辐照诱导人正常肝细胞系HL-7702 细胞远后的微卫星不稳定性

采用高传能线密度(LET) 的12C6+离子束和低LET 的X 射线辐照人正常肝细胞系HL-7702 细胞,利用微卫星不稳定性(MSI) 检测来分析直接受照射细胞和通过转移培养基方式旁细胞传代八代子细胞以MSI 表征的远后效应。实验结果表明,12C6+离子束诱导的远后效应较X射线的低;旁细胞的远后效应较直接受照射细胞的高;辐射引起的MSI 与杂合性丢失(LOH) 的发生率具有位点特异性。结果提示,重离子放射治疗较X 射线放射治疗对正常组织引发的辐射风险要小,可通过对MSI 高发位点的筛选来评估放疗后患者长期生存状况和二次癌症发生风险。Human normal liver cell line HL-7702 cells were irradiated with high linear energy transfer (LET) 12C6+ ions and low-LET X-rays, respectively. Delayed effect in terms of microsatellite instability (MSI) in progenies of the directly irradiated cells and bystander cells, obtained in the way of medium transfer at the 8th passage postirradiation,were examined. The delayed effect induced by the high-LET 12C6+ ions was different from that induced by the low-LET X-rays, and a higher incidence of MSI was observed in the progenies of the cells after exposure to the X-rays than to the 12C6+ ions. We also found that the delayed effect in the progenies of the bystander cells was much more severe than thoseof directly irradiated cells. Furthermore, the events of MSI and loss of heterozygosity (LOH) induced by the ionizing radiations were not randomly distributed throughout the genome and specific loci existed indeed. These results imply that the radiation risk to normal tissues is lower in heavy ion therapy than in conventional X-ray radiotherapy, and the analysis of microsatellite loci with MSI high frequency occurrence can be applied to access long-term survival condition and second cancer risk for the patients after radiotherapy.     

羧甲基-β-1,3-葡聚糖对人肝癌HepG2细胞的放射增敏作用

本研究旨在探讨羧甲基-β-1,3葡聚糖（CMG）对人肝癌HepG2细胞X射线或12C6+离子束辐射敏感性的影响。首先用CCK-8法检测CMG对HepG2细胞的生长抑制情况,得到半数抑制浓度（IC50）为120.6μg/mL。用浓度为0.1×IC50的CMG预处理HepG2细胞24 h,再给予2 Gy X射线或12C6+离子束辐照（CMG+辐照组）;CMG未处理组直接接受2 Gy X射线或12C6+离子束辐照（辐照组）。对比分析辐照组和CMG+辐照组细胞的克隆存活、DNA损伤、凋亡与周期分布、细胞内活性氧（ROS）水平。发现:与X射线辐照组相比,相同剂量的12C6+离子辐照组克隆存活率更小,DNA损伤和周期阻滞更加严重,细胞凋亡率和细胞内ROS水平也更高。与单独X射线或12C6+离子束辐照组相比,CMG+辐照组克隆存活率明显降低,细胞凋亡率随辐照后CMG作用时间的延长而明显增加,CMG使辐照后细胞内ROS维持在一个较高的水平,同时CMG明显加重了单独辐照诱导的DNA损伤和周期阻滞。结果表明,与X射线相比,HepG2细胞对相同剂量的12C6+离子辐射更敏感;CMG可增加HepG2细胞对X射线或12C6+离子辐射的敏感性;CMG可能通过增加受照HepG2细胞内的ROS水平,加剧辐照诱导的DNA损伤,促进辐射诱导细胞凋亡而起到辐射增敏作用。This study aims to investigate the effect of carboxymethy-β-1, 3-glucan (CMG) on the sensitivity of human hepatoma HepG2 cells to X-rays or 12C6+ ions irradiation. First, the inhibitory effect of CMG on the growth of HepG2 cells was detected by CCK-8 assay, and the half maximal inhibitory concentration (IC50) was 120.6 μg/mL. HepG2 cells were pretreated with CMG at a concentration of 0.1×IC50 for 24 h and then irradiated with 2 Gy X-ray or 12C6+ ion beams (CMG + irradiation group). CMG untreated group was directly irradiated by 2 Gy X-rays or 12C6+ ions beam (irradiation group). The clone survival, DNA damage, cell apoptosis, cell cycle distribution, and intracellular reactive oxygen species (ROS) levels in irradiation group and CMG + irradiation group were comparatively analyzed. The results showed that the clone survival rate was lower, DNA damage and cycle arrest were more serious, and the rate of apoptosis and intracellular ROS levels were higher in 12C6+ ions irradiation group than those in the same dose of X-rays irradiation group. Compared with X-rays or 12C6+ ions irradiation group, the clone survival rate of CMG + irradiation group was significantly decreased, and the apoptosis rate significantly increased with the prolongation of CMG treatment post-irradiation; CMG maintained intracellular ROS at a higher level after irradiation, CMG also significantly aggravated radiation-induced DNA damage and cycle arrest. These results indicated that HepG2 cells were more sensitive to 12C6+ ions radiation than those at the same dose of X-rays. CMG increased the sensitivity of HepG2 cells to X-rays or 12C6+ ions irradiation by increasing intracellular ROS level, exacerbating radiation-induced DNA damage and promoting radiation-induced apoptosis in irradiated HepG2 cells.     

重离子对人胃癌细胞DNA错配修复基因MSH2 表达的影响

采用高传能线密度(LET) 重离子辐照人胃癌SGC7901 细胞,应用流式细胞技术、蛋白质印迹法(Western blot) 及反转录聚合酶链式反应(RT-PCR) 观察重离子诱导人胃癌SGC7901 细胞周期、凋亡和MSH2 表达状况。结果表明: 与对照组相比,SGC7901 细胞在辐射后72 h G2/M 期所占细胞比率(33.26±0.08) 和凋亡率(24.16±0.64) 均达到峰值,且呈时间依赖性增加;经重离子照射后,DNA错配修复基因MSH2 mRNA 和蛋白表达水平在6 h 最高。结果提示:重离子在体外诱导SGC7901 细胞周期阻滞和凋亡,且具有显著的时间依赖性效应;重离子在一定剂量和时间下,诱导了SGC7901 细胞MSH2 基因表达。DNA错配修复基因MSH2 可能参与了重离子辐照诱导胃癌细胞DNA损伤的修复应答。Human gastric cancer cell SGC7901 were irradiated with high linear energy transfer (LET) carbon ion. Apoptotic cells after irradiation were analyzed by flow cytometry and expression of MSH2 genes in the irradiated cells was detected by western blot and RT-PCR assay. Compared with the control group, we found that the number of G2/M (33.26±0.08) or apoptosis (24.16±0.64) of SGC7901 cells reached a maximum after irradiation at 72 h in a dose dependent manner. And heavy ion irradiation efficiently up-regulated the expression of MSH2 gene at 4.0 Gy after being irradiated 6 h. These results imply that heavy ion beam could induce cell apoptosis and cell cycle arrest in time-dependent manners. Furthermore, expression of MSH2 genes activated by carbon ion irradiation suggests that DNA mismatch repair gene MSH2 might be involved in DNA repair pathways.     

二烯丙基二硫对12C6+离子束辐照损伤小鼠的保护作用研究

研究大蒜素重要活性成分二烯丙基二硫( Diallyl disulfide, 简称DADS) 对12C6+离子束辐照损伤小鼠的保护作用。利用4 Gy 剂量12C6+离子束对不同浓度DADS 预处理的雄性昆明小鼠进行单次全身照射。随后检测骨髓细胞微核率和肝组织中丙二醛(MDA) 含量、蛋白质总羰基含量、总抗氧化能力( TAOC)及谷丙转氨酶(ALT ) 活性。结果显示,与单纯照射组相比,低浓度DADS 预处理组骨髓细胞微核率和肝组织ALT 活性均显著降低(p<0.001),而肝组织T-AOC明显增强( p < 0.05 );中浓度DADS 预处理组肝组织中MDA 含量和蛋白质总羰基含量均显著减少( p < 0.05 )。结果提示,DADS通过抑制氧化应激,有效地保护了脂质、蛋白质和遗传物质免受12C6+离子束辐照引起的损伤。The radioprotective effect of Diallyl disulfide (DADS) on 12C6+ ion irradiation was studied. Pretreated with DADS of different concentration, male Kung-Ming mice were exposed to whole body irradiation with dosage of 4 Gy 12C6+ ion. The animals were sacrificed after irradiation. Then the bone marrow cells micronucleus rate, malondialdehyde (MDA) levels, content of protein carbonylation, total antioxidant capacity ( T-AOC) and alanine aminotransferase ( ALT ) activity were measured. As compared with those in irradiated group, the ratio of micronucleus cells in marrow and the hepatic ALT activity in the pretreatment group with low dose DADS decreased significantly ( p < 0.001 ). Similarly,the content of protein carbonylation and the levels of MDA droped dramatically in the group with middle dose DADS treatment ( p < 0.05 ). On the contrary, the hepatic T-AOC increased markedly in the group of pretreatment with low dose DADS ( p < 0.05 ). The results showed that DADS protect lipoid, protein and genetic material from 12C6+ ion irradiation by right of resisting oxidative stress.     

12C6+束辐照引起的实验猪皮肤急性损伤反应的研究

探讨了正常皮肤对重离子辐照急性损伤反应的耐受性, 为重离子治癌临床应用提供安全性检测的实验依据。实验前10 min, 实验猪肌肉注射复方氯胺酮1.2 mg/kg进行麻醉, 然后在兰州重离子研究装置（HIRFL）辐照终端利用12C6+束照射, 辐照剂量分别为0, 12, 21和27 Gy, 辐照分3次完成, 剂量率约为1.2 Gy/min, Bragg峰区照射, 辐照后每隔7 d对照射野拍照并活检取样, 做HE组织病理学观察。不同剂量12C6+离子束辐照实验猪皮肤后, 皮肤外观反应随辐照剂量增大而加快, 表现为肿胀和色素沉积等; 皮肤组织结构的变化明显, 上皮细胞排列紊乱、 萎缩、 空泡变性; 基本恢复正常所需时间也越长, 且都存在明显的剂量效应关系。结果表明, 辐照剂量范围为0—27 Gy时, 重离子对正常皮肤的辐照是安全的。The tolerance of the normal skin to the acute radiation injury reaction induced by heavy ion beams has been studied experimentally. The experimental pigs were injected with 1.2 mg/kg ketamine in 10 min before irradiation and were irradiated with 0, 12 , 21 and 27 Gy 12C6+ ion at a dose rate of 1.2 Gy/min at the Heavy Ion Research Facility in Lanzhou（HIRFL）. The total radiation dose was finished by 3 times at Bragg Peak Region of Heavy Ion Beams.The radiation fields of skin were taken photo and performed biopsy. The contaneous tissues of radiation fields were stained by HE and examined histopatholo gical changes every seven days after irradiation. The results indicated that the cutaneous appearance reaction became more faster with radiation dosage rising and presented with swollen, melanin forming and so on after irradiated by the carbon ions at different dosage. The Pathological examination showed noticeable changes in histological and structural of experimental pigs skin, such as atrophy, vacuolation, denaturation and arranged irregularly in epithelial cells. Furthermore, the time for return to normality became longer with the increasing of radiation dosage. All indexes demonstrated correlation between the does and effects. It is concluded that the irradiation of heavy ion beams to normal skin is security when the radiation dose range is about 0—27 Gy.     

碳离子辐照对人肺癌细胞A549细胞周期进程的影响

选取对数生长期人肺癌细胞A549接受0—6.0 Gy 碳离子照射， 用克隆形成法检测细胞的存活率； 并于照射后12和24 h收集细胞， 用流式细胞术检测细胞周期各时相的细胞百分比， 观察不同剂量碳离子辐照对A549细胞周期进程的影响。 结果显示: 0—6.0 Gy 碳离子照射后细胞存活率显著下降； 照射后12 h细胞发生G0/G1期阻滞， 而照射后24 h， 1.0 Gy 照射组细胞在G0/G1期阻滞， 2.0—6.0 Gy 照射组细胞在G2/M期阻滞。 上述结果表明， 在A549细胞接受碳离子照射后的12 和24 h内， 1.0 Gy 照射可持续激活细胞G1期检查点， 而2.0—6.0 Gy 碳离子照射后其细胞周期进程是随时间变化的。 To investigate the effects of cell cycle progression of A549 cell induced by 12C6+ ion irradiation at different doses, the survival fractions of the A549 cells were determined by colony forming assay; cell cycles were analyzed by FACS at 12 h or 24 h after irradiation. The results showed that the percentage of survival in the A549 cells decreased with irradiation doses. Compared with control group， the percentage of the cells in G0/G1 phase significantly increased at 12 h after irradiation with different doses of 12C6+ ions. However， at 24 h after irradiation the percentage of the cells in G0/G1 phase significantly increased with 1.0 Gy 12C6+ ions， while the cells showed increasing percentage in G2/M phase with 2.0, 4.0 or 6.0 Gy 12C6+ ions. The results suggested that G1 cell cycle checkpoint was activated in 12—24 h after irradiation with 1.0 Gy 12C6+ ions， but after irradiation with 2.0—6.0 Gy 12C6+ ions， the cell cycle progression of the A549 cells changed with time.     

P53及其相关蛋白对X射线照射肝癌细胞周期的调节

X射线照射人肝癌细胞HepG2， 照射后细胞存活随照射剂量增大明显下降。 流式细胞术分析， 不同剂量组照射后24 h均发生G2期阻滞。 照射后不同时间组的细胞周期分布也有不同， 照射后12 h， 有显著的S期延迟。 Western Blot 显示照射后24 h P53， MDM2， P21蛋白表达上升， 并有时间效应: P53在照射后24 h之内始终维持较高表达, MDM2和P21分别在照射后6和12 h的表达最高。 X射线照射通过影响P53及其相关蛋白的表达影响细胞周期。 HepG2 cells were irradiated with X ray at the doses of 0, 1.0, 2.0, 4.0 or 8.0 Gy and separately maintained in DMEM at 37 ℃ for 0, 6, 12 or 24 h. Colony forming assay showed that cell survival decreased with the irradiation dose increasing. Cell cycle was detected by FACS, the arrest of S phase was found after 12 h irradiation and arrest of G2 phase took place at 24 h after all irradiation doses, which suggested that cell cycle distribution was different in groups gathered after different maintaining time. The results of Western blotting showed that the expression of P53, MDM2 and P21 increased more after irradiation than the control. The expression of P53 remained high at 24 h after irradiation, while the levels of MDM2 or P21 arrived at the highest at 6 h or 12 h after irradiation respectively. The expressions of P21 after irradiation were in corresponding with the cell cycle distribution in the groups of different maintaining time. In conclusion, irradiation change the distribution of cell cycle by effecting the expression of P53 and its related proteins.     

12C6+ 离子束辐照对大鼠离体主动脉环内皮依赖性舒张功能的影响

利用兰州重离子研究装置(HIRFL) 提供的高能12C6+离子束(能量为300 MeV/u,剂量率为0.5 Gy/min) 辐照大鼠离体胸主动脉环,考察了12C6+离子束辐照对主动脉环内皮依赖性舒张功能的影响,并采用NBT 还原法测定血管环生成超氧阴离子(O2􀀀) 水平,加入外源性超氧化物歧化酶(SOD) 干预探讨了O2􀀀在内皮功能损伤中的作用。研究结果表明,2.0,4.0 和6.0 Gy 的12C6+离子束辐照大鼠胸主动脉环后,可致血管内皮依赖性舒张功能的剂量依赖性明显受损(P <0.01 vs control group),并可致血管环NBT 还原能力剂量依赖性增加(4.0 Gy 时,P <0.05;6.0 Gy 时,P <0.01 vs control group)。辐照前加入外源性SOD 对6.0 Gy 12C6+离子束辐照所致血管环NBT 还原能力升高有明显抑制作用(P <0.01),对血管环内皮依赖性舒张功能也有明显的保护作用(P<0.01),但辐照后10 min 加入外源性SOD,其保护作用明显不及前者。结论显示,12C6+ 离子束辐照大鼠胸主动脉环可致血管内皮功能受损,O2 清除剂SOD 对内皮功能受损有保护作用,说明O2􀀀介导了辐照所致内皮功能损伤。Heavy ion beam has many characteristics,and it is expected to be the most suitable radiation therapy technique for malignant tumor. It is lack of depth-understanding on the potential adverse reactions caused by using this technique, because heavy ion radiotherapy is applied to clinical for a short time. Studies have shown that the vascular injury plays a pivotal role in normal tissue damage induced in the conventional radiation therapy, but there was no research report on heavy ion beam irradiation-induced vascular injury. In the present study, the isolated aortic rings of rats were irradiated by 12C6+ ion beam (300 MeV/u, 0.5 Gy/min) delivered by HIRFL(Heavy Ion Research Facility in Lanzhou), the effects of 12C6+ ion beam irradiation on aortic rings with endothelium dependent diastolic function have been investigated.NBT reduction method was used for assaying the vascular ring formation of superoxide anion (O2􀀀) level, and the involvement of superoxide anion in endothelial function injury in rats was investigated through the intervention test of exogenous superoxide dismutase (SOD) on O2. The results showed that, the vascular endothelial dependent vasodilation was impaired significantly (P < 0:01 vs control group) by irradiation with 2.0, 4.0 and 6.0 Gy 12C6+ ion beam in a dosedependent manner, and the NBT reduction of vascular rings increased dose-dependently (P <0.05 at 4.0 Gy, P <0.01 at 6.0 Gy vs control group). Adding exogenous SOD before irradiation could significantly inhibit the increasing of NBT reduction (P<0.01), and also had protective effect on vascular endothelium dependent diastolic function (P<0.01), but 10 min after irradiation with exogenous SOD, its protective function was significantly less than before. Conclusion indicated that 12C6+ ion beam irradiation could cause endothelial function impaired, O2􀀀 scavenger SOD has a protective effect on endothelial dysfunction, suggesting that O2􀀀 mediates endothelial injury induced by heavy ion irradiation.     

HIRFL-CSR实验环中束流损失机制及寿命研究

分析了在储存环中回旋的离子束与残余气体分子、 内靶和冷却电子束相互作用时的损失机制及相应的束流寿命, 针对兰州重离子加速器冷却储存环实验环内靶模式, 计算了50—500 MeV/u 12C6+, 36Ar18+, 132Xe54+和 238U92+等束流在各种损失机制影响下所对应的束流寿命和总的束流寿命。 结果表明: 影响束流寿命的主要因素是与内靶分子（原子）之间的电荷交换及与冷却电子束之间的辐射复合; 对于重离子束 132Xe54+和 238U92+, 与冷却电子束之间的辐射复合是影响其储存寿命的主要因素。The loss mechanism and lifetime of ion beams in collisions with residual gas, internal target and electrons in e cooler in heavy ion cooler storage rings were studied. The partial beam lifetimes resulting from various loss mechanisms and the total beam lifetimes of 50—500 MeV/u12C6+, 36Ar18+, 132Xe54+ and 238U92+ stored in the experimental ring of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL CSR) were calculated. The calculations indicate that the charge exchange process between ion beams and the internal target, as well as the radiative recombination process with the electrons in e cooler restrict the beam lifetime considerably. For heavy ion beams such as 132Xe54+ and 238U92+, the radiative recombination is the dominant loss mechanism     

Influence of a centered dielectric tube on inductively coupled plasma source: Chamber structures and plasma characteristics

A high-density RF ion source is an essential part of a neutral beam injector. In this study, the authors attempt to retrofit an original regular RF ion source reactor by inserting a thin dielectric tube through the symmetric axis of the discharge chamber. With the aid of this inner tube, the reactor is capable of generating a radial magnetic field instead of the original transverse magnetic field, which solves the E × B drift problem in the current RF ion source structure. To study the disturbance of the dielectric tube, a fluid model is introduced to study the plasma parameters with or without the internal dielectric tube, based on the inductively coupled plasma(ICP) reactor. The simulation results show that while introducing the internal dielectric tube into the ICP reactor, both the plasma density and plasma potential have minor influence during the discharge process, and there is good uniformity at the extraction region. The influence of the control parameters reveals that the plasma densities at the extraction region decrease first and subsequently slow down while enhancing the diffusion region.     

GANRA-5对X射线和~(12)C~(6+)离子辐射防护作用研究

研究了一种新的恶唑酮类衍生物GANRA-5对于人胚肺细胞MRC-5的辐射防护作用。以MTT评价其对于细胞的毒性,以γH2AX foci形成法检测其对于辐照后细胞中双链断裂的影响,发现其对于受到X射线和12C6+离子照射的细胞具有较强的辐射防护作用,并进一步发现其能够显著清除辐照后细胞内的自由基。这些结果表明,GANRA-5具有较低的细胞毒性,并能够通过清除自由基发挥较强的针对X射线和12C6+离子的辐射防护作用,有望开发为高效的辐射防护药物。     

12C6+离子对阿维链霉菌累进辐照诱变效应研究

选用12C6+ 离子束对阿维链霉菌诱变选育高产菌株与原始菌株进行辐照诱变, 研究其累进辐照效应。实验结果表明,在辐照剂量为10 Gy时, 原始菌株比诱变高产菌株存活率高, 抗辐射能力强;辐照剂量高于30 Gy时,诱变高产菌株比原始菌株存活率高, 抗辐射能力强。原始菌株正突变率最高的辐照剂量为50 Gy, 致死率99.43%,正突变率最高, 达34.2%;对诱变高产菌株辐照剂量为30 Gy,致死率94.97%,正突变率最高, 达23.5% 。累进辐照效应降低了最佳辐照剂量。 Mutagenic effect on the mutant high producing strain ZJAV Y1 203 and the original strain ZJAV A1 irradiated by ion beam of 12C6+ have been investigated. The experimental results indicated that the original strain has higher survival rate and stronger resistance to radiation than mutant high producing Strain at dose of 10 Gy. The mutant high producing strain has higher survival rate and stronger resistance to radiation than the original strain at the dose higher than 30 Gy. The lethality was 97% and the highest rate of orthomutation was 34.2%, when ZJAV A1 was irradiated by 50 Gy 12C6+ beam. The lethality was 94.97% and the highest rate of orthomutation was 23.5% when ZJAV Y1 203 was irradiated by 30 Gy 12C6+ beam. The best radiation dose is decreased by progressivity irradiation.     

Ni2+掺杂和卤素空位填充协同抑制CsPbBr3纳米晶体中的离子迁移

卤化铅钙钛矿(LHPs)由于具有优异的光电性能和制备成本低等优点,已成为新一代光电器件的有力候选材料。然而,缺陷造成的离子迁移会导致LHPs纳米晶的晶体结构解离分解。因此,稳定性成为LHPs实际应用中亟待解决的问题。本文旨在研究镍离子替位掺杂及卤素空位填补对CsPbBr3纳米晶中的离子迁移抑制作用。通过离子迁移活化能的测定和高分辨透射电镜的原位观察,分析了前驱体掺杂剂对加强LHPs稳定性的作用原理。首先,选用乙酰丙酮镍和溴化镍作为掺杂剂,合成了掺杂LHPs纳米晶。其次,通过吸收-荧光光谱,X射线衍射,X射线光电子衍射,透射电子显微镜等测试手段对掺杂样品的光学及化学组成进行分析。最后,通过纳米晶薄膜电导率的温度依赖关系计算出其离子迁移活化能,并结合高分辨电镜原位观察纳米晶在高能电子束辐照下的形貌演变过程,揭示了不同掺杂剂对合成掺杂LHPs稳定性的影响。实验结果表明:Ni²⁺掺杂CsPbBr3样品的离子迁移活化能相较本征CsPbBr3样品(0.07 eV)有显著提升,其中乙酰丙酮镍掺杂样品的离子迁移活化能为0.238 eV,溴化镍掺杂样品的离子迁移活化能为0.487 eV。另外,电子束辐照测试表明溴化镍掺杂钙钛矿晶体表现出更高的结构稳定性,这主要归因于掺杂的Ni²⁺对卤素的强结合和卤素填补空位缺陷的协同钝化作用。Ni²⁺掺杂和卤素空位填充协同可以有效抑制卤化物钙钛矿纳米晶体中的离子迁移。     

12C6+离子束辐照黄花蒿干种子当代生物学效应

利用12C6+重离子束对黄花蒿干种子辐照后,利用发芽率、根长、下胚轴长和株高4个指标研究不同剂量12C6+离子束辐照对黄花蒿的生物学效应。结果表明,随着辐照剂量的增加,黄花蒿的存活率和根长都呈现逐渐降低的趋势,而下胚轴长先上升后下降,株高总体呈现下降的趋势,但在60和90 Gy同时存在矮化与增高的植株。利用SRAP （sequence related amplified polymorphism）技术对辐照后M1代的黄花蒿植株进行研究,结果表明对照组和处理组之间的差异体现为特异性条带的变化。综合分析表明,12C6+的重离子辐照黄花蒿干种子可以产生显著的当代损伤效应,同时引起植物DNA的多态性变化。     

12C6+离子束诱变水稻籽粒Cd低积累突变体的研究

筛选低Cd积累水稻品种是控制稻米Cd含量的最直接有效的办法之一。本研究对重离子辐照的中籼9311（Oryza sativa L）后代,利用石墨炉原子吸收光谱法检测,对曝露在不同Cd含量（含Cd量为19.8 mg·kg-1镉池和含Cd量为2.721 mg·kg-1的污染农田）中进行M2代Cd低吸收突变单株筛选,研究重离子辐照水稻籽粒Cd吸收的突变率以及比较不同Cd含量曝露下的筛选效率。结果显示:重离子辐照可以诱发水稻籽粒Cd积累量的变异,其突变频率为3:398%±0:009（P<0:05）;初筛获得78株籽粒较WT Cd吸收差异显著的突变体,进一步对其种植,分析M3代籽粒Cd含量。结果表明,重离子辐照诱变水稻突变体突变率高,遗传稳定,高Cd含量曝露下筛选效率更高,突变体水稻籽粒中Cd的积累存在着明显的差异,产生Cd积累差异的基因型丰富;相关性分析表明,M2代和M3代糙米中Cd含量存在显著相关性r=0:8210（P<0:01）,M3代获得23株遗传性良好且Cd含量差异显著的突变体水稻,其中Cd含量低于国家标准0.2 mg·kg-1突变体3株。表明筛选出的水稻突变体,在吸收转运Cd的过程中,存在差异且能稳定遗传,可供进一步研究培育籽粒Cd低积累的水稻品种。Screening low-cadmium rice cultivar is the most directly and effective way to control cadmium content in rice grain. We screened low-cadmium rice mutant of M2 generation exposed in different Cd concentration (the pool contaminated with 19.8 mg Cd·kg-1 and the paddy field contaminated with 2.721 mg Cd·kg-1) from rice mutants(9311, Oryza sativa L) induced by 12C6+ ion beam, and explored the mutation rate of 12C6+ ion beam irradiation and the screening efficiency of different Cd concentration exposed, all of the detections were carried out by Graphite Furnace Atomic Absorption Spectrum(GFAAS). The results showed that the mutation rate is 3:398%±0:009(P<0:05) and high Cd concentration exposed has more efficiency in screening low-Cd rice mutant. Correlation analysis show significant correlation of Cd in rice grain between M2 and M3 generations, r=0:8210(P<0:01); We obtained 23 mutant strains with significant Cd concentration difference and they had a great genetic stability. Among them, three strains' Cd concentrations were lower than the national standard (0.2 mg·kg-1). They can used for further study on cultivating new rice varieties of low Cd accumulation in rice gain.     

姜黄素对重离子辐射损伤小鼠睾丸组织的防护作用研究

探讨姜黄素(Curcumin,简称Cur)对重离子辐射损伤小鼠睾丸组织的防护作用。小鼠灌胃不同剂量的Cur后给予4 Gy剂量~(12)C~(6+)离子束全身单次照射。24 h后对小鼠睾丸组织形态学变化进行观察,并测定丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性。结果显示:中、高浓度Cur预处理组对小鼠睾丸组织的形态具有较好的保护作用;低、中浓度Cur预处理组MDA含量显著降低(P0.05);与单纯照射组相比,低浓度Cur预处理组SOD活性水平和中浓度Cur预处理组CA了活性水平显著提高(P0.05)。结果表明:Cur对重离子全身辐射小鼠的抗氧化系统有一定的激活效应,对辐射损伤有一定的防护作用,其机制可能与Cur清除自由基,保护脂质和蛋白质有关。     

Ionic conductivity and phase stabilization in Cu- and Tl-substituted CsAg2I3

Samples of general formula CsAg_2−xM_xI₃, x=0–0.4 and M=Cu and Tl, have been prepared and studied by powder X-ray diffraction, DSC and electrical conductivity measurements. X-ray diffractograms and DSC curves showed the possibility of stabilizing the high-temperature -phase at lower temperatures in Tl-substituted samples, while such results were not obtained in Cu-substituted samples. Ionic conductivity measurements showed two regions corresponding to the low- and high-temperature phases. The transition temperature between the two phases was found to remain unchanged with the addition of Cu⁺ and decreased gradually with increasing Tl⁺. The ionic conductivity decreased in Cu-substituted samples and enhanced with the incorporation of Tl⁺ ion in the lattice of CsAg₂I₃. Dielectric constant was found to show behaviour similar to that of the ionic conductivity, and this is an evidence of the predominant effect of ion hopping on this property.     

基于FRET机理的荧光探针的合成及其对汞离子的识别

基于FRET机理设计合成了一个包含罗丹明6G及香豆素的汞离子荧光探针Rh-6G-coumarin(RC),研究了它的光谱性能及对汞离子的识别作用。在V(C₂H₅OH)∶V(H₂O)=9∶1溶液中加入汞离子后,575 nm处荧光强度迅速增大,荧光由蓝色变为明亮的红色,同时溶液的颜色由黄色变为红色。溶液中其他金属离子,如Na⁺、K⁺、Mg²⁺、Fe²⁺、Co²⁺、Pb²⁺、Zn²⁺、Cd²⁺和Cr³⁺对汞离子的荧光识别没有太大影响。该探针可在较宽的pH ( 4~10)范围内识别汞离子。光谱滴定实验表明,汞离子与RC以2∶1的计量比形成了配合物。