A photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and/or pull of the device, a user's hair, a user's skin pigmentation, and/or motion. The PPG device can further include one or more lenses and/or reflectors to increase the signal strength and/or and to obscure the optical components and associated wiring from being visible to a user's eye.

A method of detecting natural gas releases that includes the step of traversing a target area with a gas-filter correlation radiometer having a field of view oriented towards the target area. The gas-filter correlation radiometer receives reflected radiation in a passband from the target area and produces gas-filter correlation radiometer signals from the received reflected radiation. A surface reflectivity spectral profile of the target area is determined. The presence of methane in the target area is then determined based upon the received reflected radiation and the surface reflectivity spectral profile of the target area.

A gas concentration sensor is includes an integrated die-form electromagnetic radiation source and an integrated die-form infrared detector. In one or more implementations, the gas concentration sensor includes a package substrate defining at least one aperture, a gas permeable mesh coupled to the package substrate and covering at least a portion of the at least one aperture, a die-form electromagnetic radiation source positioned in an interior region of the package substrate, a die-form detector positioned in the interior region of the package substrate, and control circuitry operably coupled to the die-form detector and configured to detect and calibrate one or more signal outputs from the die-form detector to determine a gas concentration within the interior region of the package substrate. The gas concentration sensor can be configured for specific detection of various gases through control of the spectral wavelengths emitted by the electromagnetic radiation source(s) and/or detected by the detector(s).

Implementations are described herein for isolating mirrors and/or other potentially-vulnerable components of multi-pass optical systems from samples being analyzed, while mitigating interference and/or reduction in optical power. In one implementation, an apparatus may include: an optical cell with one or more passages, the one or more passages provided for introducing a sample into an interior of the optical cell for analysis and for removing the sample from the interior; a first mirror with a first reflective surface that faces the interior of the optical cell; one or more additional mirrors with one or more corresponding additional reflective surfaces that face the first reflective surface of the first mirror; and a wedge-shaped optical element positioned between the first mirror and the interior of the optical cell.

According to one embodiment, a sensor includes a nonmagnetic layer and a plurality of magnetic field sensors. The nonmagnetic layer has a first surface and a second surface. The magnetic field sensors are arranged along the second surface. The second surface is between the first surface and the magnetic field sensors. Each of the magnetic field sensors includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the nonmagnetic layer, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. The intermediate layer is nonmagnetic. A distance between the first surface and the second magnetic layer is not more than a pitch of the magnetic field sensors.

The present invention relates generally to the field of chemical and biological sensors and in particular to micro electro-mechanical systems (MEMS) sensors for measuring fluid viscosity and detection of minute amounts of chemicals and biological agents in fluids. It is an object of the present invention to provide a sensor that will work in disposable cartridges with remote sensing that can measure dynamic changes of the functionalized cantilevers in liquid and gas environment.

The invention relates to cleavable chemistry in general, and in particular, to tunable fluorescence using cleavable linkers present in fluorochrome-quencher conjugates.

Methods, apparatuses and systems for detecting multiple gaseous substances for detecting a plurality of target gaseous substances or chemical compositions, using, for example, a high-speed, tunable gas detecting apparatus. An example gas detecting apparatus may comprise: a light source configured to generate a light beam, a moveable mirror component configured to move between a plurality of positions, wherein each position of the moveable mirror component is associated with a narrow band corresponding with a gas absorption frequency range of a target gaseous substance or chemical composition, at least one optical component configured to condition an output light beam of the moveable mirror component, wherein a measurable attenuated optical signal is generated responsive to exposing a sample gaseous substance to the conditioned output light beam.

This invention relates to a method of and system for facilitating detection of a particular predetermined gas in a scene under observation. The gas in the scene is typically associated with a gas leak in equipment. To this end, the system comprises an infrared camera arrangement; a strobing illuminator device having a strobing frequency matched to a frame rate of the camera; and a processing arrangement. The processing arrangement is configured to store a prior frame obtained via the infrared camera arrangement; and compare a current frame with the stored prior frame and generate an output signal in response to said comparison. The system also comprises a display device configured to display an output image based at least on the output signal generated by the processing arrangement so as to facilitate detection of the particular predetermined gas, in use.

Biomarkers of high blood pressure are measured to identify high blood pressure of the subject based on one or more biomarkers. In many embodiments, the response of the biomarker to blood pressure occurs over the course of at least an hour, such that the high blood pressure identification is based on a cumulative effect of physiology of the subject over a period of time. The methods and apparatus of identifying high blood pressure with biomarkers have the advantage of providing improved treatment of the subject, as the identified biomarker can be related to an effect of the high blood pressure on the subject, such as a biomarker corresponding to central blood pressure. The sample can be subjected to increases in one or more of pressure or temperatures, and changes in the blood sample measured over time.