No abstract

In the larynx, spectral differences appear to exist between normal tissue, carcinoma, and papilloma. The ability to obtain spectra rapidly supports potential for future in vivo studies.

Understanding the relationship between brain activity and specific mental function is important for medical diagnosis of brain symptoms, such as epilepsy. Magnetoencephalography (MEG), which uses an array of high-sensitivity magnetometers to record magnetic field signals generated from neural currents occurring naturally in the brain, is a noninvasive method for locating the brain activities. The MEG is normally performed in a magnetically shielded room. Here, we introduce an unshielded MEG system based on optically pumped atomic magnetometers. We build an atomic magnetic gradiometer, together with feedback methods, to reduce the environment magnetic field noise. We successfully observe the alpha rhythm signals related to closed eyes and clear auditory evoked field signals in unshielded Earth’s field. Combined with improvements in the miniaturization of the atomic magnetometer, our method is promising to realize a practical wearable and movable unshielded MEG system and bring new insights into medical diagnosis of brain symptoms.

No abstract

The static conductivity and dielectric constant of two-component periodic composite material are calculated using the Fourier expansion technique. The composite material consists of spheres that are arranged in simple, face-centered, or body-centered cubic lattices. The spheres may be isolated to yield high porosity or pore space, or they may intercept each other, leaving small pore space in between. The effective static conductivity and dielectric constant of such structures are computed theoretically when the pore space is filled with a material that has a conductivity or dielectric constant which differs from that of the matrix of the structure.