检索结果-南通市图书馆

Hierarchical Microphase Behaviors of Chiral Block Copolymers under kinetic and Thermodynamic control

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2022年第7期4卷 2460-2468页

作者： Zhen Geng Huiying Wang Seon-Mi Jin Xinghao Yan Min Ren Bijin Xiong Ke Wang Renhua Deng Senbin Chen Eunji Lee Lianbin Zhang Jintao Zhu Zhenzhong Yang State Key Laboratory of Materials Processing and Die&Mould Technology Key Laboratory of Materials Chemistry for Energy Conversion and Storage of Ministry of EducationSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074 School of Materials Science and Engineering Gwangju Institute of Science and Technology(GIST)Gwangju 61005 Institute of Polymer Science and Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084

Chiral superstructures in confined spaces are subtly affected by the complex interplay among various noncovalent interactions,details of which are still in adequately ***,we report the threedimensional confined assembly of the chiral block copolymers of polystyrene-block-poly(D-lactide)andits enantiomer in emulsion droplets and demonstrate unprecedented successive microphase transformations from single helices to double helices with inverted helicity,and then to twisted cylinders in the constructedcolloidal *** structural transformations of chiral microphases are kinetically dependent and can further transform into thermodynamically stable achiral cylinders with saddle-shaped topology upon solvent *** formation and subsequent structural transformations as well as thefinal degeneration of chiral architectures provide guidance to understand the chiral evolution at different length scales within spherical confined space and to fabricate biomimetic systems.

关键词： chiral block copolymers helical structures confined assembly kinetic control mesoporous chiral nanochannels

controlling the lateral and vertical dimensions of Bi2Se3 nanoplates via seeded growth

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2015年第1期8卷 246-256页

作者： Awei Zhuang Yuzhou Zhao Xianli Liu Mingrui Xu Youcheng Wang Unyong Jeong Xiaoping Wang Jie Zeng Hefei National Laboratory for Physical Sciences at the Microscale Collaborative Innovation Center of Suzhou Nano Science and Technology Center of Advanced Nanocatalysis (CAN-USTC) & Department of Chemical Physics University of Science and Technology of China Hefei Anhui 230026 P. R. China Department of Materials Science and Engineering Yonsei University 134 Shinchon-dong Seoul Korea

Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi2Se3 nanoplates with modifiable morphology. By manipulating the rate at which precursor solutions were injected into seeds solution with syringe pumps, two distinctive growth modes could be realized. With a fast injection, the thickness of Bi2Se3 nanoplates slightly increased from N7.5 nm （seeds） to -9.5 nm while the edge length grew up from ~160 nm （seeds） to N12 ~tm, after 6 successive rounds of seeded growth. With a slow injection, the thickness and edge length increased simultaneously to -35 nm and -6 b^m after 6 rounds of growth, respectively. These two modes could be viewed as a competition between atomic deposition and surface migration. The products showed interesting, thickness-dependent Raman properties. In addition, NIR transparent, highly conductive and flexible Bi2Se3 thin films with different thicknesses were constructed by the assembly of the as-synthesized Bi2Se3 nanoplates. This approach based on seeded growth and kinetic control can significantly promote the development of versatile nanostructures with diverse morphology.

关键词： bismuth selenide nanoplates seeded growth kinetic control

Flash nanocomplexation (FNC): A new microvolume mixing method for nanomedicine formulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第10期35卷 39-52页

作者： Keyang Li Yanan Wang Yatao Xu Guohua Shi Sixian Wei Xue Zhang Baomei Zhang Qiang Jia Huanhua Xu Liangmin Yu Jun Wu Zhiyu He Frontiers Science Center for Deep Ocean Multispheres and Earth Systems Key Laboratory of Marine Chemistry Theory and TechnologyMinistry of Education/Sanya Oceanographic InstitutionOcean University of ChinaQingdao/Sanya 266100/572024China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266003China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Guangzhou City Polytechnic Guangzhou 510520China National Key Laboratory for the Modernization of Classical and Famous Prescriptions of Chinese Medicine Jiangxi University of Chinese MedicineNanchang330004China Division of Life Science The Hong Kong University of Science and TechnologyHong Kong SAR 999077China

The application of nanotechnologies in formulation has significantly promoted the development of modern medical and pharmacological science, especially for nanoparticle-based drug delivery, bioimaging, and theranostics. The advancement of engineering particle design and fabrication is largely supported by a better understanding of how their apparent characteristics(e.g., size and size distribution, surface morphology, colloidal stability, chemical composition) influence their in vivo biological performance, which raises an urgent need for practical nanoformulation methods. Based on turbulent flow mixing and the self-assembly of molecules in fluids, flash technologies emerged as effective bottom-up fabrication strategies for effective nanoformulation. Among the flash technology family, flash nanocomplexation(FNC) is considered a novel and promising candidate that can promote and optimize formulation processes in a precise spatiotemporal manner, thus obtaining excellent fabrication efficiency, reproducibility and expandability. This review presents an overview of recent advances in fabricating drug-delivery nanoparticles using FNC platforms. Firstly, brief introductions to the basic principles of FNC technology were carried out, followed by descriptions of turbulent microvolume mixers that have significantly promoted the efficiency of FNC-based fabrications. Applications of real formulation cases were then categorized according to the self-assembly-driven interactions(including electrostatic interaction, coordination interaction,hydrogen bonding and hydrophobic interaction) and discussed to reveal the progressiveness of fabricating nanoparticles and discuss how its flexibility will provide advances and replenish the philosophy of nanomedicine formulation. In the end, the commercial potential, current limitations, and prospects of FNC technology for nanoformulation will be summarized and discussed.

关键词： Nanoformulation Nanoparticles Self-assembly Flash nanocomplexation kinetic control Drug delivery

Protease-catalyzed Synthesis of Bz-Arg-Gly-Asp-OMe in Full Aqueous Medium

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2007年第6期23卷 693-696页

作者： HOU Rui-zhen LI Hong-mei LIU Yun-jia ZHANG Long XU Li ZHANG Xue-zhong Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun 130021 P. R. China College of Chemical Engineering Changchun University of Technology Changchun 130012 P. R. China College of Food Engineering Jilin Agricultural University Changchun 130015 P. R. China

Synthesis of N-benzoyl-argininylglycylasparagine methyl ester（ Bz-Arg-Gly-Asp-OMe）, a precursor tripeptide of Arg-Gly-Asp） was catalyzed by papain under kinetic control, at alkaline pH, in a full aqueous medium. The substrates were N-benzoyl-argininylglycine ethyl ester and asparagine dimethyl ester. An aqueous solution of 0. 1 mol/L KCl/NaOH containing 8 mmol/L EDTA and 2 mmol/L DTT was selected as the reaction medium. The synthesized hydrophilic tripeptide was soluble in the reaction medium during the reaction process, however, the secondary hydro- lysis of the tripeptide product was not considerable. The effects of different factors, including water content, temperature, reaction time, and molar ratio of the substrates, on the yield of Bz-Arg-Gly-Asp-OMe were examined. The optimal reaction conditions were 0. 05 mol/L Bz-Arg-Gly-OEt and 0. 15 mol/L Asp（ -OMe）2·HCl in 0. 1 mol/L KCl/ NaOH solution（pH 8.5）, at 40 ℃, and a reaction time of 60 min, with a maximum conversion yield of 62.4%.

关键词： RGD Peptide synthesis Papain kinetic control

kinetically controlled Carboxypeptidase-Catalyzed Synthesis of Novel Antioxidant Dipeptide Precursor BOC-Tyr-Ala

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2018年第6期24卷 513-521页

作者： Yuyao Shan Wei Qi Mengfan Wang Rongxin Su Zhimin He State Key Laboratory of Chemical Engineering School of Chemical Engineering and Technology Tianjin University Tianjin 300350 China Tianjin Key Laboratory of Membrane Science and Desalination Technology Tianjin 300350 China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300350 China

Recently, enzymatic peptide synthesis has drawn increasing attention due to its eco-friendly reagents and mild conditions, as compared to traditional chemical peptide synthesis. In this study, we successfully produced an important antioxidant dipeptide precursor, BOC-Tyr-Ala, via a kinetically controlled enzymatic peptide synthesis reaction, catalyzed by the recombinant car- boxypeptidase Y （CPY） expressed in P. pastoris GS 115. In this reaction, the enzyme activity was 95.043 U/mL, and we used t-butyloxycarbonyl-L-tyrosine-methyl ester （BOC-Tyr-OMe） as the acyl donor and L-alanine （L-Ala） was the amino donor. We optimized the reaction conditions to be： 30 ℃, pH 9.5, organic phase （methanol）/aqueous phase = 1：20, BOC-Tyr-OMe 0.05 mol/L, Ala 0.5 mol/L, and a reaction time of 12 h. Under these conditions, the dipeptide yield reached 49.84%. Then, we established the kinetic model of the synthesis reaction in the form of Michaelis-Menten equation according to the con-centration-time curve during the process and the transpeptidation mechanism. We calculated the apparent Michaelis constant K^（app）mand the apparent maximum reaction rate r^（app）max to be 2.9946 x 10^-2 mol/L and 2.0406 x 10.2 mmol/（mL h）, respectively.

关键词： Antioxidant dipeptide precursor kinetic control Reaction kinetic model Enzymatic peptide synthesis

Light-controlled Chemical Reaction Pathways in Disulfide-Based Nonequilibrium Systems

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第6期6卷 1571-1580页

作者： Yingshuai Zhao Peng Zhao Jingyi Zhang Yuanfeng Zhao Bohan Li Guoxiu Hao Yuanyuan An Wei Zhou Yan Lu Lien-Yang Chou Yijun Zheng School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210

Pathway selection in a complex chemical reaction network(CRN)enables organisms to adapt,evolve,and even learn in response to changing *** by this,herein we report an artificial system,where light signal was used to manipulate the reaction pathways in a disulfide-based nonequilibrium *** changing the photon energy and irradiation window,the anion or new radical-mediated pathways were selectively triggered,resulting in a user-defined evolution *** photodissipative cycles were achieved by UV(365 nm)irradiation,increasing the total number of reactions from 3 to *** emerging pathway selection of the CRN is accurately predictable and controllable even in complex organo-hydrogel *** demonstrate up to five-state autonomous sol-gel transitions and the formation of fuel-driven dissipative organo-hydrogel through both chemical and light *** work represents a new approach to allowing CRNs to communicate with the environment that can be used in the development of materials with lifelike behaviors.

关键词： chemical reaction networks light regulation kinetic control pathway selection disulfide

Deterministic Synthesis of Pd Nanocrystals Enclosed by High-Index Facets and Their Enhanced Activity toward Formic Acid Oxidation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Precision Chemistry 2023年第6期1卷 372-381页

作者： Maochang Liu Siyu Zhou Sang-Il Choi Younan Xia The Wallace H.Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory UniversityAtlantaGeorgia 30332United States International Research Center for Renewable Energy State Key Laboratory of Multiphase FlowXi’an Jiaotong UniversityXi’anShanxi 710049P.R.China School of Chemical and Biomolecular Engineering Georgia Institute of TechnologyAtlantaGeorgia 30332United States School of Chemistry and Biochemistry and School of Chemical and Biomolecular Engineering Georgia Institute of TechnologyAtlantaGeorgia 30332United States

Noble-metal nanocrystals enclosed by high-index facets are of growing interest due to their enhanced catalytic performance in a variety of ***,we report the deterministic synthesis of Pd nanocrystals encased by high-index facets by controlling the rate of deposition(V_(deposition))relative to that of surface diffusion(V_(diffusion)).For octahedral seeds with truncated corners,a reduction rate(and thus deposition rate)faster than that of surface diffusion(i.e.,V_(deposition)/V_(diffusion)>1)led to the formation of concave trisoctahedra(TOH)with high-index *** the reduction was slowed down,in contrast,surface diffusion dominated the growth *** the case of V_(deposition)/V_(diffusion)≈1,truncated octahedra with enlarged sizes were *** the reduction rate was between these two extremes,we obtained concave tetrahexahedra(THH)without or with *** growth patterns were also observed for the cuboctahedral *** the Pd octahedra,concave TOH,and concave THH were tested for electrocatalyzing the formic acid oxidation(FAO)reaction,those with high-index facets were advantageous over the conventional Pd octahedra enclosed by{111}*** work not only contributes to the understanding of surface diffusion and its role in nanocrystal growth but also offers a general protocol for the synthesis of nanocrystals enclosed by high-index facets.

关键词： palladium surface diffusion high-index facet unconventional morphology kinetic control

Enhancing control over the degradation behavior of zinc alloy via MOF coating

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2024年第12期67卷 4074-4086页

作者： Rongsheng Deng Yu Peng Qing Meng Zichun Jiang Qinglin Fang Yingzhi Chen Tong Li Kuo Men Bailiang Wang Luning Wang School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Shunde Graduate School of Science and Technology Beijing Foshan 528399China Department of Orthopedics China-Japan Friendship HospitalBeijing 100029China State Key Laboratory of Advanced Materials for Smart Sensing GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101402China

Zinc and its alloys provide a scalable alternative to the list of biodegradable metals due to its moderate degradation rates and biocompatible degradation ***,one of the challenges impeding their clinical applications is the uncontrollable and unstable interfacial reactions between zinc implants and the corrosive *** this study,we report a facile synthesis of metal-organic framework(MOF)nanocrystal coating with tunable thickness on the high-strength Zn-0.8Li alloy matrix for controlled *** as-obtained dense and uniform MOF nanocrystals form a strong connection with the zinc matrix via coordination bond so as to maintain the mechanical properties,and meantime provide highly rough surfaces exhibiting tunable *** varied MOF coating thus regulate the interface structure between the zinc matrix and corrosive media to control the degradation *** antibacterial activity and biocompatibility are also achieved because of the unique topology morphologies,surface superhydrophilicity,as well as the dynamic Zn^(2+)*** study sheds valuable lights on the design of MOF-functionalized metal implants for practical use and also triggers extensive applications of MOF in biomaterials.

关键词： zinc alloy kinetic control degradation cytocompatibility MOF coating