JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 137
·期 20
·48687
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IF 2.188
Xiangyang Chen,Dongfeng Xu,Hua Zhang,Xinxing Feng,Jianping Deng,Kai Pan
A novel halogen-free flame retardant copolyamide 6,6 (FR-PA66) was prepared successfully by in situ polymerizing with adipic acid hexamethylene salt and 2-carboxy ethyl (phenyl) phosphinic acid (CEPPA). The elemental composition and chemical structure of FR-PA66 were characterized by energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer and 13 C Nuclear magnetic resonance spectrometer. The flame retardancy, thermal stability, and morphology of char residues were also investigated by the limiting oxygen index (LOI), UL 94 test, thermogravimetric analysis, and scanning electron microscopy. The results showed that FR-PA66 samples had much better flame retardancy and char formation ability than pure PA66 after the flame retardant modification. The LOI values were increased from 24.0 to 28.0% by adding 6 wt % of CEPPA and all FR-PA66 samples were rated as V-0 rating in UL-94 test. Furthermore, the thermal stability analysis indicated that in situ polymerization with CEPPA effectively decreased the initial decomposition temperature and increased the amount of char residue. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137 , 48687.
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Shuangyu Xiong,Luminita Marin,Lian Duan,Xinjian Cheng
Nitroaromatic compounds, especially 2, 4, 6-trinitrophenol, have strong biological toxicity and explosive risks, so the detection of 2, 4, 6-trinitrophenol exhibit importantly practical and scientific significance. In this work, three fluorescence functionalized chitosan CNS 3 , CNS 4 and CNS 5 were prepared using chitosan as matrix. When 2, 4, 6-trinitrophenol (TNP) and/or p-nitrophenol (4-NP) was present in spot, these fluorescent chitosan sensors produced notable fluorescence quenching. It renders the chitosan sensing ability to detect TNP and 4-NP selectively and sensitively. The sensing mechanism is investigated as well. When introduced electron-rich moieties to the fluorescent chitosan, the sensitive detecting ability could be obtained. Excellent recognition ability could reach as low as 0.28 μM. The fluorescence fictionalization cause slight influence to the gel performance of chitosan.
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BIOTECHNOLOGY LETTERS
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2019
·Vol. 41
·期 10
·1223-1232
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IF 2.154
Zhang Yin-Jun,Chen Chang-Sheng,Liu Hao-Tian,Chen Jia-Lin,Xia Ying,Wu Shi-Jin
Objective To purify an esterase which can selectively hydrolyze ( R,S )-ethyl indoline-2-carboxylate to produce ( S )-indoline-2-carboxylic acid and characterize its enzymatic properties. Results An intracellular esterase from Bacillus aryabhattai B8W22 was isolated and the purified protein was identified as a carboxylesterase by MALDI-TOF mass spectrometry. The enzyme (named BaCE) was 59.03-fold purification determined to be of approximately 35 kDa. Its specific activity was 0.574 U/mL with 20% yield. The enzyme showed maximum activity at pH 8.5 and 30 °C and was stable at 20–30 °C using p NPB as the substrate. The K m , V max , k cat and k cat /K m of the esterase were 0.52 mM, 6.39 μM/min, 26.87 min −1 and 51.67 mM/min, respectively. The esterase demonstrated high enantioselectivity toward ( S )-ethyl indoline-2-carboxylate with 96.55% e.e. p at 44.39% conversion, corresponding to an E value of 133.45. Conclusions In this study, a new esterase BaCE with an apparent molecular mass of 35 kDa was purified to homogeneity for the first time. The esterase from Bacillus aryabhattai B8W22 was isolated with a purification more than 59-fold and a yield of 20% by anion exchange chromatography and hydrophobic interaction chromatography. And its biochemical characterization were described in detail with p NPB as substrate. It displayed high enantioselectivity toward ( S )-ethyl indoline-2-carboxylate. We next plan to highly express esterase BaCE in Escherichia coli , and apply it to industrial production of ( S )-indoline-2-carboxylic acid.
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IET Nanobiotechnology
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2018
·Vol. 12
·期 7
·946-950
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IF 2.059
Zhuanzhuan Zhang,Xianjun Dai
The conditions were optimised for preparing Alginate oligosaccharide (AOS) nanoliposomes, and Caco-2 cell experiments were carried out to examine their antitumour effects. The optimal formulation of AOS nanoliposomes was as follows: a phosphatidylcholine-to-cholesterol ratio of 5.12, AOS concentration of 8.44 mg/mL, Tween 80 concentration of 1.11%, and organic phase to aqueous phase ratio of 5.25. Under the above conditions, the experimental encapsulation efficiency was 65.84%, and the AOS nanoliposomes exhibited a small particle size of 323 nm. After Caco-2 cells were treated with AOS liposomes and AOS for 24 h, AOS nanoliposomes inhibited the growth of Caco-2 cells to a greater extent than AOS at concentrations of 0.0625, 0.125, 0.25, 0.5 and 1 mg/mL ( P < 0.01). LDH leakage exhibited a concentration-dependent increase following treatment with 0.5-1 mg/mL AOS nanoliposomes, and the inhibitory effect of AOS nanoliposomes exhibited a more significant difference than AOS ( P < 0.01). Cells treated with 0.5 mg/mL and 1 mg/mL AOS nanoliposomes displayed a substantial and significant increase in activity compared with AOS ( P < 0.01). Based on these results, AOS nanoliposomes exerted a more significant effect on inhibiting Caco-2 cell proliferation than AOS.
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GREEN CHEMISTRY
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2019
·Vol. 21
·期 3
·606-613
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IF 9.405
Zhenbing Xie,Bingfeng Chen,Haoran Wu,Mingyang Liu,Huizhen Liu,Jianling Zhang,Guanying Yang,Buxing Han
Transformation of biomass or biomass-based feedstocks into fuels or valuable chemicals is of great importance for the sustainable development of our society. Mesoporous Al2O3–ZrO2 with different Al : Zr molar ratios was prepared by the sol–gel method, and Cu–Ni/Al2O3–ZrO2 catalysts were fabricated by the impregnation method. The catalytic performances of the bifunctional catalysts were studied in the selective hydrogenation of levulinic acid (LA) into 2-methyltetrahydrofuran (MTHF). It was demonstrated that both Cu : Ni and Al : Zr ratios affected the selectivity to MTHF significantly. The bimetallic catalysts Cu–Ni/Al2O3–ZrO2 containing 10 wt% Ni and 10 wt% Cu gave 99.8% MTHF selectivity at full conversion of LA when the Al : Zr ratio was 9 : 1. The outstanding catalytic performance of the catalyst is related to the mesoporous structure, the acidic properties of the support and the synergistic effect between Cu and Ni. The catalyst could be reused five times without a considerable loss of catalytic activity and selectivity.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2018
·
IF 3.649
Qingqing Ma,Nan Wang,Guozhu Liu,Li Wang
Pd catalysts on mesoporous silica SBA-15 functionalized with alkyltriethoxysilane (alkyl = methyl, ethyl, propyl and isobutyl) were prepared. The effects of grafting sequence on the grafting amount were studied. The catalysts were characterized by XRD , FT-IR, elemental analysis , thermogravimetric analysis , nitrogen adsorption-desorption, TEM and XPS , and evaluated using catalytic hydrogenation of 2-ethyl-anthraquinone. The grafting amount increases with increasing the alkyl chain length of alkyltriethoxysilane. The highest grafting amount with the carbon content of 1.56% is obtained using an ante-grafting procedure where the grafting is performed prior to the removal of template, and this catalyst shows the highest activity and selectivity (98.3%). The accordant relationship between the activity of Pd/SBA-15 catalysts and their grafting amount indicates a positive effect of hydrophobicity of SBA-15 created by grafting on the catalytic hydrogenation of 2-ethyl-anthraquinone.
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Evidence-based Complementary and Alternative Medicine
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2018
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IF 2.064
Renjie Xu,Yichu Yuan,Jia Qi,Jia Zhou,Xiaowen Guo,Jian Zhang,Ruanjuan Zhan
Loganin, iridoid glycosides, is the main bioactive ingredients in the plant Strychnos nux-vomica L. and demonstrates various pharmacological effects, though poor oral bioavailability in rats. In this study, the intestinal absorption mechanism of loganin was investigated using the human intestinal Caco-2 cell monolayer model in both the apical-to-basolateral (A-B) and the basolateral-to-apical (B-A) direction; additionally, transport characteristics were systematically investigated at different concentrations, pHs, temperatures, and potential transporters. The absorption permeability (AB) of loganin, which ranged from 12.17 to 14.78 × 10−6cm/s, was high at four tested concentrations (5, 20, 40, and 80μM), while the major permeation mechanism of loganin was found to be passive diffusion with active efflux mediated by multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP). In addition, it was found that loganin was not the substrate of efflux transporter P-glycoprotein (P-gp) since the selective inhibitor (verapamil) of the efflux transporter exhibited little effects on the transport of loganin in the human intestinal Caco-2 cells. Meanwhile, transport from the apical to the basolateral side increased 2.09-fold after addition of a MRP inhibitor and 2.32-fold after addition of a BCRP inhibitor. In summary, our results clearly demonstrate, for the first time, a good permeability of loganin in the human intestinal Caco-2 cell model and elucidate, in detail, the intestinal absorption mechanism and the effects of transporters on iridoid glycosides compounds.
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JOURNAL OF MOLECULAR LIQUIDS
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2018
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IF 4.513
Chuxin Liang,Zheng Liu,Qiuqun Liang,Guo-Cheng Han,Jiaxing Han,Shufen Zhang,Xiao-Zhen Feng
Three new bis-Schiff bases, including bis(2-aminofluorene) glyoxal(L1), bis(2-aminofluorene) p-phthalaldehyde (L2) and bis(2-aminofluorene) 4,4′-biphenyldicarboxaldehyde (L3), were synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR) and mass spectrometry (MS). Weight loss methods indicated that all these inhibitors have good resistance to 1.0 mol·L −1 hydrochloric acid corrosion , and the highest inhibition efficiency was 98.2% at 65 °C for L3. Polarization curves and electrochemical impedance spectroscopy (EIS) indicated that L3 exhibited excellent inhibition effect when concentration was 1.0 mmol·L −1 . Moreover, the L3 was adsorbed spontaneously onto the surface by both physisorption and chemisorption , which followed the Langmuir adsorption isotherm . The relationship between molecular structure and quantum chemical structure parameters of three bis-Schiff base corrosion inhibitors was studied by Quantum chemistry calculation performed by density function theory (DFT) method. Results showed that L3 had excellent inhibition performance, which was consistent with experimental results.
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EUROPEAN JOURNAL OF DRUG METABOLISM AND PHARMACOKINETICS
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2018
·Vol. 44
·期 2
·295-303
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IF 1.362
Xu Renjie,Peng Ying,Wang Mengyue,Li Xiaobo
Background Isoalantolactone and alantolactone are the main sesquiterpene lactones in Radix Inulae (dried root of Inula helenium L. or I. racemosa Hook. F.), which is a frequently utilized herbal medicine. They also occur in several plants and have various pharmacologic effects. However, they have been found to have poor oral bioavailability in rats. Objectives To understand the intestinal absorptive characteristics of isoalantolactone and alantolactone as well specific influx and efflux transporters in their absorption. Methods Bidirectional permeabilities of isoalantolactone and alantolactone were investigated across Caco-2 cell monolayers. Transport assays were performed using different concentrations of two lactones and specific inhibitors of ATP-binding cassette transporters and influx transporters. Results The absorption permeability of isoalantolactone and alantolactone was high at the tested concentrations (5, 20 and 80 μmol/l), and the major permeation mechanism of both lactones was found to be passive diffusion with active efflux mediated by multidrug resistance-associated proteins (MRPs) and breast cancer resistance protein (BCRP). Conclusion Our results demonstrated that the absorption permeability of isoalantolactone and alantolactone was good in the Caco-2 cell model. The isoalantolactone and alantolactone absorption elucidated in this study provides useful information for further pharmacokinetics studies. Since low intestinal absorption can now be ruled out as a cause, further studies are needed to explain the low oral bioavailability of the two sesquiterpene lactones.
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CERAMICS INTERNATIONAL
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2018
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IF 3.057
Shuyang Li,Jian Liu,Xiaoyong Yang,Yi Ding,Lin Zhu,Bo Liu,Ling Zhang,Shilin Luo,Jiehong Lei,Wenkun Zhu,Tao Duan
Zircon ceramics (ZrSiO 4 ) are promising candidates for actinide immobilization. Here, a series of Zr 1- x Nd x SiO 4- x /2 ( x = 0, 0.02, 0.20, and 1.0) ceramics are prepared to study the effects of phase evolution and acidity on the chemical durability of ZrSiO 4 -based nuclear waste forms. The results show that the chemical stability of the single-phase ZrSiO 4 sample is better than that of the biphasic Zr 0.8 Nd 0.2 SiO 3.9 sample due to the existence of a secondary highly soluble phase (Nd 2 Si 2 O 7 ), which increases the contact area with leachate. The normalized release rates of both zirconium (Zr) and neodymium (Nd) in the Zr 1- x Nd x SiO 4- x /2 ceramic waste forms increase with increasing Nd loading and acid concentration. LR Zr in ZrSiO 4 ceramics and LR Nd in Zr 0.98 Nd 0.02 SiO 3.99 ceramics are the lowest, while LR Zr and LR Nd reach the highest values in the Zr 0.8 Nd 0.2 SiO 3.9 and Nd 2 Si 2 O 7 ceramics, respectively. The normalized release rates of Zr are lower than those of Nd due to the difference in the energies of their bonds with oxygen atoms. Moreover, the changes in the surfaces of the leached ceramics are consistent with their leaching results.
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ACS Sustainable Chemistry & Engineering
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2018
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IF 6.14
Yan Xu,Linjie Xie,Di Li,Rong Yang,Deli Jiang,Min Chen
The exploration of earth-abundant and high-efficiency electrocatalysts for water oxidation is of great significance for sustainable energy conversion. Co–Mo-based bimetallic oxides are considered as promising candidates for the oxygen evolution reaction (OER) due to their high intrinsic activity and low cost. In this work, we reported an interfacial engineering design of CoMoO4 nanoplate arrays wrapped with Ni(OH)2 nanosheets supported on Ni foam for high-performance OER. Remarkably, benefiting from the hierarchical heterostructure arrays with strong interfacial interaction, enlarged surface areas, and more active sites, the optimized CoMoO4-Ni(OH)2 electrocatalyst manifests the excellent OER catalytic performance with a low overpotential of 349 mV at the current density of 100 mA cm–2, a long-term stability, and high (nearly 100%) Faradaic efficiency, which is superior to those of most previously reported Co–Mo-based bimetallic oxides electrocatalysts. Therefore, this interfacial engineering demonstrates an effective strategy for designing and fabricating high-performance electrocatalysts for OER reaction.
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JOURNAL OF HAZARDOUS MATERIALS
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2018
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IF 6.434
Lan Cao,Changjun Yang,Bingguang Zhang,Kangle Lv,Mei Li,Kejian Deng
ABSTRACT A new ZnO/CoPz(hmdtn) 4 composite as a highly efficient photocatalyst was successfully prepared by cobalt tetra(2-hydroxymethyl-1,4-dithiin)porphyrazine (CoPz(hmdtn) 4 ) impregnated onto the surface of ZnO nanoparticles, the photocatalytic performance of ZnO/CoPz(hmdtn) 4 under both simulated sunlight and visible light (λ ≥ 400 nm) irradiation was assessed by degradation of Rhodamine B (RhB) and phenol in aerated conditions. The ZnO/CoPz(hmdtn) 4 manifested much higher photocatalytic activity than pure ZnO and pure CoPz(hmdtn) 4 , originating from the synergistic effect between CoPz(hmdtn) 4 and ZnO. Furthermore, the XPS analysis revealed that there may be strong interaction between CoPz(hmdtn) 4 and ZnO. Thereby ZnO/CoPz(hmdtn) 4 with excellent stability can maintain high photocatalytic activity over five runs on the basis of the reusability test. The active species generated in the photocatalytic system were verified by electron spin resonance (ESR) technology. A possible mechanism of the synergistic effect between CoPz(hmdtn) 4 and ZnO was also proposed.
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