Antagonism of cortical excitation of striatal neurons by glutamic acid diethyl ester: evidence for glutamic acid as an excitatory transmitter in the rat striatum.

GDEE antagonism of iontophoretic amino acid excitations in the intact hippocampus and in the hippocampal slice preparation

A continuous wave Doppler radar, operating as a phase-locked-loop in phase demodulator configuration, is proposed and in vivo demonstrated for noncontact vital signs monitoring. The radar architecture exhibits a unique precision in tracking the phase modulation caused by human cardiopulmonary activity from which heartbeat and respiration can simultaneously be extracted. The single mixer architecture is immune to the null point and does not require small-angle approximation conditions, which distinguishes it from pre-existing other approaches. This enables the proposed radar to behave highly linear, with very precise detection of phase modulations induced by any kind of movement, independently from amplitude and speed. After simulations and technical tests to validate functionality and safety of the proposed architecture, a practical setup was demonstrated on human volunteers. Wavelet independent component analysis was applied to successfully retrieve respiratory and heart rate information from the radar baseband signal.

A Direct Phase-Tracking Doppler Radar Using Wavelet Independent Component Analysis for Non-Contact Respiratory and Heart Rate Monitoring

The determination of the effect of loading of the chest wall exerted by a contact phonocardiographic microphone, has been attempted in earlier investigations by the measurement of the mechanical properties of the microphone and the chest wall in combination with mechanical models describing the coupling phenomenon (method 1). For computing the acceleration response of the microphone applied to the chest wall a number of unverified assumptions were made. In the paper a method is described for experimental determination of the coupling characteristic. A specially designed ultralight pick-up (1 g) was applied for recording the quasi-unloaded vibrations and the average amplitude spectrum was calculated. The procedure was repeated at the same site, the chest wall successively being loaded with different masses and two commercial microphones (method 2). Logarithmic transfer functions of the loaded to unloaded situations have been computed. The experiments were performed on six healthy persons. The results of method 1 appeared to be very similar to those obtained with method 2 when a Verburg model was assumed. In this manner we determined the acceleration response of microphones applied to the chest wall, which is both of interest for standardised and quantitative phonocardiography.

The recording of heart vibrations: a problem of vibration measurement on soft tissue

Responses of hypothalamic neurones to local temperature and to acetylcholine, noradrenaline and 5-hydroxytryptamine

An absolute calibration by means of the reciprocity theorem has been applied to the calibration of contact-type phonocardiographic microphones. The methods are discussed in detail and examples of the results are presented. Human chest wall vibrations have been measured with these calibrated microphones and the results are also presented.

N. Suzumura

Papers

Absolute calibration of phonocardiographic microphones and measurements of chest wall vibration.