Mimicking the cell membrane with block copolymer membranes

Cell membranes are essential barriers in Nature. To understand their properties and functions and to develop desirable applications, a simple and elegant approach is to study membranes that mimic the cell membrane. Lipid bilayers represent simple models that are physiologically representative when in the form of mixtures of various lipids, but they are not adequately stable even when covered with amphipathic proteins or when combined with polymers, thus preventing technological applications. This makes necessary the design of completely synthetic membranes. In this respect, amphiphilic copolymers that self‐assemble under dilute aqueous conditions and generate supramolecular polymer vesicles or films are ideal candidates for synthetic membranes. Their versatility in terms of chemistry and properties (permeability, mechanical stability, thickness), if appropriately designed, enable the insertion of biological molecules, such as membrane proteins and biopores, or the attachment of biomolecules at their surfaces. Here, we present the domain of synthetic membranes based on amphiphilic copolymers beginning with their generation and up to their applications in medicine, the food industry, and technology. Even though significant progress has been made in combining them with membrane proteins, open questions remain with respect to desired properties that could accommodate biological molecules and support further development of the field, from both the point of view of fundamental understanding and of applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Pharmacokinetic comparison of five tanshinones in normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan or its single herb extract by UPLC‐MS/MS

A fast, sensitive and reliable ultra performance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS) method has been developed and validated for simultaneous quantitation and pharmacokinetic study of five tanshinones (tanshinone I, tanshinone IIA, tanshinone IIB, dihydrotanshinone I, cryptotanshinone), the bio‐active ingredients of Huo Luo Xiao Ling Dan (HLXLD) in rat plasma. After liquid–liquid extraction, chromatographic separation was accomplished on a Shim‐pack XR‐ODS column (75 × 3.0 mm, 2.2 µm particles) and eluted with a mobile phase consisting of acetonitrile–0.05% formic acid aqueous solution (80:20, v/v) at a flow rate of 0.4 mL/min, and the total run time was 7.0 min. The detection was performed on a triple quadrupole tandem mass spectrometry equipped with an electrospray ionization source in positive ionization and multiple reaction monitoring mode. The lower limits of quantification were 0.050–0.400 ng/mL for all the analytes. Linearity, precision and accuracy, the mean extraction recoveries and matrix effects all satisfied criteria for acceptance. This validated method was successfully applied to a comparative pharmacokinetic study of five bio‐active components in rat plasma after oral administration of HLXLD or Salvia miltiorrhiza extract in normal and arthritic rats. The results showed that there were different pharmacokinetic characteristics among different groups. Copyright © 2016 John Wiley & Sons, Ltd.     

Core–shell CeO2 micro/nanospheres prepared by microwave-assisted solvothermal process as high-stability anodes for Li-ion batteries

Journal of Solid State Electrochemistry - Core–shell CeO2 micro/nanospheres are prepared via microwave-assisted solvothermal process followed by calcination in air. The reaction time is only...     

Orientation-dependent deformation mechanisms of bcc niobium nanoparticles

Nanoparticles usually exhibit pronounced anisotropic properties, and a close insight into the atomic-scale deformation mechanisms is of great interest. In present study, atomic simulations are conducted to analyse the compression of bcc nanoparticles, and orientation-dependent features are addressed. It is revealed that surface morphology under indenter predominantly governs the initial elastic response. The loading curve follows the flat punch contact model in [1 1 0] compression, while it obeys the Hertzian contact model in [1 1 1] and [0 0 1] compressions. In plastic deformation regime, full dislocation gliding is dominated in [1 1 0] compression, while deformation twinning is prominent in [1 1 1] compression, and these two mechanisms coexist in [0 0 1] compression. Such deformation mechanisms are distinct from those in bulk crystals under nanoindentation and nanopillars under compression, and the major differences are also illuminated. Our results provide an atomic perspective on the mechanical behaviours of bcc nanoparticles and are helpful for the design of nanoparticle-based components and systems.     

Potential influence on drug efficacy from interaction of tartrazine and trypsin

The extent to which drugs combine with trypsin is influenced by the interaction of tartrazine and trypsin, which may cause overdose or underdose of drugs. Therefore, the interaction of tartrazine and trypsin is investigated by methods of spectrometry in this paper. The binding rate of tartrazine to trypsin is 80.95–95.71% at 310?K, and Hill’s coefficients are almost 1. The effect of tartrazine on trypsin structure was studied by synchronous and circular dichroism. The results showed that the binding of tartrazine and trypsin induced the conformational change of trypsin, and quenched the endogenous fluorescence in trypsin. The results of molecular docking revealed that tartrazine is located in the catalytic active site of trypsin, and is consistent with that of experimental calculation.     

Effective contrast enhancement method for color night vision

Image fusion refers to the techniques that integrate complementary information from multiple image sensors’ data in a way that makes the new images more suitable for human visual perception. The paper focuses on the low color contrast problem of linear fusion algorithms with color transfer method. Firstly, the contrast of infrared and visible images is enhanced using local histogram equalization and median filter. Then the two enhanced images are fused into the three components of a Lab image in terms of a simple linear fusion strategy. To enhance the color contrast between the target and the background, the scaling factor is introduced into the transferring equation in the b channel. Experimental results based on three different data sets show that the hot and cold targets are all popped out with intense colors while the background details present natural color appearance. Target detection experiments through target recognition area, detection rate, target-background discrimination also show that the presented method has a better performance than the former methods.