Selective Manipulation of Well-Defined Trinuclear Pd(II)-Complexes.

Several strategies are available to design well-defined multimetallic molecular entities bearing functional ligands. Substoichiometric exchange reactions in the coordination sphere of pre-existing multinuclear precursors are relatively underexploited in this context. Palladium(II) acetate is not a mononuclear compound in the solid state but rather exists as a trimer, i. e. [Pd3(OAc)6]. Although this material is ubiquitously used to synthesize mononuclear Pd species, it may principally also lend itself to selective exchange of some of the edge-sharing acetate units in its triangular motif, whilst keeping the overall multinuclear architecture intact. Strikingly, little is known about the controlled manipulation and substoichiometric substitution chemistry of this well-defined conglomerate. We herein conclusively demonstrate that, for the first time, the targeted exchange of two or four acetate units from the Pd3(acetate)6 platform is possible, thereby installing either one or two new tridentate ligands onto this trinuclear architecture. Follow-up exchange and substitution chemistry is available without disrupting the multimetallic nature of the core structure. New complexes 2-7 are all conclusively characterized using multinuclear NMR spectroscopy, UV-vis and IR spectroscopy as well as X-ray diffraction analysis.

Bioavailability of amoxicillin and clavulanic acid from extended release tablets depends on intragastric tablet deposition and gastric emptying.

The rate and extent of amoxicillin and clavulanic acid absorption from pharmacokinetically enhanced extended release (ER) tablets is strongly influenced by the intake conditions. In order to investigate the cause of the food effects, a pharmacokinetic study with simultaneous imaging of the in vivo behaviour of the ER tablets by magnetic marker monitoring (MMM) was performed. Under fasting conditions the amoxicillin AUC (1854+/-280microg min ml(-1)) was significantly lower than after intake at the beginning of the breakfast (2452+/-354microg min ml(-1)) or after the breakfast (2605+/-446microg min ml(-1)). In contrast, clavulanic acid AUC was well comparable after tablet intake under fasting conditions and intake at the beginning of a breakfast (191+/-46 and 189+/-44microg min ml(-1), respectively) but significantly lower following a breakfast (126+/-71microg min ml(-1)). The localization data showed that the reduced bioavailability of amoxicillin under fasting conditions is due to early gastric emptying in combination with poor absorption from deeper parts of the small intestine. Prolonged gastric residence of clavulanic acid caused by intragastric tablet deposition in the proximal stomach was identified as the reason for the decreased bioavailability of clavulanic acid after tablet intake following the meal.

Chirality as a tool for function in porous organic cages.

The control of solid state assembly for porous organic cages is more challenging than for extended frameworks, such as metal-organic frameworks. Chiral recognition is one approach to achieving this control. Here we investigate chiral analogues of cages that were previously studied as racemates. We show that chiral cages can be produced directly from chiral precursors or by separating racemic cages by co-crystallisation with a second chiral cage, opening up a route to producing chiral cages from achiral precursors. These chiral cages can be cocrystallized in a modular, 'isoreticular' fashion, thus modifying porosity, although some chiral pairings require a specific solvent to direct the crystal into the desired packing mode. Certain cages are shown to interconvert chirality in solution, and the steric factors governing this behavior are explored both by experiment and by computational modelling.

Mimicking oxide surfaces: different types of defects and ligand coordination at well defined positions of a molybdenum oxide based nanocluster.

The mixed valence cluster anion of the compound (NH4)32[MoVI110MoV28O416H6(H2O)58(CH3CO2)6].xH2O 1 (x approximately 250), synthesized under one-pot conditions, contains well-defined different types of defects--missing groups compared to the complete parent (Mo154) type cluster with full D7d symmetry--and acetate ligand coordination; this proves that the giant-wheel type anion can be considered as an object with a variety of nanoscale structural features ("nanostructured landscape") allowing reactions at a variety of well defined centers.

"Open and Shut" for Guests in Molybdenum-Oxide-Based Giant Spheres, Baskets, and Rings Containing the Pentagon as a Common Structural Element.

A novel exchange between ligands and/or guest molecules can be accomplished in giant molecular spheres (an example is shown in the picture) which are in equilibrium with the corresponding giant baskets in solution.

Archimedean Synthesis and Magic Numbers: "Sizing" Giant Molybdenum-Oxide-Based Molecular Spheres of the Keplerate Type.

Pythagorean harmony can be found in the spherical polyoxometalate clusters described here (see illustration for an example of a structure), since there are interesting relationships between the so-called magic numbers (12, 32, 42, 72, 132) relevant for spherical viruses and the number of the building blocks in the cluster. The size of these Keplerate clusters can be tailored by varying the type of connections between the pentagons by means of different spacers.

[Anorectal manometry]. / Empfehlungen zur Anorektalen Manometrie im Erwachsenenalter.

This document contains the guidelines of the German Societies of Neurogastroenterology and Motility, Gastroenterology (committee for proctology), Abdominal Surgery (coloproctology working group), and Coloproctology for anorectal manometry in adults. Recommendations are given about technical notes, study preparation (equipment; patient), technique for performing manometry and data analysis, reproducibility, and indications. Minimum standards for anorectal manometry are measurement of resting and squeeze pressure, testing of rectoanal inhibitory reflex, determination of rectal sensation (first perception and urge), and calculation of rectal compliance. Anorectal manometry is indicated in patients with fecal incontinence and constipation in the context of a structured programme.

[Drug therapy for irritable bowel syndrome. What works, what doesn't work and for whom?]. / Arzneimitteltherapie des Reizdarmsyndroms. Was funktioniert, was nicht--und bei wem?

The therapy of patients with irritable bowel syndrome (IBS) is often challenging, especially if a broad spectrum of symptoms is present and trigger factors, such as the influence of diet or stress, are lacking. Current pathogenetic concepts propose central or peripheral alterations that cause disturbed gastrointestinal function (motility, visceral sensitivity) and subsequent symptoms. These alterations are possibly related to psychological (stress, depression, anxiety) and biological (post-infectious residuals, micro-inflammation) influences. Since no universally effective medical treatment is available to treat the causes of the disease, standard medical therapy is symptom directed (especially for pain, constipation and diarrhoea). In addition to well established drugs (like spasmolytics, opioids and laxatives), newly developed compounds including those with other primarily indications (e.g. antidepressants) are available for highly differentiated individualized therapies. New medical approaches which are currently undergoing evaluation, promise further progress in the treatment of IBS.