Showing papers by "Simon Brown published in 2002"
TL;DR: It is proposed that CD31 (also known as platelet-endothelial cell adhesion molecule-1, PECAM-1) is an example of a cell-surface molecule that prevents phagocyte ingestion of closely apposed viable cells by transmitting ‘detachment’ signals, and which changes function on apoptosis, promoting tethering of dying cells to phagocytes.
Abstract: Macrophage recognition and ingestion of 'self' cells undergoing apoptosis in vivo protects tissues from the toxic contents of dying cells and modulates macrophage regulation of inflammatory and immune responses. However, the complex molecular mechanisms mediating macrophage discrimination between viable and apoptotic cells are poorly understood. In particular, little is known of why viable nucleated cells are not engulfed by macrophages. To reveal active repulsion of viable cells and to seek specific capture or 'tethering' of apoptotic cells, we studied macrophage binding of viable and apoptotic leukocytes under conditions of flow. We found that homophilic ligation of CD31 (ref. 4) on viable leukocytes promoted their active, temperature-dependent detachment under low shear, whereas such CD31-mediated detachment was disabled in apoptotic leukocytes, promoting tight binding and macrophage ingestion of dying cells. Here we propose that CD31 (also known as platelet-endothelial cell adhesion molecule-1, PECAM-1) is an example of a cell-surface molecule that prevents phagocyte ingestion of closely apposed viable cells by transmitting 'detachment' signals, and which changes function on apoptosis, promoting tethering of dying cells to phagocytes.
379 citations
Patent•
20 Aug 2002
TL;DR: In this article, a method of forming a conducting nanowire between two contacts on a substrate surface is proposed, where a plurality of nanoparticles are deposited on the substrate in the region between the contacts, and the single nanowires running substantially between the two contacts is formed by either by monitoring the conduction between the contact and ceasing deposition at the onset of conduction, and/or modifying the substrate to achieve, or taking advantage of pre-existing topographical features which will cause the nanoparticles to form the nanowired.
Abstract: The invention relates to a method of forming a conducting nanowire between two contacts on a substrate surface wherein a plurality of nanoparticles is deposited on the substrate in the region between the contacts, and the single nanowire running substantially between the two contacts is formed by either by monitoring the conduction between the contacts and ceasing deposition at the onset of conduction, and/or modifying the substrate to achieve, or taking advantage of pre-existing topographical features which will cause the nanoparticles to form the nanowire. The resultant conducting nanowires are also claimed as well as devices incorporating such nanowires.
105 citations
TL;DR: It is demonstrated, both by experiment and by simulation, that for small contact separations the percolation threshold is shifted to extremely low surface coverages.
Abstract: Atomic clusters have been deposited between lithographically defined contacts with nanometer scale separations. The design of the contacts is based on an appropriate application of percolation theory to conduction in cluster deposited devices and allows finite-size effects to be clearly observed. It is demonstrated, both by experiment and by simulation, that for small contact separations the percolation threshold is shifted to extremely low surface coverages. The selected rectangular contact geometry ensures that wirelike structures are formed close to the percolation threshold.
81 citations