APPLIED CATALYSIS A-GENERAL
·
2018
·
IF 4.521
Zihao Zhang,Changxue Wang,Xin Gou,Hao Chen,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
A series of Cu-based catalysts with different supports were synthesized and studied for the in situ hydrogenation of 5-hydroxymethylfurfural (5-HMF) to dimethylfuran (DMF) using methanol as an economical hydrogen donor. The structures and properties of the four catalysts (Cu/Al 2 O 3 , Cu/ZnO, Cu/ZrO 2 , and Cu/CeO 2 ) were characterized using X-ray diffraction (XRD), temperature-programmed reduction (H 2 -TPR), and temperature-programmed desorption of ammonia (NH 3 -TPD). The experimental results showed that the use of different supports for the Cu-based catalysts significantly influenced their activity for both H 2 production from methanol and hydrogenation of 5-HMF. The catalyst Cu/Al 2 O 3 showed the best catalytic activity, which can be attributed to the highest activity for the in situ H 2 production from methanol, smallest Cu crystallite size, and strongest acidity. The effects of the substrate concentration, catalyst loading, and reaction temperature and time on the in situ hydrogenation of 5-HMF were systematically investigated to determine the optimum reaction conditions.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Fuxiang Feng,Li Wang,Xiangwen Zhang,Qingfa Wang
HZSM-5 zeolite has been extensively utilized in the petrochemical and fine chemical industry owing to its excellent isomerization/cracking activity and hydrothermal stability. However, it still remains a great challenge for ZSM-5-supported catalysts to upgrade vegetable oils to aviation-fuel-range-alkanes (AFRAs). Herein, an efficient Ni/ZSM-5 catalyst composed of self-pillared (SP) nanosheets along with high external acid fraction and short characteristic diffusion length was synthesized and employed for this reaction. This SP Ni/ZSM-5 nanosheet catalyst shows high deoxygenation, cracking/isomerization activity, and excellent catalytic stability for upgrading oleic acid to AFRAs, which is attributed to the SP nanosheet structure and reasonable acid distribution. Last, a high AFRA yield of 40% with an iso/n-alkanes ratio of 1.8 was achieved.
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BIOLOGICAL & PHARMACEUTICAL BULLETIN
·
2019
·Vol. 42
·期 6
·886-891
·
IF 1.54
Yangbiao He,Xujun Lang,Dong Cheng,Zhihao Yang
Previous studies implicated the mammalian target of rapamycin (mTOR)/hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway in renal fibrosis and found that curcumin could suppress the expression of mTOR. Therefore, the aim of the present study was to investigate the therapeutic effects of curcumin against chronic renal failure (CRF) in a rat model induced by 5/6 nephrectomy through inhibition of mTOR/HIF-1α/VEGF signaling. A total of 70 male Sprague–Dawley rats were divided into seven groups: a sham group, a CRF group, and five treatment groups. Except for the sham rats, all rats underwent 5/6 nephrectomy to induce CRF. The 5/6 nephrectomized rats received treatment with curcumin vehicle, everolimus vehicle, curcumin, everolimus, or the combination of curcumin and everolimus. Everolimus, a specific inhibitor of mTOR, was used as a positive control. At the end of treatment, blood biochemical indexes, proteinuria and the kidney index were detected. Moreover, histological change was examined by hematoxylin and eosin staining, and protein expression levels were detected by Western blotting. The blood biochemical indexes, proteinuria, and kidney index were increased in the CRF group as compared to the sham group, which was accompanied by marked activation of the mTOR/HIF-1α/VEGF pathway. However, curcumin, as well as everolimus, restored or ameliorated these changes. These results indicate that activation of the mTOR/HIF-1α/VEGF signaling pathway plays an important role in the occurrence and development of CRF, and that curcumin has renoprotective effects by blocking activation of this pathway.
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高影响因子
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
·
2019
·Vol. 57
·期 11
·713-721
·
IF 2.596
Qiao Wang,Lefan Li,Zongjin Li,Siyao Guo,Guoxing Sun
It remains challenging to satisfy the combined performances for hydrogels with excellent mechanical behavior, high deformability, and super recoverability under harsh environmental conditions. In this study, we first established a strong polymer network via the crosslinking of polymer chains on the surfaces of sub-5-nm calcium hydroxide nanospherulites in ethylene glycol solvent. The organic gel expressed excellent mechanical properties such as a recoverable compressive engineering stress of 249 MPa and an elongation stress of 402 KPa, which was attributed to the uniform nanosized crosslinking structure as characterized by SEM. Moreover, the nonvolatile solvent remained in the gel, meaning that the sample can resist a wide temperature range of −56 to 100 °C without losing the elastic properties. This novel organic gel could provide promising routes to develop the ideal elastic carriers for wearable devices, smart skin sensors, and damping materials. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57 , 713–721
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JOURNAL OF CHROMATOGRAPHY A
·
2019
·
IF 3.858
Chunjian Wu,Li Wang,He Li,Shujuan Yu
The presence of potential carcinogen 4(5)-Methylimidazole (4-MeI) in foods causes much concern, stressing the need of a sensitive determination means. Here, we proposed a high-sensitivity method to determine 4-MeI in biscuits using dansyl chloride derivatization and disperse liquid-liquid micro-extraction (DLLME) followed by a liquid chromatography-ion trap mass spectrometry (LC-IT-MS) analysis. This developed method was subsequently compared to the solid phase extraction combining with liquid chromatography-triple quadrupole mass spectrometry (SPE-LC-QqQ-MS) method. The optimized derivatization conditions were 30 °C and 10 min. Results suggested that the column retention time (RT) was significantly extended, and the MS signal response of 4-MeI-dansyl derivative was also amplified. The developed DLLME-LC-IT-MS method in 4-MeI determination provided satisfactory linearity in a range of 0.5–300 ng/mL (R 2 > 0.9991), inter-day accuracy (87-102%) and precision (%RSD ≤ 13.6%) with the quantification limit of 0.2 ng/mL, which obtained similar results comparing to the conventional SPE-LC-QqQ-MS method.
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RADIOCHIMICA ACTA
·
2019
·Vol. 108
·期 4
·239-247
·
IF 1.339
Quan Gan,Yimin Cai,Kuirong Fu,Lihua Yuan,Wen Feng
The extraction of U(VI) from aqueous nitric acid solutions with pillar[5]arene-based phosphine oxide (L) and [C8mim][NTf 2 ] ionic liquid dissolved in 1,2-dichloroethane was explored. A great positive impact in this system was observed. The effect of IL concentration in the organic phase and HNO 3 concentration in the aqueous phase is considered. The distribution ratios of U(VI) were significantly enhanced upon adding a small amount of ionic liquid as compared with organic diluent. The extraction system was also examined for its ability towards extraction of lanthanides and Th 4+ . The results revealed higher separation factors towards UO 2 2+ over Th 4+ in the presence of ionic liquid compared with organic diluent. Other factors such as C 8 mim + and NTf 2 − have also been considered. This extraction system has shorter equilibrium time as compared with in IL diluent. Stripping experiments showed almost quantitative back extraction of UO 2 2+ within two stages. With high selectivity towards UO 2 2+ and efficient back extraction, this new POP5A-ionic liquid-organic diluent system shows promise for future application of uranium recovery.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2018
·
IF 3.468
Hao Chen,Hao Cheng,Feng Zhou,Kequan Chen,Kai Qiao,Xiuyang Lu,Pingkai Ouyang,Jie Fu
The synthesis of highly selective catalysts for the catalytic fast pyrolysis (CFP) of biomass into valuable aromatics remains a challenge. This report describes the synthesis of hierarchical ZSM-5 catalysts by the NaOH desilication of conventional HZSM-5 for the CFP of rice straw to aromatics in a Tandem μ-reactor system coupled directly to a GC/MS equipped with FID and TCD. Catalysts were treated with a mild HCl wash and metal loading to increase the catalytic activity and reduce the deactivation. The effects of acidity, mesoporosity and incorporation of metals on the production of aromatics were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption and desorption (N 2 -BET) and temperature-programmed desorption of NH 3 (NH 3 -TPD). The highest total acidity, especially the strong acidity, of the hierarchical ZSM-5 treated by 0.2 and 0.4 NaOH followed by HCl washing (AHZ-0.2 and AHZ-0.4) gave the highest yields of aromatics. Suitable mesopores introduced by alkali treatment enhanced mass transfer of reactants, increasing the yield of aromatics. Finally, the loading of a suitable amount of Ni and Cu produced more aromatics than standard HZSM-5 due to the improved decarboxylation/decarbonylation reactions leading to higher yields of olefins.
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 4
·1-8
·
IF 5.705
Liu Xiaojie,Lin Bixia,Yu Ying,Cao Yujuan,Guo Manli
A multifunctional fluorescent probe is synthesized for the determination of adenosine 5′-triphosphate (ATP). The 6-carboxyfluorescein-labeled aptamer (FAM-aptamer) was bound to the surface of magnetite nanoparticles coated with polydopamine (Fe 3 O 4 @PDA) by π-π stacking interaction to form the multifunctional probe. The probe has three functions including recognition, magnetic separation, and yielding a fluorescent signal. In the presence of ATP, FAM-aptamer on the surface of the probe binds to ATP and returns to the solution. Thus, the fluorescence of the supernatant is enhanced and can be related to the concentration of ATP. Fluorescence intensities were measured at excitation/emission wavelengths of 494/526 nm. Response is linear in the 0.1–100 μM ATP concentration range, and the detection limit is 89 nM. The probe was applied to the quantitation of ATP in spiked human urine and serum samples, with recoveries ranging between 94.8 and 102%.
A multifunctional fluorescent probe based on the use of FAM-aptamer and Fe 3 O 4 @PDA is described for the determination of ATP in spiked human urine and serum samples. FAM-aptamer: 6-carboxyfluorescein-labeled aptamer; Fe 3 O 4 @PDA: magnetite nanoparticles coated with polydopamine. ATP: adenosine 5′-triphosphate.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2019
·
IF 3.218
Jing Sun,Fang Guo,Qiaofang Shi,Huayu Wu,Yan Sun,Ming Chen,Guowang Diao
In this paper, silver nanoparticles (AgNPs) modified by carboxylated pillar[5]arene (CP5) were anchored on graphene oxide (GO) by π-π stacking interaction and hydrogen bond between CP5 molecules and GO. The obtained hybrid nanomaterials CP5-AgNPs/GO were characterized by ultraviolet-visible adsorption spectrometer, Fourier transform infrared adsorption spectrometer, and transmission electron microscopy . Testing of various electrochemical techniques displays that the CP5-AgNPs/GO modified glass carbon electrodes (GCE) show good electrocatalytic property , molecular recognition and enrichment performance toward paraquat (PQ) and exhibit high current response. Compared with other modified electrodes , such as GO/GCE and CP5/GO/GCE, CP5-AgNPs/GO/GCE shows an outstanding electrochemical response for PQ with high sensitivity of 78.8 mA mmol −1 L cm −2 . The analytical curves for PQ obtained by differential pulse voltammetry are linear in the range from 1.0 × 10 −8 to 1.0 × 10 −5 M and from 2.0 × 10 −5 to 7.0 × 10 −5 M. The limit of detection is 1.0 × 10 −8 M (S/N = 3). This excellent performance is ascribed to the synergic electrocatalytic effect of AgNPs and GO, and the host-guest recognition of CP5 for PQ.
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Nanoscale Research Letters
·
2017
·Vol. 12
·期 1
·1-11
·
IF 2.833
Zhang Zheng,Chen Yunsheng,Ding Jiayue,Zhang Chunlei,Zhang Amin,He Dannong,Zhang Yixin
Biocompatible 5-aminolevulinic acid/Au nanoparticle-loaded ethosomal vesicle (A/A-ES) is prepared via ultrasonication for synergistic transdermal photodynamic/photothermal therapy (PDT/PTT) of hypertrophic scar (HS). Utilizing ultrasonication, Au nanoparticles (AuNPs) are synthesized and simultaneously loaded in ethosomal vesicles (ES) without any toxic agents, and 5-aminolevulinic acid (ALA) is also loaded in ES with 20% of the entrapment efficiency (EE). The prepared A/A-ES displays strong absorbance in 600-650 nm due to the plasmonic coupling effect between neighboring AuNPs in the same A/A-ES, which can simultaneously stimulate A/A-ES to produce heat and enhance quantum yields of reactive oxygen species (ROS) by using 632 nm laser. In vitro transdermal penetrability study demonstrates that A/A-ES acts as a highly efficient drug carrier to enhance both ALA and AuNPs penetration into HS tissue . Taking human hypertrophic scar fibroblasts (HSF) as therapeutic targets, synergistic PDT/PTT of HS indicates that A/A-ES could enhance quantum yields of ROS by photothermal effect and localized surface plasmon resonance (LSPR) of AuNPs, resulting in a high level of apoptosis or necrosis. In a word, the prepared A/A-ES shows a better synergistic PDT/PTT efficiency for HSF than the individual PDT and PTT, encouraging perspective for treatment of HS.
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CATALYSIS COMMUNICATIONS
·
2012
·
IF 2.986
Linping Sun,Xinwen Guo,Guang Xiong,Xiangsheng Wang
The ethylation of coking benzene with ethanol over nano-sized ZSM-5 zeolites modified with Y 2 O 3 , La 2 O 3 and CeO 2 was investigated in a fixed-bed reactor. Nano-sized ZSM-5 zeolite modified with Y 2 O 3 was more stable than the other two samples during the reaction. The results from NH 3 -TPD, Py-IR, and TG-DTA show that the strong Brønsted acid sites were eliminated, consequently suppressing coke deposits during the reaction. Combined with the results from 1 H NMR and 129 Xe NMR spectra, it is concluded that the hydrated Yttrium ions with small size reached deep location in zeolite channel.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2024
·
IF 5.8
Shan Cheng,Yi Fu,Hong Tian,Yi Cheng,Jiawei Wang,Jiang Zhu,Linxi Guo,Xuan Huang
The selectivity and catalytic mechanism of HZSM-5 in the pyrolysis of lignin model compounds at 600 °C were investigated using Py-GC/MS and density functional theory (DFT). The findings indicate that HZSM-5 elevated the relative content of aromatic hydrocarbons in the pyrolysis products of phenol, vanillin, and syringol by 12.3 %, 11.7 %, and 7.5 %, respectively. Meanwhile, the relative content of oxygen-containing products, including aldehydes and acids, was reduced by 15.7–52.0 %. Throughout the pyrolysis of lignin model compounds, various side chain reactions take place, such as dissociation, decarbonylation, isomerization rearrangement, alkylation, and aromatization. The selective catalytic decomposition mechanism of HZSM-5 on oxygen-containing functional groups involves both the physical selection imparted by the pore size structure and the selection of acid sites that form hydrogen bonds with hydroxyl, carbonyl, and methoxy groups. This mechanism was corroborated by DFT calculations, which showed that the energy barriers for the removal of most oxygen-containing functional groups were lowered by 1.7–72.4 kJ/mol. These results provide an in-depth understanding of the catalytic pyrolysis of lignin and pave the way for future research on the high-value utilization of waste lignin.
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