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Crystal structure of the N domain of Lon protease from Mycobacterium avium complex.
Get PDFLon protease is evolutionarily conserved in prokaryotes and eukaryotic organelles. The primary function of Lon is to selectively degrade abnormal and certain regulatory proteins to maintain the homeostasis in vivo. Lon mainly consists of three functional domains and the N-terminal domain is required for the substrate selection and recognition. However, the precise contribution of the N-terminal domain remains elusive. Here, we determined the crystal structure of the N-terminal 192-residue construct of Lon protease from Mycobacterium avium complex at 2.4 å resolution，and measured NMR-relaxation parameters of backbones. This structure consists of two subdomains, the β-strand rich N-terminal subdomain and the five-helix bundle of C-terminal subdomain, connected by a flexible linker，and is similar to the overall structure of the N domain of Escherichia coli Lon even though their sequence identity is only 26%. The obtained NMR-relaxation parameters reveal two stabilized loops involved in the structural packing of the compact N domain and a turn structure formation. The performed homology comparison suggests that structural and sequence variations in the N domain may be closely related to the substrate selectivity of Lon variants. Our results provide the structure and dynamics characterization of a new Lon N domain, and will help to define the precise contribution of the Lon N-terminal domain to the substrate recognition
Organocatalytic, Enantioselective Reductive Bis-functionalization of Secondary Amides: One-Pot Construction of Chiral 2,2-Disubstituted 3-Iminoindoline.
Get PDFWe report the first catalytic, enantioselective reductive bis-functionalization of common amides, which provides a facile access to a variety of 2,2-disubstituted 3-iminoindolines in good yields and with excellent enantioselectivities. The reaction conditions are quite mild and can be run on a gram scale. In this one-pot reaction, three C-C bonds, one ring, and one nitrogen-containing tetrasubstituted carbon stereocenter are created in a catalytic enantioselective manner
锂离子电池三元层状氧化物正极材料失效模式分析
Get PDF镍钴锰三元层状氧化物(NCM)正极材料由于其优越的综合性能在动力/储能电池系统(ESS)领域得到广泛应用。虽然Ni含量的增加可提高三元材料的比容量及电池的能量密度,但相关电池体系的容量保持率和安全性将会变差。如何有效解决该矛盾是此类NCM电池所面临的关键问题。本文从NCM电池体系循环过程中常见的体相结构破坏和正极-电解液界面组成改变两方面失效现象出发,结合近年来国内外对NCM失效模式研究中所提出的新理论、方法、应用,从机械破坏、结构演变、电化学极化、化学副反应、正负极协同效应等多个角度对NCM材料的衰退机理提出见解,对指导电池用户合理制定充放电协议、缓解电动汽车(EV)里程焦虑乃至材料设计本身均有重要的指导及借鉴意义。国家重点研发计划资助（2018YFB0104400,2018YFB0905400
“地小氢”和“月小氢”
Get PDF氢是宇宙中含量最多的元素,与人类的生活密不可分。本文将氢拟人化,使月球上的氢和地球上的氢来了一次亲密互动。通过生动有趣的对话,介绍了氢的发现史和性质,展望了氢在未来不同方面的应用。国家基础科学人才培养基金项目(J1310024
“我”——“三草酸合铁(Ⅲ)酸钾晶体”的生长及影响因素
No full text通过拟人化的手法描述了"我"——"三草酸合铁(III)酸钾晶体"的培养过程及影响"我"生长的一些因素。并以"我"生长成漂亮的翠绿色晶体后,做梦参加宝石选美大赛,透过和绿宝石的一系列精彩对话,展示了"三草酸合铁(III)酸钾晶体"的性质和用途;形象地启发、引导学生对晶体的培养条件和过程以及晶体用途的认识,以激发学生的实验兴趣。2017年福建省本科高校教育教学改革研究项目(FBJG20170295)2017年度厦门大学教学改革研究项目(JG20170204)国家基础科学人才培养基金项目(J1310024
Three-dimensional carbon-based anodes promoted the accumulation of exoelectrogens in bioelectrochemical systems.
Get PDFTo achieve deep understandings on the effects of structure and surface properties of anode material on the performance of bioelectrochemical systems, the present research investigated the bacterial community structures of biofilms attached to different three-dimensional anodes including carbon felt and materials derived from pomelo peel, kenaf stem, and cardboard with 454 pyrosequencing analysis based on the bacterial 16S rRNA gene. The results showed that bacterial community structures, especially the relative abundance of exoelectrogens, were significantly related to the types of adopted three-dimensional anode materials. Proteobacteria was the shared predominant phylum, accounting for 55.4%, 52.1%, 66.7%, and 56.1% for carbon felt, cardboard, pomelo peel, and kenaf stem carbon, respectively. The most abundant OTU was phylogenetically related to the well-known exoelectrogen of Geobacter, with a relative abundance of 16.3%, 19.0%, 36.3%, and 28.6% in carbon felt, cardboard, pomelo peel, and kenaf stem, respectively. Moreover, another exoelectrogen of Pseudomonas sp. accounted for 4.9% in kenaf stem and 3.9% in carbonboard, respectively. The results implied the macrostructure and properties of different anode materials might result in different niches such as hydrodynamics and substrate transport dynamics, leading to different bacterial structure, especially different relative abundance of exoelectrogens, which consequently affected the performance of bioelectrochemical systems. PRACTITIONER POINTS: Bioelectrochemical systems (BESs) represent a novel biotechnology platform to simultaneously treat wastewaters and produce electrical power. Three-dimensional materials derived from nature plant as anode to promote electricity output from BESs and reduce the construct cost of BESs. Macrostructure of the three-dimensional anode material affected phylotype richness and phylogenetic diversity of microorganisms in anodic biofilm of BESs. Geobacter as well-known exoelectrogen was the most abundant in biofilm attached to three-dimensional anode
通过电化学脱氢N—N偶联合成四取代肼化合物（英文）
Get PDF通过电氧化二级芳胺合成了一系列四取代肼化合物.该电合成反应采用简单的装置如单室电解槽和恒电流电解,且无需过渡金属催化剂和氧化试剂,并可放大至克级规模.Project supported by the National Natural Science Foundation of China(No.21672178)the National Foundation for Fostering Talents in Basic Science(No.J1310024)~
一种自供电多传感器无线环境质量监测系统的设计
Get PDF为了实时精确监测既定区域的环境质量状况,解决传统无线传感网因电池不耐用又不能及时更新而导致网络中断的问题,研究设计了一种自供电多传感器的无线环境质量监测系统。所研究设计的无线传感网节点利用太阳能光伏电池板发电完成自供电,并对最大功率点跟踪控制算法进行了优化改进,解决了因电池不能及时充电而导致的传感器节点工作异常的问题,实现了环境质量状况无人值守实时监测。利用数据融合算法,将多节点传感器采集到的数据进行数据融合,通过实验测试表明,所设计系统的测试数据和当地当天中国环境监测总站发布的环境质量状况数据基本吻合。复杂系统优化与大数据处理广西高校重点实验室科研课题资助(No.2017CSOBDP0103);;广西高校科学与技术研究项目(201012MS185);;贵州省科学与技术基金(LKS[2012]34
化学生物学综合实验教材建设
Get PDF高质量实验教材是本科实验教学的重要保证,在创新型人才的培养中发挥着巨大的作用。本文从编写背景、指导思想、项目编写与修订等方面介绍了化学生物学综合实验教材的建设情况。该教材经历了十多年实验教学的考验,能较好满足相关学科的学生培养需要
合成气甲烷化过程模拟与分析
Get PDF针对合成气甲烷化反应,基于吉布斯自由能最小法的热力学模型对反应过程进行了热力学分析,考察了温度、压力、水分对反应过程的影响。基于Ni-ZrO2催化剂和固定床进行了合成气甲烷化实验,根...新疆维吾尔自治区高校科研计划(XJEDU2016S083