Alterations of immune functions induced by 12C6+ion irradiation in mice

Purpose: To estimate the biological risks to the immune system of the type of space radiation, 12C6+, encountered by cosmonauts during long-term travel in space. Materials and methods: The Kun-Ming strain mice were whole-body irradiated by 12C6+ ion with 0, 0.01, 0.05, 0.075, 0.2, 0.3, 0.5, 0.75, 1 or 2 Gy, at a dose rate of 1 Gy/min. At 35 days after irradiation, the thymus and spleen weights were measured, the natural killer (NK) cells activity of spleen was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), and the interferon-gamma (IFN-gamma) levels in serum and thymus were detected with enzyme-linked immunosorbent assays (ELISA). Results: The results showed that the thymus weight, IFN-gamma levels in serum and the activity of splenic NK-cells had significantly increased at a dose of 0.05 Gy. With further dose increase, the weight of spleen continued to increase but the weight of thymus, IFN-gamma level and NK-cells activity declined. Conclusions: These results suggest that the dose of 0.05 Gy irradiation has a stimulatory effect on mouse immunity; this effect declined with increasing dose.

Alleviation of pre-exposure of mouse brain with low-dose C-12(6+) ion or Co-60 gamma-ray on male reproductive endocrine damages induced by subsequent high-dose irradiation

Irradiation has been widely reported to damage organisms by attacking on proteins, nucleic acid and lipids in cells. However, radiation hormesis after low-dose irradiation has become the focus of research in radiobiology in recent years. To investigate the effects of pre-exposure of mouse brain with low-dose C-12(6+) ion or Co-60 gamma (gamma)-ray on male reproductive endocrine capacity induced by subsequent high-dose irradiation, the brains of the B6C3F(1) hybrid strain male mice were irradiated with 0.05 Gy of C-12(6+) ion or Co-60 gamma-ray as the pre-exposure dose, and were then irradiated with 2 Gy as challenging irradiation dose at 4 h after pre-exposure. Serum pituitary gonadotropin hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), testosterone, testis weight, sperm count and shape were measured on the 35th day after irradiation. The results showed that there was a significant reduction in the levels of serum FSH, LH, testosterone, testis weight and sperm count, and a significant increase in sperm abnormalities by irradiation of the mouse brain with 2 Gy of C-12(6+) ion or Co-60 gamma-ray. Moreover, the effects were more obvious in the group irradiated by C-12(6+) ion than in that irradiated by Co-60 gamma-ray. Pre-exposure with low-dose C-12(6+) ion or Co-60 gamma-ray significantly alleviated the harmful effects induced by a subsequent high-dose irradiation.

Adaptive hormetic response of pre-exposure of mouse brain with low-dose C-12(6+) ion or Co-60 gamma-ray on growth hormone (GH) and body weight induced by subsequent high-dose irradiation

The brain of the Kun-Ming strain mice were irradiated with 0.05 Gy of C-12(6+) ion or Co-60 gamma-ray as the pre-exposure dose, and were then irradiated with 2 Gy of 12C6+ ion or Co-60 gamma-ray as challenging irradiation dose at 4 h after per-exposure. Body weight and serum growth hormone (GH) concentration were measured at 35th day after irradiation. The results showed that irradiation of mouse brain with 2 Gy of C-12(6+) ion or Co-60 gamma-ray significantly diminished mouse body weight and level of serum GH. The relative biological effectiveness values of a 2 Gy dose of C-12(6+) ion calculated with respect to Co-60 gamma-ray were 1.47 and 1.34 for body weight and serum GH concentration, respectively. Pre-exposure with a low-dose (0.05 Gy) of C-12(6+) ion or Co-60 gamma-ray significantly alleviated reductions of mouse body weight and level of serum GH induced by a subsequent high-dose (2 Gy) irradiation. The data suggested that low-dose ionizing irradiation can induce adaptive hormetic responses to the harmful effects of pituitary by subsequent high-dose exposure.

Germ cell loss induced by C-12(6+) ion irradiation in young female mice

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of C-12(6+) ion in the Bragg peak or the plateau region. At 10th day after irradiation, ovarian and uterine weights were measured: normal and atretic (identified with the oocyte to be degenerating or absent) primordial, primary and preantral follicles were identified in the largest cross-section of each ovary. Percentage (%) of normal follicles of each developmental stage of oogenesis was calculated. The data showed that compared to controls, there was a dose-related decrease in percentage of normal follicles in each developmental stage. And the weights of ovary and uterus were also reduced with doses of irradiation. Moreover, these effects were much more significant in the Bragg peak region and the region close to the Bragg peak than in the beam's entrance (the plateau region). Radiosensitivity varied in different follicle maturation stages. Primordial follicles, which are thought to be extremely sensitive to ionizing irradiation, were reduced by 86.6%, while primary and preantral follicles reduced only by 72.5% and 61.8% respectively, by exposure with 6 Gy of C-12(6+) ion in the Bragg peak region and the region close to the Bragg peak. The data suggested that due to their optimal depth-dose distribution in the Bragg peak region, heavy ions are ones of the best particles for radiotherapy of tumors located next of vital organs or/and surrounded by normal tissues, especially radiosensitive tissues such as gonads.

Temperature annealing of tracks induced by ion irradiation of graphite

Highly oriented pyrolytic graphite (HOPG) samples were irradiated by Xe ions of initial kinetic energy of 3 MeV/u. The irradiations were performed at temperatures of 500 and 800 K. Scanning tunneling microscopy (STM) images show that the tracks occasionally have elongated structures under high-temperature irradiation. The track creation yield at 800 K is by three orders of magnitude smaller compared to that obtained during room-temperature irradiation. STM and Raman spectra show that amorphization occurs in graphite samples irradiated at 500 K to higher fluences, but not at 800 K. The obtained experimental results clearly reveal that the irradiation under high temperature causes track annealing.

Radio-resistance induced by nitric oxide to heavy ion irradiation in A172 human glioma cells

To investigate effects of nitric oxide on cellular radio-sensitivity, three human glioma cell lines, i.e. A172, A172 transfected green fluorescence protein (EGFP) gene (EA172) and A172 transfected inducible nitric oxide synthesis (iNOS) gene (iA72), were irradiated by C-12(6+) ions to 0, 1 or My. Productions of nitric oxide and glutathione (GSH) in A172, EA172 and iA172 were determined by chemical methods, cell cycle was analyzed by flow cytometry at the 24th hour after irradiation, and survival fraction of the cells was measured by colorimetric MTT assay at the 5th day after irradiation. The results showed that the concentrations of nitric oxide and GSH in iA172 were significantly higher than in A172 and EA172; the G(2)/M stage arrest induced by the C-12(6+) ion irradiation was observed in A172 and EA172 but not in iA172 at the 24th hour after exposure; and the survival fraction of iA172 was higher than that of EA172 and iA172. Data suggest that the radio-sensitivity of the A172 was reduced after the iNOS gene transfection. The increase of GSH production and the change of cellular signals such as the cell cycle control induced by nitric oxide may be involved in this radio-resistance.

重离子诱变技术选育碱性蛋白酶高产菌株；The Selection for High-yield Alkaline Protease Producing Strain by Heavy-ion Irradiation

从采集的土壤样品中分离筛选出一株碱性蛋白酶产生菌G-41,经16S rRNA分子鉴定为芽孢杆菌属菌株。该菌株在发酵培养基中能产生较高产量的胞外碱性蛋白酶(1.7×104U/mL)。以G-41为出发菌株,对其进行重离子辐照诱变处理,获得突变株G-41-68,将该突变株再次经重离子诱变,从大量突变株中筛选出碱性蛋白酶高产菌株15Gy-54,其酶活力达到6.22×104U/mL。与出发菌株相比较,突变株G-41-68和15Gy-54的酶活力分别提高了1.58倍和2.65倍。对突变株15Gy-54的发酵条件进行了优化研究,结果表明,该菌株的碱性蛋白酶活力得到进一步提高,达到7.18×104U/mL,其最适发酵条件为:培养基(g/100mL)为胰蛋白胨1、酵母膏0.5、乳糖5、Na2HPO4·12H2O0.4、KH2PO40.03、Na2CO30.1、MgSO40.0481(4×10-3mol/L)、pH8.0,培养温度41℃,振荡培养时间42-48h。实验结果表明,重离子辐照诱变技术是一种非常有效的微生物诱变育种新技术。

Preparation of Microporous Membranes by Swift Heavy Ion Irradiation and Impedance Characterization

Polypropylene (PP) microporous membranes were successfully prepared by swift heavy ion irradiation and track-etching. Polypropylene foils were irradiated with Au-197 ions of kinetic energy 11.4 MeV.u(-1) (total energy of 2245.8 MeV) and fluence 1x10(8) ions.cm(-2) at normal incidence. The damaged regions produced by the gold ions along the trajectories were etched in H2SO4 and K2Cr2O7 solutions leading to the formation of cylindrical pores in the membranes. The pore diameters of the PP microporous membranes increased from 380 to 1610 nm as the etching time increased from 5 to 30 min. The surface and cross-section morphologies of the porous membranes were characterized by scanning electron microscopy (SEM). The micropores in the membranes were found to be cylindrical in shape, homogeneous in distribution, and equal in size. Some mathematical relations of the porosity of the PP microporous membranes were established by analytic derivation. The microporous membranes were used in lithium-ion batteries to measure their properties as separators. The electrical conductivity of the porous membrane immersed in liquid electrolyte was found to be comparable to that of commercial separators by electrochemical impedance spectroscopy (EIS). The results showed that the porosity and electrical conductivity were dependent on the ion fluence and etching time. By adjusting these two factors, microporous membranes with good porosity and electrical conductivity were made that met the requirements for commercial use.

重离子辐照制备电池用微孔膜及其阻抗性质；Preparation of Microporous Membranes by Swift Heavy Ion Irradiation and Impedance Characterization

利用离子辐照结合径迹蚀刻方法制备聚丙烯(PP)微孔膜.用加速器产生的单核能为11.4MeV·u-1(总能量2245.8MeV)的197Au离子束辐照PP膜,剂量为1×108ions·cm-2.辐照后PP膜沿离子路径产生损伤区域,用硫酸与重铬酸钾的混合液进行蚀刻(5-30min),制备出孔径为380-1610nm的聚丙烯微孔膜.对膜的表面和断面形貌进行表征,微孔膜的孔径大小及空间分布均匀,孔道上下贯通,形状近似为圆柱形.给出了微孔膜的孔隙率理论公式.将制备的聚丙烯微孔膜用作锂离子电池隔膜,用电化学阻抗谱(EIS)测定浸满电解液的微孔膜的离子电导率,并与商用隔膜进行比较.分析表明辐照剂量和孔径大小均会影响膜的孔隙率和离子电导率,选择合适的辐照剂量和蚀刻时间,可以制备出孔隙率和离子电导率符合应用标准的聚丙烯微孔膜.

生防菌BJ1离子辐照突变高效菌株筛选及对黄瓜枯萎病的生防效果；Screening of Mutation High-Yielding Biocontrol Bacterium BJ1 by Ion Beam Irradiation and Effect of Controlling Fusarium oxysporum cucunerinum Disease

枯草芽孢杆菌BJ1是一种在真菌病害防治中发挥重要作用的生防因子,为进一步提高它的抑菌能力,获得生防效果更好的高效菌种,利用不同能量和剂量的12C6+对生防菌BJ1进行了离子辐照处理。研究结果表明:离子辐照生防菌BJ1的最适宜剂量为200~400 Gy,传能线密度(LET)为60 keV/μm;突变菌株的抑菌能力比BJ1提高了2%~21%;不仅防病效果比BJ1提高了17.48%,而且对植物具有更好的促生长作用。

利用重离子辐照技术制备锂离子电池隔膜；Preparation Lithium-ion Battery Separator by Swift Heavy Ion Irradiation Methods

用能量11.4MeV/u和注量1×108ions/cm2的197Au离子垂直辐照聚丙烯薄膜,通过电导测量法监测温度、硫酸浓度和重铬酸钾浓度对径迹蚀刻速率的影响,得到合适的蚀刻条件;成功制备出孔径范围在600—1000nm的重离子径迹聚丙烯孔膜,并用场发射扫描电镜对孔的形状及孔径大小进行了表征,对孔洞锥角的形成进行了分析,为重离子辐照技术制备锂离子电池隔膜提供了实验数据。

Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

Yeast strain Saccharornyces cerevisiae was irradiated with different doses of 85 MeV/u Ne-20(10+) to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Cy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T-->G and T-->C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

94MeV Xe离子辐照引起的薄膜硅光学带隙变化研究；Modification of Optical Bandgap of Thin Silicon Films Induced by 94 MeV Xe Ion Irradiation

室温下,用94MeV的Xe离子辐照纳米晶和非晶硅薄膜以及单晶硅样品,辐照量分别为1.0×1011,1.0×1012和1.0×1013ions/cm2。所有样品均在室温下用UV/VIS/NIR光谱仪进行检测分析。通过对比研究了纳米晶、非晶、单晶硅样品的光学带隙随Xe离子辐照量的变化。结果表明,不同结构的硅材料中Xe离子辐照引起的光学带隙变化规律差异显著:随着Xe离子辐照量的增加,单晶硅的光学带隙基本不变,非晶硅薄膜的光学带隙由初始的约1.78eV逐渐减小到约1.54eV,而纳米晶硅薄膜的光学带隙则由初始的约1.50eV快速增大至约1.81eV,然后再减小至约1.67eV。对硅材料结构影响辐照效应的机理进行了初步探讨。

~(12)C离子束辐照对酵母发酵能力的影响；Improved ethanol fermentation of a yeast mutant by C-12 ion beam irradiation

利用100MeV/u的12C6+离子束辐照酵母Saccharomyces cerevsiea YY,选育出一株高产突变菌株C03A,考察C03A发酵过程中不同温度、pH、糖汁浓度对发酵的影响。通过正交实验确定最佳发酵条件为:糖汁浓度24%、温度35℃、pH5.0。在10L发酵罐实验中,C03A发酵速率相对原始菌株高,36h发酵完全,比原始菌株缩短12h;发酵产酒率达到13.2%(V/V),比原始菌株高1.6%(V/V)。

Molecular vibration spectroscopy study of irradiation effect in C-60 films induced by low energy ion

Irradiation effect in C-60 films induced by 170 keV B ion was investigated by means of Fourier transform infrared (FTIR) and Raman spectroscopies. The damage cross section sigma and the effective damage radius R are deduced from the experimental data of all four IR active modes and evident four Raman active modes of C-60 molecule. The differences on irradiation sensitivity and structural stability of the different active modes of C-60 molecule are compared. The results indicate that T-1u (4) of infrared active mode and A(g) (1) of Raman active mode are most sensitive for B ion irradiation. On the other hand T-1u (2) of infrared active mode and H-g (3) of Raman active mode are comparatively stable under B ion irradiation. (C) 2010 American Institute of Physics. [doi:10.1063/1.3512968]