Refine
Has Fulltext
- no (1035) (remove)
Year of publication
- 2013 (1035) (remove)
Document Type
- Article (1035) (remove)
Keywords
- Climate change (6)
- gamma rays: galaxies (6)
- Eye movements (5)
- climate change (5)
- galaxies: active (5)
- Arabidopsis thaliana (4)
- Children (4)
- Development (4)
- Land use change (4)
- Reading (4)
Institute
- Institut für Biochemie und Biologie (182)
- Institut für Physik und Astronomie (152)
- Institut für Geowissenschaften (140)
- Institut für Chemie (99)
- Department Psychologie (63)
- Institut für Romanistik (46)
- Institut für Mathematik (36)
- Department Linguistik (33)
- Institut für Germanistik (28)
- Sozialwissenschaften (27)
Anglizismen im Deutschen
(2013)
Types of Body Shape
(2013)
We demonstrate new fluorophore-labelled materials based on acrylamide and on oligo(ethylene glycol) (OEG) bearing thermoresponsive polymers for sensing purposes and investigate their thermally induced solubility transitions. It is found that the emission properties of the polarity-sensitive (solvatochromic) naphthalimide derivative attached to three different thermoresponsive polymers are highly specific to the exact chemical structure of the macromolecule. While the dye emits very weakly below the LCST when incorporated into poly(N-isopropylacrylamide) (pNIPAm) or into a polyacrylate backbone bearing only short OEG side chains, it is strongly emissive in polymethacrylates with longer OEG side chains. Heating of the aqueous solutions above their cloud point provokes an abrupt increase of the fluorescence intensity of the labelled pNIPAm, whereas the emission properties of the dye are rather unaffected as OEG-based polyacrylates and methacrylates undergo phase transition. Correlated with laser light scattering studies, these findings are ascribed to the different degrees of pre-aggregation of the chains at low temperatures and to the extent of dehydration that the phase transition evokes. It is concluded that although the temperature-triggered changes in the macroscopic absorption characteristics, related to large-scale alterations of the polymer chain conformation and aggregation, are well detectable and similar for these LCST-type polymers, the micro-environment provided to the dye within each polymer network differs substantially. Considering sensing applications, this finding is of great importance since the temperature-regulated fluorescence response of the polymer depends more on the macromolecular architecture than the type of reporter fluorophore.
Sugar-based molecules and polysaccharide biomass can be turned into porous functional carbonaceous products at comparably low temperatures of 400 °C under a nitrogen atmosphere in the presence of an ionic liquid (IL) or a poly(ionic liquid) (PIL). The IL and PIL act as "activation agents" with own structural contribution, and effectively promote the conversion and pore generation in the biomaterials even at a rather low doping ratio (7 wt%). In addition, this "induced carbonization" and pore forming phenomenon enables the preservation of the biotemplate shape to the highest extent and was employed to fabricate shaped porous carbonaceous materials from carbohydrate-based biotemplates, exemplified here with cellulose filter membranes, coffee filter paper and natural cotton. These carbonized hybrids exhibit comparably good mechanical properties, such as bendability of membranes or shape recovery of foams. Moreover, the nitrogen atoms incorporated in the final products from the IL/PIL precursors further improve the oxidation stability in the fire-retardant tests.
Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano)diffraction, energy-dispersive X-ray spectroscopy, and energy- filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.
A polymer analogous reaction for the formation of imidazolium and NHC based porous polymer networks
(2013)
A polymer analogous reaction was carried out to generate a porous polymeric network with N-heterocyclic carbenes (NHC) in the polymer backbone. Using a stepwise approach, first a polyimine network is formed by polymerization of the tetrafunctional amine tetrakis(4-aminophenyl)methane. This polyimine network is converted in the second step into polyimidazolium chloride and finally to a polyNHC network. Furthermore a porous Cu(II)-coordinated polyNHC network can be generated. Supercritical drying generates polymer networks with high permanent surface areas and porosities which can be applied for different catalytic reactions. The catalytic properties were demonstrated for example in the activation of CO2 or in the deoxygenation of sulfoxides to the corresponding sulfides.
The voice of the other : heterotopy and heterology inBernard-Marie Koltes black battles with dogs
(2013)
Intracellular photoactivation of caged-cGMP induces myosin II and actin responses in motile cells
(2013)
Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system.
Coca Cola und "Coolitude"
(2013)
"Mobile mappings" y las literaturas sin residencia fija : Perspectivas de una poética del movimiento
(2013)
Pensamiento nómada
(2013)
Migration und Konvivenz
(2013)
Miedo y catástrofe = Miedo ante la catástrofe : sobre la economía del miedo de cara a la muerte
(2013)
Mors ex nihilo - ein Totentanz von Bert Papenfuss und Jörg Immendorff im Deutschland nach der Wende
(2013)
Vorwort
(2013)
279 bat specimens of 14 species were examined for ectoparasites during the autumnal swarming period in different cave roosts in Albania. A total of 550 ectoparasites were identified belonging to 19 species. The structure of the ectoparasite fauna and the influence of body mass index and body surface area on the parasite load were discussed for the most common bat species (Miniopterus schreibersii, Myotis myotis, M. capaccinii and Rhinolophus ferrumequinum). The ectoparasite fauna of the studied bats in Albania is qualitatively similar to northern Bulgaria (SCHEFFLER, 2011). The bat species Myotis myotis and M. daubentonii are infested with different ectoparasites in the Balkan region during the autumn swarming period than specimens of the same bat species in Central Europe. There is a strong need of further research for most host and ectoparasite species in the entire Balkan region.
Einführung
(2013)
Vorwort
(2013)
Auf dem Weg zu einer regionalisierten Welt? Regionalismus als Element einer multipolaren Ordnung
(2013)
Juan Jose Linz : Nachruf
(2013)
Indira Gandhi : ein Porträt
(2013)