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The overhead of network communication creates a significant performance gap between local and distributed query processing in parallel main-memory database systems. We introduce a novel query engine designed to close this gap. It exploits locality in the data placement, leverages high-speed networks, and avoids the load imbalance caused by skew. A prototypical implementation for the high-performance in-memory database system HyPer outperforms competing systems in the renowned TPC-H benchmark. Teure Netzwerkkommunikation führt zu einer erheblichen Leistungslücke zwischen lokaler und verteilter Anfrageverarbeitung in parallelen Hauptspeicher-Datenbanksystemen. Wir präsentieren den Entwurf für eine neue verteilte Anfrageeinheit um diese Lücke zu schließen. Diese passt sich an die verfügbare Netzwerkbandbreite sowie unerwartete Eigenschaften der Daten an. Ein Prototyp für das hochperformante Hauptspeicher-Datenbanksystem HyPer schlägt konkurrierende Systeme im anerkannten TPC-H Benchmark.

Histamine is a neurotransmitter involved in a number of physiological and neuronal functions. In mammals, such as humans, and rodents, the histaminergic neurons found in the tuberomamillary nucleus project widely throughout the central nervous system. Histamine acts as positive modulator of \(GABA_{A}\) receptors \((GABA_{A}Rs)\) and, in high concentrations (10 mM), as negative modulator of the strychnine-sensitive glycine receptor. However, the exact molecular mechanisms by which histamine acts on \(GABA_{A}Rs\) are unknown. In our study, we aimed to identify amino acids potentially involved in the modulatory effect of histamine on \(GABA_{A}Rs\). We expressed \(GABA_{A}Rs\) with 12 different point mutations in Xenopus laevis oocytes and characterized the effect of histamine on GABA-induced currents using the two-electrode voltage clamp technique. Our data demonstrate that the amino acid residues \(\beta\)2(N265) and \(\beta\)2(M286), which are important for modulation by propofol, are not involved in the action of histamine. However, we found that histamine modulation is dependent on the amino acid residues \(\alpha\)1(R120), \(\beta\)2(Y157), \(\beta\)2(D163), \(\beta\)3(V175), and \(\beta\)3(Q185). We showed that the amino acid residues \(\beta\)2(Y157) and \(\beta\)3(Q185) mediate the positive modulatory effect of histamine on GABA-induced currents, whereas \(\alpha\)1(R120) and \(\beta\)2(D163) form a potential histamine interaction site in \(GABA_{A}Rs\).

G protein-coupled receptors (GPCRs) form the largest family of membrane receptors in the human genome. Advances in membrane protein crystallization so far resulted in the determination of 24 receptors available as high-resolution atomic structures. We performed the first phylogenetic analysis of GPCRs based on the available set of GPCR structures. We present a new phylogenetic tree of known human rhodopsin-like GPCR sequences based on this structure set. We can distinguish the three separate classes of small-ligand binding GPCRs, peptide binding GPCRs, and olfactory receptors. Analyzing different structural subdomains, we found that small molecule binding receptors most likely have evolved from peptide receptor precursors, with a rhodopsin/S1PR1 ancestor, most likely an ancestral opsin, forming the link between both classes. A light-activated receptor therefore seems to be the origin of the small molecule hormone receptors of the central nervous system. We find hints for a common evolutionary path of both ligand binding site and central sodium/water binding site. Surprisingly, opioid receptors exhibit both a binding cavity and a central sodium/water binding site similar to the one of biogenic amine receptors instead of peptide receptors, making them seemingly prone to bind small molecule ligands, e.g. opiates. Our results give new insights into the relationship and the pharmacological properties of rhodopsin-like GPCRs.

Ceramic layers, such as yttria-stabilized zirconia or scandia-stabilized zirconia, used for functional layers of solid oxide fuel cells, i.e. the gas tight oxygen ion conductive electrolyte or as ceramic component in the porous cermet anode, were obtained by the Solution Precursor Plasma Spray (SPPS) process. The influence of different solvent types on microstructure was analyzed by comparison of coatings sprayed with water-based solution to ethanol-based one. Use of solvent with low surface tension and low boiling point enhances splat formation, coating micro-structure and crystalline structure. Parameter adjustment to receive coatings from nitrate solutions with ethanol as solvent was carried out. Results of Raman spectroscopy indicate that an intermediate of both nitrates (zirconyl and scandium nitrate hydrate) was deposited.

In dieser Arbeit wurden Modelle von G-Protein gekoppelten Rezeptoren (GPCR) und mikrobiellen Rhodopsinen mittels Molekulardynamik(MD)-Simulationen untersucht. Ein Verfahren zu Erstellung von für MD-Simulationen geeigneten GPCR-Homologiemodellen wurde entwickelt und am Beispiel von Rhodopsin und dem \(\beta_{2}\)-adrenergen Rezeptors validiert. Modelle der olfaktorischen Rezeptoren hOR2AG1 und hOR51E2 wurden erstellt. Die Ligandenbindestelle und der Ligandenspezifitätsfilter von hOR2AG1 wurden ermittelt. An hOR51E2 wurde die Einbindung von \(\beta\)-Ionon untersucht. In dynamischen Modellen mikrobieller Rhodopsine wurde die Verteilung interner Wassermoleküle analysiert: Für die Protonenabgabegruppe von Bakteriorhodopsin zeigte sich ein direktionaler Abgabemechanismus vergleichbar einer elektronischen Diode. Ein Protonenleiter aus Wassermolekülen zwischen Asp96 und Lys216 konnte identifiziert werden. Dynamische Modelle von Channelrhodopsin I zeigten einen möglichen proteininternen Protonenleiter.

The Super-Peer Selection Problem is an optimization problem in network topology construction. It may be cast as a special case of a Hub Location Problem, more exactly an Uncapacitated Single Allocation p-Hub Median Problem with equal weights. We show that this problem is still NP-hard by reduction from Max Clique. Das Super-Peer-Selektions-Problem ist ein Optimierungsproblem der Netzwerktopologiekonstruktion. Es kann als Spezialfall eines Hub-Location-Problems aufgefaßt werden, genauer das Uncapacitated Single Allocation p-Hub Median Problem mit gleichen Gewichten. Wir zeigen, daß dieses Problem noch immer NP-schwer ist durch Reduktion von Max-Clique.