NMR measurements of gaseous sulfur hexafluoride (SF6) to probe the cross-linking of EPDM rubber.

The effects of embedding gaseous SF6 into EPDM rubber were investigated using NMR methods. It was found that observed sorption and desorption processes follow the behavior of the dual mode sorption model. A strong correlation was found between EPDM cross-linking and transversal relaxation time of embedded SF6. EPDM samples with different cross-link densities, preliminarily determined by 1H transversal relaxation using the Gotlib model and Litvinov's method, were investigated using embedded SF6. The sensitivity of the 19F transversal relaxation rate of SF6 to the EPDM cross-link density variation was found to be at least 10 times higher than for 1H in the polymer chain. First experiments on probing the swelling effects in EPDM due to its contact with polar liquids have been performed.

Application of single point imaging (SPI) to solid state materials.

Single Point Imaging (SPI) is a 3D phase encoding MRI method proposed by S. Emid and J.H.N. Creyghton [1] to study solid state materials with a very short T(2) value (>50 micros). In this short communication experimental results of SPI applications to various industrial important solid materials, such as porosity of chocolate samples, connectivity of micro-channels in earth samples, etc. are reported.

Volume-selective multi-pulse spin-echo spectroscopy and selective suppression of spectral lines.

A method is described allowing the recording of in vivo NMR spectra in sharply bound volume elements preselected on the basis of slice images. Experiments with phantom samples, as well as with a test person in a whole-body instrument, have been carried out to demonstrate the applicability of the technique. In the case of proton spectroscopy, suppression of the water and/or or of the lipid line is often desirable. A corresponding pulse sequence has been implemented and successfully tested with a phantom sample.

[MR-tomography and -spectroscopy of skeletal muscles using high magnetic field strengths]. / MR-Tomographie und -Spektroskopie der Skelettmuskulatur bei hohen Magnetfeldstärken.

Intact as well as neuromuscular affected skeletal muscles can be precisely analysed by MR tomography with high magnetic field strengths. The substitution of muscle by adipose tissue under atrophic conditions is seen most clearly in fat images, while the morphology of small structures is predominantly shown by water images. The aim of in-vivo spectroscopy is an identification and quantification of metabolites. A relative increase in the amount of adipose tissue within atrophic muscles was confirmed by the 1-H spectrum. As concluded from 13-C and 31-P spectra there was neither a change in adipose tissue composition nor a modification of energy metabolism.