Sag propensity of a fluid can be determined by applying an oscillatory strain at an amplitude in excess of a linear region and below a yield strain of the drilling fluid. This may include use of medium amplitude oscillatory shear (MAOS), from which an elastic modulus of the fluid is determined. The elastic modulus may be determined over time, from which a time to reach maximum elastic modulus can be determined. The time to reach maximum elastic modulus is then converted or correlated to a drilling fluid sag propensity for the drilling fluid either in absolute terms or in relation to base or comparison fluids. Such an evaluation can be performed using a torsional resonance device in which the oscillatory strain is controllable so as to be maintained relatively constant during the measurement.

Devices and methods are described for measuring formed blood component sedimentation rate. Some of the methods may use (1) centrifugal techniques for separating red blood cells from plasma and (2) video and/or still imaging capability. Both may be used alone or in combination to accelerate formed blood component sedimentation and to measure its rate. In one example, the method may advantageously enable rapid measurement of sedimentation rate using small blood sample volumes. Automated image analysis can be used to determine both sedimentation rate and hematocrit. Automated techniques may be used to compensate for effects of hematocrit on uncorrected sedimentation rate data.

The disclosed Hydro-Gravitational Trap (HGT) method and apparatus separate a suspension into two flow streams, discriminating particles based on a designated particle settling velocity: one Designated Particle Concentrated (DPC) and one Designated Particle Diluted (DPD). The HGT confines particles between a controlled upward hydrodynamic field and the downward net gravitational field within the apparatus’s High-Energy Segment (HES), awaiting removal. The HES typically contains an internal agitator conforming to its divergent shape. Agitator motion prevents trapped particles from adhering to the HES, provides flocculation energy, and mixes the contents, controlling the DPC flow stream concentration. The agitator can also simultaneously function as a control valve or an actuator regulating this flow in some preferred embodiments. Designated particles remain trapped in the HES until removed with the DPC flow stream while the DPD flow stream advects upward, exiting the apparatus through the top of the Low-Energy.sup.1 Segment (LES).

A method and device performing the method for estimation of cell count, such as sperm cell count, is disclosed. The device may be a kit including a cartridge configured to hold fluid, such as seminal fluid, and an instrument configured to centrifuge the cartridge. The cartridge and instrument are configured such that, during operation or centrifugation, they are securely attached to each other. The cartridge has a component with a defined cross-sectional volume. The defined cross-sectional volume is used to mark the component with markings, allowing a user of the device to read the markings and estimate cell volume and, thus, concentration. Various embodiments of the device are disclosed.

A particle size distribution measurement device includes a cell holding body 31 that holds a measurement cell 2 containing a measurement sample and a dispersion medium and a reference cell 6 containing a reference sample and is rotated by a motor 322, and a cell discrimination mechanism 7 that discriminates the cells 2, 6 passing through a predetermined rotation position by using a magnetic force or electrostatic capacitance.

A method and system for processing particles contained in a liquid biological sample is presented. The method uses a rotatable vessel for processing particles contained in a liquid biological sample. The rotatable vessel has a longitudinal axis about which the vessel is rotatable, an upper portion having a top opening for receiving the liquid containing the particles, a lower portion for holding the liquid while the rotatable vessel is resting, the lower portion having a bottom, and an intermediate portion located between the upper portion and the lower portion, the intermediate portion having a lateral collection chamber for holding the liquid while the rotatable vessel is rotating. The method employs dedicated acceleration and deceleration profiles for sedimentation and re-suspension of the particles of interest.

Provided herein are methods to characterize preparations of recombinant viral particles using analytical ultracentrifugation. Recombinant viral particles include recombinant adeno-associated viral particles, recombinant adenoviral particles, recombinant lentiviral particles and recombinant herpes simplex virus particles. Variant species of recombinant viral particles including empty capsids and recombinant viral particles with variant genomes (e.g., truncated genomes, aggregates, recombinants) can be identified and quantitated. The methods can be used to characterize preparations of recombinant viral particles regardless of the sequence of the recombinant viral genome or the serotype of the recombinant viral capsid.

An apparatus for determining a vertical position of at least one interface between a first component and at least one second component, the components comprised as different layers in a sample container. The apparatus comprises a first sensing unit and a first light detector configured to generate a first sensing signal, a second sensing unit comprising a second light detector configured to generate a second sensing signal, a driving unit configured to move the sample container, a position sensing unit configured to output a position sensing signal indicative of a vertical position of the sample container, a vertical position determining unit configured to match the first and the second sensing signal such that first and the second sensing signal correspond to identical vertical positions, and to determine the vertical position of the at least one interface in response to the matched sensing signals and the position sensing signal.

Provided herein are methods to characterize preparations of recombinant viral particles using analytical ultracentrifugation. Recombinant viral particles include recombinant adeno-associated viral particles, recombinant adenoviral particles, recombinant lentiviral particles and recombinant herpes simplex virus particles. Variant species of recombinant viral particles including empty capsids and recombinant viral particles with variant genomes (e.g., truncated genomes, aggregates, recombinants) can be identified and quantitated. The methods can be used to characterize preparations of recombinant viral particles regardless of the sequence of the recombinant viral genome or the serotype of the recombinant viral capsid.

An in-situ measurement apparatus automatically draws aqueous samples on an intermittent or ad-hoc basis and measures specific metal specie concentration. The apparatus can perform both raw measurement of specific metal specie, as well as processing to convert other species of the same metal to the specific metal specie or to destroy or remove unwanted masking agents (e.g. organics). In one application, “dirty” water from a scrubber is measured for Se(IV) presence (using a renewable voltametric system), both with and without the masking agents present; in addition, selective processing converts other selenium species to Se(IV), permitting assessment of total selenium and measurement of Se(VI) presence. Automated reactions can then be taken to remove detected toxic substances from waste water without excess reliance on treatment chemicals, and so as to ensure that only water complaint with regulatory standards is released into the environment.