A study of cerium extraction by TBP and TODGA using a rotating diffusion cell

For the study of the coupled interfacial-mass transfer kinetics of, inter alia, TBP, TODGA, CyMe4-BTBP and CyMe4-BTPhen based solvent extraction processes, a new rotating diffusion cell (RDC) apparatus has been established at Lancaster University. RDC studies of Ce(IV)/TBP and Ce(III)/TODGA extraction systems have been undertaken in order to improve the understanding of the chemical and kinetic processes involved. In each case, an interesting dependency on local hydrodynamics at the solution phase boundary with results suggesting that the organic extractant molecules migrate into the aqueous phase in order to capture Ce

A small scale monitoring study for a range of pharmaceuticals in the River Foss catchment and comparison to concentrations in the River Nag, India: report of researcher exchange March 2018

The India-UK Water Centre (IUKWC) promotes cooperation and collaboration between the complementary priorities of NERC-MoES water security research. This report represents an overview of the activities and conclusions of a Junior Researcher Exchange undertaken at the University of York from 7th March 2018 - 27th March 2018 convened by Akanksha Singh Kachhawaha (CSIR-National Environmental Engineering Research Institute, India) and Dr Alistair B.A. Boxall (University of York, UK). It outlines the aims of the exchange, describes the programme and the activities developed to meet the objectives, and details the outputs generated, as well as the ongoing and future collaboration. Finally, it assesses the support received from the IUKWC through the Researcher Exchange Scheme. The present report is intended for India-UK Water Centre members and water security stakeholders

Markers for Characterization of Bone Marrow Multipotential Stromal Cells

Given the observed efficacy of culture-expanded multipotential stromal cells, also termed mesenchymal stem cells (MSCs), in the treatment of graft-versus host and cardiac disease, it remains surprising that purity and potency characterization of manufactured cell batches remains rather basic. In this paper, we will initially discuss surface and molecular markers that were proposed to serve as the indicators of the MSC potency, in terms of their proliferative potential or the ability to differentiate into desired lineages. The second part of this paper will be dedicated to a critical discussion of surface markers of uncultured (i.e., native) bone marrow (BM) MSCs. Although no formal consensus has yet been reached on which markers may be best suited for prospective BM MSC isolation, markers that cross-react with MSCs of animal models (such as CD271 and W8-B2/MSCA-1) may have the strongest translational value. Whereas small animal models are needed to discover the in vivo function on these markers, large animal models are required for safety and efficacy testing of isolated MSCs, particularly in the field of bone and cartilage tissue engineering

Operational management of trunk main discolouration risk

Despite significant on-going investment, water companies continue to receive an unacceptable number of discolouration related customer contacts. In this paper, data from intensive distribution system turbidity monitoring and cluster analysis of discolouration customer contacts indicate that a significant proportion of these contacts are due to material mobilising from the trunk main system, and operational flow increases are shown to have a higher discolouration risk than burst incidents. A trunk main discolouration incident highlighting this risk is discussed, demonstrating the need for pro-active trunk main risk assessments. To identify the source of the material event flow rates were modelled using the PODDS (prediction of discolouration in distribution systems) discolouration model. Best practice pro-active management is demonstrated in a case study where the PODDS model is used to implement managed incremental flow changes on a main with known discolouration risk with no discolouration impact to customers and significant cost savings

Uncertainties of size measurements in electron microscopy characterization of nanomaterials in foods

Electron microscopy is a recognized standard tool for nanomaterial characterization, and recommended by the European Food Safety Authority for the size measurement of nanomaterials in food. Despite this, little data have been published assessing the reliability of the method, especially for size measurement of nanomaterials characterized by a broad size distribution and/or added to food matrices. This study is a thorough investigation of the measurement uncertainty when applying electron microscopy for size measurement of engineered nanomaterials in foods. Our results show that the number of measured particles was only a minor source of measurement uncertainty for nanomaterials in food, compared to the combined influence of sampling, sample preparation prior to imaging and the image analysis. The main conclusion is that to improve the measurement reliability, care should be taken to consider replications and matrix removal prior to sample preparation

Impacts of water pH on the toxicity of fluoxetine on Daphnia magna: a multi-generational study

Fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI), has been widely prescribed as anti-depressant. While FLX has been frequently detected in surface waters, sediments and biota, only limited information is available on its in vivo toxicity, particularly in invertebrates, under changing water pH. In the present study, the ecotoxicity of FLX (pKa = 9.8) was investigated in different pH levels (6.8, 8.3, and 9.2) using Daphnia magna. Daphnia neonates ( (F0) were exposed to 0, solvent control, 31.3, 62.5, 125, 250, 500, or 1000 μg/L for 48 hr and its effects on survivals (EC20, 50 and 75) were determined. Moreover, Daphnia neonates (The first brood daphnids from the chronic tests were discarded and the second brood daphnids (F1) were employed for the multigenerational acute test within 12 hours. F1 neonates were further exposed to 0, solvent control, 31.3, 62.5, 125, 250, or 500 μg/L for 48 hr and their survivals (EC20, 50 and 75) were determined. F0 juveniles exposed to 0 or 55.6 μg/L at 10 d were measured for MDA. After 48 hr of F0 and F1 exposure, the EC50 significantly decreased (p < 0.05) at 6.17 μg/L of FLX at all tested pHs. Moreover, after 21 d F0 exposure, the reproduction showed an increasing trend until 55.6 μg/L and significantly decreased at 166.7 μg/L at pH 9.2. F1 neonates showed significantly decreased body length after 21 d exposure to 2.06, 6.17, 18.5 and 55.6 μg/L at pH 9.2. Malformation of F1 daphnids development was also observed at 2.06 μg/L to 500 μg/L. MDA concentration was also demonstrated increasing trends in all pHs and significantly increased at 55.6 μg/L at pH 6.8 and 9.2. Our observation clearly indicates that survival, reproduction, and growth performance in aquatic invertebrate can be adversely affected by FLX and the toxicity increases as water pH increases. A greater amount of uncharged ions from FLX has increased Reactive Oxidative Stress (ROS), MDA, by the ionic speciation at higher pH. Increased MDA concentration affected the mortality of F0 daphnids. Increased F1 daphnids population demonstrated significantly greater toxicity. As a result, the toxicity of FLX has increased acutely, chronically, and multigenerational effects by increasing pH levels. Consequences of longer-term exposure over multigenerations warrant further investigation

Impacts of compound properties and sediment characteristics on the sorption behaviour of pharmaceuticals in aquatic systems

Sorption is a key factor in determining the persistence, attenuation and bioavailability of sediment-associated contaminants. However, our understanding of the sorption behaviour of pharmaceuticals in sediments is poor. In this study, we investigated the sorption behaviour of a diverse set of pharmaceuticals in a range sediment types. Sorption affinity of pharmaceuticals for all sediments was found to increase in the order mefenamic acid <cimetidine <atenolol <amitriptyline <diltiazem. Comparison of the experimental observations with predictions from an existing model for estimating sorption revealed the model worked poorly for the study pharmaceuticals. Multiple linear regression analysis was therefore used to develop new models for estimating sorption of individual pharmaceuticals based on sediment properties. The analyses indicated that sorption is related to properties such as Log Dow of a compound in the sediment (lipophilicity corrected for the sediment pH), cation exchange capacity, clay%, organic carbon content and exchangeable Ca2+, although, with the exception of atenolol, robust relationships between sediment properties and sorption were not obtained. Overall, the results demonstrate how complex the processes are that drive the sorption of pharmaceuticals in sediments and highlight the need for generation of further experimental data and further model development work

Portable LED fluorescence instrumentation for the rapid assessment of potable water quality

Characterising the organic and microbial matrix of water are key issues in ensuring a safe potable water supply. Current techniques only confirm water quality retrospectively via laboratory analysis of discrete samples. Whilst such analysis is required for regulatory purposes, it would be highly beneficial to monitor water quality in-situ in real time, enabling rapid water quality assessment and facilitating proactive management of water supply systems. A novel LED-based instrument, detecting fluorescence peaks C and T (surrogates for organic and microbial matter, respectively), was constructed and performance assessed. Results from over 200 samples taken from source waters through to customer tap from three UK water companies are presented. Excellent correlation was observed between the new device and a research grade spectrophotometer (r 2 = 0.98 and 0.77 for peak C and peak T respectively), demonstrating the potential of providing a low cost, portable alternative fluorimeter. The peak C/TOC correlation was very good (r 2 = 0.75) at low TOC levels found in drinking water. However, correlations between peak T and regulatory measures of microbial matter (2 day/3 day heterotrophic plate counts (HPC), E. coli, and total coliforms) were poor, due to the specific nature of these regulatory measures and the general measure of peak T. A more promising correlation was obtained between peak T and total bacteria using flow cytometry. Assessment of the fluorescence of four individual bacteria isolated from drinking water was also considered and excellent correlations found with peak T (Sphingobium sp. (r 2 = 0.83); Methylobacterium sp. (r 2 = 1.0); Rhodococcus sp. (r 2 = 0.86); Xenophilus sp. (r 2 = 0.96)). It is notable that each of the bacteria studied exhibited different levels of fluorescence as a function of their number. The scope for LED based instrumentation for insitu, real time assessment of the organic and microbial matrix of potable water is clearly demonstrated

Towards the decontamination of plutonium contaminated bricks:Creation of a cerium-based simulant contamination system

There is a need for the decontamination of a number of plutonium-contaminated bricks encountered in a legacy BUTEX reprocessing plant on Sellafield site in the UK. Documentary review has indicated that the source of the contamination was a 8 mol dm -3 nitric acid process stream containing 10 mmol dm -3 of Pu in either the (III) or (IV) oxidation state. Here we have sought to emulate the behaviour of Pu(III) by treatment of fired clay brick surfaces with a solution of 10 mmol dm -3 Ce(III) nitrate in 8 mol dm -3 nitric acid. XRD, porosimetry and EDX measurements of the untreated bricks reveal them to be comprised of low porosity silica and aluminosilicate phases with a surface layer of a low-Si content Al-C-N oxide derived from the atmosphere of the kiln in which the bricks were fired. Depth profiling after an initial 6 week acid soak reveals that the acid penetrates <10 mm into the brick. SEM/EDX analysis reveals that acid treatment significantly roughens the brick surface due to dissolution the above described Al-C-N oxide layer. The EDX data also shows that virtually no Ce is retained as tenacious contamination at the brick surface; this may be due to a either a mass action/kinetic effect or taken to indicate that trivalent Ce(III) is less likely to absorb at the crystalline silica/aluminosilicate surface of the brick than its more easily hydrolysable tetravalent equivalent. Preliminary higher-resolution EDX analysis indicates that small quantities of Ce(III) can be detected in pores or cracks on the surface of acid-treated brick samples. This suggests that Ce(III) may be non-tenaciously sequestered into surface defects - and that a simple salt wash may be sufficient to remove it. Based on the above observations, potential decontamination strategies are discussed and future studies outlined

A purple patch for evidence-based health policy?

The global focus on nation states' responses to the COVID-19 pandemic has rightly highlighted the importance of science and evidence as the basis for policy action. Those with a lifelong passion for evidence-based policy (EBP) have lauded Australia's and other nations' policy responses to COVID-19 as a breakthrough moment for the cause. This article reflects on the complexity of the public policy process, the perspectives of its various actors, and draws on Alford's work on the Blue, Red and Purple zones to propose a more nuanced approach to advocacy for EBP in health. We contend that the pathway for translation of research evidence into routine clinical practice is relatively linear, in contrast to the more complex course for translation of evidence to public policy - much to the frustration of health researchers and EBP advocates. Cairney's description of the characteristics of successful policy entrepreneurs offers useful guidance to advance EBP and we conclude with proposing some practical mechanisms to support it. Finally, we recommend that researchers and policy makers spend more time in the Purple zone to enable a deeper understanding of, and mutual respect for, the unique contributions made by research, policy and political actors to sound public policy