University of Portsmouth

About: University of Portsmouth is a education organization based out in Portsmouth, Portsmouth, United Kingdom. It is known for research contribution in the topics: Population & Galaxy. The organization has 5452 authors who have published 14256 publications receiving 424346 citations. The organization is also known as: Portsmouth and Gosport School of Science and Art & Portsmouth and Gosport School of Science and the Arts.

Factors influencing gel-strengthening at the mucoadhesive-mucus interface.

Abstract: — Mechanical spectroscopy was used to examine some of the factors that may affect mucus gel strengthening: the effect of adding various concentrations of sodium chloride; mucoadhesive polymer molecular weight and its concentration; and the introduction of anionic, cationic and neutral polymers. A reduction in the storage modulus of the mucus/mucoadhesive mixture was observed with the introduction of sodium chloride. A poly(acrylic acid) with a molecular weight of 750 kDa gave the optimum mucus gel strengthening effect relative to other molecular weights. An anionic polymer was found to strengthen the mucus gel much more than a neutral or cationic polymer. It was proposed that the gel strengthening effect could be due to the formation of hydrogen bonded intermolecular complexes between the mucoadhesive and the mucus molecules. Furthermore, the complex formed is influenced by the ionic strength of the environment, and the molecular weight, nature and concentration of the mucoadhesive. In all cases the changes in the rheological properties of the mixes could be correlated directly to the strength of mucoadhesion reported in previous studies.

Mineral resources and conflicts in DRC: a case of ecological fallacy?

Abstract: We estimate the impact of geo-located mining concessions on the number of conflict events recorded in the Democratic Republic of the Congo between 1997 and 2007. Instrumenting the variable of interest with historical concessions interacted with changes in international prices of minerals, we unveil an ecological fallacy: Whereas concessions have no effect on the number of conflicts at the territory level (lowest administrative unit), they do foster violence at the district level (higher administrative unit). We develop and validate empirically a theoretical model where the incentives of armed groups to exploit and protect mineral resources explain our empirical findings.