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Biomedical subjects

S Grieve

Publications and source records attributed to S Grieve.

9 recordsLinked to original sources
PubMed2006

Orientational order of Australian spider silks as determined by solid-state NMR.

A simple solid-state NMR method was used to study the structure of (13)C- and (15)N-enriched silk from two Australian orb-web spider species, Nephila edulis and Argiope keyserlingi. Carbon-13 and (15)N spectra from alanine- or glycine-labeled oriented dragline silks were acquired with the fiber axis aligned parallel or perpendicular to the magnetic field. The fraction of oriented component was determined from each amino acid, alanine and glycine, using each nucleus independently, and attributed to the ordered crystalline domains in the silk. The relative fraction of ordered alanine was found to be higher than the fraction of ordered glycine, akin to the observation of alanine-rich domains in silk-worm (Bombyx mori) silk. A higher degree of crystallinity was observed in the dragline silk of N. edulis compared with A. keyserlingi, which correlates with the superior mechanical properties of the former.

Animals↗
PubMed2002

Electromagnetic characterisation of MR RF coils using the transmission-line modelling method.

The Transmission-Line Modelling (TLM) method is applied to the electromagnetic characterisation of RF coils and samples for magnetic resonance imaging MRI. Theoretical verification was performed using a simple surface coil. Experimental verification was performed using Alderman-Grant and birdcage coils constructed for use on a 7 T micro-imaging system. The modelling method enabled electromagnetic characteristics of frequency response, electromagnetic field generation, energy stored and power loss to be determined. From these parameters, coil resonant modes, B1 field profiles, voltages, currents, quality factor (Q), pi/2 pulse length, and the equivalent lumped-element circuit components of resistance, inductance and capacitance were calculated. Equations are presented that enable a comprehensive electromagnetic characterisation of the RF coil and sample to be achieved based on the results of the TLM simulations. The use of the TLM method is extended to include the design of safe arbitrary multi-nuclear pulse sequences such that the specific absorption rate (SAR) of tissue, and RF coil component safety limits are not exceeded.

Algorithms↗
PubMed2000

Local and systemic effects of intra-arterial desmopressin in healthy volunteers and patients with type 3 von Willebrand disease. Role of interleukin-6.

Intra-arterial desmopressin caused dose and time dependent increases (p <0.001 for all) in forearm blood flow (all doses) and plasma tissue plasminogen activator (t-PA) concentrations (desmopressin > or = 70 ng/min). Although plasma t-PA concentrations rose in both forearms, there was a modest local release of t-PA in the infused forearm (14 ng/100 mL of tissue/min, p <0.05). At desmopressin doses > or = 300 ng/min, plasma von Willebrand factor (vWf) and Factor VIII:C concentrations rose in both forearms (p <0.001) and correlated with the rise in interleukin-6 concentrations (r = 0.92, p <0.001: r = 0.85, p = 0.002 respectively). Neither desmopressin nor substance P caused t-PA, vWf or Factor VIII:C release in the patients, although desmopressin increased plasma interleukin-6 concentrations as in healthy volunteers. We conclude that desmopressin releases t-PA, vWf and Factor VIII:C predominantly via systemic mechanisms, possibly mediated by cytokine release. Patients with type 3 vWD appear to have a generalised failure to release t-PA acutely despite a normal interleukin-6 response to desmopressin infusion.

Adult↗
PubMed2000

Prenatal education for mothers with disabilities.

Prenatal nurse educators are well prepared to meet the learning needs of many expectant mothers. But how prepared are they to meet the learning needs of mothers with disabilities? To answer this question, eight mothers with various chronic illnesses located in north-eastern Ontario, Canada were asked to describe their maternity experiences. Given the small convenience sample and exploratory nature of the study, a qualitative content analysis was done. The mothers' reports described interaction with a variety of health professionals. This analysis focuses on findings specific to nurses who provide prenatal education. In general, mothers reported they had received insufficient, inappropriate information, especially about their pregnancy and chronic illnesses. The mothers thought that nurses doubted the ability of women with disabilities to be decision-makers or responsible and 'proper' mothers. Suggestions by disabled mothers for quality care in prenatal education are described. A more emancipatory approach to preparing nurses for practice as prenatal educators is recommended. Such an approach can reduce the barriers associated with power differences between women with disabilities as 'learners' and their nurse 'teachers'.

Adult↗
PubMed1997

Measuring morale--does practice area deprivation affect doctors' well-being?

BACKGROUND: Morale is a perennial concern in general practice and, over the years, a variety of tools have been used to examine doctors' mental well-being in a range of psychological and sociological studies. Despite perceived associations between low morale and practice area deprivation, this has not been investigated previously. AIM: To devise and apply a measure of mental well-being in general practitioners, and to use this to investigate the effect of practice area deprivation. METHOD: A questionnaire was devised and piloted, then used in an anonymous postal survey of a random sample of 500 London general practitioners, with questions on demography, workload, practice characteristics, patient centredness, and practice area deprivation. RESULTS: A total of 334 (68%) doctors replied to the questionnaire. Of these, 45% often feel exhausted, 46% are often frustrated by trivial consultations, and a third are seriously disenchanted with work. The resulting well-being score had a normal distribution, was reproducible (test-retest reliability = 0.91), and was internally consistent (Cronbach's alpha = 0.76). Comments from respondents suggested good face validity. Low well-being was not associated with practice area deprivation, but was associated with time stress, small practices and primary care teams, and lack of patient centredness. CONCLUSION: The instrument provided a useful tool for examining doctors' well-being and the associations thereof. Well-being was not associated with practice area deprivation. Help for small primary care teams and measures to reduce time stress should help to improve morale.

Catchment Area, Health↗
PubMed1975

Alpha-chain disease in a non-Mediterranean climate. A case report.

The clinical, biochemical, immunological and histopathological features in a patient with alpha-chain disease are described. The patient, a 20-year-old Coloured man, presented with severe steatorrhoea, malabsorption, abdominal pain and progressive general deterioration. An heterogeneous abnormal band with IgA immunochemical specificity was detected on electrophoresis of the patient's serum and urine. This protein was identified as free alpha-chain and was present in serum, urine, saliva and jejunal juice. A jejunal mucosal biopsy specimen showed distinctive appearances associated with alpha-chain disease. Bone marrow involvement was found and abnormal lymphoid cells were seen in the circulation together with an increased B lymphocyte population derived from bone marrow. This is the third South African patient with alpha-chain disease to be diagnosed. The patient has shown a partial remission after 12 months' chemotherapy. There was rapid symptomatic response and normalisation of protein parameters which were not paralleled by an objectively discernible response as assessed by haematological examination, intestinal absorption studies and histology of the jejunal mucosa.

Adult↗