Giant porphyrin disks: Control of their self-assembly at liquid-solid interfaces through metal-ligand interactions

Contains fulltext : 34730.pdf (publisher's version ) (Closed access)The synthesis and self-assembly behaviour of porphyrin dodecamers 1H(2) and Zn-1, which consist of twelve porphyrins that are covalently attached to a central aromatic core, is described. According to STM, 1D and 2D NMR studies, and molecular modelling calculations, the porphyrin dodecamers have a yo-yo-shaped structure. Their large pi surface, in combination with their disk-like shape, allows them to form self-assembled structures, which in the case of Zn-1 can be tuned by adding biden-late ligands. The self-assembly of the molecules at the liquid-solid interface of 1-phenyloctane with highly oriented pyrolytic graphite or Au(111) was imaged by using STM. The porphyrin disks in the self-assembled arrays have an edge-on orientation on the surface. The addition of bidentate axial ligands to the Zn-1 molecules in the arrays allows their intermolecular distance to be precisely controlled

The amniotic membrane in ophthalmology

The amniotic membrane is the innermost of the three layers forming the fetal membranes. It was first used in 1910 in skin transplantation. Thereafter it has been used in surgical procedures related to the genito-urinary tract, skin, brain, and head and neck, among others. the first documented ophthalmological application was in the 1940s when it was used in the treatment of ocular burns. Following initial reports, its use in ocular surgery abated until recently when it was re-discovered in the Soviet Union and South America. Its introduction to North America in the early 1990s heralded a massive surge in the ophthalmic applications of this membrane. the reintroduction of amniotic membrane in ophthalmic surgery holds great promise; however, although it has been shown to be a useful and viable alternative for some conditions, it is Currently being used far in excess of its true useful potential. in many clinical situations it offers an alternative to existing management options without any distinct advantage over the others. Further studies will undoubtedly reveal the true potential of the membrane, its mechanism(s) of action, and the effective use of this tissue in ophthalmology. (C) 2004 Elsevier Inc. All rights reserved.Univ Nottingham Hosp, Queens Med Ctr, Eye Ear Nose Throat Ctr, Div Ophthalmol & Visual Sci, Nottingham NG7 2UH, EnglandUniversidade Federal de São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilWeb of Scienc

Phosphoinositides in the Mammalian Endo-lysosomal Network

The endo-lysosomal system is an interconnected tubulo-vesicular network that acts as a sorting station to process and distribute internalised cargo. This network accepts cargoes from both the plasma membrane and the biosynthetic pathway, and directs these cargos either towards the lysosome for degradation, the peri-nuclear recycling endosome for return to the cell surface, or to the trans-Golgi network. These intracellular membranes are variously enriched in different phosphoinositides that help to shape compartmental identity. These lipids act to localise a number of phosphoinositide-binding proteins that function as sorting machineries to regulate endosomal cargo sorting. Herein we discuss regulation of these machineries by phosphoinositides and explore how phosphoinositide-switching contributes toward sorting decisions made at this platform