206 research outputs found
Quantum corrections to mass and central charge of supersymmetric solitons
We review some recent developments in the subject of quantum corrections to
soliton mass and central charge. We consider in particular approaches which use
local densities for these corrections, as first discussed by Hidenaga
Yamagishi. We then consider dimensional regularization of the supersymmetric
kink in 1+1 dimensions and an extension of this method to a 2+1-dimensional
gauge theory with supersymmetric abelian Higgs vortices as the solitons.Comment: 41 pages. Contribution to the Hidenaga Yamagishi commemorative volume
of Physics Reports, edited by E. Witten and I. Zahe
Saccharomyces cerevisiae–Based Platform for Rapid Production and Evaluation of Eukaryotic Nutrient Transporters and Transceptors for Biochemical Studies and Crystallography
To produce large quantities of high quality eukaryotic membrane proteins in Saccharomyces cerevisiae, we modified a high-copy vector to express membrane proteins C-terminally-fused to a Tobacco Etch Virus (TEV) protease detachable Green Fluorescent Protein (GFP)-8His tag, which facilitates localization, quantification, quality control, and purification. Using this expression system we examined the production of a human glucose transceptor and 11 nutrient transporters and transceptors from S. cerevisiae that have not previously been overexpressed in S. cerevisiae and purified. Whole-cell GFP-fluorescence showed that induction of GFP-fusion synthesis from a galactose-inducible promoter at 15°C resulted in stable accumulation of the fusions in the plasma membrane and in intracellular membranes. Expression levels of the 12 fusions estimated by GFP-fluorescence were in the range of 0.4 mg to 1.7 mg transporter pr. liter cell culture. A detergent screen showed that n-dodecyl-ß-D-maltopyranoside (DDM) is acceptable for solubilization of the membrane-integrated fusions. Extracts of solubilized membranes were prepared with this detergent and used for purifications by Ni-NTA affinity chromatography, which yielded partially purified full-length fusions. Most of the fusions were readily cleaved at a TEV protease site between the membrane protein and the GFP-8His tag. Using the yeast oligopeptide transporter Ptr2 as an example, we further demonstrate that almost pure transporters, free of the GFP-8His tag, can be achieved by TEV protease cleavage followed by reverse immobilized metal-affinity chromatography. The quality of the GFP-fusions was analysed by fluorescence size-exclusion chromatography. Membranes solubilized in DDM resulted in preparations containing aggregated fusions. However, 9 of the fusions solubilized in DDM in presence of cholesteryl hemisuccinate and specific substrates, yielded monodisperse preparations with only minor amounts of aggregated membrane proteins. In conclusion, we developed a new effective S. cerevisiae expression system that may be used for production of high-quality eukaryotic membrane proteins for functional and structural analysis
Genetic Analysis of Signal Generation by the Rgt2 Glucose Sensor of <i>Saccharomyces cerevisiae</i>
Det moderne fængselsvæsens gennembrud i Danmark - Opdragelse, moral og Føngselskommisionen af 1840
Reform and Research: Re-connecting Prison and Society in the 21st Century
IIn this contribution I briefly outline some of the historical and current trends in prison research and question how a prison researcher can work towards influencing policy and practice. I discuss the current role of ‘what works’ research and the way it is sometimes utilized in a time of penal populism and rising prison populations. I argue in favour of a broader approach which recognizes the wider societal effects of imprisonment and I provide a concrete example of how one can attempt to plan research and project work in order to facilitate progression from research and knowledge production to action and implementation. Finally I discuss some of the scientific and ethical implications which can arise when working with reform and implementation projects
Anmeldelse af Ann-Christine Petersson Hjelm: Fängelset som välfärdsbygge
Review of Ann-Christine Petersson Hjelm: Fängelset som välfärdsbygg
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