最新刊期
      期 1 ， 1983
      • Lin Nianyun,Li Xuepeng,Tu Tiecheng,Xie Jidong
        Vol. 1, Issue 1, Pages: 1-7(1983)
        摘要：In order to investigate the charge transfer protection mechanism on DNA and its electrophilic nucleotide-dTMP, caffeic acid (DHPAA) and methyl caffeate (MDHPA)protectors have been studied in detail. DHPAA and MDHPA belong to phenylsubstituted unsaturated carboxylic acid, thus, their E A may be as high as maleic or fumaric acid and their energies of lowest empty molecular orbitals are 1.79eV、1.75eV respectively and lower than that of thymine (2.60eV) and cystine (2.02eV). Besides, caffeic acid and bases of nucleotides form long chain of stacked arrays which is beneficial for long range electron transfer from pyrimidine anion to electrophilic acceptor-DHPAA or MDHPA. These predictions are strongly confirmed by ESR studies. The ESR spectra from dTMP-DHPAA (g=2.0041, Hpp=15.38G) and dTMP-MDHPA (g=2.0043, Hpp=14.33G) with minor molar radio of DHPAA or MDHPA to dTMP 1:10, irradiated and recorded at 77K, reveal characteristic similar to that from DHPAA (g=2.0042, Hpp=13.72G) or MDHPA(g=2.0043, Hpp=13.44G), which represent carboxylic anion radical alone, and different from dTMP (g=2.0040, Hpp=24.45G). After annealing at room temperature the ESR patterns changed into that from DHPAA or MDHPA alone at room temperature and no traces of ESR signal from 5-thymyl radical could be found. Regarding the binary systems of DNA-DHPAA. DNA-MDHPA with minor molar ratio of protector to nucleotide (1:4), ESR spectra from DNA-DHPAA (g=2.0034, Hpp=18.72G)、DNA-MDHPA (g=2.0034, Hpp=19.40G) also reveal the characterisitic similar to that from DHPAA or MDHPA alone, irradiated and recorded at 77K. After annealing at room temperature these ESR patterns also changed into that from DHPAA or MDHPA alone at room temperature and no traces of the well known octet pattern from 5-thymyl radical coulal be found.  
        关键词：Charge transfer;ESR;DNA;Caffeic acid;Methyl caffeate   
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        发布时间：2023-04-18
      • Sun Jiazhen
        Vol. 1, Issue 1, Pages: 8-16(1983)
        摘要：By comparison of the adaptability of the relationship of Charlesby-Pinner and Chen-Liu-Tang, the affection of polymer structure on its behaviour in radiation induced crosslinking was studied.The rigid chain polymer with higher Tg (glass transition temperature) and σ (hindrance factor of internal rotation) value and the polymer, containing some structure unit of radiation degradation type, obey Charlesby-Pinner relationship. The branched polymer and the flexible chain polymer with lower Tg and σ value obey Chen-Liu-Tang relationship.  
        关键词：Charlesby-Pinner relationship;Chen-Liu-Tang relationship;Rigid chain polymer;Flexible chain polymer;Branched polymer;Radiation induced crosslinking;Polymer structure;Glass transition temperature;Hindrance factor of internal rotation   
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        发布时间：2023-04-18
      • Qi Shengchu,Shen Qinzhang,He Yongke,Wu Jilan
        Vol. 1, Issue 1, Pages: 17-25(1983)
        摘要：The radiolysis of the dilute aqueous solution of cyanide ion in N2-containing system has been investigated. The yields of the main radiolytic products are as follows:It may be considered that urea can be formed by the following reaction(1)in this case, G(CNO-) equals 0.50.The Main radiolytic products under O2-lacking conditions also has been investigated. The experimental results and kinetic calculations show that cyanate and formamide can be formed not only by the disproportionative reaction (3).(3)but also by the reactions (9) and (11)(9)(11)where H2CN and HCN- radicals were formed by the reactions of H atom and hydrated electron with HCN.The contributed G(CNO-) values are 0.36 and 0.14 for the reactions (3) and (9)respectively. The presented G(HCONH2) values from the reactions (3) and (11) are 0.36 and 0.64, separately. The rate constants have been determined: M-1sec-1 from the variations of G values of cyanate versus formate concentrations and 2.8×109M-1sec-1 from that of formamide. By using ethanol as scavenger, value has been determined, which is equal to 1.7×109M-1sec-1. All the values agree well with the published data. The exprimental result also show that the formation of glycine is related to hydrated electron and the formaldehyde is formed by spur reaction.The unknown (Rf=0.21) seems to be related to the intermediate product formed by the reaction of hydrated electron with HCN. From the material balance, estimated value is equal to 4.5, which is consistent with the experimental value 4.3±0.3.  
        关键词：Radiolysis of aqueous KCN solution;Formate radical scavenger;Formation of glycine;Formation of formamide;Formation of cyanate   
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        发布时间：2023-04-18
      • Lin Nianyun
        Vol. 1, Issue 1, Pages: 26-34(1983)
        摘要：Concerning the primary radiation processes of DNA and radiation modifiers a fast radiation protection mechanism — charge transfer protection hay been supposed. Some binary molecular mixtures, such as thymine-cysteine, thymine-histidine or arginine, dTMP-caffeic acid, DNA-caffeic acid etc. have been studied in detail by means of ESR and other related methods. A proposed general scheme involves basically charge transfer oxidation/reduction processes. If the electron affinity (EA)of protector (P) or sensitizer(s) is larger than target molecule (TH), i. e., EAP.S>EATH(Ⅰ) and IPP.S≲IPTH(Ⅱ), thus, (Ⅰ) and (Ⅱ) may behave additively to protect TH. On the contrary, if IPP.S≳IPTH(Ⅲ), then, (Ⅰ) and (Ⅲ) may behave synergistically to sensitize the damage of TH. The common characteristic of charge transfer protection and sensitization is (Ⅰ) and their criterions are (Ⅰ) and (Ⅲ), that is to say, the charge transfer protector is a substance with higher EA but lower IP than TH. However, charge transfer sensitizer is a substance with both higher EA and IP than TH. In accord with above scheme we have found a qualitative rule relating the radiation protection effect to the linear molecular size of linear aromatic homologs: the larger the molecular size, the lower the IP, the higher the EA, thus, the higher the transfer efficiency through charge transfer to these aromatic protectors. These linear aromatic homologs may be examined as a model of charge transfer protector to suppress chemical carcinogenesis and protect the radiolysis of TBP-alkane extraction system. Furthermore, development of H-transfer paocess has been achieved based on the detailed examination of thymine-cysteine and thymine-AET. Further exploration of excitation transfer between thymine and aromatic amino acid has also been demonstrated.  
        关键词：Charge transfer;H-transfer;Excitation transfer;DNA;Electrophilic amino acids;Caffeic acid protectors;Nitro-aromatic sensitizers;Linear aromatic protectors   
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        发布时间：2023-04-18
      • Zhang Jiashan,Qin Guoliang,Zhang Wenlong
        Vol. 1, Issue 1, Pages: 35-43(1983)
        摘要：The mechanism of the dimerization of thymine in frozen aqueous solutions induced by γ-rays was described. During the study of dynamic mechanism of the dimerization, it was found that the thymine dimer linked by a cyclobutyl ring is formed by way of excited triplet state mechanism at lower concentration of thymine but by way of mechanisms of excited triplet state and excited aggregating state at higher concentration of thymine. These mechanisms agree with following dynamic equations respectively:In this paper, some dynamic parameters are given and the sources to form excited state of thymine are discussed.  
        关键词：Dimerization of thymine;Triplet state;Aggregate state;Frozen aqueous solution   
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        发布时间：2023-04-18
      • Rong Yong,Shen Longcai,Li Wenke,Gao Faben,Guan Shuqing,Sun Gongqi,Jiang Yonglu,Zhang Yinglan,Mu Jinchai,Zhang Jiaqiang,Guo Guizhen
        Vol. 1, Issue 1, Pages: 44-49(1983)
        摘要：This paper described a pilot process of polymerization of acrylamide in middle concentration (30~35% by weight) aqueous solution with the additive disodium EDTA. The whole process is divided into four parts:1.The preparation system (including preparation of monomer, additive and other things before irradiation).2. The transportation system (for carring monomer and product).3.The radiation polymerization system (including γ-rays irradiation facilities).4.The product treatment system.The intensity of 60Co source used was 45000Ci and the polymerization capacity of this set is about 30 ton/year now. There are three kinds of products: non-ionic, ionic and crosslinking. They have successfully been used in petroleum, metallurgy, coal, and other fields, Good results were ohtained.  
        关键词：Polyacrylamide;Radiation polymerization;Pilot process;Acrylamide   
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        发布时间：2023-04-18
      • Tang Guoqiang,Liu Yuming
        Vol. 1, Issue 1, Pages: 50-56(1983)
        摘要：This article reports the γ-ray induced copolymerization of chlorotrifluoropropene(CTFE), ethylene(E) and hexafluoropropene (HFP) in trifluorotrichloroethane (FC-113)served as solvent. It was mainly discussed how the reaction conditions affected the properties of terpolymer such as its composition, melting point, fused flowability, physicomechanical and hot-aging. The results are as follow:1. The content of hexafluoropropene in the terpolymer increases with the mole ratios HFP/CTFE and HFP/E in the monomer feed.2. When the value of mole ratio E/CTFE in the monomer feed is less than 0.65, and HFP/CTFE below 0.25, the melting point of the terpolymer will be≥235℃.3. A quantity of -CF3 pendant group connected with the backbone of the terpolymer would strengthen its fused flowability without decreasing its molecular weight. Therefore, the increase if M.I. has less influence upon its mechanical property. The relationship among the M.I., irradiation temperature(T), solvent feed froportion(ϕ)and hexafluoropropene content in the terpolymer(A) can be approximately shown by equation M.I.=10-3.8 • ϕ2.8 • T1.78•(41.7A)1.4.4. Compared with the copolymer E-CTFE, the terpolymer possesses much better hotaging properties, but those of electricity remain unchanged.  
        关键词：Radiation induced copolymerization;Fluoro-containing terpolymers   
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        发布时间：2023-04-18
      • Shen Yu
        Vol. 1, Issue 1, Pages: 57-63(1983)
        摘要：The importance of tumor radiobiology in radiotherapy, the content and advances of tumor radiobiology are briefly introduced.  
        关键词：Tumor radiobiology;Clinical radiobiology;Radiobiology;Radiobiological effect   
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        发布时间：2023-04-18
      • Wang Tianyu,Yang Lijun,Huang Qingtian
        Vol. 1, Issue 1, Pages: 64-68(1983)
        摘要：Based on the detailed experimental record and the statistical analysis of the data, we wish to put forward our concept on the micronuclei formation as follows: After irradiation the micronuclei were visible in the lymphocyte, their size is 1/3~1/2 of the main nuclei. The micronuclei were not derived solely from the fractions of the chromosome, but from the various components of the chromosome (such as acentric rings, microbodies, acentric fragments, various chromosome-containing mitosomes etc.) by fusing at various states and conditions in the cell plasma. Factors influencing the process of fusion include the allosteric change in membrane configuration of nuclei and of the kinetic status of the cell. According to the characteristic helical structure of DNA polynucleotide chain, we believe that under irradiation the acentric fragments of the double-nuclei lymphocyte showed a tendency to fuse leading to the formation of micronuclei. The way of micronuclei formation through fusion mechanism may be one of the main probabilities.  
        关键词：Lymphocyte;micronuclei formation;kinetic mechanism;membrane configuration;fusion   
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        发布时间：2023-04-18
      • Wang Ruqin,Wang Xiucheng,Li Jin,Zhang Baolin,Li Zhiwang
        Vol. 1, Issue 1, Pages: 69-73(1983)
        摘要：There were no changes of electrophoretic mobility (EPM) and 32P-incorporation rate in rabbit and rat erythrocytes 2 and 4 hrs after the irradiation of erythrocytes in vitro at 37℃ by γ-rays with doses of 250, 1000, 3000 and 5000 rad.However, the cell EPM decreased and the 32P-incorporation rate increased markedly 2 and 4 hrs after the total irradiation of rabbits or rats with 600 rad.The plasma taken from rabbits 2 and 4 hrs after irradiation could induce the similar changes in normal rabbit erythrocytes. Such activity of plasma from irradiated rabbit was preserved after inactivation by 56℃ for 15 min. cAMP level in rabbit plasma 2 and 4 hrs after irradiation increased and recovered to normal in 24 hrs.  
        关键词：Radiation effects;Cell membrane;Cell surface charge;Electrophoretic mobility (EPM);32P-incorporation rate   
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        发布时间：2023-04-18
      • Lin Wanmin,Ma Chengwu,Luo Zuyu
        Vol. 1, Issue 1, Pages: 74-79(1983)
        摘要：Using the agar diffusion chamber (ADC) for colony formation of lymphocytic leukemic cells L7712, we compared the survival curves of the cells irradiated by three kinds of low LET radiations — 200kV x-rays, 60Co gamma rays and 20 MeV electron beam in two rates (0.35Gy/min and 1.0Gy/min).The cells grew well in ADC both in the peritoneums of 615 inbred mice and Kumming white mice. The relationship between the number of cells implanted to each chamber and the number of colonies formed was shown to be linear. There was no significant difference between the two sets of data.200kV x-rays irradiation to cells was studied. The survival curve for a dose rate of 0.35Gy/min had a D0 of 1.55(1.45~1.67)Gy, n of 0 94(0.88~1.03) and correlation coefficient r= -0.88; while with a dose rate of 1.0Gy/min they were 1.39(1.30—1.54)Gy, 0.90(0.82~1.0) and -0.85 respectively. The D0, n and r for survival curve after 60Co irradiation (0.35Gy/min) were 1.76(1.60 ~1.90)Gy, 0.96(0.87~1.07) and -0.82. The RBE of 60Co gamma rays as compared with 200kV x-rays was 0.88. The survival curve for 20MeV electron beam (1.0Gy/min) had a D0 of 1.96(1.87~2.07)Gy and n of 0.99 (0.94~1.05), r=-0.93. Its RBE as compared with 200kV x-rays was 0 71.  
        关键词：Agar diffusion chamber;Clonogenic efficiency;Survival curve;Low LET radiation;Dose rate;Relative Biological Effectiveness (RBE);Mean lethal does (D0);Extrapolation number (n)   
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        发布时间：2023-04-18
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