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Biomedical subjects

S Chapman

Publications and source records attributed to S Chapman.

At least 199 records · Page 11Linked to original sources
PubMed1997

Experimental simulation of the thrust phases of fast-start swimming of fish

Measurements of the thrust and forward impulse of a simulated fish tail and mathematical modeling indicate that the propulsive forces of fast-start swimming can be optimized by three different effects: (i) exactly inverting the tail tip vortex that is generated with the initial stroke, (ii) using a moderately flexible tail, and (iii) introducing a specific delay between the initial stroke and the return stroke. Experiments were performed with a new computer-controlled fish-tail simulation apparatus, and the results confirm the theoretical predictions of a previous study.

Journal Article↗
PubMed1997

Do work-place smoking bans cause smokers to smoke "harder"? Results from a naturalistic observational study.

The purpose of this study was to investigate whether smokers outside buildings with work-place smoking bans smoke "harder" than those smoking in social settings. An unobtrusive random observational study of smokers followed by structured interview was used, with 143 smokers taking smoking breaks outside their office buildings and 113 smokers in social settings. The main outcome measurements were number of puffs per cigarette and cigarette smoking duration. The mean number of puffs per cigarette for the office building group was 18.7% greater than that for the social settings group (10.7 +/- 3.2 vs. 8.7 +/- 2.7, t = 5.58, df = 253, p < 0.001); 74.8% of smokers outside offices took more than the mean number of puffs for the group compared to 42.5% of smokers in social settings (chi 2 df 1 = 26.31, p < 0.0001). Mean cigarette smoking duration was 30.4% shorter for the work-place group than the social settings group (3.9 +/- 1.2 minutes vs. 5.6 +/- 2.6 minutes). Of smokers outside offices, 55.2% had a cigarette smoking duration between 3 and 4.59 minutes, while 53.1% of smokers in social settings took > or = 5 minutes to smoke the observed cigarette (chi 2 df 2 = 31.55, p < 0.0001). Smokers who scored at the 75th percentile on the Fagerstrom Tolerance Scale took a mean 9.5 +/- 2.6 puffs per cigarette compared to 9.3 +/- 2.7 puffs by those who scored in the 25th percentile on the scale (t = 0.34, df = 145, p = 0.73). Regardless of degree of nicotine dependency, smokers leaving work-stations to smoke outside buildings smoked their cigarettes nearly 19% "harder" than cigarettes smoked in social settings. The individual and public health benefits of reduced smoking frequency engendered by work-place smoking bans may be lessened by policies which allow smokers to take smoking breaks.

Adult↗
PubMed1996

Is the ratio of inhaled corticosteroid to bronchodilator a good indicator of the quality of asthma prescribing? Cross sectional study linking prescribing data to data on admissions.

OBJECTIVE: To investigate the ratio of inhaled corticosteroid to bronchodilator as a measure of the quality of asthma prescribing by general practitioners. DESIGN: Ecological cross sectional study linking general practitioner asthma prescribing with hospital admission data and a measure of deprivation. SUBJECTS: 11 family health services authorities in the West Midlands region and 99 general practices in North Staffordshire. MAIN OUTCOME MEASURES: Hospital admission rates for asthma; the ratio of inhaled corticosteroid to bronchodilator; and Townsend deprivation scores. RESULTS: No overall significant correlation was found between admission rates for asthma and corticosteroid:bronchodilator ratios for family health services authorities (Spearman's rs = -0.109, P = 0.750) or general practices (rs = -0.084, P = 0.407). In deprived family health services authority areas and general practices an inverse non-significant correlation existed between admission rates for asthma and corticosteroid:bronchodilator ratios (rs = -0.300, P = 0.624; rs = -0.218, P = 0.136). In contrast, in more affluent areas and general practices a positive non-significant correlation existed between admission rates and corticosteroid:bronchodilator ratios (rs = 0.371, P = 0.468; rs = 0.038, P = 0.792). CONCLUSION: Although the corticosteroid:bronchodilator ratio may be a valid indicator of the quality of prescribing for individual patients with asthma, caution should be applied in interpreting aggregated ratios. Differences in the severity of asthma or the prevalence of chronic obstructive pulmonary disease may explain inconsistent associations between admission rates for asthma and corticosteroid:bronchodilator ratios in family health services authorities and general practices with different deprivation scores.

Administration, Inhalation↗
PubMed1996

Managing HIV. Part 7: Professional issues. 7.6 Legal issues in HIV medicine.

The mortality, stigma and publicity surrounding HIV/AIDS have brought into focus many legal and ethical issues arising in the practice of medicine. Three important aspects of the practice of HIV medicine are the obligation to notify health authorities of HIV diagnoses, special obligations to inform and counsel patients who have or may have HIV and the duty of confidentiality.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Tobacco control.

Explore the source record for details and available documents.

Adolescent↗
PubMed1996

Assembly and movement of a plant virus carrying a green fluorescent protein overcoat.

Potato virus X (PVX) is a filamentous plant virus infecting many members of the family Solanaceae. A modified form of PVX, PVX.GFP-CP which expressed a chimeric gene encoding a fusion between the 27-kDa Aequorea victoria green fluorescent protein and the amino terminus of the 25-kDa PVX coat protein, assembled into virions and moved both locally and systemically. The PVX.GFP-CP virions were over twice the diameter of wild-type PVX virions. Assembly of PVX.GFP-CP virions required the presence of free coat protein subunits in addition to the fusion protein subunits. PVX.GFP-CP virions accumulated as paracrystalline arrays in infected cells similar to those seen in cells infected with wild-type PVX The formation of virions carrying large superficial fusions illustrates a novel approach for production of high levels of foreign proteins in plants. Aggregates of PVX.GFP-CP particles were fluorescent, emitting green light when excited with ultraviolet light and could be imaged using confocal laser scanning microscopy. The detection of virus particles in infected tissue demonstrates the potential of fusions between the green fluorescent protein and virus coat protein for the non-invasive study of virus multiplication and spread.

Amino Acid Sequence↗
PubMed1996

Minocycline induced autoimmune hepatitis and systemic lupus erythematosus-like syndrome.

Monocycline is the most widely prescribed systemic antibiotic for acne largely because it needs to be given only once or twice a day and seems not to induce resistance. Up to April 1994 11 cases of minocycline induced systemic lupus erythematosus and 16 cases of hepatitis had been reported to the Committee on Safety of Medicines. An analysis of these cases together with seven other cases shows the severity of some of these reactions. Two patients died while taking the drug for acne and a further patient needed a liver transplant. Acne itself can induce arthritis and is often seen in association with autoimmine liver disease, but the clinical and biochemical resolution seen after withdrawal of the drug, despite deterioration of the acne, suggests a drug reaction. In five cases re-exposure led to recurrence. Because reactions may be severe early recognition is important to aid recovery and also to avoid invasive investigations and treatments such as corticosteroids and immunosuppresants. Safer alternatives should be considered for treating acne.

Acne Vulgaris↗
PubMed1996

Infinitesimal risk as public health crisis: news media coverage of a doctor-patient HIV contact tracing investigation.

Among the most prominent health or medical stories covered in 1994 by the Australian news media was that concerning an HIV positive hospital obstetrician and the attempt by the New South Wales Health Department to trace and test 149 women on whom he had operated. All press and television coverage of the issue was reviewed. The surface news narrative of the search for missing, "innocent" mothers potentially infected with a deadly and infectious illness is shown to serve as a "hard news" pretext enabling a wider major discourse to operate about a health system accused as being captive to gay and civil libertarian politics, allowing "guilty" doctors at high risk of HIV to endanger "innocent" patients. Expert consensus held that the women were at "infinitesimal risk" of acquiring HIV. However, media accounts of the investigation all but belied this, illustrating that the news media's framing of risk has more to do with its reproduction of moral outrage components than with "scientific" notions of calculable risk.

Attitude to Health↗
PubMed1996

Semantic memory following pediatric head injury: relationship to age, severity of injury, and MRI.

The effects of closed head injury (CHI) severity (mild vs. severe) and age at injury were analyzed in a longitudinal study (3. 12 months postinjury) of semantic memory which used magnetic resonance imaging (MRI) to characterize focal brain lesions. Semantic memory was evaluated by word and category fluency, semantic verification, semantic clustering in word list recall, and vocabulary. Episodic memory was assessed by word list recall. Comparison of normal control (n = 104) data with the patients' data (n = 77) at 3 months postinjury disclosed semantic and episodic memory deficits in the severe CHI patients. Analysis of the longitudinal data revealed significant effects of age at injury for all of the semantic memory measures. The effects of injury severity were confined to the latency of verifying correct statements. Volume of left frontal and extrafrontal lesions was predictive of performance on several semantic memory measures, but less robust for right hemisphere lesions.

Adolescent↗