Epicardial delivery of a conductive membrane synchronizes conduction to reduce atrial fibrillation.

Conductive polymers have been investigated as a medium for the transmission of electrical signals in biological tissues, but their capacity to rewire cardiac tissue has not been evaluated. Myocardial tissue is unique in being able to generate an electrical potential at a fixed rate; this potential spreads rapidly among cells to trigger muscle contractions. Tissue injuries result in myocardial fibrosis and subsequent non-uniform conductivity, leading to arrhythmia. Atrial fibrillation (AF) is the most common sustained arrhythmia, associated with disruption of atrial electrical signaling, which can potentially be restored by the epicardial delivery of conductive polymers. In this work, poly-3-amino-4-methoxybenzoic acid, conjugated to gelatin, is fabricated as a membrane (PAMB-G) to support conductive velocities that are close to that of the myocardium. A cross-linked gelatin membrane (Gelatin) is used as a control. The as-fabricated PAMB-G has similar tensile elasticities, determined using the Young's modulus, as contracting myocardium; it can also transmit electrical signals to initiate cardiac cell and tissue excitation. Delivering PAMB-G onto the atrium of a rat AF model shortens AF duration and improves post-AF recovery for the duration of a 28-day-long study. Atrial tissue in the PAMB-G-implanted group has lower impedance, higher conduction velocity, and higher field potential amplitude than that in the Gelatin-implanted group. Therefore, the as-proposed PAMB-G is a suitable medium for restoring proper cardiac electrical signaling in AF hearts.

Slowing and storage of double light pulses in a Pr3+:Y2SiO5 crystal.

We experimentally demonstrate the slowing and storage of double light pulses in a Pr(3+):Y(2)SiO(5) crystal using a multilevel-tripod scheme. Owing to double dark-state polaritons of the tripod-type system, two signal pulses can be simultaneously slowed. Also, we realize the simultaneous storage (and retrieval) of double light pulses by switching off (and back on) the control field. Slowing and storage of double light pulses in solids may have practical applications in quantum information and quantum networks.

Three-channel all-optical routing in a Pr3+:Y2SiO5 crystal.

We experimentally demonstrate a three-channel all-optical routing based on light storage in a Pr(3+):Y(2)SiO(5) crystal. By switching off the control field under the condition of electromagnetically induced transparency, the optical information of the probe light pulse can be stored in the crystal. When three retrieve control fields are switched on in the release process, the stored optical information from one light channel can be transferred (or distributed) into three different light channels. Also we show that this all-optical routing can be time-delayed. Such a multichannel all-optical routing in solids may have practical applications in quantum information and all-optical network.

Enantioselective recognition of carboxylates: a receptor derived from alpha-aminoxy acids functions as a chiral shift reagent for carboxylic acids.

Enantioselective recognition of carboxylates has important implications in asymmetric synthesis and drug discovery. We have prepared a novel C2-symmetric receptor 1 from alpha-aminoxy acids in a high overall yield. A series of chiral recognition studies indicate that receptor 1 not only can bind to carboxylate ions tightly but also has a good ability to recognize enantiomers of a broad variety of carboxylic acids in the 1H NMR spectra. Thus, the receptor 1 can be used as a chiral shift reagent for the determination of enantiomeric purities of chiral carboxylic acids by 1H NMR directly and rapidly.