最新刊期
期 2 ， 2018
- 摘要：Silver nanodendrites of fine fractal structure were prepared under γ-ray liquid-phase irradiation with polyvinyl alcohol (PVA) as stabilizer. The morphology of the structure was characterized by Transmission electron microscope, High-resolution transmission electron microscope, Selective electron diffraction, and X-ray diffraction. The synthesis conditions and growth mechanism of the silver nanodendrites were studied. The results showed that PVA concentration was a key factor influencing the formation of the silver nanodendrites. In a reaction system with concentration of AgNO3, isopropanol at 0.02 mol/L and 1.0 mol/L, respectively, and absorbed dose of 75 kGy, the suitable concentration of PVA was between 2.5% and 5.0%. The silver nanoparticle concentration was another major factor affecting the formation of the silver nanodendrites. A suitable concentration of silver nanoparticles could be obtained with the concentration of silver nitrate at 0.02 mol/L and the absorbed dose between 30 kGy and 75 kGy. As a free radical scavenger, isopropanol affected the growth of the silver nanodendrites by interacting with PVA. The self-assembly growth mechanism of the silver nanodendrites could be described in three steps. Firstly, silver ions aggregated, nucleated, and grew to form polyhedral near-spherical primary particles. Secondly, the primary particles aggregated to form secondary particles such as twins and snowflake-like grains. Finally, the secondary particles aggregated with the primary particles to form silver nanodendrites.关键词：Silver nanodendrite;Irradiation reduction;Growth mechanism
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发布时间：2021-12-10 - 摘要：Polymerization was performed in a homogenous phase using N-methylpyrrolidone as the solvent. Pristine polyethersulfone (PES) and PES-grafted poly(N-vinylpyrrolidone) (PES-g-PVP) with different degrees of grafting (DGs) were then cast into membranes via phase inversion methodology. Crucial parameters affecting the graft copolymerization, such as the monomer concentration and absorbed dose, were studied. The results showed that increasing the monomer concentration and absorbed dose both served to improve the DG of the copolymer for monomer concentrations and absorbed dose less than 12% and 35 kGy, respectively. The presence of grafted chains was confirmed by Fourier-transform infrared spectroscopy. Scanning electron microscopy images showed that unlike the pristine PES membrane, the modified PES-g-PVP membrane possessed a "sponge-like" cross section. The contact angle of the PES-g-PVP membranes with a DG of 8.42% was lower than that of the pristine PES membrane by 12.1%, which indicated an improvement of the hydrophilic property of the membrane after grafting PVP onto PES molecular chains. The water flux of the PES-g-PVP membrane with a DG of 8.42% increased by a factor of approximately 4.9 compared with that of the pristine PES membrane, while its bovine serum albumin rejection rate was greater than 90%, indicating the improved antifouling properties of grafted PES-g-PVP membranes.关键词：Poly (N-vinyl-pyrrolidone);Polyethersulfone;Ultrafiltration membrane;Simultaneous irradiation in homogenous phase
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发布时间：2021-12-10
RADIATION CHEMISTRY
- 摘要：To explore the effects of fast neutron irradiation on seed germination and seedling growth of maize, some ZD958 and W9086 maize dry seeds were irradiated by fast neutron to absorbed doses of 0.98, 1.26, 1.51, 1.97, 2.48, and 3.37 Gy. When the absorbed dose was 3.37 Gy, the relative germination vigor of W9086 was 42.4%, and the germination vigor of ZD958 was 61.6%; the germination rate of W9086 was 61.6%, the germination rate of ZD958 was 73.7%; the shoot length of W9086 was 2.7 cm, the shoot length of ZD958 was 4.0 cm; the root length of W9086 was 4.9 cm, the root length of ZD958 was 4.9 cm; the root number of W9086 was 3.0, the root number of ZD958 was 3.7. All were lower than those of control group. These results showed that, with the increasing absorbed doses, the germination potential, germination rate, bud length, root length, and root number of plants in M1 generation were lower, compared with the control group. And the inhibiting effect was more obvious in W9086, indicating that the sensitivity of different corn cultivars to fast neutron irradiation was different.关键词：Maize;Fast neutron irradiation;Seed germination;Seedling growth
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发布时间：2021-12-10
RADIATION TECHNOLOGY APPLICATION
- 摘要：This study was to estimate the radiation field distribution and maximum storage capacity of a certain university's storehouse of radioactive sources without on-site detection, to provide optimized suggestions for radiation protection. The radiation field of the university's storehouse was simulated using Monte Carlo N particle transport code (MCNP) simulations, and compared with experimental values to verify the reliability of the simulation. The results revealed a difference of approximately 10% between the MCNP-simulated and experimentally measured values. Thus, our simulations were observed to provide relatively accurate estimations of the radiation field distribution and maximum storage capacities. The advantage of using MCNP simulations to estimate the radiation field in storehouses of radioactive sources and their surroundings lies in the fact that they enable one to effectively obtain the dose distribution at any point without entering the radiation field. The protective measures taken by our university ensure that the dose rate is less than the standard permissible limit at any point of concern. The maximum storage capacities for 137Cs and 60Co are estimated to be 4.88×1013 Bq and 9.99×1010 Bq, respectively.关键词：Radioactive sources storehouse;Radiation field;Maximum storage capacity of the radioactive sources storehouse;MCNP
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发布时间：2021-12-10
RADIATION PROTECTION
- 摘要：Based on the study of radiation-induced random telegraph signal (RTS) noise in CMOS active pixel sensors, we propose a real-time auto-detection method for RTS detection, reconstruction, and parameters extraction. 60Co γ-ray radiation experimental results reveal that, using the proposed method and employing the standard deviation of real-time Gaussian noise as the detection threshold, 257 out of 282 multilevel RTS transitions were successfully detected, thus, indicating a detection efficiency of 91%. This detection efficiency is 16% higher than that obtained in the detection method that uses signal standard deviation as the detection threshold.关键词：Random telegraph signal;Dark signal;Radiation;Charged particle tracking;Threshold based detection
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发布时间：2021-12-10
RADIATION INTERDISCIPLINARY RESEARCH
- 摘要：This study explores the protective effect of compound raspberry seed powder on the bone marrow cells of acute radiation-injured mice. In the experiment, an acute radiation injury model was generated in mice. A blank control group, a model control group, and treatment groups of different concentrations of compound raspberry seed powder solution (low/medium/high dose group) were established. After irradiation, the changes in nucleus cells, micronucleus rate, cell cycle, and mitochondrial membrane potential of mice bone marrow cells were measured. Compared with the blank control group, the model control group and treatment groups were significantly different (p < 0.01).Compared with the model control group, the number of nucleated cells increased by 78.2% (p < 0.01) and 116.9% (p < 0.01), respectively, in the medium, and high dose groups, and the micronucleus rate in the high dose group decreased by 27.3% (p < 0.01). The proportion of cells in the G1 phase and S phase in the medium dose group and in the S phase of high dose group was increased (p < 0.05). The proportion of cells in the G1 phase of the high dose group increased significantly (p < 0.01). The mitochondrial membrane potential of bone marrow cells in the medium and high dose groups was significantly increased (p < 0.01). The results indicated that compound raspberry seed powder increased the number of bone marrow cells, reduced the micronucleus rate, increased the mitochondrial membrane potential, reduced cell cycle arrest, and inhibited the induction of apoptosis by irradiation damage in bone marrow cells, which suggested that compound raspberry seed powder may play an important role in the protection of bone marrow cells injured by irradiation.关键词：Acute radiation injury;Compound raspberry seed powder;Bone marrow cells;Injury;Apoptosis;Radiation protection
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发布时间：2021-12-10 - 摘要：The whole thorax of C57BL/6 female mice was irradiated to a single absorbed dose of 15 Gy. The formation of radiation-induced pulmonary fibrosis (RIPF) was assessed by lung index, Masson staining, Ashcroft score, and collagen synthesis for 20 weeks after irradiation. TGF-β1 was measured by ELISA assay, and the major proteins in TGF-β1/Smad-dependent pathway, including TGF-β, TβR, phosphor-Smad 2/3, and Smad 7, were detected by immunohistochemistry staining. The results showed that RIPF formation was significantly reduced when CpG-ODN was administered to mice irradiated. Expression of TGF-β1, a profibrotic cytokine, remained at a lower level. In TGF-β1-Smad-dependent pathways, TGF-β1, TβR, and phosphor-Smad 2/3 were downregulated, while Smad 7 was upregulated. This suggested that CpG-ODN prevented RIPF. The mechanism might be associated with a reduction of profibrogenic cytokine TGF-β1 and inhibition of the fibrosis-related downstream TGF-β1-Smad-dependent pathway.关键词：Radiation induced pulmonary fibrosis;CpG-ODN;TGF-β1;Smad protein
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发布时间：2021-12-10 - 摘要：Sixty male mice were divided into six groups:normal control group (0 Gy), model control group (1.0 Gy), positive control group (1.0 Gy+523 tablet), and cimetidine groups (1.0 Gy) at the doses of 33.3, 100, and 300 mg/kg, respectively. The mice were irradiated to absorbed dose of 1.0 Gy with 60Co γ-rays at 8.33 mGy/min. Cimetidine was administered intragastrically 6 d before irradiation and 5 h after irradiation separately. Twenty-four hours after irradiation, the apoptosis rate of spleen lymphocytes, T lymphocyte subsets, and B lymphocytes in spleen, the content of IL-2, IL-4, IL-6, IL-12, IFN-γ, and TNF-α in serum were detected. Compared with normal control group, the apoptosis rate of spleen lymphocytes increased significantly (p < 0.01). The percentage of CD3+, CD3+CD8+ T lymphocytes, CD3−CD19+ B lymphocytes, and the content of IL-4, IL-12, and TNF-α in serum decreased significantly (p < 0.01, p < 0.05). Compared with model control group, the apoptosis rate of spleen lymphocytes decreased (p < 0.01), while the content of IL-4, IL-6, IL-12, IFN-γ, and TNF-α increased in serum of cimetidine groups (p < 0.01, p < 0.05). The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3−CD19+ cells increased in 300 mg/kg cimetidine group (p < 0.01, p < 0.05). Cimetidine could improve the immune functions of mice irradiated by γ-rays to 1.0 Gy.关键词：Cimetidine;Low-dose-rate radiation;Immune function;Apoptosis
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发布时间：2021-12-10
RADIOBIOLOGY AND RADIOMEDICINE
- 摘要：Due to the operation of nuclear reactors, the nuclear graphite used in these reactors contains large amount of radionuclides. Tritium is considered one of the most important radionuclides, which should be specially treated because of its high concentration and the ease of entering the environment via isotopic reaction with water. According to relevant studies worldwide, thermal treatment is the most applicable technology for the removal of tritium; however, the efficiency of the removal is influenced by the process parameters. The removal temperature should be higher than 600℃, and the removal efficiency increases with increasing flow rate of the carrier gas and upon addition of steam to the carrier gas. Most significantly, the tritium removal efficiency is greatly influenced by the nature and working condition of the graphite. Current research in this field is mostly qualitative. To optimize tritium removal rates, the process should be systematically studied with respect to the different process parameters involved. However, there have been few such studies reported in China. This manuscript summarizes the main findings of various international research groups regarding tritium removal from nuclear graphite, in order to provide some guidance to related domestic researches.关键词：Decomtamination of nuclear graphite;Thermal treatment;Tritium
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发布时间：2021-12-10
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