The University of Göttingen , known informally as Georgia Augusta, is a Public comprehensive research university in the city of Göttingen, Germany. Founded in 1734 by George II, King of Great Britain and Elector of Hanover and starting classes in 1737, the university is the oldest in the state of Lower Saxony, and also the biggest in student enrollment, which stands at around 26,000. The university is highly renowned and respected both in Germany and in the world and has shaped Göttingen into a university city with a high student and faculty population. Wikipedia.
Rizzoli S.O.,University of Gottingen
EMBO Journal | Year: 2014
Synaptic vesicle recycling is one of the best-studied cellular pathways. Many of the proteins involved are known, and their interactions are becoming increasingly clear. However, as for many other pathways, it is still difficult to understand synaptic vesicle recycling as a whole. While it is generally possible to point out how synaptic reactions take place, it is not always easy to understand what triggers or controls them. Also, it is often difficult to understand how the availability of the reaction partners is controlled: how the reaction partners manage to find each other in the right place, at the right time. I present here an overview of synaptic vesicle recycling, discussing the mechanisms that trigger different reactions, and those that ensure the availability of reaction partners. A central argument is that synaptic vesicles bind soluble cofactor proteins, with low affinity, and thus control their availability in the synapse, forming a buffer for cofactor proteins. The availability of cofactor proteins, in turn, regulates the different synaptic reactions. Similar mechanisms, in which one of the reaction partners buffers another, may apply to many other processes, from the biogenesis to the degradation of the synaptic vesicle. Silvio Rizzoli reviews the different steps and mechanisms involved in synaptic vesicle biogenesis and recycling. © 2014 The Authors.
Hegerfeldt G.C.,University of Gottingen
Physical Review Letters | Year: 2013
A remarkably simple result is derived for the minimal time Tminâ ¡ required to drive a general initial state to a final target state by a Landau-Zener-type Hamiltonian or, equivalently, by time-dependent laser driving. The associated protocol is also derived. A surprise arises for some states when the interaction strength is bounded by a constant c. Then, for large c, the optimal driving is of type bang-off-bang and for increasing c one recovers the unconstrained result. However, for smaller c the optimal driving can suddenly switch to bang-bang type. We discuss the notion of quantum speed limit time. © 2013 American Physical Society.
Sheldrick G.M.,University of Gottingen
Acta Crystallographica Section A: Foundations of Crystallography | Year: 2015
The new computer program SHELXT employs a novel dual-space algorithm to solve the phase problem for single-crystal reflection data expanded to the space group P1. Missing data are taken into account and the resolution extended if necessary. All space groups in the specified Laue group are tested to find which are consistent with the P1 phases. After applying the resulting origin shifts and space-group symmetry, the solutions are subject to further dual-space recycling followed by a peak search and summation of the electron density around each peak. Elements are assigned to give the best fit to the integrated peak densities and if necessary additional elements are considered. An isotropic refinement is followed for non-centrosymmetric space groups by the calculation of a Flack parameter and, if appropriate, inversion of the structure. The structure is assembled to maximize its connectivity and centred optimally in the unit cell. SHELXT has already solved many thousand structures with a high success rate, and is optimized for multiprocessor computers. It is, however, unsuitable for severely disordered and twinned structures because it is based on the assumption that the structure consists of atoms. © 2015 International Union of Crystallography.
Wenger O.S.,University of Gottingen
Chemical Society Reviews | Year: 2011
Phenylene oligomers represent a borderline case between very strongly π-conjugated molecular wires such as oligo-p-phenylene vinylenes and saturated molecular bridges. Even subtle chemical modifications of phenylene oligomers can therefore have a strong impact on charge transfer rates and mechanisms. On the basis of recently published selected case studies, this tutorial review discusses the key factors that affect charge transfer kinetics in phenylene oligomers with particular focus on the role of donor-bridge energy matching. Selected examples of triplet-triplet energy transfer reactions across phenylene oligomers are also discussed. © 2011 The Royal Society of Chemistry.
Ackermann L.,University of Gottingen
Chemical Reviews | Year: 2011
The development and scope of carboxylates as cocatalysts in transition-metal-catalyzed C-H functionalizations is reviewed. Ryabov and co-workers probed the mechanism of ortho-palladation reactions with N,N-dimethylbenzylamines (DMBA-H, 5) as substrate. Jones and coworkers performed detailed mechanistic studies on the formation of irida- and rhodacycles derived from electron-rich and electron-poor imines, which indicated [Cp*M(OAc)]+ (M = Rh, Ir) to be the key intermediates for acetate-assisted electrophilic activations via transition state. Intermolecular palladium-catalyzed direct benzylations of various five-membered heteroarenes through carboxylate assistance were reported by Fagnou and Lapointe. Dixneuf and Pozgan also reported a ruthenium-catalyzed direct arylation of one 2-phenylpyridine with KOAc as additive.