机体脂质过氧化及抗脂质过氧化剂的研究

采用改良TBA法测定了不同情况下动物和人的血清与组织中LPO含量,观察了三种制剂对机体受照射所致脂质过氧化作用的影响。其内容包括:(1)大鼠及成人血清LPO正常值;(2)大鼠某些组织中LPO正常值;(3)某些精神病患者及某些恶性肿瘤患者接受放疗前后血清LPO含量的变化;(4)γ射线整体照射后大鼠某些组织中LPO含量的变化;(5)Th(NO_3)_4内照射后小鼠某些组织中LPO含量的变化;(6)知母宁、单宁酸和鲨烯等几种制剂对机体受照射所致脂质过氧化作用的影响。结果表明:(1)某些精神病患者血清LPO含量显著增高;(2)某些恶性肿瘤患者接受放疗前后其血清LPO含量差别十分显著;(3)内照射后小鼠某些组织中LPO含量显著升高,其变化与组织中蛋白含量的变化呈负相关;(4)小鼠在接受γ射线整体照射后其某些组织中LPO含量与辐射剂量在0～4Gy范围内呈现良好的线性关系;(5)知母宁、单宁酸和鲨烯等三种制剂皆有降低照射小鼠肝、脾和肾中LPO含量的作用,其中知母宁的作用明显优于单宁酸和鲨烯。     

辐射对小鼠组织中脂质过氧化物和蛋白质的影响及单宁酸与鲨烯的抗脂质过氧化作用

采用改良的TBA比色法测定组织中的脂质过氧化物(LPO)。结果表明:(1)Th(NO_3)_4内照射后第15d时,小鼠肝、脾、肾和骨髓中的LPO含量明显升高,而组织中的蛋白质却明显降低,两者呈负相关;(2)γ线整体照射(2—4Gy)后72h,小鼠肝、脾和肾中的LPO含量随着剂量的增加而升高。辐射剂量与LPO含量之间呈现显著线性关系;(3)单宁酸与鲨烯有抗脂质过氧化作用。     

二甲亚砜和维生素E对照射小鼠脂质过氧化的影响

二甲亚砜（ＤＭＳＯ）和维生素Ｅ（ＶｉｔＥ）都是自由基清除剂，可抑制或阻断由自由基引发的脂质过氧化反应，减轻组织损伤和细胞的破坏。本研究应用荧光分光光度法，通过测定小鼠血清中脂质过氧化代谢产物丙二醛（ＭＤＡ）的含量来研究不同浓度的ＤＭＳＯ和维生素Ｅ对γ射线照射后小鼠的保护作用，以及两者联合应用的效果。结果表明：ＤＭＳＯ的保护作用优于ＶｉｔＥ，最大脂质过氧化抑制率（４．０Ｇｙ）分别为５５．１％和５３．６％，两者的最佳用量分别为１０ｍｇ／ｇ体重和０．２５ｍｇ／ｇ体重，联合用药的作用效果（最大脂质过氧化抑制率为６０．１％）大于单独使用时的效果。     

α2M对辐射引起细胞自由基变化的影响

采用６０Ｃｏγ射线照射人皮肤成纤维细胞，并在照射前、后给予不同剂量的甲２巨球蛋白（α２Ｍ），用细胞色素Ｃ法、ＴＢＡ法及邻苯二酚自氧化法分别测定细胞超氧阴离子自由基（Ｏ２）释放、脂质过氧化（ＬＰＯ）水平及超氧化物歧化酶（ＳＯＤ）活力。发现细胞受照后Ｏ２释放和ＬＰＯ水平显著增高（ｐ＜０，０１）；Ｏ２释放与照射剂量呈正相关（ｒ＝０．９６６，Ｐ＜０．０１），ＳＯＤ活力显著下降（Ｐ＜０．０１），且与照射剂量呈负相关（γ＝０．９６６，Ｐ＜０．０１）。照射后给予α２Ｍ能显著抑制Ｏ２释放（Ｐ＜０．０１）、降低ＬＰＯ水平。     

缺氧和γ射线连续照射对小鼠的损伤效应

缺氧以及γ射线连续照射，或者两种因素复合作用，均能使小鼠肝、脾和心组织中ＬＰＯ含量出现不同程度增加。ＳＯＤ活力出现不同程度增高。     

二甲亚砜和维生素E对照剂小鼠脂质过氧化的影响

二甲亚砜（ＤＭＳＯ）和维生素Ｅ（Ｖｉｔ Ｅ）都是自由基清除剂，可抑制或阻断由自由基引发的脂质过氧化反应，减轻组织损伤和细胞的破坏。本研究应用荧光分光光度法，通过测定小鼠血清中脂质过氧化代谢产物丙二醛（ＭＤＡ）的含量来研究不同浓度的ＤＭＳＯ和维生素Ｅ对γ射线照射后小鼠的保护作用，以及两者联合应用的效果。结果表明：ＤＭＳＯ的保护作用优于Ｖｉｔ Ｅ，最大脂质过氧化抑制率（４．０Ｇｙ）分别为５５．１％和５     

慢性γ射线照射复合苯,甲苯和一氧化碳吸入对动物细？…

四因素两剂量按正交表Ｌ８（２＾７）设计用家兔和小鼠在密闭舱内进行８组试验。γ射线的两剂量，对家兔为０．０３７５和０．００７５Ｇｙ／ｄ，对小鼠为０．０４７３和０．００９５Ｇｙ／ｄ，苯、甲苯和与经碳两浓度分别为１８２±３３和４０±１５ｍｇ／ｍ＾３、４０７±６８和９０±３０ｍｇ／ｍ＾３、２７８±８和９３±４ｍｇ／ｍ＾３。实验每天２ｈ，每周５ｄ，持续８周，结果如下：（１）γ射线、苯和甲苯对诱发家兔淋巴细胞     

电离辐射与镉之间的交叉适应性反应

利用小鼠胚胎细胞探电离辐射与镉之间的细胞遗传学交叉适应性反应，结果表明：预先给孕９ｄ小鼠全身照射１，２，４和８ｃＧｙ＾６０Ｃｏγ射线，可降低由随后按体重４ｍｇ／ｋｇ镉引起的染色体畸变率，相反，预先给予孕鼠０，２５，０．５，１．０和２。．０ｍｇ／ｋｇ镉处理可降低随后由１．５Ｇ＾６０Ｃｏγ一全身照射引起的染色体畸变率。     

某些中药活性成分抗氧化和清除自由基作用的研究(英文)

采用改良的TBA分光光度法研究知母宁、槲皮素与单宁酸对辐射所致小鼠组织中LPO含量升高的抑制作用。用ESR方法研究了上述三种制剂对辐照所致自由基的清除作用。结果显示,知母宁、槲皮素的抗氧化作用优于单宁酸,而清除自由基作用三者相仿。     

几种制剂清除辐射所致自由基的ESR研究

本文以５’－ＴＭＰ作为ＤＮＡ的模型,ｔ－ＮＢ作为自旋捕集剂,采用ＥＳＲ方法研究了ＤＮＡ受γ射线照射产生自由基,以及知母宁,槲皮素,单宁酸,海藻硫酸多糖,云芝多糖和螺旋藻等几种制剂的辐射防护作用。结果表明,受照５’－ＴＭＰ分子的自旋捕集ＥＳＲ信号具有典型的特征性谱线,证实存在５‘－ＴＭＰ自由基,且上述几种中药制剂均有集自由基的作用,其中尤以知母宁,单宁酸和槲皮素效果为佳。     

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。     

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.     

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.     

微型X射线管空气比释动能和能谱的测量

为研究微型X射线管的特性,通过电离室测量光管出射口30 cm远处的空气比释动能,使用高纯锗探测器分别测量了Ag过滤和Cu过滤下的X射线能谱。结果表明,空气比释动能随电流的增加有线性增加的趋势,能谱图明显的观察到银的两个特征X射线。完成了微型X射线管空气比释动能和能谱的测量方法以及实验测量的工作,为微型x射线管下辐射质的建立提够了条件基础。     

Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow

The measurement of void fraction is of importance to the oil industry and chemical industry. In this article, the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy.