Microwave-induced hearing: some preliminary theoretical observations

Pulsed microwaves impinging on the head of animals and man produce auditory sensations. Theoretical analyses indicate a series of resonant frequencies occurring inside the head. This is supported by previous observations of characteristic oscillations recorded from the round window of mammals during pulsed microwave irradiation.

Effects of prolonged quiescence on neuclei and chromatin of WI-38 fibroblasts

DNA synthesis and cell division are markedly reduced in confluent mono-layers of WI-38 diploid fibroblasts, but resume again if the depleted medium is replaced by fresh medium containing 10% fetal calf serum. If the cells are kept quiescent for prolonged periods of time after confluence (1 or 2 weeks), the fraction of cells that can be stimulated to proliferate by fresh serum decreases and the length of the prereplicative phase increases. The template activity of isolated nuclei decreases with increasing time of quiescence, and parallel changes occur in chromatin as evidenced by circular dichroism spectra and capacity to bind the intercalating dye, ethidium bromide. When WI-38 cells are stimulated to proliferate after prolonged quiescence, the increase in template activity of nuclei is delayed by several hours in comparison to cells stimulated after short periods of quiescence. Two distinct steps, both requiring serum, can be identified in the prereplicative phase of cells stimulated to proliferative after prolonged quiescence. We interpret the results as indicating that, during prolonged quiescence, WI-38 fibroblasts go into a deeper GO state from which they can be rescued only after prolonged stimulation. In this respect, prolonged quiescence may bear some resemblance to the process of aging.

Microwave auditory effect- a comparison of some possible transduction mechanisms

When human subjects are irradiated with pulse modulated microwave energy they report the perception of a sound that appears to originate from within or slightly behing the head. Three of the possible mechanisms are examined using first order mathematical approximations and several simplifying assumptions. The results show that while all three (radiation pressure, strictive force and thermal expansion) are capable of producing the phenomenon, the stress resulting from thermal expansion may be so great that it masks the effect of the others completely.

Coupling of Gaussian electromagnetic pulse into a muscle-bone model of biological structure

The effect of angle of incidence on the transmission electromagnetic pulse with Gaussion character in biological material is studied. The model assumed is a layer of soft tissue over a semi-infinite medium of boney structure governed by alpha dispersion. The numerical results demonstrate that the transmitted pulse strength is the greatest when the pulse is incident normally on the air-tissue interface. The coupling efficiency for a one microsecond pulse is three times as big as that for a ten microsecond pulse.

The ocular effects of microwaves on hypothermic rabbits: a study of microwave cataractogenic mechanisms

Rabbits, irradiated by known cataractogenic levels of 2.45 GHz radiation at 5 cm, did not develop cataracts if kept under general hypothermia. Radiation-induced temperature elevation appears to be essential for the cataractogenic effect of microwaves.

Nucleic acid metabolism during cytokinin induced cellular differentiation

Edstrom's microphoresis technique has been employed to determine the quantitative alterations in nucleic acid content and base composition of individual cells associated with the initiation of bud primordia in Funaria hygrometrica. The filamentous protonema of this moss initiates bud cells which through repeated divisions form the leafy gametophores. The cytokinin, 6-furfurylaminopurine (kinetin), was used to induce the differentiation of bud cells from protonematal cells. The total RNA content of kinetin-induced bud cells (22.0 mumug/cell) was nearly 15 times that of protonematal cells (1.6 mumug/cell). The same dramatic increase in total RNA was apparent in bud cells which developed spontaneously in older cultures. As would be predicted, the adenine (A) to guanine (G) ratio for DNA from bud and protonematal cells was identical (0.7). The A:G ratio for RNA from bud cells (1.0) was much lower than that from protonematal cells (1.7). Thus, kinetin-induced differentiation in this system involves a dramatic increase in total RNA, the base composition of which approaches that of DNA. The base composition (A:G ratio) of DNA remains constant.