Discovery of a Neutral 40-Pd-Oxo Molecular Disk, [PdO(OH){(CH)AsO}]: Synthesis, Structural Characterization, and Catalytic Studies.

We report on the synthesis and structural characterization of a giant, discrete, and neutral molecular disk, [PdO(OH){(CH)AsO}] (), comprising a 40-palladium-oxo core that is capped by 16 dimethylarsinate moieties, resulting in a palladium-oxo cluster (POC) with a diameter of ∼2 nm. , which is the largest known neutral Pd-based oxo cluster, can be isolated either as a discrete species or constituting a 3D H-bonded organic-inorganic framework (HOIF) with a 12-tungstate Keggin ion, [SiWO] or [GeWO]. H and C NMR as well as H-DOSY NMR studies indicate that is stable in aqueous solution, which is also confirmed by ESI-MS studies.

Discrete Polyoxopalladates as Molecular Precursors for Supported Palladium Metal Nanoparticles as Hydrogenation Catalysts.

We have used discrete polyoxopalladates(II) (POPs) of the MPdX nanocube- and PdX nanostar-types (M = central metal ion, X = capping group) as molecular precursors (diameter ca. 1 nm) for the formation of supported (SBA-15) metallic nanoparticles. These materials proved to be highly active in the hydrogenation of o-xylene.

Organo-ruthenium supported heteropolytungstates: synthesis, structure, electrochemistry, and oxidation catalysis.

The reaction of [Ru(arene)Cl(2)](2) (arene = benzene, p-cymene) with [X(2)W(22)O(74)(OH)(2)](12-) (X = Sb(III), Bi(III)) in buffer medium resulted in four organo-ruthenium supported heteropolytungstates, [Sb(2)W(20)O(70)(RuC(6)H(6))(2)](10-) (1), [Bi(2)W(20)O(70)(RuC(6)H(6))(2)](10-) (2), [Sb(2)W(20)O(70)(RuC(10)H(14))(2)](10-) (3), and [Bi(2)W(20)O(70)(RuC(10)H(14))(2)](10-) (4), which have been characterized in solution by multinuclear ((183)W, (13)C, (1)H) NMR, UV-vis spectroscopy, electrochemistry, and in the solid state by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and elemental analysis. Polyanions 1, 2, and 4 crystallize in the triclinic system, space group P1 with the following unit cell parameters: K(5)Na(5)[Sb(2)W(20)O(70)(RuC(6)H(6))(2)] x 22 H(2)O (KNa-1), a = 12.1625(2) A, b = 13.

Heterogeneous wheel-shaped Cu20-polyoxotungstate [Cu20Cl(OH)24(H2O)12(P8W48O184)]25- catalyst for solvent-free aerobic oxidation of n-hexadecane.

The selective oxidation of alkanes as a green process remains a challenging task because partial oxidation is easier to achieve with sacrificial oxidants, such as hydrogen peroxide, alkyl hydroperoxides or iodosylbenzene, than with molecular oxygen or air. Here, we report on a heterogeneous catalyst for n-hexadecane oxidation comprised of the wheel shaped Cu20-polyoxotungstate [Cu20Cl(OH)24(H2O)12(P8W48O184)]25- anchored on 3-aminopropyltriethoxysilane (apts)-modified SBA-15. The catalysts were characterized by powder X-ray diffraction (XRD), N2-adsorption measurements and Fourier transform infrared reflectance (FT-IR) spectroscopy.

Solvent-free aerobic oxidation of n-alkane by iron(III)-substituted polyoxotungstates immobilized on SBA-15.

The tetrairon(III)-substituted polytungstates [Fe(4)(H(2)O)(10)(beta-XW(9)O(33))(2)](n-) (n = 6, X = As(III), Sb(III); n = 4, X = Se(IV), Te(IV)) were immobilized on (3-aminopropyl)triethoxysilane-modified SBA-15 and showed an excellent catalytic performance for solvent-free aerobic oxidation of long-chain n-alkanes using air as the oxidant under ambient conditions through a classical free-radical chain autoxidation mechanism.

Protease activity in gut of Daphnia magna: evidence for trypsin and chymotrypsin enzymes.

Two major protease activities were present in gut homogenates of the cladoceran crustacean Daphnia magna: (i) a trypsin activity that hydrolysed the synthetic substrate N-benzoyl-dl-arginine p-nitroanilide and was strongly inhibited by N-p-tosyl-lysine chloroketone (TLCK) and 4-(amidinophenyl)methanesulfonyl fluoride (APMSF) and not inhibited by chymostatin; and (ii) a chymotrypsin activity that hydrolysed synthetic chymotrypsin substrates containing more than one amino acid, did not hydrolyse N-benzoyl-l-tyrosine p-nitroanilide, and was strongly inhibited by chymostatin and not by TLCK and APMSF. Both activities had alkaline pH optima (pH 7-10), but were shown to be due to distinct types of proteases. These two enzyme activities accounted for 75-83% of the proteolytic activity of gut contents.

In vivo evaluation of an intravascular receiver coil for MRI at 1.0 Tesla.

Background: Evaluation of the applicability of intravascular radiofrequency receiver coils by means of a pig in-vivo-experiment for the detection of vessel wall structures at 1.0 Tesla.

Materials And Methods: The intravascular receiver coil was constructed according to a well evaluated single-loop-design, which was mounted onto a balloon catheter for angioplasty.

A comparison of four immunometric assays for myeloperoxidase using luminescent and colorimetric signal detection.

This communication presents four different assay systems for the determination of myeloperoxidase in body fluids. One is based on conventional chemiluminescence, two on luminescence-amplified enzyme measurement using either spiroadamantane-1,2-dioxetanes with alkaline phosphatase or luminol/peroxidase/4-iodophenol coupled with a peroxidase label. The assays covered the range 0-600 micrograms/l peroxidase.

[The behavior of glucose tolerance, serum insulin and C-peptide in acute viral hepatitis].

On 35 patients with acute hepatitis had been carried out intravenous glucose-tolerance-tests (0,5 g glucose/kg). The assimilation coefficient of glucose and the level of insulin were determined during the acute phase of illness and the recovery phase. In 8 cases additionally C-peptide was determined to interpret the regulation of insulin-secretion and hepatic reduction.