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The application of our cycloSaligenyl- (cycloSal) pronucleotide concept to the approved anti-HIV dideoxynucleoside 3′-azido-3′-deoxythymidine AZT (1) is reported. This pro-nucleotide concept has been designed to deliver the corresponding 3′-azido-3′-deoxythymidine monophosphate AZTMP (2) by selective chemical hydrolysis from the lipophilic precursors cycloSal-AZTMP 4a−h. All derivatives 4a−h were synthesized using differently substituted salicyl alcohols 7a−h as starting materials. In hydrolysis studies, compounds 4 decomposed selectively releasing AZTMP (2) and the salicyl alcohols 7 following the designed tandem reaction. Furthermore, due to the electronic properties introduced by substituents, the half-lives of the triesters 4 could be ajusted over a wide range. Phosphotriesters 4 exhibited considerable biological activity in HIV-1 and HIV-2 infected wild-type human T-lymphocyte (CEM/O) cells, whereas, contrary to our expectations, nearly all activity was lost in HIV-2 infected thymidine-kinase-deficient CEM cells.
Octahedron-shaped porous scaffolds made from shape memory nickel–titanium (NiTi) were manufactured with different solid volume fractions using selective laser melting (SLM). Various SLM parameters were selected to affect the mechanical behaviour and shape memory response. It was shown that high laser power with high scanning speed (HP) parameters reduced the martensitic transformation temperatures as compared to low laser power low scanning speed (LP) parameters, resulting in an increased pseudoelastic behaviour (due to presence of austenite at room temperature). HP parameters, however, led to a larger geometrical mismatch with the original design and a higher solid volume fraction. The compression behaviours were also analysed and exhibited in correlation with the volume fractions.
