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Cationic organobismuth complex as an effective catalyst for conversion of CO

Xiaowen ZHANG, Weili DAI, Shuangfeng YIN, Shenglian LUO, Chak-Tong AU

《环境科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 32-37 doi: 10.1007/s11783-008-0068-y

摘要: In order to achieve high-efficiency conversion of CO into valuable chemicals, and to exploit new applications of organobismuth compounds, cationic organobismuth complex with 5,6,7,12-tetrahydrodibenz[c,f] azabismocine framework was examined for the first time for the coupling of CO into cyclic carbonates, using terminal epoxides as substrates and tetrabutylammonium halide as co-catalyst in a solvent-free environment under mild conditions. It is shown that the catalyst exhibited high activity and selectivity for the coupling reaction of CO with a wide range of terminal epoxide. The selectivity of propylene carbonates could reach 100%, and the maximum turnover frequency was up to 10740 h at 120°C and 3 MPa CO pressure when tetrabutylammonium iodide was used as co-catalyst. Moreover, the catalyst is environment friendly, resistant to air and water, and can be readily reused and recycled without any loss of activity, demonstrating a potential in industrial application.

关键词: cationic organobismuth complex     terminal epoxide     carbon dioxide     coupling     cyclic carbonate    

Cationic and amphipathic cell-penetrating peptides (CPPs): Their structures and

Jennica L. Zaro,Wei-Chiang Shen

《化学科学与工程前沿(英文)》 2015年 第9卷 第4期   页码 407-427 doi: 10.1007/s11705-015-1538-y

摘要: Over the past few decades, cell penetrating peptides (CPPs) have become an important class of drug carriers for small molecules, proteins, genes and nanoparticle systems. CPPs represent a very diverse set of short peptide sequences (10?30 amino acids), generally classified as cationic or amphipathic, with various mechanisms in cellular internalization. In this review, a more comprehensive assessment of the chemical structural characteristics, including net cationic charge, hydrophobicity and helicity was assembled for a large set of commonly used CPPs, and compared to results from numerous drug delivery studies. This detailed information can aid in the design and selection of effective CPPs for use as transport carriers in the delivery of different types of drug for therapeutic applications.

关键词: cell penetrating peptides     amphipathic peptides     drug delivery    

Separation/degradation behavior and mechanism for cationic/anionic dyes by Ag-functionalized FeO-PDA

《环境科学与工程前沿(英文)》 2022年 第16卷 第11期 doi: 10.1007/s11783-022-1572-1

摘要:

● PDA-Fe3O4-Ag was made by hydrothermal and oxidation self-polymerization method.

关键词: PDA     Fe3O4     Magnetic adsorbent     Cationic dyes     Anionic dyes    

Erratum to: Multifunctional peptide conjugated amphiphilic cationic copolymer for enhancing ECs targeting

Xinghong Duo, Lingchuang Bai, Jun Wang, Jintang Guo, Xiangkui Ren, Shihai Xia, Wencheng Zhang, Abraham Domb, Yakai Feng

《化学科学与工程前沿(英文)》 2021年 第15卷 第1期   页码 220-220 doi: 10.1007/s11705-020-1995-9

Multifunctional peptide conjugated amphiphilic cationic copolymer for enhancing ECs targeting, penetrating

Xinghong Duo, Lingchuang Bai, Jun Wang, Jintang Guo, Xiangkui Ren, Shihai Xia, Wencheng Zhang, Abraham Domb, Yakai Feng

《化学科学与工程前沿(英文)》 2020年 第14卷 第5期   页码 889-901 doi: 10.1007/s11705-020-1919-8

摘要: Gene therapy has drawn great attention in the treatments of many diseases, especially for cardiovascular diseases. However, the development of gene carriers with low cytotoxicity and multitargeting function is still a challenge. Herein, the multitargeting REDV-G-TAT-G-NLS peptide was conjugated to amphiphilic cationic copolymer poly( -caprolactone-co-3(S)-methyl-morpholine-2,5-dione)- -polyethyleneimine (PCLMD- -PEI) via a heterobifunctional orthopyridyl disulfide-poly(ethylene glycol)- -hydroxysuccinimide (OPSS-PEG-NHS) linker to prepare PCLMD- -PEI-PEG-REDV-G-TAT-G-NLS copolymers with the aim to develop the gene carriers with low cytotoxicity and high transfection efficiency. The multitargeting micelles were prepared from PCLMD- -PEI-PEG-REDV-G-TAT-G-NLS copolymers by self-assembly method and used to load pEGFP-ZNF580 plasmids (pDNA) to form gene complexes for enhancing the proliferation and migration of endothelial cells (ECs). The loading pDNA capacity was proved by agarose gel electrophoresis assay. These multitargeting gene complexes exhibited low cytotoxicity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The high internalization efficiency of these gene complexes was confirmed by flow cytometry. The results of transfection demonstrated that these multitargeting gene complexes possessed relatively high transfection efficiency. The rapid migration of ECs transfected by these gene complexes was verified by wound healing assay. Owing to ECs-targeting ability, cell-penetrating ability and nuclear targeting capacity of REDV-G-TAT-G-NLS peptide, the multitargeting polycationic gene carrier with low cytotoxicity and high transfection efficiency has great potential in gene therapy.

关键词: gene carriers     multitargeting function     ECs     transfection efficiency    

GID complex regulates the differentiation of neural stem cells by destabilizing TET2

《医学前沿(英文)》 doi: 10.1007/s11684-023-1007-9

摘要: Brain development requires a delicate balance between self-renewal and differentiation in neural stem cells (NSC), which rely on the precise regulation of gene expression. Ten-eleven translocation 2 (TET2) modulates gene expression by the hydroxymethylation of 5-methylcytosine in DNA as an important epigenetic factor and participates in the neuronal differentiation. Yet, the regulation of TET2 in the process of neuronal differentiation remains unknown. Here, the protein level of TET2 was reduced by the ubiquitin-proteasome pathway during NSC differentiation, in contrast to mRNA level. We identified that TET2 physically interacts with the core subunits of the glucose-induced degradation-deficient (GID) ubiquitin ligase complex, an evolutionarily conserved ubiquitin ligase complex and is ubiquitinated by itself. The protein levels of GID complex subunits increased reciprocally with TET2 level upon NSC differentiation. The silencing of the core subunits of the GID complex, including WDR26 and ARMC8, attenuated the ubiquitination and degradation of TET2, increased the global 5-hydroxymethylcytosine levels, and promoted the differentiation of the NSC. TET2 level increased in the brain of the Wdr26+/− mice. Our results illustrated that the GID complex negatively regulates TET2 protein stability, further modulates NSC differentiation, and represents a novel regulatory mechanism involved in brain development.

关键词: TET2     GID complex     neural stem cells     differentiation of neurons    

Synthesis, characterization and assessment thermal properties of clay based nanopigments

Mohammad Banimahd KIEVANI, Milad EDRAKI

《化学科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 40-45 doi: 10.1007/s11705-015-1505-7

摘要: Nano-clay based pigments (NCP) are new type of pigments composed of organic dyes and layered silicate-clay nano-particles, and have already been used in polymeric coatings to improve mechanical thermal and stability properties. In this paper, the basic blue 41(BB41) was intercalated into Na - montmorillonite in an aqueous medium. The dye-intercalated montmorillonite was centrifuged, dried, and milled to prepare the nanopigment particles. X-ray diffraction showed an increase in the basal spacing, thus confirming intercalation of the BB41 molecules within the nanostructures of the interlayer spaces. Fourier transform infrared spectroscopy was used for identifying the functional groups and chemical bounding of Na -montmorillonite, BB41 and montmorillonite-BB41. The morphology of NCP was also studied by transmission electron microscopy. Finally, thermo-gravimetric analysis and differential thermograms suggested the thermal stability of the intercalated dye was improved.

关键词: nanopigment     layered silicate     cationic dye     thermal properties    

Footholds optimization for legged robots walking on complex terrain

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0742-y

摘要: This paper proposes a novel continuous footholds optimization method for legged robots to expand their walking ability on complex terrains. The algorithm can efficiently run onboard and online by using terrain perception information to protect the robot against slipping or tripping on the edge of obstacles, and to improve its stability and safety when walking on complex terrain. By relying on the depth camera installed on the robot and obtaining the terrain heightmap, the algorithm converts the discrete grid heightmap into a continuous costmap. Then, it constructs an optimization function combined with the robot’s state information to select the next footholds and generate the motion trajectory to control the robot’s locomotion. Compared with most existing footholds selection algorithms that rely on discrete enumeration search, as far as we know, the proposed algorithm is the first to use a continuous optimization method. We successfully implemented the algorithm on a hexapod robot, and verified its feasibility in a walking experiment on a complex terrain.

关键词: footholds optimization     legged robot     complex terrain adapting     hexapod robot     locomotion control    

Special issue: Reliability management of complex system

《工程管理前沿(英文)》 2021年 第8卷 第4期   页码 477-479 doi: 10.1007/s42524-021-0175-z

Independent cover meshless particle method for complex geotechnical engineering

Jianqiu WU, Yongchang CAI

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 515-526 doi: 10.1007/s11709-017-0428-4

摘要: A new Independent Cover Meshless Particle (ICMP) method is proposed for the analysis of complex geotechnical engineering. In the ICMP method, the independent rectangular cover regardless of the shape of the analysis model is employed as the influence domain of each discrete node, the general polynomial is employed as the meshless interpolation function of the independent nodal cover, and the Cartesian Transformation Method (CTM) is used for the numerical integration of the nodal covers cut by material interfaces, joints, cracks and faults. The present method has a simple formulation and a low computational cost, and is easy for the numerical analysis and modeling of complex geotechnical engineering. Several typical numerical examples are presented to demonstrate the accuracy and robustness of the proposed method.

关键词: meshless method     particle method     independent cover     CTM     geotechnical engineering    

Forecast method for used number of parts and components based on complex network

LIU Fu-yun, QI Guo-ning, YANG Qing-hai

《机械工程前沿(英文)》 2006年 第1卷 第4期   页码 479-484 doi: 10.1007/s11465-006-0064-5

摘要: Applying directed complex network to model the main structure of a product family, according to in-degree bi-logarithmic coordinate distribution curve and distribution rule of nodes of the network, in-degree evolving rule of nodes of the network is presented and analytic expression of in-degree probability density of nodes is derived. Through the analysis of the relation between existing kinds of components and existing product numbers, an expression of the relation between kinds of components and product numbers is derived. A forecast method for the increment of component numbers and parts based on the increment of products is presented. As an example, the component numbers of an industrial steam turbine product family is forecasted, forecast result verified and forecast error analyzed.

关键词: complex network     industrial     component     analytic expression     forecast    

Amino acid promoted hydrogen battery system using Mn-pincer complex for reversible CO hydrogenation to

《能源前沿(英文)》 2022年 第16卷 第5期   页码 697-699 doi: 10.1007/s11708-022-0843-7

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1255-8

摘要: • Mechanisms of redox reactions of Fe- and Mn-oxides were discussed. • Oxidative reactions of Mn- and Fe-oxides in complex systems were reviewed. • Reductive reaction of Fe(II)/iron oxides in complex systems was examined. • Future research on examining the redox reactivity in complex systems was suggested. Conspectus Redox reactions of Fe- and Mn-oxides play important roles in the fate and transformation of many contaminants in natural environments. Due to experimental and analytical challenges associated with complex environments, there has been a limited understanding of the reaction kinetics and mechanisms in actual environmental systems, and most of the studies so far have only focused on simple model systems. To bridge the gap between simple model systems and complex environmental systems, it is necessary to increase the complexity of model systems and examine both the involved interaction mechanisms and how the interactions affected contaminant transformation. In this Account, we primarily focused on (1) the oxidative reactivity of Mn- and Fe-oxides and (2) the reductive reactivity of Fe(II)/iron oxides in complex model systems toward contaminant degradation. The effects of common metal ions such as Mn2+ , Ca2+, Ni2+, Cr3+ and Cu2+, ligands such as small anionic ligands and natural organic matter (NOM), and second metal oxides such as Al, Si and Ti oxides on the redox reactivity of the systems are briefly summarized.

关键词: Iron oxides     manganese oxides     reduction     oxidation     complex systems     reaction kinetics and mechanisms    

A driving pulse edge modulation technique and its complex programming logic devices implementation

Xiao CHEN,Dong-chang QU,Yong GUO,Guo-zhu CHEN

《信息与电子工程前沿(英文)》 2015年 第16卷 第12期   页码 1088-1098 doi: 10.1631/FITEE.1500111

摘要: With the continual increase in switching speed and rating of power semiconductors, the switching voltage spike becomes a serious problem. This paper describes a new technique of driving pulse edge modulation for insulated gate bipolar transistors (IGBTs). By modulating the density and width of the pulse trains, without regulating the hardware circuit, the slope of the gate driving voltage is controlled to change the switching speed. This technique is used in the driving circuit based on complex programmable logic devices (CPLDs), and the switching voltage spike of IGBTs can be restrained through software, which is easier and more flexible to adjust. Experimental results demonstrate the effectiveness and practicability of the proposed method.

关键词: Driving pulse edge modulation     Switching voltage spike     Complex programmable logic device (CPLD)     Active gate drive    

Percolation-based health management of complex traffic systems

《工程管理前沿(英文)》 2021年 第8卷 第4期   页码 557-571 doi: 10.1007/s42524-021-0174-0

摘要: System health management, which aims to ensure the safe and efficient operation of systems by reducing uncertain risks and cascading failures during their lifetime, is proposed for complex transportation systems and other critical infrastructures, especially under the background of the New Infrastructure Projects launched in China. Previous studies proposed numerous approaches to evaluate or improve traffic reliability or efficiency. Nevertheless, most existing studies neglected the core failure mechanism (i.e., spatio–temporal propagation of traffic congestion). In this article, we review existing studies on traffic reliability management and propose a health management framework covering the entire traffic congestion lifetime, from emergence, evolution to dissipation, based on the study of core failure modes with percolation theory. Aiming to be “reliable, invulnerable, resilient, potential, and active”, our proposed traffic health management framework includes modeling, evaluation, diagnosis, and improvement. Our proposed framework may shed light on traffic management for megacities and urban agglomerations around the world. This new approach may offer innovative insights for systems science and engineering in future intelligent infrastructure management.

关键词: traffic health     health management     critical infrastructure     systems science and engineering    

标题 作者 时间 类型 操作

Cationic organobismuth complex as an effective catalyst for conversion of CO

Xiaowen ZHANG, Weili DAI, Shuangfeng YIN, Shenglian LUO, Chak-Tong AU

期刊论文

Cationic and amphipathic cell-penetrating peptides (CPPs): Their structures and

Jennica L. Zaro,Wei-Chiang Shen

期刊论文

Separation/degradation behavior and mechanism for cationic/anionic dyes by Ag-functionalized FeO-PDA

期刊论文

Erratum to: Multifunctional peptide conjugated amphiphilic cationic copolymer for enhancing ECs targeting

Xinghong Duo, Lingchuang Bai, Jun Wang, Jintang Guo, Xiangkui Ren, Shihai Xia, Wencheng Zhang, Abraham Domb, Yakai Feng

期刊论文

Multifunctional peptide conjugated amphiphilic cationic copolymer for enhancing ECs targeting, penetrating

Xinghong Duo, Lingchuang Bai, Jun Wang, Jintang Guo, Xiangkui Ren, Shihai Xia, Wencheng Zhang, Abraham Domb, Yakai Feng

期刊论文

GID complex regulates the differentiation of neural stem cells by destabilizing TET2

期刊论文

Synthesis, characterization and assessment thermal properties of clay based nanopigments

Mohammad Banimahd KIEVANI, Milad EDRAKI

期刊论文

Footholds optimization for legged robots walking on complex terrain

期刊论文

Special issue: Reliability management of complex system

期刊论文

Independent cover meshless particle method for complex geotechnical engineering

Jianqiu WU, Yongchang CAI

期刊论文

Forecast method for used number of parts and components based on complex network

LIU Fu-yun, QI Guo-ning, YANG Qing-hai

期刊论文

Amino acid promoted hydrogen battery system using Mn-pincer complex for reversible CO hydrogenation to

期刊论文

Redox reactions of iron and manganese oxides in complex systems

Jianzhi Huang, Huichun Zhang

期刊论文

A driving pulse edge modulation technique and its complex programming logic devices implementation

Xiao CHEN,Dong-chang QU,Yong GUO,Guo-zhu CHEN

期刊论文

Percolation-based health management of complex traffic systems

期刊论文