tailieunhanh - New Developments in Biomedical Engineering_1

Biomedical Engineering is a highly interdisciplinary and well established discipline spanning across engineering, medicine and biology. A single definition of Biomedical Engineering is hardly unanimously accepted but it is often easier to identify what activities are included in it. This volume collects works on recent advances in Biomedical Engineering and provides a bird-view on a very broad field, ranging from purely theoretical frameworks to clinical applications and from diagnosis to treatment | 1 Nonparametric Modeling and Model-Based Control of the Insulin-Glucose System Mihalis G. Markakis 1 Georgios D. Mitsis 2 George P. Papavassilopoulos 3 and Vasilis Z. Marmarelis 4 1 Massachusetts Institute of Technology Cambridge MA USA 2 University of Cyprus Nicosia Cyprus 3 National Technical University of Athens Athens Greece 4 University of Southern California Los Angeles CA USA 1. Introduction Diabetes represents a major threat to public health with alarmingly rising trends of incidence and severity in recent years as it appears to correlate closely with emerging patterns of nutrition diet and behavior exercise worldwide. The concentration of blood glucose in healthy human subjects is about 90 mg dl and defines the state of normoglycaemia. Significant and prolonged deviations from this level may give rise to numerous pathologies with serious and extensive clinical impact that is increasingly recognized by current medical practice. When blood glucose concentration falls under 60 mg dl we have the acute and very dangerous state of hypoglycaemia that may lead to brain damage or even death if prolonged. On the other hand when blood glucose concentration rises above 120 mg dl for prolonged periods of time we are faced with the detrimental state of hyperglycaemia that may cause a host of long-term health problems . neuropathies kidney failure loss of vision etc. . The severity of the latter clinical effects is increasingly recognized as medical science advances and diabetes is revealed as a major lurking threat to public health with long-term repercussions. Prolonged hyperglycaemia is usually caused by defects in insulin production insulin action sensitivity or both Carson et al. 1983 . Although blood glucose concentration depends also on the action of several other hormones . epinephrine norepinephrine glucagon cortisol the exact quantitative nature of this dependence remains poorly understood and the effects of insulin are considered the most important. So .