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Biomedical subjects

P Coleman

Publications and source records attributed to P Coleman.

At least 37 records · Page 2Linked to original sources
PubMed2001

Is the quantum dot at large bias a weak-coupling problem?

We examine the two-lead Kondo model for a dc-biased quantum dot in the Coulomb blockade regime. From perturbative calculations of the magnetic susceptibility, we show that the problem retains its strong-coupling nature, even at bias voltages larger than the equilibrium Kondo temperature. We give a speculative discussion of the nature of the renormalization group flows and the strong-coupling state that emerges at large voltage bias.

Journal Article↗
PubMed2001

SMART: The microstent's ability to limit restenosis trial.

In this randomized, prospective, multicenter trial (n = 661) of patients with de novo or restenotic coronary lesions, 330 patients received the MicroStent(R) II (MSII), and 331 received the Palmaz-Schatz (PS) stent. The short-term procedural success rates were 94.4% and 95.7%, respectively (P = 0.47). The 30-day cumulative incidence of major adverse events [death, myocardial infarction, CVA, target lesion revascularization (TLR)] was 6.4% for the MSII and 4.5% for the PS stent (P = 0.31). The in-stent binary restenosis rate at 6 months was 25.2% for the MSII and 22.1% for the PS stent (P = 0.636). Using Kaplan-Meier estimates, the incidence of clinically driven TLR was 8.9% for the MSII and 9.2% for the PS stent at 180 days; at 270 days, it was 12.8% and 12.1%, respectively (P = 0.83). MSII and the PS stents were comparable with respect to short-term procedural success, complications, and late clinical and angiographic restenosis.

Aged↗
PubMed2001

Use and expenditure on complementary medicine in England: a population based survey.

OBJECTIVES: Many claims are made that complementary medicine use is a substantial and growing part of health-care behaviour. Estimates of practitioner visits in the USA and Australia indicate high levels of use and expenditure. No reliable population-based estimates of practitioner use are available for the UK. METHODS: In 1998, a previously piloted postal questionnaire was sent to a geographically stratified, random sample of 5010 adults in England. The questionnaire focuses on practitioner contacts, but also asked about the purchase of over-the-counter remedies. Additional information was requested on socio-demographic characteristics, perceived health, and recent NHS resource use. Information on use included reason for encounter, expenditure, insurance, and location of visit. MAIN OUTCOMES MEASURES: Population estimates (by age group and sex) of lifetime use and use in the past 12 months for acupuncture, chiropractic, homoeopathy, hypnotherapy, medical herbalism, osteopathy. Estimates for two additional therapies (reflexology and aromatherapy), and homoeopathic or herbal remedies purchased over-the-counter. Estimates of annual out-of-pocket expenditure on practitioner visits in 1998. RESULTS: A crude response rate of 60% was achieved (adjusted response rate 59%). Responders were older and more likely to be female than non-responders. Usable responses (n = 2669) were weighted using the age/sex profile of the sample frame. From these adjusted data we estimate that 10.6% (95% CI 9.4 to 11.7) of the adult population of England had visited at least one therapist providing any one of the six more established therapies in the past 12 months (13.6% for use of any of the eight named therapies, 95% CI 12.3 to 14.9). If all eight therapies, and self-care using remedies purchased over the counter are included, the estimated proportion rises to 28.3% (95% CI 26.6 to 30.0) for use in the past 12 months, and 46.6% (95% CI 44.6 to 48.5) for lifetime use. All types of use declined in older age groups, and were more commonly reported by women than men (P < 0.01 for all comparisons). An estimated 22 million visits were made to practitioners of one of the six established therapies in 1998. The NHS provided an estimated 10% of these contacts. The majority of non-NHS visits were financed through direct out-of-pocket expenditure. Annual out-of-pocket expenditure on any of the six more established therapies was estimated at pound 450 million (95% CI 357 to 543). CONCLUSION: This survey has demonstrated substantial use of practitioner-provided complementary therapies in England in 1998. The findings suggest that CAM is making a measurable contribution to first-contact primary care. However, we have shown that 90% of this provision is purchased privately. Further research into the cost-effectiveness of different CAM therapies for particular patient groups is now urgently needed to facilitate equal and appropriate access via the NHS.

Adult↗
PubMed2001

Will alternative immediate care services reduce demands for non-urgent treatment at accident and emergency?

OBJECTIVES: To estimate the potential of general practice, minor injury units, walk in centres and NHS Direct to reduce non-urgent demands on accident and emergency (A&E) departments taking into account the patient's reasons for attending A&E. METHODS: A questionnaire survey and notes review of 267 adults presenting to the A&E department of a large teaching hospital in Sheffield, England, triaged to the two lowest priority treatment streams, was conducted over seven weeks. Using defined criteria, patients were classified by the suitability of the presenting health problem to be managed by alternative immediate care services or only by A&E, and also by the likelihood, in similar circumstances, of patients presenting to other services given their reasons for seeking A&E care. RESULTS: Full data were obtained for 96% of participants (255 of 267). Using objective criteria, it is estimated that 55% (95% CI 50%, 62%) of the health problems presented by a non-urgent population attending A&E are suitable for treatment in either general practice, or a minor injury unit, or a walk in centre or by self care after advice from NHS Direct. However, in almost one quarter (24%) of low priority patients who self referred, A&E was not the first contact with the health services for the presenting health problem. The reason for attending A&E cited most frequently by the patients was a belief that radiography was necessary. The reason given least often was seeking advice from a nurse practitioner. Taking into account the objective suitability of the health problem to be treated elsewhere, and the reasons for attending A&E given by the patients, it is estimated that, with similar health problems, as few as 7% (95% CI 3%, 10%) of the non-urgent A&E population may be expected to present to providers other than A&E in the future. CONCLUSIONS: The increasing availability of alternative services offering first contact care for non-urgent health problems, is likely to have little impact on the demand for A&E services.

Adult↗
PubMed2001

Influence of evidence-based guidance on health policy and clinical practice in England.

OBJECTIVES: To examine the influence of evidence-based guidance on health care decisions, a study of the use of seven different sources and types of evidence-based guidance was carried out in senior health professionals in England with responsibilities either for directing and purchasing health care based in the health authorities, or providing clinical care to patients in trust hospitals or in primary care. DESIGN: Postal survey. SETTING: Three health settings: 46 health authorities, 162 acute and/or community trust hospitals, and 96 primary care groups in England. SAMPLE: 566 subjects (46 directors of public health, 49 directors of purchasing, 375 clinical directors/consultants in hospitals, and 96 lead general practitioners). MAIN OUTCOME MEASURES: Knowledge of selected evidence-based guidance, previous use ever, beliefs in quality, usefulness, and perceived influence on practice. RESULTS: A usable response rate of 73% (407/560) was achieved; 82% (334/407) of respondents had consulted at least one source of evidence-based guidance ever in the past. Professionals in the health authorities were much more likely to be aware of the evidence-based guidance and had consulted more sources (mean number of different guidelines consulted 4.3) than either the hospital consultants (mean 1.9) or GPs in primary care (mean 1.8). There was little variation in the belief that the evidence-based guidance was of "good quality", but respondents from the health authorities (87%) were significantly more likely than either hospital consultants (52%) or GPs (57%) to perceive that any of the specified evidence-based guidance had influenced a change of practice. Across all settings, the least used route to accessing evidence-based guidance was the Internet. For several sources an effect was observed between use ever, the health region where the health professional worked, and the region where the guidance was produced or published. This was evident for some national sources as well as in those initiatives produced locally with predominantly local distribution networks. CONCLUSIONS: The evidence-based guidance specified was significantly more likely to be seen to have contributed to the decisions of public health specialists and commissioners than those of consultants in hospitals or of GPs in a primary care setting. Appropriate information support and dissemination systems that increase awareness, access, and use of evidence-based guidance at the clinical interface should be developed.

Attitude of Health Personnel↗
PubMed2000

Onset of antiferromagnetism in heavy-fermion metals

There are two main theoretical descriptions of antiferromagnets. The first arises from atomic physics, which predicts that atoms with unpaired electrons develop magnetic moments. In a solid, the coupling between moments on nearby ions then yields antiferromagnetic order at low temperatures. The second description, based on the physics of electron fluids or 'Fermi liquids' states that Coulomb interactions can drive the fluid to adopt a more stable configuration by developing a spin density wave. It is at present unknown which view is appropriate at a 'quantum critical point' where the antiferromagnetic transition temperature vanishes. Here we report neutron scattering and bulk magnetometry measurements of the metal CeCu(6-x)Au(x), which allow us to discriminate between the two models. We find evidence for an atomically local contribution to the magnetic correlations which develops at the critical gold concentration (x(c) = 0.1), corresponding to a magnetic ordering temperature of zero. This contribution implies that a Fermi-liquid-destroying spin-localizing transition, unanticipated from the spin density wave description, coincides with the antiferromagnetic quantum critical point.

Journal Article↗
PubMed2000

Gap-anisotropic model for the narrow-Gap kondo insulators

A theory is presented which accounts for the dynamical generation of a hybridization gap with nodes in the Kondo insulating materials CeNiSn and CeRhSb. We show that Hund's interactions acting on virtual 4f(2) configurations of the cerium ion can act to dynamically select the shape of the cerium ion by generating a Weiss field which couples to the shape of the ion. In low symmetry crystals where the external crystal fields are negligible, this process selects a nodal Kondo semimetal state as the lowest energy configuration.

Journal Article↗
PubMed2000

'Scraps': hidden nursing information and its influence on the delivery of care.

What nurses commonly describe as 'scraps' are defined as the personalized recordings of information that is routinely made on any available piece of paper (hence scraps) or in small notebooks. The use of scraps is common in practice and has been noted in research from across the globe. Drawing on an empirical study it is argued that scraps are a unique combination of personal and professional knowledge that informs the delivery of care. The overall aim of the study was to discover how nurses define and communicate information about patients and the delivery of care to each other on an elderly care unit. The processes by which information was constructed and the organizational structure and interactions that influenced this were also identified. The research design was an ethnographic one that involved: observations of formal nursing end of shift reports (23 handovers) and informal interactions between nurses (146 hours); interviews (n + 34) with registered nurses, student nurses and nursing auxiliaries; and analysis of written records. Data were collected from five acute elderly care wards at a district general hospital in the south of England. A grounded theory analysis was undertaken which revealed that scraps may have a significant role in the communication of information and the delivery of care. Therefore a categorization of scraps within three main themes was undertaken. First, the analysis revealed the processes involved in the construction of scraps. Second, the content and role of scraps in influencing the delivery of care was exposed. Finally, the potentially confidential nature of scraps and consequent problems of storage and disposal was recognized. The findings are discussed in relation to a suggested model of the interrelationship between paperwork, scraps, handovers and the delivery of nursing care. It is concluded that scraps are significant in facilitating nursing care and that this should be recognized in research, education and practice.

Aged↗
PubMed2000

Interactions between nurses during handovers in elderly care.

This paper explores the role of nursing interaction within the context of handovers and seeks to identify the clinical discourses used by registered nurses, student nurses and care assistants in acute elderly care wards, to determine their influence on the delivery of patient care. The study design involved an ethnographic approach to data collection which involved: observations of formal nursing end of shift reports (23 handovers) and informal interactions between nurses (146 hours); interviews (n = 34) with registered nurses, student nurses and care assistants; and analysis of written nursing records. A grounded theory analysis was undertaken. Data were collected from five acute elderly care wards at a district general hospital in the south of England. Results from this empirical study indicate that handovers were formulaic, partial, cryptic, given at high speed, used abbreviations and jargon, required socialized knowledge to interpret, prioritized biomedical accounts and emphasized physical aspects of care. Patients' resuscitation status was highly salient to all grades of nurse. Doing 'paperwork' was accorded less status and priority than patient care, and was regarded as excessively time consuming. Despite this, there was evidence of repetition in nursing documents. Moreover, the delivery of clinical nursing appeared to be guided by personal records rather than formal records.

Adult↗
PubMed1999

Serum from hemodialysis patients inhibits basal and cytokine-stimulated tissue factor expression in vitro.

Hemorrhagic complications are common among hemodialysis (HD) patients. The mechanisms by which HD perturbs the coagulation cascade are still being defined. This study evaluated the influence of HD serum on cellular expression of tissue factor (TF), a procoagulant membrane-associated protein that is a pivotal regulator of blood coagulation. Serum was collected immediately before dialysis and 15, 30, and 180 min into HD using polysulfone membranes. Serum was then assessed for its ability to influence basal and cytokine-stimulated TF activity in human umbilical vein endothelial cells and ECV304 cells. Predialysis serum did not influence basal levels of TF activity. HD was associated with the appearance of a serum factor that suppressed basal TF activity (TF units/microg protein: predialysis serum 8.2 +/- 0.9; 180-min dialysis serum 4.9 +/- 0.6; P < 0.05) and TF activity induced by the cytokine tumor necrosis factor-alpha (TNFalpha) (TF units/microg protein: TNFalpha alone 15.9 +/- 0.7; TNFalpha + 180-min dialysis serum 5.9 +/- 0.9; P < 0.01). This response was not mimicked by heparin, suggesting production of an endogenous inhibitor of TF activity during HD. Dialysis was associated with a striking increase in circulating levels of tissue factor pathway inhibitor (TFPI), a physiologic inhibitor of the TF/VIIa complex. The lack of temporal correlation between TFPI levels and suppression of TF activity, however, suggested the presence of additional TFPI independent pathway(s) for modulation of TF activity. Dialysis-related suppression of TF expression may contribute to hemorrhagic complications in HD patients.

Adult↗