最新刊期
      期 1 ， 2003
      • LUO Zhengming
        Vol. 21, Issue 1, Pages: 1-17(2003)
        摘要：The paper gives a review on progresses in the past four decades in bipartition model studies. Its basic ideas and concepts, main mathematical formulae and numerical methods, and its relevant applications are described. The model has been extended from a transport theory for electrons of medium energy range to a unified and accurate transport theory of charged particles, covering ion transport, atomic cascade collision, particle emissions in surface sputtering, and penetration of electrons of radiation therapy energy range. The 15 figures give an extensive comparison between the results given by using the bipartition model and the data taken from other theories and experimental measurements, which shows that the bipartition model is an accurate, powerful and unified transport theory of charged particles. Problems remaining to be solved with the bipartition model are discussed in the paper.  
        关键词：Transport for charged particles;Bipartition model;Partition condition   
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        发布时间：2023-03-30
      • SUN Jiazhen
        Vol. 21, Issue 1, Pages: 18-24(2003)
        摘要：Flexibility of polymer chains is an important factor to effects of radiation crosslinking of the polymer. Polymers with flexible chains are easier to be crosslinked, with lower dose of gelation, than polymers with more rigid chains. And it is known that most polymers with abnormal rigidity can be radiation-crosslinked only at high temperatures when the molecular chains get enough mobility. The flexibility of polymer chains also influences the relationship between degree of degradation and radiation dose. A chain flexibility factor β has been introduced to modify the Charlesby-Pinner equation of sol-fraction and radiation dose. The new relationship equation applies to a wider range of polymers in radiation crosslinking. Studies also show that for flexible polymers with lower Tg and molecular internal rotating factor, mechanism of radiation crosslinking is mainly in H type, whereas for rigid polymers with higher Tg and molecular internal rotating factor, mechanism of radiation crosslinking is mainly in T type.  
        关键词：Radiation crosslinking;Flexible polymer;Rigid polymer   
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        发布时间：2023-03-30
      • RAO Yalan,CHEN Xiaohua,MAO Bingzhi
        Vol. 21, Issue 1, Pages: 25-28(2003)
        摘要：The paper summarizes the complexity of gene expression induced by radiation, and describes applications of DNA microarray in research of radiation-induced genes in recent years. Progresses in studies on radiation-induced genes may provide a new direction for basic research of diagnosis and therapy of radiation injure.  
        关键词：DNA microarray;Radiation-induced genes;Radiation injure   
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        发布时间：2023-03-30
      • LIANG Xiaofeng,HU Tianxi,FAN Xiaobing
        Vol. 21, Issue 1, Pages: 40-44(2003)
        摘要：We established a chemiluminescent system for determination of lipid peroxidation and screening antioxidants. The lipid containing unsaturated fatly acids was injected into a glass tube. Luminol solution and the deionized water were added into it too. The glass tube was put into a preincubation box to incubate it for 0.5h at 37℃. AAPH solution was injected into the tube for immediate measurement in a biochimiluminometer at 38—39℃. The pulses / 6s (CP6s) were determined with T-2 program. Chemiluminescent dynamic and lipid peroxidation changes were observed continuously. Once the CL intensity of lipid peroxidation got peak, the antioxidant which has different concentration was added immediately in situ. A certain CL intensity (CP6s) was chosen as evaluation index to compare the activity of antioxidants. A luminol chemiluminescent system for determination of lipid peroxidation has been made. It was found that Vit.C, teapolyphenol, and glutathione have effects on scavenging lipid free radicals. The new method is quick, sensitive, and simple for determination of lipid peroxidation and screening antioxidants.  
        关键词：Chemiluminescence;Lipid peroxidation;Antioxidants   
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        发布时间：2023-03-30
      • JIAN Le,QIAN Suping,YAO Side,JIANG Huai
        Vol. 21, Issue 1, Pages: 45-48(2003)
        摘要：Pulse radiolysis technique was used to probe the generation of radical cations from carbon disulfide, and characteristic absorbance spectra of the radical cations were obtained by time-resolved transient absorbance spectrum method. The injury mechanism of the bio-molecular targets by the free radicals and relative constants of reaction kinetics were studied. Results showed that the radical cations could react with DNA, dGMP, tyrosine and tryptophan and form new products, which may play an important role in oxidative injury on bio-molecules by carbon disulfide.  
        关键词：Carbon disulfide;Radical cations;dGMP;DNA;Tyrosine;Tryptophan   
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        发布时间：2023-03-30
      • XIE Hongfeng,DONG Lisong,SUN Jiazhen
        Vol. 21, Issue 1, Pages: 49-53(2003)
        摘要：Radiation Crosslinking can improve the electrical stability and eliminate the NTC effect of carbon black filled thermolplastic composites. The paper gives a review on electrical mechanisms of the PTC effect, advantages of radiation crosslinking, radiation crosslinking influence on the PTC and NTC effect, and new applications of radiation crosslinking on conductive composites.  
        关键词：Carbon black;Radiation crosslinking;Conductive composites;PTC/NTC effect   
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        发布时间：2023-03-30
      • XIN Renxuan,LIANG Junfu,SONG Chongli
        Vol. 21, Issue 1, Pages: 54-58(2003)
        摘要：Emulsion characteristics and demulsification performance of trialkylphosphine oxide(TRPO), which is a useful extractant for treatment of high active waste, were studied by spectrometric method. Results showed that demulsification of organic phase equalized with nitrate acid became faster than with pure water. The emulsion characteristics were compared with TRPO of various sources. The effect of γ-irradiation was remarkable for emulsion formation of TRPO. The emulsion of irradiated TBP(Tributyl phosphate) and TRPO were compared. Demulsification of TRPO was slower than irradiated TBP. When using a 5%Na2CO3 as solvent cleanup reagent, the phase separation of irradiated TBP was faster than irradiated TRPO, but demulsification of aqueous phase was slower for irradiated TBP.  
        关键词：γ-Irradiation;Solvent extraction;Emulsion;Trialkylphosphine oxide(TRPO);Tributyl phosphate   
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        发布时间：2023-03-30
      • XIE Hongfeng,DONG Lisong,SUN Jiazhen
        Vol. 21, Issue 1, Pages: 59-62(2003)
        摘要：Reproducibility of electrical conductivity of low density polyethylene (LDPE)/carbon black (CB) during the heating/cooling recycling was studied. The melting behavior and volume expansion behavior of the composites were investigated with differential scanning calorimetry (DSC) and press-volume-temperature (PVT) analyzer, respectively. It is found that reproducibility of PTC effect of the LDPE/CB composites was effectively increased after radiation crosslinking. PTC intensity of the gel of the composites decreased greatly as compared with the irradiated composites. This suggests that the volume expansion of the sol at the melting point of the polyethylene played an important role in the PTC effect.  
        关键词：Carbon black;Radiation crosslinking;Electrical conductive composites;Positive temperature coefficient (PTC) effect   
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        发布时间：2023-03-30
      • GAO Linfeng,WANG Hongfu,XU Peikang,XU Aihong,ZHU Feipeng
        Vol. 21, Issue 1, Pages: 63-68(2003)
        摘要：The work was to observe the effects of γ-rays radiation of rat kidneys on rat bone metabolism. Ten male SD rats aged 6 months were irradiated at their kidneys with 15Gy 137Cs γ-rays( 0.91 Gy/min) and were raised for 3 months after the radiation. On collecting 24h urine of rats they were sacrificed for serum, kidney, spine , femur and tibia exams. Results show that theγ-ray irradiation could induce the pathological injuries of renal glomeruli, tubules and mesenchyme. Comparing to the control group, significant chages were found in the irradiated group in terms of their blood urea, nitrogen creatinine, urinal β-2 microglobulin, serum Ca and P, urine Ca and P, activity of serum alkaline phosphatase, 1,25(OH)2 D3, serum PTH, urine PYD/creatinine, bone mineral density(BMD) of lumbar vertebras, mineral mass of No.4 lumbar vertebra, BMD, dehydrated weight and ash weight of right femur. Marked changes were also found in bone trabecula volum, average bone trabecula thick and the ratio of nodes/points, and rate of mineralizatal deposition. It was concluded that renal dysfunction and metabolic bone disease might occur with the character of accelerated bone turnover and decreased bone mass.  
        关键词：Radiation;Kidney;Bone metabolism   
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        发布时间：2023-03-30
      • LU Ying,YANG Zhihua,CAO Zhenshan,FAN Feiyue,ZHU Maoxiang,Tom K Hei
        Vol. 21, Issue 1, Pages: 69-72(2003)
        摘要：Human-hamster hybrid cells (AL cells) were used for observing survival bystander effect induced by alpha-particle irradiation through both models: inserting a grid between the radiation source and the sample to irradiate 15% of the cells, and using the medium of the irradiated cells to culture the unirradiated cells. Free radical scavenger DMSO and intercellular communication inhibitor lindane were selected to investigate the potential mechanism of alpha-particle irradiation-induced bystander effect. Results show that the survival fraction of unirradiated cells shielded by the grid or cultured with the medium of the irradiated cells were much lower than expected or normal level. However, DMSO and lindane could obviously increase cell survival fraction. These indicate that alpha-particle irradiation could induce bystander effect, and reactive oxygen species, and intercellular communication might play an important role in the process.  
        关键词：α-particle irradiation;Cell survival;Bystander effect;Reactive oxygen species;Intercellular communication   
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        发布时间：2023-03-30
      • GU Guixiong,ZHU Shoupeng,WANG Liuyi,YANG Shuqin,ZHU Lingli
        Vol. 21, Issue 1, Pages: 73-76(2003)
        摘要：This is a study on injurious effects of cellular spermidine to PC12 cells irradiated by enriched uranium. PC12 cells were cultured in DMEM/F12 medium with enriched uranium, and the exposure doses were calculated. The contents of free spermidine PC12 cells were examined with Densly-cholrade reaction and thin-layer chromatography. Viability of the cells treated with enriched uranium reduced rapidly and DNA strand break increased significantly with increasing time of the irradiation. Autoradiographic tracks showed that the radionuclide located in the nucleus predominantly. The content of free spermidine in PC12 cells could markedly decrease as the irradiation time increased. The results suggested that PC12 cells exposured to enriched uranium were apoptotic and the free spermidne in cells might play some role in this process.  
        关键词：Spermidine;Enriched uranium;PC12 cells;Apoptosis   
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        发布时间：2023-03-30
      • ZHANG Junning,HONG Chengjiao,ZHU Shoupeng
        Vol. 21, Issue 1, Pages: 77-80(2003)
        摘要：In this paper, apoptosis and expressions of bcl-2 and bax protein in K562 cells exposed to different doses of strontium-89 were studied. Six hours after the irradiation, characteristics of apoptosis and necrosis appeared in the K562 cells. The apoptosis and necrosis in the cells irradiated for 6, 9, 12, 24 and 48h were significantly higher than the control. The expression of bcl-2 decreased after the irradiation, whereas bax had no obvious changes. The results suggested that the apoptosis of K562 cells induced by exposure to 89Sr might be regulated by reduced expression of bcl-2 and bcl-2/bax ratio.  
        关键词：Strontium-89;K562 cells;Apoptosis;Bcl-2;Bax   
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        发布时间：2023-03-30

        研究论文

      • BAO Huaying,S. Navaratnam,B. J. Parsons,G. O. Phillips
        Vol. 21, Issue 1, Pages: 29-34(2003)
        摘要：The one-electron oxidation of phenanthrenequinone (PhQ) in aqueous solutions was investigated by pulse radiolysis using hydroxyl radical and sulphate radical as oxidants. Spectral and kinetic properties of the transients formed due to the reaction of PhQ with the oxidants were obtained. The reaction of hydroxyl radical with PhQ results in an initial species with an absorption spectrum centered at 370nm and a weak broad band in the long wavelength regions at neutral pH. The bimolecular rate constant for the formation of initial species was determined to be (1.5±0.2)×1010dm3 •mol-1 •s-1. The absorption in the short wavelength region decays with a concomitant increase in the longer wavelength region resulting in a subsequent species with absorption maximum at 400nm and a broad band centered at 500nm. The absorption in visible region increases with increasing pH. Similar transient absorption was obtained at pH 9.9. At pH 4.0, the initial spectrum also shows absorption maximum at 370nm. However, the subsequent absorption spectrum shows a maximum at a shorter wavelength than those found at pHs 7.1 and 9.9. The absorption increase in visible region was not seen at low pH. The transient spectrum obtained at neutral pH by the reaction of sulphate radical with PhQ are similar to the subsequent spectra for the reaction of hydroxyl radical with PhQ showing two bands centered at 400 nm and 500 nm. The bimolecular rate constant was estimated at (4.0±0.6)×109dm3 •mol-1 •s-1. On the basis of spectral similarity and kinetic analysis, a possible mechanism for the oxidation of PhQ by both hydroxyl radical and sulphate radical is given.  
        关键词：Pulse radiolysis;One-electron oxidation;9,10-Phenanthrenquinone   
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        发布时间：2023-03-30
      • EKOKO BAKAMBO GRACIEN,XIN Lihui,ZHOU Ruimin
        Vol. 21, Issue 1, Pages: 35-39(2003)
        摘要：γ-irradiation technique was used with success to prepare nanocrystalline zinc sulfide at room temperature and ambient pressure, without adding any kind of catalysts. Sodium thiosulfate and carbon disulfide were used as sulfur sources in water and absolute alcohol systems, respectively. Structure and morphology of the nanocrystallines ZnS have been characterized by XRD and TEM analysis. The product has a cubic structure and, morphologically, is in spherical shapes of 20 to 50 nanometers in size. Probable mechanisms of the nanocrystalline formation in different systems are proposed in accord with the experiment.  
        关键词：ZnS nanocrystalline;Water system;Alcohol system;γ-irradiation   
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        发布时间：2023-03-30
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