摘要:

The development of a system for continuous glucose measurement is described. A microdialysis fibre is used to continuously withdraw the glucose sample. After passing through the microdialysis fibre the perfusion liquid enters a micro-enzyme reactor which is filled with immobilized glucose oxidase. The enzyme activity, which varies with the glucose concentration, is monitored by an oxygen electrode. The measuring system can be adapted to a desired dynamic range by varying the perfusion rale. The measurement system has been calibrated for two different perfusion rates and shows a linear response to glucose concentrations between 0–3.5 mmol at 12μL/min and 0–8 mmol at 25μl/min. A probe, which can be configured with different lengths of the dialysing fibre, has also been designed to enable subcutaneous insertion of the microdialysis fibre in clinical studies. Subcutaneous glucose sampling by means of microdialysis is suggested to be used in the design of a glucose monitoring device for clinical use.

ISSN:0309-1902    

DOI:10.3109/03091909209021982

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

In this paper we present the modelling, design, and initial experimental testing of a nerve cuff multielectrode system for selective stimulation of fibres in superficial peripheral nerve trunk regions which is capable of making a selective activation of multiple muscles. The developed multielectrode nerve cuff consists of 14 platinum stimulating electrodes embedded within a self-curling sheet of biocompatible insulation, exhibiting a spiral transverse cross-section. The spiral shape of the system is such that the number of stimulating electrodes which can be utilized depends on the diameter of the stimulated nerve. Nerves with a greater diameter automatically make use of more electrodes than thin ones. The development was based on results obtained by a histological examination of the peripheral nerves which were planned to be stimulated, and on models of excitation of myelinated nerve fibres. The modelling objectives were to determine the electric field that would be generated within a nerve trunk by a specific electrode. Moreover, the extent of initial excitation of the nerve fibres within the superficial region of the dog sciatic nerve elicited by a certain discrete stimulating electrode was predicted. For this purpose a calculation of activating function for six positions where the nerve fibres were supposed to lie within the longitudinally dissected sciatic nerve was performed. In two acute experiments on the sciatic nerve of the dog the objective was to characterize the effectiveness of the multielectrode system in monopolar selective stimulation of the superficial regions, innervating the gastrocnemius and tibialis anterior muscle. A selectivity preliminary tested by measuring the myoelectric activity of the gastrocnemius and tibialis anterior muscle after 2 months showed good results in both animals.

ISSN:0309-1902    

DOI:10.3109/03091909209021983

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Using developments from the science of electropalatography, an intra-oral access device is being developed which increases the range and sensitivity of control available to the severely physically disabled individual. The system provides the user with a consistent positional relationship between the tongue and sensor in contrast to extra-oral mounted tongue switches. The system allows the tongue to function within the oral cavity where it has maximum speed, agility and mobility and gives the user a chance to increase accuracy through practice. A major benefit of this system is its versatility. By covering the surface area of the plate with a large number of sensors, the groups of sensors that are programmed to act as switches can take any size, shape, position and number to match the user's needs and abilities. As with any developing system, a number of problems have been encountered in practical use.

ISSN:0309-1902    

DOI:10.3109/03091909209021984

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Skin-electrode impedance was determined between two disposable electrodes 5 cm apart on the volar skin of the forearm in 20 patients during cooling on cardiopulmonary bypass. Measurements were made using a constant direct current pulse of 200μs duration, at a current density of 25.6 mA cm-2. The mean inter-electrode resistance was 1.11 kΩ, and the mean inter-electrode capacitance was 33.3 nF. In 19 patients there was no change in the inter-electrode resistance or the inter-electrode capacitance with changes in skin temperature from 27.5 to 36.0°C. In one patient the inter-electrode resistance increased from 1.71 kΩat 35°C to 1.94 kΩat 31.0°C, while the inter-electrode capacitance increased from 19.6 to 26.6 nF. We conclude that temperature effects on the impedance of the stimulus electrodes are not responsible for the observed failure of evoked electromyography during clinical monitoring of neuromuscular function.

ISSN:0309-1902    

DOI:10.3109/03091909209021985

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909209021986

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909209021987

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909209021988

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

Biosensors and Chemical Sensors: Optimizing Performance Through Polymeric MaterialsEdited by P. G. Edelman and J. Wang. American Chemical Society. 1992. p. 340; ISBN 0-8412-2218-5 Price $79.95.Operating Room and Intensive Care Alarms and Information Transfer Edited by J. Hedley-Whyte. American Society for Testing and Materials. 1992. p. 51; ISBN 0-8031-1449-4, Price $19.The Heart and Cardiovascular System: Scientific Foundations, 2nd edn.Edited by H. A. Fozzard, E. Haber, R. B. Jennings and A. M. Katz. Raven Press, New York. 1991 Two-volume set, 2383 pages. ISBN 0-88167-747-7. Price $425.Mathematical and Computer Modelling of Physiological SystemsBy V. C. Rideout. Prentice Hall, Englewood Cliffs, NJ. 1991. ISBN 0-13-563354-0.

ISSN:0309-1902    

DOI:10.3109/03091909209021989

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909209021990

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909209021991

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor