Abstract: A highly specific surface for biological reactions, which includes a support with at least one essentially compact layer of an organic compound. On the outside of the organic compound layer is an exposed group containing an ethylenic double bond, which has affinity for a molecule with biological activity under certain reaction conditions. The other elements of the organic compound layer are essentially inaccessible to the molecule with biological activity under the reaction conditions.

Abstract: Macromolecules such as nucleic acids, proteins, lipids or polysaccharides are aligned on a support surface by passing the macromolecules through a meniscus of a solvent containing the macromolecules. The meniscus may be that of a solvent between two surfaces at an interface of the solvent with air. One end of a macromolecule is attached to one surface which may be a glass surface and another end is free. The meniscus is moved relative to the surface to which the end is attached such as by evaporating the solvent or by moving the surface. As the macromolecule passes through the meniscus, the macromolecule aligns on the surface perpendicular to the meniscus. This method may be used in assaying, measuring intramolecular distance and/or separating of macromolecules.

Abstract: The present invention relates especially to a highly specific surface for biological reactions, characterized in that it contains a support having at the surface at least one essentially compact layer of an organic compound having, outside the layer, an exposed group containing an ethylenic double bond having affinity for one type of molecule with biological activity under certain reaction conditions, the other elements of the layer being essentially inaccessible for the said molecules under the said reaction conditions.

Abstract: Macromolecules such as nucleic acid strands are aligned, adhered and stretched on a support surface by passing the strands through a meniscus of a solvent containing the strands. The meniscus may be that of a solvent between two surfaces at an interface of the solvent with air. One end of a nucleic acid strand is attached to one surface which may be a glass surface and another end is free. The meniscus is moved relative to the surface to which the end is attached such as by evaporating the solvent or by moving the surface. As the nucleic acid strand passes through the meniscus, the strand elongates and aligns perpendicular to the meniscus on the surface. This method may be used in assaying, measuring intramolecular distance of and/or separating macromolecules.

Abstract: The present invention relates especially to a highly specific surface for biological reactions, characterized in that it contains a support having at the surface at least one essentially compact layer of an organic compound having, outside the layer, an exposed group containing an ethylenic double bond having affinity for one type of molecule with biological activity under certain reaction conditions, the other elements of the layer being essentially inaccessible for the said molecules under the said reaction conditions.

Abstract: In a pipe containing a fluid wherein particles circulate, at least one detector is attached. The detector includes a cavity in fluid communication with the pipe by a vent whose section, at least at an opening for fluid communication with a pipe is of the same dimensions as that of the circulating particles. A periodic exciter such as a source of acoustical waves or a generator of the periodic motion piston type suitable for inducing alternate pressure variations in the fluid in the cavity is coupled with the cavity. The excitation frequency can be selected in keeping with a resonance frequency of the cavity. Signals representative of the pressure variations of the excited fluid, resulting from flowing of the particles past the opening of each vent are measured. Processing of the signals allows the velocity of the particles to be determined. Other parameters of the particles can be determined by means of two distinct detectors coupled with the pipe.