Internalization and Accumulation in Dendritic Cells of a Small pH‐Activatable Glycomimetic Fluorescent Probe as Revealed by Spectral Detection

DC‐SIGN, an antigen‐uptake receptor in dendritic cells (DCs), has a clear role in the immune response but, conversely, can also facilitate infection by providing entry of pathogens into DCs. The key action in both processes is internalization into acidic endosomes and lysosomes. Molecular probes that bind to DC‐SIGN could thus provide a useful tool to study internalization and constitute potential antagonists against pathogens. So far, only large molecules have been used to directly observe DC‐SIGN‐mediated internalization into DCs by fluorescence visualization. We designed and synthesized an appropriate small glycomimetic probe. Two particular properties of the probe were exploited: activation in a low‐pH environment and an aggregation‐induced spectral shift. Our results indicate that small glycomimetic molecules could compete with antigen/pathogen for binding not only outside but also inside the DC, thus preventing the harmful action of pathogens that are able to intrude into DCs, for example, HIV‐1.     

Investigation on structure and properties of anion exchange membranes based on tetramethylbiphenol moieties containing copoly(arylene ether)s

Quaternary ammonium functionalized poly(arylene ether)s (QPAEs) containing 2,2′,6,6′‐tetramethylbiphenol moieties were designed and successfully synthesized via nucleophilic substitution polycondensation, bromination, quaternization and alkalization. The structure, water uptake, ion exchange capacities (IECs), hydroxide ion conductivities, and mechanical properties, as well as thermal and chemical stabilities of obtained QPAEs membranes were investigated. The QPAE‐a membrane with IEC value of 0.98 meq g^?1 demonstrated the highest ion conductivity (47.4 mS cm^?1) at 80°C. The ion transport activation energy (E_a) of QPAEs membranes varied from 8.57 to 19.95 kJ mol^?1. After chemical stability test conditioned in 1M NaOH at 60°C for 7 days, the QPAEs membranes except QPAE‐c (IEC = 0.88 meq g^?1) still exhibited high hydroxide ion conductivities (over 15 mS cm^?1) and acceptable tensile strength (～10 MPa). These properties indicate that the ionomers membranes are potential candidates for anion exchange membranes in anion exchange membrane fuel cells. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41525.     

A facile synthesis of a novel three‐phase nanocomposite: Single‐wall carbon nanotube/silver nanohybrid fibers embedded in sulfonated polyaniline

A three‐phase water‐soluble nanocomposite of single wall carbon nanotube/silver nanoparticle hybrid fibers embedded in sulfonated polyaniline has been synthesized by a simple chemical solution mixing process. The nanocomposite has been characterized by high resolution electron microscopy, X‐ray diffractometry, FTIR spectroscopy, Raman spectroscopy, and thermogravimetric analysis. Optical and electrical characteristics of the nanocomposite have been determined by UV–vis absorption spectroscopy, photoluminescence spectroscopy, and four‐probe electrical conductivity measurement. A surface plasmon absorption band obtained around 460 nm indicates the presence of silver nanoparticles in the composite. The optical band gap calculation for sulfonated polyaniline vis‐a‐vis the nanocomposite supported the conductivity measurement. Over 1300 times increase in DC electrical conductivity has been observed for the three‐phase nanocomposite, with a filler loading of 20 wt %, at 306 K. This observation could be explained by Mott's variable range hopping model considering a three‐dimensional conduction. Such a nanocomposite has immense potential for use as a cathode material in lithium‐ion batteries and supercapacitors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41692.     

Orthogonal design study on factors affecting the diameter of perfluorinated sulfonic acid nanofibers during electrospinning

In this study, Nafion® NR 40 beads with polyethylene oxide (PEO) are fabricated into a nanofiber membrane using electrospinning. In particular, Nafion® beads in non‐toxic mixed solvent (EtOH and H₂O) were blended with the carrier polymer PEO, which is the minor component in the solution responsible for the solution spinnability. The highest content of Nafion® in the nanofiber is 98.04%. To investigate the factors influencing the nanofiber diameter during electrospinning, an orthogonal design method was adopted. These factors include the carrier polymer content, distance between the syringe needle and roller collector, flow rate of the electrospinning solution, and the roller rotation speed. After obtaining the significant factors and optimal test level, an additional optimization experiment is conducted under the best conditions. The resulting nanofibers have a diameter of ～150 nm. Moreover, the obtained Nafion® nanofiber membrane has strong potential for applications in polymer electrolyte membrane fuel cells (PEMFC), the chlor‐alkali industry, catalysts, and metal ion removal. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41755.     

光解水制氢催化剂的研究进展

面对人类对能源的需求持续增长以及化石能源的日益枯竭和其带来的环境污染问题,开发太阳能对于解决能源问题具有非常重要的意义。利用太阳能分解水制氢是一种将太阳能转换为氢能的有效方式。根据近年来国内外太阳能分解水制氢催化剂的研究现状,分别对半导体光催化剂和金属配合物光催化剂进行综述,并且从可持续发展和实际应用的角度出发,针对各自的优缺点,提出今后应该开发具有高效且成本低廉的非贵金属配合物光催化剂,或尝试与半导体光催化剂结合应用,提高制氢效率。     

Imidazole/(HPO3)3‐doped sulfonated poly (ether ether ketone) composite membrane for fuel cells

A novel gel of imidazole/(HPO₃)₃ was synthesized and incorporated into sulfonated poly (ether ether ketone) (SPEEK) to fabricate composite proton exchange membranes. The composite membranes were characterized by alternating current impedance (AC), thermogravimetry (TG), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), scanning electron microscope (SEM) and mechanical property test. Based on the electrochemical performance investigation, the proton conductivity of the membrane is intimately correlated with the temperature and the mass ratio of imidazole/(HPO₃)₃ in the composite. The SPEEK/imidazole/(HPO₃)₃?4 composite membrane (with 44.4 wt % of imidazole/(HPO₃)₃) has the optimized performance at 135°C. Mover, the strength of the composite membranes is almost comparable to that of Nafion membrane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41946.     

Synthesis,characterization, and ceramization of a carbon-rich SiCw-ZrC-ZrB2 preceramic polymer precursor

A precursor (PBSZ) for SiC_w-ZrC-ZrB₂ hybrid powder was synthesized by chemical reaction of phenol, paraformaldehyde, zirconium oxychloride, boric acid and tetraethylorthosilicate. Results show that zirconium, silicon and boron atoms have been successfully introduced into the branched structure. Decomposition of PBSZ is completed at 800 °C, and it gives amorphous carbon, SiO₂, B₂O₃ and ZrO₂ with a yield of 38% at 1200 °C. During the pyrolysis process, ZrB₂ and SiC form at about 1500 °C, followed by the appearance of ZrC when the amount of B₂O₃ is limited. Highly crystallized ZrB₂–ZrC–C powder with ZrB₂ and ZrC grains evenly distributed in the carbon matrix together with randomly distributed SiC whiskers are obtained after heat-treated at 1800 °C. Further heated at 1900 °C, ZrB₂ and ZrC grains grow from 200 to 500 nm, while SiC whiskers show a much smaller diameter size and tend to grow on the ZrB₂–ZrC–C block surface. The morphology difference is caused by the larger gas supersaturation and accommodation coefficient of the pore channels on the block surface. In addition, defects of the carbon matrix are cumulated to the highest at 1500 °C and the structure-ordered carbon is obtained after heat treated at 1900 °C.     

Copper-based electrodes for IT-SOFC

Copper and gadolinium doped ceria (GDC) anode supported fuel cells were co-sintered at relatively low temperature (900 °C) and successfully tested in the intermediate temperature (IT) range. The GDC electrolyte densification was promoted by a compressive strain induced by increasing the anodic thickness and was evaluated by SEM investigation. Instead of more commonly used La_0.8Sr_0.2Fe_0.6Co_0.4O_3-δ, strontium and copper-doped lanthanum ferrite La_0.8Sr_0.2Fe_0.8Cu_0.2O_3-δ (LSFCu) mixed with 30 wt% GDC (LSFCu-GDC) was employed as cathodic material. Preliminary tests on Cu-GDC/GDC/LSFCu-GDC single cells showed promising results at temperature as low as 650 °C using hydrogen as fuel.     

Non-destructive 3-dimensional mapping of microcapsules in polymeric coatings by confocal Raman spectroscopy

Nowadays, the properties of polymeric coatings are enhanced by various additives mixed into the resin. Recently, embedding of polymeric microcapsules into the coating matrix has been investigated to provide special on-demand features to the coating. The detection and characterization of such microcapsules in a polymeric coating are of major importance but difficult, because both are built up by similar molecules with similar densities. Current analysis methods require complex sample preparation to allow reliable measurements.In contrast, confocal Raman spectroscopy allows fast and non-destructive differentiation between characteristic molecular bonds at a spatial resolution below one micrometer. Hence, the objective of this research was to apply this technique on microcapsules embedded in a coating and provide answers to the following questions: Can one detect microcapsules embedded in a coating and clearly identify them? Can one differentiate between full and empty microcapsules and the coating matrix? Can one determine the exact location of the capsules and their distribution in the coating?Therefore, several two-dimensional confocal Raman spectroscopy mappings recorded at different depths allowed a three-dimensional reconstruction of the polymeric coating with the polymeric microcapsules in it. Thereby, the distribution of the capsules within the coating could be determined with micrometer resolution. As a result Raman tomography provides a more detailed insight into the distribution of microcapsules through the possibility of three-dimensional reconstruction.     

Nonlinear model predictive control of an industrial polymerization process

Nonlinear model predictive control (NMPC) is used to maintain and control polymer quality at specified production rates because the polymer quality measures have strong interacting nonlinearities with different temperatures and feed rates. Polymer quality measures that are available from the laboratory infrequently are controlled in closed-loop using a NMPC to set the temperature profile of the reactors. NMPC results in better control of polymer quality measures at different production rates as compared to using the nonlinear process model with reaction kinetics to implement offline targets for reactor temperatures.