A Wind Tunnel Setup for Fluid-Structure Interaction Measurements Using Optical Methods.

The design of rotor blades is based on information about aerodynamic phenomena. An important one is fluid-structure interaction (FSI) which describes the interaction between a flexible object (rotor blade) and the surrounding fluid (wind). However, the acquisition of FSI is complex, and only a few practical concepts are known. This paper presents a measurement setup to acquire real information about the FSI of rotating wind turbines in wind tunnel experiments. The setup consists of two optical measurement systems to simultaneously record fluid (PIV system) and deformation (photogrammetry system) information in one global coordinate system. Techniques to combine both systems temporally and spatially are discussed in this paper. Furthermore, the successful application is shown by several experiments. Here, different wind conditions are applied. The experiments show that the new setup can acquire high-quality area-based information about fluid and deformation.

Transglycosylations employing recombinant α- and ß-galactosidases and novel donor substrates.

Recombinant α- and ß-galactosidases could be prepared in larger amounts for chemoenzymatic syntheses of glycosylated oligosaccharides relevant in nutrition approaches. α-Galactosidase RafA from Escherichia coli, another thermophilic α-galactosidase AgaB from Geobacillus stearothermophilus KVE39, and also a thermophilic ß-galactosidase BglT from Thermus thermophilus TH 125 could be employed in α- and in ß-glycosylations, respectively. With model structures as well as sucrose, isomaltitol, and isomaltulose the stereo- and regiospecificities were studied. Further, a number of modified donor structures with structural variation and different leaving groups were synthesized, employed, and compared to classical donors for these transglycosylations.

Some findings in transgalactosylations employing modified donor substrates.

The scope of transgalactosylation with ß-galactosidase (bovine testis) was studied employing a series of modified donor substrates based on p-nitrophenyl ß-D-galactopyranoside and as uniform acceptor allyl 2-N-acetamido-2-deoxy-α-D-galactopyranoside. Structurally diverse donor molecules were recognized by the enzyme and led to novel disaccharide components, yet an excessive structural distortion was not accepted.

Solid-phase random glycosylation.

Two different approaches were employed to study solid phase random glycosylations to obtain oligosaccharide libraries. In approach I, Wang resin esters were attached to the acceptors structures. Following their glycosylation and resin cleavage, the peracetylated components of the oligosaccharide libraries were characterized. In approach II, polymer-linked donor components could be employed and processed correspondingly. Approach I proved to be superior regarding yield and versatility of products and also allowed the formation of higher oligomers.

Comparative solution and solid-phase glycosylations toward a disaccharide library.

A comparative study on solution-phase and solid-phase oligosaccharide synthesis was performed. A 16-member library containing all regioisomers of Glc-Glc, Glc-Gal, Gal-Glc, and Gal-Gal disaccharides was synthesized both in solution and on solid phase. The various reaction conditions for different approaches and corresponding yields are analyzed and discussed.

Synthesis and evaluation of glycosyl donors with novel leaving groups for transglycosylations employing beta-galactosidase from bovine testes.

Novel aryl beta-d-galactopyranosides were synthesized employing phase-transfer catalysis, and assayed as potential galactose donors in the presence of beta-galactosidase from bovine testes using pNP-Gal as a reference. The aglycones were represented mainly by nitrophenols containing halogens, hydroxymethyl, aldehyde, carboxyl, ester or amino functions. An unusual intermolecular acetyl migration onto the benzylic alcohol group was observed during galactosylation of hydroxymethylnitrophenols. Pyridyl glycosides were obtained by reaction with the corresponding silver pyridinolates. Glycosides of halo-, hydroxymethyl- or methoxycarbonyl-nitrophenols as leaving groups gave virtually the same yields of transglycosylation products. A minor increase was achieved with nitrosalicylaldehyde as leaving group, whereas carboxy or amino derivatives gave very low or no yield of the transglycosylation product. Commercially available donors such as resorufinyl and 4-methylumbelliferyl beta-d-galactopyranosides exhibited a lower transglycosylation potential than these novel pNP-Gal derivatives.

Enzyme-catalysed synthesis of galactosylated 1D- and 1L-chiro-inositol, 1D-pinitol, myo-inositol and selected derivatives using the beta-galactosidase from the thermophile Thermoanaerobacter sp. strain TP6-B1.

The products from the enzymatic beta-D-galactopyranosylation of 1D-chiro-inositol, 1D-pinitol, 1D-3-O-allyl-4-O-methyl-chiro-inositol, 1D-3,4-di-O-methyl-chiro-inositol, 1L-chiro-inositol and myo-inositol in combined yields ranging from 46% to 64% have been obtained using the beta-galactosidase isolated from an anaerobic extreme thermophile, Thermoanaerobacter sp. strain TP6-B1 and p-nitrophenyl beta-D-galactopyranoside as the donor. Analysis of the products from these reactions reveals information about the acceptor preferences of the enzyme.

Novel O-glycosyl amino acid mimetics as building blocks for O-glycopeptides act as inhibitors of galactosidases.

As potential lead structures for a new class of glycosidase inhibitors the novel O-glycosyl amino acid mimetics 3'-O-[2,6-anhydro-D-glycero-L-gluco-heptitol-1-yl]-L-serine 3 and-L-threonine 4 were synthesized, employing regio- and stereoselective aziridine ring opening methodology. They proved to be stable in the presence of glycosidases and showed competitive inhibition of alpha-galactosidase from Aspergillus niger.