CHEMICAL ENGINEERING JOURNAL
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2017
·
IF 6.216
Xiaotong Cao,Jianquan Luo,John M. Woodley,Yinhua Wan
In this study, the biocatalytic membranes were prepared by ‘reverse filtration’ of laccase and subsequently various mussel-inspired coating strategies: single dopamine (DA) deposition, DA/polyethyleneimine (PEI) co-deposition, and DA/Cu 2+ co-deposition, where nanofiltration (NF) membranes were used as the matrix to further exploit the potential of the biocatalytic membranes. Such prepared biocatalytic membranes were enzymatically active on both sides, making it possible to construct a bifacial enzymatic membrane reactor (EMR) for highly efficient micro-pollutants removal (taking bisphenol A (BPA) as an example). Compared with the single polydopamine (PDA) coated membrane, the biocatalytic membranes prepared by DA/PEI and DA/Cu 2+ co-depositions exhibited much better performances in terms of enzyme loading, activity and permeability as well as the stability of immobilized enzyme. The BPA removal efficiency was highest for the EMR with the PDA/Cu 2+ coated membrane attributed to copper-enhanced electron transfer, while it was lowest for the EMR with the PDA/PEI coated membrane due to the high diffusional resistance of the dense PDA/PEI layer. Meanwhile, the mechanism for performance deterioration of biocatalytic membrane during BPA treatment was revealed, and it was found that the trade-off between BPA removal efficiency and long-term stability could be broken by applying the bifacial EMR with PDA/Cu 2+ coated membrane in flow-through mode, since the pressure-induced convective mass transfer improved the substrate accessibility to enzyme together with products removal.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
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2017
·Vol. 164
·期 13
·F1483
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IF 3.259
Yingjie Chen,Shiben Liu,Zhihao Shi,Jianhua Yu,Hongzhou Dong,Yong Qin,Liyan Yu,Lifeng Dong
Ag-MFe2O4 (M = Co, Mn) nanocomposites were synthesized and loaded onto carbon supports. As-prepared Ag-MFe2O4/C demonstrated higher catalytic activity for oxygen reduction reaction (ORR) than Ag+MFe2O4/C. The direct coupling and electron transfer between Ag and MFe2O4 in nanocomposites were proposed to enhance their catalytic activities. The Koutecky-Levich plots confirmed a direct four-electron reaction pathway for the ORR on Ag-MFe2O4/C. Furthermore, Ag-MFe2O4/C showed superior catalytic activities and excellent stability for oxygen evolution reaction (OER). Thus, Ag-MFe2O4/C nanoparticle are potential non-Pt candidates with bi-functional catalytic activity for ORR and OER.
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RSC Advances
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2017
·Vol. 7
·期 72
·45280-45286
·
IF 3.108
Bo Tang,Guojian Ji,Zhengwei Wang,Haiqun Chen,Xufei Li,Haogang Yu,Sen Li,Hong Liu
Graphene assisted dye-sensitized solar cells (DSSCs) have drawn increasing attention because of their high performances. However, two bottlenecks (the high defect density and the discontinuous structure) of the widely adopted reduced graphene oxide (RGO) nanosheets bring about that the practical photovoltaic properties are far inferior to the theoretical prediction values. Therefore, three-dimensional graphene networks (3DGNs) of high quality have been employed to modify DSSCs to avoid the above mentioned problems. However, a close contact between the graphene basal plane and TiO2 particles in the resulting photoanode is difficult to achieve due to the absence of surface functional groups of the 3DNG. In this study, the RGO nanosheets and 3DGNs co-modified DSSCs are prepared, and the advantages from these two modifiers can give full play to their synergy. The added RGO nanosheets enhance the electron transport ability at the interfaces between graphene, TiO2 and conductive substrate. After optimizing the reduction degree and mass fraction of the RGO nanosheets, the power conversion efficiency of the resulting DSSC reaches 7.68%, which is much higher than those cases of using the 3DGNs (or RGO nanosheets) as modifier alone.
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JOURNAL OF NANOBIOTECHNOLOGY
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2015
·Vol. 13
·期 1
·1-11
·
IF 4.115
Wang Bing,Yu Xiu-Chun,Xu Song-Feng,Xu Ming
Background The combination of chemotherapeutic drugs with different pharmacological action has emerged as a promising therapeutic strategy in the treatment of cancers. Present study examines the antitumor potential of paclitaxel (PTX) and etoposide (ETP)-loaded PLGA nanoparticles for the treatment of osteosarcoma.Results The resulting drug-loaded PLGA NP exhibited a nanosize dimension with uniform spherical morphology. The NP exhibited a sustained release profile for both PTX and ETP throughout the study period without any sign of initial burst release. The combinational drug-loaded PLGA NP enhanced the cytotoxic effect in MG63 and Saos-2 osteosarcoma cell lines, in comparison to either native drug alone or in cocktail combinations. Additionally, NPs showed an appreciable uptake in MG63 cells in a time-based manner. Co-delivery of anticancer drugs resulted in enhanced cell cycle arrest and cell apoptosis. The results clearly showed that combinational drugs remarkably improved the therapeutic index of chemotherapeutic drugs. The greater inhibitory effect of nanoparticle combination would be of great advantage during systemic cancer therapy.Conclusion Taken together, our study demonstrated that PTX-ETP/PLGA NP based combination therapy holds significant potential towards the treatment of osteosarcoma.
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DESIGNED MONOMERS AND POLYMERS
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2015
·
IF 2.78
Guang-Zhen Mo,Yan-Cheng Wu,Zhi-Feng Hao,Qiao-Fang Luo,Xin-Yu Liang,Li-Tao Guan,Zhao-Yang Wang
Using aminomethyl benzimidazole (AMB) as a model of benzimidazole-type drugs, a potential biodegradable drug-loaded polymer poly(lactic acid-co-aminomethyl benzimidazole) (PLAAMB) is synthesized as designed via direct melt polycondensation starting from d,l-lactic acid (LA). When the molar feed ratio LA/AMB is 40/1, the optimal synthetic conditions, including catalyst type and dosage, polycondensation temperature, and copolymerization time are discussed. After the prepolymerization at 140 °C for 8 h, using 0.4 wt% stannous oxide (SnO) as the catalyst, the melt copolymerization at 160 °C for 6 h gives the copolymer with the biggest weight-average molecular weight (Mw) 5300 Da. The structure and properties of the copolymer are systematically characterized with Fourier transform infrared, 1H NMR, gel permeation chromatography, differential scanning calorimetry, and X-ray diffraction. And the investigations on the influences of different molar feed ratios on the properties of PLAAMB show that, the copolymer PLAAMB with the biggest Mw of 9400 Da can be obtained. After the drug model AMB as a monomer is introduced into polylactic acid during the condensation, the Tg of the obtained PLAAMB is lower than the Tg of homopolymer poly(d,l-lactic acid) (PDLLA). The Mw and crystallinity of PLAAMBs can meet the requirement of drug-loaded polymers in the drug delivery.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2014
·
IF 6.007
Moa Z. Granlund,Kjell Jansson,Marita Nilsson,Jazaer Dawody,Lars J. Pettersson
The objective of this paper was to study the influence three promoters (Co, La, Mn) had on the catalytic activity of Rh-based catalysts for autothermal reforming of diesel. The catalysts were supported on CeO 2 -ZrO 2 and the loading was 1 wt.% Rh and 6 wt.% promoter. The catalytic activity was evaluated in a monolith bench scale reactor with Swedish Environmental diesel, MK1. The process parameters employed at the ATR experiments were; O 2 /C ∼ 0.45, H 2 O/C ∼ 2.5 and GHSV ∼ 50,000 h −1 , meanwhile the reactor temperature was ramped from 700 °C to 950 °C. The catalysts were compared based on their fuel conversion, H 2 yield and the selectivity of different short-chain hydrocarbons. The results showed that all three catalysts had both high fuel conversion and H 2 yield in the optimal ATR operation temperatures. The H 2 yield and fuel conversion were increasing in the order Rh/Mn, Rh/La, Rh/Co. To get further insight in the difference between the materials the fresh and aged catalytic materials were characterized. The characterization methods used were H 2 -temperature programmed reduction (H 2 -TPR), powder X-ray diffraction (XRD), and BET surface measurements. The BET surface measurements showed that promotion with La gave improved thermal stability of the material. The XRD showed a high dispersion of all metals except Co, which was present as crystals in the size range of the particles of the support.
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CHINESE JOURNAL OF POLYMER SCIENCE
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2015
·Vol. 34
·期 1
·104-110
·
IF 1.835
Liu Bo,Liu Dong-tao,Li Shi-hui,Sun Guang-ping,Cui Dong-mei
β -Iminophosphonamide ligated lanthanum bis(benzyl) complex (NPN Dipp )La(CH 2 Ph-4-Me) 2 (THF) (NPN Dipp = Ph 2 P(NC 6 H 3
i Pr 2 -2,6) 2 ), upon activation of AlEt 3 and [Ph 3 C][B(C 6 F 5 ) 4 ], exhibited high catalytic activity and high trans -1,4 stereoselectivity for the polymerization of bio-sourced β -myrcene (MY). Based on which, a series of novel trans -1,4 regulated elastomers could be generated by random/block copolymerization of MY and isoprene (IP).
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Materials
·
2015
·Vol. 8
·期 3
·1009-1026
·
IF 2.651
Juan Wang,Dongsong Li,Tianyi Li,Jianxun Ding,Jianguo Liu,Baosheng Li,Xuesi Chen
Surface coating is the simplest surface modification. However, bioactive molecules can not spread well on the commonly used polylactone-type skeletons; thus, the surface coatings of biomolecules are typically unstable due to the weak interaction between the polymer and the bioactive molecules. In this study, a special type of poly(lactide-co-glycolide) (PLGA)-based scaffold with a loosened skeleton was fabricated by phase separation, which allowed gelatin molecules to more readily diffuse throughout the structure. In this application, gelatin modified both the internal substrate and external surface. After cross-linking with glutaraldehyde, the surface layer gelatin was tightly bound to the diffused gelatin, thereby preventing the surface layer gelatin coating from falling off within 14 days. After gelatin modification, PLGA scaffold demonstrated enhanced hydrophilicity and improved mechanical properties (i.e., increased compression strength and elastic modulus) in dry and wet states. Furthermore, a sustained release profile of recombinant human bone morphogenetic protein-2 (rhBMP-2) was achieved in the coated scaffold. The coated scaffold also supported thein vitroattachment, proliferation, and osteogenesis of rabbit bone mesenchymal stem cells (BMSCs), indicating the bioactivity of rhBMP-2. These results collectively demonstrate that the cross-linked-gelatin-coated porous PLGA scaffold incorporating bioactive molecules is a promising candidate for bone tissue regeneration.Keywords:biomaterials;bone tissue engineering;gelatin;surface coating;recombinant human bone morphogenic protein-2
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Food and Bioprocess Technology
·
2014
·Vol. 7
·期 11
·3121-3135
·
IF 3.126
Tian Ye,Fu Nan,Wu Winston Duo,Zhu Danhua,Huang Jinjian,Yun Shuo,Chen Xiao Dong
Dairy industries often spray lecithin, a food-grade surfactant, to spray-dried whole milk powders while fluidisation to produce instant powders. Though adding surfactant to milk feed was often reported to improve the wettability of dried powders, this approach was not favourably used. The present study investigated the effects of surfactant addition into high solids milk feed before drying on the wettability of whole milk particles. Adding either 0.1 wt.% Tween 80 or 0.1 wt.% lecithin to un-concentrated whole milk led to a significant wettability improvement of spray-dried powders. At higher feed solids levels of 23 and 33 wt.%, the wetting process of pure milk powders was comparatively rapid, but the surfactant-added powders showed similar wettability to the pure milk powders. The development of powder wettability as drying progressed was investigated using single droplet-drying technique for 32 and 43 wt.% whole milk in the presence and absence with surfactants. The technique captured an advanced shell formation during drying of higher solids milk. The wettability of surface shells formed by surfactant-added milk was similar to those formed by pure milk throughout drying, from initial shell formation to final drying stage. By contrast, coating surfactants on the outer layer of particles being dried could substantially improve wettability. The rapid shell formation and the slow material diffusion owing to the high medium viscosity were considered the main factors limiting the migration of surfactant molecules towards droplet surface during drying.
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CARBOHYDRATE POLYMERS
·
2013
·
IF 3.479
Yiming Zhou,Shiyu Fu,Liangliang Zhang,Huaiyu Zhan
Superabsorbents based on carboxylated cellulose nanofibrils (CCNFs) and carboxymethyl cellulose-g-poly(acrylic acid-co-acrylamide) were synthesized. A series of experiments were performed to evaluate the influence of factors such as CCNFs amount, solution pH, temperature, salt solution type and concentration on the swelling behaviors of the hydrogels. The water uptake of the hydrogels strongly depended on the CCNF content, the swelling capacity in distilled water increased dramatically from 245.8 to 458.7 g/g with the addition of CCNFs up to 2.5 wt%. Furthermore, the incorporation of CCNFs improved salt resistance properties of the hydrogels with slower deswelling rate and higher water retention capacity at deswelling equilibrium. Besides, the CCNF nanocomposite hydrogels presented better responsive behavior in relation to pH presence and showed an increase in water retention capacity at various temperatures. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were employed to examine the structure and morphologies of the prepared superabsorbent hydrogels.
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Biomicrofluidics
·
2013
·Vol. 7
·期 4
·
IF 3.385
Liu Zhou,Shum Ho Cheung
In this work, we demonstrate a robust and reliable approach to fabricate multi-compartment particles for cell co-culture studies. By taking advantage of the laminar flow within our microfluidic nozzle, multiple parallel streams of liquids flow towards the nozzle without significant mixing. Afterwards, the multiple parallel streams merge into a single stream, which is sprayed into air, forming monodisperse droplets under an electric field with a high field strength. The resultant multi-compartment droplets are subsequently cross-linked in a calcium chloride solution to form calcium alginate micro-particles with multiple compartments. Each compartment of the particles can be used for encapsulating different types of cells or biological cell factors. These hydrogel particles with cross-linked alginate chains show similarity in the physical and mechanical environment as the extracellular matrix of biological cells. Thus, the multi-compartment particles provide a promising platform for cell studies and co-culture of different cells. In our study, cells are encapsulated in the multi-compartment particles and the viability of cells is quantified using a fluorescence microscope after the cells are stained for a live/dead assay. The high cell viability after encapsulation indicates the cytocompatibility and feasibility of our technique. Our multi-compartment particles have great potential as a platform for studying cell-cell interactions as well as interactions of cells with extracellular factors.
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JOURNAL OF SOLID STATE CHEMISTRY
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2015
·
IF 2.133
Na Zhang,Lei Shi,Tingting Yu,Tianduo Li,Wei Hua,Cong Lin
Pure STW-type germanosilicate (denoted as GeSi-STW), Cu- and Co-containing STW-zeotype (denoted as Cu-STW and Co-STW) materials were synthesized by the hydrothermal method in the presence of an organic structure-directing agent (OSDA), N , N -diethylethylenediamine (DEEDA). The effects of the reaction mixture ratio and the incorporation of transition metals M ( M =Cu and Co) on the synthesis of the pure product was investigated. The synthesized samples were characterized by powder and single-crystal X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma analysis (ICP), thermogravimetric and differential scanning calorimetry (TG–DSC) analysis and UV–vis diffuse reflectance spectra (DRS). The results reveal that the crystallization time, the concentration of H 2 O in the reaction mixture and the addition of HF all have an important impact on the synthesis of pure STW-type zeolite . GeSi-STW is stable up to 800 °C, and has much higher thermal stability than SU-32 (stable to 400 °C). Co and Cu have been introduced for the first time into STW-zeotype materials.
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