Metabolite Imaging at the Margin: Visualizing Metabolic Tumor Gradients Using Mass Spectrometry.

Glioblastoma multiforme (GBM) tumors are highly metabolic and vascularized, yet little has been reported regarding the spatial localization of metabolic activity within these tumors. A mass spectrometry imaging (MSI) study by Randall and colleagues in this issue provides provocative observations of metabolic gradients in xenograft GBM models. The intensity of acylcarnitines is dramatically increased at tumor margins, which interface with normal tissue, but not in tumor margins at the edge of the brain. A secondary examination of drug metabolites suggests that the observed metabolic gradients are pharmacologically relevant. These findings underscore previously undescribed spatial metabolic heterogeneity in GBM biology and opportunities for MSI investigations.See related article by Randall et al., p. 1258.

Fabrication and Compressive Properties of Low to Medium Porosity Closed-Cell Porous Aluminum Using PMMA Space Holder Technique.

In recent years, closed-cell porous Aluminum (Al) has drawn increasing attention, particularly in the applications requiring reduced weight and energy absorption capability such as in the automotive and aerospace industries. In the present work, porous Al with closed-cell structure was successfully fabricated by powder metallurgy technique using PMMA as a space holder. The effects of the amount of PMMA powder on the porosity, density, microstructure and compressive behaviors of the porous specimens were systematically evaluated. The results showed that closed-cell porous Al having different porosities (12%-32%) and densities (1.6478 g/cm³, 1.5125 g/cm³ and 1.305 g/cm³) could be produced by varying the amount of PMMA (20-30 wt %). Meanwhile, the compressive behavior results demonstrated that the plateau stress decreased and the energy absorption capacity increased with increasing amount of PMMA. However, the maximum energy absorption capacity was achieved in the closed-cell porous Al with the addition of 25 wt % PMMA. Therefore, fabrication of closed-cell porous Al using 25 wt % PMMA is considered as the optimal condition in the present study since the resultant closed-cell porous Al possessed good combinations of porosity, density and plateau stress, as well as energy absorption capacity.