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During the past five years a study has been made of the electrical properties of human skin in vivo both experimentally and theoretically, seeking to make a coherent whole out of the very diverse phenomenology reported in the very scattered literature. A Fourier transform method was used, employing novel electronic techniques and four non-invasive electrodes on the subject to separately determine the properties of the stratum corneum and the deeper tissues. Both linear and non-linear, A.C. and D.C. properties were investigated in this way, and the wide perspective obtained has made it possible to re-interpret the findings of previous workers and so assemble a self-consistent model of nearly all the known electrical properties of human skin. The main conclusions of this work are that: (a) The small-signal A.C. impedance properties of skin are extremely well fitted by a minor arc of a circle on the complex impedance plane, and the depression of the centre of the circle below the equivalent series resistance axis is very significantly greater in psoriatic skin and in hyper-hydrated normal skin. (b) This behaviour cannot be adequately interpreted by any extant physical model of skin, but can be adequately interpreted by considering the stratum corneum to be an inhomogeneous or amorphous semiconductor. (c) The semiconductivity of human skin has been demonstrated both in vitro and in vivo, and was found to have activation enthalpies averaging 0.46 eV (10.63 kcal/mole). (d) These insights into the mechanisms of electrical charge transport through skin may suggest new ways of characterizing the properties of skin using methods developed for the semiconductor industry. (e) The results in the literature of "phoreography" should be re-interpreted, with much greater emphasis being placed on the properties of the skin appendages.

Walking leg closer muscle neuromuscular parameters were recorded electrophysiologically from homothermally and heterothermally acclimated Carcinus maenas (eurythermic) and Cancer pagurus (stenothermic). Homothermal (and immobilised) crabs of both species were acclimated to either 8 C or 22 C, whereas heterothermally acclimated crabs were acclimated to 8 C and 22 C coincidentally, exposing the animal's central nervous system (CNS) to either the warm (22 C) or cold (8 C) acclimation temperature. Thus, heterothermal acclimation exposes the CNS/endocrine system and one set of walking legs at one acclimation temperature, the contralateral walking legs are acclimated to the other acclimation temperature. This allowed an investigation into the CNS influence on the attainment of acclimation by walking legs. Comparisons of acclimation responses of the neuromuscular function of isolated walking legs from the same animal were done with respect to the walking leg and CNS acclimation temperatures experienced. Animals were acclimated for two weeks, recordings were taken of excitatory junctional potentials (EJP) etc., from dactylopodite closer muscle fibres when stimulated by the tonic motor axon over an experimental temperature range (6-26 C).The acclimation responses in homothermally exposed crabs of both species resulted in partial (Precht, type III) responses in resting potential, single and double pulse stimulated excitatory junctional potential amplitudes, these were interpreted as responses that allowed the maintenance of muscle function in the new thermal condition. With respect to long term thermal acclimation other electrophysiological parameters gave equivocal compensatory responses. Capacity acclimation responses were more complete in C.pagurus than C.maenas. In heterothermally acclimated animals resting potentials and EJP amplitudes revealed partial acclimation responses in a compensatory manner. Acclimation of heterothermally acclimated C.maenas and C.pagurus was determined to be independent of a CNS influence, indicating thermal acclimation was in response to the local tissue acclimation temperature.

A new method for the estimation of the EEG evoked potential (EP) is presented in this thesis. This method is based on a new model of the EEG response which is assumed to be the sum of the EP and independent correlated Gaussian noise representing the spontaneous EEG activity. The EP is assumed to vary in both shape and latency, with the shape variation represented by correlated Gaussian noise which is modulated by the EP. The latency of the EP is also assumed to vary over the ensemble of responses in a random manner governed by some unspecified probability density. No assumption on stationarity is needed for the noise. / With the model described in state-space form, a Kalman filter is constructed, and the variance of the innovation process of the response measurements is derived. A maximum likelihood solution to the EP estimation problem is then obtained via this innovation process. / Tests using simulated responses show that the method is effective in estimating the EP signal at signal-to-noise ratio as low as -6db. Other tests using real normal visual response data yield reasonably consistent EP estimates whose main components are narrower and larger than the ensemble average. In addition, the likelihood function obtained by our method can be used as a discriminant between normal and abnormal responses, and it requires smaller ensembles than other methods.

Thesis (Masters by Research) - Swinburne University of Technology, Brain Sciences Institute, 1999. / "A thesis submitted of the requirement for the award of the degree Masters by Research, Brain Sciences Institute - 1999. Typescript. Includes bibliographical references (p. 141-164).

Thesis--University of Alabama. / Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1951. / Typescript with manuscript equations. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 34).

Thesis (Ph. D.)--Duke University, 2008.