JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
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2018
·Vol. 33
·期 1
·226-232
·
IF 0.524
Chen Gang,Lei Jiaheng,Du Yong,Chen Xuebing
The dispersion ability of polycarboxylate superplasticizer (PCE) in fresh concrete was much impeded by clay impurities. To improve the dispersion of PCE in the clay-contained concrete, a novel PCE with carboxyl as a specific branched chain terminal group was synthesized, using modified polyether as the raw material which was prepared through esterification between hexahydrophthalic anhydride (HHPA) and isobutenyl polyoxyethylene ether (IPEG) with hydroxy as the terminal group. The esterification product and PCE molecular structure were characterized by infrared spectroscopy and 1HNMR resonance. The results confirmed that the product molecular structure was a comb-type copolymer with long-chain terminal carboxyl group and PEO attached directly to the backbone chain. The as-synthesized PCEs had favorable dispersibility in cement than conventional PCE in the presence of montmorillonite (Mmt) clay. This can be attributed to the introduction of electronegative carboxyl to PCE long-chain terminal group, which reduces the adsorption of PCE on Mmt, and thus improves the tolerance of PCE to the Mmt.
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COLLOID AND POLYMER SCIENCE
·
2018
·Vol. 296
·期 3
·471-481
·
IF 1.967
Han Lidong,Yang Rong,Yuan Shengxiao,Ding Shuang,Wu Ziheng,Wu Zhenghong,Qi Xiaole
Multiple emulsions are potential transdermal drug carriers for their remarkable ability to enhance skin permeability, but their intrinsic thermodynamically instability always limits further application. Here, we developed freeze-thawing water-in-oil-in-water multiple emulsion transdermal drug delivery system, which could accomplish solid-liquid transition in freeze-thawing cycles and keep stable under hypothermic storage (4 °C). In this study, freeze-thawing multiple emulsions were prepared by a two-step emulsification method with isopropyl palmitate as the oil phase, which could freeze at 4 °C to gain solid multiple emulsions and regain intact liquid emulsions at a shell temperature (32 °C) upon application on the skin. In vitro skin permeation studies on excised mice skin showed that the cumulative permeation percentages of diclofenac sodium from freeze-thawing multiple emulsions, multiple emulsions, and cream (Dakangfen®) were 41.22 ± 4.27, 36.63 ± 4.71, and 23.96 ± 3.49% separately. Moreover, pharmacokinetic experiments in rabbits indicated that the AUC 0 − t (area under the curve) of freeze-thawing multiple emulsions (30.872 ± 3.989 μg/mL h) and multiple emulsions (27.337 ± 2.804 μg/mL h) were significantly higher than those of the controlled cream (14.981 ± 1.331 μg/mL h) ( p < 0.05). These results suggested that freeze-thawing multiple emulsions could be a promising substitute of traditional multiple emulsions for transdermal drug delivery.
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Scientific Reports
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2018
·Vol. 8
·期 1
·1-18
·
IF 4.122
Zhou Bohang,Zhang Bingyu,Li Xingqiang,Liu Xiuxiu,Li Hui,Li Ding,Cui Zhiming,Geng Huiling,Zhou Le
A series of 2-aryl-9-methyl- β -carbolinium bromides (B) were synthesized and explored for anti-acetylcholinesterase (AChE) activities in vitro , action mechanism and structure-activity relationship. All the compounds B along with their respective 3,4-dihydro intermediates (A) presented anti-AChE activity at 10 μM. Thirteen compounds B showed the excellent activity with IC 50 values of 0.11 – 0.76 μM and high selectivity toward AChE relative to butyrylcholinesterase (BChE), superior to galantamine (IC 50 = 0.79 μM), a selective AChE inhibitor drug. Kinetic analysis showed that the action mechanisms of both compounds B and A are a competitive inhibition model. Structure-activity relationship analyses showed that the C = N + moiety is a determinant for the activity. Substituents at 6, 7 or 4′ site, the indole-N-alkyl and the aromatization of the C-ring can significantly improve the activity. Molecular docking studies showed that the compounds could combine with the active site of AChE by the π-π or cation-π action between the carboline ring and the phenyl rings of the residues, and the β-carboline moiety is embedded in a cavity surrounded by four aromatic residues of Trp86, Tyr337, Trp439 and Tyr449. The present results strongly suggest that the para-position of the D-ring should be a preferred modification site for further structural optimization design. Thus, 2-aryl-9-methyl- β -carboliniums emerged as novel and promising tool compounds for the development of new AChE inhibitor agents.
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Scientific Reports
·
2018
·Vol. 8
·期 1
·1-11
·
IF 4.122
Tang Shanshan,Tsona Narcisse T.,Du Lin
In order to investigate ring-size effects on the stability and spectral shifts of hydrogen bonded cyclic ethers complexes, the strength of hydrogen bonds in gas phase complexes formed between 2,2,2-trifluoroethanol (TFE) and selected cyclic ethers were examined using FTIR spectroscopy. TFE was chosen as hydrogen bond donor in these complexes, while trimethylene oxide (TMO), tetrahydrofuran (THF) and tetrahydropyran (THP) were selected as hydrogen bond acceptors. Comparable OH-stretching red shifts were observed in the three kinds of complexes. The difference of red shifts is so small (<7 cm −1 ) for TFE−TMO/THF/THP complexes that one can conclude that their stabilities and the strength of the hydrogen bonds are nearly similar and do not show any marked dependence with the ring size of the hydrogen bond acceptor. The equilibrium constants for the complexation were determined, and atoms-in-molecules (AIM) and natural bond orbital (NBO) analyses were performed to further investigate the intermolecular interactions. Regardless of the ring size, hydrogen bonds in the complexes showed similar strength, in agreement with the observed OH-stretching red shifts.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 4
·2889-2911
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IF 1.674
Qi Caixia,Liu Huijun,Deng Shanxia,Yang AoHui,Li Zhendong
The inclusion complex (sulfated-β-CD@NAA) of sulfated β-cyclodextrin and α-naphthylacetic acid was synthesized for adsorption of low concentrations of thorium from aqueous solutions. The structure and property of sulfated-β-CD@NAA were characterized by Fourier transform infrared spectroscopy, thermogravimetric, X-ray diffraction, proton nuclear magnetic resonance, specific surface area measurement and scanning electron microscopy. The characterization analysis confirmed the formation of new solid phase. The results indicated that α-naphthylacetic acid embedded into the cavity of sulfated β-cyclodextrin partly from the secondary face and the thermal stability of inclusion complex was significantly increased. The experiments were designed by Box–Behnken design combined with response surface methodology. The adsorption parameters of pH value, contact time, initial concentration were used as the independent variables and their effects were investigated on the Th(IV) adsorption capacity. Second-order polynomial regression models were derived and analysis of variance was utilized to judge the adequacy of the chosen models. The maximum Th(IV) adsorption capacity (12.75 mg g −1 ) was achieved under the following conditions: pH value 2.5, contact time 35 min, initial concentration 30 mg L −1 . Prediction of models was in good agreement with experimental results. The experimental adsorption kinetic data followed a pseudo-second-order equation with the correlation of 0.9996, indicating the chemical adsorption. The obtained equilibrium isotherm data were fitted well with Langmuir model in the concentration range considered. The thermodynamic parameters ( ∆H 0 < 0, ∆S 0 < 0, ∆G 0 < 0) indicated that the adsorption process was exothermic and spontaneous. Regeneration of Th(IV)-loaded sulfated-β-CD@NAA with 0.1 M HNO 3 solution, and the regenerated sulfated-β-CD@NAA can be reused for adsorption of Th(IV).
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TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 24
·期 4
·301-307
·
IF 0
Qi Wei,Fang Jie,Yang Zhenzhen,Li Bingqi,Su Rongxin,He Zhimin
A low-cost and easily prepared manganese carbonate (MnCO 3 ) has been synthesized for catalytic conversion of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF). The properties and morphology of the manganese carbonate were measured by SEM, XRD, TGA, BET and XPS. In this method, no harsh reaction conditions were required, and it was a simple and green process for the oxidation of 5-HMF into DFF. To achieve an optimum DFF yield, different reaction conditions, including reaction temperature, reaction time, catalyst amount, and solvents were investigated. Results from the experiments indicated that the highest DFF yield of 86.9% was obtained at 120 °C under atmospheric oxygen pressure after 6 h. Finally, MnCO 3 could be used at least five times with considerable stability.
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JOURNAL OF NANOPARTICLE RESEARCH
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2018
·Vol. 20
·期 10
·1-11
·
IF 2.127
Feng Runliang,Deng Peizong,Zhou Feilong,Feng Sijia,Song Zhimei
To overcome honokiol’s poor water solubility and investigate its antifungal activity and pharmacokinetic property, Pluronic® F-127 (F127)-cyclodextrin conjugate was synthesized and employed to prepare honokiol-loaded micelles through emulsion-solvent evaporation method. The drug-loaded micelles were obtained with 92.30 ± 3.28% of encapsulation efficiency being higher than that obtained from F127 due to additional cyclodextrin inclusion. Fourier transformation infrared spectrometry and diffraction scanning calorimetry analysis tests demonstrated that honokiol was successfully encapsulated into the conjugate micelles in the amorphous or solid solution state because of their interactions. Meanwhile, in vitro antifungal activity experiment indicated that the MIC 90 of drug-loaded micelles was 64 μg/mL, showing the same antifungal activity as pure honokiol although it obviously retarded honokiol’s release. In vivo pharmacokinetic results confirmed that in vivo area under curve and apparent distribution volume of honokiol in drug-loaded micelles were 2- and 1.69-folds higher than that for pure honokiol, with its obvious prolonged mean retention time and half-life period, respectively. The clearance rate of honokiol was also shortened about 2-fold in comparison with pure honokiol when encapsulated into the micelles. These results suggest that the developed F127-cyclodextrin micellar formulation is a promising drug delivery system for antifungal drugs.
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JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
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2018
·
IF 2.869
Min Tao,Li Zhang,Yinlong Guo
A novel dual-channel enzymatic inhibition measurement (DEIM) method was developed to improve the repeatability with light/heavy isotope substrates, producing reliable relative standard deviations (< 3%) by employing acetylcholinesterase (AChE) as the model enzyme. The matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was adapted for enzyme-inhibited method due to its good salt-tolerance and high throughput; meanwhile, dual-channel enzymatic reactions were performed to improve the repeatability of each well. The acetylcholinesterase inhibition measurement was conducted by mixing the quenched enzyme reaction solution of blank group (with heavy isotope as substrate) and experimental group (with light isotope as substrate), of which the inhibition rate might be affected by isotope effects. Hence, inverse study and Km measurement were implemented to validate the method. The inverse study shows similar inhibition rate (68.9 and 70.3%) and the Km of isotope substrates are analogous (0.139 and 0.135 mM), which demonstrated that the novel method is feasible to AChE inhibition measurement. Finally, the method was applied to herb extracts, half of which exhibit inhibition to AChE. The precise dual-channel enzymatic inhibition measurement (DEIM) method could be regarded as a promising approach to potential enzyme inhibitor screening.
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FIBERS AND POLYMERS
·
2018
·Vol. 19
·期 8
·1715-1725
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IF 1.353
Deb Hridam,Xiao Shili,Morshed Mohammad Neaz,Al Azad Shamim
We report a facile approach to fabrication and characterization of cationic titanium dioxide (TiO 2 + ) on poly (vinyl alcohol)/poly (acrylic acid) (PVA/PAA) composite electro-spun nanofibrous mat. The aim of this study is to develop a “functional electrospun nanofibrous mat” as a sustainable approach to superior photocatalytic degradation of organic colorants. For that, the PVA/PAA nanofibrous mat was prepared by electrospinning of PVA and PAA solution according to an aspect ratio of 1:1 and later water stability was induced by the thermal cross linking at an elevated temperature of 145 °C for 30 minute. By means of electrostatic layer-by-layer (LbL) assembly, cationic titanium dioxide (TiO 2 + , ~19 nm) was immobilized on the surface of the water stable nanofibrous mat. As functionalized composited nanofibrous mat was characterized by using scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis and thermogravimetric analysis (TGA). Superior competency of the functionalized nanofibrous mat towards photocatalytic degradation of organic dye (methyl blue) in aqueous solution was observed by using UV-visible spectrophotometer with quantitative measuring method. The result indicates a complete degradation of methyl blue within 40 mins and superior reusability upto 5 cycles application. The study signifies the prospect of using electrospun nanofibers to manipulate the catalytic activity, which could be a foundation for further rational design of various composite nanofibrous materials.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 22
·22244-22258
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IF 2.8
Yan Xuechao,Zhang Xiaoping,Li Qian
In this paper, an effective chitosan/beta-cyclodextrin/nanometer zinc oxide (CS/β-CD/Nano-ZnO) composite porous membrane was synthesized by sol-gel and polymer-assisted inverting method. Preparation conditions of CS/β-CD/Nano-ZnO were investigated by single-factor and Box-Behnken response surface methodology optimizing triethoxyvinylsilane (JH-V151), beta-cyclodextrin (β-CD), and nanometer zinc oxide (Nano-ZnO), and applied to study the adsorption characteristics of Cong red (CR) from aqueous solution using batch experiments. The optimum preparation conditions were determined that the volume fraction of JH-V151 alcohol solution was 11%, the ratio of β-CD to CS was 5.35, and the ratio of Nano-ZnO’s mass to solution’s volume was 0.36%. Different characterization methods including field-emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and Universal Materials Tester were used to prove the appearance, crystallinity, functional groups, swelling degree, transmittance, and tensile property of CS/β-CD/Nano-ZnO. The optimized batch experimental parameters were 50 mg L −1 , 4 h, 7.0, 0.5 g L −1 , and 55.0 °C as initial concentration, contact time, pH, adsorbent dose, and temperature, respectively. The maximum adsorption capacity on CR reached 96.33 mg g −1 , which is 4.34 times with respect to CS. The batch experimental data were best described by a pseudo-second-order kinetics model and Langmuir isotherm model ( R 2 = 0.9965, theoretical saturated adsorption capacity 147.28 mg g −1 ). The values ∆G were − 2.09, − 4.73, and − 7.37 kJ mol −1 at 298, 308, and 318 K temperatures, respectively. The ∆H value was 76.68 kJ mol −1 , indicating the endothermic and spontaneous adsorption in nature. The ∆S value was 0.26 kJ mol −1 K −1 , a signal of entropy increase during adsorption. The adsorption capacity decreased only by 5.8% after six recycling runs, which indicated the reusability of CS/β-CD/Nano-ZnO. Therefore, the CS/β-CD/Nano-ZnO composite porous membrane is a promising membrane material for the efficient removal of CR from any water at large and economic scales at moderate concentration.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2018
·Vol. 36
·期 11
·1207-1216
·
IF 2.016
Zhang Wei,Jiang Bin-Bo,Ye Jian,Liao Zu-Wei,Huang Zheng-Liang,Wang Jing-Dai,Yang Yong-Rong
In this study, a series of aryloxy-aluminoxanes originated directly from the hydrolysis of reaction products of AlMe 3 and phenols were synthesized, which could serve as effective polymer-retarding activators for the iron-catalyzed ethylene oligomerization. The molar ratios of [PhOH]/[AlMe 3 ] and [H 2 O]/[Al] during the preparation were explored and their impacts on the oligomerization activity and product distribution were discussed. To obtain the effective activators with good polymer-retarding effect and relatively high activity, the optimized conditions were proposed to be [PhOH]/[AlMe 3 ] = 0.5 and [H 2 O]/[Al] = 0.7. Various aluminoxanes with different [―OH] sources confirmed the importance of using phenols in preparing the effective polymer-retarding activators. By utilizing these aryloxy-aluminoxanes, the mass fraction of polymers in the total products could be reduced to lower than 1.0 wt%, which is much lower than that of the MAO-activated systems (> 30 wt%). This is a potential benefit for the industrial application of the iron-catalyzed oligomerization process.
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Science China-Chemistry
·
2018
·Vol. 61
·期 11
·1470-1474
·
IF 4.448
Wang Lu-Liang,Yang Cheng-Xiong,Yan Xiu-Ping
Covalent organic frameworks (COFs) have been widely applied in gas capture and separation, but the fluorescent property of COFs with large π-conjugated system tends to be underexplored. Here we report the fluorescent properties of several COFs including TaTa, DhaTab, TRITER-1 and TzDa and the effect of metal ions of Na + , Mg 2+ , K + , Ca 2+ , Cu 2+ , Zn 2+ , Pb 2+ , Ag + , Cd 2+ and Fe 3+ on the fluorescence of these COFs. The results show that only Fe 3+ significantly quenched the fluorescence of the studied COFs. The possibility of the four COFs for selective sensing of Fe 3+ was demonstrated. The possible mechanism of the effect of Fe 3+ on the fluorescence of the COFs was based on the absorption competition quenching.
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