Colloidal Systems Confined to Curved Surfaces

Surface curvature plays a vital role in many biological processes. Examples include the organising of proteins in cell membranes, the tiling of cells in epithelial layers and the growth of virus capsids. A major technological benefit of micro- and nanoscale curvature is that it can guide colloidal self-assembly, a property which is of major importance in fields such as drug-delivery, biosensor fabrication, and the development of meta-materials. Recent advances in fabrication techniques, such as 3D-printing, have made a rich library of geometries available to experimentalists and engineers seeking to realise these complex and fascinating systems. Here, we use bespoke simulations and theoretical models to study the effects of surface curvature on two-dimensional systems of isotropically attractive colloids. We identify four important properties: the finite but boundary-free area of closed surfaces, the minimum perimeter of a patch with a given area, the difference between the Euclidean and geodesic separation of points on the surface, and the frustration of the hexagonal lattice in regions of non-zero Gaussian curvature. We also show that competition between these effects produces a range of novel behaviours. Starting from the simplest example of a sphere, we show that surface curvature has a strong effect on the gas-liquid nucleation profile and the size of the critical nucleus, as well as destroying the equivalence of the canonical and grand canonical ensembles. Then, focussing on surfaces with non-uniform curvature, we use tori to demonstrate that the different thermodynamic phases are localised to specific regions of the surface, and the transitions between them involve the translation of the colloidal assemble. Finally, we investigate the cone, where there is no Gaussian curvature but the mean curvature varies. We find that surface curvature can stabilise chiral and achiral crystals, and the ground states depend on both the range of the potential and whether it acts through Euclidean space or along geodesics

Supporting Creative Confidence in a Musical Composition Workshop: Sound of Colour

This paper explores and illuminates the work in progress of the ‘Sound of Colour’, an interactive musical installation, used to introduce musical concepts to children. Participants work in a collaborative manner to throw, roll, spin and bounce, coloured balls (typically found in children’s ball pits) to create an original generative musical composition, whilst learning the basics of pitch and volume. Through qualitative analysis and observations, the research discusses how a playful, colour based table top interface, affects the way that children interact with basic fundamentals of music, and how the interface affects their creative confidence when learning musical concepts. This study provides insight into how children interact and engage with a physical musical interface, in comparison to other tangible interfaces (button based controllers and mobile devices). In particular, when these instruments are used in a workshop setting, the research reveals novel methods for interaction with children to encourage and open up access to music composition

Natural Resources Journal, Annual Reports 1960-1961

Annual Report for the School of Law for the period July 1, 1960 through June 30, 1961. The mention of Natural Resources Journal has been extracted from the full report, but was originally noted at the top of page three

Multitasking, working memory and remembering intentions

Multitasking refers to the performance of a range of tasks that have to be completed within a limited time period. it differs from dual task paradigms in that tasks are performed not in parallel, but by interleaving, switching from one to the other. it differs also from task switching paradigms in that the time scale is very much longer, multiple different tasks are involved, and most tasks have a clear end point. Multitasking has been studied extensively with particular sets of experts such as in aviation and in the military, and impairments of multitasking performance have been studied in patients with frontal lobe lesions. Much less is known as to how multitasking is achieved in healthy adults who have not had specific training in the necessary skills. This paper will provide a brief review of research on everyday multitasking, and summarise the results of some recent experiments on simulated everyday tasks chosen to require advance and on-line planning, retrospective memory, prospective memory, and visual, spatial and verbal short-term memory

The effects of antibiotic combination treatments on Pseudomonas aeruginosa tolerance evolution and coexistence with Stenotrophomonas maltophilia

Pseudomonas aeruginosa bacterium is a common pathogen of Cystic Fibrosis (CF) patients due to its ability to evolve resistance to antibiotics during treatments. While P. aeruginosa resistance evolution is well characterised in monocultures, it is less well understood in polymicrobial CF infections. Here, we investigated how exposure to ciprofloxacin, colistin, or tobramycin antibiotics, administered at sub-MIC doses alone and in combination, shaped the tolerance evolution of P. aeruginosa (PAO1 lab and clinical CF LESB58 strains) in the absence and presence of a commonly co-occurring species, Stenotrophomonas maltophilia. Increases in antibiotic tolerances were primarily driven by the presence of that antibiotic in the treatment. We observed a reciprocal cross-tolerance between ciprofloxacin and tobramycin, and when combined these antibiotics selected increased MICs for all antibiotics. Though the presence of S. maltophilia did not affect the tolerance or the MIC evolution, it drove P. aeruginosa into extinction more frequently in the presence of tobramycin due to its relatively greater innate tobramycin tolerance. In contrast, P. aeruginosa dominated and drove S. maltophilia extinct in most other treatments. Together, our findings suggest that besides driving high-level antibiotic tolerance evolution, sub-MIC antibiotic exposure can alter competitive bacterial interactions, leading to target pathogen extinctions in multi-species communities.Funding provided by: University of YorkCrossref Funder Registry ID: http://dx.doi.org/10.13039/100009001Award Number:See Methods in paper for collection. MIC values (MIC data.csv) derived from visual inspection of antibiotic growth measurements plotted as a growth curve. Optical density data has been blank-corrected, and in the case of the antibiotic growth measurements (Antibiotic growth data.csv) averaged over ≤3 technical replicates

Advances in Development of the Fission Product Extraction Process for the Separation of Cesium and Strontium from Spent Nuclear Fuel

The Fission Product Extraction (FPEX) Process is being developed as part of the United States Department of Energy Advanced Fuel Cycle Initiative for the simultaneous separation of cesium (Cs) and strontium (Sr) from spent light water reactor (LWR) fuel. Separation of the Cs and Sr will reduce the short-term heat load in a geological repository, and when combined with the separation of americium (Am) and curium (Cm), could increase the capacity of the geological repository by a factor of approximately 100. The FPEX process is based on two highly specific extractants: 4,4',(5')-Di-(t-butyldicyclo-hexano)-18-crown-6 (DtBuCH18C6) and Calix[4]arene-bis-(tert-octylbenzo-crown-6) (BOBCalixC6). The DtBuCH18C6 extractant is selective for strontium and the BOBCalixC6 extractant is selective for cesium. Results of flowsheet testing of the FPEX process with a simulated feed solution in 3.3-cm centrifugal contactors are detailed. Removal efficiencies, distribution coefficient data, coextraction of metals, and process hydrodynamic performance are discussed along with recommendations for future flowsheet testing with actual spent nuclear fuel

New Opportunities for Automated Pedestrian Performance Measures

Pedestrian safety is an important concern when evaluating intersections. Previous literature has shown that exclusive pedestrian phases improve safety, but at the expense of imposing greater pedestrian and motorist delay. However, outside of crash data, there are no easily implementable performance measures for pedestrians at traffic signals. This study proposes two performance metrics: (1) a time-to-jaywalk measure, and (2) the Conflict Occupancy Ratio (COR) for evaluating concurrent pedestrian signal phasing with turning vehicles. The COR quantifies conflicts between turning vehicles and pedestrians in the crosswalk. The COR is based upon a commercially deployed video detection system that correctly identified the presence of pedestrians to within two per cycle in this study. This performance is likely sufficient for the current application, but as the technology matures it will provide a scalable screening tool to identify intersections that have opportunities for capacity adjustments or warrant further direct field investigation

Peptide‐Based Coacervate‐Core Vesicles with Semipermeable Membranes

Coacervates droplets have long been considered as potential protocells to mimic living cells. However, these droplets lack a membrane and are prone to coalescence, limiting their ability to survive, interact, and organize into higher-order assemblies. This work shows that tyrosine-rich peptide conjugates can undergo liquid–liquid phase separation in a well-defined pH window and transform into stable membrane-enclosed protocells by enzymatic oxidation and cross-linking at the liquid–liquid interface. The oxidation of the tyrosine-rich peptides into dityrosine creates a semipermeable, flexible membrane around the coacervates with tunable thickness, which displays strong intrinsic fluorescence, and stabilizes the coacervate protocells against coalescence. The membranes have an effective molecular weight cut-off of 2.5 kDa, as determined from the partitioning of small dyes and labeled peptides, RNA, and polymers into the membrane-enclosed coacervate protocells. Flicker spectroscopy reveals a membrane bending rigidity of only 0.1kBT, which is substantially lower than phospholipid bilayers despite a larger membrane thickness. Finally, it is shown that enzymes can be stably encapsulated inside the protocells and be supplied with substrates from outside, which opens the way for these membrane-bound compartments to be used as molecularly crowded artificial cells capable of communication or as a vehicle for drug delivery

Summary of TRUEX Radiolysis Testing Using the INL Radiolysis Test Loop

The INL radiolysis and hydrolysis test loop has been used to evaluate the effects of hydrolytic and radiolytic degradation upon the efficacy of the TRUEX flowsheet for the recovery of trivalent actinides and lanthanides from acidic solution. Repeated irradiation and subsequent re-conditioning cycles did result in a significant decrease in the concentration of the TBP and CMPO extractants in the TRUEX solvent and a corresponding decrease in americium and europium extraction distributions. However, the build-up of solvent degradation products upon {gamma}-irradiation, had little impact upon the efficiency of the stripping section of the TRUEX flowsheet. Operation of the TRUEX flowsheet would require careful monitoring to ensure extraction distributions are maintained at acceptable levels