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为了评估低剂量X射线连续辐射对BALB/c小鼠健康机体免疫系统的影响, 实验采用X射线全身连续照射BALB/c小鼠, 照射第一天剂量为0.07 Gy, 剂量率0.2 Gy/min, 之后每天照射0.08 Gy, 共照射12 d, 累积剂量1.03 Gy, 照射后24和48 h取血、胸腺和脾脏。 流式细胞仪检测免疫细胞周期和凋亡的变化, 胸腺和脾脏指数用重量法获取。 实验结果表明, 小鼠胸腺细胞的周期在照射后24 h被阻滞在G2/M期; 外周血淋巴和胸腺细胞周期48 h被阻滞在 G0/G1期, 细胞凋亡比例在照射后两个时间点都显著增加; 脾脏淋巴细胞周期24 h被阻滞在 G0/G1期, 48 h被阻滞在 S期, 细胞凋亡比例在24和48 h显著减少; 脾脏指数在照射后48 h显著减少。 故低剂量X射线连续全身照射BALB/c小鼠可激活免疫细胞不同的周期监测点, 引起免疫细胞凋亡比例发生变化, 造成一定的辐射损伤, 且这种影响随着免疫器官的不同而不同。 For estimating the effect of low doses X ray continual irradiation to immunity system of mouse, BALB/c mice were continually irradiated to 1.03 Gy by X rays at a dose rate of 0.2 Gy/min in 13 d. At 24 or 48 h after irradiation, the immunocyte cycle and apoptosis were determined by flow cytometry, and the thymus and spleen weights were measured too. The results showed that the cycle of thymocyte were arrested in G2/M at 24 h, the number of peripheral blood lymphocytes and thymocytes in G0/G1 phase at 48 h was up and the percentage of apoptosis had a significance increase in both of time points; the cycle of spleen lymphocytes was delayed in G0/G1 at 24 h, in S phase at 48 h, the apoptosis had a significance decrase at 24 and 48 h; spleen index declined significantly at 48 h. The results suggested that low doses continual X ray whole body irradiation could activate different cell cycle checkpoints, and result in some changes of apoptosis and some damages to immunocytes. The continual X ray irradiation affects the organs differently, it might provide experiment basis for radioprotection. 相似文献
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A total of 40 male and 40 female mice of equal body weight were used in the present study. Whole body gamma (60Co) irradiation was carried out at 400, 800 and 1200 rad. Life span and several parameters of body composition were measured. Cumulative mortality precentage was lower in irradiated females in comparison to males. Ionizing radiation induced reduction (P < 0.01) in body weight, total body water with its two compartments (extra-and intracellular), fat-free body with its component (body cell mass and extracellular tissue), fat-free dry solids with its constituent (body protein and body ash), body potassium and body fat. While all of the above mentioned body composition parameters decreased (P ≤ 0.01) following whole body irradiation, the rations between the body water to these parameters increased (P ≤ 0.01). Sex difference was noticed either for the parameters or for the ratios. 相似文献
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电离辐射质粒pUC18 DNA结构变化的傅里叶变换拉曼光谱分析 总被引:1,自引:0,他引:1
采用傅里叶变换拉曼光谱研究了质粒pUC18DNA经过γ射线电离辐射以后结构的变化。其脱氧核糖-磷酸主链中各振动模式产生的谱带强度有所增加,包括884cm^-1处的脱氧核糖-磷酸主链振动谱带、1460cm^-1处的-CH2弯曲振动谱带和2939cm^-1处的C-H伸缩振动普带。碱基杂环弯曲振动谱带187cm^-1位移到208cm^-1处,强度明显减弱。在3298cm^-1处出现了一个源于N-H伸缩振动的新谱带。此结果表明碱基受损,主链断裂,超螺旋旋结构部分解旋。 相似文献
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Using electron paramagnetic resonance (EPR), we investigated stable radical-production cross sections (σ) of sucrose and L-alanine radicals produced by heavy-ion irradiations with various linear energy transfers (LET). The heavy-ion
irradiation results were compared with those of X-ray irradiation at the same dose. The EPR signal areas for the two compounds
showed a linear relation with the absorbed dose, as well as a logarithmic correlation with the LET. Further analysis was carried
out for the radical-production cross section, which showed that stable radicals of the two compounds were produced through
collisions of several particles with a single molecule. The relative σ value of sucrose for C ion irradiation was (1.29 ± 0.64) × 10−12 μm2. The σ value of alanine for C ion irradiation was (6.83 ± 0.42) × 10−13 μm2. Considering the structural molecular sizes of sucrose and alanine, the σ values are similar. In addition, a comparison of the EPR results for the C ions and X-rays at 50 Gy dose was made. Sucrose
spin concentrations produced by C ions at the LET value of 13.1 keV/μm and X-rays were similar unlike alanine. Thus, the noble
EPR results with X-ray and heavy-ion irradiations imply that sucrose can be useful as a radiation indicator. 相似文献
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脉冲微波辐照影响心肌细胞膜蛋白构象及其机制的研究 总被引:2,自引:3,他引:2
应用显微傅里叶变换红外光谱技术研究了脉冲微波辐照对心肌细胞膜蛋白质构象、功能的影响和相关分子机制。结果表明,辐照可对心肌细胞的细胞膜蛋白质结构产生明显影响。细胞膜脂质中—CH2—、磷脂结构中CO、蛋白质酰胺Ⅰ,Ⅱ带的伸缩振动峰消失或位移。辐照后心肌细胞膜蛋白质二级结构也出现明显变化,α-螺旋和β-折叠结构减少,二级结构无序化程度增加。上述变化均与辐照剂量呈正相关。结果提示受脉冲微波辐照后,心肌细胞膜蛋白构象的完整性受损,膜稳定性及流动性下降,膜上多种生物活性结构被破坏,上述变化构成了细胞膜功能丧失、细胞形态和结构损伤、细胞凋亡等病理学效应的生物化学基础。文章首次从蛋白质构象角度阐述了微波辐照对心肌细胞膜损伤的分子病理机制。 相似文献
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Ivanov Yu. F. Klopotov A. A. Potekaev A. I. Laskovnev A. P. Teresov A. D. Tsvetkov N. A. Petrikova E. A. Krysina O. V. Ivanova O. V. Shugurov V. V. Shegidevich A. A. Kulagina V. V. 《Russian Physics Journal》2017,60(1):175-180
Russian Physics Journal - It is reported that irradiation of the film/substrate system (Zr–Ti–Cu)/(A7) with a high-intensity electron beam is followed by the formation of a multi-phase... 相似文献
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The coefficient of X-ray reflection from a bent Bragg mirror is obtained on the basis of the principle of locality. The focusing
of X-ray quanta by bent crystals is considered. The caustics for the X-rays reflected from the bent Bragg mirror are determined. 相似文献
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为探讨高温高能离子辐照碳化硅后的结构和力学性能随剂量的变化,应用拉曼光谱和纳米压痕技术研究了122 MeV的20Ne4+离子梯度多剂量辐照后的4H-SiC。研究表明,SiC的相对拉曼强度随剂量的增大呈指数规律下降,并出现了代表无序化Si-C键和同核Si-Si键的散射峰。基于DI/DS模型的初步拟合表明,在低剂量范围内扩展缺陷簇是引起SiC无序化的主要因素,高剂量范围内的无序化则是由离子直接碰撞过程的非晶化和扩展缺陷簇共同引起。辐照后的SiC硬度取决于位错钉扎和共价键断裂的共同作用,在0~4.00 dpa之间硬度随剂量增大而增大,在4.00~8.05 dpa之间硬度随剂量增大而减小,剂量在8.05 dpa时,硬度相比于未辐照区域略高,此时共价键断裂和位错钉扎达到平衡。 相似文献
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A. Seeger 《Physics letters. A》1976,58(7):481-483
Small-angle scattering of annealed electron-irradiated copper shows that isolated monovacancies persist through recovery stage III. The scattering appearing at small angles after annealing between 260 K and 300 K can be accounted for by the condensation of self-interstitials to form small dislocation loops. 相似文献
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Hamid Latif M. Shahid Rafique M. Khaleeq-ur-Rahaman Abdul Sattar S. Anjum A. Usman 《辐射效应与固体损伤》2013,168(11):942-953
Laser-induced plasma is used as an X-ray source for the growth of hillocks like nanostructures on platinum surface. To generate X-rays, plasma is produced by Nd:YAG laser, which is operated at second harmonics (λ?=?532?nm, E?=?400?mJ). Analytical grade 5?N pure Al, Cu and W are used as laser targets for X-rays production. X-rays produced from Al, Cu and W plasmas are used to irradiate three analytical grade (5?N pure) platinum substrates, respectively, under the vacuum ~10?4 torr. XRD analysis shows considerable structural changes in the exposed platinum. The decrement in reflection intensities, increment in dislocation line density, change in d-spacing and disturbance in the periodicity of planes evidently prove these structural changes. Atomic force microscope AFM topographic analysis of the platinum exposed to X-rays emitted from Al, Cu and W targets showed that nanometer-size hillocks are produced on the platinum surface irrespective of the source. It has also been observed that due to these hillocks, the roughness of the surface has increased. Conductivity of hillocks produced from X-rays produced by Al, Cu and W targets is compared and it is shown that the hillocks produced by Al target X-rays have better conductivity compared to the hillocks produced by X-rays from Cu and W targets. 相似文献
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应用不对称性参量对周期量级强激光脉冲下原子电离分布的反演不对称性进行了定量分析.采用非微扰的散射理论解析方法和三个激光模式模拟超短脉冲,研究不对称性参量随激光强度、包络位相和脉冲宽度的变化.计算表明,这种不对称性是随着波包的绝对位相以正弦形式变化而变化,其最大不对称程度依赖于脉冲强度和脉冲宽度.随着激光强度的提高,不对称性参量是先降低到最小值然后增加.对脉冲宽度相对长、有几个周期量级的高强度激光,其不对称性具有显著的特点.因此,提高脉冲强度有助于对包络绝对位相变化的观察. 相似文献
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F. Lappe 《Journal of Physics and Chemistry of Solids》1961,20(3-4):173-176
Single crystals of yellow PbO were grown and irradiated by CuK radiation. By comparing the X-ray induced photocurrents with the light induced photocurrents the average energy necessary to produce an electron-hole pair in PbO by X-ray was determined to be 8 eV. 相似文献
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The influence of X-ray irradiation and the following bleaching on microhardness and dislocation mobility was investigated. It was found that dislocations were pinned in irradiated samples and the pinning was not destroyed by illumination. The microhardness, increased by irradiation, increased still further by bleaching. 相似文献
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R. Lewinski C. Graf B Langer R. Flesch H. Bresch B. Wassermann E. Rühl 《The European physical journal. Special topics》2009,169(1):67-72
Recent progress from experiments on clusters and free nanoparticles is reported, where emphasis is put on studies in the soft
X-ray regime. We review selected examples on the characterization of free molecular clusters and nanoparticles. Specifically,
we discuss recent progress in changes of the local structure in free clusters. Photoemission and particle charging as well
as elastic light scattering from free nanoparticles are reported. These approaches permit the characterization of the intrinsic
properties of nanoscopic systems as building blocks of nanoscopic matter and possible nanomaterials. 相似文献