Michalski A.,Polish Academy of Sciences |
Makowski T.,Polish Academy of Sciences |
Biedron T.,Polish Academy of Sciences |
Brzezinski M.,Polish Academy of Sciences |
And 3 more authors.
Polymer (United Kingdom) | Year: 2016
Linear and star-shaped polymers have been synthesized by the controlled ring-opening (ROP) polymerization of l- and d-lactide using 1-methyl-2-hydroxymethyl-3-butylimidazolium tetrafluoroborate and dipentaerythritol as initiators, respectively. To introduce carboxylic end-groups onto the star-shaped polylactides, the reaction of -OH end-groups with succinic anhydride was employed. Afterwards, the starting and modified polylactides were used for the preparation of star-shaped and star-shaped/linear stereocomplexes in 1,4-dioxane and tetrahydrofuran (THF). In these solvents, the stereocomplexes spontaneously precipitated. Star-shaped stereocomplexes with hydroxyl end-groups formed microspheres with diameters ranging from 1 to 4 μm (depending on the initial concentration of sc-PLA components) following precipitation from THF. However, the combined effect of the nature of the end-groups and PLA architecture causes the formation of uniform stereocomplex nanoparticles (∼400 nm) in 1,4-dioxane from the combination of star-shaped PLA functionalized with carboxylic end-groups and linear PLA with ionic liquid end-groups. Microscopic analysis showed that nanometre-sized grains of stereocomplexes (∼30 nm) aggregated to form larger stereocomplex nanoparticles. It was observed that the combination of three factors, i.e., the end-group interactions, architecture of the enantiomeric components, and basicity of the solvent in which the stereocomplexes are prepared, influences the properties and morphology of the final stereocomplex-based materials. © 2016 Elsevier Ltd. All rights reserved.
Kraudzun T.,FreieUniversitat Berlin
Central Asian Survey | Year: 2014
This paper deals with the strategies of households living in a peripheral high-mountain region in order to cope with the post-Soviet energy crisis. The Soviet modernization project failed at connecting the region to the grid, and imported coal for heating and fuel for producing electric energy at high costs over long distances. After the collapse of this alimentation system, people have substituted energy demands with wood and shrubs, and used increasingly available low-cost Chinese solar equipment to produce electrical energy. International development actors have failed to increase acceptance for energy efficiency technologies. Despite the Pamirs' high potential for solar and wind energy and decreasing installation costs, Soviet-style state planning of energy infrastructure still favours big hydropower stations, despite their high (social) costs and the limited potential on the Pamir plateau. The paper will discuss bottom-up effects of household decisions and top-down strategies as potentials and obstacles for a sustainable energy supply in the Pamirs. © 2014 Southseries Inc.
Iles G.N.,Helmholtz Center Berlin |
Iles G.N.,Australian Nuclear Science and Technology Organization |
Peetermans S.,Paul Scherrer Institute |
Schorr S.,Helmholtz Center Berlin |
And 2 more authors.
Physics Procedia | Year: 2015
The Fast Acquisition Laue Camera for Neutrons (FALCON) is a thermal neutron Laue diffractometer at HZB in Berlin. The instrument comprises two scintillator plate detectors coupled to four iCCD cameras each. One detector is placed in the backscattering position, enabling neutrons to pass through the centre of the detector box. The second detector is free to be placed either in the direct transmission position, or rotated to positions around the sample. The image-intensified CCDs, supplied by Photonic Science Ltd as components of the detector units, are capable of obtaining 20-bit digitization Laue images in under ten seconds. Whilst our instrument will be used as a diffractometer primarily for crystal structure determination, the configuration of the detectors is similar to ICON at PSI in Switzerland, especially in their 'double detector set-up'. In 2015 FALCON enters the commissioning phase whereby one of our activities will be to calibrate the detector units using CONRAD, the cold neutron imaging instrument of HZB. CONRAD will be used to characterise those factors which affect the total efficiency of the detectors i.e. cameras, lenses, CCD chips and the scintillators themselves e.g. homogeneity of the scintillator plate thickness. © 2015 The Authors.
Studies on the effect of an Enterococcus faecium probiotic on T cell populations in peripheral blood and intestinal epithelium and on the susceptibility to Salmonella during a challenge infection with Salmonella Typhimurium in piglets
Mafamane H.,FreieUniversitat Berlin |
Szabo I.,German Federal Institute for Risk Assessment |
Schmidt M.F.G.,FreieUniversitat Berlin |
Filter M.,Charite - Medical University of Berlin |
And 3 more authors.
Archives of Animal Nutrition | Year: 2011
Although Enterococcus faecium is used as a probiotic feed supplement in animal production, feeding of the bacterium to piglets resulted in a more severe infection with Salmonella Typhimurium DT104 during a challenge experiment. To enlighten the mode of action by which E. faecium affected the piglets' health, we investigated the influence of the probiotic bacterium on the development of intestinal and circulating immune cells during a challenge experiment with S.Typhimurium DT104. To minimise varying impacts of the maternal immunity on the course of infection, only piglets were implemented that descended from Salmonella-free sows. In addition, the potency of purified blood and intraepithelial immune cells to control the growth of Salmonella was tested in vitro. In animals treated with E. faecium, a reduction of intraepithelial CD8αβ T cells, reduced circulating CD8αβ T cells and a less efficient control of intracellular Salmonella growth, mediated by peripheral blood mononuclear cells, were observed. © 2011 Copyright Taylor and Francis Group, LLC.