最新刊期
期 1 ， 2018
- 摘要：To screen high-yield teicoplanin-producing strain, 60Co γ-ray irradiated spore suspension of the strain Actinoplanes teichomyceticus FIM-16 was spread on regenerating plate containing lethal concentration of teicoplanin. Teicoplanin-resistant mutants were picked and screened by shake-flask fermentation. Strain FIM-16-58 showed two times higher teicoplanin yield than the original strain, and demonstrated higher hereditary stability. There was no obvious effect on the fermentation level of the strain over three generations, and its slope was stable at 4 ℃ for two months. During scale-up experiment in the 1 T fermenter, foam was suppressed effectively by adding 0.1% corn oil, and the yield of teicoplanin reached over 5.0 g/L. Therefore, the high-yield strain laid the foundation of its industrial production and fermentation.关键词：Actinoplanes teichomyceticus;Resistance mutation screening;Radiation mutagenesis;Teicoplanin
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发布时间：2021-12-10 - 摘要：Corncob was irradiated to different absorbed doses (200, 400, 800 kGy) to study the effect of 60Co γ-ray irradiation on separation of cellulose, lignin, and xylan from corncob by formic acid. The cellulose and lignin obtained were subjected to purity measurement and Fourier transform infrared (FT-IR) spectroscopy analysis. The results showed that the energy consumption in crushing corncob decreased, while the degradation degree of cellulose and xylan increased, with increasing absorbed doses. Compared with the control group (0 kGy), corncob cellulose and xylan decreased by 27.68% and 42.19% after irradiation at 800 kGy. With the increase of absorbed doses (200, 400, 800 kGy), the extraction rate of lignin had no significant change, and the extraction rate of corncob cellulose decreased, while that of xylose increased by 14.45%, 41.10%, and 58.63%, respectively; the purity of cellulose increased by 5.77%, 14.53%, and 18.51%, and that of lignin increased by 7.50%, 16.11%, and 18.79%, respectively. The results of FT-IR spectroscopy analysis showed that the cellulose crystallinity and the content of hydroxyl in lignin declined with the absorbed dose increased. It can be concluded that irradiation combined with formic acid treatment can effectively separate cellulose, lignin, and xylan from corncobs and provide technical support for efficient utilization of all components of corncob.关键词：Irradiation treatment;Cellulose;Lignin;Xylan;Formic acid separation process
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发布时间：2021-12-10
RADIATION TECHNOLOGY APPLICATION
- 摘要：Acrylonitrile (AN) monomer was grafted onto polyethylene (PE) non-woven fabric via γ-ray pre-irradiation vapor phase graft polymerization. The grafting ratio (rG) of the PE-g-PAN non-woven fabric was calculated by the weighing method. The effects of temperature, time, and absorbed dose on rG of the PE-g-PAN non-woven fabric were studied. Fourier transform infrared spectroscopy (FTIR), and tension analyses were performed. Contact angle measurement revealed that grafting with AN slightly increased the contact angle of the modified PE-g-PAN nonwoven fabric. Irradiation significantly reduced the mechanical properties of the PE non-woven fabric, while grafting of AN had little effect on its mechanical properties.关键词：Acrylonitrile;Polyethylene;Pre-irradiation graft polymerization;Vapor phase graft polymerization
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发布时间：2021-12-10 - 摘要：The effects of γ-ray irradiation on the supercritical carbon dioxide (scCO2) foaming behavior of polypropylene (PP) were systematically studied. Sheets of PP were prepared through two different methods: irradiation after hot pressing (Sequence I, SI), and hot pressing after irradiation (Sequence II, SII). Carbon dioxide was used as the physical foaming agent. It was found that the crystallinities (51% to 40%) and melting points decreased with the increasing absorbed doses. At low frequency, the complex viscosity of PP decreased after irradiation, and the decrease was more pronounced for PP(SII) than PP(SI). The PP(SI) foam possessed an uniform cell size and a higher foaming rate, and its tensile strength increased from 3.9 MPa to 7.1 MPa compared with those of pure PP and PP(SII). In addition, at the optimum absorbed dose of 30 kGy, the suitable foaming temperature was around 145~153 ℃, and a wider foaming temperature (6~8 ℃) was obtained compared with the original 4 ℃. Therefore, irradiation after hot pressing (i.e., SI) was considered more suitable for the foaming of irradiated PP, resulting in a higher tensile strength and a wider foaming temperature window.关键词：γ-ray irradiation;Polypropylene;Supercritical CO2 foaming;Tensile strength;Rheological property
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发布时间：2021-12-10 - 摘要：We report here a rapid and cost-effective approach for reduction and functionalization of graphene oxide (GO) using ethylenediamine (EDA) in water medium by gamma-ray irradiation in a nitrogen atmosphere. The reduction degree, which can be controlled by varying the absorbed doses (5.3, 15, 20, and 35.3 kGy), was investigated in detail by ultra-violet visible (UV-vis) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffract meter (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). It was found that the GO dispersion changed from yellow to black with increasing absorbed doses. The results of FT-IR, UV-vis, TGA, and XPS demonstrated that the reduction degree increased with absorbed dose and modification of GO with N-H from EDA molecules occurred. The rGO dispersion in water was stable without precipitate. The ratio of C/O reached 7.21 in rGO-at 35.3 kGy. In addition, a reduction mechanism for determining interactions among the EDA molecules, active radicals from the radiolysis of water, oxygen-containing groups on GO sheets, and some EDA molecules attached onto the rGO sheet because of the recombination of radicals is proposed.关键词：Reduced graphene oxide;Graphene oxide;Gamma-ray;Ethylenediamine
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发布时间：2021-12-10
RADIATION CHEMISTRY
- 摘要：In this paper, we conducted a bibliometric analysis of data in Web of Science and CNKI using CiteSpaceV, and HistCite software, and analyzed the literature, authors, institutions, and journals reporting studies on DNA-PKcs. The results showed that from 2006 to 2016, the literature amount on DNA-PKcs research topics in radiation biology increased from 34 to 503. The USA emerged as the country with the most active research in this field, China ranked second in the world in terms of number of papers, and The United States, Germany and Japan are more closely linked. There was a high co-citation frequency between the important academic journals such as DNA Repair, Journal of Biological Chemistry, Molecular and Cellular Biology, and high-impact journals such as Cancer Research, Oncogene, Nature, Cell, indicating that this topic is at the forefront of current scientific research and has witnessed breakthrough results and ideas.关键词：DNA-PKcs;Radibiology;Bibliometrics;Web of Science;CNKI
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发布时间：2021-12-10
RADIATION INTERDISCIPLINARY RESEARCH
- 摘要：Patients with abdominal and pelvic tumors may receive radiotherapy which would cause injury to normal intestinal tissue cells. Recent studies demonstrated that increased hypoxia-inducible factor (HIF) can protect the intestinal tissue from radiation-induced damage. Mechanically, increased HIF could reduce the damage of intestinal epithelial cells and intestinal crypt stem cells to maintain the integrity of epithelial barrier, protecting the intestinal microvascular endothelium cells via up-regulating the expression of vascular endothelial growth factor. Moreover, the up-regulated HIF reduced inflammatory response by regulating the nuclear translocation of NF-kB, the secretion of inflammatory cytokines, and the function of dendritic cells. The relationship between HIF and tumor was also discussed.关键词：Hypoxia-inducible factor;Radiation-induced intestinal injury;Tumor
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发布时间：2021-12-10
REVIEW
- 摘要：Twenty C57BL/6 mice were randomly divided into four groups equally: control, edaravone, radiation (4 Gy), and radiation with edaravone (4 Gy+Eda). Edaravone was dissolved in normal saline at concentration of 45 mg/mL. Mice in the edaravone, and 4 Gy+Eda groups were injected with edaravone intraperitoneally, while mice in control, and 4 Gy groups were injected with normal saline intraperitoneally. Mice in 4 Gy, and 4 Gy+Eda groups were then irradiated by 137Cs γ-rays at a dose of 4 Gy under dose rate of 0.99 Gy/min 30 min after injection. Mice in these four groups were euthanized 15 d after irradiation. Hematology analyzer was used to measure cell counts in peripheral blood. Flow cytometry was used to analyze the percentage of hematopoietic stem and progenitor cells (HSPCs) in bone marrow cells, as well as the levels of reactive oxygen species (ROS) in HSPCs. Colony formation unit-granulocyte macrophage (CFU-GM) assay was used to detect the proliferation of HSPCs. The results showed that compared with those of the control group, the number of peripheral blood leucocytes (WBC), erythrocytes (RBC), and platelet (PLT) in mice in 4 Gy group decreased by 74.16%, 16.63%, and 15.04%, respectively; the percentage of HPC, LSK(Lin- Sca-1+ c-kit+), and CD34+LSK cells decreased by 50.99%, 38.51%, and 14.84%, respectively; the number of CFU-GM in bone marrow cells decreased by 93.44%, and the proportion of CD34-LSK cells increased by 1.74 times; the levels of ROS in HPC and LSK cells increased by 44.11% and 61.43%, respectively. Compared with those of the 4 Gy group, the number of WBC and RBC in mice in 4 Gy+Eda group increased by 58.82% and 9.3%, respectively; the proportion of HPC, LSK, and CD34+LSK cells increased by 1.53 times, 1.5 times, and 14.81%, respectively; the number of CFU-GM in bone marrow cells increased by 57.58%, the percentage of CD34-LSK cells decreased by 49.17%, and the ROS levels of HPC and LSK cells decreased by 38.94% and 55.91%, respectively (p < 0.05). Edaravone exhibits a protective effect on radiation-induced hematopoietic system injury.关键词：Edaravone;Radioprotector;Mice;Hematopoietic system;Reactive oxygen species (ROS)
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发布时间：2021-12-10 - 摘要：The present work focused on the cumulative damage caused by periodically repeated wide-band electromagnetic pulses. The exposure protocol was as follows: electric field intensity E=110 kV/m, 297 kV/m, and 873 kV/m; pulse number N=5, and 100; exposure was repeated 2 times per day, for 2 weeks. 6 h, 1 d, 3 d, 7 d, and 10 d after exposure, the testosterone concentration in blood plasma, superoxide dismutase (SOD) and malondialdehyde (MDA) in the testis, and acrosin activity of sperms were determined by ELISA. The apoptosis rate of spermatogenic cells in the testis was studied by TUNEL, and the survival rate of sperms in the epididymis by CASA. The results showed that compared with single exposure, 28 periodic exposures exhibited a cumulative damaging effect on the reproductive system of male rats. The cumulative effect increased significantly with increasing E and N. Similar to single exposure, the damage caused by repetitive exposure was gradually recovered to a certain degree with prolongation of exposure time.关键词：Wide-band electromagnetic pulse;Repeated exposure;Cumulative damage;Reproductive system;Sperm
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发布时间：2021-12-10
RADIOBIOLOGY AND RADIOMEDICINE
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