Ronald L. Seaman

Hyperactivity caused by a nitric oxide synthase inhibitor is countered by ultra‐wideband pulses

Potential action of ultra-wideband (UWB) electromagnetic field pulses on effects of N(G)-nitro- L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase (NOS), on nociception and locomotor activity was investigated in CF-1 mice. Animals were injected IP with saline or 50 mg/kg L-NAME and exposed for 30 min to no pulses (sham exposure) or UWB pulses with electric field parameters of 102+/-1 kV/m peak amplitude, 0.90+/-0.05 ns duration, and 160+/-5 ps rise time (mean+/-S.D.) at 600/s. Animals were tested for thermal nociceptive responses on a 50 degrees C surface and for spontaneous locomotor activity for 5 min. L-NAME by itself increased mean first-response (paw lift, shake, or lick; jump) and back-paw-lick response latencies and mean locomotor activity. Exposure to UWB pulses reduced the L-NAME-induced increase in back-paw-lick latency by 22%, but this change was not statistically significant. The L-NAME-induced hyperactivity was not present after UWB exposure. Reduction and cancellation of effects of L-NAME suggest activation of opposing mechanism(s) by the UWB pulses, possibly including increase of nitric oxide production by NOS. The action, or actions, of UWB pulses appears to be more effective on locomotor activity than on thermal nociception in CF-1 mice.

Applications of robots in rehabilitation

Abstract The ability to manipulate objects in our environments is an important human characteristic. The use of a single multipurpose device, such as a robot, offers significant advantages over a variety of assistive devices and tools. This article supports the use of robots by disabled persons and rehabilitation applications of robots. Vocational applications and independent living applications are featured. Independent living uses of robots which have actually been implemented cover a wide variety of daily living tasks. Although most uses of robots in rehabilitation environments consists of robots designed for other uses (e.g. industrial, educational), some development projects have been undertaken and are also presented here. The technological issues (e.g. sensors, end effectors, and alternative human control of robots) and nontechnological issues (e.g. cost effectiveness, acceptance, and safety) which affect the design, development, modification, and use of robots in rehabilitation are also reviewed.

Ultra-wideband electromagnetic pulses and morphine-induced changes in nociception and activity in mice

Mice were exposed to ultra-wideband (UWB) electromagnetic pulses averaging 99-105 kV/m peak amplitude, 0.97-1.03 ns duration, and 155-174 ps rise time, after intraperitoneal administration of saline or morphine sulfate. They were then tested for thermal nociception on a 50 degrees C surface and for spontaneous locomotor activity and its time profile over 5 min. Analysis of results showed no effect of UWB exposure on nociception and activity measures in CF-1 mice after 15-, 30-, or 45-min exposure to pulses at 600/s or after 30-min exposure to UWB pulses at 60/s. Similarly, no effect was seen in C57BL/6 mice after 30-min exposure to pulses at 60/s or 600/s. Although trends in morphine-modified measures seen with UWB pulse repetition frequency could be expected because of increased levels of low-frequency energy, no significant change was seen in normal or morphine-modified nociception or activity after UWB exposure. This indicated lack of effect of the UWB pulses used in these experiments on nervous system components, including endogenous opioids, involved in these behaviors.

Auditory unit responses to single-pulse and twin-pulse microwave stimuli

Responses of units in the cat cochlear nucleus to single microwave pulses with different durations and to twin microwave pulses with different interpulse delays are used to study microwave hearing. Inferred threshold specific absorption rate is less than 6 mW/g; inferred threshold specific absorption, less than 0.5 microJ/g. The existence of responses from units with characteristic frequencies (CFs) from 931 Hz to 25.5 kHz is not consistent with a primary role for head resonance in microwave hearing. Patterns of response amplitude have a periodicity of 1/CF and are fully explained by frequency content of the pulse stimulus and signal processing of the auditory system. For pulses shorter than about 0.24/CF, it is shown that response amplitude is predictably proportional to pulse energy.

Pulsed microwave induced bioeffects

High-power pulsed microwave radiation, when applied to solutions containing dissolved carbon dioxide (or bicarbonate), hydrogen peroxide, and the soluble organic semi-conductor diazoluminomelanin, generates sound, pulsed luminescence, and electrical discharge. Microbes exposed to these phenomena experienced damage comparable to short-time, high-temperature insults, even though the average and measurable localized temperatures were insufficient to cause the observed effects.

Method to record evoked potentials from the frog eighth nerve.

A method for recording evoked potentials from the eighth nerve of frogs is described. A prominent bipolar wave with latency of 3-6 ms recorded in response to auditory stimuli in Rana catesbeiana is attributable to eighth-nerve activity. The evoked potential provides an integrated response for study of inner ear and peripheral neural activity which complements responses obtained by other recording methods.

Directed killing of anthrax spores by microwave-induced cavitation

High-power pulsed-microwave radiation damages anthrax spores by apparent sonoluminescence in aqueous solutions containing the organic semiconductor diazoluminomelanin (DALM). DALM biosynthesized by JM109 E. coli, containing the plasmid pIC2ORNR/sub 1.1/, had a higher affinity for spores of Sterne strain anthrax when compared to several other species of bacilli and enhanced the effect. Upon exposure to pulsed-microwave radiation, anthrax spores showed a maximum of 4 to 5 (i.e., 4.6) logs of kill. The light emitted was typical of plasma gas emissions and the spores, upon scanning electron-microscopic examination, showed enlargement and rupture typical of rapid expansion. Therefore, microwave-induced cavitations localized to the spore surfaces enhanced kill.

PULSED MICROWAVE INDUCED LIGHT, SOUND, AND ELECTRICAL DISCHARGE ENHANCED BY A BIOPOLYMER

Intense flashes of light were observed in sodium bicarbonate and hydrogen peroxide solutions when they were exposed to pulsed microwave radiation, and the response was greatly enhanced by a microwave-absorbing, biosynthesized polymer, diazoluminomelanin. A FPS-7B radar transmitter, operating at 1.25 GHz provided pulses of 5.73 +/- 0.09 micros in duration at 10.00 +/- 0.03 pulses/s with 2.07 +/- 0.08 MW forward power (mean +/- standard deviation), induced the effect but only when the appropriate chemical interaction was present. This phenomenon involves acoustic wave generation, bubble formation, pulsed luminescence, ionized gas ejection, and electrical discharge. The use of pulsed microwave radiation to generate highly focused energy deposition opens up the possibility of a variety of biomedical applications, including targeting killing of microbes or eukaryotic cells. The full range of microwave intensities and frequencies that induce these effects has yet to be explored and, therefore, the health and safety implications of generating the phenomena in living tissues remain an open question.

Modification of acoustic and tactile startle by single microwave pulses

Single microwave pulses at 1.25 GHz were delivered to the head and neck of male Long-Evans rats as a prestimulus to acoustic and tactile startle. For acoustic startle, pulses averaging 0.96 microsecond in duration were tested with two specific absorption rate (specific absorption) ranges, 15.0-30.0 kW/kg (16.0-44.2 mJ/kg) and 35.5-86.0 kW/kg (66.6-141.8 mJ/kg), delivered 201, 101, 51, 3, and 1 ms before and 1 ms after onset of a startling noise. The low-intensity pulse did not affect peak amplitude, integral, or latency of the whole-body startle response. The high-intensity pulse at 101 and 51 ms inhibited the startle response by decreasing peak amplitude and integral; at 201 and 51 ms latency was increased. The high-intensity pulse at 1 ms enhanced the startle response by increasing peak amplitude and at 3 ms by increasing integral. For tactile startle, either microwave pulses averaging 7.82 microseconds in duration and 55.9-113.3 kW/kg (525.0-1055.7 mJ/kg) or 94 dB SPL clicks were delivered 157, 107, 57, and 7 ms before and 43 ms after onset of a startling air burst. The microwave pulse at 57 ms inhibited the startle response by decreasing peak amplitude; at 157, 107, 57, and 7 ms it increased latency. The microwave pulse at 43 ms after onset enhanced the startle response by increasing peak amplitude. The acoustic click at 157 and 57 ms inhibited the startle response by decreasing peak amplitude; at 157,2 107, and 57 ms it increased latency.(ABSTRACT TRUNCATED AT 250 WORDS)

CW microwave fields evoke body movements in bilaterally cochleotomized rats

The probability of a whole-body movement in rats exposed to one second microwave pulses is a function of power. This functional relationship is similar in deafened and hearing rats, which eliminates microwave hearing as a possible mechanism for the effect. Observed thermal gradients in the facial skin support the hypothesis that tactile sensations are the eliciting stimulus for the whole-body movement, but do not address the hypothesis that microwave fields exert a direct effect on the central nervous system to cause the movement.