N. Convers Wyeth

Are membrane microwave effects related to a critical phase transition

We present a model that can explain reported nonthermal effects in biological membranes that occur when they are exposed to very low intensity electromagnetic fields in the microwave portion of the spectrum. One argument is that the external field drives the membrane closer to a critical point, and that critical fluctuations begin to dominate the behavior of the system. In an alternative argument, the membrane is initially close enough to its critical point for the system to be highly susceptible to specific external perturbations. Thus continuous, i.e., critical, phase transitions serve to mediate the field–membrane coupling via the greatly enhanced susceptibility of the system when it is near its critical point. We also discuss a specific example related to the experimentally observed anomaly in passive sodium ion permeability at the phase transition in the erythrocyte membrane when exposed to microwaves, and we propose additional experiments that will serve to test our hypotheses.

Laser interferometer for measuring microwave‐induced motion in eye lenses in vitro

A system was designed to optically measure the physical motion induced by a microwave pulse on a rat eye lens immersed in saline. After consideration of several possible techniques, a Michelson interferometer using a HeNe laser and normal reflection from the lens surface was constructed. The system uses wavefronts matched to the curved lens surface, a vibrating reference mirror for calibration and signal discrimination, a sample chamber mechanically isolated from the microwave waveguide, and a fast photodetector and signal averager. A rotatable half‐wave plate and two polarizers were used to smoothly vary the intensity of the reference beam while maintaining the spatial integrity of its wavefronts. The system was able to measure motion down to 2 nm and performed successfully in the microwave pulse exposure experiments.

Membranes, Electromagnetic Fields and Critical Phenomena

Highly complex systems are often endowed with characteristics that apparently bear little or no relationship to the properties of the parts that comprise the system. These collective properties are sometimes called “emergent” properties (Anderson, 1984). Such systems can often exist in different thermodynamic states or phases and can undergo transitions between these various states. When the inherent symmetry properties of the various states are different and the system undergoes a transition between two such states, the phenomenon is usually described as a symmetry-breaking transition. One very interesting property of certain symmetry-breaking transitions is that when they are occurring or are “about” to occur, the system often possesses an unusually high degree of sensitivity to external perturbations (Wilson, 1979).

Alterations in Electrical Double Layer Structure Due to Electromagnetic Coupling to Membrane Bound Enzymes

We shall discuss the role that the electrical double layer formed at the interface of a charged biological membrane and the membrane’s extracellular ionic environment might play in gaining an understanding of how time-varying electromagnetic fields of very low intensity interact with the membrane per se. The analysis we shall present originated in an effort to explain what have generally become known as nonthermal interactions; that is coupling between an external field and the biological system of interest that cannot be attributed to the thermalization of the energy carried by the field. Alternatively such responses cannot be elicited by simple heating processes, for example via some other experimental means of heating.

Simple numerical analysis of null‐point calorimeter data

Null‐point calorimeters provide the equivalent surface temperature data for a slab exposed to a time‐varying flux. A simple method to calculate the absorbed flux as a function of time using such temperature versus time data is presented. The method involves numerical evaluation of a convolution integral of the first time derivative of the temperature and a function defined by an infinite sum. The temperature derivative is calculated using a least‐squares‐fitting algorithm, and the infinite sum using a close analytic approximation. The method is applied to two sets of actual null‐point calorimeter data, and the calculated flux is in excellent agreement with data obtained by other means.