Catalysts
·
2023
·Vol. 14
·期 1
·23
·
IF 3.9
Zi-Han Zhang,An-Qi Wang,Bao-Di Ma,Yi Xu
The effective synthesis ofN-benzyl cyclo-tertiary amines using imine reductase, key components in natural products and pharmaceutical synthesis, is a green approach. Traditional methods faced challenges with enzyme activity and selectivity. This study focused on enhancingMesorhizobiumimine reductase (MesIRED) for betterN-benzyl cyclo-tertiary amine production. Through alanine scanning and consensus mutation, 12 single-siteMesIRED mutants were identified from 23 candidates, showing improved conversion ofN-benzylpyrrolidine andN-benzylpiperidine. Notably, mutants from I177, V212, I213, and A241 significantly boosted conversions. The best-performing mutant forN-benzylpyrrolidine,MesIREDV212A/I213V(M1), increased conversion from 23.7% to 74.3%. ForN-benzylpiperidine,MesIREDV212A/I177A/A241I(M2) enhanced conversion from 22.8% to 66.8%. Tunnel analysis revealed M1 and M2 have more efficient tunnels for larger product movement compared to wild-typeMesIRED. Using recombinantE. colicoexpressingMesIRED and glucose dehydrogenase (GDH), high conversions were achieved: 75.1% forN-benzylpyrrolidine (M1) and 88.8% forN-benzylpiperidine (M2). A preparative experiment resulted in 86.2% conversion and 60.2% yield forN-benzylpiperidine. This research offers an efficient method for engineering IRED, significantly improving conversion and selectivity forN-benzyl cyclo-tertiary amines, aiding drug synthesis and providing insights into rational design of other enzymes.Keywords:imine reductase;N-benzyl cyclo-tertiary amines;alanine scanning;consensus mutation;whole-cell biocatalysis;coexpression
研究领域:
生物化学
·
酶工程
·
药物合成
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DOI
高影响因子
Small
·
2024
·Vol. 20
·期 45
·2403852
·
IF 13
Xinxin Wang,Chao Wang,Yajing Wang,Min Hao,Shengqiang Cui,Xudong Huang,Chunhui Wang,Jing Chen,Zhenxiang Cheng,Jianli Wang
N-type PbSe thermoelectric materials encounter challenges in improving the power factor due to the single-band structure near the Fermi level, which obstructs typical band convergence. The primary strategy for enhancing the thermoelectric figure of merit (ZT) for n-type PbSe involves reducing lattice thermal conductivity (κ lat ) by introducing various defect structures. However, lattice mismatches resulting from internal defects within the matrix can diminish carrier mobility, thereby affecting electrical transport properties. In this study, n-type AgCuTe-alloyed PbSe systems achieve a peak ZT value of ≈1.5 at 773 K. Transmission electron microscopy reveals nanoprecipitates of Ag 2 Te, the room temperature second phase of AgCuTe, within the PbSe matrix. Meanwhile, a unique semi-coherent phase boundary is observed between the PbSe matrix and the Ag 2 Te nanoprecipitates. This semi-coherent phase interface effectively scatters low-frequency phonons while minimizing damage to carrier mobility. Additionally, the dynamic doping effect of Cu atoms from the decomposition of AgCuTe within the matrix further optimize the high-temperature thermoelectric performance. Overall, these factors significantly enhance the ZT across the whole temperature range. The ZT value of ≈1.5 indicates high competitiveness compared to the latest reported n-type PbSe materials, suggesting that these findings hold promise for advancing the development of efficient thermoelectric systems.
研究领域:
材料科学
·
凝聚态物理
·
能源材料
·
纳米结构工程
·
热电转换
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DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2020
·
IF 3.442
Dafeng Zhang,Changhua Su,Shujuan Yao,Hong Li,Xipeng Pu,Yanling Geng
BiPO 4 /BiOCl p-n heterojunction photocatalysts were successfully prepared by a facile in situ chemical transformation method with the aim of degrading rhodamine B under simulated sunlight. X-ray diffraction, field emission scanning electron microscopy , ultraviolet–visible diffuse reflectance spectroscopy , photoluminescence , and electrochemistry tests were used to characterized the structure, morphology, optical properties , and inhibited recombination of photoinduced charges. BiPO 4 /BiOCl composites exhibited significantly higher photocatalytic activity for the degradation of rhodamine B than pure BiOCl, and the apparent rate constant is 3.18 times higher than that of BiOCl. The significantly increased photocatalytic activity of the BiPO 4 /BiOCl composites can be ascribed to the formation of a p-n heterojunction , which can effectively boost the separation of photoinduced electron-hole pairs during the photocatalytic process. Additionally, the main active species were investigated and a plausible mechanism is proposed.
研究领域:
材料科学
·
环境科学
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DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2022
·
IF 3.269
Xin Li,Taotao Zhan,Yongbo Zhang,Yuqi Su,Maogang He,Ying Zhang
As one of higher n -alkanes, n -dodecane is an important component of surrogate fuels for aviation kerosene, of which the accurate knowledge of its thermophysical properties is necessary for industrial application. The speed of sound in n -dodecane was measured by the Brillouin light scattering (BLS) in the vicinity of the critical point, of which the examined regions are T = (433.49 to 678.84) K along seven isobaric lines at p = (1.85, 2.0, 2.2, 4.0, 6.0, 8.0, and 10.0) MPa. The relative expanded uncertainty of BLS experimental system is estimated to be less than 1.2% with the confidence level of 95% (coverage factor, k = 2). Polynomial representations for the speed of sound in liquid n -dodecane was fitted by the experimental results, and the average absolute deviation and maximum absolute deviation are 0.70% and 1.96%, respectively. Moreover, the accuracy of the multiparameter equation of state proposed by Lemmon were assessed by the experimental speeds of sound in the whole investigated p - T region.
研究领域:
化学工程
·
物理化学
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DOI
高影响因子
Nanoscale Research Letters
·
2020
·Vol. 15
·期 1
·1-10
·
IF 3.578
Wang Shan,Fu Jing,Zhang Fang,Huan Ruirui,Liu Ting,Zeng Xingguo
Abstract A 0D/2D (0-dimensional/2-dimensional) nanostructure was designed by self-assembly of N–C QDs and carboxylated g-C 3 N 4 nanosheets and used as a fluorescence resonance energy transfer (FRET) fluorescent sensor. The N–C QDs/g-C 3 N 4 nanosheets were synthesized via the amino group on the N–C QD surface and the –COOH of the carboxylated g-C 3 N 4 nanosheets. The mechanism of detection of metronidazole (MNZ) by N–C QDs/g-C 3 N 4 nanocomposites is based on FRET between negatively charged N–QDs and positively charged carboxylated g-C 3 N 4 nanoparticles. N–C QDs/g-C 3 N 4 nanostructures displayed good responses for the detection of MNZ at normal temperature and pressure. The decrease in the fluorescence intensity showed a good linear relationship to MNZ concentration within 0–2.6 × 10 −5 mol/L, and the detection limit was 0.66 μM. The novel FRET sensor will have a great potential in clinical analysis and biological studies. Graphical Abstract
研究领域:
分析化学
·
生物医学
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DOI
PubMed
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 18
·5549-5558
·
IF 6.177
Xiaomei Lu,Jingzhong Qin,Chensheng Xian,Jiabao Nie,Xun Li,Jie He,Bing Liu
A catalytic transfer hydrogenation reaction between nitroarenes and saturated N-heterocycles to simultaneously synthesize value-added anilines and unsaturated N-heterocycles is attractive due to its low-cost, atom economic, and environmental-friendly properties. Herein, we report cobalt-based catalysts prepared via a simple pyrolysis method, namely cobalt nanoparticles supported on microporous nitrogen-doped carbon (Co/mNC). The optimized catalyst (Co/mNC-500) showed excellent performance towards the catalytic transfer hydrogenation reaction between nitrobenzene and 1,2,3,4-tetrahydroquinoline, yielding more than 90% aniline and quinoline after a 24 hour reaction. Moreover, this catalytic system was available to a wide scope of substrates, and thus a variety of anilines as well as quinolines, isoquinolines, and indoles could be synthesized in great yields. Characterization and control experiments revealed that Co nanoparticles (Co NPs) were the dominant cobalt species evenly distributed on the microporous nitrogen-doped carbon support, serving as the reaction active centres. Based on the experimental results, a plausible reaction mechanism was proposed, in which Co NPs played an essential hydrogen abstraction and delivery role during the catalytic transfer hydrogenation process.
研究领域:
化学
·
材料科学
·
催化反应
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DOI
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 49
·期 46
·17033-17038
·
IF 4.174
Weichi Liang,Jiali Wen,Yukai Zhao,Meng Zhang,Jiuxing Jiang
A layered aluminophosphate |C14H11NO|2[Al4(HPO4)4F4(H2O)2] (denoted as SYSU-2) with a new topology has been hydrothermally synthesized with N-methyl-9-acridone (NMA) as the organic structure-directing agent. Single-crystal X-ray diffraction analysis reveals that SYSU-2 crystallizes in a triclinic space group P, with the inorganic sheets stacked in an AA sequence. Hydrogen bonds are responsible for the neutral inorganic–organic layer connection. The layer structure of SYSU-2 is constructed by alternating AlO4F2 octahedra and PO4 tetrahedra. The topological analysis of SYSU-2 indicates an independent topology. The NMA layers are self-assembled with π–π interaction. SYSU-2 crystals show interesting dual-band emission fluorescence properties compared with NMA crystals. Under 406 nm UV irradiation, SYSU-2 crystals emit yellow light with two emission bands at 477 and 566 nm, while NMA crystals emit blue light with only one band at 473 nm. The differences may be derived from the difference of stacking orders and distance of NMA molecule layers between the two crystals.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
Journal of Nano Research
·
2017
·
IF 0.511
Wen Juan Dong,Ji Yan Han,Xin Wu,Li Fan,Wen Ting Liang
A novel near-infrared fluorescence quenching method has been developed for the determination of hydrogen peroxide based on N-acetyl-L-cysteine-capped gold nanoparticles (NAC-AuNPs) as a fluorescence probe. The prepared gold nanoparticles with the size of about 1.91 nm exhibited strong near-infrared fluorescence emission at 693 nm with excitation wavelength at 450 nm in aqueous solution. The fluorescence intensity of NAC-AuNPs was quenched dramatically by adding hydrogen peroxide. Therefore, it could be used to detect hydrogen peroxide based on the fluorescence quenching intensity was linear with the concentration of hydrogen peroxide. Under the optimal experimental conditions, the linear range and detection limit were 1.0×10-6 –3.0×10-2 mol/L and 1.0×10-7 mol/L, respectively. The possible quenching mechanism was investigated by time-resolved fluorescence spectroscopy. The proposed method was simple, sensitive and showed good repeatability and stability.
研究领域:
分析化学
·
生物医学工程
·
纳米技术
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2017
·
IF 2.726
Dong Fu,Xue Feng,Pan Zhang
Amino acid ionic liquids (AAILs) including 1-butyl-3-methylimidazolium glycinate ([Bmim][Gly]), 1-butyl-3-methylimidazolium L -lysinate ([Bmim][Lys]) and tetramethylammonium glycinate ([N 1111 ][Gly]) were used to enhance the absorption of CO 2 in N -methyldiethanolamine (MDEA) aqueous solutions. The mole fractions of CO 2 in N 2 + CO 2 gas mixtures ranged from 0.2 to 1.0. The mass fractions of MDEA and AAILs respectively ranged from 0.300 to 0.400 and 0.050 to 0.100. The absorption capacity and absorption rate under series of conditions were presented and the influences of CO 2 partial pressure and the types of AAILs on the absorption performance were demonstrated.
研究领域:
化学工程
·
环境科学
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DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Zhenghong Zhou,Kangfei Hu,Jiawei Wang,Zhibin Li,Yan Zhang,Zhenggen Zha,Zhiyong Wang
An electrochemical synthesis for quinazolines and quinazolinones was developed via a C(sp3)-H amination/C-N cleavage by virtue of the anodic oxidation. The reaction can be carried out in aqueous media under mild conditions to afford the desired products with high yields. The reaction mechanism was proposed after detailed investigation.
研究领域:
有机化学
·
电化学
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DOI
高影响因子
MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 10
·3747-3753
·
IF 4.58
Jia Haiyan,Yang Taotao,Zuo Yinxiu,Wang Wenmin,Xu Jingkun,Lu Limin,Li Ping
The authors describe a voltammetric immunosensor with antibody immobilized on a glassy carbon electrode (GCE) modified with N-doped graphene (N-GS), electrodeposited gold nanoparticles (AuNPs) and chitosan (Chit). The preparation is simple and the thickness of the electrodeposited films can be well controlled. Due to the specific advantages of N-GS, AuNPs and Chit, the electrode has a large specific surface, improved conductivity, high stability. A new label-free immunosensor for the model antigen (alpha fetoprotein, AFP) detection was then designed by employing N-GS-AuNP-Chit as the antibody immobilization and signal amplification platform. Differential pulse voltammetry and electrochemical impedance spectroscopy were used for the characterization of the stepwise assembly process. Under the optimized conditions, at a typical working potential of +0.20 V (vs. SCE), and by using hexacyanoferrate as an electrochemical probe, the immunosensor has a detection limit as low as 1.6 pg mL −1 and a linear analytical range that extends from 5 pg mL −1 to 50 ng mL −1 . AFP was quantified in spiked human serum samples with acceptable precision.
Schematic of sensitive and effective label-free electrochemical immunosensor for the detection of AFP based on N-GS-AuNP-Chit as signal amplification matrix.
研究领域:
生物医学工程
·
分析化学
·
电化学
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DOI
高影响因子
Canadian Journal of Chemistry
·
2018
·Vol. 96
·期 10
·
IF 1.084
Lingdong Li,Fengxiang Zhang,Fangyuan Gai,Hao Zhou,Xiaofang Chi,Hande Wang,Zongbao Zhao (Kent)
To control the pathogen cross contaminations on medical material surface, there is a pressing need to develop antimicrobial materials with highly efficacious surface biocidal activity. In this work, N-chloramine precursors containing a quaternary ammonium unit and perfluorophenyl azide unit were synthesized and covalently immobilized on inert polyurethane (PU) film upon UV light irradiation. The surface modification was confirmed by contact angle, Fourier transform infrared (ATR FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) analyses. After bleaching treatment, satisfactory biocidal activity was achieved for the surface-modified PU films. It was found that the introduced surface QA center contributed an even faster surface contact killing behavior and that precursors with a longer structural linker caused higher surface chlorine content and higher antimicrobial efficacy. This approach provides a novel and facile method that enables the covalent immobilization of N-chloramine precursors on inert polymeric surface to produce durable antimicrobial materials.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）