腐蚀保护层中六价铬含量分析

六价铬是一种致癌物质,它在汽车和电子工业中的应用受到欧盟的严格限制。目前,在腐蚀保护层中测定Cr(VI)的分析方法已经颁布实施。本文介绍了可用于上述两个行业的Cr(VI)检测标准──EN 15205和IEC 62321,并讨论了两者的差别。     

Thermal stability of morpholine additive in the steam-water cycle of CANDU-PHW nuclear power plants

The thermal decomposition of morpholine, an additive used in the steam-water cycles of nuclear power plants, was studied using a laboratory high-pressure reactor. The measured decomposition rate constants are 2.67, 8.73 and 21.25 × 10^?7 s^?1 at 260, 280 and 300°C respectively. The kinetics were found to be first-order and the activation energy was 131.9 kJ/mol. Ammonia, ethanolamine, 2-(2-aminoethoxy) ethanol, methylamine, ethylamine, ethylene glycol, and acetic and glycolic acids were identified as the major breakdown products. The decomposition route proposed was validated in the field by tracking these breakdown products in water samples taken at Gentilly 2 power plant.     

Bonding a HTPB liner to modern rocket case materials

Methods for bonding propellants based on HTPB (hydroxyl-terminated polybutadiene) to modern rocket motor case materials have been studied. Thus a typical rocket propellant liner, based on HTPB, was adhesion tested to various polymer materials and to an aluminum alloy. The polymer materials are an epoxy resin and composite materials, based on epoxy-poly(ether sulfone), poly(ether ether ketone), poly(amide imide), and poly(phenylene sulfide). With proper surface treatment, excellent results were obtained at separation tests for all materials with cohesive failure in the liner.     

Synthesis and Evaluation of New Thiodigalactoside‐Based Chemical Probes to Label Galectin‐3

Light up galectin: Photoprobes based on thiodigalactoside were prepared for galectin‐3, a lectin linked to cancer. The probes contained either benzophenone or acetophenone moieties as the photolabel for covalent attachment to the protein. One particular probe labeled galectin‐3 selectively, even in the presence of cell lysate.

     

Expanding RNA Silencing Approaches by U1 Adaptors

Silent partner : In a recent publication, Gunderson and co‐workers described an approach to recruit the abundant U1 snRNP, a splicing subparticle, to the last exon of a pre‐mRNA, in a sequence‐specific manner. This mediates interaction of the U1‐70K protein subunit with poly(A) polymerase, thus blocking polyadenylation and inducing pre‐mRNA degradation. This novel promising strategy expands the repertoire of gene‐silencing concepts.

     

Homology Model Adjustment and Ligand Screening with a Pseudoreceptor of the Human Histamine H4 Receptor

A new pseudoreceptor modeling method (PRPS) was applied to the refinement of a homology model of the human histamine H₄ receptor (H₄R), the prediction of a ligand binding site, and virtual screening. Retrieval of two new H₄R ligands demonstrates the biological relevance of the pseudoreceptor model and provides a means for finding new hits and leads in the early phases of drug discovery.

     

Swiss Industrial Biocatalysis Consortium (SIBC)

Taking up the common challenges in biocatalysis, a group of industrialists decided to react with a bottom-up solution, and created the Swiss Industrial Biocatalysis Consortium (SIBC). The Swiss Industrial Biocatalysis Consortium is a pre-competitive working group to better implement and utilize existing know-how and resources in biocatalysis, and to influence and shape the economic and educational political environment. Recent examples of activities are outlined.     

The Herbivore-Induced Plant Volatile Methyl Salicylate Negatively Affects Attraction of the Parasitoid <Emphasis Type="Italic">Diadegma semiclausum</Emphasis>

The indirect defense mechanisms of plants comprise the production of herbivore-induced plant volatiles that can attract natural enemies of plant attackers. One of the often emitted compounds after herbivory is methyl salicylate (MeSA). Here, we studied the importance of this caterpillar-induced compound in the attraction of the parasitoid wasp Diadegma semiclausum by using a mutant Arabidopsis line. Pieris rapae infested AtBSMT1-KO mutant Arabidopsis plants, compromised in the biosynthesis of MeSA, were more attractive to parasitoids than infested wild-type plants. This suggests that the presence of MeSA has negative effects on parasitoid host-finding behavior when exposed to wild-type production of herbivore-induced Arabidopsis volatiles. Furthermore, in line with this, we recorded a positive correlation between MeSA dose and repellence of D. semiclausum when supplementing the headspace of caterpillar-infested AtBSMT1-KO plants with synthetic MeSA.     

Lytic Polysaccharide Monooxygenase from Talaromyces amestolkiae with an Enigmatic Linker-like Region: The Role of This Enzyme on Cellulose Saccharification

The first lytic polysaccharide monooxygenase (LPMO) detected in the genome of the widespread ascomycete Talaromyces amestolkiae (TamAA9A) has been successfully expressed in Pichia pastoris and characterized. Molecular modeling of TamAA9A showed a structure similar to those from other AA9 LPMOs. Although fungal LPMOs belonging to the genera Penicillium or Talaromyces have not been analyzed in terms of regioselectivity, phylogenetic analyses suggested C1/C4 oxidation which was confirmed by HPAEC. To ascertain the function of a C-terminal linker-like region present in the wild-type sequence of the LPMO, two variants of the wild-type enzyme, one without this sequence and one with an additional C-terminal carbohydrate binding domain (CBM), were designed. The three enzymes (native, without linker and chimeric variant with a CBM) were purified in two chromatographic steps and were thermostable and active in the presence of H₂O₂. The transition midpoint temperature of the wild-type LPMO (Tm = 67.7 °C) and its variant with only the catalytic domain (Tm = 67.6 °C) showed the highest thermostability, whereas the presence of a CBM reduced it (Tm = 57.8 °C) and indicates an adverse effect on the enzyme structure. Besides, the potential of the different T. amestolkiae LPMO variants for their application in the saccharification of cellulosic and lignocellulosic materials was corroborated.     

The corrin moiety of coenzyme B12 is the determinant for switching the btuB riboswitch of E. coli

Riboswitches are regulatory elements in the 5'-untranslated region (5'-UTR) of bacterial mRNAs that bind certain metabolites with high specificity and affinity. The 202 nucleotide (nt)-long btuB riboswitch RNA of E. coli interacts specifically with coenzyme B12 and its derivatives thereby leading to changes in the RNA structure and hence to an altered expression of the downstream btuB gene. We report the investigations of the rearrangement of the three-dimensional structure of the btuB riboswitch upon binding to four different B12 derivatives: coenzyme B12, vitamin B12, adenosyl factor A and adenosyl-cobinamide. In-line probing experiments have shown that the corrin ring plays the crucial role in switching the three-dimensional riboswitch structure. Instead, the apical ligands influence only the binding affinity of the B12 derivative to the btuB riboswitch.