Abstract: An optical signal amplifier using a praseodymium doped fiber is described. The optical signal amplifier includes a signal laser, a first optical isolator, a second optical isolator a pump laser, a wave division multiplexer, a silica based glass optical fiber, a second optical isolator, an optical power meter, and an optical spectrum analyzer (OSA). The signal laser generates a signal laser beam. The pump laser generates a pumped laser beam. The wave division multiplexer combines the signal laser beam and the pumped laser beam and generates a combined laser beam. The silica based glass optical fiber has a preferred concentration of praseodymium ions of about 50×1024 ions/m3 and a length of about 5.7 m. The silica based glass optical fiber receives the combined laser beam, amplifies photons in the combined laser beam, and generates an amplified laser beam.

Abstract: A portable system is provided for measuring an analyte, such as acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user, and the application reports measurement data to a remote system.

Abstract: A breath analyte capture device includes a breath input port into which a user exhales a breath sample, and a cartridge insertion port for receiving a disposable cartridge containing an interactant. During exhalation of a breath sample, at least a portion of the breath sample is routed through the cartridge such that the analyte (such as breath acetone) is captured by the interactant. In some embodiments, the concentration of the analyte in the breath sample is measured by monitoring a chemical reaction that occurs in the disposable cartridge. The chemical reaction may be monitored by illuminating the cartridge at each of multiple light wavelengths while measuring reflected light.

Abstract: A wearable breath analysis device is disclosed that may be worn, for example, around the neck or wrist of a user. The wearable device may be a stand-along device (in which case it may include a display that provides a user interface), or may operate in conjunction with a smartphone or other command device. The wearable device may include auditory and/or vibratory notice and communications features or capabilities, for example, such as a reminder or notice to conduct a breath analyte measurement, instructions to the user in the course of conducting the measurement, and notice of the breath analyte measurement results. The auditory or vibratory notice may be provided at the wearable, and/or at the command device where a command device is used. Related methods also are provided.

Abstract: A breath analysis device into which a user exhales a breath sample is capable of venting an initial portion of the breath sample from the device, and routing a second portion of the breath sample into a disposable cartridge containing an interactant. The device may include a sensor, such as a pressure sensor, for detecting the initiation of exhalation, and may include a controller that switches a valve during the exhalation process to route a desired portion of the breath sample into the cartridge. After the exhalation process, an LED/photodiode arrangement, or another type of optical sensor, may be used to measure a color change produced by a chemical reaction in the cartridge, to thereby measure a concentration of a ketone or other analyte in the breath sample.

Abstract: A portable system is provided for measuring an analyte, such as acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user. The application tracks, and generates graphs of, the measurements, and may include various features for facilitating the analysis of the measurements.

Abstract: A system is disclosed that monitors participants in health-related programs, such as weight loss or exercise programs, and that provides automated, personalized health coaching to the program participants. The system includes breath analysis devices that are used by the program participants to generate ketone measurements, and includes a mobile application that runs on mobile devices of the participants and communicates with corresponding breath analysis devices. The system operates generally by monitoring ketone levels (such as acetone levels) and other attributes of the participants and by making personalized, machine-generated changes or updates to such programs to maintain program effectiveness and engagement. In some embodiments the system uses artificial intelligence to classify and coach the participants.

Abstract: A system is provided that includes a portable measurement device for measuring acetone in a breath sample of a user. The measurement device comprises a housing, a user-direct breath input device for engaging in direct fluid communication with a respiratory tract of the user and receiving the breath sample from the respiratory tract, a flow path disposed within the housing, a nanoparticle-based sensor disposed in the housing in fluid communication with the flow path and at an intermediate location between the upstream end and the downstream end, and a flow control device disposed in the housing and in the flow path between the upstream end and the nanoparticle-based sensor that prevents flow of the breath sample in an upstream direction opposite the downstream direction.

Abstract: A portable system is provided for measuring an analyte, such as acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user, and the application reports measurement data to a remote system.

Abstract: Systems and methods are provided for efficient handling of user requests to access shared resources in a distributed system, which handling may include throttling access to resources on a per-resource basis. A distributed load-balancing system can be logically represented as a hierarchical token bucket cache, where a global cache contains token buckets corresponding to individual resources whose tokens can be dispensed to service hosts each maintaining a local cache with token buckets that limit the servicing of requests to access those resources. Local and global caches can be implemented with a variant of a lazy token bucket algorithm to enable limiting the amount of communication required to manage cache state. High granularity of resource management can thus enable increased throttle limits on user accounts without risking overutilization of individual resources.

Abstract: A breath analyte capture device includes a breath input port into which a user exhales a breath sample, and a cartridge insertion port for receiving a disposable cartridge containing an interactant. During exhalation of a breath sample, at least a portion of the breath sample is routed through the cartridge such that the analyte (such as breath acetone) is captured by the interactant. In some embodiments, the concentration of the analyte in the breath sample is measured by monitoring a chemical reaction that occurs in the disposable cartridge. The chemical reaction may be monitored by illuminating the cartridge at each of multiple light wavelengths while measuring reflected light.

Abstract: A system is disclosed that monitors participants in health-related programs, such as weight loss or exercise programs, and that provides automated, personalized health coaching to the program participants. The system includes breath analysis devices that are used by the program participants to generate ketone measurements, and includes a mobile application that runs on mobile devices of the participants and communicates with corresponding breath analysis devices. The system operates generally by monitoring ketone levels (such as acetone levels) and other attributes of the participants and by making personalized, machine-generated changes or updates to such programs to maintain program effectiveness and engagement. In some embodiments the system uses artificial intelligence to classify and coach the participants.

Abstract: A portable system is provided for measuring an analyte, such as acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user. The application tracks, and generates graphs of, the measurements, and may include various features for facilitating the analysis of the measurements.

Abstract: A system is disclosed that uses profiles of users, including monitored ketone levels of the users, to assess effectiveness levels of health programs (such as weight loss programs) assigned to the users, and to select health program modifications for the users. The system may use a machine learning (artificial intelligence) algorithm to adaptively learn how to classify users and to select messaging and behavioral modifications for the users. For example, in some embodiments the system classifies the users and provides associated health program recommendations using a computer model trained with expert-classified user data records. As another example, a set of rules may be used to generate the health program recommendations and related messaging, and the set of rules may automatically be modified over time based on feedback data reflective of health program effectiveness levels produced by such rules.

Abstract: A portable system is provided for measuring a ketone, such as an acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding ketone measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user. The application tracks, and generates graphs of, the ketone measurements, and may include various features for facilitating the analysis of the measurements. One such feature compares ketone measurements taken while the user is on a health program to a baseline level determined from pre-program-initiation ketone measurements.

Abstract: A system is disclosed that monitors participants in health-related programs, such as weight loss or exercise programs, and that provides automated, personalized health coaching to the program participants. The system includes breath analysis devices that are used by the program participants to generate ketone measurements, and includes a mobile application that runs on mobile devices of the participants and communicates with corresponding breath analysis devices. The system operates generally by monitoring ketone levels (such as acetone levels) and other attributes of the participants and by making personalized, machine-generated changes or updates to such programs to maintain program effectiveness and engagement. In some embodiments the system uses artificial intelligence to classify and coach the participants.

Abstract: A system is disclosed that uses profiles of users, including monitored ketone levels of the users, to assess effectiveness levels of health programs (such as weight loss programs) assigned to the users, and to select health program modifications for the users. The system may use a machine learning (artificial intelligence) algorithm to adaptively learn how to classify users and to select messaging and behavioral modifications for the users. For example, in some embodiments the system classifies the users and provides associated health program recommendations using a computer model trained with expert-classified user data records. As another example, a set of rules may be used to generate the health program recommendations and related messaging, and the set of rules may automatically be modified over time based on feedback data reflective of health program effectiveness levels produced by such rules.

Abstract: Various devices are disclosed for measuring the concentration of an analyte, such as acetone, in a breath sample. The disclosed devices include a disposable cartridge containing a reactive material that extracts the analyte from a breath sample passed through the cartridge. In some embodiments, the cartridge contains a solid, porous structure (such as a disk, bowl or puck) that contains the reactive material. The porous structure may be created by mixing reactive particles with resin particles, and then using a sintering process to transform the mixture into a solid structure. Also disclosed are devices for routing a breath sample through the cartridge during exhalation, and for analyzing a reaction in the cartridge to measure a concentration of the analyte.

Abstract: A breath analyte capture device includes a breath input port into which a user exhales a breath sample, and a cartridge insertion port for receiving a disposable cartridge containing an interactant. During exhalation of a breath sample, at least a portion of the breath sample is routed through the cartridge such that the analyte (such as breath acetone) is captured by the interactant. In some embodiments, the concentration of the analyte in the breath sample is measured by monitoring a chemical reaction that occurs in the disposable cartridge. The chemical reaction may be monitored by illuminating the cartridge at each of multiple light wavelengths while measuring reflected light.

Abstract: A system is provided that includes a portable measurement device for measuring acetone in a breath sample of a user. The measurement device comprises a housing, a user-direct breath input device for engaging in direct fluid communication with a respiratory tract of the user and receiving the breath sample from the respiratory tract, a flow path disposed within the housing, a nanoparticle-based sensor disposed in the housing in fluid communication with the flow path and at an intermediate location between the upstream end and the downstream end, and a flow control device disposed in the housing and in the flow path between the upstream end and the nanoparticle-based sensor that prevents flow of the breath sample in an upstream direction opposite the downstream direction.