Marcel H.H. Weusthof

Barbed channels enhance unidirectional connectivity between neuronal networks cultured on multi electrode arrays

Cultured neurons on multi electrode arrays (MEAs) have been widely used to study various aspects of neuronal (network) functioning. A possible drawback of this approach is the lack of structure in these networks. At the single cell level, several solutions have been proposed to enable directed connectivity, and promising results were obtained. At the level of connected sub-populations, a few attempts have been made with promising results. First assessment of the designs functionality, however, suggested room for further improvement. We designed a two chamber MEA aiming to create a unidirectional connection between the networks in both chambers (“emitting” and “receiving”). To achieve this unidirectionality, all interconnecting channels contained barbs that hindered axon growth in the opposite direction (from receiving to emitting chamber). Visual inspection showed that axons predominantly grew through the channels in the promoted direction. This observation was confirmed by spontaneous activity recordings. Cross-correlation between the signals from two electrodes inside the channels suggested signal propagation at ≈2 m/s from emitting to receiving chamber. Cross-correlation between the firing patterns in both chambers indicated that most correlated activity was initiated in the emitting chamber, which was also reflected by a significantly lower fraction of partial bursts (i.e., a one-chamber-only burst) in the emitting chamber. Finally, electrical stimulation in the emitting chamber induced a fast response in that chamber, and a slower response in the receiving chamber. Stimulation in the receiving chamber evoked a fast response in that chamber, but no response in the emitting chamber. These results confirm the predominantly unidirectional nature of the connecting channels from emitting to receiving chamber.

A Full Body Sensing System for Monitoring Stroke Patients in a Home Environment

Currently, the changes in functional capacity and performance of stroke patients after returning home from a rehabilitation hospital is unknown to a physician, having no objective information about the intensity and quality of a patient’s daily-life activities. Therefore, there is a need to develop and validate an unobtrusive and modular system for objectively monitoring the stroke patient’s upper and lower extremity motor function in daily-life activities and in home training. This is the main goal of the European FP7 project named “INTERACTION”. A complete full body sensing system is developed, whicj integrates Inertial Measurement Units (IMU), Knitted Piezoresistive Fabric (KPF) strain sensors, KPF goniometers, EMG electrodes and force sensors into a modular sensor suit designed for stroke patients. In this paper, we describe the complete INTERACTION sensor system. Data from the sensors are captured wirelessly by a software application and stored in a remote secure database for later access and processing via portal technology. Data processing includes a 3D full body reconstruction by means of the Xsens MoCap Engine, providing position and orientation of each body segment (poses). In collaboration with clinicians and engineers, clinical assessment measures were defined and the question of how to present the data on the web portal was addressed. The complete sensing system is fully implemented and is currently being validated. Patients measurements start in June 2014.

A new test generation approach for embedded analogue cores in SoC

This paper proposes a new test-generation approach for embedded analogue cores in SoC. The key features of this approach are the developed testability-analysis based multifrequency test pattern generation method, the novel PID feedback-based test signal backtrace procedure and the fast tolerance-box propagation algorithm. Moreover, possible DFT solutions are discussed. Finally, this approach has been validated by experiments conducted on a real hardware implementation.

Application of DfT techniques to a 20 GHz superconductor delta ADC

Advances in the mobile communication industry require very high-speed ADCs for their implementation. In the near future, state-of-the-art semiconductor ADCs cannot fulfill the requirements in frequency and resolution. Superconductor technology is promising for the implementation of this application. The testing of these converters is difficult, as usually extremely high performance instruments are required. In addition, the interfacing between device and signal generation/test equipment is very critical. Following the current trend of test-resource partitioning, our basic approach has been to reduce or omit the interfacing at high speeds and effectively down-rating the required test equipment. We have adapted existing DfT techniques to the superconductor technology. In its ultimate form it could result in built-in-self-test.

A System for Monitoring Stroke Patients in a Home Environment

Currently, the changes of functional capacity and performance of stroke patients after returning home from a rehabilitation hospital is unknown for a physician, having no objective information about the intensity and quality of a patients daily-life activities. Therefore, there is a need to develop and validate an unobtrusive and modular system for objectively monitoring the stroke patients upper and lower extremity motor function in daily-life activities and in home training. This is the main goal of the European FP7 project named âx80x9cINTERACTIONâx80x9d. A complete sensing system is developed, whereby Inertial Measurement Units (IMU), Knitted Piezoresistive Fabric (KPF) goniometers, KPF strain sensors, EMG electrodes and force sensors are integrated into a modular sensor suit designed for stroke patients. In this paper, we describe the systems architecture. Data from the sensors are captured wirelessly and stored in a remote secure database for later access and processing via portal technology. In collaboration with clinicians and engineers, clinical outcome measures were defined and the question of how to present the data on the web portal was addressed. The first implementation of the complete system includes a basic version of all components and is currently being extended to include all sensors within the INTERACTION system.