最新刊期
      期 6 ， 2004
      • SHEN Bo,JU Guizhi
        Vol. 22, Issue 6, Pages: 321-324(2004)
        摘要：RNA interference is an typical gene regulation pathway. The article focuses on the mechanism and the mediate role of siRNA. Being a potentially powerful tool to study specific gene function, the mechanism of cellular defense and the efficiency RNA surverillance, RNAi technology will be applied in radiobiology to provide effective tools for not only the research of radiosensitivity and radiation damage, but also radiotherapy.  
        关键词：RNAi;siRNA   
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        发布时间：2023-03-30
      • HOU Zhengchi,SUN Dakuan,QIN Zongying,JIN Jiang,ZHU Liandi,YAO Side,SHENG Kanglong
        Vol. 22, Issue 6, Pages: 325-328(2004)
        摘要：High dose irradiation by ionizing radiations kills effectively micro-organism pathogen in foods, in order to ensure food safety and prolonged shelf life. In this paper, fresh pork loin samples were treated with methods of protein enzyme inactivation at 72℃, vacuum packing and freezing temperature irradiation of 60Co γ-rays, so as to minimized effects of radiation chemical reactions during the radiation processing. SDS gel electrophoresis and other analyses were done on the irradiated samples. The results show that up to 45kGy irradiation at (-20±5)℃ the samples generates no significant impairment in the protein quality, despite minor structural changes in the proteins. The amino acid contents remained almost the same, whereas retentive rates of vitamin B1 and B2 were about 22% and 61%, respectively.  
        关键词：Radiation processing;Enzyme inactivation;Vacuum package;Low temperature irradiation;SDS gel electrophoresis   
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        发布时间：2023-03-30
      • JIA Shaojin,XU Zhongting,ZHANG Zhicheng,JIANG Pingkai,XIU Qihui,WANG Zongguang
        Vol. 22, Issue 6, Pages: 329-333(2004)
        摘要：High-density-polyethylene (HDPE), Si rubber (SR) and ethylene-density-polyethylene (EPDM) were used as the polymer matrices, A kinds of carbon blacks was used as the conductive filler. The positive temperature coefficient (PTC) intensity of the HDPE/CB, HDPE/EPDM /CB composites flow during extrusion to produced was tested before and after irradiation. Compared to that of HDPE/CB composites, the electrical reproducibility of the irradiated HDPE/EPDM /CB composites of is better. The effects of γ-rays irradiation were also estimated. The results showed that the reproductive of the PTC effect was related to the adhesion between the interface of the polymer matrices and CB particles. These PTC phenomena and their distinctive aspects were described. The explanations were given from the structural characteristics of the blends, CB particles distribution and motion of polymer segments.  
        关键词：High-density-polyethylene (HDPE);Negative temperature coefficient (NTC);Positive temperature coefficient (PTC) intensity;Si Rubber;Carbon black   
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        发布时间：2023-03-30
      • WANG Shilong,ZHANG Zhen,LI Min,SUN Xiaoyu,LI Wenzhe,NI Yaming,WANG Wenfeng,YAO Side
        Vol. 22, Issue 6, Pages: 334-338(2004)
        摘要：Pulse radiolysis of aqueous quinoline in dilute solutions under different conditions was studied. The main characteristic peaks in the transient absorption spectra were attributed and the build−up/decay trends of several transient species were investigated. Under alkaline conditions, interactions between OH radicals and quinoline molecules yield OH−adducts with a rate constant of 5.5×109 L/mol−1 s−1. Under acidic conditions, quinoline molecules react with H+ radicals to form quinoline cations, which react with OH radicals to yield quinoline cation OH−adducts with a rate constant of 7.90×109 L/mol−1 s−1. The reaction mechanism of OH in alkaline conditions and in neutral conditions are the same, the rate constant in neutral condition is 7.15×109 L/mol−1 s−1. The reaction of H with quinoline produces H–adduct. In neutral solutions, eaq− react with quinoline and produce quinoline anion with a rate constant of 7.05×109 L/mol−1 s−1.  
        关键词：Quinoline;Pulse radiolysis;Transient species;OH radical   
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        发布时间：2023-03-30
      • WANG Dehai,CHEN Xiaofang
        Vol. 22, Issue 6, Pages: 344-348(2004)
        摘要：Effects of pigment modification to change pigment/binder interfacial characteristics and UV curing behavior were studied. The results show that the air absorbed on surface of the pigment plays an important role in hindering UV curing. In addition, there obviously exists the interface coupling effect between the pigment and the binder via the modifier of the pigment (reagent TEA). ESEM studies revealed that wetting property of the pigment was improved and binding between the pigment and the resin was strengthened after the pigment modification. EDS data showed an obvious enrichment of O−containing group of modification agent (−OH) in the interface and a shift of binding energy of the modifier was also detected. This may also contribute to the increase of curing proficiency due to the priority of the absorption of UV energy by the modifier TEA to that of pigment. The work demonstrated that the pigment modification could be used as a method to improve the UV curing efficiency. In the case of TEA, the curing rate of blue pigmented UV curable coating (125μm) could be improved greatly (from 45s to 14s). The study have shown a promising application of various kinds of fillers as well as pigment in UV coatings.  
        关键词：Pigment;Modification;UV curing;Interface   
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        发布时间：2023-03-30
      • ZHU Guangming,XU Shuogui,FEI Jingyin,QIN Ruifeng,LIANG Guozheng
        Vol. 22, Issue 6, Pages: 349-355(2004)
        摘要：The nonisothermal crystallization kinetics of radiation crosslinked poly (ε-caprolactone) (PCL) were investigated by differential scanning calorimetry with different cooling rates. The features of crystallization process were analyzed using Ozawa equation and Mo Zhishen method developed by combining Avrami equation and Ozawa equation. The results showed that the crystal fraction and crystallization rate were related to the cross-linking degree and radiation dose, the relation between ln[-ln(1-Xt)] and lnQ follows the Ozawa equation and the plot of lnQ vs. ln(t) follows Mo’s formula. The way of crystalline growth of radiation crosslinked PCL belongs to heterogeneous nucleation and single-dimension model. By using an evaluation method proposed by Kissinger, activation energies of nonisothermal crystallization for radiated PCLs with different radiation dose have been evaluated to be between 54 kJ/mol and 64 kJ/mol.  
        关键词：Polycaprolactone;Radiation cross-linking;Nonisothermal crystallization;Kinetics   
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        发布时间：2023-03-30
      • LI Yuguo,NI Jin,HAN Ling,ZHAO Qunfen,GAO Fu,LI Qingnuan,XU Jingying,LI Wenxin
        Vol. 22, Issue 6, Pages: 356-360(2004)
        摘要：The UV radioprotcetive effect of fullerols, which was compared with the effect of C60-PVP, was studied using cultured L02 cells. The cell survivals were determined by MTT method, SOD and MDA also were studied with chemistric colorimetry. The results showed that fullerols can effectively protect cells from damage induced by UV irradiation. The mechanism could be assosiated with the ability of fullerols to behave as an antioxidant compound, then fullerols protected cell membrane from damage by UV radiation.  
        关键词：Fullerene;Ultraviolet radiation;Radioprotective.   
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        发布时间：2023-03-30
      • FAN Yan,WU Shiliang,XU Lan,CHEN Keping,QIU Hao
        Vol. 22, Issue 6, Pages: 361-364(2004)
        摘要：To observe the effect of γ-irradiation and UV on the mRNA expressions of ppGalNAcT2 (polypeptide N-acetylgalactosaminyltransferase-2) in K562 leukaemia cells and study the relation of ppGalNAcT2 to tumor’s generating and developing. K562 cells were exposed to different doses of γ-rays and ultraviolet, the expressions at mRNA level of ppGalNAcT2 were examined by reverse transcription polymerase chain reaction (RT-PCR) within 12h. The results showed that the mRNA expressions of ppGalNAcT2 decreased evidently in two irradiated groups, and they were negatively relative to the dosage. The mRNA expressions of ppGalNAcT2 in K562 leukaemia cells could be inhibited by radiation , it is postulated that ppGalNAcT2 might relate to some biological specificity of cancer cells, such as tumor’s invasion and migration.  
        关键词：γ-irradiation;ultraviolet;K562 leukaemia cells;ppGalNAcT2   
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        发布时间：2023-03-30
      • LUO Jialin,CAO Jianping,ZHU wei,LIU Fenju,WANG Mingming,ZHOU Xianfeng,ZHU Caiying,ZHENG Siying
        Vol. 22, Issue 6, Pages: 365-369(2004)
        摘要：The high radiosensitivity of fibroblast cells (AT5BIVA cells) from the skin of the Ataxia- telangiectasia (A-T) patients were studied. Using Hypoxanthine phospho-ribosyl transferase gene mutation analysis and Cytokinesis-Block micronucleus method, the hprt mutation frequence(hprtMF), the micronucleus frequencies (MNF)and micronucleus cell frequencies(MNCF)of AT and GM cells irradiated with 0, 1, 2, 3 and 4Gy of 60Coγ-rays were observed. The difference of hprtMF, MNF and MNCF between AT and GM cells were analyzed, and dose-response curves of hprtMF, MNF and MNCF in AT and GM cells were also established. After exposure to 0, 1, 2, 3 and 4Gy of 60Coγ-rays, hprtMF, MNF and MNCF were significantly higher in AT cells than those in GM cells(p<0.01). In the two cell types, hprtMF MNF and MNCF had a positive correlation with dose, and their linear regression equations were y=a+bx. These results show that the radiosensitivity of AT cells is significantly higher than that of GM cells and AT cells are extremely sensitive to radiation.  
        关键词：Ataxia-telangiectasia;High radiosensitivity;Hypoxanthine phospho-ribosyl transferase;Cytokinesis- Block micronucleus method   
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        发布时间：2023-03-30
      • YU De,TIAN Ye,DING Weijun,ZHU Yaqun,LIU Chunfeng
        Vol. 22, Issue 6, Pages: 370-374(2004)
        摘要：To investigate the change pattern of some inflammatory cytokines in brain tissue at the acute phase after brain irradiated. The whole brain of SD rats was irradiated by the single dose of 2, 15, or 30Gy of 4 MeV electron beam. The enzyme−linked immunosorbent assay (ELISA) was used for the measurement of IL−1 β, IL−6, and TNF−α content in hippocampus tissue of rats at 1h, 6h, 12h, 1d, 2 and 1week post−irradiation. The mRNA of IL−1 β, IL−6, and TNF−α were detected by reverse−transcription polymerase chain reaction (RT−PCR) in the same experimental groups. It was analyzed about the influence of dosage and post−irradiation duration with the cytokines expression. Compared with both the normal control and the anaesthetized with chloral hydrate but sham−irradiation groups, there were no difference about the three inflammatory cytokines expression in rats with 2Gy irradiated. At 6h after irradiation with 15Gy, 6 and 12h with 30Gy groups, the content of IL−1 β and TNF−α in hippocampus tissue were significantly increased, and were returned to normal level after 12 to 24h. The same change tendency of their mRNA relational level was observed in 15 and 30Gy groups, but it happened earlier in 1h after exposure. Although the content of IL−6 in hippocampus kept stable in all the groups, its mRNA level raised obviously in 12h group. After 15—30Gy whole−brain irradiation, the expression of some inflammatory cytokines increased abruptly in the hippocampus of SD rat within 1 day, but the interplay between inflammatory cytokines changes and the pathogenesis of radiation injury was incompletely understood at present.  
        关键词：Brain;Radiation;Inflammatory cytokines;Hippocampus;Rat   
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        发布时间：2023-03-30
      • ZHANG Wenyi,JIAO Ling,HOSHI Masaharu
        Vol. 22, Issue 6, Pages: 375-377(2004)
        摘要：Dry dormant onion seeds were irradiated by 0.2MeV neutrons from an accelerator, or 60Co γ-rays, for a better understanding of relative biological effectiveness (RBE) of mono-energy neutrons, and for observing different frequencies of micronuclei in root-tip cells of the onion seedlings induced by unit dose of the neutrons and γ-rays. The frequencies of micronuclei induced by unit dose of the 0.2MeV neutrons and the 60Co γ-rays are 5.36±0.30 and 0.031±0.002 (%Gy-1), respectively. The RBE value for the 0.2MeV neutrons is about 173±15, using the 60Co γ-rays as reference radiation. The RBE value of the 0.2MeV neutrons to induce micronuclei in the root-tip cells of Allium cepa onion seedlings irradiated as dry dormant seeds is as high as 173±15. Our findings suggested that the repair efficiency of DNA damage induced by mono-energetic neutrons might be different from those by γ-rays.  
        关键词：Neutron;Micronucleus;Onion seed;Relative biological effectiveness (RBE)   
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        发布时间：2023-03-30

        研究论文

      • ADELEKE O. Francis,ZHOU Ruimin,ZU Jianhua,HE Linfeng
        Vol. 22, Issue 6, Pages: 339-343(2004)
        摘要：Electron beam was used for degradation of aqueous solutions of 2−chlorophenol (2−CP), 4−chlorophenol (4−CP), and 2,4−dichlorophenol (2,4−DCP) in this research. The effect of absorbed dose on substrate degradation, dechlorination and pH of solutions with an initial concentration of 200mg/L each and another solution containing 50mg/L each of the three solutes mixed together were investigated. The results show that increased dose leads to increased degradation of the chlorophenols, increased Cl－ yield and decreasing pH value of the solutions. For the individual solutions containing 200mg/L of solutes, the rate of degradation and chloride ion yield was in the order of 2,4−DCP>4−CP>2−CP, while for the mixed 50mg/L solution, while 2,4−DCP still has the highest degradation rate, the degradation of 4−CP and 2−CP proceeded almost at the same rate. At a dose of 21kGy, the rate of degradation were 93.0% for 2−CP, 98.5% for 4−CP and 99.4% for 2,4−DCP (200mg/L individual solutions), and the chloride yield was 55.4%, 71.3% and 69.0% for 2−CP, 4−CP and 2,4−DCP respectively. The calculated dose required for 90% degradation of the original solute (D90) are 18.0kGy (2−CP), 11.4kGy (4−CP) and 6.1kGy (2,4−DCP) for the 200mg/L solutions and 16.1kGy (2−CP), 15.6kGy (4−CP) and 12.8kGy (2,4−DCP) for the 50mg/L mixed solution.  
        关键词：Electron beam;Chlorophenols;Degradation   
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        发布时间：2023-03-30
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