Objective: to evaluate the incorporation of BPA by glioma cell lines, and to observe its relationship with the temperature and the concentration of BPA. Methods: C6, U251 and rat astrocyte cells were incubated in a culture medium, in which 10B concentration was 20, 40, 60, 80, 100 μg/mL for 24 h. Boron concentration in the cells was measured induced couple plasma-atomic emission spectroscopy (ICP-AES). C6 cells were pre-incubated for 24 h with different boron concentrations in growth medium. Then the mediums were changed to boron-free ones, and boron content was assessed after 1, 2, 3 h. Results: The content of the 10B in cells was increasing with the increasing concentration of BPA, and the boron concentration ratios of glioma cells to astrocyte are 2.2. The BPA efflux is slower at the lower temperature. Conclusion: BPA has a selectivity for glioma cells, and the results of the efflux assay confirm the temperature dependence of the BPA transport out of the cells.

Objective: U251 cells were exposed to fast neutrons of 14 MeV energy, and dose-response relationships were derived; Methods:cell samples were exposed to fast neutrons. Radiation doses were 1 Gy, 3 Gy, 5 Gy and 7 Gy respectively. The cell survival, apoptotic rate and proliferation were tested after irradiation; Result: with the growth of the radiation dose, cell survival was declined, and apoptotic rate was promoted; the speed of the cell proliferation, which was observed 48 h after irradiation, was slowed down viously; Conclusion: compared to γ ray, fast neutrons have higher relative biological effectiveness.

Using neutrons of 14 MeV generated by 600 kV Cockcroft-Walton accelerator,the DNA samples with or without mannitol or VND3207 were irradiated with various absorbed doses,and the DNA strand breaks were determined by means of gel electrophoresis.The results indicate that neutron can produce the DNA single-and double-strand breaks,and the yields of strand breaks increase with the dose increment,i.e.there is a distinct dose response.Although for the solution system with additive of mannitol or VND3207,there is also a dose response,the yields of DNA strand breaks are much less than that without mannitol or VND3207 solution.It can be suggested that mannitol or VND3207 reduces the yields of DNA single-and double-strand breaks induced by neutron irradiation efficiently,and mannitol or VND3207 has stronger capability of radioprotection against neutron radiation.

The pUC19 plasmid DNA solutions in different DNA concentrations,with or without mannitol,were irradiated by 16 MeV protons to different doses.Changes in the DNA form were observed by means of gel electrophoresis in order to study effects of dose and DNA concentration on yields of DNA strand breaks.The results indicate that the dose and DNA concentration response exist in two solution systems,the forms of DNA changed from intact supercoiled to open circular,in a linear relationship with the dose.The yields of DNA strand breaks in DNA solution without mannitol are much more than that those with mannitol,illuminating that mannitol can scavenge the free radicals and reduce the yields of DNA single and double strand breaks induced by protons efficiently.In addition,the dose effects of DNA damage were investigated at a concentration of 10 or 100 ng/?L.The results show that dilute DNA solution need lower dose than the dense solution in observing similar degree of damage.

To evaluate the influence of the DNA concentra-tion in the aqueous solution on DNA radiation damage, the plasmid DNA in the presence or absence of Mannitol (scavenger of free radical OH-) was irradiated by 7Li ions and γ rays at various DNA concentrations. Gel electrophore-sis analysis revealed that the DNA damage of single and double strand breaks induced by irradiation was dependent on DNA concentra-tion and became more severe at lower DNA concentration in the radiation experiment when all others parameters are the same. In the con-dition of γ-ray irradiation, most of double strand breaks (DSB) damage was neutralized and less associated with DNA concentration in the presence of mannitol. However, under 7Li irradiation, the DSB damage could not be cleared by mannitol but was gradually aggravated with de- creasing DNA concentrations. Our study sheds light on the underlying mechanisms in the DNA radiation damage process. And there are poten-tial significances for the human space flight, cancer therapy by heavy ions as well as the ra-diation security assessment.

To measure the protective effect of salidroside on radiation,the plasmid DNA samples in TE Buffers with different concentrations of salidroside were irradiated by 14.2 MeV protons(linear energy transfer = 3.5 keV/μm) andγrays respectively.The images of gel electrophoresis and the DNA forms distribution showed that DNA lesions became lightened with increasing salidroside concentration for both kinds of radiations.At the same time,there were linear DNA forms come forth in DNA samples after irradiated by protons at lower concentrations of salidroside,and that did not appear after irradiated by 7 rays.It should be correlative with the direct ionizing of protons.

近年来，随着核科学技术的不断发展，核技术的广泛应用，核辐射损伤得到了人们的普遍关注。重离子束治癌的发展以及载人太空探索的需要，使得重离子对人体组织的损伤效应成为人们的关注热点。与此同时，各种低毒高效的辐射药物的开发也引起了人们的极大兴趣。

<正>红景天为景天科景天属(RhodiolaL.)多年生草本植物,具有极强的环境适应能力和生命力。近年来,研究证明红景天苷具有抗疲劳、抗衰老、免疫调节、清除自由基、增强记忆、改善睡眠等多种药理作用。研究红景天对辐射损伤的保护作用对开发和筛选低毒和高效的抗辐射药物具有重要的意义。但是,以往的实验主要集中在低LET辐射,本实验室在进行低LET辐射研究的同时还进行了质子的辐照实验。

<正>在长期载人航天中,除失重外,空间辐射对人是一个严重的威胁,其中空间辐射危害,需考虑的关键粒子是质子和重离子。深入了解空间辐射环境特点及危害程度,对保

<正>15MeV质子致DNA损伤实验在HI-13串列加速器的Q3D磁谱仪终端上开展,实验内容包括两个方面,一是质子辐照方案的改进,二是质子致DNA损伤实验。质子辐照方案的改进,是因为质子质量较轻,穿透力极强,在由加速器引出直至样品照射端的过程中,极有可能与其他介质发生作用,从而产生一定数量的次级粒子、中子和γ射线,如何采取有效的措施屏蔽这些因素的影响,是质子致生物损伤研究中必须解决的关键问题之一。因此,我们

<正>DNA作为生物体中的一类基本生物大分子,是离子辐射引致生物效应的关键靶分子,也一直是辐射生物学研究的焦点之一。DNA损伤随着辐照剂量的变化是研究的基础,本实验室对溶于水溶液的DNA受各种辐照后的损伤已经进行了详细的研究。但是仍然缺少溶于TE缓冲液的DNA受到辐照损伤后的数据,TE缓冲液是接近细胞环境的一种溶液,了解DNA在TE中受辐照后损伤的情况有利于解释细胞辐照损伤的机制。

<正>在空间辐射环境中,辐射源主要是银河宇宙射线(GCR)和随机发生的太阳粒子辐射(质子事件)。其中以质子含量最为丰富,其次为α粒子和少量其它更重的离子。已有的模型计算结果表明,

To evaluate the influence of the DNA concentration in the aqueous solution on DNA radiation damage, the plasmid DNA in the presence or absence of Mannitol (scavenger of free radical OH•) was irradiated by 7Li ions and γ rays at various DNA concentrations. Gel electrophoresis analysis revealed that the DNA damage of single and double strand breaks induced by irradiation became more severe at lower DNA concentration. In the condition of γ-ray irradiation, most of double strand breaks (DSB) damage was neutralized and less associated with DNA concentration in the presence of mannitol. However, under 7Li irradiation, DSB damage could not be cleared by mannitol but was gradually aggravated with decreasing DNA concentrations. These findings imply that under low-LET irradiation, most of the DSB damage is generated by free radical OH• diffusion, and thus may be counteracted by scavengers, while at higher-LET irradiation, quite a fraction of DSB induction is caused by direct ionizing energy deposition of heavy ions, which cannot be eliminated. This work also indicates that the proportion between free radical damage and direct ionizing damage is a constant which is independent of DNA concentration when the DNA concentration is under a certain value (50 ng/μL). Our study sheds light on the underlying mechanisms in the DNA radiation damage process.

<正>电离辐射致DNA损伤的程度受到很多因素的影响,如剂量、剂量率、射线种类、DNA浓度等。北京师范大学周宏余课题组利用电子顺磁共振谱仪测量了不同电荷态的低能C离子辐照丙氨酸薄

A radioactive multitracer solution of the 24 elements, e.g. Be, Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Zn, Y, Zr, Mo, Nb, Tc, Ru, Ag and In, was obtained from the nuclear reaction of 25 MeV/u 40Ar+Se with a series of chemical process. The multitracer solution was orally administered to normal and muscular tumour-bearing mice of male Balb/c mice. Urine and faeces samples of mice were collected. The two group mice were sacrificed after 96 h. The uptake of 17 elements, Na, Rb, Ga, As, Sc, V, Cr, Mn, Co, Fe, Zn, Y, Zr, Tc, Ru, Ag and In, were simultaneously detected in normal mice while 15 elements, Na, Rb, Ga, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Tc, Ru, Ag and In, were simultaneously detected in tumour-bearing mice. Our results indicate that the majority of the detected elements were distributed in liver, kidney, pelt, tumour while a small fraction of the biotrace elements were distributed in heart and spleen (tumour-bearing mice) in the two groups of mice. The higher concentrations of Fe, Na, Mn were detected in heart or kidney of normal mice. Na, Mn, Fe and Co showed better absorption in most tissues in the normal mice, except for Na and Mn in heart.

A male sterile mutant named 39I_3-2 was selected from the M_3 generation of Nongda 108(a maize variety) which dry seeds were irradiated with 30Gy 7Li,and combinations between male sterile plants and other fertile plants were also obtained through bagging cross.The characteristics of the male sterile mutant and its fertilities of combinations were studied,and the fertilities of the F_2 generation were surveyed.The results showed that the sterile material was thoroughly abortive,and the sterile trail was stable,which indicated a genetic feature of single recessive gene controlled nucleus sterility.The appearance of male sterile mutant was caused through gene mutation by heavy ion irradiation.

To measure the DNA lesions and the form of transformation in plasmid DNA irradiated with protons,the plasmid DNA samples were irradiated with 16.4 MeV proton(linear energy transfer=3.12 keV/μm) in aqueous solution containing 0 mmol/L or 600 mmol/L mannitol.DNA were measured by gel electrophoresis and Alpha Innotech digital imaging system.For proton without mannitol,DNA lesions were very evident at the dose of 50 Gy.The fractions of SC form and OC form decreased till they disappeared with increasing doses.The short fragments of DNA came forth at the dose of 300 Gy.In the presence of 600 mmol/L mannitol,DNA lesions were restrained.However the fraction of OC form increased obviously with increasing doses,which showed that there are some direct damages with the proton irradiation.These provide important experimental data for the dangerous assessment of space radiation and proton therapy.

Excitation functions have been measured for different projectile-like fragments produced in Al-27(F-19,x)y reactions at incident energies from 110.25 to 118.75 MeV in 250 keV steps. Strong cross section fluctuations of the excitation functions are observed. The cross- correlation coefficients of the excitation functions for different atomic number Z and for different scattering angle theta(cm) have been deduced. These coefficients are much larger than the statistical theoretical calculated ones. This indicates that there are strong correlations between different exit channels in the dissipative heavy ion Collision of Al-27(F-19,x)y.