X射线照射后EL-4细胞p16mRNA和P16蛋白表达的变化

采用RT?PCR(逆转录聚合酶链反应)半定量方法检测p16基因转录水平的变化,采用免疫细胞化学方法检测蛋白表达,观察X射线照射对离体培养的EL?4细胞p16基因转录及蛋白表达的影响,证实p16基因转录表达在辐射诱导EL?4细胞G1期阻滞中的重要作用。结果表明,2.0GyX射线照射后2—48h,EL?4细胞p16mRNA水平增高,照射后72h恢复正常水平。P16蛋白表达于照射后2h开始增高,照射后12hP16蛋白表达非常显著高于对照组(p<0.01)。剂量?效应实验表明,0.5—6.0GyX射线照射后12h,?4细胞p16mRNAEL水平明显提高。2.0、4.0、6.0Gy组P16蛋白表达均非常显著增加(分别p<0.01)。研究证实,电离辐射能够诱导EL?4细胞p16基因转录及蛋白表达增高,其增幅呈现明显的剂量依赖性。提示辐射诱导p16基因转录表达增加在辐射诱导EL?4细胞G1期阻滞中发挥重要作用。     

整体照射后胸腺细胞和脾细胞p16基因转录和蛋白表达的变化

研究X射线全身照射对小鼠胸腺细胞和脾细胞p16基因转录及蛋白表达的影响。采用Northern blot检测p16基因转录水平的变化;采用流式细胞术检测蛋白表达的变化。时程结果表明,2.0Gy照射后4-24h,胸腺细胞p16mRNA水平明显增高,8-48h P16蛋白表达显著增高(p<0.05-p<0.01);照射后4-8h脾细胞p16mRNA水平明显增高,24h P16蛋白表达显著增高(p<0.05)。量效结果表明,0.5-6.0Gy照射后,胸腺细胞p16mRNA水平呈剂量依赖性增高,P16蛋白表达在1.0-4.0Gy组明显高于假照射组(p<0.05-p<0.01);脾细胞p16mRNA水平亦增高,但增幅远低于胸腺细胞,P16蛋白表达在1.0-4.0Gy组明显高于假照射组(p<0.05-p<0.01)。X射线全身照射可诱导胸腺细胞和脾细胞p16基因转录及蛋白表达增高。p16表达参与整体照射诱导细胞G1期阻滞的分子调控。     

电离辐射诱导EL-4淋巴瘤细胞G1期阻党政军及相关蛋白的表达

探讨X射线诱导EL－4细胞G1期阻滞及相关蛋白的表达。采用PI荧光标记 ,流式细胞术检测细胞周期的变化。用单克隆抗体免疫荧光标记,流式细胞术检测蛋白表达的变化。结果表明,2．0Gy和4.0Gy照射后12-72h,G1期EL－4细胞百分数显著高于假照射组（P＜0．05－p＜0.001).4.0Gy照射后EL-4细胞p53蛋白表达从照射后2h开始明显增高,持续至照射后24h(p＜0．05－p＜0．001）;p21蛋白表达在照射后2h开始明显增高,持续至照射后48h(p＜0.05-p＜0.001);GADD45蛋白表达在照射后2h开始明显增高,持续至照射后48h(p＜0．05－p＜－0．001）;MDM2蛋白表达在照射后4h开始明显增高,持续至照射后24h（p＜0.05-p＜0.01）。结果提示,中等剂量X射线照射可诱导EL－4细胞G1期阻滞。p53、p21和GADD45蛋白表达在电离辐射诱导EL－4细胞G1期阻滞中起重要作用。     

电离辐射对小鼠胸腺细胞p16、CyclinD1、CDK4表达的影响

采用流式细胞术 (FCM)检测了不同剂量X射线全身照射后 ,昆明种小鼠胸腺细胞p16、CyclinD1、CDK4蛋白表达的时程变化和量效关系。结果表明 ,2GyX射线照射后 8h小鼠胸腺细胞p16表达明显增高 ,2 4h达到峰值 ,持续至照射后 4 8h ,72h降至正常水平 ;CDK4表达水平在照射后8h明显降低 ,12h降至最低 ,照射后 4 8h恢复近正常水平 ;周期蛋白CyclinD1表达轻度下调。不同剂量 (0 .5 - 4Gy)照射后p16蛋白表达随着剂量的增加而增加 ,2Gy组与假照射组相比显著增多 (p<0 .0 1) ;CDK4蛋白表达在 2Gy照射后明显低于假照射组 (p <0 .0 1) ;CyclinD1表达在 0 .5 - 2Gy照射后可见下降趋势。结果提示 :p16 /CyclinD1/CDK4 /pRb通路在电离辐射诱导胸腺细胞G1期阻滞中可能起着十分重要的作用。     

电离辐射诱导P21蛋白表达及对细胞周期解偶联的作用

采用免疫细胞化学方法检测P21蛋白表达的变化。采用P1荧光标记及流式细胞术（Flow cytometry,FCM）测定细胞周期并分析细胞倍体的变化。观察电离辐射对EL-4细胞P21蛋白表达的影响及对细胞周期解偶联的作用。时效实验结果显示,4．0GyX射线照射后2—72h,EL-4细胞中P21蛋白表达明显增高（p〈0．05-p〈0．001）。量效实验结果显示,0．5—6．0GyX射线照射后24h,EL-4细胞中P21蛋白表达明显增高（p〈0．01—p〈0．001）。结果还显示,1．0-16．0GyX射线照射后,EL-4细胞的8倍体细胞数在各剂量组均未见明显变化（均p〉0．05）。研究表明,电离辐射可诱导EL-4细胞P21蛋白表达,但不诱导EL-4细胞周期解偶联。提示P21蛋白可能参与细胞周期解偶联的分子调控。     

电离辐射对小鼠胸腺细胞和脾细胞P53基因mRNA和蛋白表达的影响

采用流式细胞术和Northern blot法检测了不同剂量X射线全身照射后,小鼠胸腺细胞和脾细胞中p53基因mRNA和蛋白表达的变化。结果表明,2．0GyX射线全身照射后,小鼠胸腺细胞p53阳性细胞百分数与对照相比,在照后1h开始升高,8h达最高,以后逐渐下降。不同剂量X射线照射后,小鼠胸腺细胞和脾细胞中p53基因mRNA水平的观测结果表明,75mGy及2.0Gy全身照射后1-48h,小鼠胸腺细胞和脾细胞中p53mRNA水平均未见明显的变化;0.5-6.0GyX射线全身照射后4h,小鼠胸腺细胞和脾细胞中p53 mRNA水平亦未见明显的改变。结果提示,X射线全身照射可诱导小鼠淋巴细胞p53蛋白表达,其p53蛋白表达增加是通过转录后机制实现的。     

电离辐射诱导EL-4淋巴瘤细胞G_1期阻滞及相关蛋白的表达

探讨X射线诱导EL 1细胞G1期阻滞及相关蛋白的表达。采用PI荧光标记 ,流式细胞术检测细胞周期的变化。用单克隆抗体免疫荧光标记 ,流式细胞术检测蛋白表达的变化。结果表明 ,2 0Gy和 4 0Gy照射后 12 72h ,G1期EL 4细胞百分数显著高于假照射组 ( p <0 0 5- p <0 0 0 1)。 4 0Gy照射后EL 4细胞 p53蛋白表达从照射后 2h开始明显增高 ,持续至照射后2 4h ( p <0 0 5- p <0 0 0 1) ;p2 1蛋白表达在照射后 2h开始明显增高 ,持续至照射后 4 8h ( p <0 0 5- p <0 0 0 1) ;GADD4 5蛋白表达在照射后 2h开始明显增高 ,持续至照射后 4 8h ( p <0 0 5- p <0 0 0 1) ;MDM 2蛋白表达在照射后 4h开始明显增高 ,持续至照射后 2 4h ( p <0 0 5- p <0 0 0 1)。结果提示 ,中等剂量X射线照射可诱导EL 4细胞G1期阻滞。p53、p2 1和GADD4 5蛋白表达在电离辐射诱导EL 4细胞G1期阻滞中起重要作用     

4GyX射线照射对EL-4细胞cyclin B1及cdc2 mRNA水平的影响

采用流式细胞术和半定量 RT-PCR 的方法分别检测 4Gy X 射线照射后 EL-4 细胞不同细胞周期时相和EL-4 细胞内 cyclin B1 及 cdc2 mRNA 水平的时程变化,以探讨 X 射线照射诱导 EL-4 细胞 G2 期阻滞的分子调控机制。 结果表明,4Gy X 射线照射 EL-4 细胞后 2h,G2期细胞开始明显增多,4—8h 达峰值(p<0.001)。EL-4 细胞内 cyclin B1 mRNA 水平于照射后 1h 开始下降,24h 降至最低值,为假照组的 57.7 %,72h 恢复至正常水平。EL-4 细胞中 cdc2 mRNA 水平于照射后 12h 开始降低,24—48h 降至最低水平,分别为假照组的59.2% 和 58.9%,72h 恢复至假照组水平。结果提示, 4Gy X 射线照射可诱导 EL-4 细胞 cyclin B1 及 cdc2 mRNA水平明显下降,直接导致 MPF 活性减少是引发 G2 期阻滞的关键。     

X射线全身照射对小鼠脾细胞cyclin B1 和cdc2基因转录水平的影响

采用Northern blot杂交法研究了低、高剂量X射线全身照射后不同时间小鼠脾细胞cyclin B1和cdc2基因转录水平的变化。结果表明,75mGy X射线全身照射后2h及12－24h小鼠脾细胞cyclin B1 mRNA表达量略有升高,分别为假照组的1.25、1.27和1.22倍,48h回降至假照水平;而2.0Gy照射后4h开始下降,12h降至最低,与假照组相比降低了39％,48h恢复至假照组水平。同时观察了cdc2 mRNA表达量的变化,结果表明,与假照组相比75mGy X射线全身照射后2－48h的各时间点小鼠脾细胞cdc2 mRNA表达量未见明显变化;而2．0Gy照射后的时程变化与相同剂量照射后cyclin B1的变化基本一致。结果提示：低剂量辐射可诱导小鼠脾细胞cyclin B1转录水平增高,进而促进其细胞周期进程,但对cdc2转录水平无影响;相反,较高剂量辐射可诱导cyclin B1和cdc2转录水平均明显降低,最终发生G2期阻滞。     

快中子和X射线照射对小鼠肠P53和CyclinB1蛋白表达的影响

采用昆明系小鼠,随机分组,快中子和X射线全身照射后6h处死,Western blot法检测小肠组织中p53和CyclinB1蛋白的表达;流式细胞术(Flow cycometry,FCM)检测小肠细胞周期的变化.结果发现,照射后小肠组织p53蛋白的表达量随着照射剂量增加呈上升趋势;CyclinB1蛋白的表达量先是随照射剂量的增加而升高,中子照射组0.28 Gy时达到高峰,X射线照射组4 Gy时达到高峰,随后逐渐降低;FCM结果显示快中子和X射线照射后,G2/M期细胞数都随照射剂量增高而增多(P＜0.05).以上结果提示低剂量快中子和X射线照射可诱导p53和CyclinB1表达水平的增高,而随着剂量进一步增大可导致CyclinB1表达量的降低,最终发生G2期阻滞.     

Increase in internal friction in uranium with change in temperature

On the basis of the previously described increase in internal friction in uranium during heating, a semiquantitative evaluation was made of the dependence of increase in internal friction on the rate of heating, frequency and amplitude of vibrations. The results of the calculations agree satisfactorily with data obtained experimentally. A study was made of the effect of the initial state of the specimen on the increase in internal friction at the initial stages of heating.     

广东省进出口食品中的放射性检验

报道了广东省商检中心放射性检验室开展的广东进出口食品中的放射性检验工作。介绍了检验工作采用仪器的主要性能及应用;给出了分析测量方法和探测下限以及实验的质量保证措施,并给出了检验室测量的广东省几种食品中的放射性含量范围,测量结果与我国食品中放射性活度变化范围大体一致。     

Tritium concentrations in precipitation in Shanghai

Tritium concentrations in precipitation can be used as a criterion to evaluate the tritium baseline of the environment. The tritium concentration in precipitation in Shanghai during 2014-2015 was determined. Values ranged from 0.68 ± 0.04 to 4.11 ± 0.39 Bq/L, and it showed a decreasing trend compared with historical data; however,the values were slightly higher than the natural background tritium level. Additionally, the tritium concentration shows a seasonal variation: It was higher in autumn and winter and lower in summer and spring. A comparison of concentrations in precipitation in Shanghai and around the Qinshan Nuclear Power Plant reveals no correlation,implying that the nuclear power plant operations may not affect the environment of Shanghai. Thus, the raised tritium concentrations in Shanghai might be due to the effects of monsoons, spring leak, raindrop, or other activities that generate tritium there. Those activities may include chemistry research that uses tritium as a tracer.     

微机在核物理实验应用中的抗干扰问题

本文简单介绍了计算机在核物理技术应用中的各种噪声，并初步探讨了抑制噪声的方法。     

Tritium concentrations in precipitation in Shanghai

Beamline BL17 U1 at Shanghai Synchrotron Radiation Facility is an energy-tunable macromolecular crystallography beamline that has been in user operation since 2009. Growing demand from the user community for a small beam and related experimental methods have motivated upgrades of the devices in the endstation.Minibeam modes have already been developed for operation. A self-integrated diffractometer reduces the sphere of confusion of the rotatory axis to 1μm. The new diffractometer is equipped with an upgraded on-axis viewing system that can improve the resolving power. Additionally,the area detector was also upgraded to the newest generation of detectors, the EIGER X 16 M, which can collect data at 133 Hz. After these upgrades, the endstation became virtually new. This paper covers the upgrade of the endstation devices and gives the first data collection results.     

2010年的美国铀矿业

2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44％.铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08％.     

我国东南沿海城市地下建筑氡浓度分布

为了解东南沿海城市地下建筑氡浓度的分布，用固体核径迹法(SSNTD’s)，分别在春、夏、冬3季对沿海7城市地下建筑室内氡浓度进行调查。结果表明，福州具有最高的平均氡浓度，上海的平均氡浓度最低。季节的变化对地下建筑室内氡浓度有影响，各城市氡浓度平均值夏季最高、冬季最低。各城市夏季氡浓度与该城市的年均值的比值与城市中各测点氡浓度之间的离散度有一定的相关性。夏季地下建筑室内氡浓度高的城市，它的平均氡浓度受某些具有高氡水平测点的影响大。     

Plutonium use in nuclear power in Russia

Conclusions The following concept of plutonium utilization based on the evolutionary development of the traditional technology in our country arises: The main problem of any short-term program of dealing with plutonium must be solved — reliable and safe storage of separated energy plutonium and freed weapons plutonium before utilization in reactors. Plutonium (mainly energy plutonium) is utilized primarily in BN-800 fast reactors and the development of technology using weapons plutonium in BN-600 reactors starts. In the future attention should be focused on nuclear-power centers patterned after the Industrial Association “Mayak” (RT-1 plant, Complex 300, BN-800) with reliable nonproliferation of weapons plutonium. It is extremely important to speed up work on the completion of Complex 300: This work must be completed before BN-800 is ready. In the future efforts must be concentrated on the following: development and implementation, in BN-800, of an economically more efficient plutonium-burning core; the possibility of building light-water reactors with the required degree of safety for effective plutonium utilization must be justified (including a “cold” core based on cermet fuel); and, development and implementation of technology for a safe and an ecologically acceptable closed nuclear fuel cycle based on plutonium and²³³U with burnout of Am, Np, and Cm. Ministry of Atomic Energy of the Russian Federation. Institute of Physics and Power Engineering. A. A. Bochvar All-Union Scientific-Research Institute of Standardization in Machine Building. Special Design Office for Machines. Translated from Atomnaya énergiya, Vol. 76, No. 4, pp. 326–332, April, 1994.