氚水的致癌效应研究(英文)

氚水的致癌效应研究工作包括两部分。第一部分为体外细胞转化实验,使CHL-1细胞受氚水照射24～96h,比活度为9.25×10~5～3.5×10~6Bq/ml,累积剂量为0.055～0.88Gy。并以~(137)Csγ射线为参考射线,以恶性转化率为终点求得氚水相对于γ射线的RBE值为1.6。第二部分观察了大鼠长期(1.5a)饮用氚水,其比活度为2.22×10~5,1.11×10~5Bq/ml,对照组饮用自来水。结果表明,大剂量组的肿瘤总发病率和恶性肿瘤的发病率与小剂量组和对照组相比在统计学上有明显差异。     

氚水的致癌效应研究

氚水的致癌效应研究工作包括两部分。第一部分为体外细胞转化实验,使CHL-1细胞受氚水照射24～96h,比活度为9.25×10~5～3.5×10~6Bg/ml,累积剂量为0.055～0.88Gy。并以~(137)Cs γ射线为参考射线,以恶性转化率为终点求得氚水相对于γ射线的RBE值为1.6。第二部分观察了大鼠长期(1.5a)饮用氚水、其比活度为2.22×10~5,1.11×10~5Bq/ml,对照组饮用自来水。结果表明,大剂量组的肿瘤总发病率和恶性肿瘤的发病率与小剂量组和对照组相比在统计学上有明显差异。     

出生前氚水照射引起大鼠脑损伤的超微结构研究

给妊娠11 d 的大鼠经腹腔单次注入氚水,使体水氚浓度分别为5.55×10~6Bq/mL和5.55×10~5Bq/mL 体水,其1 d 龄和18 d 龄仔鼠累积吸收剂量分别为1.6—1.7Gy和0.16—0.17Gy,可引起其大脑和小脑皮质神经元细胞核及核周质中细胞器等超微结构明显损伤。90 d 龄时上述超微结构改变已消失,但仍可见增生的胶质细胞突起填于受损的神经毡结构中。     

饮用水中的放射性核素所造成的危险

本文对饮用水中放射性核素所造成的危险进行了评价。来自放射性核素的主要危险是自然产出的Ra、U和Rn。这些元素产出的平均水平为:~(226)Ra为1.11×10~(-2)—2.96×10~(-2)Bq/L,~(228)Ra为1.48×10~(-2)—3.7×10~(-2)Bq/L,天然铀为1.11×~(-2)—7.4×10~(-2)Bq/L,~(222)Rn为1.85—12.95Bq/L,~(210)pb为<0.41×10~(-2)Bq/L,     

出生前氚水照射致大鼠脑细胞缺失的剂量效应关系研究

将妊娠11天的大鼠经腹腔单次注入3.70×100~4—5.55×10~6Bq/mL(体水)氚水,仔鼠出生18天后开颅取出仔鼠大脑组织,制成脑组织切片,观察大脑皮质第Ⅴ层锥体细胞数的变化。结果表明,仔鼠大脑锥体细胞数随剂量的增加而显著减少(p<0.01);在仔鼠总吸收剂量为0.012—1.7Gy范围内,大脑锥体细胞缺失率Y(％)与剂量D(Gy)可拟合成对数直线回归方程Y=27.1+8.311gD。     

氚化合物对人血淋巴细胞SCE的影响

本文用不同活度的~3H-TdR及~3H-UdR加入人血淋巴细胞连续培养,以了解氚对细胞分裂周期及SCE频度的影响。两种氚化合物均可使SCE频度增加,并可使细胞分裂周期延缓。SCE频度随氚活度的增加而明显增加。在导致分裂周期延缓程度上~3H-TdR<~3H-UdR。~3H-UdR各组的SCE频度均值均高于相同浓度的~3H-TdR组,除3.7×10~3Bq/mL组外,其他各组与~3H-TdR对应组之间的差异非常显著(t检验,p<0.01)。氚化合物对细胞增殖速度有影响,细胞增殖速度指数(PRI)与SCE频度有关,SCE频度越高,PRI值就越低。     

武汉市水体中天然放射性水平调查

本文介绍了武汉市江河、湖泊和饮用水中 U、Th、~(226)Ra、~(40)K 水平的调查结果,其范围值分别为:U,(7.01—10.08)×10~(-3)Bq/L;Th,(3.61—13.92)×10~(-4)Bq/L,~(226)Ra,(2.90—4.38)×10~(-3)Bq/L;~(40)K,(5.86—28.68)×10~(-2)Bq/L。枯水期江河水中天然放射性核素含量明显高于平水期,同一水期中放射性核素分布比较均匀,均在正常本底范围内。     

土壤中钚含量测定结果的比对

本文叙述了有7个实验室参加的土壤中钚含量测定结果的比对。比对结果表明,样品前处理采用酸浸取法或全溶法测出的结果差异不显著;在置信度为95%时,样品中钚含量平均值的置信区间对酸浸取法和全溶法分别为(1.49—2.23)×10~(-3)Bq/g和(1.18—2.22)×10~(-3)Bq/g。     

强流中子发生器运行期间氚污染调查

本文报道了14MeV 强流(3.3×10~(12)n/s)中子发生器运行期间空气中氚浓度的调查结果。各采样点空气中的氚浓度分别为:手套箱,8.9MBq/m~3;发生器大厅走道,6.6kBq/m~3;氘操作室,4.1kBq/m~3;尾气排放口,9.7×10~7Bq/m~3;发生器大厅外,98Bq/m~3。调查结果表明,发生器运行期间工作场所和居民区空气中的氚浓度有所增加,但均未超过国家防护标准中对工作人员和对公众的导出空气浓度(DAC)。     

氚水引起大鼠肝细胞损伤的电镜观察

本文报道了经腹腔注入7.4×10~6Bq/g体重的氚水后不同时间大鼠肝组织超微结构的变化,同时估算了大鼠体内氚水累积吸收剂量。结果表明:注后1天,肝细胞出现变化,注后7天,损伤明显,注后35天细胞形态结构基本恢复正常。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

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.     

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。     

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.     

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.     

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.     

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.     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.     

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.