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Cryo-EM structures for the Mycobacterium tuberculosis iron-loaded siderophore transporter IrtAB

Protein & Cell 2023年第6期14卷 448-458页

作者： Shan Sun Yan Gao Xiaolin Yang Xiuna Yang Tianyu Hu jingxi liang Zhiqi Xiong Yuting Ran Pengxuan Ren Fang Bai Luke WGuddat Haitao Yang Zihe Rao Bing Zhang Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China State Key Laboratory of Medicinal Chemical Biology Nankai UniversityTianjin 300353China Laboratory of Structural Biology Tsinghua UniversityBeijing 100084China National Laboratory of Biomacromolecules CAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of SciencesBeijing 100101China School of Chemistry and Molecular Biosciences The University of QueenslandBrisbaneQueensland 4072Australia CAS Center for Excellence in Molecular Cell Science Shanghai Institute of Biochemistry and Cell BiologyChinese Academy of SciencesShanghai 200031China University of Chinese Academy of Sciences Beijing 100101China Shanghai Clinical Research and Trial Center Shanghai 201210China

The adenosine 5'-triphosphate(ATP)-binding cassette(ABC)transporter,IrtAB,plays a vital role in the replication and viability of Mycobacterium tuberculosis(Mtb),where its function is to import iron-loaded ***,it adopts the canonical type IV exporter ***,we report the structure of unliganded Mtb IrtAB and its structure in complex with ATP,ADP,or ATP analogue(AMP-PNP)at resolutions ranging from 2.8 to 3.5Å.The structure of IrtAB bound ATP-Mg2+shows a“head-to-tail”dimer of nucleotide-binding domains(NBDs),a closed amphipathic cavity within the transmembrane domains(TMDs),and a metal ion liganded to three histidine residues of IrtA in the ***-electron microscopy(Cryo-EM)structures and ATP hydrolysis assays show that the NBD of IrtA has a higher affinity for nucleotides and increased ATPase activity compared with ***,the metal ion located in the TM region of IrtA is critical for the stabilization of the conformation of IrtAB during the transport *** study provides a structural basis to explain the ATP-driven conformational changes that occur in IrtAB.

关键词： ABC exporter-like importer iron-loaded siderophore IrtAB Mycobacterium tuberculosis ABC transporter

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Cryo-EM structures of a prokaryotic heme transporter CydDC

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Protein & Cell 2023年第12期14卷 919-923页

作者： Chen Zhu Yanfeng Shi Jing Yu Wenhao Zhao Lingqiao Li jingxi liang Xiaolin Yang Bing Zhang Yao Zhao Yan Gao Xiaobo Chen Xiuna Yang Lu Zhang Luke W.Guddat Lei Liu Haitao Yang Zihe Rao Jun Li Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China National Clinical Research Center for Infectious Disease Shenzhen Third People's HospitalShenzhen 518112China Laboratory of Structural Biology Tsinghua UniversityBeijing 100084China State Key Laboratory of Medicinal Chemical Biology Nankai UniversityTianjin 300353China Innovative Centerfor Pathogen Research Guangzhou LaboratoryGuangzhou 510005China School of Chemistry and Molecular Biosciences The University of QueenslandBrisbaneQLD 4072Australia

DearEditor,Heme is an essential cofactor required across all kingdoms of life utilized in numerous biological processes,including cellular *** is a prokaryotic ATP-binding cassette(ABC)transporter required for heme assembling in respiratory cytochrome bd oxidase(Georgiou et al.,1987;Poole et al.,1989),a promising target for drug discovery(Borisov et al.,2011).CydDC is thought to play a role in maintaining an optimum periplasmic redox poise that is required for the incorporation of heme cofactors(Yamashita et al.,2014).It also suggested that CydDC is involved in heme processing by mediating glutathione/cysteine translocation(Cook and Poole,2000;Cook et al.,2002),although a role in heme translocation seems unlikely(Yamashita et al.,2014).To date,CydDC has been shown to be important for disulfide bond formation,motility,respiration,and tolerance to nitric oxide and antibiotics(Poole et al.,2019).

关键词： utilized disulfide Poole

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风险投资与公共政策支持研究

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中国科技论坛 2007年第8期 93-96页

作者：徐玉莲梁静溪哈尔滨理工大学经济管理学院黑龙江哈尔滨150040

由于风险投资活动的正外部效应导致市场失灵,因此政府需要制定公共政策对其行业发展提供支持。本文以增加风险资本供给与需求、活跃风险投资市场为目的,分析风险投资家与风险企业家进入风险投资市场的临界条件,最后给出激励风险资本供... 详细信息

由于风险投资活动的正外部效应导致市场失灵,因此政府需要制定公共政策对其行业发展提供支持。本文以增加风险资本供给与需求、活跃风险投资市场为目的,分析风险投资家与风险企业家进入风险投资市场的临界条件,最后给出激励风险资本供需双方进入市场的公共政策建议。

关键词：风险投资公共政策外部效应

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2ASK可见光通信系统的硬件设计与实现

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现代电子技术 2015年第21期38卷 56-59页

作者：梁景熙刘宏展华南师范大学信息光电子科技学院广东广州510006

可见光通信(VLC)是一种基于白光发光二极管(LED)的新颖无线光通信技术,它能够将照明以及通信两大功能合二为一。为了提高传输距离,考虑到白光LED本身带宽有限,提出一种二进制振幅键控(2ASK)调制预处理方案,设计与实现了相应的LED调制发... 详细信息

可见光通信(VLC)是一种基于白光发光二极管(LED)的新颖无线光通信技术,它能够将照明以及通信两大功能合二为一。为了提高传输距离,考虑到白光LED本身带宽有限,提出一种二进制振幅键控(2ASK)调制预处理方案,设计与实现了相应的LED调制发射、解调接收系统。分模块阐述了系统各部分的原理与电路结构,并且在硬件实验中探究该通信系统的性能。结果证明,在调制信号频率为50 k Hz时,该系统最大不失真传输距离达到503 cm,满足低速、较长距离通信的要求。

关键词：可见光通信白光发光二极管二进制振幅键控硬件设计调制效果

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Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device

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Petroleum Science 2024年第2期21卷 1290-1304页

作者： liang-liang Dong Yu-Lin Zhang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina Oil and Gas Equipment Technology Sharing and Service Platform of Sichuan ProvinceChengdu610500SichuanChina

Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable *** structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.

关键词： Water control Flow separation Flow resistance-increasing AICD device Simulation and experiment

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Global existence and large-time behavior for primitive equations with the free boundary

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Science China Mathematics 2024年第10期67卷 2303-2330页

作者： Hai-liang Li Chuangchuang liang School of Mathematical Sciences Capital Normal University Academy for Multidisciplinary Studies Capital Normal University College of Mathematics and Statistics Chongqing University

In the present paper, the primitive equations, which can be used to simulate the large-scale motion of the ocean and atmosphere, are considered in the three-dimensional domain bounded below by a fixed solid boundary and above by a free-moving boundary. The global existence and uniqueness of strong solutions are established, and the long-time convergence to the equilibrium state is shown to be either at an exponential rate for the horizontal periodic domain or at an algebraic rate for the horizontal whole space.

关键词： primitive equations the free boundary value problem global well-posedness large-time behavior

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Sufficient Conditions for Amalgamated 3-Manifolds to be ∂-Irreducible

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 161-172页

作者： Bing FANG Fengchun LEI liang liang School of Mathematical Sciences Dalian University of TechnologyDalian 116024LiaoningChina School of Mathematics Liaoning Normal UniversityDalian 116029LiaoningChina

In this paper,the authors give some sufficient conditions for an amalgamated 3-manifold along a compact connected surface F with boundary to be ∂-irreducible in terms of distances between some kinds of vertex subsets ... 详细信息

关键词： ∂-Irreducibility Irreducibility Amalgamated 3-manifold Curve complex Arc complex

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Reliability Assessment of a New General Matching Composed Network

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China Communications 2024年第2期21卷 245-257页

作者： Zhengyuan liang Junbin liang Guoxuan Zhong Guangxi Key Laboratory of Multimedia Communications and Network Technology School of ComputerElectronics and InformationGuangxi UniversityNanning 530004China Jiangxi Engineering Laboratory of IoT Technologies for Crop Growth Ji’an 343000China

The reliability of a network is an important indicator for maintaining communication and ensuring its stable operation. Therefore, the assessment of reliability in underlying interconnection networks has become an increasingly important research issue. However, at present, the reliability assessment of many interconnected networks is not yet accurate,which inevitably weakens their fault tolerance and diagnostic capabilities. To improve network reliability,researchers have proposed various methods and strategies for precise assessment. This paper introduces a novel family of interconnection networks called general matching composed networks(gMCNs), which is based on the common characteristics of network topology structure. After analyzing the topological properties of gMCNs, we establish a relationship between super connectivity and conditional diagnosability of gMCNs. Furthermore, we assess the reliability of g MCNs, and determine the conditional diagnosability of many interconnection networks.

关键词： conditional diagnosability interconnection networks network reliability super connectivity

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基于方法集和DEA模型的黑龙江省灌溉用水效率评价

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干旱地区农业研究 2019年第6期37卷 124-131页

作者：梁静溪张安康许耀文李晨阳哈尔滨理工大学经济管理学院黑龙江哈尔滨150000 东北农业大学水利与土木工程学院黑龙江哈尔滨150000

为了讨论方法集模型对于灌区用水效率综合评价的可行性,以DEA模型作为对比参照,选取了渠系和田间两方面指标,对黑龙江省20个灌区用水效率进行排序和计算,得出的主要结论:利用方法集模型评价的20个灌区的排序结果均通过Spearman检验,解... 详细信息

为了讨论方法集模型对于灌区用水效率综合评价的可行性,以DEA模型作为对比参照,选取了渠系和田间两方面指标,对黑龙江省20个灌区用水效率进行排序和计算,得出的主要结论:利用方法集模型评价的20个灌区的排序结果均通过Spearman检验,解决了不同评价方法结果不一致的问题,且与DEA模型得出的排序结果一致;通过方法集模型和DEA模型结果可以看出:富裕、永发、安邦河、龙头桥和石龙灌区效率值较低,分别是0.58、0.55、0.54、0.51、0.45,且20个灌区灌溉用水效率与渠系效率平均关联度为1.779,与田间效率平均关联度为1.229,受渠系水利用效率影响较大,受田间水效率影响较小,可采取渠道衬砌,合理规划渠系布局等方式减少渠道输配水环节的灌溉水损失,采取控制灌溉技术,喷、滴灌溉等节水措施,提高灌溉用水效率。

关键词：方法集模型 DEA模型灌溉用水效率综合评价黑龙江省

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Non-interactive SM2 threshold signature scheme with identifiable abort

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Frontiers of Computer Science 2024年第1期18卷 171-185页

作者： Huiqiang liang Jianhua CHEN School of Mathematics and Statistics Wuhan UniversityWuhan 430072China

A threshold signature is a special digital signature in which the N-signer share the private key x and can construct a valid signature for any subset of the included t-signer,but less than t-signer cannot obtain any *** the breakthrough achievements of threshold ECDSA signature and threshold Schnorr signature,the existing threshold SM2 signature is still limited to two parties or based on the honest majority setting,there is no more effective solution for the multiparty *** make the SM2 signature have more flexible application scenarios,promote the application of the SM2 signature scheme in the blockchain system and secure cryptocurrency *** paper designs a non-interactive threshold SM2signature schemebasedon partially homomorphic encryption and zero-knowledge *** the last round requires the message input,so make our scheme non-interactive,and the pre-signing process takes 2 rounds of communication to complete after the key *** allow arbitrary threshold t

关键词： SM2 signature secure multi-party computation threshold signature UC-secure dishonest majority

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