The catalytic hydrogenation of CO(2) at the surface of a metal hydride and the corresponding surface segregation were investigated. The surface processes on Mg(2)NiH(4) were analyzed by in situ X-ray photoelectron spectroscopy (XPS) combined with thermal desorption spectroscopy (TDS) and mass spectrometry (MS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). CO(2) hydrogenation on the hydride surface during hydrogen desorption was analyzed by catalytic activity measurement with a flow reactor, a gas chromatograph (GC) and MS. We conclude that for the CO(2) methanation reaction, the dissociation of H(2) molecules at the surface is not the rate controlling step but the dissociative adsorption of CO(2) molecules on the hydride surface.

The surface of human and bovine articular cartilage was imaged with environmental SEM and AFM. The effective modulus of the surface, from force-distance curves obtained with AFM, remained constant at 9±2 kPa in the presence of synovial fluid. Extensive washing of the cartilage surface with phosphate buffered saline (PBS) removed a superficial gel-like layer, leaving a granular layer intact. Force-distance curves showed that the chemical and mechanical properties of the gel exposed to PBS changed over time. The effective modulus at the surface dropped from 481 to 4 kPa over an hour. The results suggest that the gel-like layer, having partly lost water through evaporation on removal from the joint, absorbs water from PBS. It becomes softer and eventually begins to dissolve. The low effective modulus of the gel-like layer in synovial fluid indicates that it is too soft to influence the surface roughness. Imprints of the surface under pressure were taken using a low viscosity dental kit. Imaging of the imprint surface indicated that the topography of the cartilage under pressure was similar to that of the surface after removal of the gel-like layer. In conclusion, imaging of articular cartilage with ESEM and AFM revealed two distinct non-fibrous layers, which are granular and gel-like, and cover the fibrous collagen matrix.

Interactions in binary mixed monolayers from lipids 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and amphiphilic poly(2-methyloxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyloxazoline) block copolymers were studied by using the Langmuir balance technique and Brewster angle microscopy. It is shown that monolayers from the saturated lipid (DPPC) are more sensitive to the presence of polymers in the film, resulting in phase separation and the formation of pure lipid domains at high surface pressure. The morphology and composition of such phase-separated lipid-polymer films were studied by fluorescence microscopy and ToF-SIMS. In contrast, in DOPC-containing monolayers, the polymers tend to phase-separate at low surface pressures only and homogeneous films are obtained upon further compression, due to higher lipid fluidity. The analysis of excess energy of mixing shows that while the separation effect in densely packed DPPC-containing films is strongly dependent on the polymer size (with the larger polymer having a much stronger influence), in the case of monolayers with DOPC much smaller effects are observed. The results are discussed in terms of the monolayer composition, lipid fluidity, and polymer size.

A magnetically separable, recyclable gold catalyst consisting of gold nanoparticles supported on intimately mixed superparamagnetic ceria/iron oxide has been prepared by simple addition of the preformed mixed oxide support and the gold precursor, Au(OAc)3, to the reaction mixture of the aerobic oxidation of amines. The catalyst was characterized by means of X‐ray diffraction (XRD), N2 adsorption, superconducting quantum‐interference device (SQUID) measurements, time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), scanning transmission electron microscopy (STEM), and scanning electron microscopy with an energy‐dispersive X‐ray spectrometer (SEM‐EDAX). Catalytic tests with various amines showed high selectivity to the corresponding imines (87–100 %), and good separation efficiency and recyclability of the catalyst.

Treatment of osseoimplant surfaces with autologous platelet-rich plasma prepared according to the plasma rich in growth factors (PRGF-Endoret) protocol prior to implantation yields promising results in the clinic. Our objective is to understand the organization of complex interfaces between blood plasma preparations of various compositions and model titania surfaces. Here we present the results of the morphological and chemical characterization of TiO(2) surfaces incubated with four types of blood plasma preparations devoid of leukocytes and red blood cells: either enriched in platelets (PRGF-Endoret) or platelet-depleted, and either activated with CaCl(2) to induce clotting, or not. Chemical characterization was done by time-of-flight secondary ion mass spectrometry with principal component analysis (ToF-SIMS/PCA). The interface morphology was studied with scanning electron and atomic force microscopy. Immunofluorescence microscopy was used to identify platelets and infer their activation state. We observe clear differences among the four types of interfaces by ToF-SIMS/PCA. Some of these could be straightforwardly related to the differences in the sample morphology and known effects of platelet activation, but others are more subtle. Strikingly, it was possible to differentiate between these samples by ToF-SIMS/PCA of the protein species alone. This clearly indicates that the composition, orientation, and/or conformation of the proteins in these specimens depend both on the platelets' presence and on their activation. The ToF-SIMS imaging functionality furthermore provides unique insight into the distribution of phospholipid species in these samples.