The invention relates to methods and apparatus for determining properties of a surface. Embodiments disclosed include an apparatus for measuring a surface charge of a sample, comprising: a sample holder having an opposed pair of electrodes and configured to hold a sample in position in a measurement volume between the electrodes such that a planar surface of the sample is aligned orthogonal to the electrode surfaces; a measurement chamber for containing a measurement liquid and having an open end configured to receive the sample holder to position the electrodes in a preset orientation; a laser light source positioned and configured to direct a laser beam through the measurement chamber between the electrodes and parallel to the planar surface of the sample when the sample holder is received in the measurement chamber; and a detector positioned and configured to detect scattered light from the measurement volume, wherein the apparatus is configured to allow for detection of the scattered light by the detector over a range of distances from the surface of the sample.

Although a more accurate estimate of a person's risk of cardiovascular disease can be made on the basis of the number of lipoprotein particles per unit volume in the person's blood, current methods all rely on measuring the mass of lipoprotein cholesterol per unit volume. It has been discovered that a rapid and accurate lipoprotein particle count can be obtained by photometry. A method and apparatus are provided for measuring the number of lipoprotein particles in a sample using photometry.

An assay-protocol-specific multi-channel fluid-dispenser cassette for an automated assay fluid dispensing system may include a structure with multiple fluid channels within the structure to contain and control respective assay fluids. Each fluid channels may have an outlet. A driver interface may be carried by the structure removably and mechanically engageable with a dispenser driver of a dispenser so that the dispenser driver can control the dispensing of fluids from the structure directly onto underlying reaction sites while each of the fluid channels remain as part of the structure. An assay-protocol-indicative cassette-type identifier may be formed in or attached to the structure and indicative of different assay protocols for all of the multiple fluid channels. The assay-protocol-cassette-type identifier may be readable by the cassette driver in response to the multi-channel fluid-dispenser cassette being removably connected to the dispenser.

There is provided a microchip including at least two substrates each comprising a thermoplastic resin, and at least one member comprising a material having a heat distortion temperature higher than a heat distortion temperature of the thermoplastic resin, the at least one member including at least one engagement end including a protrusion extending between the at least two substrates, wherein the at least one member is fixed to the at least two substrates by the protrusion being held between the at least two substrates by at least one wall surface that is thermally deformed by thermocompression.

Although a more accurate estimate of a person's risk of cardiovascular disease can be made on the basis of the number of lipoprotein particles per unit volume in the person's blood, current methods all rely on measuring the mass of lipoprotein cholesterol per unit volume. It has been discovered that a rapid and accurate lipoprotein particle count can be obtained by photometry. A method and apparatus are provided for measuring the number of lipoprotein particles in a sample using photometry.

A fluid analysis system may include a stage configured to receive a sample holder including a fluid sample to be analyzed. The fluid analysis system may also include a fluid analyzer configured to monitor at least one characteristic of the fluid sample to be analyzed; and an inclined rail; wherein the stage is configured to move along the inclined rail to cause the sample holder to move with a first component of motion along an analysis axis of the fluid analyzer and simultaneously with a second component of motion orthogonal to the analysis axis of the fluid analyzer, wherein the first component of motion affects a focus of the fluid analyzer relative to at least one constituent of the fluid sample to be analyzed.

The present disclosure relates to a sensor arrangement for determining the turbidity of a liquid medium. The sensor arrangement includes a sensor section with at least one light source for sending transmission light into a measuring chamber, and at least one receiver associated with the light source for receiving reception light from the measuring chamber, wherein the transmission light is converted into the reception light in the measuring chamber by the medium by means of scattering at a measurement angle, and the reception light received by the receiver is a measure of the turbidity. The reception light is back reflected at a reflection element in contact with the medium, whereby an optical path from the light source through the measuring chamber to the reflection element and from the reflection element through the measuring chamber to the receiver results.

An automatic analysis apparatus is capable of replacing circulated water in a reaction vessel and continuously cooling a light source lamp without stopping an operation for measuring a specimen. In an operation state, a drain electromagnetic valve 49 is opened to drain reaction vessel water outside and when the water level reaches a measurement limit water level, the drain electromagnetic valve 49 is closed. The reaction vessel water is supplied by starting a water supply pump, opening a water supply electromagnetic valve and when the water level has reached a full water level, the water supply electromagnetic valve is closed, and the water supply pump is stopped. In a state other than the operation state, the reaction vessel water is drained outside. When the water level has reached a circulation limit water level, the drain electromagnetic valve is closed.

Systems for analyzing fluids (e.g., gases) include a chamber structure with a reflective inner surface, emitters, a primary detector positioned to principally detect electromagnetic energy reflected numerous times through the gas(es) and a calibration detector positioned to detect electromagnetic energy not reflected numerous times through the gas(es). Calibration may be automatically performed. The primary detector relies principally on Raleigh scattering. An optional primary detector may be positioned to principally detect Raman scattered electromagnetic energy.

The present invention is a cuvette assembly for use in optically measuring at least one characteristic of particles within a plurality of liquid samples. The cuvette assembly comprises a main body having internal walls and external walls, and a plurality of cuvettes within the main body at least partially being defined by the internal walls. Each of the plurality of cuvettes has a liquid-input chamber for receiving a respective one of the plurality of liquid samples, a filter, and an optical chamber for receiving a respective filtered liquid sample caused by passing the respective one of the plurality of liquid samples through the filter. Each of the optical chambers includes an entry window for allowing transmission of an input light beam through the filtered liquid sample and an exit window for transmitting a forward scatter signal caused by the particles within the filtered liquid sample.