Food Analytical Methods
·
2021
·Vol. 14
·期 7
·1464-1471
·
IF 3.366
Zhang Qianchun,Chen Junyu,Wang Yutong,Xia Guangping,Zheng Yuguo,Wang Xingyi,Wu Yun,Zhang Changbo
A novel aptamer solid-phase microextraction (SPME) fibre-based on poly (methacrylic acid-co-ethylene glycol dimethacrylate) for lysozyme-specific recognition has been successfully prepared. The prepared SPME fibres were characterised by various instrumental methods, including scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectrometry. The results showed that the SPME fibre exhibited a porous structure, which is beneficial for the enrichment of the aptamer. The solid-phase microextraction-high-performance liquid chromatography-fluorescence detection (SPME-HPLC-FLD) with the superior selectivity and sensitivity responded linearly to the concentration of lysozyme over the 0.025–10 mg/L range, and the limit of detection was low at 6.8 μg/L, with a linearity of 0.9995. The method showed excellent reproducibility, and the relative standard deviations (RSDs) were less than 5.5%, which facilitated the analysis. The method was applied for the analysis of lysozyme in cow milk and papaya samples, and the recoveries ranged from 86.7–93.5% with RSDs of 4.3–6.1%, which clearly state that the proposed lysozyme aptamer SPME-HPLC-FLD method is a promising analytical tool for the analysis of lysozyme in food samples. Graphical abstract
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 3
·1-9
·
IF 5.833
Li Yanyue,He Yu,Ge Yili,Song Gongwu,Zhou Jiangang
Green emitting copper nanoclusters (G-Cu NCs), yellow emitting Cu NCs (Y-Cu NCs), orange emitting Cu NCs (O-Cu NCs) and red emitting Cu NCs (R-Cu NCs) were prepared using chicken egg white as the stabilizer by changing the reaction conditions. This is a green, facile and cheap method to explore different color emitting CuNCs by the same precursor and stabilizers. The G-Cu NCs were employed for the detection of ethanol due to their aggregation induced emission enhancement (AIEE) effect. The fluorescence emission of Cu NCs at 526 nm under the excitation of 444 nm can be effectively enhanced in the presence of ethanol due to AIEE effect, thus realizing the quantitative determination of ethanol content in the range 5–60%. In addition, a visual dual-emission fluorescence probe with the combination of G-Cu NCs and silicon nanoparticles (Si NPs/G-Cu NCs) was designed to evaluate ethanol content conveniently and rapidly. Desirable linear relationship is observed between ratio of fluorescence intensity (I 525 /I 441 ) and ethanol content under the excitation of 383 nm. Visible color transformation of this probe is observed in the ethanol content range 2–20%. Moreover, the ethanol sensing platforms were applied to the detection and evaluation of the alcohol content of liquor, and the recoveries in liquor were in the range 99.7% to 113%, broadening the applications of Cu NCs and providing a sensitive detection method for ethanol. Graphical abstract
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Reaction Kinetics Mechanisms and Catalysis
·
2021
·Vol. 132
·期 2
·859-876
·
IF 2.081
Zhou Jiading,Li Weimin,Kong Congcong,Li Dongyang,Cui Zhijian,Xue Yinghao,Lu Yuhan,Ren Qinggong
The 1-(3-sulfopropyl)-3-vinylimidazole inner salt was prepared through the reaction of 1-vinylimidazole and 1,3-propanesultone, and then, it was mixed with different acids to synthesize three kinds of vinylimidazole acidic ionic liquids. The three ionic liquids (ILs) were used as catalysts for the catalytic synthesis of trimethylolpropane trioleate, and the effects of the catalyst amount, reaction time, reaction temperature, and molar ratio of reactants on the catalytic activity were studied. The esterification rates obtained using the three ILs as catalysts could reach 95.82%, 95.37%, and 97.88%. The catalytic kinetics of the synthesized ionic-liquid catalyst was studied, and the activation energies of the forward and reverse reactions were 13.9872 kJ mol −1 and 13.9918 kJ mol −1 , and the pre-exponential factors were 2.781 × 10 –2 L mol −1 h −1 and 4.835 × 10 –5 L mol −1 h −1 , respectively. The vinylimidazole acidic ILs showed good catalytic activity in the esterification reaction; thus, the catalysts are suitable for esterification reaction systems and valuable for research. Moreover, the existence of double bonds paves a way for the subsequent research on polymerized ionic liquids.
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Science China-Materials
·
2021
·Vol. 65
·期 1
·95-104
·
IF 8.273
Bao Kepan,Pang Yuepeng,Yang Junhe,Sun Dalin,Fang Fang,Zheng Shiyou
Rational composite design is highly important for the development of high-performance composite polymer electrolytes (CPEs) for solid-state lithium (Li) metal batteries. In this work, Li closo-borohydride, Li 2 B 12 H 12 , is introduced to poly(vinylidene fluoride)-Li-bis-(trifluoromethanesulfonyl) imide (PVDF-LiTFSI) with a bound N -methyl pyrrolidone plasticizer to form a novel CPE. This CPE shows superb Li + conduction properties, as evidenced by its conductivity of 1.43 × 10 −4 S cm −1 and Li + transference number of 0.34 at 25°C. Density functional theory calculations reveal that Li 2 B 12 H 12 , which features electron-deficient multicenter bonds, can facilitate the dissociation of LiTFSI and enhance the immobilization of TFSI to improve the Li + conduction properties of the CPE. Moreover, the fabricated CPE exhibits excellent electrochemical, thermal, and mechanical stability. The addition of Li 2 B 12 H 12 can help form a protective layer at the anode/electrolyte interface, thereby preventing unwanted reactions. The above benefits of the fabricated CPE contribute to the high compatibility of the electrode. Symmetric Li cells can be stably cycled at 0.2 mA cm −2 for over 1200 h, and Li∥LiFePO 4 cells can deliver a reversible specific capacity of 140 mA h g −1 after 200 cycles at 1 C at 25°C with a capacity retention of 98%.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 17
·22232-22244
·
IF 2.478
Liu Ting,Zhai Xiaoyu,Liu Jiaxiang
Indium tin oxide (ITO) is a promising transparent conducting oxide material for photoelectric devices. In this work, the low-resistivity cubic ITO (c-ITO) nanopowders were synthesized via polyacrylamide gel route. The orthogonal experiment design was applied to optimize preparation process that was as follows: n (AM)/ n (MBAM) = 25:6, c (In 3+ ) = 0.3 mol/L, calcination temperature ( T ) = 700 °C, holding time ( t ) = 9 h. Subsequently, the thermal decomposition process of ITO xerogel, crystal structure, morphology, and electrical conductivity of the optimum sample were characterized systematically. The results indicated that the thermal decomposition of ITO xerogel was a multi-step kinetic reaction process, and the activation energy of reaction depended on the conversion of ITO xerogel. The powders were well indexed to cubic ITO crystal phase, and presented a concentrated particle size distribution of 34–54 nm and nearly spherical-like morphology. The low-resistivity value of 0.161 Ω·cm was obtained under the optimum preparation process. Moreover, the formation mechanism of ITO nanopowders prepared via polyacrylamide gel route was also investigated. The synthesized ITO nanopowders with low resistivity present wide application prospects of next-generation ITO functional materials.
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POLYMER JOURNAL
·
2021
·Vol. 53
·期 11
·1259-1267
·
IF 3.08
Zhou Haisen,Wang Yaoyi,Lu Hua
Intracellular delivery of proteins remains challenging. Here, we present a simple and general platform for the efficient loading and delivery of proteins using a methoxy-poly(ethylene glycol)- block -poly(L-phosphotyrosine) (mPEG- b -PpY)-templated calcium phosphate (CaP) hybrid nanoparticle. By doping hybrid CaP nanoparticles with Zn 2+ (CaP-Zn), recombinant proteins bearing a histidine tag can be conveniently loaded by harnessing the His-Zn coordination bond. The resulting protein@CaP-Zn nanoparticles display low toxicity and are tunable, uniform in size, stable under physiological conditions, and degradable in acidic milieu for responsive release. Proteins loaded onto the CaP-Zn nanoparticle can be protected from proteolytic degradation and effectively delivered to intracellular spaces. This work may open up opportunities for protein activity preservation and facilitate the intracellular delivery of recombinant protein therapeutics.
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JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2021
·Vol. 30
·期 3
·1001-1011
·
IF 3.667
Wang Fen,Duo Tongtong,Wang Yongxin,Xiao Zhihong,Xu Airong,Liu Rukuan
In this work, a novel PEI/CG composite was fabricated via a facile one-step strategy at ambient conditions using biodegradable and highly absorbent κ -carrageenan (CG) as a matrix, polyethyleneimine (PEI) as a functional component and poly(ethylene glycol) diglycidyl ether (PGDE) for cross-linking PEI/CG. Systematic investigations were carried out to determine the optimal PEI/CG mass ratio, PGDE/PEI mass ratio and the total concentration of CG and PEI in CG/PEI/PGDE/5 wt% NaOH solution. Batch adsorption experiments have been achieved to investigate the effects of different parameters including solution pH, adsorbent dose, initial Cu 2+ concentration, solution temperature and contact time on the adsorption performance of the composite towards Cu 2+ . Interestingly, the PEI/CG composite showed efficient Cu 2+ adsorption performance. Furthermore, adsorption kinetics, thermodynamics and isotherms have also been investigated to reveal Cu 2+ adsorption behavior and mechanism by the composite during the Cu 2+ adsorption process. In addition, the PEI/CG composite after Cu 2+ adsorption was also investigated with FT-IR and EDS technique to estimate adsorbed Cu 2+ onto the composite. This work opened up new horizons for the fabrication of novel PEI composite with practical application using a facile one-step fabrication strategy.
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2021
·Vol. 193
·期 11
·3624-3640
·
IF 2.926
Jia Dong-Xu,Peng Chen,Li Jun-Liang,Wang Fan,Liu Zhi-Qiang,Zheng Yu-Guo
ω-Transaminase (ω-TA) is an attractive biocatalyst for stereospecific preparation of amino acids and derivatives, but low catalytic efficiency and unfavorable substrate specificity hamper their industrial application. In this work, to obtain applicable ( R )-ω-TA responsible for amination of α-keto acids substrates, the reactivities of eight previously synthesized ω-TAs toward pyruvate using ( R )-α-methylbenzylamine (( R )-α-MBA) as amine donor were investigated, and Gibberella zeae TA (GzTA) with the highest ( R )-TA activity and stereoselectivity was selected as starting scaffold for engineering. Site-directed mutagenesis around enzymatic active pocket and access tunnel identified three positive mutation sites, S214A, F113L, and V60A. Kinetic analysis synchronously with molecular docking revealed that these mutations afforded desirable alleviation of steric hindrance for pyruvate and α-MBA. Furthermore, the constructed single-, double-, and triple-mutant exhibited varying degrees of improved specificities toward bulkier α-keto acids. Using 2-oxo-2-phenylacetic acid ( 1d ) as substrate, the conversion rate of triple-mutant F113L/V60A/S214A increased by 3.8-fold relative to that of wide-type GzTA. This study provided a practical engineering strategy for improving catalytic efficiency and substrate specificity of ( R )-ω-TA. The obtained experience shed light on creating more industrial ω-TAs mutants that can accommodate structurally diverse substrates. Graphical abstract
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METABOLIC BRAIN DISEASE
·
2021
·Vol. 36
·期 7
·2059-2069
·
IF 3.584
Yang Ling,Wang Lijuan,Wang Juan,Liu Ping
Long non-coding RNAs (lncRNAs) play important roles in ischaemic stroke. This study aimed to investigate the role and potential mechanism of lncRNA Gm11974 in ischaemic stroke. Mouse neuroblastoma N2a cells were treated with oxygen–glucose deprivation (OGD). The levels of Gm11974, microRNA-122-5p (miR-122-5p) and semaphorin 3A (SEMA3A) were detected by quantitative real-time PCR (qRT-PCR) or western blot. Cell viability and apoptosis were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, Caspase-3 Assay Kit and flow Cytometry. The levels of oxidative stress indicators were measured by using commercial kits. The relationship between miR-122-5p and Gm11974 or SEMA3A was verified by dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Middle cerebral artery occlusion (MCAO) in mice was used to mimic ischaemic stroke. Gm11974 and SEMA3A were up-regulated, while miR-122-5p was down-regulated in OGD-treated N2a cells and MCAO mice. Down-regulation of Gm11974 ameliorated OGD-mediated N2a cell damage by increasing cell viability and reducing cell apoptosis and oxidative stress. Gm11974 promoted OGD-induced injury in N2a cells via negatively regulating miR-122-5p. Also, miR-122-5p alleviated OGD-resulted N2a cell injury by targeting SEMA3A. Moreover, silencing of Gm11974 decreased infarct volume and neurological score in MCAO mice. Knockdown of Gm11974 attenuated neuronal injury in ischaemic stroke by regulating miR-122-5p/SEMA3A signaling pathway.
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Nano Research
·
2021
·Vol. 15
·期 3
·1809-1816
·
IF 8.897
Geng Shuo,Tian Fenyang,Li Menggang,Liu Yequn,Sheng Jie,Yang Weiwei,Yu Yongsheng,Hou Yanglong
The hydrogen evolution reaction (HER) of molybdenum disulfide (MoS 2 ) is limited in alkaline and acid solution because the active sites are on the finite edge with extended basal plane remaining inert. Herein, we activated the interfacial S sites by coupling with Ru nanoparticles on the inert basal plane of MoS 2 nanosheets. The density functional theory (DFT) calculation and experimental results show that the interfacial S electronic structure was modulated. And the results of Δ G H* demonstrate that the adsorption of H on the MoS 2 was also optimized. With the advantage of interfacial S sites activation, the Ru-MoS 2 needs only overpotential of 110 and 98 mV to achieve 10 mA·cm −2 in both 0.5 M H 2 SO 4 and 1 M KOH solution, respectively. This strategy paves a new way for activating the basal plane of other transition metal sulfide electrocatalysts for improving the HER performance.
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CELLULOSE
·
2021
·Vol. 28
·期 13
·8751-8769
·
IF 5.044
Liu Jinru,Yu Zhicai,He Hualing,Wang Yushu,Zhao Yuhang
Abstract Design and development of fire-resistant composite materials with improved flame retardancy are critically needed for firefighters in fire protection fields. Herein, a novel fire-resistant composite hydrogel (FRCH) was fabricated based on calcium alginate (CA), poly (vinyl alcohol) (PVA) and expandable graphite (EG). The obtained FRCH material displayed prominent flame retardancy due to a large amount of heat was removed as contained water evaporation. Meanwhile, the EG in hydrogel occurred expansion to prevent heat transfer when exposed to fire. Results indicated that peak heat release rate and total release rate of FRCH decreased from 264.9 to 67.2 W/g and 15.4 to 12.1 KJ/g, respectively. The thermal kinetic behavior of FRCH was investigated by using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) models. TPP test further confirmed that introduction of EG in hydrogel prolonged the second-degree skin burn time for 2.73 s compared to without EG component. Besides, benefiting from the expansion behavior of EG when being burned, EG formed a conductive pathway and resulting in LED light up. This work provided an effective way to prepare flame retardant composite material with an early fire warning detection function, which may meet the requirements in firefighting fields. Graphic abstract
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Nature Communications
·
2021
·Vol. 12
·期 1
·1-9
·
IF 14.919
Li Xiaoming,Chen Jiaxin,Yang Dandan,Chen Xi,Geng Dongling,Jiang Lianfu,Wu Ye,Meng Cuifang,Zeng Haibo
Fluorescent type nuclear battery consisting of scintillator and photovoltaic device enables semipermanent power source for devices working under harsh circumstances without instant energy supply. In spite of the progress of device structure design, the development of scintillators is far behind. Here, a Cs 3 Cu 2 I 5 : Mn scintillator showing a high light yield of ~67000 ph MeV −1 at 564 nm is presented. Doping and intrinsic features endow Cs 3 Cu 2 I 5 : Mn with robust thermal stability and irradiation hardness that 71% or >95% of the initial radioluminescence intensity can be maintained in an ultra-broad temperature range of 77 K-433 K or after a total irradiation dose of 2590 Gy, respectively. These superiorities allow the fabrication of efficient and stable nuclear batteries, which show an output improvement of 237% respect to the photovoltaic device without scintillator. Luminescence mechanisms including self-trapped exciton, energy transfer, and impact excitation are proposed for the anomalous dramatic radioluminescence improvement. This work will open a window for the fields of nuclear battery and radiography.
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