One-step control of hierarchy and functionality of polymeric surfaces in a new plasma nanotechnology reactor.

Hierarchical micro-nanostructured surfaces are key components of 'smart' multifunctional materials, used to control wetting, adhesion, tactile, friction, optical, antifogging, antibacterial, and many more surface properties. Hierarchical surfaces comprise random or ordered structures ranked by their length scale spanning the range from a few nanometers to a few micrometers, with the larger microstructures typically embedding smaller nanostructures. Despite the importance of hierarchical surfaces, there have been few studies on their precise and controlled fabrication or their quantitative characterization, and they usually involve multiple and complex fabrication steps. Here, we present a new plasma nanotechnology, which we term 'nanoinhibit', and a new plasma reactor for producing in one facile process-step-controlled hierarchy at will on polymeric surfaces. We couple the new plasma nanotechnology with detailed computational nanometrology based on the analysis of scanning electron microscopy images and targeted to specific functionality. We showcase the potential of 'nanoinhibit' for functional surface fabrication by controlling the wetting and optical functionality of the fabricated hierarchical surfaces and showing its dependence on surface morphology metrics. Finally, we observe that 'nanoinhibit' produces a new class of 'strong hierarchical' surfaces exhibiting spatially separated periodic and fractal-like components.

Ultra-high aspect ratio Si nanowires fabricated with plasma etching: plasma processing, mechanical stability analysis against adhesion and capillary forces and oleophobicity.

Room-temperature deep Si etching using time-multiplexed deep reactive ion etching (DRIE) processes is investigated to fabricate ultra-high aspect ratio Si nanowires (SiNWs) perpendicular to the silicon substrate. Nanopatterning is achieved using either top-down techniques (e.g. electron beam lithography) or colloidal polystyrene (PS) sphere self-assembly. The latter is a faster and more economical method if imperfections in diameter and position can be tolerated. We demonstrate wire radii from below 100 nm to several micrometers, and aspect ratios (ARs) above 100:1 with etching rates above 1 µm min(-1) using classical mass flow controllers with pulsing rise times of seconds. The mechanical stability of these nanowires is studied theoretically and experimentally against adhesion and capillary forces. It is shown that above ARs of the order of 50:1 for spacing 1 µm, SiNWs tend to bend due to adhesion forces between them. Such large adhesion forces are due to the high surface energy of silicon. Wetting the SiNWs with water and drying also gives rise to capillary forces. We find that capillary forces may be less important for SiNW collapse/bending compared to adhesion forces of dry SiNWs, contrary to what is observed for polymeric nanowires/nanopillars which have a much lower surface energy compared to silicon. Finally we show that SiNW arrays have oleophobic and superoleophobic properties, i.e. they exhibit excellent anti-wetting properties for a wide range of liquids and oils due to the re-entrant profile produced by the DRIE process and the well-designed spacing.

The Policy of our Clinic in Early Escharectomy in Burns of the Hand.

Early escharectomy in deep partial- and full-thickness burns of the hand has proved to have an advantage over late surgical treatment. It provides an improved functional and cosmetic result. Hand deformities, the need for secondary reconstructive procedures, and morbidity are significantly reduced. In our clinic we prefer to use early escharectomy in all full-thickness burns of the hand unless the patient's condition prevents it or unless the extent of the burns in the rest of the body would prevent improvement in the general outcome.

Pericardial cells for graft seeding: isolation, culture and identification.

The purpose of this study was to determine the feasibility of using the pericardium as a source of endothelial cells. Nineteen pieces of fresh pericardium were obtained from nine mongrel dogs. Cells were prepared by collagenase digestion of the pericardium for 24 minutes followed by centrifugation. The cells were divided into three groups: The supernatant subjected to no further steps, Group I (N = 6); filtration through a 15 micron porous mesh, Group II (N = 6); and Percoll gradient separation with medium 199, Group III (N = 7). The cells obtained were cultured for seven days in tissue culture media. Yield (cells x 10(5)/gram fresh tissue) was determined with Methods I, II, and III, producing 32.4 +/- 25.9 (SD), 0.96 +/- 0.6 and 0.57 +/- 0.5, respectively (I vs II or III, p less than 0.01). Fibroblast contamination determined by phase contrast light microscopy was demonstrated in 6/6 cultures with Method I, 3/6 with II and 1/7 for III (I vs III, p less than 0.01). An assay for endothelial cells (Factor VIII) was positive in 2/6 cultures with Method I, 5/6 with II and 7/7 for III (I vs III, p less than 0.01). The pericardium is a suitable organ for procurement of endothelial cells. Though reducing yield, filtration and Percoll gradient separation allows for isolation of a relatively pure culture of endothelial cells.