1,4-Bis(4-nitrosophenyl)piperazine: novel bridging ligand in dinuclear complexes of rhodium(III) and iridium(III).

The synthesis, spectroscopic characterization and crystal structures of the first 1,4-bis(4-nitrosophenyl)piperazine (BNPP) (4) bridged dinuclear complexes of rhodium(III) and iridium(III) are presented. The reaction of the μ2-halogenido-bridged dimers [(η5-C5Me5)IrX2]2 [X = Cl (5a), Br (5b), I (5c)] and [(η5- C5Me5)RhCl2]2 (6a) with 4 yields the dinuclear complexes [(η5-C5Me5)IrX2]2-BNPP (7a–c) and [(η5-C5Me5)RhCl2]2-BNPP (8a). All new compounds were characterized by their NMR, IR and mass spectra. The X-ray structure analyses of the obtained half-sandwich complexes revealed a slightly distorted pseudo-octahedral configuration (“three-legged pianostool”) for the metal(III) centers. The bridging BNPP ligand is σ-N coordinated by both nitroso groups and shows different conformations of the piperazine ring depending on the solvent used for crystallization. Moreover the crystal structures of 1,4-bis(4-nitrosophenyl)piperazine (4) and its precursor 1,4-diphenylpiperazine (3) are reported

An Upper Bound on the Number of Extreme Shortest Paths in Arbitrary Dimensions

Graphs with multiple edge costs arise naturally in the route planning domain when apart from travel time other criteria like fuel consumption or positive height difference are also objectives to be minimized. In such a scenario, this paper investigates the number of extreme shortest paths between a given source-target pair s, t. We show that for a fixed but arbitrary number of cost types d ? 1 the number of extreme shortest paths is in n^O(log^{d-1}n) in graphs G with n nodes. This is a generalization of known upper bounds for d = 2 and d = 3

Preference-Based Trajectory Clustering - An Application of Geometric Hitting Sets

In a road network with multicriteria edge costs we consider the problem of computing a minimum number of driving preferences such that a given set of paths/trajectories is optimal under at least one of these preferences. While the exact formulation and solution of this problem appears theoretically hard, we show that in practice one can solve the problem exactly even for non-homeopathic instance sizes of several thousand trajectories in a road network of several million nodes. We also present a parameterized guaranteed-polynomial-time scheme with very good practical performance

Der Einfluss von nor-Binaltorphimin auf die Splanchnikusperfusion im chronisch instrumentierten, wachen Hund

Nor-Binaltorphimin ist ein exogener Antagonist,der selektiv am kappa-Rezeptor angreift.Ziel dieser Studie war es, den Einfluss einer kappa-Rezeptor Blockade auf die Splanchnikusperfusion zu untersuchen.Zehn Foxhounds wurden in einem chirurgischen Eingriff chronisch instrumentiert.Nor-BNI wurde in einer Dosis von 2,5 mg/kgKG i.v. infundiert. 24h, zum Zeitpunkt der maximalen kappa-Rezeptor antagonistischen Wirkung, wurde eine erneute Messung inklusive Blutentnahme durchgeführt.Gezeigt werden konnte das eine selektive kappa-Opioid-Rezeptor Blockade (1.) die Inotropie und das Herzzeitvolumen (HMV) steigert, (2.) die Perfusion vor allem im Intestinum steigert, und (3.) eine Perfusionsumverteilung zugunsten des Splanchnikus stattfindet. Eine intrinsische Aktivität des nor-BNI kann mit großer Wahrscheinlichkeit ausgeschlossen werden