Left side clot in transit in double-lung transplantation diagnosticated by transesophageal echocardiography: what's next?

A 61-year-old man with no predisposition to thrombosis underwent sequential double lung transplantation without extracorporeal membrane oxygenation (ECMO) support due to terminal stage COPD. After implantation and reperfusion of both lungs, a complete transoesophageal echocardiography study was performed to check the pulmonary venous anastomosis. The study showed a large, heterogeneous, dense, hyperechoic free-floating mass in the left atrium compatible with a clot in transit from the pulmonary circulation. The surgical team were notified of this finding so that they could reopen the anastomosis and remove the clot to prevent a major complication. There were no clinical manifestations when the patient was awakened.

Extended covalent containers: synthesis and guest encapsulation.

The synthesis and characterization of two new covalent capsules are described. The structures use biphenyl and azobenzene spacers capped on both ends with deep cavitands. The tubular capsules are robust in a range of media and accommodate guests as long as squalene.

Synthesis of a Möbius aromatic hydrocarbon.

The defining feature of aromatic hydrocarbon compounds is a cyclic molecular structure stabilized by the delocalization of pi electrons that, according to the Hückel rule, need to total 4n + 2 (n = 1,2, em leader ); cyclic compounds with 4n pi electrons are antiaromatic and unstable. But in 1964, Heilbronner predicted on purely theoretical grounds that cyclic molecules with the topology of a Möbius band--a ring constructed by joining the ends of a rectangular strip after having given one end half a twist--should be aromatic if they contain 4n, rather than 4n + 2, pi electrons. The prediction stimulated attempts to synthesize Möbius aromatic hydrocarbons, but twisted cyclic molecules are destabilized by large ring strains, with the twist also suppressing overlap of the p orbitals involved in electron delocalization and stabilization. In larger cyclic molecules, ring strain is less pronounced but the structures are very flexible and flip back to the less-strained Hückel topology. Although transition-state species, an unstable intermediate and a non-conjugated cyclic molecule, all with a Möbius topology, have been documented, a stable aromatic Möbius system has not yet been realized. Here we report that combining a 'normal' aromatic structure (with p orbitals orthogonal to the ring plane) and a 'belt-like' aromatic structure (with p orbitals within the ring plane) yields a Möbius compound stabilized by its extended pi system.