University of Sheffield

About: University of Sheffield is a education organization based out in Sheffield, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 41675 authors who have published 102908 publications receiving 3946383 citations. The organization is also known as: Sheffield University & shef.ac.uk.

Quality-of-life measures in chronic diseases of childhood

Abstract: Scope of the report This report is concerned with the evaluation of measures broadly designed to measure quality of life (QoL) in children and adolescents, either by self-report or proxy raters. Four research questions were identified: (1) To what extent are adult measures used in the evaluation of healthcare interventions in children? (2) How appropriate are adult measures for use with children? (3) To what extent do child self-reports correspond with assessments made by parents and carers? (4) How feasible and reliable are proxy measures of QoL in different disease contexts? Objectives (1) To review the state of the art with regard to measurement of QoL for children. (2) To make recommendations regarding the value of currently available measures for different purposes. (3) To identify further research needs. Method Electronic databases were searched for the period 1980-July 1999 for articles relating to measures of QoL, health status or well-being in children (under 18 years) with chronic disease. Handsearching of relevant journals and cross-referencing with reference lists in identified articles was also carried out. Key workers in the field were contacted for additional information, and the Internet was searched for relevant websites. Results Forty-three measures were identified (19 generic and 24 disease-specific). Sixteen measures allowed for completion by children and parent/caregiver; seven only allowed for completion by a proxy, and the remainder (n = 17) allowed only for child completion. The measures were described as QoL (n = 30), health status, (n = 2), perception of illness (n = 1), life satisfaction (n = 1) and quality of well-being (n = 1). RESULTS - TO WHAT EXTENT ARE ADULT MEASURES USED IN THE EVALUATION OF HEALTHCARE INTERVENTIONS IN CHILDREN?: Three studies were identified where adult measures were used with very few changes made for children. In 11 studies involving nine separate measures of QoL, adult measures were used as a model for work with children. RESULTS - HOW APPROPRIATE ARE ADULT MEASURES FOR USE WITH CHILDREN?: Adult measures may fail to tap the specific aspects of QoL that are important to the child. Measures based on adult work impose considerable response burden for children, in terms of length, reading skills and response scale. Wording and format of adult measures may need to be modified to account for children's cognitive and language skills. More basic research is needed to determine the level of response burden that children of different ages can manage. Assessments of difficulty (e.g. reading age) need to be routinely included with information about new measures. RESULTS - TO WHAT EXTENT DO CHILD SELF-REPORTS CORRESPOND WITH ASSESSMENTS MADE BY PARENTS AND CARERS?: Fourteen studies were identified in which concor-dance between child and parent was investigated, often as part of the development of a new measure. There was some evidence for greater concordance between child and parent for physical functioning compared with social and emotional domains, but greater heterogeneity in the latter measures may contribute to inconsistent results. There was no simple relationship between concordance and moderating variables such as age, gender and illness, but this conclusion was addressed only very rarely. RESULTS - HOW FEASIBLE AND RELIABLE ARE PROXY MEASURES OF QOL IN DIFFERENT DISEASE CONTEXTS?: Only five papers fulfilled the review criteria. Evaluation is difficult because authors fail to justify their choice of measures, and do not report critical information such as completion rates or missing data. Use of existing measures can potentially eliminate the time and expense required to develop a comprehensive measure of QoL, but a full battery of standardised tests may be expensive in terms of time for administration and scoring. In addition, battery measures tend to be lengthy and therefore demanding for sick patients. They are not recommended for work with children. RECOMMENDATIONS FOR RESEARCH - MINIMUM CRITERIA FOR NEW MEASURES: A set of procedures needs to be established for the development of new measures. These need to draw on the experience gained in development of child and adult measures to date. Basic research to enhance understanding of how children interpret questions in QoL measures is recommended. We need to understand the differences in meaning of items between children and adults, and between children of different ages. Some attempt to develop measures for children of 6 years or more have been reported, and these should be further developed. (ABSTRACT TRUNCATED)

The PINK1/Parkin pathway regulates mitochondrial morphology

Abstract: Loss-of-function mutations in the PTEN-induced kinase 1 (PINK1) or parkin genes, which encode a mitochondrially localized serine/threonine kinase and a ubiquitin-protein ligase, respectively, result in recessive familial forms of Parkinsonism. Genetic studies in Drosophila indicate that PINK1 acts upstream of Parkin in a common pathway that influences mitochondrial integrity in a subset of tissues, including flight muscle and dopaminergic neurons. The mechanism by which PINK1 and Parkin influence mitochondrial integrity is currently unknown, although mutations in the PINK1 and parkin genes result in enlarged or swollen mitochondria, suggesting a possible regulatory role for the PINK1/Parkin pathway in mitochondrial morphology. To address this hypothesis, we examined the influence of genetic alterations affecting the machinery that governs mitochondrial morphology on the PINK1 and parkin mutant phenotypes. We report that heterozygous loss-of-function mutations of drp1, which encodes a key mitochondrial fission-promoting component, are largely lethal in a PINK1 or parkin mutant background. Conversely, the flight muscle degeneration and mitochondrial morphological alterations that result from mutations in PINK1 and parkin are strongly suppressed by increased drp1 gene dosage and by heterozygous loss-of-function mutations affecting the mitochondrial fusion-promoting factors OPA1 and Mfn2. Finally, we find that an eye phenotype associated with increased PINK1/Parkin pathway activity is suppressed by perturbations that reduce mitochondrial fission and enhanced by perturbations that reduce mitochondrial fusion. Our studies suggest that the PINK1/Parkin pathway promotes mitochondrial fission and that the loss of mitochondrial and tissue integrity in PINK1 and parkin mutants derives from reduced mitochondrial fission.

Polymerization-Induced Self-Assembly of Block Copolymer Nano-objects via RAFT Aqueous Dispersion Polymerization

Abstract: In this Perspective, we discuss the recent development of polymerization-induced self-assembly mediated by reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization. This approach has quickly become a powerful and versatile technique for the synthesis of a wide range of bespoke organic diblock copolymer nano-objects of controllable size, morphology, and surface functionality. Given its potential scalability, such environmentally-friendly formulations are expected to offer many potential applications, such as novel Pickering emulsifiers, efficient microencapsulation vehicles, and sterilizable thermo-responsive hydrogels for the cost-effective long-term storage of mammalian cells.

The Spread of Plastic Yield from a Notch

Abstract: A calculation is made of the length of plastic zone needed to accommodate a given plastic displacement at the root of a notch in a uniformly stressed solid. In an optimum range of stress this zone is about 1000 times larger than the plastic displacement and about five times longer than the notch. The distribution of plastic-elastic strain in the yielded region can be represented by an inverted pile-up of dislocations. The results are related to the problem of notch-brittleness in steel and it is concluded that a condition of `far-reaching' yield should replace the condition of general yield for starting a fracture. Various factors important to notch-brittleness are briefly discussed.

Smoking and fracture risk: a meta-analysis

Abstract: Smoking is widely considered a risk factor for future fracture. The aim of this study was to quantify this risk on an international basis and to explore the relationship of this risk with age, sex and bone mineral density (BMD). We studied 59,232 men and women (74% female) from ten prospective cohorts comprising EVOS/EPOS, DOES, CaMos, Rochester, Sheffield, Rotterdam, Kuopio, Hiroshima and two cohorts from Gothenburg. Cohorts were followed for a total of 250,000 person-years. The effect of current or past smoking, on the risk of any fracture, any osteoporotic fracture and hip fracture alone was examined using a Poisson model for each sex from each cohort. Covariates examined were age, sex and BMD. The results of the different studies were merged using the weighted beta-coefficients. Current smoking was associated with a significantly increased risk of any fracture compared to non-smokers (RR=1.25; 95% Confidence Interval (CI)=1.15-1.36). Risk ratio (RR) was adjusted marginally downward when account was taken of BMD, but it remained significantly increased (RR=1.13). For an osteoporotic fracture, the risk was marginally higher (RR=1.29; 95% CI=1.13-1.28). The highest risk was observed for hip fracture (RR=1.84; 95% CI=1.52-2.22), but this was also somewhat lower after adjustment for BMD (RR=1.60; 95% CI=1.27-2.02). Risk ratios were significantly higher in men than in women for all fractures and for osteoporotic fractures, but not for hip fracture. Low BMD accounted for only 23% of the smoking-related risk of hip fracture. Adjustment for body mass index had a small downward effect on risk for all fracture outcomes. For osteoporotic fracture, the risk ratio increased with age, but decreased with age for hip fracture. A smoking history was associated with a significantly increased risk of fracture compared with individuals with no smoking history, but the risk ratios were lower than for current smoking. We conclude that a history of smoking results in fracture risk that is substantially greater than that explained by measurement of BMD. Its validation on an international basis permits the use of this risk factor in case finding strategies.