The adsorption on hydrophobic and hydrophilic silica-based surfaces of the integrin-binding PHSRN peptide and the single-residual-mutated analogues, PHSEN and PHSFN, is investigated by comparative QCM-D, XPS, SFG measurements and molecular dynamics calculations. Endothelial cell cultures on the peptide-functionalized materials highlight their tunable pro- or anti-angiogenic potential

We have followed a 'molecular' approach to study impurity effects in graphene. This is thought as the limiting case of an infinitely large cluster of benzene rings. Therefore, we study several carbon clusters, with increasing size, from phenalene, including three benzene rings, up to coronene 61, with 61 benzene rings. The impurities considered were a chemisorbed H atom, a vacancy, and a substitutional proton. We performed HF and UHF calculations using the STO-3G basis set. With increasing cluster size in the absence of impurities, we find a decreasing energy gap, here defined as the HOMO-LUMO difference. In the case of H chemisorption or a vacancy, the gap does not decrease appreciably, whereas it is substantially reduced in the case of a substitutional proton. The presence of an impurity invariably induces an increase of the density of states near the HOMO level. We find a zero mode only in the case of a substitutional proton. In agreement with experiments, we find that both the chemisorbed H, the substitutional proton, and the C atom near a vacancy acquire a magnetic moment. The relevance of graphene clusters for the design of novel electronic devices is also discussed.

This contribution explores the effect of the 1,2-diimine bridge upon the Lewis acidic character of a series of bis(salicylaldiminato)zinc(ii), ZnL, Schiff-base complexes. The structure of the monomeric and dimeric ZnL complexes, and of the 1 : 1 adducts with pyridine, ZnL·py, is fully optimized by means of DFT calculations. The Gibbs free energy for the dimerization of ZnL complexes and for the formation of ZnL·py adducts is evaluated by accurate composite calculations. It accounts for their spontaneous dimerization and for the greater stability of the ZnL·py adducts with respect to the dimers. Calculated binding constants for the formation ZnL·py adducts are in excellent agreement with experimentally derived values, thus allowing establishing a relative Lewis acidity scale within this series. While the complex derived from the non-conjugated ethylenediamine reveals the lowest Lewis acidity, the complex derived from the diaminomaleonitrile represents the stronger Lewis acidic species. These findings are in good agreement with the greater catalytic activity observed for ZnL Schiff-base complexes derived from conjugated 1,2-diamines in comparison to the non-conjugated analogues. Both in ZnL dimers as well as in ZnL·py adducts the geometry of the coordination sphere seems to be a relevant feature to assess their relative stability. Thus, while the quasi-planarity of ZnL monomers of the conjugated diimines is an unfavourable feature in the dimerization process, it represents an important aspect in stabilizing ZnL·py adducts in a nearly perfect square-pyramidal coordination. These features are relevant for the sensing and catalytic properties of these complexes.

• . The received power presents a clearly multimodal behavior, which also suggests that the coherent scattering component may be taking place in different forest elements, i.e., soil, canopy, and through multiple reflections canopy-soil and soil-trunk. This experiment has provided the first GNSS-R data set over boreal forests. The evaluation of these results can be useful for the feasibility study of this technique to perform biomass monitoring that is a key factor to analyze the carbon cycle.Index Terms-Boreal forests, global navigation satellite systems reflectometry (GNSS-R), stratospheric balloon.