最新刊期
期 2 ， 2008
- 摘要：Non-irradiated bystander human glioblastoma T98G cells were co-cultured (CC) with irradiated cells or treated with conditioned medium (CM) from irradiated cells under hypoxic condition, then micronucleus (MN) of both irradiated cells and bystander cells were measured for the investigation of radiation induced bystander effect and its mechanism. It has been found that the MN yield (YMN) of non-irradiated bystander T98G cells is obviously enhanced after the cell co-culture, or CM treatment, but this increment is diminished by free radical scavenger, dimethyl sulfoxide (DMSO). When hypoxic or normoxic T98G cells are treated with CM obtained from irradiated cells under either hypoxic or normoxic condition, the biggest bystander response has been observed in the group of hypoxic bystander cells treated with CM from irradiated normoxic cells. However, all of these increments of bystander YMN could be eliminated by aminoguanidine, an iNOS inhibitor. Therefore, under hypoxic condition, free radicals, especially reactive oxygen species and nitric oxide, are involved in the bystander response induced by irradiated T98G cells.关键词：Hypoxia;Radiation induced bystander effect;Micronuclei;Reactive oxygen species;NO
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发布时间：2023-03-30 - 摘要：EL-4 lymphoma cells were irradiated with the inductive doses (D1: 25 ~ 200 mGy, dose rate: 12.5mGy/min) and the challenging dose (D2: 0.5 ~ 3.0 Gy, dose rate: 287 mGy/min), and the time interval between D1 and D2 was 6 h. The percentage of cell apoptosis and the expressive levels of cell apoptosis-associated gene proteins were measured with flow cytometry. The percentages of cell apoptosis in the D1 + D2 group with 25 ~ 100 mGy (D1) and 1.5 Gy (D2) or 75 mGy (D1) and 25 ~ 200 mGy (D2) were significantly lower than those in the D2 group. As compared with the D2 group, the positive percentage of cell Bcl-2 protein expression increased somewhat, and Bax decreased significantly, meanwhile the ratio of Bcl-2/Bax increased significantly and p53 decreased somewhat in D1 + D2 group with 25 ~ 100 mGy (D1) and 1.5 Gy (D2). The adaptive response of EL-4 lymphoma cell apoptosis could be induced by pre-irradiation with 25 ~ 100 mGy. Meantime, the expressive levels of cell apoptosis-associated gene Bcl-2, Bax and p53 proteins could change accordingly with cell apoptosis. These gene protein changes may play an important role in the mechanism of the adaptive response.关键词：Ionizing radiation;Lymphoma cell;Cell apoptosis;Apoptotic gene;Anti-apoptotic gene;Adaptive response
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发布时间：2023-03-30 - 摘要：In this study the effects of cell reproductive death and DNA damage of Lewis lung carcinoma cells exposed to 89.63 MeV/u carbon ion beam were compared with that exposed to 6 MeV X-rays irradiations in order to explore the feasibility and advantage of tumor therapy by use of heavy ions beam. Results showed that the relative biological effectiveness (RBE) value of the carbon ion beams at 10% survival level was estimated up to 1.77. There are linear effects in the dose response curves both of "Tail DNA (%)" (TD) and "Olive tail moment" (OTM) obtained with comet assay for the X-rays irradiation. However, the carbon ion beams revealed biphasic dose responses including linear and exponential terms. The dose responses for the carbon ion beams had a saturated effect beyond about 8Gy. There was an inverse correlation that the high linear energy transfer (LET) carbon ion beams produced a low survival fraction at 2Gy (SF2) and a high initial Olive tail moment at 2 Gy (OTM2) compared with X-rays irradiation. In conclusion, carbon ion beams with high LET values might produce more severe cell reproductive death and DNA damage in Lewis lung carcinoma cell in comparison with X-rays, which could make the tumor therapy more effective.关键词：DNA damage;Carbon ion beam;X-rays;Comet assay
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发布时间：2023-03-30 - 摘要：The study of heavy ion beams as a new irradiation resource on seeds of linseed (Linum usitatissmum L.) was reported. After irradiated by 12C 6+ heavy ions (with irradiation dose: 6×108 cm-2, 1.8×109 cm-2 and 3.6×109 cm-2 respectively), the biological characters, agricultural traits, pollens and polymorphic DNA of sample was studied in Linum usitatissmum L.. The results showed that 6×108 cm-2 of 12C 6+ could promote the linseed germination rate, plant height and pollen viability. The 1000-seed weight and the oil content of seed irradiated by 12C6+ heavy ions was increased with augment of irradiation dose respectively. It has been found that 3.6×109 cm-2 is the most effective dose for increment both of seed weight and oil content with 16.5% and 19.9%, respectively. Cytological observation reveals that the highest dose (3.6×109 cm-2) can also induce alteration of pollen shape of linseed. Furthermore, RAPD(Randomly amplified polymorphic DNAs) analysis shows that 99 DNA fragments are amplificated by 14 primers and the polymorphic ratio is 52.5%.关键词：12C6+ heavy ions;Linum usitatissmum L.;Biological effect;RAPD(Randomly amplified poly- morphic DNAs) analysis
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发布时间：2023-03-30 - 摘要：Lentinula edodes were implanted with various nitrogen ions implantation dosage but the same energy in this study. The variations of growth rate of mycelium, mycelial biomass and the contents of lentinan(LNT) under various nitrogen ions implantation dosage were investigated. Three curves of implantation all take a "saddle shape" with increasing N+ ion implanted doses. The growth rate of mycelium is high under low dosage of N+ implantation, but with the increment of dosage, the growth rate shows downtrend then began rising when the dosage reaching 1.5×1016 cm-2. The mycelia biomass and the contents of LNT rise firstly and then fall with the increment of dosage, and they both reach maximum at the dosage of 4×1015 cm-2. Some fluctuation exists in the process, so they both reach another peak at the dosage of 1.5×1016 cm-2. During the liquid culture of Lentinula edodes, the variation of mycelial biomass, gross weight of shake-flask, pH and the contents of lentinan(LNT) has been studied. The consistency between the variation of mycelia biomass and gross weight of flask during the liquid culture has also been confirmed. This result can be applied to the study on fermentation before and mutation. Thus a conclusion may be drawn that it is an effective way of mutation breeding by N+ ion implantation.关键词：Lentinula edodes;Ion implantation;Mutation breeding;Fermentation;Lentinan(LNT)
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发布时间：2023-03-30 - 摘要：Blakeslea trispora(−) was used as experimental model, and the effects of N+ ions implantation on the activities of their catalase (CAT), peroxidase (POD), total antioxidase (T-AOC), superoxide dismutase (SOD) and the function of scavenging free-radicals (O2–• and ·OH ) were investigated. The results show that CAT activities are lower than that of control groups. With the increasing of N+ ion implantation POD, SOD activities and the function of scavenging O2–• and ·OH decrease at the beginning, and increase lately. At the dose of 6.0×1015 cm-2 T-AOC activity is the lowest and at the dose of 1.2×1015 cm-2 its activity becomes the highest. It can be considered that the changes of T-AOC, POD, SOD CAT activities and cell scavenging O2–• and ·OH activities have some relationship with the "saddle shape" survival rate curve in the ion implantation breeding.关键词：Blakeslea trispora;N+ ion implantation;Antioxidase;β-carotene
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发布时间：2023-03-30 - 摘要：Effects of 60Co γ-rays irradiation on protein, amylase, total amylum, amylum viscosity chart, gel consistancy of rice (glutinous rice, japonica rice and early indica rice) were studied. The results indicate that after the irradiation treatment by the dosage of 0.5~7 kGy irradition, the contents of amylum, gel consistency obviously decrease with increment of the irradiation dose. And the peak paste, hot paste and cool paste of amylum viscosity chart also decrease with increment of the irradiation dose. The results show that the irradiation dose for eliminating pests of rice should be controlled under 3 kGy.关键词：Irradiation;Rice;Property
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发布时间：2023-03-30 - 摘要：The structure of G-quadruplexes formed in different cation solutions and the corresponding mode of interaction with AQ derivatives have been studied using Ultraviolet and visible spectrophotometry(UV-Vis), Circular dichroism(CD) and Polyacrylamide gel electrophoresis(PAGE). The results reveal that mono- and tetracation- substituted anthraquinone derivatives, AQS2 and 2,7-AQS2, bind to G-quadruplexes with different mode resulting in dissimilar photodamage mechanisms. The former appears to bind to G-quadruplexes through intercalation while the latter associates with a groove.关键词：G-quadruplex;AQS2;2;7-AQS2;Circular dichroism;Polyacrylamide gel electrophoresis(PAGE)
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发布时间：2023-03-30 - 摘要：A hydrogel copolymer of N-isopropylacrylamide/β-cyclodextrin was prepared by radiation copolymerization method. β-cyclodextrin (β-CD) based monomer (MAH-β-CD) containing vinyl and carboxyl functional groups was synthesized by modification of β-CD with maleic anhydride (MAH). And then the mixture aqueous solution of NIPAAm and MAH-β-CD was irradiated by electron beams with BIS as cross-linking agent for sample of poly (NIPAAm-co-MAH-β-CD) hydrogel. The effects of temperature, pH and ionic strength on swelling ratio of the hydrogel were determined meanwhile the effect of irradiation absorbed doses on its swelling and deswelling properties was also described. Experimental results show that the copolymer hydrogel possesses temperature, pH and ionic strength sensitive functions.关键词：β-Cyclodextri;N-isopropylacrylamide;Radiation polymerization;Hydrogel;Temperature-sensitivity;pH-sensitivity
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发布时间：2023-03-30 - 摘要：Au/Fe3O4 composites were formed by irradiating the aqueous solution of HAuCl4 containing poly(vinyl alcohol) (PVA) with UV light at a wavelength λ=254 nm in the presence of Fe3O4 nanoparticles. The properties of the as-prepared composites were characterized by means of ultraviolet spectra (UV-vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. XRD pattern confirmed the face-centered cubic phase of Au nanoparticles in the composites. The surface plasmon resonance band of the sample was rather narrow, which indicated a relatively narrow size distribution of Au nanoparticles. TEM revealed that Au/Fe3O4 composites with a size range of 70~230 nm had cluster structure, composed of a number of Au and Fe3O4 nanoparticles. Furthermore, it turned out that PVA was necessary for constructing the composites. A possible mechanism was proposed for the formation of Au/Fe3O4 composites.关键词：Au-contained magnetic composite;UV irradiation;Cluster structure;Poly(vinyl alcohol)
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发布时间：2023-03-30 - 摘要：A hydroxyl methacrylate monomer, o-hydroxycyclohexyl methacrylate (HCMA), was synthesized by opening ring reaction of cyclohexene oxide with methacrylic acid. Real time infrared spectroscopy (RTIR) was used to study the effect of molecule structure, light intensity, various photo-initiator and initiator concentration on photo-polymerization kinetics. HCMA and HEMA as comonomers were utilized to prepare hydrogel by photo-polymerization method. The mechanical strength of poly (hydroxyethyl methacrylate) (HEMA) and poly (HEMA-co-HCMA) hydrogel was conducted by dynamic mechanical analysis (DMA). The results demonstrated that increasing of light intensity and photo-initiator concentration escalate final double bond conversion. And the storage module and loss module of poly (HEMA-co-HCMA) hydrogel were higher than those of poly (HEMA) hydrogel.关键词：o-Hydroxycyclohexyl methacrylate;Photopolymerization;Kinetics;Hydrogel
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发布时间：2023-03-30 -
Radiation protection of waterlogged archaeological catalpa wood uncovered from Changtaiguan Xingyang
摘要：Waterlogged archaeological catalpa wood uncovered from Changtaiguan was tentatively treated by gradient dehydration of ethanol concentration, replacement of PEG200DMA gradually, and 60Co γ-rays radiation curing with absorbed dose 30.72 kGy at dose rate 90.35 Gy/min. It can be found that the color and appearance of reinforced archaeological wood with clear texture looks like original one. There is no cracking, no warping, and no glare on the wood surface. The Compression strength of reinforced ancient wood (33.06 MPa) is close to that of modern Catalpa wood. The maximum linear shrinkage of reinforced ancient wood is 1.05% in grain direction, 4.10% in radial direction, and 4.32% in tangential direction respectively compared with that of original sample. The linear shrinkage under the condition of 180 days storage in the ambient temperature and humidity is 0.076% in grain direction, 1.17% in radial direction, and 1.86% in tangential direction respectively. The linear shrinkage under the condition of 90 days storage in the temperature (25±2) ℃ and relative humidity (5±2)% is 0.066% in grain direction, 0.115% in radial direction, and 0.279% in tangential direction respectively. The linear swelling ratio after 90 days storage in the temperature (25±2) ℃ and relative humidity (98±2)% is 1.79% in grain direction, 2.42% in radial direction, and 2.61% in tangential direction respectively. It is confirmed by microstructure study that capillaries in residual wood has been filled with polymers, so that the wood mechanical strength and the shape stability is improved respectively.关键词：Waterlogged catalpa wood;Radiation curing;Compression strength parallel to the grain;Shape stability- 2
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发布时间：2023-03-30 - 摘要：To investigate the radioprotective effect of vitamin D against irradiation injury, the mice exposed to 60Co γ-rays at 6 Gy was treated with preparation of vitamin D(Alfacalcidol Soft Capsules). Cell cycle and apoptosis was analyzed by flow cytometry (FCM) following staining of cells with propidium iodide (PI). Peripheral blood cell counts were analyzed by autoanalyzer. It has been found that vitamin D significantly increases white blood cell (WBC) counts, decreases bone marrow PEC micronucleus rate. FCM analysis shows that compared with damaged group,G2 and S phases of bone marrow cells in vitamin D protection group increases significantly at 24 h after whole body irradiation, whereas G1 phase cells decrease at the same times. So vitamin D might be a new radioprotection agent and it should be deserved further study.关键词：Vitamin D;Radiation injury
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发布时间：2023-03-30 - 摘要：Intensity-modulated radiation therapy(IMRT) has been shown clinically to increase skin doses for some patients and to decrease skin doses for other patients. A set of IMRT plans for hypothetic targets in a solid-water phantom were designed to investigate the reasons. The results showed that the relative distance between tumor and surface was an important parameter which would affect surface dose strongly. The smaller distance would lead to the more monitor units (MUs), the higher dose at surface and the more probability for severe skin toxicity reaction.关键词：Intensity-modulated radiation therapy;Tumor position;Surface dose;Skin toxicity
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发布时间：2023-03-30
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