Gamma spectrometry analysis of radioiodine in charcoal from high volume aerosol samples.

Following accidental releases, gamma spectrometry of impregnated charcoal filters is used to measure gaseous 131I contamination, but is subject to sampling inhomogeneity. In this study two germanium detectors are calibrated using a charcoal multi-gamma standard. Activities in samples spiked with a matrix of 131I aliquots are compared based on measurement, spike known activity, and monte-carlo simulation, and used to test a simple mixing method. Measurement efficiency, and removal of 11% inhomogeneity effect by mixing, was successfully reproduced in GESPECOR calculations.

An automated programme for the optimisation of HPGe detector parameters using an evolutionary algorithm with GESPECOR.

We describe the development of an automated, user-friendly programme which, making use of the GESPECOR gamma spectrometry software to conduct Monte Carlo simulations, yields an optimised model of a HPGe detector by applying suitable optimisation algorithms without requiring any further user intervention. The programme is capable of simultaneously employing multiple experimental FEP efficiency curves for the parameter optimisation process. Application of the optimisation process to a HPGe detector demonstrates that accurate, robust models can be achieved using this approach.

Airborne concentrations and chemical considerations of radioactive ruthenium from an undeclared major nuclear release in 2017.

In October 2017, most European countries reported unique atmospheric detections of aerosol-bound radioruthenium (106Ru). The range of concentrations varied from some tenths of µBq·m-3 to more than 150 mBq·m-3 The widespread detection at such considerable (yet innocuous) levels suggested a considerable release. To compare activity reports of airborne 106Ru with different sampling periods, concentrations were reconstructed based on the most probable plume presence duration at each location. Based on airborne concentration spreading and chemical considerations, it is possible to assume that the release occurred in the Southern Urals region (Russian Federation). The 106Ru age was estimated to be about 2 years. It exhibited highly soluble and less soluble fractions in aqueous media, high radiopurity (lack of concomitant radionuclides), and volatility between 700 and 1,000 °C, thus suggesting a release at an advanced stage in the reprocessing of nuclear fuel. The amount and isotopic characteristics of the radioruthenium release may indicate a context with the production of a large 144Ce source for a neutrino experiment.

Brief Report: Repetitive Behaviour Profiles in Williams syndrome: Cross Syndrome Comparisons with Prader-Willi and Down syndromes.

This study describes the profile of repetitive behaviour in individuals with Williams syndrome, utilising cross-syndrome comparisons with people with Prader-Willi and Down syndromes. The Repetitive Behaviour Questionnaire was administered to caregivers of adults with Williams (n = 96), Prader-Willi (n = 103) and Down (n = 78) syndromes. There were few group differences, although participants with Williams syndrome were more likely to show body stereotypies. Individuals with Williams syndrome also showed more hoarding and less tidying behaviours than those with Down syndrome. IQ and adaptive ability were negatively associated with repetitive questioning in people with Williams syndrome. The profile of repetitive behaviour amongst individuals with Williams syndrome was similar to the comparison syndromes. The cognitive mechanisms underlying these behaviours in genetic syndromes warrant further investigation.

The prevalence and phenomenology of self-injurious and aggressive behaviour in genetic syndromes.

BACKGROUND: Self-injurious and aggressive behaviours are reported as components of some behavioural phenotypes but there are few studies comparing across syndrome groups. In this study we examined the prevalence of these behaviours and the associated person characteristics in seven genetic syndromes. METHODS: Questionnaire data on self-injury and aggression, mood, hyperactivity, autism spectrum disorder and repetitive behaviour were collected on Angelman (AS, n=104), Cornelia de Lange (CdLS, 101), Cri du Chat (CdCS, 58), Fragile X (FXS, 191), Lowe (LS, 56), Prader-Willi (PWS, 189) and Smith-Magenis (SMS, 42) syndromes. RESULTS: A significantly higher prevalence of self-injury was evident in CdCS, CdLS, FXS, PWS, LS and SMS. The prevalence of aggression was significantly heightened in AS and SMS. Self-injury was associated with repetitive and impulsive behaviour in CdLS, FXS, PWS and LS. Impulsivity and overactivity were significantly higher in those showing aggression across all syndrome groups. CONCLUSIONS: These data quantify the risk for self-injury and aggression in the syndromes studied with implications for early intervention. The associations between these behaviours and person characteristics both within and between syndromes warrant further research.

The association between repetitive behaviours, impulsivity and hyperactivity in people with intellectual disability.

BACKGROUND: There is a need for assessments of psychological difference and disorder in people who have more severe intellectual disability (ID). Hyperactivity and impulsivity are two behavioural domains of importance as they are correlated with self-injury and aggression and this alludes to a shared cognitive correlate of compromised behavioural inhibition. Additionally, compromised behavioural inhibition is demonstrably related to repetitive behaviour and the latter might be expected to be associated with impulsivity and hyperactivity. METHODS: The Activity Questionnaire (TAQ) was developed for this study. Three sub-scales with high levels of face validity were supported by factor analysis of the scoring of 755 intellectually disabled participants on the TAQ items. These sub-scales mapped onto the constructs of Overactivity, Impulsivity and Impulsive Speech. Test-retest, inter-rater reliability and internal consistency were robust. TAQ scores and scores on the Repetitive Behaviour Questionnaire (RBQ) were collected for a sample of 136 participants with varying degrees of ID. RESULTS: Scores on the TAQ at sub-scale and full-scale level were not related to level of adaptive functioning. There were significant positive associations between overactivity (TAQ) and stereotyped behaviour (RBQ), impulsivity (TAQ) and restricted preferences (RBQ), and impulsive speech (TAQ) and repetitive speech (RBQ). CONCLUSIONS: The TAQ is a reliable assessment of hyperactivity and impulsivity for people with ID with robust factor structure. Validity requires evaluation. The relationship between impulsivity and restricted preferences may result from a common cognitive impairment in inhibition, which may underpin these two classes of behaviour.

The use of plate heat exchangers in growing human fibroblasts.

A method of using plate exchange equipment for the culture of anchorage dependent cells is described. No special orientation of the plates is required and cells may be readily recovered for subsequent use in other culture vessels. The method offers certain advantages over existing systems.

The mass culture of human diploid fibroblasts in packed beds of glass beads.

A system is described in which human diploid fibroblasts or other anchorage dependent cells may be conveniently cultured. The method would appear to offer a solution to the problem of the mass culture of such cells for the purpose of producing biologicals such as interferon.