Reconstruction of a Food-grade Expression Vector in Lactococcus Lactis

[Objective]In order to improve expression vector of L.lactis at food grade and widen application range of original system.[Method] Taking pNZ8149 as basis,the promoter PnisA of pNZ8149 was inserted L.lactis MG1363 and SPusp45 of unknown secretory protein in downstream.Through PCR technology,specific primers were used to delete restriction sites between promoter sequence and signal peptide gene sequence and ensure better distance between SD sequence and start codon to construct secreting expression vector pNZS.The reporter gene gus was recombined into multiple cloning site of pNZS to construct pNZS-gus and L.lactis was transformed by electroporation.10 ng/ml nisin was used for induction culture,then culture solution was conducted GUS staining test.[Result]The new constructed L.lactis N3900/pNZS-gus system could express active GUS protein and GUS protein could be secreted out of cell.[Conclusion]The successful construction of this system lays foundation for secretion expression study of protein and oral vaccine research.

Morphology effect of zirconia support on the catalytic performance of supported Ni catalysts for dry reforming of methane

An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.

信息妖与数字化世界的信息秩序

信息指反映在主观意识中的对象物的存在和运动状态。信息不依赖于感知者的存在而存在,但依赖于感知者的反映而被提取和表达。被提取、加工、表达的信息形成一种人化的存在,即波普尔所谓世界3——客观知识世界。信息随着其载体的进化而进化,并因此而改变人类的交往方式进而改变社会的存在形态。当数字化技术、PC技术、网络技术、自媒体技术等把世界连为一体的时候,信息爆炸,形成世界4——虚拟世界。世界4又可以解析为4-1、4-2、4-3、4-4,其中4-4是世界4最独特的部分。在线和交互是世界4最重要的特征。在线使一切过程得以超时空、超链接;交互所带来的是参与、互动、即时,每一种交往的可能性都打开更大的信息增殖空间,也带来更大的未知性。世界4所带来的是庞大的不确定性和未来发展的难以预见性,已经且将继续以更大的力度冲击人类现有的社会组织及管理秩序。如今的信息世界与宇宙大爆炸早期的浑沌无序有某种相似,需要与物理世界的"麦克斯韦妖"有某种功能相似性的"信息妖"来拮抗信息熵,以使信息世界达到稳定可持续的秩序性。

高铝粉煤灰负载锰基催化剂的催化氧化NO性能研究

氮氧化物催化氧化是烟气脱硝技术的一个重要发展方向。本工作以具有球形镂空结构的预处理后高铝粉煤灰为载体,以硝酸锰为活性组分源,采用溶胶凝胶法制备锰基NO氧化催化剂,采用扫描电镜(SEM)、X射线衍射仪(XRD)、N_(2)物理吸附、H_(2)程序升温还原分析仪(H_(2)-TPR)和X射线光电子能谱(XPS)等分析测试手段对催化剂的NO催化氧化性能进行深入研究。结果表明,载体粒径、锰负载量、硝酸锰凝胶煅烧温度以及NO催化氧化温度对催化剂催化活性均有较大影响。当载体粒径在100~200目(150~75μm)、锰负载量为8wt%、硝酸锰凝胶煅烧温度为500℃、NO催化氧化温度290℃时,NO催化氧化效果最好,氧化率达到77.8%。SEM结果显示,溶胶凝胶法制备的氧化锰粒子在100~200 nm,且相对均匀负载在载体上。N_(2)-物理吸附表明,催化剂的孔结构主要为介孔,并呈现H3型回滞环。锰基催化剂上化学吸附氧O_(β)的占比和Mn^(4+)浓度随着锰负载量的增加先增大后减小,此趋势与NO催化性能变化趋势一致,表明O_(β)和Mn^(4+)是影响NO催化氧化效果的决定因素。