A nanopore device measures a current signal Is that flows through the nanopore device, which has an aperture and an electrode pair. A transimpedance amplifier converts the current signal Is into a voltage signal Vs. A voltage source is configured to apply a DC bias voltage Vb across the electrode pair in a normal measurement mode, and to apply a calibration voltage Vcal across the electrode pair in a calibration mode. In the calibration mode, at least one circuit constant of a measurement apparatus is calibrated based on the output signal Vs of the transimpedance amplifier and the calibration voltage Vcal.

This disclosure relates to reagents and their use for elemental imaging mass spectrometry of biological samples.

The present disclosure relates to a method for measuring the cell concentration in a sample, comprising the following steps: (1) measuring the concentrations of cells in standard samples each having a known concentration using a flow cytometer; (2) preparing a calibration curve based on the values measured in step (1) and the known concentrations; (3) measuring the concentration of cells in a sample having an unknown concentration using a flow cytometer; and (4) determining the concentration of cells from the value measured in step (3) based on the calibration curve prepared in step (2).

An apparatus and method for generating a controlled, predictable, reproducible and variable-size distribution of particulate matter (PM), particle number (PN) and/or facsimile/simulation, derived from vaporizing and condensing a specialized liquid, utilizing a vapor delivery device; a filter capability so as to remove a significant amount of ambient PM/PN as a secondary calibration process for the identification of fine and ultra-fine particles (e.g., 0.3 micrometers and smaller) as well as a computer-controlled ability to perform a pre-determined series of calibration routines, housed in a container.

For an easy calibration using calibration particles, provided is a measuring device to capture images of target objects. An image analyzer acquires multiple images obtained at a predetermined time interval, (a) specifies the mean-square displacement of a bright point of a calibration particle based on the displacement of the bright point of the calibration particle in the multiple images in a calibration mode, and (b) specifies the mean-square displacement of a bright point of the target particle based on the displacement of the bright point of the target particle in the multiple images in a measurement mode. A particle size analyzer (c) derives the particle size of the target particle from the mean-square displacement of the bright point of the target particle based on the mean-square displacement of the bright point of the calibration particle and the particle size of the calibration particle in an analysis mode.

Aspects of the present disclosure include methods for adjusting sensitivity of a photodiode in a light detection system. Methods according to certain embodiments include determining a background data signal from a photodetector at a plurality of detector gains, irradiating the photodetector with a light source at a plurality of different light intensities, generating data signals from the photodetector for the plurality of light intensities at each detector gain and adjusting the photodetector to the detector gain that corresponds to the lowest light irradiation intensity that generates a data signal resolvable from the background data signal. Systems (e.g., particle analyzers) having a light source and a light detection system that includes a photodetector for practicing the subject methods are also described. Non-transitory computer readable storage medium are also provided.

A modular optical particle counter sensor and apparatus are described that consolidates counting functionality on a single main counter board and has expandable functionality through connections to plug-in system boards. The modular optical particle sensor may be directly connected to a manifold with an integrated venturi for better controlling the flow rate of the air stream passing through the apparatus for sampling.

A method for calibrating a particle sensor includes focusing a laser beam on a calibration plane for generating a calibration intensity distribution in the calibration plane. A calibration plate is arranged in the calibration plane. Contrast regions for modulating an intensity of the laser beam are formed on the calibration plate. The method further includes moving the calibration plate and/or the calibration intensity distribution in the calibration plane, recording at least one intensity signal of the laser beam, following passage through the calibration plane, and calibrating the particle sensor by evaluating the at least one intensity signal.

Aspects of the present disclosure include methods for determining a parameter of a photodetector (e.g., a photodetector in a particle analyzer). Methods according to certain embodiments include irradiating a photodetector positioned in a particle analyzer with a light source (e.g., a continuous wave light source) at a first intensity for a first predetermined time interval, irradiating the photodetector with the light source at a second intensity for a second predetermined time interval, integrating data signals from the photodetector over a period of time that includes the first predetermined interval and the second predetermined interval and determining one or more parameters of the photodetector based on the integrated data signals. Systems (e.g., particle analyzers) having light source and a photodetector for practicing the subject methods are also described. Non-transitory computer readable storage medium having instructions stored thereon for determining a parameter of a photodetector according to the subject methods are also provided.

Aspects of the present disclosure include methods for adjusting sensitivity of a photodiode in a light detection system. Methods according to certain embodiments include determining a background data signal from a photodetector at a plurality of detector gains, irradiating the photodetector with a light source at a plurality of different light intensities, generating data signals from the photodetector for the plurality of light intensities at each detector gain and adjusting the photodetector to the detector gain that corresponds to the lowest light irradiation intensity that generates a data signal resolvable from the background data signal. Systems (e.g., particle analyzers) having a light source and a light detection system that includes a photodetector for practicing the subject methods are also described. Non-transitory computer readable storage medium are also provided.