Neural network-based arterial diameter estimation from ultrasound data.

Cardiovascular diseases are the leading cause of mortality and early assessment of carotid artery abnormalities with ultrasound is key for effective prevention. Obtaining the carotid diameter waveform is essential for hemodynamic parameter extraction. However, since it is not a trivial task to automate, compact computational models are needed to operate reliably in view of physiological variability.

Dynamic sub-array selection-based energy-efficient localization and tracking method to power implanted medical devices in scattering heterogenous media employing ultrasound.

Ultrasound (US) as a wireless power transfer methodology has drawn considerable attention from the implantable medical devices (IMD) research community. Beamforming (BF) using an external transducer array patch (ETAP) has been proposed as a robust localization scheme to find a mm-sized IMD inside the human body. However, for applications focusing on deep and shallow IMDs, optimum resource utilization at the ETAP is a major power efficiency concern for energy-constrained wearable patches.

Advancing the Local Pulse Wave Velocity Measurement-Wave Confluence Decomposition Using a Double Gaussian Propagation Model.

Background Pulse wave velocity (PWV) is a marker of arterial stiffness and local measurements could facilitate its widescale clinical use. However, confluence of incident and early reflected waves leads to biased spatiotemporal PWV estimates. Objective We introduce the Double Gaussian Propagation Model (DGPM) to measure local PWV in consideration of wave confluence (PWV[Formula: see text]) and compare it against conventional spatiotemporal PWV (PWV[Formula: see text]), with Bramwell-Hill PWV (PWV[Formula: see text]) and blood pressure (BP) as reference measures.

An electroluminescent and tunable cavity-enhanced carbon-nanotube-emitter in the telecom band.

Emerging photonic information processing systems require chip-level integration of controllable nanoscale light sources at telecommunication wavelengths. Currently, substantial challenges remain in the dynamic control of the sources, the low-loss integration into a photonic environment, and in the site-selective placement at desired positions on a chip. Here, we overcome these challenges using heterogeneous integration of electroluminescent (EL), semiconducting carbon nanotubes (sCNTs) into hybrid two dimensional - three dimensional (2D-3D) photonic circuits.

Ultrafast quantum key distribution using fully parallelized quantum channels.

The field of quantum information processing offers secure communication protected by the laws of quantum mechanics and is on the verge of finding wider application for the information transfer of sensitive data. To improve cost-efficiency, extensive research is being carried out on the various components required for high data throughput using quantum key distribution (QKD). Aiming for an application-oriented solution, we report the realization of a multichannel QKD system for plug-and-play high-bandwidth secure communication at telecom wavelengths.

Scaling waveguide-integrated superconducting nanowire single-photon detector solutions to large numbers of independent optical channels.

Superconducting nanowire single-photon detectors are an enabling technology for modern quantum information science and are gaining attractiveness for the most demanding photon counting tasks in other fields. Embedding such detectors in photonic integrated circuits enables additional counting capabilities through nanophotonic functionalization. Here, we show how a scalable number of waveguide-integrated superconducting nanowire single-photon detectors can be interfaced with independent fiber optic channels on the same chip.

Cryo-compatible opto-mechanical low-voltage phase-modulator integrated with superconducting single-photon detectors.

Photonic integrated circuits (PICs) have enabled novel functionality in quantum optics, quantum information processing and quantum communication. PICs based on Silicon Nitride (SiN) provide low-loss passive components and are compatible with efficient superconducting nanowire single-photon detectors (SNSPDs). For realizing functional quantum photonic systems, the integration with active phase-shifters is needed which is challenging at the cryogenic temperatures needed for operating SNSPDs.

Single-photon detection and cryogenic reconfigurability in lithium niobate nanophotonic circuits.

Lithium-Niobate-On-Insulator (LNOI) is emerging as a promising platform for integrated quantum photonic technologies because of its high second-order nonlinearity and compact waveguide footprint. Importantly, LNOI allows for creating electro-optically reconfigurable circuits, which can be efficiently operated at cryogenic temperature. Their integration with superconducting nanowire single-photon detectors (SNSPDs) paves the way for realizing scalable photonic devices for active manipulation and detection of quantum states of light.

Pulse Arrival Time Segmentation Into Cardiac and Vascular Intervals - Implications for Pulse Wave Velocity and Blood Pressure Estimation.

Objective: This study demonstrates a novel method for pulse arrival time (PAT) segmentation into cardiac isovolumic contraction (IVC) and vascular pulse transit time to approximate central pulse wave velocity (PWV).

Methods: 10 subjects (38 ± 10 years, 121 ± 12 mmHg SBP) ranging from normotension to hypertension were repeatedly measured at rest and with induced changes in blood pressure (BP), and thus PWV. ECG was recorded simultaneously with ultrasound-based carotid distension waveforms, a photoplethysmography-based peripheral waveform, noninvasive continuous and intermittent cuff BP.

Broadband Spectrometer with Single-Photon Sensitivity Exploiting Tailored Disorder.

Harnessing tailored disorder for broadband light scattering enables high-resolution signal analysis in nanophotonic spectrometers with a small device footprint. Multiple scattering events in the disordered medium enhance the effective path length which leads to increased resolution. Here we demonstrate an on-chip random spectrometer cointegrated with superconducting single-photon detectors suitable for photon-scarce environments.

Systolic Time Interval Estimation Using Continuous Wave Radar With On-Body Antennas.

Unlabelled: The estimation of systolic time intervals (STIs) is done using continuous wave (CW) radar at 2.45 GHz with an on-body antenna.

Motivation: In the state of the art, typically bioimpedance, heart sounds and/or ultrasound are used to measure STIs.