This study 1) compares the negative chronotropic and dromotropic actions of adenosine in guinea pig, rat, and rabbit hearts; 2) investigates the mechanism(s) for the different responses; and 3) determines the physiological implications. Isolated perfused hearts were instrumented for measurement of atrial rate and atrioventricular (AV) nodal conduction time. Differences in metabolism of adenosin...

We present a model for the charge transfer contribution to surface-enhanced Raman spectroscopy (SERS) in a molecular junction. The model is a generalization of the equilibrium scheme for SERS of a molecule adsorbed on a metal surface [B. N. J. Persson. Chem. Phys. Lett. 82, 561 (1981)]. We extend the same physical consideration to a nonequilibrium situation in a biased molecular junction and to...

Ossicular repositioning and ossicular prostheses are said to offer an oppotunity to preserve the air space of the middle ear and improve the transmission of sound to the stape footplate. Depending upon the pathological circumstances, any convenient remaining portion of the auditory ossicles may be used to reconstruct a functioning ossicular chain. But the problem of reconstruction is not simple...

• Delay in atrioventricular conduction has been attributed mainly to slow conduction of excitation at the prenodal tissue of the A-V node." Electrophysiological studies of this prenodal tissue have revealed several common physiological properties, such as low amplitude and overshoot of action potential, low resting potential, low rate of depolarization and low conduction velocity which are spec...

This ECG was recorded from a 93 year old patient with a previously documented third degree AV block and an underlying LBBB. The twelve lead ECG demonstrates sinus bradycardia at a rate of 52 beats per minute, a PR interval of 230 milliseconds, and a left bundle branch block (Figure 1). In figure 2, a rhythm strip of leads V1, II and V5 shows sinus rhythm with AV block. Note that only P waves in...

BACKGROUND To define the electrophysiological mechanism(s) of inducible and spontaneously occurring ventricular arrhythmias associated with nonischemic cardiomyopathy, 3-dimensional intraoperative mapping from 156 intramural sites was performed in 6 patients with idiopathic dilated cardiomyopathy undergoing cardiac transplantation. METHODS AND RESULTS Electrode density was sufficient to deter...

Resistive switching memory (ReRAM) has attracted much attention in recent times owing to its fast switching, simple structure, and non-volatility. Flexible and transparent electronic devices have also attracted considerable attention. We therefore fabricated an Al2O3-based ReRAM with transparent indium-zinc-oxide (IZO) electrodes on a flexible substrate. The device transmittance was found to be...

Sudden cardiac death forms a major cause of mortality. Myocardial ischemia-induced ventricular fibrillation (VF) is frequently the underlying mechanism. Ventricular arrhythmias arise in two distinct phases during the first hour of ischemia. The first, the 1A phase, has been extensively studied, and few studies relate to the 1B phase. The latter is associated with intercellular electrical uncoup...

Electron tunneling through self-assembled monolayers (SAMs) of alkanethiols was investigated using nanometer scale devices that allow temperature-dependent current-voltage, I(V, T), measurements. The I(V, T) measurement results show, for the first time, temperature-independent electron transport characteristics, proving direct tunneling as the transport mechanism in alkanethiol SAMs. The measur...