ISSN:0309-1902    

DOI:10.3109/03091909609032523

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

In this paper, the ECG response of the human body subjected to vibrations is investigated. Measurements relied on recording the ECG and then computing the normalized difference of the ECG power spectrum density. Ten subjects aged 20–22 years old were exposed for 15 min to vertical vibrations in the frequency range 5–30 Hz. Results show either depression or elevation of the ST segment indicating heart muscle fatigue. The power spectrum density normalized difference also shows that the maximum difference takes place at 8 Hz vibrations frequency which is thought to be around the resonance frequency of the heart.

ISSN:0309-1902    

DOI:10.3109/03091909609032524

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

With the assistance of crutches and functional electrical stimulation (FES) we are able to restore standing and simple gait in some spinal cord injured (SCI) patients. In the present rehabilitative systems the patient divides the gait cycle into‘stance’and‘swing’phase by using pushbuttons mounted in the handles of the crutches. These are then hard wired to the functional electrical stimulator. We present the development and evaluation of a surface mount technology based telemetry system that provides reliable and interference resistant wireless control of FES assisted walking. The system makes use of radio frequency carriers operating at a frequency of 40 MHz. Crutch pushbutton signals are coded and transferred from the transmitter placed in the crutch to the receiver which is firmly attached to the patient's waist and connected to the stimulator. The telemetry system was found to be of special importance for both complete and incomplete SCI subjects and is currently in use at the Rehabilitation Institute of the Republic of Slovenia.

ISSN:0309-1902    

DOI:10.3109/03091909609032525

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

X-ray equipment characteristics and performance have an important influence on radiation doses to patients. In order that these factors can be taken into consideration when X-ray equipment is purchased, dose related requirements need to be included in specifications and additional dose information requested from manufacturers. Dose factors include techniques that directly reduce exposure; use of low attenuation materials; provision of flexibility in choice of exposure parameters; and availability of data for dose assessment. If a standard format can be developed, this should enable manufacturers to supply this information. Specifications for different types of X-ray equipment and lists of dose information to be requested from manufacturers have been prepared by the Scottish Radiation Protection Advisers’Group for use in hospitals throughout Scotland. It is hoped that this will allow patient dose to be taken into account when X-ray equipment is purchased.

ISSN:0309-1902    

DOI:10.3109/03091909609032526

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

A general field theory has been developed for the EM wave propagation on a tape helix with embedded bone, muscle, fat and skin co-axial biological layers in a multilayered dielectric environment. The electric and magnetic fields in every biological/dielectric layer is formulated in terms of complex modified Bessel functions and complex exponentials, i.e. in terms of complex radial and axial propagation constants for the azimuthally symmetric and higher order spatial harmonics. A complete dispersion relation is derived by substituting the field expressions into as many boundary conditions as there are unknown constants. The dispersion relation is numerically solved for the complex axial propagation constant and hence for the phase velocity and depth of penetration for n = 0 and 1 modes propagating along three dielectric loaded tape helices of different dimensions at several spot frequencies within the range of 300 MHz to 3·00 GHz. The results for variations in normalized phase velocity and depth of penetration with frequency for these modes separately and for the combined mode are presented. The patterns of specific absorption rate (SAR) across the cross-section of the dielectric loaded helices are also computed and presented. The variations with frequency, and cross-sectional dimension of the helix of the normalized phase velocity, axial depth and SAR across the cross-section of each of the helices are discussed for the modes considered. The theoretical results for the propagation constant obtained by using a tape helix model for the azimuthally symmetric mode propagating along a wire helix loaded with a phantom muscle sample of known dielectric constant are compared with experimental results and with those obtained theoretically employing a sheath helix model at 2·45 and 2·55 GHz. The use of a helix for human limb hyperthermia is also discussed.

ISSN:0309-1902    

DOI:10.3109/03091909609032527

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909609032528

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909609032529

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909609032530

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091909609032531

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor