The damping of surface waves of small amplitude in liquid contained in cylinders has been calculated. Viscous dissipation in an assumed laminar boundary layer was taken to be the primary cause of damping. Experimental results were obtained for the logarithmic decrement as a function of the ratio of liquid height to cylinder radius for several water-filled cylinders. Theory and experiment were found to be in good agreement.

Reports that extremely low-frequency magnetic fields can interfere with normal biological cell function continue to stimulate experimental activity as well as investigations into the possible mechanism of the interaction. The "cyclotron resonance" model of Liboff has been tested by Smith et al. (Bioelectromagnetics 8, 215-227, 1987) using as the biological test system the diatom Amphora coffeiformis. They report enhanced motility of the diatom in response to a low-frequency electromagnetic field tuned to the cyclotron resonance condition for calcium ions. We report here an attempt to reproduce their results. Following their protocol diatoms were seeded onto agar plates containing varying amounts of calcium and exposed to colinear DC and AC magnetic fields tuned to the cyclotron resonant condition for frequencies of 16, 30, and 60 Hz. The fractional motility was compared with that of control plates seeded at the same time from the same culture. We find no evidence of a cyclotron resonance effect.

Low-level, steady electric fields of 6-10 volts/cm stimulated directional orientation and translocation of cultured human retinal pigment epithelial cells. The orientative movements (galvanotropism) consisted of somatic elongation of the cells into spindle shapes, followed by pivotal alignment orthogonal to the field. The anodal edges of the cells underwent retraction of their plasmalemmal extensions, while the cathode edges and the longitudinal ends developed lamellipodia and ruffled membranes. These tropic movements were followed by a translocational movement (galvanotaxis) of the cells towards the cathode. Staining of these migrating cells for actin showed the accumulation of stress fibers at the leading (cathodal) edge, as well as at the longitudinal ends of the elongated somata. These results suggest that endogenous, biologically-generated electric fields (eg., injury currents) may play a role in the guidance and migration of retinal pigment epithelial cells after retinal injury.

There are a number of reports of the plasma membrane transport of Ca2+ in biological systems being enhanced by low frequency electromagnetic fields (EMF), including reports that the enhancement involves a resonance-type response at the cyclotron frequency for Ca2+ ions for geomagnetic values of the magnetic field. Using the fluorescent probe fura2, we find no evidence for changes in cytosolic calcium concentration in BALB/c3T3, L929, V-79, and ROS, a rat osteosarcoma cell line, at the application of both resonant and nonresonant EMF.

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