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Abstract: The conserved armadillo repeat (ARM) domain of adenomatous polyposis coli (APC) protein plays an important role in the recognition of its binding partners. In this study, we report the crystal structure of APC-ARM (residues 407-775), which was determined to 2.9Å resolution. Our structure shows that the seven armadillo repeats of APC-ARM fold together into a compact domain, with Arm2 and Arm5 presenting some deviations from canonical armadillo repeats. There is a positively charged groove on the surface of APC-ARM, which might be the recognition site for APC-binding partners. Comparison of this structure with our previously reported structure of APC (407-751), together with normal mode analysis, reveals that the APC-ARM domain possesses a limited intrinsic flexibility. We propose that this intrinsic flexibility might be an inherent property of ARM domains in general. [Copyright &y& Elsevier]

Abstract: In this work, V-doped TiO2 nanofibers with different V contents have been fabricated by an electrospinning technique. The as-prepared nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), and UV–Vis diffuse reflectance (DR) spectroscopy. The results indicated that the V4+ or V5+ ions were successfully incorporated into the crystal lattice of anatase TiO2 nanofibers. Meanwhile, the V doping could extend the visible light absorption of TiO2 nanofibers. The photocatalytic experiments indicated that the obtained V-doped TiO2 nanofibers possessed high activity for the photodegradation of organic pollutant methylene blue (MB). Especially, the 1.0 and 5.0wt.% V-doped TiO2 nanofibers exhibited the best catalytic activity under visible and ultraviolet (UV) light irradiation, respectively. Also, these nanofibers could be easily recycled without a decrease of the photocatalytic activity. [Copyright &y& Elsevier]

Abstract: Highly dispersed ZnO quantum dots (QDs) in poly(vinyl pyrrolidone) (PVP) nanofibers have been successfully prepared by electrospinning technique. The structure and optical properties were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), resonant Raman spectra, Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric and differential thermal analysis (TG–DTA), ultraviolet (UV)–vis absorption spectra, and photoluminescence (PL) spectra. In the PVP/ZnO QDs composite nanofibers, PVP molecules could effectively prevent the aggregation of ZnO QDs and passivate the surface defects of ZnO QDs. Thus, by comparing ZnO QDs, the composite nanofibers exhibited a blue-shifted band gap and enhanced ultraviolet (UV) emission. Furthermore, the composite nanofibers prepared at higher voltage showed more intense UV emission than which obtained at lower voltage, suggesting that the UV emission intensity of the composite nanofibers could be controlled by adjusting the electrospinning voltage. [Copyright &y& Elsevier]

Abstract: Tin oxide (SnO2)/carbon nanofibers (CNFs) heterostructures were fabricated by combining the versatility of the electrospinning technique and template-free solvent–thermal process. The results revealed that the SnO2 nanostructures were successfully grown on the primary electrospun carbon nanofibers substrates. And, the coverage density of SnO2 nanoparticles coating on the surface of the CNFs could be controlled by simply adjusting the mass ratio of CNFs to SnCl4·5H2O in the precursor during the solvent–thermal process for the fabrication of SnO2/CNFs heterostructures. The electrochemical performances of the SnO2/CNFs heterostructures as the electrode materials for supercapacitors were evaluated by cyclic voltammetry (CV) and galvanostatic charge–discharge measurement in 1M H2SO4 solution. At different scan rates, all the samples with different coverage densities of SnO2 showed excellent capacitance behavior. And, the sample CS2 (the mass ratio of CNFs to SnCl4·5H2O reached 1:7) exhibited a maximum specific capacitance of 187F/g at a scan rate of 20mV/s. Moreover, after 1000 cycles, the specific capacitance retention of this sample was over 95%. The high capacitive behavior could be ascribed to the low resistance of SnO2/CNFs heterostructures and rapid transport of the electrolyte ions from bulk solution to the surface of SnO2. [Copyright &y& Elsevier]