氮离子束注入对玉米体细胞培养影响的初步研究

将能量为６０ｋｅＶ、剂量为２×１０＾１６Ｎ＾＋／ｃｍ＾２的氮离子束分别注入３个玉米自交系的成熟种子。从其Ｍ１成株上取下未成熟的胚作外植体，在ＭＮ和ＡＧ培养基上进行离体培养，以末注入的相同材料为对照。结果发现，Ｍ１的平均愈伤组织诱导频率比对照高１１．７％，其中在ＭＮ和ＡＧ培养基上，分别比对照高１５．５％和７．９％。不同类型的材料，在两种培养基上的愈伤组织诱导频率存在差异，而且在诱导过程中Ｍ１与对照材     

重离子束辐照对苜蓿外植体离体培养的影响及下胚轴再生体的RAPD分析

采用初始能量为100 MeV/u的重离子束12C6 对紫花苜蓿下胚轴及子叶外植体进行辐照处理,研究重离子辐照对愈伤组织诱导状态及诱导率、愈伤组织相对生长率、体细胞胚诱导率及植株再生的影响.结果表明,重离子辐照对下胚轴及子叶愈伤组织的诱导具有抑制作用,且出愈率随着辐照剂量的增大而降低;在继代培养过程中,其愈伤组织相对生长率均高于对照组,外植体本身对重离子辐照所造成的损伤具有恢复能力;辐照处理对体细胞胚胎诱导也有影响,30Gy时,下胚轴诱导的体细胞胚胎发生较对照组早,数量多,较早地得到再生植株;而50 Gy时,所得到的体细胞胚未能发育成再生植株.同时应用随机扩增多态性DNA (Random amplified polymorphic DNA,RAPD)技术对重离子辐照处理下胚轴所得再生植株进行检测分析,结果表明:所采用的20条随机引物中有11条在对照及处理组所得再生植株之间扩增出差异性多态条带,表明了重离子辐照引起苜蓿再生植株基因组DNA发生变异.     

诱变处理对水稻离体培养的生物学效应

以水稻成熟种胚为外植体,研究了不同类型水稻体细胞组织培养的辐射生物学效应,γ射线与NaN_3复合处理的体细胞培养反应,以及水稻花药愈伤组织的γ辐射效应。结果表明,各品种的出愈率、愈伤组织生长率的辐射剂量效应曲线可以用多靶单击模型拟合。不同类型品种的体细胞培养辐射效应存在着明显的差异。小剂量(100Gy,150Gy)时,有促进绿苗分化的作用。经γ射线加NaN_3复合处理,明显降低种子出愈率、初代培养愈伤组织生长率和分化率,其处理效应高于单独处理。但第2、3次培养时,γ射线处理效应大于γ射线加NaN_3复合处理效应。在以水稻成熟种胚作外植体时,培养前采用200Gy~(137)Csγ射线加2mmolNaN_3进行复合处理是可行的。水稻花药愈伤组织经30Gyγ射线处理可提高连续培养的绿苗分化率。     

诱变处理对水稻离体培养的生物学效应

以水稻成熟种胚为外植体,研究了不同类型水稻体细胞组织培养的辐射生物学效应,γ射线与NaN_3复合处理的体细胞培养反应,以及水稻花药愈伤组织的γ辐射效应。结果表明,各品种的出愈率、愈伤组织生长率的辐射剂量效应曲线可以用多靶单击模型拟合。不同类型品种的体细胞培养辐射效应存在着明显的差异。小剂量(100 Gy,150 Gy)时,有促进绿苗分化的作用。经γ射线加NaN_3复合处理,明显降低种子出愈率、初代培养愈伤组织生长率和分化率,其处理效应高于单独处理。但第2、3次培养时,γ射线处理效应大于γ射线加NaN_3复合处理效应。在以水稻成熟种胚作外植体时,培养前采用200 Gy ~(137)Cs γ射线加2mmol NaN_3进行复合处理是可行的。水稻花药愈伤组织经30Gy γ射线处理可提高连续培养的绿苗分化率。     

离子注入甜菜杂交种当代生物效应

以甜菜杂交种为处理材料 ,用N+作为诱变源 ,以 35keV的能量 ,分别以 4 0次、6 0次脉冲 ,注入剂量分别为 4× 10 16 N+/cm2 和 6× 10 16 N+/cm2 进行激发诱变。结果显示 ,甜菜杂交种的产量、含糖率均有明显的提高。     

氧化钚污染手掌的临床处理

一例患者被氧化钚污染的铁丝刺伤,经初步去污后测知钚污染量为1.147×10~5Bq。在当地医院切除钚污染组织并进行了DTPA促排治疗。术后伤面残留钚量为7.03×10~3Bq。在初次手术后的第42天又对残留有钚的污染组织作广泛切除和肘滑车上淋巴结摘除术,伤面缺损以足嗻全厚皮片覆盖。术中及术后仍以DTPA促排治疗。在术后5个月、两年及三年时复查,并以DTPA局部及肌肉注射,伤面钚残留量由术后的111Bq逐渐降至83Bq、18.5Bq,最后降至仪器的本底水平。钚经伤口吸收的入血量为1.1×10~4Bq,事故后1000天经尿粪排出钚1.0×10~4Bq,占吸收入血量的90％,1000天时体内钚残存量0.1×10~4Bq待积有效剂量当量为1.3Sv。     

γ射线、秋水仙碱在水稻花药组培中对愈伤组织形成和绿苗再生的刺激效应

在水稻花药的组织培养中,对不同类型和品种,其愈伤组织的形成、绿苗的分化和再生能力有很大差异。用γ射线和秋水仙碱处理经30d左右诱导培养的水稻花药,可以有效地促进愈伤组织的形成及绿苗的分化和再生。其中,γ射线10Gy剂量处理对愈伤组织形成效果最好,20Gy剂量处理对绿苗的分化和再生效果最佳,在分化培养基中加入30mg/L秋水仙碱可明显促进绿苗的分化和再生。γ射线和秋水仙碱复合处理比各自单独处理效果更好。     

小铅玻璃防护屏的设计和制作

放射性同位素的开瓶分装,是同位素室工作中的一项重要操作。防护不好,工作人员接受辐射剂量很大。目前,不少单位用铅玻璃作防护屏,有相当好的防护效果。据了解,使用的铅玻璃中,大的规格为:700×500×50毫米,一般规格为:400×300×50毫米。每公斤价格100元。第一种规格每块8750元,第二种规格每块2860元。这样,同位素室筹建中铅玻璃的购置是一笔较大的费用。     

N+离子束和60Coγ射线辐照引起脂质过氧化产物及调节酶活性变化的比较研究

以烟草愈伤组织中超氧化自由基（O2）、过氧化氢（H2O2）和丙二醛（MDA）及超氧岐化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的产率和含量及活性为生物效应指标,比较研究了N＋离子束和60Coγ射线的辐照效应。结果表明：N＋离子束（E＝20keVD＝（1－6）×1015N＋／cm2）和γ射线（D＝135－315Gy）辐照烟草愈伤组织能够引起O2产率、H2O2和MDA含量的升高,并且升高的趋势随辐照剂量的增多而增加;同时也能够引起SOD、POD和CAT活性的变化,在N＋离子束D＝（1－3）×1015N＋／cm2和γ射线D＝135－180Gy辐照时,SOD、POD和CAT的活性增强,并且随辐照剂量的增多而增强。在N＋离子束D＝（3－6）×1015N＋／cm2,γ射线D＝180－315Gy辐照时,SOD、POD和CAT酶活性下降,其活性下降趋势随辐照剂量的增大而增强。讨论了N＋离子束辐照作用的特点。     

离子注入在番茄育种中的诱变功效

对番茄N+ 注入诱变效应进行了研究。结果表明,N+ 离子注入对番茄单果重、座果数等性状变幅大且变异率高;而对发芽率和果实的品质性状影响较小。以4×1016 / cm2 和6×1016 / cm2剂量处理,产量提高明显。不同品系、不同性状的最佳诱变剂量略有不同。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.