An instrument determines a concentration of bacteria in a plurality of fluid samples, and comprises a housing, a rotatable platform, a plurality of fluid containers, a light source, a sensor, and a motor. The rotatable platform is within the housing. The fluid containers are located on the rotatable platform. Each fluid container holds a corresponding one of the plurality of fluid samples, and has an input window and an output window. The light source provides an input beam for transmission into the input windows of the fluid containers and through the corresponding fluid samples. The input beam creates a forward-scatter signal associated with the concentration of bacteria. The motor rotates the rotatable platform so that the input beam sequentially passes through each fluid sample. A sensor within the housing detects the forward-scatter signal exiting from the output window associated with the fluid sample receiving the input beam.

Described are devices, methods, and systems that are suitable for rapidly and simultaneously determining the concentration of suspended particles in a sample. The devices, methods, and systems allow for the rapid and simultaneous interrogation of a large number of sample wells in a single vessel, for example, samples contained in a two-dimensional array or micro-titer plate, without the need for moving reading heads or moving the sample vessel. The nephelometry system allows the user to rapidly and simultaneously measure the concentration of the particles in numerous samples, adjust the concentration of the particles in the sample with a sample handling system, and re-measure the concentration of the samples in order to achieve a desired concentration.

A method for detecting and counting particles suspended in fluids, such as bacteria suspended in urine, utilizing dynamic features of the suspended particles and employing light scattering measurements. The disclosed method is suitable for determining the susceptibility of bacteria to antibiotics. A cuvette for detecting bacteria in fluids, which is especially suited for the light scattering measurements, is provided.

The present disclosure describes a flow cell, a read head, and a skid attachment for measuring real-time molecular weight for downstream process control. In an embodiment, the flow cell comprises a hollow cylindrical tube, an inlet flange connected to an inlet of the tube, and an outlet flange connected to an outlet of the tube. In an embodiment, the read head comprises at least one push rod, at least two line contacts, where the at least one push rod is configured to push an outer side wall of a flow cell against the at least two line contacts. In an embodiment, the skid attachment comprises a plurality of arms connected to an enclosure configured to house at least a multi-angle light scattering instrument comprising a read head.

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.

A method for calibrating a dark field microcopy setup is disclosed. The method includes preparing a plurality of particle samples, each with a known concentration and particle size, the plurality having more than one particle size and, optionally, more than one refractive index and more than one diluent. For each sample in the plurality, the sample is measured in the setup and the scattered light intensity and number of particles is measured. From this data, a relationship between the scattered light intensity, particle size and calibrated investigated volume can be determined. The calibrated investigated volume is used to obtain the proper particle size distribution in a given diluent.

A system and method for the real time determination of microbial growth in or on perishable products. The system can predict the extent of microbial growth, e.g., whether food is spoiled, in real time by measuring chemicals released, e.g., CO.sub.2, from the perishable product during microbial growth. The output from a sensor can be correlated to the extent of microbial growth, i.e., spoilage, and provide information about the extent of microbial growth to the user, for example, through their smart devices.

An optical measurement instrument is an integrated instrument that includes an optical cavity with a light source, a sample cuvette, and an optical sensor. The instrument can be used for taking measurements of organism concentration in one or more samples. Preferably, the instrument holds multiple, individually-loaded, independent fluid samples and determines bacteria concentration via a forward-scattering signal. The instrument can incorporate onboard incubation to promote bacterial growth in the samples such that, once a certain bacterial concentration is achieved, the higher concentration sample can be used with a mass spectrometer to identify the type of bacteria. The instrument and mass spectrometer can be a part of a network for medical diagnostic testing data where data is stored in a manner that is inherently untainted by patient identifiable information.

A system comprising at least one light source configured to generate a light at specific wavelengths and project the light over an optical path, a sample device, the sample device configured to receive a sample obtained from a person, the sample device being transparent and being at least partially within the optical path, a diversifier including occlusions for scattering coherent light received from the light source along the optical path, a first detector configured to receive the light over the optical path and from at least a portion of the diversifier, the detector configured to detect spectral intensities of the light, and a second detector configured to receive at least a portion of the light form the optical path before the light passes through the diffuser, the second detector configured to detect spectral intensities of the light.

A method for calibrating a dark field microcopy setup is disclosed. The method includes preparing a plurality of particle samples, each with a known concentration and particle size, the plurality having more than one particle size and, optionally, more than one refractive index and more than one diluent. For each sample in the plurality, the sample is measured in the setup and the scattered light intensity and number of particles is measured. From this data, a relationship between the scattered light intensity, particle size and calibrated investigated volume can be determined. The calibrated investigated volume is used to obtain the proper particle size distribution in a given diluent.