iScience
·
2023
·Vol. 26
·期 4
·106461-106461
·
IF 5.8
Shuaibo Zhai,Jiaqi Gong,Yifei Feng,Zhongbao Que,Weiwei Mao,Xuemin He,Yannan Xie,Xing’ao Li,Liang Chu
Memristors are promising information storage devices for commercial applications because of their long endurance and low power consumption. Particularly, perovskite memristors have revealed excellent resistive switching (RS) properties owing to the fast ion migration and solution fabrication process. Here, an n-i-p type double perovskite memristor with "ITO/SnO 2 /Cs 2 AgBiBr 6 /NiO x /Ag" architecture was developed and demonstrated to reveal three resistance states because of the p-n junction electric field coupled with ion migration. The devices exhibited reliable filamentary with an on/off ratio exceeding 50. The RS characteristics remained unchanged after 1000 s read and 300 switching cycles. The synaptic functions were examined through long-term depression and potentiation measurements. Significantly, the device still worked after one year to reveal long-term stability because of the all-inorganic layers. This work indicates a novel idea for designing a multistate memristor by utilizing the p-n junction unidirectional conductivity during the forward and reverse scanning.
研究领域:
材料科学
·
电子工程
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
METABOLIC ENGINEERING
·
2024
·
IF 6.8
Qingchen Li,Chenxi Li,Jie Zhong,Yukun Wang,Qinghua Yang,Bingmei Wang,Wenjin He,Jianzhong Huang,Shengyuan Lin,Feng Qi
N-methylserotonin (NMS) is a valuable indole alkaloid with therapeutic potential for psychiatric and neurological disorders, and it is used in health foods, cosmetics, and weight loss supplements. However, environmental challenges and low reaction efficiencies significantly hinder cost-effective, large-scale production of NMS in plants or through chemical synthesis. Herein, we have successfully engineered Escherichia coli strains to enhance NMS production from L-tryptophan using whole-cell catalysis. We developed multiple biosynthesis pathways incorporating modules for serotonin (5-hydroxytryptamine, 5-HT), tetrahydromonapterin (MH₄), and S-adenosylmethionine (SAM) synthesis. To enhance MH₄ availability, we employed a high-activity Bacillus subtilis FolE and minimized carbon flux loss through targeted gene knockouts in competitive metabolic pathways, improving 5-HT production. Additionally, we constructed a comprehensive SAM biosynthesis module to facilitate transmethylation by a selected N-methyltransferase fused with ProS2. These engineered modules were coexpressed in two plasmids within the optimized strain NMS-19, producing 128.6 mg/L of NMS in a 5-L bioreactor using fed-batch cultivation—a 92-fold increase over the original strain. This study introduces a viable strategy for NMS production and provides insights into the biosynthesis of SAM-dependent methylated tryptamine derivatives.
研究领域:
生物技术
·
代谢工程
·
微生物学
·
药理学
✓ 已验证
DOI
PubMed
高影响因子
EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Xi Chen,Xiaojun Liu,Congcong Miao,Pengfei Song,Yubing Xiong
Inimer bears a polymerizable vinyl group and a reactable group, and thus has great potentials in the synthesis of branched and functional polymers. Herein, a strategy was developed for the synthesis of ionic liquid (IL)-like inimer containing a trithiocarbonate moiety and a styryl group. The newly-developed IL-like inimer could be facilely achieved via the neutralization reaction using a carboxyl-contained chain transfer agent (CTA) and an alkaline IL monomer. The IL-like inimer was characterized through proton and carbon nuclear magnetic resonance spectroscopy ( 1 H and 13 C NMR), Flourier transform infrared spectroscopy (FT-IR) and Mass spectroscopy. Moreover, the reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) mediated by the as-prepared IL-like inimer was investigated. The results revealed that branched PNIPAM with tunable molecular weight and degree of branching (DB) could be prepared. Additionally, lower critical solution temperature (LCST) of branched PNIPAM could be adjusted through the feed ratio of IL-like inimer and the monomer in the polymerization process. As a result, our study offers a new technique for the design of functional inimer, as well as broadens the application of ILs in the polymer field.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2021
·
IF 3.927
Qian Ma,Hang Li,Jia Guo,Shushu Chu,Qi Zhang,Ziqiong Lin
Porous SnO 2 /NiO hollow nanofibers with effective surface transmission behavior have been prepared through a facile modified electrospinning method . The introduction of Ni component into the precursor solution can not only regulate the morphological evolution together with the nucleation and crystallization of oxide heterostructures at the elevated temperature action, but also significantly contribute to the enhancement of the gas-sensing performance for testing n-butanol gas. SnO 2 /NiO composites can present the highest response of 199 at the optimum operating temperature of 280 °C toward 100 ppm n-butanol gas, which is 4.5 times than that of pure SnO 2 nanofibers. Meanwhile, the response/recovery times of the sensors can be immensely decreased from 57/16 s of pure sample to 36/10 s as the adding amount of Ni component increasing to 5%, along with the superior selectivity and long-term stability toward n-butanol. The excellent gas-sensing properties of the sensors can be mainly attributed to the flourishing porous one-dimensional (1D) microstructure containing the closely connected p-n heterojunctions of SnO 2 and NiO, which can provide large specific surface areas with a mass of active sites to promote the reaction between n-butanol molecule and O δ− on the surface.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Yingkang Chen,Hang Zhang,Hongmei Li,Junhua Hu,Yan Long,Min Liu
The N-alkylation of amines with tetrahydrofuran (THF) to synthesize pyrrolidine compounds is an economic and environmental benign route. However, current catalytic system often suffered from harsh reaction condition and hazardous reagents. In this work, we developed an alumina nanosheet catalyst with a large amount of medium acid sites for synthesis of N-arylpyrrolidines. Nearly 100% target product yield could be obtained at 190 °C, and this catalyst could be reused at least 5 times without obvious deactivation. NH 3 -temperature programmed desorption (TPD) and pyridine-infrared (py-IR) revealed that the catalytic performance is positively correlated with the content of medium acid sites. In-situ IR spectrum proved that the reaction follows the carbocation mechanism. This work affords a competitive system for green sustainable chemistry.
研究领域:
催化
·
有机化学
·
绿色化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Qian Zhu,Xun Sun,Hong Zhao,Dan Xu,Zhengping Dong
The N, S co-doped carbon nanotube-encapsulated Co nanoparticle (NP) material was prepared by one-pot pyrolysis of cheap precursor materials. As-prepared Co@NSC-800 exhibited excellent catalytic activity in transfer hydrogenation and N-formylation of nitroarenes, and the solvent and hydrogen source were the critical factors affecting the selectivity of aniline and benzamide. Moreover, the synergistic effect between Co NPs and N, S atoms was beneficial to improve the catalytic efficiency of Co@NSC-800; especially, the incorporation of S atoms greatly boosted the selectivity of N-formylation. Despite the use of HCOONH4 (HCOOH) as a hydrogen donor for hydrogenation and formylation of nitroarenes, the special nanotube structure of the Co@NSC-800 catalyst effectively prevented the corrosion of Co NPs and showed excellent durability under harsh reaction conditions. In addition, the catalyst maintained excellent catalytic activity after six cycles and was easily separated using an external magnet. Thus, this study can provide an effective method for the transfer hydrogenation and formylation of nitroarenes.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
DOI
高影响因子
Green Chemical Engineering
·
2022
·
IF 0
Jianguo Liu,Jiangmin Sun,Thishana Singh,Shanshan Lin,Longlong Ma
Although precious transition metals such as palladium, platinum, and iridium are widely used in hydrogenation reactions, the earth-abundant transition metal-catalyzed highly selective semi-hydrogenation of terminal alkynes to terminal alkenes remains poorly developed and a challenge. Herein we demonstrate the excellent selective, cost-effective semi-hydrogenation of terminal alkynes via a novel graphene encapsulated Ni@N/C catalyst. The graphene layer encapsulated nano-catalyst Ni@N/C could significantly avoid metal leaching and improve the stability of the catalyst. The strong interaction of nitrogen with the Ni nanoparticles regulates the activity of Ni towards selective semi-hydrogenation of terminal alkynes. Substrates having un-functionalized as well as functionalized substituents, and substrates having sensitive functional groups (olefins, ketones) which pose a challenge to hydrogenate, were semi-hydrogenated with excellent conversion (up to 99%) and selectivity (up to 99%) under optimized reaction conditions.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
REACTIVE & FUNCTIONAL POLYMERS
·
2020
·
IF 3.333
Lin Chen,Shuangshuang Wang,Yingying Zhang,Yuchao Li,Xiangcai Ge,Guang Li,Liping Wang
In this work, N-hydroxyphthalimide (NHPI) was used as catalyst to cleave C H bonds in polyethylene glycol (PEG) backbones to generate carbon free radicals that reacted with the N N bonds of di-tert-butyl azodicarboxylate (DBAD) to form C N grafts (PEG-g-DBAD). Subsequently, the tert-butoxycarbonyl (-Boc) groups of PEG-g-DBAD were removed by treating with trifluoroacetic acid (TFA) to obtain hydrazino functionalized PEG (PEG-g-NHNH 2 ). The structure of functionalized PEG was confirmed by Fourier transform infrared spectroscopy (FTIR), 1 H nuclear magnetic resonance spectroscopy ( 1 H NMR), elemental analysis and size exclusion chromatography (SEC). Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied to investigate thermal stability and crystallization properties of the functionalized PEG. The synthesized PEG-g-NHNH 2 could be used to toughen epoxy resin (EP). The results of mechanical testing and SEM images indicated that the compatibility between PEG backbones and EP has been improved due to the existing of hydrazino groups . The grafted hydrazine groups could also react with 2-bromoisobutyryl bromide (BIBB) to obtain PEG-g-BIBB which initiated the polymerization of (methyl) methacrylate (MMA) by ARGET-ATRP. Thus, we presented a methodology with high efficiency for hydrazination of PEG under mild condition, and the functionalized PEG might have many potential applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
MONATSHEFTE FUR CHEMIE
·
2023
·Vol. 154
·期 10
·1189-1195
·
IF 1.8
Wang Peng,Shi Huibing,Feng Baolin,Zhao Deming,Wu Haigang
The Ru-catalyzed highly selective alkoxycarbonylation of allenes with aliphatic alcohols (also as solvent) allow to produce useful α , β -unsaturated esters in good to excellent yields at 70 °C. Efficient regioselectivity could be controlled in the presence of N-ligands while the P-ligands had no influence on the conversion of substrates and the chemo/regioselectivity of target products. By involving N-ligand 4,7-dimethyl-1,10-phenanthroline in the catalytic system, α , β -unsaturated esters were obtained with high conversion and chemo/regioselectivity (conversion up to 99%, chemical selectivity up to 99%, regioselectivity of branched ester/linear ester up to 89/11). Graphical abstract
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2011
·
IF 2.546
Lei Li,Xiaoying Du,Jianping Deng,Wantai Yang
Optically active macroporous poly( N -isopropylacrylamide) (PNIPAM) hydrogels were synthesized via free radical copolymerization of NIPAM, helical macromonomer, and cross-linker N , N ′-methylenebisacrylamide. The helical macromonomer not only contained catechol groups but also vinyl groups in side chains. Polyethylene glycols were used as pore-forming agent to give rise to macroporous structures in the optically active hydrogels. The hydrogels were characterized by FT-IR, SEM, DSC , swelling ratio and circular dichroism spectra analyses and exhibited the expected optical activity and macroporous architectures. The chiral resolution tests demonstrated the preferential adsorption of the hydrogels towards d -tryptophan and d -phenylalanine in the corresponding two amino acid enantiomers .
研究领域:
材料科学
·
高分子化学
·
生物化学
✓ 已验证
DOI
高影响因子
BIOMACROMOLECULES
·
2021
·
IF 6.988
Botuo Zheng,Songyi Xu,Xufeng Ni,Jun Ling
Polymerization of N-substituted glycine N-thiocarboxyanhydrides (NNTAs) is a promising pathway to prepare functional polypeptoids benefiting from their tolerance to nucleophilic impurities. However, controlled NNTA polymerization is hard to achieve in amide polar solvents, including N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and N-methyl pyrrolidone (NMP), the only aprotic solvents for many biomacromolecules and polypeptoids. In the present work, we successfully achieve controlled NNTA polymerization in amide polar solvents by adding acetic acid as a promoter. The promotion is applied to the polymerization of sarcosine NTA, N-ethyl glycine NTA, and N-butyl glycine NTA. DMAc, DMF, and NMP are suitable solvents to prepare polypeptoids with designable molecular weights and low dispersities (1.06–1.21). The polysarcosines with high molecular weights are prepared up to 35.2 kg/mol. A kinetic investigation quantitatively reveals that the presence of acetic acid not only accelerates the polymerization, but also suppresses H2S-catalyzed decomposition of NNTAs by decreasing the concentration of H2S dissolved in polar solvents. Benzoic acid is also able to promote the polymerization, while trifluoroacetic acid, phosphoric acid, and phenol are not appropriate promoters. The moderate acidity of acids is essential. l-Methionine, l-tryptophan, and l-phenylalanine, which are dissolved in DMF, initiate the controlled polymerization of sarcosine-NTA in the presence of acetic acid and introduce functional end groups to polysarcosines quantitatively. In DMAc, hydrophilic vancomycin is grafted by poly(N-butyl glycine). The amphiphilic product dissolves in dichloromethane and stabilizes water-in-oil emulsion.
研究领域:
高分子化学
·
材料科学
·
生物技术
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Yuanrong Zhang,Shuaitao Li,Xun Hu,Yanfen Fang,Ran Duan,Qifeng Chen
The construction of heterointerface in photocatalyst is an efficient approach to boost the separation and utilization efficiency of charge carriers, which is challenging and crucial in photocatalysis. Here, the construction of melon-structured carbon nitride/ N -doped WO 3 (MCN/NW x ) heterojunction photocatalyst was achieved by a method of prealcoholysis combined with thermal polymerization, where N -doping of WO 3 was achieved in-situ in the formation of heterojunction. The promoted charge separation efficiency was realized through the charge transfer from the conduction band of N -doped WO 3 to the valence band of the MCN. Density functional theory calculation results showed that the formation of the W–N heteroatom-interface led to the increase of density of states at the heterointerface and decrease of the band gap. The MCN/NW x nanocomposite featured a metallic band structure of the nanocomposite photocatalysts, resulting in the enhanced photocatalytic activity . The photocatalytic hydrogen evolution activity of the MCN/NW 2 was enhanced about 2.5 times than that of MCN. This research provides a novel insight into the construction of a novel heteroatom-junction that boosts the separation efficiency of charge carriers, and thereby improves the photocatalytic activity.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）