BIOORGANIC CHEMISTRY
·
2019
·
IF 3.926
Zhen Zeng,Xiaoli Yin,Xueyuan Wang,Wuying Yang,Xiaoqin Liu,Yanping Hong
Twenty maslinic acid and corosolic acid derivatives were obtained by coupling with l -amino acids at C-28 position. The α-glucosidase inhibitory activities of the present compounds were evaluated in vitro. Results reveal that some of the derivatives exhibit a better α-glucosidase inhibitory activity than that of acarbose in the test conditions of ethanol-water solution and DMSO. It is worth noting that maslinic acid and corosolic acid derivatives coupled aspartic acid ( 9f : IC 50 = 382 μm and 10f : IC 50 = 364 μm, respectively) have the best water solubility and thus presented higher inhibitory activity than that of acarbose (IC 50 = 484 μm). Unfortunately, all of the derivatives possess lower inhibitory properties of α-glucosidase than those of the parent compounds in the measurement system of DMSO solution, even if the derivatives exhibit better water solubility than that of the parent compounds.
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 139
·期 3
·2079-2087
·
IF 2.471
Ou Juhua,Ge Chao,Kong Zhenxing,Chen Yujing,Dai Zilin
A novel organo-modified α-zirconium phosphate was prepared by intercalating a functional 1,2,2,6,6-pentamethyl-4-(phenyldiethoxysiloxy) piperidine into α-ZrP. The structure of functional α-ZrP (IZrP) was characterized by X-ray diffraction, FTIR and SEM. The thermal stability of the silicon rubber (SR) composite obtained by physically mixing IZrP was investigated by TGA and DSC. The results shown that the maximum decomposition temperature ( T max ) of SR/IZrP composites increased from 514 to 540 °C as the IZrP loading increased from 0 to 5 mass% and a reduction in exothermic enthalpy from 3378 to 1520 J g −1 was observed. The maximum exothermic peak temperature had obvious enhancement from 557 to 593 °C, while in SR/IZrP/AlOH the deteriorated thermal stability was observed at T 0.1 when compared with SR/IZrP. The addition of AlOH into SR/IZrP increased the exothermic enthalpy, prolonging the exothermic process and increasing the maximum exothermic peak temperature. The SEM results revealed that IZrP and AlOH were dispersed in SR with the layered structure.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2019
·
IF 3.218
Yanjie Chen,Shupei Zhang,Xiuhua Li,Hong Dai,Yanyu Lin
A versatile TiO 2 mesocrystals trigged signal amplification photoelectrochemical (PEC) sensing platform was designed for sensitive and accurate determination of α-fetoprotein (AFP). To construct such a biosensor, Bi 2 S 3 nanosheets with notable visible light photoactivity and biocompatibilities were employed as electron transfer mediator as well as a substrate for AFP antigen immobilization. Meanwhile, the Polyethylenimine (PEI) functionalized TiO 2 mesocrystals was used to anchor AFP antibody and the resulting composite Ab-TiO 2 -PEI was utilized as trace tag for signal amplification. The trace tag anchored onto the electrode interface via indirect competitive recognition between free target AFP and immobilized AFP to combine Ab-TiO 2 -PEI. As a result, a cascade structure of band-edge levels formed between TiO 2 mesocrystals and Bi 2 S 3 nanosheets, which notably promoted the photo-to-current conversion efficiency and enhance photocurrent response significantly. By merit of these, the concentration of AFP could be accurately determined through an indirect competitive reaction immunoassay . Upon the optimal condition, this PEC biosensor performed favorable sensitivity, selectivity and reproducibility. Hence, the designed indirect competitive PEC immunoassay possesses a potential application for clinical test and will inspire more development of simple and practical PEC sensor toward different biomolecules.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2019
·Vol. 33
·期 10
·e5165
·
IF 3.259
Fang-Zhu Wu,Feng-Li Yu,Bing Yuan,Cong-Xia Xie,Shi-Tao Yu
A multifunctional nanomaterial (Fe 3 O 4 @SiO 2 @C X @NH 2 ) comprising a magnetic core, a silicon protective interlayer, and an amphiphilic silica shell is successfully prepared. Ru nanoparticles catalyst loaded on Fe 3 O 4 @SiO 2 @C X @NH 2 is used in hydrogenation of α-pinene for the first time. The novel nanomaterial with amphipathy can be used as a solid foaming agent to increase gas–liquid–solid three-phase contact and accelerate the reaction. Under the mild conditions (40 °C, 1 MPa H 2 , 3 h), 99.9% α-pinene conversion and 98.9% cis -pinane selectivity are obtained, which is by far the best results reported. Furthermore, the magnetic nanocomposite catalyst can be easily separated by an external magnet and reused nine times with high selectivity maintaining.
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PREPARATIVE BIOCHEMISTRY & BIOTECHNOLOGY
·
2020
·
IF 1.415
Li Jun Li,Xiao Qing Liu,Xi Ping Du,Ling Wu,Ze Dong Jiang,Hui Ni,Qing Biao Li,Feng Chen
Isoquercitrin is a flavonoid with important applications in the pharmaceutical and nutraceutical industries. However, a low yield and high production cost hinders the industrial preparation of isoquercitrin. In the present study, isoquercitrin was prepared by biotransformation of rutin using α-L-rhamnosidase from Aspergillus niger JMU-TS528 combined with high-speed countercurrent chromatography (HSCCC) purification. As a result, the optimum transformation pH, temperature, and time were pH 4.0, 60 °C, and 60 min, respectively. The Km and Vmax were 0.36 mM and 0.460 mmol/min, respectively. For isoquercitrin production, the optimal rutin concentration and transformation time were approximately 1000 mg/L and 60 min. The rutin transformation rate reached 96.44%. The isoquercitrin was purified to a purity of 97.83% using one-step purification with HSCCC. The isoquercitrin was identified using UPLC-Q-TOF-MS. The comprehensive results indicated that the biotransformation procedure using the α-L-rhamnosidase from A. niger JMU-TS528 combined with HSCCC was a simple and effective process to prepare isoquercitrin, which might facilitate the production of isoquercitrin for industrial use.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Yue Sun,Simeng Shao,Yanfeng Wang,Wenjuan Lu,Pingping Zhang,Qingqiang Yao
For the first time, g-C 3 N 4 @α-Fe 2 O 3 /Co-Pi heterojunctional hollow spheres were successfully fabricated via thermal condensation method followed by solvothermal and photo-deposition treatment, which showed excellent photocatalytical property. Except for the Z-scheme charge transfer between α-Fe 2 O 3 and g-C 3 N 4 , the Co-Pi could further reduce the combination of photogenerated electrons and holes as a hole storage agent, resulting in remarkably enhanced visible-light photocatalytic water splitting activity with the H 2 production rate of 450 μmol h −1 g −1 , which is 15.7 times higher than that of g-C 3 N 4 . Moreover, the photocatalytic activity of the prepared ternary hollow photocatalysts showed almost no significant weakness after five cycles, which indicated their good performance stability. The as-prepared g-C 3 N 4 @α-Fe 2 O 3 /Co-Pi also possessed good activity for overall water splitting with the hydrogen production rate reaching 9.8 μmol h −1 g −1 . This synthesized g-C 3 N 4 @α-Fe 2 O 3 /Co-Pi composite is expected to be a promising candidate for water splitting.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Kejing Wu,Chunyan Yang,Yingming Zhu,Junbo Wang,Xueting Wang,Changjun Liu,Yingying Liu,Houfang Lu,Bin Liang,Yongdan Li
Molybdenum carbide catalysts over activated carbon with different crystal phases were synthesized under controllable carburization atmospheres and temperatures for transfer hydrogenation of Kraft lignin in ethanol to aromatic monomers. Single α-MoC1–x and crystal transformation of α-MoC1–x to β-Mo2C are observed under a CH4/H2 mixture and H2 carburization atmospheres, respectively. The mixed crystal phases of α-MoC1–x and β-Mo2C with different crystallinities under a N2 carburization atmosphere exhibit higher activity with a maximum aromatic yield of 0.5163 g/g Kraft lignin when carburized at 700 °C. The dehydrogenation reaction and Kraft lignin hydrogenation are proposed to explain the synergistic effect of β-Mo2C, base, and α-MoC1–x for the base-promoted transfer hydrogenation process in ethanol, which is confirmed by in situ Fourier transform infrared analysis. This highly efficient process is suitable for the conversion of different lignin feedstock.
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JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2020
·Vol. 24
·期 3
·545-555
·
IF 2.646
Pan Yufu,Luo Yanfang,Li Chengcheng,Wang Rongjing,Yuan Yihao,Li Meng,Na Ping
The present study focused on the preparation, characterization, and application of cerium (Ce) and neodymium (Nd) co-doped lead (PbO 2 ) electrode, i.e., Ti/SnO 2 -Sb 2 O 3 /α-PbO 2 /Ce-Nd-β-PbO 2 . The electrochemical activities of the modified electrode were investigated and compared with those of Ce-PbO 2 , Nd-PbO 2 , and pure PbO 2 electrodes. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology, crystal structure, and elemental states of the modified electrode. The Ce and Nd co-doped PbO 2 electrode had smaller crystal particles, more compact structure, and higher activity of electrocatalysis compared with the single-doped and undoped PbO 2 electrodes. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were also utilized to study the electrochemical response of the modified electrodes. The results show that the prepared Ce-Nd-PbO 2 electrode has the highest O 2 evolution potential (OEP) and lowest charge transfer resistance, suggesting that it has the lower energy consumption than the other three kinds of electrodes. Electrochemical oxidation methyl orange (MO) as a model dye wastewater was studied to evaluate the potential applications of this modified electrode in environmental science. It was found that the Ce-Nd-PbO 2 electrode exhibited higher MO and chemical oxygen demand (COD) removal efficiency than single-doped and pure PbO 2 electrodes.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2018
·Vol. 29
·期 22
·19443-19453
·
IF 2.324
Yang Sen,Xu Dong-wei,Chen Ping,Qiu Hong-fang,Guo Xiang
Popcorn-like α-Fe 2 O 3 /3D graphene sponge (α-F/3DGS) composites have been successfully fabricated by a novel and facile two-step synthetic route combining template-assisted preparation and co-precipitation method for microwave absorption application. The results show that the popcorn-like α-Fe 2 O 3 nanoparticles with an average diameter about 150–200 nm are uniformly encapsulated into the 3DGS exhibiting a porous microstructure with plenty of wrinkles. The composite displays the optimum microwave absorption properties with the minimum reflection loss (RL min ) of − 55.7 dB and the maximum effective microwave absorption bandwidth up to 4.42 GHz (12.30–16.72 GHz) when the thicknesses are merely 1.4 and 1.7 mm, respectively, exhibiting greatly enhanced microwave absorption properties compared to those of some 2D graphene-based microwave absorbing materials. The excellent microwave absorption properties are attributed to the synergistic effect between dielectric loss and magnetic loss mechanism and improvement for the impedance matching behavior. This study paves a way for designing and fabricating lightweight and high performance microwave absorption materials based on 3D graphene composites.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 33
·期 3
·456-464
·
IF 1.835
Xiao Jun-jie,Li Xiu-bing,Wang Xi,Yi Chun-wang,Su Sheng-pei
The effect of temperature-responsive solution behavior of PNIPAM- b -PPEOMA- b -PNIPAM on its inclusion complexation with α -cyclodextrin was studied. The triblock polymer was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization and formed inclusion complexes (ICs) after selective threading of the PEO segment of the triblock polymer through the cavities of α -CD units. For comparison, PPEOMA homopolymer was prepared and the inclusion complexation with α -CD was also studied. The ICs were prepared with α -CD when the polymer was in different conformations by changing the temperature, and the formed ICs were characterized by XRD, 1 H-NMR, TGA and DSC. The solutions of the ICs show temperature-responsive clear/turbid transition or fluidic emulsion/gel transition depending on the concentration of the α -CD added, and the stoichiometry determined by 1 H-NMR and TGA indicates that the stoichiometry of EO to α -CD of the resulted ICs increases with increasing of temperature.
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ANALYTICAL CHEMISTRY
·
2015
·
IF 5.636
Yu Zhang,Gang Hu,Lin Hu,Jimei Song
This paper reports a novel method for identification of two aliphatic position isomers between α-ketoglutaric acid (α-KA) and β-ketoglutaric acid (β-KA) by their different perturbation effects on a Briggs–Rauscher oscillating system, in which tetraaza-macrocyclic complex [NiL](ClO4)2 is used as the catalyst. The ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The experimental results have shown that addition of α-KA into the system does not affect the oscillating patterns, while the presence of β-KA in a dynamic system influences the oscillatory amplitude. A more interesting feature is that, in the presence of a higher concentration of β-KA, there are damped oscillations after the initial spike, followed by quenching (more exactly: very small oscillations) of the oscillations before the subsequent regeneration of oscillations. A qualitative approach was thus established by employing a Briggs–Rauscher system for identification of these two isomers. The concentrations of these two isomers that can be distinguished lie over the range between 5.0 × 10–6 and 2.5 × 10–3 mol/L. A reaction mechanism based on the FCA model has been proposed. An explanation is that β-KA reacts with HOO• radicals to form acetone, whereas the α-KA does not.
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Analytical Methods
·
2015
·Vol. 7
·期 4
·1328-1332
·
IF 1.821
Xiaoyan Yang,Jingyu Li,Junliang Fu
In this article, a label-free photoelectrochemical immunosensor based on a CdS-modified mesoporous TiO2 film has been developed. The CdS quantum dots could be deposited onto the mesoporous TiO2 film by electrochemical deposition, which could enhance the photocurrent intensity in the visible region. Employing specific binding of antigen–antibody, α-fetoprotein (AFP) could be captured on the surface of the modified electrode. Based on the steric hindrances, the photocurrent intensity decreased with the increase in AFP concentration. A linear response from 0.05 ng mL−1 to 20 ng mL−1 was obtained for AFP detection and the detection limit was 0.02 ng mL−1. Moreover, the practical determination of AFP in human serum was also investigated.
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