Regeringsautonomi og delegeringstab i dansk EU-politik: Et principal-agent teoretisk perspektiv

Where do states’ positions on EU-integration come from? Despite a large number of studies we simply do not know which factors determine states’ positions in specific cases and why. This article analyses position making between ‘governments’ and ‘parliaments’ during the Maastricht Treaty negotiations. Furthermore, an analysis of the role of information asymmetries as intermediating factors in generating ‘influence on position’ will be carried out. The question asked is: Do governments enjoy relative autonomy vis-à-vis the Folketing that enables them to develop ‘positions’ they feel are in ‘the national interest’ or is Parliament able to control government behavior? The conclusions indicate that Parliaments control governmental positions, but also that governments, are able to exploit the negotiations to pursue certain ‘policy drifts’. The research design used is an in-dept single case study that analyses the level of inFluence on a multitude of different issues varied over the conflict level between the actors.

Finite-temperature behavior of the Bose polaron

We consider a mobile impurity immersed in a Bose gas at finite temperature. Using perturbation theory valid for weak coupling between the impurity and the bosons, we derive analytical results for the energy and damping of the impurity for low and high temperatures, as well as for temperatures close to the critical temperature $T_c$ for Bose-Einstein condensation. These results show that the properties of the impurity vary strongly with temperature. In particular, the energy exhibits a non-monotonic behavior close to $T_c$, and the damping rises sharply close to $T_c$. We argue that this behaviour is generic for impurities immersed in an environment undergoing a phase transition that breaks a continuous symmetry. Finally, we discuss how these effects can be detected experimentally.Comment: 10 pages and 6 figure

Investigation of enzyme-sensitive lipid nanoparticles for delivery of siRNA to blood–brain barrier and glioma cells

Clinical applications of siRNA for treating disorders in the central nervous system require development of systemic stable, safe, and effective delivery vehicles that are able to cross the impermeable blood–brain barrier (BBB). Engineering nanocarriers with low cellular interaction during systemic circulation, but with high uptake in targeted cells, is a great challenge and is further complicated by the BBB. As a first step in obtaining such a delivery system, this study aims at designing a lipid nanoparticle (LNP) able to efficiently encapsulate siRNA by a combination of titratable cationic lipids. The targeted delivery is obtained through the design of a two-stage system where the first step is conjugation of angiopep to the surface of the LNP for targeting the low-density lipoprotein receptor-related protein-1 expressed on the BBB. Second, the positively charged LNPs are masked with a negatively charged PEGylated (poly(ethylene glycol)) cleavable lipopeptide, which contains a recognition sequence for matrix metalloproteinases (MMPs), a class of enzymes often expressed in the tumor microenvironment and inflammatory BBB conditions. Proteolytic cleavage induces PEG release, including the release of four glutamic acid residues, providing a charge switch that triggers a shift of the LNP charge from weakly negative to positive, thus favoring cellular endocytosis and release of siRNA for high silencing efficiency. This work describes the development of this two-stage nanocarrier-system and evaluates the performance in brain endothelial and glioblastoma cells with respect to uptake and gene silencing efficiency. The ability of activation by MMP-triggered dePEGylation and charge shift is demonstrated to substantially increase the uptake and the silencing efficiency of the LNPs