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Biomedical subjects

R Brooks

Publications and source records attributed to R Brooks.

At least 19 recordsLinked to original sources
PubMed2006

Ultrasonic treatment to improve anaerobic digestibility of dairy waste streams.

The dairy-processing industry generates various types of organic wastes, which are utilised as stock feed, for anaerobic digestion, spread on land or alternatively land-filled at high costs. Owing to the generation of renewable energy, anaerobic digestion is an attractive option for many factories. To enhance the biological degradation process, a mechanical disintegration of various waste dairy streams was undertaken. While the successful application of ultrasonic treatment has been reported for various municipal waste streams, limited information was available for dairy industry applications. The results of this study showed that ultrasonic treatment can improve the digestibility of the more problematic dairy waste streams, such as sludges, by breaking down micro-organisms' cell walls and releasing soluble cell compounds. For more soluble streams, such as dairy factory effluent, an increased gas production was observed and attributed to the reduced particle size of the fat globules.

Anaerobiosis↗
PubMed2005

Effect of carbonate substitution on the ultrastructural characteristics of hydroxyapatite implants.

Carbonate ion substitution has been shown to be beneficial for increasing the amount of in vivo osseointegration to hydroxyapatite (HA). Nevertheless, mechanisms by which carbonate ions increase in vivo bioactivity are not fully understood. Sintered granules of HA and carbonate-substituted hydroxyapatite (CHA) were implanted for 6 and 12 weeks in an ovine model. Samples containing the bone-implant interface were prepared for transmission electron microscopy (TEM) and TEM was used to compare the in vivo reactivity of sintered granules of HA and CHA. The current findings demonstrated that CHA (1.2 and 2.05 wt.%) is more soluble than pure HA in vivo. More dissolution was observed from the CHA, at the bone-implant interface and within the implant, when compared to pure HA. A less crystalline phase was formed between the 2.05 wt.% CHA and bone at 12 weeks in vivo. Bone surrounding both the pure HA and 1.2 wt.% CHA was relatively disorganised at 12 weeks. In comparison, bone surrounding the 2.05 wt.% CHA was considerably more organised and in many regions collagen fibrils were present. Despite increased quality of bone surrounding 2.05 wt.% CHA, compared to 1.2 wt.% CHA, the amount of dissolution from both materials was similar.

Animals↗
PubMed2005

Benefits of interprofessional learning: an interprofessional MSc in child health.

This article addresses interprofessional education (IPE) using a case study evaluating a multidisciplinary MSc course in child health. The participants felt that the nature of the course increased their interprofessional working skills and professional confidence. They described benefits, including new insights, a balanced variety of views, development of respect and equality between professionals, improved communication and a holistic approach to child health.

Child↗
PubMed2004

Mechanical properties of glass-ceramic A-W-polyethylene composites: effect of filler content and particle size.

Composites which comprise a bioactive filler and ductile polymer matrix are desirable as implant materials since both their biological and mechanical properties can be tailored for a given application. In the present study three-point bending was used to characterise biomedical materials composed of glass-ceramic apatite-wollastonite (A-W) particulate reinforced polyethylene (PE) (denoted as AWPEX). The effects of filler volume fraction, varied from 10 to 50 vol%, and average particle size, 4.4 and 6.7 microm, on the bending strength, yield strength, mode of fracture, Young's modulus and strain to failure were investigated. HAPEX, a commercially used composite of hydroxyapatite and polyethylene, with a 40 vol% filler content, was used for comparison. Increasing the filler content caused an increase in Young's modulus, yield strength and bending strength, and a decreased strain to failure. When filler particle size was increased, the Young's modulus, yield and bending strengths were found to be slightly reduced. A transition in fracture behaviour from ductile to brittle behaviour was observed in samples containing between 30 and 40 vol% filler.

Apatites↗
PubMed2004

Extreme polymorphism in a Y-linked sexually selected trait.

Males of the livebearing fish, Poecilia parae, exhibit one of the most complex polymorphisms known to occur within populations, whereas females are monomorphic. We describe five distinct male colour morphs and an associated size dimorphism, and demonstrate through pedigree analysis that the locus or loci controlling the male colour polymorphism is linked to the Y-chromosome. Field surveys from 1999 to 2002 of nine populations in Guyana and Suriname, South America, indicate that some morphs are consistently abundant and others are rare, implying that the colour polymorphism has important fitness consequences. By rearing offspring of field-inseminated females, we showed that the common morph is also the most successful morph in terms of reproduction. However, dichotomous choice tests show that two rare morphs are preferred by females over the common morph. These results suggest that alternative male mating strategies, sperm competition, overt male-male competition, or other processes are overriding female preferences in these populations. Furthermore, Y-linkage of the colour polymorphism in P. parae supports the hypothesis that heterogametic sex chromosomes harbour sexually antagonistic traits beneficial to the heterogametic sex.

Animals↗
PubMed2004

D-2-hydroxyglutaric aciduria and glutaric aciduria type 1 in siblings: coincidence, or linked disorders?

Glutaric aciduria type 1 (GA1) and D-2-hydroxyglutaric aciduria ( D-2-HGA) are cerebral organic acidurias characterized by the excretion of 3-hydroxyglutaric and D-2-hydroxyglutaric acids, respectively. GA1 is caused by a deficiency of glutaryl-CoA dehydrogenase encoded by the GCDH gene; the biochemical and genetic basis of D-2-HGA is unknown. We diagnosed GA1 in the son of consanguineous Palestinian parents, and D-2-HGA in his sister and brother. All three siblings were neurologically and developmentally normal. A small but abnormal increase in excretion of D-2-hydroxyglutaric acid was also found in the sibling with GA1. These observations suggested a possible pathophysiological link between these two disorders. The sibling with GA1 was homozygous whilst his siblings with D-2-HGA were heterozygous for a 1283 C>T missense mutation (T416I) in exon 11 of the GCDH gene. However, sequence analysis of the GCDH gene in 8 additional unrelated patients with D-2-HGA and 3 with combined D/ L-2-HGA did not reveal any pathogenic mutations. The biochemical and genetic basis of D-2-HGA remains to be determined.

Brain Diseases, Metabolic, Inborn↗
PubMed2004

N-terminal pro-B-type natriuretic peptide: reference plasma levels from birth to adolescence. Elevated levels at birth and in infants and children with heart diseases.

AIM: Determination of plasma levels of N-terminal pro-B-type natriuretic peptide (N-BNP) in infants and children with and without heart diseases. METHODS: Plasma N-BNP was measured in 78 infants and children without heart disease and in 55 infants and children with heart disease causing volume and pressure overload. Heart diseases included chronic dilated cardiomyopathy, acute left ventricular dysfunction, and congenital cardiac anomalies resulting in left and right ventricular volume or pressure overload. The Mann-Whitney rank-sum test and the ANOVA for ranks test were used to compare two or more groups, respectively. RESULTS: N-BNP levels were elevated in the first days of life but were not significantly different in children from 4 mo to 15 y old. The upper limit in children older than 4 mo with no heart disease was 349 pg/ml. In patients with heart disease, N-BNP levels were significantly higher than in control children (p < 0.0001). CONCLUSION: N-BNP levels are elevated in the first days of life and are stable from age 4 mo to adolescence. Elevated N-BNP levels reflect cardiac dysfunction in infants and children.

Adolescent↗
PubMed2003

Buccal cells as a source of DNA for comparative animal genomic analysis.

The source of DNA of adequate quality and quantity is an important consideration in genome analysis. In many animal and livestock species, easy access to DNA will facilitate the rapid and reliable genotyping of a large number of individual individuals. Here, we describe the use, for the first time, of buccal cells from non-human mammalian species as a source of DNA template for PCR and restriction analysis. The buccal cells from the pig, cow and human, were used to amplify PCR fragments that were scanned SNPs and for comparative genome analysis. The work indicates that buccal cells are also adequate sources of DNA for genome analysis of animals that have been identified as priorities in comparative genomics.

Animals↗
PubMed2001

The health of children in refuges for women victims of domestic violence: cross sectional descriptive survey.

OBJECTIVES: To describe the health and developmental status of children living in refugees for women victims of domestic violence and to investigate their access to primary healthcare services. DESIGN: Cross sectional survey. SETTING: Women's refugees in Cardiff. PARTICIPANTS: 148 resident children aged under 16 years and their mothers. MAIN OUTCOME MEASURES: Completeness of records on the child health system (register of all children that includes data on the child's health) for named health visitor, named general practitioner, and immunisation uptake; satisfactory completion of child health surveillance; Denver test results for developmental status; Rutter test scores for behavioural and emotional problems; reports of maternal concerns. RESULTS: 148/257 (58%) children living in refugee between April 1999 and January 2000 were assessed. Child health system data were incorrect (general practitioner and/or address) or unavailable for 85/148 (57%) children. Uptake of all assessments and immunisations was low. 13/68 (19%) children aged <5 years had delayed or questionable development on the Denver test, and 49/101 (49%) children aged 3-15 years had a Rutter score of >10 (indicating probable mental health problems). Concerns were expressed by mothers of 113/148 (76%) children. After leaving the refuge, 22 children were untraceable and 36 returned home to the perpetrator from whom the families had fled. CONCLUSIONS: The children had a high level of need, as well as poor access to services. Time spent in a refuge provides a window of opportunity to review health and developmental status. Specialist health visitors could facilitate and provide support, liaison, and follow up.

Adolescent↗
PubMed2001

Can older males deliver the good genes?

Females of many species choose to mate with old rather than young males, possibly because older males pass superior genes on to their offspring. Recent theoretical and empirical investigations have rejuvenated interest in the evolution of mating preferences based on age, and in the relationship between longevity and fitness. If the cost of signalling is a reduction in future survival and reproduction, mate choice based on age is one possible outcome when males signal their genetic quality. These recent investigations highlight the importance of understanding sexual selection from a life-history perspective.

Journal Article↗
PubMed2001

A sense of history.

Mating preferences for specific traits increase the fertility, fecundity or offspring fitness of choosy individuals. However, current fitness benefits offer an incomplete account of the relative influence of different signals on mate choice. The history of selection on sensory systems in a broader ecological context can provide many missing details. Recent innovative use of neural networks by Phelps and Ryan shows that modelling the chronological order in which past selective forces have acted predicts the actual mating preferences of túngara frogs.

Journal Article↗
PubMed2001

Sheaths for urinary incontinence: a randomized crossover trial.

OBJECTIVE: To evaluate the full range of self-adhesive continence sheaths for men available in the UK and thus provide clinicians and consumers with a basis for product selection. PATIENTS AND METHODS: Fifty-eight volunteers (aged 30-89 years) tested each of six different self-adhesive sheaths available in the UK in September 1998 for 1 week each. Thirty subjects applied the sheaths themselves and 28 subjects relied on a carer to do so. During each week subjects completed a diary recording sheath changes and the result of skin inspection, to note any unscheduled sheath changes (because of sheath detachment) and any skin problems. At the end of each week an 11-item questionnaire was completed using a three-point rating scale ('good', 'acceptable', 'unacceptable') to assess the key aspects of product performance. RESULTS: A significantly higher proportion of subjects scored the 'Aquadry Clear Advantage' sheath as 'good' than four of the other sheaths (P < 0.01) and a significantly higher proportion found the 'Incare' sheath to be 'unacceptable' than all of the other sheaths (P < 0.001) for the 'overall opinion' question. Sheath detachments (sheath falling off or blowing off) for the 'Incare' were significantly more common than for four of the other products (P < 0.01). Sheath detachments for the 'Aquadry Clear Advantage' were significantly less common than for two of the other products (P < 0.01). A significantly higher proportion of subjects found sheaths with an applicator to be 'unacceptable' than sheaths with no applicator (P < 0.001) for the 'ease of putting on' and 'overall opinion' questions (when adjusted for previous product use and person applying the sheath). CONCLUSIONS: There were substantial differences between products in their general performance and ergonomics, and for the frequency of detachment as recorded in the diary. The 'Aquadry Clear Advantage' was particularly successful and the 'Incare' particularly unsuccessful when compared with the other sheaths. Sheaths with no applicators were preferred to those with applicators. Applicators are mainly designed to make sheaths easier to put on, especially for carers, but there was no evidence that carers preferred applicators. This may have implications for manufacturers.

Adult↗
PubMed2001

Coated catheters for intermittent catheterization: smooth or sticky?

OBJECTIVE: To evaluate the current range of hydrophilic-coated catheters for intermittent self-catheterization, focusing on the adherence of the catheter to the urethral mucosa at the end of catheterization. PATIENTS AND METHODS: In a prospective randomized study, 61 community-based men tested each of four different hydrophilic-coated catheters available in the UK at the time. Subjects used each of the four test catheters for 1 week in a random order, and were provided with the number and size of catheter they normally used. To assess the products, the subjects: (i) timed seven catheterizations using a stop-watch to determine the time taken from extracting the catheter from the water-filled package, to removing the catheter from the penis, having emptied the bladder; (ii) recorded the severity of 'sticking' on catheter removal on a three-point scale (not at all, a little, a lot); and (iii) completed a product-performance questionnaire. RESULTS: There were no significant differences in ratings of 'sticking' between the 'Easicath' and 'Lofric' (P > 0.05), but there were significant differences between these two products and the 'Aquacath' and the 'Silky', which were found to 'stick' more (P < 0.001). The 'Silky' was reported to stick significantly more than the 'Aquacath' (P < 0.001). CONCLUSIONS: Adherence to the urethral mucosa on catheter removal was a common problem, occurring with all catheters, but two products were significantly more likely to stick than the other two. The clinical importance of 'sticking' and the long-term implications are currently unknown. The relative 'sticking' of uncoated catheters has also not been established.

Adult↗
PubMed2001

The CPE network: creating an evidence base for continence product selection.

Selecting continence products for an individual patient or hospital contract is often a daunting task. This article describes the evaluation process developed for a program of government-funded multicenter evaluations of continence products established in the United Kingdom to provide an evidence base for product selection. The essential requirements of an evaluation are discussed, together with the methodologic and statistical issues that such evaluations present. The strengths and limitations of multicenter trials are examined and suggestions are made regarding other areas of nursing in which this approach could be usefully adopted.

Catheterization↗
PubMed2001

Female guppies agree to differ: phenotypic and genetic variation in mate-choice behavior and the consequences for sexual selection.

Variation among females in mate choice may influence evolution by sexual selection. The genetic basis of this variation is of interest because the elaboration of mating preferences requires additive genetic variation in these traits. Here we measure the repeatability and heritability of two components of female choosiness (responsiveness and discrimination) and of female preference functions for the multiple ornaments borne by male guppies (Poecilia reticulata). We show that there is significant repeatable variation in both components of choosiness and in some preference functions but not in others. There appear to be several male ornaments that females find uniformly attractive and others for which females differ in preference. One consequence is that there is no universally attractive male phenotype. Only responsiveness shows significant additive genetic variation. Variation in responsiveness appears to mask variation in discrimination and some preference functions and may be the most biologically relevant source of phenotypic and genetic variation in mate-choice behavior. To test the potential evolutionary importance of the phenotypic variation in mate choice that we report, we estimated the opportunity for and the intensity of sexual selection under models of mate choice that excluded and that incorporated individual female variation. We then compared these estimates with estimates based on measured mating success. Incorporating individual variation in mate choice generally did not predict the outcome of sexual selection any better than models that ignored such variation.

Animals↗
PubMed2001

Direct and indirect sexual selection and quantitative genetics of male traits in guppies (Poecilia reticulata).

The ornamentation and displays on which sexual attractiveness and thus mating success are based may be complex and comprise several traits. Predicting the outcome of sexual selection on such complex phenotypes requires an understanding of both the direct operation of selection on each trait and the indirect consequences of selection operating directly on genetically correlated traits. Here we report the results of a quantitative genetic analysis of the ornamentation, sexual attractiveness, and mating success of male guppies (Poecilia reticulata). We analyze male ornamentation both from the point of view of single ornamental traits (e.g., the area of each color) and of composite measures of the way the entire pattern is likely to be perceived by females (e.g., the mean and contrast in chroma). We demonstrate that there is substantial additive genetic variation in almost all measures of male ornamentation and that much of this variation may be Y linked. Attractiveness and mating success are positively correlated at the phenotypic and genetic level. Orange area and chroma, the area of a male's tail, and the color contrast of his pattern overall are positively correlated with attractiveness and/or mating success at the phenotypic and genetic levels. Using attractiveness and mating success as measures of fitness, we estimate gradients of linear directional sexual selection operating on each male trait and use equations of multivariate evolutionary change to predict the response of male ornamentation to this sexual selection. From these analyses, we predict that indirect selection may have important effects on the evolution of male guppy color patterns.

Animals↗