PubMed Health⌕ Search

Biomedical subjects

A Leyland

Publications and source records attributed to A Leyland.

At least 19 recordsLinked to original sources
PubMed2005

Electromyography as a measure of peak and cumulative workload in intermediate care and its relationship to musculoskeletal injury: an exploratory ergonomic study.

Injury rates in Intermediate Care (IC) facilities are high and the factors related to these injuries are unclear. The objectives of this exploratory sub-study, which is part of a large multi-faceted study in 8 IC facilities are to: (1) evaluate EMG measured over a full-shift in the back and shoulders of 32 care aides (CAs) as an indicator of peak and cumulative workload (n = 4 x 8 facilities); investigate the relationship between EMG measures and injury indicators; and explore the relationship between EMG measures and other workload measurements. Lumbar EMG was converted to predicted cumulative spinal compression and ranged in CAs from 11.7 to 22.8 MNs with a mean of 16.4 MNs. Average compression was significantly different during different periods of the day (p < 0.001) with highest compression during pre-breakfast when CAs assist most with activities of daily living. Significant differences were found in average compression between low and high injury facilities for 3 of 5 periods of the day (p < 0.010). Peak compressions exceeding 3400 N occurred for very little of the workday (e.g. 11.25s during the 75 min period pre-breakfast). Peak neck/shoulder muscle activity is low (99% APDF ranged from 8.33% to 28% MVC). Peak and cumulative spinal compression were significantly correlated with lost-time and musculoskeletal injury rates as well as with total tasks observed in the CAs (p < 0.01). Perceived exertion was only correlated with peak compressions (p < 0.01). Facilities with low injury rates provided significantly more CAs (p < 0.01) to meet resident needs, and subsequently CAs performed fewer tasks, resulting in less peak and cumulative spinal loading over the day.

Back↗
PubMed2001

Effects of solution pH and electrical parameters on hydroxyapatite coatings deposited by a plasma-assisted electrophoresis technique.

Hydroxyapatite (HA) coatings can be deposited using a hybrid process of plasma electrolysis and electrophoresis, called plasma-assisted electrophoretic deposition (PEPD). HA aqueous suspensions with various pH values were prepared using a modified ultrasonic cleaning bath as an agitator/stirrer. Both DC and unbalanced AC power supplies were used to bias the titanium alloy substrate materials employed in this work. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to observe and analyze coating morphology and microstructure. It was shown that the morphology and composition of the calcium phosphate coatings were significantly influenced by solution pH values; the level of "pure" HA in the coatings' composition corresponded to both solution pH and the type of power supply employed. Loss of hydroxyl radials (i.e., dehydroxylation), which degrades the performance of the hydroxyapatite coating in terms of long-term chemical and mechanical stability, can be virtually eliminated by a combination of high pH and unbalanced AC plasma power. In addition, the underlying TiO2 coatings used to support the HA layer (preproduced by plasma electrolysis process) have a nanoscaled (10-20 nm) polycrystalline structure. TEM studies also revealed a dense, continuous amorphous titania layer (10 nm in thickness) at the interface between the Ti alloy substrate and the TiO2 layer, which may play a role in improving the corrosion resistance of the substrate. Such a nanophase TiO2 layer (if used as a coating alone) may also provide a further improvement in osteoinductive properties, compared to a conventional TiO2 coating on the Ti alloy substrate.

Alloys↗
PubMed2001

Pragmatic randomised controlled trial to evaluate guidelines for the management of infertility across the primary care-secondary care interface.

OBJECTIVE: To investigate the effect of clinical guidelines on the management of infertility across the primary care-secondary care interface. DESIGN: Cluster randomised controlled trial. SETTING: General practices and NHS hospitals accepting referrals for infertility in the Greater Glasgow Health Board area. PARTICIPANTS: All 221 general practices in Glasgow; 214 completed the trial. INTERVENTION: General practices in the intervention arm received clinical guidelines developed locally. Control practices received them one year later. Dissemination of the guidelines included educational meetings. MAIN OUTCOME MEASURES: The time from presentation to referral, investigations completed in general practice, the number and content of visits as a hospital outpatient, the time to reach a management plan, and costs for referrals from the two groups. RESULTS: Data on 689 referrals were collected. No significant difference was found in referral rates for infertility. Fewer than 1% of couples were referred inappropriately early. Referrals from intervention practices were significantly more likely to have all relevant investigations carried out (odds ratio 1.32, 95% confidence interval 1.00 to 1.75, P=0.025). 70% of measurements of serum progesterone concentrations during the midluteal phase and 34% of semen analyses were repeated at least once in hospital, despite having been recorded as normal when checked in general practice. No difference was found in the proportion of referrals in which a management plan was reached within one year or in the mean duration between first appointment and date of management plan. NHS costs were not significantly affected. CONCLUSIONS: Dissemination of infertility guidelines by commonly used methods results in a modest increase in referrals having recommended investigations completed in general practice, but there are no detectable differences in outcome for patients or reduction in costs. Clinicians in secondary care tended to fail to respond to changes in referral practice by doctors. Guidelines that aim to improve the referral process need to be disseminated and implemented so as to lead to changes in both primary care and secondary care.

Cost-Benefit Analysis↗
PubMed1996

Multilevel models: applications to health data.

This paper presents an introductory account of multilevel models, highlighting the potential benefits that may be gained by the use of these methods. It draws on recent applications in health services research that have appeared in the literature. Methodological advances in these statistical techniques have taken place in the field of education, where empirical studies have mainly been concerned with comparing pupil achievement across different schools by exploring the relationship between individual and institutional factors. Although recent widespread availability of suitable software packages has enabled other disciplines to adopt these methods, to date they have received little attention in the health services research literature (the investigation of effects of geographical areas on health being a possible exception) despite their obvious application in many areas of current interest. Key areas that could benefit greatly from these techniques include the exploration of variations in clinical practice, comparisons of institutional performance and resource allocation.

Health Behavior↗
PubMed1993

Estimating the population prevalence of injection drug use and infection with human immunodeficiency virus among injection drug users in Glasgow, Scotland.

Although data on the prevalence of injection drug use are an essential prerequisite for estimating the number of individuals infected with the human immunodeficiency virus (HIV), there have been few attempts to utilize statistical methods of population estimation based on multiple data sources. Data on 3,670 cases (2,866 individuals) were obtained from the HIV test register, drug treatment agencies, police records, and needle and syringe exchanges in Glasgow, Scotland, in 1990. Log-linear analysis was used to model the number of individuals in each of the sources. The model incorporating dependency among the three health care agencies (HIV test, drug treatment, and needle exchange) and independence of the police sample fitted the data well, with a residual chi 2 value of 2.9 (6 df). The expected value of the missing cell corresponding to absence from all four samples was 5,628, yielding an overall estimate of 8,494 injectors (95% confidence interval (CI) 7,491-9,721), for a prevalence rate of 1.35% for people aged 15-55 years in Glasgow during 1990. The high ratio of known to unknown injectors (1:2) resulted from the extensive coverage of known injectors and the relatively high level of overlap between the combined health care agency sample and the police sample. While further analysis demonstrated that the probability of appearing in the four samples varied by age and sex, heterogeneity in the population did not affect the choice of model or substantially alter the estimates for the total number of unknown injectors. A concurrent study of a community-wide sample of 503 injectors resulted in an HIV prevalence rate of 1.1% (95% CI 0.4-2.5%). The results of these studies were combined to produce a further estimate of 93 HIV-infected current injectors in Glasgow (95% CI 33-214).

Adolescent↗
PubMed1993

Biomechanical comparison of carpet-stretching devices.

Peak impact forces, measured from seven male carpetlayers using a knee-kicker over 39 trials were 2933 N (SD 397), taking 9.5 ms (SD +/- 1.1) to reach peak. The knee-kicking cycle involved high knee decelerations of 880 m.s-2 (SD +/- 271). Angles at peak force for the knee (63 degrees SD +/- 10 degrees) and hip (80 degrees SD +/- 35 degrees) showed considerable variation between individuals. Kneeling forces on the non-kicking leg during the kick cycle were 894 N: comparative forces were 368 N and 476 N measured during use of the power stretcher and crab re-stretcher, respectively. Under dynamic conditions the effective mechanical advantage of the knee-kicker was less than 1.0. In comparison, the mechanical advantage of the power stretcher was approximately 14 times greater over the stretch action. When tested with a crab re-stretcher, the breaking strength of the smooth-edge to which the carpet attaches averaged 2384 N (SD +/- 245). Design guidelines for an improved carpet stretching device are provided.

Biomechanical Phenomena↗
PubMed1993

Patterns of neuropsychological function in a low-birthweight population.

An investigative analysis was carried out of the neuromotor and cognitive findings in a population-based study of low-birthweight infants (< 1750g) at 4 1/2 years of age to try to improve the understanding of the neuropathological basis of their deficits. Cluster analysis identified groups of children whose performance in the cognitive subscales of the British Ability Scales followed similar patterns, and also differentiated between children in neuromotor competence. Cluster membership correlated highly with language attainment, ability to copy shapes, behaviour as reported by parents and parents' and examiners' perception of attention span. Children in poorer-performing clusters were more likely to be born to mothers who had had a previous perinatal death, and were also more likely to have experienced septicaemia during the neonatal period. These findings are discussed in the light of evidence from the neuropathological and physiological literature.

Analysis of Variance↗
PubMed1992

Female streetworking prostitution and HIV infection in Glasgow.

OBJECTIVES: To identify the extent of HIV infection and injecting drug use among female streetworking prostitutes in Glasgow; to estimate the size of the female streetworking prostitute population in the city; and to estimate the number of HIV positive women working as prostitutes on the streets in Glasgow. DESIGN: Observation and interviewing of female prostitutes over seven months in red light district; analysis of saliva samples for presence of antibodies to HIV; capture-recapture approach to estimating the size of the female streetworking prostitute population. SETTING: Glasgow. SUBJECTS: 206 female streetworking prostitutes. MAIN OUTCOME MEASURES: Number of women with antibodies to HIV, self reported use of injecting drugs, history of contact with 206 women. RESULTS: Saliva samples were requested from 197 women; 159 (81%) provided samples. Four (2.5%, 95% confidence interval 0.7%-6.3%) of the samples were positive for HIV, all of which had been provided by women who injected drugs. Of the 206 streetworking women contacted 147 (71%) were injecting drug users. About 1150 women are estimated to work on the streets in Glasgow over a 12 month period. CONCLUSIONS: HIV is not as widespread among female prostitutes as many reports in the tabloid press suggest. A greater proportion of female streetworking prostitutes in Glasgow are injecting drugs than has been reported for other British cities.

Female↗
PubMed1991

Estimating hidden populations: a new method of calculating the prevalence of drug-injecting and non-injecting female street prostitution.

This paper outlines a new method we have developed for estimating the prevalence of streetworking prostitution and the proportions of female street-working prostitutes who are injecting drug users. This method is based on the capture/recapture approach and involves distinguishing new fieldwork contacts from repeat field work contacts. The size of the overall population can be modelled from records of the increasing ratio of repeat to new fieldwork contacts. The method may have a relevance beyond a concern with prostitution and drug injecting, and may be of value in estimating other hidden populations.

Female↗
PubMed1990

Injecting drug use and female street-working prostitution in Glasgow.

There are considerable difficulties associated with calculating the prevalence of covert, illegal and stigmatized activities. This paper outlines new methods we have developed for calculating the prevalence of both drug-injecting street prostitution and non-injecting street prostitution in Glasgow. Our data indicate that Glasgow has a much higher level of injecting drug use than has been reported among prostitutes in other British cities.

Female↗