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The Solar-Institute Jülich (SIJ) has initiated the construction of the first and only German solar tower power plant and is now involved in the accompanying research. The power plant for experimental and demonstration purposes in the town of Jülich started supplying electric energy in the beginning of 2008. The central receiver plant features as central innovation an open volumetric receiver, consisting of porous ceramic elements that simultaneously absorb the concentrated sunlight and transfer the heat to ambient air passing through the pores so that an average temperature of 680°C is reached. The subsequent steam cycle generates up to 1.5 MWe. A main field of research at the SIJ is the optimization of the absorber structures. To analyze the capability of new absorber specimens a special test facility was developed and set up in the laboratory. A high-performance near-infrared radiator offers for single test samples a variable and repeatable beam with a power of up to 320 kW/m² peak. The temperatures achieved on the absorber surface can reach more than 1000°C. To suck ambient air through the open absorber - like on the tower - it is mounted on a special blower system. An overview about the test facility and some recent results will be presented.

The Solar-Institute Jülich (SIJ) has initiated the construction of the first and only German solar tower power plant and is now involved in the accompanying research. The power plant for experimental and demonstration purposes in the town of Jülich started supplying electric energy in the beginning of 2008. The central receiver plant features as central innovation an open volumetric receiver, consisting of porous ceramic elements that simultaneously absorb the concentrated sunlight and transfer the heat to ambient air passing through the pores so that an average temperature of 680°C is reached. The subsequent steam cycle generates up to 1.5 MWe. A main field of research at the SIJ is the optimization of the absorber structures. To analyze the capability of new absorber specimens a special test facility was developed and set up in the laboratory. A high-performance near-infrared radiator offers for single test samples a variable and repeatable beam with a power of up to 320 kW/m² peak. The temperatures achieved on the absorber surface can reach more than 1000°C. To suck ambient air through the open absorber - like on the tower - it is mounted on a special blower system. An overview about the test facility and some recent results will be presented.

Carbohydrate recognition by monocot mannose-binding lectins was studied viathe crystal structure determination of daffodil (Narcissus pseudonarcissus) lectin. The lectin was extracted from daffodil bulbs, and crystallised in the presence of α-1,3 mannobiose. Molecular replacement methods were used to solve the structure using the partially refined model of Hippeastrum hybridagglutinin as a search model. The structure was refined at 2.0 Å resolution to a final R-factor of 18.7 %, and Rfreeof 26.7 %.

The six clones pTB112, pTB324, pTBs12, pCd122, pCd14 and pCdl3 cover thetox locus ofClostridium difficile VPI 10463. This region of 19 kb of chromosomal DNA contains four open reading frames including the completetoxB andtoxA genes. The two toxins show 63% amino acid (aa) homology, a relatedness that had been predicted by the cross-reactivity of some monoclonal antibodies (mAb) but that is in contrast to the toxin specificity of polyclonal antisera. A special feature of ToxA and ToxB is their repetitive C-termini. We define herein 19 individual CROPS (combinedrepetitiveoligopeptides of 20–50 as length) in the ToxB C-terminus, which are separable into five homologous groups. Comparison of the as sequences of the N-terminal two-thirds of ToxA and ToxB revealed three marked structures, a cluster of 172 hydrophobic, highly conserved as in the centre of both toxins, a sequence of 120 residues with an accumulation of highly conserved arginine, cysteine, histidine, methionine, and tryptophan residues, and a stretch of 248 less conserved aa. The probable function of these domains is discussed. Structural and functional homologies of ToxA and ToxB indicate that both genes have a common ancestor and may have evolved by gene duplication, with subsequent recombination and mutation, as has been reported for streptococcal glucosyltransferases (Gtf).

We have investigated the ability of a recombinant protein (REP231), derived from Clostridium difficiletoxin A C‐terminal domain, to protect against toxin A (TcdA) intoxication in vitro and in vivo. REP231 was cloned, expressed and purified by thyroglobulin affinity chromatography, and demonstrated identical binding properties to TcdA. Immunofluorescence experiments and in vitro cytotoxicity assays using mouse teratocarcinoma cells F9 showed that specific binding of TcdA to F9 cells through its C‐terminal domain is essential for producing cytotoxic effects. TcdA binding and cytotoxicity was inhibited by REP231 and a monoclonal antibody directed against the C‐terminal domain. Toxin B did not bind to F9 cells and was consequently inactive in cytotoxicity assays. Inhibition studies with lectins and a Lex‐specific antibody supported earlier findings that a terminal galactose is part of the bound saccharide but excluded Lexas a receptor for TcdA. Mice immunised with REP231 were protected against a threefold lethal dose of TcdA. Thus, REP231 appeared to be a suitable candidate to develop an alternative therapeutic agent, which is able to neutralise carbohydrate‐mediated TcdA binding and might act as a vaccine.

We have investigated the ability of a recombinant protein (REP231), derived from Clostridium difficile toxin A C-terminal domain, to protect against toxin A (TcdA) intoxication in vitro and in vivo. REP231 was cloned, expressed and purified by thyroglobulin affinity chromatography, and demonstrated identical binding properties to TcdA. Immunofluorescence experiments and in vitro cytotoxicity assays using mouse teratocarcinoma cells F9 showed that specific binding of TcdA to F9 cells through its C-terminal domain is essential for producing cytotoxic effects. TcdA binding and cytotoxicity was inhibited by REP231 and a monoclonal antibody directed against the C-terminal domain. Toxin B did not bind to F9 cells and was consequently inactive in cytotoxicity assays. Inhibition studies with lectins and a Lex-specific antibody supported earlier findings that a terminal galactose is part of the bound saccharide but excluded Lex as a receptor for TcdA. Mice immunised with REP231 were protected against a threefold lethal dose of TcdA. Thus, REP231 appeared to be a suitable candidate to develop an alternative therapeutic agent, which is able to neutralise carbohydrate-mediated TcdA binding and might act as a vaccine.