower at 4 and 6 months post-surgery （P 〈 0.05 and P 〈 0.01）. At 8 months after surgery, nerve conduction velocity recovered in the experimental group, but was still slower than the control group （P 〈 0.05）. Recovered conduction velocity in the experimental group was significantly faster than the control group （P 〈 0.05）. CONCLUSION： Reinnervation was achieved by pre-treating a 30-mm segment of sciatic nerve with 350-Gy radiation. Although radiation improved nerve conduction velocity recovery following re-transplantation, the velocity was not completely recovered to normal levels.

Influence of ^(60)Co gamma radiation on fluorine plasma treated enhancement-mode high-electron-mobility transistor

A1GaN/GaN depletion-mode high-electron-mobility transistor （D-HEMT） and fluorine （F） plasma treated enhancement-mode high-electron-mobility transistor （E-HEMT） are exposed to 60Co gamma radiation with a dose of 1.6 Mrad （Si）. No degradation is observed in the performance of D-HEMT. However, the maximum transeonductance of E-HEMT is increased after radiation. The 2DEG density and the mobility are calculated from the results of capacitance-voltage measurement. The electron mobility decreases after fluorine plasma treatment and recovers after radiation. Conductance measurements in a frequency range from 10 kHz to 1 MHz are used to characterize the trapping effects in the devices. A new type of trap is observed in the F plasma treated E-HEMT compared with the D-HEMT, but the density of the trap decreases by radiation. Fitting of Gp/w data yields the trap densities DT = （1-3）Х1012 cm^-2.eV^-1 and DT = （0,2-0.8）Х10^12 cm^2-eV^-1 before and after radiation, respectively. The time constant is 0.5 ms-6 ms. With F plasma treatment, the trap is introduced by etch damage and degrades the electronic mobility. After 60Co gamma radiation, the etch damage decreases and the electron mobility is improved. The gamma radiation can recover the etch damage caused by F plasma treatment.

Comparative Study of Micro and Nano Size WO3/E44 Epoxy Composite as Gamma Radiation Shielding Using MCNP and Experiment

The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles： micro and nano with sizes of i #m and 5Onto, respectively. The simulation results show that W03 nano particles exhibit a larger increase in linear attenuation coefficient in comparison with micro size particles. Finally, validation of simulation results with the published experimental data shows a good agreement.

Effect of the Substitution of Sand by Rubber of Waste Tires on the Mechanical Properties of Hydraulic Concrete and Exposure to Gamma Radiation

For a long time and until now, rubber is the most used material for the manufacture of tires for motor vehicles. Unfortunately, once the tire meets its life cycle, the remaining rubber cannot be recycled, so the tires are discarded in collection centers and often in clandestine dumps. This represents a serious environmental problem because, in one case, these waste tires become breeding grounds for insects and wildlife that is harmful to humans. In the second case, the tires are burned, releasing highly damaging gases into the atmosphere. On the other hand, concrete is worldwide the construction material par excellence. It is basically composed of cement, gravel and sand. Mixing these three components in different proportions, their mechanical strength in compression can be increased. However, due to its fragile nature, concrete, once a crack is formed, it rapidly advances by fragmenting the material and producing its rapid collapse. In the present work, in order contribute to the care of the environment as well as to modify the fracture mode of the concrete, rubber particles obtained from waste tires were used as sand substitute in hydraulic concrete. In addition, rubber modified samples concrete were lately exposed to 70 kGy of gamma radiation in order to study the effects of this radiation on the mechanical deformation of concrete. The results showed a decrease in the mechanical properties of the concrete with rubber particles with respect to the traditional concrete itself. However, such decreases were offset by the fact that samples with rubber addition do not collapses as fast as the free rubber samples. The acquired data pave the way for research with great benefits, such as the use of recycled tires in concrete for its fracture mode modification in a beneficial way, as well as a possible decrease in the cost of concrete.

Evaluation of the Use of Gamma Radiation for Reduction of Aflatoxin B1 in Corn(Zea mays)Used in the Production of Feed for Broiler Chickens

Corn is one of the main grasses used to produce human or animal food. One of the main problems with the use of corn is the presence of mycotoxins, where aflatoxin B1 is one of the most harmful for human and animal health. Chemical methods such as the addition of antifungals and sequestrants are used to control this contaminant in food;however, these methods can leave dangerous residues. The aim of this research was to evaluate the effectiveness of irradiation with gamma rays on corn for the control of aflatoxin B1. For this purpose, three treatments were compared: treatment 1, application of gamma radiation, treatment 2, application of antifungal and treatment 3, combination of gamma radiation and application of antifungal. Corn without exposure to any control of aflatoxin was used as a witness group. Irradiation doses of 2, 6 and 10 kGy were tested, and the dose of 6 kGy was selected as the best since it lowered aflatoxin B1 more effectively. The corn analyzed in this study was stored during 45 days at 23°C, and every 15 days. We determined the concentration of aflatoxin B1, presence or absence of pathogenic microorganisms and insects, and we evaluated the physicochemical characteristics of the grain. Then, the treatments were compared and treatment 1, only irradiation with gamma rays, proved to be significantly more effective in the reduction of aflatoxin B1 and the total inhibition of the survival of the insects during the 45 days of storage which allowed better preservation of the protein. All treatments controlled the growing of pathogenic microorganisms as Salmonella and Enterobacteriacea, and kept the humidity of the grain in values lower than 13%. The cost production of a bag of 40 kg of feed was also estimated in USD 22.56;which is1.80% greater than the cost corresponding to the conventional process that uses mycotoxin sequestrants.

^(60)Co gamma radiation effect on AlGaN/AlN/GaN HEMT devices

The testing techniques and experimental methods of the 60Co gamma irradiation effect on A1GaN/A1N/ GaN high electron mobility transistors （HEMTs） are established. The degradation of the electrical properties of the device under the actual radiation environment are analyzed theoretically, and studies of the total dose effects of gamma radiation on A1GaN/A1N/GaN HEMTs at three different radiation bias conditions are carried out. The degradation patterns of the main parameters of the A1GaN/A1N/GaN HEMTs at different doses are then investigated, and the device parameters that were sensitive to the gamma radiation induced damage and the total dose level induced device damage are obtained.

Study of the Sensing Characteristics of Irradiated Fiber Bragg Gratings and Fabry-Perot Interferometers Under Gamma Radiation

The sensing characteristics of irradiated fiber Bragg gratings(FBGs)and Fabry-Perot interferometers(FPIs)were investigated under a 2MGy dose of gamma radiation.The study found that the pressure sensitivity of FP sensors after irradiation was stable,while the temperature sensitivity of FBG sensors was unstable,and both wavelengths displayed a shift.These findings offer the possibility for the application of FP pressure sensors in the gamma radiation environments,and FBG sensors require further research to be suitable for application in the nuclear radiation environments.

PROBING THE IMPACT OF GAMMA-IRRADIATION ON THE METABOLIC STATE OF NEURAL STEM AND PRECURSOR CELLS USING DUAL-WAVELENGTH INTRINSIC SIGNAL TWO-PHOTON EXCITED FLUORESCENCE

Two-photon excitedfluorescence(TPEF)spectroscopy and imaging were used to investigate the effects of gamma-irradiation on neural stem and precursor cells(NSPCs).While the observed signal from reduced nicotinamide adenine dinucleotide(NADH)was localized to the mitochondria,the signal typically associated with oxidizedflavoproteins(Fp)was distributed diffusely throughout the cell.The measured TPEF emission and excitation spectra were similar to the established spectra of NAD(P)H and Fp.Fpfluorescence intensity was markedly increased by addition of the electron transport chain(ETC)modulator menadione to the medium,along with a concomitant decrease in the NAD(P)H signal.Three-dimensional(3D)neurospheres were imaged to obtain the cellular metabolic index(CMI),calculated as the ratio of Fp to NAD(P)Hfluorescence intensity.Radiation effects were found to differ between low-dose(
50 cGy)and high-dose(50 cGy)exposures.Low-dose irradiation caused a marked drop in CMI values accompanied by increased cellular proliferation.At higher doses,both NAD(P)H and Fp signals increased,leading to an overall elevation in CMI values.Thesefindings underscore the complex relationship between radiation dose,metabolic state,and proliferation status in NSPCs and highlight the ability of TPEF spectroscopy and imaging to characterize metabolism in 3D spheroids.

In Vitro Evaluation of Gamma Irradiation on a Gel Formulation of Cratylia Mollis: Rheological Proporties and Microbiological Control

Lectin Cramoll-1,4, obtained from Cratylia mollis seeds (beans camaratu) was structurally characterized, biologically and pharmacologically, but its use as a biopharmaceutical is not well documented. The objective of this study is to propose a biopharmaceutical formulation lectin Cramoll-1,4, test their hemagglutinating properties in vitro as well as the use of gamma radiation as a continuous process of decontamination formulation. It was made of the extraction and purification Cramoll-1,4, was developed a gel formulation using Carbopol? as a vehicle, at concentrations of 50, 100, 200, 300 and 600 μg was irradiated with 60Co gamma rays in a dose of 7.549 kGy·h–1. The proposed formulation at a concentration of 300 μg produced an increase in the hemagglutinating units Cramoll-1,4 due to the synergistic effect caused by gamma radiation. Considering the diverse use of lectins, specific molecular and structural factors, as well as changes resulting from its formulation, concentration, irradiation and route of administration is of utmost importance to continue the studies in vitro, for subsequent application in vivo to characterize the physiological and molecular processes involved in the response and cellular effects.

GRAFTING ONTO WOOL V.RADIATION-INITIATED GRAFTING OF ACRYLIC ACID ONTO WOOL FIBER

This paper deals with graft copolymerization of acrylic acid (AA) onto Xinjiang fine wool.fiber in aqueous medium initiated by gamma rays. Graft copolymerization was carried out by themutual irradiation method in limited air. Percent grafting and percent efficiency have been deter-mined as a function of total dose, dose rate, concentration of monomer, wool weight and reactiontemperature. Graft copolymers are characterized with infrared (IR) spectroscopy, scanning elec-tron microscopy (SEM), and X--ray diffractometer. Properties of the grafts were studied, and compared with the virgin fiber.

Use of radiation in strains of Saccharomyces cerevisiae:A new technique for industrial applications

During the industrial fermentation process in the production of fuel ethanol, yeasts are subject to several stressing conditions. The survival and the permanence of strains introduced in the process correlate with the capability of these yeasts in resisting to physical and chemical stresses, as well as their recovering ability to compete with contaminating micro-organisms commonly present in this industrial process. We aim at the selection of Saccharomyces cere visiae strains having this capability and ability. In this sense, cultivations of strains with industrial interest were irradiated with gammas ray at a wide dose interval. Growing curves for the strains were analyzed by means of their relative growth, a new concept here introduced, which allows a better understanding of the growing and recovering processes following radiative stress. It was found that gamma radiation could be used as an alternative method to quantify growing capabilities of S. cerevisiae strains under stressing conditions. It was also shown that this radiological method could be utilized as an additional procedure to select best robust industrial strains. This radiological method simplifies traditional analysis of strain viability, by avoiding the great number of necessary and consecutive fermentation assays.

Determination of Gamma Angular Distribution from the Shape of Spectral Line for the First Excited State of Carbon Nucleus

An experiment investigating gamma emission in hadron therapy was performed at Cyclotron Centre Bronowice (CCB), Cracow, Poland, using two different phantom materials—carbon and poly(methyl methacrylate) PMMA. The measurements were carried out at 70 MeV proton beam energy and the gamma quanta were registered with the use of HP Ge detector with scintillation anti-Compton shielding. Although the primary aim was to establish a solid experimental data base for future applications in prompt gamma imaging, the data have also been analyzed with regards to the position and shape of the spectral line stemming from deexcitation of the carbon excited state 4.44 MeV. Measurements potentially useful to determine the cross section were performed only at 90° laboratory polar angle. However, benefiting from the very good energy resolution it turned out possible to extract information on angular distribution of the C* (4.44 MeV) deexcitation by analyzing the associated line shape. This paper presents the scheme of model calculations assuming the whole process can be divided into two stages: excitation of carbon nuclei by impinging protons and deexcitation of the C* (4.44 MeV) state.

SWELLING BEHAVIOR OF ACRYLAMIDE HYDROGEL IN DIFFERENT SOLVENTS AND pHs

Swelling property of acrylamide hydrogels,prepared from aqueous solutions of acrylamide monomer havingconcentrations in the range of 10-60 wt% by ray irradiation method using a Co-60 gamma radiation source at dosesranging 1-30.0 kGy,has been investigated under various swelling media.These swelling media were basically solvents(solutions),produced by dissolving methanol,ethanol,glucose,sucrose,sodium chloride and sodium persulfate individuallywith distilled water,and solutions prepared with pHs=3,7 and 10.The investigation was performed in order to observe theeffect of these solvents and pHs as well as the influence of monomer concentrations,radiation doses and times on swellingbehavior of hydrogels.Swelling values were found higher for hydrogels prepared with lower monomer concentrations(ca.20 wt%)and radiation doses(ca.5 kGy)and showed a leveling off tendency within 24 h.The glucose solvent and the buffersolution of pH=10 revealed significant increase of swelling of hydrogels as compared to other solutions.Results areexplained based on crosslinking density in hydrogel,polymer-solvent/polymer-polymer interactions in solutions,permeability of molecules in solutions and ionization capacity of hydrogel in pH.

Dark output characteristic of γ-ray irradiated CMOS digital image sensors

The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.

Altitude-dependent distribution of 137Cs in the environment:a case study of Aragats massif, Armenia

This paper considers the distribution of technogenic 137Cs and naturally occurring radionuclides:238 U,232 Th and40 R concentrations in soils and 137Cs in atmospheric dry depositions by altitudinal belts of the Aragats mountain massif,Republic of Armenia.Undisturbed soil samples were collected at altitudes from 1000 to 3200 m.For the determination of geochemical variability,two soil sampling campaigns were undertaken.Atmospheric dry depositions were sampled from five stations at1100-3200 m collected onto organic fiber filters between June and December 2016.137Cs activity was measured using a high-purity Germanium detector coupled to a multichannel analyzer(Canberra).Results indicated that specific activity of 137Cs in soils at 1000 m is495-528 Bq m^-2,andat3200 mis10,500-11,470 Bq m^-2.No correlation observed for 137Cs versus naturally occurring radionuclides,which varies in distribution by altitude.Specific activities of 137Cs in dry atmospheric depositions varies from 1.06 at 846 m to2.37 Bq m^-2 per quarter at 3200 m and increases as the altitude increases.Activities of 137Cs in soil and dry atmospheric deposition correlated significantly,and 137Cs activity in soils and atmospheric dry depositions decrease as the absolute altitude decreases.The 50-year effective dose from exposure to 137Cs fallout varies with altitude from 0.007 to 1.42 m Sv.

Human Adipose Stem Cells Exposed to Gamma Radiation and Inactivity (Stasis) Show Increased Cancer Markers and DNA Damage. A Preliminary Assessment of a Pharmaceutical Formulation to Reverse These Effects and Its Applications for Medical Radiotherapy and the Space Industry

Gamma radiation exposure and physical inactivity occur in medical radiotherapy patients and astronauts resulting in substantial deterioration of their health. At the molecular level, the radiation triggers elevated markers for DNA double-strand breaks and tumorigenicity. Cell stasis is a potential phenomenon associated with low physical activity in recovering cancer patients and astronauts. This preliminary study assessed parameters of stasis and gamma radiation on human adipose stem cells (ADSCs) that have important regenerative functions for the body. A prototype pharmaceutical formulation (PF) was tested to prevent and reverse the effects of radiation and stasis. ADSCs were subjected to short-term (1 - 5 days) and longer-term (8 - 25 days) stasis and radiation with a combined total exposure of alpha, beta and gamma radiation measured at 455 microSv/hr on the Geiger counter. Cell health markers were grouped for characteristics of cellular health (annexin, H2A.X, NO, ROS) and tumorigenicity potential (P13, Ki67, MAPK) that were measured with flow cytometry. Results showed PF to improve cell health in days 1 - 5 compared to stasis (p = 0.01) and radiation (p = 0.02), and PF reduced tumorigenicity compared with stasis (p = 0.018) and radiation (p = 0.03). For longer exposure (8 - 25 days) PF improved cellular health compared with stasis (p = 0.038) and showed a non-significant trend for decreasing radiation effects (p = 0.07). There was decreased tumorigenicity compared with stasis (p = 0.003) and radiation (p = 0.005). This preliminary evaluation of the PF showed it to have 88% (66/75) positive assay results (p < 0.00001 Chi-square) indicating three promising beneficial effects: 1) prevent cell/DNA damage, 2) reduce cancer risk, and 3) recover damaged and precancerous stem cells. The PF could have important applications for medical radiotherapy patients, astronauts and future space mining personnel. PF reduced carcinogenesis and DNA damage of stem cells by approximately 50% from radiation that was the microSievert equivalent of 4 months on board the International Space Station.

BL Lacertae objects and the extragalactic γ-ray background

A tight correlation between γ-ray and radio emission is found for a sample of BL Lacertae （BL Lac） objects detected by the Fermi Gamma-ray Space Telescope （Fermi） and the Energetic Gamma-Ray Experiment Telescope （EGRET）. The γ-ray emission of BL Lac objects exhibits strong variability, and the detection rate of γ-ray BL Lac objects is low, which may be related to the γ-ray duty cycle of BL Lac objects. We estimate the γ-ray duty cycle, δγ ≌ 0.11, for BL Lac objects detected by EGRET and Fermi. Using the empirical relation of γ-ray emission with radio emission and the estimated γ-ray duty cycle δγ, we derive the γ-ray luminosity function （LF） of BL Lac objects from their radio LE Our derived γ-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei （AGN） sample. Comparison of the derived LF of the γ-ray BL Lac objects in this work with that derived by Abdo et al. （2009a） requires the γ-ray duty cycle of BL Lac objects to be almost luminosity-independent. We find that - 45% of the extragalactic diffuse γ-ray background （EGRB） is contributed by BL Lac objects. Combining the estimate of the quasar contribution to the EGRB in the previous work, we find that 77% of the EGRB is contributed by BL Lac objects and radio quasars.

Radiation-induced one-pot synthesis of grafted covalent organic frameworks

Post-synthetic functionalization of covalent organic frameworks(COFs)is an alternative way to enhance and broaden their properties and potential applications.However,the chemical functionalization of COFs is a great challenge because traditional procedures are often time-and energy-consuming,while the crystallinity of COFs can be damaged under harsh conditions.Here we report the in-situ introduction of functional graft chains onto the skeleton of COFs during the synthesis process through the combination of radiation-induced synthesis and graft polymerization techniques under ^(60)Co gamma-ray radiation.The synthesis and functionalization of COFs are simultaneously accomplished in a chemical system under ambient conditions yielding a large number of different functionalized COFs.The obtained carboxyl-functionalized COFs exhibit excellent radioactive uranium removal capabilities from aqueous solution with fast uptake dynamics,high adsorption capacity,and excellent selectivity over other competing metal ions.

Radiation induced color centers in cerium-doped and cerium-free multicomponent silicate glasses

The effect of doped cerium on the radiation-resistance behavior of silicate glass was investigated in our work. The ultraviolet-visible absorption spectra and electron paramagnetic resonance（EPR） spectra were obtained after the cerium-rich and cerium-free multicomponent silicate glasses（K509 and K9） were irradiated by gamma rays with a dose range from 10 to 1000 kGy. The results showed that E’ center, oxygen deficient center（ODC） and non-bridging oxygen hole center（HC1 and HC2） were induced in K9 and K509 glasses after radiation. The concentrations of all color centers presented an exponential growth with the increase of the gamma dose. Moreover, the concentration of HC1 and HC2 in cerium-doped K509 glass was much lower than that in cerium-free K9 glass at the same dose of radiation, which could be attributed to the following mechanism： Ce3＋ ions capturing holes then forming Ce3＋＋ centers inhibited the formation of hole trapped color centers（HC1 and HC2） and Ce4＋ ions capturing electrons to form Ce3＋ centers suppressed the formation of electron trapped color centers like E’ center.