Tissue oxygenation and vascular reactivity as measured with Near-Infrared Spectroscopy in (perioperative) patients

Many processes surrounding surgery can influence the oxygen supply or consumption of organs. This thesis aimed to gain insight into a measurement method that can non-invasively measure oxygen levels in tissue: near-infrared spectroscopy (NIRS). Early detection of oxygen deficiency in the kidney or brain of patients during surgery might prevent damage to these organs.In literature, lower kidney NIRS values were associated with kidney damage after surgery in approximately 63% of the cases. Unfortunately, we cannot recommend kidney NIRS measurements for evaluating the oxygen content in the kidney, as we discovered in healthy volunteers that kidney NIRS measurements underestimate the directly measured oxygen content in the kidney's blood vessels. We found that lower brain NIRS values (72 hours after cooling) in children born with oxygen deprivation are associated with adverse neurological development later in life. Low brain NIRS values directly after intubation in pediatric cardiac surgery are associated with increased mortality 30 days after surgery.The dynamics of small blood vessels influence the oxygen supply to the organs and can be objectified by adding a short blood vessel occlusion test to the NIRS measurements. Literature has described that the dynamics of small blood vessels decrease during surgery, possibly due to the (sterile) inflammatory reaction. Different oxygen or carbon dioxide concentrations in the inhaled air in healthy volunteers did not influence these dynamics

Diverse styles of Islamic reform among the Songhay of eastern Mali

The general aim of the dissertation is to contribute to an understanding of Islamic reform in West Africa. To this end fieldwork was conducted among the Songhay of eastern Mali, a people who experienced a sudden rise in the popularity of Islamic reform in the early 1970's which divided many communities along religious lines. The term 'Wahhabiyya', often used to describe a trend in religious reform in West Africa which is inspired largely by the Saudi Arabian model of puritan Islam, is accepted by most members of this Songhay movement. In the region of Gao, in which this locally-based Wahhabi movement emerged, the situation is one in which Islamic reform among the village population is more 'radical' and uncompromising than among town dwellers. The central concerns of the dissertation are to compare the social backgrounds and religious orientations of 'moderates' and 'radicals' and, in particular, to account for the strong appeal of Islamic reform among the villagers. In order to assess the impact of religious reform attention is paid throughout the dissertation to the social and religious life of the non-reformist population. In tracing the background of the topic it was necessary to explore the history of the Songhay with specific reference to the introduction of Islam and its place in the 'traditional' religious complex as well as changes in the family, the economy and the politicaltostructure which have occurred since the advent of French colonization. These issues are set within a general comparison of the reformist and traditionalist communities which includes consideration of the way Islam is observed, the place of leadership and organization, and the way Islamic education is implemented

A Human Operator Model for Medical Device Interaction Using Behavior-Based Hybrid Automata

This paper describes the design and implementation of a control-theoretic model that can be used to model both the discrete and continuous behavior of a human operator. The human operator model can be used to compare different device user interfaces in terms of human performance. The implemented human operator model combines an ON–OFF control model and a behavior-based hybrid automaton with three controllers. The controllers, defined as continuous, discrete, and fine-tuning behavior, simulate the user’s conceptual model of the user interface. The device model used is that of a commercial syringe pump with chevron keys, described as a formal specification. Results of the human operator model simulation were generated for 20 different numbers obtained from syringe pump log files. The simulation results werecompared over 33 trials to a lab study employing a device based on the formal specification. The result of the simulation shows a significant similarity to the result of the lab study for all the numbers used