Opthalmic impairment at 7 years of age in children born very preterm

Aims: To determine the prevalence of ophthalmic impairments in very preterm compared with term infants, the relation between impairments and cerebral ultrasound appearances and retinopathy, and the correlation with visual perception and motor and cognitive measures. Subjects: 279 children at 7 years of age born before 32 weeks gestation within Liverpool during 1991–92 and attending mainstream schools, and 210 term controls. Methods: Visual acuity was assessed by Snellen chart, and strabismus by the cover test. Stereopsis was determined using the TNO random dot test, and contrast sensitivity using the Cambridge low contrast gratings. Visual and motor abilities were assessed using the Developmental test of motor integration (VMI) and the Movement ABC. Intelligence was measured with the Wechsler intelligence scale for children UK. Perinatal cranial ultrasound and retinopathy data were extracted from clinical records. Results: Children born preterm were significantly more likely to wear glasses, to have poor visual acuity, reduced stereopsis, and strabismus than term controls, but they showed no significant decrease in contrast sensitivity. Ophthalmic impairments were significantly related to poorer scores on the VMI, Movement ABC, and Wechsler IQ tests, but were not significantly related to neonatal cranial ultrasound appearances. Stage 3 retinopathy was related to poorer subsequent acuity. Conclusions: Children born very preterm and without major neurodevelopmental sequelae have an increased prevalence of ophthalmic impairments at primary school age which are associated with visual perceptional, motor, and cognitive defects. The cause may be a generalised abnormality of cortical development rather than perinatally acquired focal lesions of the brain

Achilles tendon (3D): Do the mechanical properties of tendon change in response to exercise?

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recor

Widespread association between the ericoid mycorrhizal fungus Rhizoscyphus ericae and a leafy liverwort in the maritime and sub-Antarctic

A recent study identified a fungal isolate from the Antarctic leafy liverwort Cephaloziella varians as the ericoid mycorrhizal associate Rhizoscyphus ericae. However, nothing is known about the wider Antarctic distribution of R. ericae in C. varians, and inoculation experiments confirming the ability of the fungus to form coils in the liverwort are lacking. Using direct isolation and baiting with Vaccinium macrocarpon seedlings, fungi were isolated from C. varians sampled from eight sites across a 1875-km transect through sub- and maritime Antarctica. The ability of an isolate to form coils in aseptically grown C. varians was also tested. Fungi with 98–99% sequence identity to R. ericae internal transcribed spacer (ITS) region and partial large subunit ribosomal (r)DNA sequences were frequently isolated from C. varians at all sites sampled. The EF4/Fung5 primer set did not amplify small subunit rDNA from three of five R. ericae isolates, probably accounting for the reported absence of the fungus from C. varians in a previous study. Rhizoscyphus ericae was found to colonize aseptically-grown C. varians intracellularly, forming hyphal coils. This study shows that the association between R. ericae and C. varians is apparently widespread in Antarctica, and confirms that R. ericae is at least in part responsible for the formation of the coils observed in rhizoids of field-collected C. varians

Observational consequences of the hypothesized helium rich stellar population in Omega Centauri

In response to the proposed high helium content stars as an explanation for the double main sequence observed in Omega Centauri, we investigated the consequences of such stars elsewhere on the color-magnitude diagram. We concentrated on the horizontal branch where the effects of high helium are expected to show themselves more clearly. In the process, we developed a procedure for comparing the mass loss suffered by differing stellar populations in a physically motivated manner. High helium stars in the numbers proposed seem absent from the horizontal branch of Omega Centauri unless their mass loss history is very different from that of the majority metal-poor stars. It is possible to generate a double main sequence with existing Omega Centauri stars via accretion of helium rich pollution consistent with the latest AGB ejecta theoretical yields, and such polluted stars are consistent with the observed HB morphology of Omega Centauri. Polluted models are consistent with observed merging of the main sequences as opposed to our models of helium rich stars. Using the (B-R)/(B+V+R) statistic, we find that the high helium bMS stars require an age difference compared to the rMS stars that is too great, whereas the pollution scenario stars have no such conflict for inferred Omega Centauri mass losses.Comment: 37 pages, 10 figures, accepted for publication in Ap

Microbial community drivers of PK/NRP gene diversity in selected global soils

Background The emergence of antibiotic-resistant pathogens has created an urgent need for novel antimicrobial treatments. Advances in next-generation sequencing have opened new frontiers for discovery programmes for natural products allowing the exploitation of a larger fraction of the microbial community. Polyketide (PK) and non-ribosomal pepetide (NRP) natural products have been reported to be related to compounds with antimicrobial and anticancer activities. We report here a new culture-independent approach to explore bacterial biosynthetic diversity and determine bacterial phyla in the microbial community associated with PK and NRP diversity in selected soils. Results Through amplicon sequencing, we explored the microbial diversity (16S rRNA gene) of 13 soils from Antarctica, Africa, Europe and a Caribbean island and correlated this with the amplicon diversity of the adenylation (A) and ketosynthase (KS) domains within functional genes coding for non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), which are involved in the production of NRP and PK, respectively. Mantel and Procrustes correlation analyses with microbial taxonomic data identified not only the well-studied phyla Actinobacteria and Proteobacteria, but also, interestingly, the less biotechnologically exploited phyla Verrucomicrobia and Bacteroidetes, as potential sources harbouring diverse A and KS domains. Some soils, notably that from Antarctica, provided evidence of endemic diversity, whilst others, such as those from Europe, clustered together. In particular, the majority of the domain reads from Antarctica remained unmatched to known sequences suggesting they could encode enzymes for potentially novel PK and NRP. Conclusions The approach presented here highlights potential sources of metabolic novelty in the environment which will be a useful precursor to metagenomic biosynthetic gene cluster mining for PKs and NRPs which could provide leads for new antimicrobial metabolites

Amblyopia and quality of life: a systematic review

Background/Aims Amblyopia is a common condition which can affect up to 5% of the general population. The health-related quality of life (HRQoL) implications of amblyopia and/or its treatment have been explored in the literature. Methods A systematic literature search was undertaken (16th-30th January 2007) to identify the HRQoL implications of amblyopia and/or its treatment. Results A total of 25 papers were included in the literature review. The HRQoL implications of amblyopia related specifically to amblyopia treatment, rather than the condition itself. These included the impact upon family life; social interactions; difficulties undertaking daily activities; and feelings and behaviour. The identified studies adopted a number of methodologies. The study populations included; children with the condition; parents of children with amblyopia; and adults who had undertaken amblyopia treatment as a child. Some studies developed their own measures of HRQoL, and others determined HRQoL through proxy measures. Conclusions The reported findings of the HRQoL implications are of importance when considering the management of cases of amblyopia. Further research is required to assess the immediate and long-term effects of amblyopia and/or its treatment upon HRQoL using a more standardised approach

Visual risk factors for falls in older adults: a case-control study

Background: Falls are the second leading  cause of accidental deaths worldwide mainly in older people. Older people have poor vision and published evidence suggests that it is a risk factor for falls. Less than half of falls clinics assess vision as part of the multi-factorial assessment of older adults at risk of falls despite vision being an essential input for postural stability. The aim of our study was to investigate the relationship between all clinically assessed visual functions and falls amongst older adults in a prospective observational individually age-matched case control study. Methods: Visual acuity (VA), contrast sensitivity (CS), depth perception, binocular vision and binocular visual field were measured using routinely used clinical methods in falls participants (N = 83) and non-falls participants (N = 83). Data were also collected on socio-demographic factors, general health, number of medications, health quality, fear of falling and physical activity. Logistic regression analysis was carried out to determine key visual and non-visual risk factors for falls whilst adjusting for confounding covariates. Results: Older adults have an increased risk of experiencing a fall if they have reduced visual function (odds ratio (OR): 3.49, 1.64-7.45, p = 0.001), specifically impaired stereoacuity worse than 85” of arc (OR: 3.4, 1.20-9.69, p = 0.02) and reduced (by 0.15 log unit) high spatial frequency CS (18 cpd) (OR:1.40, 1.12-1.80, p = 0.003). Older adults with a hearing impairment are also at higher risk of falls (OR: 3.18, 95% CI: 1.36-7.40, p = 0.007). The risk decreases with living in a less deprived area (OR: 0.74, 0.64-0.86, <0.001), or socialising more out of the home (OR: 0.75, 0.60-0.93, p = 0.01). Conclusions: The combination of social, behavioural and biological determinants are significant predictors of a fall. The non-visual risk factors include older adults, living in deprived neighbourhoods, socialising less outside of the home and those who have a hearing impairment. Impaired functional visual measures; depth perception and contrast are significant visual risk factors for falls above visual acuity

Studies of Breakdown in a Pressurized RF Cavity

Microscopic images of the surfaces of metallic electrodes used in high-pressure gas-filled 805 MHz RF cavity experiments [1] have been used to investigate the mechanism of RF breakdown [2]. The images show evidence for melting and boiling in small regions of ∼10 micron diameter on tungsten, molybdenum, and beryllium electrode surfaces. In these experiments, the dense hydrogen gas in the cavity prevents electrons or ions from being accelerated to high enough energy to participate in the breakdown process so that the only important variables are the fields and the metallic surfaces. The distributions of breakdown remnants on the electrode surfaces are compared to the maximum surface gradient E predicted by an ANSYS model of the cavity. The local surface density of spark remnants, proportional to the probability of breakdown, shows a strong exponential dependence on the maximum gradient, which is reminiscent of Fowler-Nordheim behavior of electron emission from a cold cathode. New simulation results have shown good agreement with the breakdown behaviour of the hydrogen gas in the Paschen region and have suggested improved behaviour with the addition of trace dopants such as SF6 [3]. Present efforts are to extend the computer model to include electrode breakdown phenomena and to use scanning tunnelling microscopy to search for work function differences between the conditioned and unconditioned parts of the electrodes

Evaluation of the Workplace Environment in the UK, and the Impact on Users’ Levels of Stimulation

The purpose of this study is to evaluate a number of recently completed workplaces in the UK. The first aim is to assess the impact of various aspects of the workplace environment on users’ levels of stimulation. The body of previous research undertaken into the workplace environment, identified the aspects to be investigated. Samples of employees from the sixteen businesses were surveyed to determine their perceptions of the workplaces. The results were entered into a regression analysis, and the most significant predictors of perceived stimulation identified. The data also revealed a dramatic reduction in staff arousal levels from mornings to afternoons. Thus, there is a second aim to determine whether changes to significant aspects of the workplace environment during the day can counteract the reduction in users’ stimulation. Two further workplaces were studied to enable changes to be made over a 12-week period. A sample of employees completed questionnaires, and semi-structured interviews revealed the reasons behind the results. It was found that provision of artwork, personal control of temperature and ventilation and regular breaks were the most significant contributions to increasing stimulation after lunch; while user choice of layout, and design and décor of workspaces and break areas, were the most significant aspects at design stage