Abstract: The invention relates to a method of measuring antigens or antibodies in biological fluids in appropriately designed reaction cells in an automated analytical apparatus. The method includes the steps of contacting, in the reaction cell, the biological fluid with antibodies specific for a desired analyte antigen, which antibodies are coated on magnetic particulate carrier, under conditions such that binding of the antibody to the desired analyte antigen occurs, and detecting the presence or absence of an immunocomplex formed between the antibody and the desired analyte antigen. The automated analytical apparatus includes a closed circuit transfer path having means for transferring cells around the entire transfer path, and a thermostating period for each analysis to be performed with the automated analytical apparatus. The transfer path includes a loading station, a reagent delivery station, a mixing and washing station, a separating station and a discharging station.

Abstract: The aim of the present invention is to provide a solution to the problem of mixing in a vessel two or more substances of which at least one is a liquid phase. The vessel preferably comprises a container having an open upper end which may be advantageously surrounded by a rim, and a closed bottom end. The mixing device most preferably comprises a support plate adapted to receive the container and to allow engagement therewith by a rotating mixing cylinder. A single rotational movement e.g. from a drive motor acting through a drive cylinder, causes the rotating mixing cylinder to simultaneously engage the sample container and drive the bottom of the container in a circular motion around a vertical axis in order to generate a vortex in the substances to be mixed. Very effective, automated mixing of the substances is thereby effected.

Abstract: A container for determining antibodies or antigens in a biological liquid by the formation of specific antibody-antigen complexes, in which one partner element is initially associated with suspended magnetic particles that are subsequently regrouped against a collecting area of a first side wall of the container when the container is positioned within a magnetic field that extends through that area of the side wall. To prevent the particles from sliding down when the magnetic field is eliminated and to allow effective pipetting, the lower part of the side wall is adjacent to a planar surface formed at an obtuse angle to said side wall and tangent to a concave bottom surface that is itself tangent to a second side wall of the container located opposite to the first side wall.

Abstract: An apparatus responsive to optical changes in a waveguide when the latter is contacted with an analyte capable of reacting with a specific reactant thereto attached to the surface of said guide involves, for containing the analyte, an interchangeable round bottomed cuvette temporarily held by a suitably shaped carrier in working relationship with the optical components of the apparatus, this arrangement ensuring a correct optical orientation thereof relative to said component whatever the exact positioning of the cuvette.

Abstract: A cigarette is provided with an automatic valve responsive to the moisture content of the smoke for controlling induction of air into the smoke thereby compensating for the increase of nicotine concentration as the cigarette smokes down. The valve utilizes a bilamellar strip having sides of different hydrophilic character and distorting as a result of elongation of the more hydrophilic side.

Abstract: The viscosity of a fluid material, e.g. a synthetic-resin composition, or the coagulation of blood or plasma monitored by placing a quantity of the fluid substance on a support, directing a beam of light upon the sample, detecting reflected light from the sample and vibrating the support at a given frequency and amplitude to disturb its surface. The reflected light detected is a function of the viscosity or the degree of coagulation.