Real-time imaging of novel spatial and temporal responses to photodynamic stress.

Cells subjected to various forms of stress have been shown to induce bystander responses in nontargeted cells, thus extending the stress response to a larger population. However, the mechanism(s) of bystander responses remains to be clearly identified, particularly for photodynamic stress. Oxidative stress and cell viability were studied on the spatial and temporal levels after photodynamic targeting of a subpopulation of EMT6 murine mammary cancer cells in a multiwell plate by computerized time-lapse fluorescence microscopy. In the targeted population a dose-dependent loss of cell viability was observed in accordance with increased oxidative stress. This was accompanied by increased oxidative stress in bystander populations but on different time scales, reaching a maximum more rapidly in targeted cells. Treatment with extracellular catalase, or the NADPH oxidase inhibitor diphenyleneiodinium, decreased production of reactive oxygen species (ROS) in both populations. These effects are ascribed to photodynamic activation of NADPH-oxidase in the targeted cells, resulting in a rapid burst of ROS formation with hydrogen peroxide acting as the signaling molecule responsible for initiation of these photodynamic bystander responses. The consequences of increased oxidative stress in bystander cells should be considered in the overall framework of photodynamic stress.

Co-design of Distributed Systems Using Skeleton and Autonomic Management Abstractions

We discuss how common problems arising with multi/many core distributed architectures can he effectively handled through co-design of parallel/distributed programming abstractions and of autonomic management of non-functional concerns. In particular, we demonstrate how restricted patterns (or skeletons) may be efficiently managed by rule-based autonomic managers. We discuss the basic principles underlying pattern+manager co-design, current implementations inspired by this approach and some result achieved with proof-or-concept, prototype.

Real time monitoring of the polymerisation of PMMA bone cement using Raman spectroscopy

In this investigation Raman spectroscopy was shown to be a method that could be used to monitor the polymerisation of PMMA bone cement. Presently there is no objective method that orthopaedic surgeons can use to quantify the curing process of cement during surgery. Raman spectroscopy is a non-invasive, non-destructive technique that could offer such an option. Two commercially available bone cements (Palacos® R and SmartSet® HV) and different storage conditions (4 and 22°C) were used to validate the technique. Raman spectroscopy was found to be repeatable across all conditions with the completion of the polymerisation process particularly easy to establish. All tests were benchmarked against current temperature monitoring methods outlined in ISO and ASTM standards. There was found to be close agreement with the standard methods and the Raman spectroscopy used in this study.