Abstract: This disclosure relates to methods for measuring one or more physiological signals while the user is engaged in a predetermined activity. Exemplary predetermined activities can include activities such as walking, climbing stairs, biking, and the like. The physiological measurements can include, but are not limited to, heart rate signals. The physiological measurements may be affected by the predetermined activity, so the system may be configured to employ one or more criteria prior to measuring physiological information to minimize the effects. The one or more criteria can include, but are not limited to, an inter-sampling waiting time, continuous motion criteria, predetermined activity criteria, a post-physiological measurement amount of time, and a confidence value. The continuous motion criteria can be based on the type of predetermined activity. For example, walking may have walking state criteria and a step count criteria.

Abstract: Embodiments of the present disclosure can provide systems, methods, and computer-readable medium for tracking the heartrate of a user using different techniques associated with different contexts. For example, motion of a user wearing a wearable device can be tracked using at least first sensors of the one or more sensors. The physical state of the user can also be tracked using at least second sensors of the one or more sensors. In some cases it can be determines whether an application of the wearable device has been launched. Additionally, an activity category of the user can be determined based at least in part on the motion of the user, the physical state of the user, and/or whether the application has been launched. Heartrate data of the user can be collected, and the heartrate data can be categorized based at least in part on the determined category.

Abstract: This relates to methods for measuring irregularities in a signal and corresponding devices. The devices can include a PPG sensor unit configured to detect multiple occurrences of a given event in the measured signal(s) over a sampling interval. In some instances, the device can register the occurrences of the events. In some examples, the device can include one or more motion sensors configured to detect whether the device is in a low-motion state. The device may delay initiating measurements when the device is not in a low-motion state to enhance measurement accuracy. Examples of the disclosure further include resetting the sample procedure based on one or more factors such as the number of non-qualifying measurements. In some examples, the device can be configured to perform both primary and secondary measurements, where the primary measurements can include readings using a set of operating conditions different from the secondary measurements.

Abstract: A device for determining a heart rate of a user has a PPG sensor and an accelerometer to compensate for acceleration artifacts within the PPG signal. The device transforms time domain PPG and accelerometer signals into the frequency domain using a Fourier transformation and utilizes the Fourier coefficient magnitudes as indicative of the probability of candidate heart rate values. Candidate heart rate values are determined at sampling times over a time interval and a most probable heart rate path during the time interval is determined using a reward/penalty algorithm.

Abstract: A device for determining a heart rate of a user has a PPG sensor and an accelerometer to compensate for acceleration artifacts within the PPG signal. The device transforms time domain PPG and accelerometer signals into the frequency domain using a Fourier transformation and utilizes the Fourier coefficient magnitudes as indicative of the probability of candidate heart rate values. Candidate heart rate values are determined at sampling times over a time interval and a most probable heart rate path during the time interval is determined using a reward/penalty algorithm.

Abstract: A photoplethysmogram (PPG) signal may be obtained from a pulse oximeter, which employs a light emitter and a light sensor to measure the perfusion of blood to the skin of a user, and multiple wavelengths of light may be employed. For various wavelengths, relatively long wavelengths may interrogate relatively deep blood vessels in comparison to relatively short wavelengths, which may interrogate relatively shallow blood vessels. Accordingly, for co-located emitters of different wavelengths, there may be a time delay in the pulse signal measured by each wavelength. The time delay as a function of time may vary according to the constriction and dilation of the blood vessels, which itself may vary according to the respiratory rate of a user.

Abstract: A device for determining a heart rate of a user has a PPG sensor and an accelerometer to compensate for acceleration artifacts within the PPG signal. The device transforms time domain PPG and accelerometer signals into the frequency domain using a Fourier transformation and utilizes the Fourier coefficient magnitudes as indicative of the probability of candidate heart rate values. Candidate heart rate values are determined at sampling times over a time interval and a most probable heart rate path during the time interval is determined using a reward/penalty algorithm.

Abstract: An algorithm for removing motion artifacts from the PPG signal in the time domain to determine heart rate is disclosed. A device for determining a heart rate of a user can include a heart rate sensor configured to generate heart rate signals when positioned on or adjacent to a user's skin, an accelerometer configured to generate one or more acceleration signals, and processing circuitry configured to remove, in a time domain, motion artifacts from the heart rate signals based on the acceleration signals. In some examples, the removal of motion artifacts can also be based on mean-centered, variance-scaled integrated acceleration signals. In some examples, the processing circuitry can be configured to remove motion artifacts using a least squares algorithm to identify a best representation of acceleration and integrated acceleration signals in the heart rate signals.

Abstract: Embodiments in accordance with the present invention relate to techniques for the growth and attachment of single wall carbon nanotubes (SWNT), facilitating their use as robust and well-characterized tools for AFM imaging and other applications. In accordance with one embodiment, SWNTs attached to an AFM tip can function as a structural scaffold for nanoscale device fabrication on a scanning probe. Such a probe can trigger, with nanometer precision, specific biochemical reactions or conformational changes in biological systems. The consequences of such triggering can be observed in real time by single-molecule fluorescence, electrical, and/or AFM sensing. Specific embodiments in accordance with the present invention utilize sensing and manipulation of individual molecules with carbon nanotubes, coupled with single-molecule fluorescence imaging, to allow observation of spectroscopic signals in response to mechanically induced molecular changes.

Abstract: A method for fabricating assembled structures. The method includes providing a tip structure, which has a first end, a second end, and a length defined between the first end and the second end. The second end is a free end. The method includes attaching a nano-sized structure along a portion of the length of the tip structure to extend a total length of the tip structure to include the length of the tip structure and a first length associated with the nano-sized structure. The method includes shortening the nano-sized structure from the first length to a second length. The method also includes pushing the nano-sized structure in a direction parallel to the second length to reduce the second length to a third length of the nano-sized structure along the direction parallel to the second length to cause the nano-sized structure to move along a portion of the length of the tip structure.