JOURNAL OF MATERIALS SCIENCE
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2019
·Vol. 54
·期 9
·6853-6866
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IF 3.442
Jin Manman,Guo Zhenmei,Lv Zhiguo
An efficient hybrid mesoporous heterogeneous catalyst system was synthesized via covalently grafting tungsten chelate complex W- N , N ( N , N = (3-triethoxysilylpropyl) [3-(2-pyridyl)-1-pyrazolyl] acetamide, N,N -chelating ligand) in organic moieties (diphenyldichlorosilane, DPHS)-functionalized mesoporous silica SBA-15 or pure SBA-15. Characterization of synthesized materials via N 2 sorption, XRD, TEM, UV–Vis DRS, 29 Si MAS NMR, element analysis, and FT-IR indicated that W- N , N was successfully anchored and highly dispersed in the mesochannels of SBA-15 and the mesostructure of SBA-15 was maintained during the grafting course. The synthesized hybrid catalysts were highly active and authentically heterogeneous in triphasic oxidation reaction of cyclopentene (CPE) with H 2 O 2 . W, N - N immobilized on functionalized SBA-15 with DPHS moieties (W- N , N -DPHS-SBA-15) showed better catalytic properties (activity and stability) than its unmodified counterpart W- N , N -SBA-15 catalyst. Besides, possible catalytic reaction route for CPE oxidation with H 2 O 2 over W- N , N -DPHS-SBA-15 catalyst was proposed. The amphiphilic mesochannels of W- N , N -DPHS-SBA-15 provided suitable accommodation for both hydrophilic H 2 O 2 and hydrophobic CPE molecules and acted as nanoreactors for CPE/H 2 O 2 /solid triphase reaction.
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高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 2
·638-643
·
IF 2.372
He Wei-Xun,Xing Xiu,Yang Zeng-Jie,Yu Yuan,Wang Na,Yu Xiao-Qi
A facile and green method catalyzed by α-amylase has been developed for the synthesis of highly substituted indoloquinolizines using tryptamines, β-ketoesters and α,β-unsaturated aldehydes. The reaction afforded a variety of products in moderate to good yields and with high diastereoselectivity. The densely functionalized products were obtained in a single synthetic operation under mild conditions. Graphical Abstract
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高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 5
·1197-1210
·
IF 2.372
Wang Lina,Guo Tong,Sun Sen,Wang Yan,Chen Xiaoling,Zhang Kangning,Zhang Dongxia,Xue Zhonghua,Zhou Xibin
Abstract The electrocatalytic activity of transition metal dichalcogenides (TMDs) is largely dependent on the exposed massive active sites and electrical conductivity of the catalysts. In this work, a tree-like nanocomposite (NiS 2 /MoS 2 -RGO) which is composed of bimetal sulfide (NiS 2 /MoS 2 ) nanocomposites uniformly anchored on the surface of reduced graphene oxide (RGO) was successfully synthesized. As a catalytic material for the hydrogen evolution reaction (HER), the NiS 2 /MoS 2 -RGO composites exhibit significantly enhanced electrocatalytic activity and impressive long-term stability for the hydrogen evolution reaction over a wide pH range. The tree-like NiS 2 /MoS 2 -RGO nanocomposites afford a current density (η 10 ) of 10 mA/cm 2 at small overpotentials of 172, 144 and 229 mV, and have a small Tafel slope of 51, 82 and 103 mV/dec in acidic, alkaline and neutral solution, respectively. Further studies reveal that the effective activities benefit from the abundant active edge sites and defects of NiS 2 /MoS 2 nanocomposites and the excellent conductivity of RGO. Graphical Abstract
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高影响因子
Metabolomics
·
2019
·Vol. 15
·期 3
·1-12
·
IF 3.167
Yuan Honglun,Xu Yong,Chen Yaozhong,Zhan Yangyang,Wei Xuetuan,Li Lu,Wang Dong,He Penghui,Li Shengqing,Chen Shouwen
Introduction Acetoin serves as a high value-added platform with a broad range of applications, and can be effectively produced by Bacillus licheniformis . However, its toxicity to the producing strain hinders the higher acetoin production, and current knowledge about the acetoin resistance mechanisms of B. licheniformis is quite limited. Objectives To comprehensively investigate the metabolic changes in B. licheniformis under acetoin stress. Methods We used gas chromatography-mass spectrometry based untargeted metabolomics approach to measure the metabolic profiles of B. licheniformis under 20, 40 and 80 g/L acetoin stress. Transcriptional analysis was conducted to verify the metabolomics results. Results A total of 119 metabolites were identified in our experiment. The metabolic responses of B. licheniformis to acetoin stress were as follows: (i) pentose phosphate pathway and tricarboxylic acid (TCA) cycle were negatively affected by acetoin stress. In turn, glyoxylate cycle was activated to supply malic acid. (ii) Acetoin stress induced the accumulation of serine, valine, leucine and protective osmolytes (glycine and proline). (iii) Acetoin stress induced a higher saturated fatty acid ratio, which indicated a lower fluidity of cell membrane that could inhibit the entry of acetoin into cytoplasm. (iv) Synthesis of phosphatidylserine was enhanced, and phosphatidylethanolamine content was probably increased under acetoin stress. Conclusions This study revealed the metabolic perturbations of B. licheniformis to acetoin stress. In response to acetoin stress, glyoxylate cycle was activated, protective osmolytes were accumulated, saturated fatty acid ratio was elevated and synthesis of phosphatidylserine was enhanced in B. licheniformis .
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 10
·7702-7718
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IF 3.442
Li Wei,Wu Gang,Tan Jinhui,Zhu Yuntao,Yu Xufeng,Lei Yang,Sun Gang,You Bo
A novel robust self-healing superhydrophobic F-SiO 2 /Fe 3 O 4 /EP(epoxy)/PCL nanocomposite film was fabricated through a facile two-step method including resin spraying and NPs perpendicular gradient deposition. Specially, the epoxy/polycaprolactone (EP/PCL) mixed resin matrix was prepared through a spraying process and the functioned silica/magnetic iron oxide (F-SiO 2 /Fe 3 O 4 ) nanoparticles were then deposited on the resin matrix by gradient distribution under gravity and solvent evaporation. The THF/ethanol mixture solvent which acted as film microstructure-directing agent guided the F-SiO 2 /Fe 3 O 4 nanoparticles gradient distribution in the nanocomposite films. The results showed that the cutting cracks on the nanocomposite film could be rapidly self-healed and the film would maintain its superhydrophobicity after irradiation by near-infrared light. The nanocomposite films, especially the F-SiO 2 (8.5wt%)/Fe 3 O 4 (1.0wt%)/EP/PCL nanocomposite film, showed high resistant properties on abrasion, corrosive liquids and UV irradiation. The recovery mechanism of the nanocomposite films was also investigated.
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Scientific Reports
·
2019
·Vol. 9
·期 1
·1-11
·
IF 4.011
Geng Qianqian,Li Tian,Wang Xin,Chu Weijing,Cai Mengling,Xie Jingchan,Ni Hanwen
In this work, the inclusion complexes of hydrophobic herbicide bensulfuron-methyl (BSM) with β-cyclodextrin (β-CD) and (2-hydroxypropyl)-β-CD (2-HP-β-CD) were prepared and characterized. Phase solubility study showed that both β-CD and 2-HP-β-CD increased the solubility of BSM. Three-dimensional structures of the inclusion complexes were simulated by the molecular docking method. The docking results indicated that guest BSM could enter into the cavities of host CDs, folded, and centrally aligned inside the inclusion complexes. The benzene ring of the guest molecule was close to the wide rim of the host molecules; the pyrimidine ring and side chains of the guest molecule were oriented toward the narrow rim of the host molecule. The inclusion complexes were successfully prepared by the coprecipitation method. The physiochemical characterization data of 1 H NMR, FT-IR, XRD, and DSC showed that the guest and host molecules were well included. BSM had lower soil adsorption and higher herbicidal activity in the complexation form with β-CD or 2-HP-β-CD than in the pure form. The present study provides an approach to develop a novel CDs-based formulation for hydrophobic herbicides.
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PubMed
高影响因子
Food Analytical Methods
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2019
·Vol. 12
·期 7
·1594-1603
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IF 2.413
Weng Rui,Sun Lingshun,Jiang Liping,Li Na,Ruan Guihua,Li Jianping,Du Fuyou
In this study, electrospun graphene oxide–doped poly(acrylonitrile- co -maleic acid) nanofibers (E-spun-GO-PANCMA-NFs) were fabricated and investigated as novel adsorbent for solid phase extraction (SPE) of tetracycline antibiotics (TCs) in chicken samples. The as-synthesized E-spun-GO/PANCMA-NFs were characterized and then used as SPE adsorbent to combine with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) for simultaneous determination of four TCs (tetracycline, oxytetracycline, chlorotetracycline, and doxycycline). The experimental parameters affecting the analytical performance of this method, including sample pH, ionic strength, solvent type, volume and time desorption, and sample volume, were optimized. Under the optimized conditions, the proposed method provided good linearity from 5 to 500 ng/mL, with correlation coefficients higher than 0.9990, limits of detection from 20.4 to 44.8 μg/kg, and limits of quantification from 69.7 to 115.5 μg/kg. The intra- and inter-day RSDs were less than 5%. The recoveries of TCs spiked in chicken muscle samples were from 84.7 to 106.3% with RSDs in the range of 0.4–4.5%. Finally, the proposed E-spun-GO/PANCMA-NF-based SPE-HPLC-FLD method has been successfully applied to the analysis of TCs in chicken tissue samples, and thus offered a great prospect for TC analysis mainly in the applications of food quality and safety protection.
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JOURNAL OF POLYMER RESEARCH
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2019
·Vol. 26
·期 5
·1-12
·
IF 1.53
Chen Dan,Gong Feirong,Han Xiaoxiong,Chi Lili,Sun Jing,Shen Yaling
Conventional self-assembled polymeric micelles typically lose their loaded drugs after systemic administration. To resolve this issue, the aim of the present study was to develop a novel polymer, methoxy-poly (ethylene glycol)-block-poly ( d , l -lactic acid) grafted with four lipoic acids (mPEG-PLA-(LA) 4 ), to prepare curcumin-loaded core cross-linked polymeric micelles (CCM). Nitrogen and alkalescent buffer (pH 8.5) were beneficial for cross-linking, and the cross-linking was nearly complete within 30 min. The micelle preparation parameters were optimized through both a single-factor experiment and orthogonality test. The choice of cryoprotector had the most important effect on micelle solution reconstruction and almost challenged our perceptions about cryoprotector. In addition the drug loading capacity greatly affected the stability of micelles. Moreover, a method for determining the cross-linking density was established, and the result of gel permeation chromatography indirectly demonstrated that dozens of polymers had successfully formed CCM. The CCM significantly enhanced stability under non-reductive conditions and could be reversibly broken in a reductive environment. Curcumin-loaded CCM also showed glutathione-response cytotoxicity to cancer cells. Overall, this fundamental study suggests CCM as a potential carrier for achieving improved controlled drug delivery.
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高影响因子
CELLULOSE
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2019
·Vol. 26
·期 5
·3285-3297
·
IF 3.917
Gao Hejun,Du Jia,Liao Yunwen
Abstract A novel biological magnetic adsorbent was successfully constituted with sugarcane bagasse (SCB), polyetherimide (PEI) and Fe 3 O 4 . The physicochemical properties of the adsorbent (Fe 3 O 4 @PEI/SCB) were investigated by SEM, BET, VSM, XRD, TGA, FT-IR, XPS, TEM and UV–Vis. The adsorption capacity was measured using Cr(VI) and orange II as adsorbates. The effects of initial pH, dosage, contact time, and ionic strength on the adsorption capacity were investigated in detail. Fe 3 O 4 @PEI/SCB is a mesoporous material and the mass ratio of Fe 3 O 4 :PEI:SCB is about 5:2:15. Adsorption capacity could reach 182.28 mg/g and 1893.57 mg/g for Cr(VI) and orange II at room temperature, respectively. Fe 3 O 4 @PEI/SCB is a green and economical material, which is very easily regenerated, reused, and separated in the adsorption. The most important factor is the ionic strength and major adsorption interaction was electrostatic in this work. Graphical abstract
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高影响因子
BULLETIN OF MATERIALS SCIENCE
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2019
·Vol. 42
·期 1
·1-7
·
IF 1.264
Hassan Mohamed,Ran Xiaoku,Yuan Ying,Luan Xiaoning,Dou De-Qiang
Ginsenoside transformation has received significant attention from scientists. The main objective of this study is to use immobilized enzymes in ginsenoside transformation. Factors affecting immobilization process were studied; carrageenan beads treated with polyethyleneimine and then activated using glutaraldehyde (GA) were used for snailase enzyme immobilization. The functionalized gel beads were characterized using Fourier transform infrared spectroscopy to verify the modification process. Furthermore, the optimum conditions for biotransformation of ginsenoside were also deliberated and showed that optimum biotransformation pH is 4.5 and 5–5.5 and temperature 50 and \(60^{\circ }\hbox {C}\) for free and immobilized snailase, respectively. Michaelis constants, \(K_{\mathrm{m}}\) and \(V_{\max }\) , were also studied. The immobilized enzyme retains 96% of its initial activity after being used 10 consecutive times. The results clearly suggested that ginsenoside transformation was performed using immobilized snailase; this process can reduce the transformation cost as the enzyme can be reused many times.
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高影响因子
MICROCHIMICA ACTA
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2019
·Vol. 186
·期 3
·1-9
·
IF 5.479
Zhao Pengcheng,Chen Chao,Ni Meijun,Peng Longqi,Li Chunyan,Xie Yixi,Fei Junjie
An electrochemical dopamine sensor with a temperature-controlled switch was constructed by using a mixture of thermo-sensitive block copolymers (type tBA-PDEA-tBA), graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs). If the temperature is below 26 °C, the polymer on the glassy carbon electrode (GCE) is stretched, the distance between the MWCNTs is large, and the charge transfer resistance (R ct ) of the composite also is large. In the presence of dopamine, the electron transfer at the electrode is strongly retarded and in the “off” state. At above 38 °C, the polymer is shrunk and the R ct is much smaller. The presence of dopamine results in a rapid electron transfer at the GCE, and this is referred to as the “on” state. At temperatures between 26 and 38 °C, the polymer shrinks slightly and has a “spring-like” state. There is a linear relationship between the response current (typically measured at a potential as low as 0.16 V vs. Ag/AgCl) and temperature. The response to dopamine is linear in the 0.06 to 4.2 μM and 4.2 to 18.2 μM concentration range, and the detection limit is 42 nM. Conceivably, this approach provides a novel approach towards the design of electrochemical sensors based on the use of thermo-sensitive polymers.
Schematic presentation of reversible and temperature-controlled electrochemical response of dopamine on the thermo-sensitive block copolymers (tBA-PDEA-tBA) / multi-walled carbon nanotubes (MWCNTs) / graphene oxide (GO) / glassy carbon electrode (GCE).
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高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
·
2019
·Vol. 29
·期 4
·1192-1197
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IF 1.637
Zhao YingRui,Yang Chao,Zhang HongYan,Qiang Gen,Fan HuiLing
Two kinds of ZnO/SiO 2 composite (labled as SZ-1 and SZ-2) were synthesized by sol–gel method and characterized by X-ray diffraction (XRD) patterns, XPS (X-ray photoelectron spectroscopy) spectra and Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectra. Water adsorption on the prepared sample was studied by in situ DRIFT. The as-synthesized SZ-1 and SZ-2 sample have different surface property due to the various aging methods in the sample preparation processes, thus showing different results of water adsorption. The adsorption sites (Si atom in Si–O–Si bond) on the surface of SZ-2 for water molecule are occupied by the –OCH 3 group and the hydrophilicity of SZ-2 is weaker, in comparison to SZ-1, which inhibits the formation of water film and ultimately decreases desulfurization performance of SZ-2. So, the desulfurization performance can be changed by altering the hydrophilicity of sorbent.
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