Hierarchical self-assembly of metal-organic supramolecular fibers with lanthanide-derived functionalities.

Achieving organized assembly structures with high complexity and adjustable functionalities is a central quest in supramolecular chemistry. In this report, we study what happens when a discotic benzene-1,3,5-tricarboxamide (BTA) ligand containing three dipicolinic acid (DPA) groups is allowed to coordinate with lanthanide (Ln) ions. A multi-BTA coordination cluster forms, which behaves as a type of "supramolecular monomer", stacking into fibers via hydrogen bonds enabled by multiple BTA cores. The fibrous morphology and size, as well as the packing unit and the process by which it grows, were investigated by light scattering measurements, luminescence spectra, TEM images and molecular simulation data. More notably, by selecting the kind of lanthanide or mixture of lanthanides that is incorporated, tunable luminescence and magnetic relaxation properties without compromising the fibrous structure can be realized. This case of hierarchical self-assembly is made possible by the special structure of our BTA-like building block, which makes non-covalent bond types that are different along the radial (coordination bonds) and axial (H-bonds) directions, respectively, each with just the right strength. Moreover, the use of lanthanide coordination leads to materials with metal-derived optical and magnetic properties. Therefore, the established approach demonstrates a novel strategy for designing and fabrication of multi-functional supramolecular materials.

Heterotopic Pancreas in Middle Ear: A Case Report.

Heterotopic pancreas is the congenital presence of pancreatic tissue outside its normal location in the absence of vascular and anatomical connection with the main pancreas. To our knowledge, no case of heterotopic pancreas cyst in the middle ear has been reported to date. In this study, we report the first case of a 6-year-old boy with ectopic pancreas in the area of middle ear. The patient underwent canal wall down mastoidectomy with tympanoplasty. It was finally diagnosed as ectopic pancreas (left middle ear). During the 6-year follow-up, no evidence of recurrence or residual disease in the middle ear cleft or mastoid was found. Heterotopic pancreas in the middle ear is an uncommon condition and may present with otorrhea or aural fullness. Diagnosis is usually straightforward on the histologic evaluation of resection specimen, complemented with immun ohist ochem istry . Total excision with such lesion is preferred to avoid some complications. Regular follow-up is necessary due to the potential risk of recurrence and malignant transformation.