最新刊期
期 3 ， 2008
- 摘要：To survey the variance of Gadd45 mRNA in different people’s blood exposured to ionizing radiation, which is necessary in evaluating the feasibility of Gadd45 as a radiation biodosimeter, 27 normal persons’ peripheral blood was irradiated with 60Co γ-rays in vitro. And its RNA was isolated from white cell. The relative real-time quantitative PCR by standard curve method was set up using β-actin as internal standards. With this method, Gadd45 mRNA expression change was observed after ionizing radiation. It has been found that in 0~2.5Gy range the relationship between the ratio of Gadd45 mRNA / β-actin and irradiation dose represents certain line correlation. A linear regression equation (y=0.216+0.258x, p<0.001, R2=0.650) has been obtained using statistics regression analysis method which can be used to estimate the biological doses involved in radiation accidents though the variance of the Gadd45 mRNA level among different people is marked.关键词：Ionizing radiation biodosimeter;Peripheral blood leucocyte;Gadd45;Fluorescence real-time quanti- tative polymerase chain reaction (PCR)
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发布时间：2023-03-30 - 摘要：Silk fabric samples were grafted with 2-hydroxypropyl acrylate monomer by ultraviolet rays, and a light-initiated graft copolymerization system without any additives or co-additives had been established. Experiments were performed to study effects of monomer concentration, irradiation time, pH value on the grafting rate. FT-IR and DSC characterizations of the grafted silk samples were carried out to study the property changes in the silk fabrics. With advantages of fairly high graft rate, simpler equipment and operation and free of additives, the method may be an effective technique to improve the properties of silk fabrics.关键词：Silk;2-hydroxypropyl acrylate;UV-irradiation;Graft copolymerization
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发布时间：2023-03-30 - 摘要：The effect of composition of PSIUA system on physical and mechanical properties of UV curing silicone (PSIUA) materials including water resistance, volume shrinkage, hardness, adhesion and chemical resistance, has been studied in this paper. The results show that reactive monomers with hydroxyl and ether bonding could increase water absorption of the PSIUA system. And the water absorption of the PSIUA system decreases with increment of crosslinking yields. The volume shrinkage of the PSIUA system decreases with increment of PSIUA concentration in the system and the volume shrinkage of investigated PSIUA systems is lower than 10%. Trifunctional monomer and epoxy acrylate with rigid structure and higher crosslinking yield could improve hardness of PSIUA system. Addition of the monomers with hydroxy and epoxy acrylate could enhance adhesion of PSIUA system. Glass transition temperature of PSIUA system has been determined to be 246.0℃.关键词：UV-curing;Silicone;Properties of material
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发布时间：2023-03-30 - 摘要：Polycarbosilane (PCS) precursor fibers were irradiated by γ-rays in air. The structure and the subsequent pyrolysis reaction of PCS fibers irradiated below gelling dose were investigated. Results show that a little of oxygen is imported to form the structures of Si-O-Si、Si-OH and C=O from Si-H and Si-CH3 of PCS in irradiation process. And gelatinized products formed from the Si-O-Si and Si-C-Si bridge structures obviously increase with the heat treatment temperature. It has been also found that the initial pyrolysis temperature of irradiated PCS fibers increases from 320℃ to 600℃, and the ceramic yields increase from 57.5% to about 83%. All the samples of PCS precursor fibers irradiated below gelling dos and under the condition with a little of oxygen can be pyrolyzed into SiC ceramic fibers with intact microstructure.关键词：Polycarbosilane precursor fibers;γ-rays irradiation;Bridge structures;Curing;Thermal cross-linking
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发布时间：2023-03-30 - 摘要：The irradiation-induced degradation of chloramphenicol by γ-rays in aqueous solution was studied and the radiolytical products were determined. The relationship among degradation rate, absorbed dose and initial concentration have been explored by comparing the position of maximum absorption peaks of chloramphenicol before and after irradiation using high performance liquid chromatography. The identification of radiolytical products has been conducted using liquid chromatography tandem mass spectrometry. It has been found that the relationship among C/C0, absorbed dose and initial concentration can be fit with index curve. After irradiation, more than 30 radiolytical products with stable absorption below 278nm could be determined. 8 major radiolytical products with [M-H]- 353, 337, 335(A), 335(B), 319, 289, 127, 166, which are detected in several different conditions, have been picked up. Their possible structures are deducted.关键词：γ-rays;Chloramphenicol;Radiation degradation
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发布时间：2023-03-30 - 摘要：Natural rubber (NR)can be precured by γ-rays irradiation. In this paper sensitizing efficiency of two polyfunctional unsaturated monomers (PFM), Trimethylopropane trimethylacrylate (TMPTMA) and Triallyl isocyanurated, on irradiation precuring of NR was studied. The effects of irradiation precuring were evaluated by the crosslinking degree (1/Mc) and Green strength of NR. The results show that TMPTMA is efficient to irradiation precuring of NR. However, the effects of TAIC is less efficient on irradiation precuring of NR at 0~100kGy. It has been found that the crosslinking degree and Green strength of NR/TMPTMA can be enhenced with the increment both of absorbed dose and TMPTMA content.关键词：Natural rubber (NR);γ-rays irradiation;Irradiation procuring;Polyfunctional unsaturated monomers (PFM);Green strength
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发布时间：2023-03-30 - 摘要：Hyperbranched aliphatic polyesters were synthesized in the molten state from 2,2-bis(hydroxymethyl) propionic acid and 2-ethyl-2-(hydroxymethyl)-1,3-propanedio(core molecule) by using p-Toluenesulfonic acid catalysis. The synthesis procedure was a pseudo-one-step reaction which stoichiometricamounts corresponding to each generation were added successively. The polyesters with hydroxyl groups as terminal groups were glassy solids at room temperature. The chemical structures and properties of these polymers were characterized by 13C NMR, FT-IR, GPC, DSC. One of the polymers was further modified by stearic acid and methacrylic acid to form a hyperbranched polymer terminated in stearic and methacrylic groups partially, which could be used as main resin in UV-curable powder coatings system.关键词：Hyperbranched polyester;Modification for terminal groups;UV-curable resin
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发布时间：2023-03-30 - 摘要：In this paper, the changes of telomerase activity in human liver cells after exposed to the heavy ion radiation were investigated. Irradiation was performed at the Heavy Ion Research Facility in Lanzhou (HIRFL). The hepatocellular cells HL-7702 and the hepatocellular carcinoma cells SMMC-7721used as model cell were exposed to 12C6+ irradiation at 0, 1, 2, 3 and 4Gy and formal irradiated cell was re-cultured for 72h and later irradiated cell was re-cultured for 24h and 72h respectively. PCR based on telomeric repeat amplification protocol (TRAP-PCR) method was used to determine the telomerase activity in SMMC-7721 and HL-7702, respectively. It has been found that the HL-7702 cells don’t express the telomerase activity at 0Gy, 1Gy and 4Gy while the cells exposed to 2Gy and 3Gy express the telomerase activity clearly (p<0.05). But when the SMMC-7721 cells are exposed to heavy ionizing radiation at 1~3Gy, the telomerase activity significantly increases in a dose and time dependent manner (p<0.05). From this experimental results it can be concluded that heavy ionizing radiation, as a high LET radiation, could induce changes of telomerase activity. It can also be indicated that telomerase participates in the repair process of DNA exposed by heavy ionizing radiation and 12C6+ in tumor therapy could kill tumor cells more efficiently than that by the other low LET rays.关键词：Telomerase;Heavy ion;SMMC-7721 cells;HL-7702 cells;PCR-telomeric repeat amplification protocol
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发布时间：2023-03-30 - 摘要：In order to cut down the chemical oxygen demand of Chlorine-Bleaching Effluent the activated carbon was used to treat the west water under microwave radiation. With activated carbon mass fraction 1.0g, microwave radiation time 8min, microwave power 800W, the CODCr decrease from 1176mg/L to 50mg·L-1, the removal rate of CODCr is above 95%. The results show that the chemical oxygen demand of Chlorine-Bleaching Effluent can be reduced effectively and the related mechanism has been discussed.关键词：Microwave irradiation;Wheat straw pulp Chlorine-Bleaching Effluent;Activated carbon
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发布时间：2023-03-30 - 摘要：The mutagenesis effects on the yield of amylase have been investigated with Bacillus subtilis irradiated by γ-rays and fast neutrons in once or twice irradiation at various dose rates and total irradiation doses. Several parameters such as flat transparent circle, colony diameter, transparent circle diameter and the ratio of flat transparent circle to colony diameter (HC) are used to estimate the radiation mutation of Bacillus subtilis. A series of results has been obtained as (1) Irradiation both with neutrons and γ-rays could make Bacillus subtilis mutationed to produce high-yield amylase effectively. (2) The average colony diameter of Bacillus subtilis irradiated by γ-rays or fast neutrons is smaller than that of control group at various total doses and dose rates. And their colony diameter becomes smaller slightly with the increment of γ-rays irradiation dose. (3) After the second neutrons irradiation, the values of average colony diameter, the biggest colony diameter, average transparent circle diameter and the biggest transparent circle diameter of all mutationed Bacillus subtilis exceed that of original strains greatly. (4) Three kinds of mutationed Bacillus subtilis strains with high-yield amylase have been screened out, in which two strains can produce high-yield amylase steadily after 15 times breeding. Their biggest colony diameter, the biggest transparent circle diameter and the biggest HC value are up to 8.32 mm, 22.38 mm and 5.39 respectively.关键词：Neutrons irradiation;γ-rays;Mutation breeding;Amylase
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发布时间：2023-03-30 - 摘要：In this paper investigating inhibitory effect and radiation sensitization of recombinant adenovirus encoding human p53 tumor suppressor gene (rAd-p53) on human lymphoma cell lines has been performed by MTT, Laser confocal scanning microscope (LCSM) and flow cytometry. The results show that the inhibitory effect of rAd-p53 on human lymphoma cell lines is not obvious enough even though it is both dose-dependent and time-dependent. It has been found that cell inhibition and apoptosis ratios increases and cell cycle and morphology features changes apparently in radiation therapy and combined therapy. But there is no obvious difference in them. The results indicate that the transfection ratio of rAd-p53 on human lymphoma cell lines needs much improvement in order to strengthen the sensitivity of cell to radiation.关键词：Gene therapy;rAd-p53;Radiation therapy;Human lymphoma cells line
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发布时间：2023-03-30 - 摘要：This study is try to investigate the positive ratio of the mitochondrial DNA (mtDNA) 4934bp deletion in normal human population and if this deletion could be induced by ionizing radiation. 109 normal human peripheral blood samples were collected and analyzed for the mtDNA 4934bp spontaneous deletion by PCR. 3 samples of human normal peripheral blood with mtDNA 4934bp spontaneous deletion were exposed to 0, 2 and 6Gy 60Co γ-rays in vitro, and the analysis of the mtDNA 4934bp deletion was made after exposure. Finally, semi-quantification PCR was used to analyze the 4934bp deletion level after 0, 2 and 6Gy irradiation with normal peripheral blood samples. The results show that 45/109 or 41% of normal human peripheral blood samples have spontaneous 4934bp deletion, and the BLAST results are proved that the 4934bp deletion locates in nt8435-nt13368 on heavy strand. The spontaneous deletion rate increases with the age (p<0.01). The 4934bp deletion is detected in peripheral blood samples before and after irradiation and the 4934bp deletion level is 23, 25 and 27 respectively at the irradiation dose of 0, 2 and 6Gy. These observations suggests that it would be a normal case of spontaneous 4934bp deletion in normal human peripheral blood, and the 4934bp deletion level could be enhanced along with the dose of ionizing radiation.关键词：60Co γ-rays;Human peripheral blood;Mitochondrial DNA deletion;4934bp
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发布时间：2023-03-30
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