查找使用阿拉丁产品的科研文献

Solvent-Free and Highly Efficient Hydrogenation of α-Pinene to Synthesize cis-Pinane by Using Ru Species Immobilized on APTS-Functionalized Cubic Phase NaNbO3

Hu Yin,Chen Wei,Ba Mingwei,Song Weiguo

Solvent-free selective hydrogenation of α -pinene to synthesize cis -pinane with high efficiency has always been a challenge in the catalytic research. The key to achieve this goal is the development of the highly efficient and recyclable catalysts. Cubic NaNbO 3 crystals were functionalized by (γ-aminopropyl)-triethoxysilane (APTS) and decorated with Ru species by a simple solvothermal approach combined with a sol-gel method. And this compound was applied to the catalytic hydrogenation of α -pinene. The crystal phase, chemical structure and surface components of the catalysts were analyzed by X-ray diffraction, field emission transmission electron microscope, X-ray photoelectron spectroscopy, Fourier transform infrared spectra and thermogravimetric analysis. APTS-functionalization of the catalyst surface contributes to the highly dispersed and uniform Ru species with small particle size, leading to the outstanding conversion of α -pinene and selectivity of cis -pinane over NaNbO 3 /APTS/Ru catalyst. The performance of this catalyst is better than that of other similar catalysts, and is comparable to that of commercial Ru/C. The possible mechanisms of the formation of catalyst and the hydrogenation reaction were proposed and discussed. The decrease of catalytic performance after seven cycles should be ascribed to the decomposition and leaching of APTS during the hydrogenation process. The work provides an alternative strategy to design a kind of reusable catalyst with highly efficient hydrogenation performance based on the surface functionalization. Graphical Abstract

Organocatalyzed ring-opening copolymerization of α-bromo-γ-butyrolactone with ε-caprolactone for the synthesis of functional aliphatic polyesters – pre-polymers for graft copolymerization

Chen Gao,Chi-Hui Tsou,Chun-Yan Zeng,Li Yuan,Rui Peng,Xue-Mei Zhang

The comparisons in protective mechanisms and efficiencies among dietary α-lipoic acid, β-glucan and l-carnitine on Nile tilapia infected by Aeromonas hydrophila

Dong-Liang Lu,Samwel Mchele Limbu,Hong-Bo Lv,Qiang Ma,Li-Qiao Chen,Mei-Ling Zhang,Zhen-Yu Du

Dietary α-lipoic acid (LA), β-glucan (Gluc) and l -carnitine (L-Ca) are commonly used additives to promote fish growth and stress resistance in aquaculture production. However their mechanisms and efficiencies in helping fish to resist diseases have not been compared before. In this study, we fed Nile tilapia ( Oreochromis niloticus ) with diets containing appropriate doses of LA, Gluc and L-Ca for five weeks and further intraperitoneally injected the fish with Aeromonas hydrophila . After dietary treatment, none of the additives affected the fish growth, but dietary Gluc and L-Ca reduced protein and lipid body contents in fish, respectively. After A. hydrophila challenge, all fish treated with the three dietary additives showed higher survival rate, but those fed on dietary L-Ca had lower survival than those fed on LA and Gluc diets, indicating high protection efficiency of LA and Gluc. The protective mechanisms of the three feed additives were quite different under A. hydrophila infection. Dietary LA induced higher total antioxidant capacity and higher mRNA expression of anti-oxidative genes than other additives in liver and also activated partly the immune function in serum and spleen. Gluc largely increased the immune function by activating the immunity enzymes in serum, inducing inflammation in liver and increasing the expression of immune genes in spleen and head kidney . Gluc also increased partly the antioxidant capacity in serum and liver and lipid catabolism in liver. L-Ca largely increased lipid catabolism in liver while it increased partly the antioxidant capacities in serum and liver. Taken together, these results indicate that, dietary LA, Gluc and L-Ca have various protective mechanisms and differ in their efficiencies on resisting A. hydrophila infection in Nile tilapia.

Co-production of hydrogen and carbon nanotubes from the decomposition/reforming of biomass-derived organics over Ni/α-Al2O3 catalyst: Performance of different compounds

Limo He,Song Hu,Long Jiang,Guang Liao,Liangping Zhang,Hengda Han,Xiaofang Chen,Yi Wang,Kai Xu,Sheng Su,Jun Xiang

Four types of biomass-derived organics (toluene/1-methylnaphthalene/phenol/ethanol) were catalytically decomposed and steam reformed over Ni/α-Al 2 O 3 for co-production of hydrogen and carbon nanotubes (CNTs). In the decomposition reaction, the oxygen functional group in phenol and ethanol promoted the co-production of hydrogen and CNTs, while a small amount of toluene and 1-methylnaphthalene were cracked to hydrogen and amorphous carbon. In the reforming reaction, the yields of hydrogen and CNTs sharply increased. More than 2000   mmol/(g-cata∗h) of H 2 and 260   mg/(g-cata∗h) of CNTs were produced after the reforming of toluene and ethanol. However, 1-methylnaphthalene was difficult to be reformed and small amount of CNTs were formed. The organics with low molecular weight and low degree of unsaturation conduced to the formation of hydrogen and CNTs. The growth of CNTs on Ni/α-Al 2 O 3 mainly follows the tip-growth mechanism. The diameter distribution of CNTs is not only influenced by Ni particle size, but also related to the different organics and steam addition.

Label-free electrochemical immunoassay for α-fetoprotein based on a redox matrix of Prussian blue-reduced graphene oxide/gold nanoparticles-poly(3,4-ethylenedioxythiophene) composite

Taotao Yang,Haiyan Jia,Zhen Liu,Xinlan Qiu,Yansha Gao,Jingkun Xu,Limin Lu,Yongfang Yu

Herein, a stable and sensitive label-free electrochemical immunosensor for detecting α-fetoprotein (AFP) was proposed based on gold nanoparticles-poly(3,4-ethylenedioxythiophene)/Prussian blue-reduced graphene oxide (AuNPs-PEDOT/PB-rGO) nanocomposite as sensing substrate. PB was used as the electron transfer mediator to provide the electrochemical signal. By utilizing rGO as the supporting material for PB, the stability and intensity of the redox signal were greatly improved. The incorporation of highly conductive AuNPs-PEDOT can further enhance the electrochemical signal and its stability. Electrochemical test showed the anodic current of AuNPs-PEDOT/PB-rGO modified electrode could remain up to 89.45% after 100 cyclic voltammetries . The assembly of PB-rGO and AuNPs-PEDOT exhibited 3D nanostructure and showed high specific surface area, which could effectively capture the antibody of AFP. With the advantages of AuNPs-PEDOT/PB-rGO nanocomposite, the prepared immunosensor showed a sensitive response to AFP in a linear range from 0.01 to 50   ng   mL −   1 with a low detection limit of 3.3   pg   mL −   1 (S/N   =   3). The proposed immunosensor also has been employed to determine AFP in human serum with satisfactory results. These excellent properties make the AuNPs-PEDOT/PB-rGO nanocomposite an ideal interface for efficient biomarkers detection.

A reversible fluorescence nanoswitch based on dynamic covalent B–O bonds using functional carbon quantum dots and its application for α-glucosidase activity monitoring

Hang Ao,Hui Feng,Xiaolu Huang,Meizhi Zhao,Zhaosheng Qian

Dynamic covalent B–O bonds are introduced to the design of a reversible fluorescence nanoswitch in response to the external stimulus of pH. This nanoswitch is based on a phenylboronic acid functionalized carbon quantum dot (PBA–CQD) nanoprobe, and constructed with reference to the two facts that the PBA–CQD probe can bind to p-nitrophenol to form a non-fluorescent conjugate via B–O bonds, and that the making and breaking of the B–O bonds between them can be controlled by pH changes. Excellent reversibility of this nanoswitch is illustrated by switching of the pH from 4 to 8. The reaction between the PBA–CQD nanoprobe and the p-nitrophenol resulting in switching off the fluorescence is further utilized to design a general detection strategy for enzyme activity when substrates that can generate p-nitrophenol through enzymatic reactions are chosen. The feasibility of the detection strategy is qualitatively assessed using α-glucosidase and β-galactosidase, and its practicability to quantitatively monitor enzyme activity is also demonstrated by taking α-glucosidase as an example. The detection limit of this method can be as low as 0.33 U L−1, which is much lower than those reported previously and is sufficiently low to be capable of α-glucosidase level detection in practical human samples. This study demonstrates excellent usability of dynamic covalent B–O bonds in the design of reversible switches and in the general detection of enzyme activity, and provides a sensitive, real-time assay for α-glucosidase based on carbon quantum dots.

De novo synthesis of α-Alk-β-CD: An organic–inorganic hybrid chiral stationary phase for enhanced enantioseparation efficiency and its recognition mechanism research

Jianbin Zhang,Qiufang Bai,Mei Han,Xizhe Sun,Feixue Zhou,Xin Fang,Yuran Shi,Hongna Wang,Yaowen Zhang,Linwei Li,Linlin Fang

Herein, two highly stable β -CD and α-Alkenyl- β -CD ( α -Alk- β -CD) monolithic columns were fabricated by copolymerizing β -CD and α -Alk- β -CD with GMA onto the pretreated capillary by a simple one-pot strategy. 1 H NMR, SEM, FT-IR, TGA and BET surface area analyses were applied to characterize the prepared monolithic columns. The monoliths were evaluated on the enantioseparations of antibiotic drugs, antihistamine drugs, anticholinergic agents, antifungal drugs and pesticides. In contrast to the native β -CD monolith, the derived α -Alk- β -CD reveals significantly improved enantiodiscrimination performance for the analytes especially for pesticides. Through run-to-run (n = 6), day-to-day (n = 9), and column-to-column (n = 9) investigations, the RSDs values were all lower than 3.72 %. Molecular simulation reveled that the chiral recognition between α -Alk- β -CD and chiral drugs was an exothermic process mainly governed by interaction hydrogen bindings, resulting in different binding strength between a pair of isomers compounds and α -Alkenyl- β -CD, and then leading to different migration and finally achieving effective chiral separation.

Identification of procyanidins as α-glucosidase inhibitors, pancreatic lipase inhibitors, and antioxidants from the bark of Cinnamomum cassia by multi-bioactivity-labeled molecular networking

Jun Dai,Zihan Liu,Lei Ma,Chunliu Yang,Ligai Bai,Dandan Han,Qi Song,Hongyuan Yan,Zhiqiang Wang

This study examined the suppressive effects of 16 selected plant-based foods on α-glucosidase and pancreatic lipase and their antioxidant properties. Among these, the bark of Cinnamomum cassia (Cinnamon, WLN-FM 15) showed the highest inhibitory activity against α-glucosidase and the highest antioxidant activity. Additionally, WLN-FM 15 showed promising results in the other tests. To further identify the bioactive constituents of WLN-FM 15, a multi-bioactivity-labeled molecular networking approach was used through a combination of GNPS-based molecular networking, DPPH-HPLC, and affinity-based ultrafiltration-HPLC. A total of nine procyanidins were identified as antioxidants and inhibitors of α-glucosidase and pancreatic lipase in WLN-FM 15. Subsequently, procyanidins A1, A2, B1, and C1 were isolated, and their efficacy was confirmed through functional assays. In summary, WLN-FM 15 has the potential to serve as a functional food ingredient with the procyanidins as its bioactive constituents. These results also suggest that the multi-bioactivity-labeled molecular networking approach is reliable for identifying bioactive constituents in plant-based foods.

Optimization of subcritical water extraction, UPLC–triple–TOF–MS/MS analysis, antioxidant and α-glucosidase inhibitory activities of anthocyanins from Nitraria sibirica Pall. fruits

Lichengcheng Ren,Qi Dong,Zhenhua Liu,Yue Wang,Nixia Tan,Honglun Wang,Na Hu

This study aimed to optimize subcritical water extraction process, characterize chemical composition and investigate the biological activities of Nitraria sibirica Pall. (NSP) anthocyanin. Overall, the optimization was achieved under following conditions: extraction temperature 140 °C, extraction time 45 min and flow rate 7 mL/min with the extraction yield of 1.075 mg/g. 3 cyanidin, 3 petunidin, 1 delphinidin and 1 pelargonidin compounds were identified in the anthocyanic extract from NSP via UPLC–Triple–TOF–MS/MS. NSP anthocyanin exhibited better DPPH free-radical scavenging activity than ascorbic acid. It displayed superior α-glucosidase inhibition activity, which was ∼14 times higher than that of acarbose. Moreover, enzyme kinetics results indicated that NSP anthocyanin behaved as a reversible, mixed-type inhibitor. Molecular docking and molecular dynamics simulation results revealed that NSP anthocyanin interacted with α-glucosidase mainly via van der Waals forces, hydrogen bond and possessed fairly stable configuration. Therefore, NSP anthocyanin is a promising α-glucosidase inhibitor for diabetes mellitus.

An unconventional separation method of α-Terpineol from its isomer 1,8-Cineole via in situ-association formation of deep eutectic solvent and machine learning

Yingjie Luo,Junjie Qiu,Qiwei Xu,Jing Wei,Hang Song,Beibei Guo,Xuesong Liu,Yong Chen,Tengfei Xu

α-Terpineol and 1,8-cineole are two important compounds in essential oils. This study developed an efficient method to recover α-terpineol from model oil (MO) based on association extraction by in situ formations of deep eutectic solvent (DES) between α-terpineol and some quaternary ammonium salts (QASs) by hydrogen-bond (HB) interaction. Such interaction could be broken almost completely by the introduction of water, due to the stronger HB interaction between water and QASs, which could release α-terpineol by liquid-liquid separation and save the organic solvents consumption. QASs were screened by gaussian energy calculation and experimental verification. Subsequently, the effect of physicochemical properties of the quaternary ammonium salts on the weak interaction between QASs and α-Terpineol was also screened using random forests model. Tetrabutylammonium chloride (TBAC) was proved to form DES with α-terpineol but not with 1,8-cineole, which was proved by FT-IR and 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy. After response surface methodology (RSM) and Genetic Algorithm-Back Propagation (GA-BP) neural network optimization, the distribution ratio and selectivity of α-terpineol to 1,8-cineole could reach a high value of 29.6 and 42.2. The α-terpineol could achieve a purity up to 99.6% with a recovery of 88.8% by the two-step back-extractions using n -hexane and water. Furthermore, camphor leaf essential oil was used to demonstrate the reliability of the method for further application. In this separation process, all reagents including organic salt, n -hexane and water could be recovered and reused. It provides an alternative and promising method for the economical and green treatment of essential oils.

Investigation into the energy storage behaviour of layered α-V2O5 as a pseudo-capacitive electrode using operando Raman spectroscopy and a quartz crystal microbalance

Minghai Yao,Peng Wu,Shuang Cheng,Lufeng Yang,Yuanyuan Zhu,Mengkun Wang,Haowei Luo,Bangfen Wang,Daiqi Ye,Meilin Liu

α-V2O5 nanowires with a layered structure have been fabricated through a two-step procedure. When measured as a pseudo-capacitive electrode with a three-electrode configuration in 1 M Na2SO4 aqueous solutions, α-V2O5 exhibits ideal capacitive characteristics with a specific capacitance of ∼238 F g−1 at a high current of 2 A g−1, but poor cycling stability with a continuous drop in the first 2000 cycles before it is maintained. To find possible solutions towards this problem, the energy storage behavior of the α-V2O5 electrode has been carefully investigated. In situ Raman analysis suggests that it is electrolytic hydrated cations [Na(H2O)n]+ rather than anions (SO42−) that are involved in the energy storage process through reversible adsorption/desorption on the surface or intercalation/deintercalation at the interlayer of the (001) planes accompanied by interlayer spacing expansion/contraction. Moreover, the electrochemical quartz crystal microbalance results indicate that, besides a reversible mass change, there is a continuous mass loss that may originate from slow dissolution of V2O5, which should bear the main responsibility for the poor stability (initial dramatic drop). Hence, how to inhibit dissolution, such as by coating or adding additives in the electrolyte, is found to be the key approach to improve the stability of V2O5 based electrodes.

The influence of hydrogen bonding on the structure of organic–inorganic hybrid catalysts and its application in the solvent-free epoxidation of α-olefins

Hong-Bin Ju,Li-Zhi Zhang,De-Bao Li,Tao Geng,Ya-Jie Jiang,Ya-Kui Wang

In this study, two types of catalysts were prepared by the combination of gemini quaternary ammonium salt with two distinct species of phosphotungstic acid. Catalysts prepared by the Wells–Dawson type of phosphotungstic acid and Keggin-type phosphotungstic acid both exhibited dual-phase catalytic behavior, demonstrating both heterogeneous and homogeneous catalytic activities. In comparison to the catalyst prepared by the Keggin-type phosphotungstic acid, due to the higher size of Wells–Dawson type of phosphotungstic acid, hydrogen bonding could not effectively affect the catalyst prepared by H6P2W18O62. Subsequently, the influential factors on the catalytic reaction were investigated. Through the utilization of techniques such as XPS, FT-IR, Raman spectra and other characterization methods, two distinct structure and reaction mechanisms for these catalysts were elucidated under the influence of hydrogen bonding.