In situ TEM observation of buffering the anode volume change by using NiTi alloy during electrochemical lithiation/delithiation

A novel Ti3Sn/NiTi shape memory alloy anode with a sandwich structure was fabricated by arc melting. In order to characterize in situ the Ti3Sn/NiTi anode microstructure changes and phase transformations during cycling, a nanoscale lithium battery was set up inside a transmission electron microscope, which consists of Li metal as the cathode, the native Li2O layer on the surface of Li metal as the solid electrolyte, and the Ti3Sn/NiTi as the anode. Only the Ti3Sn intermetallic compound experienced the electrochemical reaction, while the NiTi alloy (inactive with Li(+)) was applied for buffering the Ti3Sn volume change during cycling. An obvious reaction front of Ti3Sn migrated from one end to the other during lithiation, which can also return after delithiation. It provides direct evidence that the NiTi alloy can effectively accommodate the anode volume change during electrochemical lithiation and delithiation.

Surgical treatment of 100 patients with W-P-W syndrome

100 patients with W-P-W syndrome who had repeated attacks of supraventricular tachycardia (200-300 beats per minute) associated with syncope and hypotension were treated surgically. Most of them were refractory to medical treatment. Electrophysiological studies were done before operation and the anomalous conduction pathways (ACPs) were confirmed and localized by epicardial mapping during the operation. Among the 100 patients, 44 were of type B, 29 type A and 27 type A + B. The right ACPs were excised and the left ACPs were injected with alcohol. Four patients died after operation. 96 patients were followed up for an average of 24 months; 38 (90.5%) of 42 type B patients, 23 (82.1%) of 28 type A patients, and 17 (65.4%) of 26 type A + B patients were cured.