Massachusetts Institute of Technology

Kerry Alexander Johnson

John Francis Barry

Danielle Ann Braje

Linh M Pham

Hannah Anne Clevenson

Christopher Michael McNally

Carson Arthur Teale

Robert Samuel Langer

Carlo Giovanni Traverso

Trina Rae Vian

Joseph John Lacirignola

David Christopher Maurer

Albert Joseph Swiston

Edward H Chen

David Francis Aubin, Jr

Christopher J Smalt

Paula P Collins

Christine Michelle Weston

Tadd Bernard Hughes

Erik M Thompson

Paul T Calamia

Shakti Davis

Olha Townsend

Mary Katherine Byrd

A magnetometer containing a crystal sensor with solid-state defects senses the magnitude and direction of a magnetic field. The solid-state defects in the crystal sensor absorb microwave and optical energy to transition between several energy states while emitting light intensity indicative of their spin states. The magnetic field alters the spin-state transitions of the solid-state defects by amounts depending on the solid-state defects' orientations with respect to the magnetic field. The optical read out, reporting the spin state of an ensemble of solid-state defects from one particular orientation class, can be used to lock microwave signals to the resonances associated with the spin-state transitions. The frequencies of the locked microwave signals can be used to reconstruct the magnetic field vector.

Methods and apparatus for optically detecting magnetic resonance

Applying a bias magnetic field to a solid-state spin sensor enables vector magnetic field measurements with the solid-state spin sensor. Unfortunately, if the bias magnetic field drifts slowly, it creates noise that confounds low-frequency field measurements. Fortunately, the undesired slow drift of the magnitude of the bias magnetic field can be removed, nullified, or cancelled by reversing the direction (polarity) of the bias magnetic field at known intervals. This makes the resulting solid-state spin sensor system suitable for detecting low-frequency (mHz, for example) changes in magnetic field or other physical parameters.

Chopped bias magnetic field solid-state spin sensor for low frequency measurements of physical quantities

Systems, apparatus, and methods for collecting, interpreting, and utilizing noise exposure data may include sensors to obtain an analog signal representative of impulse noise sound pressure and an analog signal representative of continuous noise sound pressure. At least one ADC may generate digital signals by sampling the analog signals at rates equal to or greater than twice the reciprocal of a minimum impulse noise rise time. Accelerometers may obtain data in close proximity to and remote from the sensors. At least one processor may include a first combining node to combine the digital signals to represent both the continuous noise and the impulse noise, a shock-artifact detection filter to identify a time frame including a shock artifact based on the accelerometry data, a frequency filter to generate a background-removed audio signal, an adaptive filter to estimate the shock artifact, and a second combining node to produce a shock-artifact-free audio signal.

High fidelity systems, apparatus, and methods for collecting noise exposure data

Reliable, real-time heart and respiratory rates are key vital signs used in evaluating the physiological status in many clinical and non-clinical settings. Measuring these vital signs generally requires superficial attachment of physically or logistically obtrusive sensors to subjects that may result in skin irritation or adversely influence subject performance. Given the broad acceptance of ingestible electronics, the approach disclosed here enables vital sign monitoring internally from the gastrointestinal tract. The large animal (porcine) experiments and a robust processing disclosed herein demonstrate the feasibility of this approach. Implementing vital sign monitoring as a stand-alone technology or in conjunction with other ingestible devices has the capacity to significantly aid telemedicine, optimize performance monitoring of athletes, military service members, and first-responders, as well as provide a facile method for rapid clinical evaluation and triage.

Ingestible devices and methods for physiological status monitoring

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Somerville, MA, United States of America

Kerry Alexander Johnson