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The temporal and spatial development of Parkinson's disease has been characterised as the progressive formation of {\alpha}-synuclein aggregations through susceptible neuronal pathways. This article describes a new model for this progression mechanism in which Parkinsonian damage moves over time through the nervous system by the combined effect of the reaction kinetics of pathogenesis and molecular diffusion. In the reaction-diffusion model, the change from a healthy state to the disease state advances through the nervous system as a wave front of Parkinsonian damage, marking its path by accumulations of damaged {\alpha}-synuclein and neurotoxic levels of oxidative species. Progression according to this model follows the most vulnerable routes through the nervous system as described by Braak's staging theory and predicts that damage will advance at differing speeds depending upon the level and number of risk factors, in a manner that gives new insights into the variations with which Parkinson's disease develops., Comment: In memorial to Prof. Peter Wellstead. This was his last piece of work

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The use of new technology and mathematics to study the systems of nature is one of the most significant scientific trends of the century. Driven by the need for more precise scientific understand, advances in automated measurement are providing rich new sources of biological and physiological data. This data provides information with which to create mathematical models of increasing sophistication and realism - models that can emulate the performance of biological and physiological systems with sufficient accuracy to advance our understanding of living systems and disease mechanisms. New measurement and modelling methods set the stage for control and systems theory to play their role in seeking out the mechanisms and principles that regulate life. It is of inestimable importance for the future of control as a discipline that this role is performed in the correct manner. If we handle the area wisely then living systems will present a seemly boundless range of important new problems - just as physical and engineering systems have done in previous centuries. But there is a crucial difficulty. Faced with a bewildering array of choices in an unfamiliar area, how does a researcher select a worthwhile and fruitful problem? This lecture is an attempt to help by offering a control oriented guide to the labyrinthine world of biology/physiology and the control research opportunity that it holds.

In its broadest definition, systems biology is the application of a `systems' way of thinking about and doing cell biology. By implication, this also invites us to consider a systems approach in the context of medicine and the treatment of disease. In particular, the idea that systems biology can form the basis of a personalised, predictive medicine will require that much closer attention is paid to the analytic properties of the feedback loops which will be set up by a personalised approach to healthcare. To emphasize the role that feedback theory will play in understanding personalised medicine, we use the term feedback medicine to describe the issues outlined.In these notes we consider feedback and control systems concepts applied to two important themes in medical systems biology - personalised medicine and combinatorial intervention. In particular, we formulate a feedback control interpretation for the administration of medicine, and relate them to various forms of medical treatment., Comment: 22 pages, 10 figures

An active control system is described for the automatic alignment of the mirrors in a two-beam interferometer. From an initial unaligned position the active control system determines the degree of misalignment and adjusts the relative mirror positions accordingly. An embodiment of the system is described for a Michelson interferometer in which one of the mirrors is mounted upon three piezoelectric transducers PZT arranged so that they can both tilt and retard the mirror. Laser sources and corresponding photodetectors are also incorporated such that a control system can use the PZT actuators to produce a series of mirror movements relative to the fixed mirror and give a set of two-dimensional diffraction patterns one for each of the laser photodetectors. Amplitude and phase information is extracted from these patterns which enables the control system to align the mirrors such that the diffraction pattern maxima is at the center of the instrument central photodetector. In a further stage of the control algorithm, the alignment accuracy is refined using information from the laser photodetectors during retardation of the mirror. In this manner, the initial mirror alignment, maintaining that alignment during retardation and diagnosis of possible misalignment, become part of a single active control technology for instrument alignment.