The Cross Flow Filtration Concept Used as a Deinking Method

The cross-flow filter was used to deink a 70% news and 30% coated section furnish. This has never been attempted before so the main objective was to determine if it would work. The secondary objective was to find the highest operating consistency possible. The filter can be used to remove ink, fines and filler from a stock suspension. The feed, accept and effluent samples were analyzed for percent ash, brightness, clark classification, Kajanni fiber length analysis and image analysis. The effluent had a 29.81% ash compared to the feed ash of 8.32%. The accept brightness was 42.9 while the feed brightness was 41.0. Image analysis showed that there were more ink particles per oven dry fiber in the effluent than in the feed or accepts. It also determined that the mean particle diameter in the effluent was 6.26 microns while the feed was 6.18 microns. The cross-flow filter was effective in removing ink and filler. One percent consistency was the highest operating consistency due to pump limitations. The cross-flow filtration concept has a great potential as a deinking method. Further work should be conducted to look at the screen design, stock temperature and feed consistency. Theoretically this device could be operated at any consistency if turbulent flow could be maintained

A Havelock source panel method for near-surface submarines

A panel method is described for calculating potential flow around near-surface submarines. The method uses Havelock sources which automatically satisfy the linearized free-surface boundary condition. Outputs from the method include pressure field, pressure drag, wave resistance, vertical force, trim moment and wave pattern. Comparisons are made with model tests for wave resistance of Series 58 and DARPA SUBOFF hulls, as well as with wave resistance, lift force and trim moment of three length-to-diameter variants of the DSTO Joubert submarine hull. It is found that the Havelock source panel method is capable of determining with reasonable accuracy wave resistance, vertical force and trim moment for submarine hulls. Further experimental data are required in order to assess the accuracy of the method for pressure field and wave pattern prediction. The method is implemented in the computer code “HullWave” and offers potential advantages over RANS-CFD codes in terms of speed, simplicity and robustness

Development of a diagnostic sensor for measuring blood cell concentrations during haemoconcentration

Background: HemoSep® is a commercial ultrafiltration and haemoconcentration device for the concentration of residual bypass blood following surgery. This technology is capable of reducing blood loss in cardiac and other types of "clean site" procedures, including paediatric surgery. Clinical feedback suggested that the device would be enhanced by including a sensor technology capable of discerning the concentration level of the processed blood product. We sought to develop a novel sensor that can, using light absorption, give an accurate estimate of packed cell volume (PCV). Materials and methods: A sensor-housing unit was 3D printed and the factors influencing the sensor's effectiveness – supply voltage, sensitivity and emitter intensity - were optimised. We developed a smart system, using comparator circuitry capable of visually informing the user when adequate PCV levels (⩾35%) are attained by HemoSep® blood processing, which ultimately indicates that the blood is ready for autotransfusion. Results: Our data demonstrated that the device was capable of identifying blood concentration at and beyond the 35% PCV level. The device was found to be 100% accurate at identifying concentration levels of 35% from a starting level of 20%. Discussion: The sensory capability was integrated into HemoSep's® current device and is designed to enhance the user’s clinical experience and to optimise the benefits of HemoSep® therapy. The present study focused on laboratory studies using bovine blood. Further studies are now planned in the clinical setting to confirm the efficacy of the device

Lessons from a large scale deployment of DGT in the Seine basin

Diffusive Gradient in Thin film (DGT) is a speciation technique now commonly used in the scientific literature to assess metallic contamination in water. However applications usually take place in a same watercourse or in neighbouring sites. We propose here to present the first results of a large scale deployment of DGTs. The main objective of the project, which is supported by the French water agency of the Seine-Normandie basin, is to evaluate the potential of passive samplers as monitoring tools. DGT devices were deployed in 45 sites, on 30 locations in the entire Seine river basin. The sampling area was 500 km long and 200 km wide around Paris. The total sampling period lasted over the whole 2009 year. Restricted gels of 0.78 were used to measure labile Cd, Cr, Co, Cu, Mn, Ni, Pb and Zn. In parallel, raw and filtered water samples were collected to measure total and dissolved metals. General physico-chemical parameters were also measured. The whole set of measurements constitute a rich dataset including large and small rivers, and reference as well as impacted sites. The results first allow us to draw a map of total, dissolved and labile metal concentrations, representing the spatial variability of metal contamination in the Seine basin. Moreover, considering the temporal variability, different behaviours, depending on the metal, can be identified. The large scale deployment of DGT in the Seine river basin was successful: all the samples have been interpreted and are exploitable, whereas the dissolved metal samples are sometimes under the detection limit. We have then built a representative data set on the water contamination in labile metal of an urban impacted basin. The results are also interpreted as labile percentage, showing the operationally possible values of lability in contrasted environmental conditions. A first approach of the factors influencing the lability highlights the significance of the nature of the organic matter to interpret the lability of the metals

Differential binding patterns of anti-sulfatide antibodies to glial membranes

Sulfatide is a major glycosphingolipid in myelin and a target for autoantibodies in autoimmune neuropathies. However neuropathy disease models have not been widely established, in part because currently available monoclonal antibodies to sulfatide may not represent the diversity of anti-sulfatide antibody binding patterns found in neuropathy patients. We sought to address this issue by generating and characterising a panel of new anti-sulfatide monoclonal antibodies. These antibodies have sulfatide reactivity distinct from existing antibodies in assays and in binding to peripheral nerve tissues and can be used to provide insights into the pathophysiological roles of anti-sulfatide antibodies in demyelinating neuropathies

One step multiderivative methods for first order ordinary differential equations

A family of one-step multiderivative methods based on Padé approximants to the exponential function is developed. The methods are extrapolated and analysed for use in PECE mode. Error constants and stability intervals are calculated and the combinations compared with well known linear multi-step combinations and combinations using high accuracy Newton-Cotes quadrature formulas as correctors. w926020

Patient-specific blood flow simulations in the pulmonary bifurcation of patients with tetralogy of fallot

Dysfunction of the pulmonary valve and narrowing of the branch pulmonary arteries are common chronic complications in adult patients with tetralogy of Fallot; the most common cyanotic congenital heart disease with an estimate prevalence 1 in 3000 live births. Clinical consequences include, but are not limited to, abnormal lung development and elevated pulmonary vascular resistance. It is, therefore, crucial to better understand and characterise the haemodynamic environment in the pulmonary bifurcation to better diagnose and treat these patients. In this study, we have focused on investigating the blood flow dynamics in patient-specific geometries of the pulmonary bifurcation by means of computational models

Dynamical effects induced by long range activation in a nonequilibrium reaction-diffusion system

We both show experimentally and numerically that the time scales separation introduced by long range activation can induce oscillations and excitability in nonequilibrium reaction-diffusion systems that would otherwise only exhibit bistability. Namely, we show that the Chlorite-Tetrathionate reaction, where autocatalytic species diffuses faster than the substrates, the spatial bistability domain in the nonequilibrium phase diagram is extended with oscillatory and excitability domains. A simple model and a more realistic model qualitatively account for the observed behavior. The latter model provides quantitative agreement with the experiments.Comment: 19 pages + 9 figure

Learning from Lockdown: Listening to students' voices about the challenges and benefits in the post-COVID-19 digital practices

The sudden move to remote teaching and learning in Spring 2020 brought together staff and students in order to learn from each other how to best address the challenges of the new ways of teaching and learning. In this synchronous presentation the seven authors will take turns: *to introduce the two institutionally-supported studies conducted last year, one surveying the UCL undergraduates, and the other one surveying the postgraduate taught students in the CPA department of UCL IoE; *to share the framework that guided the analysis of students’ views of their experiences and priorities surrounding online learning, gathered via online surveys and focussed group discussions; *to propose alternative conceptions for what could be a meaningful and rich online educative experience; *to discuss our findings and their implications for theory, research, policy and practice in a post-pandemic context; and last and most important, *to describe how staff and students collaborated on carrying out these projects, and later worked together to write an academic paper about to the two projects

Cellulose production is coupled to sensing of the pyrimidine biosynthetic pathway via c-di-GMP production by the DgcQ protein of Escherichia coli

Production of cellulose, a stress response-mediated process in enterobacteria, is modulated in Escherichia coli by the activity of the two pyrimidine nucleotide biosynthetic pathways, namely, the de novo biosynthetic pathway and the salvage pathway, which relies on the environmental availability of pyrimidine nitrogenous bases. We had previously reported that prevalence of the salvage over the de novo pathway triggers cellulose production via synthesis of the second messenger c-di-GMP by the DgcQ (YedQ) diguanylate cyclase. In this work, we show that DgcQ enzymatic activity is enhanced by UTP, whilst being inhibited by N-carbamoyl-aspartate, an intermediate of the de novo pathway. Thus, direct allosteric control by these ligands allows full DgcQ activity exclusively in cells actively synthesizing pyrimidine nucleotides via the salvage pathway. Inhibition of DgcQ activity by N-carbamoyl-aspartate appears to be favoured by protein-protein interaction between DgcQ and PyrB, a subunit of aspartate transcarbamylase, which synthesizes N-carbamoyl-aspartate. Our results suggest that availability of pyrimidine bases might be sensed, somehow paradoxically, as an environmental stress by E. coli. We hypothesize that this link might have evolved since stress events, leading to extensive DNA/RNA degradation or lysis of neighbouring cells, can result in increased pyrimidine concentrations and activation of the salvage pathway