Design and testing of a system for measuring high-frequency AC losses in superconducting wires and coils carrying DC and AC currents.

Development of high-power superconducting applications requires the accurate estimation of AC losses in the superconductor. In applications such as superconducting magnetic energy storage, the charge/discharge/persistent switching frequency of the coil, resulting from pulse width modulation control algorithms, is usually in the kilohertz regime. Therefore, a thorough investigation of the losses in the kilohertz regime of AC currents superimposed on large DC currents is essential in order to ensure the device stable operation at a predefined temperature.

Meshing complex macro-scale objects into self-assembling bricks.

Self-assembly provides an information-economical route to the fabrication of objects at virtually all scales. However, there is no known algorithm to program self-assembly in macro-scale, solid, complex 3D objects. Here such an algorithm is described, which is inspired by the molecular assembly of DNA, and based on bricks designed by tetrahedral meshing of arbitrary objects.

Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation.

Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation.

Magnetic stimulation intensity modulates motor inhibition.

Repetitive transcranial magnetic stimulation (rTMS) is a standard tool in neuroscience research and therapy. Here we study one rTMS property that has not received adequate attention, the interaction of subthreshold intensity stimulation and low frequencies. We applied 1Hz rTMS over the motor cortex at three intensities, 40%, 80% and 100% of the resting motor threshold (rMT), and measured cortical excitability before and after the stimulation sessions.

Mechanisms of magnetic stimulation of central nervous system neurons.

Transcranial magnetic stimulation (TMS) is a stimulation method in which a magnetic coil generates a magnetic field in an area of interest in the brain. This magnetic field induces an electric field that modulates neuronal activity. The spatial distribution of the induced electric field is determined by the geometry and location of the coil relative to the brain.