Shrink-wrap vesicles

We describe a simple approach to the controlled removal of molecules from the membrane of large unilamellar vesicles made of fatty acids. Such vesicles shrink dramatically upon mixing with micelles composed of a mixture of fatty acid and a phospholipid (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)), as fatty acid molecules leave the vesicle membrane and accumulate within the mixed micelles. Vesicle shrinkage was confirmed by dynamic light scattering, fluorescence recovery after photobleaching of labeled vesicles, and fluorescence resonance energy transfer between lipid dyes incorporated into the vesicle membrane. Most of the encapsulated impermeable solute is retained during shrinkage, becoming concentrated by a factor of at least 50-fold in the final small vesicles. This unprecedented combination of vesicle shrinkage with retention of contents allows for the preparation of small vesicles containing high solute concentrations, and may find applications in liposomal drug delivery.     

Single-crystalline platinum nanosheets from nonionic surfactant 2-D self-assemblies at solid/aqueous solution interfaces

Single-crystalline platinum nanosheets have been prepared via a new methodology based on the chemical reduction of a platinum salt (H2PtCl6) with hydrazine at a graphite/solution interface, using polyoxyethylene (20) sorbitan monostearate (Tween 60) based self-assembly (hemicylindrical micelle) templates. The platinum nanosheets with a uniform thickness of as thin as 3.5 +/- 1 nm are surface-smooth and continuous over relatively large length scales of micrometer sizes. In striking contrast to the Tween 60 based system, no Pt nanosheets are obtained with nonaethylene glycol monododecyl ether (C12EO9) and polyoxyethylene (23) dodecyl ether (C12EO23). No Pt nanosheets are also obtainable with a laterally homogeneous layer of Tween 60 formed at the silica/solution interface. These results indicate that surfactant Tween 60 molecules with a triple polyoxyethylene structure, as well as their hemicylindrical micelle templates, play an essential role for the formation of the Pt nanosheets. It is also suggested that the interfacially directed growth of Pt metals within the aqueous shells of the Tween 60 hemicylindrical micelles induces the thin Pt crystals as thick as the aqueous shells. The present approach could be extended to prepare a wide range of novel nanostructures of noble metals, using various micelle-like self-assemblies at interfaces.     

Fabrications of potential imaging probes based on a β-alkyl substituted porphyrin with a terpyridine external coordination site

We report synthesis and coordination properties of β-alkyl porphyrin derivatives bearing terpyridylphenyl substituents at the meso-position and propionate side chains at the β-positions. Rhenium(I) carbonyl ion was encapsulated not in the core but in the external terpyridyl ligand. Such porphyrin-terpyridine hybrid porphyrins can be potentially available for less-invasive imaging like SPECT.     

Smale's mean value conjecture and the coefficients of univalent functions

We study Smale's mean value conjecture and its connection with the second coefficients of univalent functions. We improve the bound on Smale's constant given by Beardon, Minda and Ng.

     

Determination of Tiny Scatterer#x0027;s Shape by Light Scattering Tomography

We have developed a new method of recognizing the shape of tiny light scatterers by matrix calculation (conjugate gradient method) using the wave field on the objective lens. We describe simulation results for scatterers of about 100 nm and show that they accurately produce the scatterer shape.     

(S)‐4‐Benzyl‐3‐[(R)‐4,4,4‐tri­fluoro‐3‐(4‐methoxy­phenyl)­butanoyl]‐1,3‐oxazolidin‐2‐one

The C atom at the chiral centre of the title compound, C₂₁H₂₀F₃NO₄, takes an R configuration. From this assignment, useful information on the intermediate process of the reaction was deduced.     

GaN外延层中的缺陷对光学性质的影响

用金属有机化合物气相外延（ＭＯＶＥＰ）方法生长具有不同表面形貌的非掺杂ＧａＮ，并对部分样品的外延层表面进行镜面加工．用阴极射线发光、光散射和拉曼散射方法观察ＧａＮ中深能级发光、缺陷散射光分布和拉曼散射光频移．结果表明，缺陷不但影响ＧａＮ的发光和光散射，而且影响拉曼频移     

Observation of 1,6-anhydro-beta-maltose and 1,6-anhydro-beta-D-glucopyranose complexed with rubidium by NMR spectroscopy and electrospray ionization mass spectrometry.

A complex of 1,6-anhydro-beta-maltose with rubidium and that of 1,6-anhydro-beta-D-glucopyranose with rubidium were characterized using 87Rb NMR spectroscopy, diffusion-ordered NMR spectroscopy (DOSY) and electrospray ionization mass spectrometry (ESI-MS). Although subtle differences were observed in the 1H chemical shifts of 1,6-anhydro-beta-maltose in between the presence and absence of rubidium in deuterium oxide, measurements of the spin-lattice relaxation time (T1) of the 87Rb nucleus, the diffusion coefficients of 1,6-anhydro-beta-maltose using 1H DOSY and ESI-MS indicated the complex formation of 1,6-anhydro-beta-maltose with rubidium. The complex formation with rubidium was also identified for 1,6-anhydro-beta-D-glucopyranose using NMR and ESI-MS techniques.