Characteristics of pulsed photo-stimulated luminescence and thermoluminescence for the identification of gamma irradiated poultry eggs

Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.     

Improvement of carbon fiber surface properties using electron beam irradiation

Carbon fiber-reinforced advance composites have been used for structural applications,mainly on account of their mechanical properties.The main factor for a good mechanical performance of carbon fiber-reinforced com- posite is the interfacial interaction between its components,which are carbon fiber and polymeric matrix.The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite.EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests.Experimental results showed that EB irradiation improved the ten- sile strength of carbon fiber samples.The maximum value in tensile strength was reached using doses of about 250 kGy.After breakage,the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated.SEM micrographs showed modifications on the carbon fiber surface.     

Preparation and preliminary evaluation of [^55Co]（II）vancomycin

Co-55 （t1/2=17.53 h） was produced by 150 uA irradiation of a natural nickel target using 15 MeV protons. It was separated from the irradiated target material by two ion exchange chromatography steps with a radiochemical yield of 〉95% and was used for the preparation of [^55Co]vancomycin （[^55Co]VAN）. Optimization studies were performed using Co-57 due to its longer half-life. Cobalt-57 （t1/2=271.79 d） was produced by irradiation of a natural nickel target with 150 pA current of 22 MeV protons. The 57Co was separated from the irradiated target material using a no-carrier-added method with a radiochemical yield of 〉97%. Both products were controlled for radionuclide and chemical purity. The solutions of [^55Co]VAN were prepared （radiochemical yield〉80%） starting with 55Co acetate and vancomycin at room temperature after 30 min. A precise solid phrase extraction （SPE） method was developed using Si Sep-Pak in order to purify/reconstitute the final formulation for animal studies. [^55Co]VAN showed a radiochemical purity of more than 99%. The resultant specific activity was about 1.15 TBq/mmol. It is proved that the tracer is stable in the final product and in presence of human serum at 37℃ up to 24 h. Biodistribution study of [55Co]VAN in normal rats was undertaken for up to 72 h.     

Level of natural radionuclides in foodstuffs and resultant annual ingestion radiation dose

The natural radioactivities in three major groups of foodstuff widely consumed in Upper Egypt were determined. The specific activities of ^226Ra, ^232Th, and ^40K in cereals, leguminosae, and flour were measured using γ-ray spectroscopy. Another group of hay, water, and soil samples from the same location were also analyzed. Hay samples were found to contain the highest radioactivity concentration among all the samples that were investigated. This increment could be due to the high water content in the shoots which tends to accumulate soluble radionuclides. The average calculated concentrations of soil samples in the present study exhibits the lowest values with respect to those from different countries. In the case of water samples, the average activities of both ^232Th and ^40K were similar to those for soil while ^226Ra was twice that of water sample. The annual ingestion dose from each radionuclide was calculated. The computed annual dose owing to daily intake of radium, thorium, and potassium via wheat flour, lentils, and bean in the present study （214.8 μSv） is ten times lower than the global average annual radiation dose （2400 μSv） from the natural radiation sources as proposed by UNSCEAR. The obtained results show that the dose values are quite low and carry insignificant radiation dose to the public.     

Sterilization of Turmeric by Atmospheric Pressure Dielectric Barrier Discharge Plasma

In this study atmospheric pressure dielectric barrier discharge （DBD） plasma has been employed for sterilizing dry turmeric powders. A 6 kV, 6 kHz frequency generator was used to generate plasma with Ar, Ar/Ou, He, and He/O2 gases between the 5 mm gap of two quartz covered electrodes. The complete sterilization time of samples due to plasma treatment was measured. The most important contaminant of turmeric is bacillus subtilis. The results show that the shortest sterilization time of 15 rain is achieved by exposing the samples to Ar/O2 plasma. Survival curves of samples are exponential functions of time and the addition of oxygen to plasma leads to a significant increase of the absolute value of time constant of the curves. Magnitudes of protein and DNA in treated samples were increased to a similar value for all samples. Taste, color, and solubility of samples were not changed after the plasma treatment.     

Biological effects of implantation and penetration of nitrogen ion beams on wheat seeds

The biological effects of wheat seeds irradiated by 48MeV/u and 20MeV/u ^14N^7 beams are studied,respectively.The results show.both penetration and implantation of heavy ions can significantly inhibit growing pwer(height of plant stem)of wheat seeds.The greater dose is ,the weaker growing power is,and the implantation influence on growing power is stronger than the penetration;a great variety of chromosomal aberrations were observed in root tip cells of irradiated seeds and the aberration frequencies were several hundred times higher than that of the corresponding control;it has been proved by 3H-TdR incorporation test that unscheduled DNA synthesis exists in irradiated wheat seed embryos.It is found by ESR spectroscopy that the variation of free radical concentration with total dose has different features for the pentrated and implanted seeds.     

Effects of thermal aging on Fe ion-irradiated Fe–0.6%Cu alloy investigated by positron annihilation

Thermal aging effects on surface of 2.5 Me V Fe ion-irradiated Fe–0.6%Cu alloy were investigated using positron annihilation techniques. The samples were irradiated at 573 K to a dose of 0.1 dpa. Their thermal aging was performed at 573 K for 5, 50 and 100 h. From the results of Doppler broadening measurement, an obvious trough could be seen in near-surface region from the S parameters and inflection point form at S–W curves. This indicates changes in the annihilation mechanism of positrons in surface region after thermal aging. Coincident Doppler broadening indicates that the density of Cu precipitates in the thermal aged samples decreased, due to recovery of the vacancies.     

Optimization Study of Pulsed DC Nitrogen-Hydrogen Plasma in the Presence of an Active Screen Cage

A glow discharge plasma nitriding reactor in the presence of an active screen cage is optimized in terms of current density,filling pressure and hydrogen concentrations using optical emission spectroscopy（OES）.The samples of AISI 304 are nitrided for different treatment times under optimum conditions.The treated samples were analyzed by X-ray diffraction（XRD） to explore the changes induced in the crystallographic structure.The XRD pattern confirmed the formation of iron and chromium nitrides arising from incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of treatment time（h）.The results showed clear evidence of improved surface hardness and a substantial amount of decrease in the treatment time compared with the previous work.     

Genotoxic Effects of Superconducting Static Magnetic Fields （SMFs） on Wheat （Triticum aestivum） Pollen Mother Cells （PMCs）

The effects of superconducting static magnetic fields （SMFs） on the pollen mother cells （PMCs） of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities （0, 1, 3, 5 and 7 Tesla） for 5 h or different durations （1, 3 and 5 h） at a magnetic flux density of 7 Tesla. The seeds were germinated at 23℃ after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus （MN）, chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity （below 5 Tesla） showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.     

Instrumental neutron activation analysis of beachrock samples of South East Coast of Tamilnadu, India

Element profiles of some beach rock samples collected from South East Coast of Tamilnadu, India have been determined using single comparator method of INAA. The geo-chemical behavior of the elements in the region is discussed. The irradiations were done at thermal neutron flux of ~ 1011 cm-2·s-1 at 20kW power using Kalpakkam Mini Reactor (KAMINI), IGCAR, Kalpakkam, Tamilnadu, India. Around 19 elements have been determined from 15 samples by high-resolution gamma spectrometry. The accuracy and precision were evaluated by assaying the irradiated Standard Reference Material (SRM 1646a Estuarine sediment) and were found to be in good agreement with certified values.     

Thermoluminescence properties of irradiated chickpea and corn

A study was carried out to establish a detection method for irradiated chickpea and corn by thermoluminescence (TL) method. The leguminous were packed in polyethylene bags and then the packets were irradiated at room temperature at different doses by ⁶⁰Co gamma source at 1, 4, 8 and 10 kGy. Minerals extracted from the leguminous were deposited onto a clean aluminum disc and TL intensities of the minerals were measured by TL. It was observed that the extracted samples from both leguminous exhibit good TL Intensity and the TL intensity of glow curves of them increased proportionally to irradiation doses. The TL glow curve of both irradiated leguminous presents a single broad peak below 400 °C. The TL trapping parameters glow peaks were estimated by the additive dose (AD), T_m(E_a)-T_stop and computerized glow curve deconvolution (CGCD) methods. The fading characteristics of glow curves were also recorded up to 6 months.     

Effect of γ-ray irradiation on Nd–Fe–B alloys

We report on how γ-ray irradiation affects the magnetic properties of a powder sample of Nd–Fe–B, which was irradiated at room temperature with doses up to 700 kGy. Both the magnetic properties and surface morphology were changed by the effects of the γ-ray irradiation. The unirradiated and irradiated samples were then characterized using the VSM, XRD and SEM techniques.     

Investigation of the stability of the radiation sensitivity of TL peaks of quartz extracted from tiles

One of the most important mineral in dosimetric investigation is quartz, which is found abundantly in archaeological and geological materials. Although there are many studies about its thermoluminescence (TL) properties in the literature, it may exhibit different properties for each quartz mineral extracted from the different region of the world. In the present work, the stabilities and dose responses of glow peaks of quartz obtained from the tiles of Kubad Abad Palace in central Turkey were investigated after annealing at 500 and 600 °C for 1 h. The variation of radiation sensitivity of TL peaks of the quartz grains extracted from tiles are found to be more stable after annealing at 600 °C than 500 °C for 1 h. The TL dose responses of glow peaks of annealed and unannealed quartz samples were also studied up to approximately 3 kGy. It was observed that the pre-irradiation heat treatments affect the dose response behaviors of glow peaks.     

Thermoluminescence properties of isostructural K2YF5 and K2GdF5 crystals doped with Tb in response to α, β and X-ray irradiation

The thermoluminescence (TL) properties of isostructural fluoride K₂YF₅ and K₂GdF₅ crystals doped with Tb³⁺ of different concentrations have been studied in the temperature range from 30 to 500 °C after α, β and X-ray irradiation. Strongly different structures of TL glow curves following α or β irradiation have been found for Tb³⁺ doped K₂YF₅ for all studied concentrations of Tb³⁺ whereas for K₂GdF₅ crystals the different TL curves after α or β irradiation are detected only for heavily doped samples. On the other hand, all the studied materials show similar TL glow curves after β or X-ray irradiation. It has been discovered that K₂YF₅ doped with 1 at.% Tb³⁺ has TL radiation sensitivity to β irradiation of the same order as that of the well known TLD-100 (LiF:Mg,Ti) phosphor and much higher sensitivity to α irradiation. The TL mechanism in K₂YF₅ and K₂GdF₅ doped with Tb³⁺ is discussed by taking into account the TL emission spectra from irradiated samples, which are identical to the emission spectra of the Tb³⁺ ions in these hosts under photo-excitation, and the kinetics parameters obtained with the method of various heating rates.     

35种辐照食品人体食用安全性评价研究

本文报道了人体90天期间食用35种辐照食品的观察结果。试验对象为70名学医学生和8名职工,随机配对分为试验组(食用辐照食品)和对照组(食用品种相同的普通膳食)。辐照食品包括粮食(大米、面粉、赤豆、黄豆、花生仁)、肉制品(香肠、牛肉干)、蔬菜(马铃薯、卷心菜、黄芽菜、芋艿、茭白、胡萝卜、蘑菇、冬笋、乌笋、茹菇、花菜、刀豆、萝卜、青椒、扁豆、冬瓜、蕃茄、毛豆、荸荠、藕、姜)、水果(桔子、苹果)、干果(红枣、桂园、莲心)和其它品种(黄花菜、腐竹),共计35种。辐照吸收剂量为0.1～0.8KGy,剂量不均匀性(最大吸收剂量/最小吸收剂量)为1.34～1.40。辐照食品占总膳食中重量比例为60.3％。实验采用严格的双盲法。90天观察表明:试食者乐意接受,对健康无不良影响,也未见到临床体检、血象、尿常规、血液生化、肝功能、肾功能、内分泌、免疫、多项致突变指标(外周血淋巴细胞染色体数量畸变与结构畸变、姊妹染色单体交换、微核测定、尿Ames试验)等有明显改变。因而认为在本实验条件下辐照食品对人体是安全的。     

含抗氧剂的辐射交联LDPE的熔融与结晶行为

含有不同抗氧剂的ＬＤＰＥ在空气中、室温下经受２００ＫＧｙ的电子束辐照处理后，和未加抗氧剂的试样比较，凝胶分数下降６％－３０％。ＤＳＣ测定表明，辐照试样的熔点和熔融热焓、结晶温度与结晶热比未辐照试样略有降低。相同组成的试样两次升温和降温ＤＳＣ测定结果指出，熔点和结晶温度不变，但熔融和结晶热焓呈下降趋势。降温ＤＳＣ分析还发现，辐照不影响所研究的ＬＤＰＥ试样中支链分布的嵌段性质。     

Effect of absorbed dose and storage length on electron paramagnetic resonance （EPR） signal strength in irradiated alfalfa seeds

1 Introduction Human salmonellosis associated with the con- sumption of alfalfa seed sprouts has been documented in several countries and people have applied several techniques to kill microorganisms in the alfalfa seeds[1]. Gamma irradiation can effectively kill the microorganisms in the seeds over a certain range of absorbed dose[2]. As a prerequisite, a suitable detection method for distinguishing whether or not a kind of food has been irradiated lies not only in whether some differences be…     

Microstructural evolution of the China Low Activation Martensitic (CLAM) steel irradiated by H and He ion beams

China Low Activation Martensitic (CLAM) steel was irradiated at room temperature with different doses of He⁺ and H⁺ ion beams. TEM indicated that the microstructure of unirradiated CLAM steel consisted of laths, grain boundaries, dislocations and carbides. Electron diffraction patterns revealed that the microstructure of carbides at grain boundaries was primarily dominated by M₂₃C₆ carbide. Vacancy clusters were induced into the matrix after irradiation. TEM-EDX of carbides and matrices of unirradiated and post-irradiated samples were performed to investigate the composition of carbides and the effect of irradiation on the composition of carbides. Carbides from unirradiated and irradiated specimens at grain boundaries were found to be enriched with Cr. For irradiated specimens, concentrations of Cr increased as the irradiation dose was increased. Cr enrichment could lead to precipitation of additional phase.     

含纤维素辐照食品的ESR法研究

60Co发出的γ射线于0,0.5,1.0,3.0,5.0,10.0kGy剂量范围对干燥的红辣椒粉、花生和提取出的草莓籽进行了辐照处理,用电子自旋共振(Electron spin resonance,ESR)来分析研究信号强度与辐照剂量的关系以及相关性R2.结果表明,三种样品的ESR信号与剂量正相关,其中草莓的ESR信号随剂量增长最慢,红辣椒粉的计算最为精确,花生的次之.含纤维素辐照食品的剂量与ESR信号关系清晰,可作为建立ESR方法检测辐照食品的方法.