RESUMEN
Electrochemical double layers (EDLs) govern the operation of batteries, fuel cells, electrochemical sensors, and electrolyzers. However, their invisible nature makes their properties and function difficult to conceptualize, creating an impediment to the broader understanding of double-layer function required for future technologies in energy storage and chemical synthesis. To render the behavior of electrochemical interfaces more intuitive, we made the rearrangement of interfacial components audible by employing the EDL as a variable element in a relaxation oscillator circuit. Connecting the circuit to a speaker generated an audible output corresponding to the change in potential resulting from EDL rearrangement. Variations in the applied voltage, electrolyte concentration and identity, as well as in the electrode material, yielded audible frequency variations that provide an intuitive understanding of EDL behavior. We expect that hearing the trends in behavior will provide a helpful and alternative method for understanding molecular movement at the electrochemical interface.
RESUMEN
PURPOSE: We sought to evaluate the benefits of patient-controlled sedation with propofol for minor oral surgery. PATIENTS AND METHODS: After instructions were given on how to use the technique, 28 male and 24 female patients sedated themselves during minor oral surgery with titrating 18-mg bolus doses of propofol with a lockout period of 1 minute. RESULTS: Surgery lasted from 5 to 29 minutes; 28 patients were moderately and 17 were deeply sedated. Seven patients were oversedated. All of those who were oversedated responded to commands within 1 minute of being unresponsive and continued to obtain increments of propofol. Vital signs were stable in all patients even during oversedation. Eighteen patients were talkative, and 17 complained of pain along the vein. Operating conditions were good in 38, fair in 12, and poor in 2. The majority, 48 patients, were relaxed, and 47 were willing to undergo the sedation technique again. Ten had total, 22 had partial, and 20 had no amnesia. CONCLUSIONS: Relaxed patients, good operating conditions, and quick recovery of oversedated patients without unstable vital signs provide evidence that propofol has favorable pharmacokinetic and pharmacodynamic properties for patient-controlled sedation. This study also highlights the importance of close monitoring of patients during patient-controlled sedation.