Stability of hydrogen incorporated in ZnO nanowires by plasma treatment

The stability of hydrogen in ZnO is studied using hydrogenated nanowires by plasma treatment. Enhanced near band edge UV emission and reduced defect level green emission is observed after hydrogen plasma treatment. Through thermal stability tests, this effect is found to be stable at room temperature and nearly stable up to ~500 K, but begins to deteriorate at higher temperature. The study of the irradiation stability of the hydrogen in ZnO nanowires shows that the hydrogen is stable under an electron beam with an accelerating voltage lower than 5 kV, but is not stable under 10 kV or under an intensive laser beam. The results could benefit the further understanding of the role of hydrogen in ZnO and light-emitting devices based on hydrogenated ZnO.     

Effects of landscape structure on vegetation and some animal groups after agriculture abandonment

This research was carried out on the montane belt of a south-exposed watershed in the Intermediary Alps which have been hit by agriculture abandonment. The aim of the study was to study the relationships between vegetation, landscape mosaic, and two kinds of animals using this space at different scales: roe deer (Capreolus capreolus) and earthworms (lumbricids). Landscape dynamics (post-cultural recolonisation) and landscape structure have been approached by means of the Arc/Info geographical information system (GIS). Several methods used to study on one hand roe deer distribution, and, on the other, earthworm abundance and diversity are developed. Of these, in particular, GIS processing is used to sample earthworms according to vegetation dynamics, and roe deer distribution is related to landscape heterogeneity. Earthworms are more abundant and diversified in the key steps of vegetation dynamics. These lumbricids can be considered as functional indicators of these dynamics. Results also demonstrate that both the vegetation type and the landscape heterogeneity have a direct influence on the use of the space by the roe deer. They show themselves to be structural indicators of the landscape.     

Stability Is Not Everything: The Case of the Cyclisation of a Thrombin-Binding Aptamer

With the aim of developing a new approach to obtain improved aptamers, a cyclic thrombin-binding aptamer (TBA) analogue (cycTBA) has been prepared by exploiting a copper(I)-assisted azide–alkyne cycloaddition. The markedly increased serum resistance and exceptional thermal stability of the G-quadruplex versus TBA were associated with halved thrombin inhibition, which suggested that some flexibility in the TBA structure was necessary for protein recognition.     

Modified Galacto- or Fuco-Clusters Exploiting the Siderophore Pathway to Inhibit the LecA- or LecB-Associated Virulence of Pseudomonas aeruginosa

Galacto- and fuco-clusters conjugated with one to three catechol or hydroxamate motifs were synthesised to target LecA and LecB lectins of Pseudomonas aeruginosa (PA) localised in the outer membrane and inside the bacterium. The resulting glycocluster–pseudosiderophore conjugates were evaluated as Trojan horses to cross the outer membrane of PA by iron transport. The data suggest that glycoclusters with catechol moieties are able to hijack the iron transport, whereas those with hydroxamates showed strong nonspecific interactions. Mono- and tricatechol galactoclusters ( G1C and G3C ) were evaluated as inhibitors of infection by PA in comparison with the free galactocluster ( G0 ). All of them exhibited an inhibitory effect between 46 to 75 % at 100 μM, with a higher potency than G0 . This result shows that LecA localised in the outer membrane of PA is involved in the infection mechanism.     

Highly efficient electrocatalysts fabricated via electrophoretic deposition for alcohol oxidation,oxygen reduction,hydrogen evolution,and oxygen evolution reactions

Electrophoretic deposition (EPD) is a versatile technique that has drawn attention due to its ease of use and performance in depositing high-quality layers at room temperature. This technique principle is based on the deposition of charged particles from a stable colloidal suspension on a conductive substrate using either a direct or alternating current. Using relatively simple and low-cost equipment, the EPD technique enables the deposition of layers with controlled microstructures at nanoscale. The EPD technique has been particularly successful in the fabrication of the electrocatalyst layers for low-temperature fuel cells, which are anchored on the top of the fuel cell electrodes. In comparison with other electrocatalyst layer deposition techniques such as drop-casting, the EPD technique offers clear advantages for the control of the thickness and packing density of the electrocatalyst layers. Owing to the dense packing density, electrocatalyst layers deposited by EPD could achieve enhanced conductivity and efficiency. The present review aims at comprehensively evaluating the recently published results on the electrocatalyst layers fabricated by EPD and applied in oxygen reduction reactions, alcohol electro-oxidation reactions, hydrogen evolution reactions, and oxygen evolution reactions.     

Metallic Nanowire Coupled CsPbBr3 Quantum Dots Plasmonic Nanolaser

Plasmonic nanolasers provide a valuable opportunity for expanding sub-wavelength applications. Due to the potential of on-chip integration, semiconductor nanowire (NW)-based plasmonic nanolasers that support the waveguide mode attract a high level of interest. To date, perovskite quantum dots (QDs) based plasmonic lasers, especially nanolasers that support plasmonic-waveguide mode, are still a challenge and remain unexplored. Here, metallic NW coupled CsPbBr₃ QDs plasmonic-waveguide lasers are reported. By embedding Ag NWs in QDs film, an evolution from amplified spontaneous emission with a full width at half maximum (FWHM) of 6.6 nm to localized surface plasmon resonance (LSPR) supported random lasing is observed. When the pump light is focused on a single Ag NW, a QD-NW coupled plasmonic-waveguide laser with a much narrower emission peak (FWHM = 0.4 nm) is realized on a single Ag NW with the uniform polyvinylpyrrolidone layer. The QDs serve as the gain medium while the Ag NW serves as a resonant cavity and propagating plasmonic lasing modes. Furthermore, by pumping two Ag NWs with different directions, a dual-wavelength lasing switch is realized. The demonstration of metallic NW coupled QDs plasmonic nanolaser would provide an alternative approach for ultrasmall light sources as well as fundamental studies of light matter interactions.