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Abstract: Colorectal cancer is one of the most frequent and most lethal forms of cancer in the western world. The aim of this study is to characterize by 1H high resolution magic angle spinning NMR spectroscopy (HRMAS) the metabolic fingerprint of both tumoral and healthy tissue samples obtained from a cohort of patients affected by primary colorectal adenocarcinoma. By analyzing HRMAS data using multivariate statistical analysis (PLS-DA), the two types of tissues could be discriminated with a high level of confidence. The identification of the metabolites at the origin of this discrimination revealed that adenocarcinomas are richer in taurine, glutamate, aspartate, and lactate whereas healthy tissues contain a higher amount of myo-inositol and β-glucose. The statistical model resulting from the PLS-DA analysis was subsequently used to perform a blind test on tumoral and healthy colon biopsies. The results of the classification showed that the HRMAS analysis has very high sensitivity and specificity.

Accurate chemical shifts are now accessible with high field NMR spectrometers. After the recall of the basic formulae, methods are proposed to measure chemical shifts with a high precision. Using two coaxial rotors at the magic angle, the necessary parameters used for correction are measured. The influence of different factors on the precision of the NMR measurements is discussed. Some proposals are given for MAS experiments used with solid‐state samples. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 184–193, 2007.

In this work an original process for buried folded silicon microchannel fabrication is reported. Electrochemical micromachining is exploited to etch high aspect ratio meander-shaped trenches into a silicon substrate. Thermal oxidation is then employed to seal the top of etched trenches and obtain buried microchannels at the bottom. The process is straightforward and allows the integration of buried folded channels into silicon substrates with a high density. Experimental results are reported and advantages and drawbacks of the proposed process are discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The solid-phase synthesis of 2,5-diketopiperazines containing the trans-4-hydroxy-l-proline amino acid residue (Hyp) was performed on Ellman polystyrene, polyoxyethylene-polyoxypropylene (POEPOP), polystyrene-polyoxyethylene NovaSyn, and Wang resins, respectively. The reaction pathway allowed the introduction of different functional groups around the bicyclic scaffold in a combinatorial approach, and it generated mixtures of isomers. A detailed characterization of the single reaction steps by high resolution magic angle spinning (HRMAS) NMR spectroscopy was performed. The NMR spectral resolution of the resin-bound intermediates and final products was greatly influenced by the polymer matrix. The POEPOP resin permitted to obtain HRMAS NMR spectra with a resolution comparable with that of the spectra of the molecules in solution. Moreover, configurational and conformational isomers formed during the solid-phase reaction steps could be detected and easily assigned. Therefore, the combination of the HRMAS NMR technique with the use of nonaromatic resins may become an extremely powerful tool in solid-phase organic synthesis. This approach will allow the monitoring of multistep reactions and the conception of on-bead structural studies either on small molecules or on natural and/or synthetic oligomers.

The effects of electromigration in metal thin films is studied by means of atomistic Monte Carlo simulations. The simulator is based on a model of atom diffusion particularly suited to deal with polycrystalline three-dimensional films. Interatomic interactions are estimated by means of a simplified Morse potential while the driving force exerted by the charge carrier flux is represented as a perturbation on the diffusion activation barrier. The local current density is calculated using an equivalent resistor network. The results of simulated stress applied to various samples including a triple point are presented demonstrating the possibility of reproducing the initial stage of void formation with an atomistic model.

Solid-state nuclear magnetic resonance (NMR) techniques were used to characterize cyclomaltoheptaose (β-cyclodextrin, β-CD) polymers. These insoluble materials have been investigated by cross-polarization magic angle spinning with dipolar decoupling (CP/MAS), magic angle spinning without dipolar decoupling (MAS), and high-resolution magic angle spinning with gradients (HRMAS). These NMR spectra allow the assignment of the principal ¹H and ¹³C signals. The presence of two distinct components (cross-linked β-CD and polymerized epichlorohydrin) in the materials was clearly demonstrated. These polymers were used as sorbents and the resulting NMR spectra are presented and discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1288–1295, 2000