The effect of a non-symmetric waveform on nerve conduction block induced by high-frequency biphasic stimulation is investigated using a lumped circuit model of the unmyelinated axon based on Hodgkin-Huxley equations. The simulation results reveal that the block threshold monotonically increases with the stimulation frequency for the symmetric stimulation waveform. However, a nonmonotonic relati...

Transmembrane potential change (Δ V m) during shocks was recorded by a double-barrel microelectrode in 12 isolated guinea pig papillary muscles. After 10 S1 stimuli, square-wave S2 shocks of both polarities were given consisting of 10-ms monophasic and 10/10-ms and 5/5-ms biphasic waveforms that created potential gradients from 1.1 ± 0.3 to 11.9 ± 0.4 V/cm. S2 shocks were applied with 30, 60- t...

Abstract Aims Interpretation of Doppler audio signals among non-podiatrist has not been thoroughly investigated. This study analyses the accuracy interpretation clinicians. Methods A single-centre prospective single blind was used. Clinicians in vascular department and with prior experience a district general hospital participated interpreting 15 12-second (5 monophasic, 5 biphasic triphasic) i...

The cover art illustrates the phase-transfer catalysis effective for asymmetric Strecker reaction of ketoimines with potassium cyanide under solid-liquid biphasic conditions. Chiral 1,2,3-triazolium ion featuring prominent hydrogen-bond donating and anion-binding capabilities allows establishment a highly efficient enantioselective process preparation sterically congested chiral α-amino nitrile...

Background-We tested the hypothesis that the shape of the shock waveform affects not only

This study used the Frankenhaeuser-Huxley axonal model to analyze the effects of non-symmetric waveforms on conduction block of myelinated axons induced by high-frequency (10-300 kHz) biphasic electrical stimulation. The results predict a monotonic relationship between block threshold and stimulation frequency for symmetric waveform and a non-monotonic relationship for non-symmetric waveforms. ...

OBJECTIVE This is a study of the influence of transthoracic impedance (TTI) on defibrillation, resuscitation and survival in patients with out-of-hospital cardiac arrest (OHCA), treated with a non-escalating impedance-compensating 150 J biphasic waveform defibrillator. METHODS Cardiac arrest data from two EMS systems were analyzed retrospectively. All witnessed arrests from patients who prese...

OBJECTIVE To determine which mechanisms lead to activation of neurons in the motor cortex during transcranial magnetic stimulation (TMS) with different current directions and pulse waveforms. METHODS The total electric field induced in a simplified model of a cortical sulcus by a figure-eight coil was calculated using the finite element method (FEM). This electric field was then used as the i...

ABNORMAL capnographs are not unusual in clinical anesthesia. These typically result from uneven ventilation in patients with lung disease. Previous reports also have noted abnormal capnograph tracings resulting from loose connections between the end-tidal carbon dioxide sample line and the gas analyzer or other leaks in the system. The resulting biphasic waveform has been described as a long lo...

OBJECTIVES To evaluate the stimulation effectiveness of different magnetic stimulator devices with respect to pulse waveform and current direction in the motor cortex. METHODS In 8 normal subjects we determined motor thresholds of transcranial magnetic stimulation in a small hand muscle. We used focal figure-of-eight coils of 3 common stimulators (Dantec Magpro, Magstim 200 and Magstim Rapid)...