Nanoscale Research Letters
·
2016
·Vol. 11
·期 1
·1-9
·
IF 2.584
Zhang Xianghua,Xu Hongxiang,Wang Jiangtao,Ye Xia,Lei Weining,Xue Maoquan,Tang Hua,Li Changsheng
In this paper, ultrathin WS 2 nanosheets with thickness of about 5 nm were successfully prepared by a facile solid phase reaction method. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). On the basis of experimental results obtained under different reaction durations, a possible formation mechanism of WS 2 nanosheets is proposed. The tribological performance of ultrathin WS 2 nanosheets as additives in the 500SN base oil was tested by an UMT-2 ball-on-disc tribotester, and the worn surface of the steel disc was investigated by a non-contact optical profile testing instrument and SEM. The results showed that the friction coefficient and anti-wear property of base oil can be improved strikingly by adding ultrathin WS 2 nanosheets. Especially, when the concentration of WS 2 nanosheets was 1.0 wt.%, the corresponding lubricating oil exhibited the best tribological properties. Moreover, according to the investigation of the wear scar, an anti-friction and anti-wear mechanism is proposed. It is believed that the reduction of friction and wear must come from the addition of ultrathin WS 2 nanosheets which can penetrate and enter the friction interface and form a continuous tribofilm on the rubbing face.
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ORIGINS OF LIFE AND EVOLUTION OF BIOSPHERES
·
2016
·Vol. 47
·期 4
·413-425
·
IF 1.141
Zhang Xianlong,Tian Ge,Gao Jing,Han Mei,Su Rui,Wang Yanxiang,Feng Shouhua
Submarine hydrothermal vents are generally considered as the likely habitats for the origin and evolution of early life on Earth. In recent years, a novel hydrothermal system in Archean subseafloor has been proposed. In this model, highly alkaline and high temperature hydrothermal fluids were generated in basalt-hosted hydrothermal vents, where H 2 and CO 2 could be abundantly provided. These extreme conditions could have played an irreplaceable role in the early evolution of life. Nevertheless, sufficient information has not yet been obtained for the abiotic synthesis of amino acids, which are indispensable components of life, at high temperature and alkaline condition. This study aims to propose a new method for the synthesis of glycine in simulated Archean submarine alkaline vent systems. We investigated the formation of glycine from ethanolamine under conditions of high temperature (80–160 °C) and highly alkaline solutions (pH = 9.70). Experiments were performed in an anaerobic environment under mild pressure (0.1–8.0 MPa) at the same time. The results suggested that the formation of glycine from ethanolamine occurred rapidly and efficiently in the presence of metal powders, and was favored by high temperatures and high pressures. The experiment provides a new pathway for prebiotic glycine formation and points out the phenomenal influence of high-temperature alkaline hydrothermal vents in origin of life in the early ocean.
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CHROMATOGRAPHIA
·
2016
·Vol. 79
·期 21
·1543-1552
·
IF 1.332
Liu Hongru,Pang Zhengji,Fan Guoliang
A novel algorithm, translation modification iteration (TMI), is proposed for resolving overlapping chromatographic peaks. By this method, a series of similar peaks are obtained from the initial construction of single component peaks and approach the profiles of real single component peaks by iteration. Both simulated and experimental data are investigated with TMI, consequently overlapping peaks can be resolved into reasonable single component peaks easily and efficiently. Quantitative analysis is also successfully achieved in both simulated and experimental data, and the quantitative results obtained from TMI are superior to those obtained from perpendicular drop (PD) and tangent skim (TS) methods. Without too much time devoted to the procedure, TMI is a simple and practicable method for resolution and quantification of overlapping chromatographic peaks.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·2031-2037
·
IF 4.831
Xu Guiyun,Liang Shaoping,Fan Jinshi,Sheng Ge,Luo Xiliang
Negatively charged carboxylated nanocrystalline cellulose (CNCC) and positively charged poly(diallyldimethyl ammonium chloride) (PDDA) were alternatingly assembled on the surface of a glassy carbon electrode to form a relatively uniform polyelectrolyte multilayer nanocomposite (CNCC/PDDA) n . It was then incorporated into a matrix of conducting poly(3,4-ethylenedioxythiophene) (PEDOT) electrodeposited on the surface of the electrode. The nanocomposites were prepared in various ratios of PEDOT and (CNCC/PDDA), and then characterized by transmission electron microscopy, scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. The PEDOT/(CNCC/PDDA) 4 nanocomposite showed the lowest electrochemical impedance and best electrocatalytic activity towards the oxidation of nitrite. Based on these findings, an amperometric sensor was developed which, if operated at 0.80 V (vs. SCE), can detect nitrite in the 0.2 μM to 1.73 mM concentration range with a 57 nM detection limit.
Carboxylated nanocrystalline cellulose (CNCC) and poly(diallyldimethyl ammonium chloride) (PDDA) were assembled to nanocomposite (CNCC/PDDA) n . Poly(3,4-ethylenedioxythiophene (PEDOT) was electrodeposited on the surface of (CNCC/PDDA) n and a sensitive amperometric sensor for detection of nitrite was developed based on PEDOT/(CNCC/PDDA) n .
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JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
·
2016
·Vol. 43
·期 4
·557-566
·
IF 2.745
Cao Weijia,Ma Weichao,Zhang Bowen,Wang Xin,Chen Kequan,Li Yan,Ouyang Pingkai
The development of efficient microbial processes for pinocembrin production has attracted considerable attention. However, pinocembrin biosynthetic efficiency is greatly limited by the low availability of the malonyl-CoA cofactor in Escherichia coli. Fatty acid biosynthesis is the only metabolic process in E. coli that consumes malonyl-CoA; therefore, we overexpressed the fatty acid biosynthetic pathway enzymes β-ketoacyl-ACP synthase III (FabH) and β-ketoacyl-ACP synthase II (FabF) alone and in combination, and investigated the effect on malonyl-CoA. Interestingly, overexpressing FabH, FabF or both enzymes in E. coli BL21 (DE3) decreased fatty acid synthesis and increased cellular malonyl-CoA levels 1.4-, 1.6-, and 1.2-fold, respectively. Furthermore, pinocembrin production was increased 10.6-, 31.8-, and 5.87-fold in recombinant strains overexpressing FabH, FabF and both enzymes, respectively. Overexpression of FabF, therefore, triggered the highest pinocembrin production and malonyl-CoA levels. The addition of cerulenin further increased pinocembrin production in the FabF-overexpressing strain, from 25.8 to 29.9 mg/L. These results demonstrated that overexpressing fatty acid synthases can increase malonyl-CoA availability and improve pinocembrin production in a recombinant E. coli host. This strategy may hold promise for the production of other important natural products in which cellular malonyl-CoA is rate limiting.
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JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 51
·期 13
·6379-6388
·
IF 2.302
Gao Nengwen,Fan Yiqun,Quan Xuejun,Cai Yongwei,Zhou Dewen
Growing environmental concerns have fueled the need for efficient separation of oil–water mixtures. Membranes that separate oil–water mixture based on contrasting wetting properties have recently received significant attention. Here, hydrophobic and oleophilic ceramic membranes have been successfully prepared for the application of water-in-oil emulsion separation. The membranes were fabricated by modification the ZrO 2 membrane with hexadecyltrimethoxysilane (HDTMS). SEM, EDS, and pore size measurements depict that HDTMS has been grafted onto the ZrO 2 membrane surface without changing the membrane morphology and pore structure. Contact angle measurements confirm that HDTMS modification improves the membrane hydrophobicity and oleophilicity. The modified membrane was thermally stable to 220 °C, and had good chemical stability in a series of organic solvents, even under high-speed scouring. The antifouling performance of the modified membrane was assessed via the filtration of water-in-oil emulsions. The modified membranes showed higher oil flux and higher water rejection compared with the unmodified membranes. The modified membrane can separate all the water droplets from the water-in-oil emulsions. The hydrophobicity of the grafted HDTMS chains was considered to be responsible for reducing the water droplet adsorption on the membrane surface.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·1831-1837
·
IF 4.831
Yang Zhen,Liu Yan,Lei Chong,Sun Xue-cheng,Zhou Yong
We report on a method for ultrasensitive detection and quantification of the pathogen Escherichia coli ( E. coli ), type O157:H7. It is using a tortuous-shaped giant magnetoimpedance (GMI) sensor in combination with an open-surface microfluidic system coated with a gold film for performing the sandwich immunobinding on its surface. Streptavidin-coated super magnetic Dynabeads were loaded with biotinylated polyclonal antibody to capture E. coli O157:H7. The E. coli -loaded Dynabeads are then injected into the microfluidics system where it comes into contact with the surface of gold nanofilm carrying the monoclonal antibody to form the immunocomplex. As a result, the GMI ratio is strongly reduced at high frequencies if E. coli O157:H7 is present. The sensor has a linear response in the 50 to 500 cfu·mL −1 concentration range, and the detection limit is 50 cfu·mL −1 at a working frequency of 2.2 MHz. In our perception, this method provides a valuable tool for developing GMI-based microfluidic sensors systems for ultrasensitive and quantitative analysis of pathogenic bacteria. The method may also be extended to other sensing applications by employing respective immunoreagents.
Fig. (a) Graphical illustration of the test setup. (b) Relationship of GMI signal vs. E. coli O157:H7 concentration.
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Scientific Reports
·
2017
·Vol. 7
·期 1
·1-10
·
IF 4.259
Tang Lina,Li Yutao,Xie Hui,Shu Qing,Yang Fan,Liu Yan-ling,Liang Fengxia,Wang Hua,Huang Weihua,Zhang Guo-Jun
This study reports an acupuncture needle modified with an iron-porphyrin functionalized graphene composite (FGPC) for real-time monitoring of nitric oxide (NO) release in acupoints of rats. A gold film was first deposited to the needle surface to enhance the conductivity. The FGPC was prepared via hydrothermal synthesis, and subsequently applied to the tip surface of acupuncture needle by electrochemical deposition method. The functionalized needle enabled a specific and sensitive detection of NO based on the favorably catalytic properties of iron-porphyrin and the excellent conductivity of graphene. Amperometric data showed that the needle achieved not only a low detection limit down to 3.2 nM in PBS solution, but also a satisfactory selectivity. Interestingly, the functionalized needle could be inserted into the acupoints of rats for real-time monitoring of NO in vivo . It was found that a remarkable response to NO was respectively obtained in different acupoints when stimulated by L -arginine ( L -Arg), revealing that the release of NO was detectable in acupoints. We expect this work would showcase the applications of acupuncture needle in detecting some important signaling molecules in vivo , and exploring the mechanism of acupuncture treatment.
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AAPS PHARMSCITECH
·
2017
·Vol. 18
·期 8
·3227-3235
·
IF 2.451
Wang Aoke,Ahmad Aftab,Ullah Sadeeq,Cheng Li,Ke Lin,Yuan Qipeng
Liposomes, the biocompatible lipid bilayer vesicles, have attracted immense attention due to their distinctive features such as efficient vehicle for the delivery of a wide range of therapeutic agents, adjustable formulation properties, and high drug entrapment efficiency. In this contribution, we present a simple method for the preparation of liposomes using glass beads and compared the potential of this method with conventional methods of liposome preparation. The prepared liposomes were characterized by different analytical techniques (HPLC, DLS, TEM, differential scanning calorimetry, and in vitro drug release). Our findings revealed that the particle size of liposomes is mainly dependent on the size of the glass beads and the glass bead shearing time. An average liposome size of 67.7 ± 25.5 nm was obtained using 2-mm glass beads after 24-h incubation at 200 rpm. The liposomes prepared under the optimized conditions exhibited a high encapsulation efficiency of 92.1 ± 1.7% with 31.08% drug release after 360 min at 37°C. In conclusion, the developed method is a simple and convenient process of liposome preparation of different sizes with desirable entrapment efficiency capacity.
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Journal of Inorganic and Organometallic Polymers and Materials
·
2017
·Vol. 27
·期 2
·586-597
·
IF 1.577
Wei Mei-hua,Chen Hong-yan,Wang Shu,Jiang Wan-ying,Wang Yi,Wu Zhang-feng
A ferulic acid molecularly imprinted membrane (MIM) with blending SiO 2 nanoparticles was constructed using photoinitiated copolymerization. The MIMs were synthesized using ferulic acid as template, 2,2-azobisisobutyronitrile (AIBN) as functional monomer, Ethylene glycol dimethacrylate (EGDMA) as crosslinker. The synthetic conditions such as the mass content and size of the SiO 2 nanoparticles and the UV exposure times were optimized to obtain the membrane with superior performance. The scanning electron microscope (SEM) and FT-IR Spectrometer had been used to visualize the structure morphology of the molecularly imprinted membrane and to quantity pore size and the surface characteristics. The recognition properties of all prepared membranes were thoroughly investigated by using the cross flow membrane filtration equipment to calculate the selectivity factor and the water flux. Results indicated that the ferulic acid composite MIM which with 0.25 wt% SiO 2 nanoparticles and 130–140 min exposure time were founded be optimum parameters. It showed good recognition ability to ferulic acid as well as high hydrophilicity and outstanding mechanical strength.
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CHEMICAL PAPERS
·
2017
·Vol. 71
·期 5
·895-904
·
IF 1.258
Wang Jun,Ma Li-Li,Song Lei,Wang Si-Han,Huo Hong-Liang,Li Cui-Qin
Three dendritic nickel complexes C1 – C3 were synthesized from three poly(amido amine) dendrimers, salicylic aldehyde and nickel chloride hexahydrate via Schiff base condensation reaction and coordination reaction. The structures of the dendritic ligands and nickel complexes were characterized by FT-IR, UV, 1 H NMR, ESI–MS, and elemental analysis. When activated with aluminum co-catalysts, three complexes C1 – C3 were able to catalyze ethylene oligomerization. The catalytic activities and the product distribution of complexes C1 – C3 were depended on the reaction parameter, co-catalyst, solvent, and the structure of the pre-catalyst. When using ethyl aluminum sesquichloride (EASC) as co-catalyst in toluene, the catalytic activity of complex C3 containing the longest bridging methylene groups reached the highest value of 1.63 × 10 6 g·(mol Ni·h) −1 with 69.15% C 11 in the product at 30 min, 25 °C, 0.5 MPa, and Al/Ni ratio of 900.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2017
·Vol. 130
·期 2
·935-941
·
IF 1.953
Han Lipeng,Ma Guixiang,Xie Shaolei,Sun Jinhe,Jia Yongzhong,Jing Yan
Shape-stabilized composite phase change materials composed of sebacic acid (SA) and MCM-41 were prepared by a facile blending and impregnating method. Various characterization techniques were carried out to characterize their structural and thermal properties, including thermogravimetry (TG) analyses and differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy. The XRD and FT-IR results indicated the interactions between SA and MCM-41, such as the capillary force and the hydrogen bonding, resulting in the confined crystallization process. As a result, the SA that was confined was amorphous. The TG analysis results showed that the presence of MCM-41 practically resulted in an overlapping of the two decomposition stages. The DSC analysis demonstrated that a decrease in the SA content was accompanied by a continuous decrease in the melting point and phase change enthalpy of the composites.
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