Clean preparation of nanoparticulate metals in porous supports: a supercritical route

Here we present the synthesis of nanometre sized silver particles which have been trapped within porous substrates; poly( styrene-divinylbenzene) beads and silica aerogels. This is the first time that supercritical carbon dioxide has been used to impregnate such porous materials with silver coordination complexes. In this paper we demonstrate that control over the resultant nanoparticles with respect to size, loading and distribution in the support material has been achieved by simple choice of the precursor complex. The solubility of the precursor complexes in the supercritical solvent is shown to be one of the key parameters in determining the size of the nanoparticles, their distribution and their homogeneity within the support matrix. Moreover, we demonstrate that the same methodology can be applied to two very different substrate materials. In the particular case of aerogels, conventional organic solvents could not be used to prepare nanoparticles because the surface tension of the solvent would lead to fracturing of the aerogel structure.

Judicial Rehabilitation and the ‘Clean Bill of Health’ in Criminal Justice.

Drawing on an important survey of European and Australian policies toward ‘judicial rehabilitation,’ this article makes the following arguments. First, the rehabilitation movement should return to the origins of the word ‘rehabilitation’ and focus at least as much on efforts to remove and relieve ex-prisoner stigma as on treatment and reform efforts. There will be no ‘rehabilitation revolution’ without this. Second, these efforts should involve active, not passive redemption. Rehabilitation processes that require almost a decade or more of ‘crime-free’ behaviour before forgiving an individual for his or her crimes are just and fair, but they miss the point of rehabilitation. Policies should encourage, support and facilitate good behaviour and not just reward it in retrospect. Third, rehabilitation should not just be done, but be ‘seen to be done,’ ideally in a ritualised format. This sends an important message to the individual and wider society. Finally, I argue that it may be better to forgive than forget past crimes. That is, rather than burying past crimes as if they never happened, states should instead acknowledge and formally recognise that people can change, that good people can do bad things, and that all individuals should be able to move on from past convictions.