分类： 医学、药学 >> 药学 分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2020-02-27
摘要： 2019年12月，自武汉开始我国爆发严重的新型冠状病毒（2019-nCoV）感染疫情，急需开发2019-nCoV治疗药物。冠状病毒非结构蛋白 (Nonstructural protein, NSP) 在病毒基因组复制以及转录过程中起重要作用，在冠状病毒家族中普遍保守，是冠状病毒重要功能蛋白。其中，NSP14蛋白兼具核酸外切酶和甲基转移酶功能，是抗SARS和其他冠状病毒药物研究的重要靶点。序列分析表明, SARS coronavirus (PDB ID: 5nfy) 与武汉华南海鲜批发市场新型冠状病毒分离毒株 (GenBank: MN985325.1)氨基酸序列同源性为98.7%。本研究通过已发表的SARS-NSP14晶体结构 (PDB ID: 5nfy) 进行同源建模，构建2019-nCoV-NSP14的蛋白三维结构模型，对其N端-甲基转移酶以及C端-甲基转移酶结构功能域分别进行虚拟筛选，筛选出了18个对NSP14有抑制活性的化合物。其中沙奎那韦 (Saquinavir)、溴隐亭 (Bromocriptine)、黄芩苷 (Baicalein) 以及金丝桃素 (Hypericin) 能同时作用于NSP14蛋白上述两个重要功能域。该结果提示已知抗HIV药物-Saquinavir以及中药抗病毒重要活性成分-黄芩苷以及金丝桃素，可能以2019-nCoV-NSP14蛋白为靶标，发挥抗病毒效应，可作为抗2019-nCov候选药物进行下一步研究。
分类： 核科学技术 >> 裂变堆工程技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Probabilistic safety assessment (PSA) is important in nuclear safety review and analysis. Because the design and physics of the fluoride salt-cooled high temperature reactor (FHR) differ greatly from the pressurized water reactor (PWR), the methods and steps of PSA in FHR should be studied. The high-temperature gas-cooled reactor (HTR-PM) and sodium-cooled fast reactors have built the PSA framework, and the framework to finish the PSA analysis. The FHR is compared with the PWR, HTR-PM and sodium-cooled fast reactors from the physics, design and safety. The PSA framework of FHR is discussed. In the FHR, the fuel and coolant combination provides large thermal margins to fuel damage (hundreds of degrees centigrade). The tristructural-isotropic (TRISO) as the fuel is independent in FHR core and its failure is limited for the core. The core damage in Level 1 PSA is of lower frequency. Levels 1 and 2 PSA are combined in the FHR PSA analysis. The initiating events analysis is the beginning, and the source term analysis and the release types are the target. Finally, Level 3 PSA is done.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： In radiotherapy, the energy of the rays used could be larger than 10 MeV, which would potentially activate stable nucleus into a radioactive one. The induced reactions on some of the human essential elements are studied to show the probability of changes of nuclei. The Talys1.4 toolkit was adopted as the theoretical model for calculation. The reactions investigated include the (, n) and (, p) channels for the stable Na, Mg, Cl, K, Ca, and Fe isotopes, with the incident energy of ranging from 1 to 30 MeV. It was found that the cross sections for the reactions are very low, and the maximum cross section is no larger than 100 mb. By considering the threshold energy of the channel, the half-life time of the residue nucleus, and the percentage of the element accounting for the weight and its importance in the body, it is suggested to track the radioactive nuclei 22Na, 41Ca, and 42,43K after therapy. The results might be useful for medical diagnosis and disease treatment.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-12
Lu, Ping
Lin, Yin-Hua
Xu, Yan-Peng
Tan, Fei
Jia, Xu-Dong
Lu, Ping
Yang, Zhong-Qi
Wang, Xi-Zhuo
Xu, Yan-Peng
Tan, Fei
Wang, Miao
Xu, De-Rong
摘要： This study investigated the influence of corn straw application on soil microbial communities and the relationship between such communities and soil properties in black soil. The crop used in this study was maize (Zea mays L.). The five treatments consisted of applying a gradient (50, 100, 150, and 200%) of shattered corn straw residue to the soil. Soil samples were taken from May through September during the 2012 maize growing season. The microbial community structure was determined using phospholipid fatty acid (PLFA) analysis. Our results revealed that the application of corn straw influenced the soil properties and increased the soil organic carbon and total nitrogen. Applying corn straw to fields also influenced the variation in soil microbial biomass and community composition, which is consistent with the variations found in soil total nitrogen (TN) and soil respiration (SR). However, the soil carbon-to-nitrogen ratio had no effect on soil microbial communities. The abundance of PLFAs, TN, and SR was higher in C1.5 than those in other treatments, suggesting that the soil properties and soil microbial community composition were affected positively by the application of corn straw to black soil. A Principal Component Analysis indicated that soil microbial communities were different in the straw decomposition processes. Moreover, the soil microbial communities from C1.5 were significantly different from those of CK (p<0.05). We also found a high ratio of fungal-to-bacterial PLFAs in black soil and significant variations in the ratio of monounsaturated-to-branched fatty acids with different straw treatments that correlated with SR (p<0.05). These results indicated that the application of corn straw positively influences soil properties and soil microbial communities and that these properties affect these communities. The individual PLFA signatures were sensitive indicators that reflected the changes in the soil environment condition.
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