Functional comparison of the endothelial nitric oxide synthase Glu298Asp polymorphic variants in human endothelial cells

The G894T endothelial nitric oxide synthase (eNOS) polymorphism results in a Glu to Asp substitution at position 298. This position is located externally on the protein and as the regulation of eNOS is dependent on its subcellular localization and interaction with modulatory proteins, we aimed to address whether the substitution of Asp at 298 had any effect on these mechanisms. Initially, we developed a novel method to accurately determine molar quantities of each variant by expressing them as green fluorescent protein (GFP) fusion proteins and using recombinant adenoviruses to facilitate transient infection of human microvascular endothelial cells. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting of eNOS298Asp revealed a 135-kDa proteolytic fragment which was not present with eNOS298Glu. This proteolysis was prevented by using LDS buffer confirming that this differential cleavage is an artefact of sample preparation and unlikely to occur intracellularly. Nitric oxide was measured following stimulation with calcium ionophore or oestrogen in the presence of varying sepiapterin concentrations. GFP fluorescence was used to quantify the amount of fusion protein and calculate intracellular specific activity. There was no significant difference in intracellular specific activity between Glu298 and Asp298 eNOS in response to calcium ionophore or oestrogen. Tetrahydrobiopterin supplementation increased eNOS activity of both variants in an identical manner. The presence of the GFP also facilitated the visualization of the variants by confocal microscopy and demonstrated that both localized to the plasma membrane and the Golgi. These findings demonstrate that the Asp substitution at 298 does not have a major effect in modulating eNOS activity in vivo.

A 7000 yr perspective on volcanic ash clouds affecting northern Europe

The ash cloud resulting from the 2010 eruption of Eyjafjöll caused severe disruption to air travel across Europe but as a geological event, it is not unprecedented. Analysis of peat and lake sediments from northern Europe has revealed the presence of microscopic layers of Icelandic volcanic ash (tephra). These sedimentary records, together with historical records of Holocene ash falls, demonstrate that Icelandic volcanoes have generated substantial ash clouds that reached northern Europe many times. Here we present the first comprehensive compilation of sedimentary and historical records of ash-fall events in northern Europe, spanning the last 7000 years. Within this period ten tephra layers have been identified in the Faroe Islands, 14 in Great Britain, 11 in Germany, 38 in Scandinavia and 33 in Ireland. Seven ash fall events have been historically documented prior to the Eyjafjöll 2010 event. Ash fall events appear to be more frequent in the last 1500 years, but it is unclear whether this reflects a true increase in eruption frequency or dispersal, or is an artefact of the records themselves or the way they have been generated. In the last 1,000 years, volcanic ash clouds reached Northern Europe with a mean return interval of 53 ± 8 years (the range of return intervals is between 6 and 112 years). Modelling using the ash records for the last millennium indicates that for any 10 year period there is a 17% probability of tephra fallout event in Northern Europe. These values must be considered as conservative estimates due to the nature of tephra capture and preservation in the sedimentary record.

A scheme for entanglement extraction from a solid

Some thermodynamical properties of solids, such as heat capacity and magnetic susceptibility, have recently been shown to be linked to the amount of entanglement in a solid. However, this entanglement may appear a mere mathematical artefact of the typical symmetrization procedure of many-body wavefunction in solid state physics. Here we show that this entanglement is physical, demonstrating the principles of its extraction from a typical solid-state system by scattering two particles off the system. Moreover, we show how to simulate this process using present day optical lattice technology. This demonstrates not only that entanglement exists in solids but also that it can be used for quantum information processing or as a test of Bell's inequalities.

Reinforced concrete wall construction formed with OSB:First published use in the United Kingdom and acknowledged by Terry Pawson Architects as the source of inspiration for the internal concrete finish of the 2010 Carlow VISUAL Centre for Contemporary Art.

The artefact was published in the following :

Bennett, D., (October 2007), Architectural Insitu Concrete, RIBA Publishing, London, , ISBN 124-3671-245, pp 101-103

Bennett, D., (2008), Concrete Elegance Four, London, Concrete Centre and RIBA Publishing, pp cover, c, 4, 9-12 & back.

Stacey, Professor M., (2011) Concrete: a studio design guide, London, Concrete Centre and RIBA Publishing, pp74-75.