Manchester Metropolitan University

About: Manchester Metropolitan University is a education organization based out in Manchester, Manchester, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 5435 authors who have published 16202 publications receiving 442561 citations. The organization is also known as: Manchester Polytechnic & MMU.

Early-response gene signalling is induced by angiogenic oligosaccharides of hyaluronan in endothelial cells. Inhibition by non-angiogenic, high-molecular-weight hyaluronan.

Abstract: The degradation products of hyaluronan are known to stimulate endothelial-cell proliferation and to promote neovascularization associated with angiogenesis, whilst native high-molecular-weight hyaluronan is inhibitory to these processes. To investigate the cellular signalling pathways coupled to hyaluronan-induced responses in angiogenesis, we have analyzed early-response gene expression in vitro, in cultured bovine aortic endothelial cells. Angiogenic oligosaccharides of hyaluronan induced rapid transient up-regulation of the immediate early genes c-fos, c-jun, jun-B, Krox-20 and Krox-24. In contrast, native hyaluronan when used alone failed to elicit a significant change in expression of any of the genes tested, and when used in combination with angiogenic oligosaccharides of hyaluronan, gave a dose-dependent inhibition of induced gene expression. However, prior addition of angiogenic hyaluronan, as little as one minute before addition of high-molecular-weight hyaluronan, abrogated this inhibition, suggesting that positive or negative responses associated with hyaluronan signalling are integrated at a very early stage following receptor binding. Conversely, prior addition of high-molecular-weight hyaluronan led to an irreversible block in gene expression and proliferative response. These data are consistent with native hyaluronan antagonizing the angiogenic response in part by blocking a signalling cascade at or immediately following ligand-receptor interaction. Finally, we demonstrated that chronic exposure to oligosaccharides of hyaluronan is essential for cell proliferation, indicating that short-term immediate early-gene signalling is insufficient to elicit the proliferation of endothelial cells.

A carbon quantum dot decorated RuO2 network: outstanding supercapacitances under ultrafast charge and discharge

Abstract: Carbon quantum dots (CQDs) due to their unique properties have recently attracted extensive attention from researchers in many fields. In the present work, a new application in the form of a CQD-based hybrid as an excellent electrode material for supercapacitors is reported for the first time. The CQDs are fabricated by a facile chemical oxidation method following which they are thermally reduced, and further decorated with RuO2 to obtain the composites. The hybrid exhibits a specific capacitance of 460 F g−1 at an ultrahigh current density of 50 A g−1 (41.9 wt% Ru loading), and excellent rate capability (88.6, 84.2, and 77.4% of capacity retention rate at 10, 20, and 50 A g−1 compared with 1 A g−1, respectively). Surprisingly, the hybrid shows exceptional cycling stability with 96.9% capacity retention over 5000 cycles at 5 A g−1. Such remarkable electrochemical performances can be primarily ascribed to the significantly enhanced utilization of RuO2 achieved by the efficient dispersion of tiny reduced CQDs and the formation of a CQD-based hybrid network structure that can facilitate the fast charge transport and ionic motion during the charge–discharge process. Additionally, the contact resistance at the interface between active materials and current collectors is concluded to be a key factor in determining the performance of the hybrid. These results above demonstrate the great potential of CQD-based hybrid materials in the development of high-performance electrode materials for supercapacitors.