Discrimination of single mutations in cancer-related gene fragments with a surface acoustic wave sensor

Here, we report on using a surface acoustic wave sensor for the highly sensitive and accurate detection of individual point mutations in cancer-related gene DNA fragments from single injections. Our sensor measures both the mass and viscosity signals and, thus, allows discriminating between mass effects resulting from hybridization of short DNA strands and viscosity effects due to increasing amounts of DNA deposited on the sensor. Single nucleotide exchanges or deletions are distinguished reliably and with exceeding simplicity from the wild-type sequences, on the basis of differences in their dissociation or association rates starting at low nanomolar concentrations. Mutant oligonucleotides were identified immediately from viewing the recorded signal and without further processing of the data. Multiple repeated binding cycles were possible over days without affecting sensitivity. To achieve signal amplification, our new bioassay can also apply multiple hybridization steps based on sandwich hybridizations. Kinetic evaluations gave insight into the physicochemical properties of the fragments used that explain the differences in their binding processes.     

Fixierung von β-Cyclodextrinderivaten auf Polyesterfasermaterial

Fixation of β-Cyclodextrinderivatives on Polyester Fibres . Syntheses of derivatives of β-cyclodextrin are described which aimed at a partial substitution of OH-groups by hydrophobic moieties. According to such substitution it can be envisaged that those derivatives are applicable to polyester fabric treatment by conventional dispersion dyeing methods. By applying such textile finishing agents it can be expected to impart hydrophilic properties to the fabric due to unsubstituted OH-groups of the cyclodextrin but still remaining complexation ability due to the cyclodextrin inner torus. The success of anchoring of the derivatives onto polyester and methods for evidence of cyclodextrin derivatives on the polyester surface (iodine incorporation, fluorescence activity of dyestuffs included, FT-IR-spectroscopy) are given.     

Tap Reactor for Temporally and Spatially Resolved Analysis of the CO2 Methanation Reaction

Chemical energy carriers produced according to power-to-X concepts will play a crucial role in the future energy system. Here, CO₂ methanation is described as one promising route. However, transient operating conditions and the resulting effects on catalyst stability are to be considered. In this contribution, a tap reactor for spatially and temporally resolved analysis of the methanation reaction is presented. The Ni catalyst investigated was implemented as coating. Reaction data as a function of time and reactor coordinate under various operating conditions are presented and discussed. A comparison with simulation data validates the presented tap reactor concept.     

The Cutting of Steel Tubes by Explosives Techniques. Cutting performance and effects on environment

In the light of special applications, trials were carried out on the separation of steel tubes using commercially obtainable explosive cutting charges in an annular configuration in order to find out their cutting performance and the effects on the environment incurred during separation. Tubes made of St37 steel having a diameter of 220 mm and a wall thickness of 10 mm as well as tubes consisting of hightensile 15 Mo 3 steel with a diameter of 273 mm and a wall thickness of 12.5 mm were used for this purpose. It was possible to cut the tubes accurately and neatly with the charges used. However, the projectiles formed during the detonation process are not compact, for which reason the cutting performance of the commercial charges used is not optimal. There is here a considerable potential for improvement. Measurements of the environmental effects conducted during the trials (fragmentation, blast wave, projectile impact on tube line) show that the incidental effects of explosive tube cutting are controllable.