Polarization confocal microscopy and congo red fluorescence: a simple and rapid method to determine the mean cellulose fibril orientation in plants.

The mean or net preferential orientation of cellulose fibrils in plant cell walls is detected with polarization confocal laser scanning microscopy using the fluorescence dichroism of Congo Red. Single cells, arrays of cells in a tissue, or the epidermis of whole organs can be assayed in vivo. Aerial parts require an extra pectinase treatment because of the cuticle, which is impermeable to aqueous solutions.

The selenium status of Belgian population groups : II. Newborns, children, and the aged.

The selenium state of 40 elderly Belgian people, residing in geriatric homes, has been evaluated. Data are presented on the selenium (Se) contents of their blood, plasma, and erythrocytes. The activity of glutathione peroxidase (GSH-Px) has been assayed.

The determination of selenium by atomic-absorption spectrometry: A review.

A comprehensive review is given of the determination of selenium by the various atomic-absorption spectrometry methods that have been developed, covering the use of various flame and electrothermal ionization methods, hydride techniques, preconcentration and separation, and giving an appraisal of the results.

Optimization of the determination of selenium by atomic-absorption spectrometry: Comparison of two hydride generation systems.

Two commercially available systems for the determination of selenium by hydride-generation and atomic-absorption spectrometry were compared. Chemical and physical parameters were optimized both for an electrothermally heated closed atom-cell method and a flame-heated open-cell technique. Both systems were evaluated with respect to performance and applicability to determination of traces of selenium.

Comparison of experimental and calculated relative sensitivity coefficients for spark-source mass-spectrometry of metals.

Sensitivity calibration has been performed for the spark-source mass-spectrometric analysis of iron, copper and aluminium matrices, with standard reference materials. The experimental relative sensitivity coefficients, corrected for discrimination effects in the mass spectrometer, are compared with values obtained with various empirical approaches to calculate relative sensitivity coefficients for an r.f.