Local and global trace plutonium contributions in fast breeder legacy soils

Trace-level plutonium in the environment often comprises local and global contributions, and is usually anthropogenic in origin. Here, we report estimates of local and global contributions to trace-level plutonium in soil from a former, fast-breeder reactor site. The measured ²⁴⁰Pu/²³⁹Pu ratio is anomalously low, as per the reduced ²⁴⁰Pu yield expected in plutonium bred with fast neutrons. Anomalies in plutonium concentration and isotopic ratio suggest forensic insight into specific activities on site, such as clean-up or structural change. Local and global ²³⁹Pu contributions on-site are estimated at (34 ± 1)% and (66 ± 3)%, respectively, with mass concentrations of (183 ± 6) fg g^-1 and (362 ± 13) fg g^-1. The latter is consistent with levels at undisturbed and distant sites, (384 ± 44) fg g^-1, where no local contribution is expected. The ²⁴⁰Pu/²³⁹Pu ratio for site-derived material is estimated at 0.05 ± 0.04. Our study demonstrates the multi-faceted potential of trace plutonium assay to inform clean-up strategies of fast breeder legacies.

Plutonium and Americium Inventories in Soil Cores from the English Lake District, Cumbria (UK)

Environmental radioactivity has been reported in the stationary wetlands closer to the natural water basins in Great Britain, precisely in the English Lake District (Cumbria, UK) often emphasise on the investigation carried out through either high-resolution γ-ray spectroscopy or α-particle spectroscopy. The objective of the study is the evaluation of trace actinide (241Am) through environments radioactivity measurements of two Lakes in the Lake District using a broad-energy, high-resolution γ-ray spectroscopy germanium (BEGe) detector. These appeal to the need to determine the radioactive concentration (Bq/g) in the soil samples with the intent being to discern natural and anthropogenic contributions, and trends in abundances associated with influences of the landscape over time, at trace levels in the environment. These measurements highlight potential benefits for the assessment of 241Am and 241Pu, especially comparisons that might be made with accelerator mass spectrometry assessments (AMS). This study intents to offer an inclusive investigation practise for determining the levels of radioactivity in soil cores, as well as the method for statistical analysis approach to calculate the activity of a soil sample, with a special emphasis on categorising the natural and anthropogenic contributors to trace amounts of plutonium in the environment, that is, less than500 fg/g.

Highly sensitive ZnO nanorod- and nanoprism-based NO2 gas sensors: size and shape control using a continuous hydrothermal pilot plant

Continuous hydrothermal flow synthesis of crystalline ZnO nanorods and prisms is reported via a new pilot-scale continuous hydrothermal reactor (at nominal production rates of up to 1.2 g/h). Different size and shape particles of ZnO (wurtsite structure) were obtained via altering reaction conditions such as the concentration of either additive H2O2 or metal salt. Selected ZnO samples (used as prepared) were evaluated as solid oxide gas sensors, showing excellent sensitivity toward NO2 gas. It was found that both the working temperature and gas concentration significantly affected the NO2 gas response at concentrations as low as 1 ppm.

Decision-making by parents and children in paediatric hand surgery

The task of decision-making about microvascular toe-transfer surgery is a complex one for parents and their children. The process involves balancing risks and benefits within the context of the emotional responses of the parents and the future needs of their children. This paper describes a model of clinical practice which incorporates that process through a multi-disciplinary approach. The factors which influenced parents in their decision are examined, and the issue of the competence of the child to participate is discussed. 34 families were assessed, of whom 7 did not proceed with surgery. It was found that parents were more influenced by factors within the process, such as communication, than by concerns about technical outcome. Specialised psychological counselling played an integral role in the making of stable decisions.

The role of the musculature in injuries to the medial collateral ligament

With a knee-testing device we measured the valgus stiffness of the medial musculoligamentous complex of the knee in five volunteers. Tests were done with the muscles quiescent and with contraction of the sartorius and vastus medialis. Contraction of those muscles substantially increased the valgus stiffness. In eight subjects the voluntary reaction times were measured. With either a visual or a tactile impulse for prophylactic muscle contraction, the muscles acted too slowly to augment the stiffness of the knee so as to prevent injury. In fifty-one volunteers we applied the maximum torque to the leg, just short of eliciting pain, and showed that even then the muscle contraction would occur too late to protect the knee in typical sports situations.