RESUMEN
Here, we report the development of a molecular rotary switch (a "stator-rotor" consisting of a single oxygen molecule as a stator and a single pyridine molecule as a rotor) on a silver surface. The pyridine molecule was bonded to the oxygen molecule and was found to rotate to enable "ON" or "OFF" vibrational conductance through the oxygen molecule. Four stable sites around the oxygen molecule were observed, and vibration conductance turned on and off depending on the site at which the pyridine molecule bonded. The spatially resolved mapping of the vibrational change revealed two locations of maximal vibration intensity, separated by â¼3 Å. These positions acted as two conducting channels. The two distinct vibrational energy levels were associated with the switching process. Adsorption-induced electron transfer between the silver layers and the molecules enhanced the local interactions between the molecules. The two vibration modes were excited by resonant tunneling despite substantial interactions between the molecules, which resulted in a decrease in tunneling conductance. An independent pathway exists for the vibrational excitation process by tunneling electrons and intermolecular interactions.
RESUMEN
A 55-year-old female was diagnosed with L5-S1 degenerative disc disease (DDD). Initial scores by the visual analogue scale (VAS) were 5 (back) and 9 (leg) and the Oswestry disability index (ODI) was 32. Arthroplasty was performed. Clinical and radiographic monitoring took place thereafter at one month, three months, six months and annually. At one month, VAS scores were 2 (back) and 3 (leg), ODI was 12 and ROM was 2.1° by radiographs. At two years, VAS scores were 1 (back) and 2 (leg), ODI was 6 and ROM was approaching 0. Five years after surgery, the entire operated segment (L5-S1) was solidly fused. A malpositioned disc implant may impair normal spinal movement, culminating in heterotopic ossification or complete fusion of the operated segment.