[Preclinical tests of additive materials for personified endoprostheses of hand joints]. / Doklinicheskie ispytaniia additivnykh materialov dlia izgotovleniia personifitsirovannykh éndoprotezov sustavov kisti v éksperimente.

AIM: To evaluate the biocompatibility of additive materials for personified endoprostheses of hand joints in vivo. MATERIAL AND METHODS: We tested a material based on titanium that was implanted into muscles and bone tissue in experiment on rabbits. Follow-up was 30 and 90 days. RESULTS: Implantation into muscle tissue is accompanied by reaction against foreign body followed by fibrosis without concomitant inflammation. Induction of osteogenesis and trabecular structures remodeling were detected after implantation into bone tissue. CONCLUSION: Biocompatibility of tested titanium-based material was confirmed.

The influence of laser-induced nanosecond rise-time stress waves on the microstructure and surface chemical activity of single crystal Cu nanopillars.

An apparatus and test procedure for fabrication and loading of single crystal metal nanopillars under extremely high pressures (>1 GPa) and strain rates (>107 s-1), using laser-generated stress waves, are presented. Single-crystalline Cu pillars (∼1.20 µm in tall and ∼0.45 µm in diameter) prepared via focused ion beam milling of Cu(001) substrates are shock-loaded using this approach with the dilatational stress waves propagating along the [001] axis of the pillars. Transmission electron microscopy observations of shock-loaded pillars show that dislocation density decreases and that their orientation changes with increasing stress wave amplitude, indicative of dislocation motion. The shock-loaded pillars exhibit enhanced chemical reactivity when submerged in oil and isopropyl alcohol solutions, due likely to the exposure of clean surfaces via surface spallation and formation of surface steps and nanoscale facets through dislocation motion to the surface of the pillars, resulting in growth of thin oxide films on the surfaces of the pillars.

In situ electron backscattered diffraction of individual GaAs nanowires.

We suggest and demonstrate that electron backscattered diffraction, a scanning electron microscope-based technique, can be used for non-destructive structural and morphological characterization of statistically significant number of nanowires in situ on their growth substrate. We obtain morphological, crystal phase, and crystal orientation information of individual GaAs nanowires in situ on the growth substrate GaAs(111) B. Our results, verified using transmission electron microscopy and selected area electron diffraction analyses of the same set of wires, indicate that most wires possess a wurtzite structure with a high density of thin structural defects aligned normal to the wire growth axis, while others grow defect-free with a zincblende structure. The demonstrated approach is general, applicable to other material systems, and is expected to provide important insights into the role of substrate structure on nanowire structure on nanowire crystallinity and growth orientation.

AFM capabilities in characterization of particles and surfaces: from angstroms to microns.

Scanning probe microscopy (SPM), invented 25 years ago, is now routinely employed as a surface characterization technique. Atomic force microscopy (AFM) is the most widely used form of SPM, since AFM can be used in ambient conditions with minimal sample preparation. Examples of applications relevant to cosmetics include, but are not limited to, hair and skin roughness measurements and powder particle and nano-emulsion characterization. AFM is well suited for individual particle characterization, especially for measurements of volume, height, size, shape, aspect ratio, and particle surface morphology. Statistical distributions for a large set of particles can be generated through single-particle analysis techniques (i.e., ensemble-like information). AFM is better capable of resolving complex particle-size distributions than dynamic light-scattering (DLS). Single-particle analysis techniques with AFM can be more cost- and time-effective than analyses using scanning electron microscopy (SEM). However, AFM offers resolution that is comparable to or greater than SEM or transmission electron microscopy (TEM) and routinely allows direct measurements of the particle height and volume and produces images easily displayed in a quantified 3D format.