Copper(0) in the Ullmann heterocycle-aryl ether synthesis of 4-phenoxypyridine using multimode microwave heating

The action of nanoparticulate copper catalysts with a mean particle size of 10 nm in the Ullmann ether synthesis is reported using multimode microwave heating and employing stable chloropyridine salts and unactivated phenol, with stabilized copper nanoparticles outperforming other copper catalysts in terms of stability and reusability.     

Determining the Surface Tension of Microliter Amounts of Liquid

We describe a method for determining the surface tension of liquids by measuring the pull-off force between curved surfaces with a bridging droplet. The technique is useful for cases when only very small amounts of liquid are available, as in medical and biological applications. Data on the surface tension of saliva samples are in agreement with literature values. Copyright 2000 Academic Press.     

A severely interrupted germanate zeolite framework synthesised from isolated double four-ring units

A new germanate zeolite framework has been prepared by first determining the reaction conditions required to prepare a molecular analogue of the zeolite double four-ring secondary building unit and then altering the conditions so as to encourage condensation of these units. The resultant material is a severely interrupted solid showing an unusual two dimensional channel system. It is also one of the most open frameworks yet discovered. The material was characterised using single crystal X-ray diffraction at a synchrotron source and solid state magic angle spinning NMR.     

1H-NMR relaxation times and water content of red blood cells from chronic alcoholic patients during withdrawal

Red blood cell proton nmr, T1 and T2 times, and water content were measured for normal control subjects and thirteen patients with chronic alcoholism during the withdrawal phase. T1 and T2 were significantly increased without significant alteration in cell water content. The relaxation times were more markedly affected in those with symptoms of delirium tremens. These findings suggest that the intracellular free:bound water states rather than water content is the more likely explanation for these changes. The results are discussed in relation to similar findings obtained from in vivo studies in man and in vitro studies in animals.     

A New Method for Determining the Composition of Core–Shell Nanoparticles via Dual‐EDX+EELS Spectrum Imaging

Simultaneously acquired microanalytical X‐ray and electron energy loss signals are obtained from a bimetallic core–shell nanoparticle system (FePt@Fe₃O₄). The signals are decomposed using independent component analysis and the extracted components are used to separately quantify the composition of the spatially overlapping core and shell phases in the nanoheterostructure. The utilization of the complementary strengths of energy dispersive X‐ray and electron energy‐loss spectroscopy microanalysis has enabled the quantification of both light and heavy elements in a single spectrum image acquisition.