Search

We report a new strategy to fabricate a multifunctional composite photoanode containing TiO2 hollow spheres (TiO2‐HSs), Au nanoparticles (AuNPs) and novel NaYF4 : Yb,Er@NaLuF4 : Eu@SiO2 upconversion nanoparticles (UCNPs). The AuNPs are grown on the photoanode film including TiO2‐HSs and UCNPs by a simple in situ plasmonic treatment. As a result, an impressive power conversion efficiency of 14.13 % is obtained, which is a record for N719 dye‐based dye‐sensitized solar cells, demonstrating great potential for the solar cells toward commercialization. This obvious enhancement is ascribed to a collaborative mechanism of the TiO2‐HSs exhibiting excellent light‐scattering ability, of the UCNPs converting near‐infrared photons into visible photons and of the AuNPs presenting outstanding surface plasmon resonance effect. Notably, a steady‐state experiment further reveals that the champion cell exhibits 95.33 % retainment in efficiency even after 180 h of measurements, showing good device stability. [ABSTRACT FROM AUTHOR]

Studying the influence of electric field on the icing process of insulators with various dielectric surfaces is of great importance to the design of external insulation. This study established a finite element model to simulate the distribution of electric field around various insulator strings. Energised and non‐energised icing tests were conducted to obtain the influence rules of electric field on the insulator icing process. The results of water droplets freeze experiment provided microscopic explanation of icing tests. Research results indicate that electric field and surface dielectrics have influence on the appearance, density and mass of ice on insulators. In microcosmic view, water droplets on super‐hydrophobic surface correspond to longer freezing time and smaller average diameters, which leads to the better anti‐icing character of super‐hydrophobic insulator. Different types of ice branches appear in the water droplets freezing process on various dielectric surfaces. Owing to the polarisation effect, electric field can inhibit the formation and growth of ice branch, which contributes to different anti‐icing characters of various dielectric surfaces in electric field. The effect of dielectric surface on insulator icing process mainly act at the initial period, surface coatings of insulators are not suggested to be applied in heavily icing area. [ABSTRACT FROM AUTHOR]

Hedgehog ( Hh) pathway has been studied in various animal body life procedures and is suggested to be important for the development of multiple organs. The genes involved in the Hh signaling pathway were expressed in the ovary of mice, pigs and cattle. However, the function of Hh signaling pathway on oocyte maturation and early embryonic development is still controversial. We detected the effect of sonic hedgehog ( Shh) and cyclopamine on the in vitro maturation of mouse oocytes and embryo development. The results showed that the presence of Shh or cyclopamine resulted in similar oocyte maturation to control groups. Shh did not improve early embryonic development. However, the supplement of cyclopamine depressed early embryo development. The mRNA of shh, ptch1, smo and gli1 were less detected in the denuded oocytes. The expression levels of ptch1 ascended from the uncleaved zygote to blastocyst stage. Smo or gli1 were expressed on a higher level at the two-cell or four-cell stage in early embryonic development separately. Therefore, Shh did not affect mouse oocyte maturation and early embryo development, but cyclopamine led to inhibited development of mouse early embryo. The effects of Hh signaling on the oocyte maturation and early embryo development might be species-specific. [ABSTRACT FROM AUTHOR]

As membrane transporter proteins, VGLUT1-3 mediate the uptake of glutamate into synaptic vesicles at presynaptic nerve terminals of excitatory neural cells. This function is crucial for exocytosis and the role of glutamate as the major excitatory neurotransmitter in the central nervous system. The three transporters, sharing 76% amino acid sequence identity in humans, are highly homologous but differ in regional expression in the brain. Although little is known regarding their three-dimensional structures, hydropathy analysis on these proteins predicts 12 transmembrane segments connected by loops, a topology similar to other members in the major facilitator superfamily, where VGLUT1-3 have been phylogenetically classified. In this work, we present a three-dimensional model for the human VGLUT1 protein based on its distant bacterial homolog in the same superfamily, the glycerol-3-phosphate transporter from Escherichia coli. This structural model, stable during molecular dynamics simulations in phospholipid bilayers solvated by water, reveals amino acid residues that face its pore and are likely to affect substrate translocation. Docking of VGLUT1 substrates to this pore localizes two different binding sites, to which inhibitors also bind with an overall trend in binding affinity that is in agreement with previously published experimental data. [ABSTRACT FROM AUTHOR]

Here we report the successful three-dimensional crystallization of GlpT, the glycerol-3-phosphate transporter from Escherichia coli inner membrane. GlpT possesses 12 transmembrane α-helices and is a member of the major facilitator superfamily. It mediates the exchange of glycerol-3-phosphate for inorganic phosphate across the membrane. Approximately 20 phospholipid molecules per protein, identified as negatively charged phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin, were required for the monodispersity of purified GlpT. Analytical size-exclusion chromatography proved to be efficient in identifying detergents for GlpT monodispersity. Nine such detergents were later used for GlpT crystallization. Screening for crystal nucleation was carried out with a variety of polyethylene glycols as the precipitant over a wide pH range. Subsequent identification of a rigid protein core by limited proteolysis and mass spectroscopy resulted in better-ordered crystals. These crystals exhibited order to 3.7 Å resolution in two dimensions. However, the stacking in the third dimension was partially disordered. This stacking problem was overcome by using a detergent mixture and manipulating the ionic interactions in the crystallization solution. The resulting GlpT crystals diffracted isotropically to 3.3 Å resolution and were suitable for structure determination by X-ray crystallography. [ABSTRACT FROM AUTHOR]