New magnesium‐tin‐calcium alloys offer the potential to improve the property profile and to extend the range of applications for magnesium alloys. Alloy development is undertaken in accordance to the formation of intermetallic phases during casting or during subsequent heat treatment. These intermetallic phases may contribute to room temperature strength as well as to the improvement of creep properties. Therefore the behaviour and the structure of these phases needs to be understood in more detail when using these materials in the as‐cast condition or after subsequent heat treatment.
Our report describes for the first time the continuous long-term intrathecal application of S(+)-ketamine in a patient with chronic pain and morphine tolerance. Intrathecally applied S(+)-ketamine led to a significant pain reduction and consecutively reduced the doses of intrathecal morphine required for pain relief even several weeks after the cessation of the 24-day period of intrathecal S(+)-ketamine administration.
The microstructural changes and corrosion response of Resoloy Ò , a resorbable Mg-Dy-based alloy, are the focus of this study. Hardness, tensile and compressive, and bending tests are used to monitor the changes in the mechanical properties of this material. The corrosion behavior is investigated by stress corrosion of C-rings. Hot-extruded tubes are solution heat-treated at different temperatures and times. The as-extruded condition shows a homogeneous fine-grained microstructure with matrix long-period stacking-ordered (LPSO) structures. Heat treatment at low temperatures and for short times does not significantly change the microstructure but reduces the hardness. Solution heat treatment at relatively high annealing temperatures and long annealing times causes grain growth, resulting in reduced hardness. The microstructure becomes inhomogeneous, medium-sized grains grow, the matrix LPSO structures dissolve, and small bulk LPSO phases develop. The matrix LPSO structures have a positive effect on the corrosion behavior. In particular, the short-term annealing condition shows the most uniform corrosion morphology. Resoloy Ò is not free of pitting corrosion, but none of the samples fails by cracking.
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