Forequarter amputation combined with chest wall resection may present a difficult closure problem. In a recent case, the defect was satisfactorily closed with a free flap from the amputated extremity, employing the entire soft tissue of the forearm.

The polyacrylamide hydrogel (PAAG) Aquamid® (Contura International A/S Soeborg, Denmark) is one of the new macromolecules that are used as implants and tissue fillers in reconstruction and aesthetic surgery. This study showed, by means of radioactive isotope methods, that PAAG can exchange both physiological and non-physiological constituents very efficiently with the surrounding medium. The efflux (J, mole/(cm(2)× s), 25 °C, pH 7.2) of water (4.4 × 10(-5) ), chloride (2.4 × 10(-7) ), urea (1.0 × 10(-9) ), and glucose (1.1 × 10(-9) ) was 3-40x greater than in human red blood cells. PAAG was also accessible to sucrose, inulin, and benzylpenicillin that could not permeate biological cell membranes. The conclusion of the study is that the hydrogel structure created no significant barrier to the exchange of solvent and solutes with the surrounding medium.

Summary:Water exchange between five polyacrylamide gels (Bulkamid®, Aquamid®, Rectamid®, HV‐PAAG, Acuvue) with a physiological salt solution was determined by means of tritium‐labeled water. Urea and chloride exchange was also determined in Acuvue. The method was a modified version to measure rapid transport processes in red blood cells. The study shows that water and solutes easily exchange between the hydrogel under study and the surrounding medium, independent of the solid polymer content (2.5–40 wt%) and an over ten‐fold variation of the cross‐linking density.

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Aluminum nitride ceramics are very suitable as substrate material for thick film- / hybrid applications in the field of power electronics and microwave technology. Main features are high thermal conductivity, a thermal expansion coefficient close to silicon, good mechanical stability and dielectric properties. Thick film resistor pastes are usually composed of lead- and bismuth oxide free glass frit and ruthenium dioxide as electrical conductive component. In contrast to oxide ceramics like alumina ceramics, thermo dynamical calculations predict the reaction of ruthenium dioxide with AlN. Thus, resistor pastes for AlN are designed to build defined porosity in the films. In dependence of composition of the paste, substrate roughness and -quality varying interactions of the components and deviating film structures can be observed. On basis of different paste compositions resistors were built with varying film thicknesses. Electrical properties like resistance and its temperature coefficient as well as the power dissipation and short term overload voltage were correlated with geometrical data, chemical composition and substrate properties. Furthermore FESEM was used to characterise film properties like porosity and the interface resistor – ceramics. Users of thick film pastes are shown aspects under which conditions high quality resistors are maintained under maximum materials savings.