最新刊期
期 1 ， 2001
- 摘要：In order to find the major reason for the radiation discoloration of PE, the changes of yellow index (YI) of HDPE and LDPE under γ irradiation in air or N2 and after irradiation are measured using colorimeter. The growth and decay of alkyl free radical formed in HDPE and LDPE, and the change of the absorbance of conjugated double bonds formed in PE are measured using ESR and UV —Visible spectrometer. The YI of HDPE is higher than that of LDPE at the same radiation dose. The YI of PE irradiated in air is higher than that of PE irradi¬ ated in N2 at the same radiation dose. The YI of PE irradiated different dose decreases with post—irradiation storage time firstly, up to a certain time, it becomes stable. It is found that the for¬ mation and decay of free radicals is very similar to that of the change of YI, whereas,the change of the absorbance of conjugated double bonds formed in PE is different to the change of YI. The results are discussed,it is believed that the major reason for the radiation discoloration is the for¬ mation of trapped free radicals.关键词：Polyethylene (PE);Radiation induced discoloration
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发布时间：2023-04-07 - 摘要：The reaction of tetraethylrhodamine with the active particals •OH,eaq-• and O2-• generated from the radiation of the aqueous solution are investigated by use of pulse irradiation technique. With plotting apparent first—order kinetic reaction simulated against concentration of it,the reaction rate constants of tetrarthylrhodamine with hydroxyl radical and aqueous electron have been determined. The reaction mechanism of tetraethylrhodamine containing in waster water by radiation technique is discussed.关键词：Tetraethylrhodamine;Pulse radiolysis;Transient absorption;•OH;eaq-•;O2-•
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发布时间：2023-04-07 - 摘要：For the super properties, elastomer materials have been widely using in the fields of industry, agriculture and national defense. But the weakness of aging resistance performance greatly affects its life span and increases the expenses for service. Some intensive research on the additives of antiager and antiozonant is carried out to improve the aging resistance of elastomers. But the property of elastomers aging resistance is not only related with the additives, but also with the curing methods. Radiation crosslinking method for curing the elastomers in this work is employed to modify the mechanical properties of elastomers SBR in order to enhance its aging resistance property.关键词：Elastomers;Radiation crosslinkinq;Aqinq resistance;SBR
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发布时间：2023-04-07 - 摘要：The process of edible gelatin irradiation sterilization has been studied,It conclude the dose relationship with dose heterogeneity, pile height and viscosity as well. The results demonstrated that the irradiation dose has negative correlation with viscosity, and positive correlation with sterilization effect,the dose heterogeneity, dose and the pile height should conform to H=R law. this study recommend that the best sterilization dose is 3—5kGy.关键词：Sterilization;Dose;D10 value;Viscosity
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发布时间：2023-04-07 - 摘要：Trioctyl phosphine oxide (TOPO) was used as the model of TRPO and its γ radiolysis was studied. The irradiated samples were dissolved in cyclohexane (CH),then extracted with 5% Na2CO3 and subsequently extracted with distilled water. Emulsification appeared in the process of water extraction. The extent of emulsification depended on the dose absorbed and pH of the system. It increased with the increasing of the dose absorbed, but the total G value decreased. The structures of radiolysis products were identified by IR spectra, UV spectra and element analysis. The results demonstrated that it was the oligomer of TOPO, phosphinic acid and its ester that induced emulsification.关键词：TOPO;γ radiolysis;Extraction;Emulsification;Oligomer
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发布时间：2023-04-07 - 摘要：Time - resolved pulse radiolysis and laser flash photolysis has been used to study the Photo—Fenton degradation of aniline. Using laser flash photolysis technique, it is demonstrated that aniline in aqueous solution is ionized by 308 nm photon to give hydrated electron and neutral radical resulting from rapid deprotonation of radical cation of aniline. The pKa value is found to be 7.5,and the quantum yield of the photo ionization is 0.08. Time - resolved pulse radiolysis has been used to study the reaction of aniline with •OH,and it was established that 36% •OH radical react directly with the - NH2 moiety resulting in anilino radical. The main primary process (54%) is the ortho — directed •OH — adduct. The remaining 10% •OH attack most probably the para position of the aniline ying.关键词：Aniline;Photo—Fenton degradation;Pulse radiolysis;Laser flash photolysis
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发布时间：2023-04-07 - 摘要：The rate constant of excited energy transfer in the γ radiolysis of CH—TOPO system was studied by final product analysis. The results showed that the rate constant for the system was 1.9×1010 L•mol•s-1, which was a little larger than that of an ordinary diffusion—controlled process.关键词：Cyclohexane (CH);Trioctyl phosphine oxide (TOPO);γ radiolysis;Energy transfer;Diffusion—controlled;Abnormal rate constant
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发布时间：2023-04-07 - 摘要：In this study, the survival of cultured Chinese V79 hamster cells irradiated with carbon ions with different LETs were investigated. Irradiation was performed at the Heavy Ion Research Facility in Lanzhou (HIRFL). Results were compared with those obtained from the experiments with γ rays and could be concluded as follows: The survival curves for carbon ions showed as straight lines and were fitted to the one—target one—hit model,but for γ rays the curves with shoulders were fitted to the multi—target one—hit model. As the LETs were 125, 200 and 700keV/μm for carbon ions, the inactivation cross section 35, 12 and 8μm2, respectively, which suggested that under the experimental conditions, the lower the LET of carbon ions, the more seriously the irradiation killed cells. In the case of 125keV/μm, the RBEs of carbon ions at the 0.1 amd 0.37 survival levels were 1.47 and 2.19 respectively.关键词：Linear energy transfer;Carbon ions;V79 Cell;Survival fraction;Inactivation cross section;Relative biological effectiveness
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发布时间：2023-04-07 - 摘要：: Using a charged particle microbeam whereby individual cell's cytoplasm could be irradiated with a single or an exact number of α particles, cell lethality, mutation induction and the functional role of reactive oxygen species in mediating the mutagenic response in the human—hamster hybrid (AL) cell assay system were assayed. The results showed that cytoplasm irradiation induced very little toxicity such that traversal through the cytoplasm with 16 alpha particles resulted in a cell survival fraction of —0.76. While cytoplasmic traversal with one particles induced relatively few CD59- mutant cells, those irradiated with 8 or more particles had an induced mutant frequency that was —3 fold higher than the background incidence. PCR analysis showed that CD59- mutation induced by cytoplasmic radiation involved almost exclusively small alterations similar to those of spontaneous origin. Treatment of cells with dimethyl sulfoxide(DMSO) suppressed the mutant frequency induced by cytoplasmic irradiation, whereas buthionine S—R—sulfoximine (BSO) treatment which reduces intracellular glutathione level,increased the mutation frequency. These novel findings showed that the mechanism of mutation by cytoplasmic irradiation was heavily dependent on oxyradicals. Moreover, using IF 7 monoclonal antibody to detect 8—OHdG induction, the data indicated that cytoplasmic irradiation generate oxidative DNA damage in the nuclei of the target cells.关键词：α particles;Cytoplasm;CD59 gene;Mutation;Reactive oxygen species
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发布时间：2023-04-07 - 摘要：The day—and—night rhythm changes in the contents of 5—HT of the brains and livers of mice treated by whole—body irradiation with 5Gy 60Co γ rays were investigated by means of fluorescent spectrophotometry. The results showed that compared with control, the 5—HT contents in both tissues, generally speaking, were increaased significantly after diurnal irradiation, but decreased insignificantly after night irradiation.关键词：5—HT;Day—and—night rhythm;60Co γ rays;Mouse
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发布时间：2023-04-07 - 摘要：The purpose of this study is to investigate the relationship between cell transformation and hprt gene mutation induced by α irradiation in vitro. The results showed that the colony formation efficiency (CFE) of human embryo lung cells in soft agar increased after irradiation with 0.25—5Gy, which meant inducible cell transformation by α irradiation. Mutation frequency of hprt gene was found increased with the increase of the doses of α irradiation. Further analysis indicated the positive linear correlation between CFE and the variation coefficient of hprt gene. So,the carcinogenesis induced by α particles maybe is relative to hprt gene mutation.关键词：α irradiation;Cell transformation;hprt mutation
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发布时间：2023-04-07 - 摘要：Low dose radiation (LDR) induced products were extracted from mouse spleen and its biological activity was preliminarily detected. The mouse spleen cells were sonicated and the induced products in the lysate were obtained with centrifugation. The method of radioactive isotope incorporation was used and the DPM as an index for evaluating the biological activity of the induced products, To investigate the possible influences of variant factors on the activity of the products, tests were carried out under different conditions: different time for extraction, different radiation doses, different volumes of extracted products for stimulation, and different radiation modes. Results showed that the transformation ability of mouse spleen cells was significantly enhanced after stimulation of these cells with LDR—induced products. And the above—mentioned changes in experimental conditions could influence the activity of the induced products to different extents. It was indicated from this study that the active LDR—induced products could be extracted 2—16h after irradiation with a dose range from 5 to 15cGy, and the effective composition of the induced products maybe belonged to newly synthesized protein.关键词：Low dose radiation;Induced products;Biological activity
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发布时间：2023-04-07 - 摘要：Mouse intestinal RNA was injected into the mice of the same strain within 1—3h after different doses of abdominal or whole body 60Co γ irradiation,so as to explore the initial effective time of mouse intestinal RNA and the affection of radiation condition on its restorative effect, by measuring the survival of mouse intestinal crypt. The results showed (1) A decrease in the survival of mouse intestinal crypt began 6h after the irradiation,and the lowest survival rate appeared on the fourth day.(2) The survival of mouse intestinal crypt of the abdominal irradiated mice increased 21.4% at 6h after intestinal RNA injection as compared with that of the irradiated control group.(3) The dose modifying factor (DMF) of normal mouse intestinal RNA in the promotion of the recovery of the duodenum, jejunum and ileum of mice after whde body irradiation 1.17, 1.12 and 1.10 respectively. The above results suggest that mouse intestinal RNA can raise not only the survival of jejunum crypt of the mice of the same strain after abdominal irradiation but also the survival of crypt of the duodenum, jejunum and ileum of the mouse after whole body irradiation, which may be observed 6h after the irradiation.关键词：Intestinal RNA;γ ray;Mouse;Survuval of mouse crypt
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发布时间：2023-04-07 - 摘要：The interaction of oxidized FAD radical with dGMP, dAMP and single—stranded DNA (ssDNA) was investigated in neutral aqueous solution using time—resolved 248 nm laser flash photolysis aimed at elucidation of the initial photosensitization mechanism. The characterized absorption spectra of transient species were observed. Moreover,direct observation of stabilized DNA guanyl radical has provided transient evidence for site—selective photosensitized damage of DNA at guanine moiety, which has simulated the major initial species produced by the direct effect of ionizing radiation or UV light on DNA.关键词：DNA;Flavin adenine dinucleotide (FAD);Laser flash photolysis;Guanyl radical;Site—selective damage
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发布时间：2023-04-07 - 摘要：To investigate G1 arrest and the expressions of relative proteins in EL-4 cells induced by ionizing radiation, flow cytometry (FCM) was used to analyze cell cycle through staining cells with propidium iodide (PI). And FCM was also employed to analyze protein expression of EL-4 cells stained wity monoclonal and polyclonal antibodise for their immunofluorescence. It was found that the number of EL-4 cells in G1 phase increased significantly 12—72h after X-irradiation with doses of 2.0Gy and 4.0Gy. The resuits also showed significant increases of p53 protein expression at 2h to 24h (p<0.05 —p<0.001), p21 protein expression at 2h to 48h (p<0.05—p<0.001), GADD45 protein expression at 2h to 48h (p<0.05 —p< 0.001),and MDM2 protein expression at 4h to 24h (p<0.05—p<0.001) after 4.0Gy X-irradiation. These results suggest that G1 arrest of EL-4 cells could be induced by ionizing radiation and the expression of p53, p21 and GADD45 proteins may play an important role in the mechanism.关键词：Ionizing radiation;G1 arrest;Protein expression
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发布时间：2023-04-07 - 摘要：To clone the new genes involved in the repair of radiation—damaged intestinal crypts of mice which were treated with the intestinal RNA of the mice of the same strain. As a test group, 45 mice which had been irradiated by γ rays were injected with intestinal RNA of mice of the same strain in 2h after irradiation and the specimens of the small intestine of these animals were collected at 6,12, 24h, 4d and 8d after irradiation respectively. The other 45 mice, as a control group, were treated with irradiation and physiological saline,and the specimens were collected as those in the test group. The genes which expressed more highly in the test group than in the control were cloned into T vectors after subtractive hybridization and LD—PCR and then sequenced. The sequences obtained were aligned through GeneBank for the new gene search. 90 clones were found associate with the repairing of radiation—damaged mouse intestinal crypts, which was confirmed by RNA dot blot assays. Among the 90 clones, 18 were accepted by GeneBank as new genes with the acceptance numbers AF240164—AF240181. Obtained ninety clones may be correlated closely with repairing of intestinal epithelium of the γ —irradiated mice by treatment with the intestinal RNA of mice of the same strain.关键词：Irradiation;Repair;Intestinal gland cell;Cloning
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发布时间：2023-04-07
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