Biomedical subjects

M Dawber

Publications and source records attributed to M Dawber.

3 recordsLinked to original sources

PubMed2005

Unusual behavior of the ferroelectric polarization in PbTiO3/SrTiO3 superlattices.

Artificial PbTiO3/SrTiO3 superlattices were constructed using off-axis rf magnetron sputtering. X-ray diffraction and piezoelectric atomic force microscopy were used to study the evolution of the ferroelectric polarization as the ratio of PbTiO3 to SrTiO3 was changed. For PbTiO3 layer thicknesses larger than the 3-unit cell SrTiO3 thickness used in the structure, the polarization is found to be reduced as the thickness is decreased. This observation confirms the primary role of the depolarization field in the polarization reduction in thin films. For the samples with ratios of PbTiO3 to SrTiO3 of less than one, a surprising recovery of ferroelectricity that cannot be explained by electrostatic considerations was observed.

Journal Article↗

PubMed1977

A new anorexigen assay: stress-induced hyperphagia in rats.

Humans often respond to stress by overeating. A rat model of hyperphagia induced by a stressful tail-pinch has been described. Consumption of sweetened condensed milk by vaive rats was measured durin the stress. This milk drinking was prevented by pretreatment with d-amphetamine, chlorphentermine, diethylpropion, fenfluramine, methamphetamine, morphine, chlorpromazine and haloperidol. The benzodiazepines chlordiazepoxide and diazepam increased the hyperphagia. The relevance of dopaminergic agonistic and antagonist activities to anorexigenic activity are questioned.

Analgesics↗

PubMedDate not supplied

Cat sleep: a unique first night effect.

Longitudinal sleep studies in chronically implanted cats revealed a unique first night effect. Unlike other species, during the first 24 hr of sleep recording, the electroencephalogram and reticular formation multiple unit activity revealed more rapid eye movement sleep occurred than during subsequent 24 hr recording sessions. In addition, higher rapid eye movement to slow wave sleep ratios were observed for the first 24 hr as compared to the following days. An increase in wakefulness and decrease in slow wave sleep occurred on the third recording day as compared to the initial 24 hr period. These data have important implications for studies of variables on the sleep pattern of animals.

Animals↗