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Biomedical subjects

T Holden

Publications and source records attributed to T Holden.

12 recordsLinked to original sources
PubMed2004

In-plane spectral weight shift of charge carriers in YBa2Cu3O6.9.

The temperature-dependent redistribution of the spectral weight of the CuO2 plane-derived conduction band of the YBa2Cu3O6.9 high-temperature superconductor (superconducting transition temperature = 92.7 kelvin) was studied with wide-band (0.01- to 5.6-electron volt) spectroscopic ellipsometry. A superconductivity-induced transfer of the spectral weight involving a high-energy scale in excess of 1 electron volt was observed. Correspondingly, the charge carrier spectral weight was shown to decrease in the superconducting state. The ellipsometric data also provide detailed information about the evolution of the optical self-energy in the normal and superconducting states.

Journal Article↗
PubMed2002

Josephson plasma resonance and phonon anomalies in trilayer Bi2Sr2Ca2Cu3O10.

The far-infrared (FIR) c axis conductivity of a Bi2223 crystal has been measured by ellipsometry. Below T(c) a strong absorption band develops near 500 cm(-1), corresponding to a transverse Josephson plasmon. The related increase in FIR spectral weight leads to a giant violation of the Ferrell-Glover-Tinkham sum rule. The gain in c axis kinetic energy accounts for a sizable part of the condensation energy. We also observe phonon anomalies which suggest that the Josephson currents lead to a drastic variation of the local electric field within the block of closely spaced CuO2 planes.

Journal Article↗
PubMed1997

Effects of nicotine dose and administration method on withdrawal symptoms and side effects during short-term smoking abstinence.

The effects of using several nicotine replacement treatments on self-reported withdrawal symptoms and side effects during 2-day periods of smoking cessation, with 5 days of ad lib smoking between cessation days, were evaluated. Participants (N = 18) experienced the following conditions: nicotine gum, 24-hr patch, 16-hr patch, 24-hr patch plus gum, double 24-hr patch, and no nicotine replacement. The present study found morning urge to smoke was greater during the 16-hr than during the 24-hr patch condition. Double-patch use resulted in significantly greater insomnia than the smoking baseline and 16-hr patch conditions. The no medication and gum alone conditions resulted in similar withdrawal symptoms, and both tended to result in greater reported withdrawal symptoms than the smoking baseline condition. There were no significant withdrawal symptom differences between the 24-hr, patch-gum, and double-patch conditions. The 24-hr and double-patch conditions were preferred by two thirds of the participants (6 each).

Administration, Cutaneous↗
PubMed1987

Non-compliance with psychotropic medication.

A 2-year follow-up study of 406 patients discharged from a psychiatric hospital revealed that non-compliance with psychotropic medication was a problem in at least half the cases overall. Non-compliance with oral phenothiazine was particularly evident among the cohorts of patients classified as black and coloured (approximately two-thirds and half respectively failing to comply, compared with approximately one-quarter in the white cohort). Compliance was somewhat better for intramuscular medication. The proportion of poor compliers remained at about the same level at the 6-month, 18-month and 24-month follow-ups. There were more male than female non-compliers (51% and 41% respectively) and more among younger patients of all population groups. Understanding of the details of treatment by the relatives of black and coloured patients was particularly poor, only 14% and 12% respectively understanding the purpose and nature of medication. The main reasons for non-compliance were active resistance to taking medication, unpleasant side-effects and non-attendance at clinics. Several areas which allow remediation of the problem have been highlighted.

Black or African American↗
PubMed1986

Parkinsonian symptoms in tardive dyskinesia. A prevalence study.

Of 49 unselected patients with tardive dyskinesia (TD) 28 (57%) exhibited various parkinsonian signs. Isolated tremor was encountered in 11 patients, tremor with hypokinesia and rigidity in 13 patients, and hypokinesia and rigidity alone in 4. Tremor was detected among patients with scorable peripheral signs of TD. Hypokineto-rigidity, with or without tremor, was attributed to high doses of neuroleptics--notably fluphenazine. This study confirmed reports that isolated parkinsonian signs occurring concurrently with TD must be considered a regular phenomenon even when questionable cases (e.g. tremor in lithium-treated patients, action-tremor in the elderly) are disregarded. However, given the 'fragmentation' of the parkinsonian syndrome, often atypical tremor and signs of anosognosia in TD patients, the final diagnosis may necessitate pharmacological testing (discontinuation of neuroleptic medication, administration of anticholinergics).

Aged↗
PubMed1985

Cognitive impairment in patients with tardive dyskinesia.

Schizophrenic patients with (N = 17) and without (N = 14) tardive dyskinesia performed several neuropsychological tests. Most patients (88%) showed complete lack of concern or anosognosia with regard to their involuntary movement. A marginally significant difference was found in recall of pictures presented in the right hemispace. It is suggested that when patients with organic brain disorder and a low Mini-Mental State score are excluded, neuropsychological tests do not differentiate between tardive dyskinesia patients and nonhyperkinetic controls. The results are discussed in relation to hemispheric asymmetries in schizophrenia.

Aged↗